[RFC 04/15] qapi: block-job-change: make copy-mode parameter optional

[Vladimir Sementsov-Ogievskiy]

We are going to add more parameters to change. We want to make possible
to change only one or any subset of available options. So all the
options should be optional.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
---
 block/mirror.c       | 5 +++++
 qapi/block-core.json | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/block/mirror.c b/block/mirror.c
index a177502e4f..2d0cd22c06 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -1265,6 +1265,11 @@ static void mirror_change(BlockJob *job, 
JobChangeOptions *opts,
 
     GLOBAL_STATE_CODE();
 
+    if (!change_opts->has_copy_mode) {
+        /* Nothing to do */
+        return;
+    }
+
     if (qatomic_read(&s->copy_mode) == change_opts->copy_mode) {
         return;
     }
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 67dd0ef038..6041e7bd8f 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -3071,7 +3071,7 @@
 # Since: 8.2
 ##
 { 'struct': 'JobChangeOptionsMirror',
-  'data': { 'copy-mode' : 'MirrorCopyMode' } }
+  'data': { '*copy-mode' : 'MirrorCopyMode' } }
 
 ##
 # @JobChangeOptions:
-- 
2.34.1