diff --git a/go/filer/flat_namespace/flat_namespace_filer.go b/go/filer/flat_namespace/flat_namespace_filer.go
index 9959b2924..2a2fd657b 100644
--- a/go/filer/flat_namespace/flat_namespace_filer.go
+++ b/go/filer/flat_namespace/flat_namespace_filer.go
@@ -29,16 +29,16 @@ func (filer *FlatNamespaceFiler) FindFile(fullFileName string) (fid string, err
 	return filer.store.Get(fullFileName)
 }
 func (filer *FlatNamespaceFiler) FindDirectory(dirPath string) (dirId filer.DirectoryId, err error) {
-	return 0, ErrNotImplemented
+	return filer.store.FindDirectory(dirPath)
 }
 func (filer *FlatNamespaceFiler) ListDirectories(dirPath string) (dirs []filer.DirectoryEntry, err error) {
-	return nil, ErrNotImplemented
+	return filer.store.ListDirectories(dirPath)
 }
 func (filer *FlatNamespaceFiler) ListFiles(dirPath string, lastFileName string, limit int) (files []filer.FileEntry, err error) {
-	return nil, ErrNotImplemented
+	return filer.store.ListFiles(dirPath, lastFileName, limit)
 }
 func (filer *FlatNamespaceFiler) DeleteDirectory(dirPath string, recursive bool) (err error) {
-	return ErrNotImplemented
+	return filer.store.DeleteDirectory(dirPath, recursive)
 }
 
 func (filer *FlatNamespaceFiler) DeleteFile(fullFileName string) (fid string, err error) {
@@ -46,5 +46,5 @@ func (filer *FlatNamespaceFiler) DeleteFile(fullFileName string) (fid string, er
 }
 
 func (filer *FlatNamespaceFiler) Move(fromPath string, toPath string) error {
-	return ErrNotImplemented
+	return filer.store.Move(fromPath, toPath)
 }
diff --git a/go/filer/flat_namespace/flat_namespace_store.go b/go/filer/flat_namespace/flat_namespace_store.go
index 832b70e40..8bb0d0a13 100644
--- a/go/filer/flat_namespace/flat_namespace_store.go
+++ b/go/filer/flat_namespace/flat_namespace_store.go
@@ -1,9 +1,16 @@
 package flat_namespace
 
-import ()
+import "github.com/chrislusf/seaweedfs/go/filer"
 
 type FlatNamespaceStore interface {
 	Put(fullFileName string, fid string) (err error)
 	Get(fullFileName string) (fid string, err error)
 	Delete(fullFileName string) (fid string, err error)
+
+	//redis store support these functions
+	FindDirectory(dirPath string) (dirId filer.DirectoryId, err error)
+	ListDirectories(dirPath string) (dirs []filer.DirectoryEntry, err error)
+	ListFiles(dirPath string, lastFileName string, limit int) (files []filer.FileEntry, err error)
+	DeleteDirectory(dirPath string, recursive bool) (err error)
+	Move(fromPath string, toPath string) error
 }