[ 131/187] md/raid5: In ops_run_io, inc nr_pending before calling md_wait_for_blocked_rdev

Greg Kroah-Hartman
2012-07-12T22:43:22Z

From: majianpeng <majianpeng@gmail.com>

commit 1850753d2e6d9ca7856581ca5d3cf09521e6a5d7 upstream.

In ops_run_io(), the call to md_wait_for_blocked_rdev will decrement
nr_pending so we lose the reference we hold on the rdev.
So atomic_inc it first to maintain the reference.

This bug was introduced by commit 73e92e51b7969ef5477d
md/raid5. Don't write to known bad block on doubtful devices.

which appeared in 3.0, so patch is suitable for stable kernels since
then.

Signed-off-by: majianpeng <majianpeng@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/md/raid5.c | 6 ++++++
1 file changed, 6 insertions(+)

--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -583,6 +583,12 @@ static void ops_run_io(struct stripe_hea
* a chance*/
md_check_recovery(conf->mddev);
}
+ /*
+ * Because md_wait_for_blocked_rdev
+ * will dec nr_pending, we must
+ * increment it first.
+ */
+ atomic_inc(&rdev->nr_pending);
md_wait_for_blocked_rdev(rdev, conf->mddev);
} else {
/* Acknowledged bad block - skip the write */