---
fixes:
  - |
    An incorrect lock in the remotefs code, which is used for the NFS driver,
    and other similar drivers, resulted in concurrent clone volume operations
    failing.  create_cloned_volume now locks on the source volume id, meaning
    multiple clone operations from the same source volume are serialized.

    A lock in the volume manager flow generally prevents this on normal clone
    volume operations, but this clone method in the driver is called for
    operations such as cloning from the cinder image-volume cache or cloning
    from a cinder backend used as a glance store.