Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]
FreeBSD/Linux Kernel Cross Reference
sys/kern/vfs_cache.c
Version:
- FREEBSD - FREEBSD-13-STABLE - FREEBSD-13-0 - FREEBSD-12-STABLE - FREEBSD-12-0 - FREEBSD-11-STABLE - FREEBSD-11-0 - FREEBSD-10-STABLE - FREEBSD-10-0 - FREEBSD-9-STABLE - FREEBSD-9-0 - FREEBSD-8-STABLE - FREEBSD-8-0 - FREEBSD-7-STABLE - FREEBSD-7-0 - FREEBSD-6-STABLE - FREEBSD-6-0 - FREEBSD-5-STABLE - FREEBSD-5-0 - FREEBSD-4-STABLE - FREEBSD-3-STABLE - FREEBSD22 - l41 - OPENBSD - linux-2.6 - MK84 - PLAN9 - xnu-8792
SearchContext: - none - 3 - 10
SearchContext: - none - 3 - 10
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: releng/8.3/sys/kern/vfs_cache.c 230168 2012-01-15 22:02:35Z avg $"); 37 38 #include "opt_kdtrace.h" 39 #include "opt_ktrace.h" 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/filedesc.h> 44 #include <sys/fnv_hash.h> 45 #include <sys/kernel.h> 46 #include <sys/lock.h> 47 #include <sys/malloc.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, done, "struct vnode *", "char *", 65 "struct vnode *"); 66 SDT_PROBE_DEFINE2(vfs, namecache, enter_negative, done, done, "struct vnode *", 67 "char *"); 68 SDT_PROBE_DEFINE1(vfs, namecache, fullpath, entry, entry, "struct vnode *"); 69 SDT_PROBE_DEFINE3(vfs, namecache, fullpath, hit, hit, "struct vnode *", 70 "struct char *", "struct vnode *"); 71 SDT_PROBE_DEFINE1(vfs, namecache, fullpath, miss, miss, "struct vnode *"); 72 SDT_PROBE_DEFINE3(vfs, namecache, fullpath, return, return, "int", 73 "struct vnode *", "struct char *"); 74 SDT_PROBE_DEFINE3(vfs, namecache, lookup, hit, hit, "struct vnode *", "char *", 75 "struct vnode *"); 76 SDT_PROBE_DEFINE2(vfs, namecache, lookup, hit_negative, hit-negative, 77 "struct vnode *", "char *"); 78 SDT_PROBE_DEFINE2(vfs, namecache, lookup, miss, miss, "struct vnode *", 79 "char *"); 80 SDT_PROBE_DEFINE1(vfs, namecache, purge, done, done, "struct vnode *"); 81 SDT_PROBE_DEFINE1(vfs, namecache, purge_negative, done, done, "struct vnode *"); 82 SDT_PROBE_DEFINE1(vfs, namecache, purgevfs, done, done, "struct mount *"); 83 SDT_PROBE_DEFINE3(vfs, namecache, zap, done, done, "struct vnode *", "char *", 84 "struct vnode *"); 85 SDT_PROBE_DEFINE2(vfs, namecache, zap_negative, done, 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 * Name caching works as follows: 106 * 107 * Names found by directory scans are retained in a cache 108 * for future reference. It is managed LRU, so frequently 109 * used names will hang around. Cache is indexed by hash value 110 * obtained from (vp, name) where vp refers to the directory 111 * containing name. 112 * 113 * If it is a "negative" entry, (i.e. for a name that is known NOT to 114 * exist) the vnode pointer will be NULL. 115 * 116 * Upon reaching the last segment of a path, if the reference 117 * is for DELETE, or NOCACHE is set (rewrite), and the 118 * name is located in the cache, it will be dropped. 119 */ 120 121 /* 122 * Structures associated with name cacheing. 123 */ 124 #define NCHHASH(hash) \ 125 (&nchashtbl[(hash) & nchash]) 126 static LIST_HEAD(nchashhead, namecache) *nchashtbl; /* Hash Table */ 127 static TAILQ_HEAD(, namecache) ncneg; /* Hash Table */ 128 static u_long nchash; /* size of hash table */ 129 SYSCTL_ULONG(_debug, OID_AUTO, nchash, CTLFLAG_RD, &nchash, 0, 130 "Size of namecache hash table"); 131 static u_long ncnegfactor = 16; /* ratio of negative entries */ 132 /* _debug sysctl left for backward compatibility */ 133 SYSCTL_ULONG(_debug, OID_AUTO, ncnegfactor, CTLFLAG_RW, &ncnegfactor, 0, ""); 134 SYSCTL_ULONG(_vfs, OID_AUTO, ncnegfactor, CTLFLAG_RW, &ncnegfactor, 0, 135 "Ratio of negative namecache entries"); 136 static u_long numneg; /* number of negative entries allocated */ 137 SYSCTL_ULONG(_debug, OID_AUTO, numneg, CTLFLAG_RD, &numneg, 0, 138 "Number of negative entries in namecache"); 139 static u_long numcache; /* number of cache entries allocated */ 140 SYSCTL_ULONG(_debug, OID_AUTO, numcache, CTLFLAG_RD, &numcache, 0, 141 "Number of namecache entries"); 142 static u_long numcachehv; /* number of cache entries with vnodes held */ 143 SYSCTL_ULONG(_debug, OID_AUTO, numcachehv, CTLFLAG_RD, &numcachehv, 0, 144 "Number of namecache entries with vnodes held"); 145 static u_int ncsizefactor = 2; 146 SYSCTL_UINT(_vfs, OID_AUTO, ncsizefactor, CTLFLAG_RW, &ncsizefactor, 0, 147 "Size factor for namecache"); 148 149 struct nchstats nchstats; /* cache effectiveness statistics */ 150 151 static struct rwlock cache_lock; 152 RW_SYSINIT(vfscache, &cache_lock, "Name Cache"); 153 154 #define CACHE_UPGRADE_LOCK() rw_try_upgrade(&cache_lock) 155 #define CACHE_RLOCK() rw_rlock(&cache_lock) 156 #define CACHE_RUNLOCK() rw_runlock(&cache_lock) 157 #define CACHE_WLOCK() rw_wlock(&cache_lock) 158 #define CACHE_WUNLOCK() rw_wunlock(&cache_lock) 159 160 /* 161 * UMA zones for the VFS cache. 162 * 163 * The small cache is used for entries with short names, which are the 164 * most common. The large cache is used for entries which are too big to 165 * fit in the small cache. 166 */ 167 static uma_zone_t cache_zone_small; 168 static uma_zone_t cache_zone_large; 169 170 #define CACHE_PATH_CUTOFF 35 171 #define CACHE_ZONE_SMALL (sizeof(struct namecache) + CACHE_PATH_CUTOFF \ 172 + 1) 173 #define CACHE_ZONE_LARGE (sizeof(struct namecache) + NAME_MAX + 1) 174 175 #define cache_alloc(len) uma_zalloc(((len) <= CACHE_PATH_CUTOFF) ? \ 176 cache_zone_small : cache_zone_large, M_WAITOK) 177 #define cache_free(ncp) do { \ 178 if (ncp != NULL) \ 179 uma_zfree(((ncp)->nc_nlen <= CACHE_PATH_CUTOFF) ? \ 180 cache_zone_small : cache_zone_large, (ncp)); \ 181 } while (0) 182 183 static int doingcache = 1; /* 1 => enable the cache */ 184 SYSCTL_INT(_debug, OID_AUTO, vfscache, CTLFLAG_RW, &doingcache, 0, 185 "VFS namecache enabled"); 186 187 /* Export size information to userland */ 188 SYSCTL_INT(_debug_sizeof, OID_AUTO, namecache, CTLFLAG_RD, 0, 189 sizeof(struct namecache), "sizeof(struct namecache)"); 190 191 /* 192 * The new name cache statistics 193 */ 194 static SYSCTL_NODE(_vfs, OID_AUTO, cache, CTLFLAG_RW, 0, 195 "Name cache statistics"); 196 #define STATNODE(mode, name, var, descr) \ 197 SYSCTL_ULONG(_vfs_cache, OID_AUTO, name, mode, var, 0, descr); 198 STATNODE(CTLFLAG_RD, numneg, &numneg, "Number of negative cache entries"); 199 STATNODE(CTLFLAG_RD, numcache, &numcache, "Number of cache entries"); 200 static u_long numcalls; STATNODE(CTLFLAG_RD, numcalls, &numcalls, 201 "Number of cache lookups"); 202 static u_long dothits; STATNODE(CTLFLAG_RD, dothits, &dothits, 203 "Number of '.' hits"); 204 static u_long dotdothits; STATNODE(CTLFLAG_RD, dotdothits, &dotdothits, 205 "Number of '..' hits"); 206 static u_long numchecks; STATNODE(CTLFLAG_RD, numchecks, &numchecks, 207 "Number of checks in lookup"); 208 static u_long nummiss; STATNODE(CTLFLAG_RD, nummiss, &nummiss, 209 "Number of cache misses"); 210 static u_long nummisszap; STATNODE(CTLFLAG_RD, nummisszap, &nummisszap, 211 "Number of cache misses we do not want to cache"); 212 static u_long numposzaps; STATNODE(CTLFLAG_RD, numposzaps, &numposzaps, 213 "Number of cache hits (positive) we do not want to cache"); 214 static u_long numposhits; STATNODE(CTLFLAG_RD, numposhits, &numposhits, 215 "Number of cache hits (positive)"); 216 static u_long numnegzaps; STATNODE(CTLFLAG_RD, numnegzaps, &numnegzaps, 217 "Number of cache hits (negative) we do not want to cache"); 218 static u_long numneghits; STATNODE(CTLFLAG_RD, numneghits, &numneghits, 219 "Number of cache hits (negative)"); 220 static u_long numupgrades; STATNODE(CTLFLAG_RD, numupgrades, &numupgrades, 221 "Number of updates of the cache after lookup (write lock + retry)"); 222 223 SYSCTL_OPAQUE(_vfs_cache, OID_AUTO, nchstats, CTLFLAG_RD | CTLFLAG_MPSAFE, 224 &nchstats, sizeof(nchstats), "LU", 225 "VFS cache effectiveness statistics"); 226 227 228 229 static void cache_zap(struct namecache *ncp); 230 static int vn_vptocnp_locked(struct vnode **vp, struct ucred *cred, char *buf, 231 u_int *buflen); 232 static int vn_fullpath1(struct thread *td, struct vnode *vp, struct vnode *rdir, 233 char *buf, char **retbuf, u_int buflen); 234 235 static MALLOC_DEFINE(M_VFSCACHE, "vfscache", "VFS name cache entries"); 236 237 /* 238 * Flags in namecache.nc_flag 239 */ 240 #define NCF_WHITE 0x01 241 #define NCF_ISDOTDOT 0x02 242 243 #ifdef DIAGNOSTIC 244 /* 245 * Grab an atomic snapshot of the name cache hash chain lengths 246 */ 247 SYSCTL_NODE(_debug, OID_AUTO, hashstat, CTLFLAG_RW, NULL, "hash table stats"); 248 249 static int 250 sysctl_debug_hashstat_rawnchash(SYSCTL_HANDLER_ARGS) 251 { 252 int error; 253 struct nchashhead *ncpp; 254 struct namecache *ncp; 255 int n_nchash; 256 int count; 257 258 n_nchash = nchash + 1; /* nchash is max index, not count */ 259 if (!req->oldptr) 260 return SYSCTL_OUT(req, 0, n_nchash * sizeof(int)); 261 262 /* Scan hash tables for applicable entries */ 263 for (ncpp = nchashtbl; n_nchash > 0; n_nchash--, ncpp++) { 264 CACHE_RLOCK(); 265 count = 0; 266 LIST_FOREACH(ncp, ncpp, nc_hash) { 267 count++; 268 } 269 CACHE_RUNLOCK(); 270 error = SYSCTL_OUT(req, &count, sizeof(count)); 271 if (error) 272 return (error); 273 } 274 return (0); 275 } 276 SYSCTL_PROC(_debug_hashstat, OID_AUTO, rawnchash, CTLTYPE_INT|CTLFLAG_RD| 277 CTLFLAG_MPSAFE, 0, 0, sysctl_debug_hashstat_rawnchash, "S,int", 278 "nchash chain lengths"); 279 280 static int 281 sysctl_debug_hashstat_nchash(SYSCTL_HANDLER_ARGS) 282 { 283 int error; 284 struct nchashhead *ncpp; 285 struct namecache *ncp; 286 int n_nchash; 287 int count, maxlength, used, pct; 288 289 if (!req->oldptr) 290 return SYSCTL_OUT(req, 0, 4 * sizeof(int)); 291 292 n_nchash = nchash + 1; /* nchash is max index, not count */ 293 used = 0; 294 maxlength = 0; 295 296 /* Scan hash tables for applicable entries */ 297 for (ncpp = nchashtbl; n_nchash > 0; n_nchash--, ncpp++) { 298 count = 0; 299 CACHE_RLOCK(); 300 LIST_FOREACH(ncp, ncpp, nc_hash) { 301 count++; 302 } 303 CACHE_RUNLOCK(); 304 if (count) 305 used++; 306 if (maxlength < count) 307 maxlength = count; 308 } 309 n_nchash = nchash + 1; 310 pct = (used * 100 * 100) / n_nchash; 311 error = SYSCTL_OUT(req, &n_nchash, sizeof(n_nchash)); 312 if (error) 313 return (error); 314 error = SYSCTL_OUT(req, &used, sizeof(used)); 315 if (error) 316 return (error); 317 error = SYSCTL_OUT(req, &maxlength, sizeof(maxlength)); 318 if (error) 319 return (error); 320 error = SYSCTL_OUT(req, &pct, sizeof(pct)); 321 if (error) 322 return (error); 323 return (0); 324 } 325 SYSCTL_PROC(_debug_hashstat, OID_AUTO, nchash, CTLTYPE_INT|CTLFLAG_RD| 326 CTLFLAG_MPSAFE, 0, 0, sysctl_debug_hashstat_nchash, "I", 327 "nchash chain lengths"); 328 #endif 329 330 /* 331 * cache_zap(): 332 * 333 * Removes a namecache entry from cache, whether it contains an actual 334 * pointer to a vnode or if it is just a negative cache entry. 335 */ 336 static void 337 cache_zap(ncp) 338 struct namecache *ncp; 339 { 340 struct vnode *vp; 341 342 rw_assert(&cache_lock, RA_WLOCKED); 343 CTR2(KTR_VFS, "cache_zap(%p) vp %p", ncp, ncp->nc_vp); 344 #ifdef KDTRACE_HOOKS 345 if (ncp->nc_vp != NULL) { 346 SDT_PROBE(vfs, namecache, zap, done, ncp->nc_dvp, 347 ncp->nc_name, ncp->nc_vp, 0, 0); 348 } else { 349 SDT_PROBE(vfs, namecache, zap_negative, done, ncp->nc_dvp, 350 ncp->nc_name, 0, 0, 0); 351 } 352 #endif 353 vp = NULL; 354 LIST_REMOVE(ncp, nc_hash); 355 if (ncp->nc_flag & NCF_ISDOTDOT) { 356 if (ncp == ncp->nc_dvp->v_cache_dd) 357 ncp->nc_dvp->v_cache_dd = NULL; 358 } else { 359 LIST_REMOVE(ncp, nc_src); 360 if (LIST_EMPTY(&ncp->nc_dvp->v_cache_src)) { 361 vp = ncp->nc_dvp; 362 numcachehv--; 363 } 364 } 365 if (ncp->nc_vp) { 366 TAILQ_REMOVE(&ncp->nc_vp->v_cache_dst, ncp, nc_dst); 367 if (ncp == ncp->nc_vp->v_cache_dd) 368 ncp->nc_vp->v_cache_dd = NULL; 369 } else { 370 TAILQ_REMOVE(&ncneg, ncp, nc_dst); 371 numneg--; 372 } 373 numcache--; 374 cache_free(ncp); 375 if (vp) 376 vdrop(vp); 377 } 378 379 /* 380 * Lookup an entry in the cache 381 * 382 * Lookup is called with dvp pointing to the directory to search, 383 * cnp pointing to the name of the entry being sought. If the lookup 384 * succeeds, the vnode is returned in *vpp, and a status of -1 is 385 * returned. If the lookup determines that the name does not exist 386 * (negative cacheing), a status of ENOENT is returned. If the lookup 387 * fails, a status of zero is returned. If the directory vnode is 388 * recycled out from under us due to a forced unmount, a status of 389 * ENOENT is returned. 390 * 391 * vpp is locked and ref'd on return. If we're looking up DOTDOT, dvp is 392 * unlocked. If we're looking up . an extra ref is taken, but the lock is 393 * not recursively acquired. 394 */ 395 396 int 397 cache_lookup(dvp, vpp, cnp) 398 struct vnode *dvp; 399 struct vnode **vpp; 400 struct componentname *cnp; 401 { 402 struct namecache *ncp; 403 u_int32_t hash; 404 int error, ltype, wlocked; 405 406 if (!doingcache) { 407 cnp->cn_flags &= ~MAKEENTRY; 408 return (0); 409 } 410 retry: 411 CACHE_RLOCK(); 412 wlocked = 0; 413 numcalls++; 414 error = 0; 415 416 retry_wlocked: 417 if (cnp->cn_nameptr[0] == '.') { 418 if (cnp->cn_namelen == 1) { 419 *vpp = dvp; 420 CTR2(KTR_VFS, "cache_lookup(%p, %s) found via .", 421 dvp, cnp->cn_nameptr); 422 dothits++; 423 SDT_PROBE(vfs, namecache, lookup, hit, dvp, ".", 424 *vpp, 0, 0); 425 goto success; 426 } 427 if (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.') { 428 dotdothits++; 429 if (dvp->v_cache_dd == NULL) { 430 SDT_PROBE(vfs, namecache, lookup, miss, dvp, 431 "..", NULL, 0, 0); 432 goto unlock; 433 } 434 if ((cnp->cn_flags & MAKEENTRY) == 0) { 435 if (!wlocked && !CACHE_UPGRADE_LOCK()) 436 goto wlock; 437 if (dvp->v_cache_dd->nc_flag & NCF_ISDOTDOT) 438 cache_zap(dvp->v_cache_dd); 439 dvp->v_cache_dd = NULL; 440 CACHE_WUNLOCK(); 441 return (0); 442 } 443 if (dvp->v_cache_dd->nc_flag & NCF_ISDOTDOT) 444 *vpp = dvp->v_cache_dd->nc_vp; 445 else 446 *vpp = dvp->v_cache_dd->nc_dvp; 447 /* Return failure if negative entry was found. */ 448 if (*vpp == NULL) { 449 ncp = dvp->v_cache_dd; 450 goto negative_success; 451 } 452 CTR3(KTR_VFS, "cache_lookup(%p, %s) found %p via ..", 453 dvp, cnp->cn_nameptr, *vpp); 454 SDT_PROBE(vfs, namecache, lookup, hit, dvp, "..", 455 *vpp, 0, 0); 456 goto success; 457 } 458 } 459 460 hash = fnv_32_buf(cnp->cn_nameptr, cnp->cn_namelen, FNV1_32_INIT); 461 hash = fnv_32_buf(&dvp, sizeof(dvp), hash); 462 LIST_FOREACH(ncp, (NCHHASH(hash)), nc_hash) { 463 numchecks++; 464 if (ncp->nc_dvp == dvp && ncp->nc_nlen == cnp->cn_namelen && 465 !bcmp(ncp->nc_name, cnp->cn_nameptr, ncp->nc_nlen)) 466 break; 467 } 468 469 /* We failed to find an entry */ 470 if (ncp == NULL) { 471 SDT_PROBE(vfs, namecache, lookup, miss, dvp, cnp->cn_nameptr, 472 NULL, 0, 0); 473 if ((cnp->cn_flags & MAKEENTRY) == 0) { 474 nummisszap++; 475 } else { 476 nummiss++; 477 } 478 nchstats.ncs_miss++; 479 goto unlock; 480 } 481 482 /* We don't want to have an entry, so dump it */ 483 if ((cnp->cn_flags & MAKEENTRY) == 0) { 484 numposzaps++; 485 nchstats.ncs_badhits++; 486 if (!wlocked && !CACHE_UPGRADE_LOCK()) 487 goto wlock; 488 cache_zap(ncp); 489 CACHE_WUNLOCK(); 490 return (0); 491 } 492 493 /* We found a "positive" match, return the vnode */ 494 if (ncp->nc_vp) { 495 numposhits++; 496 nchstats.ncs_goodhits++; 497 *vpp = ncp->nc_vp; 498 CTR4(KTR_VFS, "cache_lookup(%p, %s) found %p via ncp %p", 499 dvp, cnp->cn_nameptr, *vpp, ncp); 500 SDT_PROBE(vfs, namecache, lookup, hit, dvp, ncp->nc_name, 501 *vpp, 0, 0); 502 goto success; 503 } 504 505 negative_success: 506 /* We found a negative match, and want to create it, so purge */ 507 if (cnp->cn_nameiop == CREATE) { 508 numnegzaps++; 509 nchstats.ncs_badhits++; 510 if (!wlocked && !CACHE_UPGRADE_LOCK()) 511 goto wlock; 512 cache_zap(ncp); 513 CACHE_WUNLOCK(); 514 return (0); 515 } 516 517 if (!wlocked && !CACHE_UPGRADE_LOCK()) 518 goto wlock; 519 numneghits++; 520 /* 521 * We found a "negative" match, so we shift it to the end of 522 * the "negative" cache entries queue to satisfy LRU. Also, 523 * check to see if the entry is a whiteout; indicate this to 524 * the componentname, if so. 525 */ 526 TAILQ_REMOVE(&ncneg, ncp, nc_dst); 527 TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst); 528 nchstats.ncs_neghits++; 529 if (ncp->nc_flag & NCF_WHITE) 530 cnp->cn_flags |= ISWHITEOUT; 531 SDT_PROBE(vfs, namecache, lookup, hit_negative, dvp, ncp->nc_name, 532 0, 0, 0); 533 CACHE_WUNLOCK(); 534 return (ENOENT); 535 536 wlock: 537 /* 538 * We need to update the cache after our lookup, so upgrade to 539 * a write lock and retry the operation. 540 */ 541 CACHE_RUNLOCK(); 542 CACHE_WLOCK(); 543 numupgrades++; 544 wlocked = 1; 545 goto retry_wlocked; 546 547 success: 548 /* 549 * On success we return a locked and ref'd vnode as per the lookup 550 * protocol. 551 */ 552 if (dvp == *vpp) { /* lookup on "." */ 553 VREF(*vpp); 554 if (wlocked) 555 CACHE_WUNLOCK(); 556 else 557 CACHE_RUNLOCK(); 558 /* 559 * When we lookup "." we still can be asked to lock it 560 * differently... 561 */ 562 ltype = cnp->cn_lkflags & LK_TYPE_MASK; 563 if (ltype != VOP_ISLOCKED(*vpp)) { 564 if (ltype == LK_EXCLUSIVE) { 565 vn_lock(*vpp, LK_UPGRADE | LK_RETRY); 566 if ((*vpp)->v_iflag & VI_DOOMED) { 567 /* forced unmount */ 568 vrele(*vpp); 569 *vpp = NULL; 570 return (ENOENT); 571 } 572 } else 573 vn_lock(*vpp, LK_DOWNGRADE | LK_RETRY); 574 } 575 return (-1); 576 } 577 ltype = 0; /* silence gcc warning */ 578 if (cnp->cn_flags & ISDOTDOT) { 579 ltype = VOP_ISLOCKED(dvp); 580 VOP_UNLOCK(dvp, 0); 581 } 582 VI_LOCK(*vpp); 583 if (wlocked) 584 CACHE_WUNLOCK(); 585 else 586 CACHE_RUNLOCK(); 587 error = vget(*vpp, cnp->cn_lkflags | LK_INTERLOCK, cnp->cn_thread); 588 if (cnp->cn_flags & ISDOTDOT) { 589 vn_lock(dvp, ltype | LK_RETRY); 590 if (dvp->v_iflag & VI_DOOMED) { 591 if (error == 0) 592 vput(*vpp); 593 *vpp = NULL; 594 return (ENOENT); 595 } 596 } 597 if (error) { 598 *vpp = NULL; 599 goto retry; 600 } 601 if ((cnp->cn_flags & ISLASTCN) && 602 (cnp->cn_lkflags & LK_TYPE_MASK) == LK_EXCLUSIVE) { 603 ASSERT_VOP_ELOCKED(*vpp, "cache_lookup"); 604 } 605 return (-1); 606 607 unlock: 608 if (wlocked) 609 CACHE_WUNLOCK(); 610 else 611 CACHE_RUNLOCK(); 612 return (0); 613 } 614 615 /* 616 * Add an entry to the cache. 617 */ 618 void 619 cache_enter(dvp, vp, cnp) 620 struct vnode *dvp; 621 struct vnode *vp; 622 struct componentname *cnp; 623 { 624 struct namecache *ncp, *n2; 625 struct nchashhead *ncpp; 626 u_int32_t hash; 627 int flag; 628 int hold; 629 int zap; 630 int len; 631 632 CTR3(KTR_VFS, "cache_enter(%p, %p, %s)", dvp, vp, cnp->cn_nameptr); 633 VNASSERT(vp == NULL || (vp->v_iflag & VI_DOOMED) == 0, vp, 634 ("cache_enter: Adding a doomed vnode")); 635 VNASSERT(dvp == NULL || (dvp->v_iflag & VI_DOOMED) == 0, dvp, 636 ("cache_enter: Doomed vnode used as src")); 637 638 if (!doingcache) 639 return; 640 641 /* 642 * Avoid blowout in namecache entries. 643 */ 644 if (numcache >= desiredvnodes * ncsizefactor) 645 return; 646 647 flag = 0; 648 if (cnp->cn_nameptr[0] == '.') { 649 if (cnp->cn_namelen == 1) 650 return; 651 if (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.') { 652 CACHE_WLOCK(); 653 /* 654 * If dotdot entry already exists, just retarget it 655 * to new parent vnode, otherwise continue with new 656 * namecache entry allocation. 657 */ 658 if ((ncp = dvp->v_cache_dd) != NULL && 659 ncp->nc_flag & NCF_ISDOTDOT) { 660 KASSERT(ncp->nc_dvp == dvp, 661 ("wrong isdotdot parent")); 662 if (ncp->nc_vp != NULL) 663 TAILQ_REMOVE(&ncp->nc_vp->v_cache_dst, 664 ncp, nc_dst); 665 else 666 TAILQ_REMOVE(&ncneg, ncp, nc_dst); 667 if (vp != NULL) 668 TAILQ_INSERT_HEAD(&vp->v_cache_dst, 669 ncp, nc_dst); 670 else 671 TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst); 672 ncp->nc_vp = vp; 673 CACHE_WUNLOCK(); 674 return; 675 } 676 dvp->v_cache_dd = NULL; 677 SDT_PROBE(vfs, namecache, enter, done, dvp, "..", vp, 678 0, 0); 679 CACHE_WUNLOCK(); 680 flag = NCF_ISDOTDOT; 681 } 682 } 683 684 hold = 0; 685 zap = 0; 686 687 /* 688 * Calculate the hash key and setup as much of the new 689 * namecache entry as possible before acquiring the lock. 690 */ 691 ncp = cache_alloc(cnp->cn_namelen); 692 ncp->nc_vp = vp; 693 ncp->nc_dvp = dvp; 694 ncp->nc_flag = flag; 695 len = ncp->nc_nlen = cnp->cn_namelen; 696 hash = fnv_32_buf(cnp->cn_nameptr, len, FNV1_32_INIT); 697 strlcpy(ncp->nc_name, cnp->cn_nameptr, len + 1); 698 hash = fnv_32_buf(&dvp, sizeof(dvp), hash); 699 CACHE_WLOCK(); 700 701 /* 702 * See if this vnode or negative entry is already in the cache 703 * with this name. This can happen with concurrent lookups of 704 * the same path name. 705 */ 706 ncpp = NCHHASH(hash); 707 LIST_FOREACH(n2, ncpp, nc_hash) { 708 if (n2->nc_dvp == dvp && 709 n2->nc_nlen == cnp->cn_namelen && 710 !bcmp(n2->nc_name, cnp->cn_nameptr, n2->nc_nlen)) { 711 CACHE_WUNLOCK(); 712 cache_free(ncp); 713 return; 714 } 715 } 716 717 if (flag == NCF_ISDOTDOT) { 718 /* 719 * See if we are trying to add .. entry, but some other lookup 720 * has populated v_cache_dd pointer already. 721 */ 722 if (dvp->v_cache_dd != NULL) { 723 CACHE_WUNLOCK(); 724 cache_free(ncp); 725 return; 726 } 727 KASSERT(vp == NULL || vp->v_type == VDIR, 728 ("wrong vnode type %p", vp)); 729 dvp->v_cache_dd = ncp; 730 } 731 732 numcache++; 733 if (!vp) { 734 numneg++; 735 if (cnp->cn_flags & ISWHITEOUT) 736 ncp->nc_flag |= NCF_WHITE; 737 } else if (vp->v_type == VDIR) { 738 if (flag != NCF_ISDOTDOT) { 739 if ((n2 = vp->v_cache_dd) != NULL && 740 (n2->nc_flag & NCF_ISDOTDOT) != 0) 741 cache_zap(n2); 742 vp->v_cache_dd = ncp; 743 } 744 } else { 745 vp->v_cache_dd = NULL; 746 } 747 748 /* 749 * Insert the new namecache entry into the appropriate chain 750 * within the cache entries table. 751 */ 752 LIST_INSERT_HEAD(ncpp, ncp, nc_hash); 753 if (flag != NCF_ISDOTDOT) { 754 if (LIST_EMPTY(&dvp->v_cache_src)) { 755 hold = 1; 756 numcachehv++; 757 } 758 LIST_INSERT_HEAD(&dvp->v_cache_src, ncp, nc_src); 759 } 760 761 /* 762 * If the entry is "negative", we place it into the 763 * "negative" cache queue, otherwise, we place it into the 764 * destination vnode's cache entries queue. 765 */ 766 if (vp) { 767 TAILQ_INSERT_HEAD(&vp->v_cache_dst, ncp, nc_dst); 768 SDT_PROBE(vfs, namecache, enter, done, dvp, ncp->nc_name, vp, 769 0, 0); 770 } else { 771 TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst); 772 SDT_PROBE(vfs, namecache, enter_negative, done, dvp, 773 ncp->nc_name, 0, 0, 0); 774 } 775 if (numneg * ncnegfactor > numcache) { 776 ncp = TAILQ_FIRST(&ncneg); 777 zap = 1; 778 } 779 if (hold) 780 vhold(dvp); 781 if (zap) 782 cache_zap(ncp); 783 CACHE_WUNLOCK(); 784 } 785 786 /* 787 * Name cache initialization, from vfs_init() when we are booting 788 */ 789 static void 790 nchinit(void *dummy __unused) 791 { 792 793 TAILQ_INIT(&ncneg); 794 795 cache_zone_small = uma_zcreate("S VFS Cache", CACHE_ZONE_SMALL, NULL, 796 NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_ZINIT); 797 cache_zone_large = uma_zcreate("L VFS Cache", CACHE_ZONE_LARGE, NULL, 798 NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_ZINIT); 799 800 nchashtbl = hashinit(desiredvnodes * 2, M_VFSCACHE, &nchash); 801 } 802 SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_SECOND, nchinit, NULL); 803 804 805 /* 806 * Invalidate all entries to a particular vnode. 807 */ 808 void 809 cache_purge(vp) 810 struct vnode *vp; 811 { 812 813 CTR1(KTR_VFS, "cache_purge(%p)", vp); 814 SDT_PROBE(vfs, namecache, purge, done, vp, 0, 0, 0, 0); 815 CACHE_WLOCK(); 816 while (!LIST_EMPTY(&vp->v_cache_src)) 817 cache_zap(LIST_FIRST(&vp->v_cache_src)); 818 while (!TAILQ_EMPTY(&vp->v_cache_dst)) 819 cache_zap(TAILQ_FIRST(&vp->v_cache_dst)); 820 if (vp->v_cache_dd != NULL) { 821 KASSERT(vp->v_cache_dd->nc_flag & NCF_ISDOTDOT, 822 ("lost dotdot link")); 823 cache_zap(vp->v_cache_dd); 824 } 825 KASSERT(vp->v_cache_dd == NULL, ("incomplete purge")); 826 CACHE_WUNLOCK(); 827 } 828 829 /* 830 * Invalidate all negative entries for a particular directory vnode. 831 */ 832 void 833 cache_purge_negative(vp) 834 struct vnode *vp; 835 { 836 struct namecache *cp, *ncp; 837 838 CTR1(KTR_VFS, "cache_purge_negative(%p)", vp); 839 SDT_PROBE(vfs, namecache, purge_negative, done, vp, 0, 0, 0, 0); 840 CACHE_WLOCK(); 841 LIST_FOREACH_SAFE(cp, &vp->v_cache_src, nc_src, ncp) { 842 if (cp->nc_vp == NULL) 843 cache_zap(cp); 844 } 845 CACHE_WUNLOCK(); 846 } 847 848 /* 849 * Flush all entries referencing a particular filesystem. 850 */ 851 void 852 cache_purgevfs(mp) 853 struct mount *mp; 854 { 855 struct nchashhead *ncpp; 856 struct namecache *ncp, *nnp; 857 858 /* Scan hash tables for applicable entries */ 859 SDT_PROBE(vfs, namecache, purgevfs, done, mp, 0, 0, 0, 0); 860 CACHE_WLOCK(); 861 for (ncpp = &nchashtbl[nchash]; ncpp >= nchashtbl; ncpp--) { 862 LIST_FOREACH_SAFE(ncp, ncpp, nc_hash, nnp) { 863 if (ncp->nc_dvp->v_mount == mp) 864 cache_zap(ncp); 865 } 866 } 867 CACHE_WUNLOCK(); 868 } 869 870 /* 871 * Perform canonical checks and cache lookup and pass on to filesystem 872 * through the vop_cachedlookup only if needed. 873 */ 874 875 int 876 vfs_cache_lookup(ap) 877 struct vop_lookup_args /* { 878 struct vnode *a_dvp; 879 struct vnode **a_vpp; 880 struct componentname *a_cnp; 881 } */ *ap; 882 { 883 struct vnode *dvp; 884 int error; 885 struct vnode **vpp = ap->a_vpp; 886 struct componentname *cnp = ap->a_cnp; 887 struct ucred *cred = cnp->cn_cred; 888 int flags = cnp->cn_flags; 889 struct thread *td = cnp->cn_thread; 890 891 *vpp = NULL; 892 dvp = ap->a_dvp; 893 894 if (dvp->v_type != VDIR) 895 return (ENOTDIR); 896 897 if ((flags & ISLASTCN) && (dvp->v_mount->mnt_flag & MNT_RDONLY) && 898 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) 899 return (EROFS); 900 901 error = VOP_ACCESS(dvp, VEXEC, cred, td); 902 if (error) 903 return (error); 904 905 error = cache_lookup(dvp, vpp, cnp); 906 if (error == 0) 907 return (VOP_CACHEDLOOKUP(dvp, vpp, cnp)); 908 if (error == -1) 909 return (0); 910 return (error); 911 } 912 913 914 #ifndef _SYS_SYSPROTO_H_ 915 struct __getcwd_args { 916 u_char *buf; 917 u_int buflen; 918 }; 919 #endif 920 921 /* 922 * XXX All of these sysctls would probably be more productive dead. 923 */ 924 static int disablecwd; 925 SYSCTL_INT(_debug, OID_AUTO, disablecwd, CTLFLAG_RW, &disablecwd, 0, 926 "Disable the getcwd syscall"); 927 928 /* Implementation of the getcwd syscall. */ 929 int 930 __getcwd(td, uap) 931 struct thread *td; 932 struct __getcwd_args *uap; 933 { 934 935 return (kern___getcwd(td, uap->buf, UIO_USERSPACE, uap->buflen)); 936 } 937 938 int 939 kern___getcwd(struct thread *td, u_char *buf, enum uio_seg bufseg, u_int buflen) 940 { 941 char *bp, *tmpbuf; 942 struct filedesc *fdp; 943 struct vnode *cdir, *rdir; 944 int error, vfslocked; 945 946 if (disablecwd) 947 return (ENODEV); 948 if (buflen < 2) 949 return (EINVAL); 950 if (buflen > MAXPATHLEN) 951 buflen = MAXPATHLEN; 952 953 tmpbuf = malloc(buflen, M_TEMP, M_WAITOK); 954 fdp = td->td_proc->p_fd; 955 FILEDESC_SLOCK(fdp); 956 cdir = fdp->fd_cdir; 957 VREF(cdir); 958 rdir = fdp->fd_rdir; 959 VREF(rdir); 960 FILEDESC_SUNLOCK(fdp); 961 error = vn_fullpath1(td, cdir, rdir, tmpbuf, &bp, buflen); 962 vfslocked = VFS_LOCK_GIANT(rdir->v_mount); 963 vrele(rdir); 964 VFS_UNLOCK_GIANT(vfslocked); 965 vfslocked = VFS_LOCK_GIANT(cdir->v_mount); 966 vrele(cdir); 967 VFS_UNLOCK_GIANT(vfslocked); 968 969 if (!error) { 970 if (bufseg == UIO_SYSSPACE) 971 bcopy(bp, buf, strlen(bp) + 1); 972 else 973 error = copyout(bp, buf, strlen(bp) + 1); 974 #ifdef KTRACE 975 if (KTRPOINT(curthread, KTR_NAMEI)) 976 ktrnamei(bp); 977 #endif 978 } 979 free(tmpbuf, M_TEMP); 980 return (error); 981 } 982 983 /* 984 * Thus begins the fullpath magic. 985 */ 986 987 #undef STATNODE 988 #define STATNODE(name, descr) \ 989 static u_int name; \ 990 SYSCTL_UINT(_vfs_cache, OID_AUTO, name, CTLFLAG_RD, &name, 0, descr) 991 992 static int disablefullpath; 993 SYSCTL_INT(_debug, OID_AUTO, disablefullpath, CTLFLAG_RW, &disablefullpath, 0, 994 "Disable the vn_fullpath function"); 995 996 /* These count for kern___getcwd(), too. */ 997 STATNODE(numfullpathcalls, "Number of fullpath search calls"); 998 STATNODE(numfullpathfail1, "Number of fullpath search errors (ENOTDIR)"); 999 STATNODE(numfullpathfail2, 1000 "Number of fullpath search errors (VOP_VPTOCNP failures)"); 1001 STATNODE(numfullpathfail4, "Number of fullpath search errors (ENOMEM)"); 1002 STATNODE(numfullpathfound, "Number of successful fullpath calls"); 1003 1004 /* 1005 * Retrieve the full filesystem path that correspond to a vnode from the name 1006 * cache (if available) 1007 */ 1008 int 1009 vn_fullpath(struct thread *td, struct vnode *vn, char **retbuf, char **freebuf) 1010 { 1011 char *buf; 1012 struct filedesc *fdp; 1013 struct vnode *rdir; 1014 int error, vfslocked; 1015 1016 if (disablefullpath) 1017 return (ENODEV); 1018 if (vn == NULL) 1019 return (EINVAL); 1020 1021 buf = malloc(MAXPATHLEN, M_TEMP, M_WAITOK); 1022 fdp = td->td_proc->p_fd; 1023 FILEDESC_SLOCK(fdp); 1024 rdir = fdp->fd_rdir; 1025 VREF(rdir); 1026 FILEDESC_SUNLOCK(fdp); 1027 error = vn_fullpath1(td, vn, rdir, buf, retbuf, MAXPATHLEN); 1028 vfslocked = VFS_LOCK_GIANT(rdir->v_mount); 1029 vrele(rdir); 1030 VFS_UNLOCK_GIANT(vfslocked); 1031 1032 if (!error) 1033 *freebuf = buf; 1034 else 1035 free(buf, M_TEMP); 1036 return (error); 1037 } 1038 1039 /* 1040 * This function is similar to vn_fullpath, but it attempts to lookup the 1041 * pathname relative to the global root mount point. This is required for the 1042 * auditing sub-system, as audited pathnames must be absolute, relative to the 1043 * global root mount point. 1044 */ 1045 int 1046 vn_fullpath_global(struct thread *td, struct vnode *vn, 1047 char **retbuf, char **freebuf) 1048 { 1049 char *buf; 1050 int error; 1051 1052 if (disablefullpath) 1053 return (ENODEV); 1054 if (vn == NULL) 1055 return (EINVAL); 1056 buf = malloc(MAXPATHLEN, M_TEMP, M_WAITOK); 1057 error = vn_fullpath1(td, vn, rootvnode, buf, retbuf, MAXPATHLEN); 1058 if (!error) 1059 *freebuf = buf; 1060 else 1061 free(buf, M_TEMP); 1062 return (error); 1063 } 1064 1065 int 1066 vn_vptocnp(struct vnode **vp, struct ucred *cred, char *buf, u_int *buflen) 1067 { 1068 int error; 1069 1070 CACHE_RLOCK(); 1071 error = vn_vptocnp_locked(vp, cred, buf, buflen); 1072 if (error == 0) { 1073 /* 1074 * vn_vptocnp_locked() dropped hold acquired by 1075 * VOP_VPTOCNP immediately after locking the 1076 * cache. Since we are going to drop the cache rlock, 1077 * re-hold the result. 1078 */ 1079 vhold(*vp); 1080 CACHE_RUNLOCK(); 1081 } 1082 return (error); 1083 } 1084 1085 static int 1086 vn_vptocnp_locked(struct vnode **vp, struct ucred *cred, char *buf, 1087 u_int *buflen) 1088 { 1089 struct vnode *dvp; 1090 struct namecache *ncp; 1091 int error, vfslocked; 1092 1093 TAILQ_FOREACH(ncp, &((*vp)->v_cache_dst), nc_dst) { 1094 if ((ncp->nc_flag & NCF_ISDOTDOT) == 0) 1095 break; 1096 } 1097 if (ncp != NULL) { 1098 if (*buflen < ncp->nc_nlen) { 1099 CACHE_RUNLOCK(); 1100 numfullpathfail4++; 1101 error = ENOMEM; 1102 SDT_PROBE(vfs, namecache, fullpath, return, error, 1103 vp, NULL, 0, 0); 1104 return (error); 1105 } 1106 *buflen -= ncp->nc_nlen; 1107 memcpy(buf + *buflen, ncp->nc_name, ncp->nc_nlen); 1108 SDT_PROBE(vfs, namecache, fullpath, hit, ncp->nc_dvp, 1109 ncp->nc_name, vp, 0, 0); 1110 *vp = ncp->nc_dvp; 1111 return (0); 1112 } 1113 SDT_PROBE(vfs, namecache, fullpath, miss, vp, 0, 0, 0, 0); 1114 1115 vhold(*vp); 1116 CACHE_RUNLOCK(); 1117 vfslocked = VFS_LOCK_GIANT((*vp)->v_mount); 1118 vn_lock(*vp, LK_SHARED | LK_RETRY); 1119 error = VOP_VPTOCNP(*vp, &dvp, cred, buf, buflen); 1120 VOP_UNLOCK(*vp, 0); 1121 vdrop(*vp); 1122 VFS_UNLOCK_GIANT(vfslocked); 1123 if (error) { 1124 numfullpathfail2++; 1125 SDT_PROBE(vfs, namecache, fullpath, return, error, vp, 1126 NULL, 0, 0); 1127 return (error); 1128 } 1129 1130 *vp = dvp; 1131 CACHE_RLOCK(); 1132 if ((*vp)->v_iflag & VI_DOOMED) { 1133 /* forced unmount */ 1134 CACHE_RUNLOCK(); 1135 vdrop(*vp); 1136 error = ENOENT; 1137 SDT_PROBE(vfs, namecache, fullpath, return, error, vp, 1138 NULL, 0, 0); 1139 return (error); 1140 } 1141 vdrop(*vp); 1142 1143 return (0); 1144 } 1145 1146 /* 1147 * The magic behind kern___getcwd() and vn_fullpath(). 1148 */ 1149 static int 1150 vn_fullpath1(struct thread *td, struct vnode *vp, struct vnode *rdir, 1151 char *buf, char **retbuf, u_int buflen) 1152 { 1153 int error, slash_prefixed; 1154 #ifdef KDTRACE_HOOKS 1155 struct vnode *startvp = vp; 1156 #endif 1157 1158 buflen--; 1159 buf[buflen] = '\0'; 1160 error = 0; 1161 slash_prefixed = 0; 1162 1163 SDT_PROBE(vfs, namecache, fullpath, entry, vp, 0, 0, 0, 0); 1164 numfullpathcalls++; 1165 CACHE_RLOCK(); 1166 if (vp->v_type != VDIR) { 1167 error = vn_vptocnp_locked(&vp, td->td_ucred, buf, &buflen); 1168 if (error) 1169 return (error); 1170 if (buflen == 0) { 1171 CACHE_RUNLOCK(); 1172 return (ENOMEM); 1173 } 1174 buf[--buflen] = '/'; 1175 slash_prefixed = 1; 1176 } 1177 while (vp != rdir && vp != rootvnode) { 1178 if (vp->v_vflag & VV_ROOT) { 1179 if (vp->v_iflag & VI_DOOMED) { /* forced unmount */ 1180 CACHE_RUNLOCK(); 1181 error = ENOENT; 1182 SDT_PROBE(vfs, namecache, fullpath, return, 1183 error, vp, NULL, 0, 0); 1184 break; 1185 } 1186 vp = vp->v_mount->mnt_vnodecovered; 1187 continue; 1188 } 1189 if (vp->v_type != VDIR) { 1190 CACHE_RUNLOCK(); 1191 numfullpathfail1++; 1192 error = ENOTDIR; 1193 SDT_PROBE(vfs, namecache, fullpath, return, 1194 error, vp, NULL, 0, 0); 1195 break; 1196 } 1197 error = vn_vptocnp_locked(&vp, td->td_ucred, buf, &buflen); 1198 if (error) 1199 break; 1200 if (buflen == 0) { 1201 CACHE_RUNLOCK(); 1202 error = ENOMEM; 1203 SDT_PROBE(vfs, namecache, fullpath, return, error, 1204 startvp, NULL, 0, 0); 1205 break; 1206 } 1207 buf[--buflen] = '/'; 1208 slash_prefixed = 1; 1209 } 1210 if (error) 1211 return (error); 1212 if (!slash_prefixed) { 1213 if (buflen == 0) { 1214 CACHE_RUNLOCK(); 1215 numfullpathfail4++; 1216 SDT_PROBE(vfs, namecache, fullpath, return, ENOMEM, 1217 startvp, NULL, 0, 0); 1218 return (ENOMEM); 1219 } 1220 buf[--buflen] = '/'; 1221 } 1222 numfullpathfound++; 1223 CACHE_RUNLOCK(); 1224 1225 SDT_PROBE(vfs, namecache, fullpath, return, 0, startvp, buf + buflen, 1226 0, 0); 1227 *retbuf = buf + buflen; 1228 return (0); 1229 } 1230 1231 int 1232 vn_commname(struct vnode *vp, char *buf, u_int buflen) 1233 { 1234 struct namecache *ncp; 1235 int l; 1236 1237 CACHE_RLOCK(); 1238 TAILQ_FOREACH(ncp, &vp->v_cache_dst, nc_dst) 1239 if ((ncp->nc_flag & NCF_ISDOTDOT) == 0) 1240 break; 1241 if (ncp == NULL) { 1242 CACHE_RUNLOCK(); 1243 return (ENOENT); 1244 } 1245 l = min(ncp->nc_nlen, buflen - 1); 1246 memcpy(buf, ncp->nc_name, l); 1247 CACHE_RUNLOCK(); 1248 buf[l] = '\0'; 1249 return (0); 1250 }
Cache object: bb87856cd81cf2dbcb0ec7b3cb5a403e
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]