1.\" -*- nroff -*- 2.\" 3.\" Copyright (c) 1996 Doug Rabson 4.\" 5.\" All rights reserved. 6.\" 7.\" This program is free software. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 19.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 22.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28.\" 29.\" $FreeBSD$ 30.\" 31.Dd July 24, 1996 32.Os 33.Dt VOP_FSYNC 9 34.Sh NAME 35.Nm VOP_FSYNC 36.Nd flush file system buffers for a file 37.Sh SYNOPSIS 38.In sys/param.h 39.In sys/vnode.h 40.Ft int 41.Fn VOP_FSYNC "struct vnode *vp" "struct ucred *cred" "int waitfor" "struct thread *td" 42.Sh DESCRIPTION 43This call flushes any dirty file system buffers for the file. 44It is used to implement the 45.Xr sync 2 46and 47.Xr fsync 2 48system calls. 49.Pp 50Its arguments are: 51.Bl -tag -width waitfor 52.It Fa vp 53the vnode of the file 54.It Fa cred 55the caller's credentials 56.It Fa waitfor 57whether the function should wait for I/O to complete. 58Possible values are: 59.Bl -tag -width MNT_NOWAIT 60.It Dv MNT_WAIT 61synchronously wait for I/O to complete 62.It Dv MNT_NOWAIT 63start all I/O, but do not wait for it 64.It Dv MNT_LAZY 65push data not written by file system syncer 66.El 67.It Fa td 68the calling thread 69.El 70.Pp 71The argument 72.Fa waitfor 73is either 74.Dv MNT_WAIT 75or 76.Dv MNT_NOWAIT 77and specifies whether or not the function should wait for the writes 78to finish before returning. 79.Sh LOCKS 80The file should be locked on entry. 81.Sh RETURN VALUES 82Zero is returned if the call is successful, otherwise an appropriate 83error code is returned. 84.Sh PSEUDOCODE 85.Bd -literal 86int 87vop_fsync(struct vnode *vp, struct ucred *cred, int waitfor, struct thread *td) 88{ 89 struct buf *bp; 90 struct buf *nbp; 91 struct timeval tv; 92 int s; 93 94loop: 95 s = splbio(); 96 for (bp = vp->v_dirtyblkhd.lh_first; bp; bp = nbp) { 97 nbp = bp->b_vnbufs.le_next; 98 99 /* 100 * Ignore buffers which are already being written. 101 */ 102 if (bp->b_flags & B_BUSY) 103 continue; 104 105 /* 106 * Make sure the buffer is dirty. 107 */ 108 if ((bp->b_flags & B_DELWRI) == 0) 109 panic("vop_fsync: not dirty"); 110 111 vfs_bio_awrite(bp); 112 splx(s); 113 goto loop; 114 } 115 splx(s); 116 117 if (waitfor == MNT_WAIT) { 118 s = splbio(); 119 while (vp->v_numoutput) { 120 vp->v_flag |= VBWAIT; 121 tsleep((caddr_t)&vp->v_numoutput, PRIBIO + 1, "vopfsn"); 122 } 123 splx(s); 124#ifdef DIAGNOSTIC 125 if (vp->v_dirtyblkhd.lh_first) { 126 vprint("vop_fsync: dirty", vp); 127 goto loop; 128 } 129#endif 130 } 131 132 /* 133 * Write out the on-disc version of the vnode. 134 */ 135 tv = time; 136 return VOP_UPDATE(vp, &tv, &tv, waitfor == MNT_WAIT); 137} 138.Ed 139.Sh ERRORS 140.Bl -tag -width Er 141.It Bq Er ENOSPC 142The file system is full. 143.It Bq Er EDQUOT 144Quota exceeded. 145.El 146.Sh SEE ALSO 147.Xr vnode 9 148.Sh AUTHORS 149This man page was written by 150.An Doug Rabson . 151