Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932216AbbBSOFt (ORCPT ); Thu, 19 Feb 2015 09:05:49 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:39162 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753487AbbBSNwM (ORCPT ); Thu, 19 Feb 2015 08:52:12 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: NeilBrown , Luis Henriques Subject: [PATCH 3.16.y-ckt 14/58] md/raid5: fix another livelock caused by non-aligned writes. Date: Thu, 19 Feb 2015 13:51:44 +0000 Message-Id: <1424353948-31863-15-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1424353948-31863-1-git-send-email-luis.henriques@canonical.com> References: <1424353948-31863-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2041 Lines: 61 3.16.7-ckt7 -stable review patch. If anyone has any objections, please let me know. ------------------ From: NeilBrown commit b1b02fe97f75b12ab34b2303bfd4e3526d903a58 upstream. If a non-page-aligned write is destined for a device which is missing/faulty, we can deadlock. As the target device is missing, a read-modify-write cycle is not possible. As the write is not for a full-page, a recontruct-write cycle is not possible. This should be handled by logic in fetch_block() which notices there is a non-R5_OVERWRITE write to a missing device, and so loads all blocks. However since commit 67f455486d2ea2, that code requires STRIPE_PREREAD_ACTIVE before it will active, and those circumstances never set STRIPE_PREREAD_ACTIVE. So: in handle_stripe_dirtying, if neither rmw or rcw was possible, set STRIPE_DELAYED, which will cause STRIPE_PREREAD_ACTIVE be set after a suitable delay. Fixes: 67f455486d2ea20b2d94d6adf5b9b783d079e321 Reported-by: Mikulas Patocka Tested-by: Heinz Mauelshagen Signed-off-by: NeilBrown Signed-off-by: Luis Henriques --- drivers/md/raid5.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 222aa7521877..68a03d7f25ee 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -3204,6 +3204,11 @@ static void handle_stripe_dirtying(struct r5conf *conf, (unsigned long long)sh->sector, rcw, qread, test_bit(STRIPE_DELAYED, &sh->state)); } + + if (rcw > disks && rmw > disks && + !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) + set_bit(STRIPE_DELAYED, &sh->state); + /* now if nothing is locked, and if we have enough data, * we can start a write request */ -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/