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a8d41b59f3
kernel-ark/drivers/md
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Mikulas Patocka a8d41b59f3 dm snapshot: fix race during exception creation 
Fix a race condition that returns incorrect data when a write causes an
exception to be allocated whilst a read is still in flight.

The race condition happens as follows:
* A read to non-reallocated sector in the snapshot is submitted so that the
  read is routed to the original device.
* A write to the original device is submitted. The write causes an exception
  that reallocates the block.  The write proceeds.
* The original read is dequeued and reads the wrong data.

This race can be triggered with CFQ scheduler and one thread writing and
multiple threads reading simultaneously.

(This patch relies upon the earlier dm-kcopyd-per-device.patch to avoid a
deadlock.)

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2008-07-21 12:00:34 +01:00
..
raid6test md: raid6: clean up the style of raid6test/test.c 2008-02-06 10:41:18 -08:00
.gitignore gitignore: misc files 2006-01-01 22:21:50 +01:00
bitmap.c md: kill file_path wrapper 2008-05-24 09:56:09 -07:00
dm-bio-list.h dm: bio_list macro renaming 2007-10-20 02:01:11 +01:00
dm-bio-record.h
dm-crypt.c dm crypt: use cond_resched 2008-07-02 09:34:28 +01:00
dm-delay.c dm: bio_list macro renaming 2007-10-20 02:01:11 +01:00
dm-exception-store.c dm: move include files 2008-04-25 13:26:55 +01:00
dm-io.c dm: unplug queues in threads 2008-04-25 13:26:57 +01:00
dm-ioctl.c dm ioctl: use uninitialized_var 2008-02-08 02:10:16 +00:00
dm-kcopyd.c dm: unplug queues in threads 2008-04-25 13:26:57 +01:00
dm-linear.c [PATCH] dm: map and endio symbolic return codes 2006-12-08 08:29:09 -08:00
dm-log.c dm log: make dm_dirty_log init and exit static 2008-07-21 12:00:27 +01:00
dm-mpath.c dm mpath: fix test for reinstate_path 2008-07-21 12:00:31 +01:00
dm-mpath.h [SCSI] scsi_dh: Remove hardware handler infrastructure from dm 2008-06-05 09:23:42 -05:00
dm-path-selector.c dm: use kzalloc 2007-10-20 02:01:07 +01:00
dm-path-selector.h [PATCH] struct path: rename DM's struct path 2006-12-08 08:28:40 -08:00
dm-raid1.c dm: unplug queues in threads 2008-04-25 13:26:57 +01:00
dm-round-robin.c dm: remove duplicate module name from error msgs 2007-07-12 15:01:08 -07:00
dm-snap.c dm snapshot: fix race during exception creation 2008-07-21 12:00:34 +01:00
dm-snap.h dm snapshot: track snapshot reads 2008-07-21 12:00:32 +01:00
dm-stripe.c dm: stripe enhanced status return 2008-02-08 02:11:24 +00:00
dm-table.c dm: use unlocked variants of queue flag check/set 2008-04-29 10:21:12 -07:00
dm-target.c dm: use kzalloc 2007-10-20 02:01:07 +01:00
dm-uevent.c md: replace remaining __FUNCTION__ occurrences 2008-04-28 08:58:42 -07:00
dm-uevent.h dm: uevent generate events 2007-10-20 02:01:26 +01:00
dm-zero.c Drop 'size' argument from bio_endio and bi_end_io 2007-10-10 09:25:57 +02:00
dm.c dm io: remove struct padding 2008-07-21 12:00:28 +01:00
dm.h dm log: make dm_dirty_log init and exit static 2008-07-21 12:00:27 +01:00
faulty.c md: change ITERATE_RDEV to rdev_for_each 2008-02-06 10:41:19 -08:00
Kconfig [SCSI] scsi_dh: fix kconfig related build errors 2008-07-15 09:16:43 -05:00
linear.c Add bvec_merge_data to handle stacked devices and ->merge_bvec() 2008-07-03 13:21:15 +02:00
Makefile [SCSI] scsi_dh: Remove hardware handler infrastructure from dm 2008-06-05 09:23:42 -05:00
md.c Fix error paths if md_probe fails. 2008-06-28 08:31:17 +10:00
mktables.c md: raid6: Fix mktable.c 2008-02-06 10:41:18 -08:00
multipath.c md: restart recovery cleanly after device failure. 2008-05-24 09:56:10 -07:00
raid0.c Add bvec_merge_data to handle stacked devices and ->merge_bvec() 2008-07-03 13:21:15 +02:00
raid1.c md: restart recovery cleanly after device failure. 2008-05-24 09:56:10 -07:00
raid5.c Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block 2008-07-14 13:15:14 -07:00
raid6.h
raid6algos.c drivers/md: use time_before, time_before_eq, etc 2008-04-28 08:58:42 -07:00
raid6altivec.uc
raid6int.uc
raid6mmx.c x86 merge fallout: uml 2007-10-29 07:41:32 -07:00
raid6recov.c
raid6sse1.c x86 merge fallout: uml 2007-10-29 07:41:32 -07:00
raid6sse2.c x86 merge fallout: uml 2007-10-29 07:41:32 -07:00
raid6x86.h x86 merge fallout: uml 2007-10-29 07:41:32 -07:00
raid10.c Add bvec_merge_data to handle stacked devices and ->merge_bvec() 2008-07-03 13:21:15 +02:00
unroll.pl