Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757681AbaJCWNE (ORCPT ); Fri, 3 Oct 2014 18:13:04 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:46624 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757521AbaJCWGF (ORCPT ); Fri, 3 Oct 2014 18:06:05 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, majianpeng , NeilBrown Subject: [PATCH 3.16 331/357] md/raid1: make sure resync waits for conflicting writes to complete. Date: Fri, 3 Oct 2014 14:31:57 -0700 Message-Id: <20141003212943.403555416@linuxfoundation.org> X-Mailer: git-send-email 2.1.2 In-Reply-To: <20141003212933.458851516@linuxfoundation.org> References: <20141003212933.458851516@linuxfoundation.org> User-Agent: quilt/0.63-1 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 3.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: NeilBrown commit 2f73d3c55d09ce60647b96ad2a9b539c95a530ee upstream. The resync/recovery process for raid1 was recently changed so that writes could happen in parallel with resync providing they were in different regions of the device. There is a problem though: While a write request will always wait for conflicting resync to complete, a resync request will *not* always wait for conflicting writes to complete. Two changes are needed to fix this: 1/ raise_barrier (which waits until it is safe to do resync) must wait until current_window_requests is zero 2/ wait_battier (which waits at the start of a new write request) must update current_window_requests if the request could possible conflict with a concurrent resync. As concurrent writes and resync can lead to data loss, this patch is suitable for -stable. Fixes: 79ef3a8aa1cb1523cc231c9a90a278333c21f761 Cc: majianpeng Signed-off-by: NeilBrown Signed-off-by: Greg Kroah-Hartman --- drivers/md/raid1.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -845,10 +845,12 @@ static void raise_barrier(struct r1conf * C: next_resync + RESYNC_SECTORS > start_next_window, meaning * next resync will reach to the window which normal bios are * handling. + * D: while there are any active requests in the current window. */ wait_event_lock_irq(conf->wait_barrier, !conf->array_frozen && conf->barrier < RESYNC_DEPTH && + conf->current_window_requests == 0 && (conf->start_next_window >= conf->next_resync + RESYNC_SECTORS), conf->resync_lock); @@ -915,8 +917,8 @@ static sector_t wait_barrier(struct r1co } if (bio && bio_data_dir(bio) == WRITE) { - if (conf->next_resync + NEXT_NORMALIO_DISTANCE - <= bio->bi_iter.bi_sector) { + if (bio->bi_iter.bi_sector >= + conf->next_resync) { if (conf->start_next_window == MaxSector) conf->start_next_window = conf->next_resync + -- 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/