SERVER-51347 Allow writes on a collection string-matching '.system.resharding.' for Resharding

4 files changed, 100 insertions, 1 deletions

diff --git a/src/mongo/db/namespace_string.cpp b/src/mongo/db/namespace_string.cpp
index b884d0e8ff5..2f67bdc839e 100644
--- a/src/mongo/db/namespace_string.cpp
+++ b/src/mongo/db/namespace_string.cpp
@@ -126,6 +126,8 @@ bool NamespaceString::isLegalClientSystemNS() const {
             return true;
         if (coll() == kIndexBuildEntryNamespace.coll())
             return true;
+        if (coll().find(".system.resharding.") != std::string::npos)
+            return true;
     } else if (db() == kLocalDb) {
         if (coll() == kSystemReplSetNamespace.coll())
             return true;
@@ -140,7 +142,6 @@ bool NamespaceString::isLegalClientSystemNS() const {
     if (coll() == kSystemDotViewsCollectionName)
         return true;
     if (isTemporaryReshardingCollection()) {
-        // Permit integration testing on resharding collections.
         return true;
     }
 
diff --git a/src/mongo/db/ops/insert.cpp b/src/mongo/db/ops/insert.cpp
index fff03006b9f..9d60154f528 100644
--- a/src/mongo/db/ops/insert.cpp
+++ b/src/mongo/db/ops/insert.cpp
@@ -227,6 +227,10 @@ Status userAllowedCreateNS(const NamespaceString& ns) {
             return Status::OK();
         }
 
+        if (ns.isConfigDB() && ns.isLegalClientSystemNS()) {
+            return Status::OK();
+        }
+
         return Status(ErrorCodes::BadValue, str::stream() << "Invalid namespace: " << ns);
     }
 
diff --git a/src/mongo/db/s/SConscript b/src/mongo/db/s/SConscript
index dc225305801..bcd10878025 100644
--- a/src/mongo/db/s/SConscript
+++ b/src/mongo/db/s/SConscript
@@ -437,6 +437,7 @@ env.CppUnitTest(
         'migration_util_test.cpp',
         'namespace_metadata_change_notifications_test.cpp',
         'resharding/resharding_recipient_service_test.cpp',
+        'resharding_collection_test.cpp',
         'resharding_destined_recipient_test.cpp',
         'session_catalog_migration_destination_test.cpp',
         'session_catalog_migration_source_test.cpp',
diff --git a/src/mongo/db/s/resharding_collection_test.cpp b/src/mongo/db/s/resharding_collection_test.cpp
new file mode 100644
index 00000000000..4c0614868a7
--- /dev/null
+++ b/src/mongo/db/s/resharding_collection_test.cpp
@@ -0,0 +1,93 @@
+/**
+ *    Copyright (C) 2020-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the Server Side Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kTest
+
+#include "mongo/platform/basic.h"
+
+#include "mongo/db/dbdirectclient.h"
+#include "mongo/db/repl/repl_client_info.h"
+#include "mongo/db/repl/wait_for_majority_service.h"
+#include "mongo/db/s/shard_server_test_fixture.h"
+#include "mongo/db/write_concern.h"
+#include "mongo/rpc/get_status_from_command_result.h"
+#include "mongo/unittest/unittest.h"
+
+using namespace fmt::literals;
+
+namespace mongo {
+namespace {
+
+class SimpleClient {
+public:
+    SimpleClient(OperationContext* opCtx) : _client(opCtx), _opCtx(opCtx) {}
+
+    Status insert(const NamespaceString& nss, const BSONObj& doc) {
+        const auto commandResponse = _client.runCommand([&] {
+            write_ops::Insert insertOp(nss);
+            insertOp.setDocuments({doc});
+            return insertOp.serialize({});
+        }());
+
+        auto status = getStatusFromWriteCommandReply(commandResponse->getCommandReply());
+
+        WriteConcernResult ignoreResult;
+        auto latestOpTime = repl::ReplClientInfo::forClient(_opCtx->getClient()).getLastOp();
+        uassertStatusOK(
+            waitForWriteConcern(_opCtx, latestOpTime, kMajorityWriteConcern, &ignoreResult));
+
+        return status;
+    }
+
+private:
+    const WriteConcernOptions kMajorityWriteConcern{
+        WriteConcernOptions::kMajority,
+        WriteConcernOptions::SyncMode::UNSET,
+        WriteConcernOptions::kWriteConcernTimeoutSharding};
+
+    DBDirectClient _client;
+    OperationContext* _opCtx;
+};
+
+using ReshardingCollectionTest = ShardServerTestFixture;
+
+TEST_F(ReshardingCollectionTest, TestWritesToTempReshardingCollection) {
+    SimpleClient client(operationContext());
+    auto uuid = UUID::gen();
+
+    auto tempNss = NamespaceString{"{}.system.resharding.{}"_format("test", uuid.toString())};
+    ASSERT_OK(client.insert(tempNss, BSON("x" << 5)));
+
+    auto chunksNss = NamespaceString{
+        "config.cache.chunks.{}.system.resharding.{}"_format("test", uuid.toString())};
+    ASSERT_OK(client.insert(chunksNss, BSON("X" << 5)));
+}
+
+}  // namespace
+}  // namespace mongo
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