diff --git a/volumes.c b/volumes.c
index 2e1fb4a4..1fda5946 100644
--- a/volumes.c
+++ b/volumes.c
@@ -450,7 +450,7 @@ out:
 	return ret;
 }
 
-int find_free_dev_extent(struct btrfs_trans_handle *trans,
+static int find_free_dev_extent(struct btrfs_trans_handle *trans,
 			 struct btrfs_device *device, u64 num_bytes,
 			 u64 *start)
 {