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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.
*/
#include "mongo/platform/basic.h"
#include "mongo/db/s/active_migrations_registry.h"
#include "mongo/base/status_with.h"
#include "mongo/db/catalog/catalog_raii.h"
#include "mongo/db/s/collection_sharding_state.h"
#include "mongo/db/s/migration_session_id.h"
#include "mongo/db/s/migration_source_manager.h"
#include "mongo/util/assert_util.h"
namespace mongo {
ActiveMigrationsRegistry::ActiveMigrationsRegistry() = default;
ActiveMigrationsRegistry::~ActiveMigrationsRegistry() {
invariant(!_activeMoveChunkState);
}
StatusWith<ScopedDonateChunk> ActiveMigrationsRegistry::registerDonateChunk(
const MoveChunkRequest& args) {
stdx::lock_guard<stdx::mutex> lk(_mutex);
if (_activeReceiveChunkState) {
return _activeReceiveChunkState->constructErrorStatus();
}
if (_activeMoveChunkState) {
if (_activeMoveChunkState->args == args) {
return {ScopedDonateChunk(nullptr, false, _activeMoveChunkState->notification)};
}
return _activeMoveChunkState->constructErrorStatus();
}
_activeMoveChunkState.emplace(args);
return {ScopedDonateChunk(this, true, _activeMoveChunkState->notification)};
}
StatusWith<ScopedReceiveChunk> ActiveMigrationsRegistry::registerReceiveChunk(
const NamespaceString& nss, const ChunkRange& chunkRange, const ShardId& fromShardId) {
stdx::lock_guard<stdx::mutex> lk(_mutex);
if (_activeReceiveChunkState) {
return _activeReceiveChunkState->constructErrorStatus();
}
if (_activeMoveChunkState) {
return _activeMoveChunkState->constructErrorStatus();
}
_activeReceiveChunkState.emplace(nss, chunkRange, fromShardId);
return {ScopedReceiveChunk(this)};
}
boost::optional<NamespaceString> ActiveMigrationsRegistry::getActiveDonateChunkNss() {
stdx::lock_guard<stdx::mutex> lk(_mutex);
if (_activeMoveChunkState) {
return _activeMoveChunkState->args.getNss();
}
return boost::none;
}
BSONObj ActiveMigrationsRegistry::getActiveMigrationStatusReport(OperationContext* opCtx) {
boost::optional<NamespaceString> nss;
{
stdx::lock_guard<stdx::mutex> lk(_mutex);
if (_activeMoveChunkState) {
nss = _activeMoveChunkState->args.getNss();
}
}
// The state of the MigrationSourceManager could change between taking and releasing the mutex
// above and then taking the collection lock here, but that's fine because it isn't important to
// return information on a migration that just ended or started. This is just best effort and
// desireable for reporting, and then diagnosing, migrations that are stuck.
if (nss) {
// Lock the collection so nothing changes while we're getting the migration report.
AutoGetCollection autoColl(opCtx, nss.get(), MODE_IS);
auto css = CollectionShardingState::get(opCtx, nss.get());
if (css->getMigrationSourceManager()) {
return css->getMigrationSourceManager()->getMigrationStatusReport();
}
}
return BSONObj();
}
void ActiveMigrationsRegistry::_clearDonateChunk() {
stdx::lock_guard<stdx::mutex> lk(_mutex);
invariant(_activeMoveChunkState);
_activeMoveChunkState.reset();
}
void ActiveMigrationsRegistry::_clearReceiveChunk() {
stdx::lock_guard<stdx::mutex> lk(_mutex);
invariant(_activeReceiveChunkState);
_activeReceiveChunkState.reset();
}
Status ActiveMigrationsRegistry::ActiveMoveChunkState::constructErrorStatus() const {
return {ErrorCodes::ConflictingOperationInProgress,
str::stream() << "Unable to start new migration because this shard is currently "
"donating chunk "
<< ChunkRange(args.getMinKey(), args.getMaxKey()).toString()
<< " for namespace "
<< args.getNss().ns()
<< " to "
<< args.getToShardId()};
}
Status ActiveMigrationsRegistry::ActiveReceiveChunkState::constructErrorStatus() const {
return {ErrorCodes::ConflictingOperationInProgress,
str::stream() << "Unable to start new migration because this shard is currently "
"receiving chunk "
<< range.toString()
<< " for namespace "
<< nss.ns()
<< " from "
<< fromShardId};
}
ScopedDonateChunk::ScopedDonateChunk(ActiveMigrationsRegistry* registry,
bool shouldExecute,
std::shared_ptr<Notification<Status>> completionNotification)
: _registry(registry),
_shouldExecute(shouldExecute),
_completionNotification(std::move(completionNotification)) {}
ScopedDonateChunk::~ScopedDonateChunk() {
if (_registry && _shouldExecute) {
// If this is a newly started migration the caller must always signal on completion
invariant(*_completionNotification);
_registry->_clearDonateChunk();
}
}
ScopedDonateChunk::ScopedDonateChunk(ScopedDonateChunk&& other) {
*this = std::move(other);
}
ScopedDonateChunk& ScopedDonateChunk::operator=(ScopedDonateChunk&& other) {
if (&other != this) {
_registry = other._registry;
other._registry = nullptr;
_shouldExecute = other._shouldExecute;
_completionNotification = std::move(other._completionNotification);
}
return *this;
}
void ScopedDonateChunk::signalComplete(Status status) {
invariant(_shouldExecute);
_completionNotification->set(status);
}
Status ScopedDonateChunk::waitForCompletion(OperationContext* opCtx) {
invariant(!_shouldExecute);
return _completionNotification->get(opCtx);
}
ScopedReceiveChunk::ScopedReceiveChunk(ActiveMigrationsRegistry* registry) : _registry(registry) {}
ScopedReceiveChunk::~ScopedReceiveChunk() {
if (_registry) {
_registry->_clearReceiveChunk();
}
}
ScopedReceiveChunk::ScopedReceiveChunk(ScopedReceiveChunk&& other) {
*this = std::move(other);
}
ScopedReceiveChunk& ScopedReceiveChunk::operator=(ScopedReceiveChunk&& other) {
if (&other != this) {
_registry = other._registry;
other._registry = nullptr;
}
return *this;
}
} // namespace mongo
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