作者: 韩晨旭 10225101440 李畅 10225102463
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// Copyright 2014 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
// This test uses a custom Env to keep track of the state of a filesystem as of
// the last "sync". It then checks for data loss errors by purposely dropping
// file data (or entire files) not protected by a "sync".
#include <map>
#include <set>
#include "gtest/gtest.h"
#include "db/db_impl.h"
#include "db/filename.h"
#include "db/log_format.h"
#include "db/version_set.h"
#include "leveldb/cache.h"
#include "leveldb/db.h"
#include "leveldb/env.h"
#include "leveldb/table.h"
#include "leveldb/write_batch.h"
#include "port/port.h"
#include "port/thread_annotations.h"
#include "util/logging.h"
#include "util/mutexlock.h"
#include "util/testutil.h"
namespace leveldb {
static const int kValueSize = 1000;
static const int kMaxNumValues = 2000;
static const size_t kNumIterations = 3;
class FaultInjectionTestEnv;
namespace {
// Assume a filename, and not a directory name like "/foo/bar/"
static std::string GetDirName(const std::string& filename) {
size_t found = filename.find_last_of("/\\");
if (found == std::string::npos) {
return "";
} else {
return filename.substr(0, found);
}
}
Status SyncDir(const std::string& dir) {
// As this is a test it isn't required to *actually* sync this directory.
return Status::OK();
}
// A basic file truncation function suitable for this test.
Status Truncate(const std::string& filename, uint64_t length) {
leveldb::Env* env = leveldb::Env::Default();
SequentialFile* orig_file;
Status s = env->NewSequentialFile(filename, &orig_file);
if (!s.ok()) return s;
char* scratch = new char[length];
leveldb::Slice result;
s = orig_file->Read(length, &result, scratch);
delete orig_file;
if (s.ok()) {
std::string tmp_name = GetDirName(filename) + "/truncate.tmp";
WritableFile* tmp_file;
s = env->NewWritableFile(tmp_name, &tmp_file);
if (s.ok()) {
s = tmp_file->Append(result);
delete tmp_file;
if (s.ok()) {
s = env->RenameFile(tmp_name, filename);
} else {
env->RemoveFile(tmp_name);
}
}
}
delete[] scratch;
return s;
}
struct FileState {
std::string filename_;
int64_t pos_;
int64_t pos_at_last_sync_;
int64_t pos_at_last_flush_;
FileState(const std::string& filename)
: filename_(filename),
pos_(-1),
pos_at_last_sync_(-1),
pos_at_last_flush_(-1) {}
FileState() : pos_(-1), pos_at_last_sync_(-1), pos_at_last_flush_(-1) {}
bool IsFullySynced() const { return pos_ <= 0 || pos_ == pos_at_last_sync_; }
Status DropUnsyncedData() const;
};
} // anonymous namespace
// A wrapper around WritableFile which informs another Env whenever this file
// is written to or sync'ed.
class TestWritableFile : public WritableFile {
public:
TestWritableFile(const FileState& state, WritableFile* f,
FaultInjectionTestEnv* env);
~TestWritableFile() override;
Status Append(const Slice& data) override;
Status Close() override;
Status Flush() override;
Status Sync() override;
private:
FileState state_;
WritableFile* target_;
bool writable_file_opened_;
FaultInjectionTestEnv* env_;
Status SyncParent();
};
class FaultInjectionTestEnv : public EnvWrapper {
public:
FaultInjectionTestEnv()
: EnvWrapper(Env::Default()), filesystem_active_(true) {}
~FaultInjectionTestEnv() override = default;
Status NewWritableFile(const std::string& fname,
WritableFile** result) override;
Status NewAppendableFile(const std::string& fname,
WritableFile** result) override;
Status RemoveFile(const std::string& f) override;
Status RenameFile(const std::string& s, const std::string& t) override;
void WritableFileClosed(const FileState& state);
Status DropUnsyncedFileData();
Status RemoveFilesCreatedAfterLastDirSync();
void DirWasSynced();
bool IsFileCreatedSinceLastDirSync(const std::string& filename);
void ResetState();
void UntrackFile(const std::string& f);
// Setting the filesystem to inactive is the test equivalent to simulating a
// system reset. Setting to inactive will freeze our saved filesystem state so
// that it will stop being recorded. It can then be reset back to the state at
// the time of the reset.
bool IsFilesystemActive() LOCKS_EXCLUDED(mutex_) {
MutexLock l(&mutex_);
return filesystem_active_;
}
void SetFilesystemActive(bool active) LOCKS_EXCLUDED(mutex_) {
MutexLock l(&mutex_);
filesystem_active_ = active;
}
private:
port::Mutex mutex_;
std::map<std::string, FileState> db_file_state_ GUARDED_BY(mutex_);
std::set<std::string> new_files_since_last_dir_sync_ GUARDED_BY(mutex_);
bool filesystem_active_ GUARDED_BY(mutex_); // Record flushes, syncs, writes
};
TestWritableFile::TestWritableFile(const FileState& state, WritableFile* f,
FaultInjectionTestEnv* env)
: state_(state), target_(f), writable_file_opened_(true), env_(env) {
assert(f != nullptr);
}
TestWritableFile::~TestWritableFile() {
if (writable_file_opened_) {
Close();
}
delete target_;
}
Status TestWritableFile::Append(const Slice& data) {
Status s = target_->Append(data);
if (s.ok() && env_->IsFilesystemActive()) {
state_.pos_ += data.size();
}
return s;
}
Status TestWritableFile::Close() {
writable_file_opened_ = false;
Status s = target_->Close();
if (s.ok()) {
env_->WritableFileClosed(state_);
}
return s;
}
Status TestWritableFile::Flush() {
Status s = target_->Flush();
if (s.ok() && env_->IsFilesystemActive()) {
state_.pos_at_last_flush_ = state_.pos_;
}
return s;
}
Status TestWritableFile::SyncParent() {
Status s = SyncDir(GetDirName(state_.filename_));
if (s.ok()) {
env_->DirWasSynced();
}
return s;
}
Status TestWritableFile::Sync() {
if (!env_->IsFilesystemActive()) {
return Status::OK();
}
// Ensure new files referred to by the manifest are in the filesystem.
Status s = target_->Sync();
if (s.ok()) {
state_.pos_at_last_sync_ = state_.pos_;
}
if (env_->IsFileCreatedSinceLastDirSync(state_.filename_)) {
Status ps = SyncParent();
if (s.ok() && !ps.ok()) {
s = ps;
}
}
return s;
}
Status FaultInjectionTestEnv::NewWritableFile(const std::string& fname,
WritableFile** result) {
WritableFile* actual_writable_file;
Status s = target()->NewWritableFile(fname, &actual_writable_file);
if (s.ok()) {
FileState state(fname);
state.pos_ = 0;
*result = new TestWritableFile(state, actual_writable_file, this);
// NewWritableFile doesn't append to files, so if the same file is
// opened again then it will be truncated - so forget our saved
// state.
UntrackFile(fname);
MutexLock l(&mutex_);
new_files_since_last_dir_sync_.insert(fname);
}
return s;
}
Status FaultInjectionTestEnv::NewAppendableFile(const std::string& fname,
WritableFile** result) {
WritableFile* actual_writable_file;
Status s = target()->NewAppendableFile(fname, &actual_writable_file);
if (s.ok()) {
FileState state(fname);
state.pos_ = 0;
{
MutexLock l(&mutex_);
if (db_file_state_.count(fname) == 0) {
new_files_since_last_dir_sync_.insert(fname);
} else {
state = db_file_state_[fname];
}
}
*result = new TestWritableFile(state, actual_writable_file, this);
}
return s;
}
Status FaultInjectionTestEnv::DropUnsyncedFileData() {
Status s;
MutexLock l(&mutex_);
for (const auto& kvp : db_file_state_) {
if (!s.ok()) {
break;
}
const FileState& state = kvp.second;
if (!state.IsFullySynced()) {
s = state.DropUnsyncedData();
}
}
return s;
}
void FaultInjectionTestEnv::DirWasSynced() {
MutexLock l(&mutex_);
new_files_since_last_dir_sync_.clear();
}
bool FaultInjectionTestEnv::IsFileCreatedSinceLastDirSync(
const std::string& filename) {
MutexLock l(&mutex_);
return new_files_since_last_dir_sync_.find(filename) !=
new_files_since_last_dir_sync_.end();
}
void FaultInjectionTestEnv::UntrackFile(const std::string& f) {
MutexLock l(&mutex_);
db_file_state_.erase(f);
new_files_since_last_dir_sync_.erase(f);
}
Status FaultInjectionTestEnv::RemoveFile(const std::string& f) {
Status s = EnvWrapper::RemoveFile(f);
EXPECT_LEVELDB_OK(s);
if (s.ok()) {
UntrackFile(f);
}
return s;
}
Status FaultInjectionTestEnv::RenameFile(const std::string& s,
const std::string& t) {
Status ret = EnvWrapper::RenameFile(s, t);
if (ret.ok()) {
MutexLock l(&mutex_);
if (db_file_state_.find(s) != db_file_state_.end()) {
db_file_state_[t] = db_file_state_[s];
db_file_state_.erase(s);
}
if (new_files_since_last_dir_sync_.erase(s) != 0) {
assert(new_files_since_last_dir_sync_.find(t) ==
new_files_since_last_dir_sync_.end());
new_files_since_last_dir_sync_.insert(t);
}
}
return ret;
}
void FaultInjectionTestEnv::ResetState() {
// Since we are not destroying the database, the existing files
// should keep their recorded synced/flushed state. Therefore
// we do not reset db_file_state_ and new_files_since_last_dir_sync_.
SetFilesystemActive(true);
}
Status FaultInjectionTestEnv::RemoveFilesCreatedAfterLastDirSync() {
// Because RemoveFile access this container make a copy to avoid deadlock
mutex_.Lock();
std::set<std::string> new_files(new_files_since_last_dir_sync_.begin(),
new_files_since_last_dir_sync_.end());
mutex_.Unlock();
Status status;
for (const auto& new_file : new_files) {
Status remove_status = RemoveFile(new_file);
if (!remove_status.ok() && status.ok()) {
status = std::move(remove_status);
}
}
return status;
}
void FaultInjectionTestEnv::WritableFileClosed(const FileState& state) {
MutexLock l(&mutex_);
db_file_state_[state.filename_] = state;
}
Status FileState::DropUnsyncedData() const {
int64_t sync_pos = pos_at_last_sync_ == -1 ? 0 : pos_at_last_sync_;
return Truncate(filename_, sync_pos);
}
class FaultInjectionTest : public testing::Test {
public:
enum ExpectedVerifResult { VAL_EXPECT_NO_ERROR, VAL_EXPECT_ERROR };
enum ResetMethod { RESET_DROP_UNSYNCED_DATA, RESET_DELETE_UNSYNCED_FILES };
FaultInjectionTestEnv* env_;
std::string dbname_;
Cache* tiny_cache_;
Options options_;
DB* db_;
FaultInjectionTest()
: env_(new FaultInjectionTestEnv),
tiny_cache_(NewLRUCache(100)),
db_(nullptr) {
dbname_ = testing::TempDir() + "fault_test";
DestroyDB(dbname_, Options()); // Destroy any db from earlier run
options_.reuse_logs = true;
options_.env = env_;
options_.paranoid_checks = true;
options_.block_cache = tiny_cache_;
options_.create_if_missing = true;
}
~FaultInjectionTest() {
CloseDB();
DestroyDB(dbname_, Options());
delete tiny_cache_;
delete env_;
}
void ReuseLogs(bool reuse) { options_.reuse_logs = reuse; }
void Build(int start_idx, int num_vals) {
std::string key_space, value_space;
WriteBatch batch;
for (int i = start_idx; i < start_idx + num_vals; i++) {
Slice key = Key(i, &key_space);
batch.Clear();
batch.Put(key, Value(i, &value_space));
WriteOptions options;
ASSERT_LEVELDB_OK(db_->Write(options, &batch));
}
}
Status ReadValue(int i, std::string* val) const {
std::string key_space, value_space;
Slice key = Key(i, &key_space);
Value(i, &value_space);
ReadOptions options;
return db_->Get(options, key, val);
}
Status Verify(int start_idx, int num_vals,
ExpectedVerifResult expected) const {
std::string val;
std::string value_space;
Status s;
for (int i = start_idx; i < start_idx + num_vals && s.ok(); i++) {
Value(i, &value_space);
s = ReadValue(i, &val);
if (expected == VAL_EXPECT_NO_ERROR) {
if (s.ok()) {
EXPECT_EQ(value_space, val);
}
} else if (s.ok()) {
std::fprintf(stderr, "Expected an error at %d, but was OK\n", i);
s = Status::IOError(dbname_, "Expected value error:");
} else {
s = Status::OK(); // An expected error
}
}
return s;
}
// Return the ith key
Slice Key(int i, std::string* storage) const {
char buf[100];
std::snprintf(buf, sizeof(buf), "%016d", i);
storage->assign(buf, strlen(buf));
return Slice(*storage);
}
// Return the value to associate with the specified key
Slice Value(int k, std::string* storage) const {
Random r(k);
return test::RandomString(&r, kValueSize, storage);
}
Status OpenDB() {
delete db_;
db_ = nullptr;
env_->ResetState();
return DB::Open(options_, dbname_, &db_);
}
void CloseDB() {
delete db_;
db_ = nullptr;
}
void DeleteAllData() {
Iterator* iter = db_->NewIterator(ReadOptions());
for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
ASSERT_LEVELDB_OK(db_->Delete(WriteOptions(), iter->key()));
}
delete iter;
}
void ResetDBState(ResetMethod reset_method) {
switch (reset_method) {
case RESET_DROP_UNSYNCED_DATA:
ASSERT_LEVELDB_OK(env_->DropUnsyncedFileData());
break;
case RESET_DELETE_UNSYNCED_FILES:
ASSERT_LEVELDB_OK(env_->RemoveFilesCreatedAfterLastDirSync());
break;
default:
assert(false);
}
}
void PartialCompactTestPreFault(int num_pre_sync, int num_post_sync) {
DeleteAllData();
Build(0, num_pre_sync);
db_->CompactRange(nullptr, nullptr);
Build(num_pre_sync, num_post_sync);
}
void PartialCompactTestReopenWithFault(ResetMethod reset_method,
int num_pre_sync, int num_post_sync) {
env_->SetFilesystemActive(false);
CloseDB();
ResetDBState(reset_method);
ASSERT_LEVELDB_OK(OpenDB());
ASSERT_LEVELDB_OK(
Verify(0, num_pre_sync, FaultInjectionTest::VAL_EXPECT_NO_ERROR));
ASSERT_LEVELDB_OK(Verify(num_pre_sync, num_post_sync,
FaultInjectionTest::VAL_EXPECT_ERROR));
}
void NoWriteTestPreFault() {}
void NoWriteTestReopenWithFault(ResetMethod reset_method) {
CloseDB();
ResetDBState(reset_method);
ASSERT_LEVELDB_OK(OpenDB());
}
void DoTest() {
Random rnd(0);
ASSERT_LEVELDB_OK(OpenDB());
for (size_t idx = 0; idx < kNumIterations; idx++) {
int num_pre_sync = rnd.Uniform(kMaxNumValues);
int num_post_sync = rnd.Uniform(kMaxNumValues);
PartialCompactTestPreFault(num_pre_sync, num_post_sync);
PartialCompactTestReopenWithFault(RESET_DROP_UNSYNCED_DATA, num_pre_sync,
num_post_sync);
NoWriteTestPreFault();
NoWriteTestReopenWithFault(RESET_DROP_UNSYNCED_DATA);
PartialCompactTestPreFault(num_pre_sync, num_post_sync);
// No new files created so we expect all values since no files will be
// dropped.
PartialCompactTestReopenWithFault(RESET_DELETE_UNSYNCED_FILES,
num_pre_sync + num_post_sync, 0);
NoWriteTestPreFault();
NoWriteTestReopenWithFault(RESET_DELETE_UNSYNCED_FILES);
}
}
};
TEST_F(FaultInjectionTest, FaultTestNoLogReuse) {
ReuseLogs(false);
DoTest();
}
TEST_F(FaultInjectionTest, FaultTestWithLogReuse) {
ReuseLogs(true);
DoTest();
}
} // namespace leveldb