From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754969Ab2GIOv1 (ORCPT ); Mon, 9 Jul 2012 10:51:27 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:38099 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754306Ab2GIOh6 (ORCPT ); Mon, 9 Jul 2012 10:37:58 -0400 Message-Id: <20120709143119.018962208@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Mon, 09 Jul 2012 15:31:32 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, majianpeng , NeilBrown Subject: [ 16/48] md/raid5: In ops_run_io, inc nr_pending before calling md_wait_for_blocked_rdev In-Reply-To: <20120709143116.348975190@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: majianpeng 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 Signed-off-by: NeilBrown Signed-off-by: Ben Hutchings --- drivers/md/raid5.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 9567a9c..befadb4 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 */