[libvirt] [PATCH 1/2] storage: Don't delete Ploop volumes twice

[Martin Kletzander]

On Fri, Jul 15, 2016 at 02:51:21PM +0300, Olga Krishtal wrote:
>On 15/07/16 11:37, Martin Kletzander wrote:
>> On Fri, Jul 15, 2016 at 09:41:11AM +0200, Ján Tomko wrote:
>>> On Thu, Jul 14, 2016 at 02:27:40PM +0200, Martin Kletzander wrote:
>>>> When reinitializing Ploop volumes we also went through the rutine of
>>>> the
>>>> normal wipe, effectively removing the root.hds file twice.
>>>
>>> The file was wiped with the selected algorithm first (without deletion),
>>> then reinitialized to make sure you can delete it via libvirt later.
>>>
>>
>> You're right, I missed that what I was describing only happened with
>> VIR_STORAGE_VOL_WIPE_ALG_ZERO.  Anyway since the description for
>> vol-wipe is:
>>
>>  "Ensure data previously on a volume is not accessible to future reads"
>>
>> wiping algorithm does not really make sense for file-based storage.
>> That's kind of the whole point of this series.
>Actually, virStorageBackendVolWipePloop only deletes root.hds and
>DiscDescriptor.xml.
>So the data on block device can still be accessible.
>To prevent this we used little path/to/volume manipulation and wiped
>root.hds firstly and
>only then called virStorageBackendVolWipePloop. It is incorrect to call
>only this function
>for ploop.
>>
>>> We could get rid of the reinitialization if we make sure libvirt can
>>> operate on the volume (after wiping, pretty much only delete makes
>>> sense), but removing the actual wiping is wrong.
>>>

Oh, I totally misunderstood how the volume is stored then.  Thanks for
the info, I'll try to repost this in order for it not to just fix this
but to suit, hopefully, most people as well.

Have a nice day,
Martin
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: Digital signature
URL: <http://listman.redhat.com/archives/libvir-list/attachments/20160715/6bb2b966/attachment-0001.sig>