From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from youngberry.canonical.com ([91.189.89.112]:48573 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753061AbbH0WMd (ORCPT ); Thu, 27 Aug 2015 18:12:33 -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 3.19.y-ckt 028/130] md/raid10: always set reshape_safe when initializing reshape_position. Date: Thu, 27 Aug 2015 15:10:19 -0700 Message-Id: <1440713521-5906-29-git-send-email-kamal@canonical.com> In-Reply-To: <1440713521-5906-1-git-send-email-kamal@canonical.com> References: <1440713521-5906-1-git-send-email-kamal@canonical.com> Sender: stable-owner@vger.kernel.org List-ID: 3.19.8-ckt6 -stable review patch. If anyone has any objections, please let me know. ------------------ From: NeilBrown commit 299b0685e31c9f3dcc2d58ee3beca761a40b44b3 upstream. 'reshape_position' tracks where in the reshape we have reached. 'reshape_safe' tracks where in the reshape we have safely recorded in the metadata. These are compared to determine when to update the metadata. So it is important that reshape_safe is initialised properly. Currently it isn't. When starting a reshape from the beginning it usually has the correct value by luck. But when reducing the number of devices in a RAID10, it has the wrong value and this leads to the metadata not being updated correctly. This can lead to corruption if the reshape is not allowed to complete. This patch is suitable for any -stable kernel which supports RAID10 reshape, which is 3.5 and later. Fixes: 3ea7daa5d7fd ("md/raid10: add reshape support") Signed-off-by: NeilBrown Signed-off-by: Kamal Mostafa --- drivers/md/raid10.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 32e282f..17eb767 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -3581,6 +3581,7 @@ static struct r10conf *setup_conf(struct mddev *mddev) /* far_copies must be 1 */ conf->prev.stride = conf->dev_sectors; } + conf->reshape_safe = conf->reshape_progress; spin_lock_init(&conf->device_lock); INIT_LIST_HEAD(&conf->retry_list); @@ -3788,7 +3789,6 @@ static int run(struct mddev *mddev) } conf->offset_diff = min_offset_diff; - conf->reshape_safe = conf->reshape_progress; clear_bit(MD_RECOVERY_SYNC, &mddev->recovery); clear_bit(MD_RECOVERY_CHECK, &mddev->recovery); set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery); @@ -4135,6 +4135,7 @@ static int raid10_start_reshape(struct mddev *mddev) conf->reshape_progress = size; } else conf->reshape_progress = 0; + conf->reshape_safe = conf->reshape_progress; spin_unlock_irq(&conf->device_lock); if (mddev->delta_disks && mddev->bitmap) { @@ -4201,6 +4202,7 @@ abort: rdev->new_data_offset = rdev->data_offset; smp_wmb(); conf->reshape_progress = MaxSector; + conf->reshape_safe = MaxSector; mddev->reshape_position = MaxSector; spin_unlock_irq(&conf->device_lock); return ret; @@ -4555,6 +4557,7 @@ static void end_reshape(struct r10conf *conf) md_finish_reshape(conf->mddev); smp_wmb(); conf->reshape_progress = MaxSector; + conf->reshape_safe = MaxSector; spin_unlock_irq(&conf->device_lock); /* read-ahead size must cover two whole stripes, which is -- 1.9.1