* Peter Xu (pet...@redhat.com) wrote: > On Fri, Dec 15, 2017 at 05:16:53PM +0000, Dr. David Alan Gilbert (git) wrote: > > From: "Dr. David Alan Gilbert" <dgilb...@redhat.com> > > > > Hi, > > Where a channel fails asynchronously during connect, call > > back through the migration code so it can clean up. > > In particular this causes the transition of a 'cancelling' state > > to 'cancelled' in the case of: > > > > migrate -d tcp:deadhost:port > > <host tries to connect> > > migrate_cancel > > > > previously the status would get stuck in cancelling because > > the final cleanup didn't happen. > > > > This is the second part of the fix for: > > https://bugzilla.redhat.com/show_bug.cgi?id=1525899 > > IIUC this series tries to deliver the connection error a long way > until migrate_fd_connect() to handle it. But, haven't we already have > a function migrate_fd_error() to do that (which is faster, and > simpler)? > > void migrate_fd_error(MigrationState *s, const Error *error) > { > trace_migrate_fd_error(error_get_pretty(error)); > assert(s->to_dst_file == NULL); > migrate_set_state(&s->state, MIGRATION_STATUS_SETUP, > MIGRATION_STATUS_FAILED); > migrate_set_error(s, error); > notifier_list_notify(&migration_state_notifiers, s); > block_cleanup_parameters(s); > } > > I think it's not handling the case when cancelling. If we let it to > handle the cancelling case well, would it be a simpler fix? > > Moreover, I think this is another good example that migration is not > handling the cleanup "cleanly" in general... I really hope we can do > this better in 2.12. I'll see whether I can give it a shot, but in > all cases it'll be after the merging of existing patches since there > are already quite a lot of dangling patches.
No, I think migrate_fd_error is the cause of the problem here, not the answer. If we stick to the simple rule that a migration must always call migrate_fd_cleanup then the cancellation problems are fixed - I think that's how we make migration 'clean' - a single cleanup routine that always gets called. Dave > Thanks, > > -- > Peter Xu -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
