From: NeilBrown Date: Mon, 1 May 2006 19:15:47 +0000 (-0700) Subject: [PATCH] md: Fix 'rdev->nr_pending' count when retrying barrier requests X-Git-Tag: v2.6.17-rc4~95 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=5e7dd2ab6b9bdfa60e19b8739e6b2a204fd4f477;p=linux-2.6-omap-h63xx.git [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: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index b8c13c897cc..4070eff6f0f 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -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);