Make sure we have enough .durable's for GETs

Increase the number of nodes from which we require a final successful
HTTP responses before we return success to the client on a write - to
the same number of nodes we'll require successful responses from to
service a client request for a read.

Change-Id: Ifd36790faa0a5d00ec79c23d1f96a332a0ca0f0b
Related-Bug: #1469094

swift/proxy/controllers/obj.py

@@ -2443,10 +2443,14 @@ class ECObjectController(BaseObjectController):
             final_phase = True
             need_quorum = False
             # The .durable file will propagate in a replicated fashion; if
-            # one exists, the reconstructor will spread it around. Thus, we
+            # one exists, the reconstructor will spread it around.
-            # require "parity + 1" .durable files to be successfully written
+            # In order to avoid successfully writing an object, but refusing
-            # as we do fragment archives in order to call the PUT a success.
+            # to serve it on a subsequent GET because don't have enough
-            min_conns = policy.ec_nparity + 1
+            # durable data fragments - we require the same number of durable
+            # writes as quorum fragment writes.  If object servers are in the
+            # future able to serve their non-durable fragment archives we may
+            # be able to reduce this quorum count if needed.
+            min_conns = policy.quorum
             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

@@ -2108,7 +2108,8 @@ 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 = 5
+        number_of_fast_responses_needed_to_be_quick_enough = \
+            self.policy.quorum
         fast_indexes = random.sample(
             range(self.replicas()),
             number_of_fast_responses_needed_to_be_quick_enough)
@@ -2125,12 +2126,29 @@ class TestECObjController(BaseObjectControllerMixin, unittest.TestCase):
         self.assertEqual(resp.status_int, 201)
         self.assertTrue(response_time < response_sleep)
 
+    def test_PUT_with_just_enough_durable_responses(self):
+        req = swift.common.swob.Request.blank('/v1/a/c/o', method='PUT',
+                                              body='')
+
+        codes = [201] * (self.policy.ec_ndata + 1)
+        codes += [503] * (self.policy.ec_nparity - 1)
+        self.assertEqual(len(codes), self.replicas())
+        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, 201)
+
     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 = [201] * (self.policy.ec_ndata)
-        codes += [503] * (self.policy.ec_ndata - 1)
+        codes += [503] * (self.policy.ec_nparity)
+        self.assertEqual(len(codes), self.replicas())
         random.shuffle(codes)
         expect_headers = {
             'X-Obj-Metadata-Footer': 'yes',