---
fixes:
  - |
    `Bug #2031897 <https://bugs.launchpad.net/cinder/+bug/2031897>`_: Fixed
    issues for volume backups with the Ceph driver where failures of the first
    process ("rbd export-diff") were not caught. Instead, only the return code
    of the second process ("rbd import-diff") was recognized.

    This change also preserves the stderr that was lost previously
    in order to ease debugging.