null.h revision 240285 
1/*-
2 * Copyright (c) 1992, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software donated to Berkeley by
6 * Jan-Simon Pendry.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 4. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 *	@(#)null.h	8.3 (Berkeley) 8/20/94
33 *
34 * $FreeBSD: head/sys/fs/nullfs/null.h 240285 2012-09-09 19:20:23Z kib $
35 */
36
37struct null_mount {
38	struct mount	*nullm_vfs;
39	struct vnode	*nullm_rootvp;	/* Reference to root null_node */
40};
41
42#ifdef _KERNEL
43/*
44 * A cache of vnode references
45 */
46struct null_node {
47	LIST_ENTRY(null_node)	null_hash;	/* Hash list */
48	struct vnode	        *null_lowervp;	/* VREFed once */
49	struct vnode		*null_vnode;	/* Back pointer */
50};
51
52#define	MOUNTTONULLMOUNT(mp) ((struct null_mount *)((mp)->mnt_data))
53#define	VTONULL(vp) ((struct null_node *)(vp)->v_data)
54#define	NULLTOV(xp) ((xp)->null_vnode)
55
56int nullfs_init(struct vfsconf *vfsp);
57int nullfs_uninit(struct vfsconf *vfsp);
58int null_nodeget(struct mount *mp, struct vnode *target, struct vnode **vpp);
59struct vnode *null_hashget(struct mount *mp, struct vnode *lowervp);
60void null_hashrem(struct null_node *xp);
61int null_bypass(struct vop_generic_args *ap);
62
63#ifdef DIAGNOSTIC
64struct vnode *null_checkvp(struct vnode *vp, char *fil, int lno);
65#define	NULLVPTOLOWERVP(vp) null_checkvp((vp), __FILE__, __LINE__)
66#else
67#define	NULLVPTOLOWERVP(vp) (VTONULL(vp)->null_lowervp)
68#endif
69
70extern struct vop_vector null_vnodeops;
71
72#ifdef MALLOC_DECLARE
73MALLOC_DECLARE(M_NULLFSNODE);
74#endif
75
76#ifdef NULLFS_DEBUG
77#define NULLFSDEBUG(format, args...) printf(format ,## args)
78#else
79#define NULLFSDEBUG(format, args...)
80#endif /* NULLFS_DEBUG */
81
82#endif /* _KERNEL */
83