Cinder ThinLVM snapshot deletion fails

[Eric Harney]

Affects stable/grizzly 2013.1.4.

Snapshot deletion for ThinLVMVolumeDriver will fail due to "0a86ef8 Fix secure delete for thick LVM snapshots" being backported but not having the logic which skips wiping for ThinLVM.

This causes the deletion process to fail since we look for the "-cow" device, but this never exists for ThinLVM (only thick).

Not broken in master or stable/havana due to this check which skips wiping for ThinLVM: http://git.openstack.org/cgit/openstack/cinder/tree/cinder/volume/drivers/lvm.py?id=64c6eea4#n202 .

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/grizzly
Review: https://review.openstack.org/54435

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/54444

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/54444
Committed: http://github.com/openstack/cinder/commit/2b49b3670aa2dbc55f777f875dbdb80788ca696e
Submitter: Jenkins
Branch: master

commit 2b49b3670aa2dbc55f777f875dbdb80788ca696e
Author: Eric Harney <email address hidden>
Date: Tue Oct 29 16:39:45 2013 -0400

    Add tests for LVM -cow clearing

    Ensure that volume_clear for Thick LVM snapshot deletion
    references the -cow device, and that it uses the LV instead
    of the -cow device for ThinLVM.

    These tests were written for a change to stable/grizzly --
    but are applicable for general use here as well.

    Related-Bug: #1245529
    Change-Id: I380ad7832d558d9aa73a701cbf3acc35229e70ab

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/54435
Committed: http://github.com/openstack/cinder/commit/64878632a0602879a59e4166232ef389cd6d0a60
Submitter: Jenkins
Branch: stable/grizzly

commit 64878632a0602879a59e4166232ef389cd6d0a60
Author: Eric Harney <email address hidden>
Date: Tue Oct 29 16:39:45 2013 -0400

    Clear correct device when deleting a ThinLVM snap

    The LVM driver tries to wipe a device using dd when
    a snapshot is deleted. For ThinLVM, it is attempting
    to wipe the /dev/mapper/cinder--volumes-<vol>-cow device,
    which does not exist for ThinLVM. This causes snapshot
    deletion to fail for ThinLVM if volume clearing is on.

    When using ThinLVM, only wipe the LV device rather than
    attempting to wipe the -cow device.

    This bug is only present in stable/grizzly (2013.1.4).
    It does not exist in stable/havana or master due to these
    changes:
    f702fe7 Fix secure delete for thick LVM snapshots
    de43923 Don't zero out thin provisioned LV's on delete

    Closes-Bug: #1245529
    Change-Id: I1d8dd618e51cc99b8947fbe0697a1c765c8251ba