DRYing up volume_in_mapping code.

Libvirt, VMWare, and Xen drivers all reimplement this method. This
refactors the code into the `block_device` module so all drivers can
share it.

Future Work: Refactor xen so that strip_prefix doesn't need to be passed
to `volume_in_mapping`.

Change-Id: I026b655f2eb7ea9cebe84058749c05ce93bcb7d4

1 files changed, 25 insertions, 0 deletions

diff --git a/nova/block_device.py b/nova/block_device.py
index c95961911..1805ff15f 100644
--- a/nova/block_device.py
+++ b/nova/block_device.py
@@ -17,8 +17,11 @@
 
 import re
 
+from nova.openstack.common import log as logging
 from nova.virt import driver
 
+LOG = logging.getLogger(__name__)
+
 DEFAULT_ROOT_DEV_NAME = '/dev/sda1'
 _DEFAULT_MAPPINGS = {'ami': 'sda1',
                      'ephemeral0': 'sda2',
@@ -144,3 +147,25 @@ def match_device(device):
     if not match:
         return None
     return match.groups()
+
+
+def volume_in_mapping(mount_device, block_device_info, strip=strip_dev):
+    # FIXME(sirp): xen uses strip_prefix to be mountpoint agnostic. There is
+    # probably a better way to handle this so that strip_dev can be used
+    # exclusively.
+    block_device_list = [strip(vol['mount_device'])
+                         for vol in
+                         driver.block_device_info_get_mapping(
+                         block_device_info)]
+
+    swap = driver.block_device_info_get_swap(block_device_info)
+    if driver.swap_is_usable(swap):
+        block_device_list.append(strip(swap['device_name']))
+
+    block_device_list += [strip(ephemeral['device_name'])
+                          for ephemeral in
+                          driver.block_device_info_get_ephemerals(
+                          block_device_info)]
+
+    LOG.debug(_("block_device_list %s"), block_device_list)
+    return strip(mount_device) in block_device_list