Description of problem:

In some  cases, the pivot is not initiated by the vdsm even when the block commit is 100%. 

virsh -r blockjob --info <vm-name> vdc shows  "Active Block Commit: [100 %]" . 

In the  "vdsClient -s 0 getVmStats" , it's showing wrong "cur" value even when the libvirt show block commit as 100%.

vmJobs = {'be3d91ee-a906-4ef3-b5f8-955f5c04dc08': {'end': '143720448', 'cur': '31588352', 'imgUUID': '9c3205b6-13ba-4580-b9ec-8b1a8fa15a67', 'blockJobType': 'commit', 'bandwidth': 0, 'id': 'be3d91ee-a906-4ef3-b5f8-955f5c04dc08', 'jobType': 'block'}

IIUC, vdsm uses blockJobInfo to get the current progress of block commit. 

===
liveInfo = self._dom.blockJobInfo(drive.name, 0)
----                
----
doPivot = self._activeLayerCommitReady(liveInfo)
-----
def _activeLayerCommitReady(self, jobInfo):
-----
  if (jobInfo['cur'] == jobInfo['end'] and jobInfo['type'] == pivot):
    return True
  return False
===

I think somehow the vdsm lose the track of block commit job and is reporting  incorrect values and hence pivot is never initiated.  

Version-Release number of selected component (if applicable):

vdsm-4.17.33-1.el7ev.noarch
rhevm-3.6.9.2-0.1.el6.noarch

How reproducible:

Unknown

Steps to Reproduce:

Issue was observed in customer environment when deleting a snapshot from RHEV-M which contains 4 disks.

Actual results:

Pivot is never initiated by the vdsm even when the block copy is 100%

Expected results:

Deleting snapshot should work

Additional info: