Re: [Qemu-devel] [PATCH v7 22/23] migration/qmp: add command migrate-pause

[Peter Xu <peterx@redhat.com>]

On Mon, Mar 12, 2018 at 05:36:09PM +0000, Dr. David Alan Gilbert wrote:
> * Peter Xu (peterx@redhat.com) wrote:
> > It pauses an ongoing migration.  Currently it only supports postcopy.
> > Note that this command will work on either side of the migration.
> > Basically when we trigger this on one side, it'll interrupt the other
> > side as well since the other side will get notified on the disconnect
> > event.
> > 
> > However, it's still possible that the other side is not notified, for
> > example, when the network is totally broken, or due to some firewall
> > configuration changes.  In that case, we will also need to run the same
> > command on the other side so both sides will go into the paused state.
> > 
> > Signed-off-by: Peter Xu <peterx@redhat.com>
> > ---
> >  migration/migration.c | 27 +++++++++++++++++++++++++++
> >  qapi/migration.json   | 16 ++++++++++++++++
> >  2 files changed, 43 insertions(+)
> > 
> > diff --git a/migration/migration.c b/migration/migration.c
> > index 180552329c..f31fcbb0d5 100644
> > --- a/migration/migration.c
> > +++ b/migration/migration.c
> > @@ -1448,6 +1448,33 @@ void qmp_migrate_recover(const char *uri, Error **errp)
> >      qemu_start_incoming_migration(uri, errp);
> >  }
> >  
> > +void qmp_migrate_pause(Error **errp)
> > +{
> > +    MigrationState *ms = migrate_get_current();
> > +    MigrationIncomingState *mis = migration_incoming_get_current();
> > +    int ret;
> > +
> > +    if (ms->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) {
> > +        /* Source side, during postcopy */
> > +        ret = qemu_file_shutdown(ms->to_dst_file);
> 
> How did this fix the race I mentioned last time?

Ah sorry I missed that one.  I'll reply there.

-- 
Peter Xu