1 // Copyright 2018 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
4 5 package poll
6 7 import (
8 "errors"
9 "internal/syscall/unix"
10 "syscall"
11 )
12 13 // Fsync invokes SYS_FCNTL with SYS_FULLFSYNC because
14 // on OS X, SYS_FSYNC doesn't fully flush contents to disk.
15 // See Issue #26650 as well as the man page for fsync on OS X.
16 func (fd *FD) Fsync() error {
17 if err := fd.incref(); err != nil {
18 return err
19 }
20 defer fd.decref()
21 return ignoringEINTR(func() error {
22 _, err := unix.Fcntl(fd.Sysfd, syscall.F_FULLFSYNC, 0)
23 24 // There are scenarios such as SMB mounts where fcntl will fail
25 // with ENOTSUP. In those cases fallback to fsync.
26 // See #64215
27 if err != nil && errors.Is(err, syscall.ENOTSUP) {
28 err = syscall.Fsync(fd.Sysfd)
29 }
30 return err
31 })
32 }
33