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84 lines
2.5 KiB
Groff
84 lines
2.5 KiB
Groff
.\"
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.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. All rights reserved.
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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(s), this list of conditions and the following disclaimer as
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.\" the first lines of this file unmodified other than the possible
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.\" addition of one or more copyright notices.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice(s), 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 COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
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.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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.\" DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY
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.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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.\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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.\" CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
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.\" DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd April 1, 2007
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.Dt VHOLD 9
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.Os
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.Sh NAME
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.Nm vhold , vdrop , vdropl
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.Nd "acquire/release a hold on a vnode"
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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 void
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.Fn vhold "struct vnode *vp"
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.Ft void
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.Fn vholdl "struct vnode *vp"
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.Ft void
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.Fn vdrop "struct vnode *vp"
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.Ft void
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.Fn vdropl "struct vnode *vp"
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.Sh DESCRIPTION
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The
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.Fn vhold
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and
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.Fn vholdl
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functions increment the
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.Va v_holdcnt
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of the given vnode.
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If the vnode has already been added to the free list and is still referenced,
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it will be removed.
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.Pp
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The
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.Fn vdrop
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and
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.Fn vdropl
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functions decrement the
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.Va v_holdcnt
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of the vnode.
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If the holdcount is less than or equal to zero prior to calling
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.Fn vdrop
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or
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.Fn vdropl ,
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the system will panic.
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If the vnode is no longer referenced, it will be freed.
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.Pp
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.Fn vhold
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and
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.Fn vdrop
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lock the vnode interlock while
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.Fn vholdl
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and
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.Fn vdropl
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expect the interlock to already be held.
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.Sh SEE ALSO
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.Xr vnode 9
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.Sh AUTHORS
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This manual page was written by
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.An Chad David Aq davidc@acns.ab.ca .
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