Add a convenience function to osd_client to send Ceph OSD
'class' ops. The interface assumes that the request and
reply data each consist of single pages.
Signed-off-by: NDouglas Fuller <dfuller@redhat.com>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>
Reviewed-by: NMike Christie <mchristi@redhat.com>
Reviewed-by: NAlex Elder <elder@linaro.org>