From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kara Subject: Re: [PATCH 1/4] ext4: Fix fsync error handling after filesysteb abort. Date: Tue, 21 May 2013 18:18:50 +0200 Message-ID: <20130521161850.GE11616@quack.suse.cz> References: <1368707290-26185-1-git-send-email-dmonakhov@openvz.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org To: Dmitry Monakhov Return-path: Received: from cantor2.suse.de ([195.135.220.15]:36648 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754272Ab3EUQSy (ORCPT ); Tue, 21 May 2013 12:18:54 -0400 Content-Disposition: inline In-Reply-To: <1368707290-26185-1-git-send-email-dmonakhov@openvz.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Thu 16-05-13 16:28:07, Dmitry Monakhov wrote: The patch looks OK but I have some typo fixes below. But you can add Reviewed-by: Jan Kara > If filesystem was aborted after inode's write back complete ^^ is > but before it's metadata was updated we may return success ^^^ its > due to (sb->s_flags & MS_RDONLY) which is incorrect and > result in data loss. ^^^ results > 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 > --- > 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 */ ^^^ sure > + 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 ^^^ sure visible ^^ > + * 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 > + ^^ Stray empty line. > * 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 ^^ sure visible ^^ > + * 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); -- Jan Kara SUSE Labs, CR