• Theodore Ts'o's avatar
    ext4: wait on all pending commits in ext4_sync_fs() · 14ce0cb4
    Theodore Ts'o authored
    In ext4_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.
    
    To ensure all commits are synced, we flush all journal commits now
    when sync_fs'ing ext4.
    Signed-off-by: default avatarArthur Jones <ajones@riverbed.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
    Cc: Eric Sandeen <sandeen@redhat.com>
    Cc: <linux-ext4@vger.kernel.org>
    14ce0cb4
super.c 101 KB