Btrfs: reference counts on data extents

Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
index ad2d375..1b2c5e0 100644
--- a/fs/btrfs/inode-map.c
+++ b/fs/btrfs/inode-map.c
@@ -25,6 +25,7 @@
 	if (fs_root->fs_info->last_inode_alloc_dirid == dirid)
 		search_start = fs_root->fs_info->last_inode_alloc;
 
+	search_start = max(search_start, BTRFS_FIRST_FREE_OBJECTID);
 	search_key.objectid = search_start;
 	search_key.flags = 0;
 	btrfs_set_key_type(&search_key, BTRFS_INODE_MAP_ITEM_KEY);