diff --git a/src/config.cpp b/src/config.cpp
index c8479e06..327e0281 100644
--- a/src/config.cpp
+++ b/src/config.cpp
@@ -144,6 +144,7 @@ Config::Config()
   xattr(XAttr::ENUM::PASSTHROUGH),
   _initialized(false)
 {
+  _map["foo"] = &foo;
   _map["allow-idmap"]            = &allow_idmap;
   _map["async_read"]             = &async_read;
   _map["auto_cache"]             = &auto_cache;