From c04be0aa82ff535e3676ab3e573957bdeef41879 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Tue, 3 Oct 2006 01:15:53 -0700 Subject: [PATCH] md: Improve locking around error handling The error handling routines don't use proper locking, and so two concurrent errors could trigger a problem. So: - use test-and-set and test-and-clear to synchonise the In_sync bits with the ->degraded count - use the spinlock to protect updates to the degraded count (could use an atomic_t but that would be a bigger change in code, and isn't really justified) - remove un-necessary locking in raid5 Signed-off-by: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/md/raid5.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) (limited to 'drivers/md/raid5.c') diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 46fd651539fe..6cea9c9a98e2 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -636,7 +636,6 @@ static int raid5_end_write_request (struct bio *bi, unsigned int bytes_done, struct stripe_head *sh = bi->bi_private; raid5_conf_t *conf = sh->raid_conf; int disks = sh->disks, i; - unsigned long flags; int uptodate = test_bit(BIO_UPTODATE, &bi->bi_flags); if (bi->bi_size) @@ -654,7 +653,6 @@ static int raid5_end_write_request (struct bio *bi, unsigned int bytes_done, return 0; } - spin_lock_irqsave(&conf->device_lock, flags); if (!uptodate) md_error(conf->mddev, conf->disks[i].rdev); @@ -662,8 +660,7 @@ static int raid5_end_write_request (struct bio *bi, unsigned int bytes_done, clear_bit(R5_LOCKED, &sh->dev[i].flags); set_bit(STRIPE_HANDLE, &sh->state); - __release_stripe(conf, sh); - spin_unlock_irqrestore(&conf->device_lock, flags); + release_stripe(sh); return 0; } @@ -697,9 +694,11 @@ static void error(mddev_t *mddev, mdk_rdev_t *rdev) if (!test_bit(Faulty, &rdev->flags)) { set_bit(MD_CHANGE_DEVS, &mddev->flags); - if (test_bit(In_sync, &rdev->flags)) { + if (test_and_clear_bit(In_sync, &rdev->flags)) { + unsigned long flags; + spin_lock_irqsave(&conf->device_lock, flags); mddev->degraded++; - clear_bit(In_sync, &rdev->flags); + spin_unlock_irqrestore(&conf->device_lock, flags); /* * if recovery was running, make sure it aborts. */ @@ -3418,9 +3417,11 @@ static int raid5_spare_active(mddev_t *mddev) tmp = conf->disks + i; if (tmp->rdev && !test_bit(Faulty, &tmp->rdev->flags) - && !test_bit(In_sync, &tmp->rdev->flags)) { + && !test_and_set_bit(In_sync, &tmp->rdev->flags)) { + unsigned long flags; + spin_lock_irqsave(&conf->device_lock, flags); mddev->degraded--; - set_bit(In_sync, &tmp->rdev->flags); + spin_unlock_irqrestore(&conf->device_lock, flags); } } print_raid5_conf(conf); @@ -3556,6 +3557,7 @@ static int raid5_start_reshape(mddev_t *mddev) struct list_head *rtmp; int spares = 0; int added_devices = 0; + unsigned long flags; if (mddev->degraded || test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) @@ -3597,7 +3599,9 @@ static int raid5_start_reshape(mddev_t *mddev) break; } + spin_lock_irqsave(&conf->device_lock, flags); mddev->degraded = (conf->raid_disks - conf->previous_raid_disks) - added_devices; + spin_unlock_irqrestore(&conf->device_lock, flags); mddev->raid_disks = conf->raid_disks; mddev->reshape_position = 0; set_bit(MD_CHANGE_DEVS, &mddev->flags); -- cgit v1.2.3