Re: [Qemu-devel] [PATCH] Migration: Generate the completed event only when we complete

[Juan Quintela <quintela@redhat.com>]

Amit Shah <amit.shah@redhat.com> wrote:
> On (Tue) 13 Oct 2015 [12:21:27], Dr. David Alan Gilbert (git) wrote:
>> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
>> 
>> The current migration-completed event is generated a bit too early,
>> which means that an eager libvirt that's ready to go as soon
>> as it sees the event ends up racing with the actual end of migration.
>> 
>> This corresponds to RH bug:
>> https://bugzilla.redhat.com/show_bug.cgi?id=1271145
>> 
>> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
>
> Reviewed-by: Amit Shah <amit.shah@redhat.com>
>
>>  migration/migration.c | 8 +++++++-
>>  1 file changed, 7 insertions(+), 1 deletion(-)
>> 
>> diff --git a/migration/migration.c b/migration/migration.c
>> index b7de9b7..3d40f24 100644
>> --- a/migration/migration.c
>> +++ b/migration/migration.c
>> @@ -294,12 +294,12 @@ static void process_incoming_migration_co(void *opaque)
>>          migrate_decompress_threads_join();
>>          exit(EXIT_FAILURE);
>>      }
>> -    migrate_generate_event(MIGRATION_STATUS_COMPLETED);
>>      qemu_announce_self();
>
> Related in this context (but independent of this patch): this
> announce_self should happen after we're through with all the error
> cases: we don't want to announce our new IP and end up having run on
> src due to a failed migration.


Yeap, sounds very reasonable.

>
>>      /* Make sure all file formats flush their mutable metadata */
>>      bdrv_invalidate_cache_all(&local_err);
>>      if (local_err) {
>> +        migrate_generate_event(MIGRATION_STATUS_FAILED);
>>          error_report_err(local_err);
>>          migrate_decompress_threads_join();
>>          exit(EXIT_FAILURE);
>
> 		Amit