[XFS] Clear XBF_READ_AHEAD flag on I/O completion.

SGI-PV: 972554
SGI-Modid: xfs-linux-melb:xfs-kern:30128a

Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>

fs/xfs/linux-2.6/xfs_buf.c

@@ -1025,7 +1025,7 @@ xfs_buf_ioend(
 	xfs_buf_t		*bp,
 	int			schedule)
 {
-	bp->b_flags &= ~(XBF_READ | XBF_WRITE);
+	bp->b_flags &= ~(XBF_READ | XBF_WRITE | XBF_READ_AHEAD);
 	if (bp->b_error == 0)
 		bp->b_flags |= XBF_DONE;