Anssi Hannula
40aa978ecc
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
2014-09-10 11:20:47 -04:00
bcache: Drop unneeded blk_sync_queue() calls
2014-08-04 15:23:04 -07:00
dm transaction manager: fix corruption due to non-atomic transaction commit
2014-03-27 16:56:23 -04:00
md/bitmap: remove confusing code from filemap_get_page.
2014-05-29 16:59:47 +10:00
kernfs: s/sysfs_dirent/kernfs_node/ and rename its friends accordingly
2013-12-11 15:28:36 -08:00
dm bio prison: implement per bucket locking in the dm_bio_prison hash table
2014-06-11 16:48:54 -04:00
dm thin: return ENOSPC instead of EIO when error_if_no_space enabled
2014-06-03 13:44:08 -04:00
dm: Refactor for new bio cloning/splitting
2013-11-23 22:33:55 -08:00
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2014-08-04 16:23:30 -07:00
dm snapshot: use dm-bufio prefetch
2014-01-14 23:23:03 -05:00
dm sysfs: fix a module unload race
2014-01-14 23:23:04 -05:00
dm cache: remove remainder of distinct discard block size
2014-03-27 16:56:23 -04:00
dm cache metadata: use dm-space-map-metadata.h defined size limits
2014-08-01 12:30:33 -04:00
dm cache metadata: use dm-space-map-metadata.h defined size limits
2014-08-01 12:30:33 -04:00
dm cache: add remove_cblock method to policy interface
2013-11-11 11:37:50 -05:00
dm cache mq: fix memory allocation failure for large cache devices
2014-02-28 12:18:29 -05:00
dm cache: add policy name to status output
2014-01-16 13:44:11 -05:00
dm cache: add policy name to status output
2014-01-16 13:44:11 -05:00
dm cache: fix race causing dirty blocks to be marked as clean
2014-09-10 11:20:47 -04:00
dm crypt: fix access beyond the end of allocated space
2014-08-28 14:24:09 -04:00
Merge branch 'for-3.14/core' of git://git.kernel.dk/linux-block
2014-01-30 11:19:05 -08:00
dm era: check for a non-NULL metadata object before closing it
2014-06-03 13:44:08 -04:00
block: Abstract out bvec iterator
2013-11-23 22:33:47 -08:00
dm io: simplify dec_count and sync_io
2014-08-01 12:30:30 -04:00
dm: allow remove to be deferred
2013-11-09 18:20:22 -05:00
dm: stop using WQ_NON_REENTRANT
2013-08-23 09:02:13 -04:00
block: Abstract out bvec iterator
2013-11-23 22:33:47 -08:00
dm log userspace: allow mark requests to piggyback on flush requests
2014-01-21 23:46:27 -05:00
connector: add portid to unicast in addition to broadcasting
2014-02-07 15:40:17 -08:00
dm mpath: eliminate pg_ready() wrapper
2014-08-01 12:30:31 -04:00
dm raid1: fix immutable biovec related BUG when retrying read bio
2014-02-18 10:48:57 -05:00
block: Abstract out bvec iterator
2013-11-23 22:33:47 -08:00
dm snapshot: fix metadata corruption
2014-03-03 17:58:13 -05:00
sched: Remove proliferation of wait_on_bit() action functions
2014-07-16 15:10:39 +02:00
dm stats: initialize read-only module parameter
2013-12-10 19:13:21 -05:00
dm: add statistics support
2013-09-05 20:46:06 -04:00
block: Abstract out bvec iterator
2013-11-23 22:33:47 -08:00
dm switch: efficiently support repetitive patterns
2014-08-01 12:30:37 -04:00
dm sysfs: fix a module unload race
2014-01-14 23:23:04 -05:00
dm table: propagate QUEUE_FLAG_NO_SG_MERGE
2014-08-10 20:54:49 -04:00
dm: allow error target to replace bio-based and request-based targets
2013-09-05 20:46:05 -04:00
dm thin metadata: do not allow the data block size to change
2014-07-15 14:05:26 -04:00
dm thin: ensure user takes action to validate data and metadata consistency
2014-03-05 15:25:35 -05:00
dm thin: set minimum_io_size to pool's data block size
2014-08-01 12:30:35 -04:00
dm verity: fix biovecs hash calculation regression
2014-04-15 12:19:24 -04:00
dm crypt, dm zero: update author name following legal name change
2014-07-10 16:44:14 -04:00
dm: allocate a special workqueue for deferred device removal
2014-07-10 16:44:13 -04:00
dm table: make dm_table_supports_discards static
2014-08-01 12:30:34 -04:00
block: Abstract out bvec iterator
2013-11-23 22:33:47 -08:00
dm: add era target
2014-03-27 16:56:23 -04:00
block: Introduce new bio_split()
2013-11-23 22:33:57 -08:00
dm: add era target
2014-03-27 16:56:23 -04:00
md: don't allow bitmap file to be added to raid0/linear.
2014-08-08 15:43:20 +10:00
md/bitmap: don't abuse i_writecount for bitmap files.
2014-04-09 12:26:59 +10:00
block: Abstract out bvec iterator
2013-11-23 22:33:47 -08:00
md/raid0: check for bitmap compatability when changing raid levels.
2014-08-08 15:33:17 +10:00
md/raid1,raid10: always abort recover on write error.
2014-07-31 10:16:52 +10:00
raid1: Rewrite the implementation of iobarrier.
2013-11-19 15:19:18 +11:00
md/raid6: avoid data corruption during recovery of double-degraded RAID6
2014-08-18 14:49:46 +10:00
raid5: add an option to avoid copy data from bio to stripe cache
2014-05-29 16:59:47 +10:00
md/raid10: always initialise ->state on newly allocated r10_bio
2014-08-19 17:20:27 +10:00
40aa978ecc