6 files changed, 19 insertions, 8 deletions
diff --git a/src/mongo/db/catalog/database_impl.cpp b/src/mongo/db/catalog/database_impl.cpp
index bbebfc054f1..b1f70b658c9 100644
--- a/src/mongo/db/catalog/database_impl.cpp
+++ b/src/mongo/db/catalog/database_impl.cpp
@@ -584,6 +584,11 @@ void DatabaseImpl::_checkCanCreateCollection(OperationContext* opCtx,
             str::stream() << "cannot create a collection with an empty name on db: " << nss.db(),
             !nss.coll().empty());
 
+    uassert(17361,
+            str::stream() << "Fully qualified namespace is too long. Namespace: " << nss.ns()
+                          << " Max: " << NamespaceString::MaxNsCollectionLen,
+            !nss.isNormalCollection() || nss.size() <= NamespaceString::MaxNsCollectionLen);
+
     uassert(28838, "cannot create a non-capped oplog collection", options.capped || !nss.isOplog());
     uassert(ErrorCodes::DatabaseDropPending,
             str::stream() << "Cannot create collection " << nss
diff --git a/src/mongo/db/catalog/rename_collection_test.cpp b/src/mongo/db/catalog/rename_collection_test.cpp
index 6aaa602a075..0f8965a76db 100644
--- a/src/mongo/db/catalog/rename_collection_test.cpp
+++ b/src/mongo/db/catalog/rename_collection_test.cpp
@@ -549,7 +549,7 @@ TEST_F(RenameCollectionTest, RenameCollectionReturnsNotMasterIfNotPrimary) {
 
 TEST_F(RenameCollectionTest, TargetCollectionNameLong) {
     _createCollection(_opCtx.get(), _sourceNss);
-    const std::string targetCollectionName(500, 'a');
+    const std::string targetCollectionName(255, 'a');
     NamespaceString longTargetNss(_sourceNss.db(), targetCollectionName);
     ASSERT_OK(renameCollection(_opCtx.get(), _sourceNss, longTargetNss, {}));
 }
diff --git a/src/mongo/db/namespace_string.cpp b/src/mongo/db/namespace_string.cpp
index dd8f965afb5..54b333ed0a7 100644
--- a/src/mongo/db/namespace_string.cpp
+++ b/src/mongo/db/namespace_string.cpp
@@ -162,7 +162,7 @@ bool NamespaceString::checkLengthForFCV() const {
 
     if (serverGlobalParams.featureCompatibility.getVersion() ==
         ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo44) {
-        return true;
+        return size() <= MaxNsCollectionLen;
     }
 
     return false;
diff --git a/src/mongo/db/namespace_string.h b/src/mongo/db/namespace_string.h
index 4145ac25882..598ff87c4f0 100644
--- a/src/mongo/db/namespace_string.h
+++ b/src/mongo/db/namespace_string.h
@@ -43,10 +43,12 @@
 
 namespace mongo {
 
-const size_t MaxDatabaseNameLen = 128;  // max str len for the db name, including null char
-
 class NamespaceString {
 public:
+    constexpr static size_t MaxDatabaseNameLen =
+        128;  // max str len for the db name, including null char
+    constexpr static size_t MaxNsCollectionLen = 255;
+
     // Reserved system namespaces
 
     // Namespace for the admin database
@@ -470,10 +472,13 @@ StringBuilder& operator<<(StringBuilder& builder, const NamespaceStringOrUUID& n
 inline StringData nsToDatabaseSubstring(StringData ns) {
     size_t i = ns.find('.');
     if (i == std::string::npos) {
-        massert(10078, "nsToDatabase: db too long", ns.size() < MaxDatabaseNameLen);
+        massert(
+            10078, "nsToDatabase: db too long", ns.size() < NamespaceString::MaxDatabaseNameLen);
         return ns;
     }
-    massert(10088, "nsToDatabase: db too long", i < static_cast<size_t>(MaxDatabaseNameLen));
+    massert(10088,
+            "nsToDatabase: db too long",
+            i < static_cast<size_t>(NamespaceString::MaxDatabaseNameLen));
     return ns.substr(0, i);
 }
 
diff --git a/src/mongo/db/namespace_string_test.cpp b/src/mongo/db/namespace_string_test.cpp
index baba77e9855..b849284b99d 100644
--- a/src/mongo/db/namespace_string_test.cpp
+++ b/src/mongo/db/namespace_string_test.cpp
@@ -150,7 +150,7 @@ TEST(NamespaceStringTest, MakeDropPendingNamespace) {
                   NamespaceString{"test.foo"}.makeDropPendingNamespace(
                       repl::OpTime(Timestamp(Seconds(1234567), 8U), 9LL)));
 
-    std::string collName(8192, 't');
+    std::string collName(NamespaceString::MaxNsCollectionLen, 't');
     NamespaceString nss("test", collName);
     ASSERT_EQUALS(NamespaceString{"test.system.drop.1234567i8t9." + collName},
                   nss.makeDropPendingNamespace(repl::OpTime(Timestamp(Seconds(1234567), 8U), 9LL)));
diff --git a/src/mongo/db/repl/storage_interface_impl_test.cpp b/src/mongo/db/repl/storage_interface_impl_test.cpp
index 6c91cc5e090..9656b154a88 100644
--- a/src/mongo/db/repl/storage_interface_impl_test.cpp
+++ b/src/mongo/db/repl/storage_interface_impl_test.cpp
@@ -77,7 +77,8 @@ BSONObj makeIdIndexSpec(const NamespaceString& nss) {
  */
 template <typename T>
 NamespaceString makeNamespace(const T& t, const std::string& suffix = "") {
-    return NamespaceString(std::string("local." + t.getSuiteName() + "_" + t.getTestName()) +
+    return NamespaceString(std::string("local." + t.getSuiteName() + "_" + t.getTestName())
+                               .substr(0, NamespaceString::MaxNsCollectionLen - suffix.length()) +
                            suffix);
 }