From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:51399)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <lcapitulino@redhat.com>) id 1Uu2L0-0005oP-E2
	for qemu-devel@nongnu.org; Tue, 02 Jul 2013 11:17:56 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <lcapitulino@redhat.com>) id 1Uu2Ku-0001ue-2V
	for qemu-devel@nongnu.org; Tue, 02 Jul 2013 11:17:50 -0400
Received: from mx1.redhat.com ([209.132.183.28]:45970)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <lcapitulino@redhat.com>) id 1Uu2Kt-0001uT-P3
	for qemu-devel@nongnu.org; Tue, 02 Jul 2013 11:17:43 -0400
Date: Tue, 2 Jul 2013 11:16:59 -0400
From: Luiz Capitulino <lcapitulino@redhat.com>
Message-ID: <20130702111659.507c705c@redhat.com>
In-Reply-To: <51D2E767.9010106@redhat.com>
References: <CDF71D4D.35C1%Tomoki.Sekiyama@hds.com>
	<51D274DB.1080009@redhat.com> <20130702100903.43435654@redhat.com>
	<51D2E767.9010106@redhat.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Subject: Re: [Qemu-devel] [PATCH v4 08/10] qemu-ga: call Windows VSS
 requester in fsfreeze command handler
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Laszlo Ersek <lersek@redhat.com>
Cc: "libaiqing@huawei.com" <libaiqing@huawei.com>, "stefanha@gmail.com" <stefanha@gmail.com>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, "mdroth@linux.vnet.ibm.com" <mdroth@linux.vnet.ibm.com>, "vrozenfe@redhat.com" <vrozenfe@redhat.com>, Tomoki Sekiyama <tomoki.sekiyama@hds.com>, "pbonzini@redhat.com" <pbonzini@redhat.com>, Seiji Aguchi <seiji.aguchi@hds.com>, "areis@redhat.com" <areis@redhat.com>

On Tue, 02 Jul 2013 16:44:55 +0200
Laszlo Ersek <lersek@redhat.com> wrote:

> On 07/02/13 16:09, Luiz Capitulino wrote:
> > On Tue, 02 Jul 2013 08:36:11 +0200
> > Laszlo Ersek <lersek@redhat.com> wrote:
> > 
> >> On 07/01/13 19:59, Tomoki Sekiyama wrote:
> >>> On 7/1/13 9:29 , "Laszlo Ersek" <lersek@redhat.com> 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?