diff --git a/libfuse/lib/fuse_cfg.cpp b/libfuse/lib/fuse_cfg.cpp
index 0bd93f94..3d1151b2 100644
--- a/libfuse/lib/fuse_cfg.cpp
+++ b/libfuse/lib/fuse_cfg.cpp
@@ -13,3 +13,9 @@ fuse_cfg_t::valid_gid() const
 {
   return (gid != FUSE_CFG_INVALID_ID);
 }
+
+bool
+fuse_cfg_t::valid_umask() const
+{
+  return (umask != FUSE_CFG_INVALID_ID);
+}