csi/controller: make the volme expand really work

    - Execute lvextend multiple times will get EIO if
      size not change. We need to add pre-check for
      avoiding that.

Signed-off-by: Vicente Cheng <vicente.cheng@suse.com>

pkg/lvm/lvm.go

@@ -554,18 +554,36 @@ func extendLVS(name string, size uint64, isBlock bool) (string, error) {
 		return "", fmt.Errorf("logical volume %s does not exist", name)
 	}
 
-	// TODO: check available capacity, fail if request doesn't fit
-
 	executor := cmd.NewExecutor()
-	args := []string{"-L", fmt.Sprintf("%db", size)}
+	targetLVName := fmt.Sprintf("%s/%s", vgName, name)
+	// check current lv size
+	args := []string{"--noheadings", "--unit", "b", "-o", "Size"}
+	args = append(args, targetLVName)
+	out, err := executor.Execute("lvs", args)
+	if err != nil {
+		return "", fmt.Errorf("unable to get size of lv %s: %w", name, err)
+	}
+	lvSizeStr := strings.TrimSpace(out)
+	lvSizeStr = strings.TrimSuffix(lvSizeStr, "B")
+	klog.Infof("current size of lv %s is %s", name, lvSizeStr)
+	lvSize, err := strconv.ParseUint(lvSizeStr, 10, 64)
+	if err != nil {
+		return "", fmt.Errorf("unable to parse size of lv %s: %w", name, err)
+	}
+	if lvSize == size {
+		klog.Infof("logical volume %s already has the requested size %d", name, size)
+		return "", nil
+	}
+
+	args = []string{"-L", fmt.Sprintf("%db", size)}
 	if isBlock {
 		args = append(args, "-n")
 	} else {
 		args = append(args, "-r")
 	}
 	args = append(args, fmt.Sprintf("%s/%s", vgName, name))
 	klog.Infof("lvextend %s", args)
-	out, err := executor.Execute("lvextend", args)
+	out, err = executor.Execute("lvextend", args)
 	return out, err
 }
 

pkg/lvm/nodeserver.go

@@ -230,6 +230,7 @@ func (ns *nodeServer) NodeGetVolumeStats(ctx context.Context, in *csi.NodeGetVol
 
 func (ns *nodeServer) NodeExpandVolume(ctx context.Context, req *csi.NodeExpandVolumeRequest) (*csi.NodeExpandVolumeResponse, error) {
 
+	klog.Infof("NodeExpandVolume: %s", req)
 	// Check arguments
 	if req.GetCapacityRange() == nil {
 		return nil, status.Error(codes.InvalidArgument, "Volume capability missing in request")