diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 9bcb3570750e..1aee51a9f3bf 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -757,12 +757,14 @@ static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 }
 
 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;
@@ -2063,7 +2065,7 @@ int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 	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;
 }
@@ -7189,7 +7191,7 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
 	}
 out:
 	if (pin)
-		add_pinned_bytes(fs_info, &generic_ref);
+		add_pinned_bytes(fs_info, &generic_ref, 1);
 
 	if (last_ref) {
 		/*
@@ -7237,7 +7239,7 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_ref *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;
 }