func (t *Topology) GetVolumeLayout(repType storage.ReplicationType) *VolumeLayout {
replicationTypeIndex := repType.GetReplicationLevelIndex()
if t.replicaType2VolumeLayout[replicationTypeIndex] == nil {
t.replicaType2VolumeLayout[replicationTypeIndex] = NewVolumeLayout(repType, t.volumeSizeLimit, t.pulse)
}
return t.replicaType2VolumeLayout[replicationTypeIndex]
}
func (t *Topology) PickForWrite(repType storage.ReplicationType, count int, dataCenter string) (string, int, *DataNode, error) {
replicationTypeIndex := repType.GetReplicationLevelIndex()
if t.replicaType2VolumeLayout[replicationTypeIndex] == nil {
t.replicaType2VolumeLayout[replicationTypeIndex] = NewVolumeLayout(repType, t.volumeSizeLimit, t.pulse)
}
vid, count, datanodes, err := t.replicaType2VolumeLayout[replicationTypeIndex].PickForWrite(count, dataCenter)
if err != nil || datanodes.Length() == 0 {
return "", 0, nil, errors.New("No writable volumes avalable!")
}
fileId, count := t.sequence.NextFileId(count)
return storage.NewFileId(*vid, fileId, rand.Uint32()).String(), count, datanodes.Head(), nil
}