Re: [Qemu-devel] [PATCH RFC v6 5/7] migration: fix the multifd code when receiving less channels

[Peter Xu]

On Tue, Oct 30, 2018 at 06:05:18PM +0800, Fei Li wrote:

[...]

> > > @@ -1366,6 +1373,10 @@ bool multifd_recv_new_channel(QIOChannel *ioc)
> > >                          QEMU_THREAD_JOINABLE);
> > >       atomic_inc(&multifd_recv_state->count);
> > >       return multifd_recv_state->count == migrate_multifd_channels();
> > > +fail:
> > > +    qemu_fclose(mis->from_src_file);
> > > +    mis->from_src_file = NULL;
> > > +    return false;
> > Do we need this?
> > 
> > I'd suggest to put all cleanups into a single function.  For dest vm
> > I say it's process_incoming_migration_bh.
> > 
> > Regards,
> > 
> Not sure whether I understand correctly, if multifd_recv_new_channel()
> fails,
> that means migration_incoming_process() will not be called, then
> process_incoming_migration_co() and process_incoming_migration_bh()
> will not be called either. In that way, there is no cleanup.

Sorry the funtion name I wanted to paste is something like
migration_incoming_state_destroy()...  Anyway I still don't feel that
right to close the mis->from_src_file in a multifd special path.

For now, I'll either ignore the cleanup part (AFAIU the TLS failure
will also ignore it when migration_tls_channel_process_incoming fails)
and just print the extra error message, or you can also look into how
to cleanup the dest vm in a better way.  That could be someting like
calling migration_incoming_state_destroy() somewhere in
migration_channel_process_incoming() when failure happens but I'm not
sure.

Regards,

-- 
Peter Xu