data=writeback mode is dangerous as it leads to higher data loss and stale data
exposure when systems crash. It should not be the default, especially when all
major distros ensure their ext3 filesystems default to ordered mode. Change the
default mode to the safer data=ordered mode, because we should be caring far
more about avoiding stale data exposure than performance.

CC: linux-ext4@vger.kernel.org
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Acked-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>