xref: /freebsd/share/man/man9/vref.9 (revision 7f3dea244c40159a41ab22da77a434d7c5b5e85a)
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3.\" Copyright (c) 1996 Doug Rabson
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29.\" $FreeBSD$
30.\"
31.Dd July 24, 1996
32.Os
33.Dt VREF 9
34.Sh NAME
35.Nm vref
36.Nd increment the use count for a vnode
37.Sh SYNOPSIS
38.Fd #include <sys/param.h>
39.Fd #include <sys/vnode.h>
40.Ft void
41.Fn vref "struct vnode *vp"
42.Sh DESCRIPTION
43Increment the
44.Dv v_usecount
45field of a vnode.
46.Bl -tag -width vp
47.It Ar vp
48the vnode to increment
49.El
50.Pp
51Each vnode maintains a reference count of how many parts of the system
52are using the vnode.  This allows the system to detect when a vnode is
53no longer being used and can be safely recycled for a different file.
54.Pp
55Any code in the system which is using a vnode (e.g. during the
56operation of some algorithm or to store in a data structure) should
57call
58.Xr vref 9 .
59.Sh SEE ALSO
60.Xr vget 9 ,
61.Xr vnode 9 ,
62.Xr vput 9 ,
63.Xr vrele 9
64.Sh AUTHORS
65This man page was written by
66.An Doug Rabson .
67