[PATCH V2 09/11] migration: notifier error checking

[Steve Sistare <steven.sistare@oracle.com>]

Check the status returned by migration notifiers and report errors.
If notifiers fail, call the notifiers again so they can clean up.
None of the notifiers return an error status at this time.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
 include/migration/misc.h |  2 +-
 migration/migration.c    | 37 ++++++++++++++++++++++++++++---------
 2 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/include/migration/misc.h b/include/migration/misc.h
index e79694f..782bdec 100644
--- a/include/migration/misc.h
+++ b/include/migration/misc.h
@@ -73,7 +73,7 @@ void migration_add_notifier(NotifierWithReturn *notify,
 void migration_add_notifier_mode(NotifierWithReturn *notify,
                                  MigrationNotifyFunc func, MigMode mode);
 void migration_remove_notifier(NotifierWithReturn *notify);
-void migration_call_notifiers(MigrationState *s);
+int migration_call_notifiers(MigrationState *s, Error **errp);
 bool migration_in_setup(MigrationState *);
 bool migration_has_finished(MigrationState *);
 bool migration_has_failed(MigrationState *);
diff --git a/migration/migration.c b/migration/migration.c
index c828ba7..86a5a94 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -1274,6 +1274,8 @@ void migrate_set_state(int *state, int old_state, int new_state)
 
 static void migrate_fd_cleanup(MigrationState *s)
 {
+    Error *local_err = NULL;
+
     qemu_bh_delete(s->cleanup_bh);
     s->cleanup_bh = NULL;
 
@@ -1321,11 +1323,23 @@ static void migrate_fd_cleanup(MigrationState *s)
                           MIGRATION_STATUS_CANCELLED);
     }
 
+    if (!migration_has_failed(s) &&
+        migration_call_notifiers(s, &local_err)) {
+
+        migrate_set_state(&s->state, s->state, MIGRATION_STATUS_FAILED);
+        migrate_set_error(s, local_err);
+        error_free(local_err);
+    }
+
     if (s->error) {
         /* It is used on info migrate.  We can't free it */
         error_report_err(error_copy(s->error));
     }
-    migration_call_notifiers(s);
+
+    if (migration_has_failed(s)) {
+        migration_call_notifiers(s, NULL);
+    }
+
     block_cleanup_parameters();
     yank_unregister_instance(MIGRATION_YANK_INSTANCE);
 }
@@ -1450,13 +1464,14 @@ void migration_remove_notifier(NotifierWithReturn *notify)
     }
 }
 
-void migration_call_notifiers(MigrationState *s)
+int migration_call_notifiers(MigrationState *s, Error **errp)
 {
     MigMode mode = s->parameters.mode;
     MigrationEvent e;
 
     e.state = s->state;
-    notifier_with_return_list_notify(&migration_state_notifiers[mode], &e, 0);
+    return notifier_with_return_list_notify(&migration_state_notifiers[mode],
+                                            &e, errp);
 }
 
 bool migration_in_setup(MigrationState *s)
@@ -2520,7 +2535,9 @@ static int postcopy_start(MigrationState *ms, Error **errp)
      * spice needs to trigger a transition now
      */
     ms->postcopy_after_devices = true;
-    migration_call_notifiers(ms);
+    if (migration_call_notifiers(ms, errp)) {
+        goto fail;
+    }
 
     migration_downtime_end(ms);
 
@@ -2540,11 +2557,10 @@ static int postcopy_start(MigrationState *ms, Error **errp)
 
     ret = qemu_file_get_error(ms->to_dst_file);
     if (ret) {
-        error_setg(errp, "postcopy_start: Migration stream errored");
-        migrate_set_state(&ms->state, MIGRATION_STATUS_POSTCOPY_ACTIVE,
-                              MIGRATION_STATUS_FAILED);
+        error_setg_errno(errp, -ret, "postcopy_start: Migration stream error");
+        bql_lock();
+        goto fail;
     }
-
     trace_postcopy_preempt_enabled(migrate_postcopy_preempt());
 
     return ret;
@@ -2565,6 +2581,7 @@ fail:
             error_report_err(local_err);
         }
     }
+    migration_call_notifiers(ms, NULL);         /* Notify about failure */
     bql_unlock();
     return -1;
 }
@@ -3590,7 +3607,9 @@ void migrate_fd_connect(MigrationState *s, Error *error_in)
         rate_limit = migrate_max_bandwidth();
 
         /* Notify before starting migration thread */
-        migration_call_notifiers(s);
+        if (migration_call_notifiers(s, &local_err)) {
+            goto fail;
+        }
     }
 
     migration_rate_set(rate_limit);
-- 
1.8.3.1