SERVER-39517 Only use Collection MODE_X for index creation and drop

3 files changed, 9 insertions, 23 deletions

diff --git a/src/mongo/db/catalog/drop_indexes.cpp b/src/mongo/db/catalog/drop_indexes.cpp
index 56143447308..ef6074eaaff 100644
--- a/src/mongo/db/catalog/drop_indexes.cpp
+++ b/src/mongo/db/catalog/drop_indexes.cpp
@@ -200,7 +200,7 @@ Status dropIndexes(OperationContext* opCtx,
                    const BSONObj& cmdObj,
                    BSONObjBuilder* result) {
     return writeConflictRetry(opCtx, "dropIndexes", nss.db(), [opCtx, &nss, &cmdObj, result] {
-        AutoGetDb autoDb(opCtx, nss.db(), MODE_X);
+        AutoGetCollection autoColl(opCtx, nss, MODE_IX, MODE_X);
 
         bool userInitiatedWritesAndNotPrimary = opCtx->writesAreReplicated() &&
             !repl::ReplicationCoordinator::get(opCtx)->canAcceptWritesFor(opCtx, nss);
@@ -215,9 +215,9 @@ Status dropIndexes(OperationContext* opCtx,
         }
 
         // If db/collection does not exist, short circuit and return.
-        Database* db = autoDb.getDb();
-        Collection* collection = db ? db->getCollection(opCtx, nss) : nullptr;
-        if (!db || !collection) {
+        Database* db = autoColl.getDb();
+        Collection* collection = autoColl.getCollection();
+        if (!collection) {
             if (db && ViewCatalog::get(db)->lookup(opCtx, nss.ns())) {
                 return Status(ErrorCodes::CommandNotSupportedOnView,
                               str::stream() << "Cannot drop indexes on view " << nss);
diff --git a/src/mongo/db/catalog/index_build_block.cpp b/src/mongo/db/catalog/index_build_block.cpp
index af1bd77af68..46231723f62 100644
--- a/src/mongo/db/catalog/index_build_block.cpp
+++ b/src/mongo/db/catalog/index_build_block.cpp
@@ -50,7 +50,7 @@ IndexCatalogImpl::IndexBuildBlock::IndexBuildBlock(IndexCatalogImpl* catalog,
                                                    const NamespaceString& nss,
                                                    const BSONObj& spec,
                                                    IndexBuildMethod method)
-    : _catalog(catalog), _ns(nss.ns()), _spec(spec.getOwned()), _method(method), _entry(nullptr) {}
+    : _catalog(catalog), _nss(nss), _spec(spec.getOwned()), _method(method), _entry(nullptr) {}
 
 void IndexCatalogImpl::IndexBuildBlock::deleteTemporaryTables(OperationContext* opCtx) {
     if (_indexBuildInterceptor) {
@@ -137,14 +137,7 @@ void IndexCatalogImpl::IndexBuildBlock::fail(OperationContext* opCtx,
     invariant(opCtx->lockState()->inAWriteUnitOfWork());
     fassert(17204, collection->ok());  // defensive
 
-    NamespaceString ns(_indexNamespace);
-    // TODO(SERVER-39520): Once createCollection does not need database IX lock, 'system.views' will
-    // be no longer a special case.
-    if (ns.coll().startsWith(NamespaceString::kSystemDotViewsCollectionName)) {
-        invariant(opCtx->lockState()->isDbLockedForMode(ns.db(), MODE_IX));
-    } else {
-        invariant(opCtx->lockState()->isDbLockedForMode(ns.db(), MODE_X));
-    }
+    invariant(opCtx->lockState()->isCollectionLockedForMode(_nss, MODE_X));
 
     if (_entry) {
         invariant(_catalog->_dropIndex(opCtx, _entry).isOK());
@@ -161,14 +154,7 @@ void IndexCatalogImpl::IndexBuildBlock::success(OperationContext* opCtx, Collect
     invariant(opCtx->lockState()->inAWriteUnitOfWork());
 
     fassert(17207, collection->ok());
-    NamespaceString ns(_indexNamespace);
-    // TODO(SERVER-39520): Once createCollection does not need database IX lock, 'system.views' will
-    // be no longer a special case.
-    if (ns.coll().startsWith(NamespaceString::kSystemDotViewsCollectionName)) {
-        invariant(opCtx->lockState()->isDbLockedForMode(ns.db(), MODE_IX));
-    } else {
-        invariant(opCtx->lockState()->isDbLockedForMode(ns.db(), MODE_X));
-    }
+    invariant(opCtx->lockState()->isCollectionLockedForMode(_nss, MODE_X));
 
     if (_indexBuildInterceptor) {
         // An index build should never be completed with writes remaining in the interceptor.
@@ -178,7 +164,7 @@ void IndexCatalogImpl::IndexBuildBlock::success(OperationContext* opCtx, Collect
         invariant(_indexBuildInterceptor->areAllConstraintsChecked(opCtx));
     }
 
-    log() << "index build: done building index " << _indexName << " on ns " << _ns;
+    log() << "index build: done building index " << _indexName << " on ns " << _nss;
 
     collection->indexBuildSuccess(opCtx, _entry);
 
diff --git a/src/mongo/db/catalog/index_catalog_impl.h b/src/mongo/db/catalog/index_catalog_impl.h
index 05d790b46b3..f7736b642fa 100644
--- a/src/mongo/db/catalog/index_catalog_impl.h
+++ b/src/mongo/db/catalog/index_catalog_impl.h
@@ -298,7 +298,7 @@ public:
 
     private:
         IndexCatalogImpl* const _catalog;
-        const std::string _ns;
+        const NamespaceString& _nss;
 
         BSONObj _spec;
         IndexBuildMethod _method;