SERVER-55867 commitMovePrimary concurrent with setFCV may write incorrect metadata

3 files changed, 27 insertions, 9 deletions

diff --git a/src/mongo/db/s/config/sharding_catalog_manager.cpp b/src/mongo/db/s/config/sharding_catalog_manager.cpp
index 0d96ec927f4..ce8ce68368b 100644
--- a/src/mongo/db/s/config/sharding_catalog_manager.cpp
+++ b/src/mongo/db/s/config/sharding_catalog_manager.cpp
@@ -314,7 +314,8 @@ ShardingCatalogManager::ShardingCatalogManager(
       _executorForAddShard(std::move(addShardExecutor)),
       _kShardMembershipLock("shardMembershipLock"),
       _kChunkOpLock("chunkOpLock"),
-      _kZoneOpLock("zoneOpLock") {
+      _kZoneOpLock("zoneOpLock"),
+      _kDatabaseOpLock("databaseOpLock") {
     startup();
 }
 
@@ -657,6 +658,7 @@ void ShardingCatalogManager::_upgradeDatabasesEntriesTo50(OperationContext* opCt
         auto now = VectorClock::get(opCtx)->getTime();
         auto clusterTime = now.clusterTime().asTimestamp();
 
+        Lock::ExclusiveLock lock(opCtx->lockState(), _kDatabaseOpLock);
         updateConfigDocumentDBDirect(
             opCtx,
             DatabaseType::ConfigNS,
@@ -690,14 +692,17 @@ void ShardingCatalogManager::_upgradeDatabasesEntriesTo50(OperationContext* opCt
 void ShardingCatalogManager::_downgradeDatabasesEntriesToPre50(OperationContext* opCtx) {
     LOGV2(5258806, "Starting downgrade of config.databases");
 
-    updateConfigDocumentDBDirect(
-        opCtx,
-        DatabaseType::ConfigNS,
-        {} /* query */,
-        BSON("$unset" << BSON(DatabaseType::version() + "." + DatabaseVersion::kTimestampFieldName
-                              << "")),
-        false /* upsert */,
-        true /* multi */);
+    {
+        Lock::ExclusiveLock lock(opCtx->lockState(), _kDatabaseOpLock);
+        updateConfigDocumentDBDirect(
+            opCtx,
+            DatabaseType::ConfigNS,
+            {} /* query */,
+            BSON("$unset" << BSON(
+                     DatabaseType::version() + "." + DatabaseVersion::kTimestampFieldName << "")),
+            false /* upsert */,
+            true /* multi */);
+    }
 
     auto const catalogCache = Grid::get(opCtx)->catalogCache();
     auto const configShard = Grid::get(opCtx)->shardRegistry()->getConfigShard();
diff --git a/src/mongo/db/s/config/sharding_catalog_manager.h b/src/mongo/db/s/config/sharding_catalog_manager.h
index 5a72d95d78a..e8a7da2b356 100644
--- a/src/mongo/db/s/config/sharding_catalog_manager.h
+++ b/src/mongo/db/s/config/sharding_catalog_manager.h
@@ -671,6 +671,16 @@ private:
      * taking this.
      */
     Lock::ResourceMutex _kZoneOpLock;
+
+    /**
+     * Lock for local database operations. This should be acquired when executing
+     * 'commitMovePrimary' and 'setFeatureCompatibilityVersion' commands which affect the
+     * config.databases collection. No other locks should be held when locking this. If an operation
+     * needs to take database locks (for example to write to a local collection) those locks should
+     * be taken after taking this.
+     * TODO (SERVER-53283): Remove once version 5.0 has been released.
+     */
+    Lock::ResourceMutex _kDatabaseOpLock;
 };
 
 }  // namespace mongo
diff --git a/src/mongo/db/s/config/sharding_catalog_manager_database_operations.cpp b/src/mongo/db/s/config/sharding_catalog_manager_database_operations.cpp
index 00d36d441d7..0f9450cf712 100644
--- a/src/mongo/db/s/config/sharding_catalog_manager_database_operations.cpp
+++ b/src/mongo/db/s/config/sharding_catalog_manager_database_operations.cpp
@@ -266,6 +266,9 @@ Status ShardingCatalogManager::commitMovePrimary(OperationContext* opCtx,
 
     auto const configShard = Grid::get(opCtx)->shardRegistry()->getConfigShard();
 
+    // TODO (SERVER-53283): Remove once version 5.0 has been released.
+    Lock::SharedLock lock(opCtx->lockState(), _kDatabaseOpLock);
+
     // Must use local read concern because we will perform subsequent writes.
     auto findResponse = uassertStatusOK(
         configShard->exhaustiveFindOnConfig(opCtx,