migration: migrate 'inc' command option is deprecated.

Use blockdev-mirror with NBD instead.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20231018115513.2163-3-quintela@redhat.com>

docs/about/deprecated.rst

@@ -469,3 +469,11 @@ Migration
 ``skipped`` field in Migration stats has been deprecated.  It hasn't
 been used for more than 10 years.
 
+``inc`` migrate command option (since 8.2)
+''''''''''''''''''''''''''''''''''''''''''
+
+Use blockdev-mirror with NBD instead.
+
+As an intermediate step the ``inc`` functionality can be achieved by
+setting the ``block-incremental`` migration parameter to ``true``.
+But this parameter is also deprecated.

migration/migration-hmp-cmds.c

@@ -745,6 +745,11 @@ void hmp_migrate(Monitor *mon, const QDict *qdict)
     const char *uri = qdict_get_str(qdict, "uri");
     Error *err = NULL;
 
+    if (inc) {
+        warn_report("option '-i' is deprecated;"
+                    " use blockdev-mirror with NBD instead");
+    }
+
     qmp_migrate(uri, !!blk, blk, !!inc, inc,
                 false, false, true, resume, &err);
     if (hmp_handle_error(mon, err)) {

migration/migration.c

@@ -1620,6 +1620,11 @@ static bool migrate_prepare(MigrationState *s, bool blk, bool blk_inc,
 {
     Error *local_err = NULL;
 
+    if (blk_inc) {
+        warn_report("parameter 'inc' is deprecated;"
+                    " use blockdev-mirror with NBD instead");
+    }
+
     if (resume) {
         if (s->state != MIGRATION_STATUS_POSTCOPY_PAUSED) {
             error_setg(errp, "Cannot resume if there is no "

qapi/migration.json

@@ -1524,6 +1524,11 @@
 #
 # @resume: resume one paused migration, default "off". (since 3.0)
 #
+# Features:
+#
+# @deprecated: Member @inc is deprecated.  Use blockdev-mirror with
+#     NBD instead.
+#
 # Returns: nothing on success
 #
 # Since: 0.14
@@ -1545,7 +1550,8 @@
 # <- { "return": {} }
 ##
 { 'command': 'migrate',
-  'data': {'uri': 'str', '*blk': 'bool', '*inc': 'bool',
+  'data': {'uri': 'str', '*blk': 'bool',
+           '*inc': { 'type': 'bool', 'features': [ 'deprecated' ] },
            '*detach': 'bool', '*resume': 'bool' } }
 
 ##