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authormajianpeng <majianpeng@gmail.com>2012-07-03 12:11:54 +1000
committerNeilBrown <neilb@suse.de>2012-07-03 12:11:54 +1000
commit1850753d2e6d9ca7856581ca5d3cf09521e6a5d7 (patch)
tree78b6a6f246d35b13c3a37461187be7453d0972ba
parent6c0544e255dd6582a9899572e120fb55d9f672a4 (diff)
downloadlinux-1850753d2e6d9ca7856581ca5d3cf09521e6a5d7.tar.gz
md/raid5: In ops_run_io, inc nr_pending before calling md_wait_for_blocked_rdev
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.

Cc: stable@vger.kernel.org
Signed-off-by: majianpeng <majianpeng@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
-rw-r--r--drivers/md/raid5.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 9567a9c83a1f..befadb41a11f 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -606,6 +606,12 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
 					 * 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 */