diff options
| author | Anssi Hannula <anssi.hannula@iki.fi> | 2014-08-01 11:55:47 -0400 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2014-08-01 12:25:22 -0400 |
| commit | 44fa816bb778edbab6b6ddaaf24908dd6295937e (patch) | |
| tree | 2b67384ea2670780a7215c593b08e2ec92bd27e6 /drivers/md/dm-io.c | |
| parent | d8c712ea471ce7a4fd1734ad2211adf8469ddddc (diff) | |
dm cache: fix race affecting dirty block count
nr_dirty is updated without locking, causing it to drift so that it is
non-zero (either a small positive integer, or a very large one when an
underflow occurs) even when there are no actual dirty blocks. This was
due to a race between the workqueue and map function accessing nr_dirty
in parallel without proper protection.
People were seeing under runs due to a race on increment/decrement of
nr_dirty, see: https://lkml.org/lkml/2014/6/3/648
Fix this by using an atomic_t for nr_dirty.
Reported-by: roma1390@gmail.com
Signed-off-by: Anssi Hannula <anssi.hannula@iki.fi>
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
Diffstat (limited to 'drivers/md/dm-io.c')
0 files changed, 0 insertions, 0 deletions