diff options
Diffstat (limited to 'src/mongo/db')
-rw-r--r-- | src/mongo/db/commands/feature_compatibility_version.cpp | 51 | ||||
-rw-r--r-- | src/mongo/db/commands/feature_compatibility_version.h | 4 |
2 files changed, 49 insertions, 6 deletions
diff --git a/src/mongo/db/commands/feature_compatibility_version.cpp b/src/mongo/db/commands/feature_compatibility_version.cpp index 616fee9802b..38bc3fc92f8 100644 --- a/src/mongo/db/commands/feature_compatibility_version.cpp +++ b/src/mongo/db/commands/feature_compatibility_version.cpp @@ -62,6 +62,10 @@ namespace mongo { using repl::UnreplicatedWritesBlock; Lock::ResourceMutex FeatureCompatibilityVersion::fcvLock("featureCompatibilityVersionLock"); +// lastFCVUpdateTimestamp contains the latest oplog entry timestamp which updated the FCV. +// It is reset on rollback. +Timestamp lastFCVUpdateTimestamp; +SimpleMutex lastFCVUpdateTimestampMutex; MONGO_FAIL_POINT_DEFINE(hangBeforeAbortingRunningTransactionsOnFCVDowngrade); @@ -162,7 +166,7 @@ void FeatureCompatibilityVersion::onInsertOrUpdate(OperationContext* opCtx, cons } opCtx->recoveryUnit()->onCommit( - [opCtx, newVersion](boost::optional<Timestamp>) { _setVersion(opCtx, newVersion); }); + [opCtx, newVersion](boost::optional<Timestamp> ts) { _setVersion(opCtx, newVersion, ts); }); } void FeatureCompatibilityVersion::updateMinWireVersion() { @@ -186,7 +190,17 @@ void FeatureCompatibilityVersion::updateMinWireVersion() { } void FeatureCompatibilityVersion::_setVersion( - OperationContext* opCtx, ServerGlobalParams::FeatureCompatibility::Version newVersion) { + OperationContext* opCtx, + ServerGlobalParams::FeatureCompatibility::Version newVersion, + boost::optional<Timestamp> commitTs) { + // We set the last FCV update timestamp before setting the new FCV, to make sure we never + // read an FCV that is not stable. We might still read a stale one. + { + stdx::lock_guard lk(lastFCVUpdateTimestampMutex); + if (commitTs && *commitTs > lastFCVUpdateTimestamp) { + lastFCVUpdateTimestamp = *commitTs; + } + } serverGlobalParams.featureCompatibility.setVersion(newVersion); updateMinWireVersion(); @@ -229,7 +243,10 @@ void FeatureCompatibilityVersion::onReplicationRollback(OperationContext* opCtx) << FeatureCompatibilityVersionParser::toString(memoryFcv) << "' to '" << FeatureCompatibilityVersionParser::toString(diskFcv) << "' as part of rollback."; - _setVersion(opCtx, diskFcv); + _setVersion(opCtx, diskFcv, boost::none); + // The rollback FCV is already in the stable snapshot. + stdx::lock_guard lk(lastFCVUpdateTimestampMutex); + lastFCVUpdateTimestamp = Timestamp(); } } } @@ -301,7 +318,7 @@ void FeatureCompatibilityVersionParameter::append(OperationContext* opCtx, featureCompatibilityVersionBuilder.append( FeatureCompatibilityVersionParser::kVersionField, FeatureCompatibilityVersionParser::kVersion42); - return; + break; case ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo42: featureCompatibilityVersionBuilder.append( FeatureCompatibilityVersionParser::kVersionField, @@ -322,11 +339,35 @@ void FeatureCompatibilityVersionParameter::append(OperationContext* opCtx, featureCompatibilityVersionBuilder.append( FeatureCompatibilityVersionParser::kVersionField, FeatureCompatibilityVersionParser::kVersion40); - return; + break; case ServerGlobalParams::FeatureCompatibility::Version::kUnsetDefault40Behavior: // getVersion() does not return this value. MONGO_UNREACHABLE; } + // If the FCV has been recently set to the fully upgraded FCV but is not part of the majority + // snapshot, then if we do a binary upgrade, we may see the old FCV at startup. + // It is not safe to do oplog application on the new binary at that point. So we make sure + // that when we report the FCV, it is in the majority snapshot. + // (The same consideration applies at downgrade, where if a recently-set fully downgraded FCV + // is not part of the majority snapshot, the downgraded binary will see the upgrade FCV and + // fail.) + const auto replCoordinator = repl::ReplicationCoordinator::get(opCtx); + const bool isReplSet = replCoordinator && + replCoordinator->getReplicationMode() == repl::ReplicationCoordinator::modeReplSet; + auto neededMajorityTimestamp = [] { + stdx::lock_guard lk(lastFCVUpdateTimestampMutex); + return lastFCVUpdateTimestamp; + }(); + if (isReplSet && !neededMajorityTimestamp.isNull()) { + auto status = replCoordinator->awaitTimestampCommitted(opCtx, neededMajorityTimestamp); + // If majority reads are not supported, we will take a full snapshot on clean shutdown + // and the new FCV will be included, so upgrade is possible. + if (status.code() != ErrorCodes::CommandNotSupported) + uassertStatusOK( + status.withContext("Most recent 'featureCompatibilityVersion' was not in the " + "majority snapshot on this node")); + } + return; } Status FeatureCompatibilityVersionParameter::setFromString(const std::string&) { diff --git a/src/mongo/db/commands/feature_compatibility_version.h b/src/mongo/db/commands/feature_compatibility_version.h index 0e06d36488f..1262138a017 100644 --- a/src/mongo/db/commands/feature_compatibility_version.h +++ b/src/mongo/db/commands/feature_compatibility_version.h @@ -120,9 +120,11 @@ private: /** * Set the FCV to newVersion, making sure to close any outgoing connections with incompatible * servers and closing open transactions if necessary. Increments the server TopologyVersion. + * If the commitTimestamp is set, advances the lastFCVUpdateTimestamp to it. */ static void _setVersion(OperationContext* opCtx, - ServerGlobalParams::FeatureCompatibility::Version newVersion); + ServerGlobalParams::FeatureCompatibility::Version newVersion, + boost::optional<Timestamp> commitTimestamp); }; |