code: func (s *VolumeStore) CountReferences(v volume.Volume) int {
  	name := normalizeVolumeName(v.Name())
  
  	s.locks.Lock(name)
  	defer s.locks.Unlock(name)
  	s.globalLock.Lock()
  	defer s.globalLock.Unlock()
  
  	return len(s.refs[name])
  }
docs: // CountReferences gives a count of all references for a given volume.