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/**
* Copyright (C) 2018-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/s/database_sharding_state.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/s/operation_sharding_state.h"
#include "mongo/logv2/log.h"
#include "mongo/stdx/unordered_map.h"
#include "mongo/util/fail_point.h"
#define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kSharding
namespace mongo {
namespace {
class DatabaseShardingStateMap {
DatabaseShardingStateMap& operator=(const DatabaseShardingStateMap&) = delete;
DatabaseShardingStateMap(const DatabaseShardingStateMap&) = delete;
public:
static const ServiceContext::Decoration<DatabaseShardingStateMap> get;
DatabaseShardingStateMap() {}
struct DSSAndLock {
DSSAndLock(const DatabaseName& dbName)
: dssMutex("DSSMutex::" + dbName.db()),
dss(std::make_unique<DatabaseShardingState>(dbName)) {}
const Lock::ResourceMutex dssMutex;
std::unique_ptr<DatabaseShardingState> dss;
};
DSSAndLock* getOrCreate(const DatabaseName& dbName) {
stdx::lock_guard<Latch> lg(_mutex);
auto it = _databases.find(dbName);
if (it == _databases.end()) {
auto inserted = _databases.try_emplace(dbName, std::make_unique<DSSAndLock>(dbName));
invariant(inserted.second);
it = std::move(inserted.first);
}
return it->second.get();
}
std::vector<DatabaseName> getDatabaseNames() {
stdx::lock_guard lg(_mutex);
std::vector<DatabaseName> result;
result.reserve(_databases.size());
for (const auto& [dbName, _] : _databases) {
result.emplace_back(dbName);
}
return result;
}
private:
Mutex _mutex = MONGO_MAKE_LATCH("DatabaseShardingStateMap::_mutex");
// Entries of the _databases map must never be deleted or replaced. This is to guarantee that a
// 'dbName' is always associated to the same 'ResourceMutex'.
using DatabasesMap = stdx::unordered_map<DatabaseName, std::unique_ptr<DSSAndLock>>;
DatabasesMap _databases;
};
const ServiceContext::Decoration<DatabaseShardingStateMap> DatabaseShardingStateMap::get =
ServiceContext::declareDecoration<DatabaseShardingStateMap>();
} // namespace
DatabaseShardingState::ScopedDatabaseShardingState::ScopedDatabaseShardingState(
Lock::ResourceLock lock, DatabaseShardingState* dss)
: _lock(std::move(lock)), _dss(dss) {}
DatabaseShardingState::ScopedDatabaseShardingState::ScopedDatabaseShardingState(
ScopedDatabaseShardingState&& other)
: _lock(std::move(other._lock)), _dss(other._dss) {
other._dss = nullptr;
}
DatabaseShardingState::ScopedDatabaseShardingState::~ScopedDatabaseShardingState() = default;
DatabaseShardingState::DatabaseShardingState(const DatabaseName& dbName) : _dbName(dbName) {}
DatabaseShardingState::ScopedDatabaseShardingState DatabaseShardingState::assertDbLockedAndAcquire(
OperationContext* opCtx, const DatabaseName& dbName, DSSAcquisitionMode mode) {
dassert(opCtx->lockState()->isDbLockedForMode(dbName, MODE_IS));
return acquire(opCtx, dbName, mode);
}
DatabaseShardingState::ScopedDatabaseShardingState DatabaseShardingState::acquire(
OperationContext* opCtx, const DatabaseName& dbName, DSSAcquisitionMode mode) {
DatabaseShardingStateMap::DSSAndLock* dssAndLock =
DatabaseShardingStateMap::get(opCtx->getServiceContext()).getOrCreate(dbName);
// First lock the RESOURCE_MUTEX associated to this dbName to guarantee stability of the
// DatabaseShardingState pointer. After that, it is safe to get and store the
// DatabaseShadingState*, as long as the RESOURCE_MUTEX is kept locked.
Lock::ResourceLock lock(opCtx->lockState(),
dssAndLock->dssMutex.getRid(),
mode == DSSAcquisitionMode::kShared ? MODE_IS : MODE_X);
return ScopedDatabaseShardingState(std::move(lock), dssAndLock->dss.get());
}
std::vector<DatabaseName> DatabaseShardingState::getDatabaseNames(OperationContext* opCtx) {
auto& databasesMap = DatabaseShardingStateMap::get(opCtx->getServiceContext());
return databasesMap.getDatabaseNames();
}
void DatabaseShardingState::enterCriticalSectionCatchUpPhase(OperationContext* opCtx,
const BSONObj& reason) {
_critSec.enterCriticalSectionCatchUpPhase(reason);
cancelDbMetadataRefresh();
}
void DatabaseShardingState::enterCriticalSectionCommitPhase(OperationContext* opCtx,
const BSONObj& reason) {
_critSec.enterCriticalSectionCommitPhase(reason);
}
void DatabaseShardingState::exitCriticalSection(OperationContext* opCtx, const BSONObj& reason) {
_critSec.exitCriticalSection(reason);
}
void DatabaseShardingState::exitCriticalSectionNoChecks(OperationContext* opCtx) {
_critSec.exitCriticalSectionNoChecks();
}
void DatabaseShardingState::setMovePrimarySourceManager(OperationContext* opCtx,
MovePrimarySourceManager* sourceMgr) {
invariant(opCtx->lockState()->isDbLockedForMode(_dbName, MODE_X));
invariant(sourceMgr);
invariant(!_sourceMgr);
_sourceMgr = sourceMgr;
}
void DatabaseShardingState::clearMovePrimarySourceManager(OperationContext* opCtx) {
invariant(opCtx->lockState()->isDbLockedForMode(_dbName, MODE_IX));
_sourceMgr = nullptr;
}
void DatabaseShardingState::setDbMetadataRefreshFuture(SharedSemiFuture<void> future,
CancellationSource cancellationSource) {
invariant(!_dbMetadataRefresh);
_dbMetadataRefresh.emplace(std::move(future), std::move(cancellationSource));
}
boost::optional<SharedSemiFuture<void>> DatabaseShardingState::getDbMetadataRefreshFuture() const {
return _dbMetadataRefresh ? boost::optional<SharedSemiFuture<void>>(_dbMetadataRefresh->future)
: boost::none;
}
void DatabaseShardingState::resetDbMetadataRefreshFuture() {
_dbMetadataRefresh = boost::none;
}
void DatabaseShardingState::cancelDbMetadataRefresh() {
if (_dbMetadataRefresh) {
_dbMetadataRefresh->cancellationSource.cancel();
}
}
} // namespace mongo
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