xref: /freebsd/sys/fs/nullfs/null.h (revision a1a4f1a0d87b594d3f17a97dc0127eec1417e6f6)
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  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by the University of
19  *	California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  *
36  *	@(#)null.h	8.3 (Berkeley) 8/20/94
37  *
38  * $FreeBSD$
39  */
40 
41 struct null_args {
42 	char		*target;	/* Target of loopback  */
43 };
44 
45 struct null_mount {
46 	struct mount	*nullm_vfs;
47 	struct vnode	*nullm_rootvp;	/* Reference to root null_node */
48 };
49 
50 #ifdef KERNEL
51 /*
52  * A cache of vnode references
53  */
54 struct null_node {
55 	LIST_ENTRY(null_node)	null_hash;	/* Hash list */
56 	struct vnode	        *null_lowervp;	/* VREFed once */
57 	struct vnode		*null_vnode;	/* Back pointer */
58 };
59 
60 extern int nullfs_init __P((struct vfsconf *vfsp));
61 extern int null_node_create __P((struct mount *mp, struct vnode *target, struct vnode **vpp));
62 
63 #define	MOUNTTONULLMOUNT(mp) ((struct null_mount *)((mp)->mnt_data))
64 #define	VTONULL(vp) ((struct null_node *)(vp)->v_data)
65 #define	NULLTOV(xp) ((xp)->null_vnode)
66 #ifdef NULLFS_DIAGNOSTIC
67 extern struct vnode *null_checkvp __P((struct vnode *vp, char *fil, int lno));
68 #define	NULLVPTOLOWERVP(vp) null_checkvp((vp), __FILE__, __LINE__)
69 #else
70 #define	NULLVPTOLOWERVP(vp) (VTONULL(vp)->null_lowervp)
71 #endif
72 
73 extern int	null_bypass __P((struct vop_generic_args *ap));
74 
75 extern vop_t **null_vnodeop_p;
76 #endif /* KERNEL */
77