1.\" -*- nroff -*- 2.\" 3.\" Copyright (c) 1996 Doug Rabson 4.\" 5.\" All rights reserved. 6.\" 7.\" Copyright (c) 2019 The FreeBSD Foundation 8.\" 9.\" Portions of this documentation were written by BFF Storage Systems under 10.\" sponsorship from the FreeBSD Foundation. 11.\" 12.\" This program is free software. 13.\" 14.\" Redistribution and use in source and binary forms, with or without 15.\" modification, are permitted provided that the following conditions 16.\" are met: 17.\" 1. Redistributions of source code must retain the above copyright 18.\" notice, this list of conditions and the following disclaimer. 19.\" 2. Redistributions in binary form must reproduce the above copyright 20.\" notice, this list of conditions and the following disclaimer in the 21.\" documentation and/or other materials provided with the distribution. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 24.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 27.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33.\" 34.Dd March 22, 2019 35.Dt VOP_FSYNC 9 36.Os 37.Sh NAME 38.Nm VOP_FDATASYNC , 39.Nm VOP_FSYNC 40.Nd flush file system buffers for a file 41.Sh SYNOPSIS 42.In sys/param.h 43.In sys/vnode.h 44.Ft int 45.Fn VOP_FDATASYNC "struct vnode *vp" "struct thread *td" 46.Ft int 47.Fn VOP_FSYNC "struct vnode *vp" "int waitfor" "struct thread *td" 48.Sh DESCRIPTION 49.Fn VOP_FSYNC 50ensures that a file can be recovered to its current state following a crash. 51That typically requires flushing the file's dirty buffers, its inode, and 52possibly other filesystem metadata to persistent media. 53.Fn VOP_FSYNC 54is used to implement the 55.Xr sync 2 56and 57.Xr fsync 2 58system calls. 59.Pp 60Its arguments are: 61.Bl -tag -width waitfor 62.It Fa vp 63The vnode of the file. 64.It Fa waitfor 65Whether the function should wait for I/O to complete. 66Possible values are: 67.Bl -tag -width MNT_NOWAIT 68.It Dv MNT_WAIT 69Synchronously wait for I/O to complete. 70.It Dv MNT_NOWAIT 71Start all I/O, but do not wait for it. 72.It Dv MNT_LAZY 73Push data not written by file system syncer. 74.El 75.It Fa td 76The calling thread. 77.El 78.Pp 79.Fn VOP_FDATASYNC 80is similar, but it does not require that all of the file's metadata be flushed. 81It only requires that the file's data be recoverable after a crash. 82That implies that the data itself must be flushed to disk, as well as some 83metadata such as the file's size but not necessarily its attributes. 84.Fn VOP_FDATASYNC 85should always wait for I/O to complete, as if called with 86.Dv MNT_WAIT . 87.Fn VOP_FDATASYNC 88is used to implement 89.Xr fdatasync 2 . 90.Sh LOCKS 91The vnode should be exclusively locked on entry, and stays locked on return. 92.Sh RETURN VALUES 93Zero is returned if the call is successful, otherwise an appropriate 94error code is returned. 95.Sh ERRORS 96.Bl -tag -width Er 97.It Bq Er ENOSPC 98The file system is full. 99.It Bq Er EDQUOT 100Quota exceeded. 101.El 102.Sh SEE ALSO 103.Xr vnode 9 104.Sh AUTHORS 105This manual page was written by 106.An Doug Rabson . 107