Hi,
This is a patch set to fix deadlock on suspending of mirror device.
ISSUE
=====
Suspend procedure on a dm-mirror device could cause deadlock on recovery_count
semaphore.
When mirror_presuspend is called, recovery_count semaphore is acquired in
dm_rh_stop_recovery() to stop recovery routine, but when an signal is caught
in dm_wait_for_completion() or an error occurred in in dm_suspend(),
the suspend process is interrupted without releasing recovery_count semaphore
of a mirror device. This means that another suspend is executed, and then
the suspend process gets stuck at dm_rh_stop_recovery().
When suspend procedure is interrupted, the device should work properly since
the status of the device is not "suspended."
SOLUTION
========
Introduce a target handler, cancel_presuspend, to cancel status changes
done by a target specific presuspend handler.
PATCH SET
=========
1/3: dm: introduce cancel_presuspend framework
2/3: dm-raid1: add cancel_presuspend function
3/3: dm-delay: add cancel_presuspend function
I appreciate your comments.
Thanks,
--
Takahiro Yasui
Hitachi Computer Products (America), Inc.
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