| 1 | /* |
| 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 | * |
| 34 | * Copyright (c) 1989, 1993 |
| 35 | * The Regents of the University of California. All rights reserved. |
| 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 | * |
| 65 | * $DragonFly: src/sys/sys/namecache.h,v 1.31 2008/05/09 17:52:18 dillon Exp $ |
| 66 | */ |
| 67 | |
| 68 | #ifndef _SYS_NAMECACHE_H_ |
| 69 | #define _SYS_NAMECACHE_H_ |
| 70 | |
| 71 | #ifndef _SYS_TYPES_H_ |
| 72 | #include <sys/types.h> |
| 73 | #endif |
| 74 | #ifndef _SYS_QUEUE_H_ |
| 75 | #include <sys/queue.h> |
| 76 | #endif |
| 77 | #ifndef _SYS_SPINLOCK_H_ |
| 78 | #include <sys/spinlock.h> |
| 79 | #endif |
| 80 | #ifndef _SYS_THREAD_H_ |
| 81 | #include <sys/thread.h> |
| 82 | #endif |
| 83 | |
| 84 | struct vnode; |
| 85 | struct ucred; |
| 86 | struct proc; |
| 87 | |
| 88 | TAILQ_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 | * |
| 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 '..'. |
| 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. |
| 110 | * |
| 111 | * Many new API VOP operations do not pass vnodes. In these cases the |
| 112 | * operations vector is typically obtained via nc_mount->mnt_vn_use_ops. |
| 113 | */ |
| 114 | struct 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 */ |
| 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 */ |
| 132 | }; |
| 133 | |
| 134 | /* |
| 135 | * Namecache handles include a mount reference allowing topologies |
| 136 | * to be replicated with mount overlays (nullfs mounts). |
| 137 | */ |
| 138 | struct nchandle { |
| 139 | struct namecache *ncp; /* ncp in underlying filesystem */ |
| 140 | struct mount *mount; /* mount pt (possible overlay) */ |
| 141 | }; |
| 142 | |
| 143 | /* |
| 144 | * Flags in namecache.nc_flag (u_char) |
| 145 | */ |
| 146 | #define NCF_UNUSED01 0x0001 |
| 147 | #define NCF_WHITEOUT 0x0002 /* negative entry corresponds to whiteout */ |
| 148 | #define NCF_UNRESOLVED 0x0004 /* invalid or unresolved entry */ |
| 149 | #define NCF_ISMOUNTPT 0x0008 /* someone may have mounted on us here */ |
| 150 | #define NCF_UNUSED10 0x0010 |
| 151 | #define NCF_UNUSED20 0x0020 |
| 152 | #define NCF_UNUSED40 0x0040 |
| 153 | #define NCF_UNUSED80 0x0080 |
| 154 | #define NCF_ISSYMLINK 0x0100 /* represents a symlink */ |
| 155 | #define NCF_ISDIR 0x0200 /* represents a directory */ |
| 156 | #define NCF_DESTROYED 0x0400 /* name association is considered destroyed */ |
| 157 | #define NCF_UNUSED800 0x0800 |
| 158 | |
| 159 | /* |
| 160 | * cache_inval[_vp]() flags |
| 161 | */ |
| 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 */ |
| 165 | |
| 166 | #ifdef _KERNEL |
| 167 | |
| 168 | extern struct lwkt_token vfs_token; |
| 169 | |
| 170 | struct componentname; |
| 171 | struct nlcomponent; |
| 172 | struct mount; |
| 173 | |
| 174 | void cache_lock(struct nchandle *nch); |
| 175 | int cache_lock_nonblock(struct nchandle *nch); |
| 176 | void cache_unlock(struct nchandle *nch); |
| 177 | void cache_setvp(struct nchandle *nch, struct vnode *vp); |
| 178 | void cache_settimeout(struct nchandle *nch, int nticks); |
| 179 | void cache_setunresolved(struct nchandle *nch); |
| 180 | void cache_clrmountpt(struct nchandle *nch); |
| 181 | struct nchandle cache_nlookup(struct nchandle *nch, struct nlcomponent *nlc); |
| 182 | void cache_allocroot(struct nchandle *nch, struct mount *mp, struct vnode *vp); |
| 183 | struct mount *cache_findmount(struct nchandle *nch); |
| 184 | int cache_inval(struct nchandle *nch, int flags); |
| 185 | int cache_inval_vp(struct vnode *vp, int flags); |
| 186 | int cache_inval_vp_nonblock(struct vnode *vp); |
| 187 | void vfs_cache_setroot(struct vnode *vp, struct nchandle *nch); |
| 188 | |
| 189 | int cache_resolve(struct nchandle *nch, struct ucred *cred); |
| 190 | void cache_purge(struct vnode *vp); |
| 191 | void cache_purgevfs (struct mount *mp); |
| 192 | int cache_get_nonblock(struct nchandle *nch, struct nchandle *target); |
| 193 | void cache_cleanneg(int count); |
| 194 | void cache_get(struct nchandle *nch, struct nchandle *target); |
| 195 | struct nchandle *cache_hold(struct nchandle *nch); |
| 196 | void cache_copy(struct nchandle *nch, struct nchandle *target); |
| 197 | void cache_changemount(struct nchandle *nch, struct mount *mp); |
| 198 | void cache_put(struct nchandle *nch); |
| 199 | void cache_drop(struct nchandle *nch); |
| 200 | void cache_zero(struct nchandle *nch); |
| 201 | void cache_rename(struct nchandle *fnch, struct nchandle *tnch); |
| 202 | int cache_vget(struct nchandle *, struct ucred *, int, struct vnode **); |
| 203 | int cache_vref(struct nchandle *, struct ucred *, struct vnode **); |
| 204 | int cache_fromdvp(struct vnode *, struct ucred *, int, struct nchandle *); |
| 205 | int cache_fullpath(struct proc *, struct nchandle *, char **, char **); |
| 206 | |
| 207 | #endif |
| 208 | |
| 209 | #endif |