diff --git a/lib/fluent/plugin/in_diskusage.rb b/lib/fluent/plugin/in_diskusage.rb
index 32fd7ca..3aff232 100644
--- a/lib/fluent/plugin/in_diskusage.rb
+++ b/lib/fluent/plugin/in_diskusage.rb
@@ -1,3 +1,5 @@
+require 'fluent/input'
+
 class Fluent::DiskUsage < Fluent::Input
 	Fluent::Plugin.register_input('diskusage',self)
 
@@ -48,6 +50,6 @@ def output
 	def shutdown
 		@watcher.terminate
 		@watcher.join
-
+		super
 	end
 end