diff --git a/pkg/schema/filewriter.go b/pkg/schema/filewriter.go
index e764c133e..1a56fd990 100644
--- a/pkg/schema/filewriter.go
+++ b/pkg/schema/filewriter.go
@@ -241,7 +241,7 @@ func WriteFileMapRolling(bs blobserver.StatReceiver, fileMap Map, r io.Reader) (
 		}
 		m := fileMap
 		if isFragment {
-			m = NewBytes()
+			m = newBytes()
 		}
 		err = PopulateParts(m, fileSize, parts)
 		if err != nil {
diff --git a/pkg/schema/schema.go b/pkg/schema/schema.go
index c11691385..372a423ee 100644
--- a/pkg/schema/schema.go
+++ b/pkg/schema/schema.go
@@ -539,7 +539,7 @@ func PopulateSymlinkMap(m Map, fileName string) error {
 	return nil
 }
 
-func NewBytes() Map {
+func newBytes() Map {
 	return newMap(1, "bytes")
 }