SERVER-26155 Use read concern 'local' for dist lock manager on the config server

5 files changed, 39 insertions, 25 deletions

diff --git a/src/mongo/s/catalog/replset/dist_lock_catalog_impl.cpp b/src/mongo/s/catalog/replset/dist_lock_catalog_impl.cpp
index 376cd853954..5041cb119f0 100644
--- a/src/mongo/s/catalog/replset/dist_lock_catalog_impl.cpp
+++ b/src/mongo/s/catalog/replset/dist_lock_catalog_impl.cpp
@@ -62,8 +62,6 @@ namespace {
 const char kFindAndModifyResponseResultDocField[] = "value";
 const char kLocalTimeField[] = "localTime";
 
-const ReadPreferenceSetting kReadPref(ReadPreference::PrimaryOnly, TagSet());
-
 /**
  * Returns the resulting new object from the findAndModify response object.
  * Returns LockStateChangeFailed if value field was null, which indicates that
@@ -129,15 +127,18 @@ StatusWith<OID> extractElectionId(const BSONObj& responseObj) {
 
 }  // unnamed namespace
 
-DistLockCatalogImpl::DistLockCatalogImpl(ShardRegistry* shardRegistry)
-    : _client(shardRegistry), _lockPingNS(LockpingsType::ConfigNS), _locksNS(LocksType::ConfigNS) {}
+DistLockCatalogImpl::DistLockCatalogImpl(ShardRegistry* shardRegistry, bool isLocal)
+    : _client(shardRegistry),
+      _isLocal(isLocal),
+      _lockPingNS(LockpingsType::ConfigNS),
+      _locksNS(LocksType::ConfigNS) {}
 
 DistLockCatalogImpl::~DistLockCatalogImpl() = default;
 
 StatusWith<LockpingsType> DistLockCatalogImpl::getPing(OperationContext* txn,
                                                        StringData processID) {
-    auto findResult = _findOnConfig(
-        txn, kReadPref, _lockPingNS, BSON(LockpingsType::process() << processID), BSONObj(), 1);
+    auto findResult =
+        _findOnConfig(txn, _lockPingNS, BSON(LockpingsType::process() << processID), BSONObj(), 1);
 
     if (!findResult.isOK()) {
         return findResult.getStatus();
@@ -376,7 +377,7 @@ Status DistLockCatalogImpl::unlockAll(OperationContext* txn, const std::string&
 StatusWith<DistLockCatalog::ServerInfo> DistLockCatalogImpl::getServerInfo(OperationContext* txn) {
     auto resultStatus = _client->getConfigShard()->runCommandWithFixedRetryAttempts(
         txn,
-        kReadPref,
+        ReadPreferenceSetting{ReadPreference::PrimaryOnly},
         "admin",
         BSON("serverStatus" << 1),
         Shard::kDefaultConfigCommandTimeout,
@@ -410,8 +411,8 @@ StatusWith<DistLockCatalog::ServerInfo> DistLockCatalogImpl::getServerInfo(Opera
 
 StatusWith<LocksType> DistLockCatalogImpl::getLockByTS(OperationContext* txn,
                                                        const OID& lockSessionID) {
-    auto findResult = _findOnConfig(
-        txn, kReadPref, _locksNS, BSON(LocksType::lockID(lockSessionID)), BSONObj(), 1);
+    auto findResult =
+        _findOnConfig(txn, _locksNS, BSON(LocksType::lockID(lockSessionID)), BSONObj(), 1);
 
     if (!findResult.isOK()) {
         return findResult.getStatus();
@@ -436,8 +437,7 @@ StatusWith<LocksType> DistLockCatalogImpl::getLockByTS(OperationContext* txn,
 }
 
 StatusWith<LocksType> DistLockCatalogImpl::getLockByName(OperationContext* txn, StringData name) {
-    auto findResult =
-        _findOnConfig(txn, kReadPref, _locksNS, BSON(LocksType::name() << name), BSONObj(), 1);
+    auto findResult = _findOnConfig(txn, _locksNS, BSON(LocksType::name() << name), BSONObj(), 1);
 
     if (!findResult.isOK()) {
         return findResult.getStatus();
@@ -478,15 +478,20 @@ Status DistLockCatalogImpl::stopPing(OperationContext* txn, StringData processId
     return findAndModifyStatus.getStatus();
 }
 
-StatusWith<vector<BSONObj>> DistLockCatalogImpl::_findOnConfig(
-    OperationContext* txn,
-    const ReadPreferenceSetting& readPref,
-    const NamespaceString& nss,
-    const BSONObj& query,
-    const BSONObj& sort,
-    boost::optional<long long> limit) {
+StatusWith<vector<BSONObj>> DistLockCatalogImpl::_findOnConfig(OperationContext* txn,
+                                                               const NamespaceString& nss,
+                                                               const BSONObj& query,
+                                                               const BSONObj& sort,
+                                                               boost::optional<long long> limit) {
     auto result = _client->getConfigShard()->exhaustiveFindOnConfig(
-        txn, readPref, repl::ReadConcernLevel::kMajorityReadConcern, nss, query, sort, limit);
+        txn,
+        ReadPreferenceSetting{ReadPreference::PrimaryOnly},
+        (_isLocal ? repl::ReadConcernLevel::kLocalReadConcern
+                  : repl::ReadConcernLevel::kMajorityReadConcern),
+        nss,
+        query,
+        sort,
+        limit);
     if (!result.isOK()) {
         return result.getStatus();
     }
diff --git a/src/mongo/s/catalog/replset/dist_lock_catalog_impl.h b/src/mongo/s/catalog/replset/dist_lock_catalog_impl.h
index 6f26a3a1235..8903eb5b33a 100644
--- a/src/mongo/s/catalog/replset/dist_lock_catalog_impl.h
+++ b/src/mongo/s/catalog/replset/dist_lock_catalog_impl.h
@@ -48,7 +48,12 @@ struct ReadPreferenceSetting;
 
 class DistLockCatalogImpl final : public DistLockCatalog {
 public:
-    DistLockCatalogImpl(ShardRegistry* shardRegistry);
+    /**
+     * Constructs a new dist lock catalog, specifying whether it is being used locally on the config
+     * server or remotely (from a shard or mongos). See the comment for the associated class
+     * variable for more information.
+     */
+    DistLockCatalogImpl(ShardRegistry* shardRegistry, bool isLocal);
 
     virtual ~DistLockCatalogImpl();
 
@@ -95,13 +100,16 @@ private:
     Status _unlock(OperationContext* txn, const FindAndModifyRequest& request);
 
     StatusWith<std::vector<BSONObj>> _findOnConfig(OperationContext* txn,
-                                                   const ReadPreferenceSetting& readPref,
                                                    const NamespaceString& nss,
                                                    const BSONObj& query,
                                                    const BSONObj& sort,
                                                    boost::optional<long long> limit);
 
-    ShardRegistry* _client;
+    ShardRegistry* const _client;
+
+    // Indicates whether this catalog manager is used as a local or remote instance. Controls the
+    // read concern level used for dist lock information lookup.
+    const bool _isLocal;
 
     // These are not static to avoid initialization order fiasco.
     const NamespaceString _lockPingNS;
diff --git a/src/mongo/s/catalog/replset/dist_lock_catalog_impl_test.cpp b/src/mongo/s/catalog/replset/dist_lock_catalog_impl_test.cpp
index 99a7d61de8d..1588b0d4c30 100644
--- a/src/mongo/s/catalog/replset/dist_lock_catalog_impl_test.cpp
+++ b/src/mongo/s/catalog/replset/dist_lock_catalog_impl_test.cpp
@@ -97,7 +97,7 @@ protected:
 
     std::unique_ptr<DistLockCatalog> makeDistLockCatalog(ShardRegistry* shardRegistry) override {
         invariant(shardRegistry);
-        return stdx::make_unique<DistLockCatalogImpl>(shardRegistry);
+        return stdx::make_unique<DistLockCatalogImpl>(shardRegistry, false);
     }
 
     std::unique_ptr<DistLockManager> makeDistLockManager(
diff --git a/src/mongo/s/config_server_test_fixture.cpp b/src/mongo/s/config_server_test_fixture.cpp
index f648eb14721..40253df784e 100644
--- a/src/mongo/s/config_server_test_fixture.cpp
+++ b/src/mongo/s/config_server_test_fixture.cpp
@@ -108,7 +108,7 @@ void ConfigServerTestFixture::setUp() {
 std::unique_ptr<DistLockCatalog> ConfigServerTestFixture::makeDistLockCatalog(
     ShardRegistry* shardRegistry) {
     invariant(shardRegistry);
-    return stdx::make_unique<DistLockCatalogImpl>(shardRegistry);
+    return stdx::make_unique<DistLockCatalogImpl>(shardRegistry, false);
 }
 
 std::unique_ptr<DistLockManager> ConfigServerTestFixture::makeDistLockManager(
diff --git a/src/mongo/s/sharding_initialization.cpp b/src/mongo/s/sharding_initialization.cpp
index 0c46df7a3cd..5ae5edf9593 100644
--- a/src/mongo/s/sharding_initialization.cpp
+++ b/src/mongo/s/sharding_initialization.cpp
@@ -84,7 +84,8 @@ std::unique_ptr<ThreadPoolTaskExecutor> makeTaskExecutor(std::unique_ptr<Network
 std::unique_ptr<ShardingCatalogClient> makeCatalogClient(ServiceContext* service,
                                                          ShardRegistry* shardRegistry,
                                                          StringData distLockProcessId) {
-    auto distLockCatalog = stdx::make_unique<DistLockCatalogImpl>(shardRegistry);
+    auto distLockCatalog = stdx::make_unique<DistLockCatalogImpl>(
+        shardRegistry, serverGlobalParams.clusterRole == ClusterRole::ConfigServer);
     auto distLockManager =
         stdx::make_unique<ReplSetDistLockManager>(service,
                                                   distLockProcessId,