xfs: scrub directory metadata

Scrub the hash tree and all the entries in a directory.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 6526ef0..1814687 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -984,7 +984,7 @@ xfs_file_readdir(
 	 * point we can change the ->readdir prototype to include the
 	 * buffer size.  For now we use the current glibc buffer size.
 	 */
-	bufsize = (size_t)min_t(loff_t, 32768, ip->i_d.di_size);
+	bufsize = (size_t)min_t(loff_t, XFS_READDIR_BUFSIZE, ip->i_d.di_size);
 
 	return xfs_readdir(NULL, ip, ctx, bufsize);
 }