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 78 struct vnode; 79 struct ucred; 80 struct proc; 81 82 TAILQ_HEAD(namecache_list, namecache); 83 84 /* 85 * The namecache structure is used to manage the filesystem namespace. Most 86 * vnodes cached by the system will reference one or more associated namecache 87 * structures. 88 * 89 * The namecache is disjoint, there may not always be a path to the system 90 * root through nc_parent links. If a namecache entry has no parent, that 91 * entry will not be hashed and can only be 'found' via '.' or '..'. 92 * 93 * Because the namecache structure maintains the path through mount points, 94 * null, and union mounts, and other VFS overlays, several namecache 95 * structures may pass through the same vnode. Also note that namespaces 96 * relating to non-existant (i.e. not-yet-created) files/directories may be 97 * locked. Lock coherency is achieved by requiring that the particular 98 * namecache record whos parent represents the physical directory in which 99 * the namespace operation is to occur be the one that is locked. In 100 * overlay cases, the (union, nullfs) VFS, or in namei when crossing a mount 101 * point, may have to obtain multiple namespace record locks to avoid 102 * confusion, but only the one representing the physical directory is passed 103 * into lower layer VOP calls. 104 * 105 * Many new API VOP operations do not pass vnodes. In these cases the 106 * operations vector is typically obtained via nc_mount->mnt_vn_use_ops. 107 */ 108 struct namecache { 109 LIST_ENTRY(namecache) nc_hash; /* hash chain (nc_parent,name) */ 110 TAILQ_ENTRY(namecache) nc_entry; /* scan via nc_parent->nc_list */ 111 TAILQ_ENTRY(namecache) nc_vnode; /* scan via vnode->v_namecache */ 112 struct namecache_list nc_list; /* list of children */ 113 struct namecache *nc_parent; /* namecache entry for parent */ 114 struct vnode *nc_vp; /* vnode representing name or NULL */ 115 int nc_refs; /* ref count prevents deletion */ 116 u_short nc_flag; 117 u_char nc_nlen; /* The length of the name, 255 max */ 118 u_char nc_unused; 119 char *nc_name; /* Separately allocated seg name */ 120 int nc_error; 121 int nc_timeout; /* compared against ticks, or 0 */ 122 int nc_exlocks; /* namespace locking */ 123 struct thread *nc_locktd; /* namespace locking */ 124 int64_t nc_fsmid; /* filesystem modified id */ 125 long nc_namecache_gen; /* cmp against mnt_namecache_gen */ 126 }; 127 128 /* 129 * Namecache handles include a mount reference allowing topologies 130 * to be replicated with mount overlays (nullfs mounts). 131 */ 132 struct nchandle { 133 struct namecache *ncp; /* ncp in underlying filesystem */ 134 struct mount *mount; /* mount pt (possible overlay) */ 135 }; 136 137 /* 138 * Flags in namecache.nc_flag (u_char) 139 */ 140 #define NCF_LOCKED 0x0001 /* locked namespace */ 141 #define NCF_WHITEOUT 0x0002 /* negative entry corresponds to whiteout */ 142 #define NCF_UNRESOLVED 0x0004 /* invalid or unresolved entry */ 143 #define NCF_ISMOUNTPT 0x0008 /* someone may have mounted on us here */ 144 #define NCF_UNUSED10 0x0010 145 #define NCF_HASHED 0x0020 /* namecache entry in hash table */ 146 #define NCF_LOCKREQ 0x0040 147 #define NCF_UNUSED20 0x0080 148 #define NCF_ISSYMLINK 0x0100 /* represents a symlink */ 149 #define NCF_ISDIR 0x0200 /* represents a directory */ 150 #define NCF_DESTROYED 0x0400 /* name association is considered destroyed */ 151 #define NCF_FSMID 0x0800 /* FSMID updated */ 152 153 /* 154 * cache_inval[_vp]() flags 155 */ 156 #define CINV_DESTROY 0x0001 /* flag so cache_nlookup ignores the ncp */ 157 #define CINV_UNUSED02 0x0002 158 #define CINV_CHILDREN 0x0004 /* recursively set children to unresolved */ 159 160 #ifdef _KERNEL 161 162 struct componentname; 163 struct nlcomponent; 164 struct mount; 165 166 void cache_lock(struct nchandle *nch); 167 int cache_lock_nonblock(struct nchandle *nch); 168 void cache_unlock(struct nchandle *nch); 169 void cache_setvp(struct nchandle *nch, struct vnode *vp); 170 void cache_settimeout(struct nchandle *nch, int nticks); 171 void cache_setunresolved(struct nchandle *nch); 172 void cache_clrmountpt(struct nchandle *nch); 173 struct nchandle cache_nlookup(struct nchandle *nch, struct nlcomponent *nlc); 174 void cache_allocroot(struct nchandle *nch, struct mount *mp, struct vnode *vp); 175 struct mount *cache_findmount(struct nchandle *nch); 176 int cache_inval(struct nchandle *nch, int flags); 177 int cache_inval_vp(struct vnode *vp, int flags); 178 int cache_inval_vp_nonblock(struct vnode *vp); 179 void vfs_cache_setroot(struct vnode *vp, struct nchandle *nch); 180 181 int cache_resolve(struct nchandle *nch, struct ucred *cred); 182 void cache_purge(struct vnode *vp); 183 void cache_purgevfs (struct mount *mp); 184 int cache_get_nonblock(struct nchandle *nch); 185 void cache_cleanneg(int count); 186 void cache_get(struct nchandle *nch, struct nchandle *target); 187 struct nchandle *cache_hold(struct nchandle *nch); 188 void cache_copy(struct nchandle *nch, struct nchandle *target); 189 void cache_changemount(struct nchandle *nch, struct mount *mp); 190 void cache_put(struct nchandle *nch); 191 void cache_drop(struct nchandle *nch); 192 void cache_zero(struct nchandle *nch); 193 void cache_rename(struct nchandle *fnch, struct nchandle *tnch); 194 int cache_vget(struct nchandle *, struct ucred *, int, struct vnode **); 195 int cache_vref(struct nchandle *, struct ucred *, struct vnode **); 196 int cache_fromdvp(struct vnode *, struct ucred *, int, struct nchandle *); 197 int cache_fullpath(struct proc *, struct nchandle *, char **, char **); 198 void cache_update_fsmid(struct nchandle *); 199 void cache_update_fsmid_vp(struct vnode *); 200 int64_t cache_sync_fsmid_vp(struct vnode *); 201 int cache_check_fsmid_vp(struct vnode *, int64_t *); 202 int64_t cache_getnewfsmid(void); 203 204 #endif 205 206 #endif 207