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graph driver-device mapper-04libdevmapper基本操作
// 創建thin pool
// 調用路徑：NewDeviceSet->initDevmapper->createPool
1.1 func createPool(poolName string, dataFile, metadataFile *os.File, poolBlockSize uint32) error {
//通過task封裝與libdevmapper的交互
task, err := createTask(DeviceCreate, poolName)
if task == nil {
return err
}
//data block device的大小，通過ioctl
size, err := GetBlockDeviceSize(dataFile)
if err != nil {
return fmt.Errorf("Can't get data size %s", err)
}
//創建thin pool的參數
params := fmt.Sprintf("%s %s %d 32768 1 skip_block_zeroing", metadataFile.Name(), dataFile.Name(), poolBlockSize)
//添加函數參數
if err := task.AddTarget(0, size/512, "thin-pool", params); err != nil {
return fmt.Errorf("Can't add target %s", err)
}
//創建一個同步量
var cookie uint = 0
if err := task.SetCookie(&cookie, 0); err != nil {
return fmt.Errorf("Can't set cookie %s", err)
}
//執行任務
if err := task.Run(); err != nil {
return fmt.Errorf("Error running DeviceCreate (createPool) %s", err)
}
//等待thin pool創建完成
UdevWait(cookie)
return nil
}
// 創建操作，task封裝對devicemapper的操作
1.2 func createTask(t TaskType, name string) (*Task, error) {
//創建tasktype對應的封裝函數
task := TaskCreate(t)
if task == nil {
return nil, fmt.Errorf("Can't create task of type %d", int(t))
}
if err := task.SetName(name); err != nil {
return nil, fmt.Errorf("Can't set task name %s", name)
}
return task, nil
}
// 創建一個指定的操作類型
1.3 func TaskCreate(tasktype TaskType) *Task {
//創建操作
Ctask := DmTaskCreate(int(tasktype))
if Ctask == nil {
return nil
}
task := &Task{unmanaged: Ctask}
runtime.SetFinalizer(task, (*Task).destroy)
return task
}
// 創建指定的操作
// DmTaskCreate=dmTaskCreateFct
1.4 func dmTaskCreateFct(taskType int) *CDmTask {
return (*CDmTask)(C.dm_task_create(C.int(taskType)))
}
最後更新：2017-04-03 05:39:32