1.\" 2.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice(s), this list of conditions and the following disclaimer as 9.\" the first lines of this file unmodified other than the possible 10.\" addition of one or more copyright notices. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice(s), this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY 16.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 17.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 18.\" DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY 19.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 20.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 21.\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 22.\" CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH 25.\" DAMAGE. 26.\" 27.Dd April 1, 2007 28.Dt VHOLD 9 29.Os 30.Sh NAME 31.Nm vhold , vdrop , vdropl 32.Nd "acquire/release a hold on a vnode" 33.Sh SYNOPSIS 34.In sys/param.h 35.In sys/vnode.h 36.Ft void 37.Fn vhold "struct vnode *vp" 38.Ft void 39.Fn vholdl "struct vnode *vp" 40.Ft void 41.Fn vdrop "struct vnode *vp" 42.Ft void 43.Fn vdropl "struct vnode *vp" 44.Sh DESCRIPTION 45The 46.Fn vhold 47and 48.Fn vholdl 49functions increment the 50.Va v_holdcnt 51of the given vnode. 52If the vnode has already been added to the free list and is still referenced, 53it will be removed. 54.Pp 55The 56.Fn vdrop 57and 58.Fn vdropl 59functions decrement the 60.Va v_holdcnt 61of the vnode. 62If the holdcount is less than or equal to zero prior to calling 63.Fn vdrop 64or 65.Fn vdropl , 66the system will panic. 67If the vnode is no longer referenced, it will be freed. 68.Pp 69.Fn vhold 70and 71.Fn vdrop 72lock the vnode interlock while 73.Fn vholdl 74and 75.Fn vdropl 76expect the interlock to already be held. 77.Sh SEE ALSO 78.Xr vnode 9 79.Sh AUTHORS 80This manual page was written by 81.An Chad David Aq Mt davidc@acns.ab.ca . 82