linux/drivers/md
Joe Thornber 19fa1a6756 dm thin: fix discard support to a previously shared block
If a snapshot is created and later deleted the origin dm_thin_device's
snapshotted_time will have been updated to reflect the snapshot's
creation time.  The 'shared' flag in the dm_thin_lookup_result struct
returned from dm_thin_find_block() is an approximation based on
snapshotted_time -- this is done to avoid 0(n), or worse, time
complexity.  In this case, the shared flag would be true.

But because the 'shared' flag reflects an approximation a block can be
incorrectly assumed to be shared (e.g. false positive for 'shared'
because the snapshot no longer exists).  This could result in discards
issued to a thin device not being passed down to the pool's underlying
data device.

To fix this we double check that a thin block is really still in-use
after a mapping is removed using dm_pool_block_is_used().  If the
reference count for a block is now zero the discard is allowed to be
passed down.

Also add a 'definitely_not_shared' member to the dm_thin_new_mapping
structure -- reflects that the 'shared' flag in the response from
dm_thin_find_block() can only be held as definitive if false is
returned.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1043527

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2014-01-07 10:11:43 -05:00
..
bcache bcache: defensively handle format strings 2013-11-10 21:56:43 -08:00
persistent-data dm array: fix a reference counting bug in shadow_ablock 2013-12-13 14:22:10 -05:00
bitmap.c sysfs: clean up sysfs_get_dirent() 2013-09-26 15:33:18 -07:00
bitmap.h
dm-bio-prison.c
dm-bio-prison.h
dm-bio-record.h
dm-bufio.c dm bufio: initialize read-only module parameters 2013-12-10 19:13:20 -05:00
dm-bufio.h
dm-cache-block-types.h
dm-cache-metadata.c dm cache metadata: check the metadata version when reading the superblock 2013-11-11 11:37:49 -05:00
dm-cache-metadata.h dm cache: add passthrough mode 2013-11-11 11:37:49 -05:00
dm-cache-policy-cleaner.c
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 policy mq: fix promotions to occur as expected 2013-12-10 16:35:14 -05:00
dm-cache-policy.c dm cache: return -EINVAL if the user specifies unknown cache policy 2013-11-09 18:20:18 -05:00
dm-cache-policy.h dm cache: add remove_cblock method to policy interface 2013-11-11 11:37:50 -05:00
dm-cache-target.c dm cache: actually resize cache 2013-12-10 16:35:15 -05:00
dm-crypt.c tree-wide: use reinit_completion instead of INIT_COMPLETION 2013-11-15 09:32:21 +09:00
dm-delay.c dm delay: fix a possible deadlock due to shared workqueue 2013-11-18 11:23:21 -05:00
dm-exception-store.c
dm-exception-store.h
dm-flakey.c dm flakey: correct ctr alloc failure mesg 2013-07-10 23:41:17 +01:00
dm-io.c dm: add reserved_bio_based_ios module parameter 2013-09-23 10:42:24 -04:00
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
dm-log-userspace-base.c
dm-log-userspace-transfer.c
dm-log-userspace-transfer.h
dm-log.c
dm-mpath.c dm mpath: requeue I/O during pg_init 2013-11-05 11:20:34 -05:00
dm-mpath.h
dm-path-selector.c
dm-path-selector.h
dm-queue-length.c
dm-raid1.c dm: stop using WQ_NON_REENTRANT 2013-08-23 09:02:13 -04:00
dm-raid.c MD: Remember the last sync operation that was performed 2013-06-26 12:38:24 +10:00
dm-region-hash.c
dm-round-robin.c
dm-service-time.c
dm-snap-persistent.c dm snapshot: fix data corruption 2013-10-16 03:17:47 +01:00
dm-snap-transient.c
dm-snap.c dm snapshot: avoid snapshot space leak on crash 2013-12-10 16:34:25 -05:00
dm-stats.c dm stats: initialize read-only module parameter 2013-12-10 19:13:21 -05:00
dm-stats.h dm: add statistics support 2013-09-05 20:46:06 -04:00
dm-stripe.c dm stripe: silence a couple sparse warnings 2013-09-06 11:36:01 -04:00
dm-switch.c dm: add switch target 2013-07-10 23:41:19 +01:00
dm-sysfs.c
dm-table.c dm table: fail dm_table_create on dm_round_up overflow 2013-12-10 16:34:27 -05:00
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: fix discard support to a previously shared block 2014-01-07 10:11:43 -05:00
dm-thin-metadata.h dm thin: fix discard support to a previously shared block 2014-01-07 10:11:43 -05:00
dm-thin.c dm thin: fix discard support to a previously shared block 2014-01-07 10:11:43 -05:00
dm-uevent.c
dm-uevent.h
dm-verity.c dm verity: use __ffs and __fls 2013-07-10 23:41:17 +01:00
dm-zero.c
dm.c dm: allow remove to be deferred 2013-11-09 18:20:22 -05:00
dm.h dm: allow remove to be deferred 2013-11-09 18:20:22 -05:00
faulty.c
Kconfig dm: fix Kconfig menu indentation 2013-11-09 18:20:22 -05:00
linear.c
linear.h
Makefile dm: add statistics support 2013-09-05 20:46:06 -04:00
md.c Merge branch 'for-linus' of git://git.kernel.dk/linux-block 2013-12-05 15:33:27 -08:00
md.h Merge branch 'for-3.13/core' of git://git.kernel.dk/linux-block 2013-11-14 12:08:14 +09:00
multipath.c
multipath.h
raid0.c md: fix buglet in RAID5 -> RAID0 conversion. 2013-06-26 12:38:19 +10:00
raid0.h
raid1.c md update for 3.13. 2013-11-20 13:05:25 -08:00
raid1.h raid1: Rewrite the implementation of iobarrier. 2013-11-19 15:19:18 +11:00
raid5.c md/raid5: fix newly-broken locking in get_active_stripe. 2013-11-28 11:00:15 +11:00
raid5.h md update for 3.13. 2013-11-20 13:05:25 -08:00
raid10.c md update for 3.13. 2013-11-20 13:05:25 -08:00
raid10.h