1 files changed, 27 insertions, 45 deletions

diff --git a/src/mongo/db/write_concern.cpp b/src/mongo/db/write_concern.cpp
index ef19e3646f6..94d5350dfc1 100644
--- a/src/mongo/db/write_concern.cpp
+++ b/src/mongo/db/write_concern.cpp
@@ -37,7 +37,6 @@
 #include "mongo/bson/util/bson_extract.h"
 #include "mongo/db/client.h"
 #include "mongo/db/commands/server_status_metric.h"
-#include "mongo/db/curop.h"
 #include "mongo/db/operation_context.h"
 #include "mongo/db/read_write_concern_defaults.h"
 #include "mongo/db/repl/optime.h"
@@ -98,34 +97,28 @@ StatusWith<WriteConcernOptions> extractWriteConcern(OperationContext* opCtx,
     bool clientSuppliedWriteConcern = !writeConcern.usedDefaultConstructedWC;
     bool customDefaultWasApplied = false;
 
-    // WriteConcern defaults can only be applied on regular replica set members.
-    // Operations received by shard and config servers should always have WC explicitly specified.
-    bool canApplyDefaultWC = serverGlobalParams.clusterRole == ClusterRole::None &&
-        repl::ReplicationCoordinator::get(opCtx)->isReplEnabled() &&
-        (!opCtx->inMultiDocumentTransaction() ||
-         isTransactionCommand(cmdObj.firstElementFieldName())) &&
-        !opCtx->getClient()->isInDirectClient() && !isInternalClient;
-
     // If no write concern is specified in the command, then use the cluster-wide default WC (if
-    // there is one), or else the default implicit WC:
-    // (if [(#arbiters > 0) AND (#arbiters >= ½(#voting nodes) - 1)] then {w:1} else {w:majority}).
-    if (canApplyDefaultWC) {
-        auto getDefaultWC = ([&]() {
-            auto rwcDefaults =
-                ReadWriteConcernDefaults::get(opCtx->getServiceContext()).getDefault(opCtx);
-            auto wcDefault = rwcDefaults.getDefaultWriteConcern();
-            const auto defaultWriteConcernSource = rwcDefaults.getDefaultWriteConcernSource();
-            customDefaultWasApplied = defaultWriteConcernSource &&
-                defaultWriteConcernSource == DefaultWriteConcernSourceEnum::kGlobal;
-            return wcDefault;
-        });
-
-
-        if (!clientSuppliedWriteConcern) {
-            writeConcern = ([&]() {
-                auto wcDefault = getDefaultWC();
-                // Default WC can be 'boost::none' if the implicit default is used and set to 'w:1'.
+    // there is one), or else the default WC {w:1}.
+    if (!clientSuppliedWriteConcern) {
+        writeConcern = ([&]() {
+            // WriteConcern defaults can only be applied on regular replica set members.  Operations
+            // received by shard and config servers should always have WC explicitly specified.
+            if (serverGlobalParams.clusterRole != ClusterRole::ShardServer &&
+                serverGlobalParams.clusterRole != ClusterRole::ConfigServer &&
+                repl::ReplicationCoordinator::get(opCtx)->isReplEnabled() &&
+                (!opCtx->inMultiDocumentTransaction() ||
+                 isTransactionCommand(cmdObj.firstElementFieldName())) &&
+                !opCtx->getClient()->isInDirectClient() && !isInternalClient) {
+
+                const auto rwcDefaults =
+                    ReadWriteConcernDefaults::get(opCtx->getServiceContext()).getDefault(opCtx);
+                auto wcDefault = rwcDefaults.getDefaultWriteConcern();
                 if (wcDefault) {
+                    const auto defaultWriteConcernSource =
+                        rwcDefaults.getDefaultWriteConcernSource();
+                    customDefaultWasApplied = defaultWriteConcernSource &&
+                        defaultWriteConcernSource == DefaultWriteConcernSourceEnum::kGlobal;
+
                     LOGV2_DEBUG(22548,
                                 2,
                                 "Applying default writeConcern on {cmdObj_firstElementFieldName} "
@@ -135,22 +128,15 @@ StatusWith<WriteConcernOptions> extractWriteConcern(OperationContext* opCtx,
                                 "wcDefault"_attr = wcDefault->toBSON());
                     return *wcDefault;
                 }
-                return writeConcern;
-            })();
-            writeConcern.notExplicitWValue = true;
-        }
-        // Client supplied a write concern object without 'w' field.
-        else if (writeConcern.isExplicitWithoutWField()) {
-            auto wcDefault = getDefaultWC();
-            // Default WC can be 'boost::none' if the implicit default is used and set to 'w:1'.
-            if (wcDefault) {
-                clientSuppliedWriteConcern = false;
-                writeConcern.w = wcDefault->w;
-                if (writeConcern.syncMode == WriteConcernOptions::SyncMode::UNSET) {
-                    writeConcern.syncMode = wcDefault->syncMode;
-                }
             }
+            return writeConcern;
+        })();
+
+        if (writeConcern.isUnacknowledged()) {
+            writeConcern.w = 1;
         }
+
+        writeConcern.notExplicitWValue = true;
     }
 
     // It's fine for clients to provide any provenance value to mongod. But if they haven't, then an
@@ -286,10 +272,6 @@ Status waitForWriteConcern(OperationContext* opCtx,
                 "replOpTime"_attr = replOpTime,
                 "writeConcern"_attr = writeConcern.toBSON());
 
-    // Add time waiting for write concern to CurOp.
-    CurOp::get(opCtx)->beginWaitForWriteConcernTimer();
-    ScopeGuard finishTiming([&] { CurOp::get(opCtx)->stopWaitForWriteConcernTimer(); });
-
     auto* const storageEngine = opCtx->getServiceContext()->getStorageEngine();
     auto const replCoord = repl::ReplicationCoordinator::get(opCtx);