2001-12-02 02:13:35 +00:00
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.\"
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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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.\" 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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.\" 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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.\"
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.\" $FreeBSD$
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.\"
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2007-04-01 09:48:59 +00:00
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.Dd April 1, 2007
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2001-12-02 02:13:35 +00:00
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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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2008-02-26 20:25:01 +00:00
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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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2005-07-22 00:28:22 +00:00
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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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2005-07-22 00:28:22 +00:00
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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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2008-02-26 20:25:01 +00:00
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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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2008-02-26 20:25:01 +00:00
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.Xr vnode 9
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2001-12-02 02:13:35 +00:00
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.Sh AUTHORS
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2005-06-28 20:15:19 +00:00
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This manual page was written by
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2001-12-02 02:13:35 +00:00
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.An Chad David Aq davidc@acns.ab.ca .
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