code: def _reattach_linked_hdds(self):
          
  
          hdd_info_file = os.path.join(self.working_dir, self._vmname, "hdd_info.json")
          try:
              with open(hdd_info_file, "r", encoding="utf-8") as f:
                  hdd_table = json.load(f)
          except (ValueError, OSError) as e:
              # The VM has never be started
              return
  
          for hdd_info in hdd_table:
              hdd_file = os.path.join(self.working_dir, self._vmname, "Snapshots", hdd_info["hdd"])
              if os.path.exists(hdd_file):
                  log.info("VirtualBox VM '{name}' [{id}] attaching HDD {controller} {port} {device} {medium}".format(name=self.name,
                                                                                                                      id=self.id,
                                                                                                                      controller=hdd_info["controller"],
                                                                                                                      port=hdd_info["port"],
                                                                                                                      device=hdd_info["device"],
                                                                                                                      medium=hdd_file))
  
                  try:
                      yield from self._storage_attach('--storagectl "{}" --port {} --device {} --type hdd --medium "{}"'.format(hdd_info["controller"],
                                                                                                                                hdd_info["port"],
                                                                                                                                hdd_info["device"],
                                                                                                                                hdd_file))
  
                  except VirtualBoxError as e:
                      log.warn("VirtualBox VM '{name}' [{id}] error reattaching HDD {controller} {port} {device} {medium}: {error}".format(name=self.name,
                                                                                                                                           id=self.id,
                                                                                                                                           controller=hdd_info["controller"],
                                                                                                                                           port=hdd_info["port"],
                                                                                                                                           device=hdd_info["device"],
                                                                                                                                           medium=hdd_file,
                                                                                                                                           error=e))
                      continue
docs: Reattach linked cloned hard disks.