From patchwork Mon Feb 25 16:07:39 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Monakhov X-Patchwork-Id: 222953 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 8B6472C02C7 for ; Tue, 26 Feb 2013 03:08:59 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759952Ab3BYQI6 (ORCPT ); Mon, 25 Feb 2013 11:08:58 -0500 Received: from mailhub.sw.ru ([195.214.232.25]:9550 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759943Ab3BYQI4 (ORCPT ); Mon, 25 Feb 2013 11:08:56 -0500 Received: from mct-mail.qa.sw.ru ([10.29.1.112]) by relay.sw.ru (8.13.4/8.13.4) with ESMTP id r1PG7jt4007503; Mon, 25 Feb 2013 20:07:48 +0400 (MSK) From: Dmitry Monakhov To: linux-ext4@vger.kernel.org Cc: tytso@mit.edu, jack@suse.cz, wenqing.lz@taobao.com, Dmitry Monakhov Subject: [PATCH 1/5] ext4: ext4_split_extent shoult take care about extent zeroout v3 Date: Mon, 25 Feb 2013 20:07:39 +0400 Message-Id: <1361808463-25471-1-git-send-email-dmonakhov@openvz.org> X-Mailer: git-send-email 1.7.7.6 Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org When ext4_split_extent_at() ends up doing zeroout & conversion to initialized instead of split & conversion, ext4_split_extent() gets confused and can wrongly mark the extent back as uninitialized resulting in end IO code getting confused from large unwritten extents and may result in data loss. The example of problematic behavior is: lblk len lblk len ext4_split_extent() (ex=[1000,30,uninit], map=[1010,10]) ext4_split_extent_at() (split [1000,30,uninit] at 1020) ext4_ext_insert_extent() -> ENOSPC ext4_ext_zeroout() -> extent [1000,30] is now initialized ext4_split_extent_at() (split [1000,30,init] at 1010, MARK_UNINIT1 | MARK_UNINIT2) -> extent is split and parts marked as uninitialized Fix the problem by rechecking extent type after the first ext4_split_extent_at() returns. None of split_flags can not be applied to initialized extent so this patch also add BUG_ON to prevent similar issues in future. TESTCASE: https://github.com/dmonakhov/xfstests/commit/b8a55eb5ce28c6ff29e620ab090902fcd5833597 Changes since V2: Patch no longer depends on Jan's "disable-uninit-ext-mergring" patch. Signed-off-by: Dmitry Monakhov Reviewed-by: Jan Kara --- fs/ext4/extents.c | 22 ++++++++++++++++------ 1 files changed, 16 insertions(+), 6 deletions(-) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 372b2cb..3bd3ca5 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -2943,6 +2943,10 @@ static int ext4_split_extent_at(handle_t *handle, newblock = split - ee_block + ext4_ext_pblock(ex); BUG_ON(split < ee_block || split >= (ee_block + ee_len)); + BUG_ON(!ext4_ext_is_uninitialized(ex) && + split_flag & (EXT4_EXT_MAY_ZEROOUT | + EXT4_EXT_MARK_UNINIT1 | + EXT4_EXT_MARK_UNINIT2)); err = ext4_ext_get_access(handle, inode, path + depth); if (err) @@ -3061,19 +3065,25 @@ static int ext4_split_extent(handle_t *handle, if (err) goto out; } - + /* + * Update path is required because previous ext4_split_extent_at() may + * result in split of original leaf or extent zeroout. + */ ext4_ext_drop_refs(path); path = ext4_ext_find_extent(inode, map->m_lblk, path); if (IS_ERR(path)) return PTR_ERR(path); + depth = ext_depth(inode); + ex = path[depth].p_ext; + uninitialized = ext4_ext_is_uninitialized(ex); + split_flag1 = 0; if (map->m_lblk >= ee_block) { - split_flag1 = split_flag & (EXT4_EXT_MAY_ZEROOUT | - EXT4_EXT_DATA_VALID2); - if (uninitialized) + split_flag1 = split_flag & EXT4_EXT_DATA_VALID2; + if (uninitialized) { split_flag1 |= EXT4_EXT_MARK_UNINIT1; - if (split_flag & EXT4_EXT_MARK_UNINIT2) - split_flag1 |= EXT4_EXT_MARK_UNINIT2; + split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT | EXT4_EXT_MARK_UNINIT2); + } err = ext4_split_extent_at(handle, inode, path, map->m_lblk, split_flag1, flags); if (err)