xref: /freebsd/sys/fs/nullfs/null.h (revision e4e9813eb92cd7c4d4b819a8fbed5cbd3d92f5d8)
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  * $FreeBSD$
35  */
36 
37 struct 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  */
46 struct 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 
56 int nullfs_init(struct vfsconf *vfsp);
57 int nullfs_uninit(struct vfsconf *vfsp);
58 int null_nodeget(struct mount *mp, struct vnode *target, struct vnode **vpp);
59 void null_hashrem(struct null_node *xp);
60 int null_bypass(struct vop_generic_args *ap);
61 
62 #ifdef DIAGNOSTIC
63 struct vnode *null_checkvp(struct vnode *vp, char *fil, int lno);
64 #define	NULLVPTOLOWERVP(vp) null_checkvp((vp), __FILE__, __LINE__)
65 #else
66 #define	NULLVPTOLOWERVP(vp) (VTONULL(vp)->null_lowervp)
67 #endif
68 
69 extern struct vop_vector null_vnodeops;
70 
71 #ifdef MALLOC_DECLARE
72 MALLOC_DECLARE(M_NULLFSNODE);
73 #endif
74 
75 #ifdef NULLFS_DEBUG
76 #define NULLFSDEBUG(format, args...) printf(format ,## args)
77 #else
78 #define NULLFSDEBUG(format, args...)
79 #endif /* NULLFS_DEBUG */
80 
81 #endif /* _KERNEL */
82