Re: [Qemu-block] [Qemu-devel] [PATCH] migration: re-active images when migration fails to complete

[Kevin Wolf]

Forwarding to qemu-block so I won't forget to have a look.

Am 19.11.2016 um 12:43 hat zhanghailiang geschrieben:
> commit fe904ea8242cbae2d7e69c052c754b8f5f1ba1d6 fixed a case
> which migration aborted QEMU because it didn't regain the control
> of images while some errors happened.
> 
> Actually, we have another case in that error path to abort QEMU
> because of the same reason:
>     migration_thread()
>         migration_completion()
>            bdrv_inactivate_all() ----------------> inactivate images
>            qemu_savevm_state_complete_precopy()
>                socket_writev_buffer() --------> error because destination 
> fails
>              qemu_fflush() -------------------> set error on migration stream
>            qemu_mutex_unlock_iothread() ------> unlock
>     qmp_migrate_cancel() ---------------------> user cancelled migration
>         migrate_set_state() ------------------> set migrate CANCELLING
>     migration_completion() -----------------> go on to fail_invalidate
>         if (s->state == MIGRATION_STATUS_ACTIVE) -> Jump this branch
>     migration_thread() -----------------------> break migration loop
>       vm_start() -----------------------------> restart guest with inactive
>                                                 images
> We failed to regain the control of images because we only regain it
> while the migration state is "active", but here users cancelled the migration
> when they found some errors happened (for example, libvirtd daemon is shutdown
> in destination unexpectedly).
> 
> Signed-off-by: zhanghailiang <address@hidden>
> ---
>  migration/migration.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/migration/migration.c b/migration/migration.c
> index f498ab8..0c1ee6d 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -1752,7 +1752,8 @@ fail_invalidate:
>      /* If not doing postcopy, vm_start() will be called: let's regain
>       * control on images.
>       */
> -    if (s->state == MIGRATION_STATUS_ACTIVE) {
> +    if (s->state == MIGRATION_STATUS_ACTIVE ||
> +        s->state == MIGRATION_STATUS_CANCELLING) {
>          Error *local_err = NULL;
>  
>          bdrv_invalidate_cache_all(&local_err);
> -- 
> 1.8.3.1
> 
> 
>