Re: [Qemu-devel] [PATCH V8 1/2] Add a new qmp command to start/stop replication

[Eric Blake]

On 02/23/2017 01:14 AM, Zhang Chen wrote:
> We can call this qmp command to start/stop replication outside of qemu.
> Like Xen colo need this function.
> 
> Signed-off-by: Zhang Chen <address@hidden>
> Signed-off-by: Wen Congyang <address@hidden>
> Reviewed-by: Eric Blake <address@hidden>
> Reviewed-by: Stefano Stabellini <address@hidden>
> Reviewed-by: zhanghailiang <address@hidden>
> 
> ---

> @@ -104,6 +106,27 @@ void colo_do_failover(MigrationState *s)
>      }
>  }
>  
> +void qmp_xen_set_replication(bool enable, bool primary,
> +                             bool has_failover, bool failover,
> +                             Error **errp)
> +{
> +    ReplicationMode mode = primary ?
> +                           REPLICATION_MODE_PRIMARY :
> +                           REPLICATION_MODE_SECONDARY;
> +
> +    if (has_failover && enable) {
> +        error_setg(errp, "Parameter 'failover' is only for"
> +                   " stopping replication");
> +        return;
> +    }
> +
> +    if (enable) {
> +        replication_start_all(mode, errp);
> +    } else {
> +        replication_stop_all(failover, failover ? NULL : errp);

Technically, this is use of failover without first checking
has_failover; it would be safer if you inserted:

if (!has_failover) {
    failover = NULL;
}

earlier in the function to be safe against any callers that don't go
through the QAPI-generated code.  Fortunately, our QAPI generated code
guarantees that failover is NULL when has_failover is false, so my R-b
can stand as-is if there is no other reason for a respin.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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