---
features:
  - |
    Added a new configuration option ``image_conversion_disable`` to disallow
    conversion between image disk format and volume format when doing
    certain operations. This can prevent performance problems on a
    cinder-volume node due to the large amount of system resources
    consumed during image conversion. The default value is ``False``,
    which corresponds to Cinder's current behavior to always attempt
    image conversion.

    This option affects three Block Storage API calls:

    * Upload volume to image:
      ``POST /v3/volumes/{volume_id}/action`` with the
      ``os-volume_upload_image`` action.  This call will result in a
      400 (Bad Request) response when an image ``disk_format``
      that would require conversion is requested.
    * Create a volume:
      ``POST /v3/volumes`` with an ``imageRef`` attribute in the request
      body.  This will result in a 202 (Accepted) response, but if the
      image's ``disk_format`` would require conversion to be written to
      the volume, the volume will go to ``error`` status.
    * Reimage a volume:
      ``POST /v3/volumes/{volume_id}/action`` with the ``os-reimage``
      action.  This call will result in a 202 (Accepted) response, but
      if the image's ``disk_format`` would require conversion to be written
      to the volume, the volume will go to ``error`` status.

    In the latter two cases, an end user can determine what happened
    by using the `Messages API
    <https://docs.openstack.org/api-ref/block-storage/v3/#messages-messages>`_,
    which can be accessed using the `cinderclient
    <https://docs.openstack.org/python-cinderclient/latest/cli/details.html#cinder-message-list>`_
    or `openstackclient
    <https://docs.openstack.org/python-openstackclient/latest/cli/decoder.html>`_.