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.\" $DragonFly: src/share/man/man9/VOP_FSYNC.9,v 1.4 2004/06/01 11:36:53 hmp Exp $ 29.\" 30.Dd July 24, 1996 31.Os 32.Dt VOP_FSYNC 9 33.Sh NAME 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_FSYNC "struct vnode *vp" "struct ucred *cred" "int waitfor" "struct proc *p" 41.Sh DESCRIPTION 42This call flushes any dirty filesystem buffers for the file. 43It is used to implement the 44.Xr sync 2 45and 46.Xr fsync 2 47system calls. 48.Pp 49Its arguments are: 50.Bl -tag -width waitfor 51.It Ar vp 52the vnode of the file 53.It Ar cred 54the caller's credentials 55.It Ar waitfor 56whether the function should wait for I/O to complete 57.It Ar p 58the calling process 59.El 60.Pp 61The argument 62.Fa waitfor 63is either 64.Dv MNT_WAIT 65or 66.Dv MNT_NOWAIT 67and specifies whether or not the function should wait for the writes 68to finish before returning. 69.Sh LOCKS 70The file should be locked on entry. 71.Sh RETURN VALUES 72Zero is returned if the call is successful, otherwise an appropriate 73error code is returned. 74.Sh PSEUDOCODE 75.Bd -literal 76int 77vop_fsync(struct vnode *vp, struct ucred *cred, int waitfor, struct proc *p) 78{ 79 struct buf *bp; 80 struct buf *nbp; 81 struct timeval tv; 82 int s; 83 84loop: 85 s = splbio(); 86 for (bp = vp->v_dirtyblkhd.lh_first; bp; bp = nbp) { 87 nbp = bp->b_vnbufs.le_next; 88 89 /* 90 * Ignore buffers which are already being written. 91 */ 92 if (bp->b_flags & B_BUSY) 93 continue; 94 95 /* 96 * Make sure the buffer is dirty. 97 */ 98 if ((bp->b_flags & B_DELWRI) == 0) 99 panic("vop_fsync: not dirty"); 100 101 vfs_bio_awrite(bp); 102 splx(s); 103 goto loop; 104 } 105 splx(s); 106 107 if (waitfor == MNT_WAIT) { 108 s = splbio(); 109 while (vp->v_numoutput) { 110 vp->v_flag |= VBWAIT; 111 tsleep((caddr_t)&vp->v_numoutput, 0, "vopfsn"); 112 } 113 splx(s); 114#ifdef DIAGNOSTIC 115 if (vp->v_dirtyblkhd.lh_first) { 116 vprint("vop_fsync: dirty", vp); 117 goto loop; 118 } 119#endif 120 } 121 122 /* 123 * Write out the on-disc version of the vnode. 124 */ 125 tv = time; 126 return VOP_UPDATE(vp, &tv, &tv, waitfor == MNT_WAIT); 127} 128.Ed 129.Sh ERRORS 130.Bl -tag -width Er 131.It Bq Er ENOSPC 132The filesystem is full. 133.It Bq Er EDQUOT 134Quota exceeded. 135.El 136.Sh SEE ALSO 137.Xr vnode 9 138.Sh AUTHORS 139This man page was written by 140.An Doug Rabson . 141