Re: [Qemu-devel] [PATCH] migration: Don't activate block devices if using -S

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Dr. David Alan Gilbert (git) (dgilbert@redhat.com) wrote:
> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> 
> Activating the block devices causes the locks to be taken on
> the backing file.  If we're running with -S and the destination libvirt
> hasn't started the destination with 'cont', it's expecting the locks are
> still untaken.
> 
> Don't activate the block devices if we're not going to autostart the VM;
> 'cont' already will do that anyway.
> 
> bz: https://bugzilla.redhat.com/show_bug.cgi?id=1560854
> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Queued

> ---
>  migration/migration.c | 22 +++++++++++++++-------
>  1 file changed, 15 insertions(+), 7 deletions(-)
> 
> diff --git a/migration/migration.c b/migration/migration.c
> index 52a5092add..58bd382730 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -306,13 +306,21 @@ static void process_incoming_migration_bh(void *opaque)
>      Error *local_err = NULL;
>      MigrationIncomingState *mis = opaque;
>  
> -    /* Make sure all file formats flush their mutable metadata.
> -     * If we get an error here, just don't restart the VM yet. */
> -    bdrv_invalidate_cache_all(&local_err);
> -    if (local_err) {
> -        error_report_err(local_err);
> -        local_err = NULL;
> -        autostart = false;
> +    /* Only fire up the block code now if we're going to restart the
> +     * VM, else 'cont' will do it.
> +     * This causes file locking to happen; so we don't want it to happen
> +     * unless we really are starting the VM.
> +     */
> +    if (autostart && (!global_state_received() ||
> +        global_state_get_runstate() == RUN_STATE_RUNNING)) {
> +        /* Make sure all file formats flush their mutable metadata.
> +         * If we get an error here, just don't restart the VM yet. */
> +        bdrv_invalidate_cache_all(&local_err);
> +        if (local_err) {
> +            error_report_err(local_err);
> +            local_err = NULL;
> +            autostart = false;
> +        }
>      }
>  
>      /*
> -- 
> 2.14.3
> 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK