SERVER-20224 Now only the command processor calls txn->setWriteConcern()

It also restores the original writeConcern when it is done.

7 files changed, 27 insertions, 60 deletions

diff --git a/src/mongo/db/commands/get_last_error.cpp b/src/mongo/db/commands/get_last_error.cpp
index 19d262e4df5..7af1a83aafa 100644
--- a/src/mongo/db/commands/get_last_error.cpp
+++ b/src/mongo/db/commands/get_last_error.cpp
@@ -262,14 +262,13 @@ public:
             }
         }
 
-        txn->setWriteConcern(writeConcern);
         {
             stdx::lock_guard<Client> lk(*txn->getClient());
             txn->setMessage_inlock("waiting for write concern");
         }
 
         WriteConcernResult wcResult;
-        status = waitForWriteConcern(txn, lastOpTime, txn->getWriteConcern(), &wcResult);
+        status = waitForWriteConcern(txn, lastOpTime, writeConcern, &wcResult);
         wcResult.appendTo(writeConcern, &result);
 
         // For backward compatibility with 2.4, wtimeout returns ok : 1.0
diff --git a/src/mongo/db/commands/mr.cpp b/src/mongo/db/commands/mr.cpp
index 3f0b2643af8..56bd3f7fcf2 100644
--- a/src/mongo/db/commands/mr.cpp
+++ b/src/mongo/db/commands/mr.cpp
@@ -616,7 +616,7 @@ long long State::postProcessCollectionNonAtomic(OperationContext* txn,
         ScopedTransaction transaction(txn, MODE_X);
         Lock::GlobalWrite lock(txn->lockState());  // TODO(erh): why global???
         // replace: just rename from temp to final collection name, dropping previous collection
-        _db.dropCollection(_config.outputOptions.finalNamespace, txn->getWriteConcern());
+        _db.dropCollection(_config.outputOptions.finalNamespace);
         BSONObj info;
 
         if (!_db.runCommand("admin",
@@ -627,7 +627,7 @@ long long State::postProcessCollectionNonAtomic(OperationContext* txn,
             uasserted(10076, str::stream() << "rename failed: " << info);
         }
 
-        _db.dropCollection(_config.tempNamespace, txn->getWriteConcern());
+        _db.dropCollection(_config.tempNamespace);
     } else if (_config.outputOptions.outType == Config::MERGE) {
         // merge: upsert new docs into old collection
         {
@@ -646,7 +646,7 @@ long long State::postProcessCollectionNonAtomic(OperationContext* txn,
             Helpers::upsert(_txn, _config.outputOptions.finalNamespace, o);
             pm.hit();
         }
-        _db.dropCollection(_config.tempNamespace, txn->getWriteConcern());
+        _db.dropCollection(_config.tempNamespace);
         pm.finished();
     } else if (_config.outputOptions.outType == Config::REDUCE) {
         // reduce: apply reduce op on new result and existing one
@@ -1325,11 +1325,6 @@ public:
              BSONObjBuilder& result) {
         Timer t;
 
-        // Save and reset the write concern so that it doesn't get changed accidentally by
-        // DBDirectClient.
-        auto oldWC = txn->getWriteConcern();
-        ON_BLOCK_EXIT([txn, oldWC] { txn->setWriteConcern(oldWC); });
-
         boost::optional<DisableDocumentValidation> maybeDisableValidation;
         if (shouldBypassDocumentValidationForCommand(cmd))
             maybeDisableValidation.emplace(txn);
@@ -1655,11 +1650,6 @@ public:
                                      << dbname));
         }
 
-        // Save and reset the write concern so that it doesn't get changed accidentally by
-        // DBDirectClient.
-        auto oldWC = txn->getWriteConcern();
-        ON_BLOCK_EXIT([txn, oldWC] { txn->setWriteConcern(oldWC); });
-
         boost::optional<DisableDocumentValidation> maybeDisableValidation;
         if (shouldBypassDocumentValidationForCommand(cmdObj))
             maybeDisableValidation.emplace(txn);
diff --git a/src/mongo/db/commands/pipeline_command.cpp b/src/mongo/db/commands/pipeline_command.cpp
index 6f63dd9fbd4..4eb8444951f 100644
--- a/src/mongo/db/commands/pipeline_command.cpp
+++ b/src/mongo/db/commands/pipeline_command.cpp
@@ -54,7 +54,6 @@
 #include "mongo/db/query/plan_summary_stats.h"
 #include "mongo/db/storage/storage_options.h"
 #include "mongo/stdx/memory.h"
-#include "mongo/util/scopeguard.h"
 
 namespace mongo {
 
@@ -204,11 +203,6 @@ public:
         if (!pPipeline.get())
             return false;
 
-        // Save and reset the write concern so that it doesn't get changed accidentally by
-        // DBDirectClient.
-        auto oldWC = txn->getWriteConcern();
-        ON_BLOCK_EXIT([txn, oldWC] { txn->setWriteConcern(oldWC); });
-
         // This is outside of the if block to keep the object alive until the pipeline is finished.
         BSONObj parsed;
         if (kDebugBuild && !pPipeline->isExplain() && !pCtx->inShard) {
diff --git a/src/mongo/db/commands/user_management_commands.cpp b/src/mongo/db/commands/user_management_commands.cpp
index 68c5d862081..696339496eb 100644
--- a/src/mongo/db/commands/user_management_commands.cpp
+++ b/src/mongo/db/commands/user_management_commands.cpp
@@ -73,7 +73,6 @@
 #include "mongo/util/log.h"
 #include "mongo/util/mongoutils/str.h"
 #include "mongo/util/net/ssl_manager.h"
-#include "mongo/util/scopeguard.h"
 #include "mongo/util/sequence_util.h"
 #include "mongo/util/time_support.h"
 
@@ -265,11 +264,6 @@ Status queryAuthzDocument(OperationContext* txn,
 Status insertAuthzDocument(OperationContext* txn,
                            const NamespaceString& collectionName,
                            const BSONObj& document) {
-    // Save and reset the write concern so that it doesn't get changed accidentally by
-    // DBDirectClient.
-    auto oldWC = txn->getWriteConcern();
-    ON_BLOCK_EXIT([txn, oldWC] { txn->setWriteConcern(oldWC); });
-
     try {
         DBDirectClient client(txn);
 
@@ -304,11 +298,6 @@ Status updateAuthzDocuments(OperationContext* txn,
                             bool upsert,
                             bool multi,
                             long long* nMatched) {
-    // Save and reset the write concern so that it doesn't get changed accidentally by
-    // DBDirectClient.
-    auto oldWC = txn->getWriteConcern();
-    ON_BLOCK_EXIT([txn, oldWC] { txn->setWriteConcern(oldWC); });
-
     try {
         DBDirectClient client(txn);
 
@@ -379,11 +368,6 @@ Status removeAuthzDocuments(OperationContext* txn,
                             const NamespaceString& collectionName,
                             const BSONObj& query,
                             long long* numRemoved) {
-    // Save and reset the write concern so that it doesn't get changed accidentally by
-    // DBDirectClient.
-    auto oldWC = txn->getWriteConcern();
-    ON_BLOCK_EXIT([txn, oldWC] { txn->setWriteConcern(oldWC); });
-
     try {
         DBDirectClient client(txn);
 
diff --git a/src/mongo/db/dbcommands.cpp b/src/mongo/db/dbcommands.cpp
index b1fbd59940c..cefb565eac0 100644
--- a/src/mongo/db/dbcommands.cpp
+++ b/src/mongo/db/dbcommands.cpp
@@ -1540,28 +1540,26 @@ bool Command::run(OperationContext* txn,
         return result;
     }
 
-    if (this->supportsWriteConcern(cmd)) {
+    bool result;
+    if (!this->supportsWriteConcern(cmd)) {
+        // TODO: remove queryOptions parameter from command's run method.
+        result = this->run(txn, db, cmd, 0, errmsg, inPlaceReplyBob);
+    } else {
+        // Change the write concern while running the command.
+        const auto oldWC = txn->getWriteConcern();
+        ON_BLOCK_EXIT([&] { txn->setWriteConcern(oldWC); });
         txn->setWriteConcern(wcResult.getValue());
-    }
 
-    // TODO: remove queryOptions parameter from command's run method.
-    bool result = this->run(txn, db, cmd, 0, errmsg, inPlaceReplyBob);
+        result = this->run(txn, db, cmd, 0, errmsg, inPlaceReplyBob);
 
-    if (this->supportsWriteConcern(cmd)) {
-        if (shouldLog(logger::LogSeverity::Debug(1))) {
-            BSONObj oldWC = wcResult.getValue().toBSON();
-            BSONObj newWC = txn->getWriteConcern().toBSON();
-            if (oldWC != newWC) {
-                LOG(1) << "Provided writeConcern was overridden from " << oldWC << " to " << newWC
-                       << " for command " << cmd;
-            }
-        }
+        // Nothing in run() should change the writeConcern.
+        dassert(txn->getWriteConcern().toBSON() == wcResult.getValue().toBSON());
 
         WriteConcernResult res;
         auto waitForWCStatus =
             waitForWriteConcern(txn,
                                 repl::ReplClientInfo::forClient(txn->getClient()).getLastOp(),
-                                txn->getWriteConcern(),
+                                wcResult.getValue(),
                                 &res);
         appendCommandWCStatus(inPlaceReplyBob, waitForWCStatus, res);
 
diff --git a/src/mongo/db/ops/write_ops_exec.cpp b/src/mongo/db/ops/write_ops_exec.cpp
index 9f29bd1f65d..72366ef131e 100644
--- a/src/mongo/db/ops/write_ops_exec.cpp
+++ b/src/mongo/db/ops/write_ops_exec.cpp
@@ -276,11 +276,6 @@ static WriteResult performCreateIndexes(OperationContext* txn, const InsertOp& w
     // seem worth it since users that want faster index builds should just use the createIndexes
     // command rather than a legacy emulation.
     LastOpFixer lastOpFixer(txn, wholeOp.ns);
-
-    // Creating an index can change the writeConcern. Make sure we set it back to what it was.
-    const auto oldWC = txn->getWriteConcern();
-    ON_BLOCK_EXIT([&] { txn->setWriteConcern(oldWC); });
-
     WriteResult out;
     for (auto&& spec : wholeOp.documents) {
         try {
diff --git a/src/mongo/s/s_only.cpp b/src/mongo/s/s_only.cpp
index 1cecb1aba3d..8d63a0cb05b 100644
--- a/src/mongo/s/s_only.cpp
+++ b/src/mongo/s/s_only.cpp
@@ -48,6 +48,7 @@
 #include "mongo/util/assert_util.h"
 #include "mongo/util/concurrency/thread_name.h"
 #include "mongo/util/log.h"
+#include "mongo/util/scopeguard.h"
 
 namespace mongo {
 
@@ -139,14 +140,20 @@ void Command::execCommandClientBasic(OperationContext* txn,
         return;
     }
 
-    if (supportsWriteConcern) {
-        txn->setWriteConcern(wcResult.getValue());
-    }
 
     std::string errmsg;
     bool ok = false;
     try {
-        ok = c->run(txn, dbname, cmdObj, queryOptions, errmsg, result);
+        if (!supportsWriteConcern) {
+            ok = c->run(txn, dbname, cmdObj, queryOptions, errmsg, result);
+        } else {
+            // Change the write concern while running the command.
+            const auto oldWC = txn->getWriteConcern();
+            ON_BLOCK_EXIT([&] { txn->setWriteConcern(oldWC); });
+            txn->setWriteConcern(wcResult.getValue());
+
+            ok = c->run(txn, dbname, cmdObj, queryOptions, errmsg, result);
+        }
     } catch (const DBException& e) {
         result.resetToEmpty();
         const int code = e.getCode();