[libvirt] [PATCH] storage: Support different wiping algorithms

[Daniel P. Berrange]

On Tue, Jan 03, 2012 at 05:12:47PM +0100, Michal Privoznik wrote:
> Currently, we support only filling a volume with zeroes on wiping.
> However, it is not enough as data might still be readable by
> experienced and equipped attacker. Many technical papers have been
> written, therefore we should support other wiping algorithms.
> ---
> Okay, this is not as complete as I'd like it. Wiping could take ages,
> therefore we *want* it to be asynchronous. But that would mean:
> 
> 1) Create new API to answer: "Are we done yet?"

IMHO, we basically want to duplicate the async job system from
virDomainPtr, for virStorageVolPtr.

eg,
      virStorageVolAbortJob(virStorageVolPtr vol);
      virStorageVolGetJobInfo(virStorageVolPtr vol,
                              virStorageVolJobInfoPtr info);

this would be useful for several other storage vol related
APIs. We might also want similar APIs against virStoragePoolPtr

> 2) Create event emitting system - like we have for domains
> 
> 3) Combination of previous two
> 
> In fact, I've started writing events, but it turned out to be
> huge and I am not even in a half yet. I need to find a way of
> re-using event code we already have. But thats another day and
> another patch set.

Yes, the abilty to support async events for other objects like
virStoragePoolPtr, virStorageVolPtr, virNetworkPtr, etc is a
well overdue todo item.


I think it would be acceptable todo option 1 as the first
impl, and then add option 2 as a follow on patchset, since
events are merely an optimization.

Daniel
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