[v3,01/10] migration: Display error in query-migrate irrelevant of status

Commit Message

Peter Xu Oct. 4, 2023, 10:02 p.m. UTC

Display it as long as being set, irrelevant of FAILED status.  E.g., it may
also be applicable to PAUSED stage of postcopy, to provide hint on what has
gone wrong.

The error_mutex seems to be overlooked when referencing the error, add it
to be very safe.

This will change QAPI behavior by showing up error message outside !FAILED
status, but it's intended and doesn't expect to break anyone.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2018404
Reviewed-by: Fabiano Rosas <[e-mail]>
Signed-off-by: Peter Xu <[e-mail]>
---
 qapi/migration.json   | 5 ++---
 migration/migration.c | 8 +++++---
 2 files changed, 7 insertions(+), 6 deletions(-)

Comments

Juan Quintela Oct. 5, 2023, 7:28 a.m. UTC | #1

Peter Xu <[e-mail]> wrote:
> Display it as long as being set, irrelevant of FAILED status.  E.g., it may
> also be applicable to PAUSED stage of postcopy, to provide hint on what has
> gone wrong.
>
> The error_mutex seems to be overlooked when referencing the error, add it
> to be very safe.
>
> This will change QAPI behavior by showing up error message outside !FAILED
> status, but it's intended and doesn't expect to break anyone.
>
> Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2018404
> Reviewed-by: Fabiano Rosas <[e-mail]>
> Signed-off-by: Peter Xu <[e-mail]>

Reviewed-by: Juan Quintela <[e-mail]>

queued.

Patch

diff --git a/qapi/migration.json b/qapi/migration.json
index 8843e74b59..c241b6d318 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -230,9 +230,8 @@ 
 #     throttled during auto-converge.  This is only present when
 #     auto-converge has started throttling guest cpus.  (Since 2.7)
 #
-# @error-desc: the human readable error description string, when
-#     @status is 'failed'. Clients should not attempt to parse the
-#     error strings.  (Since 2.7)
+# @error-desc: the human readable error description string. Clients
+#     should not attempt to parse the error strings.  (Since 2.7)
 #
 # @postcopy-blocktime: total time when all vCPU were blocked during
 #     postcopy live migration.  This is only present when the
diff --git a/migration/migration.c b/migration/migration.c
index 585d3c8f55..010056d6f3 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -1057,9 +1057,6 @@  static void fill_source_migration_info(MigrationInfo *info)
         break;
     case MIGRATION_STATUS_FAILED:
         info->has_status = true;
-        if (s->error) {
-            info->error_desc = g_strdup(error_get_pretty(s->error));
-        }
         break;
     case MIGRATION_STATUS_CANCELLED:
         info->has_status = true;
@@ -1069,6 +1066,11 @@  static void fill_source_migration_info(MigrationInfo *info)
         break;
     }
     info->status = state;
+
+    QEMU_LOCK_GUARD(&s->error_mutex);
+    if (s->error) {
+        info->error_desc = g_strdup(error_get_pretty(s->error));
+    }
 }
 
 static void fill_destination_migration_info(MigrationInfo *info)