From: akpm@linux-foundation.org Subject: - ext3-wait-on-all-pending-commits-in-ext3_sync_fs.patch removed from -mm tree Date: Mon, 10 Nov 2008 12:32:44 -0800 Message-ID: <200811102032.mAAKWi9j024095@imap1.linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org To: ajones@riverbed.com, linux-ext4@vger.kernel.org, sandeen@redhat.com, stable@kernel.org, tytso@mit.edu, mm-commits@vger.kernel.org Return-path: Sender: mm-commits-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org The patch titled ext3: wait on all pending commits in ext3_sync_fs has been removed from the -mm tree. Its filename was ext3-wait-on-all-pending-commits-in-ext3_sync_fs.patch This patch was dropped because it was merged into mainline or a subsystem tree The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: ext3: wait on all pending commits in ext3_sync_fs From: Arthur Jones In ext3_sync_fs, we only wait for a commit to finish if we started it, but there may be one already in progress which will not be synced. In the case of a data=ordered umount with pending long symlinks which are delayed due to a long list of other I/O on the backing block device, this causes the buffer associated with the long symlinks to not be moved to the inode dirty list in the second phase of fsync_super. Then, before they can be dirtied again, kjournald exits, seeing the UMOUNT flag and the dirty pages are never written to the backing block device, causing long symlink corruption and exposing new or previously freed block data to userspace. This can be reproduced with a script created by Eric Sandeen : #!/bin/bash umount /mnt/test2 mount /dev/sdb4 /mnt/test2 rm -f /mnt/test2/* dd if=/dev/zero of=/mnt/test2/bigfile bs=1M count=512 touch /mnt/test2/thisisveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryverylongfilename ln -s /mnt/test2/thisisveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryverylongfilename /mnt/test2/link umount /mnt/test2 mount /dev/sdb4 /mnt/test2 ls /mnt/test2/ umount /mnt/test2 To ensure all commits are synced, we flush all journal commits now when sync_fs'ing ext3. Signed-off-by: Arthur Jones Cc: Eric Sandeen Cc: Theodore Ts'o Cc: Cc: [2.6.everything] Signed-off-by: Andrew Morton --- fs/ext3/super.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff -puN fs/ext3/super.c~ext3-wait-on-all-pending-commits-in-ext3_sync_fs fs/ext3/super.c --- a/fs/ext3/super.c~ext3-wait-on-all-pending-commits-in-ext3_sync_fs +++ a/fs/ext3/super.c @@ -2390,13 +2390,12 @@ static void ext3_write_super (struct sup static int ext3_sync_fs(struct super_block *sb, int wait) { - tid_t target;