}
 
 static void add_pinned_bytes(struct btrfs_fs_info *fs_info,
-                            struct btrfs_ref *ref)
+                            struct btrfs_ref *ref, int sign)
 {
        struct btrfs_space_info *space_info;
-       s64 num_bytes = -ref->len;
+       s64 num_bytes;
        u64 flags;
 
+       ASSERT(sign == 1 || sign == -1);
+       num_bytes = sign * ref->len;
        if (ref->type == BTRFS_REF_METADATA) {
                if (ref->tree_ref.root == BTRFS_CHUNK_TREE_OBJECTID)
                        flags = BTRFS_BLOCK_GROUP_SYSTEM;
        btrfs_ref_tree_mod(fs_info, generic_ref);
 
        if (ret == 0 && old_ref_mod < 0 && new_ref_mod >= 0)
-               add_pinned_bytes(fs_info, generic_ref);
+               add_pinned_bytes(fs_info, generic_ref, -1);
 
        return ret;
 }
        }
 out:
        if (pin)
-               add_pinned_bytes(fs_info, &generic_ref);
+               add_pinned_bytes(fs_info, &generic_ref, 1);
 
        if (last_ref) {
                /*
                btrfs_ref_tree_mod(fs_info, ref);
 
        if (ret == 0 && old_ref_mod >= 0 && new_ref_mod < 0)
-               add_pinned_bytes(fs_info, ref);
+               add_pinned_bytes(fs_info, ref, 1);
 
        return ret;
 }