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/raid5.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) (limited to 'drivers/md/raid5.c') diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 968dacaced6..087eee0cb80 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -2607,6 +2607,7 @@ static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh, } } + /* * handle_stripe - do things to a stripe. * @@ -2632,6 +2633,7 @@ static void handle_stripe5(struct stripe_head *sh) struct stripe_head_state s; struct r5dev *dev; unsigned long pending = 0; + mdk_rdev_t *blocked_rdev = NULL; memset(&s, 0, sizeof(s)); pr_debug("handling stripe %llu, state=%#lx cnt=%d, pd_idx=%d " @@ -2691,6 +2693,11 @@ static void handle_stripe5(struct stripe_head *sh) if (dev->written) s.written++; rdev = rcu_dereference(conf->disks[i].rdev); + if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) { + blocked_rdev = rdev; + atomic_inc(&rdev->nr_pending); + break; + } if (!rdev || !test_bit(In_sync, &rdev->flags)) { /* The ReadError flag will just be confusing now */ clear_bit(R5_ReadError, &dev->flags); @@ -2705,6 +2712,11 @@ static void handle_stripe5(struct stripe_head *sh) } rcu_read_unlock(); + if (unlikely(blocked_rdev)) { + set_bit(STRIPE_HANDLE, &sh->state); + goto unlock; + } + if (s.to_fill && !test_and_set_bit(STRIPE_OP_BIOFILL, &sh->ops.pending)) sh->ops.count++; @@ -2894,8 +2906,13 @@ static void handle_stripe5(struct stripe_head *sh) if (sh->ops.count) pending = get_stripe_work(sh); + unlock: spin_unlock(&sh->lock); + /* wait for this device to become unblocked */ + if (unlikely(blocked_rdev)) + md_wait_for_blocked_rdev(blocked_rdev, conf->mddev); + if (pending) raid5_run_ops(sh, pending); @@ -2912,6 +2929,7 @@ static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page) struct stripe_head_state s; struct r6_state r6s; struct r5dev *dev, *pdev, *qdev; + mdk_rdev_t *blocked_rdev = NULL; r6s.qd_idx = raid6_next_disk(pd_idx, disks); pr_debug("handling stripe %llu, state=%#lx cnt=%d, " @@ -2975,6 +2993,11 @@ static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page) if (dev->written) s.written++; rdev = rcu_dereference(conf->disks[i].rdev); + if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) { + blocked_rdev = rdev; + atomic_inc(&rdev->nr_pending); + break; + } if (!rdev || !test_bit(In_sync, &rdev->flags)) { /* The ReadError flag will just be confusing now */ clear_bit(R5_ReadError, &dev->flags); @@ -2989,6 +3012,11 @@ static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page) set_bit(R5_Insync, &dev->flags); } rcu_read_unlock(); + + if (unlikely(blocked_rdev)) { + set_bit(STRIPE_HANDLE, &sh->state); + goto unlock; + } pr_debug("locked=%d uptodate=%d to_read=%d" " to_write=%d failed=%d failed_num=%d,%d\n", s.locked, s.uptodate, s.to_read, s.to_write, s.failed, @@ -3094,8 +3122,13 @@ static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page) !test_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending)) handle_stripe_expansion(conf, sh, &r6s); + unlock: spin_unlock(&sh->lock); + /* wait for this device to become unblocked */ + if (unlikely(blocked_rdev)) + md_wait_for_blocked_rdev(blocked_rdev, conf->mddev); + return_io(return_bi); for (i=disks; i-- ;) { -- cgit v1.2.3