diff --git a/kmod/src/forest.h b/kmod/src/forest.h
index 30564a11..24753e89 100644
--- a/kmod/src/forest.h
+++ b/kmod/src/forest.h
@@ -4,6 +4,7 @@
 struct scoutfs_alloc;
 struct scoutfs_block_writer;
 struct scoutfs_block;
+struct scoutfs_lock;
 
 #include "btree.h"