SERVER-65012 Avoid invariant when converting write-blocked shard to replicaSet

2 files changed, 3 insertions, 2 deletions

diff --git a/src/mongo/db/s/global_user_write_block_state.cpp b/src/mongo/db/s/global_user_write_block_state.cpp
index ec3dbf11f7e..af9adf72b3d 100644
--- a/src/mongo/db/s/global_user_write_block_state.cpp
+++ b/src/mongo/db/s/global_user_write_block_state.cpp
@@ -71,7 +71,6 @@ bool GlobalUserWriteBlockState::isUserWriteBlockingEnabled(OperationContext* opC
 }
 
 void GlobalUserWriteBlockState::enableUserShardedDDLBlocking(OperationContext* opCtx) {
-    invariant(serverGlobalParams.clusterRole == ClusterRole::ShardServer);
     _userShardedDDLBlocked.store(true);
 }
 
diff --git a/src/mongo/db/user_write_block_mode_op_observer.cpp b/src/mongo/db/user_write_block_mode_op_observer.cpp
index b58f48c623a..93a7fb2749c 100644
--- a/src/mongo/db/user_write_block_mode_op_observer.cpp
+++ b/src/mongo/db/user_write_block_mode_op_observer.cpp
@@ -177,7 +177,9 @@ void UserWriteBlockModeOpObserver::_onReplicationRollback(OperationContext* opCt
 
 void UserWriteBlockModeOpObserver::_checkWriteAllowed(OperationContext* opCtx,
                                                       const NamespaceString& nss) {
-    if (isStandaloneOrPrimary(opCtx)) {
+    // Evaluate write blocking only on replica set primaries.
+    const auto replCoord = repl::ReplicationCoordinator::get(opCtx);
+    if (replCoord->isReplEnabled() && isStandaloneOrPrimary(opCtx)) {
         GlobalUserWriteBlockState::get(opCtx)->checkUserWritesAllowed(opCtx, nss);
     }
 }