From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933888AbbCDGWI (ORCPT ); Wed, 4 Mar 2015 01:22:08 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:43928 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933844AbbCDGV7 (ORCPT ); Wed, 4 Mar 2015 01:21:59 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Manibalan P , Jes Sorensen , NeilBrown Subject: [PATCH 3.19 156/175] md/raid5: Fix livelock when array is both resyncing and degraded. Date: Tue, 3 Mar 2015 22:15:34 -0800 Message-Id: <20150304061051.697641882@linuxfoundation.org> X-Mailer: git-send-email 2.3.1 In-Reply-To: <20150304061026.134125919@linuxfoundation.org> References: <20150304061026.134125919@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: NeilBrown commit 26ac107378c4742978216be1005b7291b799c7b2 upstream. Commit a7854487cd7128a30a7f4f5259de9f67d5efb95f: md: When RAID5 is dirty, force reconstruct-write instead of read-modify-write. Causes an RCW cycle to be forced even when the array is degraded. A degraded array cannot support RCW as that requires reading all data blocks, and one may be missing. Forcing an RCW when it is not possible causes a live-lock and the code spins, repeatedly deciding to do something that cannot succeed. So change the condition to only force RCW on non-degraded arrays. Reported-by: Manibalan P Bisected-by: Jes Sorensen Tested-by: Jes Sorensen Signed-off-by: NeilBrown Fixes: a7854487cd7128a30a7f4f5259de9f67d5efb95f Signed-off-by: Greg Kroah-Hartman --- drivers/md/raid5.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -3102,7 +3102,8 @@ static void handle_stripe_dirtying(struc * generate correct data from the parity. */ if (conf->max_degraded == 2 || - (recovery_cp < MaxSector && sh->sector >= recovery_cp)) { + (recovery_cp < MaxSector && sh->sector >= recovery_cp && + s->failed == 0)) { /* Calculate the real rcw later - for now make it * look like rcw is cheaper */