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rocksdb/env/io_posix.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 <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 "test_util/sync_point.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);
};
/*
* DirectIOHelper
*/
inline bool IsSectorAligned(const size_t off, size_t sector_size) {
assert((sector_size & (sector_size - 1)) == 0);
return (off & (sector_size - 1)) == 0;
}
#ifndef NDEBUG
inline bool IsSectorAligned(const void* ptr, size_t sector_size) {
return uintptr_t(ptr) % sector_size == 0;
}
#endif
#if defined(ROCKSDB_IOURING_PRESENT)
struct Posix_IOHandle {
Posix_IOHandle(struct io_uring* _iu,
std::function<void(const FSReadRequest&, void*)> _cb,
void* _cb_arg, uint64_t _offset, size_t _len, char* _scratch,
bool _use_direct_io, size_t _alignment)
: iu(_iu),
cb(_cb),
cb_arg(_cb_arg),
offset(_offset),
len(_len),
scratch(_scratch),
use_direct_io(_use_direct_io),
alignment(_alignment),
is_finished(false),
req_count(0) {}
struct iovec iov;
struct io_uring* iu;
std::function<void(const FSReadRequest&, void*)> cb;
void* cb_arg;
uint64_t offset;
size_t len;
char* scratch;
bool use_direct_io;
size_t alignment;
bool is_finished;
// req_count is used by AbortIO API to keep track of number of requests.
uint32_t req_count;
};
inline void UpdateResult(struct io_uring_cqe* cqe, const std::string& file_name,
size_t len, size_t iov_len, bool async_read,
bool use_direct_io, size_t alignment,
size_t& finished_len, FSReadRequest* req,
size_t& bytes_read, bool& read_again) {
read_again = false;
if (cqe->res < 0) {
req->result = Slice(req->scratch, 0);
req->status = IOError("Req failed", file_name, cqe->res);
} else {
bytes_read = static_cast<size_t>(cqe->res);
TEST_SYNC_POINT_CALLBACK("UpdateResults::io_uring_result", &bytes_read);
if (bytes_read == iov_len) {
req->result = Slice(req->scratch, req->len);
req->status = IOStatus::OK();
} else if (bytes_read == 0) {
/// cqe->res == 0 can means EOF, or can mean partial results. See
// comment
// https://github.com/facebook/rocksdb/pull/6441#issuecomment-589843435
// Fall back to pread in this case.
if (use_direct_io && !IsSectorAligned(finished_len, alignment)) {
// Bytes reads don't fill sectors. Should only happen at the end
// of the file.
req->result = Slice(req->scratch, finished_len);
req->status = IOStatus::OK();
} else {
if (async_read) {
// No bytes read. It can means EOF. In case of partial results, it's
// caller responsibility to call read/readasync again.
req->result = Slice(req->scratch, 0);
req->status = IOStatus::OK();
} else {
read_again = true;
}
}
} else if (bytes_read < iov_len) {
assert(bytes_read > 0);
if (async_read) {
req->result = Slice(req->scratch, bytes_read);
req->status = IOStatus::OK();
} else {
assert(bytes_read + finished_len < len);
finished_len += bytes_read;
}
} else {
req->result = Slice(req->scratch, 0);
req->status = IOError("Req returned more bytes than requested", file_name,
cqe->res);
}
}
#ifdef NDEBUG
(void)len;
#endif
}
#endif
#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_;
}
// EXPERIMENTAL
virtual IOStatus ReadAsync(
FSReadRequest& req, const IOOptions& opts,
std::function<void(const FSReadRequest&, void*)> cb, void* cb_arg,
void** io_handle, IOHandleDeleter* del_fn, IODebugContext* dbg) override;
};
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();
IOStatus Read(uint64_t offset, size_t n, const IOOptions& opts, Slice* result,
char* scratch, IODebugContext* dbg) const override;
void Hint(AccessPattern pattern) override;
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, const std::string& directory_name);
~PosixDirectory();
virtual IOStatus Fsync(const IOOptions& opts, IODebugContext* dbg) override;
virtual IOStatus Close(const IOOptions& opts, IODebugContext* dbg) override;
virtual IOStatus FsyncWithDirOptions(
const IOOptions&, IODebugContext*,
const DirFsyncOptions& dir_fsync_options) override;
private:
int fd_;
bool is_btrfs_;
const std::string directory_name_;
};
} // namespace ROCKSDB_NAMESPACE