linux/drivers/md
Rui Hua 9db9b5f2b1 bcache: recover data from backing when data is clean
commit e393aa2446 upstream.

When we send a read request and hit the clean data in cache device, there
is a situation called cache read race in bcache(see the commit in the tail
of cache_look_up(), the following explaination just copy from there):
The bucket we're reading from might be reused while our bio is in flight,
and we could then end up reading the wrong data. We guard against this
by checking (in bch_cache_read_endio()) if the pointer is stale again;
if so, we treat it as an error (s->iop.error = -EINTR) and reread from
the backing device (but we don't pass that error up anywhere)

It should be noted that cache read race happened under normal
circumstances, not the circumstance when SSD failed, it was counted
and shown in  /sys/fs/bcache/XXX/internal/cache_read_races.

Without this patch, when we use writeback mode, we will never reread from
the backing device when cache read race happened, until the whole cache
device is clean, because the condition
(s->recoverable && (dc && !atomic_read(&dc->has_dirty))) is false in
cached_dev_read_error(). In this situation, the s->iop.error(= -EINTR)
will be passed up, at last, user will receive -EINTR when it's bio end,
this is not suitable, and wield to up-application.

In this patch, we use s->read_dirty_data to judge whether the read
request hit dirty data in cache device, it is safe to reread data from
the backing device when the read request hit clean data. This can not
only handle cache read race, but also recover data when failed read
request from cache device.

[edited by mlyle to fix up whitespace, commit log title, comment
spelling]

Fixes: d59b237959 ("bcache: only permit to recovery read error when cache device is clean")
Signed-off-by: Hua Rui <huarui.dev@gmail.com>
Reviewed-by: Michael Lyle <mlyle@lyle.org>
Reviewed-by: Coly Li <colyli@suse.de>
Signed-off-by: Michael Lyle <mlyle@lyle.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2017-12-09 22:01:46 +01:00
..
bcache bcache: recover data from backing when data is clean 2017-12-09 22:01:46 +01:00
persistent-data dm space map disk: fix some book keeping in the disk space map 2017-05-25 15:44:33 +02:00
bitmap.c md/bitmap: disable bitmap_resize for file-backed bitmaps. 2017-09-27 14:39:21 +02:00
bitmap.h md-cluster: sync bitmap when node received RESYNCING msg 2016-05-04 12:39:35 -07:00
dm-bio-prison.c block: add a bi_error field to struct bio 2015-07-29 08:55:15 -06:00
dm-bio-prison.h dm bio prison: add dm_cell_promote_or_release() 2015-05-29 14:19:06 -04:00
dm-bio-record.h dm: Refactor for new bio cloning/splitting 2013-11-23 22:33:55 -08:00
dm-bufio.c dm bufio: fix integer overflow when limiting maximum cache size 2017-11-30 08:39:02 +00:00
dm-bufio.h dm snapshot: use dm-bufio prefetch 2014-01-14 23:23:03 -05:00
dm-builtin.c dm: move request-based code out to dm-rq.[hc] 2016-06-10 15:15:44 -04:00
dm-cache-block-types.h dm cache: revert "remove remainder of distinct discard block size" 2014-11-10 15:25:30 -05:00
dm-cache-metadata.c dm cache metadata: fail operations if fail_io mode has been established 2017-05-25 15:44:33 +02:00
dm-cache-metadata.h dm cache: make sure every metadata function checks fail_io 2016-03-10 17:12:12 -05:00
dm-cache-policy-cleaner.c dm cache: speed up writing of the hint array 2016-09-22 11:15:02 -04:00
dm-cache-policy-internal.h dm cache: speed up writing of the hint array 2016-09-22 11:15:02 -04:00
dm-cache-policy-smq.c dm cache policy smq: distribute entries to random levels when switching to smq 2016-09-22 11:15:03 -04:00
dm-cache-policy.c dm cache: add policy name to status output 2014-01-16 13:44:11 -05:00
dm-cache-policy.h dm cache: speed up writing of the hint array 2016-09-22 11:15:02 -04:00
dm-cache-target.c dm cache: fix corruption seen when using cache > 2TB 2017-03-12 06:41:44 +01:00
dm-core.h dm: allocate struct mapped_device with kvzalloc 2017-11-30 08:39:02 +00:00
dm-crypt.c dm crypt: mark key as invalid until properly loaded 2017-01-06 10:40:15 +01:00
dm-delay.c dm: rename target's per_bio_data_size to per_io_data_size 2016-02-22 22:34:37 -05:00
dm-era-target.c dm era: save spacemap metadata root after the pre-commit 2017-05-20 14:28:37 +02:00
dm-exception-store.c - Revert a dm-multipath change that caused a regression for unprivledged 2015-11-04 21:19:53 -08:00
dm-exception-store.h dm snapshot: fix hung bios when copy error occurs 2016-01-08 20:03:05 -05:00
dm-flakey.c dm flakey: return -EINVAL on interval bounds error in flakey_ctr() 2017-01-06 10:40:15 +01:00
dm-io.c block: rename bio bi_rw to bi_opf 2016-08-07 14:41:02 -06:00
dm-ioctl.c dm ioctl: prevent stack leak in dm ioctl call 2017-05-08 07:47:55 +02:00
dm-kcopyd.c dm: move request-based code out to dm-rq.[hc] 2016-06-10 15:15:44 -04:00
dm-linear.c libnvdimm for 4.8 2016-07-28 17:38:16 -07:00
dm-log-userspace-base.c dm: drop NULL test before kmem_cache_destroy() and mempool_destroy() 2015-10-31 19:06:00 -04:00
dm-log-userspace-transfer.c dm log userspace transfer: match wait_for_completion_timeout return type 2015-04-15 12:10:20 -04:00
dm-log-userspace-transfer.h dm log: userspace add luid to distinguish between concurrent log instances 2009-09-04 20:40:34 +01:00
dm-log-writes.c Merge branch 'for-4.9/block' of git://git.kernel.dk/linux-block 2016-10-07 14:42:05 -07:00
dm-log.c dm log: fix unitialized bio operation flags 2016-08-24 21:55:05 -04:00
dm-mpath.c dm mpath: cleanup -Wbool-operation warning in choose_pgpath() 2017-07-27 15:07:55 -07:00
dm-mpath.h dm mpath: remove is_active from struct dm_path 2008-10-10 13:36:58 +01:00
dm-path-selector.c md: Add module.h to all files using it implicitly 2011-10-31 19:31:18 -04:00
dm-path-selector.h dm path selector: remove 'repeat_count' return from .select_path hook 2016-02-22 22:34:42 -05:00
dm-queue-length.c dm path selector: remove 'repeat_count' return from .select_path hook 2016-02-22 22:34:42 -05:00
dm-raid.c dm raid: fix NULL pointer dereference for raid1 without bitmap 2017-04-12 12:41:13 +02:00
dm-raid1.c dm mirror: use all available legs on multiple failures 2016-10-14 11:55:17 -04:00
dm-region-hash.c block: rename bio bi_rw to bi_opf 2016-08-07 14:41:02 -06:00
dm-round-robin.c dm round robin: revert "use percpu 'repeat_count' and 'current_path'" 2017-03-12 06:41:44 +01:00
dm-rq.c dm rq: check blk_mq_register_dev() return value in dm_mq_init_request_queue() 2017-05-20 14:28:37 +02:00
dm-rq.h dm rq: introduce dm_mq_kick_requeue_list() 2016-09-15 11:16:05 -04:00
dm-service-time.c dm path selector: remove 'repeat_count' return from .select_path hook 2016-02-22 22:34:42 -05:00
dm-snap-persistent.c dm: use bio op accessors 2016-06-07 13:41:38 -06:00
dm-snap-transient.c dm snapshot: fix hung bios when copy error occurs 2016-01-08 20:03:05 -05:00
dm-snap.c block: rename bio bi_rw to bi_opf 2016-08-07 14:41:02 -06:00
dm-stats.c dm stats: fix a leaked s->histogram_boundaries array 2017-03-12 06:41:44 +01:00
dm-stats.h dm stats: support precise timestamps 2015-06-17 12:40:40 -04:00
dm-stripe.c block: rename bio bi_rw to bi_opf 2016-08-07 14:41:02 -06:00
dm-switch.c dm switch: simplify conditional in alloc_region_table() 2015-10-31 19:06:06 -04:00
dm-sysfs.c dm: move request-based code out to dm-rq.[hc] 2016-06-10 15:15:44 -04:00
dm-table.c dm table: an 'all_blk_mq' table must be loaded for a blk-mq DM device 2017-01-06 10:40:15 +01:00
dm-target.c libnvdimm for 4.8 2016-07-28 17:38:16 -07:00
dm-thin-metadata.c dm thin metadata: call precommit before saving the roots 2017-05-25 15:44:33 +02:00
dm-thin-metadata.h dm thin: fix a race condition between discarding and provisioning a block 2016-07-20 12:43:35 -04:00
dm-thin.c dm thin: do not queue freed thin mapping for next stage processing 2017-07-05 14:40:18 +02:00
dm-uevent.c md: Add in export.h for files using EXPORT_SYMBOL 2011-10-31 19:31:19 -04:00
dm-uevent.h dm: uevent generate events 2007-10-20 02:01:26 +01:00
dm-verity-fec.c dm verity fec: fix bufio leaks 2017-04-12 12:41:12 +02:00
dm-verity-fec.h dm verity fec: limit error correction recursion 2017-04-12 12:41:12 +02:00
dm-verity-target.c dm: rename target's per_bio_data_size to per_io_data_size 2016-02-22 22:34:37 -05:00
dm-verity.h dm verity: add ignore_zero_blocks feature 2015-12-10 10:39:03 -05:00
dm-zero.c block: rename bio bi_rw to bi_opf 2016-08-07 14:41:02 -06:00
dm.c dm: fix race between dm_get_from_kobject() and __dm_destroy() 2017-11-30 08:39:02 +00:00
dm.h dm: add infrastructure for DAX support 2016-07-20 23:49:49 -04:00
faulty.c MD: rename some functions 2016-01-20 13:52:20 -08:00
Kconfig dm raid: select the Kconfig option CONFIG_MD_RAID0 2017-05-25 15:44:33 +02:00
linear.c md/linear: shutup lockdep warnning 2017-10-21 17:21:35 +02:00
linear.h md linear: fix a race between linear_add() and linear_congested() 2017-03-12 06:41:52 +01:00
Makefile dm: move request-based code out to dm-rq.[hc] 2016-06-10 15:15:44 -04:00
md-cluster.c md-cluster: make resync lock also could be interruptted 2016-09-21 09:09:44 -07:00
md-cluster.h md-cluster: gather resync infos and enable recv_thread after bitmap is ready 2016-05-09 09:24:03 -07:00
md.c md: fix super_offset endianness in super_1_rdev_size_change 2017-07-15 12:16:15 +02:00
md.h md: changes for MD_STILL_CLOSED flag 2016-09-21 09:09:44 -07:00
multipath.c block: rename bio bi_rw to bi_opf 2016-08-07 14:41:02 -06:00
multipath.h md/multipath: typedef removal: multipath_conf_t -> struct mpconf 2011-10-11 16:48:57 +11:00
raid0.c block: rename bio bi_rw to bi_opf 2016-08-07 14:41:02 -06:00
raid0.h block: kill merge_bvec_fn() completely 2015-08-13 12:31:57 -06:00
raid1.c md: don't use flush_signals in userspace processes 2017-07-27 15:08:01 -07:00
raid1.h md-cluster: Use a small window for resync 2015-10-12 01:32:05 -05:00
raid5-cache.c raid5-cache: correct condition for empty metadata write 2016-10-28 22:04:03 -07:00
raid5.c md/raid5: preserve STRIPE_ON_UNPLUG_LIST in break_stripe_batch_list 2017-10-05 09:43:59 +02:00
raid5.h md/raid5: Convert to hotplug state machine 2016-09-06 18:30:23 +02:00
raid10.c md/raid10: submit bio directly to replacement disk 2017-10-08 10:26:11 +02:00
raid10.h raid10: improve random reads performance 2016-07-19 15:20:28 -07:00