tree 2fa2f90642cc55502a2f827620d6fd60a6f3e589
parent 89bfce763e43fa4897e0d3af6b29ed909df64cfd
author Bart Van Assche <bart.vanassche@sandisk.com> 1493313075 -0700
committer Mike Snitzer <snitzer@redhat.com> 1493327067 -0400

dm mpath: avoid that path removal can trigger an infinite loop

If blk_get_request() fails, check whether the failure is due to a path
being removed.  If that is the case, fail the path by triggering a call
to fail_path().  This avoids that the following scenario can be
encountered while removing paths:
* CPU usage of a kworker thread jumps to 100%.
* Removing the DM device becomes impossible.

Delay requeueing if blk_get_request() returns -EBUSY or -EWOULDBLOCK,
and the queue is not dying, because in these cases immediate requeuing
is inappropriate.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>