commit 42cae28241cd0c213201d036bfbe13fb118e4bee
Author: Cyril Roelandt <[email protected]>
Date:   Mon Aug 18 17:45:35 2014 +0000

    libvirt: Make sure volumes are well detected during block migration
    
    Current implementation of live migration in libvirt incorrectly includes
    block devices on shared storage (e.g., NFS) when computing destination
    storage requirements. Since these volumes are already on shared storage
    they do not need to be migrated. As a result, migration fails if the
    amount of free space on the shared drive is less than the size of the
    volume to be migrated. The problem is addressed by adding a
    block_device_info parameter to check_can_live_migrate_source() to allow
    volumes to be filtered correctly when computing migration space
    requirements.
    
    This only fixes the issue on libvirt: it is unclear whether other
    implementations suffer from the same issue.
    
    Thanks to Florent Flament for spotting and fixing an issue while trying out
    this patch.
    
    Co-Authored-By: Florent Flament <[email protected]>
    Change-Id: Iac7d2cd2a70800fd89864463ca45c030c47411b0
    Closes-Bug: #1356552
    (cherry picked from commit 671aa9f8b7ca5274696f83bde0d4822ee431b837)

--- nova-2014.2.2/nova/compute/manager.py.~3~	2015-12-01 05:07:52.781465660 -0800
+++ nova-2014.2.2/nova/compute/manager.py	2015-12-01 05:07:52.795381628 -0800
@@ -4891,8 +4891,11 @@ class ComputeManager(manager.Manager):
         is_volume_backed = self.compute_api.is_volume_backed_instance(ctxt,
                                                                       instance)
         dest_check_data['is_volume_backed'] = is_volume_backed
+        block_device_info = self._get_instance_block_device_info(
+                            ctxt, instance, refresh_conn_info=True)
         return self.driver.check_can_live_migrate_source(ctxt, instance,
-                                                         dest_check_data)
+                                                         dest_check_data,
+                                                         block_device_info)
 
     @object_compat
     @wrap_exception()
--- nova-2014.2.2/nova/tests/compute/test_compute_mgr.py.~2~	2015-12-01 05:07:52.782691092 -0800
+++ nova-2014.2.2/nova/tests/compute/test_compute_mgr.py	2015-12-01 05:07:52.796520248 -0800
@@ -1302,13 +1302,19 @@ class ComputeManagerUnitTestCase(test.No
 
         self.mox.StubOutWithMock(self.compute.compute_api,
                                  'is_volume_backed_instance')
+        self.mox.StubOutWithMock(self.compute,
+                                 '_get_instance_block_device_info')
         self.mox.StubOutWithMock(self.compute.driver,
                                  'check_can_live_migrate_source')
 
         self.compute.compute_api.is_volume_backed_instance(
                 self.context, instance).AndReturn(is_volume_backed)
+        self.compute._get_instance_block_device_info(
+                self.context, instance, refresh_conn_info=True
+                ).AndReturn({'block_device_mapping': 'fake'})
         self.compute.driver.check_can_live_migrate_source(
-                self.context, instance, expected_dest_check_data)
+                self.context, instance, expected_dest_check_data,
+                {'block_device_mapping': 'fake'})
 
         self.mox.ReplayAll()
 
diff --git a/nova/tests/virt/libvirt/test_driver.py b/nova/tests/virt/libvirt/test_driver.py
index 613943b..c686b88 100644
--- a/nova/tests/virt/libvirt/test_driver.py
+++ b/nova/tests/virt/libvirt/test_driver.py
@@ -5323,7 +5323,7 @@ class LibvirtConnTestCase(test.TestCase):
         self.mox.StubOutWithMock(conn, "_assert_dest_node_has_enough_disk")
         conn._assert_dest_node_has_enough_disk(
             self.context, instance, dest_check_data['disk_available_mb'],
-            False)
+            False, None)
 
         self.mox.ReplayAll()
         ret = conn.check_can_live_migrate_source(self.context, instance,
@@ -5386,8 +5386,9 @@ class LibvirtConnTestCase(test.TestCase):
                 disk_available_mb=0)
 
         self.mox.StubOutWithMock(conn, "get_instance_disk_info")
-        conn.get_instance_disk_info(instance["name"]).AndReturn(
-                                            '[{"virt_disk_size":2}]')
+        conn.get_instance_disk_info(instance["name"],
+                                    block_device_info=None).AndReturn(
+                                        '[{"virt_disk_size":2}]')
 
         self.mox.ReplayAll()
         self.assertRaises(exception.MigrationError,
diff --git a/nova/virt/driver.py b/nova/virt/driver.py
index fd483e5..20f4dd1 100644
--- a/nova/virt/driver.py
+++ b/nova/virt/driver.py
@@ -808,7 +808,7 @@ class ComputeDriver(object):
         raise NotImplementedError()
 
     def check_can_live_migrate_source(self, context, instance,
-                                      dest_check_data):
+                                      dest_check_data, block_device_info=None):
         """Check if it is possible to execute live migration.
 
         This checks if the live migration can succeed, based on the
@@ -817,6 +817,7 @@ class ComputeDriver(object):
         :param context: security context
         :param instance: nova.db.sqlalchemy.models.Instance
         :param dest_check_data: result of check_can_live_migrate_destination
+        :param block_device_info: result of _get_instance_block_device_info
         :returns: a dict containing migration info (hypervisor-dependent)
         """
         raise NotImplementedError()
diff --git a/nova/virt/fake.py b/nova/virt/fake.py
index 049c519..fe9ff1c 100644
--- a/nova/virt/fake.py
+++ b/nova/virt/fake.py
@@ -426,7 +426,7 @@ class FakeDriver(driver.ComputeDriver):
         return {}
 
     def check_can_live_migrate_source(self, ctxt, instance_ref,
-                                      dest_check_data):
+                                      dest_check_data, block_device_info=None):
         return
 
     def finish_migration(self, context, migration, instance, disk_info,
diff --git a/nova/virt/hyperv/driver.py b/nova/virt/hyperv/driver.py
index 485aa23..fa42130 100644
--- a/nova/virt/hyperv/driver.py
+++ b/nova/virt/hyperv/driver.py
@@ -169,7 +169,7 @@ class HyperVDriver(driver.ComputeDriver):
             context, dest_check_data)
 
     def check_can_live_migrate_source(self, context, instance,
-                                      dest_check_data):
+                                      dest_check_data, block_device_info=None):
         return self._livemigrationops.check_can_live_migrate_source(
             context, instance, dest_check_data)
 
diff --git a/nova/virt/libvirt/driver.py b/nova/virt/libvirt/driver.py
index cec2013..d420f15 100644
--- a/nova/virt/libvirt/driver.py
+++ b/nova/virt/libvirt/driver.py
@@ -5028,7 +5028,8 @@ class LibvirtDriver(driver.ComputeDriver):
         self._cleanup_shared_storage_test_file(filename)
 
     def check_can_live_migrate_source(self, context, instance,
-                                      dest_check_data):
+                                      dest_check_data,
+                                      block_device_info=None):
         """Check if it is possible to execute live migration.
 
         This checks if the live migration can succeed, based on the
@@ -5037,6 +5038,7 @@ class LibvirtDriver(driver.ComputeDriver):
         :param context: security context
         :param instance: nova.db.sqlalchemy.models.Instance
         :param dest_check_data: result of check_can_live_migrate_destination
+        :param block_device_info: result of _get_instance_block_device_info
         :returns: a dict containing migration info
         """
         # Checking shared storage connectivity
@@ -5058,7 +5060,8 @@ class LibvirtDriver(driver.ComputeDriver):
                 raise exception.InvalidLocalStorage(reason=reason, path=source)
             self._assert_dest_node_has_enough_disk(context, instance,
                                     dest_check_data['disk_available_mb'],
-                                    dest_check_data['disk_over_commit'])
+                                    dest_check_data['disk_over_commit'],
+                                    block_device_info)
 
         elif not (dest_check_data['is_shared_block_storage'] or
                   dest_check_data['is_shared_instance_path']):
@@ -5106,7 +5109,8 @@ class LibvirtDriver(driver.ComputeDriver):
         return False
 
     def _assert_dest_node_has_enough_disk(self, context, instance,
-                                             available_mb, disk_over_commit):
+                                             available_mb, disk_over_commit,
+                                             block_device_info=None):
         """Checks if destination has enough disk for block migration."""
         # Libvirt supports qcow2 disk format,which is usually compressed
         # on compute nodes.
@@ -5122,7 +5126,8 @@ class LibvirtDriver(driver.ComputeDriver):
         if available_mb:
             available = available_mb * units.Mi
 
-        ret = self.get_instance_disk_info(instance['name'])
+        ret = self.get_instance_disk_info(instance['name'],
+                                          block_device_info=block_device_info)
         disk_infos = jsonutils.loads(ret)
 
         necessary = 0
--- nova-2014.2.2/nova/virt/xenapi/driver.py.~2~	2015-12-01 05:16:19.562306358 -0800
+++ nova-2014.2.2/nova/virt/xenapi/driver.py	2015-12-01 05:16:19.614403555 -0800
@@ -501,7 +501,7 @@ class XenAPIDriver(driver.ComputeDriver)
         pass
 
     def check_can_live_migrate_source(self, context, instance,
-                                      dest_check_data):
+                                      dest_check_data, block_device_info=None):
         """Check if it is possible to execute live migration.
 
         This checks if the live migration can succeed, based on the
@@ -511,6 +511,7 @@ class XenAPIDriver(driver.ComputeDriver)
         :param instance: nova.db.sqlalchemy.models.Instance
         :param dest_check_data: result of check_can_live_migrate_destination
                                 includes the block_migration flag
+        :param block_device_info: result of _get_instance_block_device_info
         """
         return self._vmops.check_can_live_migrate_source(context, instance,
                                                          dest_check_data)