xref: /netbsd/sys/miscfs/genfs/layer.h (revision 2d397e8e)
1 /*	$NetBSD: layer.h,v 1.17 2017/04/11 07:51:37 hannken Exp $	*/
2 
3 /*
4  * Copyright (c) 1999 National Aeronautics & Space Administration
5  * All rights reserved.
6  *
7  * This software was written by William Studenmund of the
8  * Numerical Aerospace Simulation Facility, NASA Ames Research Center.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the National Aeronautics & Space Administration
19  *    nor the names of its contributors may be used to endorse or promote
20  *    products derived from this software without specific prior written
21  *    permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE NATIONAL AERONAUTICS & SPACE ADMINISTRATION
24  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
25  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
26  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE ADMINISTRATION OR CONTRIB-
27  * UTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
28  * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
29  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
30  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
31  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
32  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
33  * POSSIBILITY OF SUCH DAMAGE.
34  */
35 
36 /*
37  * Copyright (c) 1992, 1993
38  *	The Regents of the University of California.  All rights reserved.
39  *
40  * This code is derived from software donated to Berkeley by
41  * Jan-Simon Pendry.
42  *
43  * Redistribution and use in source and binary forms, with or without
44  * modification, are permitted provided that the following conditions
45  * are met:
46  * 1. Redistributions of source code must retain the above copyright
47  *    notice, this list of conditions and the following disclaimer.
48  * 2. Redistributions in binary form must reproduce the above copyright
49  *    notice, this list of conditions and the following disclaimer in the
50  *    documentation and/or other materials provided with the distribution.
51  * 3. Neither the name of the University nor the names of its contributors
52  *    may be used to endorse or promote products derived from this software
53  *    without specific prior written permission.
54  *
55  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
56  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
57  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
58  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
59  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
60  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
61  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
62  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
63  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
64  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
65  * SUCH DAMAGE.
66  *
67  *	from: Id: lofs.h,v 1.8 1992/05/30 10:05:43 jsp Exp
68  *	@(#)null.h	8.2 (Berkeley) 1/21/94
69  */
70 
71 #ifndef _MISCFS_GENFS_LAYER_H_
72 #define _MISCFS_GENFS_LAYER_H_
73 
74 struct layer_args {
75 	char	*target;		/* Target of loopback  */
76 	struct export_args30 _pad1; /* compat with old userland tools */
77 };
78 
79 #ifdef _KERNEL
80 
81 struct layer_mount {
82 	struct vnode		*layerm_rootvp;	/* Ref to root layer_node */
83 	u_int			layerm_flags;	/* mount point layer flags */
84 	u_int			layerm_size;	/* size of fs's struct node */
85 	enum vtagtype		layerm_tag;	/* vtag of our vnodes */
86 	int				/* bypass routine for this mount */
87 				(*layerm_bypass)(void *);
88 	int			(**layerm_vnodeop_p)	/* ops for our nodes */
89 				(void *);
90 };
91 
92 #define	LAYERFS_MFLAGS		0x00000fff	/* reserved layer mount flags */
93 #define	LAYERFS_MBYPASSDEBUG	0x00000001
94 
95 /*
96  * A cache of vnode references
97  */
98 struct layer_node {
99 	struct vnode	        *layer_lowervp;	/* VREFed once */
100 	struct vnode		*layer_vnode;	/* Back pointer */
101 	unsigned int		layer_flags;	/* locking, etc. */
102 };
103 
104 #define	LAYERFS_RESFLAGS	0x00000fff	/* flags reserved for layerfs */
105 #define	LAYERFS_REMOVED 	0x00000001	/* Did a remove on this node */
106 
107 #define	LAYERFS_DO_BYPASS(vp, ap)	\
108 	(*MOUNTTOLAYERMOUNT((vp)->v_mount)->layerm_bypass)((ap))
109 
110 struct vnode *layer_checkvp(struct vnode *vp, const char *fil, int lno);
111 
112 #define	MOUNTTOLAYERMOUNT(mp) ((struct layer_mount *)((mp)->mnt_data))
113 #define	VTOLAYER(vp) ((struct layer_node *)(vp)->v_data)
114 #define	LAYERTOV(xp) ((xp)->layer_vnode)
115 #ifdef LAYERFS_DIAGNOSTIC
116 #define	LAYERVPTOLOWERVP(vp) layer_checkvp((vp), __FILE__, __LINE__)
117 extern int layerfs_debug;
118 #else
119 #define	LAYERVPTOLOWERVP(vp) (VTOLAYER(vp)->layer_lowervp)
120 #endif
121 
122 #endif /* _KERNEL */
123 #endif /* _MISCFS_GENFS_LAYER_H_ */
124