SERVER-14567 Implement checkIfWriteConcernCanBeSatisfied in ReplicationCoordinatorImpl

8 files changed, 135 insertions, 16 deletions

diff --git a/src/mongo/db/commands/cleanup_orphaned_cmd.cpp b/src/mongo/db/commands/cleanup_orphaned_cmd.cpp
index 83dbea1166b..fe468c0b166 100644
--- a/src/mongo/db/commands/cleanup_orphaned_cmd.cpp
+++ b/src/mongo/db/commands/cleanup_orphaned_cmd.cpp
@@ -248,7 +248,7 @@ namespace mongo {
                 repl::ReplicationCoordinator* replCoordinator =
                         repl::getGlobalReplicationCoordinator();
                 Status status = replCoordinator->checkIfWriteConcernCanBeSatisfied(writeConcern);
-                if (!status.isOK()) {
+                if (!status.isOK() && status != ErrorCodes::NoReplicationEnabled) {
                     return appendCommandStatus(result, status);
                 }
             }
diff --git a/src/mongo/db/repl/repl_coordinator.h b/src/mongo/db/repl/repl_coordinator.h
index b4d91704039..683a8ea00ca 100644
--- a/src/mongo/db/repl/repl_coordinator.h
+++ b/src/mongo/db/repl/repl_coordinator.h
@@ -208,9 +208,9 @@ namespace repl {
          * Checks if the current replica set configuration can satisfy the given write concern.
          *
          * Things that are taken into consideration include:
-         * 1. If the set has enough members.
-         * 2. If the tag exists.
-         * 3. If there are enough members for the tag specified.
+         * 1. If the set has enough data-bearing members.
+         * 2. If the write concern mode exists.
+         * 3. If there are enough members for the write concern mode specified.
          */
         virtual Status checkIfWriteConcernCanBeSatisfied(
                 const WriteConcernOptions& writeConcern) const = 0;
diff --git a/src/mongo/db/repl/repl_coordinator_hybrid.cpp b/src/mongo/db/repl/repl_coordinator_hybrid.cpp
index f8c9f1241d1..a6544a487d0 100644
--- a/src/mongo/db/repl/repl_coordinator_hybrid.cpp
+++ b/src/mongo/db/repl/repl_coordinator_hybrid.cpp
@@ -383,9 +383,7 @@ namespace repl {
 
     Status HybridReplicationCoordinator::checkIfWriteConcernCanBeSatisfied(
             const WriteConcernOptions& writeConcern) const {
-        Status legacyStatus = _legacy.checkIfWriteConcernCanBeSatisfied(writeConcern);
-        Status implStatus = _impl.checkIfWriteConcernCanBeSatisfied(writeConcern);
-        return legacyStatus;
+        return _impl.checkIfWriteConcernCanBeSatisfied(writeConcern);
     }
 
     BSONObj HybridReplicationCoordinator::getGetLastErrorDefault() {
diff --git a/src/mongo/db/repl/repl_coordinator_impl.cpp b/src/mongo/db/repl/repl_coordinator_impl.cpp
index bc0ff5fedd5..3aa7c9a1a32 100644
--- a/src/mongo/db/repl/repl_coordinator_impl.cpp
+++ b/src/mongo/db/repl/repl_coordinator_impl.cpp
@@ -1251,16 +1251,22 @@ namespace {
 
     Status ReplicationCoordinatorImpl::_checkIfWriteConcernCanBeSatisfied_inlock(
                 const WriteConcernOptions& writeConcern) const {
-        // TODO Finish implementing this
+        if (_getReplicationMode_inlock() == modeNone) {
+            return Status(ErrorCodes::NoReplicationEnabled,
+                          "No replication enabled when checking if write concern can be satisfied");
+        }
 
-        if (!writeConcern.wMode.empty() && writeConcern.wMode != "majority") {
-            StatusWith<ReplicaSetTagPattern> tagPatternStatus =
-                    _rsConfig.findCustomWriteMode(writeConcern.wMode);
-            if (!tagPatternStatus.isOK()) {
-                return tagPatternStatus.getStatus();
+        if (_getReplicationMode_inlock() == modeMasterSlave) {
+            if (!writeConcern.wMode.empty()) {
+                return Status(ErrorCodes::UnknownReplWriteConcern,
+                              "Cannot used named write concern modes in master-slave");
             }
+            // No way to know how many slaves there are, so assume any numeric mode is possible.
+            return Status::OK();
         }
-        return Status::OK();
+
+        invariant(_getReplicationMode_inlock() == modeReplSet);
+        return _rsConfig.checkIfWriteConcernCanBeSatisfied(writeConcern);
     }
 
     BSONObj ReplicationCoordinatorImpl::getGetLastErrorDefault() {
diff --git a/src/mongo/db/repl/replica_set_config.cpp b/src/mongo/db/repl/replica_set_config.cpp
index 4e76121a3ca..fe6715365a9 100644
--- a/src/mongo/db/repl/replica_set_config.cpp
+++ b/src/mongo/db/repl/replica_set_config.cpp
@@ -345,6 +345,45 @@ namespace {
         return Status::OK();
     }
 
+    Status ReplicaSetConfig::checkIfWriteConcernCanBeSatisfied(
+            const WriteConcernOptions& writeConcern) const {
+        if (!writeConcern.wMode.empty() && writeConcern.wMode != "majority") {
+            StatusWith<ReplicaSetTagPattern> tagPatternStatus =
+                    findCustomWriteMode(writeConcern.wMode);
+            if (!tagPatternStatus.isOK()) {
+                return tagPatternStatus.getStatus();
+            }
+
+            ReplicaSetTagMatch matcher(tagPatternStatus.getValue());
+            for (size_t j = 0; j < _members.size(); ++j) {
+                const MemberConfig& memberConfig = _members[j];
+                for (MemberConfig::TagIterator it = memberConfig.tagsBegin();
+                        it != memberConfig.tagsEnd(); ++it) {
+                    if (matcher.update(*it)) {
+                        return Status::OK();
+                    }
+                }
+            }
+            // Even if all the nodes in the set had a given write it still would not satisfy this
+            // write concern mode.
+            return Status(ErrorCodes::CannotSatisfyWriteConcern,
+                          str::stream() << "Not enough nodes match write concern mode \""
+                                        << writeConcern.wMode << "\"");
+        }
+        else {
+            int nodesRemaining = writeConcern.wNumNodes;
+            for (size_t j = 0; j < _members.size(); ++j) {
+                if (!_members[j].isArbiter()) { // Only count data-bearing nodes
+                    --nodesRemaining;
+                    if (nodesRemaining <= 0) {
+                        return Status::OK();
+                    }
+                }
+            }
+            return Status(ErrorCodes::CannotSatisfyWriteConcern, "Not enough data-bearing nodes");
+        }
+    }
+
     const MemberConfig& ReplicaSetConfig::getMemberAt(size_t i) const { 
         invariant(i < _members.size());
         return _members[i]; 
diff --git a/src/mongo/db/repl/replica_set_config.h b/src/mongo/db/repl/replica_set_config.h
index 73571d780e1..0b16386a565 100644
--- a/src/mongo/db/repl/replica_set_config.h
+++ b/src/mongo/db/repl/replica_set_config.h
@@ -80,6 +80,16 @@ namespace repl {
         Status validate() const;
 
         /**
+         * Checks if this configuration can satisfy the given write concern.
+         *
+         * Things that are taken into consideration include:
+         * 1. If the set has enough data-bearing members.
+         * 2. If the write concern mode exists.
+         * 3. If there are enough members for the write concern mode specified.
+         */
+        Status checkIfWriteConcernCanBeSatisfied(const WriteConcernOptions& writeConcern) const;
+
+        /**
          * Gets the version of this configuration.
          *
          * The version number sequences configurations of the replica set, so that
diff --git a/src/mongo/db/repl/replica_set_config_test.cpp b/src/mongo/db/repl/replica_set_config_test.cpp
index 12db516089f..fc1ba7ff8ed 100644
--- a/src/mongo/db/repl/replica_set_config_test.cpp
+++ b/src/mongo/db/repl/replica_set_config_test.cpp
@@ -540,6 +540,72 @@ namespace {
         ASSERT_TRUE(configA == configB);
     }
 
+    TEST(ReplicaSetConfig, CheckIfWriteConcernCanBeSatisfied) {
+        ReplicaSetConfig configA;
+        ASSERT_OK(configA.initialize(
+                BSON("_id" << "rs0" <<
+                     "version" << 1 <<
+                     "members" << BSON_ARRAY(BSON("_id" << 0 <<
+                                                 "host" << "node0" <<
+                                                 "tags" << BSON("dc" << "NA" <<
+                                                                "rack" << "rackNA1")) <<
+                                             BSON("_id" << 1 <<
+                                                  "host" << "node1" <<
+                                                  "tags" << BSON("dc" << "NA" <<
+                                                                 "rack" << "rackNA2")) <<
+                                             BSON("_id" << 2 <<
+                                                  "host" << "node2" <<
+                                                  "tags" << BSON("dc" << "NA" <<
+                                                                 "rack" << "rackNA3")) <<
+                                             BSON("_id" << 3 <<
+                                                  "host" << "node3" <<
+                                                  "tags" << BSON("dc" << "EU" <<
+                                                                 "rack" << "rackEU1")) <<
+                                             BSON("_id" << 4 <<
+                                                  "host" << "node4" <<
+                                                  "tags" << BSON("dc" << "EU" <<
+                                                                 "rack" << "rackEU2")) <<
+                                             BSON("_id" << 5 <<
+                                                  "host" << "node5" <<
+                                                  "arbiterOnly" << true)) <<
+                     "settings" << BSON("getLastErrorModes" <<
+                             BSON("valid" << BSON("dc" << 2 << "rack" << 3) <<
+                                  "invalidNotEnoughValues" << BSON("dc" << 3) <<
+                                  "invalidNotEnoughNodes" << BSON("rack" << 6))))));
+
+        WriteConcernOptions validNumberWC;
+        validNumberWC.wNumNodes = 5;
+        ASSERT_OK(configA.checkIfWriteConcernCanBeSatisfied(validNumberWC));
+
+        WriteConcernOptions invalidNumberWC;
+        invalidNumberWC.wNumNodes = 6;
+        ASSERT_EQUALS(ErrorCodes::CannotSatisfyWriteConcern,
+                      configA.checkIfWriteConcernCanBeSatisfied(invalidNumberWC));
+
+        WriteConcernOptions majorityWC;
+        majorityWC.wMode = "majority";
+        ASSERT_OK(configA.checkIfWriteConcernCanBeSatisfied(majorityWC));
+
+        WriteConcernOptions validModeWC;
+        validModeWC.wMode = "valid";
+        ASSERT_OK(configA.checkIfWriteConcernCanBeSatisfied(validModeWC));
+
+        WriteConcernOptions fakeModeWC;
+        fakeModeWC.wMode = "fake";
+        ASSERT_EQUALS(ErrorCodes::UnknownReplWriteConcern,
+                      configA.checkIfWriteConcernCanBeSatisfied(fakeModeWC));
+
+        WriteConcernOptions invalidModeNotEnoughValuesWC;
+        invalidModeNotEnoughValuesWC.wMode = "invalidNotEnoughValues";
+        ASSERT_EQUALS(ErrorCodes::CannotSatisfyWriteConcern,
+                      configA.checkIfWriteConcernCanBeSatisfied(invalidModeNotEnoughValuesWC));
+
+        WriteConcernOptions invalidModeNotEnoughNodesWC;
+        invalidModeNotEnoughNodesWC.wMode = "invalidNotEnoughNodes";
+        ASSERT_EQUALS(ErrorCodes::CannotSatisfyWriteConcern,
+                      configA.checkIfWriteConcernCanBeSatisfied(invalidModeNotEnoughNodesWC));
+    }
+
 }  // namespace
 }  // namespace repl
 }  // namespace mongo
diff --git a/src/mongo/s/d_migrate.cpp b/src/mongo/s/d_migrate.cpp
index 4ae6c54bfa8..2c36511c602 100644
--- a/src/mongo/s/d_migrate.cpp
+++ b/src/mongo/s/d_migrate.cpp
@@ -864,7 +864,7 @@ namespace mongo {
                 repl::ReplicationCoordinator* replCoordinator =
                         repl::getGlobalReplicationCoordinator();
                 Status status = replCoordinator->checkIfWriteConcernCanBeSatisfied(writeConcern);
-                if (!status.isOK()) {
+                if (!status.isOK() && status != ErrorCodes::NoReplicationEnabled) {
                     warning() << status.toString() << endl;
                     return appendCommandStatus(result, status);
                 }
@@ -2435,7 +2435,7 @@ namespace mongo {
                 repl::ReplicationCoordinator* replCoordinator =
                         repl::getGlobalReplicationCoordinator();
                 Status status = replCoordinator->checkIfWriteConcernCanBeSatisfied(writeConcern);
-                if (!status.isOK()) {
+                if (!status.isOK() && status != ErrorCodes::NoReplicationEnabled) {
                     warning() << status.toString() << endl;
                     return appendCommandStatus(result, status);
                 }