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
35 #ifndef FS_NULL_H
36 #define FS_NULL_H
37
38 #include <sys/ck.h>
39 #include <vm/uma.h>
40
41 #define NULLM_CACHE 0x0001
42 #define NULLM_NOUNPBYPASS 0x0002
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 CK_SLIST_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 VTONULL_SMR(vp) ((struct null_node *)vn_load_v_data_smr(vp))
69 #define NULLTOV(xp) ((xp)->null_vnode)
70
71 int nullfs_init(struct vfsconf *vfsp);
72 int nullfs_uninit(struct vfsconf *vfsp);
73 int null_nodeget(struct mount *mp, struct vnode *target, struct vnode **vpp);
74 struct vnode *null_hashget(struct mount *mp, struct vnode *lowervp);
75 void null_hashrem(struct null_node *xp);
76 int null_bypass(struct vop_generic_args *ap);
77
78 #ifdef DIAGNOSTIC
79 struct vnode *null_checkvp(struct vnode *vp, char *fil, int lno);
80 #define NULLVPTOLOWERVP(vp) null_checkvp((vp), __FILE__, __LINE__)
81 #else
82 #define NULLVPTOLOWERVP(vp) (VTONULL(vp)->null_lowervp)
83 #endif
84
85 extern struct vop_vector null_vnodeops;
86 extern struct vop_vector null_vnodeops_no_unp_bypass;
87
88 static inline bool
null_is_nullfs_vnode(struct vnode * vp)89 null_is_nullfs_vnode(struct vnode *vp)
90 {
91 const struct vop_vector *op;
92
93 op = vp->v_op;
94 return (op == &null_vnodeops || op == &null_vnodeops_no_unp_bypass);
95 }
96
97 extern uma_zone_t null_node_zone;
98
99 #ifdef NULLFS_DEBUG
100 #define NULLFSDEBUG(format, args...) printf(format ,## args)
101 #else
102 #define NULLFSDEBUG(format, args...)
103 #endif /* NULLFS_DEBUG */
104
105 #endif /* _KERNEL */
106
107 #endif
108