commit fe44dc91807eca59d0230fe828c1e2ee0c305a1e
author Ashijeet Acharya <ashijeetacharya@gmail.com> Mon Jan 16 17:01:53 2017 +0530
committer Dr. David Alan Gilbert <dgilbert@redhat.com> Tue Jan 24 18:00:30 2017 +0000
tree ecbc1e1fd3a3052910eff44f0f6e8a84b626b199
parent a3a3d8c73889282eb696535f1b5345d88b4dc58c

migration: disallow migrate_add_blocker during migration

If a migration is already in progress and somebody attempts
to add a migration blocker, this should rightly fail.

Add an errp parameter and a retcode return value to migrate_add_blocker.

Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com>
Message-Id: <1484566314-3987-5-git-send-email-ashijeetacharya@gmail.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Acked-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
  Merged with recent 'Allow invtsc migration' change

block/qcow.c

diff --git a/block/qcow.c b/block/qcow.c
index 7540f43..fb738fc 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -104,6 +104,7 @@
     unsigned int len, i, shift;
     int ret;
     QCowHeader header;
+    Error *local_err = NULL;
 
     ret = bdrv_pread(bs->file, 0, &header, sizeof(header));
     if (ret < 0) {
@@ -252,7 +253,12 @@
     error_setg(&s->migration_blocker, "The qcow format used by node '%s' "
                "does not support live migration",
                bdrv_get_device_or_node_name(bs));
-    migrate_add_blocker(s->migration_blocker);
+    ret = migrate_add_blocker(s->migration_blocker, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        error_free(s->migration_blocker);
+        goto fail;
+    }
 
     qemu_co_mutex_init(&s->lock);
     return 0;