Commit 5e7dd2ab authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds
Browse files

[PATCH] md: Fix 'rdev->nr_pending' count when retrying barrier requests 



When retrying a failed BIO_RW_BARRIER request, we need to keep the reference
in ->nr_pending over the whole retry.  Currently, we only hold the reference
if the failed request is the *last* one to finish - which is silly, because it
would normally be the first to finish.

So move the rdev_dec_pending call up into the didn't-fail branch.  As the rdev
isn't used in the later code, calling rdev_dec_pending earlier doesn't hurt.

Signed-off-by: default avatarNeil Brown <neilb@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 62de608d

drivers/md/raid1.c

+4 −5
Original line number Diff line number Diff line
@@ -319,6 +319,7 @@ static int raid1_end_write_request(struct bio *bio, unsigned int bytes_done, int 
		set_bit(BarriersNotsupp, &conf->mirrors[mirror].rdev->flags);

		set_bit(R1BIO_BarrierRetry, &r1_bio->state);

		r1_bio->mddev->barriers_work = 0;

		/* Don't rdev_dec_pending in this branch - keep it for the retry */

	} else {

		/*

		 * this branch is our 'one mirror IO has finished' event handler:
@@ -365,6 +366,7 @@ static int raid1_end_write_request(struct bio *bio, unsigned int bytes_done, int 
				}

			}

		}

		rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);

	}

	/*

	 *
@@ -374,11 +376,9 @@ static int raid1_end_write_request(struct bio *bio, unsigned int bytes_done, int 
	if (atomic_dec_and_test(&r1_bio->remaining)) {

		if (test_bit(R1BIO_BarrierRetry, &r1_bio->state)) {

			reschedule_retry(r1_bio);

			/* Don't dec_pending yet, we want to hold

			 * the reference over the retry

			 */

			goto out;

		}

		/* it really is the end of this request */

		if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {

			/* free extra copy of the data pages */

			int i = bio->bi_vcnt;
@@ -393,8 +393,6 @@ static int raid1_end_write_request(struct bio *bio, unsigned int bytes_done, int 
		md_write_end(r1_bio->mddev);

		raid_end_bio_io(r1_bio);

	}



	rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);

 out:

	if (to_put)

		bio_put(to_put);
@@ -1414,6 +1412,7 @@ static void raid1d(mddev_t *mddev) 
			 * Better resubmit without the barrier.

			 * We know which devices to resubmit for, because

			 * all others have had their bios[] entry cleared.

			 * We already have a nr_pending reference on these rdevs.

			 */

			int i;

			clear_bit(R1BIO_BarrierRetry, &r1_bio->state);

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