add some comment and notes

Author: cvvz

docs/driver-parameters.md

@@ -51,7 +51,7 @@ k8s-azure-created-by: azure
 pvc-92a4d7f2-f23b-4904-bad4-2cbfcff6e388
 ```
 
- - VolumeId is identifier for the volume generated after volume is created by plugin successfully, the format of VolumeId is: `rg#accountName#containerName#uuid#secretNamespace#subsID` 
+ - VolumeId is identifier for the volume generated after volume is created by plugin successfully, the format of VolumeId is: `rg#accountName#containerName#uuid#secretNamespace#subsID`, and if current account is in the same subs as the driver, `subsID` would be empty.
 
 ### Static Provisioning(bring your own storage container)
   > [blobfuse example](../deploy/example/pv-blobfuse-csi.yaml)

pkg/blob/blob.go

@@ -265,7 +265,10 @@ func (d *Driver) Run(endpoint, kubeconfig string, testBool bool) {
 	s.Wait()
 }
 
-// GetContainerInfo get container info according to volume id, e.g.
+// GetContainerInfo get container info according to volume id
+// the format of VolumeId is: rg#accountName#containerName#uuid#secretNamespace#subsID
+//
+// e.g.
 // input: "rg#f5713de20cde511e8ba4900#containerName#uuid#"
 // output: rg, f5713de20cde511e8ba4900, containerName, "" , ""
 // input: "rg#f5713de20cde511e8ba4900#containerName#uuid#namespace#"