RBD Plugin: No need to acquire advisory lock any more!

With central attachdetach controller, we don't need to lock the image
any more. But for backward compatibility, we should:

1) Check if the image is still used by nodes running old kubelet in
attaching.
2) Clean old rbd.json file and remove lock if found in detaching.

pkg/volume/rbd/rbd_test.go

@@ -18,16 +18,13 @@ package rbd
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
-	"path/filepath"
 	"reflect"
 	"strings"
 	"sync"
 	"testing"
 	"time"
 
-	"github.com/stretchr/testify/assert"
 	"k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/types"
@@ -397,87 +394,6 @@ func TestPersistentClaimReadOnlyFlag(t *testing.T) {
 	}
 }
 
-func TestPersistAndLoadRBD(t *testing.T) {
-	tmpDir, err := utiltesting.MkTmpdir("rbd_test")
-	if err != nil {
-		t.Fatalf("error creating temp dir: %v", err)
-	}
-	defer os.RemoveAll(tmpDir)
-
-	testcases := []struct {
-		rbdMounter               rbdMounter
-		expectedJSONStr          string
-		expectedLoadedRBDMounter rbdMounter
-	}{
-		{
-			rbdMounter{},
-			`{"Mon":null,"Id":"","Keyring":"","Secret":""}`,
-			rbdMounter{},
-		},
-		{
-			rbdMounter{
-				rbd: &rbd{
-					podUID:          "poduid",
-					Pool:            "kube",
-					Image:           "some-test-image",
-					ReadOnly:        false,
-					MetricsProvider: volume.NewMetricsStatFS("/tmp"),
-				},
-				Mon:     []string{"127.0.0.1"},
-				Id:      "kube",
-				Keyring: "",
-				Secret:  "QVFEcTdKdFp4SmhtTFJBQUNwNDI3UnhGRzBvQ1Y0SUJwLy9pRUE9PQ==",
-			},
-			`
-{
-	"Pool": "kube",
-	"Image": "some-test-image",
-	"ReadOnly": false,
-	"Mon": ["127.0.0.1"],
-	"Id": "kube",
-	"Keyring": "",
-	"Secret": "QVFEcTdKdFp4SmhtTFJBQUNwNDI3UnhGRzBvQ1Y0SUJwLy9pRUE9PQ=="
-}
-			`,
-			rbdMounter{
-				rbd: &rbd{
-					Pool:     "kube",
-					Image:    "some-test-image",
-					ReadOnly: false,
-				},
-				Mon:     []string{"127.0.0.1"},
-				Id:      "kube",
-				Keyring: "",
-				Secret:  "QVFEcTdKdFp4SmhtTFJBQUNwNDI3UnhGRzBvQ1Y0SUJwLy9pRUE9PQ==",
-			},
-		},
-	}
-
-	util := &RBDUtil{}
-	for _, c := range testcases {
-		err = util.persistRBD(c.rbdMounter, tmpDir)
-		if err != nil {
-			t.Errorf("failed to persist rbd: %v, err: %v", c.rbdMounter, err)
-		}
-		jsonFile := filepath.Join(tmpDir, "rbd.json")
-		jsonData, err := ioutil.ReadFile(jsonFile)
-		if err != nil {
-			t.Errorf("failed to read json file %s: %v", jsonFile, err)
-		}
-		if !assert.JSONEq(t, c.expectedJSONStr, string(jsonData)) {
-			t.Errorf("json file does not match expected one: %s, should be %s", string(jsonData), c.expectedJSONStr)
-		}
-		tmpRBDMounter := rbdMounter{}
-		err = util.loadRBD(&tmpRBDMounter, tmpDir)
-		if err != nil {
-			t.Errorf("faild to load rbd: %v", err)
-		}
-		if !reflect.DeepEqual(tmpRBDMounter, c.expectedLoadedRBDMounter) {
-			t.Errorf("loaded rbd does not equal to expected one: %v, should be %v", tmpRBDMounter, c.rbdMounter)
-		}
-	}
-}
-
 func TestGetSecretNameAndNamespace(t *testing.T) {
 	secretName := "test-secret-name"
 	secretNamespace := "test-secret-namespace"