Btrfs: Force f_pos to the max when a readdir hits the end of the directory.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 16d3aef..026bc9c 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1430,7 +1430,7 @@
 			di = (struct btrfs_dir_item *)((char *)di + di_len);
 		}
 	}
-	filp->f_pos++;
+	filp->f_pos = INT_LIMIT(typeof(filp->f_pos));
 nopos:
 	ret = 0;
 err: