Quorum on durable response is too low

Increase the .durable quorum from 2 to "parity + 1" to guarantee
that we will never fail to rebuild an object.  Otherwise, with
low durable responses back (< parity + 1), the putter objects
return with failed attribute set to true, thereby failing the
rebuild of fragments for an object.

Change-Id: I80d666f61273e589d0990baa78fd657b3470785d
Closes-Bug: 1484565

swift/proxy/controllers/obj.py

@@ -2370,10 +2370,9 @@ class ECObjectController(BaseObjectController):
             need_quorum = False
             # The .durable file will propagate in a replicated fashion; if
             # one exists, the reconstructor will spread it around. Thus, we
-            # don't require as many .durable files to be successfully
-            # written as we do fragment archives in order to call the PUT a
-            # success.
-            min_conns = 2
+            # require "parity + 1" .durable files to be successfully written
+            # as we do fragment archives in order to call the PUT a success.
+            min_conns = policy.ec_nparity + 1
             putters = [p for p in putters if not p.failed]
             # ignore response etags, and quorum boolean
             statuses, reasons, bodies, _etags, _quorum = \

test/unit/proxy/controllers/test_obj.py

@@ -1479,7 +1479,7 @@ class TestECObjController(BaseObjectControllerMixin, unittest.TestCase):
         codes = [FakeStatus(201, response_sleep=response_sleep)
                  for i in range(self.replicas())]
         # swap out some with regular fast responses
-        number_of_fast_responses_needed_to_be_quick_enough = 2
+        number_of_fast_responses_needed_to_be_quick_enough = 5
         fast_indexes = random.sample(
             range(self.replicas()),
             number_of_fast_responses_needed_to_be_quick_enough)
@@ -1496,6 +1496,21 @@ class TestECObjController(BaseObjectControllerMixin, unittest.TestCase):
         self.assertEqual(resp.status_int, 201)
         self.assertTrue(response_time < response_sleep)
 
+    def test_PUT_with_less_durable_responses(self):
+        req = swift.common.swob.Request.blank('/v1/a/c/o', method='PUT',
+                                              body='')
+
+        codes = [201] * self.policy.ec_nparity
+        codes += [503] * (self.policy.ec_ndata - 1)
+        random.shuffle(codes)
+        expect_headers = {
+            'X-Obj-Metadata-Footer': 'yes',
+            'X-Obj-Multiphase-Commit': 'yes'
+        }
+        with set_http_connect(*codes, expect_headers=expect_headers):
+            resp = req.get_response(self.app)
+        self.assertEqual(resp.status_int, 503)
+
     def test_COPY_with_ranges(self):
         req = swift.common.swob.Request.blank(
             '/v1/a/c/o', method='COPY',