From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754600AbbCaUCd (ORCPT ); Tue, 31 Mar 2015 16:02:33 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:39537 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753428AbbCaTuE (ORCPT ); Tue, 31 Mar 2015 15:50:04 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: NeilBrown , Kamal Mostafa Subject: [PATCH 3.13.y-ckt 112/143] md/raid5: Fix livelock when array is both resyncing and degraded. Date: Tue, 31 Mar 2015 12:47:57 -0700 Message-Id: <1427831308-1854-113-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1427831308-1854-1-git-send-email-kamal@canonical.com> References: <1427831308-1854-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.13.11-ckt18 -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: Kamal Mostafa --- drivers/md/raid5.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 3782c2f..dcdc327 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -3079,7 +3079,8 @@ static void handle_stripe_dirtying(struct r5conf *conf, * 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 */ -- 1.9.1