dm cache: fix a race condition between queuing new migrations and quiescing for a shutdown

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The code that was trying to do this was inadequate.  The postsuspend
method (in ioctl context), needs to wait for the worker thread to
acknowledge the request to quiesce.  Otherwise the migration count may
drop to zero temporarily before the worker thread realises we're
quiescing.  In this case the target will be taken down, but the worker
thread may have issued a new migration, which will cause an oops when
it completes.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 3.9+

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Joe Thornber 2013-10-30 17:11:58 +00:00 • committed by Mike Snitzer

parent f8e5f01a32

commit 66cb1910df

1 changed files with 40 additions and 14 deletions

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74

drivers/md/dm-cache-target.c

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