From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53931) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bxYQm-0003oW-7F for qemu-devel@nongnu.org; Fri, 21 Oct 2016 07:56:13 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bxYQi-0000ig-FU for qemu-devel@nongnu.org; Fri, 21 Oct 2016 07:56:12 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33078) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1bxYQi-0000hR-BA for qemu-devel@nongnu.org; Fri, 21 Oct 2016 07:56:08 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 160849F738 for ; Fri, 21 Oct 2016 11:56:07 +0000 (UTC) Date: Fri, 21 Oct 2016 12:56:03 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20161021115603.GF2039@work-vm> References: <20161019180616.GF2035@work-vm> <87oa2fwg9z.fsf@dusky.pond.sub.org> <20161020090356.GD12145@redhat.com> <20161020095835.GC2039@work-vm> <87funrti86.fsf@dusky.pond.sub.org> <20161020110832.GG12145@redhat.com> <87insnqllc.fsf@dusky.pond.sub.org> <20161020175648.GN2039@work-vm> <8760omm5pu.fsf@dusky.pond.sub.org> <20161021093756.GC6585@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161021093756.GC6585@redhat.com> Subject: Re: [Qemu-devel] chardev's and fd's in monitors List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Daniel P. Berrange" Cc: Markus Armbruster , qemu-devel@nongnu.org * Daniel P. Berrange (berrange@redhat.com) wrote: > On Fri, Oct 21, 2016 at 11:06:21AM +0200, Markus Armbruster wrote: > > "Dr. David Alan Gilbert" writes: > > > > > * Markus Armbruster (armbru@redhat.com) wrote: > > >> "Daniel P. Berrange" writes: > > [...] > > >> > Realistically all the major backend subsystems (chardev, network, block, > > >> > ui and migration) need to be converted to Error ** propagation, since > > >> > they all ultimately call into some common code that reports Error **. > > >> > > >> Infrastucture generally doesn't know how it's used, which means > > >> error_report() is generally wrong there. Sufficiently simple functions > > >> can keep returning -errno, null, whatever, but the interesting stuff > > >> needs to use Error. > > >> > Very few places will end up being able to stick with -errno, or plain > > >> > error_report in the long term. > > >> > > >> Not sure about "very few". Less than now. We'll see. > > > > > > I'd also prefer we got the very-few level; Migration used to be > > > characterised by getting a 'load of migration failed -22' and having > > > no clue in the logs to why; I've slowly fought back to be able > > > to get an error from the lowest level that caused the failure. > > > I want more of that, so that when someone gets a rare failure in the field > > > I can see why. > > > > When it's about details that are only useful for debugging, logging > > might be a practical alternative. No excuse for shoddy error reporting, > > of course. > > FWIW, I would very much like it if incoming migration were able to report > the error failing to load migration stream back via the monitor, instead > of spitting them to stderr - the latter makes it hard for libvirt to > provide good error report to the users. As long as we also get them in the stderr log then that's fine. Dave > On the outgoing side we've now fed the errors back via the query-migrate > command - the same approach could be used on the incoming side. > > > Regards, > Daniel > -- > |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| > |: http://libvirt.org -o- http://virt-manager.org :| > |: http://entangle-photo.org -o- http://search.cpan.org/~danberr/ :| -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK