func (fd *FD) Fchmod(mode uint32) error {
	if err := fd.incref(); err != nil {
		return err
	}
	defer fd.decref()
	return ignoringEINTR(func() error {
		return syscall.Fchmod(fd.Sysfd, mode)
	})
}

// Fstat wraps syscall.Fstat
func (fd *FD) Fstat(s *syscall.Stat_t) error {
	if err := fd.incref(); err != nil {
		return err
	}
	defer fd.decref()
	return ignoringEINTR(func() error {

	// At this point we should cancel any pending I/O.
	// How do we do that on Plan 9?

	err := file.decref()

	// no need for a finalizer anymore
	runtime.SetFinalizer(file, nil)
	return err
}

// destroy actually closes the descriptor. This is called when
// there are no remaining references, by the decref, readUnlock,
// and writeUnlock methods.
func (file *file) destroy() error {
	var err error

func (fd *FD) WSAIoctl(iocc uint32, inbuf *byte, cbif uint32, outbuf *byte, cbob uint32, cbbr *uint32, overlapped *syscall.Overlapped, completionRoutine uintptr) error {
	if err := fd.incref(); err != nil {
		return err
	}
	defer fd.decref()
	return syscall.WSAIoctl(fd.Sysfd, iocc, inbuf, cbif, outbuf, cbob, cbbr, overlapped, completionRoutine)

package poll

import "syscall"

// SetsockoptByte wraps the setsockopt network call with a byte argument.
func (fd *FD) SetsockoptByte(level, name int, arg byte) error {
	if err := fd.incref(); err != nil {
		return err
	}
	defer fd.decref()
	return syscall.SetsockoptByte(fd.Sysfd, level, name, arg)

// on OS X, SYS_FSYNC doesn't fully flush contents to disk.
// See Issue #26650 as well as the man page for fsync on OS X.
func (fd *FD) Fsync() error {
	if err := fd.incref(); err != nil {
		return err
	}
	defer fd.decref()
	return ignoringEINTR(func() error {
		_, err := unix.Fcntl(fd.Sysfd, syscall.F_FULLFSYNC, 0)

		// There are scenarios such as SMB mounts where fcntl will fail

func (fd *FD) Fchdir() error {
	if err := fd.incref(); err != nil {
		return err
	}
	defer fd.decref()
	return syscall.Chdir(fd.Path)
}

// ReadDir wraps syscall.ReadDir.
// We treat this like an ordinary system call rather than a call
// that tries to fill the buffer.
func (fd *FD) ReadDir(buf []byte, cookie syscall.Dircookie) (int, error) {
	if err := fd.incref(); err != nil {
		return 0, err
	}

import "syscall"

// SetsockoptIPMreqn wraps the setsockopt network call with an IPMreqn argument.
func (fd *FD) SetsockoptIPMreqn(level, name int, mreq *syscall.IPMreqn) error {
	if err := fd.incref(); err != nil {
		return err
	}
	defer fd.decref()
	return syscall.SetsockoptIPMreqn(fd.Sysfd, level, name, mreq)

package poll

import "syscall"

// Fsync wraps syscall.Fsync.
func (fd *FD) Fsync() error {
	if err := fd.incref(); err != nil {
		return err
	}
	defer fd.decref()
	return ignoringEINTR(func() error {
		return syscall.Fsync(fd.Sysfd)
	})

	d := t.UnixNano()
	if t.IsZero() {
		d = 0
	}
	if err := fd.incref(); err != nil {
		return err
	}
	switch mode {
	case 'r':
		syscall.SetReadDeadline(fd.Sysfd, d)
	case 'w':
		syscall.SetWriteDeadline(fd.Sysfd, d)
	case 'r' + 'w':
		syscall.SetReadDeadline(fd.Sysfd, d)
		syscall.SetWriteDeadline(fd.Sysfd, d)
	}
	fd.decref()
	return nil
}

	for i := 0; i < 2; i++ {
		buf := make([]byte, bitSize16+size)

		var n int
		switch a := arg.(type) {
		case *File:
			name = a.name
			if err := a.incref("fstat"); err != nil {
				return nil, err
			}
			n, err = syscall.Fstat(a.fd, buf)
			a.decref()
		case string:
			name = a
			n, err = syscall.Stat(a, buf)
		default:
			panic("phase error in dirstat")
		}

		if n < bitSize16 {