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linux/drivers/md/dm-cache-target.c

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dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix writes to cache device in writethrough mode The dm-cache writethrough strategy introduced by commit e2e74d617eadc15 ("dm cache: fix race in writethrough implementation") issues a bio to the origin device, remaps and then issues the bio to the cache device. This more conservative in-series approach was selected to favor correctness over performance (of the previous parallel writethrough). However, this in-series implementation that reuses the same bio to write both the origin and cache device didn't take into account that the block layer's req_bio_endio() modifies a completing bio's bi_sector and bi_size. So the new writethrough strategy needs to preserve these bio fields, and restore them before submission to the cache device, otherwise nothing gets written to the cache (because bi_size is 0). This patch adds a struct dm_bio_details field to struct per_bio_data, and uses dm_bio_record() and dm_bio_restore() to ensure the bio is restored before reissuing to the cache device. Adding such a large structure to the per_bio_data is not ideal but we can improve this later, for now correctness is the important thing. This problem initially went unnoticed because the dm-cache test-suite uses a linear DM device for the dm-cache device's origin device. Writethrough worked as expected because DM submits a *clone* of the original bio, so the original bio which was reused for the cache was never touched. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-04-05 15:36:32 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm: use time_in_range() and time_after() To be future-proof and for better readability the time comparisons are modified to use time_in_range() and time_after() instead of plain, error-prone math. Signed-off-by: Manuel Schölling <manuel.schoelling@gmx.de> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-05-22 22:42:37 +02:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add io_tracker A little class that keeps track of the volume of io that is in flight, and the length of time that a device has been idle for. FIXME: rather than jiffes, may be best to use ktime_t (to support faster devices). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 13:45:30 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: promotion optimisation for writes If a write block triggers promotion and covers a whole block we can avoid a copy. Introduce dm_{hook,unhook}_bio to simplify saving and restoring bio fields (bi_private is now used by overwrite). Switch writethrough support over to using these helpers too. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:48 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add data block size limits to code and Documentation Place upper bound on the cache's data block size (1GB). Inform users that the data block size can't be any arbitrary number, i.e. its value must be between 32KB and 1GB. Also, it should be a multiple of 32KB. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2013-08-16 10:54:19 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add data block size limits to code and Documentation Place upper bound on the cache's data block size (1GB). Inform users that the data block size can't be any arbitrary number, i.e. its value must be between 32KB and 1GB. Also, it should be a multiple of 32KB. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2013-08-16 10:54:19 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: eliminate holes in cache structure Reorder members in the cache structure to eliminate 6 out of 7 holes (reclaiming 24 bytes). Also, the 'worker' and 'waker' members no longer straddle cachelines. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2013-08-16 10:54:21 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix race in writethrough implementation We have found a race in the optimisation used in the dm cache writethrough implementation. Currently, dm core sends the cache target two bios, one for the origin device and one for the cache device and these are processed in parallel. This patch avoids the race by changing the code back to a simpler (slower) implementation which processes the two writes in series, one after the other, until we can develop a complete fix for the problem. When the cache is in writethrough mode it needs to send WRITE bios to both the origin and cache devices. Previously we've been implementing this by having dm core query the cache target on every write to find out how many copies of the bio it wants. The cache will ask for two bios if the block is in the cache, and one otherwise. Then main problem with this is it's racey. At the time this check is made the bio hasn't yet been submitted and so isn't being taken into account when quiescing a block for migration (promotion or demotion). This means a single bio may be submitted when two were needed because the block has since been promoted to the cache (catastrophic), or two bios where only one is needed (harmless). I really don't want to start entering bios into the quiescing system (deferred_set) in the get_num_write_bios callback. Instead this patch simplifies things; only one bio is submitted by the core, this is first written to the origin and then the cache device in series. Obviously this will have a latency impact. deferred_writethrough_bios is introduced to record bios that must be later issued to the cache device from the worker thread. This deferred submission, after the origin bio completes, is required given that we're in interrupt context (writethrough_endio). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-20 17:21:27 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix a race condition between queuing new migrations and quiescing for a shutdown The code that was trying to do this was inadequate. The postsuspend method (in ioctl context), needs to wait for the worker thread to acknowledge the request to quiesce. Otherwise the migration count may drop to zero temporarily before the worker thread realises we're quiescing. In this case the target will be taken down, but the worker thread may have issued a new migration, which will cause an oops when it completes. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org # 3.9+
2013-10-30 17:11:58 +00:00
dm cache: improve efficiency of quiescing flag management Make the quiescing flag an atomic_t and stop protecting it with a spin lock. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-30 17:29:30 +00:00
dm cache: fix a race condition between queuing new migrations and quiescing for a shutdown The code that was trying to do this was inadequate. The postsuspend method (in ioctl context), needs to wait for the worker thread to acknowledge the request to quiesce. Otherwise the migration count may drop to zero temporarily before the worker thread realises we're quiescing. In this case the target will be taken down, but the worker thread may have issued a new migration, which will cause an oops when it completes. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org # 3.9+
2013-10-30 17:11:58 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix race affecting dirty block count nr_dirty is updated without locking, causing it to drift so that it is non-zero (either a small positive integer, or a very large one when an underflow occurs) even when there are no actual dirty blocks. This was due to a race between the workqueue and map function accessing nr_dirty in parallel without proper protection. People were seeing under runs due to a race on increment/decrement of nr_dirty, see: https://lkml.org/lkml/2014/6/3/648 Fix this by using an atomic_t for nr_dirty. Reported-by: roma1390@gmail.com Signed-off-by: Anssi Hannula <anssi.hannula@iki.fi> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2014-08-01 11:55:47 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: revert "remove remainder of distinct discard block size" This reverts commit 64ab346a360a4b15c28fb8531918d4a01f4eabd9 because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-07 14:47:07 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: revert "prevent corruption caused by discard_block_size > cache_block_size" This reverts commit d132cc6d9e92424bb9d4fd35f5bd0e55d583f4be because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 14:38:01 +00:00
dm cache: eliminate holes in cache structure Reorder members in the cache structure to eliminate 6 out of 7 holes (reclaiming 24 bytes). Also, the 'worker' and 'waker' members no longer straddle cachelines. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2013-08-16 10:54:21 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: eliminate holes in cache structure Reorder members in the cache structure to eliminate 6 out of 7 holes (reclaiming 24 bytes). Also, the 'worker' and 'waker' members no longer straddle cachelines. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2013-08-16 10:54:21 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: eliminate holes in cache structure Reorder members in the cache structure to eliminate 6 out of 7 holes (reclaiming 24 bytes). Also, the 'worker' and 'waker' members no longer straddle cachelines. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2013-08-16 10:54:21 -04:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm cache: track IO to the origin device using io_tracker Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:18:01 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: move hook_info into common portion of per_bio_data structure Commit c9d28d5d ("dm cache: promotion optimisation for writes") incorrectly placed the 'hook_info' member in the writethrough-only portion of the per_bio_data structure. Given that the overwrite optimization may be used for writeback the 'hook_info' member must be placed above the 'cache' member of the per_bio_data structure. Any members above 'cache' are available from both writeback and writethrough modes' per_bio_data structure. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com> Cc: stable@vger.kernel.org # 3.13+
2014-01-31 14:11:54 -05:00
dm cache: track IO to the origin device using io_tracker Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:18:01 +01:00
dm cache: fix race in writethrough implementation We have found a race in the optimisation used in the dm cache writethrough implementation. Currently, dm core sends the cache target two bios, one for the origin device and one for the cache device and these are processed in parallel. This patch avoids the race by changing the code back to a simpler (slower) implementation which processes the two writes in series, one after the other, until we can develop a complete fix for the problem. When the cache is in writethrough mode it needs to send WRITE bios to both the origin and cache devices. Previously we've been implementing this by having dm core query the cache target on every write to find out how many copies of the bio it wants. The cache will ask for two bios if the block is in the cache, and one otherwise. Then main problem with this is it's racey. At the time this check is made the bio hasn't yet been submitted and so isn't being taken into account when quiescing a block for migration (promotion or demotion). This means a single bio may be submitted when two were needed because the block has since been promoted to the cache (catastrophic), or two bios where only one is needed (harmless). I really don't want to start entering bios into the quiescing system (deferred_set) in the get_num_write_bios callback. Instead this patch simplifies things; only one bio is submitted by the core, this is first written to the origin and then the cache device in series. Obviously this will have a latency impact. deferred_writethrough_bios is introduced to record bios that must be later issued to the cache device from the worker thread. This deferred submission, after the origin bio completes, is required given that we're in interrupt context (writethrough_endio). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-20 17:21:27 +00:00
dm cache: reduce bio front_pad size in writeback mode A recent patch to fix the dm cache target's writethrough mode extended the bio's front_pad to include a 1056-byte struct dm_bio_details. Writeback mode doesn't need this, so this patch reduces the per_bio_data_size to 16 bytes in this case instead of 1096. The dm_bio_details structure was added in "dm cache: fix writes to cache device in writethrough mode" which fixed commit e2e74d617e ("dm cache: fix race in writethrough implementation"). In writeback mode we avoid allocating the writethrough-specific members of the per_bio_data structure (the dm_bio_details structure included). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-04-05 15:36:34 +01:00
dm cache: fix typos in comments Fix up some typos in dm-cache comments. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-05-10 14:37:18 +01:00
dm cache: reduce bio front_pad size in writeback mode A recent patch to fix the dm cache target's writethrough mode extended the bio's front_pad to include a 1056-byte struct dm_bio_details. Writeback mode doesn't need this, so this patch reduces the per_bio_data_size to 16 bytes in this case instead of 1096. The dm_bio_details structure was added in "dm cache: fix writes to cache device in writethrough mode" which fixed commit e2e74d617e ("dm cache: fix race in writethrough implementation"). In writeback mode we avoid allocating the writethrough-specific members of the per_bio_data structure (the dm_bio_details structure included). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-04-05 15:36:34 +01:00
dm cache: fix race in writethrough implementation We have found a race in the optimisation used in the dm cache writethrough implementation. Currently, dm core sends the cache target two bios, one for the origin device and one for the cache device and these are processed in parallel. This patch avoids the race by changing the code back to a simpler (slower) implementation which processes the two writes in series, one after the other, until we can develop a complete fix for the problem. When the cache is in writethrough mode it needs to send WRITE bios to both the origin and cache devices. Previously we've been implementing this by having dm core query the cache target on every write to find out how many copies of the bio it wants. The cache will ask for two bios if the block is in the cache, and one otherwise. Then main problem with this is it's racey. At the time this check is made the bio hasn't yet been submitted and so isn't being taken into account when quiescing a block for migration (promotion or demotion). This means a single bio may be submitted when two were needed because the block has since been promoted to the cache (catastrophic), or two bios where only one is needed (harmless). I really don't want to start entering bios into the quiescing system (deferred_set) in the get_num_write_bios callback. Instead this patch simplifies things; only one bio is submitted by the core, this is first written to the origin and then the cache device in series. Obviously this will have a latency impact. deferred_writethrough_bios is introduced to record bios that must be later issued to the cache device from the worker thread. This deferred submission, after the origin bio completes, is required given that we're in interrupt context (writethrough_endio). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-20 17:21:27 +00:00
dm cache: fix writes to cache device in writethrough mode The dm-cache writethrough strategy introduced by commit e2e74d617eadc15 ("dm cache: fix race in writethrough implementation") issues a bio to the origin device, remaps and then issues the bio to the cache device. This more conservative in-series approach was selected to favor correctness over performance (of the previous parallel writethrough). However, this in-series implementation that reuses the same bio to write both the origin and cache device didn't take into account that the block layer's req_bio_endio() modifies a completing bio's bi_sector and bi_size. So the new writethrough strategy needs to preserve these bio fields, and restore them before submission to the cache device, otherwise nothing gets written to the cache (because bi_size is 0). This patch adds a struct dm_bio_details field to struct per_bio_data, and uses dm_bio_record() and dm_bio_restore() to ensure the bio is restored before reissuing to the cache device. Adding such a large structure to the per_bio_data is not ideal but we can improve this later, for now correctness is the important thing. This problem initially went unnoticed because the dm-cache test-suite uses a linear DM device for the dm-cache device's origin device. Writethrough worked as expected because DM submits a *clone* of the original bio, so the original bio which was reused for the cache was never touched. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-04-05 15:36:32 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: promotion optimisation for writes If a write block triggers promotion and covers a whole block we can avoid a copy. Introduce dm_{hook,unhook}_bio to simplify saving and restoring bio fields (bi_private is now used by overwrite). Switch writethrough support over to using these helpers too. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:48 -04:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm cache: wake the worker thread every time we free a migration object When the cache is idle, writeback work was only being issued every second. With this change outstanding writebacks are streamed constantly. This offers a writeback performance improvement. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-27 15:39:45 +01:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm cache: wake the worker thread every time we free a migration object When the cache is idle, writeback work was only being issued every second. With this change outstanding writebacks are streamed constantly. This offers a writeback performance improvement. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-27 15:39:45 +01:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix typos in comments Fix up some typos in dm-cache comments. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-05-10 14:37:18 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix race affecting dirty block count nr_dirty is updated without locking, causing it to drift so that it is non-zero (either a small positive integer, or a very large one when an underflow occurs) even when there are no actual dirty blocks. This was due to a race between the workqueue and map function accessing nr_dirty in parallel without proper protection. People were seeing under runs due to a race on increment/decrement of nr_dirty, see: https://lkml.org/lkml/2014/6/3/648 Fix this by using an atomic_t for nr_dirty. Reported-by: roma1390@gmail.com Signed-off-by: Anssi Hannula <anssi.hannula@iki.fi> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2014-08-01 11:55:47 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix race affecting dirty block count nr_dirty is updated without locking, causing it to drift so that it is non-zero (either a small positive integer, or a very large one when an underflow occurs) even when there are no actual dirty blocks. This was due to a race between the workqueue and map function accessing nr_dirty in parallel without proper protection. People were seeing under runs due to a race on increment/decrement of nr_dirty, see: https://lkml.org/lkml/2014/6/3/648 Fix this by using an atomic_t for nr_dirty. Reported-by: roma1390@gmail.com Signed-off-by: Anssi Hannula <anssi.hannula@iki.fi> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2014-08-01 11:55:47 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix typos in comments Fix up some typos in dm-cache comments. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-05-10 14:37:18 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix arm link errors with inline Use __always_inline to avoid a link failure with gcc 4.6 on ARM. gcc 4.7 is OK. It creates a function block_div.part.8, it references __udivdi3 and __umoddi3 and it is never called. The references to __udivdi3 and __umoddi3 cause a link failure. Reported-by: Rob Herring <robherring2@gmail.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-10 23:41:17 +01:00
dm cache: avoid 64 bit division on 32 bit Squash various 32bit link errors. >> on i386: >> drivers/built-in.o: In function `is_discarded_oblock': >> dm-cache-target.c:(.text+0x1ea28e): undefined reference to `__udivdi3' ... Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-20 17:21:25 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm cache: revert "remove remainder of distinct discard block size" This reverts commit 64ab346a360a4b15c28fb8531918d4a01f4eabd9 because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-07 14:47:07 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm cache: revert "remove remainder of distinct discard block size" This reverts commit 64ab346a360a4b15c28fb8531918d4a01f4eabd9 because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-07 14:47:07 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm cache: revert "remove remainder of distinct discard block size" This reverts commit 64ab346a360a4b15c28fb8531918d4a01f4eabd9 because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-07 14:47:07 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: revert "remove remainder of distinct discard block size" This reverts commit 64ab346a360a4b15c28fb8531918d4a01f4eabd9 because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-07 14:47:07 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: revert "remove remainder of distinct discard block size" This reverts commit 64ab346a360a4b15c28fb8531918d4a01f4eabd9 because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-07 14:47:07 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: revert "remove remainder of distinct discard block size" This reverts commit 64ab346a360a4b15c28fb8531918d4a01f4eabd9 because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-07 14:47:07 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: revert "remove remainder of distinct discard block size" This reverts commit 64ab346a360a4b15c28fb8531918d4a01f4eabd9 because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-07 14:47:07 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: revert "remove remainder of distinct discard block size" This reverts commit 64ab346a360a4b15c28fb8531918d4a01f4eabd9 because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-07 14:47:07 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: revert "remove remainder of distinct discard block size" This reverts commit 64ab346a360a4b15c28fb8531918d4a01f4eabd9 because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-07 14:47:07 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: reduce bio front_pad size in writeback mode A recent patch to fix the dm cache target's writethrough mode extended the bio's front_pad to include a 1056-byte struct dm_bio_details. Writeback mode doesn't need this, so this patch reduces the per_bio_data_size to 16 bytes in this case instead of 1096. The dm_bio_details structure was added in "dm cache: fix writes to cache device in writethrough mode" which fixed commit e2e74d617e ("dm cache: fix race in writethrough implementation"). In writeback mode we avoid allocating the writethrough-specific members of the per_bio_data structure (the dm_bio_details structure included). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-04-05 15:36:34 +01:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm cache: reduce bio front_pad size in writeback mode A recent patch to fix the dm cache target's writethrough mode extended the bio's front_pad to include a 1056-byte struct dm_bio_details. Writeback mode doesn't need this, so this patch reduces the per_bio_data_size to 16 bytes in this case instead of 1096. The dm_bio_details structure was added in "dm cache: fix writes to cache device in writethrough mode" which fixed commit e2e74d617e ("dm cache: fix race in writethrough implementation"). In writeback mode we avoid allocating the writethrough-specific members of the per_bio_data structure (the dm_bio_details structure included). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-04-05 15:36:34 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm cache: reduce bio front_pad size in writeback mode A recent patch to fix the dm cache target's writethrough mode extended the bio's front_pad to include a 1056-byte struct dm_bio_details. Writeback mode doesn't need this, so this patch reduces the per_bio_data_size to 16 bytes in this case instead of 1096. The dm_bio_details structure was added in "dm cache: fix writes to cache device in writethrough mode" which fixed commit e2e74d617e ("dm cache: fix race in writethrough implementation"). In writeback mode we avoid allocating the writethrough-specific members of the per_bio_data structure (the dm_bio_details structure included). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-04-05 15:36:34 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: reduce bio front_pad size in writeback mode A recent patch to fix the dm cache target's writethrough mode extended the bio's front_pad to include a 1056-byte struct dm_bio_details. Writeback mode doesn't need this, so this patch reduces the per_bio_data_size to 16 bytes in this case instead of 1096. The dm_bio_details structure was added in "dm cache: fix writes to cache device in writethrough mode" which fixed commit e2e74d617e ("dm cache: fix race in writethrough implementation"). In writeback mode we avoid allocating the writethrough-specific members of the per_bio_data structure (the dm_bio_details structure included). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-04-05 15:36:34 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: reduce bio front_pad size in writeback mode A recent patch to fix the dm cache target's writethrough mode extended the bio's front_pad to include a 1056-byte struct dm_bio_details. Writeback mode doesn't need this, so this patch reduces the per_bio_data_size to 16 bytes in this case instead of 1096. The dm_bio_details structure was added in "dm cache: fix writes to cache device in writethrough mode" which fixed commit e2e74d617e ("dm cache: fix race in writethrough implementation"). In writeback mode we avoid allocating the writethrough-specific members of the per_bio_data structure (the dm_bio_details structure included). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-04-05 15:36:34 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: track IO to the origin device using io_tracker Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:18:01 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
block: Abstract out bvec iterator Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-10-11 15:44:27 -07:00
dm cache: fix truncation bug when mapping I/O to >2TB fast device When remapping a block to the cache's fast device that is larger than 2TB we must not truncate the destination sector to 32bits. The 32bit temporary result of from_cblock() was being overflowed in remap_to_cache() due to the logical left shift. Use an intermediate 64bit type to store the 32bit from_cblock() result to fix the overflow. Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2014-02-27 22:46:48 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
block: Abstract out bvec iterator Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-10-11 15:44:27 -07:00
dm cache: fix truncation bug when mapping I/O to >2TB fast device When remapping a block to the cache's fast device that is larger than 2TB we must not truncate the destination sector to 32bits. The 32bit temporary result of from_cblock() was being overflowed in remap_to_cache() due to the logical left shift. Use an intermediate 64bit type to store the 32bit from_cblock() result to fix the overflow. Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2014-02-27 22:46:48 +01:00
block: Abstract out bvec iterator Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-10-11 15:44:27 -07:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
block: Abstract out bvec iterator Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-10-11 15:44:27 -07:00
dm cache: fix truncation bug when mapping I/O to >2TB fast device When remapping a block to the cache's fast device that is larger than 2TB we must not truncate the destination sector to 32bits. The 32bit temporary result of from_cblock() was being overflowed in remap_to_cache() due to the logical left shift. Use an intermediate 64bit type to store the 32bit from_cblock() result to fix the overflow. Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2014-02-27 22:46:48 +01:00
block: Abstract out bvec iterator Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-10-11 15:44:27 -07:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: reduce bio front_pad size in writeback mode A recent patch to fix the dm cache target's writethrough mode extended the bio's front_pad to include a 1056-byte struct dm_bio_details. Writeback mode doesn't need this, so this patch reduces the per_bio_data_size to 16 bytes in this case instead of 1096. The dm_bio_details structure was added in "dm cache: fix writes to cache device in writethrough mode" which fixed commit e2e74d617e ("dm cache: fix race in writethrough implementation"). In writeback mode we avoid allocating the writethrough-specific members of the per_bio_data structure (the dm_bio_details structure included). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-04-05 15:36:34 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: revert "remove remainder of distinct discard block size" This reverts commit 64ab346a360a4b15c28fb8531918d4a01f4eabd9 because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-07 14:47:07 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: io destined for the cache device can now serve as tick bios Previously only origin bios could trigger ticks, which meant if all the io was destined for the cache no ticks were generated. If no ticks are generated then multiple hits, and movements in general, are attributed to the same tick. Only a stop gap fix, we need a better solution. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-21 12:51:45 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: revert "remove remainder of distinct discard block size" This reverts commit 64ab346a360a4b15c28fb8531918d4a01f4eabd9 because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-07 14:47:07 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
block: Abstract out bvec iterator Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-10-11 15:44:27 -07:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: simplify deferred set reference count increments Factor out inc_and_issue and inc_ds helpers to simplify deferred set reference count increments. Also cleanup cache_map to consistently call cell_defer and inc_ds when the bio is DM_MAPIO_REMAPPED. No functional change. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-05-13 16:18:38 +01:00
dm cache: track IO to the origin device using io_tracker Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:18:01 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: track IO to the origin device using io_tracker Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:18:01 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: simplify deferred set reference count increments Factor out inc_and_issue and inc_ds helpers to simplify deferred set reference count increments. Also cleanup cache_map to consistently call cell_defer and inc_ds when the bio is DM_MAPIO_REMAPPED. No functional change. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-05-13 16:18:38 +01:00
dm cache: fix race in writethrough implementation We have found a race in the optimisation used in the dm cache writethrough implementation. Currently, dm core sends the cache target two bios, one for the origin device and one for the cache device and these are processed in parallel. This patch avoids the race by changing the code back to a simpler (slower) implementation which processes the two writes in series, one after the other, until we can develop a complete fix for the problem. When the cache is in writethrough mode it needs to send WRITE bios to both the origin and cache devices. Previously we've been implementing this by having dm core query the cache target on every write to find out how many copies of the bio it wants. The cache will ask for two bios if the block is in the cache, and one otherwise. Then main problem with this is it's racey. At the time this check is made the bio hasn't yet been submitted and so isn't being taken into account when quiescing a block for migration (promotion or demotion). This means a single bio may be submitted when two were needed because the block has since been promoted to the cache (catastrophic), or two bios where only one is needed (harmless). I really don't want to start entering bios into the quiescing system (deferred_set) in the get_num_write_bios callback. Instead this patch simplifies things; only one bio is submitted by the core, this is first written to the origin and then the cache device in series. Obviously this will have a latency impact. deferred_writethrough_bios is introduced to record bios that must be later issued to the cache device from the worker thread. This deferred submission, after the origin bio completes, is required given that we're in interrupt context (writethrough_endio). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-20 17:21:27 +00:00
block: add a bi_error field to struct bio Currently we have two different ways to signal an I/O error on a BIO: (1) by clearing the BIO_UPTODATE flag (2) by returning a Linux errno value to the bi_end_io callback The first one has the drawback of only communicating a single possible error (-EIO), and the second one has the drawback of not beeing persistent when bios are queued up, and are not passed along from child to parent bio in the ever more popular chaining scenario. Having both mechanisms available has the additional drawback of utterly confusing driver authors and introducing bugs where various I/O submitters only deal with one of them, and the others have to add boilerplate code to deal with both kinds of error returns. So add a new bi_error field to store an errno value directly in struct bio and remove the existing mechanisms to clean all this up. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-07-20 15:29:37 +02:00
dm cache: fix race in writethrough implementation We have found a race in the optimisation used in the dm cache writethrough implementation. Currently, dm core sends the cache target two bios, one for the origin device and one for the cache device and these are processed in parallel. This patch avoids the race by changing the code back to a simpler (slower) implementation which processes the two writes in series, one after the other, until we can develop a complete fix for the problem. When the cache is in writethrough mode it needs to send WRITE bios to both the origin and cache devices. Previously we've been implementing this by having dm core query the cache target on every write to find out how many copies of the bio it wants. The cache will ask for two bios if the block is in the cache, and one otherwise. Then main problem with this is it's racey. At the time this check is made the bio hasn't yet been submitted and so isn't being taken into account when quiescing a block for migration (promotion or demotion). This means a single bio may be submitted when two were needed because the block has since been promoted to the cache (catastrophic), or two bios where only one is needed (harmless). I really don't want to start entering bios into the quiescing system (deferred_set) in the get_num_write_bios callback. Instead this patch simplifies things; only one bio is submitted by the core, this is first written to the origin and then the cache device in series. Obviously this will have a latency impact. deferred_writethrough_bios is introduced to record bios that must be later issued to the cache device from the worker thread. This deferred submission, after the origin bio completes, is required given that we're in interrupt context (writethrough_endio). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-20 17:21:27 +00:00
dm cache: reduce bio front_pad size in writeback mode A recent patch to fix the dm cache target's writethrough mode extended the bio's front_pad to include a 1056-byte struct dm_bio_details. Writeback mode doesn't need this, so this patch reduces the per_bio_data_size to 16 bytes in this case instead of 1096. The dm_bio_details structure was added in "dm cache: fix writes to cache device in writethrough mode" which fixed commit e2e74d617e ("dm cache: fix race in writethrough implementation"). In writeback mode we avoid allocating the writethrough-specific members of the per_bio_data structure (the dm_bio_details structure included). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-04-05 15:36:34 +01:00
dm cache: promotion optimisation for writes If a write block triggers promotion and covers a whole block we can avoid a copy. Introduce dm_{hook,unhook}_bio to simplify saving and restoring bio fields (bi_private is now used by overwrite). Switch writethrough support over to using these helpers too. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:48 -04:00
dm cache: fix race in writethrough implementation We have found a race in the optimisation used in the dm cache writethrough implementation. Currently, dm core sends the cache target two bios, one for the origin device and one for the cache device and these are processed in parallel. This patch avoids the race by changing the code back to a simpler (slower) implementation which processes the two writes in series, one after the other, until we can develop a complete fix for the problem. When the cache is in writethrough mode it needs to send WRITE bios to both the origin and cache devices. Previously we've been implementing this by having dm core query the cache target on every write to find out how many copies of the bio it wants. The cache will ask for two bios if the block is in the cache, and one otherwise. Then main problem with this is it's racey. At the time this check is made the bio hasn't yet been submitted and so isn't being taken into account when quiescing a block for migration (promotion or demotion). This means a single bio may be submitted when two were needed because the block has since been promoted to the cache (catastrophic), or two bios where only one is needed (harmless). I really don't want to start entering bios into the quiescing system (deferred_set) in the get_num_write_bios callback. Instead this patch simplifies things; only one bio is submitted by the core, this is first written to the origin and then the cache device in series. Obviously this will have a latency impact. deferred_writethrough_bios is introduced to record bios that must be later issued to the cache device from the worker thread. This deferred submission, after the origin bio completes, is required given that we're in interrupt context (writethrough_endio). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-20 17:21:27 +00:00
block: add a bi_error field to struct bio Currently we have two different ways to signal an I/O error on a BIO: (1) by clearing the BIO_UPTODATE flag (2) by returning a Linux errno value to the bi_end_io callback The first one has the drawback of only communicating a single possible error (-EIO), and the second one has the drawback of not beeing persistent when bios are queued up, and are not passed along from child to parent bio in the ever more popular chaining scenario. Having both mechanisms available has the additional drawback of utterly confusing driver authors and introducing bugs where various I/O submitters only deal with one of them, and the others have to add boilerplate code to deal with both kinds of error returns. So add a new bi_error field to store an errno value directly in struct bio and remove the existing mechanisms to clean all this up. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-07-20 15:29:37 +02:00
dm cache: fix race in writethrough implementation We have found a race in the optimisation used in the dm cache writethrough implementation. Currently, dm core sends the cache target two bios, one for the origin device and one for the cache device and these are processed in parallel. This patch avoids the race by changing the code back to a simpler (slower) implementation which processes the two writes in series, one after the other, until we can develop a complete fix for the problem. When the cache is in writethrough mode it needs to send WRITE bios to both the origin and cache devices. Previously we've been implementing this by having dm core query the cache target on every write to find out how many copies of the bio it wants. The cache will ask for two bios if the block is in the cache, and one otherwise. Then main problem with this is it's racey. At the time this check is made the bio hasn't yet been submitted and so isn't being taken into account when quiescing a block for migration (promotion or demotion). This means a single bio may be submitted when two were needed because the block has since been promoted to the cache (catastrophic), or two bios where only one is needed (harmless). I really don't want to start entering bios into the quiescing system (deferred_set) in the get_num_write_bios callback. Instead this patch simplifies things; only one bio is submitted by the core, this is first written to the origin and then the cache device in series. Obviously this will have a latency impact. deferred_writethrough_bios is introduced to record bios that must be later issued to the cache device from the worker thread. This deferred submission, after the origin bio completes, is required given that we're in interrupt context (writethrough_endio). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-20 17:21:27 +00:00
dm cache: fix writes to cache device in writethrough mode The dm-cache writethrough strategy introduced by commit e2e74d617eadc15 ("dm cache: fix race in writethrough implementation") issues a bio to the origin device, remaps and then issues the bio to the cache device. This more conservative in-series approach was selected to favor correctness over performance (of the previous parallel writethrough). However, this in-series implementation that reuses the same bio to write both the origin and cache device didn't take into account that the block layer's req_bio_endio() modifies a completing bio's bi_sector and bi_size. So the new writethrough strategy needs to preserve these bio fields, and restore them before submission to the cache device, otherwise nothing gets written to the cache (because bi_size is 0). This patch adds a struct dm_bio_details field to struct per_bio_data, and uses dm_bio_record() and dm_bio_restore() to ensure the bio is restored before reissuing to the cache device. Adding such a large structure to the per_bio_data is not ideal but we can improve this later, for now correctness is the important thing. This problem initially went unnoticed because the dm-cache test-suite uses a linear DM device for the dm-cache device's origin device. Writethrough worked as expected because DM submits a *clone* of the original bio, so the original bio which was reused for the cache was never touched. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-04-05 15:36:32 +01:00
dm cache: fix race in writethrough implementation We have found a race in the optimisation used in the dm cache writethrough implementation. Currently, dm core sends the cache target two bios, one for the origin device and one for the cache device and these are processed in parallel. This patch avoids the race by changing the code back to a simpler (slower) implementation which processes the two writes in series, one after the other, until we can develop a complete fix for the problem. When the cache is in writethrough mode it needs to send WRITE bios to both the origin and cache devices. Previously we've been implementing this by having dm core query the cache target on every write to find out how many copies of the bio it wants. The cache will ask for two bios if the block is in the cache, and one otherwise. Then main problem with this is it's racey. At the time this check is made the bio hasn't yet been submitted and so isn't being taken into account when quiescing a block for migration (promotion or demotion). This means a single bio may be submitted when two were needed because the block has since been promoted to the cache (catastrophic), or two bios where only one is needed (harmless). I really don't want to start entering bios into the quiescing system (deferred_set) in the get_num_write_bios callback. Instead this patch simplifies things; only one bio is submitted by the core, this is first written to the origin and then the cache device in series. Obviously this will have a latency impact. deferred_writethrough_bios is introduced to record bios that must be later issued to the cache device from the worker thread. This deferred submission, after the origin bio completes, is required given that we're in interrupt context (writethrough_endio). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-20 17:21:27 +00:00
dm cache: fix typos in comments Fix up some typos in dm-cache comments. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-05-10 14:37:18 +01:00
dm cache: fix race in writethrough implementation We have found a race in the optimisation used in the dm cache writethrough implementation. Currently, dm core sends the cache target two bios, one for the origin device and one for the cache device and these are processed in parallel. This patch avoids the race by changing the code back to a simpler (slower) implementation which processes the two writes in series, one after the other, until we can develop a complete fix for the problem. When the cache is in writethrough mode it needs to send WRITE bios to both the origin and cache devices. Previously we've been implementing this by having dm core query the cache target on every write to find out how many copies of the bio it wants. The cache will ask for two bios if the block is in the cache, and one otherwise. Then main problem with this is it's racey. At the time this check is made the bio hasn't yet been submitted and so isn't being taken into account when quiescing a block for migration (promotion or demotion). This means a single bio may be submitted when two were needed because the block has since been promoted to the cache (catastrophic), or two bios where only one is needed (harmless). I really don't want to start entering bios into the quiescing system (deferred_set) in the get_num_write_bios callback. Instead this patch simplifies things; only one bio is submitted by the core, this is first written to the origin and then the cache device in series. Obviously this will have a latency impact. deferred_writethrough_bios is introduced to record bios that must be later issued to the cache device from the worker thread. This deferred submission, after the origin bio completes, is required given that we're in interrupt context (writethrough_endio). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-20 17:21:27 +00:00
dm cache: reduce bio front_pad size in writeback mode A recent patch to fix the dm cache target's writethrough mode extended the bio's front_pad to include a 1056-byte struct dm_bio_details. Writeback mode doesn't need this, so this patch reduces the per_bio_data_size to 16 bytes in this case instead of 1096. The dm_bio_details structure was added in "dm cache: fix writes to cache device in writethrough mode" which fixed commit e2e74d617e ("dm cache: fix race in writethrough implementation"). In writeback mode we avoid allocating the writethrough-specific members of the per_bio_data structure (the dm_bio_details structure included). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-04-05 15:36:34 +01:00
dm cache: fix race in writethrough implementation We have found a race in the optimisation used in the dm cache writethrough implementation. Currently, dm core sends the cache target two bios, one for the origin device and one for the cache device and these are processed in parallel. This patch avoids the race by changing the code back to a simpler (slower) implementation which processes the two writes in series, one after the other, until we can develop a complete fix for the problem. When the cache is in writethrough mode it needs to send WRITE bios to both the origin and cache devices. Previously we've been implementing this by having dm core query the cache target on every write to find out how many copies of the bio it wants. The cache will ask for two bios if the block is in the cache, and one otherwise. Then main problem with this is it's racey. At the time this check is made the bio hasn't yet been submitted and so isn't being taken into account when quiescing a block for migration (promotion or demotion). This means a single bio may be submitted when two were needed because the block has since been promoted to the cache (catastrophic), or two bios where only one is needed (harmless). I really don't want to start entering bios into the quiescing system (deferred_set) in the get_num_write_bios callback. Instead this patch simplifies things; only one bio is submitted by the core, this is first written to the origin and then the cache device in series. Obviously this will have a latency impact. deferred_writethrough_bios is introduced to record bios that must be later issued to the cache device from the worker thread. This deferred submission, after the origin bio completes, is required given that we're in interrupt context (writethrough_endio). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-20 17:21:27 +00:00
dm cache: promotion optimisation for writes If a write block triggers promotion and covers a whole block we can avoid a copy. Introduce dm_{hook,unhook}_bio to simplify saving and restoring bio fields (bi_private is now used by overwrite). Switch writethrough support over to using these helpers too. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:48 -04:00
dm cache: fix writes to cache device in writethrough mode The dm-cache writethrough strategy introduced by commit e2e74d617eadc15 ("dm cache: fix race in writethrough implementation") issues a bio to the origin device, remaps and then issues the bio to the cache device. This more conservative in-series approach was selected to favor correctness over performance (of the previous parallel writethrough). However, this in-series implementation that reuses the same bio to write both the origin and cache device didn't take into account that the block layer's req_bio_endio() modifies a completing bio's bi_sector and bi_size. So the new writethrough strategy needs to preserve these bio fields, and restore them before submission to the cache device, otherwise nothing gets written to the cache (because bi_size is 0). This patch adds a struct dm_bio_details field to struct per_bio_data, and uses dm_bio_record() and dm_bio_restore() to ensure the bio is restored before reissuing to the cache device. Adding such a large structure to the per_bio_data is not ideal but we can improve this later, for now correctness is the important thing. This problem initially went unnoticed because the dm-cache test-suite uses a linear DM device for the dm-cache device's origin device. Writethrough worked as expected because DM submits a *clone* of the original bio, so the original bio which was reused for the cache was never touched. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-04-05 15:36:32 +01:00
dm cache: fix race in writethrough implementation We have found a race in the optimisation used in the dm cache writethrough implementation. Currently, dm core sends the cache target two bios, one for the origin device and one for the cache device and these are processed in parallel. This patch avoids the race by changing the code back to a simpler (slower) implementation which processes the two writes in series, one after the other, until we can develop a complete fix for the problem. When the cache is in writethrough mode it needs to send WRITE bios to both the origin and cache devices. Previously we've been implementing this by having dm core query the cache target on every write to find out how many copies of the bio it wants. The cache will ask for two bios if the block is in the cache, and one otherwise. Then main problem with this is it's racey. At the time this check is made the bio hasn't yet been submitted and so isn't being taken into account when quiescing a block for migration (promotion or demotion). This means a single bio may be submitted when two were needed because the block has since been promoted to the cache (catastrophic), or two bios where only one is needed (harmless). I really don't want to start entering bios into the quiescing system (deferred_set) in the get_num_write_bios callback. Instead this patch simplifies things; only one bio is submitted by the core, this is first written to the origin and then the cache device in series. Obviously this will have a latency impact. deferred_writethrough_bios is introduced to record bios that must be later issued to the cache device from the worker thread. This deferred submission, after the origin bio completes, is required given that we're in interrupt context (writethrough_endio). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-20 17:21:27 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm cache: make sure every metadata function checks fail_io commit d14fcf3dd79c0b8a8d0ba469c44a6b04f3a1403b upstream. Otherwise operations may be attempted that will only ever go on to crash (since the metadata device is either missing or unreliable if 'fail_io' is set). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-10 16:20:58 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm cache: make sure every metadata function checks fail_io commit d14fcf3dd79c0b8a8d0ba469c44a6b04f3a1403b upstream. Otherwise operations may be attempted that will only ever go on to crash (since the metadata device is either missing or unreliable if 'fail_io' is set). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-10 16:20:58 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm cache: small cleanups related to deferred prison cell cleanup Eliminate __cell_release() since it only had one caller that always released the cell holder. Switch cell_error_with_code() to using free_prison_cell() for the sake of consistency. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-08-31 15:41:34 -04:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm cache: small cleanups related to deferred prison cell cleanup Eliminate __cell_release() since it only had one caller that always released the cell holder. Switch cell_error_with_code() to using free_prison_cell() for the sake of consistency. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-08-31 15:41:34 -04:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm cache: small cleanups related to deferred prison cell cleanup Eliminate __cell_release() since it only had one caller that always released the cell holder. Switch cell_error_with_code() to using free_prison_cell() for the sake of consistency. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-08-31 15:41:34 -04:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm cache: small cleanups related to deferred prison cell cleanup Eliminate __cell_release() since it only had one caller that always released the cell holder. Switch cell_error_with_code() to using free_prison_cell() for the sake of consistency. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-08-31 15:41:34 -04:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix use after freeing migrations Both free_io_migration() and issue_discard() dereference a migration that was just freed. Fix those by saving off the migrations's cache object before freeing the migration. Also cleanup needless mg->cache dereferences now that the cache object is available directly. Fixes: e44b6a5a3c ("dm cache: move wake_waker() from free_migrations() to where it is needed") Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-09-01 11:38:19 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix use after freeing migrations Both free_io_migration() and issue_discard() dereference a migration that was just freed. Fix those by saving off the migrations's cache object before freeing the migration. Also cleanup needless mg->cache dereferences now that the cache object is available directly. Fixes: e44b6a5a3c ("dm cache: move wake_waker() from free_migrations() to where it is needed") Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-09-01 11:38:19 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: use cell_defer() boolean argument consistently Fix a few cell_defer() calls that weren't passing a bool. Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-14 17:10:47 +02:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: use cell_defer() boolean argument consistently Fix a few cell_defer() calls that weren't passing a bool. Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-14 17:10:47 +02:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: use cell_defer() boolean argument consistently Fix a few cell_defer() calls that weren't passing a bool. Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-14 17:10:47 +02:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix race causing dirty blocks to be marked as clean When a writeback or a promotion of a block is completed, the cell of that block is removed from the prison, the block is marked as clean, and the clear_dirty() callback of the cache policy is called. Unfortunately, performing those actions in this order allows an incoming new write bio for that block to come in before clearing the dirty status is completed and therefore possibly causing one of these two scenarios: Scenario A: Thread 1 Thread 2 cell_defer() . - cell removed from prison . - detained bios queued . . incoming write bio . remapped to cache . set_dirty() called, . but block already dirty . => it does nothing clear_dirty() . - block marked clean . - policy clear_dirty() called . Result: Block is marked clean even though it is actually dirty. No writeback will occur. Scenario B: Thread 1 Thread 2 cell_defer() . - cell removed from prison . - detained bios queued . clear_dirty() . - block marked clean . . incoming write bio . remapped to cache . set_dirty() called . - block marked dirty . - policy set_dirty() called - policy clear_dirty() called . Result: Block is properly marked as dirty, but policy thinks it is clean and therefore never asks us to writeback it. This case is visible in "dmsetup status" dirty block count (which normally decreases to 0 on a quiet device). Fix these issues by calling clear_dirty() before calling cell_defer(). Incoming bios for that block will then be detained in the cell and released only after clear_dirty() has completed, so the race will not occur. Found by inspecting the code after noticing spurious dirty counts (scenario B). Signed-off-by: Anssi Hannula <anssi.hannula@iki.fi> Acked-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2014-09-05 03:11:28 +03:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: use cell_defer() boolean argument consistently Fix a few cell_defer() calls that weren't passing a bool. Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-14 17:10:47 +02:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: dirty flag was mistakenly being cleared when promoting via overwrite If the incoming bio is a WRITE and completely covers a block then we don't bother to do any copying for a promotion operation. Once this is done the cache block and origin block will be different, so we need to set it to 'dirty'. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2014-11-27 12:26:46 +00:00
dm cache: promotion optimisation for writes If a write block triggers promotion and covers a whole block we can avoid a copy. Introduce dm_{hook,unhook}_bio to simplify saving and restoring bio fields (bi_private is now used by overwrite). Switch writethrough support over to using these helpers too. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:48 -04:00
dm cache: dirty flag was mistakenly being cleared when promoting via overwrite If the incoming bio is a WRITE and completely covers a block then we don't bother to do any copying for a promotion operation. Once this is done the cache block and origin block will be different, so we need to set it to 'dirty'. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2014-11-27 12:26:46 +00:00
block: add a bi_error field to struct bio Currently we have two different ways to signal an I/O error on a BIO: (1) by clearing the BIO_UPTODATE flag (2) by returning a Linux errno value to the bi_end_io callback The first one has the drawback of only communicating a single possible error (-EIO), and the second one has the drawback of not beeing persistent when bios are queued up, and are not passed along from child to parent bio in the ever more popular chaining scenario. Having both mechanisms available has the additional drawback of utterly confusing driver authors and introducing bugs where various I/O submitters only deal with one of them, and the others have to add boilerplate code to deal with both kinds of error returns. So add a new bi_error field to store an errno value directly in struct bio and remove the existing mechanisms to clean all this up. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-07-20 15:29:37 +02:00
dm cache: promotion optimisation for writes If a write block triggers promotion and covers a whole block we can avoid a copy. Introduce dm_{hook,unhook}_bio to simplify saving and restoring bio fields (bi_private is now used by overwrite). Switch writethrough support over to using these helpers too. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:48 -04:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix truncation bug when copying a block to/from >2TB fast device During demotion or promotion to a cache's >2TB fast device we must not truncate the cache block's associated sector to 32bits. The 32bit temporary result of from_cblock() caused a 32bit multiplication when calculating the sector of the fast device in issue_copy_real(). Use an intermediate 64bit type to store the 32bit from_cblock() to allow for proper 64bit multiplication. Here is an example of how this bug manifests on an ext4 filesystem: EXT4-fs error (device dm-0): ext4_mb_generate_buddy:756: group 17136, 32768 clusters in bitmap, 30688 in gd; block bitmap corrupt. JBD2: Spotted dirty metadata buffer (dev = dm-0, blocknr = 0). There's a risk of filesystem corruption in case of system crash. Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2014-03-12 00:40:05 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix truncation bug when copying a block to/from >2TB fast device During demotion or promotion to a cache's >2TB fast device we must not truncate the cache block's associated sector to 32bits. The 32bit temporary result of from_cblock() caused a 32bit multiplication when calculating the sector of the fast device in issue_copy_real(). Use an intermediate 64bit type to store the 32bit from_cblock() to allow for proper 64bit multiplication. Here is an example of how this bug manifests on an ext4 filesystem: EXT4-fs error (device dm-0): ext4_mb_generate_buddy:756: group 17136, 32768 clusters in bitmap, 30688 in gd; block bitmap corrupt. JBD2: Spotted dirty metadata buffer (dev = dm-0, blocknr = 0). There's a risk of filesystem corruption in case of system crash. Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2014-03-12 00:40:05 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: log error message if dm_kcopyd_copy() fails A migration failure should be logged (albeit limited). Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-14 17:14:45 +02:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: log error message if dm_kcopyd_copy() fails A migration failure should be logged (albeit limited). Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-14 17:14:45 +02:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
block: add a bi_error field to struct bio Currently we have two different ways to signal an I/O error on a BIO: (1) by clearing the BIO_UPTODATE flag (2) by returning a Linux errno value to the bi_end_io callback The first one has the drawback of only communicating a single possible error (-EIO), and the second one has the drawback of not beeing persistent when bios are queued up, and are not passed along from child to parent bio in the ever more popular chaining scenario. Having both mechanisms available has the additional drawback of utterly confusing driver authors and introducing bugs where various I/O submitters only deal with one of them, and the others have to add boilerplate code to deal with both kinds of error returns. So add a new bi_error field to store an errno value directly in struct bio and remove the existing mechanisms to clean all this up. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-07-20 15:29:37 +02:00
dm cache: promotion optimisation for writes If a write block triggers promotion and covers a whole block we can avoid a copy. Introduce dm_{hook,unhook}_bio to simplify saving and restoring bio fields (bi_private is now used by overwrite). Switch writethrough support over to using these helpers too. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:48 -04:00
dm cache: do not add migration to completed list before unhooking bio When completing an overwrite bio, in overwrite_endio(), the associated migration should not be added to the 'completed_migrations' until the bio's fields are restored with dm_unhook_bio(). Otherwise, do_worker() can race to process 'completed_migrations' before dm_unhook_bio() -- so the bio's bi_end_io is incorrect. This is unlikely to cause any problems given the current code but should be fixed on the basis of correctness. Also, the cache's spinlock only needs to be held when manipulating the 'completed_migrations' list -- other changes don't need protection. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2014-01-31 14:30:37 -05:00
block: add a bi_error field to struct bio Currently we have two different ways to signal an I/O error on a BIO: (1) by clearing the BIO_UPTODATE flag (2) by returning a Linux errno value to the bi_end_io callback The first one has the drawback of only communicating a single possible error (-EIO), and the second one has the drawback of not beeing persistent when bios are queued up, and are not passed along from child to parent bio in the ever more popular chaining scenario. Having both mechanisms available has the additional drawback of utterly confusing driver authors and introducing bugs where various I/O submitters only deal with one of them, and the others have to add boilerplate code to deal with both kinds of error returns. So add a new bi_error field to store an errno value directly in struct bio and remove the existing mechanisms to clean all this up. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-07-20 15:29:37 +02:00
dm cache: promotion optimisation for writes If a write block triggers promotion and covers a whole block we can avoid a copy. Introduce dm_{hook,unhook}_bio to simplify saving and restoring bio fields (bi_private is now used by overwrite). Switch writethrough support over to using these helpers too. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:48 -04:00
dm cache: do not add migration to completed list before unhooking bio When completing an overwrite bio, in overwrite_endio(), the associated migration should not be added to the 'completed_migrations' until the bio's fields are restored with dm_unhook_bio(). Otherwise, do_worker() can race to process 'completed_migrations' before dm_unhook_bio() -- so the bio's bi_end_io is incorrect. This is unlikely to cause any problems given the current code but should be fixed on the basis of correctness. Also, the cache's spinlock only needs to be held when manipulating the 'completed_migrations' list -- other changes don't need protection. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2014-01-31 14:30:37 -05:00
dm cache: promotion optimisation for writes If a write block triggers promotion and covers a whole block we can avoid a copy. Introduce dm_{hook,unhook}_bio to simplify saving and restoring bio fields (bi_private is now used by overwrite). Switch writethrough support over to using these helpers too. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:48 -04:00
dm cache: simplify deferred set reference count increments Factor out inc_and_issue and inc_ds helpers to simplify deferred set reference count increments. Also cleanup cache_map to consistently call cell_defer and inc_ds when the bio is DM_MAPIO_REMAPPED. No functional change. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-05-13 16:18:38 +01:00
dm cache: track IO to the origin device using io_tracker Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:18:01 +01:00
dm cache: promotion optimisation for writes If a write block triggers promotion and covers a whole block we can avoid a copy. Introduce dm_{hook,unhook}_bio to simplify saving and restoring bio fields (bi_private is now used by overwrite). Switch writethrough support over to using these helpers too. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:48 -04:00
block: Abstract out bvec iterator Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-10-11 15:44:27 -07:00
dm cache: promotion optimisation for writes If a write block triggers promotion and covers a whole block we can avoid a copy. Introduce dm_{hook,unhook}_bio to simplify saving and restoring bio fields (bi_private is now used by overwrite). Switch writethrough support over to using these helpers too. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:48 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm cache: fix use after freeing migrations Both free_io_migration() and issue_discard() dereference a migration that was just freed. Fix those by saving off the migrations's cache object before freeing the migration. Also cleanup needless mg->cache dereferences now that the cache object is available directly. Fixes: e44b6a5a3c ("dm cache: move wake_waker() from free_migrations() to where it is needed") Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-09-01 11:38:19 +01:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm cache: fix use after freeing migrations Both free_io_migration() and issue_discard() dereference a migration that was just freed. Fix those by saving off the migrations's cache object before freeing the migration. Also cleanup needless mg->cache dereferences now that the cache object is available directly. Fixes: e44b6a5a3c ("dm cache: move wake_waker() from free_migrations() to where it is needed") Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-09-01 11:38:19 +01:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm cache: fix use after freeing migrations Both free_io_migration() and issue_discard() dereference a migration that was just freed. Fix those by saving off the migrations's cache object before freeing the migration. Also cleanup needless mg->cache dereferences now that the cache object is available directly. Fixes: e44b6a5a3c ("dm cache: move wake_waker() from free_migrations() to where it is needed") Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-09-01 11:38:19 +01:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
block: add a bi_error field to struct bio Currently we have two different ways to signal an I/O error on a BIO: (1) by clearing the BIO_UPTODATE flag (2) by returning a Linux errno value to the bi_end_io callback The first one has the drawback of only communicating a single possible error (-EIO), and the second one has the drawback of not beeing persistent when bios are queued up, and are not passed along from child to parent bio in the ever more popular chaining scenario. Having both mechanisms available has the additional drawback of utterly confusing driver authors and introducing bugs where various I/O submitters only deal with one of them, and the others have to add boilerplate code to deal with both kinds of error returns. So add a new bi_error field to store an errno value directly in struct bio and remove the existing mechanisms to clean all this up. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-07-20 15:29:37 +02:00
dm cache: fix use after freeing migrations Both free_io_migration() and issue_discard() dereference a migration that was just freed. Fix those by saving off the migrations's cache object before freeing the migration. Also cleanup needless mg->cache dereferences now that the cache object is available directly. Fixes: e44b6a5a3c ("dm cache: move wake_waker() from free_migrations() to where it is needed") Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-09-01 11:38:19 +01:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm cache: fix use after freeing migrations Both free_io_migration() and issue_discard() dereference a migration that was just freed. Fix those by saving off the migrations's cache object before freeing the migration. Also cleanup needless mg->cache dereferences now that the cache object is available directly. Fixes: e44b6a5a3c ("dm cache: move wake_waker() from free_migrations() to where it is needed") Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-09-01 11:38:19 +01:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: promotion optimisation for writes If a write block triggers promotion and covers a whole block we can avoid a copy. Introduce dm_{hook,unhook}_bio to simplify saving and restoring bio fields (bi_private is now used by overwrite). Switch writethrough support over to using these helpers too. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:48 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: only use overwrite optimisation for promotion when in writeback mode Overwrite causes the cache block and origin blocks to diverge, which is only allowed in writeback mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2014-11-27 12:21:08 +00:00
dm cache: promotion optimisation for writes If a write block triggers promotion and covers a whole block we can avoid a copy. Introduce dm_{hook,unhook}_bio to simplify saving and restoring bio fields (bi_private is now used by overwrite). Switch writethrough support over to using these helpers too. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:48 -04:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: simplify deferred set reference count increments Factor out inc_and_issue and inc_ds helpers to simplify deferred set reference count increments. Also cleanup cache_map to consistently call cell_defer and inc_ds when the bio is DM_MAPIO_REMAPPED. No functional change. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-05-13 16:18:38 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: promotion optimisation for writes If a write block triggers promotion and covers a whole block we can avoid a copy. Introduce dm_{hook,unhook}_bio to simplify saving and restoring bio fields (bi_private is now used by overwrite). Switch writethrough support over to using these helpers too. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:48 -04:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: promotion optimisation for writes If a write block triggers promotion and covers a whole block we can avoid a copy. Introduce dm_{hook,unhook}_bio to simplify saving and restoring bio fields (bi_private is now used by overwrite). Switch writethrough support over to using these helpers too. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:48 -04:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: promotion optimisation for writes If a write block triggers promotion and covers a whole block we can avoid a copy. Introduce dm_{hook,unhook}_bio to simplify saving and restoring bio fields (bi_private is now used by overwrite). Switch writethrough support over to using these helpers too. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:48 -04:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: reduce bio front_pad size in writeback mode A recent patch to fix the dm cache target's writethrough mode extended the bio's front_pad to include a 1056-byte struct dm_bio_details. Writeback mode doesn't need this, so this patch reduces the per_bio_data_size to 16 bytes in this case instead of 1096. The dm_bio_details structure was added in "dm cache: fix writes to cache device in writethrough mode" which fixed commit e2e74d617e ("dm cache: fix race in writethrough implementation"). In writeback mode we avoid allocating the writethrough-specific members of the per_bio_data structure (the dm_bio_details structure included). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-04-05 15:36:34 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
block: Abstract out bvec iterator Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-10-11 15:44:27 -07:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: simplify deferred set reference count increments Factor out inc_and_issue and inc_ds helpers to simplify deferred set reference count increments. Also cleanup cache_map to consistently call cell_defer and inc_ds when the bio is DM_MAPIO_REMAPPED. No functional change. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-05-13 16:18:38 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
block: add a bi_error field to struct bio Currently we have two different ways to signal an I/O error on a BIO: (1) by clearing the BIO_UPTODATE flag (2) by returning a Linux errno value to the bi_end_io callback The first one has the drawback of only communicating a single possible error (-EIO), and the second one has the drawback of not beeing persistent when bios are queued up, and are not passed along from child to parent bio in the ever more popular chaining scenario. Having both mechanisms available has the additional drawback of utterly confusing driver authors and introducing bugs where various I/O submitters only deal with one of them, and the others have to add boilerplate code to deal with both kinds of error returns. So add a new bi_error field to store an errno value directly in struct bio and remove the existing mechanisms to clean all this up. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-07-20 15:29:37 +02:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix race when issuing a POLICY_REPLACE operation There is a race between a policy deciding to replace a cache entry, the core target writing back any dirty data from this block, and other IO threads doing IO to the same block. This sort of problem is avoided most of the time by the core target grabbing a bio prison cell before making the request to the policy. But for a demotion the core target doesn't know which block will be demoted, so can't do this in advance. Fix this demotion race by introducing a callback to the policy interface that allows the policy to grab the cell on behalf of the core target. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-05-20 10:30:32 +01:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm cache: fix leaking of deferred bio prison cells There were two cases where dm_cell_visit_release() was being called, which removes the cell from the prison's rbtree, but the callers didn't also return the cell to the mempool. Fix this by having them call free_prison_cell(). This leak manifested as the 'kmalloc-96' slab growing until OOM. Fixes: 651f5fa2a3 ("dm cache: defer whole cells") Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org # 4.1+
2015-08-31 18:20:08 +01:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm cache: fix leaking of deferred bio prison cells There were two cases where dm_cell_visit_release() was being called, which removes the cell from the prison's rbtree, but the callers didn't also return the cell to the mempool. Fix this by having them call free_prison_cell(). This leak manifested as the 'kmalloc-96' slab growing until OOM. Fixes: 651f5fa2a3 ("dm cache: defer whole cells") Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org # 4.1+
2015-08-31 18:20:08 +01:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm cache: fix race when issuing a POLICY_REPLACE operation There is a race between a policy deciding to replace a cache entry, the core target writing back any dirty data from this block, and other IO threads doing IO to the same block. This sort of problem is avoided most of the time by the core target grabbing a bio prison cell before making the request to the policy. But for a demotion the core target doesn't know which block will be demoted, so can't do this in advance. Fix this demotion race by introducing a callback to the policy interface that allows the policy to grab the cell on behalf of the core target. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-05-20 10:30:32 +01:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm cache: boost promotion of blocks that will be overwritten When considering whether to move a block to the cache we already give preferential treatment to discarded blocks, since they are cheap to promote (no read of the origin required since the data is junk). The same is true of blocks that are about to be completely overwritten, so we likewise boost their promotion chances. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:29:58 +01:00
dm cache: fix race when issuing a POLICY_REPLACE operation There is a race between a policy deciding to replace a cache entry, the core target writing back any dirty data from this block, and other IO threads doing IO to the same block. This sort of problem is avoided most of the time by the core target grabbing a bio prison cell before making the request to the policy. But for a demotion the core target doesn't know which block will be demoted, so can't do this in advance. Fix this demotion race by introducing a callback to the policy interface that allows the policy to grab the cell on behalf of the core target. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-05-20 10:30:32 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: boost promotion of blocks that will be overwritten When considering whether to move a block to the cache we already give preferential treatment to discarded blocks, since they are cheap to promote (no read of the origin required since the data is junk). The same is true of blocks that are about to be completely overwritten, so we likewise boost their promotion chances. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:29:58 +01:00
dm cache: fix a harmless race when working out if a block is discarded It is more correct to hold the cell before checking the discard state. These flags are only used as hints to the policy so this change will have negligable effect. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-25 13:14:57 +00:00
dm cache: fix race when issuing a POLICY_REPLACE operation There is a race between a policy deciding to replace a cache entry, the core target writing back any dirty data from this block, and other IO threads doing IO to the same block. This sort of problem is avoided most of the time by the core target grabbing a bio prison cell before making the request to the policy. But for a demotion the core target doesn't know which block will be demoted, so can't do this in advance. Fix this demotion race by introducing a callback to the policy interface that allows the policy to grab the cell on behalf of the core target. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-05-20 10:30:32 +01:00
dm cache: boost promotion of blocks that will be overwritten When considering whether to move a block to the cache we already give preferential treatment to discarded blocks, since they are cheap to promote (no read of the origin required since the data is junk). The same is true of blocks that are about to be completely overwritten, so we likewise boost their promotion chances. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:29:58 +01:00
dm cache: fix race when issuing a POLICY_REPLACE operation There is a race between a policy deciding to replace a cache entry, the core target writing back any dirty data from this block, and other IO threads doing IO to the same block. This sort of problem is avoided most of the time by the core target grabbing a bio prison cell before making the request to the policy. But for a demotion the core target doesn't know which block will be demoted, so can't do this in advance. Fix this demotion race by introducing a callback to the policy interface that allows the policy to grab the cell on behalf of the core target. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-05-20 10:30:32 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm cache: simplify deferred set reference count increments Factor out inc_and_issue and inc_ds helpers to simplify deferred set reference count increments. Also cleanup cache_map to consistently call cell_defer and inc_ds when the bio is DM_MAPIO_REMAPPED. No functional change. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-05-13 16:18:38 +01:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm cache: simplify deferred set reference count increments Factor out inc_and_issue and inc_ds helpers to simplify deferred set reference count increments. Also cleanup cache_map to consistently call cell_defer and inc_ds when the bio is DM_MAPIO_REMAPPED. No functional change. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-05-13 16:18:38 +01:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm cache: simplify deferred set reference count increments Factor out inc_and_issue and inc_ds helpers to simplify deferred set reference count increments. Also cleanup cache_map to consistently call cell_defer and inc_ds when the bio is DM_MAPIO_REMAPPED. No functional change. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-05-13 16:18:38 +01:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix race when issuing a POLICY_REPLACE operation There is a race between a policy deciding to replace a cache entry, the core target writing back any dirty data from this block, and other IO threads doing IO to the same block. This sort of problem is avoided most of the time by the core target grabbing a bio prison cell before making the request to the policy. But for a demotion the core target doesn't know which block will be demoted, so can't do this in advance. Fix this demotion race by introducing a callback to the policy interface that allows the policy to grab the cell on behalf of the core target. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-05-20 10:30:32 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: optimize commit_if_needed Check commit_requested flag _before_ calling dm_cache_changed_this_transaction() superfluously. Also, be sure to set last_commit_jiffies _after_ dm_cache_commit() completes. Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-14 17:24:43 +02:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: optimize commit_if_needed Check commit_requested flag _before_ calling dm_cache_changed_this_transaction() superfluously. Also, be sure to set last_commit_jiffies _after_ dm_cache_commit() completes. Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-14 17:24:43 +02:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: optimize commit_if_needed Check commit_requested flag _before_ calling dm_cache_changed_this_transaction() superfluously. Also, be sure to set last_commit_jiffies _after_ dm_cache_commit() completes. Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-14 17:24:43 +02:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: avoid calls to prealloc_free_structs() if possible If no work was performed then prealloc_data_structs() wasn't ever called so there isn't any need to call prealloc_free_structs(). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-07-16 21:48:55 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix device destroy hang due to improper prealloc_used accounting Commit 665022d72f9 ("dm cache: avoid calls to prealloc_free_structs() if possible") introduced a regression that caused the removal of a DM cache device to hang in cache_postsuspend()'s call to wait_for_migrations() with the following stack trace: [<ffffffff81651457>] schedule+0x37/0x80 [<ffffffffa041e21b>] cache_postsuspend+0xbb/0x470 [dm_cache] [<ffffffff810ba970>] ? prepare_to_wait_event+0xf0/0xf0 [<ffffffffa0006f77>] dm_table_postsuspend_targets+0x47/0x60 [dm_mod] [<ffffffffa0001eb5>] __dm_destroy+0x215/0x250 [dm_mod] [<ffffffffa0004113>] dm_destroy+0x13/0x20 [dm_mod] [<ffffffffa00098cd>] dev_remove+0x10d/0x170 [dm_mod] [<ffffffffa00097c0>] ? dev_suspend+0x240/0x240 [dm_mod] [<ffffffffa0009f85>] ctl_ioctl+0x255/0x4d0 [dm_mod] [<ffffffff8127ac00>] ? SYSC_semtimedop+0x280/0xe10 [<ffffffffa000a213>] dm_ctl_ioctl+0x13/0x20 [dm_mod] [<ffffffff811fd432>] do_vfs_ioctl+0x2d2/0x4b0 [<ffffffff81117d5f>] ? __audit_syscall_entry+0xaf/0x100 [<ffffffff81022636>] ? do_audit_syscall_entry+0x66/0x70 [<ffffffff811fd689>] SyS_ioctl+0x79/0x90 [<ffffffff81023e58>] ? syscall_trace_leave+0xb8/0x110 [<ffffffff81654f6e>] entry_SYSCALL_64_fastpath+0x12/0x71 Fix this by accounting for the call to prealloc_data_structs() immediately _before_ the call as opposed to after. This is needed because it is possible to break out of the control loop after the call to prealloc_data_structs() but before prealloc_used was set to true. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-07-29 13:48:23 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: avoid calls to prealloc_free_structs() if possible If no work was performed then prealloc_data_structs() wasn't ever called so there isn't any need to call prealloc_free_structs(). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-07-16 21:48:55 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm cache: avoid calls to prealloc_free_structs() if possible If no work was performed then prealloc_data_structs() wasn't ever called so there isn't any need to call prealloc_free_structs(). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-07-16 21:48:55 -04:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm cache: fix device destroy hang due to improper prealloc_used accounting Commit 665022d72f9 ("dm cache: avoid calls to prealloc_free_structs() if possible") introduced a regression that caused the removal of a DM cache device to hang in cache_postsuspend()'s call to wait_for_migrations() with the following stack trace: [<ffffffff81651457>] schedule+0x37/0x80 [<ffffffffa041e21b>] cache_postsuspend+0xbb/0x470 [dm_cache] [<ffffffff810ba970>] ? prepare_to_wait_event+0xf0/0xf0 [<ffffffffa0006f77>] dm_table_postsuspend_targets+0x47/0x60 [dm_mod] [<ffffffffa0001eb5>] __dm_destroy+0x215/0x250 [dm_mod] [<ffffffffa0004113>] dm_destroy+0x13/0x20 [dm_mod] [<ffffffffa00098cd>] dev_remove+0x10d/0x170 [dm_mod] [<ffffffffa00097c0>] ? dev_suspend+0x240/0x240 [dm_mod] [<ffffffffa0009f85>] ctl_ioctl+0x255/0x4d0 [dm_mod] [<ffffffff8127ac00>] ? SYSC_semtimedop+0x280/0xe10 [<ffffffffa000a213>] dm_ctl_ioctl+0x13/0x20 [dm_mod] [<ffffffff811fd432>] do_vfs_ioctl+0x2d2/0x4b0 [<ffffffff81117d5f>] ? __audit_syscall_entry+0xaf/0x100 [<ffffffff81022636>] ? do_audit_syscall_entry+0x66/0x70 [<ffffffff811fd689>] SyS_ioctl+0x79/0x90 [<ffffffff81023e58>] ? syscall_trace_leave+0xb8/0x110 [<ffffffff81654f6e>] entry_SYSCALL_64_fastpath+0x12/0x71 Fix this by accounting for the call to prealloc_data_structs() immediately _before_ the call as opposed to after. This is needed because it is possible to break out of the control loop after the call to prealloc_data_structs() but before prealloc_used was set to true. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-07-29 13:48:23 -04:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm cache: avoid calls to prealloc_free_structs() if possible If no work was performed then prealloc_data_structs() wasn't ever called so there isn't any need to call prealloc_free_structs(). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-07-16 21:48:55 -04:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: simplify deferred set reference count increments Factor out inc_and_issue and inc_ds helpers to simplify deferred set reference count increments. Also cleanup cache_map to consistently call cell_defer and inc_ds when the bio is DM_MAPIO_REMAPPED. No functional change. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-05-13 16:18:38 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: track IO to the origin device using io_tracker Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:18:01 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix race in writethrough implementation We have found a race in the optimisation used in the dm cache writethrough implementation. Currently, dm core sends the cache target two bios, one for the origin device and one for the cache device and these are processed in parallel. This patch avoids the race by changing the code back to a simpler (slower) implementation which processes the two writes in series, one after the other, until we can develop a complete fix for the problem. When the cache is in writethrough mode it needs to send WRITE bios to both the origin and cache devices. Previously we've been implementing this by having dm core query the cache target on every write to find out how many copies of the bio it wants. The cache will ask for two bios if the block is in the cache, and one otherwise. Then main problem with this is it's racey. At the time this check is made the bio hasn't yet been submitted and so isn't being taken into account when quiescing a block for migration (promotion or demotion). This means a single bio may be submitted when two were needed because the block has since been promoted to the cache (catastrophic), or two bios where only one is needed (harmless). I really don't want to start entering bios into the quiescing system (deferred_set) in the get_num_write_bios callback. Instead this patch simplifies things; only one bio is submitted by the core, this is first written to the origin and then the cache device in series. Obviously this will have a latency impact. deferred_writethrough_bios is introduced to record bios that must be later issued to the cache device from the worker thread. This deferred submission, after the origin bio completes, is required given that we're in interrupt context (writethrough_endio). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-20 17:21:27 +00:00
dm cache: simplify deferred set reference count increments Factor out inc_and_issue and inc_ds helpers to simplify deferred set reference count increments. Also cleanup cache_map to consistently call cell_defer and inc_ds when the bio is DM_MAPIO_REMAPPED. No functional change. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-05-13 16:18:38 +01:00
dm cache: fix race in writethrough implementation We have found a race in the optimisation used in the dm cache writethrough implementation. Currently, dm core sends the cache target two bios, one for the origin device and one for the cache device and these are processed in parallel. This patch avoids the race by changing the code back to a simpler (slower) implementation which processes the two writes in series, one after the other, until we can develop a complete fix for the problem. When the cache is in writethrough mode it needs to send WRITE bios to both the origin and cache devices. Previously we've been implementing this by having dm core query the cache target on every write to find out how many copies of the bio it wants. The cache will ask for two bios if the block is in the cache, and one otherwise. Then main problem with this is it's racey. At the time this check is made the bio hasn't yet been submitted and so isn't being taken into account when quiescing a block for migration (promotion or demotion). This means a single bio may be submitted when two were needed because the block has since been promoted to the cache (catastrophic), or two bios where only one is needed (harmless). I really don't want to start entering bios into the quiescing system (deferred_set) in the get_num_write_bios callback. Instead this patch simplifies things; only one bio is submitted by the core, this is first written to the origin and then the cache device in series. Obviously this will have a latency impact. deferred_writethrough_bios is introduced to record bios that must be later issued to the cache device from the worker thread. This deferred submission, after the origin bio completes, is required given that we're in interrupt context (writethrough_endio). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-20 17:21:27 +00:00
dm cache: track IO to the origin device using io_tracker Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:18:01 +01:00
dm cache: fix race in writethrough implementation We have found a race in the optimisation used in the dm cache writethrough implementation. Currently, dm core sends the cache target two bios, one for the origin device and one for the cache device and these are processed in parallel. This patch avoids the race by changing the code back to a simpler (slower) implementation which processes the two writes in series, one after the other, until we can develop a complete fix for the problem. When the cache is in writethrough mode it needs to send WRITE bios to both the origin and cache devices. Previously we've been implementing this by having dm core query the cache target on every write to find out how many copies of the bio it wants. The cache will ask for two bios if the block is in the cache, and one otherwise. Then main problem with this is it's racey. At the time this check is made the bio hasn't yet been submitted and so isn't being taken into account when quiescing a block for migration (promotion or demotion). This means a single bio may be submitted when two were needed because the block has since been promoted to the cache (catastrophic), or two bios where only one is needed (harmless). I really don't want to start entering bios into the quiescing system (deferred_set) in the get_num_write_bios callback. Instead this patch simplifies things; only one bio is submitted by the core, this is first written to the origin and then the cache device in series. Obviously this will have a latency impact. deferred_writethrough_bios is introduced to record bios that must be later issued to the cache device from the worker thread. This deferred submission, after the origin bio completes, is required given that we're in interrupt context (writethrough_endio). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-20 17:21:27 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: avoid calls to prealloc_free_structs() if possible If no work was performed then prealloc_data_structs() wasn't ever called so there isn't any need to call prealloc_free_structs(). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-07-16 21:48:55 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: pass a new 'critical' flag to the policies when requesting writeback work We only allow non critical writeback if the origin is idle. It is up to the policy to decide what writeback work is critical. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:20:09 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: avoid preallocation if no work in writeback_some_dirty_blocks() Refactor writeback_some_dirty_blocks() to avoid prealloc_data_structs() if the policy doesn't have any dirty blocks ready for writeback. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-07-16 21:26:10 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix device destroy hang due to improper prealloc_used accounting Commit 665022d72f9 ("dm cache: avoid calls to prealloc_free_structs() if possible") introduced a regression that caused the removal of a DM cache device to hang in cache_postsuspend()'s call to wait_for_migrations() with the following stack trace: [<ffffffff81651457>] schedule+0x37/0x80 [<ffffffffa041e21b>] cache_postsuspend+0xbb/0x470 [dm_cache] [<ffffffff810ba970>] ? prepare_to_wait_event+0xf0/0xf0 [<ffffffffa0006f77>] dm_table_postsuspend_targets+0x47/0x60 [dm_mod] [<ffffffffa0001eb5>] __dm_destroy+0x215/0x250 [dm_mod] [<ffffffffa0004113>] dm_destroy+0x13/0x20 [dm_mod] [<ffffffffa00098cd>] dev_remove+0x10d/0x170 [dm_mod] [<ffffffffa00097c0>] ? dev_suspend+0x240/0x240 [dm_mod] [<ffffffffa0009f85>] ctl_ioctl+0x255/0x4d0 [dm_mod] [<ffffffff8127ac00>] ? SYSC_semtimedop+0x280/0xe10 [<ffffffffa000a213>] dm_ctl_ioctl+0x13/0x20 [dm_mod] [<ffffffff811fd432>] do_vfs_ioctl+0x2d2/0x4b0 [<ffffffff81117d5f>] ? __audit_syscall_entry+0xaf/0x100 [<ffffffff81022636>] ? do_audit_syscall_entry+0x66/0x70 [<ffffffff811fd689>] SyS_ioctl+0x79/0x90 [<ffffffff81023e58>] ? syscall_trace_leave+0xb8/0x110 [<ffffffff81654f6e>] entry_SYSCALL_64_fastpath+0x12/0x71 Fix this by accounting for the call to prealloc_data_structs() immediately _before_ the call as opposed to after. This is needed because it is possible to break out of the control loop after the call to prealloc_data_structs() but before prealloc_used was set to true. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-07-29 13:48:23 -04:00
dm cache: avoid preallocation if no work in writeback_some_dirty_blocks() Refactor writeback_some_dirty_blocks() to avoid prealloc_data_structs() if the policy doesn't have any dirty blocks ready for writeback. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-07-16 21:26:10 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: avoid calls to prealloc_free_structs() if possible If no work was performed then prealloc_data_structs() wasn't ever called so there isn't any need to call prealloc_free_structs(). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-07-16 21:48:55 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve efficiency of quiescing flag management Make the quiescing flag an atomic_t and stop protecting it with a spin lock. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-30 17:29:30 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix a race condition between queuing new migrations and quiescing for a shutdown The code that was trying to do this was inadequate. The postsuspend method (in ioctl context), needs to wait for the worker thread to acknowledge the request to quiesce. Otherwise the migration count may drop to zero temporarily before the worker thread realises we're quiescing. In this case the target will be taken down, but the worker thread may have issued a new migration, which will cause an oops when it completes. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org # 3.9+
2013-10-30 17:11:58 +00:00
dm cache: improve efficiency of quiescing flag management Make the quiescing flag an atomic_t and stop protecting it with a spin lock. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-30 17:29:30 +00:00
dm cache: fix a race condition between queuing new migrations and quiescing for a shutdown The code that was trying to do this was inadequate. The postsuspend method (in ioctl context), needs to wait for the worker thread to acknowledge the request to quiesce. Otherwise the migration count may drop to zero temporarily before the worker thread realises we're quiescing. In this case the target will be taken down, but the worker thread may have issued a new migration, which will cause an oops when it completes. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org # 3.9+
2013-10-30 17:11:58 +00:00
dm cache: improve efficiency of quiescing flag management Make the quiescing flag an atomic_t and stop protecting it with a spin lock. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-30 17:29:30 +00:00
dm cache: fix a race condition between queuing new migrations and quiescing for a shutdown The code that was trying to do this was inadequate. The postsuspend method (in ioctl context), needs to wait for the worker thread to acknowledge the request to quiesce. Otherwise the migration count may drop to zero temporarily before the worker thread realises we're quiescing. In this case the target will be taken down, but the worker thread may have issued a new migration, which will cause an oops when it completes. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org # 3.9+
2013-10-30 17:11:58 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
block: add a bi_error field to struct bio Currently we have two different ways to signal an I/O error on a BIO: (1) by clearing the BIO_UPTODATE flag (2) by returning a Linux errno value to the bi_end_io callback The first one has the drawback of only communicating a single possible error (-EIO), and the second one has the drawback of not beeing persistent when bios are queued up, and are not passed along from child to parent bio in the ever more popular chaining scenario. Having both mechanisms available has the additional drawback of utterly confusing driver authors and introducing bugs where various I/O submitters only deal with one of them, and the others have to add boilerplate code to deal with both kinds of error returns. So add a new bi_error field to store an errno value directly in struct bio and remove the existing mechanisms to clean all this up. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-07-20 15:29:37 +02:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix race in writethrough implementation We have found a race in the optimisation used in the dm cache writethrough implementation. Currently, dm core sends the cache target two bios, one for the origin device and one for the cache device and these are processed in parallel. This patch avoids the race by changing the code back to a simpler (slower) implementation which processes the two writes in series, one after the other, until we can develop a complete fix for the problem. When the cache is in writethrough mode it needs to send WRITE bios to both the origin and cache devices. Previously we've been implementing this by having dm core query the cache target on every write to find out how many copies of the bio it wants. The cache will ask for two bios if the block is in the cache, and one otherwise. Then main problem with this is it's racey. At the time this check is made the bio hasn't yet been submitted and so isn't being taken into account when quiescing a block for migration (promotion or demotion). This means a single bio may be submitted when two were needed because the block has since been promoted to the cache (catastrophic), or two bios where only one is needed (harmless). I really don't want to start entering bios into the quiescing system (deferred_set) in the get_num_write_bios callback. Instead this patch simplifies things; only one bio is submitted by the core, this is first written to the origin and then the cache device in series. Obviously this will have a latency impact. deferred_writethrough_bios is introduced to record bios that must be later issued to the cache device from the worker thread. This deferred submission, after the origin bio completes, is required given that we're in interrupt context (writethrough_endio). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-20 17:21:27 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix a race condition between queuing new migrations and quiescing for a shutdown The code that was trying to do this was inadequate. The postsuspend method (in ioctl context), needs to wait for the worker thread to acknowledge the request to quiesce. Otherwise the migration count may drop to zero temporarily before the worker thread realises we're quiescing. In this case the target will be taken down, but the worker thread may have issued a new migration, which will cause an oops when it completes. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org # 3.9+
2013-10-30 17:11:58 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm cache: fix a race condition between queuing new migrations and quiescing for a shutdown The code that was trying to do this was inadequate. The postsuspend method (in ioctl context), needs to wait for the worker thread to acknowledge the request to quiesce. Otherwise the migration count may drop to zero temporarily before the worker thread realises we're quiescing. In this case the target will be taken down, but the worker thread may have issued a new migration, which will cause an oops when it completes. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org # 3.9+
2013-10-30 17:11:58 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fail migrations in the do_worker error path Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-06-24 15:36:58 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix a race condition between queuing new migrations and quiescing for a shutdown The code that was trying to do this was inadequate. The postsuspend method (in ioctl context), needs to wait for the worker thread to acknowledge the request to quiesce. Otherwise the migration count may drop to zero temporarily before the worker thread realises we're quiescing. In this case the target will be taken down, but the worker thread may have issued a new migration, which will cause an oops when it completes. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org # 3.9+
2013-10-30 17:11:58 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: age and write back cache entries even without active IO The policy tick() method is normally called from interrupt context. Both the mq and smq policies do some bottom half work for the tick method in their map functions. However if no IO is going through the cache, then that bottom half work doesn't occur. With these policies this means recently hit entries do not age and do not get written back as early as we'd like. Fix this by introducing a new 'can_block' parameter to the tick() method. When this is set the bottom half work occurs immediately. 'can_block' is set when the tick method is called every second by the core target (not in interrupt context). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 10:20:56 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm: drop NULL test before kmem_cache_destroy() and mempool_destroy() Remove DM's unneeded NULL tests before calling these destroy functions, now that they check for NULL, thanks to these v4.3 commits: 3942d2991 ("mm/slab_common: allow NULL cache pointer in kmem_cache_destroy()") 4e3ca3e03 ("mm/mempool: allow NULL `pool' pointer in mempool_destroy()") The semantic patch that makes this change is as follows: (http://coccinelle.lip6.fr/) // <smpl> @@ expression x; @@ -if (x != NULL) \(kmem_cache_destroy\|mempool_destroy\|dma_pool_destroy\)(x); // </smpl> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-09-13 14:15:05 +02:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add data block size limits to code and Documentation Place upper bound on the cache's data block size (1GB). Inform users that the data block size can't be any arbitrary number, i.e. its value must be between 32KB and 1GB. Also, it should be a multiple of 32KB. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2013-08-16 10:54:19 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add data block size limits to code and Documentation Place upper bound on the cache's data block size (1GB). Inform users that the data block size can't be any arbitrary number, i.e. its value must be between 32KB and 1GB. Also, it should be a multiple of 32KB. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2013-08-16 10:54:19 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add data block size limits to code and Documentation Place upper bound on the cache's data block size (1GB). Inform users that the data block size can't be any arbitrary number, i.e. its value must be between 32KB and 1GB. Also, it should be a multiple of 32KB. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2013-08-16 10:54:19 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add data block size limits to code and Documentation Place upper bound on the cache's data block size (1GB). Inform users that the data block size can't be any arbitrary number, i.e. its value must be between 32KB and 1GB. Also, it should be a multiple of 32KB. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2013-08-16 10:54:19 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: move config fns Move process_config_option() in dm-cache-target.c to make the next patch more readable. Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-05-10 14:37:21 +01:00
dm cache: set config value Share configuration option processing code between the dm cache ctr and message functions. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-05-10 14:37:21 +01:00
dm cache: move config fns Move process_config_option() in dm-cache-target.c to make the next patch more readable. Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-05-10 14:37:21 +01:00
dm cache: set config value Share configuration option processing code between the dm cache ctr and message functions. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-05-10 14:37:21 +01:00
dm cache: move config fns Move process_config_option() in dm-cache-target.c to make the next patch more readable. Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-05-10 14:37:21 +01:00
dm cache: set config value Share configuration option processing code between the dm cache ctr and message functions. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-05-10 14:37:21 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: set config value Share configuration option processing code between the dm cache ctr and message functions. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-05-10 14:37:21 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: return -EINVAL if the user specifies unknown cache policy Return -EINVAL when the specified cache policy is unknown rather than returning -ENOMEM. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-01 18:35:39 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: return -EINVAL if the user specifies unknown cache policy Return -EINVAL when the specified cache policy is unknown rather than returning -ENOMEM. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-01 18:35:39 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: return -EINVAL if the user specifies unknown cache policy Return -EINVAL when the specified cache policy is unknown rather than returning -ENOMEM. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-01 18:35:39 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: set config value Share configuration option processing code between the dm cache ctr and message functions. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-05-10 14:37:21 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: revert "prevent corruption caused by discard_block_size > cache_block_size" This reverts commit d132cc6d9e92424bb9d4fd35f5bd0e55d583f4be because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 14:38:01 +00:00
dm cache: discard block size must be a multiple of cache block size Otherwise the cache blocks may span two discard blocks, which we don't handle when doing the discard lookup. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-26 16:07:50 +00:00
dm cache: revert "prevent corruption caused by discard_block_size > cache_block_size" This reverts commit d132cc6d9e92424bb9d4fd35f5bd0e55d583f4be because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 14:38:01 +00:00
dm cache: discard block size must be a multiple of cache block size Otherwise the cache blocks may span two discard blocks, which we don't handle when doing the discard lookup. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-26 16:07:50 +00:00
dm cache: revert "prevent corruption caused by discard_block_size > cache_block_size" This reverts commit d132cc6d9e92424bb9d4fd35f5bd0e55d583f4be because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 14:38:01 +00:00
dm cache: emit a warning message if there are a lot of cache blocks Loading and saving millions of block mappings takes time. We may as well explain what's going on, and encourage people to use a larger cache block size. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-11 11:58:32 +00:00
dm cache: tune migration throttling Tune the dm cache migration throttling. i) Issue a tick every second, just in case there's no i/o going through. ii) Drop the migration threshold right down to something suitable for background work. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-05-10 14:37:16 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix some issues with the new discard range support Commit 7ae34e777 ("dm cache: improve discard support") needed to also: - discontinue having DM core split the discard bios on cache block boundaries - calculate the cache's discard_nr_blocks relative to the determined discard_block_size rather than using oblock_to_dblock() Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-24 14:05:16 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: replace memcpy with struct assignment Use struct assignment rather than memcpy in dm cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-05-10 14:37:18 +01:00
dm cache: reduce bio front_pad size in writeback mode A recent patch to fix the dm cache target's writethrough mode extended the bio's front_pad to include a 1056-byte struct dm_bio_details. Writeback mode doesn't need this, so this patch reduces the per_bio_data_size to 16 bytes in this case instead of 1096. The dm_bio_details structure was added in "dm cache: fix writes to cache device in writethrough mode" which fixed commit e2e74d617e ("dm cache: fix race in writethrough implementation"). In writeback mode we avoid allocating the writethrough-specific members of the per_bio_data structure (the dm_bio_details structure included). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-04-05 15:36:34 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: avoid 64 bit division on 32 bit Squash various 32bit link errors. >> on i386: >> drivers/built-in.o: In function `is_discarded_oblock': >> dm-cache-target.c:(.text+0x1ea28e): undefined reference to `__udivdi3' ... Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-20 17:21:25 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: avoid 64 bit division on 32 bit Squash various 32bit link errors. >> on i386: >> drivers/built-in.o: In function `is_discarded_oblock': >> dm-cache-target.c:(.text+0x1ea28e): undefined reference to `__udivdi3' ... Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-20 17:21:25 +00:00
dm cache: emit a warning message if there are a lot of cache blocks Loading and saving millions of block mappings takes time. We may as well explain what's going on, and encourage people to use a larger cache block size. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-11 11:58:32 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: emit a warning message if there are a lot of cache blocks Loading and saving millions of block mappings takes time. We may as well explain what's going on, and encourage people to use a larger cache block size. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-11 11:58:32 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: set config value Share configuration option processing code between the dm cache ctr and message functions. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-05-10 14:37:21 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: set config value Share configuration option processing code between the dm cache ctr and message functions. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-05-10 14:37:21 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix race in writethrough implementation We have found a race in the optimisation used in the dm cache writethrough implementation. Currently, dm core sends the cache target two bios, one for the origin device and one for the cache device and these are processed in parallel. This patch avoids the race by changing the code back to a simpler (slower) implementation which processes the two writes in series, one after the other, until we can develop a complete fix for the problem. When the cache is in writethrough mode it needs to send WRITE bios to both the origin and cache devices. Previously we've been implementing this by having dm core query the cache target on every write to find out how many copies of the bio it wants. The cache will ask for two bios if the block is in the cache, and one otherwise. Then main problem with this is it's racey. At the time this check is made the bio hasn't yet been submitted and so isn't being taken into account when quiescing a block for migration (promotion or demotion). This means a single bio may be submitted when two were needed because the block has since been promoted to the cache (catastrophic), or two bios where only one is needed (harmless). I really don't want to start entering bios into the quiescing system (deferred_set) in the get_num_write_bios callback. Instead this patch simplifies things; only one bio is submitted by the core, this is first written to the origin and then the cache device in series. Obviously this will have a latency impact. deferred_writethrough_bios is introduced to record bios that must be later issued to the cache device from the worker thread. This deferred submission, after the origin bio completes, is required given that we're in interrupt context (writethrough_endio). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-20 17:21:27 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-01-23 10:16:16 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix a race condition between queuing new migrations and quiescing for a shutdown The code that was trying to do this was inadequate. The postsuspend method (in ioctl context), needs to wait for the worker thread to acknowledge the request to quiesce. Otherwise the migration count may drop to zero temporarily before the worker thread realises we're quiescing. In this case the target will be taken down, but the worker thread may have issued a new migration, which will cause an oops when it completes. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org # 3.9+
2013-10-30 17:11:58 +00:00
dm cache: improve efficiency of quiescing flag management Make the quiescing flag an atomic_t and stop protecting it with a spin lock. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-30 17:29:30 +00:00
dm cache: fix a race condition between queuing new migrations and quiescing for a shutdown The code that was trying to do this was inadequate. The postsuspend method (in ioctl context), needs to wait for the worker thread to acknowledge the request to quiesce. Otherwise the migration count may drop to zero temporarily before the worker thread realises we're quiescing. In this case the target will be taken down, but the worker thread may have issued a new migration, which will cause an oops when it completes. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org # 3.9+
2013-10-30 17:11:58 +00:00
dm cache: fix error return code in cache_create Return -ENOMEM if memory allocation fails in cache_create instead of 0 (to avoid NULL pointer dereference). Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: stable@vger.kernel.org Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-05-10 14:37:14 +01:00
dm cache: fix race affecting dirty block count nr_dirty is updated without locking, causing it to drift so that it is non-zero (either a small positive integer, or a very large one when an underflow occurs) even when there are no actual dirty blocks. This was due to a race between the workqueue and map function accessing nr_dirty in parallel without proper protection. People were seeing under runs due to a race on increment/decrement of nr_dirty, see: https://lkml.org/lkml/2014/6/3/648 Fix this by using an atomic_t for nr_dirty. Reported-by: roma1390@gmail.com Signed-off-by: Anssi Hannula <anssi.hannula@iki.fi> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2014-08-01 11:55:47 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: revert "prevent corruption caused by discard_block_size > cache_block_size" This reverts commit d132cc6d9e92424bb9d4fd35f5bd0e55d583f4be because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 14:38:01 +00:00
dm cache: fix some issues with the new discard range support Commit 7ae34e777 ("dm cache: improve discard support") needed to also: - discontinue having DM core split the discard bios on cache block boundaries - calculate the cache's discard_nr_blocks relative to the determined discard_block_size rather than using oblock_to_dblock() Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-24 14:05:16 +00:00
dm cache: revert "remove remainder of distinct discard block size" This reverts commit 64ab346a360a4b15c28fb8531918d4a01f4eabd9 because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-07 14:47:07 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: revert "remove remainder of distinct discard block size" This reverts commit 64ab346a360a4b15c28fb8531918d4a01f4eabd9 because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-07 14:47:07 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm bio prison: switch to using a red black tree Previously it was using a fixed sized hash table. There are times when very many concurrent cells are held (such as when processing a very large discard). When this happens the hash table performance becomes very poor. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-10-06 16:30:06 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm cache: track IO to the origin device using io_tracker Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:18:01 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: detect cache_create failure Return error if cache_create() fails. A missing return check made cache_ctr continue even after an error in cache_create() resulting in the cache object being destroyed. So a simple failure like an odd number of cache policy config value arguments would result in an oops. Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-20 17:21:26 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: reduce bio front_pad size in writeback mode A recent patch to fix the dm cache target's writethrough mode extended the bio's front_pad to include a 1056-byte struct dm_bio_details. Writeback mode doesn't need this, so this patch reduces the per_bio_data_size to 16 bytes in this case instead of 1096. The dm_bio_details structure was added in "dm cache: fix writes to cache device in writethrough mode" which fixed commit e2e74d617e ("dm cache: fix race in writethrough implementation"). In writeback mode we avoid allocating the writethrough-specific members of the per_bio_data structure (the dm_bio_details structure included). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-04-05 15:36:34 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: boost promotion of blocks that will be overwritten When considering whether to move a block to the cache we already give preferential treatment to discarded blocks, since they are cheap to promote (no read of the origin required since the data is junk). The same is true of blocks that are about to be completely overwritten, so we likewise boost their promotion chances. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:29:58 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix access beyond end of origin device In order to avoid wasting cache space a partial block at the end of the origin device is not cached. Unfortunately, the check for such a partial block at the end of the origin device was flawed. Fix accesses beyond the end of the origin device that occured due to attempted promotion of an undetected partial block by: - initializing the per bio data struct to allow cache_end_io to work properly - recognizing access to the partial block at the end of the origin device - avoiding out of bounds access to the discard bitset Otherwise, users can experience errors like the following: attempt to access beyond end of device dm-5: rw=0, want=20971520, limit=20971456 ... device-mapper: cache: promotion failed; couldn't copy block Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2014-03-12 16:13:39 +01:00
dm cache: fix race when issuing a POLICY_REPLACE operation There is a race between a policy deciding to replace a cache entry, the core target writing back any dirty data from this block, and other IO threads doing IO to the same block. This sort of problem is avoided most of the time by the core target grabbing a bio prison cell before making the request to the policy. But for a demotion the core target doesn't know which block will be demoted, so can't do this in advance. Fix this demotion race by introducing a callback to the policy interface that allows the policy to grab the cell on behalf of the core target. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-05-20 10:30:32 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix access beyond end of origin device In order to avoid wasting cache space a partial block at the end of the origin device is not cached. Unfortunately, the check for such a partial block at the end of the origin device was flawed. Fix accesses beyond the end of the origin device that occured due to attempted promotion of an undetected partial block by: - initializing the per bio data struct to allow cache_end_io to work properly - recognizing access to the partial block at the end of the origin device - avoiding out of bounds access to the discard bitset Otherwise, users can experience errors like the following: attempt to access beyond end of device dm-5: rw=0, want=20971520, limit=20971456 ... device-mapper: cache: promotion failed; couldn't copy block Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2014-03-12 16:13:39 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix access beyond end of origin device In order to avoid wasting cache space a partial block at the end of the origin device is not cached. Unfortunately, the check for such a partial block at the end of the origin device was flawed. Fix accesses beyond the end of the origin device that occured due to attempted promotion of an undetected partial block by: - initializing the per bio data struct to allow cache_end_io to work properly - recognizing access to the partial block at the end of the origin device - avoiding out of bounds access to the discard bitset Otherwise, users can experience errors like the following: attempt to access beyond end of device dm-5: rw=0, want=20971520, limit=20971456 ... device-mapper: cache: promotion failed; couldn't copy block Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2014-03-12 16:13:39 +01:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: boost promotion of blocks that will be overwritten When considering whether to move a block to the cache we already give preferential treatment to discarded blocks, since they are cheap to promote (no read of the origin required since the data is junk). The same is true of blocks that are about to be completely overwritten, so we likewise boost their promotion chances. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:29:58 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: boost promotion of blocks that will be overwritten When considering whether to move a block to the cache we already give preferential treatment to discarded blocks, since they are cheap to promote (no read of the origin required since the data is junk). The same is true of blocks that are about to be completely overwritten, so we likewise boost their promotion chances. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:29:58 +01:00
dm cache: fix race when issuing a POLICY_REPLACE operation There is a race between a policy deciding to replace a cache entry, the core target writing back any dirty data from this block, and other IO threads doing IO to the same block. This sort of problem is avoided most of the time by the core target grabbing a bio prison cell before making the request to the policy. But for a demotion the core target doesn't know which block will be demoted, so can't do this in advance. Fix this demotion race by introducing a callback to the policy interface that allows the policy to grab the cell on behalf of the core target. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2015-05-20 10:30:32 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
block: add a bi_error field to struct bio Currently we have two different ways to signal an I/O error on a BIO: (1) by clearing the BIO_UPTODATE flag (2) by returning a Linux errno value to the bi_end_io callback The first one has the drawback of only communicating a single possible error (-EIO), and the second one has the drawback of not beeing persistent when bios are queued up, and are not passed along from child to parent bio in the ever more popular chaining scenario. Having both mechanisms available has the additional drawback of utterly confusing driver authors and introducing bugs where various I/O submitters only deal with one of them, and the others have to add boilerplate code to deal with both kinds of error returns. So add a new bi_error field to store an errno value directly in struct bio and remove the existing mechanisms to clean all this up. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-07-20 15:29:37 +02:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm cache: simplify deferred set reference count increments Factor out inc_and_issue and inc_ds helpers to simplify deferred set reference count increments. Also cleanup cache_map to consistently call cell_defer and inc_ds when the bio is DM_MAPIO_REMAPPED. No functional change. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-05-13 16:18:38 +01:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: reduce bio front_pad size in writeback mode A recent patch to fix the dm cache target's writethrough mode extended the bio's front_pad to include a 1056-byte struct dm_bio_details. Writeback mode doesn't need this, so this patch reduces the per_bio_data_size to 16 bytes in this case instead of 1096. The dm_bio_details structure was added in "dm cache: fix writes to cache device in writethrough mode" which fixed commit e2e74d617e ("dm cache: fix race in writethrough implementation"). In writeback mode we avoid allocating the writethrough-specific members of the per_bio_data structure (the dm_bio_details structure included). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-04-05 15:36:34 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: age and write back cache entries even without active IO The policy tick() method is normally called from interrupt context. Both the mq and smq policies do some bottom half work for the tick method in their map functions. However if no IO is going through the cache, then that bottom half work doesn't occur. With these policies this means recently hit entries do not age and do not get written back as early as we'd like. Fix this by introducing a new 'can_block' parameter to the tick() method. When this is set the bottom half work occurs immediately. 'can_block' is set when the tick method is called every second by the core target (not in interrupt context). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 10:20:56 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: track IO to the origin device using io_tracker Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:18:01 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm cache: revert "remove remainder of distinct discard block size" This reverts commit 64ab346a360a4b15c28fb8531918d4a01f4eabd9 because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-07 14:47:07 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: revert "remove remainder of distinct discard block size" This reverts commit 64ab346a360a4b15c28fb8531918d4a01f4eabd9 because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-07 14:47:07 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: defer whole cells Currently individual bios are deferred to the worker thread if they cannot be processed immediately (eg, a block is in the process of being moved to the fast device). This patch passes whole cells across to the worker. This saves reaquiring the cell, and also collects bios destined for the same block together, which allows them to be mapped with a single look up to the policy. This reduces the overhead of using dm-cache. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-15 15:26:08 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: when reloading a discard bitset allow for a different discard block size The discard block size can change if the origin changes size or if an old DM cache is upgraded from using a discard block size that was equal to cache block size. To fix this an extent of discarded blocks is established for the purpose of translating the old discard block size to the new in-core discard block size and set bits. The old (potentially huge) discard bitset is left ondisk until it is re-written using the new in-core information on the next successful DM cache shutdown. Fixes: 7ae34e777896 ("dm cache: improve discard support") Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-24 14:06:22 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: revert "remove remainder of distinct discard block size" This reverts commit 64ab346a360a4b15c28fb8531918d4a01f4eabd9 because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-07 14:47:07 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: when reloading a discard bitset allow for a different discard block size The discard block size can change if the origin changes size or if an old DM cache is upgraded from using a discard block size that was equal to cache block size. To fix this an extent of discarded blocks is established for the purpose of translating the old discard block size to the new in-core discard block size and set bits. The old (potentially huge) discard bitset is left ondisk until it is re-written using the new in-core information on the next successful DM cache shutdown. Fixes: 7ae34e777896 ("dm cache: improve discard support") Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-24 14:06:22 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: when reloading a discard bitset allow for a different discard block size The discard block size can change if the origin changes size or if an old DM cache is upgraded from using a discard block size that was equal to cache block size. To fix this an extent of discarded blocks is established for the purpose of translating the old discard block size to the new in-core discard block size and set bits. The old (potentially huge) discard bitset is left ondisk until it is re-written using the new in-core information on the next successful DM cache shutdown. Fixes: 7ae34e777896 ("dm cache: improve discard support") Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-24 14:06:22 +00:00
dm cache: revert "remove remainder of distinct discard block size" This reverts commit 64ab346a360a4b15c28fb8531918d4a01f4eabd9 because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-07 14:47:07 +00:00
dm cache: when reloading a discard bitset allow for a different discard block size The discard block size can change if the origin changes size or if an old DM cache is upgraded from using a discard block size that was equal to cache block size. To fix this an extent of discarded blocks is established for the purpose of translating the old discard block size to the new in-core discard block size and set bits. The old (potentially huge) discard bitset is left ondisk until it is re-written using the new in-core information on the next successful DM cache shutdown. Fixes: 7ae34e777896 ("dm cache: improve discard support") Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-24 14:06:22 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: cache shrinking support Allow a cache to shrink if the blocks being removed from the cache are not dirty. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:49 -04:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: cache shrinking support Allow a cache to shrink if the blocks being removed from the cache are not dirty. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:49 -04:00
dm cache: actually resize cache Commit f494a9c6b1b6dd9a9f21bbb75d9210d478eeb498 ("dm cache: cache shrinking support") broke cache resizing support. dm_cache_resize() is called with cache->cache_size before it gets updated to new_size, so it is a no-op. But the dm-cache superblock is updated with the new_size even though the backing dm-array is not resized. Fix this by passing the new_size to dm_cache_resize(). Signed-off-by: Vincent Pelletier <plr.vincent@gmail.com> Acked-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-30 12:58:42 +01:00
dm cache: cache shrinking support Allow a cache to shrink if the blocks being removed from the cache are not dirty. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:49 -04:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm cache: cache shrinking support Allow a cache to shrink if the blocks being removed from the cache are not dirty. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:49 -04:00
dm cache: emit a warning message if there are a lot of cache blocks Loading and saving millions of block mappings takes time. We may as well explain what's going on, and encourage people to use a larger cache block size. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-11 11:58:32 +00:00
dm cache: cache shrinking support Allow a cache to shrink if the blocks being removed from the cache are not dirty. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:49 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: cache shrinking support Allow a cache to shrink if the blocks being removed from the cache are not dirty. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:49 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: cache shrinking support Allow a cache to shrink if the blocks being removed from the cache are not dirty. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:49 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: cache shrinking support Allow a cache to shrink if the blocks being removed from the cache are not dirty. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-31 13:55:49 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: policy ignore hints if generated by different version When reading the dm cache metadata from disk, ignore the policy hints unless they were generated by the same major version number of the same policy module. The hints are considered to be private data belonging to the specific module that generated them and there is no requirement for them to make sense to different versions of the policy that generated them. Policy modules are all required to work fine if no previous hints are supplied (or if existing hints are lost). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-20 17:21:28 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: when reloading a discard bitset allow for a different discard block size The discard block size can change if the origin changes size or if an old DM cache is upgraded from using a discard block size that was equal to cache block size. To fix this an extent of discarded blocks is established for the purpose of translating the old discard block size to the new in-core discard block size and set bits. The old (potentially huge) discard bitset is left ondisk until it is re-written using the new in-core information on the next successful DM cache shutdown. Fixes: 7ae34e777896 ("dm cache: improve discard support") Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-24 14:06:22 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: when reloading a discard bitset allow for a different discard block size The discard block size can change if the origin changes size or if an old DM cache is upgraded from using a discard block size that was equal to cache block size. To fix this an extent of discarded blocks is established for the purpose of translating the old discard block size to the new in-core discard block size and set bits. The old (potentially huge) discard bitset is left ondisk until it is re-written using the new in-core information on the next successful DM cache shutdown. Fixes: 7ae34e777896 ("dm cache: improve discard support") Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-24 14:06:22 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add block sizes and total cache blocks to status output Improve cache_status to emit: <metadata block size> <#used metadata blocks>/<#total metadata blocks> <cache block size> <#used cache blocks>/<#total cache blocks> ... Adding the block sizes allows for easier calculation of the overall size of both the metadata and cache devices. Adding <#total cache blocks> provides useful context for how much of the cache is used. Unfortunately these additions to the status will require updates to users' scripts that monitor the cache status. But these changes help provide more comprehensive information about the cache device and will simplify tools that are being developed to manage dm-cache devices -- because they won't need to issue 3 operations to cobble together the information that we can easily provide via a single status ioctl. While updating the status documentation in cache.txt spaces were tabify'd. Requested-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2014-01-09 16:04:12 -05:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add block sizes and total cache blocks to status output Improve cache_status to emit: <metadata block size> <#used metadata blocks>/<#total metadata blocks> <cache block size> <#used cache blocks>/<#total cache blocks> ... Adding the block sizes allows for easier calculation of the overall size of both the metadata and cache devices. Adding <#total cache blocks> provides useful context for how much of the cache is used. Unfortunately these additions to the status will require updates to users' scripts that monitor the cache status. But these changes help provide more comprehensive information about the cache device and will simplify tools that are being developed to manage dm-cache devices -- because they won't need to issue 3 operations to cobble together the information that we can easily provide via a single status ioctl. While updating the status documentation in cache.txt spaces were tabify'd. Requested-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2014-01-09 16:04:12 -05:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: display 'needs_check' in status if it is set There is currently no way to see that the needs_check flag has been set in the metadata. Display 'needs_check' in the cache status if it is set in the cache metadata. Also, update cache documentation. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-07-15 11:42:59 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: make sure every metadata function checks fail_io commit d14fcf3dd79c0b8a8d0ba469c44a6b04f3a1403b upstream. Otherwise operations may be attempted that will only ever go on to crash (since the metadata device is either missing or unreliable if 'fail_io' is set). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-10 16:20:58 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix race affecting dirty block count nr_dirty is updated without locking, causing it to drift so that it is non-zero (either a small positive integer, or a very large one when an underflow occurs) even when there are no actual dirty blocks. This was due to a race between the workqueue and map function accessing nr_dirty in parallel without proper protection. People were seeing under runs due to a race on increment/decrement of nr_dirty, see: https://lkml.org/lkml/2014/6/3/648 Fix this by using an atomic_t for nr_dirty. Reported-by: roma1390@gmail.com Signed-off-by: Anssi Hannula <anssi.hannula@iki.fi> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2014-08-01 11:55:47 -04:00
dm cache metadata: use dm-space-map-metadata.h defined size limits Commit 7d48935e cleaned up the persistent-data's space-map-metadata limits by elevating them to dm-space-map-metadata.h. Update dm-cache-metadata to use these same limits. The calculation for DM_CACHE_METADATA_MAX_SECTORS didn't account for the sizeof the disk_bitmap_header. So the supported maximum metadata size is a bit smaller (reduced from 33423360 to 33292800 sectors). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2014-07-14 15:37:18 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add block sizes and total cache blocks to status output Improve cache_status to emit: <metadata block size> <#used metadata blocks>/<#total metadata blocks> <cache block size> <#used cache blocks>/<#total cache blocks> ... Adding the block sizes allows for easier calculation of the overall size of both the metadata and cache devices. Adding <#total cache blocks> provides useful context for how much of the cache is used. Unfortunately these additions to the status will require updates to users' scripts that monitor the cache status. But these changes help provide more comprehensive information about the cache device and will simplify tools that are being developed to manage dm-cache devices -- because they won't need to issue 3 operations to cobble together the information that we can easily provide via a single status ioctl. While updating the status documentation in cache.txt spaces were tabify'd. Requested-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2014-01-09 16:04:12 -05:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix race affecting dirty block count nr_dirty is updated without locking, causing it to drift so that it is non-zero (either a small positive integer, or a very large one when an underflow occurs) even when there are no actual dirty blocks. This was due to a race between the workqueue and map function accessing nr_dirty in parallel without proper protection. People were seeing under runs due to a race on increment/decrement of nr_dirty, see: https://lkml.org/lkml/2014/6/3/648 Fix this by using an atomic_t for nr_dirty. Reported-by: roma1390@gmail.com Signed-off-by: Anssi Hannula <anssi.hannula@iki.fi> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2014-08-01 11:55:47 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: add passthrough mode "Passthrough" is a dm-cache operating mode (like writethrough or writeback) which is intended to be used when the cache contents are not known to be coherent with the origin device. It behaves as follows: * All reads are served from the origin device (all reads miss the cache) * All writes are forwarded to the origin device; additionally, write hits cause cache block invalidates This mode decouples cache coherency checks from cache device creation, largely to avoid having to perform coherency checks while booting. Boot scripts can create cache devices in passthrough mode and put them into service (mount cached filesystems, for example) without having to worry about coherency. Coherency that exists is maintained, although the cache will gradually cool as writes take place. Later, applications can perform coherency checks, the nature of which will depend on the type of the underlying storage. If coherency can be verified, the cache device can be transitioned to writethrough or writeback mode while still warm; otherwise, the cache contents can be discarded prior to transitioning to the desired operating mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-10-24 14:10:29 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add policy name to status output The cache's policy may have been established using the "default" alias, which is currently the "mq" policy but the default policy may change in the future. It is useful to know exactly which policy is being used. Add a 'real' member to the dm_cache_policy_type structure and have the "default" dm_cache_policy_type point to the real "mq" dm_cache_policy_type. Update dm_cache_policy_get_name() to check if real is set, if so report the name of the real policy (not the alias). Requested-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-01-15 21:06:55 -05:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm cache: make sure every metadata function checks fail_io commit d14fcf3dd79c0b8a8d0ba469c44a6b04f3a1403b upstream. Otherwise operations may be attempted that will only ever go on to crash (since the metadata device is either missing or unreliable if 'fail_io' is set). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-10 16:20:58 +00:00
dm cache: display 'needs_check' in status if it is set There is currently no way to see that the needs_check flag has been set in the metadata. Display 'needs_check' in the cache status if it is set in the cache metadata. Also, update cache documentation. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-07-15 11:42:59 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm cache: prefix all DMERR and DMINFO messages with cache device name Having the DM device name associated with the ERR or INFO message is very helpful. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 17:25:56 -04:00
dm cache: add fail io mode and needs_check flag If a cache metadata operation fails (e.g. transaction commit) the cache's metadata device will abort the current transaction, set a new needs_check flag, and the cache will transition to "read-only" mode. If aborting the transaction or setting the needs_check flag fails the cache will transition to "fail-io" mode. Once needs_check is set the cache device will not be allowed to activate. Activation requires write access to metadata. Future work is needed to add proper support for running the cache in read-only mode. Once in fail-io mode the cache will report a status of "Fail". Also, add commit() wrapper that will disallow commits if in read_only or fail mode. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-22 16:42:35 -04:00
dm cache: resolve small nits and improve Documentation Document passthrough mode, cache shrinking, and cache invalidation. Also, use strcasecmp() and hlist_unhashed(). Reported-by: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-12 12:17:43 -05:00
dm cache: add cache block invalidation support Cache block invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the 'invalidate_cblocks' message, which takes an arbitrary number of cblock ranges: invalidate_cblocks [<cblock>|<cblock begin>-<cblock end>]* E.g. dmsetup message my_cache 0 invalidate_cblocks 2345 3456-4567 5678-6789 Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-08 16:39:50 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: set config value Share configuration option processing code between the dm cache ctr and message functions. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-05-10 14:37:21 +01:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: improve discard support Safely allow the discard blocksize to be larger than the cache blocksize by using the bio prison's range locking support. This also improves discard performance considerly because larger discards are issued to the dm-cache device. The discard blocksize was always intended to be greater than the cache blocksize. But until now it wasn't implemented safely. Also, by safely restoring the ability to have discard blocksize larger than cache blocksize we're able to significantly reduce the memory used for the cache's discard bitset. Before, with a small discard blocksize, the discard bitset could get quite large because its size is a function of the discard blocksize and the origin device's size. For example, previously, using a 32KB cache blocksize with a 40TB origin resulted in 1280MB of incore memory use for the discard bitset! Now, the discard blocksize is scaled up accordingly to ensure the discard bitset is capped at 2**14 bits, or 16KB. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-06 10:18:04 +00:00
dm cache: revert "remove remainder of distinct discard block size" This reverts commit 64ab346a360a4b15c28fb8531918d4a01f4eabd9 because we actually do want to allow the discard blocksize to be larger than the cache blocksize. Further dm-cache discard changes will make this possible. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-11-07 14:47:07 +00:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix stacking of geometry limits Do not blindly override the queue limits (specifically io_min and io_opt). Allow traditional stacking of these limits if io_opt is a factor of the cache's data block size. Without this patch mkfs.xfs does not recognize the cache device's provided limits as a useful geometry (e.g. raid) so these hints are ignored. This was due to setting io_min to a useless value. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2013-08-20 15:02:41 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: fix stacking of geometry limits Do not blindly override the queue limits (specifically io_min and io_opt). Allow traditional stacking of these limits if io_opt is a factor of the cache's data block size. Without this patch mkfs.xfs does not recognize the cache device's provided limits as a useful geometry (e.g. raid) so these hints are ignored. This was due to setting io_min to a useless value. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2013-08-20 15:02:41 -04:00
dm cache: set minimum_io_size to cache's data block size Before, if the block layer's limit stacking didn't establish an optimal_io_size that was compatible with the cache's data block size we'd set optimal_io_size to the data block size and minimum_io_size to 0 (which the block layer adjusts to be physical_block_size). Update cache_io_hints() to set both minimum_io_size and optimal_io_size to the cache's data block size. This fixes an issue where mkfs.xfs would create more XFS Allocation Groups on cache volumes than on a normal linear LV of comparable size. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-07-19 13:25:46 -04:00
dm cache: fix stacking of geometry limits Do not blindly override the queue limits (specifically io_min and io_opt). Allow traditional stacking of these limits if io_opt is a factor of the cache's data block size. Without this patch mkfs.xfs does not recognize the cache device's provided limits as a useful geometry (e.g. raid) so these hints are ignored. This was due to setting io_min to a useless value. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2013-08-20 15:02:41 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00
dm cache: display 'needs_check' in status if it is set There is currently no way to see that the needs_check flag has been set in the metadata. Display 'needs_check' in the cache status if it is set in the cache metadata. Also, update cache documentation. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-07-15 11:42:59 -04:00
dm: add cache target Add a target that allows a fast device such as an SSD to be used as a cache for a slower device such as a disk. A plug-in architecture was chosen so that the decisions about which data to migrate and when are delegated to interchangeable tunable policy modules. The first general purpose module we have developed, called "mq" (multiqueue), follows in the next patch. Other modules are under development. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:51 +00:00