[COLO-Frame,v18,20/34] qmp event: Add COLO_EXIT event to notify users while exited from COLO

Commit Message

Zhanghailiang Aug. 3, 2016, 12:25 p.m. UTC

If some errors happen during VM's COLO FT stage, it's important to
notify the users of this event. Together with 'x_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 exited COLO mode.

Cc: Markus Armbruster <[e-mail]>
Cc: Michael Roth <[e-mail]>
Signed-off-by: zhanghailiang <[e-mail]>
Signed-off-by: Li Zhijian <[e-mail]>
Reviewed-by: Eric Blake <[e-mail]>
---
v16:
- fix some minor grammars from Eric
- Add Reviewed-by tag
v13:
- Remove optional 'error' string for this event.
  (I doubted it was usefull for users, Since users shouldn't
   interpret it and can't depend on it to decide what happened
   exaclty. Besides it is really hard to organize.)
- Remove unused 'unknown' member for enum COLOExitReason.
 (Eric's suggestion)
- Fix comment for COLO_EXIT
v11:
- Fix several typos found by Eric
---
 docs/qmp-events.txt | 16 ++++++++++++++++
 migration/colo.c    | 19 +++++++++++++++++++
 qapi-schema.json    | 14 ++++++++++++++
 qapi/event.json     | 15 +++++++++++++++
 4 files changed, 64 insertions(+)

Patch

diff --git a/docs/qmp-events.txt b/docs/qmp-events.txt
index 7967ec4..02dd521 100644
--- a/docs/qmp-events.txt
+++ b/docs/qmp-events.txt
@@ -188,6 +188,22 @@  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
+at 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)
+
+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 eeef775..f8fce0d 100644
--- a/migration/colo.c
+++ b/migration/colo.c
@@ -19,6 +19,7 @@ 
 #include "qemu/error-report.h"
 #include "qapi/error.h"
 #include "migration/failover.h"
+#include "qapi-event.h"
 
 #define COLO_BUFFER_BASE_SIZE (4 * 1024 * 1024)
 
@@ -361,6 +362,17 @@  out:
     }
 
     qemu_fclose(fb);
+    /*
+     * There are only two reasons we can go here, some error happened.
+     * Or the user triggered failover.
+     */
+    if (!failover_request_is_active()) {
+        qapi_event_send_colo_exit(COLO_MODE_PRIMARY,
+                                  COLO_EXIT_REASON_ERROR, NULL);
+    } else {
+        qapi_event_send_colo_exit(COLO_MODE_PRIMARY,
+                                  COLO_EXIT_REASON_REQUEST, NULL);
+    }
 
     if (s->rp_state.from_dst_file) {
         qemu_fclose(s->rp_state.from_dst_file);
@@ -520,6 +532,13 @@  out:
     if (local_err) {
         error_report_err(local_err);
     }
+    if (!failover_request_is_active()) {
+        qapi_event_send_colo_exit(COLO_MODE_SECONDARY,
+                                  COLO_EXIT_REASON_ERROR, NULL);
+    } else {
+        qapi_event_send_colo_exit(COLO_MODE_SECONDARY,
+                                  COLO_EXIT_REASON_REQUEST, NULL);
+    }
 
     if (fb) {
         qemu_fclose(fb);
diff --git a/qapi-schema.json b/qapi-schema.json
index ee7131d..d729b61 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -835,6 +835,20 @@ 
   'data': [ 'unknown', 'primary', 'secondary'] }
 
 ##
+# @COLOExitReason
+#
+# The reason for a COLO exit
+#
+# @request: COLO exit is due to an external request
+#
+# @error: COLO exit is due to an internal error
+#
+# Since: 2.8
+##
+{ 'enum': 'COLOExitReason',
+  'data': [ 'request', 'error' ] }
+
+##
 # @x-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 8642052..88d10e7 100644
--- a/qapi/event.json
+++ b/qapi/event.json
@@ -268,6 +268,21 @@ 
   'data': { 'pass': 'int' } }
 
 ##
+# @COLO_EXIT
+#
+# Emitted when VM finishes COLO mode due to some errors happening or
+# at the request of users.
+#
+# @mode: which COLO mode the VM was in when it exited.
+#
+# @reason: describes the reason for the COLO exit.
+#
+# Since: 2.8
+##
+{ 'event': 'COLO_EXIT',
+  'data': {'mode': 'COLOMode', 'reason': 'COLOExitReason' } }
+
+##
 # @ACPI_DEVICE_OST
 #
 # Emitted when guest executes ACPI _OST method.