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rust-rocksdb/file/writable_file_writer.h

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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
// Copyright (c) 2011 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.
#pragma once
#include <atomic>
#include <string>
#include "db/version_edit.h"
#include "env/file_system_tracer.h"
#include "port/port.h"
#include "rocksdb/file_checksum.h"
#include "rocksdb/file_system.h"
#include "rocksdb/io_status.h"
#include "rocksdb/listener.h"
#include "rocksdb/rate_limiter.h"
#include "test_util/sync_point.h"
#include "util/aligned_buffer.h"
namespace ROCKSDB_NAMESPACE {
class Statistics;
class SystemClock;
// WritableFileWriter is a wrapper on top of Env::WritableFile. It provides
// facilities to:
// - Handle Buffered and Direct writes.
// - Rate limit writes.
// - Flush and Sync the data to the underlying filesystem.
// - Notify any interested listeners on the completion of a write.
// - Update IO stats.
class WritableFileWriter {
private:
void NotifyOnFileWriteFinish(
uint64_t offset, size_t length,
const FileOperationInfo::StartTimePoint& start_ts,
const FileOperationInfo::FinishTimePoint& finish_ts,
const IOStatus& io_status) {
FileOperationInfo info(FileOperationType::kWrite, file_name_, start_ts,
finish_ts, io_status, temperature_);
info.offset = offset;
info.length = length;
for (auto& listener : listeners_) {
listener->OnFileWriteFinish(info);
}
info.status.PermitUncheckedError();
}
void NotifyOnFileFlushFinish(
const FileOperationInfo::StartTimePoint& start_ts,
const FileOperationInfo::FinishTimePoint& finish_ts,
const IOStatus& io_status) {
FileOperationInfo info(FileOperationType::kFlush, file_name_, start_ts,
finish_ts, io_status, temperature_);
for (auto& listener : listeners_) {
listener->OnFileFlushFinish(info);
}
info.status.PermitUncheckedError();
}
void NotifyOnFileSyncFinish(
const FileOperationInfo::StartTimePoint& start_ts,
const FileOperationInfo::FinishTimePoint& finish_ts,
const IOStatus& io_status,
FileOperationType type = FileOperationType::kSync) {
FileOperationInfo info(type, file_name_, start_ts, finish_ts, io_status,
temperature_);
for (auto& listener : listeners_) {
listener->OnFileSyncFinish(info);
}
info.status.PermitUncheckedError();
}
void NotifyOnFileRangeSyncFinish(
uint64_t offset, size_t length,
const FileOperationInfo::StartTimePoint& start_ts,
const FileOperationInfo::FinishTimePoint& finish_ts,
const IOStatus& io_status) {
FileOperationInfo info(FileOperationType::kRangeSync, file_name_, start_ts,
finish_ts, io_status, temperature_);
info.offset = offset;
info.length = length;
for (auto& listener : listeners_) {
listener->OnFileRangeSyncFinish(info);
}
info.status.PermitUncheckedError();
}
void NotifyOnFileTruncateFinish(
const FileOperationInfo::StartTimePoint& start_ts,
const FileOperationInfo::FinishTimePoint& finish_ts,
const IOStatus& io_status) {
FileOperationInfo info(FileOperationType::kTruncate, file_name_, start_ts,
finish_ts, io_status, temperature_);
for (auto& listener : listeners_) {
listener->OnFileTruncateFinish(info);
}
info.status.PermitUncheckedError();
}
void NotifyOnFileCloseFinish(
const FileOperationInfo::StartTimePoint& start_ts,
const FileOperationInfo::FinishTimePoint& finish_ts,
const IOStatus& io_status) {
FileOperationInfo info(FileOperationType::kClose, file_name_, start_ts,
finish_ts, io_status, temperature_);
for (auto& listener : listeners_) {
listener->OnFileCloseFinish(info);
}
info.status.PermitUncheckedError();
}
void NotifyOnIOError(const IOStatus& io_status, FileOperationType operation,
const std::string& file_path, size_t length = 0,
uint64_t offset = 0) {
if (listeners_.empty()) {
return;
}
IOErrorInfo io_error_info(io_status, operation, file_path, length, offset);
for (auto& listener : listeners_) {
listener->OnIOError(io_error_info);
}
io_error_info.io_status.PermitUncheckedError();
}
bool ShouldNotifyListeners() const { return !listeners_.empty(); }
void UpdateFileChecksum(const Slice& data);
void Crc32cHandoffChecksumCalculation(const char* data, size_t size,
char* buf);
std::string file_name_;
FSWritableFilePtr writable_file_;
SystemClock* clock_;
AlignedBuffer buf_;
size_t max_buffer_size_;
// Actually written data size can be used for truncate
// not counting padding data
std::atomic<uint64_t> filesize_;
std::atomic<uint64_t> flushed_size_;
// This is necessary when we use unbuffered access
// and writes must happen on aligned offsets
// so we need to go back and write that page again
uint64_t next_write_offset_;
bool pending_sync_;
std::atomic<bool> seen_error_;
#ifndef NDEBUG
// SyncWithoutFlush() is the function that is allowed to be called
// concurrently with other function. One of the concurrent call
// could set seen_error_, and the other one would hit assertion
// in debug mode.
std::atomic<bool> sync_without_flush_called_ = false;
#endif // NDEBUG
uint64_t last_sync_size_;
uint64_t bytes_per_sync_;
RateLimiter* rate_limiter_;
Statistics* stats_;
std::vector<std::shared_ptr<EventListener>> listeners_;
std::unique_ptr<FileChecksumGenerator> checksum_generator_;
bool checksum_finalized_;
bool perform_data_verification_;
uint32_t buffered_data_crc32c_checksum_;
bool buffered_data_with_checksum_;
Temperature temperature_;
public:
WritableFileWriter(
std::unique_ptr<FSWritableFile>&& file, const std::string& _file_name,
const FileOptions& options, SystemClock* clock = nullptr,
const std::shared_ptr<IOTracer>& io_tracer = nullptr,
Statistics* stats = nullptr,
const std::vector<std::shared_ptr<EventListener>>& listeners = {},
FileChecksumGenFactory* file_checksum_gen_factory = nullptr,
bool perform_data_verification = false,
bool buffered_data_with_checksum = false)
: file_name_(_file_name),
writable_file_(std::move(file), io_tracer, _file_name),
clock_(clock),
buf_(),
max_buffer_size_(options.writable_file_max_buffer_size),
filesize_(0),
flushed_size_(0),
next_write_offset_(0),
pending_sync_(false),
seen_error_(false),
last_sync_size_(0),
bytes_per_sync_(options.bytes_per_sync),
rate_limiter_(options.rate_limiter),
stats_(stats),
listeners_(),
checksum_generator_(nullptr),
checksum_finalized_(false),
perform_data_verification_(perform_data_verification),
buffered_data_crc32c_checksum_(0),
buffered_data_with_checksum_(buffered_data_with_checksum) {
temperature_ = options.temperature;
assert(!use_direct_io() || max_buffer_size_ > 0);
TEST_SYNC_POINT_CALLBACK("WritableFileWriter::WritableFileWriter:0",
reinterpret_cast<void*>(max_buffer_size_));
buf_.Alignment(writable_file_->GetRequiredBufferAlignment());
buf_.AllocateNewBuffer(std::min((size_t)65536, max_buffer_size_));
std::for_each(listeners.begin(), listeners.end(),
[this](const std::shared_ptr<EventListener>& e) {
if (e->ShouldBeNotifiedOnFileIO()) {
listeners_.emplace_back(e);
}
});
if (file_checksum_gen_factory != nullptr) {
FileChecksumGenContext checksum_gen_context;
checksum_gen_context.file_name = _file_name;
checksum_generator_ =
file_checksum_gen_factory->CreateFileChecksumGenerator(
checksum_gen_context);
}
}
static IOStatus Create(const std::shared_ptr<FileSystem>& fs,
const std::string& fname, const FileOptions& file_opts,
std::unique_ptr<WritableFileWriter>* writer,
IODebugContext* dbg);
WritableFileWriter(const WritableFileWriter&) = delete;
WritableFileWriter& operator=(const WritableFileWriter&) = delete;
~WritableFileWriter() {
auto s = Close();
s.PermitUncheckedError();
}
std::string file_name() const { return file_name_; }
// When this Append API is called, if the crc32c_checksum is not provided, we
// will calculate the checksum internally.
IOStatus Append(const Slice& data, uint32_t crc32c_checksum = 0,
Env::IOPriority op_rate_limiter_priority = Env::IO_TOTAL);
IOStatus Pad(const size_t pad_bytes,
Env::IOPriority op_rate_limiter_priority = Env::IO_TOTAL);
IOStatus Flush(Env::IOPriority op_rate_limiter_priority = Env::IO_TOTAL);
IOStatus Close();
IOStatus Sync(bool use_fsync);
// Sync only the data that was already Flush()ed. Safe to call concurrently
// with Append() and Flush(). If !writable_file_->IsSyncThreadSafe(),
// returns NotSupported status.
IOStatus SyncWithoutFlush(bool use_fsync);
uint64_t GetFileSize() const {
return filesize_.load(std::memory_order_acquire);
}
// Returns the size of data flushed to the underlying `FSWritableFile`.
// Expected to match `writable_file()->GetFileSize()`.
// The return value can serve as a lower-bound for the amount of data synced
// by a future call to `SyncWithoutFlush()`.
uint64_t GetFlushedSize() const {
return flushed_size_.load(std::memory_order_acquire);
}
IOStatus InvalidateCache(size_t offset, size_t length) {
return writable_file_->InvalidateCache(offset, length);
}
FSWritableFile* writable_file() const { return writable_file_.get(); }
bool use_direct_io() { return writable_file_->use_direct_io(); }
bool BufferIsEmpty() { return buf_.CurrentSize() == 0; }
void TEST_SetFileChecksumGenerator(
FileChecksumGenerator* checksum_generator) {
checksum_generator_.reset(checksum_generator);
}
std::string GetFileChecksum();
const char* GetFileChecksumFuncName() const;
bool seen_error() const {
return seen_error_.load(std::memory_order_relaxed);
}
// For options of relaxed consistency, users might hope to continue
// operating on the file after an error happens.
void reset_seen_error() {
seen_error_.store(false, std::memory_order_relaxed);
}
void set_seen_error() { seen_error_.store(true, std::memory_order_relaxed); }
IOStatus AssertFalseAndGetStatusForPrevError() {
// This should only happen if SyncWithoutFlush() was called.
assert(sync_without_flush_called_);
return IOStatus::IOError("Writer has previous error.");
}
private:
// Decide the Rate Limiter priority.
static Env::IOPriority DecideRateLimiterPriority(
Env::IOPriority writable_file_io_priority,
Env::IOPriority op_rate_limiter_priority);
// Used when os buffering is OFF and we are writing
// DMA such as in Direct I/O mode
IOStatus WriteDirect(Env::IOPriority op_rate_limiter_priority);
IOStatus WriteDirectWithChecksum(Env::IOPriority op_rate_limiter_priority);
// Normal write.
IOStatus WriteBuffered(const char* data, size_t size,
Env::IOPriority op_rate_limiter_priority);
IOStatus WriteBufferedWithChecksum(const char* data, size_t size,
Env::IOPriority op_rate_limiter_priority);
IOStatus RangeSync(uint64_t offset, uint64_t nbytes);
IOStatus SyncInternal(bool use_fsync);
};
} // namespace ROCKSDB_NAMESPACE