xref: /freebsd/sys/fs/nullfs/null.h (revision 66df505066f51e6d8411b966765d828817f88971)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1992, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software donated to Berkeley by
8  * Jan-Simon Pendry.
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 University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  *	@(#)null.h	8.3 (Berkeley) 8/20/94
35  *
36  * $FreeBSD$
37  */
38 
39 #ifndef	FS_NULL_H
40 #define	FS_NULL_H
41 
42 #define	NULLM_CACHE	0x0001
43 
44 struct null_mount {
45 	struct mount	*nullm_vfs;
46 	struct vnode	*nullm_lowerrootvp;	/* Ref to lower root vnode */
47 	uint64_t	nullm_flags;
48 	struct mount_upper_node upper_node;
49 	struct mount_upper_node notify_node;
50 };
51 
52 #ifdef _KERNEL
53 /*
54  * A cache of vnode references
55  */
56 struct null_node {
57 	LIST_ENTRY(null_node)	null_hash;	/* Hash list */
58 	struct vnode	        *null_lowervp;	/* VREFed once */
59 	struct vnode		*null_vnode;	/* Back pointer */
60 	u_int			null_flags;
61 };
62 
63 #define	NULLV_NOUNLOCK	0x0001
64 #define	NULLV_DROP	0x0002
65 
66 #define	MOUNTTONULLMOUNT(mp) ((struct null_mount *)((mp)->mnt_data))
67 #define	VTONULL(vp) ((struct null_node *)(vp)->v_data)
68 #define	NULLTOV(xp) ((xp)->null_vnode)
69 
70 int nullfs_init(struct vfsconf *vfsp);
71 int nullfs_uninit(struct vfsconf *vfsp);
72 int null_nodeget(struct mount *mp, struct vnode *target, struct vnode **vpp);
73 struct vnode *null_hashget(struct mount *mp, struct vnode *lowervp);
74 void null_hashrem(struct null_node *xp);
75 int null_bypass(struct vop_generic_args *ap);
76 
77 #ifdef DIAGNOSTIC
78 struct vnode *null_checkvp(struct vnode *vp, char *fil, int lno);
79 #define	NULLVPTOLOWERVP(vp) null_checkvp((vp), __FILE__, __LINE__)
80 #else
81 #define	NULLVPTOLOWERVP(vp) (VTONULL(vp)->null_lowervp)
82 #endif
83 
84 extern struct vop_vector null_vnodeops;
85 
86 #ifdef MALLOC_DECLARE
87 MALLOC_DECLARE(M_NULLFSNODE);
88 #endif
89 
90 #ifdef NULLFS_DEBUG
91 #define NULLFSDEBUG(format, args...) printf(format ,## args)
92 #else
93 #define NULLFSDEBUG(format, args...)
94 #endif /* NULLFS_DEBUG */
95 
96 #endif /* _KERNEL */
97 
98 #endif
99