kernel - namecache MPSAFE work
[dragonfly.git] / sys / sys / namecache.h
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7ea21ed1 1/*
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2 * Copyright (c) 2003,2004 The DragonFly Project. All rights reserved.
3 *
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
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
15 * the documentation and/or other materials provided with the
16 * distribution.
17 * 3. Neither the name of The DragonFly Project nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific, prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
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34 * Copyright (c) 1989, 1993
35 * The Regents of the University of California. All rights reserved.
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36 *
37 * Redistribution and use in source and binary forms, with or without
38 * modification, are permitted provided that the following conditions
39 * are met:
40 * 1. Redistributions of source code must retain the above copyright
41 * notice, this list of conditions and the following disclaimer.
42 * 2. Redistributions in binary form must reproduce the above copyright
43 * notice, this list of conditions and the following disclaimer in the
44 * documentation and/or other materials provided with the distribution.
45 * 3. All advertising materials mentioning features or use of this software
46 * must display the following acknowledgement:
47 * This product includes software developed by the University of
48 * California, Berkeley and its contributors.
49 * 4. Neither the name of the University nor the names of its contributors
50 * may be used to endorse or promote products derived from this software
51 * without specific prior written permission.
52 *
53 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
54 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
55 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
56 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
57 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
58 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
59 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
60 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
61 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
62 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
63 * SUCH DAMAGE.
64 *
5312fa43 65 * $DragonFly: src/sys/sys/namecache.h,v 1.31 2008/05/09 17:52:18 dillon Exp $
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66 */
67
68#ifndef _SYS_NAMECACHE_H_
69#define _SYS_NAMECACHE_H_
70
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71#ifndef _SYS_TYPES_H_
72#include <sys/types.h>
73#endif
74#ifndef _SYS_QUEUE_H_
75#include <sys/queue.h>
76#endif
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77#ifndef _SYS_SPINLOCK_H_
78#include <sys/spinlock.h>
79#endif
80#ifndef _SYS_THREAD_H_
81#include <sys/thread.h>
82#endif
1bd40720 83
7ea21ed1 84struct vnode;
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85struct ucred;
86struct proc;
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87
88TAILQ_HEAD(namecache_list, namecache);
89
90/*
91 * The namecache structure is used to manage the filesystem namespace. Most
92 * vnodes cached by the system will reference one or more associated namecache
93 * structures.
94 *
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95 * The namecache is disjoint, there may not always be a path to the system
96 * root through nc_parent links. If a namecache entry has no parent, that
97 * entry will not be hashed and can only be 'found' via '.' or '..'.
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98 *
99 * Because the namecache structure maintains the path through mount points,
100 * null, and union mounts, and other VFS overlays, several namecache
101 * structures may pass through the same vnode. Also note that namespaces
102 * relating to non-existant (i.e. not-yet-created) files/directories may be
103 * locked. Lock coherency is achieved by requiring that the particular
104 * namecache record whos parent represents the physical directory in which
105 * the namespace operation is to occur be the one that is locked. In
106 * overlay cases, the (union, nullfs) VFS, or in namei when crossing a mount
107 * point, may have to obtain multiple namespace record locks to avoid
108 * confusion, but only the one representing the physical directory is passed
109 * into lower layer VOP calls.
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110 *
111 * Many new API VOP operations do not pass vnodes. In these cases the
6ddb7618 112 * operations vector is typically obtained via nc_mount->mnt_vn_use_ops.
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113 */
114struct namecache {
115 LIST_ENTRY(namecache) nc_hash; /* hash chain (nc_parent,name) */
116 TAILQ_ENTRY(namecache) nc_entry; /* scan via nc_parent->nc_list */
117 TAILQ_ENTRY(namecache) nc_vnode; /* scan via vnode->v_namecache */
118 struct namecache_list nc_list; /* list of children */
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119 struct nchash_head *nc_head;
120 struct namecache *nc_parent; /* namecache entry for parent */
121 struct vnode *nc_vp; /* vnode representing name or NULL */
122 int nc_refs; /* ref count prevents deletion */
123 u_short nc_flag;
124 u_char nc_nlen; /* The length of the name, 255 max */
125 u_char nc_lockreq;
126 char *nc_name; /* Separately allocated seg name */
127 int nc_error;
128 int nc_timeout; /* compared against ticks, or 0 */
129 int nc_exlocks; /* namespace locking */
130 struct thread *nc_locktd; /* namespace locking */
131 long nc_namecache_gen; /* cmp against mnt_namecache_gen */
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132};
133
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134/*
135 * Namecache handles include a mount reference allowing topologies
136 * to be replicated with mount overlays (nullfs mounts).
137 */
138struct nchandle {
139 struct namecache *ncp; /* ncp in underlying filesystem */
140 struct mount *mount; /* mount pt (possible overlay) */
141};
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142
143/*
144 * Flags in namecache.nc_flag (u_char)
145 */
f63911bf 146#define NCF_UNUSED01 0x0001
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147#define NCF_WHITEOUT 0x0002 /* negative entry corresponds to whiteout */
148#define NCF_UNRESOLVED 0x0004 /* invalid or unresolved entry */
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149#define NCF_ISMOUNTPT 0x0008 /* someone may have mounted on us here */
150#define NCF_UNUSED10 0x0010
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151#define NCF_UNUSED20 0x0020
152#define NCF_UNUSED40 0x0040
153#define NCF_UNUSED80 0x0080
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154#define NCF_ISSYMLINK 0x0100 /* represents a symlink */
155#define NCF_ISDIR 0x0200 /* represents a directory */
e09206ba 156#define NCF_DESTROYED 0x0400 /* name association is considered destroyed */
d98152a8 157#define NCF_UNUSED800 0x0800
7ea21ed1 158
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159/*
160 * cache_inval[_vp]() flags
161 */
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162#define CINV_DESTROY 0x0001 /* flag so cache_nlookup ignores the ncp */
163#define CINV_UNUSED02 0x0002
164#define CINV_CHILDREN 0x0004 /* recursively set children to unresolved */
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165
166#ifdef _KERNEL
167
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168extern struct lwkt_token vfs_token;
169
7ea21ed1 170struct componentname;
690a3127 171struct nlcomponent;
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172struct mount;
173
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174void cache_lock(struct nchandle *nch);
175int cache_lock_nonblock(struct nchandle *nch);
176void cache_unlock(struct nchandle *nch);
177void cache_setvp(struct nchandle *nch, struct vnode *vp);
178void cache_settimeout(struct nchandle *nch, int nticks);
179void cache_setunresolved(struct nchandle *nch);
180void cache_clrmountpt(struct nchandle *nch);
181struct nchandle cache_nlookup(struct nchandle *nch, struct nlcomponent *nlc);
182void cache_allocroot(struct nchandle *nch, struct mount *mp, struct vnode *vp);
183struct mount *cache_findmount(struct nchandle *nch);
184int cache_inval(struct nchandle *nch, int flags);
6b008938 185int cache_inval_vp(struct vnode *vp, int flags);
5c6c3cac 186int cache_inval_vp_nonblock(struct vnode *vp);
28623bf9 187void vfs_cache_setroot(struct vnode *vp, struct nchandle *nch);
1d505369 188
28623bf9 189int cache_resolve(struct nchandle *nch, struct ucred *cred);
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190void cache_purge(struct vnode *vp);
191void cache_purgevfs (struct mount *mp);
f63911bf 192int cache_get_nonblock(struct nchandle *nch, struct nchandle *target);
62d0f1f0 193void cache_cleanneg(int count);
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194void cache_get(struct nchandle *nch, struct nchandle *target);
195struct nchandle *cache_hold(struct nchandle *nch);
196void cache_copy(struct nchandle *nch, struct nchandle *target);
197void cache_changemount(struct nchandle *nch, struct mount *mp);
198void cache_put(struct nchandle *nch);
199void cache_drop(struct nchandle *nch);
200void cache_zero(struct nchandle *nch);
201void cache_rename(struct nchandle *fnch, struct nchandle *tnch);
202int cache_vget(struct nchandle *, struct ucred *, int, struct vnode **);
203int cache_vref(struct nchandle *, struct ucred *, struct vnode **);
204int cache_fromdvp(struct vnode *, struct ucred *, int, struct nchandle *);
205int cache_fullpath(struct proc *, struct nchandle *, char **, char **);
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206
207#endif
208
209#endif