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/**
* Copyright (C) 2020-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#include "mongo/db/op_observer/fcv_op_observer.h"
#include "mongo/db/commands/feature_compatibility_version.h"
#include "mongo/db/commands/feature_compatibility_version_parser.h"
#include "mongo/db/kill_sessions_local.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/op_observer/op_observer_util.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/repl/replication_coordinator.h"
#include "mongo/db/server_options.h"
#include "mongo/executor/egress_tag_closer_manager.h"
#include "mongo/logv2/log.h"
#include "mongo/transport/service_entry_point.h"
#include "mongo/util/assert_util.h"
#include "mongo/util/fail_point.h"
#define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kReplication
namespace mongo {
MONGO_FAIL_POINT_DEFINE(pauseBeforeCloseCxns);
MONGO_FAIL_POINT_DEFINE(finishedDropConnections);
void FcvOpObserver::_setVersion(OperationContext* opCtx,
multiversion::FeatureCompatibilityVersion 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.
if (commitTs)
FeatureCompatibilityVersion::advanceLastFCVUpdateTimestamp(*commitTs);
boost::optional<multiversion::FeatureCompatibilityVersion> prevVersion;
if (serverGlobalParams.featureCompatibility.isVersionInitialized()) {
prevVersion = serverGlobalParams.featureCompatibility.getVersion();
}
serverGlobalParams.mutableFeatureCompatibility.setVersion(newVersion);
serverGlobalParams.featureCompatibility.logFCVWithContext("setFCV"_sd);
FeatureCompatibilityVersion::updateMinWireVersion();
// (Generic FCV reference): This FCV check should exist across LTS binary versions.
if (serverGlobalParams.featureCompatibility.isGreaterThanOrEqualTo(
multiversion::GenericFCV::kLatest) ||
serverGlobalParams.featureCompatibility.isUpgradingOrDowngrading()) {
// minWireVersion == maxWireVersion on kLatest FCV or upgrading/downgrading FCV.
// Close all incoming connections from internal clients with binary versions lower than
// ours.
opCtx->getServiceContext()->getServiceEntryPoint()->endAllSessions(
transport::Session::kLatestVersionInternalClientKeepOpen |
transport::Session::kExternalClientKeepOpen);
// Close all outgoing connections to servers with binary versions lower than ours.
pauseBeforeCloseCxns.pauseWhileSet();
executor::EgressTagCloserManager::get(opCtx->getServiceContext())
.dropConnections(transport::Session::kKeepOpen | transport::Session::kPending);
if (MONGO_unlikely(finishedDropConnections.shouldFail())) {
LOGV2(575210, "Hit finishedDropConnections failpoint");
}
}
// We make assumptions that transactions don't span an FCV change. And FCV changes also take
// the global lock in S mode to create a barrier for operations in IX/X mode, we abort all open
// transactions here to release the global IX locks held by the transactions more proactively
// rather than waiting for the transactions to complete. FCV changes take the global S lock when
// in the upgrading/downgrading state.
// (Generic FCV reference): This FCV check should exist across LTS binary versions.
if (serverGlobalParams.featureCompatibility.isUpgradingOrDowngrading()) {
SessionKiller::Matcher matcherAllSessions(
KillAllSessionsByPatternSet{makeKillAllSessionsByPattern(opCtx)});
killSessionsAbortUnpreparedTransactions(opCtx, matcherAllSessions);
}
const auto replCoordinator = repl::ReplicationCoordinator::get(opCtx);
const bool isReplSet =
replCoordinator->getReplicationMode() == repl::ReplicationCoordinator::modeReplSet;
// We only want to increment the server TopologyVersion when the minWireVersion has changed.
// This can only happen in two scenarios:
// 1. Setting featureCompatibilityVersion from downgrading to fullyDowngraded.
// 2. Setting featureCompatibilityVersion from fullyDowngraded to upgrading.
// (Generic FCV reference): This FCV check should exist across LTS binary versions.
const auto shouldIncrementTopologyVersion = newVersion == multiversion::GenericFCV::kLastLTS ||
(prevVersion &&
prevVersion.get() == multiversion::GenericFCV::kDowngradingFromLatestToLastContinuous) ||
newVersion == multiversion::GenericFCV::kUpgradingFromLastLTSToLatest ||
newVersion == multiversion::GenericFCV::kUpgradingFromLastContinuousToLatest ||
newVersion == multiversion::GenericFCV::kUpgradingFromLastLTSToLastContinuous;
if (isReplSet && shouldIncrementTopologyVersion) {
replCoordinator->incrementTopologyVersion();
}
}
void FcvOpObserver::_onInsertOrUpdate(OperationContext* opCtx, const BSONObj& doc) {
auto idElement = doc["_id"];
if (idElement.type() != BSONType::String ||
idElement.String() != multiversion::kParameterName) {
return;
}
auto newVersion = uassertStatusOK(FeatureCompatibilityVersionParser::parse(doc));
// To avoid extra log messages when the targetVersion is set/unset, only log when the version
// changes.
logv2::DynamicAttributes attrs;
bool isDifferent = true;
if (serverGlobalParams.featureCompatibility.isVersionInitialized()) {
const auto currentVersion = serverGlobalParams.featureCompatibility.getVersion();
attrs.add("currentVersion", multiversion::toString(currentVersion));
isDifferent = currentVersion != newVersion;
}
if (isDifferent) {
attrs.add("newVersion", multiversion::toString(newVersion));
LOGV2(20459, "Setting featureCompatibilityVersion", attrs);
}
opCtx->recoveryUnit()->onCommit(
[opCtx, newVersion](boost::optional<Timestamp> ts) { _setVersion(opCtx, newVersion, ts); });
}
void FcvOpObserver::onInserts(OperationContext* opCtx,
const NamespaceString& nss,
const UUID& uuid,
std::vector<InsertStatement>::const_iterator first,
std::vector<InsertStatement>::const_iterator last,
bool fromMigrate) {
if (nss.isServerConfigurationCollection()) {
for (auto it = first; it != last; it++) {
_onInsertOrUpdate(opCtx, it->doc);
}
}
}
void FcvOpObserver::onUpdate(OperationContext* opCtx, const OplogUpdateEntryArgs& args) {
if (args.updateArgs->update.isEmpty()) {
return;
}
if (args.nss.isServerConfigurationCollection()) {
_onInsertOrUpdate(opCtx, args.updateArgs->updatedDoc);
}
}
void FcvOpObserver::onDelete(OperationContext* opCtx,
const NamespaceString& nss,
const UUID& uuid,
StmtId stmtId,
const OplogDeleteEntryArgs& args) {
// documentKeyDecoration is set in OpObserverImpl::aboutToDelete. So the FcvOpObserver
// relies on the OpObserverImpl also being in the opObserverRegistry.
auto optDocKey = repl::documentKeyDecoration(opCtx);
invariant(optDocKey, nss.ns());
if (nss.isServerConfigurationCollection()) {
auto id = optDocKey.get().getId().firstElement();
if (id.type() == BSONType::String && id.String() == multiversion::kParameterName) {
uasserted(40670, "removing FeatureCompatibilityVersion document is not allowed");
}
}
}
void FcvOpObserver::_onReplicationRollback(OperationContext* opCtx,
const RollbackObserverInfo& rbInfo) {
// Ensures the in-memory and on-disk FCV states are consistent after a rollback.
const auto query = BSON("_id" << multiversion::kParameterName);
const auto swFcv = repl::StorageInterface::get(opCtx)->findById(
opCtx, NamespaceString::kServerConfigurationNamespace, query["_id"]);
if (swFcv.isOK()) {
const auto featureCompatibilityVersion = swFcv.getValue();
auto swVersion = FeatureCompatibilityVersionParser::parse(featureCompatibilityVersion);
const auto memoryFcv = serverGlobalParams.featureCompatibility.getVersion();
if (swVersion.isOK() && (swVersion.getValue() != memoryFcv)) {
auto diskFcv = swVersion.getValue();
LOGV2(4675801,
"Setting featureCompatibilityVersion as part of rollback",
"newVersion"_attr = multiversion::toString(diskFcv),
"oldVersion"_attr = multiversion::toString(memoryFcv));
_setVersion(opCtx, diskFcv);
// The rollback FCV is already in the stable snapshot.
FeatureCompatibilityVersion::clearLastFCVUpdateTimestamp();
}
}
}
} // namespace mongo
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