Re: [Qemu-devel] [PATCH v4 08/10] qemu-ga: call Windows VSS requester in fsfreeze command handler

[Luiz Capitulino]

On Tue, 02 Jul 2013 16:44:55 +0200
Laszlo Ersek <address@hidden> wrote:

> On 07/02/13 16:09, Luiz Capitulino wrote:
> > On Tue, 02 Jul 2013 08:36:11 +0200
> > Laszlo Ersek <address@hidden> wrote:
> > 
> >> On 07/01/13 19:59, Tomoki Sekiyama wrote:
> >>> On 7/1/13 9:29 , "Laszlo Ersek" <address@hidden> wrote:
> >>>
> >>>>> +error:
> >>>>> +    qmp_guest_fsfreeze_thaw(NULL);
> >>>>
> >>>> Passing NULL here as "errp" concerns me slightly. I've been assuming
> >>>> that "errp" is never NULL due to the outermost QMP layer always wanting
> >>>> to receive errors and to serialize them.
> >>>>
> >>>> Specifically, a NULL "errp" would turn all error_set*(errp, ...) calls
> >>>> into no-ops under qmp_guest_fsfreeze_thaw(), and all error_is_set(errp)
> >>>> questions would answer with false. That said, nothing seems to be
> >>>> affected right now.
> >>>>
> >>>> Maybe a dummy local variable would be more future-proof... OTOH it would
> >>>> be stylistically questionable :)
> >>>
> >>> OK, then it should be:
> >>>     Error *local_err = NULL;
> >>> ...
> >>> error:
> >>>     qmp_guest_fsfreeze_thaw(&local_err);
> >>>     if (error_is_set(&local_err)) {
> >>>         error_free(local_err);
> >>>     }
> >>
> >> I think so, yes.
> >>
> >> You could also log it before freeing it I guess:
> >>
> >>     g_debug("cleanup thaw: %s", error_get_pretty(local_err));
> >>
> >> or some such, but it's probably not important.
> > 
> > I'd rather do something like that, otherwise it doesn't seem to
> > make sense to pass Error as qmp_guest_fsfreeze_thaw() does
> > use a local Error.
> 
> No, the win32 version of qmp_guest_fsfreeze_thaw() being added by this
> patch doesn't.

Oh, I looked into the POSIX one. But then, it's qmp_guest_fsfreeze_thaw()
that has to be fixed, isn't it?