1 files changed, 192 insertions, 0 deletions
diff --git a/src/mongo/db/serverless/serverless_operation_lock_registry.cpp b/src/mongo/db/serverless/serverless_operation_lock_registry.cpp
new file mode 100644
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--- /dev/null
+++ b/src/mongo/db/serverless/serverless_operation_lock_registry.cpp
@@ -0,0 +1,192 @@
+/**
+ *    Copyright (C) 2022-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.
+ */
+
+#include "mongo/db/serverless/serverless_operation_lock_registry.h"
+#include "mongo/db/persistent_task_store.h"
+#include "mongo/db/repl/tenant_migration_state_machine_gen.h"
+#include "mongo/db/serverless/shard_split_state_machine_gen.h"
+#include "mongo/logv2/log.h"
+
+#define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kTenantMigration
+
+// Failpoint that will cause recoverLocks to return early.
+MONGO_FAIL_POINT_DEFINE(skipRecoverServerlessOperationLock);
+namespace mongo {
+
+const ServiceContext::Decoration<ServerlessOperationLockRegistry>
+    ServerlessOperationLockRegistry::get =
+        ServiceContext::declareDecoration<ServerlessOperationLockRegistry>();
+
+void ServerlessOperationLockRegistry::acquireLock(
+    ServerlessOperationLockRegistry::LockType lockType, const UUID& operationId) {
+    stdx::lock_guard<Latch> lg(_mutex);
+
+    // Verify there is no serverless operation in progress or it is the same type as the one
+    // acquiring the lock.
+    uassert(ErrorCodes::ConflictingServerlessOperation,
+            "Conflicting serverless operation in progress",
+            !_activeLockType || _activeLockType.get() == lockType);
+    invariant(_activeOperations.find(operationId) == _activeOperations.end(),
+              "Cannot acquire the serverless lock twice for the same operationId.");
+    _activeLockType = lockType;
+
+    _activeOperations.emplace(operationId);
+
+    LOGV2(6531500,
+          "Acquired serverless operation lock",
+          "type"_attr = lockType,
+          "id"_attr = operationId);
+}
+
+void ServerlessOperationLockRegistry::releaseLock(
+    ServerlessOperationLockRegistry::LockType lockType, const UUID& operationId) {
+    stdx::lock_guard<Latch> lg(_mutex);
+
+    invariant(_activeLockType && *_activeLockType == lockType,
+              "Cannot release a serverless lock that is not owned by the given lock type.");
+
+    invariant(_activeOperations.find(operationId) != _activeOperations.end(),
+              "Cannot release a serverless lock if the given operationId does not own the lock.");
+    _activeOperations.erase(operationId);
+
+    if (_activeOperations.empty()) {
+        _activeLockType.reset();
+    }
+
+    LOGV2(6531501,
+          "Released serverless operation lock",
+          "type"_attr = lockType,
+          "id"_attr = operationId);
+}
+
+void ServerlessOperationLockRegistry::onDropStateCollection(LockType lockType) {
+    stdx::lock_guard<Latch> lg(_mutex);
+
+    if (!_activeLockType || *_activeLockType != lockType) {
+        return;
+    }
+
+    LOGV2(6531505,
+          "Released all serverless locks due to state collection drop",
+          "type"_attr = lockType);
+
+    _activeLockType.reset();
+    _activeOperations.clear();
+}
+
+void ServerlessOperationLockRegistry::clear() {
+    stdx::lock_guard<Latch> lg(_mutex);
+    LOGV2(6531504,
+          "Releasing ServerlessMutualExclusionRegistry lock on shutdown",
+          "ns"_attr = _activeLockType);
+
+    _activeOperations.clear();
+    _activeLockType.reset();
+}
+
+void ServerlessOperationLockRegistry::recoverLocks(OperationContext* opCtx) {
+    if (skipRecoverServerlessOperationLock.shouldFail()) {
+        return;
+    }
+
+    auto& registry = ServerlessOperationLockRegistry::get(opCtx->getServiceContext());
+    registry.clear();
+
+    PersistentTaskStore<TenantMigrationDonorDocument> donorStore(
+        NamespaceString::kTenantMigrationDonorsNamespace);
+    donorStore.forEach(opCtx, {}, [&](const TenantMigrationDonorDocument& doc) {
+        // Do not acquire a lock for garbage-collectable documents
+        if (doc.getExpireAt()) {
+            return true;
+        }
+
+        registry.acquireLock(ServerlessOperationLockRegistry::LockType::kTenantDonor, doc.getId());
+
+        return true;
+    });
+
+    PersistentTaskStore<TenantMigrationRecipientDocument> recipientStore(
+        NamespaceString::kTenantMigrationRecipientsNamespace);
+    recipientStore.forEach(opCtx, {}, [&](const TenantMigrationRecipientDocument& doc) {
+        // Do not acquire a lock for garbage-collectable documents
+        if (doc.getExpireAt()) {
+            return true;
+        }
+
+        registry.acquireLock(ServerlessOperationLockRegistry::LockType::kTenantRecipient,
+                             doc.getId());
+
+        return true;
+    });
+
+    PersistentTaskStore<ShardSplitDonorDocument> splitStore(
+        NamespaceString::kShardSplitDonorsNamespace);
+    splitStore.forEach(opCtx, {}, [&](const ShardSplitDonorDocument& doc) {
+        // Do not acquire a lock for garbage-collectable documents
+        if (doc.getExpireAt()) {
+            return true;
+        }
+
+        registry.acquireLock(ServerlessOperationLockRegistry::LockType::kShardSplit, doc.getId());
+
+        return true;
+    });
+}
+
+const std::string kOperationLockFieldName = "operationLock";
+void ServerlessOperationLockRegistry::appendInfoForServerStatus(BSONObjBuilder* builder) const {
+    stdx::lock_guard<Latch> lg(_mutex);
+
+    if (!_activeLockType) {
+        builder->appendNull(kOperationLockFieldName);
+        return;
+    }
+
+    switch (_activeLockType.value()) {
+        case ServerlessOperationLockRegistry::LockType::kShardSplit:
+            builder->append(kOperationLockFieldName, "shard split donor");
+            break;
+        case ServerlessOperationLockRegistry::LockType::kTenantDonor:
+            builder->append(kOperationLockFieldName, "tenant migration donor");
+            break;
+        case ServerlessOperationLockRegistry::LockType::kTenantRecipient:
+            builder->append(kOperationLockFieldName, "tenant migration recipient");
+            break;
+    }
+}
+
+boost::optional<ServerlessOperationLockRegistry::LockType>
+ServerlessOperationLockRegistry::getActiveOperationType_forTest() {
+    stdx::lock_guard<Latch> lg(_mutex);
+
+    return _activeLockType;
+}
+
+
+}  // namespace mongo