From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754643Ab1BFXq3 (ORCPT ); Sun, 6 Feb 2011 18:46:29 -0500 Received: from 1wt.eu ([62.212.114.60]:60326 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754626Ab1BFXq1 (ORCPT ); Sun, 6 Feb 2011 18:46:27 -0500 Message-Id: <20110206232252.997683635@pcw.home.local> User-Agent: quilt/0.48-1 Date: Mon, 07 Feb 2011 00:23:03 +0100 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@kernel.org, stable-review@kernel.org Cc: NeilBrown , Greg Kroah-Hartman , Willy Tarreau Subject: [PATCH 11/23] md: fix bug with re-adding of partially recovered device. In-Reply-To: <4beed4da27f06efb2c13d6ed48850634@local> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.27.58-stable review patch. If anyone has any objections, please let us know. ------------------ From: NeilBrown commit 1a855a0606653d2d82506281e2c686bacb4b2f45 upstream. With v0.90 metadata, a hot-spare does not become a full member of the array until recovery is complete. So if we re-add such a device to the array, we know that all of it is as up-to-date as the event count would suggest, and so it a bitmap-based recovery is possible. However with v1.x metadata, the hot-spare immediately becomes a full member of the array, but it record how much of the device has been recovered. If the array is stopped and re-assembled recovery starts from this point. When such a device is hot-added to an array we currently lose the 'how much is recovered' information and incorrectly included it as a full in-sync member (after bitmap-based fixup). This is wrong and unsafe and could corrupt data. So be more careful about setting saved_raid_disk - which is what guides the re-adding of devices back into an array. The new code matches the code in slot_store which does a similar thing, which is encouraging. This is suitable for any -stable kernel. Reported-by: "Dailey, Nate" Signed-off-by: NeilBrown Signed-off-by: Greg Kroah-Hartman Signed-off-by: Willy Tarreau --- drivers/md/md.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) Index: longterm-2.6.27/drivers/md/md.c =================================================================== --- longterm-2.6.27.orig/drivers/md/md.c 2011-01-29 11:19:14.697066081 +0100 +++ longterm-2.6.27/drivers/md/md.c 2011-01-29 11:27:14.692063986 +0100 @@ -4300,7 +4300,7 @@ PTR_ERR(rdev)); return PTR_ERR(rdev); } - /* set save_raid_disk if appropriate */ + /* set saved_raid_disk if appropriate */ if (!mddev->persistent) { if (info->state & (1<raid_disk < mddev->raid_disks) @@ -4310,7 +4310,10 @@ } else super_types[mddev->major_version]. validate_super(mddev, rdev); - rdev->saved_raid_disk = rdev->raid_disk; + if (test_bit(In_sync, &rdev->flags)) + rdev->saved_raid_disk = rdev->raid_disk; + else + rdev->saved_raid_disk = -1; clear_bit(In_sync, &rdev->flags); /* just to be sure */ if (info->state & (1<