Btrfs: extent_map optimizations to cut down on CPU usage

Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index f691542..54a5d00 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -463,6 +463,7 @@
 static int check_block(struct btrfs_root *root, struct btrfs_path *path,
 			int level)
 {
+	return 0;
 #if 0
 	struct extent_buffer *buf = path->nodes[level];