verlap
  and they are both the same type.

SGI-PV: 968555
SGI-Modid: xfs-linux-melb:xfs-kern:29311a

Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>