72 lines
2.4 KiB
Groff
72 lines
2.4 KiB
Groff
.\" -*- nroff -*-
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.\"
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.\" Copyright (c) 1996 Doug Rabson
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.\"
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.\" All rights reserved.
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.\"
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.\" This program is free software.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
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.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd July 24, 1996
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.Os
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.Dt VGET 9
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.Sh NAME
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.Nm vget
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.Nd get a vnode from the free list
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.Sh SYNOPSIS
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.In sys/param.h
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.In sys/vnode.h
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.Ft int
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.Fn vget "struct vnode *vp" "int lockflag" "struct thread *td"
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.Sh DESCRIPTION
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Get a vnode from the free list and increment its reference count.
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.Bl -tag -width lockflag
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.It Fa vp
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the vnode to remove from the free list
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.It Fa lockflag
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if non-zero, the vnode will also be locked
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.El
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.Pp
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When not in use, vnodes are kept on a free list.
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The vnodes still
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reference valid files but may be reused to refer to a new file at any
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time.
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Often, these vnodes are also held in caches in the system, such
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as the name cache.
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.Pp
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When a vnode which is on the free list is used again, for instance if
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the vnode was found in the name cache as a result of a call to
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.Xr VOP_LOOKUP 9
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then the new user must call
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.Fn vget
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to increment the reference count and remove it from the free list.
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.Sh SEE ALSO
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.Xr vnode 9 ,
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.Xr vput 9 ,
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.Xr vref 9 ,
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.Xr vrele 9
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.Sh AUTHORS
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This man page was written by
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.An Doug Rabson .
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