Re: [Qemu-devel] [PATCH v2 0/6] Mirrored writes using blockdev-transaction

[Luiz Capitulino <lcapitulino@redhat.com>]

On Thu, 01 Mar 2012 17:18:04 +0100
Kevin Wolf <kwolf@redhat.com> wrote:

> Am 01.03.2012 17:02, schrieb Luiz Capitulino:
> > On Thu,  1 Mar 2012 12:21:42 +0100
> > Paolo Bonzini <pbonzini@redhat.com> wrote:
> > 
> >> This implements all ingredients to establish mirrored writes.
> > 
> > This looks good to me. I just have two comments:
> > 
> >  1. I'm wondering if it would make more sense to have this transaction
> >     operation in qmp instead of the block layer. Looks more complex to do though,
> >     so I'm ok with this implementation
> 
> Depends on what you're thinking of. Renaming the command to just
> 'transaction' and allowing anything to be added to the union wouldn't be
> very complex.
> 
> The one thing we would need to change in order to make it generally
> useful is to move the actual logic into prepare/commit/abort handlers. I
> discussed this with Paolo on IRC and I think the conclusion was that for
> now the approach in the patches is good enough, but in the long run
> we'll switch. It doesn't affect external interfaces, so we can do it
> whenever we like.

Yes, that's what I called "transaction operation in qmp", but I don't mind
accepting this one and deferring the more complex idea to the future.