[PATCH v2 1/6] iotests: 194: wait migration completion on target too

["Alex Bennée" <alex.bennee@linaro.org>]

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

It is possible, that shutdown on target occurs earlier than migration
finish. In this case we crash in bdrv_release_dirty_bitmap_locked()
on assertion "assert(!bdrv_dirty_bitmap_busy(bitmap));" as we do have
busy bitmap, as bitmap migration is ongoing.

We'll fix bitmap migration to gracefully cancel on early shutdown soon.
Now let's fix iotest 194 to wait migration completion before shutdown.

Note that in this test dest_vm.shutdown() is called implicitly, as vms
used as context-providers, see __exit__() method of QEMUMachine class.

Actually, not waiting migration finish is a wrong thing, but the test
started to crash after commit ae00aa239847682
"iotests: 194: test also migration of dirty bitmap", which added dirty
bitmaps here. So, Fixes: tag won't hurt.

Fixes: ae00aa2398476824f0eca80461da215e7cdc1c3b
Reported-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Tested-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20200604083341.26978-1-vsementsov@virtuozzo.com>
---
 tests/qemu-iotests/194     | 10 ++++++++++
 tests/qemu-iotests/194.out |  5 +++++
 2 files changed, 15 insertions(+)

diff --git a/tests/qemu-iotests/194 b/tests/qemu-iotests/194
index 3fad7c6c1ab..6dc2bc94d7e 100755
--- a/tests/qemu-iotests/194
+++ b/tests/qemu-iotests/194
@@ -87,4 +87,14 @@ with iotests.FilePath('source.img') as source_img_path, \
             iotests.log(dest_vm.qmp('nbd-server-stop'))
             break
 
+    iotests.log('Wait migration completion on target...')
+    migr_events = (('MIGRATION', {'data': {'status': 'completed'}}),
+                   ('MIGRATION', {'data': {'status': 'failed'}}))
+    event = dest_vm.events_wait(migr_events)
+    iotests.log(event, filters=[iotests.filter_qmp_event])
+
+    iotests.log('Check bitmaps on source:')
     iotests.log(source_vm.qmp('query-block')['return'][0]['dirty-bitmaps'])
+
+    iotests.log('Check bitmaps on target:')
+    iotests.log(dest_vm.qmp('query-block')['return'][0]['dirty-bitmaps'])
diff --git a/tests/qemu-iotests/194.out b/tests/qemu-iotests/194.out
index dd60dcc14f1..f70cf7610e0 100644
--- a/tests/qemu-iotests/194.out
+++ b/tests/qemu-iotests/194.out
@@ -21,4 +21,9 @@ Gracefully ending the `drive-mirror` job on source...
 {"data": {"device": "mirror-job0", "len": 1073741824, "offset": 1073741824, "speed": 0, "type": "mirror"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
 Stopping the NBD server on destination...
 {"return": {}}
+Wait migration completion on target...
+{"data": {"status": "completed"}, "event": "MIGRATION", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}
+Check bitmaps on source:
+[{"busy": false, "count": 0, "granularity": 65536, "name": "bitmap0", "persistent": false, "recording": true, "status": "active"}]
+Check bitmaps on target:
 [{"busy": false, "count": 0, "granularity": 65536, "name": "bitmap0", "persistent": false, "recording": true, "status": "active"}]
-- 
2.20.1