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: v3.17-rc7~21^2~7
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=f0cc9a057151892b885be21a1d19b0185568281d;p=uclinux-h8%2Flinux.git

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

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
cc: stable@vger.kernel.org (v3.13+)
Reported-by: Brassow Jonathan <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
---

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index d7690f86fdb9..9ebccf624571 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1186,6 +1186,7 @@ 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,