def BlockdevAddchildren(parent_cdev, new_cdevs):
  parent_bdev = _RecursiveFindBD(parent_cdev)
  if parent_bdev is None:
    _Fail("Can't find parent device '%s' in add children", parent_cdev)
  new_bdevs = [_RecursiveFindBD(disk) for disk in new_cdevs]
  if new_bdevs.count(None) > 0:
    _Fail("Can't find new device(s) to add: %s:%s", new_bdevs, new_cdevs)
  parent_bdev.AddChildren(new_bdevs)
Extend a mirrored block device.
dataset/ETHPy150Open ganeti/ganeti/lib/backend.py/BlockdevAddchildren