Commit fe630de0 authored by Vitaly Mayatskikh's avatar Vitaly Mayatskikh Committed by Song Liu
Browse files

md/raid10: avoid deadlock on recovery. 



When disk failure happens and the array has a spare drive, resync thread
kicks in and starts to refill the spare. However it may get blocked by
a retry thread that resubmits failed IO to a mirror and itself can get
blocked on a barrier raised by the resync thread.

Acked-by: default avatarNigel Croxon <ncroxon@redhat.com>
Signed-off-by: default avatarVitaly Mayatskikh <vmayatskikh@digitalocean.com>
Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
parent c333f949

drivers/md/raid10.c

+11 −3
Original line number Diff line number Diff line
@@ -980,6 +980,7 @@ static void wait_barrier(struct r10conf *conf) 
{

	spin_lock_irq(&conf->resync_lock);

	if (conf->barrier) {

		struct bio_list *bio_list = current->bio_list;

		conf->nr_waiting++;

		/* Wait for the barrier to drop.

		 * However if there are already pending
@@ -994,9 +995,16 @@ static void wait_barrier(struct r10conf *conf) 
		wait_event_lock_irq(conf->wait_barrier,

				    !conf->barrier ||

				    (atomic_read(&conf->nr_pending) &&

				     current->bio_list &&

				     (!bio_list_empty(&current->bio_list[0]) ||

				      !bio_list_empty(&current->bio_list[1]))),

				     bio_list &&

				     (!bio_list_empty(&bio_list[0]) ||

				      !bio_list_empty(&bio_list[1]))) ||

				     /* move on if recovery thread is

				      * blocked by us

				      */

				     (conf->mddev->thread->tsk == current &&

				      test_bit(MD_RECOVERY_RUNNING,

					       &conf->mddev->recovery) &&

				      conf->nr_queued > 0),

				    conf->resync_lock);

		conf->nr_waiting--;

		if (!conf->nr_waiting)