From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Monakhov Subject: [PATCH 5/6] ext4: Fix fsync error handling after filesystem abort. Date: Tue, 28 May 2013 13:19:00 +0400 Message-ID: <1369732741-26070-6-git-send-email-dmonakhov@openvz.org> References: <1369732741-26070-1-git-send-email-dmonakhov@openvz.org> Cc: jack@suse.cz, Dmitry Monakhov To: linux-ext4@vger.kernel.org Return-path: Received: from mailhub.sw.ru ([195.214.232.25]:1285 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933708Ab3E1JTQ (ORCPT ); Tue, 28 May 2013 05:19:16 -0400 In-Reply-To: <1369732741-26070-1-git-send-email-dmonakhov@openvz.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: If filesystem was aborted after inode's write back is complete but before its metadata was updated we may return success results 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 Changes from V1: - fix spelling Signed-off-by: Dmitry Monakhov --- fs/ext4/fsync.c | 8 ++++++-- fs/ext4/super.c | 12 +++++++++++- 2 files changed, 17 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 edc716d..b4154d3 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -399,6 +399,11 @@ 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)) @@ -571,8 +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); -- 1.7.1