Description of problem:

When coping a template that was create as raw sparse on NFS to ISCSI domain,it is actually creating a raw preallocated template (BZ #1098258),therefore,the operation of creating vm with thin provision disk from template is aloud by ovirt-engine in the case of an iscsi domain which has free space that is less than disks actual size, but it fails (with termination of "VDSErrorException") sense there is not enough space for the completion of the command


Version-Release number of selected component (if applicable):
vdsm-4.14.7-2.el6ev.x86_64
rhevm-3.4.0-0.20.el6ev.noarch

How reproducible:
100%

Steps to Reproduce:

Setup:have a dc with 2 domains of each kind(1 NFS,1ISCSI)

1.create vm+thin provision disk on NFS,make a template out of this vm
2.copy template to ISCSI domain and make sure-> 
{disks actual size} > {ISCSI's free space} > {3giga}
3.create vm from template (mark it thin provision on ISCSI domain)

Actual results:
operation fails from vdsm logs:

ERROR::2014-05-18 12:58:16,790::image::736::Storage.Image::(copyCollapsed) Unexpected error
Traceback (most recent call last):
  File "/usr/share/vdsm/storage/image.py", line 731, in copyCollapsed
    dstVol.extend(newsize)
  File "/usr/share/vdsm/storage/blockVolume.py", line 272, in extend
    lvm.extendLV(self.sdUUID, self.volUUID, sizemb)
  File "/usr/share/vdsm/storage/lvm.py", line 1151, in extendLV
    _resizeLV("lvextend", vgName, lvName, size)
  File "/usr/share/vdsm/storage/lvm.py", line 1145, in _resizeLV
    free_size / constants.MEGAB))

from ovirt-engine logs:

2014-05-18 12:58:25,128 ERROR [org.ovirt.engine.core.bll.SPMAsyncTask] (DefaultQuartzScheduler_Worker-80) BaseAsyncTask::LogEndTaskFailure: Task a63ba93d-505a-4cfe-b860-4a3bb45d50c7 (Parent Command AddVmFromTemplate, Parameters Type org.ovirt.engine.core.common asynctasks.AsyncTaskParameters) ended with failure:
 - Result: cleanSuccess
-- Message: VDSGenericException: VDSErrorException: Failed in vdscommand to HSMGetAllTa ksStatusesVDS, error = Volume Group not big enough,
-- Exception: VDSGenericException: VDSErrorException: Failed in vdscommand to HSMGetAllTasksStatusesVDS, error = Volume Group not big enough 


Expected results:
operation should succeed

Additional info: