diff options
author | NeilBrown <neilb@suse.com> | 2015-07-27 11:48:52 +1000 |
---|---|---|
committer | Ben Hutchings <ben@decadent.org.uk> | 2015-10-13 03:46:01 +0100 |
commit | 966b20a399e17a861527fb92b0411a5deb90ba18 (patch) | |
tree | 643879099699f529ca166abcd61a808cf874cf4c | |
parent | 1faeb78fa64ca582f3b4bb1d432564714431486a (diff) | |
download | kernel_samsung_smdk4412-966b20a399e17a861527fb92b0411a5deb90ba18.zip kernel_samsung_smdk4412-966b20a399e17a861527fb92b0411a5deb90ba18.tar.gz kernel_samsung_smdk4412-966b20a399e17a861527fb92b0411a5deb90ba18.tar.bz2 |
md/raid1: extend spinlock to protect raid1_end_read_request against inconsistencies
commit 423f04d63cf421ea436bcc5be02543d549ce4b28 upstream.
raid1_end_read_request() assumes that the In_sync bits are consistent
with the ->degaded count.
raid1_spare_active updates the In_sync bit before the ->degraded count
and so exposes an inconsistency, as does error()
So extend the spinlock in raid1_spare_active() and error() to hide those
inconsistencies.
This should probably be part of
Commit: 34cab6f42003 ("md/raid1: fix test for 'was read error from
last working device'.")
as it addresses the same issue. It fixes the same bug and should go
to -stable for same reasons.
Fixes: 76073054c95b ("md/raid1: clean up read_balance.")
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
-rw-r--r-- | drivers/md/raid1.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 6e7b002..a5f284d 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -1208,6 +1208,7 @@ static void error(struct mddev *mddev, struct md_rdev *rdev) { char b[BDEVNAME_SIZE]; struct r1conf *conf = mddev->private; + unsigned long flags; /* * If it is not operational, then we have already marked it as dead @@ -1227,14 +1228,13 @@ static void error(struct mddev *mddev, struct md_rdev *rdev) return; } set_bit(Blocked, &rdev->flags); + spin_lock_irqsave(&conf->device_lock, flags); if (test_and_clear_bit(In_sync, &rdev->flags)) { - unsigned long flags; - spin_lock_irqsave(&conf->device_lock, flags); mddev->degraded++; set_bit(Faulty, &rdev->flags); - spin_unlock_irqrestore(&conf->device_lock, flags); } else set_bit(Faulty, &rdev->flags); + spin_unlock_irqrestore(&conf->device_lock, flags); /* * if recovery is running, make sure it aborts. */ @@ -1292,7 +1292,10 @@ static int raid1_spare_active(struct mddev *mddev) * Find all failed disks within the RAID1 configuration * and mark them readable. * Called under mddev lock, so rcu protection not needed. + * device_lock used to avoid races with raid1_end_read_request + * which expects 'In_sync' flags and ->degraded to be consistent. */ + spin_lock_irqsave(&conf->device_lock, flags); for (i = 0; i < conf->raid_disks; i++) { struct md_rdev *rdev = conf->mirrors[i].rdev; if (rdev @@ -1302,7 +1305,6 @@ static int raid1_spare_active(struct mddev *mddev) sysfs_notify_dirent_safe(rdev->sysfs_state); } } - spin_lock_irqsave(&conf->device_lock, flags); mddev->degraded -= count; spin_unlock_irqrestore(&conf->device_lock, flags); |