COLO: Don't process failover request while loading VM's state

We should not do failover work while the main thread is loading
VM's state. Otherwise the consistent of VM's memory and
device state will be broken.

We will restart the loading process after jump over the stage,
The new failover status 'RELAUNCH' will help to record if we
need to restart the process.

Cc: Eric Blake <eblake@redhat.com>
Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <1484657864-21708-4-git-send-email-zhang.zhanghailiang@huawei.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
   Added a missing '(Since 2.9)'

diff --git a/migration/colo.c b/migration/colo.c
index 3222812d96509f18deccab9a0cc4cba5b036c71e..712308ed5efd97c5714c0f1995502572753a2b37 100644 (file)
--- a/migration/colo.c
+++ b/migration/colo.c
@@ -20,6 +20,8 @@
 #include "qapi/error.h"
 #include "migration/failover.h"
 
+static bool vmstate_loading;
+
 #define COLO_BUFFER_BASE_SIZE (4 * 1024 * 1024)
 
 bool colo_supported(void)
@@ -51,6 +53,19 @@ static void secondary_vm_do_failover(void)
     int old_state;
     MigrationIncomingState *mis = migration_incoming_get_current();
 
+    /* Can not do failover during the process of VM's loading VMstate, Or
+     * it will break the secondary VM.
+     */
+    if (vmstate_loading) {
+        old_state = failover_set_state(FAILOVER_STATUS_ACTIVE,
+                        FAILOVER_STATUS_RELAUNCH);
+        if (old_state != FAILOVER_STATUS_ACTIVE) {
+            error_report("Unknown error while do failover for secondary VM,"
+                         "old_state: %s", FailoverStatus_lookup[old_state]);
+        }
+        return;
+    }
+
     migrate_set_state(&mis->state, MIGRATION_STATUS_COLO,
                       MIGRATION_STATUS_COMPLETED);
 
@@ -548,13 +563,23 @@ void *colo_process_incoming_thread(void *opaque)
 
         qemu_mutex_lock_iothread();
         qemu_system_reset(VMRESET_SILENT);
+        vmstate_loading = true;
         if (qemu_loadvm_state(fb) < 0) {
             error_report("COLO: loadvm failed");
             qemu_mutex_unlock_iothread();
             goto out;
         }
+
+        vmstate_loading = false;
         qemu_mutex_unlock_iothread();
 
+        if (failover_get_state() == FAILOVER_STATUS_RELAUNCH) {
+            failover_set_state(FAILOVER_STATUS_RELAUNCH,
+                            FAILOVER_STATUS_NONE);
+            failover_request_active(NULL);
+            goto out;
+        }
+
         colo_send_message(mis->to_src_file, COLO_MESSAGE_VMSTATE_LOADED,
                      &local_err);
         if (local_err) {
@@ -563,6 +588,7 @@ void *colo_process_incoming_thread(void *opaque)
     }
 
 out:
+    vmstate_loading = false;
     /* Throw the unreported error message after exited from loop */
     if (local_err) {
         error_report_err(local_err);

diff --git a/qapi-schema.json b/qapi-schema.json
index 93305412dd47f0dd5000721b3610b67c193dcd95..5edb08d621d90e868a1bd9e534cf57a7f7406ac0 100644 (file)
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -1193,10 +1193,12 @@
 #
 # @completed: finish the process of failover
 #
+# @relaunch: restart the failover process, from 'none' -> 'completed' (Since 2.9)
+#
 # Since: 2.8
 ##
 { 'enum': 'FailoverStatus',
-  'data': [ 'none', 'require', 'active', 'completed'] }
+  'data': [ 'none', 'require', 'active', 'completed', 'relaunch' ] }
 
 ##
 # @x-colo-lost-heartbeat: