Comment 13 for bug 1900775

I tested Corey's fix (via ppa) side-by-side with a cinder unit with version 2:15.4.0-0ubuntu1~cloud0 (from bionic-proposed/train).

I used a bionic qcow2 image with:
  openstack volume create --image bionic --size 3 --type stable2-az2 vernvol

Again, glance is backended by the az1 ceph cluster so this is a cross-cluster copy. In our previous tests, qcow2 images tend to fail at a much higher rate than raw images.

On the unpatched cinder, 77% failure with 23 out of 30 tries erring with:
  Exception during message handling: cinder.exception.ImageCopyFailure: Failed to copy image to volume: deleting volume volume-1b4d5231-2baf-4880-a380-f1dc937b20bd that has snapshot

On Corey's patched version, 0% failure. 30 out of 30 volumes succeeded.

So, in this deployment, this simple retry solves the problem.