LVM volume copy/clear assumes volume_dd_blocksize is set to 1M

[Eric Harney]

The recent change to enable adjusting volume dd blocksize to sizes other than 1M does not adjust the "count" parameter of the dd command. Therefore, if you change volume_dd_blocksize to (for example) "1K", for a 1GB volume, only the first 1 MB of the volume will be copied/wiped.

The "count" parameter for dd needs to scale based on what the volume_dd_blocksize option is set to to ensure the whole volume is copied/wiped.

https://review.openstack.org/#/c/24833/1/cinder/volume/drivers/lvm.py

(Note: not tested, just observed while reading code. Feel free to correct if I'm missing something.)

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/33523

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/33523
Committed: http://github.com/openstack/cinder/commit/411a85d0958a574ff6e3b27569b7ce248675c731
Submitter: Jenkins
Branch: master

commit 411a85d0958a574ff6e3b27569b7ce248675c731
Author: Zhiteng Huang <email address hidden>
Date: Wed Jun 19 04:43:26 2013 +0800

    Calculate count for customized dd blocksize

    In previous commit we introduce a configurable blocksize option for
    'dd' command, however the 'count' value wasn't updated accordingly.
    As a result, count could be too small which is bug. This patch
    introduce a private method to 1) validate custom dd blocksize; 2)
    calculate correct count value.

    Fix bug: 1192258

    Change-Id: Icfd2d80e8f615ed585bd1d40c741a97cf55299d3