Storwize/SVC: Fix races in host-related functions

In the Storwize/SVC driver, initialize_connection checks if a host
object exists on the storage, and if not, creates one. Similarly,
terminate_connection checks if there are any more mappings for this
host, and deletes the host object if there are none. Consequently, there
exist races between two initialize_connection calls, two
terminate_connection calls, or one and one.

The easy solution here is to use locks. Because locks are files on the
local machine, this implies that all cinder-volume processes managing a
given Storwize/SVC contoller run on the same machine.

Change-Id: I62cd992e7150e7d16f1a2b2be6ef61c64b638858
Closes-Bug: #1274123

diff --git a/cinder/volume/drivers/ibm/storwize_svc/__init__.py b/cinder/volume/drivers/ibm/storwize_svc/__init__.py
index 399258f0aa3f099aabefb96971d58b29f6e78875..a6df1eced330dd55e294162718b5d2a21c601d6c 100644 (file)
--- a/cinder/volume/drivers/ibm/storwize_svc/__init__.py
+++ b/cinder/volume/drivers/ibm/storwize_svc/__init__.py
@@ -41,6 +41,7 @@ from cinder import exception
 from cinder.openstack.common import excutils
 from cinder.openstack.common import log as logging
 from cinder import units
+from cinder import utils
 from cinder.volume.drivers.ibm.storwize_svc import helpers as storwize_helpers
 from cinder.volume.drivers.san import san
 from cinder.volume import volume_types
@@ -109,9 +110,10 @@ class StorwizeSVCDriver(san.SanDriver):
           get_volume_stats, minor bug fixes
     1.2.0 - Added retype
     1.2.1 - Code refactor, improved exception handling
+    1.2.2 - Fix bug #1274123 (races in host-related functions)
     """
 
-    VERSION = "1.2.1"
+    VERSION = "1.2.2"
 
     def __init__(self, *args, **kwargs):
         super(StorwizeSVCDriver, self).__init__(*args, **kwargs)
@@ -260,6 +262,7 @@ class StorwizeSVCDriver(san.SanDriver):
         return self._helpers.get_vdisk_params(self.configuration, self._state,
                                               type_id, volume_type=volume_type)
 
+    @utils.synchronized('storwize-host', external=True)
     def initialize_connection(self, volume, connector):
         """Perform the necessary work so that an iSCSI/FC connection can
         be made.
@@ -390,6 +393,7 @@ class StorwizeSVCDriver(san.SanDriver):
 
         return {'driver_volume_type': type_str, 'data': properties, }
 
+    @utils.synchronized('storwize-host', external=True)
     def terminate_connection(self, volume, connector, **kwargs):
         """Cleanup after an iSCSI connection has been terminated.