We can call this qmp command to start/stop replication outside of qemu.
Like Xen colo need this function.

Signed-off-by: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
Signed-off-by: Wen Congyang <wencongyang@gmail.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: zhanghailiang <zhang.zhanghailiang@huawei.com>

---
 migration/colo.c | 23 +++++++++++++++++++++++
 qapi-schema.json | 25 +++++++++++++++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/migration/colo.c b/migration/colo.c
index 93c85c5..6fc2ade 100644
--- a/migration/colo.c
+++ b/migration/colo.c
@@ -19,6 +19,8 @@
 #include "qemu/error-report.h"
 #include "qapi/error.h"
 #include "migration/failover.h"
+#include "replication.h"
+#include "qmp-commands.h"
 
 #define COLO_BUFFER_BASE_SIZE (4 * 1024 * 1024)
 
@@ -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);
+    }
+}
+
 static void colo_send_message(QEMUFile *f, COLOMessage msg,
                               Error **errp)
 {
diff --git a/qapi-schema.json b/qapi-schema.json
index cbdffdd..9445b93 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -5906,6 +5906,31 @@
 { 'command': 'xen-load-devices-state', 'data': {'filename': 'str'} }
 
 ##
+# @xen-set-replication:
+#
+# Enable or disable replication.
+#
+# @enable: true to enable, false to disable.
+#
+# @primary: true for primary or false for secondary.
+#
+# @failover: #optional true to do failover, false to stop. but cannot be
+#            specified if 'enable' is true. default value is false.
+#
+# Returns: nothing.
+#
+# Example:
+#
+# -> { "execute": "xen-set-replication",
+#      "arguments": {"enable": true, "primary": false} }
+# <- { "return": {} }
+#
+# Since: 2.9
+##
+{ 'command': 'xen-set-replication',
+  'data': { 'enable': 'bool', 'primary': 'bool', '*failover' : 'bool' } }
+
+##
 # @GICCapability:
 #
 # The struct describes capability for a specific GIC (Generic
-- 
2.7.4

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 <zhangchen.fnst@cn.fujitsu.com>
> Signed-off-by: Wen Congyang <wencongyang@gmail.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>
> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
> Reviewed-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
> 
> ---

> @@ -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

On 02/23/2017 11:31 PM, Eric Blake wrote:
> 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 <zhangchen.fnst@cn.fujitsu.com>
>> Signed-off-by: Wen Congyang <wencongyang@gmail.com>
>> Reviewed-by: Eric Blake <eblake@redhat.com>
>> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
>> Reviewed-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
>>
>> ---
>> @@ -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;
> }

OK, I will insert this code in next version.

Thanks
Zhang Chen

> 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.

-- 
Thanks
Zhang Chen