1 /*- 2 * Copyright (c) 1989, 1993, 1995 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Poul-Henning Kamp of the FreeBSD Project. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 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 the 15 * documentation and/or other materials provided with the distribution. 16 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)vfs_cache.c 8.5 (Berkeley) 3/22/95 33 */ 34 35 #include <sys/cdefs.h> 36 __FBSDID("$FreeBSD$"); 37 38 #include "opt_ktrace.h" 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/filedesc.h> 43 #include <sys/fnv_hash.h> 44 #include <sys/kernel.h> 45 #include <sys/lock.h> 46 #include <sys/malloc.h> 47 #include <sys/fcntl.h> 48 #include <sys/mount.h> 49 #include <sys/namei.h> 50 #include <sys/proc.h> 51 #include <sys/rwlock.h> 52 #include <sys/sdt.h> 53 #include <sys/syscallsubr.h> 54 #include <sys/sysctl.h> 55 #include <sys/sysproto.h> 56 #include <sys/vnode.h> 57 #ifdef KTRACE 58 #include <sys/ktrace.h> 59 #endif 60 61 #include <vm/uma.h> 62 63 SDT_PROVIDER_DECLARE(vfs); 64 SDT_PROBE_DEFINE3(vfs, namecache, enter, done, "struct vnode *", "char *", 65 "struct vnode *"); 66 SDT_PROBE_DEFINE2(vfs, namecache, enter_negative, done, "struct vnode *", 67 "char *"); 68 SDT_PROBE_DEFINE1(vfs, namecache, fullpath, entry, "struct vnode *"); 69 SDT_PROBE_DEFINE3(vfs, namecache, fullpath, hit, "struct vnode *", 70 "char *", "struct vnode *"); 71 SDT_PROBE_DEFINE1(vfs, namecache, fullpath, miss, "struct vnode *"); 72 SDT_PROBE_DEFINE3(vfs, namecache, fullpath, return, "int", 73 "struct vnode *", "char *"); 74 SDT_PROBE_DEFINE3(vfs, namecache, lookup, hit, "struct vnode *", "char *", 75 "struct vnode *"); 76 SDT_PROBE_DEFINE2(vfs, namecache, lookup, hit__negative, 77 "struct vnode *", "char *"); 78 SDT_PROBE_DEFINE2(vfs, namecache, lookup, miss, "struct vnode *", 79 "char *"); 80 SDT_PROBE_DEFINE1(vfs, namecache, purge, done, "struct vnode *"); 81 SDT_PROBE_DEFINE1(vfs, namecache, purge_negative, done, "struct vnode *"); 82 SDT_PROBE_DEFINE1(vfs, namecache, purgevfs, done, "struct mount *"); 83 SDT_PROBE_DEFINE3(vfs, namecache, zap, done, "struct vnode *", "char *", 84 "struct vnode *"); 85 SDT_PROBE_DEFINE2(vfs, namecache, zap_negative, done, "struct vnode *", 86 "char *"); 87 88 /* 89 * This structure describes the elements in the cache of recent 90 * names looked up by namei. 91 */ 92 93 struct namecache { 94 LIST_ENTRY(namecache) nc_hash; /* hash chain */ 95 LIST_ENTRY(namecache) nc_src; /* source vnode list */ 96 TAILQ_ENTRY(namecache) nc_dst; /* destination vnode list */ 97 struct vnode *nc_dvp; /* vnode of parent of name */ 98 struct vnode *nc_vp; /* vnode the name refers to */ 99 u_char nc_flag; /* flag bits */ 100 u_char nc_nlen; /* length of name */ 101 char nc_name[0]; /* segment name + nul */ 102 }; 103 104 /* 105 * struct namecache_ts repeats struct namecache layout up to the 106 * nc_nlen member. 107 * struct namecache_ts is used in place of struct namecache when time(s) need 108 * to be stored. The nc_dotdottime field is used when a cache entry is mapping 109 * both a non-dotdot directory name plus dotdot for the directory's 110 * parent. 111 */ 112 struct namecache_ts { 113 LIST_ENTRY(namecache) nc_hash; /* hash chain */ 114 LIST_ENTRY(namecache) nc_src; /* source vnode list */ 115 TAILQ_ENTRY(namecache) nc_dst; /* destination vnode list */ 116 struct vnode *nc_dvp; /* vnode of parent of name */ 117 struct vnode *nc_vp; /* vnode the name refers to */ 118 u_char nc_flag; /* flag bits */ 119 u_char nc_nlen; /* length of name */ 120 struct timespec nc_time; /* timespec provided by fs */ 121 struct timespec nc_dotdottime; /* dotdot timespec provided by fs */ 122 int nc_ticks; /* ticks value when entry was added */ 123 char nc_name[0]; /* segment name + nul */ 124 }; 125 126 /* 127 * Flags in namecache.nc_flag 128 */ 129 #define NCF_WHITE 0x01 130 #define NCF_ISDOTDOT 0x02 131 #define NCF_TS 0x04 132 #define NCF_DTS 0x08 133 134 /* 135 * Name caching works as follows: 136 * 137 * Names found by directory scans are retained in a cache 138 * for future reference. It is managed LRU, so frequently 139 * used names will hang around. Cache is indexed by hash value 140 * obtained from (vp, name) where vp refers to the directory 141 * containing name. 142 * 143 * If it is a "negative" entry, (i.e. for a name that is known NOT to 144 * exist) the vnode pointer will be NULL. 145 * 146 * Upon reaching the last segment of a path, if the reference 147 * is for DELETE, or NOCACHE is set (rewrite), and the 148 * name is located in the cache, it will be dropped. 149 */ 150 151 /* 152 * Structures associated with name cacheing. 153 */ 154 #define NCHHASH(hash) \ 155 (&nchashtbl[(hash) & nchash]) 156 static LIST_HEAD(nchashhead, namecache) *nchashtbl; /* Hash Table */ 157 static TAILQ_HEAD(, namecache) ncneg; /* Hash Table */ 158 static u_long nchash; /* size of hash table */ 159 SYSCTL_ULONG(_debug, OID_AUTO, nchash, CTLFLAG_RD, &nchash, 0, 160 "Size of namecache hash table"); 161 static u_long ncnegfactor = 16; /* ratio of negative entries */ 162 SYSCTL_ULONG(_vfs, OID_AUTO, ncnegfactor, CTLFLAG_RW, &ncnegfactor, 0, 163 "Ratio of negative namecache entries"); 164 static u_long numneg; /* number of negative entries allocated */ 165 SYSCTL_ULONG(_debug, OID_AUTO, numneg, CTLFLAG_RD, &numneg, 0, 166 "Number of negative entries in namecache"); 167 static u_long numcache; /* number of cache entries allocated */ 168 SYSCTL_ULONG(_debug, OID_AUTO, numcache, CTLFLAG_RD, &numcache, 0, 169 "Number of namecache entries"); 170 static u_long numcachehv; /* number of cache entries with vnodes held */ 171 SYSCTL_ULONG(_debug, OID_AUTO, numcachehv, CTLFLAG_RD, &numcachehv, 0, 172 "Number of namecache entries with vnodes held"); 173 static u_int ncsizefactor = 2; 174 SYSCTL_UINT(_vfs, OID_AUTO, ncsizefactor, CTLFLAG_RW, &ncsizefactor, 0, 175 "Size factor for namecache"); 176 177 struct nchstats nchstats; /* cache effectiveness statistics */ 178 179 static struct rwlock cache_lock; 180 RW_SYSINIT(vfscache, &cache_lock, "Name Cache"); 181 182 #define CACHE_UPGRADE_LOCK() rw_try_upgrade(&cache_lock) 183 #define CACHE_RLOCK() rw_rlock(&cache_lock) 184 #define CACHE_RUNLOCK() rw_runlock(&cache_lock) 185 #define CACHE_WLOCK() rw_wlock(&cache_lock) 186 #define CACHE_WUNLOCK() rw_wunlock(&cache_lock) 187 188 /* 189 * UMA zones for the VFS cache. 190 * 191 * The small cache is used for entries with short names, which are the 192 * most common. The large cache is used for entries which are too big to 193 * fit in the small cache. 194 */ 195 static uma_zone_t cache_zone_small; 196 static uma_zone_t cache_zone_small_ts; 197 static uma_zone_t cache_zone_large; 198 static uma_zone_t cache_zone_large_ts; 199 200 #define CACHE_PATH_CUTOFF 35 201 202 static struct namecache * 203 cache_alloc(int len, int ts) 204 { 205 206 if (len > CACHE_PATH_CUTOFF) { 207 if (ts) 208 return (uma_zalloc(cache_zone_large_ts, M_WAITOK)); 209 else 210 return (uma_zalloc(cache_zone_large, M_WAITOK)); 211 } 212 if (ts) 213 return (uma_zalloc(cache_zone_small_ts, M_WAITOK)); 214 else 215 return (uma_zalloc(cache_zone_small, M_WAITOK)); 216 } 217 218 static void 219 cache_free(struct namecache *ncp) 220 { 221 int ts; 222 223 if (ncp == NULL) 224 return; 225 ts = ncp->nc_flag & NCF_TS; 226 if (ncp->nc_nlen <= CACHE_PATH_CUTOFF) { 227 if (ts) 228 uma_zfree(cache_zone_small_ts, ncp); 229 else 230 uma_zfree(cache_zone_small, ncp); 231 } else if (ts) 232 uma_zfree(cache_zone_large_ts, ncp); 233 else 234 uma_zfree(cache_zone_large, ncp); 235 } 236 237 static char * 238 nc_get_name(struct namecache *ncp) 239 { 240 struct namecache_ts *ncp_ts; 241 242 if ((ncp->nc_flag & NCF_TS) == 0) 243 return (ncp->nc_name); 244 ncp_ts = (struct namecache_ts *)ncp; 245 return (ncp_ts->nc_name); 246 } 247 248 static void 249 cache_out_ts(struct namecache *ncp, struct timespec *tsp, int *ticksp) 250 { 251 252 KASSERT((ncp->nc_flag & NCF_TS) != 0 || 253 (tsp == NULL && ticksp == NULL), 254 ("No NCF_TS")); 255 256 if (tsp != NULL) 257 *tsp = ((struct namecache_ts *)ncp)->nc_time; 258 if (ticksp != NULL) 259 *ticksp = ((struct namecache_ts *)ncp)->nc_ticks; 260 } 261 262 static int doingcache = 1; /* 1 => enable the cache */ 263 SYSCTL_INT(_debug, OID_AUTO, vfscache, CTLFLAG_RW, &doingcache, 0, 264 "VFS namecache enabled"); 265 266 /* Export size information to userland */ 267 SYSCTL_INT(_debug_sizeof, OID_AUTO, namecache, CTLFLAG_RD, SYSCTL_NULL_INT_PTR, 268 sizeof(struct namecache), "sizeof(struct namecache)"); 269 270 /* 271 * The new name cache statistics 272 */ 273 static SYSCTL_NODE(_vfs, OID_AUTO, cache, CTLFLAG_RW, 0, 274 "Name cache statistics"); 275 #define STATNODE(mode, name, var, descr) \ 276 SYSCTL_ULONG(_vfs_cache, OID_AUTO, name, mode, var, 0, descr); 277 STATNODE(CTLFLAG_RD, numneg, &numneg, "Number of negative cache entries"); 278 STATNODE(CTLFLAG_RD, numcache, &numcache, "Number of cache entries"); 279 static u_long numcalls; STATNODE(CTLFLAG_RD, numcalls, &numcalls, 280 "Number of cache lookups"); 281 static u_long dothits; STATNODE(CTLFLAG_RD, dothits, &dothits, 282 "Number of '.' hits"); 283 static u_long dotdothits; STATNODE(CTLFLAG_RD, dotdothits, &dotdothits, 284 "Number of '..' hits"); 285 static u_long numchecks; STATNODE(CTLFLAG_RD, numchecks, &numchecks, 286 "Number of checks in lookup"); 287 static u_long nummiss; STATNODE(CTLFLAG_RD, nummiss, &nummiss, 288 "Number of cache misses"); 289 static u_long nummisszap; STATNODE(CTLFLAG_RD, nummisszap, &nummisszap, 290 "Number of cache misses we do not want to cache"); 291 static u_long numposzaps; STATNODE(CTLFLAG_RD, numposzaps, &numposzaps, 292 "Number of cache hits (positive) we do not want to cache"); 293 static u_long numposhits; STATNODE(CTLFLAG_RD, numposhits, &numposhits, 294 "Number of cache hits (positive)"); 295 static u_long numnegzaps; STATNODE(CTLFLAG_RD, numnegzaps, &numnegzaps, 296 "Number of cache hits (negative) we do not want to cache"); 297 static u_long numneghits; STATNODE(CTLFLAG_RD, numneghits, &numneghits, 298 "Number of cache hits (negative)"); 299 static u_long numupgrades; STATNODE(CTLFLAG_RD, numupgrades, &numupgrades, 300 "Number of updates of the cache after lookup (write lock + retry)"); 301 302 SYSCTL_OPAQUE(_vfs_cache, OID_AUTO, nchstats, CTLFLAG_RD | CTLFLAG_MPSAFE, 303 &nchstats, sizeof(nchstats), "LU", 304 "VFS cache effectiveness statistics"); 305 306 307 308 static void cache_zap(struct namecache *ncp); 309 static int vn_vptocnp_locked(struct vnode **vp, struct ucred *cred, char *buf, 310 u_int *buflen); 311 static int vn_fullpath1(struct thread *td, struct vnode *vp, struct vnode *rdir, 312 char *buf, char **retbuf, u_int buflen); 313 314 static MALLOC_DEFINE(M_VFSCACHE, "vfscache", "VFS name cache entries"); 315 316 #ifdef DIAGNOSTIC 317 /* 318 * Grab an atomic snapshot of the name cache hash chain lengths 319 */ 320 static SYSCTL_NODE(_debug, OID_AUTO, hashstat, CTLFLAG_RW, NULL, 321 "hash table stats"); 322 323 static int 324 sysctl_debug_hashstat_rawnchash(SYSCTL_HANDLER_ARGS) 325 { 326 struct nchashhead *ncpp; 327 struct namecache *ncp; 328 int i, error, n_nchash, *cntbuf; 329 330 retry: 331 n_nchash = nchash + 1; /* nchash is max index, not count */ 332 if (req->oldptr == NULL) 333 return SYSCTL_OUT(req, 0, n_nchash * sizeof(int)); 334 cntbuf = malloc(n_nchash * sizeof(int), M_TEMP, M_ZERO | M_WAITOK); 335 CACHE_RLOCK(); 336 if (n_nchash != nchash + 1) { 337 CACHE_RUNLOCK(); 338 free(cntbuf, M_TEMP); 339 goto retry; 340 } 341 /* Scan hash tables counting entries */ 342 for (ncpp = nchashtbl, i = 0; i < n_nchash; ncpp++, i++) 343 LIST_FOREACH(ncp, ncpp, nc_hash) 344 cntbuf[i]++; 345 CACHE_RUNLOCK(); 346 for (error = 0, i = 0; i < n_nchash; i++) 347 if ((error = SYSCTL_OUT(req, &cntbuf[i], sizeof(int))) != 0) 348 break; 349 free(cntbuf, M_TEMP); 350 return (error); 351 } 352 SYSCTL_PROC(_debug_hashstat, OID_AUTO, rawnchash, CTLTYPE_INT|CTLFLAG_RD| 353 CTLFLAG_MPSAFE, 0, 0, sysctl_debug_hashstat_rawnchash, "S,int", 354 "nchash chain lengths"); 355 356 static int 357 sysctl_debug_hashstat_nchash(SYSCTL_HANDLER_ARGS) 358 { 359 int error; 360 struct nchashhead *ncpp; 361 struct namecache *ncp; 362 int n_nchash; 363 int count, maxlength, used, pct; 364 365 if (!req->oldptr) 366 return SYSCTL_OUT(req, 0, 4 * sizeof(int)); 367 368 CACHE_RLOCK(); 369 n_nchash = nchash + 1; /* nchash is max index, not count */ 370 used = 0; 371 maxlength = 0; 372 373 /* Scan hash tables for applicable entries */ 374 for (ncpp = nchashtbl; n_nchash > 0; n_nchash--, ncpp++) { 375 count = 0; 376 LIST_FOREACH(ncp, ncpp, nc_hash) { 377 count++; 378 } 379 if (count) 380 used++; 381 if (maxlength < count) 382 maxlength = count; 383 } 384 n_nchash = nchash + 1; 385 CACHE_RUNLOCK(); 386 pct = (used * 100) / (n_nchash / 100); 387 error = SYSCTL_OUT(req, &n_nchash, sizeof(n_nchash)); 388 if (error) 389 return (error); 390 error = SYSCTL_OUT(req, &used, sizeof(used)); 391 if (error) 392 return (error); 393 error = SYSCTL_OUT(req, &maxlength, sizeof(maxlength)); 394 if (error) 395 return (error); 396 error = SYSCTL_OUT(req, &pct, sizeof(pct)); 397 if (error) 398 return (error); 399 return (0); 400 } 401 SYSCTL_PROC(_debug_hashstat, OID_AUTO, nchash, CTLTYPE_INT|CTLFLAG_RD| 402 CTLFLAG_MPSAFE, 0, 0, sysctl_debug_hashstat_nchash, "I", 403 "nchash statistics (number of total/used buckets, maximum chain length, usage percentage)"); 404 #endif 405 406 /* 407 * cache_zap(): 408 * 409 * Removes a namecache entry from cache, whether it contains an actual 410 * pointer to a vnode or if it is just a negative cache entry. 411 */ 412 static void 413 cache_zap(ncp) 414 struct namecache *ncp; 415 { 416 struct vnode *vp; 417 418 rw_assert(&cache_lock, RA_WLOCKED); 419 CTR2(KTR_VFS, "cache_zap(%p) vp %p", ncp, ncp->nc_vp); 420 if (ncp->nc_vp != NULL) { 421 SDT_PROBE3(vfs, namecache, zap, done, ncp->nc_dvp, 422 nc_get_name(ncp), ncp->nc_vp); 423 } else { 424 SDT_PROBE2(vfs, namecache, zap_negative, done, ncp->nc_dvp, 425 nc_get_name(ncp)); 426 } 427 vp = NULL; 428 LIST_REMOVE(ncp, nc_hash); 429 if (ncp->nc_flag & NCF_ISDOTDOT) { 430 if (ncp == ncp->nc_dvp->v_cache_dd) 431 ncp->nc_dvp->v_cache_dd = NULL; 432 } else { 433 LIST_REMOVE(ncp, nc_src); 434 if (LIST_EMPTY(&ncp->nc_dvp->v_cache_src)) { 435 vp = ncp->nc_dvp; 436 numcachehv--; 437 } 438 } 439 if (ncp->nc_vp) { 440 TAILQ_REMOVE(&ncp->nc_vp->v_cache_dst, ncp, nc_dst); 441 if (ncp == ncp->nc_vp->v_cache_dd) 442 ncp->nc_vp->v_cache_dd = NULL; 443 } else { 444 TAILQ_REMOVE(&ncneg, ncp, nc_dst); 445 numneg--; 446 } 447 numcache--; 448 cache_free(ncp); 449 if (vp) 450 vdrop(vp); 451 } 452 453 /* 454 * Lookup an entry in the cache 455 * 456 * Lookup is called with dvp pointing to the directory to search, 457 * cnp pointing to the name of the entry being sought. If the lookup 458 * succeeds, the vnode is returned in *vpp, and a status of -1 is 459 * returned. If the lookup determines that the name does not exist 460 * (negative cacheing), a status of ENOENT is returned. If the lookup 461 * fails, a status of zero is returned. If the directory vnode is 462 * recycled out from under us due to a forced unmount, a status of 463 * ENOENT is returned. 464 * 465 * vpp is locked and ref'd on return. If we're looking up DOTDOT, dvp is 466 * unlocked. If we're looking up . an extra ref is taken, but the lock is 467 * not recursively acquired. 468 */ 469 470 int 471 cache_lookup(dvp, vpp, cnp, tsp, ticksp) 472 struct vnode *dvp; 473 struct vnode **vpp; 474 struct componentname *cnp; 475 struct timespec *tsp; 476 int *ticksp; 477 { 478 struct namecache *ncp; 479 uint32_t hash; 480 int error, ltype, wlocked; 481 482 if (!doingcache) { 483 cnp->cn_flags &= ~MAKEENTRY; 484 return (0); 485 } 486 retry: 487 CACHE_RLOCK(); 488 wlocked = 0; 489 numcalls++; 490 error = 0; 491 492 retry_wlocked: 493 if (cnp->cn_nameptr[0] == '.') { 494 if (cnp->cn_namelen == 1) { 495 *vpp = dvp; 496 CTR2(KTR_VFS, "cache_lookup(%p, %s) found via .", 497 dvp, cnp->cn_nameptr); 498 dothits++; 499 SDT_PROBE3(vfs, namecache, lookup, hit, dvp, ".", *vpp); 500 if (tsp != NULL) 501 timespecclear(tsp); 502 if (ticksp != NULL) 503 *ticksp = ticks; 504 goto success; 505 } 506 if (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.') { 507 dotdothits++; 508 if (dvp->v_cache_dd == NULL) { 509 SDT_PROBE3(vfs, namecache, lookup, miss, dvp, 510 "..", NULL); 511 goto unlock; 512 } 513 if ((cnp->cn_flags & MAKEENTRY) == 0) { 514 if (!wlocked && !CACHE_UPGRADE_LOCK()) 515 goto wlock; 516 if (dvp->v_cache_dd->nc_flag & NCF_ISDOTDOT) 517 cache_zap(dvp->v_cache_dd); 518 dvp->v_cache_dd = NULL; 519 CACHE_WUNLOCK(); 520 return (0); 521 } 522 ncp = dvp->v_cache_dd; 523 if (ncp->nc_flag & NCF_ISDOTDOT) 524 *vpp = ncp->nc_vp; 525 else 526 *vpp = ncp->nc_dvp; 527 /* Return failure if negative entry was found. */ 528 if (*vpp == NULL) 529 goto negative_success; 530 CTR3(KTR_VFS, "cache_lookup(%p, %s) found %p via ..", 531 dvp, cnp->cn_nameptr, *vpp); 532 SDT_PROBE3(vfs, namecache, lookup, hit, dvp, "..", 533 *vpp); 534 cache_out_ts(ncp, tsp, ticksp); 535 if ((ncp->nc_flag & (NCF_ISDOTDOT | NCF_DTS)) == 536 NCF_DTS && tsp != NULL) 537 *tsp = ((struct namecache_ts *)ncp)-> 538 nc_dotdottime; 539 goto success; 540 } 541 } 542 543 hash = fnv_32_buf(cnp->cn_nameptr, cnp->cn_namelen, FNV1_32_INIT); 544 hash = fnv_32_buf(&dvp, sizeof(dvp), hash); 545 LIST_FOREACH(ncp, (NCHHASH(hash)), nc_hash) { 546 numchecks++; 547 if (ncp->nc_dvp == dvp && ncp->nc_nlen == cnp->cn_namelen && 548 !bcmp(nc_get_name(ncp), cnp->cn_nameptr, ncp->nc_nlen)) 549 break; 550 } 551 552 /* We failed to find an entry */ 553 if (ncp == NULL) { 554 SDT_PROBE3(vfs, namecache, lookup, miss, dvp, cnp->cn_nameptr, 555 NULL); 556 if ((cnp->cn_flags & MAKEENTRY) == 0) { 557 nummisszap++; 558 } else { 559 nummiss++; 560 } 561 nchstats.ncs_miss++; 562 goto unlock; 563 } 564 565 /* We don't want to have an entry, so dump it */ 566 if ((cnp->cn_flags & MAKEENTRY) == 0) { 567 numposzaps++; 568 nchstats.ncs_badhits++; 569 if (!wlocked && !CACHE_UPGRADE_LOCK()) 570 goto wlock; 571 cache_zap(ncp); 572 CACHE_WUNLOCK(); 573 return (0); 574 } 575 576 /* We found a "positive" match, return the vnode */ 577 if (ncp->nc_vp) { 578 numposhits++; 579 nchstats.ncs_goodhits++; 580 *vpp = ncp->nc_vp; 581 CTR4(KTR_VFS, "cache_lookup(%p, %s) found %p via ncp %p", 582 dvp, cnp->cn_nameptr, *vpp, ncp); 583 SDT_PROBE3(vfs, namecache, lookup, hit, dvp, nc_get_name(ncp), 584 *vpp); 585 cache_out_ts(ncp, tsp, ticksp); 586 goto success; 587 } 588 589 negative_success: 590 /* We found a negative match, and want to create it, so purge */ 591 if (cnp->cn_nameiop == CREATE) { 592 numnegzaps++; 593 nchstats.ncs_badhits++; 594 if (!wlocked && !CACHE_UPGRADE_LOCK()) 595 goto wlock; 596 cache_zap(ncp); 597 CACHE_WUNLOCK(); 598 return (0); 599 } 600 601 if (!wlocked && !CACHE_UPGRADE_LOCK()) 602 goto wlock; 603 numneghits++; 604 /* 605 * We found a "negative" match, so we shift it to the end of 606 * the "negative" cache entries queue to satisfy LRU. Also, 607 * check to see if the entry is a whiteout; indicate this to 608 * the componentname, if so. 609 */ 610 TAILQ_REMOVE(&ncneg, ncp, nc_dst); 611 TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst); 612 nchstats.ncs_neghits++; 613 if (ncp->nc_flag & NCF_WHITE) 614 cnp->cn_flags |= ISWHITEOUT; 615 SDT_PROBE2(vfs, namecache, lookup, hit__negative, dvp, 616 nc_get_name(ncp)); 617 cache_out_ts(ncp, tsp, ticksp); 618 CACHE_WUNLOCK(); 619 return (ENOENT); 620 621 wlock: 622 /* 623 * We need to update the cache after our lookup, so upgrade to 624 * a write lock and retry the operation. 625 */ 626 CACHE_RUNLOCK(); 627 CACHE_WLOCK(); 628 numupgrades++; 629 wlocked = 1; 630 goto retry_wlocked; 631 632 success: 633 /* 634 * On success we return a locked and ref'd vnode as per the lookup 635 * protocol. 636 */ 637 if (dvp == *vpp) { /* lookup on "." */ 638 VREF(*vpp); 639 if (wlocked) 640 CACHE_WUNLOCK(); 641 else 642 CACHE_RUNLOCK(); 643 /* 644 * When we lookup "." we still can be asked to lock it 645 * differently... 646 */ 647 ltype = cnp->cn_lkflags & LK_TYPE_MASK; 648 if (ltype != VOP_ISLOCKED(*vpp)) { 649 if (ltype == LK_EXCLUSIVE) { 650 vn_lock(*vpp, LK_UPGRADE | LK_RETRY); 651 if ((*vpp)->v_iflag & VI_DOOMED) { 652 /* forced unmount */ 653 vrele(*vpp); 654 *vpp = NULL; 655 return (ENOENT); 656 } 657 } else 658 vn_lock(*vpp, LK_DOWNGRADE | LK_RETRY); 659 } 660 return (-1); 661 } 662 ltype = 0; /* silence gcc warning */ 663 if (cnp->cn_flags & ISDOTDOT) { 664 ltype = VOP_ISLOCKED(dvp); 665 VOP_UNLOCK(dvp, 0); 666 } 667 vhold(*vpp); 668 if (wlocked) 669 CACHE_WUNLOCK(); 670 else 671 CACHE_RUNLOCK(); 672 error = vget(*vpp, cnp->cn_lkflags | LK_VNHELD, cnp->cn_thread); 673 if (cnp->cn_flags & ISDOTDOT) { 674 vn_lock(dvp, ltype | LK_RETRY); 675 if (dvp->v_iflag & VI_DOOMED) { 676 if (error == 0) 677 vput(*vpp); 678 *vpp = NULL; 679 return (ENOENT); 680 } 681 } 682 if (error) { 683 *vpp = NULL; 684 goto retry; 685 } 686 if ((cnp->cn_flags & ISLASTCN) && 687 (cnp->cn_lkflags & LK_TYPE_MASK) == LK_EXCLUSIVE) { 688 ASSERT_VOP_ELOCKED(*vpp, "cache_lookup"); 689 } 690 return (-1); 691 692 unlock: 693 if (wlocked) 694 CACHE_WUNLOCK(); 695 else 696 CACHE_RUNLOCK(); 697 return (0); 698 } 699 700 /* 701 * Add an entry to the cache. 702 */ 703 void 704 cache_enter_time(dvp, vp, cnp, tsp, dtsp) 705 struct vnode *dvp; 706 struct vnode *vp; 707 struct componentname *cnp; 708 struct timespec *tsp; 709 struct timespec *dtsp; 710 { 711 struct namecache *ncp, *n2; 712 struct namecache_ts *n3; 713 struct nchashhead *ncpp; 714 uint32_t hash; 715 int flag; 716 int hold; 717 int zap; 718 int len; 719 720 CTR3(KTR_VFS, "cache_enter(%p, %p, %s)", dvp, vp, cnp->cn_nameptr); 721 VNASSERT(vp == NULL || (vp->v_iflag & VI_DOOMED) == 0, vp, 722 ("cache_enter: Adding a doomed vnode")); 723 VNASSERT(dvp == NULL || (dvp->v_iflag & VI_DOOMED) == 0, dvp, 724 ("cache_enter: Doomed vnode used as src")); 725 726 if (!doingcache) 727 return; 728 729 /* 730 * Avoid blowout in namecache entries. 731 */ 732 if (numcache >= desiredvnodes * ncsizefactor) 733 return; 734 735 flag = 0; 736 if (cnp->cn_nameptr[0] == '.') { 737 if (cnp->cn_namelen == 1) 738 return; 739 if (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.') { 740 CACHE_WLOCK(); 741 /* 742 * If dotdot entry already exists, just retarget it 743 * to new parent vnode, otherwise continue with new 744 * namecache entry allocation. 745 */ 746 if ((ncp = dvp->v_cache_dd) != NULL && 747 ncp->nc_flag & NCF_ISDOTDOT) { 748 KASSERT(ncp->nc_dvp == dvp, 749 ("wrong isdotdot parent")); 750 if (ncp->nc_vp != NULL) { 751 TAILQ_REMOVE(&ncp->nc_vp->v_cache_dst, 752 ncp, nc_dst); 753 } else { 754 TAILQ_REMOVE(&ncneg, ncp, nc_dst); 755 numneg--; 756 } 757 if (vp != NULL) { 758 TAILQ_INSERT_HEAD(&vp->v_cache_dst, 759 ncp, nc_dst); 760 } else { 761 TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst); 762 numneg++; 763 } 764 ncp->nc_vp = vp; 765 CACHE_WUNLOCK(); 766 return; 767 } 768 dvp->v_cache_dd = NULL; 769 SDT_PROBE3(vfs, namecache, enter, done, dvp, "..", vp); 770 CACHE_WUNLOCK(); 771 flag = NCF_ISDOTDOT; 772 } 773 } 774 775 hold = 0; 776 zap = 0; 777 778 /* 779 * Calculate the hash key and setup as much of the new 780 * namecache entry as possible before acquiring the lock. 781 */ 782 ncp = cache_alloc(cnp->cn_namelen, tsp != NULL); 783 ncp->nc_vp = vp; 784 ncp->nc_dvp = dvp; 785 ncp->nc_flag = flag; 786 if (tsp != NULL) { 787 n3 = (struct namecache_ts *)ncp; 788 n3->nc_time = *tsp; 789 n3->nc_ticks = ticks; 790 n3->nc_flag |= NCF_TS; 791 if (dtsp != NULL) { 792 n3->nc_dotdottime = *dtsp; 793 n3->nc_flag |= NCF_DTS; 794 } 795 } 796 len = ncp->nc_nlen = cnp->cn_namelen; 797 hash = fnv_32_buf(cnp->cn_nameptr, len, FNV1_32_INIT); 798 strlcpy(nc_get_name(ncp), cnp->cn_nameptr, len + 1); 799 hash = fnv_32_buf(&dvp, sizeof(dvp), hash); 800 CACHE_WLOCK(); 801 802 /* 803 * See if this vnode or negative entry is already in the cache 804 * with this name. This can happen with concurrent lookups of 805 * the same path name. 806 */ 807 ncpp = NCHHASH(hash); 808 LIST_FOREACH(n2, ncpp, nc_hash) { 809 if (n2->nc_dvp == dvp && 810 n2->nc_nlen == cnp->cn_namelen && 811 !bcmp(nc_get_name(n2), cnp->cn_nameptr, n2->nc_nlen)) { 812 if (tsp != NULL) { 813 KASSERT((n2->nc_flag & NCF_TS) != 0, 814 ("no NCF_TS")); 815 n3 = (struct namecache_ts *)n2; 816 n3->nc_time = 817 ((struct namecache_ts *)ncp)->nc_time; 818 n3->nc_ticks = 819 ((struct namecache_ts *)ncp)->nc_ticks; 820 if (dtsp != NULL) { 821 n3->nc_dotdottime = 822 ((struct namecache_ts *)ncp)-> 823 nc_dotdottime; 824 n3->nc_flag |= NCF_DTS; 825 } 826 } 827 CACHE_WUNLOCK(); 828 cache_free(ncp); 829 return; 830 } 831 } 832 833 if (flag == NCF_ISDOTDOT) { 834 /* 835 * See if we are trying to add .. entry, but some other lookup 836 * has populated v_cache_dd pointer already. 837 */ 838 if (dvp->v_cache_dd != NULL) { 839 CACHE_WUNLOCK(); 840 cache_free(ncp); 841 return; 842 } 843 KASSERT(vp == NULL || vp->v_type == VDIR, 844 ("wrong vnode type %p", vp)); 845 dvp->v_cache_dd = ncp; 846 } 847 848 numcache++; 849 if (!vp) { 850 numneg++; 851 if (cnp->cn_flags & ISWHITEOUT) 852 ncp->nc_flag |= NCF_WHITE; 853 } else if (vp->v_type == VDIR) { 854 if (flag != NCF_ISDOTDOT) { 855 /* 856 * For this case, the cache entry maps both the 857 * directory name in it and the name ".." for the 858 * directory's parent. 859 */ 860 if ((n2 = vp->v_cache_dd) != NULL && 861 (n2->nc_flag & NCF_ISDOTDOT) != 0) 862 cache_zap(n2); 863 vp->v_cache_dd = ncp; 864 } 865 } else { 866 vp->v_cache_dd = NULL; 867 } 868 869 /* 870 * Insert the new namecache entry into the appropriate chain 871 * within the cache entries table. 872 */ 873 LIST_INSERT_HEAD(ncpp, ncp, nc_hash); 874 if (flag != NCF_ISDOTDOT) { 875 if (LIST_EMPTY(&dvp->v_cache_src)) { 876 hold = 1; 877 numcachehv++; 878 } 879 LIST_INSERT_HEAD(&dvp->v_cache_src, ncp, nc_src); 880 } 881 882 /* 883 * If the entry is "negative", we place it into the 884 * "negative" cache queue, otherwise, we place it into the 885 * destination vnode's cache entries queue. 886 */ 887 if (vp) { 888 TAILQ_INSERT_HEAD(&vp->v_cache_dst, ncp, nc_dst); 889 SDT_PROBE3(vfs, namecache, enter, done, dvp, nc_get_name(ncp), 890 vp); 891 } else { 892 TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst); 893 SDT_PROBE2(vfs, namecache, enter_negative, done, dvp, 894 nc_get_name(ncp)); 895 } 896 if (numneg * ncnegfactor > numcache) { 897 ncp = TAILQ_FIRST(&ncneg); 898 KASSERT(ncp->nc_vp == NULL, ("ncp %p vp %p on ncneg", 899 ncp, ncp->nc_vp)); 900 zap = 1; 901 } 902 if (hold) 903 vhold(dvp); 904 if (zap) 905 cache_zap(ncp); 906 CACHE_WUNLOCK(); 907 } 908 909 /* 910 * Name cache initialization, from vfs_init() when we are booting 911 */ 912 static void 913 nchinit(void *dummy __unused) 914 { 915 916 TAILQ_INIT(&ncneg); 917 918 cache_zone_small = uma_zcreate("S VFS Cache", 919 sizeof(struct namecache) + CACHE_PATH_CUTOFF + 1, 920 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_ZINIT); 921 cache_zone_small_ts = uma_zcreate("STS VFS Cache", 922 sizeof(struct namecache_ts) + CACHE_PATH_CUTOFF + 1, 923 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_ZINIT); 924 cache_zone_large = uma_zcreate("L VFS Cache", 925 sizeof(struct namecache) + NAME_MAX + 1, 926 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_ZINIT); 927 cache_zone_large_ts = uma_zcreate("LTS VFS Cache", 928 sizeof(struct namecache_ts) + NAME_MAX + 1, 929 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_ZINIT); 930 931 nchashtbl = hashinit(desiredvnodes * 2, M_VFSCACHE, &nchash); 932 } 933 SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_SECOND, nchinit, NULL); 934 935 void 936 cache_changesize(int newmaxvnodes) 937 { 938 struct nchashhead *new_nchashtbl, *old_nchashtbl; 939 u_long new_nchash, old_nchash; 940 struct namecache *ncp; 941 uint32_t hash; 942 int i; 943 944 new_nchashtbl = hashinit(newmaxvnodes * 2, M_VFSCACHE, &new_nchash); 945 /* If same hash table size, nothing to do */ 946 if (nchash == new_nchash) { 947 free(new_nchashtbl, M_VFSCACHE); 948 return; 949 } 950 /* 951 * Move everything from the old hash table to the new table. 952 * None of the namecache entries in the table can be removed 953 * because to do so, they have to be removed from the hash table. 954 */ 955 CACHE_WLOCK(); 956 old_nchashtbl = nchashtbl; 957 old_nchash = nchash; 958 nchashtbl = new_nchashtbl; 959 nchash = new_nchash; 960 for (i = 0; i <= old_nchash; i++) { 961 while ((ncp = LIST_FIRST(&old_nchashtbl[i])) != NULL) { 962 hash = fnv_32_buf(nc_get_name(ncp), ncp->nc_nlen, 963 FNV1_32_INIT); 964 hash = fnv_32_buf(&ncp->nc_dvp, sizeof(ncp->nc_dvp), 965 hash); 966 LIST_REMOVE(ncp, nc_hash); 967 LIST_INSERT_HEAD(NCHHASH(hash), ncp, nc_hash); 968 } 969 } 970 CACHE_WUNLOCK(); 971 free(old_nchashtbl, M_VFSCACHE); 972 } 973 974 /* 975 * Invalidate all entries to a particular vnode. 976 */ 977 void 978 cache_purge(vp) 979 struct vnode *vp; 980 { 981 982 CTR1(KTR_VFS, "cache_purge(%p)", vp); 983 SDT_PROBE1(vfs, namecache, purge, done, vp); 984 CACHE_WLOCK(); 985 while (!LIST_EMPTY(&vp->v_cache_src)) 986 cache_zap(LIST_FIRST(&vp->v_cache_src)); 987 while (!TAILQ_EMPTY(&vp->v_cache_dst)) 988 cache_zap(TAILQ_FIRST(&vp->v_cache_dst)); 989 if (vp->v_cache_dd != NULL) { 990 KASSERT(vp->v_cache_dd->nc_flag & NCF_ISDOTDOT, 991 ("lost dotdot link")); 992 cache_zap(vp->v_cache_dd); 993 } 994 KASSERT(vp->v_cache_dd == NULL, ("incomplete purge")); 995 CACHE_WUNLOCK(); 996 } 997 998 /* 999 * Invalidate all negative entries for a particular directory vnode. 1000 */ 1001 void 1002 cache_purge_negative(vp) 1003 struct vnode *vp; 1004 { 1005 struct namecache *cp, *ncp; 1006 1007 CTR1(KTR_VFS, "cache_purge_negative(%p)", vp); 1008 SDT_PROBE1(vfs, namecache, purge_negative, done, vp); 1009 CACHE_WLOCK(); 1010 LIST_FOREACH_SAFE(cp, &vp->v_cache_src, nc_src, ncp) { 1011 if (cp->nc_vp == NULL) 1012 cache_zap(cp); 1013 } 1014 CACHE_WUNLOCK(); 1015 } 1016 1017 /* 1018 * Flush all entries referencing a particular filesystem. 1019 */ 1020 void 1021 cache_purgevfs(mp) 1022 struct mount *mp; 1023 { 1024 struct nchashhead *ncpp; 1025 struct namecache *ncp, *nnp; 1026 1027 /* Scan hash tables for applicable entries */ 1028 SDT_PROBE1(vfs, namecache, purgevfs, done, mp); 1029 CACHE_WLOCK(); 1030 for (ncpp = &nchashtbl[nchash]; ncpp >= nchashtbl; ncpp--) { 1031 LIST_FOREACH_SAFE(ncp, ncpp, nc_hash, nnp) { 1032 if (ncp->nc_dvp->v_mount == mp) 1033 cache_zap(ncp); 1034 } 1035 } 1036 CACHE_WUNLOCK(); 1037 } 1038 1039 /* 1040 * Perform canonical checks and cache lookup and pass on to filesystem 1041 * through the vop_cachedlookup only if needed. 1042 */ 1043 1044 int 1045 vfs_cache_lookup(ap) 1046 struct vop_lookup_args /* { 1047 struct vnode *a_dvp; 1048 struct vnode **a_vpp; 1049 struct componentname *a_cnp; 1050 } */ *ap; 1051 { 1052 struct vnode *dvp; 1053 int error; 1054 struct vnode **vpp = ap->a_vpp; 1055 struct componentname *cnp = ap->a_cnp; 1056 struct ucred *cred = cnp->cn_cred; 1057 int flags = cnp->cn_flags; 1058 struct thread *td = cnp->cn_thread; 1059 1060 *vpp = NULL; 1061 dvp = ap->a_dvp; 1062 1063 if (dvp->v_type != VDIR) 1064 return (ENOTDIR); 1065 1066 if ((flags & ISLASTCN) && (dvp->v_mount->mnt_flag & MNT_RDONLY) && 1067 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) 1068 return (EROFS); 1069 1070 error = VOP_ACCESS(dvp, VEXEC, cred, td); 1071 if (error) 1072 return (error); 1073 1074 error = cache_lookup(dvp, vpp, cnp, NULL, NULL); 1075 if (error == 0) 1076 return (VOP_CACHEDLOOKUP(dvp, vpp, cnp)); 1077 if (error == -1) 1078 return (0); 1079 return (error); 1080 } 1081 1082 /* 1083 * XXX All of these sysctls would probably be more productive dead. 1084 */ 1085 static int disablecwd; 1086 SYSCTL_INT(_debug, OID_AUTO, disablecwd, CTLFLAG_RW, &disablecwd, 0, 1087 "Disable the getcwd syscall"); 1088 1089 /* Implementation of the getcwd syscall. */ 1090 int 1091 sys___getcwd(td, uap) 1092 struct thread *td; 1093 struct __getcwd_args *uap; 1094 { 1095 1096 return (kern___getcwd(td, uap->buf, UIO_USERSPACE, uap->buflen, 1097 MAXPATHLEN)); 1098 } 1099 1100 int 1101 kern___getcwd(struct thread *td, char *buf, enum uio_seg bufseg, u_int buflen, 1102 u_int path_max) 1103 { 1104 char *bp, *tmpbuf; 1105 struct filedesc *fdp; 1106 struct vnode *cdir, *rdir; 1107 int error; 1108 1109 if (disablecwd) 1110 return (ENODEV); 1111 if (buflen < 2) 1112 return (EINVAL); 1113 if (buflen > path_max) 1114 buflen = path_max; 1115 1116 tmpbuf = malloc(buflen, M_TEMP, M_WAITOK); 1117 fdp = td->td_proc->p_fd; 1118 FILEDESC_SLOCK(fdp); 1119 cdir = fdp->fd_cdir; 1120 VREF(cdir); 1121 rdir = fdp->fd_rdir; 1122 VREF(rdir); 1123 FILEDESC_SUNLOCK(fdp); 1124 error = vn_fullpath1(td, cdir, rdir, tmpbuf, &bp, buflen); 1125 vrele(rdir); 1126 vrele(cdir); 1127 1128 if (!error) { 1129 if (bufseg == UIO_SYSSPACE) 1130 bcopy(bp, buf, strlen(bp) + 1); 1131 else 1132 error = copyout(bp, buf, strlen(bp) + 1); 1133 #ifdef KTRACE 1134 if (KTRPOINT(curthread, KTR_NAMEI)) 1135 ktrnamei(bp); 1136 #endif 1137 } 1138 free(tmpbuf, M_TEMP); 1139 return (error); 1140 } 1141 1142 /* 1143 * Thus begins the fullpath magic. 1144 */ 1145 1146 #undef STATNODE 1147 #define STATNODE(name, descr) \ 1148 static u_int name; \ 1149 SYSCTL_UINT(_vfs_cache, OID_AUTO, name, CTLFLAG_RD, &name, 0, descr) 1150 1151 static int disablefullpath; 1152 SYSCTL_INT(_debug, OID_AUTO, disablefullpath, CTLFLAG_RW, &disablefullpath, 0, 1153 "Disable the vn_fullpath function"); 1154 1155 /* These count for kern___getcwd(), too. */ 1156 STATNODE(numfullpathcalls, "Number of fullpath search calls"); 1157 STATNODE(numfullpathfail1, "Number of fullpath search errors (ENOTDIR)"); 1158 STATNODE(numfullpathfail2, 1159 "Number of fullpath search errors (VOP_VPTOCNP failures)"); 1160 STATNODE(numfullpathfail4, "Number of fullpath search errors (ENOMEM)"); 1161 STATNODE(numfullpathfound, "Number of successful fullpath calls"); 1162 1163 /* 1164 * Retrieve the full filesystem path that correspond to a vnode from the name 1165 * cache (if available) 1166 */ 1167 int 1168 vn_fullpath(struct thread *td, struct vnode *vn, char **retbuf, char **freebuf) 1169 { 1170 char *buf; 1171 struct filedesc *fdp; 1172 struct vnode *rdir; 1173 int error; 1174 1175 if (disablefullpath) 1176 return (ENODEV); 1177 if (vn == NULL) 1178 return (EINVAL); 1179 1180 buf = malloc(MAXPATHLEN, M_TEMP, M_WAITOK); 1181 fdp = td->td_proc->p_fd; 1182 FILEDESC_SLOCK(fdp); 1183 rdir = fdp->fd_rdir; 1184 VREF(rdir); 1185 FILEDESC_SUNLOCK(fdp); 1186 error = vn_fullpath1(td, vn, rdir, buf, retbuf, MAXPATHLEN); 1187 vrele(rdir); 1188 1189 if (!error) 1190 *freebuf = buf; 1191 else 1192 free(buf, M_TEMP); 1193 return (error); 1194 } 1195 1196 /* 1197 * This function is similar to vn_fullpath, but it attempts to lookup the 1198 * pathname relative to the global root mount point. This is required for the 1199 * auditing sub-system, as audited pathnames must be absolute, relative to the 1200 * global root mount point. 1201 */ 1202 int 1203 vn_fullpath_global(struct thread *td, struct vnode *vn, 1204 char **retbuf, char **freebuf) 1205 { 1206 char *buf; 1207 int error; 1208 1209 if (disablefullpath) 1210 return (ENODEV); 1211 if (vn == NULL) 1212 return (EINVAL); 1213 buf = malloc(MAXPATHLEN, M_TEMP, M_WAITOK); 1214 error = vn_fullpath1(td, vn, rootvnode, buf, retbuf, MAXPATHLEN); 1215 if (!error) 1216 *freebuf = buf; 1217 else 1218 free(buf, M_TEMP); 1219 return (error); 1220 } 1221 1222 int 1223 vn_vptocnp(struct vnode **vp, struct ucred *cred, char *buf, u_int *buflen) 1224 { 1225 int error; 1226 1227 CACHE_RLOCK(); 1228 error = vn_vptocnp_locked(vp, cred, buf, buflen); 1229 if (error == 0) 1230 CACHE_RUNLOCK(); 1231 return (error); 1232 } 1233 1234 static int 1235 vn_vptocnp_locked(struct vnode **vp, struct ucred *cred, char *buf, 1236 u_int *buflen) 1237 { 1238 struct vnode *dvp; 1239 struct namecache *ncp; 1240 int error; 1241 1242 TAILQ_FOREACH(ncp, &((*vp)->v_cache_dst), nc_dst) { 1243 if ((ncp->nc_flag & NCF_ISDOTDOT) == 0) 1244 break; 1245 } 1246 if (ncp != NULL) { 1247 if (*buflen < ncp->nc_nlen) { 1248 CACHE_RUNLOCK(); 1249 vrele(*vp); 1250 numfullpathfail4++; 1251 error = ENOMEM; 1252 SDT_PROBE3(vfs, namecache, fullpath, return, error, 1253 vp, NULL); 1254 return (error); 1255 } 1256 *buflen -= ncp->nc_nlen; 1257 memcpy(buf + *buflen, nc_get_name(ncp), ncp->nc_nlen); 1258 SDT_PROBE3(vfs, namecache, fullpath, hit, ncp->nc_dvp, 1259 nc_get_name(ncp), vp); 1260 dvp = *vp; 1261 *vp = ncp->nc_dvp; 1262 vref(*vp); 1263 CACHE_RUNLOCK(); 1264 vrele(dvp); 1265 CACHE_RLOCK(); 1266 return (0); 1267 } 1268 SDT_PROBE1(vfs, namecache, fullpath, miss, vp); 1269 1270 CACHE_RUNLOCK(); 1271 vn_lock(*vp, LK_SHARED | LK_RETRY); 1272 error = VOP_VPTOCNP(*vp, &dvp, cred, buf, buflen); 1273 vput(*vp); 1274 if (error) { 1275 numfullpathfail2++; 1276 SDT_PROBE3(vfs, namecache, fullpath, return, error, vp, NULL); 1277 return (error); 1278 } 1279 1280 *vp = dvp; 1281 CACHE_RLOCK(); 1282 if (dvp->v_iflag & VI_DOOMED) { 1283 /* forced unmount */ 1284 CACHE_RUNLOCK(); 1285 vrele(dvp); 1286 error = ENOENT; 1287 SDT_PROBE3(vfs, namecache, fullpath, return, error, vp, NULL); 1288 return (error); 1289 } 1290 /* 1291 * *vp has its use count incremented still. 1292 */ 1293 1294 return (0); 1295 } 1296 1297 /* 1298 * The magic behind kern___getcwd() and vn_fullpath(). 1299 */ 1300 static int 1301 vn_fullpath1(struct thread *td, struct vnode *vp, struct vnode *rdir, 1302 char *buf, char **retbuf, u_int buflen) 1303 { 1304 int error, slash_prefixed; 1305 #ifdef KDTRACE_HOOKS 1306 struct vnode *startvp = vp; 1307 #endif 1308 struct vnode *vp1; 1309 1310 buflen--; 1311 buf[buflen] = '\0'; 1312 error = 0; 1313 slash_prefixed = 0; 1314 1315 SDT_PROBE1(vfs, namecache, fullpath, entry, vp); 1316 numfullpathcalls++; 1317 vref(vp); 1318 CACHE_RLOCK(); 1319 if (vp->v_type != VDIR) { 1320 error = vn_vptocnp_locked(&vp, td->td_ucred, buf, &buflen); 1321 if (error) 1322 return (error); 1323 if (buflen == 0) { 1324 CACHE_RUNLOCK(); 1325 vrele(vp); 1326 return (ENOMEM); 1327 } 1328 buf[--buflen] = '/'; 1329 slash_prefixed = 1; 1330 } 1331 while (vp != rdir && vp != rootvnode) { 1332 if (vp->v_vflag & VV_ROOT) { 1333 if (vp->v_iflag & VI_DOOMED) { /* forced unmount */ 1334 CACHE_RUNLOCK(); 1335 vrele(vp); 1336 error = ENOENT; 1337 SDT_PROBE3(vfs, namecache, fullpath, return, 1338 error, vp, NULL); 1339 break; 1340 } 1341 vp1 = vp->v_mount->mnt_vnodecovered; 1342 vref(vp1); 1343 CACHE_RUNLOCK(); 1344 vrele(vp); 1345 vp = vp1; 1346 CACHE_RLOCK(); 1347 continue; 1348 } 1349 if (vp->v_type != VDIR) { 1350 CACHE_RUNLOCK(); 1351 vrele(vp); 1352 numfullpathfail1++; 1353 error = ENOTDIR; 1354 SDT_PROBE3(vfs, namecache, fullpath, return, 1355 error, vp, NULL); 1356 break; 1357 } 1358 error = vn_vptocnp_locked(&vp, td->td_ucred, buf, &buflen); 1359 if (error) 1360 break; 1361 if (buflen == 0) { 1362 CACHE_RUNLOCK(); 1363 vrele(vp); 1364 error = ENOMEM; 1365 SDT_PROBE3(vfs, namecache, fullpath, return, error, 1366 startvp, NULL); 1367 break; 1368 } 1369 buf[--buflen] = '/'; 1370 slash_prefixed = 1; 1371 } 1372 if (error) 1373 return (error); 1374 if (!slash_prefixed) { 1375 if (buflen == 0) { 1376 CACHE_RUNLOCK(); 1377 vrele(vp); 1378 numfullpathfail4++; 1379 SDT_PROBE3(vfs, namecache, fullpath, return, ENOMEM, 1380 startvp, NULL); 1381 return (ENOMEM); 1382 } 1383 buf[--buflen] = '/'; 1384 } 1385 numfullpathfound++; 1386 CACHE_RUNLOCK(); 1387 vrele(vp); 1388 1389 SDT_PROBE3(vfs, namecache, fullpath, return, 0, startvp, buf + buflen); 1390 *retbuf = buf + buflen; 1391 return (0); 1392 } 1393 1394 struct vnode * 1395 vn_dir_dd_ino(struct vnode *vp) 1396 { 1397 struct namecache *ncp; 1398 struct vnode *ddvp; 1399 1400 ASSERT_VOP_LOCKED(vp, "vn_dir_dd_ino"); 1401 CACHE_RLOCK(); 1402 TAILQ_FOREACH(ncp, &(vp->v_cache_dst), nc_dst) { 1403 if ((ncp->nc_flag & NCF_ISDOTDOT) != 0) 1404 continue; 1405 ddvp = ncp->nc_dvp; 1406 vhold(ddvp); 1407 CACHE_RUNLOCK(); 1408 if (vget(ddvp, LK_SHARED | LK_NOWAIT | LK_VNHELD, curthread)) 1409 return (NULL); 1410 return (ddvp); 1411 } 1412 CACHE_RUNLOCK(); 1413 return (NULL); 1414 } 1415 1416 int 1417 vn_commname(struct vnode *vp, char *buf, u_int buflen) 1418 { 1419 struct namecache *ncp; 1420 int l; 1421 1422 CACHE_RLOCK(); 1423 TAILQ_FOREACH(ncp, &vp->v_cache_dst, nc_dst) 1424 if ((ncp->nc_flag & NCF_ISDOTDOT) == 0) 1425 break; 1426 if (ncp == NULL) { 1427 CACHE_RUNLOCK(); 1428 return (ENOENT); 1429 } 1430 l = min(ncp->nc_nlen, buflen - 1); 1431 memcpy(buf, nc_get_name(ncp), l); 1432 CACHE_RUNLOCK(); 1433 buf[l] = '\0'; 1434 return (0); 1435 } 1436 1437 /* ABI compat shims for old kernel modules. */ 1438 #undef cache_enter 1439 1440 void cache_enter(struct vnode *dvp, struct vnode *vp, 1441 struct componentname *cnp); 1442 1443 void 1444 cache_enter(struct vnode *dvp, struct vnode *vp, struct componentname *cnp) 1445 { 1446 1447 cache_enter_time(dvp, vp, cnp, NULL, NULL); 1448 } 1449 1450 /* 1451 * This function updates path string to vnode's full global path 1452 * and checks the size of the new path string against the pathlen argument. 1453 * 1454 * Requires a locked, referenced vnode. 1455 * Vnode is re-locked on success or ENODEV, otherwise unlocked. 1456 * 1457 * If sysctl debug.disablefullpath is set, ENODEV is returned, 1458 * vnode is left locked and path remain untouched. 1459 * 1460 * If vp is a directory, the call to vn_fullpath_global() always succeeds 1461 * because it falls back to the ".." lookup if the namecache lookup fails. 1462 */ 1463 int 1464 vn_path_to_global_path(struct thread *td, struct vnode *vp, char *path, 1465 u_int pathlen) 1466 { 1467 struct nameidata nd; 1468 struct vnode *vp1; 1469 char *rpath, *fbuf; 1470 int error; 1471 1472 ASSERT_VOP_ELOCKED(vp, __func__); 1473 1474 /* Return ENODEV if sysctl debug.disablefullpath==1 */ 1475 if (disablefullpath) 1476 return (ENODEV); 1477 1478 /* Construct global filesystem path from vp. */ 1479 VOP_UNLOCK(vp, 0); 1480 error = vn_fullpath_global(td, vp, &rpath, &fbuf); 1481 1482 if (error != 0) { 1483 vrele(vp); 1484 return (error); 1485 } 1486 1487 if (strlen(rpath) >= pathlen) { 1488 vrele(vp); 1489 error = ENAMETOOLONG; 1490 goto out; 1491 } 1492 1493 /* 1494 * Re-lookup the vnode by path to detect a possible rename. 1495 * As a side effect, the vnode is relocked. 1496 * If vnode was renamed, return ENOENT. 1497 */ 1498 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNODE1, 1499 UIO_SYSSPACE, path, td); 1500 error = namei(&nd); 1501 if (error != 0) { 1502 vrele(vp); 1503 goto out; 1504 } 1505 NDFREE(&nd, NDF_ONLY_PNBUF); 1506 vp1 = nd.ni_vp; 1507 vrele(vp); 1508 if (vp1 == vp) 1509 strcpy(path, rpath); 1510 else { 1511 vput(vp1); 1512 error = ENOENT; 1513 } 1514 1515 out: 1516 free(fbuf, M_TEMP); 1517 return (error); 1518 } 1519