How to make a VG/LV readonly?

Issue

• For some reason, the particular VG/LV need to be put into readonly mode.
• When follow the steps below to make a VG/LV readonly , it fails with error below:

# vgchange -an vg1
  0 logical volume(s) in volume group "vg1" now active

# lvs
  LV     VG     Attr       LSize   Pool   Origin Data%  Meta%  Move Log Cpy%Sync Convert
  lv1     vg1  -wi-------   1.00g                                                      

# vgchange -ay --readonly vg1
  Operation prohibited while --readonly is set.
  Can't get lock for  vg1.
  Cannot process volume group vg1

Or:

# lvchange -ay --readonly /dev/vg1/lv1
  Operation prohibited while --readonly is set.
  Can't get lock for vg1.
  Cannot process volume group vg1