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/**
* Copyright (C) 2016 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* 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 GNU Affero General 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.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kCommand
#include "mongo/platform/basic.h"
#include "mongo/db/commands/feature_compatibility_version.h"
#include "mongo/base/status.h"
#include "mongo/db/db_raii.h"
#include "mongo/db/dbdirectclient.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/repl/optime.h"
#include "mongo/db/repl/storage_interface.h"
#include "mongo/db/server_parameters.h"
#include "mongo/db/service_context.h"
#include "mongo/db/storage/storage_engine.h"
#include "mongo/db/write_concern_options.h"
#include "mongo/rpc/get_status_from_command_result.h"
#include "mongo/transport/service_entry_point.h"
#include "mongo/util/log.h"
namespace mongo {
using repl::UnreplicatedWritesBlock;
constexpr StringData FeatureCompatibilityVersion::kCollection;
constexpr StringData FeatureCompatibilityVersion::kCommandName;
constexpr StringData FeatureCompatibilityVersion::kDatabase;
constexpr StringData FeatureCompatibilityVersion::kParameterName;
constexpr StringData FeatureCompatibilityVersion::kVersionField;
constexpr StringData FeatureCompatibilityVersion::kTargetVersionField;
Lock::ResourceMutex FeatureCompatibilityVersion::fcvLock("featureCompatibilityVersionLock");
StatusWith<ServerGlobalParams::FeatureCompatibility::Version> FeatureCompatibilityVersion::parse(
const BSONObj& featureCompatibilityVersionDoc) {
ServerGlobalParams::FeatureCompatibility::Version version =
ServerGlobalParams::FeatureCompatibility::Version::kUnsetDefault34Behavior;
std::string versionString;
std::string targetVersionString;
for (auto&& elem : featureCompatibilityVersionDoc) {
auto fieldName = elem.fieldNameStringData();
if (fieldName == "_id") {
continue;
} else if (fieldName == FeatureCompatibilityVersion::kVersionField ||
fieldName == FeatureCompatibilityVersion::kTargetVersionField) {
if (elem.type() != BSONType::String) {
return Status(ErrorCodes::TypeMismatch,
str::stream() << fieldName
<< " must be of type String, but was of type "
<< typeName(elem.type())
<< ". Contents of "
<< FeatureCompatibilityVersion::kParameterName
<< " document in "
<< FeatureCompatibilityVersion::kCollection
<< ": "
<< featureCompatibilityVersionDoc
<< ". See "
<< feature_compatibility_version::kDochubLink
<< ".");
}
if (elem.String() != FeatureCompatibilityVersionCommandParser::kVersion36 &&
elem.String() != FeatureCompatibilityVersionCommandParser::kVersion34) {
return Status(ErrorCodes::BadValue,
str::stream() << "Invalid value for " << fieldName << ", found "
<< elem.String()
<< ", expected '"
<< FeatureCompatibilityVersionCommandParser::kVersion36
<< "' or '"
<< FeatureCompatibilityVersionCommandParser::kVersion34
<< "'. Contents of "
<< FeatureCompatibilityVersion::kParameterName
<< " document in "
<< FeatureCompatibilityVersion::kCollection
<< ": "
<< featureCompatibilityVersionDoc
<< ". See "
<< feature_compatibility_version::kDochubLink
<< ".");
}
if (fieldName == FeatureCompatibilityVersion::kVersionField) {
versionString = elem.String();
} else if (fieldName == FeatureCompatibilityVersion::kTargetVersionField) {
targetVersionString = elem.String();
}
} else {
return Status(ErrorCodes::BadValue,
str::stream() << "Unrecognized field '" << fieldName << "'. Contents of "
<< FeatureCompatibilityVersion::kParameterName
<< " document in "
<< FeatureCompatibilityVersion::kCollection
<< ": "
<< featureCompatibilityVersionDoc
<< ". See "
<< feature_compatibility_version::kDochubLink
<< ".");
}
}
if (versionString == FeatureCompatibilityVersionCommandParser::kVersion34) {
if (targetVersionString == FeatureCompatibilityVersionCommandParser::kVersion36) {
version = ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo36;
} else if (targetVersionString == FeatureCompatibilityVersionCommandParser::kVersion34) {
version = ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo34;
} else {
version = ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo34;
}
} else if (versionString == FeatureCompatibilityVersionCommandParser::kVersion36) {
if (targetVersionString == FeatureCompatibilityVersionCommandParser::kVersion36 ||
targetVersionString == FeatureCompatibilityVersionCommandParser::kVersion34) {
return Status(ErrorCodes::BadValue,
str::stream() << "Invalid state for "
<< FeatureCompatibilityVersion::kParameterName
<< " document in "
<< FeatureCompatibilityVersion::kCollection
<< ": "
<< featureCompatibilityVersionDoc
<< ". See "
<< feature_compatibility_version::kDochubLink
<< ".");
} else {
version = ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo36;
}
} else {
return Status(ErrorCodes::BadValue,
str::stream() << "Missing required field '"
<< FeatureCompatibilityVersion::kVersionField
<< "''. Contents of "
<< FeatureCompatibilityVersion::kParameterName
<< " document in "
<< FeatureCompatibilityVersion::kCollection
<< ": "
<< featureCompatibilityVersionDoc
<< ". See "
<< feature_compatibility_version::kDochubLink
<< ".");
}
return version;
}
void FeatureCompatibilityVersion::setTargetUpgrade(OperationContext* opCtx) {
// Sets both 'version' and 'targetVersion' fields.
_runUpdateCommand(opCtx, [](auto updateMods) {
updateMods.append(FeatureCompatibilityVersion::kVersionField,
FeatureCompatibilityVersionCommandParser::kVersion34);
updateMods.append(FeatureCompatibilityVersion::kTargetVersionField,
FeatureCompatibilityVersionCommandParser::kVersion36);
});
}
void FeatureCompatibilityVersion::setTargetDowngrade(OperationContext* opCtx) {
// Sets both 'version' and 'targetVersion' fields.
_runUpdateCommand(opCtx, [](auto updateMods) {
updateMods.append(FeatureCompatibilityVersion::kVersionField,
FeatureCompatibilityVersionCommandParser::kVersion34);
updateMods.append(FeatureCompatibilityVersion::kTargetVersionField,
FeatureCompatibilityVersionCommandParser::kVersion34);
});
}
void FeatureCompatibilityVersion::unsetTargetUpgradeOrDowngrade(OperationContext* opCtx,
StringData version) {
_validateVersion(version);
// Updates 'version' field, while also unsetting the 'targetVersion' field.
_runUpdateCommand(opCtx, [version](auto updateMods) {
updateMods.append(FeatureCompatibilityVersion::kVersionField, version);
});
}
void FeatureCompatibilityVersion::setIfCleanStartup(OperationContext* opCtx,
repl::StorageInterface* storageInterface) {
// A clean startup means there are no databases on disk besides the local database.
std::vector<std::string> dbNames;
StorageEngine* storageEngine = getGlobalServiceContext()->getGlobalStorageEngine();
storageEngine->listDatabases(&dbNames);
for (auto&& dbName : dbNames) {
if (dbName != "local") {
return;
}
}
// If the server was not started with --shardsvr, the default featureCompatibilityVersion on
// clean startup is the upgrade version. If it was started with --shardsvr, the default
// featureCompatibilityVersion is the downgrade version, so that it can be safely added to a
// downgrade version cluster. The config server will run setFeatureCompatibilityVersion as part
// of addShard.
const bool storeUpgradeVersion = serverGlobalParams.clusterRole != ClusterRole::ShardServer;
UnreplicatedWritesBlock unreplicatedWritesBlock(opCtx);
NamespaceString nss(FeatureCompatibilityVersion::kCollection);
{
AutoGetOrCreateDb autoDB(opCtx, nss.db(), MODE_X);
// We reached this point because the only database that exists on the server is "local"
// and we have just created an empty "admin" database. Therefore, it is safe to create
// the "admin.system.version" collection.
invariant(autoDB.justCreated());
if (storeUpgradeVersion) {
// We update the value of the version server parameter so that the admin.system.version
// collection gets a UUID.
serverGlobalParams.featureCompatibility.setVersion(
ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo36);
}
uassertStatusOK(storageInterface->createCollection(opCtx, nss, {}));
}
// We then insert the featureCompatibilityVersion document into the "admin.system.version"
// collection. The server parameter will be updated on commit by the op observer.
uassertStatusOK(storageInterface->insertDocument(
opCtx,
nss,
repl::TimestampedBSONObj{
BSON("_id" << FeatureCompatibilityVersion::kParameterName
<< FeatureCompatibilityVersion::kVersionField
<< (storeUpgradeVersion
? FeatureCompatibilityVersionCommandParser::kVersion36
: FeatureCompatibilityVersionCommandParser::kVersion34)),
SnapshotName()},
repl::OpTime::kUninitializedTerm)); // No timestamp or term because this write is not
// replicated.
}
namespace {
// If a node finishes rollback while in fcv=3.6, but while in RECOVERING before reaching
// minValid, sees that its sync source started a downgrade to fcv=3.4, it may be be unable to
// become consistent. This is because an fcv=3.6 node will have used the UUID algorithm for
// rollback, which treats a missing UUID as a collection drop. We fassert before becoming
// SECONDARY in an inconsistent state.
//
// We only care about the start of downgrade, because if we see an oplog entry marking the end
// of downgrade, then either we also saw a downgrade start op, or we did our rollback in fcv=3.4
// with the no-UUID algorithm. Similarly, we do not care about upgrade, because either
// it will also have a downgrade op, or we did our rollback in fcv=3.4. The no-UUID rollback
// algorithm will be as safe as it was in 3.4 regardless of if the sync source has UUIDs or not.
void uassertDuringRollbackOnDowngradeOp(
OperationContext* opCtx,
ServerGlobalParams::FeatureCompatibility::Version newVersion,
std::string msg) {
if ((newVersion != ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo34) ||
(serverGlobalParams.featureCompatibility.getVersion() !=
ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo36)) {
// This is only the start of a downgrade operation if we're currently upgraded to 3.6.
return;
}
auto replCoord = repl::ReplicationCoordinator::get(opCtx);
uassert(ErrorCodes::OplogOperationUnsupported,
msg,
replCoord->getReplicationMode() != repl::ReplicationCoordinator::modeReplSet ||
replCoord->isInPrimaryOrSecondaryState());
}
// If we are finishing an upgrade, all collections should have UUIDs. We check to make sure
// that the feature compatibility version collection has a UUID.
void uassertDuringInvalidUpgradeOp(OperationContext* opCtx,
ServerGlobalParams::FeatureCompatibility::Version version) {
auto replCoord = repl::ReplicationCoordinator::get(opCtx);
if (replCoord->getReplicationMode() == repl::ReplicationCoordinator::modeMasterSlave) {
// TODO (SERVER-31593) master-slave should uassert here, but cannot due to a bug.
return;
}
if (version != ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo36) {
// Only check this assertion if we're completing an upgrade to 3.6.
return;
}
auto fcvUUID = repl::StorageInterface::get(opCtx)->getCollectionUUID(
opCtx, NamespaceString(FeatureCompatibilityVersion::kCollection));
uassert(ErrorCodes::IllegalOperation,
str::stream() << "Error checking for UUID in feature compatibility version collection: "
<< fcvUUID.getStatus().toString(),
fcvUUID.isOK());
uassert(ErrorCodes::IllegalOperation,
str::stream() << "Tried to complete upgrade, but "
<< FeatureCompatibilityVersion::kCollection
<< " did not have a UUID.",
fcvUUID.getValue());
}
} // namespace
void FeatureCompatibilityVersion::onInsertOrUpdate(OperationContext* opCtx, const BSONObj& doc) {
auto idElement = doc["_id"];
if (idElement.type() != BSONType::String ||
idElement.String() != FeatureCompatibilityVersion::kParameterName) {
return;
}
auto newVersion = uassertStatusOK(FeatureCompatibilityVersion::parse(doc));
uassertDuringRollbackOnDowngradeOp(opCtx,
newVersion,
str::stream()
<< "Must be in primary or secondary state to "
"downgrade feature compatibility version document: "
<< redact(doc));
uassertDuringInvalidUpgradeOp(opCtx, newVersion);
// To avoid extra log messages when the targetVersion is set/unset, only log when the version
// changes.
auto oldVersion = serverGlobalParams.featureCompatibility.getVersion();
if (oldVersion != newVersion) {
log() << "setting featureCompatibilityVersion to " << toString(newVersion);
}
// On commit, update the server parameters, and close any incoming connections with a wire
// version that is below the minimum.
opCtx->recoveryUnit()->onCommit([opCtx, newVersion]() {
serverGlobalParams.featureCompatibility.setVersion(newVersion);
// Close all connections from internal clients with binary versions lower than 3.6.
if (newVersion == ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo36 ||
newVersion == ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo36) {
opCtx->getServiceContext()->getServiceEntryPoint()->endAllSessions(
transport::Session::kLatestVersionInternalClientKeepOpen |
transport::Session::kExternalClientKeepOpen);
}
});
}
void FeatureCompatibilityVersion::onDelete(OperationContext* opCtx, const BSONObj& doc) {
auto idElement = doc["_id"];
if (idElement.type() != BSONType::String ||
idElement.String() != FeatureCompatibilityVersion::kParameterName) {
return;
}
uassertDuringRollbackOnDowngradeOp(
opCtx,
ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo34,
"Must be in primary or secondary state to delete feature compatibility version document");
log() << "setting featureCompatibilityVersion to "
<< FeatureCompatibilityVersionCommandParser::kVersion34;
opCtx->recoveryUnit()->onCommit([]() {
serverGlobalParams.featureCompatibility.setVersion(
ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo34);
});
}
void FeatureCompatibilityVersion::onDropCollection(OperationContext* opCtx) {
uassertDuringRollbackOnDowngradeOp(
opCtx,
ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo34,
str::stream() << "Must be in primary or secondary state to drop "
<< FeatureCompatibilityVersion::kCollection
<< " collection");
log() << "setting featureCompatibilityVersion to "
<< FeatureCompatibilityVersionCommandParser::kVersion34;
opCtx->recoveryUnit()->onCommit([]() {
serverGlobalParams.featureCompatibility.setVersion(
ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo34);
});
}
void FeatureCompatibilityVersion::_validateVersion(StringData version) {
uassert(40284,
str::stream() << "featureCompatibilityVersion must be '"
<< FeatureCompatibilityVersionCommandParser::kVersion36
<< "' or '"
<< FeatureCompatibilityVersionCommandParser::kVersion34
<< "'. See "
<< feature_compatibility_version::kDochubLink
<< ".",
version == FeatureCompatibilityVersionCommandParser::kVersion36 ||
version == FeatureCompatibilityVersionCommandParser::kVersion34);
}
void FeatureCompatibilityVersion::_runUpdateCommand(OperationContext* opCtx,
UpdateBuilder builder) {
DBDirectClient client(opCtx);
NamespaceString nss(FeatureCompatibilityVersion::kCollection);
BSONObjBuilder updateCmd;
updateCmd.append("update", nss.coll());
{
BSONArrayBuilder updates(updateCmd.subarrayStart("updates"));
{
BSONObjBuilder updateSpec(updates.subobjStart());
{
BSONObjBuilder queryFilter(updateSpec.subobjStart("q"));
queryFilter.append("_id", FeatureCompatibilityVersion::kParameterName);
}
{
BSONObjBuilder updateMods(updateSpec.subobjStart("u"));
builder(std::move(updateMods));
}
updateSpec.appendBool("upsert", true);
}
}
updateCmd.append(WriteConcernOptions::kWriteConcernField, WriteConcernOptions::Majority);
// Update the featureCompatibilityVersion document stored in the "admin.system.version"
// collection.
BSONObj updateResult;
client.runCommand(nss.db().toString(), updateCmd.obj(), updateResult);
uassertStatusOK(getStatusFromWriteCommandReply(updateResult));
}
/**
* Read-only server parameter for featureCompatibilityVersion.
*/
class FeatureCompatibilityVersionParameter : public ServerParameter {
public:
FeatureCompatibilityVersionParameter()
: ServerParameter(ServerParameterSet::getGlobal(),
FeatureCompatibilityVersion::kParameterName.toString(),
false, // allowedToChangeAtStartup
false // allowedToChangeAtRuntime
) {}
virtual void append(OperationContext* opCtx, BSONObjBuilder& b, const std::string& name) {
BSONObjBuilder featureCompatibilityVersionBuilder(b.subobjStart(name));
switch (serverGlobalParams.featureCompatibility.getVersion()) {
case ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo36:
featureCompatibilityVersionBuilder.append(
FeatureCompatibilityVersion::kVersionField,
FeatureCompatibilityVersionCommandParser::kVersion36);
return;
case ServerGlobalParams::FeatureCompatibility::Version::kFullyDowngradedTo34:
featureCompatibilityVersionBuilder.append(
FeatureCompatibilityVersion::kVersionField,
FeatureCompatibilityVersionCommandParser::kVersion34);
return;
case ServerGlobalParams::FeatureCompatibility::Version::kUpgradingTo36:
featureCompatibilityVersionBuilder.append(
FeatureCompatibilityVersion::kVersionField,
FeatureCompatibilityVersionCommandParser::kVersion34);
featureCompatibilityVersionBuilder.append(
FeatureCompatibilityVersion::kTargetVersionField,
FeatureCompatibilityVersionCommandParser::kVersion36);
return;
case ServerGlobalParams::FeatureCompatibility::Version::kDowngradingTo34:
featureCompatibilityVersionBuilder.append(
FeatureCompatibilityVersion::kVersionField,
FeatureCompatibilityVersionCommandParser::kVersion34);
featureCompatibilityVersionBuilder.append(
FeatureCompatibilityVersion::kTargetVersionField,
FeatureCompatibilityVersionCommandParser::kVersion34);
return;
default:
MONGO_UNREACHABLE;
}
}
virtual Status set(const BSONElement& newValueElement) {
return Status(ErrorCodes::IllegalOperation,
str::stream() << FeatureCompatibilityVersion::kParameterName
<< " cannot be set via setParameter. See "
<< feature_compatibility_version::kDochubLink
<< ".");
}
virtual Status setFromString(const std::string& str) {
return Status(ErrorCodes::IllegalOperation,
str::stream() << FeatureCompatibilityVersion::kParameterName
<< " cannot be set via setParameter. See "
<< feature_compatibility_version::kDochubLink
<< ".");
}
} featureCompatibilityVersionParameter;
MONGO_EXPORT_STARTUP_SERVER_PARAMETER(internalValidateFeaturesAsMaster, bool, true);
} // namespace mongo
|