1*86d7f5d3SJohn Marino.\" Copyright (c) 1996 Doug Rabson 2*86d7f5d3SJohn Marino.\" 3*86d7f5d3SJohn Marino.\" All rights reserved. 4*86d7f5d3SJohn Marino.\" 5*86d7f5d3SJohn Marino.\" This program is free software. 6*86d7f5d3SJohn Marino.\" 7*86d7f5d3SJohn Marino.\" Redistribution and use in source and binary forms, with or without 8*86d7f5d3SJohn Marino.\" modification, are permitted provided that the following conditions 9*86d7f5d3SJohn Marino.\" are met: 10*86d7f5d3SJohn Marino.\" 1. Redistributions of source code must retain the above copyright 11*86d7f5d3SJohn Marino.\" notice, this list of conditions and the following disclaimer. 12*86d7f5d3SJohn Marino.\" 2. Redistributions in binary form must reproduce the above copyright 13*86d7f5d3SJohn Marino.\" notice, this list of conditions and the following disclaimer in the 14*86d7f5d3SJohn Marino.\" documentation and/or other materials provided with the distribution. 15*86d7f5d3SJohn Marino.\" 16*86d7f5d3SJohn Marino.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 17*86d7f5d3SJohn Marino.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18*86d7f5d3SJohn Marino.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19*86d7f5d3SJohn Marino.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 20*86d7f5d3SJohn Marino.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21*86d7f5d3SJohn Marino.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22*86d7f5d3SJohn Marino.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23*86d7f5d3SJohn Marino.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24*86d7f5d3SJohn Marino.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25*86d7f5d3SJohn Marino.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26*86d7f5d3SJohn Marino.\" 27*86d7f5d3SJohn Marino.\" $FreeBSD: src/share/man/man9/vref.9,v 1.6.2.2 2001/12/17 11:30:19 ru Exp $ 28*86d7f5d3SJohn Marino.\" 29*86d7f5d3SJohn Marino.Dd May 5, 2007 30*86d7f5d3SJohn Marino.Dt VREF 9 31*86d7f5d3SJohn Marino.Os 32*86d7f5d3SJohn Marino.Sh NAME 33*86d7f5d3SJohn Marino.Nm vref 34*86d7f5d3SJohn Marino.Nd Increment the primary reference count for an active vnode 35*86d7f5d3SJohn Marino.Sh SYNOPSIS 36*86d7f5d3SJohn Marino.In sys/param.h 37*86d7f5d3SJohn Marino.In sys/vnode.h 38*86d7f5d3SJohn Marino.Ft void 39*86d7f5d3SJohn Marino.Fn vref "struct vnode *vp" 40*86d7f5d3SJohn Marino.Sh DESCRIPTION 41*86d7f5d3SJohn MarinoThe primary reference count for an active vnode is incremented. 42*86d7f5d3SJohn MarinoThe vnode must already have active references to it, usually acquired 43*86d7f5d3SJohn Marinoprior to the vnode pointer being passed to the code making this call 44*86d7f5d3SJohn Marinoor when vnode pointers are obtained from structures, such as file pointers, 45*86d7f5d3SJohn Marinowhich hold an active reference to the vnode. 46*86d7f5d3SJohn MarinoAny attempt to use 47*86d7f5d3SJohn Marino.Nm 48*86d7f5d3SJohn Marinoon an inactive vnode will result in a panic. 49*86d7f5d3SJohn Marino.Bl -tag -width ".Fa vp" 50*86d7f5d3SJohn Marino.It Fa vp 51*86d7f5d3SJohn MarinoThe vnode being referenced. 52*86d7f5d3SJohn Marino.El 53*86d7f5d3SJohn Marino.Pp 54*86d7f5d3SJohn MarinoEach vnode maintains a Primary and Auxiliary reference count. 55*86d7f5d3SJohn MarinoThe primary reference count prevents the vnode from being deactivated 56*86d7f5d3SJohn Marinowhile the auxiliary reference count keeps track of auxiliary structures, 57*86d7f5d3SJohn Marinosuch as namecache and VM object structures, which are typically kept 58*86d7f5d3SJohn Marinoassociated with the vnode for caching purposes even after the vnode 59*86d7f5d3SJohn Marinohas been deactivated. 60*86d7f5d3SJohn Marino.Pp 61*86d7f5d3SJohn MarinoA procedure will often acquire its own primary reference to a vnode 62*86d7f5d3SJohn Marinoto prevent the vnode from getting ripped out from under it during 63*86d7f5d3SJohn Marinoan operation due to the destruction of the parent data structure. 64*86d7f5d3SJohn MarinoFor example, one thread may be blocked on a vnode operation related 65*86d7f5d3SJohn Marinoto a file descriptor that another thread then closes. 66*86d7f5d3SJohn Marino.Sh SEE ALSO 67*86d7f5d3SJohn Marino.Xr vdrop 9 , 68*86d7f5d3SJohn Marino.Xr vget 9 , 69*86d7f5d3SJohn Marino.Xr vhold 9 , 70*86d7f5d3SJohn Marino.Xr vnode 9 , 71*86d7f5d3SJohn Marino.Xr vn_lock 9 , 72*86d7f5d3SJohn Marino.Xr vn_unlock 9 , 73*86d7f5d3SJohn Marino.Xr vput 9 , 74*86d7f5d3SJohn Marino.Xr vrele 9 75*86d7f5d3SJohn Marino.Sh AUTHORS 76*86d7f5d3SJohn MarinoThis manual page was written by 77*86d7f5d3SJohn Marino.An Doug Rabson . 78