diff --git a/archive/archive.go b/archive/archive.go
index 078aa6d354..5d29ce8193 100644
--- a/archive/archive.go
+++ b/archive/archive.go
@@ -303,8 +303,11 @@ func escapeName(name string) string {
 	return string(escaped)
 }
 
-// Tar creates an archive from the directory at `path`, only including files whose relative
-// paths are included in `filter`. If `filter` is nil, then all files are included.
+// TarFilter creates an archive from the directory at `srcPath` with `options`, and returns it as a
+// stream of bytes.
+//
+// Files are included according to `options.Includes`, default to including all files.
+// Stream is compressed according to `options.Compression', default to Uncompressed.
 func TarFilter(srcPath string, options *TarOptions) (io.ReadCloser, error) {
 	pipeReader, pipeWriter := io.Pipe()