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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/platform/basic.h"
#include "mongo/db/catalog_raii.h"
#include "mongo/db/catalog/collection_catalog.h"
#include "mongo/db/catalog/database_holder.h"
#include "mongo/db/s/database_sharding_state.h"
#include "mongo/db/views/view_catalog.h"
#include "mongo/util/fail_point_service.h"
namespace mongo {
namespace {
MONGO_FAIL_POINT_DEFINE(setAutoGetCollectionWait);
} // namespace
AutoGetDb::AutoGetDb(OperationContext* opCtx, StringData dbName, LockMode mode, Date_t deadline)
: _dbLock(opCtx, dbName, mode, deadline), _db([&] {
auto databaseHolder = DatabaseHolder::get(opCtx);
return databaseHolder->getDb(opCtx, dbName);
}()) {
if (_db) {
auto& dss = DatabaseShardingState::get(_db);
auto dssLock = DatabaseShardingState::DSSLock::lockShared(opCtx, &dss);
dss.checkDbVersion(opCtx, dssLock);
}
}
AutoGetCollection::AutoGetCollection(OperationContext* opCtx,
const NamespaceStringOrUUID& nsOrUUID,
LockMode modeDB,
LockMode modeColl,
ViewMode viewMode,
Date_t deadline)
: _autoDb(opCtx,
!nsOrUUID.dbname().empty() ? nsOrUUID.dbname() : nsOrUUID.nss()->db(),
modeDB,
deadline),
_resolvedNss(resolveNamespaceStringOrUUID(opCtx, nsOrUUID)) {
NamespaceString prevResolvedNss;
do {
_collLock.emplace(opCtx, _resolvedNss, modeColl, deadline);
// We looked up nsOrUUID without a collection lock so it's possible that the
// collection is dropped now. Look it up again.
prevResolvedNss = _resolvedNss;
_resolvedNss = resolveNamespaceStringOrUUID(opCtx, nsOrUUID);
} while (_resolvedNss != prevResolvedNss);
// Wait for a configured amount of time after acquiring locks if the failpoint is enabled
MONGO_FAIL_POINT_BLOCK(setAutoGetCollectionWait, customWait) {
const BSONObj& data = customWait.getData();
sleepFor(Milliseconds(data["waitForMillis"].numberInt()));
}
Database* const db = _autoDb.getDb();
invariant(!nsOrUUID.uuid() || db,
str::stream() << "Database for " << _resolvedNss.ns()
<< " disappeared after successufully resolving "
<< nsOrUUID.toString());
// In most cases we expect modifications for system.views to upgrade MODE_IX to MODE_X before
// taking the lock. One exception is a query by UUID of system.views in a transaction. Usual
// queries of system.views (by name, not UUID) within a transaction are rejected. However, if
// the query is by UUID we can't determine whether the namespace is actually system.views until
// we take the lock here. So we have this one last assertion.
uassert(51070,
"Modifications to system.views must take an exclusive lock",
!_resolvedNss.isSystemDotViews() || modeColl != MODE_IX);
// If the database doesn't exists, we can't obtain a collection or check for views
if (!db)
return;
_coll = db->getCollection(opCtx, _resolvedNss);
invariant(!nsOrUUID.uuid() || _coll,
str::stream() << "Collection for " << _resolvedNss.ns()
<< " disappeared after successufully resolving "
<< nsOrUUID.toString());
if (_coll) {
// Unlike read concern majority, read concern snapshot cannot yield and wait when there are
// pending catalog changes. Instead, we must return an error in such situations. We ignore
// this restriction for the oplog, since it never has pending catalog changes.
auto readConcernLevel = repl::ReadConcernArgs::get(opCtx).getLevel();
if (readConcernLevel == repl::ReadConcernLevel::kSnapshotReadConcern &&
_resolvedNss != NamespaceString::kRsOplogNamespace) {
auto mySnapshot = opCtx->recoveryUnit()->getPointInTimeReadTimestamp();
if (mySnapshot) {
auto minSnapshot = _coll->getMinimumVisibleSnapshot();
uassert(ErrorCodes::SnapshotUnavailable,
str::stream()
<< "Unable to read from a snapshot due to pending collection catalog "
"changes; please retry the operation. Snapshot timestamp is "
<< mySnapshot->toString() << ". Collection minimum is "
<< minSnapshot->toString(),
!minSnapshot || *mySnapshot >= *minSnapshot);
}
}
// If the collection exists, there is no need to check for views.
return;
}
_view = ViewCatalog::get(db)->lookup(opCtx, _resolvedNss.ns());
uassert(ErrorCodes::CommandNotSupportedOnView,
str::stream() << "Namespace " << _resolvedNss.ns() << " is a view, not a collection",
!_view || viewMode == kViewsPermitted);
}
NamespaceString AutoGetCollection::resolveNamespaceStringOrUUID(OperationContext* opCtx,
NamespaceStringOrUUID nsOrUUID) {
if (auto& nss = nsOrUUID.nss()) {
uassert(ErrorCodes::InvalidNamespace,
str::stream() << "Namespace " << *nss << " is not a valid collection name",
nss->isValid());
return *nss;
}
CollectionCatalog& catalog = CollectionCatalog::get(opCtx);
auto resolvedNss = catalog.lookupNSSByUUID(*nsOrUUID.uuid());
uassert(ErrorCodes::NamespaceNotFound,
str::stream() << "Unable to resolve " << nsOrUUID.toString(),
resolvedNss && resolvedNss->isValid());
uassert(ErrorCodes::NamespaceNotFound,
str::stream() << "UUID " << nsOrUUID.toString() << " specified in " << nsOrUUID.dbname()
<< " resolved to a collection in a different database: " << *resolvedNss,
resolvedNss->db() == nsOrUUID.dbname());
return *resolvedNss;
}
AutoGetOrCreateDb::AutoGetOrCreateDb(OperationContext* opCtx,
StringData dbName,
LockMode mode,
Date_t deadline) {
invariant(mode == MODE_IX || mode == MODE_X);
_autoDb.emplace(opCtx, dbName, mode, deadline);
_db = _autoDb->getDb();
// If the database didn't exist, relock in MODE_X
if (!_db) {
if (mode != MODE_X) {
_autoDb.emplace(opCtx, dbName, MODE_X, deadline);
}
auto databaseHolder = DatabaseHolder::get(opCtx);
_db = databaseHolder->openDb(opCtx, dbName, &_justCreated);
}
auto& dss = DatabaseShardingState::get(_db);
auto dssLock = DatabaseShardingState::DSSLock::lockShared(opCtx, &dss);
dss.checkDbVersion(opCtx, dssLock);
}
ConcealCollectionCatalogChangesBlock::ConcealCollectionCatalogChangesBlock(OperationContext* opCtx)
: _opCtx(opCtx) {
CollectionCatalog::get(_opCtx).onCloseCatalog(_opCtx);
}
ConcealCollectionCatalogChangesBlock::~ConcealCollectionCatalogChangesBlock() {
invariant(_opCtx);
CollectionCatalog::get(_opCtx).onOpenCatalog(_opCtx);
}
ReadSourceScope::ReadSourceScope(OperationContext* opCtx,
RecoveryUnit::ReadSource readSource,
boost::optional<Timestamp> provided)
: _opCtx(opCtx), _originalReadSource(opCtx->recoveryUnit()->getTimestampReadSource()) {
if (_originalReadSource == RecoveryUnit::ReadSource::kProvided) {
_originalReadTimestamp = *_opCtx->recoveryUnit()->getPointInTimeReadTimestamp();
}
_opCtx->recoveryUnit()->abandonSnapshot();
_opCtx->recoveryUnit()->setTimestampReadSource(readSource, provided);
}
ReadSourceScope::~ReadSourceScope() {
_opCtx->recoveryUnit()->abandonSnapshot();
if (_originalReadSource == RecoveryUnit::ReadSource::kProvided) {
_opCtx->recoveryUnit()->setTimestampReadSource(_originalReadSource, _originalReadTimestamp);
} else {
_opCtx->recoveryUnit()->setTimestampReadSource(_originalReadSource);
}
}
} // namespace mongo
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