rocksdb/env/io_posix.h
Jay Zhuang 29102641dd Skip directory fsync for filesystem btrfs (#8903)
Summary:
Directory fsync might be expensive on btrfs and it may not be needed.
Here are 4 directory fsync cases:
1. creating a new file: dir-fsync is not needed on btrfs, as long as the
   new file itself is synced.
2. renaming a file: dir-fsync is not needed if the renamed file is
   synced. So an API `FsyncAfterFileRename(filename, ...)` is provided
   to sync the file on btrfs. By default, it just calls dir-fsync.
3. deleting files: dir-fsync is forced by set
   `IOOptions.force_dir_fsync = true`
4. renaming multiple files (like backup and checkpoint): dir-fsync is
   forced, the same as above.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8903

Test Plan: run tests on btrfs and non btrfs

Reviewed By: ajkr

Differential Revision: D30885059

Pulled By: jay-zhuang

fbshipit-source-id: dd2730b31580b0bcaedffc318a762d7dbf25de4a
2021-11-03 12:21:27 -07:00

408 lines
15 KiB
C++

// 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 <errno.h>
#if defined(ROCKSDB_IOURING_PRESENT)
#include <liburing.h>
#include <sys/uio.h>
#endif
#include <unistd.h>
#include <atomic>
#include <functional>
#include <map>
#include <string>
#include "port/port.h"
#include "rocksdb/env.h"
#include "rocksdb/file_system.h"
#include "rocksdb/io_status.h"
#include "util/mutexlock.h"
#include "util/thread_local.h"
// For non linux platform, the following macros are used only as place
// holder.
#if !(defined OS_LINUX) && !(defined CYGWIN) && !(defined OS_AIX)
#define POSIX_FADV_NORMAL 0 /* [MC1] no further special treatment */
#define POSIX_FADV_RANDOM 1 /* [MC1] expect random page refs */
#define POSIX_FADV_SEQUENTIAL 2 /* [MC1] expect sequential page refs */
#define POSIX_FADV_WILLNEED 3 /* [MC1] will need these pages */
#define POSIX_FADV_DONTNEED 4 /* [MC1] don't need these pages */
#endif
namespace ROCKSDB_NAMESPACE {
std::string IOErrorMsg(const std::string& context,
const std::string& file_name);
// file_name can be left empty if it is not unkown.
IOStatus IOError(const std::string& context, const std::string& file_name,
int err_number);
class PosixHelper {
public:
static size_t GetUniqueIdFromFile(int fd, char* id, size_t max_size);
static size_t GetLogicalBlockSizeOfFd(int fd);
static Status GetLogicalBlockSizeOfDirectory(const std::string& directory,
size_t* size);
};
#ifdef OS_LINUX
// Files under a specific directory have the same logical block size.
// This class caches the logical block size for the specified directories to
// save the CPU cost of computing the size.
// Safe for concurrent access from multiple threads without any external
// synchronization.
class LogicalBlockSizeCache {
public:
LogicalBlockSizeCache(
std::function<size_t(int)> get_logical_block_size_of_fd =
PosixHelper::GetLogicalBlockSizeOfFd,
std::function<Status(const std::string&, size_t*)>
get_logical_block_size_of_directory =
PosixHelper::GetLogicalBlockSizeOfDirectory)
: get_logical_block_size_of_fd_(get_logical_block_size_of_fd),
get_logical_block_size_of_directory_(
get_logical_block_size_of_directory) {}
// Takes the following actions:
// 1. Increases reference count of the directories;
// 2. If the directory's logical block size is not cached,
// compute the buffer size and cache the result.
Status RefAndCacheLogicalBlockSize(
const std::vector<std::string>& directories);
// Takes the following actions:
// 1. Decreases reference count of the directories;
// 2. If the reference count of a directory reaches 0, remove the directory
// from the cache.
void UnrefAndTryRemoveCachedLogicalBlockSize(
const std::vector<std::string>& directories);
// Returns the logical block size for the file.
//
// If the file is under a cached directory, return the cached size.
// Otherwise, the size is computed.
size_t GetLogicalBlockSize(const std::string& fname, int fd);
int GetRefCount(const std::string& dir) {
ReadLock lock(&cache_mutex_);
auto it = cache_.find(dir);
if (it == cache_.end()) {
return 0;
}
return it->second.ref;
}
size_t Size() const { return cache_.size(); }
bool Contains(const std::string& dir) {
ReadLock lock(&cache_mutex_);
return cache_.find(dir) != cache_.end();
}
private:
struct CacheValue {
CacheValue() : size(0), ref(0) {}
// Logical block size of the directory.
size_t size;
// Reference count of the directory.
int ref;
};
std::function<size_t(int)> get_logical_block_size_of_fd_;
std::function<Status(const std::string&, size_t*)>
get_logical_block_size_of_directory_;
std::map<std::string, CacheValue> cache_;
port::RWMutex cache_mutex_;
};
#endif
class PosixSequentialFile : public FSSequentialFile {
private:
std::string filename_;
FILE* file_;
int fd_;
bool use_direct_io_;
size_t logical_sector_size_;
public:
PosixSequentialFile(const std::string& fname, FILE* file, int fd,
size_t logical_block_size,
const EnvOptions& options);
virtual ~PosixSequentialFile();
virtual IOStatus Read(size_t n, const IOOptions& opts, Slice* result,
char* scratch, IODebugContext* dbg) override;
virtual IOStatus PositionedRead(uint64_t offset, size_t n,
const IOOptions& opts, Slice* result,
char* scratch, IODebugContext* dbg) override;
virtual IOStatus Skip(uint64_t n) override;
virtual IOStatus InvalidateCache(size_t offset, size_t length) override;
virtual bool use_direct_io() const override { return use_direct_io_; }
virtual size_t GetRequiredBufferAlignment() const override {
return logical_sector_size_;
}
};
#if defined(ROCKSDB_IOURING_PRESENT)
// io_uring instance queue depth
const unsigned int kIoUringDepth = 256;
inline void DeleteIOUring(void* p) {
struct io_uring* iu = static_cast<struct io_uring*>(p);
delete iu;
}
inline struct io_uring* CreateIOUring() {
struct io_uring* new_io_uring = new struct io_uring;
int ret = io_uring_queue_init(kIoUringDepth, new_io_uring, 0);
if (ret) {
delete new_io_uring;
new_io_uring = nullptr;
}
return new_io_uring;
}
#endif // defined(ROCKSDB_IOURING_PRESENT)
class PosixRandomAccessFile : public FSRandomAccessFile {
protected:
std::string filename_;
int fd_;
bool use_direct_io_;
size_t logical_sector_size_;
#if defined(ROCKSDB_IOURING_PRESENT)
ThreadLocalPtr* thread_local_io_urings_;
#endif
public:
PosixRandomAccessFile(const std::string& fname, int fd,
size_t logical_block_size,
const EnvOptions& options
#if defined(ROCKSDB_IOURING_PRESENT)
,
ThreadLocalPtr* thread_local_io_urings
#endif
);
virtual ~PosixRandomAccessFile();
virtual IOStatus Read(uint64_t offset, size_t n, const IOOptions& opts,
Slice* result, char* scratch,
IODebugContext* dbg) const override;
virtual IOStatus MultiRead(FSReadRequest* reqs, size_t num_reqs,
const IOOptions& options,
IODebugContext* dbg) override;
virtual IOStatus Prefetch(uint64_t offset, size_t n, const IOOptions& opts,
IODebugContext* dbg) override;
#if defined(OS_LINUX) || defined(OS_MACOSX) || defined(OS_AIX)
virtual size_t GetUniqueId(char* id, size_t max_size) const override;
#endif
virtual void Hint(AccessPattern pattern) override;
virtual IOStatus InvalidateCache(size_t offset, size_t length) override;
virtual bool use_direct_io() const override { return use_direct_io_; }
virtual size_t GetRequiredBufferAlignment() const override {
return logical_sector_size_;
}
};
class PosixWritableFile : public FSWritableFile {
protected:
const std::string filename_;
const bool use_direct_io_;
int fd_;
uint64_t filesize_;
size_t logical_sector_size_;
#ifdef ROCKSDB_FALLOCATE_PRESENT
bool allow_fallocate_;
bool fallocate_with_keep_size_;
#endif
#ifdef ROCKSDB_RANGESYNC_PRESENT
// Even if the syscall is present, the filesystem may still not properly
// support it, so we need to do a dynamic check too.
bool sync_file_range_supported_;
#endif // ROCKSDB_RANGESYNC_PRESENT
public:
explicit PosixWritableFile(const std::string& fname, int fd,
size_t logical_block_size,
const EnvOptions& options);
virtual ~PosixWritableFile();
// Need to implement this so the file is truncated correctly
// with direct I/O
virtual IOStatus Truncate(uint64_t size, const IOOptions& opts,
IODebugContext* dbg) override;
virtual IOStatus Close(const IOOptions& opts, IODebugContext* dbg) override;
virtual IOStatus Append(const Slice& data, const IOOptions& opts,
IODebugContext* dbg) override;
virtual IOStatus Append(const Slice& data, const IOOptions& opts,
const DataVerificationInfo& /* verification_info */,
IODebugContext* dbg) override {
return Append(data, opts, dbg);
}
virtual IOStatus PositionedAppend(const Slice& data, uint64_t offset,
const IOOptions& opts,
IODebugContext* dbg) override;
virtual IOStatus PositionedAppend(
const Slice& data, uint64_t offset, const IOOptions& opts,
const DataVerificationInfo& /* verification_info */,
IODebugContext* dbg) override {
return PositionedAppend(data, offset, opts, dbg);
}
virtual IOStatus Flush(const IOOptions& opts, IODebugContext* dbg) override;
virtual IOStatus Sync(const IOOptions& opts, IODebugContext* dbg) override;
virtual IOStatus Fsync(const IOOptions& opts, IODebugContext* dbg) override;
virtual bool IsSyncThreadSafe() const override;
virtual bool use_direct_io() const override { return use_direct_io_; }
virtual void SetWriteLifeTimeHint(Env::WriteLifeTimeHint hint) override;
virtual uint64_t GetFileSize(const IOOptions& opts,
IODebugContext* dbg) override;
virtual IOStatus InvalidateCache(size_t offset, size_t length) override;
virtual size_t GetRequiredBufferAlignment() const override {
return logical_sector_size_;
}
#ifdef ROCKSDB_FALLOCATE_PRESENT
virtual IOStatus Allocate(uint64_t offset, uint64_t len,
const IOOptions& opts,
IODebugContext* dbg) override;
#endif
virtual IOStatus RangeSync(uint64_t offset, uint64_t nbytes,
const IOOptions& opts,
IODebugContext* dbg) override;
#ifdef OS_LINUX
virtual size_t GetUniqueId(char* id, size_t max_size) const override;
#endif
};
// mmap() based random-access
class PosixMmapReadableFile : public FSRandomAccessFile {
private:
int fd_;
std::string filename_;
void* mmapped_region_;
size_t length_;
public:
PosixMmapReadableFile(const int fd, const std::string& fname, void* base,
size_t length, const EnvOptions& options);
virtual ~PosixMmapReadableFile();
virtual IOStatus Read(uint64_t offset, size_t n, const IOOptions& opts,
Slice* result, char* scratch,
IODebugContext* dbg) const override;
virtual IOStatus InvalidateCache(size_t offset, size_t length) override;
};
class PosixMmapFile : public FSWritableFile {
private:
std::string filename_;
int fd_;
size_t page_size_;
size_t map_size_; // How much extra memory to map at a time
char* base_; // The mapped region
char* limit_; // Limit of the mapped region
char* dst_; // Where to write next (in range [base_,limit_])
char* last_sync_; // Where have we synced up to
uint64_t file_offset_; // Offset of base_ in file
#ifdef ROCKSDB_FALLOCATE_PRESENT
bool allow_fallocate_; // If false, fallocate calls are bypassed
bool fallocate_with_keep_size_;
#endif
// Roundup x to a multiple of y
static size_t Roundup(size_t x, size_t y) { return ((x + y - 1) / y) * y; }
size_t TruncateToPageBoundary(size_t s) {
s -= (s & (page_size_ - 1));
assert((s % page_size_) == 0);
return s;
}
IOStatus MapNewRegion();
IOStatus UnmapCurrentRegion();
IOStatus Msync();
public:
PosixMmapFile(const std::string& fname, int fd, size_t page_size,
const EnvOptions& options);
~PosixMmapFile();
// Means Close() will properly take care of truncate
// and it does not need any additional information
virtual IOStatus Truncate(uint64_t /*size*/, const IOOptions& /*opts*/,
IODebugContext* /*dbg*/) override {
return IOStatus::OK();
}
virtual IOStatus Close(const IOOptions& opts, IODebugContext* dbg) override;
virtual IOStatus Append(const Slice& data, const IOOptions& opts,
IODebugContext* dbg) override;
virtual IOStatus Append(const Slice& data, const IOOptions& opts,
const DataVerificationInfo& /* verification_info */,
IODebugContext* dbg) override {
return Append(data, opts, dbg);
}
virtual IOStatus Flush(const IOOptions& opts, IODebugContext* dbg) override;
virtual IOStatus Sync(const IOOptions& opts, IODebugContext* dbg) override;
virtual IOStatus Fsync(const IOOptions& opts, IODebugContext* dbg) override;
virtual uint64_t GetFileSize(const IOOptions& opts,
IODebugContext* dbg) override;
virtual IOStatus InvalidateCache(size_t offset, size_t length) override;
#ifdef ROCKSDB_FALLOCATE_PRESENT
virtual IOStatus Allocate(uint64_t offset, uint64_t len,
const IOOptions& opts,
IODebugContext* dbg) override;
#endif
};
class PosixRandomRWFile : public FSRandomRWFile {
public:
explicit PosixRandomRWFile(const std::string& fname, int fd,
const EnvOptions& options);
virtual ~PosixRandomRWFile();
virtual IOStatus Write(uint64_t offset, const Slice& data,
const IOOptions& opts, IODebugContext* dbg) override;
virtual IOStatus Read(uint64_t offset, size_t n, const IOOptions& opts,
Slice* result, char* scratch,
IODebugContext* dbg) const override;
virtual IOStatus Flush(const IOOptions& opts, IODebugContext* dbg) override;
virtual IOStatus Sync(const IOOptions& opts, IODebugContext* dbg) override;
virtual IOStatus Fsync(const IOOptions& opts, IODebugContext* dbg) override;
virtual IOStatus Close(const IOOptions& opts, IODebugContext* dbg) override;
private:
const std::string filename_;
int fd_;
};
struct PosixMemoryMappedFileBuffer : public MemoryMappedFileBuffer {
PosixMemoryMappedFileBuffer(void* _base, size_t _length)
: MemoryMappedFileBuffer(_base, _length) {}
virtual ~PosixMemoryMappedFileBuffer();
};
class PosixDirectory : public FSDirectory {
public:
explicit PosixDirectory(int fd);
~PosixDirectory();
virtual IOStatus Fsync(const IOOptions& opts, IODebugContext* dbg) override;
virtual IOStatus FsyncWithDirOptions(
const IOOptions&, IODebugContext*,
const DirFsyncOptions& dir_fsync_options) override;
private:
int fd_;
bool is_btrfs_;
};
} // namespace ROCKSDB_NAMESPACE