From 6bfe0b499082fd3950429017cd8ebf2a6c458aa5 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Wed, 30 Apr 2008 00:52:32 -0700 Subject: md: support blocking writes to an array on device failure Allows a userspace metadata handler to take action upon detecting a device failure. Based on an original patch by Neil Brown. Changes: -added blocked_wait waitqueue to rdev -don't qualify Blocked with Faulty always let userspace block writes -added md_wait_for_blocked_rdev to wait for the block device to be clear, if userspace misses the notification another one is sent every 5 seconds -set MD_RECOVERY_NEEDED after clearing "blocked" -kill DoBlock flag, just test mddev->external Signed-off-by: Dan Williams Signed-off-by: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/md/raid1.c | 27 ++++++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-) (limited to 'drivers/md/raid1.c') diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 9fd473a6dbf5..6778b7cb39bd 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -773,7 +773,6 @@ static int make_request(struct request_queue *q, struct bio * bio) r1bio_t *r1_bio; struct bio *read_bio; int i, targets = 0, disks; - mdk_rdev_t *rdev; struct bitmap *bitmap = mddev->bitmap; unsigned long flags; struct bio_list bl; @@ -781,6 +780,7 @@ static int make_request(struct request_queue *q, struct bio * bio) const int rw = bio_data_dir(bio); const int do_sync = bio_sync(bio); int do_barriers; + mdk_rdev_t *blocked_rdev; /* * Register the new request and wait if the reconstruction @@ -862,10 +862,17 @@ static int make_request(struct request_queue *q, struct bio * bio) first = 0; } #endif + retry_write: + blocked_rdev = NULL; rcu_read_lock(); for (i = 0; i < disks; i++) { - if ((rdev=rcu_dereference(conf->mirrors[i].rdev)) != NULL && - !test_bit(Faulty, &rdev->flags)) { + mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev); + if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) { + atomic_inc(&rdev->nr_pending); + blocked_rdev = rdev; + break; + } + if (rdev && !test_bit(Faulty, &rdev->flags)) { atomic_inc(&rdev->nr_pending); if (test_bit(Faulty, &rdev->flags)) { rdev_dec_pending(rdev, mddev); @@ -878,6 +885,20 @@ static int make_request(struct request_queue *q, struct bio * bio) } rcu_read_unlock(); + if (unlikely(blocked_rdev)) { + /* Wait for this device to become unblocked */ + int j; + + for (j = 0; j < i; j++) + if (r1_bio->bios[j]) + rdev_dec_pending(conf->mirrors[j].rdev, mddev); + + allow_barrier(conf); + md_wait_for_blocked_rdev(blocked_rdev, mddev); + wait_barrier(conf); + goto retry_write; + } + BUG_ON(targets == 0); /* we never fail the last device */ if (targets < conf->raid_disks) { -- cgit v1.2.3