diff options
| author |   NeilBrown <neilb@suse.com> | 2015-07-27 11:48:52 +1000 |
|---|---|---|
| committer | NeilBrown <neilb@suse.com> | 2015-08-03 12:29:42 +1000 |
| commit | 423f04d63cf421ea436bcc5be02543d549ce4b28 (patch) | |
| tree | 0d98d3b3de62c7689fbe58a6229c7d760d998c55 /drivers/md | |
| parent | Linux 4.2-rc5 (diff) | |
| download | linux-dev-423f04d63cf421ea436bcc5be02543d549ce4b28.tar.xz linux-dev-423f04d63cf421ea436bcc5be02543d549ce4b28.zip | |
md/raid1: extend spinlock to protect raid1_end_read_request against inconsistencies
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.")
Cc: stable@vger.kernel.org (v3.0+)
Signed-off-by: NeilBrown <neilb@suse.com>
Diffstat (limited to 'drivers/md')
| -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 94f5b55069e0..967a4ed73929 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -1476,6 +1476,7 @@ 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 @@ -1495,14 +1496,13 @@ 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. */ @@ -1568,7 +1568,10 @@ 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; struct md_rdev *repl = conf->mirrors[conf->raid_disks + i].rdev; @@ -1599,7 +1602,6 @@ 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); |