109 lines
3.4 KiB
Groff
109 lines
3.4 KiB
Groff
.\" -*- nroff -*-
|
|
.\"
|
|
.\" Copyright (c) 1996 Doug Rabson
|
|
.\"
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" Copyright (c) 2019 The FreeBSD Foundation
|
|
.\"
|
|
.\" Portions of this documentation were written by BFF Storage Systems under
|
|
.\" sponsorship from the FreeBSD Foundation.
|
|
.\"
|
|
.\" This program is free software.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
|
|
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
|
|
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
|
|
.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
|
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|
.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|
.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
|
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd March 22, 2019
|
|
.Dt VOP_FSYNC 9
|
|
.Os
|
|
.Sh NAME
|
|
.Nm VOP_FDATASYNC ,
|
|
.Nm VOP_FSYNC
|
|
.Nd flush file system buffers for a file
|
|
.Sh SYNOPSIS
|
|
.In sys/param.h
|
|
.In sys/vnode.h
|
|
.Ft int
|
|
.Fn VOP_FDATASYNC "struct vnode *vp" "struct thread *td"
|
|
.Ft int
|
|
.Fn VOP_FSYNC "struct vnode *vp" "int waitfor" "struct thread *td"
|
|
.Sh DESCRIPTION
|
|
.Fn VOP_FSYNC
|
|
ensures that a file can be recovered to its current state following a crash.
|
|
That typically requires flushing the file's dirty buffers, its inode, and
|
|
possibly other filesystem metadata to persistent media.
|
|
.Fn VOP_FSYNC
|
|
is used to implement the
|
|
.Xr sync 2
|
|
and
|
|
.Xr fsync 2
|
|
system calls.
|
|
.Pp
|
|
Its arguments are:
|
|
.Bl -tag -width waitfor
|
|
.It Fa vp
|
|
The vnode of the file.
|
|
.It Fa waitfor
|
|
Whether the function should wait for I/O to complete.
|
|
Possible values are:
|
|
.Bl -tag -width MNT_NOWAIT
|
|
.It Dv MNT_WAIT
|
|
Synchronously wait for I/O to complete.
|
|
.It Dv MNT_NOWAIT
|
|
Start all I/O, but do not wait for it.
|
|
.It Dv MNT_LAZY
|
|
Push data not written by file system syncer.
|
|
.El
|
|
.It Fa td
|
|
The calling thread.
|
|
.El
|
|
.Pp
|
|
.Fn VOP_FDATASYNC
|
|
is similar, but it does not require that all of the file's metadata be flushed.
|
|
It only requires that the file's data be recoverable after a crash.
|
|
That implies that the data itself must be flushed to disk, as well as some
|
|
metadata such as the file's size but not necessarily its attributes.
|
|
.Fn VOP_FDATASYNC
|
|
should always wait for I/O to complete, as if called with
|
|
.Dv MNT_WAIT .
|
|
.Fn VOP_FDATASYNC
|
|
is used to implement
|
|
.Xr fdatasync 2 .
|
|
.Sh LOCKS
|
|
The vnode should be exclusively locked on entry, and stays locked on return.
|
|
.Sh RETURN VALUES
|
|
Zero is returned if the call is successful, otherwise an appropriate
|
|
error code is returned.
|
|
.Sh ERRORS
|
|
.Bl -tag -width Er
|
|
.It Bq Er ENOSPC
|
|
The file system is full.
|
|
.It Bq Er EDQUOT
|
|
Quota exceeded.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr vnode 9
|
|
.Sh AUTHORS
|
|
This manual page was written by
|
|
.An Doug Rabson .
|