In accept_transfer() workflow (https://github.com/openstack/cinder/blob/master/cinder/transfer/api.py#L193)
try:
# Transfer ownership of the volume now, must use an elevated
# context.
self.volume_api.accept_transfer(context,
vol_ref,
context.user_id,
context.project_id)
self.db.transfer_accept(context.elevated(),
transfer_id,
context.user_id,
context.project_id)
self.volume_api.accept_transfer() sends out a RPC request (cast) to volume manager and volume driver may do something in backend (e.g. modify account for the volume), but since it's a unblocking RPC cast, this call returns pretty fast and the volume record in DB will be updated. There can be cases where DB update finishes even before volume manager / driver does their job. Unfortunately some driver(s) relies on original DB record to do their stuff (SolidFire for example). Such situation will turn volume into inconsistent state (between backend and cinder DB) and become unusable.
We may either change accept_transfer() in volume RPC API from CAST to blocking CALL, or we can pass enough original volume state to volume manger so that they don't have to rely on unreliable DB state.
Fix proposed to branch: master
Review: https:/