Merge lp:~ltrager/maas/lp1519397-1.9 into lp:maas/1.9

[Lee Trager]

Cherry pick from trunk for lp1519397: Don't check empty cache_set filesystem_groups when finding parent devices

[Lee Trager (ltrager)]

Reviewed in https://code.launchpad.net/~ltrager/maas/lp1519397

review: Approve

=== modified file 'src/maasserver/models/tests/test_virtualblockdevice.py'
--- src/maasserver/models/tests/test_virtualblockdevice.py	2015-11-18 18:14:30 +0000
+++ src/maasserver/models/tests/test_virtualblockdevice.py	2015-11-25 08:27:41 +0000
@@ -20,6 +20,7 @@
 
 from django.core.exceptions import ValidationError
 from maasserver.enum import FILESYSTEM_GROUP_TYPE
+from maasserver.models.blockdevice import MIN_BLOCK_DEVICE_SIZE
 from maasserver.models.virtualblockdevice import VirtualBlockDevice
 from maasserver.testing.factory import factory
 from maasserver.testing.orm import reload_object
@@ -173,3 +174,19 @@
         virtualblockdevice = node.virtualblockdevice_set.first()
         self.assertEqual(
             len(fs_group_disks), len(virtualblockdevice.get_parents()))
+
+    def test_get_parents_handles_cache_set(self):
+        # Regression test for lp1519397
+        node = factory.make_Node(with_boot_disk=False)
+        volume_group = factory.make_VolumeGroup(node=node)
+        name = factory.make_name()
+        vguuid = "%s" % uuid4()
+        size = random.randint(MIN_BLOCK_DEVICE_SIZE, volume_group.get_size())
+        logical_volume = volume_group.create_logical_volume(
+            name=name, uuid=vguuid, size=size)
+        logical_volume = reload_object(logical_volume)
+        sdb = factory.make_PhysicalBlockDevice(node=node)
+        factory.make_CacheSet(block_device=sdb, node=node)
+        self.assertItemsEqual(
+            [fs.block_device_id for fs in volume_group.filesystems.all()],
+            [parent.id for parent in logical_volume.get_parents()])
 
=== modified file 'src/maasserver/models/virtualblockdevice.py'
--- src/maasserver/models/virtualblockdevice.py	2015-11-18 18:14:30 +0000
+++ src/maasserver/models/virtualblockdevice.py	2015-11-25 08:27:41 +0000
@@ -149,6 +149,12 @@
             elif fs.cache_set is not None:
                 # A block device/partition can only have one cache_set
                 fs_group = fs.cache_set.filesystemgroup_set.first()
+                # bcache devices only show up in cache_set.filesystemgroup_set,
+                # not in fs.filesystem_group. However if only a cache_set has
+                # been created and not a bcache device
+                # cache_set.filesystemgroup_set will be empty.
+                if fs_group is None:
+                    return False
             else:
                 return False
             for virtual_device in fs_group.virtual_devices.all():