iotest 169 uses the 'new' module to add methods to a class.  This module
no longer exists in Python 3.  Instead, we can use a lambda.  Best of
all, this works in 2.7 just as well.
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NEduardo Habkost <ehabkost@redhat.com>
Reviewed-by: NCleber Rosa <crosa@redhat.com>
Message-Id: <20181022135307.14398-8-mreitz@redhat.com>
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>

Test that we can resume source vm after [failed] migration, and bitmaps
are ok.
Signed-off-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: NJohn Snow <jsnow@redhat.com>

Before previous patch, iotest 169 was actually broken for the case
test_persistent__not_migbitmap__offline_shared, while formally
passing.

After migration log of vm_b had message:

    qemu-system-x86_64: Could not reopen qcow2 layer: Bitmap already
    exists: bitmap0

which means that invalidation failed and bs->drv = NULL.

It was because we've loaded bitmap twice: on open and on invalidation.

Add code to 169, to catch such fails.
Signed-off-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: NJohn Snow <jsnow@redhat.com>

Signed-off-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: NJohn Snow <jsnow@redhat.com>
Signed-off-by: NJohn Snow <jsnow@redhat.com>

Improve and fix 169:
    - use MIGRATION events instead of RESUME
    - make a TODO: enable dirty-bitmaps capability for offline case
    - recreate vm_b without -incoming near test end

This (likely) fixes racy faults at least of the following types:

    - timeout on waiting for RESUME event
    - sha256 mismatch on line 136 (142 after this patch)
    - fail to self.vm_b.launch() on line 135 (141 now after this patch)

And surely fixes cat processes, left after test finish.
Signed-off-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20180411122606.367301-3-vsementsov@virtuozzo.com
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Signed-off-by: NMax Reitz <mreitz@redhat.com>

Shared migration for dirty bitmaps is fixed by previous patches,
so we can enable the test.
Signed-off-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20180320170521.32152-5-vsementsov@virtuozzo.com
Signed-off-by: NMax Reitz <mreitz@redhat.com>

The test starts two vms (vm_a, vm_b), create dirty bitmap in
the first one, do several writes to corresponding device and
then migrate vm_a to vm_b.
Signed-off-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20180313180320.339796-13-vsementsov@virtuozzo.com