If we're swapping from a multiattach volume that has more than one
read/write attachment, another server on the secondary attachment could
be writing to the volume which is not getting copied into the volume to
which we're swapping, so we could have data loss during the swap.
This change does volume read/write attachment counting for the volume
we're swapping from and if there is more than one read/write attachment
on the volume, the swap volume operation fails with a 400 BadRequest
error.
Conflicts:
nova/tests/unit/compute/test_compute_api.py
NOTE(mriedem): The conflict is due to Stein change
I7d5bddc0aa1833cda5f4bcebe5e03bdd447f641a changing the
decorators on the _test_snapshot_and_backup method.
Depends-On: https://review.openstack.org/573025/
Closes-Bug: #1775418
Change-Id: Icd7fcb87a09c35a13e4e14235feb30a289d22778
(cherry picked from commit 5a1d159d14)
(cherry picked from commit 9b21d1067a)
c19d602f9b