Fixes cross platform build failure

Closes #51358

pkg/volume/volume_linux.go

@@ -89,3 +89,17 @@ func SetVolumeOwnership(mounter Mounter, fsGroup *int64) error {
 		return nil
 	})
 }
+
+// IsSameFSGroup is called only for requests to mount an already mounted
+// volume. It checks if fsGroup of new mount request is the same or not.
+// It returns false if it not the same. It also returns current Gid of a path
+// provided for dir variable.
+func IsSameFSGroup(dir string, fsGroup int64) (bool, int, error) {
+	info, err := os.Stat(dir)
+	if err != nil {
+		glog.Errorf("Error getting stats for %s (%v)", dir, err)
+		return false, 0, err
+	}
+	s := info.Sys().(*syscall.Stat_t)
+	return int(s.Gid) == int(fsGroup), int(s.Gid), nil
+}