Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964844AbaBDWdN (ORCPT ); Tue, 4 Feb 2014 17:33:13 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:56485 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933239AbaBDVH5 (ORCPT ); Tue, 4 Feb 2014 16:07:57 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ethan Wilson , NeilBrown Subject: [PATCH 3.12 002/133] md/raid5: fix long-standing problem with bitmap handling on write failure. Date: Tue, 4 Feb 2014 13:06:43 -0800 Message-Id: <20140204210737.081042417@linuxfoundation.org> X-Mailer: git-send-email 1.8.5.1.163.gd7aced9 In-Reply-To: <20140204210737.008598235@linuxfoundation.org> References: <20140204210737.008598235@linuxfoundation.org> User-Agent: quilt/0.61-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: NeilBrown commit 9f97e4b128d2ea90a5f5063ea0ee3b0911f4c669 upstream. Before a write starts we set a bit in the write-intent bitmap. When the write completes we clear that bit if the write was successful to all devices. However if the write wasn't fully successful we should not clear the bit. If the faulty drive is subsequently re-added, the fact that the bit is still set ensure that we will re-write the data that is missing. This logic is mediated by the STRIPE_DEGRADED flag - we only clear the bitmap bit when this flag is not set. Currently we correctly set the flag if a write starts when some devices are failed or missing. But we do *not* set the flag if some device failed during the write attempt. This is wrong and can result in clearing the bit inappropriately. So: set the flag when a write fails. This bug has been present since bitmaps were introduces, so the fix is suitable for any -stable kernel. Reported-by: Ethan Wilson Signed-off-by: NeilBrown Signed-off-by: Greg Kroah-Hartman --- drivers/md/raid5.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -2004,6 +2004,7 @@ static void raid5_end_write_request(stru set_bit(R5_MadeGoodRepl, &sh->dev[i].flags); } else { if (!uptodate) { + set_bit(STRIPE_DEGRADED, &sh->state); set_bit(WriteErrorSeen, &rdev->flags); set_bit(R5_WriteError, &sh->dev[i].flags); if (!test_and_set_bit(WantReplacement, &rdev->flags)) -- 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/