From: NeilBrown <neilb@suse.de>
Date: Mon, 22 Sep 2014 00:06:23 +0000 (+1000)
Subject: md/raid1: intialise start_next_window for READ case to avoid hang
X-Git-Tag: v3.14.20~19
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=2d433af81cb56603d8541dfe118bb02c69570d6c;p=platform%2Fkernel%2Flinux-stable.git

md/raid1: intialise start_next_window for READ case to avoid hang

commit f0cc9a057151892b885be21a1d19b0185568281d upstream.

r1_bio->start_next_window is not initialised in the READ
case, so allow_barrier may incorrectly decrement
   conf->current_window_requests
which can cause raise_barrier() to block forever.

Fixes: 79ef3a8aa1cb1523cc231c9a90a278333c21f761
Reported-by: Brassow Jonathan <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 665f887567f1..55de4f6f7eaf 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1185,6 +1185,7 @@ read_again:
 				   atomic_read(&bitmap->behind_writes) == 0);
 		}
 		r1_bio->read_disk = rdisk;
+		r1_bio->start_next_window = 0;
 
 		read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
 		bio_trim(read_bio, r1_bio->sector - bio->bi_iter.bi_sector,