It also can reproduced with iSCSI protocol.  Following is the error logs:
ERROR nova.virt.block_device  Traceback (most recent call last):
 ERROR nova.virt.block_device    File "/opt/stack/new/nova/nova/virt/block_device.py", line 256, in attach
 ERROR nova.virt.block_device      device_type=self['device_type'], encryption=encryption)
 ERROR nova.virt.block_device    File "/opt/stack/new/nova/nova/virt/libvirt/driver.py", line 1099, in attach_volume
 ERROR nova.virt.block_device      self._connect_volume(connection_info, disk_info)
 ERROR nova.virt.block_device    File "/opt/stack/new/nova/nova/virt/libvirt/driver.py", line 1049, in _connect_volume
 ERROR nova.virt.block_device      driver.connect_volume(connection_info, disk_info)
 ERROR nova.virt.block_device    File "/opt/stack/new/nova/nova/virt/libvirt/volume/iscsi.py", line 84, in connect_volume
 ERROR nova.virt.block_device      device_info = self.connector.connect_volume(connection_info['data'])
 ERROR nova.virt.block_device    File "/usr/local/lib/python2.7/dist-packages/oslo_concurrency/lockutils.py", line 254, in inner
 ERROR nova.virt.block_device      return f(*args, **kwargs)
 ERROR nova.virt.block_device    File "/usr/local/lib/python2.7/dist-packages/os_brick/initiator/connector.py", line 499, in connect_volume
 ERROR nova.virt.block_device      raise exception.VolumeDeviceNotFound(device=host_devices)
 ERROR nova.virt.block_device  VolumeDeviceNotFound: Volume device not found at [u'/dev/disk/by-path/ip-9.11.101.17:3260-iscsi-iqn.1986-03.com.ibm:2145.arctbd3.arc64g00gf-2-lun-4'].
 ERROR nova.virt.block_device 
 ERROR nova.compute.manager [req-02370405-6fa4-414d-a588-39b84cf2caa0 tempest-TestEncryptedCinderVolumes-586258091 tempest-TestEncryptedCinderVolumes-19401]  Failed to attach b70c823c-7992-445a-8d24-5668fe762818 at /dev/vdb
 ERROR nova.compute.manager  Traceback (most recent call last):
 ERROR nova.compute.manager    File "/opt/stack/new/nova/nova/compute/manager.py", line 4536, in _attach_volume
 ERROR nova.compute.manager      do_check_attach=False, do_driver_attach=True)
 ERROR nova.compute.manager    File "/opt/stack/new/nova/nova/virt/block_device.py", line 52, in wrapped
 ERROR nova.compute.manager      ret_val = method(obj, context, *args, **kwargs)
 ERROR nova.compute.manager    File "/opt/stack/new/nova/nova/virt/block_device.py", line 265, in attach
 ERROR nova.compute.manager      connector)
 ERROR nova.compute.manager    File "/usr/local/lib/python2.7/dist-packages/oslo_utils/excutils.py", line 195, in __exit__
 ERROR nova.compute.manager      six.reraise(self.type_, self.value, self.tb)
 ERROR nova.compute.manager    File "/opt/stack/new/nova/nova/virt/block_device.py", line 256, in attach
 ERROR nova.compute.manager      device_type=self['device_type'], encryption=encryption)
 ERROR nova.compute.manager    File "/opt/stack/new/nova/nova/virt/libvirt/driver.py", line 1099, in attach_volume
 ERROR nova.compute.manager      self._connect_volume(connection_info, disk_info)
 ERROR nova.compute.manager    File "/opt/stack/new/nova/nova/virt/libvirt/driver.py", line 1049, in _connect_volume
 ERROR nova.compute.manager      driver.connect_volume(connection_info, disk_info)
 ERROR nova.compute.manager    File "/opt/stack/new/nova/nova/virt/libvirt/volume/iscsi.py", line 84, in connect_volume
 ERROR nova.compute.manager      device_info = self.connector.connect_volume(connection_info['data'])
 ERROR nova.compute.manager    File "/usr/local/lib/python2.7/dist-packages/oslo_concurrency/lockutils.py", line 254, in inner
 ERROR nova.compute.manager      return f(*args, **kwargs)
 ERROR nova.compute.manager    File "/usr/local/lib/python2.7/dist-packages/os_brick/initiator/connector.py", line 499, in connect_volume
 ERROR nova.compute.manager      raise exception.VolumeDeviceNotFound(device=host_devices)
 ERROR nova.compute.manager  VolumeDeviceNotFound: Volume device not found at [u'/dev/disk/by-path/ip-9.11.101.17:3260-iscsi-iqn.1986-03.com.ibm:2145.arctbd3.arc64g00gf-2-lun-4']