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authorNeilBrown <neilb@suse.de>2013-02-25 12:38:29 +1100
committerNeilBrown <neilb@suse.de>2013-02-26 11:58:50 +1100
commitee0b0244030434cdda26777bfb98962447e080cd (patch)
treef2e59eeed60c0b76f6f53c63221114f2c0d3dbe2 /drivers/md
parentf96c9f305c24a0d4a075e2c75aa6b417aa238687 (diff)
downloadop-kernel-dev-ee0b0244030434cdda26777bfb98962447e080cd.zip
op-kernel-dev-ee0b0244030434cdda26777bfb98962447e080cd.tar.gz
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')
-rw-r--r--drivers/md/raid1.c1
-rw-r--r--drivers/md/raid10.c1
2 files changed, 2 insertions, 0 deletions
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 6e5d5a5..fd86b37 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;
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 61ed150..77b562d 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1119,6 +1119,7 @@ static void raid10_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;
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