From f692f727236b7e3e97b657c048194870ddf88a47 Mon Sep 17 00:00:00 2001
From: Rick Harris <rconradharris@gmail.com>
Date: Mon, 20 May 2013 23:51:09 +0000
Subject: xenapi: Disable VDI size check when root_gb=0

Nova uses root_gb=0 to indicate that we should use the image as-is without
trying to resize the root disk. Currently the xenapi virt-driver doesn't
properly implement this behavior.

This patch gets us a step closer by disabling the VDI size check when
root_gb=0. We still need to ensure that the disk-resize code handle root_gb=0
as well.

References bug 1155113

Change-Id: If91963e079e197a1315c48b8643f3419b42b0b2c
---
 nova/tests/virt/xenapi/test_vm_utils.py | 49 +++++++++++++++++++++++++++++++++
 nova/virt/xenapi/vm_utils.py            | 23 ++++++++--------
 2 files changed, 60 insertions(+), 12 deletions(-)

diff --git a/nova/tests/virt/xenapi/test_vm_utils.py b/nova/tests/virt/xenapi/test_vm_utils.py
index 57f031a4c..4a7370dd9 100644
--- a/nova/tests/virt/xenapi/test_vm_utils.py
+++ b/nova/tests/virt/xenapi/test_vm_utils.py
@@ -20,6 +20,7 @@ import contextlib
 import fixtures
 import mox
 
+from nova.compute import flavors
 from nova import exception
 from nova import test
 from nova import utils
@@ -365,3 +366,51 @@ class ResizeHelpersTestCase(test.TestCase):
         self.mox.ReplayAll()
 
         vm_utils._resize_part_and_fs("fake", 0, 20, 30)
+
+
+class CheckVDISizeTestCase(test.TestCase):
+    def setUp(self):
+        super(CheckVDISizeTestCase, self).setUp()
+        self.context = 'fakecontext'
+        self.session = 'fakesession'
+        self.instance = dict(uuid='fakeinstance')
+        self.vdi_uuid = 'fakeuuid'
+
+    def test_not_too_large(self):
+        self.mox.StubOutWithMock(flavors, 'extract_instance_type')
+        flavors.extract_instance_type(self.instance).AndReturn(
+                dict(root_gb=1))
+
+        self.mox.StubOutWithMock(vm_utils, '_get_vdi_chain_size')
+        vm_utils._get_vdi_chain_size(self.session,
+                self.vdi_uuid).AndReturn(1073741824)
+
+        self.mox.ReplayAll()
+
+        vm_utils._check_vdi_size(self.context, self.session, self.instance,
+                self.vdi_uuid)
+
+    def test_too_large(self):
+        self.mox.StubOutWithMock(flavors, 'extract_instance_type')
+        flavors.extract_instance_type(self.instance).AndReturn(
+                dict(root_gb=1))
+
+        self.mox.StubOutWithMock(vm_utils, '_get_vdi_chain_size')
+        vm_utils._get_vdi_chain_size(self.session,
+                self.vdi_uuid).AndReturn(1073741825)
+
+        self.mox.ReplayAll()
+
+        self.assertRaises(exception.InstanceTypeDiskTooSmall,
+                vm_utils._check_vdi_size, self.context, self.session,
+                self.instance, self.vdi_uuid)
+
+    def test_zero_root_gb_disables_check(self):
+        self.mox.StubOutWithMock(flavors, 'extract_instance_type')
+        flavors.extract_instance_type(self.instance).AndReturn(
+                dict(root_gb=0))
+
+        self.mox.ReplayAll()
+
+        vm_utils._check_vdi_size(self.context, self.session, self.instance,
+                self.vdi_uuid)
diff --git a/nova/virt/xenapi/vm_utils.py b/nova/virt/xenapi/vm_utils.py
index 69a944b9b..fde075000 100644
--- a/nova/virt/xenapi/vm_utils.py
+++ b/nova/virt/xenapi/vm_utils.py
@@ -1192,21 +1192,20 @@ def _get_vdi_chain_size(session, vdi_uuid):
 
 
 def _check_vdi_size(context, session, instance, vdi_uuid):
-    size_bytes = _get_vdi_chain_size(session, vdi_uuid)
-
-    # FIXME(jk0): this was copied directly from compute.manager.py, let's
-    # refactor this to a common area
     instance_type = flavors.extract_instance_type(instance)
-    allowed_size_gb = instance_type['root_gb']
-    allowed_size_bytes = allowed_size_gb * 1024 * 1024 * 1024
+    allowed_size = instance_type['root_gb'] * (1024 ** 3)
+
+    if not allowed_size:
+        # root_gb=0 indicates that we're disabling size checks
+        return
 
-    LOG.debug(_("image_size_bytes=%(size_bytes)d, allowed_size_bytes="
-                "%(allowed_size_bytes)d"), locals(), instance=instance)
+    size = _get_vdi_chain_size(session, vdi_uuid)
+    if size > allowed_size:
+        LOG.error(_("Image size %(size)d exceeded instance_type "
+                    "allowed size %(allowed_size)d"),
+                  {'size': size, 'allowed_size': allowed_size},
+                  instance=instance)
 
-    if size_bytes > allowed_size_bytes:
-        LOG.info(_("Image size %(size_bytes)d exceeded instance_type "
-                   "allowed size %(allowed_size_bytes)d"),
-                 locals(), instance=instance)
         raise exception.InstanceTypeDiskTooSmall()
 
 
-- 
cgit