Bug 23745

When trying to understand a part of the kernel I found a number of undocumented
functions. I documented vcount based on the comments in the code...I think I've
got it right but haven't manged to get any reviewers as yet.

Fix: 

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.\" Copyright (c) 2000 Andrew Stevenson
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.\"	Andrew <andrew@ugh.net.au>
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.\" $Id$
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.Dd November 4th, 2000
.Os
.Dt VCOUNT 9
.Sh NAME
.Nm vcount ,
.Nm count_dev
.Nd get total number of references to a device.
.Sh SYNOPSIS
.Fd #include <sys/types.h>
.Fd #include <sys/conf.h>
.Fd #include <sys/vnode.h>
.Ft int
.Fn vcount "struct vnode *vp"
.Ft int
.Fn count_dev "dev_t dev"

.Sh DESCRIPTION

.Fn vcount
is used to get the number of users of (code with references to)  a
particular device. It allows for the fact that multiple vnodes may
reference the same device.

.Fn count_dev
does the same thing as vcount but takes a dev_t rather than a vnode
pointer as an argument.

.Sh RETURN VALUES
.Fn vcount
and
.Fn count_dev
both return the number of users of the device.

.Sh SEE ALSO
.Xr VFS 9 ,
.Xr vnode 9 ,
.Pa src/sys/kern/vfs_subr.c
.Sh AUTHORS
This man page was written by
.An Andrew Stevenson .