Unable to create or delete Snapshots - MetaDataValidationError

Issue

• Unable to create or delete a Snapshot
• The following error is seen on vdsm.log:

ERROR (tasks/6) [storage.Volume] Unexpected error (volume:1070)
Traceback (most recent call last):
  File "/usr/share/vdsm/storage/volume.py", line 1067, in create
    size = volParent.getSize()
  File "/usr/share/vdsm/storage/volume.py", line 1278, in getSize
    return self._manifest.getSize()
  File "/usr/share/vdsm/storage/volume.py", line 176, in getSize
    raise se.MetaDataValidationError()
MetaDataValidationError: Meta Data self-validation failed: ()