[Qemu-devel] [PATCH COLO-Frame v9 22/32] qmp event: Add event notification for COLO error

[zhanghailiang]

If some errors happen during VM's COLO FT stage, it's important to notify the 
users
of this event. Together with 'colo_lost_heartbeat', users can intervene in 
COLO's
failover work immediately.
If users don't want to get involved in COLO's failover verdict,
it is still necessary to notify users that we exit COLO mode.

Cc: Markus Armbruster <address@hidden>
Cc: Michael Roth <address@hidden>
Signed-off-by: zhanghailiang <address@hidden>
Signed-off-by: Li Zhijian <address@hidden>
---
 docs/qmp/qmp-events.txt | 17 +++++++++++++++++
 migration/colo.c        | 17 +++++++++++++----
 qapi-schema.json        | 16 ++++++++++++++++
 qapi/event.json         | 17 +++++++++++++++++
 4 files changed, 63 insertions(+), 4 deletions(-)

diff --git a/docs/qmp/qmp-events.txt b/docs/qmp/qmp-events.txt
index d92cc48..0bd7c41 100644
--- a/docs/qmp/qmp-events.txt
+++ b/docs/qmp/qmp-events.txt
@@ -182,6 +182,23 @@ Example:
 Note: The "ready to complete" status is always reset by a BLOCK_JOB_ERROR
 event.
 
+COLO_EXIT
+---------
+
+Emitted when VM finishes COLO mode due to some errors happening or
+the request of users.
+
+Data:
+
+ - "mode": COLO mode, primary or secondary side (json-string)
+ - "reason":  the exit reason, internal error or external request. 
(json-string)
+ - "error": error message (json-string, operation)
+
+Example:
+
+{"timestamp": {"seconds": 2032141960, "microseconds": 417172},
+ "event": "COLO_EXIT", "data": {"mode": "primary", "reason": "request" } }
+
 DEVICE_DELETED
 --------------
 
diff --git a/migration/colo.c b/migration/colo.c
index 9ad285c..29b5334 100644
--- a/migration/colo.c
+++ b/migration/colo.c
@@ -18,6 +18,7 @@
 #include "qemu/error-report.h"
 #include "qemu/sockets.h"
 #include "migration/failover.h"
+#include "qapi-event.h"
 
 /*
  * checkpoint interval: unit ms
@@ -347,6 +348,9 @@ out:
     current_time = error_time = qemu_clock_get_ms(QEMU_CLOCK_HOST);
     if (ret < 0) {
         error_report("Detect some error: %s", strerror(-ret));
+        qapi_event_send_colo_exit(COLO_MODE_PRIMARY, COLO_EXIT_REASON_ERROR,
+                                  true, strerror(-ret), NULL);
+
         /* Give users time to get involved in this verdict */
         while (current_time - error_time <= DEFAULT_FAILOVER_DELAY) {
             if (failover_request_is_active()) {
@@ -363,15 +367,14 @@ out:
             failover_request_active(NULL);
         }
         qemu_mutex_unlock_iothread();
+    } else {
+        qapi_event_send_colo_exit(COLO_MODE_PRIMARY, COLO_EXIT_REASON_REQUEST,
+                                  false, NULL, NULL);
     }
 
     qsb_free(buffer);
     buffer = NULL;
 
-   if (s->from_dst_file) {
-        qemu_fclose(s->from_dst_file);
-    }
-
     return NULL;
 }
 
@@ -552,6 +555,9 @@ out:
     if (ret < 0) {
         error_report("colo incoming thread will exit, detect error: %s",
                      strerror(-ret));
+        qapi_event_send_colo_exit(COLO_MODE_SECONDARY, COLO_EXIT_REASON_ERROR,
+                                  true, strerror(-ret), NULL);
+
         /* Give users time to get involved in this verdict */
         while (current_time - error_time <= DEFAULT_FAILOVER_DELAY) {
             if (failover_request_is_active()) {
@@ -570,6 +576,9 @@ out:
             error_report("SVM is going to exit in default!");
             exit(1);
         }
+    } else {
+        qapi_event_send_colo_exit(COLO_MODE_SECONDARY, 
COLO_EXIT_REASON_REQUEST,
+                                  false, NULL, NULL);
     }
 
     if (fb) {
diff --git a/qapi-schema.json b/qapi-schema.json
index 8468552..f75e96b 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -712,6 +712,22 @@
   'data': [ 'unknown', 'primary', 'secondary'] }
 
 ##
+# @COLOExitReason
+#
+# The reason of COLO exit
+#
+# @unknow: unknown reason
+#
+# @request: COLO exit is due to an external request
+#
+# @error: COLO exit is due to an internal error
+#
+# Since: 2.5
+##
+{ 'enum': 'COLOExitReason',
+  'data': [ 'unknown', 'request', 'error'] }
+
+##
 # @colo-lost-heartbeat
 #
 # Tell qemu that heartbeat is lost, request it to do takeover procedures.
diff --git a/qapi/event.json b/qapi/event.json
index f0cef01..6158ab5 100644
--- a/qapi/event.json
+++ b/qapi/event.json
@@ -255,6 +255,23 @@
   'data': {'status': 'MigrationStatus'}}
 
 ##
+# @COLO_EXIT
+#
+# Emitted when VM finishes COLO mode due to some errors happening or
+# the request of users.
+#
+# @mode: @COLOMode describing which side of VM is exit.
+#
+# @reason: @COLOExitReason describing the reason of colo exit.
+#
+# @error: #optional, error message. Only present on error happening.
+#
+# Since: 2.5
+##
+{ 'event': 'COLO_EXIT',
+  'data': {'mode': 'COLOMode', 'reason': 'COLOExitReason', '*error': 'str' } }
+
+##
 # @ACPI_DEVICE_OST
 #
 # Emitted when guest executes ACPI _OST method.
-- 
1.8.3.1