From patchwork Thu May 16 12:28:07 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Monakhov X-Patchwork-Id: 244298 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 C503E2C00BD for ; Thu, 16 May 2013 22:28:20 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753565Ab3EPM2T (ORCPT ); Thu, 16 May 2013 08:28:19 -0400 Received: from mailhub.sw.ru ([195.214.232.25]:14337 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752197Ab3EPM2S (ORCPT ); Thu, 16 May 2013 08:28:18 -0400 Received: from mct-mail.qa.sw.ru ([10.29.1.112]) by relay.sw.ru (8.13.4/8.13.4) with ESMTP id r4GCSCa9020341; Thu, 16 May 2013 16:28:13 +0400 (MSK) From: Dmitry Monakhov Cc: linux-ext4@vger.kernel.org, Dmitry Monakhov Subject: [PATCH 1/4] ext4: Fix fsync error handling after filesysteb abort. Date: Thu, 16 May 2013 16:28:07 +0400 Message-Id: <1368707290-26185-1-git-send-email-dmonakhov@openvz.org> X-Mailer: git-send-email 1.7.7.6 To: unlisted-recipients:; (no To-header on input) Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org If filesystem was aborted after inode's write back complete but before it's metadata was updated we may return success due to (sb->s_flags & MS_RDONLY) which is incorrect and result in data loss. In order to handle fs abort correctly we have to check fs state once we discover that it is in MS_RDONLY state Test case: http://patchwork.ozlabs.org/patch/244297/ Signed-off-by: Dmitry Monakhov Reviewed-by: Jan Kara --- fs/ext4/fsync.c | 8 ++++++-- fs/ext4/super.c | 13 ++++++++++++- 2 files changed, 18 insertions(+), 3 deletions(-) diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c index e0ba8a4..d7df2f1 100644 --- a/fs/ext4/fsync.c +++ b/fs/ext4/fsync.c @@ -129,9 +129,13 @@ int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync) return ret; mutex_lock(&inode->i_mutex); - if (inode->i_sb->s_flags & MS_RDONLY) + if (inode->i_sb->s_flags & MS_RDONLY) { + /* Make shure that we read updated s_mount_flags value */ + smp_rmb(); + if (EXT4_SB(inode->i_sb)->s_mount_flags & EXT4_MF_FS_ABORTED) + ret = -EROFS; goto out; - + } ret = ext4_flush_unwritten_io(inode); if (ret < 0) goto out; diff --git a/fs/ext4/super.c b/fs/ext4/super.c index dbc7c09..6c91c8e 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -398,6 +398,11 @@ static void ext4_handle_error(struct super_block *sb) } if (test_opt(sb, ERRORS_RO)) { ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only"); + /* + * Make shure updated value of ->s_mount_flags will be visiable + * before ->s_flags update + */ + smp_wmb(); sb->s_flags |= MS_RDONLY; } if (test_opt(sb, ERRORS_PANIC)) @@ -552,6 +557,7 @@ void __ext4_std_error(struct super_block *sb, const char *function, * * We unconditionally force the filesystem into an ABORT|READONLY state, * unless the error response on the fs has been set to panic in which + * case we take the easy way out and panic immediately. */ @@ -570,8 +576,13 @@ void __ext4_abort(struct super_block *sb, const char *function, if ((sb->s_flags & MS_RDONLY) == 0) { ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only"); - sb->s_flags |= MS_RDONLY; EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED; + /* + * Make shure updated value of ->s_mount_flags will be visiable + * before ->s_flags update + */ + smp_wmb(); + sb->s_flags |= MS_RDONLY; if (EXT4_SB(sb)->s_journal) jbd2_journal_abort(EXT4_SB(sb)->s_journal, -EIO); save_error_info(sb, function, line);