diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 96427b1ecac3..b7b49b4eb68d 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2766,12 +2766,11 @@ static int unpin_extent_range(struct btrfs_fs_info *fs_info,
 		spin_unlock(&cache->lock);
 		if (!readonly && return_free_space &&
 		    global_rsv->space_info == space_info) {
-			u64 to_add = len;
-
 			spin_lock(&global_rsv->lock);
 			if (!global_rsv->full) {
-				to_add = min(len, global_rsv->size -
-					     global_rsv->reserved);
+				u64 to_add = min(len, global_rsv->size -
+						      global_rsv->reserved);
+
 				global_rsv->reserved += to_add;
 				btrfs_space_info_update_bytes_may_use(fs_info,
 						space_info, to_add);