linux/drivers/md
Mikulas Patocka e33972a9b5 dm snapshot: fix hung bios when copy error occurs
commit 385277bfb5 upstream.

When there is an error copying a chunk dm-snapshot can incorrectly hold
associated bios indefinitely, resulting in hung IO.

The function copy_callback sets pe->error if there was error copying the
chunk, and then calls complete_exception.  complete_exception calls
pending_complete on error, otherwise it calls commit_exception with
commit_callback (and commit_callback calls complete_exception).

The persistent exception store (dm-snap-persistent.c) assumes that calls
to prepare_exception and commit_exception are paired.
persistent_prepare_exception increases ps->pending_count and
persistent_commit_exception decreases it.

If there is a copy error, persistent_prepare_exception is called but
persistent_commit_exception is not.  This results in the variable
ps->pending_count never returning to zero and that causes some pending
exceptions (and their associated bios) to be held forever.

Fix this by unconditionally calling commit_exception regardless of
whether the copy was successful.  A new "valid" parameter is added to
commit_exception -- when the copy fails this parameter is set to zero so
that the chunk that failed to copy (and all following chunks) is not
recorded in the snapshot store.  Also, remove commit_callback now that
it is merely a wrapper around pending_complete.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
History 2016-02-02 19:09:21 +00:00
..
bcache bcache: Change refill_dirty() to always scan entire disk if necessary 2016-02-02 19:09:12 +00:00
persistent-data dm space map metadata: remove unused variable in brb_pop() 2016-02-02 17:38:40 +00:00
bitmap.c md/bitmap: return an error when bitmap superblock is corrupt. 2015-08-27 12:08:08 +01:00
bitmap.h kernfs: s/sysfs_dirent/kernfs_node/ and rename its friends accordingly 2013-12-11 15:28:36 -08:00
dm-bio-prison.c dm bio prison: implement per bucket locking in the dm_bio_prison hash table 2014-06-11 16:48:54 -04:00
dm-bio-prison.h dm thin: return ENOSPC instead of EIO when error_if_no_space enabled 2014-06-03 13:44:08 -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 memleak when using a dm_buffer's inline bio 2015-01-12 15:44:07 +00:00
dm-bufio.h dm snapshot: use dm-bufio prefetch 2014-01-14 23:23:03 -05:00
dm-builtin.c dm sysfs: fix a module unload race 2014-01-14 23:23:04 -05:00
dm-cache-block-types.h dm cache: remove remainder of distinct discard block size 2014-03-27 16:56:23 -04:00
dm-cache-metadata.c dm cache: fix missing ERR_PTR returns and handling 2015-02-04 10:58:25 +00:00
dm-cache-metadata.h dm cache: fix a lock-inversion 2014-04-04 14:53:05 -04:00
dm-cache-policy-cleaner.c dm cache: fix NULL pointer when switching from cleaner policy 2015-10-30 13:59:29 +00:00
dm-cache-policy-internal.h dm cache: add remove_cblock method to policy interface 2013-11-11 11:37:50 -05:00
dm-cache-policy-mq.c dm cache mq: fix memory allocation failure for large cache devices 2014-02-28 12:18:29 -05:00
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: add policy name to status output 2014-01-16 13:44:11 -05:00
dm-cache-target.c dm cache: fix problematic dual use of a single migration count variable 2015-02-04 10:57:46 +00:00
dm-crypt.c dm crypt: use memzero_explicit for on-stack buffer 2015-01-12 15:44:12 +00:00
dm-delay.c Merge branch 'for-3.14/core' of git://git.kernel.dk/linux-block 2014-01-30 11:19:05 -08:00
dm-era-target.c dm era: check for a non-NULL metadata object before closing it 2014-06-03 13:44:08 -04:00
dm-exception-store.c dm: replace simple_strtoul 2012-07-27 15:07:59 +01:00
dm-exception-store.h dm snapshot: fix hung bios when copy error occurs 2016-02-02 19:09:21 +00:00
dm-flakey.c block: Abstract out bvec iterator 2013-11-23 22:33:47 -08:00
dm-io.c dm io: deal with wandering queue limits when handling REQ_DISCARD and REQ_WRITE_SAME 2015-03-30 11:10:44 +01:00
dm-ioctl.c dm: allow remove to be deferred 2013-11-09 18:20:22 -05:00
dm-kcopyd.c dm: stop using WQ_NON_REENTRANT 2013-08-23 09:02:13 -04:00
dm-linear.c block: Abstract out bvec iterator 2013-11-23 22:33:47 -08:00
dm-log-userspace-base.c dm log userspace: allow mark requests to piggyback on flush requests 2014-01-21 23:46:27 -05:00
dm-log-userspace-transfer.c dm log userspace: fix memory leak in dm_ulog_tfr_init failure path 2014-11-17 14:11:44 +00:00
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.c dm: use memweight() 2012-07-30 17:25:16 -07:00
dm-mpath.c dm: fix ioctl retry termination with signal 2015-12-18 16:06:27 +00:00
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 mpath: add start_io and nr_bytes to path selectors 2009-06-22 10:12:27 +01:00
dm-queue-length.c dm: reject trailing characters in sccanf input 2012-03-28 18:41:26 +01:00
dm-raid.c dm raid: fix round up of default region size 2015-10-30 13:59:28 +00:00
dm-raid1.c dm mirror: do not degrade the mirror on discard error 2015-03-02 15:04:24 +00:00
dm-region-hash.c block: Abstract out bvec iterator 2013-11-23 22:33:47 -08:00
dm-round-robin.c dm: reject trailing characters in sccanf input 2012-03-28 18:41:26 +01:00
dm-service-time.c dm: reject trailing characters in sccanf input 2012-03-28 18:41:26 +01:00
dm-snap-persistent.c dm snapshot: fix hung bios when copy error occurs 2016-02-02 19:09:21 +00:00
dm-snap-transient.c dm snapshot: fix hung bios when copy error occurs 2016-02-02 19:09:21 +00:00
dm-snap.c dm snapshot: fix hung bios when copy error occurs 2016-02-02 19:09:21 +00:00
dm-stats.c dm stats: fix divide by zero if 'number_of_areas' arg is zero 2015-07-15 10:00:41 +01:00
dm-stats.h dm: add statistics support 2013-09-05 20:46:06 -04:00
dm-stripe.c block: Abstract out bvec iterator 2013-11-23 22:33:47 -08:00
dm-switch.c block: Abstract out bvec iterator 2013-11-23 22:33:47 -08:00
dm-sysfs.c dm sysfs: fix a module unload race 2014-01-14 23:23:04 -05:00
dm-table.c dm table: propagate QUEUE_FLAG_NO_SG_MERGE 2014-09-17 09:22:21 -07:00
dm-target.c dm: allow error target to replace bio-based and request-based targets 2013-09-05 20:46:05 -04:00
dm-thin-metadata.c dm thin metadata: fix bug when taking a metadata snapshot 2016-01-18 22:27:24 +00:00
dm-thin-metadata.h dm thin: ensure user takes action to validate data and metadata consistency 2014-03-05 15:25:35 -05:00
dm-thin.c dm thin: fix race condition when destroying thin pool workqueue 2016-02-02 17:38:40 +00:00
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.c dm verity: fix biovecs hash calculation regression 2014-04-15 12:19:24 -04:00
dm-zero.c dm crypt, dm zero: update author name following legal name change 2014-07-10 16:44:14 -04:00
dm.c dm: fix ioctl retry termination with signal 2015-12-18 16:06:27 +00:00
dm.h dm table: add dm_table_run_md_queue_async 2014-03-27 16:56:24 -04:00
faulty.c block: Abstract out bvec iterator 2013-11-23 22:33:47 -08:00
Kconfig scsi_dh: fix randconfig build error 2015-09-30 13:20:52 +01:00
linear.c block: Introduce new bio_split() 2013-11-23 22:33:57 -08:00
linear.h md/linear: typedef removal: linear_conf_t -> struct linear_conf 2011-10-11 16:48:54 +11:00
Makefile dm: add era target 2014-03-27 16:56:23 -04:00
md.c Revert "md: allow a partially recovered device to be hot-added to an array." 2015-11-16 11:27:17 +00:00
md.h md/bitmap: don't abuse i_writecount for bitmap files. 2014-04-09 12:26:59 +10:00
multipath.c block: Abstract out bvec iterator 2013-11-23 22:33:47 -08:00
multipath.h md/multipath: typedef removal: multipath_conf_t -> struct mpconf 2011-10-11 16:48:57 +11:00
raid0.c md/raid0: apply base queue limits *before* disk_stack_limits 2015-12-13 17:49:47 +00:00
raid0.h md: add proper merge_bvec handling to RAID0 and Linear. 2012-03-19 12:46:39 +11:00
raid1.c md/raid1: submit_bio_wait() returns 0 on success 2015-11-16 11:27:10 +00:00
raid1.h raid1: Rewrite the implementation of iobarrier. 2013-11-19 15:19:18 +11:00
raid5.c md/raid5: fix locking in handle_stripe_clean_event() 2015-11-16 11:27:16 +00:00
raid5.h raid5: add an option to avoid copy data from bio to stripe cache 2014-05-29 16:59:47 +10:00
raid10.c md/raid10: submit_bio_wait() returns 0 on success 2015-11-16 11:27:10 +00:00
raid10.h MD RAID10: Improve redundancy for 'far' and 'offset' algorithms (part 1) 2013-02-26 11:55:30 +11:00