1.\" Copyright (c) 1996 Doug Rabson 2.\" 3.\" All rights reserved. 4.\" 5.\" This program is free software. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 17.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 20.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26.\" 27.\" $FreeBSD: src/share/man/man9/VOP_FSYNC.9,v 1.6.2.2 2001/12/17 11:30:18 ru Exp $ 28.\" 29.Dd September 14, 2021 30.Dt VOP_FSYNC 9 31.Os 32.Sh NAME 33.Nm VOP_FDATASYNC , 34.Nm VOP_FSYNC 35.Nd flush filesystem buffers for a file 36.Sh SYNOPSIS 37.In sys/param.h 38.In sys/vnode.h 39.Ft int 40.Fn VOP_FDATASYNC "struct vnode *vp" "int waitfor" "int flags" 41.Ft int 42.Fn VOP_FSYNC "struct vnode *vp" "int waitfor" "int flags" 43.Sh DESCRIPTION 44This call flushes any dirty filesystem buffers for the file. 45It is used to implement the 46.Xr sync 2 47and 48.Xr fsync 2 49system calls. 50.Pp 51Its arguments are: 52.Bl -tag -width waitfor 53.It Ar vp 54the vnode of the file. 55.It Ar waitfor 56whether the function should do data, meta-data updates or be full-synchronous. 57.It Ar flags 58are additional flags to be passed to the filesystem specific 59.Xr fsync 2 60function. 61.El 62.Pp 63The argument 64.Fa waitfor 65can use the following flags: 66.Bl -tag -width ".Dv MNT_NOWAIT" 67.It Dv MNT_NOWAIT 68is for an asynchronous data pass and a meta-data pass as well. 69.It Dv MNT_LAZY 70means a limited amount of data from dirty buffers and a full meta-data synchronization pass. 71.It Dv MNT_WAIT 72will make 73.Xr syncer 4 74try to do a full synchronization pass. 75That is, a meta-data pass and multiple data passes. 76.El 77.Pp 78The argument 79.Fa flags 80is to specify additional flags passed to the filesystem specific 81.Xr fsync 2 82call. 83The only supported flag at the moment is 84.Dv VOP_FSYNC_SYSCALL 85which indicates the file synchronization was requested from userland. 86.Pp 87.Fn VOP_FDATASYNC 88is similar, but it does not require that all of the file's metadata be flushed. 89It only requires that the file's data be recoverable after a crash. 90That implies that the data itself must be flushed to disk, as well as some 91metadata such as the file's size but not necessarily its attributes. 92.Fn VOP_FDATASYNC 93should always wait for I/O to complete, as if called with 94.Dv MNT_WAIT . 95.Fn VOP_FDATASYNC 96is used to implement 97.Xr fdatasync 2 . 98.Sh RETURN VALUES 99Zero is returned if the call is successful, otherwise an appropriate 100error code is returned. 101.Sh ERRORS 102.Bl -tag -width Er 103.It Bq Er ENOSPC 104The filesystem is full. 105.It Bq Er EDQUOT 106Quota exceeded. 107.El 108.Sh SEE ALSO 109.Xr syncer 4 , 110.Xr vnode 9 111.Sh AUTHORS 112This man page was written by 113.An Doug Rabson . 114