1 /* 2 * Copyright (c) 2003,2004-2019 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. Neither the name of the University nor the names of its contributors 46 * may be used to endorse or promote products derived from this software 47 * without specific prior written permission. 48 * 49 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 50 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 51 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 52 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 53 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 54 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 55 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 56 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 57 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 58 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 59 * SUCH DAMAGE. 60 */ 61 62 #ifndef _SYS_NAMECACHE_H_ 63 #define _SYS_NAMECACHE_H_ 64 65 #ifndef _SYS_TYPES_H_ 66 #include <sys/types.h> 67 #endif 68 #ifndef _SYS_LOCK_H_ 69 #include <sys/lock.h> 70 #endif 71 #ifndef _SYS_QUEUE_H_ 72 #include <sys/queue.h> 73 #endif 74 #ifndef _SYS_SPINLOCK_H_ 75 #include <sys/spinlock.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 DragonFly namecache maintains elements from active nodes to the root 90 * in all but the NFS server case and the removed file/directory case. 91 * NFS servers use fhtovp() and may have to regenerate the topology to 92 * the leaf on the fly. 93 * 94 * Because the namecache structure maintains the path through mount points, 95 * null, and union mounts, and other VFS overlays, several namecache 96 * structures may pass through the same vnode. Also note that namespaces 97 * relating to non-existant (i.e. not-yet-created) files/directories may be 98 * locked. Lock coherency is achieved by requiring that the particular 99 * namecache record whos parent represents the physical directory in which 100 * the namespace operation is to occur be the one that is locked. In 101 * overlay cases, the (union, nullfs) VFS, or in namei when crossing a mount 102 * point, may have to obtain multiple namespace record locks to avoid 103 * confusion, but only the one representing the physical directory is passed 104 * into lower layer VOP calls. 105 * 106 * ncp locking is done using atomic ops on nc_lockstatus, including a request 107 * flag for waiters. nc_locktd is set after locking or cleared before 108 * the last unlock. ncp locks are reentrant. 109 * 110 * Many new API VOP operations do not pass vnodes. In these cases the 111 * operations vector is typically obtained via nc_mount->mnt_vn_use_ops. 112 */ 113 struct namecache { 114 TAILQ_ENTRY(namecache) nc_hash; /* hash chain (nc_parent,name) */ 115 TAILQ_ENTRY(namecache) nc_entry; /* scan via nc_parent->nc_list */ 116 TAILQ_ENTRY(namecache) nc_vnode; /* scan via vnode->v_namecache */ 117 struct namecache_list nc_list; /* list of children */ 118 struct nchash_head *nc_head; 119 struct namecache *nc_parent; /* namecache entry for parent */ 120 struct vnode *nc_vp; /* vnode representing name or NULL */ 121 u_short nc_flag; 122 u_char nc_nlen; /* The length of the name, 255 max */ 123 u_char nc_unused; 124 char *nc_name; /* Separately allocated seg name */ 125 int nc_error; 126 int nc_timeout; /* compared against ticks, or 0 */ 127 int nc_negcpu; /* which ncneg list are we on? */ 128 struct { 129 u_int nc_namecache_gen; /* mount generation (autoclear) */ 130 u_int nc_generation; /* rename/unlink generation */ 131 int nc_refs; /* ref count prevents deletion */ 132 } __cachealign; 133 struct { 134 struct lock nc_lock; 135 } __cachealign; 136 }; 137 138 /* 139 * Namecache handles include a mount reference allowing topologies 140 * to be replicated with mount overlays (nullfs mounts). 141 */ 142 struct nchandle { 143 struct namecache *ncp; /* ncp in underlying filesystem */ 144 struct mount *mount; /* mount pt (possible overlay) */ 145 }; 146 147 /* 148 * Flags in namecache.nc_flag (u_short) 149 */ 150 #define NCF_NOTX 0x0001 /* 'x' bit not set in user, group, or world */ 151 #define NCF_WHITEOUT 0x0002 /* negative entry corresponds to whiteout */ 152 #define NCF_UNRESOLVED 0x0004 /* invalid or unresolved entry */ 153 #define NCF_ISMOUNTPT 0x0008 /* someone may have mounted on us here */ 154 #define NCF_SF_NOCACHE 0x0010 /* track swapcache chflags from attr */ 155 #define NCF_UF_CACHE 0x0020 156 #define NCF_SF_PNOCACHE 0x0040 /* track from parent */ 157 #define NCF_UF_PCACHE 0x0080 158 #define NCF_ISSYMLINK 0x0100 /* represents a symlink */ 159 #define NCF_ISDIR 0x0200 /* represents a directory */ 160 #define NCF_DESTROYED 0x0400 /* name association is considered destroyed */ 161 #define NCF_DEFEREDZAP 0x0800 /* zap defered due to lock unavailability */ 162 #define NCF_WXOK 0x1000 /* world-searchable (nlookup shortcut) */ 163 #define NCF_DUMMY 0x2000 /* dummy ncp, iterations ignore it */ 164 165 /* 166 * cache_inval[_vp]() flags 167 */ 168 #define CINV_DESTROY 0x0001 /* flag so cache_nlookup ignores the ncp */ 169 #define CINV_UNUSED02 0x0002 170 #define CINV_CHILDREN 0x0004 /* recursively set children to unresolved */ 171 172 #ifdef _KERNEL 173 174 struct componentname; 175 struct nlcomponent; 176 struct mount; 177 178 void cache_clearmntcache(struct mount *mp); 179 void cache_lock(struct nchandle *nch); 180 void cache_lock_maybe_shared(struct nchandle *nch, int excl); 181 void cache_lock4_tondlocked(struct nchandle *fncpd, struct nchandle *fncp, 182 struct nchandle *tncpd, struct nchandle *tncp, 183 struct ucred *fcred, struct ucred *tcred); 184 int cache_lock_nonblock(struct nchandle *nch); 185 void cache_unlock(struct nchandle *nch); 186 int cache_lockstatus(struct nchandle *nch); 187 void cache_setvp(struct nchandle *nch, struct vnode *vp); 188 void cache_settimeout(struct nchandle *nch, int nticks); 189 void cache_setunresolved(struct nchandle *nch); 190 void cache_clrmountpt(struct nchandle *nch); 191 struct nchandle cache_nlookup(struct nchandle *nch, 192 struct nlcomponent *nlc); 193 struct nchandle cache_nlookup_nonblock(struct nchandle *nch, 194 struct nlcomponent *nlc); 195 struct nchandle cache_nlookup_nonlocked(struct nchandle *nch, 196 struct nlcomponent *nlc); 197 int cache_nlookup_maybe_shared(struct nchandle *nch, 198 struct nlcomponent *nlc, int excl, 199 struct nchandle *nchres); 200 void cache_allocroot(struct nchandle *nch, struct mount *mp, struct vnode *vp); 201 struct mount *cache_findmount(struct nchandle *nch); 202 void cache_dropmount(struct mount *mp); 203 void cache_ismounting(struct mount *mp); 204 void cache_unmounting(struct mount *mp); 205 int cache_inval(struct nchandle *nch, int flags); 206 int cache_inval_vp(struct vnode *vp, int flags); 207 int cache_inval_vp_nonblock(struct vnode *vp); 208 void cache_inval_wxok(struct vnode *vp); 209 void vfs_cache_setroot(struct vnode *vp, struct nchandle *nch); 210 211 int cache_resolve(struct nchandle *nch, struct ucred *cred); 212 int cache_resolve_dvp(struct nchandle *nch, struct ucred *cred, 213 struct vnode **dvpp); 214 void cache_purge(struct vnode *vp); 215 void cache_purgevfs (struct mount *mp); 216 void cache_hysteresis(int critpath); 217 void cache_get(struct nchandle *nch, struct nchandle *target); 218 int cache_get_nonblock(struct nchandle *nch, int elmno, 219 struct nchandle *target); 220 void cache_get_maybe_shared(struct nchandle *nch, 221 struct nchandle *target, int excl); 222 struct nchandle *cache_hold(struct nchandle *nch); 223 void cache_copy(struct nchandle *nch, struct nchandle *target); 224 void cache_changemount(struct nchandle *nch, struct mount *mp); 225 void cache_put(struct nchandle *nch); 226 void cache_drop(struct nchandle *nch); 227 void cache_drop_and_cache(struct nchandle *nch, int elmno); 228 void cache_zero(struct nchandle *nch); 229 void cache_rename(struct nchandle *fnch, struct nchandle *tnch); 230 void cache_unlink(struct nchandle *nch); 231 int cache_isopen(struct nchandle *nch); 232 int cache_vget(struct nchandle *, struct ucred *, int, struct vnode **); 233 int cache_vref(struct nchandle *, struct ucred *, struct vnode **); 234 int cache_fromdvp(struct vnode *, struct ucred *, int, struct nchandle *); 235 int cache_fullpath(struct proc *, struct nchandle *, struct nchandle *, 236 char **, char **, int); 237 void vfscache_rollup_cpu(struct globaldata *gd); 238 struct vnode *cache_dvpref(struct namecache *ncp); 239 240 #endif 241 242 #endif 243