diff --git a/weed/filer2/cassandra/cassandra_store.go b/weed/filer2/cassandra/cassandra_store.go
index 40f371e2f..4d845c2fa 100644
--- a/weed/filer2/cassandra/cassandra_store.go
+++ b/weed/filer2/cassandra/cassandra_store.go
@@ -126,7 +126,7 @@ func (store *CassandraStore) DeleteFolderChildren(ctx context.Context, fullpath
 }
 
 func (store *CassandraStore) ListDirectoryPrefixedEntries(ctx context.Context, fullpath util.FullPath, startFileName string, inclusive bool, limit int, prefix string) (entries []*filer2.Entry, err error) {
-	return nil, filer2.UnsupportedListDirectoryPrefixedErr
+	return nil, filer2.ErrUnsupportedListDirectoryPrefixed
 }
 
 func (store *CassandraStore) ListDirectoryEntries(ctx context.Context, fullpath util.FullPath, startFileName string, inclusive bool,
diff --git a/weed/filer2/etcd/etcd_store.go b/weed/filer2/etcd/etcd_store.go
index d0b1ff202..6f4c3ce5c 100644
--- a/weed/filer2/etcd/etcd_store.go
+++ b/weed/filer2/etcd/etcd_store.go
@@ -136,7 +136,7 @@ func (store *EtcdStore) DeleteFolderChildren(ctx context.Context, fullpath weed_
 }
 
 func (store *EtcdStore) ListDirectoryPrefixedEntries(ctx context.Context, fullpath weed_util.FullPath, startFileName string, inclusive bool, limit int, prefix string) (entries []*filer2.Entry, err error) {
-	return nil, filer2.UnsupportedListDirectoryPrefixedErr
+	return nil, filer2.ErrUnsupportedListDirectoryPrefixed
 }
 
 func (store *EtcdStore) ListDirectoryEntries(ctx context.Context, fullpath weed_util.FullPath, startFileName string, inclusive bool, limit int) (entries []*filer2.Entry, err error) {
diff --git a/weed/filer2/filer.go b/weed/filer2/filer.go
index 603e51fa2..9d485ad8a 100644
--- a/weed/filer2/filer.go
+++ b/weed/filer2/filer.go
@@ -24,7 +24,7 @@ const PaginationSize = 1024 * 256
 var (
 	OS_UID                              = uint32(os.Getuid())
 	OS_GID                              = uint32(os.Getgid())
-	UnsupportedListDirectoryPrefixedErr = errors.New("UNSUPPORTED")
+	ErrUnsupportedListDirectoryPrefixed = errors.New("UNSUPPORTED")
 )
 
 type Filer struct {
diff --git a/weed/filer2/filerstore.go b/weed/filer2/filerstore.go
index 642ebb3c8..b55aeb4d6 100644
--- a/weed/filer2/filerstore.go
+++ b/weed/filer2/filerstore.go
@@ -138,7 +138,7 @@ func (fsw *FilerStoreWrapper) ListDirectoryPrefixedEntries(ctx context.Context,
 		stats.FilerStoreHistogram.WithLabelValues(fsw.ActualStore.GetName(), "list").Observe(time.Since(start).Seconds())
 	}()
 	entries, err := fsw.ActualStore.ListDirectoryPrefixedEntries(ctx, dirPath, startFileName, includeStartFile, limit, prefix)
-	if err.Error() == UnsupportedListDirectoryPrefixedErr.Error() {
+	if err.Error() == ErrUnsupportedListDirectoryPrefixed.Error() {
 		count := 0
 		notPrefixed, err := fsw.ActualStore.ListDirectoryEntries(ctx, dirPath, startFileName, includeStartFile, limit)
 		if err != nil {
diff --git a/weed/filer2/leveldb/leveldb_store.go b/weed/filer2/leveldb/leveldb_store.go
index 2ea88635b..1c08d2831 100644
--- a/weed/filer2/leveldb/leveldb_store.go
+++ b/weed/filer2/leveldb/leveldb_store.go
@@ -159,7 +159,7 @@ func (store *LevelDBStore) DeleteFolderChildren(ctx context.Context, fullpath we
 }
 
 func (store *LevelDBStore) ListDirectoryPrefixedEntries(ctx context.Context, fullpath weed_util.FullPath, startFileName string, inclusive bool, limit int, prefix string) (entries []*filer2.Entry, err error) {
-	return nil, filer2.UnsupportedListDirectoryPrefixedErr
+	return nil, filer2.ErrUnsupportedListDirectoryPrefixed
 }
 
 func (store *LevelDBStore) ListDirectoryEntries(ctx context.Context, fullpath weed_util.FullPath, startFileName string, inclusive bool,
diff --git a/weed/filer2/leveldb2/leveldb2_store.go b/weed/filer2/leveldb2/leveldb2_store.go
index 2a9c2fe3f..ca9d6f04d 100644
--- a/weed/filer2/leveldb2/leveldb2_store.go
+++ b/weed/filer2/leveldb2/leveldb2_store.go
@@ -168,7 +168,7 @@ func (store *LevelDB2Store) DeleteFolderChildren(ctx context.Context, fullpath w
 }
 
 func (store *LevelDB2Store) ListDirectoryPrefixedEntries(ctx context.Context, fullpath weed_util.FullPath, startFileName string, inclusive bool, limit int, prefix string) (entries []*filer2.Entry, err error) {
-	return nil, filer2.UnsupportedListDirectoryPrefixedErr
+	return nil, filer2.ErrUnsupportedListDirectoryPrefixed
 }
 
 func (store *LevelDB2Store) ListDirectoryEntries(ctx context.Context, fullpath weed_util.FullPath, startFileName string, inclusive bool,
diff --git a/weed/filer2/mongodb/mongodb_store.go b/weed/filer2/mongodb/mongodb_store.go
index 080d6248f..661aa4ea0 100644
--- a/weed/filer2/mongodb/mongodb_store.go
+++ b/weed/filer2/mongodb/mongodb_store.go
@@ -168,7 +168,7 @@ func (store *MongodbStore) DeleteFolderChildren(ctx context.Context, fullpath ut
 }
 
 func (store *MongodbStore) ListDirectoryPrefixedEntries(ctx context.Context, fullpath util.FullPath, startFileName string, inclusive bool, limit int, prefix string) (entries []*filer2.Entry, err error) {
-	return nil, filer2.UnsupportedListDirectoryPrefixedErr
+	return nil, filer2.ErrUnsupportedListDirectoryPrefixed
 }
 
 func (store *MongodbStore) ListDirectoryEntries(ctx context.Context, fullpath util.FullPath, startFileName string, inclusive bool, limit int) (entries []*filer2.Entry, err error) {
diff --git a/weed/filer2/redis/universal_redis_store.go b/weed/filer2/redis/universal_redis_store.go
index 8cc70c72b..fc2abef6c 100644
--- a/weed/filer2/redis/universal_redis_store.go
+++ b/weed/filer2/redis/universal_redis_store.go
@@ -122,7 +122,7 @@ func (store *UniversalRedisStore) DeleteFolderChildren(ctx context.Context, full
 }
 
 func (store *UniversalRedisStore) ListDirectoryPrefixedEntries(ctx context.Context, fullpath util.FullPath, startFileName string, inclusive bool, limit int, prefix string) (entries []*filer2.Entry, err error) {
-	return nil, filer2.UnsupportedListDirectoryPrefixedErr
+	return nil, filer2.ErrUnsupportedListDirectoryPrefixed
 }
 
 func (store *UniversalRedisStore) ListDirectoryEntries(ctx context.Context, fullpath util.FullPath, startFileName string, inclusive bool,
diff --git a/weed/filer2/redis2/universal_redis_store.go b/weed/filer2/redis2/universal_redis_store.go
index 2ce7ebec7..c639635ef 100644
--- a/weed/filer2/redis2/universal_redis_store.go
+++ b/weed/filer2/redis2/universal_redis_store.go
@@ -117,7 +117,7 @@ func (store *UniversalRedis2Store) DeleteFolderChildren(ctx context.Context, ful
 }
 
 func (store *UniversalRedis2Store) ListDirectoryPrefixedEntries(ctx context.Context, fullpath util.FullPath, startFileName string, inclusive bool, limit int, prefix string) (entries []*filer2.Entry, err error) {
-	return nil, filer2.UnsupportedListDirectoryPrefixedErr
+	return nil, filer2.ErrUnsupportedListDirectoryPrefixed
 }
 
 func (store *UniversalRedis2Store) ListDirectoryEntries(ctx context.Context, fullpath util.FullPath, startFileName string, inclusive bool,