Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753183AbcDRKth (ORCPT ); Mon, 18 Apr 2016 06:49:37 -0400 Received: from mail.kernel.org ([198.145.29.136]:34694 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752063AbcDRKte (ORCPT ); Mon, 18 Apr 2016 06:49:34 -0400 From: lizf@kernel.org To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, NeilBrown , Zefan Li Subject: [PATCH 3.4 46/92] md/raid10: don't clear bitmap bit when bad-block-list write fails. Date: Mon, 18 Apr 2016 18:45:51 +0800 Message-Id: <1460976397-5688-46-git-send-email-lizf@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1460976338-5631-1-git-send-email-lizf@kernel.org> References: <1460976338-5631-1-git-send-email-lizf@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3388 Lines: 97 From: NeilBrown 3.4.112-rc1 review patch. If anyone has any objections, please let me know. ------------------ commit c340702ca26a628832fade4f133d8160a55c29cc upstream. When a write fails and a bad-block-list is present, we can update the bad-block-list instead of writing the data. If this succeeds then it is OK clear the relevant bitmap-bit as no further 'sync' of the block is needed. However if writing the bad-block-list fails then we need to treat the write as failed and particularly must not clear the bitmap bit. Otherwise the device can be re-added (after any hardware connection issues are resolved) and because the relevant bit in the bitmap is clear, that block will not be resynced. This leads to data corruption. We already delay the final bio_endio() on the write until the bad-block-list is written so that when the write returns: either that data is safe, the bad-block record is safe, or the fact that the device is faulty is safe. However we *don't* delay the clearing of the bitmap, so the bitmap bit can be recorded as cleared before we know if the bad-block-list was written safely. So: delay that until the write really is safe. i.e. move the call to close_write() until just before calling bio_endio(), and recheck the 'is array degraded' status before making that call. This bug goes back to v3.1 when bad-block-lists were introduced, though it only affects arrays created with mdadm-3.3 or later as only those have bad-block lists. Backports will require at least Commit: 95af587e95aa ("md/raid10: ensure device failure recorded before write request returns.") as well. I'll send that to 'stable' separately. Note that of the two tests of R10BIO_WriteError that this patch adds, the first is certain to fail and the second is certain to succeed. However doing it this way makes the patch more obviously correct. I will tidy the code up in a future merge window. Reported-by: Nate Dailey Fixes: bd870a16c594 ("md/raid10: Handle write errors by updating badblock log.") Signed-off-by: NeilBrown Signed-off-by: Zefan Li --- drivers/md/raid10.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index b0ad772..1b77980 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -2568,16 +2568,17 @@ static void handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio) rdev_dec_pending(rdev, conf->mddev); } } - if (test_bit(R10BIO_WriteError, - &r10_bio->state)) - close_write(r10_bio); if (fail) { spin_lock_irq(&conf->device_lock); list_add(&r10_bio->retry_list, &conf->bio_end_io_list); spin_unlock_irq(&conf->device_lock); md_wakeup_thread(conf->mddev->thread); - } else + } else { + if (test_bit(R10BIO_WriteError, + &r10_bio->state)) + close_write(r10_bio); raid_end_bio_io(r10_bio); + } } } @@ -2604,6 +2605,12 @@ static void raid10d(struct mddev *mddev) r10_bio = list_first_entry(&conf->bio_end_io_list, struct r10bio, retry_list); list_del(&r10_bio->retry_list); + if (mddev->degraded) + set_bit(R10BIO_Degraded, &r10_bio->state); + + if (test_bit(R10BIO_WriteError, + &r10_bio->state)) + close_write(r10_bio); raid_end_bio_io(r10_bio); } } -- 1.9.1