On Fri, Oct 21, 2016 at 11:06:21AM +0200, Markus Armbruster wrote: > "Dr. David Alan Gilbert" <dgilb...@redhat.com> writes: > > > * Markus Armbruster (arm...@redhat.com) wrote: > >> "Daniel P. Berrange" <berra...@redhat.com> 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. 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/ :|
