Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754482AbbEGK1M (ORCPT ); Thu, 7 May 2015 06:27:12 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:47741 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752347AbbEGJsJ (ORCPT ); Thu, 7 May 2015 05:48:09 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Filipe Manana , Chris Mason , Luis Henriques Subject: [PATCH 3.16.y-ckt 082/180] Btrfs: fix log tree corruption when fs mounted with -o discard Date: Thu, 7 May 2015 10:44:51 +0100 Message-Id: <1430991989-23170-83-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1430991989-23170-1-git-send-email-luis.henriques@canonical.com> References: <1430991989-23170-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2684 Lines: 62 3.16.7-ckt11 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Filipe Manana commit dcc82f4783ad91d4ab654f89f37ae9291cdc846a upstream. While committing a transaction we free the log roots before we write the new super block. Freeing the log roots implies marking the disk location of every node/leaf (metadata extent) as pinned before the new super block is written. This is to prevent the disk location of log metadata extents from being reused before the new super block is written, otherwise we would have a corrupted log tree if before the new super block is written a crash/reboot happens and the location of any log tree metadata extent ended up being reused and rewritten. Even though we pinned the log tree's metadata extents, we were issuing a discard against them if the fs was mounted with the -o discard option, resulting in corruption of the log tree if a crash/reboot happened before writing the new super block - the next time the fs was mounted, during the log replay process we would find nodes/leafs of the log btree with a content full of zeroes, causing the process to fail and require the use of the tool btrfs-zero-log to wipeout the log tree (and all data previously fsynced becoming lost forever). Fix this by not doing a discard when pinning an extent. The discard will be done later when it's safe (after the new super block is committed) at extent-tree.c:btrfs_finish_extent_commit(). Fixes: e688b7252f78 (Btrfs: fix extent pinning bugs in the tree log) Signed-off-by: Filipe Manana Signed-off-by: Chris Mason Signed-off-by: Luis Henriques --- fs/btrfs/extent-tree.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 58f014a2bba1..b6f19735d6a8 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -6971,12 +6971,11 @@ static int __btrfs_free_reserved_extent(struct btrfs_root *root, return -ENOSPC; } - if (btrfs_test_opt(root, DISCARD)) - ret = btrfs_discard_extent(root, start, len, NULL); - if (pin) pin_down_extent(root, cache, start, len, 1); else { + if (btrfs_test_opt(root, DISCARD)) + ret = btrfs_discard_extent(root, start, len, NULL); btrfs_add_free_space(cache, start, len); btrfs_update_reserved_bytes(cache, len, RESERVE_FREE, delalloc); } -- 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/