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 1.16 2004/11/18 20:04:26 dillon Exp $ 66 */ 67 68 #ifndef _SYS_NAMECACHE_H_ 69 #define _SYS_NAMECACHE_H_ 70 71 struct vnode; 72 73 TAILQ_HEAD(namecache_list, namecache); 74 75 /* 76 * The namecache structure is used to manage the filesystem namespace. Most 77 * vnodes cached by the system will reference one or more associated namecache 78 * structures. 79 * 80 * The namecache is disjoint, there may not always be a path to the system 81 * root through nc_parent links. If a namecache entry has no parent, that 82 * entry will not be hashed and can only be 'found' via '.' or '..'. 83 * 84 * Because the namecache structure maintains the path through mount points, 85 * null, and union mounts, and other VFS overlays, several namecache 86 * structures may pass through the same vnode. Also note that namespaces 87 * relating to non-existant (i.e. not-yet-created) files/directories may be 88 * locked. Lock coherency is achieved by requiring that the particular 89 * namecache record whos parent represents the physical directory in which 90 * the namespace operation is to occur be the one that is locked. In 91 * overlay cases, the (union, nullfs) VFS, or in namei when crossing a mount 92 * point, may have to obtain multiple namespace record locks to avoid 93 * confusion, but only the one representing the physical directory is passed 94 * into lower layer VOP calls. 95 * 96 * Many new API VOP operations do not pass vnodes. In these cases the 97 * operations vector is typically obtained via nc_mount->mnt_vn_ops. 98 */ 99 struct namecache { 100 LIST_ENTRY(namecache) nc_hash; /* hash chain (nc_parent,name) */ 101 TAILQ_ENTRY(namecache) nc_entry; /* scan via nc_parent->nc_list */ 102 TAILQ_ENTRY(namecache) nc_vnode; /* scan via vnode->v_namecache */ 103 struct namecache_list nc_list; /* list of children */ 104 struct namecache *nc_parent; /* namecache entry for parent */ 105 struct vnode *nc_vp; /* vnode representing name or NULL */ 106 int nc_refs; /* ref count prevents deletion */ 107 u_short nc_flag; 108 u_char nc_nlen; /* The length of the name, 255 max */ 109 u_char nc_unused; 110 char *nc_name; /* Separately allocated seg name */ 111 int nc_error; 112 int nc_timeout; /* compared against ticks, or 0 */ 113 int nc_exlocks; /* namespace locking */ 114 struct thread *nc_locktd; /* namespace locking */ 115 struct mount *nc_mount; /* associated mount for vopops */ 116 }; 117 118 typedef struct namecache *namecache_t; 119 120 /* 121 * Flags in namecache.nc_flag (u_char) 122 */ 123 #define NCF_LOCKED 0x0001 /* locked namespace */ 124 #define NCF_WHITEOUT 0x0002 /* negative entry corresponds to whiteout */ 125 #define NCF_UNRESOLVED 0x0004 /* invalid or unresolved entry */ 126 #define NCF_MOUNTPT 0x0008 /* mount point */ 127 #define NCF_ROOT 0x0010 /* namecache root (static) */ 128 #define NCF_HASHED 0x0020 /* namecache entry in hash table */ 129 #define NCF_LOCKREQ 0x0040 130 #define NCF_UNUSED080 0x0080 131 #define NCF_ISSYMLINK 0x0100 /* represents a symlink */ 132 #define NCF_ISDIR 0x0200 /* represents a directory */ 133 #define NCF_DESTROYED 0x0400 /* name association is considered destroyed */ 134 135 /* 136 * cache_inval[_vp]() flags 137 */ 138 #define CINV_DESTROY 0x0001 /* flag so cache_nlookup ignores the ncp */ 139 #define CINV_UNUSED02 0x0002 140 #define CINV_CHILDREN 0x0004 /* recursively set children to unresolved */ 141 142 #ifdef _KERNEL 143 144 struct vop_lookup_args; 145 struct componentname; 146 struct nlcomponent; 147 struct mount; 148 149 void cache_lock(struct namecache *ncp); 150 int cache_lock_nonblock(struct namecache *ncp); 151 void cache_unlock(struct namecache *ncp); 152 void cache_setvp(struct namecache *ncp, struct vnode *vp); 153 void cache_settimeout(struct namecache *ncp, int nticks); 154 void cache_setunresolved(struct namecache *ncp); 155 struct namecache *cache_nlookup(struct namecache *par, struct nlcomponent *nlc); 156 struct namecache *cache_allocroot(struct mount *mp, struct vnode *vp); 157 void cache_inval(struct namecache *ncp, int flags); 158 void cache_inval_vp(struct vnode *vp, int flags); 159 void vfs_cache_setroot(struct vnode *vp, struct namecache *ncp); 160 161 int cache_resolve(struct namecache *ncp, struct ucred *cred); 162 void cache_purge(struct vnode *vp); 163 void cache_purgevfs (struct mount *mp); 164 int cache_get_nonblock(struct namecache *ncp); 165 void cache_cleanneg(int count); 166 struct namecache *cache_get(struct namecache *ncp); 167 struct namecache *cache_hold(struct namecache *ncp); 168 void cache_put(struct namecache *ncp); 169 void cache_drop(struct namecache *ncp); 170 void cache_rename(struct namecache *fncp, struct namecache *tncp); 171 int cache_vget(struct namecache *, struct ucred *, int, struct vnode **); 172 int cache_vref(struct namecache *, struct ucred *, struct vnode **); 173 struct namecache *cache_fromdvp(struct vnode *, struct ucred *, int); 174 175 #endif 176 177 #endif 178