Golang syscall.Fsync函數代碼示例

func TestFSync(t *testing.T) {
	tc := NewTestCase(t)
	defer tc.Cleanup()

	contents := []byte{1, 2, 3}
	if err := ioutil.WriteFile(tc.origFile, []byte(contents), 0700); err != nil {
		t.Fatalf("WriteFile failed: %v", err)
	}

	f, err := os.OpenFile(tc.mountFile, os.O_WRONLY, 0)
	if err != nil {
		t.Fatalf("OpenFile(%q): %v", tc.mountFile, err)
	}
	defer f.Close()

	if _, err := f.WriteString("hello there"); err != nil {
		t.Fatalf("WriteString failed: %v", err)
	}

	// How to really test fsync ?
	err = syscall.Fsync(int(f.Fd()))
	if err != nil {
		t.Errorf("fsync returned: %v", err)
	}
}

func TestCreate(t *testing.T) {
	t.Parallel()
	f := &create1{}
	mnt, err := fstestutil.MountedT(t, fstestutil.SimpleFS{f})
	if err != nil {
		t.Fatal(err)
	}
	defer mnt.Close()

	// uniform umask needed to make os.Create's 0666 into something
	// reproducible
	defer syscall.Umask(syscall.Umask(0022))
	ff, err := os.Create(mnt.Dir + "/foo")
	if err != nil {
		t.Fatalf("create1 WriteFile: %v", err)
	}
	defer ff.Close()

	err = syscall.Fsync(int(ff.Fd()))
	if err != nil {
		t.Fatalf("Fsync = %v", err)
	}

	if f.f.RecordedFsync() == (fuse.FsyncRequest{}) {
		t.Errorf("never received expected fsync call")
	}

	ff.Close()
}

func (w *write) test(path string, t *testing.T) {
	log.Printf("pre-write Create")
	f, err := os.Create(path)
	if err != nil {
		t.Fatalf("Create: %v", err)
	}
	log.Printf("pre-write Write")
	n, err := f.Write([]byte(hi))
	if err != nil {
		t.Fatalf("Write: %v", err)
	}
	if n != len(hi) {
		t.Fatalf("short write; n=%d; hi=%d", n, len(hi))
	}

	err = syscall.Fsync(int(f.Fd()))
	if err != nil {
		t.Fatalf("Fsync = %v", err)
	}
	if !<-w.seen.fsync {
		t.Errorf("never received expected fsync call")
	}

	log.Printf("pre-write Close")
	err = f.Close()
	if err != nil {
		t.Fatalf("Close: %v", err)
	}
	log.Printf("post-write Close")
	if got := string(gather(w.seen.data)); got != hi {
		t.Errorf("writeAll = %q, want %q", got, hi)
	}
}

func main() {
	flag.Usage = func() {
		fmt.Fprintf(os.Stderr, "%s", Help)
		os.Exit(1)
	}
	flag.Parse()

	dir, err := os.Getwd()
	if err != nil {
		fatal.Fatalln(err)
	}

	// "To flush all open files on a volume, call FlushFileBuffers with a handle to the volume.
	// The caller must have administrative privileges. For more information, see Running with Special Privileges."
	// https://msdn.microsoft.com/en-us/library/windows/desktop/aa364439(v=vs.85).aspx
	fp := filepath.VolumeName(dir)
	file, err := os.Open(fp)
	if err != nil {
		fatal.Fatalln(err)
	}

	err = syscall.Fsync(syscall.Handle(file.Fd()))
	if err != nil {
		fatal.Fatalln(err)
	}
}

func (f *file) Fsync(flags int) (code fuse.Status) {
	f.fdLock.Lock()
	r := fuse.ToStatus(syscall.Fsync(int(f.fd.Fd())))
	f.fdLock.Unlock()

	return r
}

func (f *loopbackFile) Fsync(flags int) (code fuse.Status) {
	f.lock.Lock()
	r := fuse.ToStatus(syscall.Fsync(int(f.File.Fd())))
	f.lock.Unlock()

	return r
}

func main() {
	var rval int = sysexits.OK

	args := os.Args
	if len(args) < 2 {
		usage()
	}

	for _, f := range args[1:] {
		if fd, err := syscall.Open(f, syscall.O_RDONLY, 0777); err != nil {
			log.Printf("open %s: %v\n", f, err)
			if rval == sysexits.OK {
				rval = sysexits.NOINPUT
			}
			continue
		} else {
			if errf := syscall.Fsync(fd); errf != nil {
				log.Printf("fsync %s:%v\n", f, errf)
				if rval == sysexits.OK {
					rval = sysexits.OSERR
				}
			}
			syscall.Close(fd)
		}
	}
	os.Exit(rval)
}

// Save the snapshot to a file
func (ss *Snapshot) save() error {
	// Write machine state to temporary buffer.

	// open file
	file, err := os.OpenFile(ss.Path, os.O_CREATE|os.O_WRONLY, 0600)

	if err != nil {
		return err
	}

	defer file.Close()

	b, err := json.Marshal(ss)

	// Generate checksum.
	checksum := crc32.ChecksumIEEE(b)

	// Write snapshot with checksum.
	if _, err = fmt.Fprintf(file, "%08x\n", checksum); err != nil {
		return err
	}

	if _, err = file.Write(b); err != nil {
		return err
	}

	// force the change writting to disk
	syscall.Fsync(int(file.Fd()))
	return err
}

func ObjDeleteHandler(writer http.ResponseWriter, request *http.Request, vars map[string]string, config ServerConfig) {
	hash_dir := ObjHashDir(vars, config)

	if os.MkdirAll(hash_dir, 0770) != nil {
		ErrorResponse(writer, 500)
		return
	}
	file_name := fmt.Sprintf("%s/%s.ts", hash_dir, request.Header.Get("X-Timestamp"))
	data_file := PrimaryFile(hash_dir)
	temp_file, err := ioutil.TempFile(ObjTempDir(vars, config), "PUT")
	if err != nil {
		ErrorResponse(writer, 500)
		return
	}
	defer temp_file.Close()
	metadata := make(map[string]interface{})
	metadata["X-Timestamp"] = request.Header.Get("X-Timestamp")
	metadata["name"] = fmt.Sprintf("/%s/%s/%s", vars["account"], vars["container"], vars["obj"])
	WriteMetadata(int(temp_file.Fd()), metadata)

	syscall.Fsync(int(temp_file.Fd()))
	syscall.Rename(temp_file.Name(), file_name)
	UpdateContainer("DELETE", metadata, request, vars)
	go CleanupHashDir(hash_dir)
	go InvalidateHash(hash_dir)
	if !strings.HasSuffix(data_file, ".data") {
		ErrorResponse(writer, 404)
	} else {
		ErrorResponse(writer, 204)
	}
}

func (f *AzukiFile) Fsync(flags int) (code fuse.Status) {
	f.lock.Lock()
	r := fuse.ToStatus(syscall.Fsync(int(f.File.Fd())))
	f.lock.Unlock()
	go event.Notify(event.Fsync, f.File.Name())
	return r
}

// Save the snapshot to a file
func (ss *Snapshot) Save() error {
	// Write machine state to temporary buffer.
	var b bytes.Buffer

	if _, err := fmt.Fprintf(&b, "%v", 2); err != nil {
		return err
	}

	// Generate checksum.
	checksum := crc32.ChecksumIEEE(b.Bytes())

	// open file
	file, err := os.OpenFile(ss.path, os.O_CREATE|os.O_WRONLY, 0600)

	if err != nil {
		return err
	}

	defer file.Close()

	// Write snapshot with checksum.
	if _, err = fmt.Fprintf(file, "%08x\n%v\n%v\n", checksum, ss.lastIndex,
		ss.lastTerm); err != nil {
		return err
	}

	if _, err = file.Write(ss.state); err != nil {
		return err
	}

	// force the change writting to disk
	syscall.Fsync(int(file.Fd()))
	return err
}

// Sync commits the current contents of the file to stable storage.
// Typically, this means flushing the file system's in-memory copy
// of recently written data to disk.
func (f *File) Sync() error {
	if err := f.checkValid("sync"); err != nil {
		return err
	}
	if e := syscall.Fsync(f.fd); e != nil {
		return &PathError{"sync", f.name, e}
	}
	return nil
}

// Sync commits the current contents of the file to stable storage.
// Typically, this means flushing the file system's in-memory copy
// of recently written data to disk.
func (f *File) Sync() error {
	if f == nil {
		return ErrInvalid
	}
	if e := syscall.Fsync(f.fd); e != nil {
		return NewSyscallError("fsync", e)
	}
	return nil
}

// Sync commits the current contents of the file to stable storage.
// Typically, this means flushing the file system's in-memory copy
// of recently written data to disk.
func (file *File) Sync() (err Error) {
	if file == nil {
		return EINVAL
	}
	if e := syscall.Fsync(file.fd); e != 0 {
		return NewSyscallError("fsync", e)
	}
	return nil
}

// Sync commits the current contents of the file to stable storage.
// Typically, this means flushing the file system's in-memory copy
// of recently written data to disk.
func (f *File) Sync() (err error) {
	if f == nil {
		return syscall.EINVAL
	}
	if e := syscall.Fsync(f.fd); e != nil {
		return NewSyscallError("fsync", e)
	}
	return nil
}