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/**
* Copyright (C) 2014 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/db/concurrency/lock_manager_test_help.h"
#include "mongo/unittest/unittest.h"
namespace mongo {
TEST(Deadlock, NoDeadlock) {
const ResourceId resId(RESOURCE_DATABASE, std::string("A"));
LockerForTests locker1(MODE_IS);
LockerForTests locker2(MODE_IS);
ASSERT_EQUALS(LOCK_OK, locker1.lockBegin(resId, MODE_S));
ASSERT_EQUALS(LOCK_OK, locker2.lockBegin(resId, MODE_S));
DeadlockDetector wfg1(*getGlobalLockManager(), &locker1);
ASSERT(!wfg1.check().hasCycle());
DeadlockDetector wfg2(*getGlobalLockManager(), &locker2);
ASSERT(!wfg2.check().hasCycle());
}
TEST(Deadlock, Simple) {
const ResourceId resIdA(RESOURCE_DATABASE, std::string("A"));
const ResourceId resIdB(RESOURCE_DATABASE, std::string("B"));
LockerForTests locker1(MODE_IX);
LockerForTests locker2(MODE_IX);
ASSERT_EQUALS(LOCK_OK, locker1.lockBegin(resIdA, MODE_X));
ASSERT_EQUALS(LOCK_OK, locker2.lockBegin(resIdB, MODE_X));
// 1 -> 2
ASSERT_EQUALS(LOCK_WAITING, locker1.lockBegin(resIdB, MODE_X));
// 2 -> 1
ASSERT_EQUALS(LOCK_WAITING, locker2.lockBegin(resIdA, MODE_X));
DeadlockDetector wfg1(*getGlobalLockManager(), &locker1);
ASSERT(wfg1.check().hasCycle());
DeadlockDetector wfg2(*getGlobalLockManager(), &locker2);
ASSERT(wfg2.check().hasCycle());
// Cleanup, so that LockerImpl doesn't complain about leaked locks
locker1.unlock(resIdB);
locker2.unlock(resIdA);
}
TEST(Deadlock, SimpleUpgrade) {
const ResourceId resId(RESOURCE_DATABASE, std::string("A"));
LockerForTests locker1(MODE_IX);
LockerForTests locker2(MODE_IX);
// Both acquire lock in intent mode
ASSERT_EQUALS(LOCK_OK, locker1.lockBegin(resId, MODE_IX));
ASSERT_EQUALS(LOCK_OK, locker2.lockBegin(resId, MODE_IX));
// Both try to upgrade
ASSERT_EQUALS(LOCK_WAITING, locker1.lockBegin(resId, MODE_X));
ASSERT_EQUALS(LOCK_WAITING, locker2.lockBegin(resId, MODE_X));
DeadlockDetector wfg1(*getGlobalLockManager(), &locker1);
ASSERT(wfg1.check().hasCycle());
DeadlockDetector wfg2(*getGlobalLockManager(), &locker2);
ASSERT(wfg2.check().hasCycle());
// Cleanup, so that LockerImpl doesn't complain about leaked locks
locker1.unlock(resId);
locker2.unlock(resId);
}
TEST(Deadlock, Indirect) {
const ResourceId resIdA(RESOURCE_DATABASE, std::string("A"));
const ResourceId resIdB(RESOURCE_DATABASE, std::string("B"));
LockerForTests locker1(MODE_IX);
LockerForTests locker2(MODE_IX);
LockerForTests lockerIndirect(MODE_IX);
ASSERT_EQUALS(LOCK_OK, locker1.lockBegin(resIdA, MODE_X));
ASSERT_EQUALS(LOCK_OK, locker2.lockBegin(resIdB, MODE_X));
// 1 -> 2
ASSERT_EQUALS(LOCK_WAITING, locker1.lockBegin(resIdB, MODE_X));
// 2 -> 1
ASSERT_EQUALS(LOCK_WAITING, locker2.lockBegin(resIdA, MODE_X));
// 3 -> 2
ASSERT_EQUALS(LOCK_WAITING, lockerIndirect.lockBegin(resIdA, MODE_X));
DeadlockDetector wfg1(*getGlobalLockManager(), &locker1);
ASSERT(wfg1.check().hasCycle());
DeadlockDetector wfg2(*getGlobalLockManager(), &locker2);
ASSERT(wfg2.check().hasCycle());
// Indirect locker should not report the cycle since it does not participate in it
DeadlockDetector wfgIndirect(*getGlobalLockManager(), &lockerIndirect);
ASSERT(!wfgIndirect.check().hasCycle());
// Cleanup, so that LockerImpl doesn't complain about leaked locks
locker1.unlock(resIdB);
locker2.unlock(resIdA);
}
TEST(Deadlock, IndirectWithUpgrade) {
const ResourceId resIdFlush(RESOURCE_MMAPV1_FLUSH, 1);
const ResourceId resIdDb(RESOURCE_DATABASE, 2);
LockerForTests flush(MODE_IX);
LockerForTests reader(MODE_IS);
LockerForTests writer(MODE_IX);
// This sequence simulates the deadlock which occurs during flush
ASSERT_EQUALS(LOCK_OK, writer.lockBegin(resIdFlush, MODE_IX));
ASSERT_EQUALS(LOCK_OK, writer.lockBegin(resIdDb, MODE_X));
ASSERT_EQUALS(LOCK_OK, reader.lockBegin(resIdFlush, MODE_IS));
// R -> W
ASSERT_EQUALS(LOCK_WAITING, reader.lockBegin(resIdDb, MODE_S));
// R -> W
// F -> W
ASSERT_EQUALS(LOCK_WAITING, flush.lockBegin(resIdFlush, MODE_S));
// W yields its flush lock, so now f is granted in mode S
//
// R -> W
writer.unlock(resIdFlush);
// Flush thread upgrades S -> X in order to do the remap
//
// R -> W
// F -> R
ASSERT_EQUALS(LOCK_WAITING, flush.lockBegin(resIdFlush, MODE_X));
// W comes back from the commit and tries to re-acquire the flush lock
//
// R -> W
// F -> R
// W -> F
ASSERT_EQUALS(LOCK_WAITING, writer.lockBegin(resIdFlush, MODE_IX));
// Run deadlock detection from the point of view of each of the involved lockers
DeadlockDetector wfgF(*getGlobalLockManager(), &flush);
ASSERT(wfgF.check().hasCycle());
DeadlockDetector wfgR(*getGlobalLockManager(), &reader);
ASSERT(wfgR.check().hasCycle());
DeadlockDetector wfgW(*getGlobalLockManager(), &writer);
ASSERT(wfgW.check().hasCycle());
// Cleanup, so that LockerImpl doesn't complain about leaked locks
flush.unlock(resIdFlush);
writer.unlock(resIdFlush);
}
} // namespace mongo
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