iotests/262: Switch source/dest VM launch order

Launching the destination VM before the source VM gives us a regression
test for HEAD^:

The guest device causes a read from the disk image through
guess_disk_lchs().  This will not work if the first sector (containing
the partition table) is yet unallocated, we use COR, and the node is
inactive.

By launching the source VM before the destination, however, the COR
filter on the source will allocate that area in the image shared between
both VMs, thus the problem will not become apparent.

Switching the launch order causes the sector to still be unallocated
when guess_disk_lchs() runs on the inactive node in the destination VM,
and thus we get our test case.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20191001174827.11081-3-mreitz@redhat.com
Message-Id: <20191001174827.11081-3-mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

diff --git a/tests/qemu-iotests/262 b/tests/qemu-iotests/262
index 398f63587e7ab7ea6c25010ea6b451cb89c0cea0..0963daa806625673aa4a72bd6a6669c2eaaddc67 100755 (executable)
--- a/tests/qemu-iotests/262
+++ b/tests/qemu-iotests/262
@@ -54,12 +54,6 @@ with iotests.FilePath('img') as img_path, \
 
     os.mkfifo(fifo)
 
-    iotests.log('Launching source VM...')
-    add_opts(vm_a)
-    vm_a.launch()
-
-    vm_a.enable_migration_events('A')
-
     iotests.log('Launching destination VM...')
     add_opts(vm_b)
     vm_b.add_incoming("exec: cat '%s'" % (fifo))
@@ -67,6 +61,12 @@ with iotests.FilePath('img') as img_path, \
 
     vm_b.enable_migration_events('B')
 
+    iotests.log('Launching source VM...')
+    add_opts(vm_a)
+    vm_a.launch()
+
+    vm_a.enable_migration_events('A')
+
     iotests.log('Starting migration to B...')
     iotests.log(vm_a.qmp('migrate', uri='exec:cat >%s' % (fifo)))
     with iotests.Timeout(3, 'Migration does not complete'):

diff --git a/tests/qemu-iotests/262.out b/tests/qemu-iotests/262.out
index 5a58e5e9f8a357b70ffe61b7e533aa4b8b111abd..8e04c496c40a1ee8b9d7f1cf576a8d6ded726643 100644 (file)
--- a/tests/qemu-iotests/262.out
+++ b/tests/qemu-iotests/262.out
@@ -1,9 +1,9 @@
-Launching source VM...
-Enabling migration QMP events on A...
-{"return": {}}
 Launching destination VM...
 Enabling migration QMP events on B...
 {"return": {}}
+Launching source VM...
+Enabling migration QMP events on A...
+{"return": {}}
 Starting migration to B...
 {"return": {}}
 {"data": {"status": "setup"}, "event": "MIGRATION", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}}