openstack
/
neutron
Code Issues Proposed changes

Avoid dhcp agent race condition on subnet and network delete 

Ensure that ports that are about to be deleted are 'selected
for update'. By doing so, we avoid a race condition between
subnet and network delete operations carried out by two
separate server instances.

A race caused by the dhcp agent deleting the DHCP port
(caused by a subnet-delete event notification) can
still occur and will be addressed in a subsequent patch.

delete_subnet's way to delete ports has been tweaked to
ensure that postgres db can handle the SELECT FOR UPDATE
correctly.

Partial-Bug:1197627

Change-Id: I5bd75a758395a2faeff9db35a03c42dfa8ae0eab
This commit is contained in:
armando-migliaccio 2013-09-13 11:26:18 -07:00 committed by Gerrit Code Review
parent f0bd2ddb40
commit 6a5b3f4dd6
1 changed files with 17 additions and 16 deletions
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33
neutron/db/db_base_plugin_v2.py
View File

@ -442,11 +442,10 @@ class NeutronDbPluginV2(neutron_plugin_base_v2.NeutronPluginBaseV2,
{'ip_address': ip_address,
'network_id': network_id,
'subnet_id': subnet_id})
alloc_qry = context.session.query(
models_v2.IPAllocation).with_lockmode('update')
alloc_qry.filter_by(network_id=network_id,
ip_address=ip_address,
subnet_id=subnet_id).delete()
context.session.query(models_v2.IPAllocation).filter_by(
network_id=network_id,
ip_address=ip_address,
subnet_id=subnet_id).delete()
@staticmethod
def _generate_ip(context, subnets):
@ -990,8 +989,10 @@ class NeutronDbPluginV2(neutron_plugin_base_v2.NeutronPluginBaseV2,
with context.session.begin(subtransactions=True):
network = self._get_network(context, id)
filter = {'network_id': [id]}
ports = self.get_ports(context, filters=filter)
filters = {'network_id': [id]}
# NOTE(armando-migliaccio): stick with base plugin
ports = self._get_ports_query(
context, filters=filters).with_lockmode('update')
# check if there are any tenant owned ports in-use
only_auto_del = all(p['device_owner'] in AUTO_DELETE_PORT_OWNERS
@ -1266,17 +1267,17 @@ class NeutronDbPluginV2(neutron_plugin_base_v2.NeutronPluginBaseV2,
subnet = self._get_subnet(context, id)
# Check if any tenant owned ports are using this subnet
allocated_qry = context.session.query(models_v2.IPAllocation)
allocated_qry = allocated_qry.options(orm.joinedload('ports'))
allocated = allocated_qry.filter_by(subnet_id=id)
only_auto_del = all(not a.port_id or
a.ports.device_owner in AUTO_DELETE_PORT_OWNERS
for a in allocated)
if not only_auto_del:
raise q_exc.SubnetInUse(subnet_id=id)
allocated_qry = allocated_qry.join(models_v2.Port)
allocated = allocated_qry.filter_by(
network_id=subnet.network_id).with_lockmode('update')
# remove network owned ports
allocated.delete()
for a in allocated:
if a.ports.device_owner in AUTO_DELETE_PORT_OWNERS:
NeutronDbPluginV2._delete_ip_allocation(
context, subnet.network_id, id, a.ip_address)
else:
raise q_exc.SubnetInUse(subnet_id=id)
context.session.delete(subnet)