diff --git a/swift_ceph_backend/rados_diskfile.py b/swift_ceph_backend/rados_diskfile.py
index c3656e5..f567c91 100644
--- a/swift_ceph_backend/rados_diskfile.py
+++ b/swift_ceph_backend/rados_diskfile.py
@@ -100,11 +100,12 @@ class RadosFileSystem(object):
 
         def write(self, obj, offset, data):
             try:
-                return self._ioctx.write(obj, data, offset)
+                self._ioctx.write(obj, data, offset)
             except self._fs.RADOS.NoSpace:
                 raise DiskFileNoSpace()
             except Exception:
                 raise DiskFileError()
+            return len(data)
 
         def read(self, obj, off):
             return self._ioctx.read(obj, offset=off)
@@ -163,6 +164,9 @@ class DiskFileWriter(object):
         metadata['name'] = self._name
         self._fs.put_object(self._name, metadata)
 
+    def commit(self, timestamp):
+        pass
+
 
 class DiskFileReader(object):
     """
diff --git a/swift_ceph_backend/rados_server.py b/swift_ceph_backend/rados_server.py
index 770d66d..a64b739 100644
--- a/swift_ceph_backend/rados_server.py
+++ b/swift_ceph_backend/rados_server.py
@@ -51,7 +51,8 @@ class ObjectController(server.ObjectController):
                                              container, obj, **kwargs)
 
     def async_update(self, op, account, container, obj, host, partition,
-                     contdevice, headers_out, objdevice):
+                     contdevice, headers_out, objdevice, policy,
+                     logger_thread_locals=None):
         """
         Sends or saves an async update.
 
@@ -66,7 +67,7 @@ class ObjectController(server.ObjectController):
                             request
         :param objdevice: device name that the object is in
         """
-        headers_out['user-agent'] = 'obj-server %s' % os.getpid()
+        headers_out['user-agent'] = 'object-server %s' % os.getpid()
         full_path = '/%s/%s/%s' % (account, container, obj)
         if all([host, partition, contdevice]):
             try:
diff --git a/tests/test_rados_diskfile.py b/tests/test_rados_diskfile.py
index 6194558..3d54b99 100644
--- a/tests/test_rados_diskfile.py
+++ b/tests/test_rados_diskfile.py
@@ -14,7 +14,7 @@
 # under the License.
 
 import mock
-from mock import call
+from mock import call, patch
 import cPickle as pickle
 import unittest
 from hashlib import md5
@@ -397,23 +397,24 @@ class TestRadosDiskFile(unittest.TestCase):
 
         writes = []
 
-        def ioctx_write(obj, data, offset):
+        def mock_write(self, obj, offset, data):
             writes.append((data, offset))
             return 2
 
-        self.ioctx.write = ioctx_write
-        with self.df.create() as writer:
-            assert(writer.write(fcont) == len(fcont))
+        with patch('swift_ceph_backend.rados_diskfile.'
+                   'RadosFileSystem._radosfs.write', mock_write):
+            with self.df.create() as writer:
+                assert(writer.write(fcont) == len(fcont))
 
-        check_list = [
-            (fcont, 0),
-            (fcont[2:], 2),
-            (fcont[4:], 4),
-            (fcont[6:], 6),
-            (fcont[8:], 8)]
-        assert(writes == check_list)
-        self._assert_if_rados_not_opened()
-        self._assert_if_rados_not_closed()
+            check_list = [
+                (fcont, 0),
+                (fcont[2:], 2),
+                (fcont[4:], 4),
+                (fcont[6:], 6),
+                (fcont[8:], 8)]
+            assert(writes == check_list)
+            self._assert_if_rados_not_opened()
+            self._assert_if_rados_not_closed()
 
     def test_df_writer_put(self):
         meta = {'Content-Length': 0,