Fix incorrect azuredisk lun error

pkg/volume/azure_dd/attacher.go

@@ -82,7 +82,7 @@ func (a *azureDiskAttacher) Attach(spec *volume.Spec, nodeName types.NodeName) (
 		klog.V(2).Infof("GetDiskLun returned: %v. Initiating attaching volume %q to node %q.", err, volumeSource.DataDiskURI, nodeName)
 
 		isManagedDisk := (*volumeSource.Kind == v1.AzureManagedDisk)
-		err = diskController.AttachDisk(isManagedDisk, volumeSource.DiskName, volumeSource.DataDiskURI, nodeName, compute.CachingTypes(*volumeSource.CachingMode))
+		lun, err = diskController.AttachDisk(isManagedDisk, volumeSource.DiskName, volumeSource.DataDiskURI, nodeName, compute.CachingTypes(*volumeSource.CachingMode))
 		if err == nil {
 			klog.V(2).Infof("Attach operation successful: volume %q attached to node %q.", volumeSource.DataDiskURI, nodeName)
 		} else {

pkg/volume/azure_dd/azure_dd.go

@@ -44,7 +44,7 @@ type DiskController interface {
 	DeleteManagedDisk(diskURI string) error
 
 	// Attaches the disk to the host machine.
-	AttachDisk(isManagedDisk bool, diskName, diskUri string, nodeName types.NodeName, cachingMode compute.CachingTypes) error
+	AttachDisk(isManagedDisk bool, diskName, diskUri string, nodeName types.NodeName, cachingMode compute.CachingTypes) (int32, error)
 	// Detaches the disk, identified by disk name or uri, from the host machine.
 	DetachDisk(diskName, diskUri string, nodeName types.NodeName) error
 

staging/src/k8s.io/legacy-cloud-providers/azure/azure_controller_common.go

@@ -91,16 +91,17 @@ func (c *controllerCommon) getNodeVMSet(nodeName types.NodeName) (VMSet, error)
 }
 
 // AttachDisk attaches a vhd to vm. The vhd must exist, can be identified by diskName, diskURI.
-func (c *controllerCommon) AttachDisk(isManagedDisk bool, diskName, diskURI string, nodeName types.NodeName, cachingMode compute.CachingTypes) error {
+// return (lun, error)
+func (c *controllerCommon) AttachDisk(isManagedDisk bool, diskName, diskURI string, nodeName types.NodeName, cachingMode compute.CachingTypes) (int32, error) {
 	vmset, err := c.getNodeVMSet(nodeName)
 	if err != nil {
-		return err
+		return -1, err
 	}
 
 	instanceid, err := c.cloud.InstanceID(context.TODO(), nodeName)
 	if err != nil {
 		klog.Warningf("failed to get azure instance id (%v)", err)
-		return fmt.Errorf("failed to get azure instance id for node %q (%v)", nodeName, err)
+		return -1, fmt.Errorf("failed to get azure instance id for node %q (%v)", nodeName, err)
 	}
 
 	diskOpMutex.LockKey(instanceid)
@@ -109,11 +110,11 @@ func (c *controllerCommon) AttachDisk(isManagedDisk bool, diskName, diskURI stri
 	lun, err := c.GetNextDiskLun(nodeName)
 	if err != nil {
 		klog.Warningf("no LUN available for instance %q (%v)", nodeName, err)
-		return fmt.Errorf("all LUNs are used, cannot attach volume (%s, %s) to instance %q (%v)", diskName, diskURI, instanceid, err)
+		return -1, fmt.Errorf("all LUNs are used, cannot attach volume (%s, %s) to instance %q (%v)", diskName, diskURI, instanceid, err)
 	}
 
 	klog.V(2).Infof("Trying to attach volume %q lun %d to node %q.", diskURI, lun, nodeName)
-	return vmset.AttachDisk(isManagedDisk, diskName, diskURI, nodeName, lun, cachingMode)
+	return lun, vmset.AttachDisk(isManagedDisk, diskName, diskURI, nodeName, lun, cachingMode)
 }
 
 // DetachDisk detaches a disk from host. The vhd can be identified by diskName or diskURI.

staging/src/k8s.io/legacy-cloud-providers/azure/azure_controller_common_test.go

@@ -36,7 +36,7 @@ func TestAttachDisk(t *testing.T) {
 
 	diskURI := fmt.Sprintf("/subscriptions/%s/resourceGroups/%s/providers/Microsoft.Compute/disks/disk-name", c.SubscriptionID, c.ResourceGroup)
 
-	err := common.AttachDisk(true, "", diskURI, "node1", compute.CachingTypesReadOnly)
+	_, err := common.AttachDisk(true, "", diskURI, "node1", compute.CachingTypesReadOnly)
 	if err != nil {
 		fmt.Printf("TestAttachDisk return expected error: %v", err)
 	} else {