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| author | NeilBrown <neilb@suse.de> | 2013-02-25 12:38:29 +1100 |
|---|---|---|
| committer | NeilBrown <neilb@suse.de> | 2013-02-26 11:58:50 +1100 |
| commit | ee0b0244030434cdda26777bfb98962447e080cd (patch) | |
| tree | f2e59eeed60c0b76f6f53c63221114f2c0d3dbe2 /drivers/md/raid1.c | |
| parent | f96c9f305c24a0d4a075e2c75aa6b417aa238687 (diff) | |
| download | lwn-ee0b0244030434cdda26777bfb98962447e080cd.tar.gz lwn-ee0b0244030434cdda26777bfb98962447e080cd.zip | |
md/raid1,raid10: fix deadlock with freeze_array()
When raid1/raid10 needs to fix a read error, it first drains
all pending requests by calling freeze_array().
This calls flush_pending_writes() if it needs to sleep,
but some writes may be pending in a per-process plug rather
than in the per-array request queue.
When raid1{,0}_unplug() moves the request from the per-process
plug to the per-array request queue (from which
flush_pending_writes() can flush them), it needs to wake up
freeze_array(), or freeze_array() will never flush them and so
it will block forever.
So add the requires wake_up() calls.
This bug was introduced by commit
f54a9d0e59c4bea3db733921ca9147612a6f292c
for raid1 and a similar commit for RAID10, and so has been present
since linux-3.6. As the bug causes a deadlock I believe this fix is
suitable for -stable.
Cc: stable@vger.kernel.org (3.6.y 3.7.y 3.8.y)
Reported-by: Tregaron Bayly <tbayly@bluehost.com>
Tested-by: Tregaron Bayly <tbayly@bluehost.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'drivers/md/raid1.c')
| -rw-r--r-- | drivers/md/raid1.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 6e5d5a5f9cb4..fd86b372692d 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -967,6 +967,7 @@ static void raid1_unplug(struct blk_plug_cb *cb, bool from_schedule) bio_list_merge(&conf->pending_bio_list, &plug->pending); conf->pending_count += plug->pending_cnt; spin_unlock_irq(&conf->device_lock); + wake_up(&conf->wait_barrier); md_wakeup_thread(mddev->thread); kfree(plug); return; |