Replace builtin hash with MD5 to solve 32/64-bit issues.

It seems that Python's builtin hash returns different
values on 32-bit and 64-bit architectures, so it's
safer to use a well-defined hash like MD5.

bug 1050359

Change-Id: Ibb49f7b9028085d2aedaf05b94e1e1dcdf5e4cb4

nova/tests/test_nfs.py

@@ -109,8 +109,9 @@ def test_local_path(self):
         volume['provider_location'] = self.TEST_NFS_EXPORT1
         volume['name'] = 'volume-123'
 
-        self.assertEqual('/mnt/test/12118957640568004265/volume-123',
-                         drv.local_path(volume))
+        self.assertEqual(
+            '/mnt/test/2f4f60214cf43c595666dd815f0360a4/volume-123',
+            drv.local_path(volume))
 
     def test_mount_nfs_should_mount_correctly(self):
         """_mount_nfs common case usage"""
@@ -212,7 +213,7 @@ def test_get_hash_str(self):
         """_get_hash_str should calculation correct value"""
         drv = self._driver
 
-        self.assertEqual('12118957640568004265',
+        self.assertEqual('2f4f60214cf43c595666dd815f0360a4',
                          drv._get_hash_str(self.TEST_NFS_EXPORT1))
 
     def test_get_mount_point_for_share(self):
@@ -221,7 +222,7 @@ def test_get_mount_point_for_share(self):
 
         nfs.FLAGS.nfs_mount_point_base = self.TEST_MNT_POINT_BASE
 
-        self.assertEqual('/mnt/test/12118957640568004265',
+        self.assertEqual('/mnt/test/2f4f60214cf43c595666dd815f0360a4',
                          drv._get_mount_point_for_share(self.TEST_NFS_EXPORT1))
 
     def test_get_available_capacity_with_df(self):

nova/volume/nfs.py

@@ -15,8 +15,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import ctypes
 import errno
+import hashlib
 import os
 
 from nova import exception
@@ -290,4 +290,4 @@ def _path_exists(self, path):
 
     def _get_hash_str(self, base_str):
         """returns string that represents hash of base_str (in a hex format)"""
-        return str(ctypes.c_uint64(hash(base_str)).value)
+        return hashlib.md5(base_str).hexdigest()