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rocksdb/env/fs_posix.cc

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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
#if !defined(OS_WIN)
#include <dirent.h>
#ifndef ROCKSDB_NO_DYNAMIC_EXTENSION
#include <dlfcn.h>
#endif
#include <errno.h>
#include <fcntl.h>
#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/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/composite_env_wrapper.h"
#include "env/io_posix.h"
#include "monitoring/iostats_context_imp.h"
#include "monitoring/thread_status_updater.h"
#include "port/lang.h"
#include "port/port.h"
#include "rocksdb/options.h"
#include "rocksdb/slice.h"
#include "rocksdb/utilities/object_registry.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
extern "C" bool RocksDbIOUringEnable() __attribute__((__weak__));
namespace ROCKSDB_NAMESPACE {
namespace {
inline mode_t GetDBFileMode(bool allow_non_owner_access) {
return allow_non_owner_access ? 0644 : 0600;
}
// list of pathnames that are locked
// Only used for error message.
struct LockHoldingInfo {
int64_t acquire_time;
uint64_t acquiring_thread;
};
static std::map<std::string, LockHoldingInfo> locked_files;
static port::Mutex mutex_locked_files;
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_ = /*invalid*/ -1;
std::string filename;
void Clear() {
fd_ = -1;
filename.clear();
}
virtual ~PosixFileLock() override {
// Check for destruction without UnlockFile
assert(fd_ == -1);
}
};
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;
}
#else
(void)options;
#endif
return flags;
}
class PosixFileSystem : public FileSystem {
public:
PosixFileSystem();
static const char* kClassName() { return "PosixFileSystem"; }
const char* Name() const override { return kClassName(); }
const char* NickName() const override { return kDefaultName(); }
~PosixFileSystem() override {}
bool IsInstanceOf(const std::string& name) const override {
if (name == "posix") {
return true;
} else {
return FileSystem::IsInstanceOf(name);
}
}
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;
TEST_SYNC_POINT_CALLBACK("NewSequentialFile: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 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, GetLogicalBlockSizeForReadIfNeeded(options, fname, 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 = IOStatus::OK();
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) {
s = IOError("While open a file for random read", fname, errno);
return s;
}
SetFD_CLOEXEC(fd, &options);
if (options.use_mmap_reads) {
// 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 {
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, GetLogicalBlockSizeForReadIfNeeded(options, fname, fd),
options
#if defined(ROCKSDB_IOURING_PRESENT)
,
!IsIOUringEnabled() ? nullptr : 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) {
MaybeForceDisableMmap(fd);
}
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, GetLogicalBlockSizeForWriteIfNeeded(options, 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,
GetLogicalBlockSizeForWriteIfNeeded(
no_mmap_writes_options, 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) {
MaybeForceDisableMmap(fd);
}
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, GetLogicalBlockSizeForWriteIfNeeded(options, 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,
GetLogicalBlockSizeForWriteIfNeeded(
no_mmap_writes_options, 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, name));
}
return IOStatus::OK();
}
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(" + std::to_string(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);
}
}
// reset errno before calling readdir()
errno = 0;
struct dirent* entry;
while ((entry = readdir(d)) != nullptr) {
// filter out '.' and '..' directory entries
// which appear only on some platforms
const bool ignore =
entry->d_type == DT_DIR &&
(strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0);
if (!ignore) {
result->push_back(entry->d_name);
}
errno = 0; // reset errno if readdir() success
}
// always attempt to close the dir
const auto pre_close_errno = errno; // errno may be modified by closedir
const int close_result = closedir(d);
if (pre_close_errno != 0) {
// error occurred during readdir
return IOError("While readdir", dir, pre_close_errno);
}
if (close_result != 0) {
// error occurred during closedir
return IOError("While closedir", dir, errno);
}
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 {
if (mkdir(name.c_str(), 0755) != 0) {
return IOError("While mkdir", name, errno);
}
return IOStatus::OK();
}
IOStatus CreateDirIfMissing(const std::string& name,
const IOOptions& /*opts*/,
IODebugContext* /*dbg*/) override {
if (mkdir(name.c_str(), 0755) != 0) {
if (errno != EEXIST) {
return IOError("While mkdir if missing", name, errno);
} else if (!DirExists(name)) { // Check that name is actually a
// directory.
// Message is taken from mkdir
return IOStatus::IOError("`" + name +
"' exists but is not a directory");
}
}
return IOStatus::OK();
}
IOStatus DeleteDir(const std::string& name, const IOOptions& /*opts*/,
IODebugContext* /*dbg*/) override {
if (rmdir(name.c_str()) != 0) {
return IOError("file rmdir", name, errno);
}
return IOStatus::OK();
}
IOStatus GetFileSize(const std::string& fname, const IOOptions& /*opts*/,
uint64_t* size, IODebugContext* /*dbg*/) override {
struct stat sbuf;
if (stat(fname.c_str(), &sbuf) != 0) {
*size = 0;
return IOError("while stat a file for size", fname, errno);
} else {
*size = sbuf.st_size;
}
return IOStatus::OK();
}
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 {
if (rename(src.c_str(), target.c_str()) != 0) {
return IOError("While renaming a file to " + target, src, errno);
}
return IOStatus::OK();
}
IOStatus LinkFile(const std::string& src, const std::string& target,
const IOOptions& /*opts*/,
IODebugContext* /*dbg*/) override {
if (link(src.c_str(), target.c_str()) != 0) {
if (errno == EXDEV || errno == ENOTSUP) {
return IOStatus::NotSupported(errno == EXDEV
? "No cross FS links allowed"
: "Links not supported by FS");
}
return IOError("while link file to " + target, src, errno);
}
return IOStatus::OK();
}
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;
LockHoldingInfo lhi;
int64_t current_time = 0;
// Ignore status code as the time is only used for error message.
SystemClock::Default()
->GetCurrentTime(&current_time)
.PermitUncheckedError();
lhi.acquire_time = current_time;
lhi.acquiring_thread = Env::Default()->GetThreadID();
mutex_locked_files.Lock();
// If it already exists in the locked_files set, then it is already locked,
// and fail this lock attempt. Otherwise, insert it into locked_files.
// 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
const auto it_success = locked_files.insert({fname, lhi});
if (it_success.second == false) {
LockHoldingInfo prev_info = it_success.first->second;
mutex_locked_files.Unlock();
errno = ENOLCK;
// Note that the thread ID printed is the same one as the one in
// posix logger, but posix logger prints it hex format.
return IOError("lock hold by current process, acquire time " +
std::to_string(prev_info.acquire_time) +
" acquiring thread " +
std::to_string(prev_info.acquiring_thread),
fname, errno);
}
IOStatus result = IOStatus::OK();
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) {
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;
}
if (!result.ok()) {
// If there is an error in locking, then remove the pathname from
// locked_files. (If we got this far, it did not exist in locked_files
// before this call.)
locked_files.erase(fname);
}
mutex_locked_files.Unlock();
return result;
}
IOStatus UnlockFile(FileLock* lock, const IOOptions& /*opts*/,
IODebugContext* /*dbg*/) override {
PosixFileLock* my_lock = reinterpret_cast<PosixFileLock*>(lock);
IOStatus result;
mutex_locked_files.Lock();
// If we are unlocking, then verify that we had locked it earlier,
// it should already exist in locked_files. Remove it from locked_files.
if (locked_files.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_);
my_lock->Clear();
delete my_lock;
mutex_locked_files.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[4096];
char* ret = getcwd(the_path, 4096);
if (ret == nullptr) {
return IOStatus::IOError(errnoStr(errno).c_str());
}
*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;
return CreateDirIfMissing(*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);
}
// sbuf.bfree is total free space available to root
// sbuf.bavail is total free space available to unprivileged user
// sbuf.bavail <= sbuf.bfree ... pick correct based upon effective user id
if (geteuid()) {
// non-zero user is unprivileged, or -1 if error. take more conservative
// size
*free_space = ((uint64_t)sbuf.f_bsize * sbuf.f_bavail);
} else {
// root user can access all disk space
*free_space = ((uint64_t)sbuf.f_bsize * sbuf.f_bfree);
}
return IOStatus::OK();
}
IOStatus IsDirectory(const std::string& path, const IOOptions& /*opts*/,
bool* is_dir, IODebugContext* /*dbg*/) override {
// First open
int fd = -1;
int flags = cloexec_flags(O_RDONLY, nullptr);
{
IOSTATS_TIMER_GUARD(open_nanos);
fd = open(path.c_str(), flags);
}
if (fd < 0) {
return IOError("While open for IsDirectory()", path, errno);
}
IOStatus io_s;
struct stat sbuf;
if (fstat(fd, &sbuf) < 0) {
io_s = IOError("While doing stat for IsDirectory()", path, errno);
}
close(fd);
if (io_s.ok() && nullptr != is_dir) {
*is_dir = S_ISDIR(sbuf.st_mode);
}
return io_s;
}
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;
}
#ifdef OS_LINUX
Status RegisterDbPaths(const std::vector<std::string>& paths) override {
return logical_block_size_cache_.RefAndCacheLogicalBlockSize(paths);
}
Status UnregisterDbPaths(const std::vector<std::string>& paths) override {
logical_block_size_cache_.UnrefAndTryRemoveCachedLogicalBlockSize(paths);
return Status::OK();
}
#endif
private:
bool forceMmapOff_ = false; // 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(int fd) {
#ifdef ROCKSDB_FALLOCATE_PRESENT
struct statfs s;
if (fstatfs(fd, &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)fd;
return false;
#endif
}
void MaybeForceDisableMmap(int fd) {
static std::once_flag s_check_disk_for_mmap_once;
assert(this == FileSystem::Default().get());
std::call_once(
s_check_disk_for_mmap_once,
[this](int fdesc) {
// this will be executed once in the program's lifetime.
// do not use mmapWrite on non ext-3/xfs/tmpfs systems.
if (!SupportsFastAllocate(fdesc)) {
forceMmapOff_ = true;
}
},
fd);
}
#ifdef ROCKSDB_IOURING_PRESENT
bool IsIOUringEnabled() {
if (RocksDbIOUringEnable && RocksDbIOUringEnable()) {
return true;
} else {
return false;
}
}
#endif // ROCKSDB_IOURING_PRESENT
// EXPERIMENTAL
//
// TODO akankshamahajan:
// 1. Update Poll API to take into account min_completions
// and returns if number of handles in io_handles (any order) completed is
// equal to atleast min_completions.
// 2. Currently in case of direct_io, Read API is called because of which call
// to Poll API fails as it expects IOHandle to be populated.
virtual IOStatus Poll(std::vector<void*>& io_handles,
size_t /*min_completions*/) override {
#if defined(ROCKSDB_IOURING_PRESENT)
// io_uring_queue_init.
struct io_uring* iu = nullptr;
if (thread_local_io_urings_) {
iu = static_cast<struct io_uring*>(thread_local_io_urings_->Get());
}
// Init failed, platform doesn't support io_uring.
if (iu == nullptr) {
return IOStatus::NotSupported("Poll");
}
for (size_t i = 0; i < io_handles.size(); i++) {
// The request has been completed in earlier runs.
if ((static_cast<Posix_IOHandle*>(io_handles[i]))->is_finished) {
continue;
}
// Loop until IO for io_handles[i] is completed.
while (true) {
// io_uring_wait_cqe.
struct io_uring_cqe* cqe = nullptr;
ssize_t ret = io_uring_wait_cqe(iu, &cqe);
if (ret) {
// abort as it shouldn't be in indeterminate state and there is no
// good way currently to handle this error.
abort();
}
// Step 3: Populate the request.
assert(cqe != nullptr);
Posix_IOHandle* posix_handle =
static_cast<Posix_IOHandle*>(io_uring_cqe_get_data(cqe));
assert(posix_handle->iu == iu);
if (posix_handle->iu != iu) {
return IOStatus::IOError("");
}
// Reset cqe data to catch any stray reuse of it
static_cast<struct io_uring_cqe*>(cqe)->user_data = 0xd5d5d5d5d5d5d5d5;
FSReadRequest req;
req.scratch = posix_handle->scratch;
req.offset = posix_handle->offset;
req.len = posix_handle->len;
size_t finished_len = 0;
size_t bytes_read = 0;
bool read_again = false;
UpdateResult(cqe, "", req.len, posix_handle->iov.iov_len,
true /*async_read*/, posix_handle->use_direct_io,
posix_handle->alignment, finished_len, &req, bytes_read,
read_again);
posix_handle->is_finished = true;
io_uring_cqe_seen(iu, cqe);
posix_handle->cb(req, posix_handle->cb_arg);
(void)finished_len;
(void)bytes_read;
(void)read_again;
if (static_cast<Posix_IOHandle*>(io_handles[i]) == posix_handle) {
break;
}
}
}
return IOStatus::OK();
#else
(void)io_handles;
return IOStatus::NotSupported("Poll");
#endif
}
virtual IOStatus AbortIO(std::vector<void*>& io_handles) override {
#if defined(ROCKSDB_IOURING_PRESENT)
// io_uring_queue_init.
struct io_uring* iu = nullptr;
if (thread_local_io_urings_) {
iu = static_cast<struct io_uring*>(thread_local_io_urings_->Get());
}
// Init failed, platform doesn't support io_uring.
// If Poll is not supported then it didn't submit any request and it should
// return OK.
if (iu == nullptr) {
return IOStatus::OK();
}
for (size_t i = 0; i < io_handles.size(); i++) {
Posix_IOHandle* posix_handle =
static_cast<Posix_IOHandle*>(io_handles[i]);
if (posix_handle->is_finished == true) {
continue;
}
assert(posix_handle->iu == iu);
if (posix_handle->iu != iu) {
return IOStatus::IOError("");
}
// Prepare the cancel request.
struct io_uring_sqe* sqe;
sqe = io_uring_get_sqe(iu);
// In order to cancel the request, sqe->addr of cancel request should
// match with the read request submitted which is posix_handle->iov.
io_uring_prep_cancel(sqe, &posix_handle->iov, 0);
// Sets sqe->user_data to posix_handle.
io_uring_sqe_set_data(sqe, posix_handle);
// submit the request.
ssize_t ret = io_uring_submit(iu);
if (ret < 0) {
fprintf(stderr, "io_uring_submit error: %ld\n", long(ret));
return IOStatus::IOError("io_uring_submit() requested but returned " +
std::to_string(ret));
}
}
// After submitting the requests, wait for the requests.
for (size_t i = 0; i < io_handles.size(); i++) {
if ((static_cast<Posix_IOHandle*>(io_handles[i]))->is_finished) {
continue;
}
while (true) {
struct io_uring_cqe* cqe = nullptr;
ssize_t ret = io_uring_wait_cqe(iu, &cqe);
if (ret) {
// abort as it shouldn't be in indeterminate state and there is no
// good way currently to handle this error.
abort();
}
assert(cqe != nullptr);
// Returns cqe->user_data.
Posix_IOHandle* posix_handle =
static_cast<Posix_IOHandle*>(io_uring_cqe_get_data(cqe));
assert(posix_handle->iu == iu);
if (posix_handle->iu != iu) {
return IOStatus::IOError("");
}
posix_handle->req_count++;
// Reset cqe data to catch any stray reuse of it
static_cast<struct io_uring_cqe*>(cqe)->user_data = 0xd5d5d5d5d5d5d5d5;
io_uring_cqe_seen(iu, cqe);
// - If the request is cancelled successfully, the original request is
// completed with -ECANCELED and the cancel request is completed with
// a result of 0.
// - If the request was already running, the original may or
// may not complete in error. The cancel request will complete with
// -EALREADY for that case.
// - And finally, if the request to cancel wasn't
// found, the cancel request is completed with -ENOENT.
//
// Every handle has to wait for 2 requests completion: original one and
// the cancel request which is tracked by PosixHandle::req_count.
if (posix_handle->req_count == 2 &&
static_cast<Posix_IOHandle*>(io_handles[i]) == posix_handle) {
posix_handle->is_finished = true;
FSReadRequest req;
req.status = IOStatus::Aborted();
posix_handle->cb(req, posix_handle->cb_arg);
break;
}
}
}
return IOStatus::OK();
#else
// If Poll is not supported then it didn't submit any request and it should
// return OK.
(void)io_handles;
return IOStatus::OK();
#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_;
#ifdef OS_LINUX
static LogicalBlockSizeCache logical_block_size_cache_;
#endif
static size_t GetLogicalBlockSize(const std::string& fname, int fd);
// In non-direct IO mode, this directly returns kDefaultPageSize.
// Otherwise call GetLogicalBlockSize.
static size_t GetLogicalBlockSizeForReadIfNeeded(const EnvOptions& options,
const std::string& fname,
int fd);
static size_t GetLogicalBlockSizeForWriteIfNeeded(const EnvOptions& options,
const std::string& fname,
int fd);
};
#ifdef OS_LINUX
LogicalBlockSizeCache PosixFileSystem::logical_block_size_cache_;
#endif
size_t PosixFileSystem::GetLogicalBlockSize(const std::string& fname, int fd) {
#ifdef OS_LINUX
return logical_block_size_cache_.GetLogicalBlockSize(fname, fd);
#else
(void)fname;
return PosixHelper::GetLogicalBlockSizeOfFd(fd);
#endif
}
size_t PosixFileSystem::GetLogicalBlockSizeForReadIfNeeded(
const EnvOptions& options, const std::string& fname, int fd) {
return options.use_direct_reads
? PosixFileSystem::GetLogicalBlockSize(fname, fd)
: kDefaultPageSize;
}
size_t PosixFileSystem::GetLogicalBlockSizeForWriteIfNeeded(
const EnvOptions& options, const std::string& fname, int fd) {
return options.use_direct_writes
? PosixFileSystem::GetLogicalBlockSize(fname, fd)
: kDefaultPageSize;
}
PosixFileSystem::PosixFileSystem()
: 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_AVOID_DESTRUCTION(std::shared_ptr<FileSystem>, instance)
(std::make_shared<PosixFileSystem>());
return instance;
}
#ifndef ROCKSDB_LITE
static FactoryFunc<FileSystem> posix_filesystem_reg =
ObjectLibrary::Default()->AddFactory<FileSystem>(
ObjectLibrary::PatternEntry("posix").AddSeparator("://", false),
[](const std::string& /* uri */, std::unique_ptr<FileSystem>* f,
std::string* /* errmsg */) {
f->reset(new PosixFileSystem());
return f->get();
});
#endif
} // namespace ROCKSDB_NAMESPACE
#endif