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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.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kSharding
#include "mongo/db/auth/authorization_session.h"
#include "mongo/db/client.h"
#include "mongo/db/commands.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/repl/read_concern_args.h"
#include "mongo/db/repl/repl_client_info.h"
#include "mongo/db/s/config/sharding_catalog_manager.h"
#include "mongo/db/s/operation_sharding_state.h"
#include "mongo/s/catalog/dist_lock_manager.h"
#include "mongo/s/catalog/type_database.h"
#include "mongo/s/catalog_cache.h"
#include "mongo/s/client/shard_registry.h"
#include "mongo/s/cluster_commands_helpers.h"
#include "mongo/s/grid.h"
#include "mongo/s/stale_exception.h"
#include "mongo/util/fail_point_service.h"
#include "mongo/util/log.h"
#include "mongo/util/scopeguard.h"
namespace mongo {
namespace {
MONGO_FAIL_POINT_DEFINE(setDropCollDistLockWait);
template <typename F>
auto staleExceptionRetry(OperationContext* opCtx, StringData opStr, F&& f) {
uassert(ErrorCodes::IllegalOperation,
str::stream() << "Command " << opStr << " does not support database versioning",
!OperationShardingState::get(opCtx).hasDbVersion());
uassert(ErrorCodes::IllegalOperation,
str::stream() << "Command " << opStr << " does not support collection versioning",
!OperationShardingState::get(opCtx).hasShardVersion());
for (int tries = 0;; ++tries) {
// Try kMaxStaleExceptionTries times and on the last try, rethrow the exception
const bool canRetry = tries < kMaxNumStaleVersionRetries - 1;
try {
return f();
} catch (const ExceptionForCat<ErrorCategory::StaleShardVersionError>& ex) {
log() << "Attempt " << tries << " of " << opStr << " received StaleShardVersion error"
<< causedBy(ex);
if (canRetry) {
continue;
}
throw;
}
MONGO_UNREACHABLE;
}
}
/**
* Internal sharding command run on config servers to drop a collection from a database.
*/
class ConfigSvrDropCollectionCommand : public BasicCommand {
public:
ConfigSvrDropCollectionCommand() : BasicCommand("_configsvrDropCollection") {}
AllowedOnSecondary secondaryAllowed(ServiceContext*) const override {
return AllowedOnSecondary::kNever;
}
bool adminOnly() const override {
return true;
}
bool supportsWriteConcern(const BSONObj& cmd) const override {
return true;
}
std::string help() const override {
return "Internal command, which is exported by the sharding config server. Do not call "
"directly. Drops a collection from a database.";
}
Status checkAuthForCommand(Client* client,
const std::string& dbname,
const BSONObj& cmdObj) const override {
if (!AuthorizationSession::get(client)->isAuthorizedForActionsOnResource(
ResourcePattern::forClusterResource(), ActionType::internal)) {
return Status(ErrorCodes::Unauthorized, "Unauthorized");
}
return Status::OK();
}
std::string parseNs(const std::string& dbname, const BSONObj& cmdObj) const override {
return CommandHelpers::parseNsFullyQualified(cmdObj);
}
bool run(OperationContext* opCtx,
const std::string& dbname,
const BSONObj& cmdObj,
BSONObjBuilder& result) override {
uassert(ErrorCodes::IllegalOperation,
"_configsvrDropCollection can only be run on config servers",
serverGlobalParams.clusterRole == ClusterRole::ConfigServer);
// Set the operation context read concern level to local for reads into the config database.
repl::ReadConcernArgs::get(opCtx) =
repl::ReadConcernArgs(repl::ReadConcernLevel::kLocalReadConcern);
const NamespaceString nss(parseNs(dbname, cmdObj));
uassert(ErrorCodes::InvalidOptions,
str::stream() << "dropCollection must be called with majority writeConcern, got "
<< cmdObj,
opCtx->getWriteConcern().wMode == WriteConcernOptions::kMajority);
Seconds waitFor(DistLockManager::kDefaultLockTimeout);
MONGO_FAIL_POINT_BLOCK(setDropCollDistLockWait, customWait) {
const BSONObj& data = customWait.getData();
waitFor = Seconds(data["waitForSecs"].numberInt());
}
auto const catalogClient = Grid::get(opCtx)->catalogClient();
auto scopedDbLock =
ShardingCatalogManager::get(opCtx)->serializeCreateOrDropDatabase(opCtx, nss.db());
auto scopedCollLock =
ShardingCatalogManager::get(opCtx)->serializeCreateOrDropCollection(opCtx, nss);
auto dbDistLock = uassertStatusOK(
catalogClient->getDistLockManager()->lock(opCtx, nss.db(), "dropCollection", waitFor));
auto collDistLock = uassertStatusOK(
catalogClient->getDistLockManager()->lock(opCtx, nss.ns(), "dropCollection", waitFor));
ON_BLOCK_EXIT(
[opCtx, nss] { Grid::get(opCtx)->catalogCache()->invalidateShardedCollection(nss); });
staleExceptionRetry(
opCtx, "_configsvrDropCollection", [&] { _dropCollection(opCtx, nss); });
return true;
}
private:
static void _dropCollection(OperationContext* opCtx, const NamespaceString& nss) {
auto const catalogClient = Grid::get(opCtx)->catalogClient();
auto collStatus =
catalogClient->getCollection(opCtx, nss, repl::ReadConcernArgs::get(opCtx).getLevel());
if (collStatus == ErrorCodes::NamespaceNotFound) {
// We checked the sharding catalog and found that this collection doesn't exist. This
// may be because it never existed, or because a drop command was sent previously. This
// data might not be majority committed though, so we will set the client's last optime
// to the system's last optime to ensure the client waits for the writeConcern to be
// satisfied.
repl::ReplClientInfo::forClient(opCtx->getClient()).setLastOpToSystemLastOpTime(opCtx);
// If the DB isn't in the sharding catalog either, consider the drop a success.
auto dbStatus = catalogClient->getDatabase(
opCtx, nss.db().toString(), repl::ReadConcernArgs::get(opCtx).getLevel());
if (dbStatus == ErrorCodes::NamespaceNotFound) {
return;
}
uassertStatusOK(dbStatus);
// If we found the DB but not the collection, the collection might exist and not be
// sharded, so send the command to the primary shard.
_dropUnshardedCollectionFromShard(opCtx, dbStatus.getValue().value.getPrimary(), nss);
} else {
uassertStatusOK(collStatus);
uassertStatusOK(ShardingCatalogManager::get(opCtx)->dropCollection(opCtx, nss));
}
}
static void _dropUnshardedCollectionFromShard(OperationContext* opCtx,
const ShardId& shardId,
const NamespaceString& nss) {
const auto shardRegistry = Grid::get(opCtx)->shardRegistry();
const auto dropCommandBSON = [shardRegistry, opCtx, &shardId, &nss] {
BSONObjBuilder builder;
builder.append("drop", nss.coll());
// Append the chunk version for the specified namespace indicating that we believe it is
// not sharded. Collections residing on the config server are never sharded so do not
// send the shard version.
if (shardId != shardRegistry->getConfigShard()->getId()) {
ChunkVersion::UNSHARDED().appendToCommand(&builder);
}
if (!opCtx->getWriteConcern().usedDefault) {
builder.append(WriteConcernOptions::kWriteConcernField,
opCtx->getWriteConcern().toBSON());
}
return builder.obj();
}();
const auto shard = uassertStatusOK(shardRegistry->getShard(opCtx, shardId));
auto cmdDropResult = uassertStatusOK(shard->runCommandWithFixedRetryAttempts(
opCtx,
ReadPreferenceSetting{ReadPreference::PrimaryOnly},
nss.db().toString(),
dropCommandBSON,
Shard::RetryPolicy::kIdempotent));
// If the collection doesn't exist, consider the drop a success.
if (cmdDropResult.commandStatus == ErrorCodes::NamespaceNotFound) {
return;
}
uassertStatusOK(cmdDropResult.commandStatus);
uassertStatusOK(cmdDropResult.writeConcernStatus);
};
} configsvrDropCollectionCmd;
} // namespace
} // namespace mongo
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