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 DragonFly namecache maintains elements from active nodes to the root 96 * in all but the NFS server case and the removed file/directory case. 97 * NFS servers use fhtovp() and may have to regenerate the topology to 98 * the leaf on the fly. 99 * 100 * Because the namecache structure maintains the path through mount points, 101 * null, and union mounts, and other VFS overlays, several namecache 102 * structures may pass through the same vnode. Also note that namespaces 103 * relating to non-existant (i.e. not-yet-created) files/directories may be 104 * locked. Lock coherency is achieved by requiring that the particular 105 * namecache record whos parent represents the physical directory in which 106 * the namespace operation is to occur be the one that is locked. In 107 * overlay cases, the (union, nullfs) VFS, or in namei when crossing a mount 108 * point, may have to obtain multiple namespace record locks to avoid 109 * confusion, but only the one representing the physical directory is passed 110 * into lower layer VOP calls. 111 * 112 * ncp locking is done using atomic ops on nc_exlocks, including a request 113 * flag for waiters. nc_locktd is set after locking or cleared before 114 * the last unlock. ncp locks are reentrant. 115 * 116 * Many new API VOP operations do not pass vnodes. In these cases the 117 * operations vector is typically obtained via nc_mount->mnt_vn_use_ops. 118 */ 119 struct namecache { 120 LIST_ENTRY(namecache) nc_hash; /* hash chain (nc_parent,name) */ 121 TAILQ_ENTRY(namecache) nc_entry; /* scan via nc_parent->nc_list */ 122 TAILQ_ENTRY(namecache) nc_vnode; /* scan via vnode->v_namecache */ 123 struct namecache_list nc_list; /* list of children */ 124 struct nchash_head *nc_head; 125 struct namecache *nc_parent; /* namecache entry for parent */ 126 struct vnode *nc_vp; /* vnode representing name or NULL */ 127 int nc_refs; /* ref count prevents deletion */ 128 u_short nc_flag; 129 u_char nc_nlen; /* The length of the name, 255 max */ 130 u_char nc_unused; 131 char *nc_name; /* Separately allocated seg name */ 132 int nc_error; 133 int nc_timeout; /* compared against ticks, or 0 */ 134 u_int nc_exlocks; /* namespace locking */ 135 struct thread *nc_locktd; /* namespace locking */ 136 long nc_namecache_gen; /* cmp against mnt_namecache_gen */ 137 }; 138 139 /* 140 * Namecache handles include a mount reference allowing topologies 141 * to be replicated with mount overlays (nullfs mounts). 142 */ 143 struct nchandle { 144 struct namecache *ncp; /* ncp in underlying filesystem */ 145 struct mount *mount; /* mount pt (possible overlay) */ 146 }; 147 148 #define ASSERT_NCH_LOCKED(nch) KKASSERT(nch->ncp->nc_locktd == curthread) 149 150 /* 151 * Flags in namecache.nc_flag (u_char) 152 */ 153 #define NCF_UNUSED01 0x0001 154 #define NCF_WHITEOUT 0x0002 /* negative entry corresponds to whiteout */ 155 #define NCF_UNRESOLVED 0x0004 /* invalid or unresolved entry */ 156 #define NCF_ISMOUNTPT 0x0008 /* someone may have mounted on us here */ 157 #define NCF_SF_NOCACHE 0x0010 /* track swapcache chflags from attr */ 158 #define NCF_UF_CACHE 0x0020 159 #define NCF_SF_PNOCACHE 0x0040 /* track from parent */ 160 #define NCF_UF_PCACHE 0x0080 161 #define NCF_ISSYMLINK 0x0100 /* represents a symlink */ 162 #define NCF_ISDIR 0x0200 /* represents a directory */ 163 #define NCF_DESTROYED 0x0400 /* name association is considered destroyed */ 164 #define NCF_DEFEREDZAP 0x0800 /* zap defered due to lock unavailability */ 165 166 #define NC_EXLOCK_REQ 0x80000000 /* ex_lock state */ 167 168 /* 169 * cache_inval[_vp]() flags 170 */ 171 #define CINV_DESTROY 0x0001 /* flag so cache_nlookup ignores the ncp */ 172 #define CINV_UNUSED02 0x0002 173 #define CINV_CHILDREN 0x0004 /* recursively set children to unresolved */ 174 175 /* 176 * MP lock helper for namecache. 177 * 178 * CACHE_GETMPLOCK1() Conditionally gets the MP lock if cache_mpsafe 179 * is not set, otherwise does not. 180 * 181 * CACHE_GETMPLOCK2() Unconditionally gets the MP lock if it is not already 182 * held (e.g. from GETMPLOCK1). 183 * 184 * CACHE_RELMPLOCK() Releases the MP lock if it was previously acquired 185 * by GETMPLOCK1 or GETMPLOCK2. 186 */ 187 #define CACHE_MPLOCK_DECLARE int have_mplock 188 189 #define CACHE_GETMPLOCK1() \ 190 do { \ 191 if (cache_mpsafe) { \ 192 have_mplock = 0; \ 193 } else { \ 194 get_mplock(); \ 195 have_mplock = 1; \ 196 } \ 197 } while (0) 198 199 #define CACHE_GETMPLOCK2() \ 200 do { \ 201 if (have_mplock == 0) { \ 202 have_mplock = 1; \ 203 get_mplock(); \ 204 } \ 205 } while(0) 206 207 #define CACHE_RELMPLOCK() \ 208 do { \ 209 if (have_mplock) { \ 210 have_mplock = 0; \ 211 rel_mplock(); \ 212 } \ 213 } while(0) 214 215 #ifdef _KERNEL 216 217 extern int cache_mpsafe; 218 219 struct componentname; 220 struct nlcomponent; 221 struct mount; 222 223 void cache_lock(struct nchandle *nch); 224 void cache_relock(struct nchandle *nch1, struct ucred *cred1, 225 struct nchandle *nch2, struct ucred *cred2); 226 int cache_lock_nonblock(struct nchandle *nch); 227 void cache_unlock(struct nchandle *nch); 228 void cache_setvp(struct nchandle *nch, struct vnode *vp); 229 void cache_settimeout(struct nchandle *nch, int nticks); 230 void cache_setunresolved(struct nchandle *nch); 231 void cache_clrmountpt(struct nchandle *nch); 232 struct nchandle cache_nlookup(struct nchandle *nch, struct nlcomponent *nlc); 233 struct nchandle cache_nlookup_nonblock(struct nchandle *nch, 234 struct nlcomponent *nlc); 235 void cache_allocroot(struct nchandle *nch, struct mount *mp, struct vnode *vp); 236 struct mount *cache_findmount(struct nchandle *nch); 237 int cache_inval(struct nchandle *nch, int flags); 238 int cache_inval_vp(struct vnode *vp, int flags); 239 int cache_inval_vp_nonblock(struct vnode *vp); 240 void vfs_cache_setroot(struct vnode *vp, struct nchandle *nch); 241 242 int cache_resolve(struct nchandle *nch, struct ucred *cred); 243 void cache_purge(struct vnode *vp); 244 void cache_purgevfs (struct mount *mp); 245 int cache_get_nonblock(struct nchandle *nch, struct nchandle *target); 246 void cache_hysteresis(void); 247 void cache_get(struct nchandle *nch, struct nchandle *target); 248 struct nchandle *cache_hold(struct nchandle *nch); 249 void cache_copy(struct nchandle *nch, struct nchandle *target); 250 void cache_changemount(struct nchandle *nch, struct mount *mp); 251 void cache_put(struct nchandle *nch); 252 void cache_drop(struct nchandle *nch); 253 void cache_zero(struct nchandle *nch); 254 void cache_rename(struct nchandle *fnch, struct nchandle *tnch); 255 int cache_vget(struct nchandle *, struct ucred *, int, struct vnode **); 256 int cache_vref(struct nchandle *, struct ucred *, struct vnode **); 257 int cache_fromdvp(struct vnode *, struct ucred *, int, struct nchandle *); 258 int cache_fullpath(struct proc *, struct nchandle *, char **, char **, int); 259 260 #endif 261 262 #endif 263