During regular VM shutdown, the VM should sync() anyway. (And admin.vm.volume.Import does fdatasync(), which is also fine.) But let's be extra careful.
@@ -230,6 +230,7 @@ class ReflinkVolume(qubes.storage.Volume):
def _commit(self, path_from):
self._add_revision()
self._prune_revisions()
+ _fsync_path(path_from)
_rename_file(path_from, self._path_clean)
def _add_revision(self):