[PATCH v2 2/2] qapi: introduce exit-on-error paramter for migrate-incoming

[Vladimir Sementsov-Ogievskiy]

Now we do set MIGRATION_FAILED state, but don't give a chance to
orchestrator to query migration state and get the error.

Let's provide a possibility for QMP-based orchestrators to get an error
like with outgoing migration.

For x-exit-preconfig we can enable new behavior unconditionally, as
it's an unstable command.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
---
 migration/migration-hmp-cmds.c |  2 +-
 migration/migration.c          | 31 +++++++++++++++++++++----------
 migration/migration.h          |  3 +++
 qapi/migration.json            |  7 ++++++-
 system/vl.c                    |  7 +------
 5 files changed, 32 insertions(+), 18 deletions(-)

diff --git a/migration/migration-hmp-cmds.c b/migration/migration-hmp-cmds.c
index 7e96ae6ffd..9c94a18029 100644
--- a/migration/migration-hmp-cmds.c
+++ b/migration/migration-hmp-cmds.c
@@ -466,7 +466,7 @@ void hmp_migrate_incoming(Monitor *mon, const QDict *qdict)
     }
     QAPI_LIST_PREPEND(caps, g_steal_pointer(&channel));
 
-    qmp_migrate_incoming(NULL, true, caps, &err);
+    qmp_migrate_incoming(NULL, true, caps, true, true, &err);
     qapi_free_MigrationChannelList(caps);
 
 end:
diff --git a/migration/migration.c b/migration/migration.c
index 806b7b080b..fe72529ba7 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -234,6 +234,8 @@ void migration_object_init(void)
     qemu_cond_init(&current_incoming->page_request_cond);
     current_incoming->page_requested = g_tree_new(page_request_addr_cmp);
 
+    current_incoming->exit_on_error = true;
+
     migration_object_check(current_migration, &error_fatal);
 
     blk_mig_init();
@@ -597,12 +599,15 @@ bool migrate_uri_parse(const char *uri, MigrationChannel 
**channel,
 
 static void qemu_start_incoming_migration(const char *uri, bool has_channels,
                                           MigrationChannelList *channels,
+                                          bool exit_on_error,
                                           Error **errp)
 {
     g_autoptr(MigrationChannel) channel = NULL;
     MigrationAddress *addr = NULL;
     MigrationIncomingState *mis = migration_incoming_get_current();
 
+    mis->exit_on_error = exit_on_error;
+
     /*
      * Having preliminary checks for uri and channel
      */
@@ -738,11 +743,12 @@ process_incoming_migration_co(void *opaque)
     MigrationIncomingState *mis = migration_incoming_get_current();
     PostcopyState ps;
     int ret;
+    Error *local_err = NULL;
 
     assert(mis->from_src_file);
 
     if (compress_threads_load_setup(mis->from_src_file)) {
-        error_report("Failed to setup decompress threads");
+        error_setg(&local_err, "Failed to setup decompress threads");
         goto fail;
     }
 
@@ -779,25 +785,26 @@ process_incoming_migration_co(void *opaque)
     }
 
     if (ret < 0) {
-        error_report("load of migration failed: %s", strerror(-ret));
+        error_setg(&local_err, "load of migration failed: %s", strerror(-ret));
         goto fail;
     }
 
     if (colo_incoming_co() < 0) {
+        error_setg(&local_err, "colo incoming failed");
         goto fail;
     }
 
     migration_bh_schedule(process_incoming_migration_bh, mis);
     return;
 fail:
+    migrate_report_err(local_err);
     migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,
                       MIGRATION_STATUS_FAILED);
-    qemu_fclose(mis->from_src_file);
-
-    multifd_recv_cleanup();
-    compress_threads_load_cleanup();
+    migration_incoming_state_destroy();
 
-    exit(EXIT_FAILURE);
+    if (mis->exit_on_error) {
+        exit(EXIT_FAILURE);
+    }
 }
 
 /**
@@ -1785,7 +1792,9 @@ void migrate_del_blocker(Error **reasonp)
 }
 
 void qmp_migrate_incoming(const char *uri, bool has_channels,
-                          MigrationChannelList *channels, Error **errp)
+                          MigrationChannelList *channels,
+                          bool has_exit_on_error, bool exit_on_error,
+                          Error **errp)
 {
     Error *local_err = NULL;
     static bool once = true;
@@ -1803,7 +1812,9 @@ void qmp_migrate_incoming(const char *uri, bool 
has_channels,
         return;
     }
 
-    qemu_start_incoming_migration(uri, has_channels, channels, &local_err);
+    qemu_start_incoming_migration(uri, has_channels, channels,
+                                  has_exit_on_error ? exit_on_error : true,
+                                  &local_err);
 
     if (local_err) {
         yank_unregister_instance(MIGRATION_YANK_INSTANCE);
@@ -1839,7 +1850,7 @@ void qmp_migrate_recover(const char *uri, Error **errp)
      * only re-setup the migration stream and poke existing migration
      * to continue using that newly established channel.
      */
-    qemu_start_incoming_migration(uri, false, NULL, errp);
+    qemu_start_incoming_migration(uri, false, NULL, mis->exit_on_error, errp);
 }
 
 void qmp_migrate_pause(Error **errp)
diff --git a/migration/migration.h b/migration/migration.h
index f9f436c33e..089f710ee1 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -227,6 +227,9 @@ struct MigrationIncomingState {
      * is needed as this field is updated serially.
      */
     unsigned int switchover_ack_pending_num;
+
+    /* Do exit on incoming migration failure */
+    bool exit_on_error;
 };
 
 MigrationIncomingState *migration_incoming_get_current(void);
diff --git a/qapi/migration.json b/qapi/migration.json
index 8c65b90328..9de8b98d0b 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -1837,6 +1837,10 @@
 # @channels: list of migration stream channels with each stream in the
 #     list connected to a destination interface endpoint.
 #
+# @exit-on-error: Do exit on incoming migration failure.  Default true.
+#     When set to false, the error is reported by MIGRATION event and
+#     error could be retrieved by query-migrate command.  (since 9.1)
+#
 # Since: 2.3
 #
 # Notes:
@@ -1889,7 +1893,8 @@
 ##
 { 'command': 'migrate-incoming',
              'data': {'*uri': 'str',
-                      '*channels': [ 'MigrationChannel' ] } }
+                      '*channels': [ 'MigrationChannel' ],
+                      '*exit-on-error': 'bool' } }
 
 ##
 # @xen-save-devices-state:
diff --git a/system/vl.c b/system/vl.c
index c644222982..f5b4c18200 100644
--- a/system/vl.c
+++ b/system/vl.c
@@ -2718,13 +2718,8 @@ void qmp_x_exit_preconfig(Error **errp)
     }
 
     if (incoming) {
-        Error *local_err = NULL;
         if (strcmp(incoming, "defer") != 0) {
-            qmp_migrate_incoming(incoming, false, NULL, &local_err);
-            if (local_err) {
-                error_reportf_err(local_err, "-incoming %s: ", incoming);
-                exit(1);
-            }
+            qmp_migrate_incoming(incoming, false, NULL, true, true, errp);
         }
     } else if (autostart) {
         qmp_cont(NULL);
-- 
2.34.1