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rocksdb/env/fs_posix.cc

914 lines
28 KiB

Introduce a new storage specific Env API (#5761) Summary: The current Env API encompasses both storage/file operations, as well as OS related operations. Most of the APIs return a Status, which does not have enough metadata about an error, such as whether its retry-able or not, scope (i.e fault domain) of the error etc., that may be required in order to properly handle a storage error. The file APIs also do not provide enough control over the IO SLA, such as timeout, prioritization, hinting about placement and redundancy etc. This PR separates out the file/storage APIs from Env into a new FileSystem class. The APIs are updated to return an IOStatus with metadata about the error, as well as to take an IOOptions structure as input in order to allow more control over the IO. The user can set both ```options.env``` and ```options.file_system``` to specify that RocksDB should use the former for OS related operations and the latter for storage operations. Internally, a ```CompositeEnvWrapper``` has been introduced that inherits from ```Env``` and redirects individual methods to either an ```Env``` implementation or the ```FileSystem``` as appropriate. When options are sanitized during ```DB::Open```, ```options.env``` is replaced with a newly allocated ```CompositeEnvWrapper``` instance if both env and file_system have been specified. This way, the rest of the RocksDB code can continue to function as before. This PR also ports PosixEnv to the new API by splitting it into two - PosixEnv and PosixFileSystem. PosixEnv is defined as a sub-class of CompositeEnvWrapper, and threading/time functions are overridden with Posix specific implementations in order to avoid an extra level of indirection. The ```CompositeEnvWrapper``` translates ```IOStatus``` return code to ```Status```, and sets the severity to ```kSoftError``` if the io_status is retryable. The error handling code in RocksDB can then recover the DB automatically. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5761 Differential Revision: D18868376 Pulled By: anand1976 fbshipit-source-id: 39efe18a162ea746fabac6360ff529baba48486f
5 years ago
// 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
#include <dirent.h>
#ifndef ROCKSDB_NO_DYNAMIC_EXTENSION
#include <dlfcn.h>
#endif
#include <errno.h>
#include <fcntl.h>
#if defined(OS_LINUX)
#include <linux/fs.h>
#endif
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#if defined(OS_LINUX) || defined(OS_SOLARIS) || defined(OS_ANDROID)
#include <sys/statfs.h>
#include <sys/syscall.h>
#include <sys/sysmacros.h>
#endif
#include <sys/statvfs.h>
#include <sys/time.h>
#include <sys/types.h>
#include <time.h>
#include <algorithm>
// Get nano time includes
#if defined(OS_LINUX) || defined(OS_FREEBSD)
#elif defined(__MACH__)
#include <Availability.h>
#include <mach/clock.h>
#include <mach/mach.h>
#else
#include <chrono>
#endif
#include <deque>
#include <set>
#include <vector>
#include "env/io_posix.h"
#include "logging/logging.h"
#include "logging/posix_logger.h"
#include "monitoring/iostats_context_imp.h"
#include "monitoring/thread_status_updater.h"
#include "port/port.h"
#include "rocksdb/options.h"
#include "rocksdb/slice.h"
#include "test_util/sync_point.h"
#include "util/coding.h"
#include "util/compression_context_cache.h"
#include "util/random.h"
#include "util/string_util.h"
#include "util/thread_local.h"
#include "util/threadpool_imp.h"
#if !defined(TMPFS_MAGIC)
#define TMPFS_MAGIC 0x01021994
#endif
#if !defined(XFS_SUPER_MAGIC)
#define XFS_SUPER_MAGIC 0x58465342
#endif
#if !defined(EXT4_SUPER_MAGIC)
#define EXT4_SUPER_MAGIC 0xEF53
#endif
namespace ROCKSDB_NAMESPACE {
Introduce a new storage specific Env API (#5761) Summary: The current Env API encompasses both storage/file operations, as well as OS related operations. Most of the APIs return a Status, which does not have enough metadata about an error, such as whether its retry-able or not, scope (i.e fault domain) of the error etc., that may be required in order to properly handle a storage error. The file APIs also do not provide enough control over the IO SLA, such as timeout, prioritization, hinting about placement and redundancy etc. This PR separates out the file/storage APIs from Env into a new FileSystem class. The APIs are updated to return an IOStatus with metadata about the error, as well as to take an IOOptions structure as input in order to allow more control over the IO. The user can set both ```options.env``` and ```options.file_system``` to specify that RocksDB should use the former for OS related operations and the latter for storage operations. Internally, a ```CompositeEnvWrapper``` has been introduced that inherits from ```Env``` and redirects individual methods to either an ```Env``` implementation or the ```FileSystem``` as appropriate. When options are sanitized during ```DB::Open```, ```options.env``` is replaced with a newly allocated ```CompositeEnvWrapper``` instance if both env and file_system have been specified. This way, the rest of the RocksDB code can continue to function as before. This PR also ports PosixEnv to the new API by splitting it into two - PosixEnv and PosixFileSystem. PosixEnv is defined as a sub-class of CompositeEnvWrapper, and threading/time functions are overridden with Posix specific implementations in order to avoid an extra level of indirection. The ```CompositeEnvWrapper``` translates ```IOStatus``` return code to ```Status```, and sets the severity to ```kSoftError``` if the io_status is retryable. The error handling code in RocksDB can then recover the DB automatically. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5761 Differential Revision: D18868376 Pulled By: anand1976 fbshipit-source-id: 39efe18a162ea746fabac6360ff529baba48486f
5 years ago
namespace {
inline mode_t GetDBFileMode(bool allow_non_owner_access) {
return allow_non_owner_access ? 0644 : 0600;
}
// list of pathnames that are locked
static std::set<std::string> lockedFiles;
static port::Mutex mutex_lockedFiles;
static int LockOrUnlock(int fd, bool lock) {
errno = 0;
struct flock f;
memset(&f, 0, sizeof(f));
f.l_type = (lock ? F_WRLCK : F_UNLCK);
f.l_whence = SEEK_SET;
f.l_start = 0;
f.l_len = 0; // Lock/unlock entire file
int value = fcntl(fd, F_SETLK, &f);
return value;
}
class PosixFileLock : public FileLock {
public:
int fd_;
std::string filename;
};
int cloexec_flags(int flags, const EnvOptions* options) {
// If the system supports opening the file with cloexec enabled,
// do so, as this avoids a race condition if a db is opened around
// the same time that a child process is forked
#ifdef O_CLOEXEC
if (options == nullptr || options->set_fd_cloexec) {
flags |= O_CLOEXEC;
}
#endif
return flags;
}
class PosixFileSystem : public FileSystem {
public:
PosixFileSystem();
const char* Name() const override { return "Posix File System"; }
~PosixFileSystem() override {}
void SetFD_CLOEXEC(int fd, const EnvOptions* options) {
if ((options == nullptr || options->set_fd_cloexec) && fd > 0) {
fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
}
}
IOStatus NewSequentialFile(const std::string& fname,
const FileOptions& options,
std::unique_ptr<FSSequentialFile>* result,
IODebugContext* /*dbg*/) override {
result->reset();
int fd = -1;
int flags = cloexec_flags(O_RDONLY, &options);
FILE* file = nullptr;
if (options.use_direct_reads && !options.use_mmap_reads) {
#ifdef ROCKSDB_LITE
return IOStatus::IOError(fname,
"Direct I/O not supported in RocksDB lite");
#endif // !ROCKSDB_LITE
#if !defined(OS_MACOSX) && !defined(OS_OPENBSD) && !defined(OS_SOLARIS)
flags |= O_DIRECT;
#endif
}
do {
IOSTATS_TIMER_GUARD(open_nanos);
fd = open(fname.c_str(), flags, GetDBFileMode(allow_non_owner_access_));
} while (fd < 0 && errno == EINTR);
if (fd < 0) {
return IOError("While opening a file for sequentially reading", fname,
errno);
}
SetFD_CLOEXEC(fd, &options);
if (options.use_direct_reads && !options.use_mmap_reads) {
#ifdef OS_MACOSX
if (fcntl(fd, F_NOCACHE, 1) == -1) {
close(fd);
return IOError("While fcntl NoCache", fname, errno);
}
#endif
} else {
do {
IOSTATS_TIMER_GUARD(open_nanos);
file = fdopen(fd, "r");
} while (file == nullptr && errno == EINTR);
if (file == nullptr) {
close(fd);
return IOError("While opening file for sequentially read", fname,
errno);
}
}
result->reset(new PosixSequentialFile(fname, file, fd, options));
return IOStatus::OK();
}
IOStatus NewRandomAccessFile(const std::string& fname,
const FileOptions& options,
std::unique_ptr<FSRandomAccessFile>* result,
IODebugContext* /*dbg*/) override {
result->reset();
IOStatus s;
int fd;
int flags = cloexec_flags(O_RDONLY, &options);
if (options.use_direct_reads && !options.use_mmap_reads) {
#ifdef ROCKSDB_LITE
return IOStatus::IOError(fname,
"Direct I/O not supported in RocksDB lite");
#endif // !ROCKSDB_LITE
#if !defined(OS_MACOSX) && !defined(OS_OPENBSD) && !defined(OS_SOLARIS)
flags |= O_DIRECT;
TEST_SYNC_POINT_CALLBACK("NewRandomAccessFile:O_DIRECT", &flags);
#endif
}
do {
IOSTATS_TIMER_GUARD(open_nanos);
fd = open(fname.c_str(), flags, GetDBFileMode(allow_non_owner_access_));
} while (fd < 0 && errno == EINTR);
if (fd < 0) {
return IOError("While open a file for random read", fname, errno);
}
SetFD_CLOEXEC(fd, &options);
if (options.use_mmap_reads && sizeof(void*) >= 8) {
// Use of mmap for random reads has been removed because it
// kills performance when storage is fast.
// Use mmap when virtual address-space is plentiful.
uint64_t size;
IOOptions opts;
s = GetFileSize(fname, opts, &size, nullptr);
if (s.ok()) {
void* base = mmap(nullptr, size, PROT_READ, MAP_SHARED, fd, 0);
if (base != MAP_FAILED) {
result->reset(
new PosixMmapReadableFile(fd, fname, base, size, options));
} else {
s = IOError("while mmap file for read", fname, errno);
close(fd);
}
}
} else {
if (options.use_direct_reads && !options.use_mmap_reads) {
#ifdef OS_MACOSX
if (fcntl(fd, F_NOCACHE, 1) == -1) {
close(fd);
return IOError("while fcntl NoCache", fname, errno);
}
#endif
}
result->reset(new PosixRandomAccessFile(fname, fd, options
#if defined(ROCKSDB_IOURING_PRESENT)
,
thread_local_io_urings_.get()
#endif
));
}
return s;
}
virtual IOStatus OpenWritableFile(const std::string& fname,
const FileOptions& options,
bool reopen,
std::unique_ptr<FSWritableFile>* result,
IODebugContext* /*dbg*/) {
result->reset();
IOStatus s;
int fd = -1;
int flags = (reopen) ? (O_CREAT | O_APPEND) : (O_CREAT | O_TRUNC);
// Direct IO mode with O_DIRECT flag or F_NOCAHCE (MAC OSX)
if (options.use_direct_writes && !options.use_mmap_writes) {
// Note: we should avoid O_APPEND here due to ta the following bug:
// POSIX requires that opening a file with the O_APPEND flag should
// have no affect on the location at which pwrite() writes data.
// However, on Linux, if a file is opened with O_APPEND, pwrite()
// appends data to the end of the file, regardless of the value of
// offset.
// More info here: https://linux.die.net/man/2/pwrite
#ifdef ROCKSDB_LITE
return IOStatus::IOError(fname,
"Direct I/O not supported in RocksDB lite");
#endif // ROCKSDB_LITE
flags |= O_WRONLY;
#if !defined(OS_MACOSX) && !defined(OS_OPENBSD) && !defined(OS_SOLARIS)
flags |= O_DIRECT;
#endif
TEST_SYNC_POINT_CALLBACK("NewWritableFile:O_DIRECT", &flags);
} else if (options.use_mmap_writes) {
// non-direct I/O
flags |= O_RDWR;
} else {
flags |= O_WRONLY;
}
flags = cloexec_flags(flags, &options);
do {
IOSTATS_TIMER_GUARD(open_nanos);
fd = open(fname.c_str(), flags, GetDBFileMode(allow_non_owner_access_));
} while (fd < 0 && errno == EINTR);
if (fd < 0) {
s = IOError("While open a file for appending", fname, errno);
return s;
}
SetFD_CLOEXEC(fd, &options);
if (options.use_mmap_writes) {
if (!checkedDiskForMmap_) {
// this will be executed once in the program's lifetime.
// do not use mmapWrite on non ext-3/xfs/tmpfs systems.
if (!SupportsFastAllocate(fname)) {
forceMmapOff_ = true;
}
checkedDiskForMmap_ = true;
}
}
if (options.use_mmap_writes && !forceMmapOff_) {
result->reset(new PosixMmapFile(fname, fd, page_size_, options));
} else if (options.use_direct_writes && !options.use_mmap_writes) {
#ifdef OS_MACOSX
if (fcntl(fd, F_NOCACHE, 1) == -1) {
close(fd);
s = IOError("While fcntl NoCache an opened file for appending", fname,
errno);
return s;
}
#elif defined(OS_SOLARIS)
if (directio(fd, DIRECTIO_ON) == -1) {
if (errno != ENOTTY) { // ZFS filesystems don't support DIRECTIO_ON
close(fd);
s = IOError("While calling directio()", fname, errno);
return s;
}
}
#endif
result->reset(new PosixWritableFile(fname, fd, options));
} else {
// disable mmap writes
EnvOptions no_mmap_writes_options = options;
no_mmap_writes_options.use_mmap_writes = false;
result->reset(new PosixWritableFile(fname, fd, no_mmap_writes_options));
}
return s;
}
IOStatus NewWritableFile(const std::string& fname, const FileOptions& options,
std::unique_ptr<FSWritableFile>* result,
IODebugContext* dbg) override {
return OpenWritableFile(fname, options, false, result, dbg);
}
IOStatus ReopenWritableFile(const std::string& fname,
const FileOptions& options,
std::unique_ptr<FSWritableFile>* result,
IODebugContext* dbg) override {
return OpenWritableFile(fname, options, true, result, dbg);
}
IOStatus ReuseWritableFile(const std::string& fname,
const std::string& old_fname,
const FileOptions& options,
std::unique_ptr<FSWritableFile>* result,
IODebugContext* /*dbg*/) override {
result->reset();
IOStatus s;
int fd = -1;
int flags = 0;
// Direct IO mode with O_DIRECT flag or F_NOCAHCE (MAC OSX)
if (options.use_direct_writes && !options.use_mmap_writes) {
#ifdef ROCKSDB_LITE
return IOStatus::IOError(fname,
"Direct I/O not supported in RocksDB lite");
#endif // !ROCKSDB_LITE
flags |= O_WRONLY;
#if !defined(OS_MACOSX) && !defined(OS_OPENBSD) && !defined(OS_SOLARIS)
flags |= O_DIRECT;
#endif
TEST_SYNC_POINT_CALLBACK("NewWritableFile:O_DIRECT", &flags);
} else if (options.use_mmap_writes) {
// mmap needs O_RDWR mode
flags |= O_RDWR;
} else {
flags |= O_WRONLY;
}
flags = cloexec_flags(flags, &options);
do {
IOSTATS_TIMER_GUARD(open_nanos);
fd = open(old_fname.c_str(), flags,
GetDBFileMode(allow_non_owner_access_));
} while (fd < 0 && errno == EINTR);
if (fd < 0) {
s = IOError("while reopen file for write", fname, errno);
return s;
}
SetFD_CLOEXEC(fd, &options);
// rename into place
if (rename(old_fname.c_str(), fname.c_str()) != 0) {
s = IOError("while rename file to " + fname, old_fname, errno);
close(fd);
return s;
}
if (options.use_mmap_writes) {
if (!checkedDiskForMmap_) {
// this will be executed once in the program's lifetime.
// do not use mmapWrite on non ext-3/xfs/tmpfs systems.
if (!SupportsFastAllocate(fname)) {
forceMmapOff_ = true;
}
checkedDiskForMmap_ = true;
}
}
if (options.use_mmap_writes && !forceMmapOff_) {
result->reset(new PosixMmapFile(fname, fd, page_size_, options));
} else if (options.use_direct_writes && !options.use_mmap_writes) {
#ifdef OS_MACOSX
if (fcntl(fd, F_NOCACHE, 1) == -1) {
close(fd);
s = IOError("while fcntl NoCache for reopened file for append", fname,
errno);
return s;
}
#elif defined(OS_SOLARIS)
if (directio(fd, DIRECTIO_ON) == -1) {
if (errno != ENOTTY) { // ZFS filesystems don't support DIRECTIO_ON
close(fd);
s = IOError("while calling directio()", fname, errno);
return s;
}
}
#endif
result->reset(new PosixWritableFile(fname, fd, options));
} else {
// disable mmap writes
FileOptions no_mmap_writes_options = options;
no_mmap_writes_options.use_mmap_writes = false;
result->reset(new PosixWritableFile(fname, fd, no_mmap_writes_options));
}
return s;
}
IOStatus NewRandomRWFile(const std::string& fname, const FileOptions& options,
std::unique_ptr<FSRandomRWFile>* result,
IODebugContext* /*dbg*/) override {
int fd = -1;
int flags = cloexec_flags(O_RDWR, &options);
while (fd < 0) {
IOSTATS_TIMER_GUARD(open_nanos);
fd = open(fname.c_str(), flags, GetDBFileMode(allow_non_owner_access_));
if (fd < 0) {
// Error while opening the file
if (errno == EINTR) {
continue;
}
return IOError("While open file for random read/write", fname, errno);
}
}
SetFD_CLOEXEC(fd, &options);
result->reset(new PosixRandomRWFile(fname, fd, options));
return IOStatus::OK();
}
IOStatus NewMemoryMappedFileBuffer(
const std::string& fname,
std::unique_ptr<MemoryMappedFileBuffer>* result) override {
int fd = -1;
IOStatus status;
int flags = cloexec_flags(O_RDWR, nullptr);
while (fd < 0) {
IOSTATS_TIMER_GUARD(open_nanos);
fd = open(fname.c_str(), flags, 0644);
if (fd < 0) {
// Error while opening the file
if (errno == EINTR) {
continue;
}
status =
IOError("While open file for raw mmap buffer access", fname, errno);
break;
}
}
uint64_t size;
if (status.ok()) {
IOOptions opts;
status = GetFileSize(fname, opts, &size, nullptr);
}
void* base = nullptr;
if (status.ok()) {
base = mmap(nullptr, static_cast<size_t>(size), PROT_READ | PROT_WRITE,
MAP_SHARED, fd, 0);
if (base == MAP_FAILED) {
status = IOError("while mmap file for read", fname, errno);
}
}
if (status.ok()) {
result->reset(
new PosixMemoryMappedFileBuffer(base, static_cast<size_t>(size)));
}
if (fd >= 0) {
// don't need to keep it open after mmap has been called
close(fd);
}
return status;
}
IOStatus NewDirectory(const std::string& name, const IOOptions& /*opts*/,
std::unique_ptr<FSDirectory>* result,
IODebugContext* /*dbg*/) override {
result->reset();
int fd;
int flags = cloexec_flags(0, nullptr);
{
IOSTATS_TIMER_GUARD(open_nanos);
fd = open(name.c_str(), flags);
}
if (fd < 0) {
return IOError("While open directory", name, errno);
} else {
result->reset(new PosixDirectory(fd));
}
return IOStatus::OK();
}
IOStatus NewLogger(const std::string& /*fname*/, const IOOptions& /*opts*/,
std::shared_ptr<ROCKSDB_NAMESPACE::Logger>* /*ptr*/,
Introduce a new storage specific Env API (#5761) Summary: The current Env API encompasses both storage/file operations, as well as OS related operations. Most of the APIs return a Status, which does not have enough metadata about an error, such as whether its retry-able or not, scope (i.e fault domain) of the error etc., that may be required in order to properly handle a storage error. The file APIs also do not provide enough control over the IO SLA, such as timeout, prioritization, hinting about placement and redundancy etc. This PR separates out the file/storage APIs from Env into a new FileSystem class. The APIs are updated to return an IOStatus with metadata about the error, as well as to take an IOOptions structure as input in order to allow more control over the IO. The user can set both ```options.env``` and ```options.file_system``` to specify that RocksDB should use the former for OS related operations and the latter for storage operations. Internally, a ```CompositeEnvWrapper``` has been introduced that inherits from ```Env``` and redirects individual methods to either an ```Env``` implementation or the ```FileSystem``` as appropriate. When options are sanitized during ```DB::Open```, ```options.env``` is replaced with a newly allocated ```CompositeEnvWrapper``` instance if both env and file_system have been specified. This way, the rest of the RocksDB code can continue to function as before. This PR also ports PosixEnv to the new API by splitting it into two - PosixEnv and PosixFileSystem. PosixEnv is defined as a sub-class of CompositeEnvWrapper, and threading/time functions are overridden with Posix specific implementations in order to avoid an extra level of indirection. The ```CompositeEnvWrapper``` translates ```IOStatus``` return code to ```Status```, and sets the severity to ```kSoftError``` if the io_status is retryable. The error handling code in RocksDB can then recover the DB automatically. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5761 Differential Revision: D18868376 Pulled By: anand1976 fbshipit-source-id: 39efe18a162ea746fabac6360ff529baba48486f
5 years ago
IODebugContext* /*dbg*/) override {
return IOStatus::NotSupported();
}
IOStatus FileExists(const std::string& fname, const IOOptions& /*opts*/,
IODebugContext* /*dbg*/) override {
int result = access(fname.c_str(), F_OK);
if (result == 0) {
return IOStatus::OK();
}
int err = errno;
switch (err) {
case EACCES:
case ELOOP:
case ENAMETOOLONG:
case ENOENT:
case ENOTDIR:
return IOStatus::NotFound();
default:
assert(err == EIO || err == ENOMEM);
return IOStatus::IOError("Unexpected error(" + ToString(err) +
") accessing file `" + fname + "' ");
}
}
IOStatus GetChildren(const std::string& dir, const IOOptions& /*opts*/,
std::vector<std::string>* result,
IODebugContext* /*dbg*/) override {
result->clear();
DIR* d = opendir(dir.c_str());
if (d == nullptr) {
switch (errno) {
case EACCES:
case ENOENT:
case ENOTDIR:
return IOStatus::NotFound();
default:
return IOError("While opendir", dir, errno);
}
}
struct dirent* entry;
while ((entry = readdir(d)) != nullptr) {
result->push_back(entry->d_name);
}
closedir(d);
return IOStatus::OK();
}
IOStatus DeleteFile(const std::string& fname, const IOOptions& /*opts*/,
IODebugContext* /*dbg*/) override {
IOStatus result;
if (unlink(fname.c_str()) != 0) {
result = IOError("while unlink() file", fname, errno);
}
return result;
}
IOStatus CreateDir(const std::string& name, const IOOptions& /*opts*/,
IODebugContext* /*dbg*/) override {
IOStatus result;
if (mkdir(name.c_str(), 0755) != 0) {
result = IOError("While mkdir", name, errno);
}
return result;
}
IOStatus CreateDirIfMissing(const std::string& name,
const IOOptions& /*opts*/,
IODebugContext* /*dbg*/) override {
IOStatus result;
if (mkdir(name.c_str(), 0755) != 0) {
if (errno != EEXIST) {
result = IOError("While mkdir if missing", name, errno);
} else if (!DirExists(name)) { // Check that name is actually a
// directory.
// Message is taken from mkdir
result =
IOStatus::IOError("`" + name + "' exists but is not a directory");
}
}
return result;
}
IOStatus DeleteDir(const std::string& name, const IOOptions& /*opts*/,
IODebugContext* /*dbg*/) override {
IOStatus result;
if (rmdir(name.c_str()) != 0) {
result = IOError("file rmdir", name, errno);
}
return result;
}
IOStatus GetFileSize(const std::string& fname, const IOOptions& /*opts*/,
uint64_t* size, IODebugContext* /*dbg*/) override {
IOStatus s;
struct stat sbuf;
if (stat(fname.c_str(), &sbuf) != 0) {
*size = 0;
s = IOError("while stat a file for size", fname, errno);
} else {
*size = sbuf.st_size;
}
return s;
}
IOStatus GetFileModificationTime(const std::string& fname,
const IOOptions& /*opts*/,
uint64_t* file_mtime,
IODebugContext* /*dbg*/) override {
struct stat s;
if (stat(fname.c_str(), &s) != 0) {
return IOError("while stat a file for modification time", fname, errno);
}
*file_mtime = static_cast<uint64_t>(s.st_mtime);
return IOStatus::OK();
}
IOStatus RenameFile(const std::string& src, const std::string& target,
const IOOptions& /*opts*/,
IODebugContext* /*dbg*/) override {
IOStatus result;
if (rename(src.c_str(), target.c_str()) != 0) {
result = IOError("While renaming a file to " + target, src, errno);
}
return result;
}
IOStatus LinkFile(const std::string& src, const std::string& target,
const IOOptions& /*opts*/,
IODebugContext* /*dbg*/) override {
IOStatus result;
if (link(src.c_str(), target.c_str()) != 0) {
if (errno == EXDEV) {
return IOStatus::NotSupported("No cross FS links allowed");
}
result = IOError("while link file to " + target, src, errno);
}
return result;
}
IOStatus NumFileLinks(const std::string& fname, const IOOptions& /*opts*/,
uint64_t* count, IODebugContext* /*dbg*/) override {
struct stat s;
if (stat(fname.c_str(), &s) != 0) {
return IOError("while stat a file for num file links", fname, errno);
}
*count = static_cast<uint64_t>(s.st_nlink);
return IOStatus::OK();
}
IOStatus AreFilesSame(const std::string& first, const std::string& second,
const IOOptions& /*opts*/, bool* res,
IODebugContext* /*dbg*/) override {
struct stat statbuf[2];
if (stat(first.c_str(), &statbuf[0]) != 0) {
return IOError("stat file", first, errno);
}
if (stat(second.c_str(), &statbuf[1]) != 0) {
return IOError("stat file", second, errno);
}
if (major(statbuf[0].st_dev) != major(statbuf[1].st_dev) ||
minor(statbuf[0].st_dev) != minor(statbuf[1].st_dev) ||
statbuf[0].st_ino != statbuf[1].st_ino) {
*res = false;
} else {
*res = true;
}
return IOStatus::OK();
}
IOStatus LockFile(const std::string& fname, const IOOptions& /*opts*/,
FileLock** lock, IODebugContext* /*dbg*/) override {
*lock = nullptr;
IOStatus result;
mutex_lockedFiles.Lock();
// If it already exists in the lockedFiles set, then it is already locked,
// and fail this lock attempt. Otherwise, insert it into lockedFiles.
// This check is needed because fcntl() does not detect lock conflict
// if the fcntl is issued by the same thread that earlier acquired
// this lock.
// We must do this check *before* opening the file:
// Otherwise, we will open a new file descriptor. Locks are associated with
// a process, not a file descriptor and when *any* file descriptor is
// closed, all locks the process holds for that *file* are released
if (lockedFiles.insert(fname).second == false) {
mutex_lockedFiles.Unlock();
errno = ENOLCK;
return IOError("lock ", fname, errno);
}
int fd;
int flags = cloexec_flags(O_RDWR | O_CREAT, nullptr);
{
IOSTATS_TIMER_GUARD(open_nanos);
fd = open(fname.c_str(), flags, 0644);
}
if (fd < 0) {
result = IOError("while open a file for lock", fname, errno);
} else if (LockOrUnlock(fd, true) == -1) {
// if there is an error in locking, then remove the pathname from
// lockedfiles
lockedFiles.erase(fname);
result = IOError("While lock file", fname, errno);
close(fd);
} else {
SetFD_CLOEXEC(fd, nullptr);
PosixFileLock* my_lock = new PosixFileLock;
my_lock->fd_ = fd;
my_lock->filename = fname;
*lock = my_lock;
}
mutex_lockedFiles.Unlock();
return result;
}
IOStatus UnlockFile(FileLock* lock, const IOOptions& /*opts*/,
IODebugContext* /*dbg*/) override {
PosixFileLock* my_lock = reinterpret_cast<PosixFileLock*>(lock);
IOStatus result;
mutex_lockedFiles.Lock();
// If we are unlocking, then verify that we had locked it earlier,
// it should already exist in lockedFiles. Remove it from lockedFiles.
if (lockedFiles.erase(my_lock->filename) != 1) {
errno = ENOLCK;
result = IOError("unlock", my_lock->filename, errno);
} else if (LockOrUnlock(my_lock->fd_, false) == -1) {
result = IOError("unlock", my_lock->filename, errno);
}
close(my_lock->fd_);
delete my_lock;
mutex_lockedFiles.Unlock();
return result;
}
IOStatus GetAbsolutePath(const std::string& db_path,
const IOOptions& /*opts*/, std::string* output_path,
IODebugContext* /*dbg*/) override {
if (!db_path.empty() && db_path[0] == '/') {
*output_path = db_path;
return IOStatus::OK();
}
char the_path[256];
char* ret = getcwd(the_path, 256);
if (ret == nullptr) {
return IOStatus::IOError(strerror(errno));
}
*output_path = ret;
return IOStatus::OK();
}
IOStatus GetTestDirectory(const IOOptions& /*opts*/, std::string* result,
IODebugContext* /*dbg*/) override {
const char* env = getenv("TEST_TMPDIR");
if (env && env[0] != '\0') {
*result = env;
} else {
char buf[100];
snprintf(buf, sizeof(buf), "/tmp/rocksdbtest-%d", int(geteuid()));
*result = buf;
}
// Directory may already exist
{
IOOptions opts;
CreateDir(*result, opts, nullptr);
}
return IOStatus::OK();
}
IOStatus GetFreeSpace(const std::string& fname, const IOOptions& /*opts*/,
uint64_t* free_space,
IODebugContext* /*dbg*/) override {
struct statvfs sbuf;
if (statvfs(fname.c_str(), &sbuf) < 0) {
return IOError("While doing statvfs", fname, errno);
}
*free_space = ((uint64_t)sbuf.f_bsize * sbuf.f_bfree);
return IOStatus::OK();
}
FileOptions OptimizeForLogWrite(const FileOptions& file_options,
const DBOptions& db_options) const override {
FileOptions optimized = file_options;
optimized.use_mmap_writes = false;
optimized.use_direct_writes = false;
optimized.bytes_per_sync = db_options.wal_bytes_per_sync;
// TODO(icanadi) it's faster if fallocate_with_keep_size is false, but it
// breaks TransactionLogIteratorStallAtLastRecord unit test. Fix the unit
// test and make this false
optimized.fallocate_with_keep_size = true;
optimized.writable_file_max_buffer_size =
db_options.writable_file_max_buffer_size;
return optimized;
}
FileOptions OptimizeForManifestWrite(
const FileOptions& file_options) const override {
FileOptions optimized = file_options;
optimized.use_mmap_writes = false;
optimized.use_direct_writes = false;
optimized.fallocate_with_keep_size = true;
return optimized;
}
private:
bool checkedDiskForMmap_;
bool forceMmapOff_; // do we override Env options?
// Returns true iff the named directory exists and is a directory.
virtual bool DirExists(const std::string& dname) {
struct stat statbuf;
if (stat(dname.c_str(), &statbuf) == 0) {
return S_ISDIR(statbuf.st_mode);
}
return false; // stat() failed return false
}
bool SupportsFastAllocate(const std::string& path) {
#ifdef ROCKSDB_FALLOCATE_PRESENT
struct statfs s;
if (statfs(path.c_str(), &s)) {
return false;
}
switch (s.f_type) {
case EXT4_SUPER_MAGIC:
return true;
case XFS_SUPER_MAGIC:
return true;
case TMPFS_MAGIC:
return true;
default:
return false;
}
#else
(void)path;
return false;
#endif
}
#if defined(ROCKSDB_IOURING_PRESENT)
// io_uring instance
std::unique_ptr<ThreadLocalPtr> thread_local_io_urings_;
#endif
size_t page_size_;
// If true, allow non owner read access for db files. Otherwise, non-owner
// has no access to db files.
bool allow_non_owner_access_;
};
PosixFileSystem::PosixFileSystem()
: checkedDiskForMmap_(false),
forceMmapOff_(false),
page_size_(getpagesize()),
allow_non_owner_access_(true) {
#if defined(ROCKSDB_IOURING_PRESENT)
// Test whether IOUring is supported, and if it does, create a managing
// object for thread local point so that in the future thread-local
// io_uring can be created.
struct io_uring* new_io_uring = CreateIOUring();
if (new_io_uring != nullptr) {
thread_local_io_urings_.reset(new ThreadLocalPtr(DeleteIOUring));
delete new_io_uring;
}
#endif
}
} // namespace
//
// Default Posix FileSystem
//
std::shared_ptr<FileSystem> FileSystem::Default() {
static PosixFileSystem default_fs;
static std::shared_ptr<PosixFileSystem> default_fs_ptr(
&default_fs, [](PosixFileSystem*) {});
return default_fs_ptr;
}
} // namespace ROCKSDB_NAMESPACE