[XFS] When issuing metadata readahead, submit bio with READA not READ.

SGI-PV: 944409
SGI-Modid: xfs-linux-melb:xfs-kern:26603a

Signed-off-by: Nathan Scott <nathans@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>
1 file changed