[Qemu-devel] [PULL 14/15] Migration/colo.c: Make user obtain the last COLO mode info after failover

[Juan Quintela]

From: Zhang Chen <address@hidden>

Add the last_colo_mode to save the status after failover.
This patch can solve the issue that user want to get last colo mode
use query_colo_status after failover.

Signed-off-by: Zhang Chen <address@hidden>
Reviewed-by: Juan Quintela <address@hidden>
Signed-off-by: Juan Quintela <address@hidden>
---
 migration/colo.c    | 16 ++++++++++++++++
 qapi/migration.json |  7 ++++++-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/migration/colo.c b/migration/colo.c
index d1ae2e6d11..238a6d62c7 100644
--- a/migration/colo.c
+++ b/migration/colo.c
@@ -38,6 +38,9 @@
 static bool vmstate_loading;
 static Notifier packets_compare_notifier;
 
+/* User need to know colo mode after COLO failover */
+static COLOMode last_colo_mode;
+
 #define COLO_BUFFER_BASE_SIZE (4 * 1024 * 1024)
 
 bool migration_in_colo_state(void)
@@ -264,6 +267,7 @@ COLOStatus *qmp_query_colo_status(Error **errp)
     COLOStatus *s = g_new0(COLOStatus, 1);
 
     s->mode = get_colo_mode();
+    s->last_mode = last_colo_mode;
 
     switch (failover_get_state()) {
     case FAILOVER_STATUS_NONE:
@@ -515,6 +519,12 @@ static void colo_process_checkpoint(MigrationState *s)
     Error *local_err = NULL;
     int ret;
 
+    last_colo_mode = get_colo_mode();
+    if (last_colo_mode != COLO_MODE_PRIMARY) {
+        error_report("COLO mode must be COLO_MODE_PRIMARY");
+        return;
+    }
+
     failover_init_state();
 
     s->rp_state.from_dst_file = qemu_file_get_return_path(s->to_dst_file);
@@ -688,6 +698,12 @@ void *colo_process_incoming_thread(void *opaque)
     migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,
                       MIGRATION_STATUS_COLO);
 
+    last_colo_mode = get_colo_mode();
+    if (last_colo_mode != COLO_MODE_SECONDARY) {
+        error_report("COLO mode must be COLO_MODE_SECONDARY");
+        return NULL;
+    }
+
     failover_init_state();
 
     mis->to_src_file = qemu_file_get_return_path(mis->from_src_file);
diff --git a/qapi/migration.json b/qapi/migration.json
index e383951765..cfde29acf8 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -1380,12 +1380,17 @@
 # @mode: COLO running mode. If COLO is running, this field will return
 #        'primary' or 'secondary'.
 #
+# @last_mode: COLO last running mode. If COLO is running, this field
+#             will return same like mode field, after failover we can
+#             use this field to get last colo mode. (since 4.1)
+#
 # @reason: describes the reason for the COLO exit.
 #
 # Since: 3.1
 ##
 { 'struct': 'COLOStatus',
-  'data': { 'mode': 'COLOMode', 'reason': 'COLOExitReason' } }
+  'data': { 'mode': 'COLOMode', 'last_mode': 'COLOMode',
+            'reason': 'COLOExitReason' } }
 
 ##
 # @query-colo-status:
-- 
2.20.1