Detect device path for mount point

pkg/driver/node.go

@@ -235,12 +235,21 @@ func (d *nodeService) NodeExpandVolume(ctx context.Context, req *csi.NodeExpandV
 		// TODO: range specified
 	}
 
-	r := resizefs.NewResizeFs(d.mounter)
-
-	// TODO: get the mount path that's required for XFS
-	_, err := r.Resize(req.GetVolumePath(), "" /* mount path for xfs */)
+	args := []string{"-o", "source", "--noheadings", "--target", req.GetVolumePath()}
+	output, err := d.mounter.Exec.Run("findmnt", args...)
 	if err != nil {
-		return nil, err
+		return nil, status.Errorf(codes.Internal, "Could not determine device path: %v", err)
+
+	}
+
+	devicePath := strings.TrimSpace(string(output))
+	if len(devicePath) == 0 {
+		return nil, status.Errorf(codes.Internal, "Could not get valid device for mount path: %q", req.GetVolumePath())
+	}
+
+	r := resizefs.NewResizeFs(d.mounter)
+	if _, err := r.Resize(devicePath, req.GetVolumePath()); err != nil {
+		return nil, status.Errorf(codes.Internal, "Could not resize volume %q:  %v", volumeID, err)
 	}
 
 	return &csi.NodeExpandVolumeResponse{}, nil