1 /* $NetBSD: vfs_cache.c,v 1.64 2006/04/15 04:33:48 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1989, 1993 5 * The Regents of the University of California. All rights reserved. 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 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * @(#)vfs_cache.c 8.3 (Berkeley) 8/22/94 32 */ 33 34 #include <sys/cdefs.h> 35 __KERNEL_RCSID(0, "$NetBSD: vfs_cache.c,v 1.64 2006/04/15 04:33:48 christos Exp $"); 36 37 #include "opt_ddb.h" 38 #include "opt_revcache.h" 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/time.h> 43 #include <sys/mount.h> 44 #include <sys/vnode.h> 45 #include <sys/namei.h> 46 #include <sys/errno.h> 47 #include <sys/malloc.h> 48 #include <sys/pool.h> 49 #include <sys/lock.h> 50 51 /* 52 * Name caching works as follows: 53 * 54 * Names found by directory scans are retained in a cache 55 * for future reference. It is managed LRU, so frequently 56 * used names will hang around. Cache is indexed by hash value 57 * obtained from (dvp, name) where dvp refers to the directory 58 * containing name. 59 * 60 * For simplicity (and economy of storage), names longer than 61 * a maximum length of NCHNAMLEN are not cached; they occur 62 * infrequently in any case, and are almost never of interest. 63 * 64 * Upon reaching the last segment of a path, if the reference 65 * is for DELETE, or NOCACHE is set (rewrite), and the 66 * name is located in the cache, it will be dropped. 67 * The entry is dropped also when it was not possible to lock 68 * the cached vnode, either because vget() failed or the generation 69 * number has changed while waiting for the lock. 70 */ 71 72 /* 73 * Structures associated with name cacheing. 74 */ 75 LIST_HEAD(nchashhead, namecache) *nchashtbl; 76 u_long nchash; /* size of hash table - 1 */ 77 long numcache; /* number of cache entries allocated */ 78 #define NCHASH(cnp, dvp) \ 79 (((cnp)->cn_hash ^ ((uintptr_t)(dvp) >> 3)) & nchash) 80 81 LIST_HEAD(ncvhashhead, namecache) *ncvhashtbl; 82 u_long ncvhash; /* size of hash table - 1 */ 83 #define NCVHASH(vp) (((uintptr_t)(vp) >> 3) & ncvhash) 84 85 TAILQ_HEAD(, namecache) nclruhead; /* LRU chain */ 86 struct nchstats nchstats; /* cache effectiveness statistics */ 87 88 POOL_INIT(namecache_pool, sizeof(struct namecache), 0, 0, 0, "ncachepl", 89 &pool_allocator_nointr); 90 91 MALLOC_DEFINE(M_CACHE, "namecache", "Dynamically allocated cache entries"); 92 93 int doingcache = 1; /* 1 => enable the cache */ 94 95 /* A single lock to protect cache insertion, removal and lookup */ 96 static struct simplelock namecache_slock = SIMPLELOCK_INITIALIZER; 97 98 static void cache_remove(struct namecache *); 99 static void cache_free(struct namecache *); 100 static inline struct namecache *cache_lookup_entry( 101 const struct vnode *, const struct componentname *); 102 103 static void 104 cache_remove(struct namecache *ncp) 105 { 106 107 LOCK_ASSERT(simple_lock_held(&namecache_slock)); 108 109 ncp->nc_dvp = NULL; 110 ncp->nc_vp = NULL; 111 112 TAILQ_REMOVE(&nclruhead, ncp, nc_lru); 113 if (ncp->nc_hash.le_prev != NULL) { 114 LIST_REMOVE(ncp, nc_hash); 115 ncp->nc_hash.le_prev = NULL; 116 } 117 if (ncp->nc_vhash.le_prev != NULL) { 118 LIST_REMOVE(ncp, nc_vhash); 119 ncp->nc_vhash.le_prev = NULL; 120 } 121 if (ncp->nc_vlist.le_prev != NULL) { 122 LIST_REMOVE(ncp, nc_vlist); 123 ncp->nc_vlist.le_prev = NULL; 124 } 125 if (ncp->nc_dvlist.le_prev != NULL) { 126 LIST_REMOVE(ncp, nc_dvlist); 127 ncp->nc_dvlist.le_prev = NULL; 128 } 129 } 130 131 static void 132 cache_free(struct namecache *ncp) 133 { 134 135 pool_put(&namecache_pool, ncp); 136 numcache--; 137 } 138 139 static inline struct namecache * 140 cache_lookup_entry(const struct vnode *dvp, const struct componentname *cnp) 141 { 142 struct nchashhead *ncpp; 143 struct namecache *ncp; 144 145 LOCK_ASSERT(simple_lock_held(&namecache_slock)); 146 147 ncpp = &nchashtbl[NCHASH(cnp, dvp)]; 148 149 LIST_FOREACH(ncp, ncpp, nc_hash) { 150 if (ncp->nc_dvp == dvp && 151 ncp->nc_nlen == cnp->cn_namelen && 152 !memcmp(ncp->nc_name, cnp->cn_nameptr, (u_int)ncp->nc_nlen)) 153 break; 154 } 155 156 return ncp; 157 } 158 159 /* 160 * Look for a the name in the cache. We don't do this 161 * if the segment name is long, simply so the cache can avoid 162 * holding long names (which would either waste space, or 163 * add greatly to the complexity). 164 * 165 * Lookup is called with ni_dvp pointing to the directory to search, 166 * ni_ptr pointing to the name of the entry being sought, ni_namelen 167 * tells the length of the name, and ni_hash contains a hash of 168 * the name. If the lookup succeeds, the vnode is locked, stored in ni_vp 169 * and a status of zero is returned. If the locking fails for whatever 170 * reason, the vnode is unlocked and the error is returned to caller. 171 * If the lookup determines that the name does not exist (negative cacheing), 172 * a status of ENOENT is returned. If the lookup fails, a status of -1 173 * is returned. 174 */ 175 int 176 cache_lookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp) 177 { 178 struct namecache *ncp; 179 struct vnode *vp; 180 int error; 181 182 if (!doingcache) { 183 cnp->cn_flags &= ~MAKEENTRY; 184 *vpp = NULL; 185 return (-1); 186 } 187 188 if (cnp->cn_namelen > NCHNAMLEN) { 189 /* XXXSMP - updating stats without lock; do we care? */ 190 nchstats.ncs_long++; 191 cnp->cn_flags &= ~MAKEENTRY; 192 goto fail; 193 } 194 simple_lock(&namecache_slock); 195 ncp = cache_lookup_entry(dvp, cnp); 196 if (ncp == NULL) { 197 nchstats.ncs_miss++; 198 goto fail_wlock; 199 } 200 if ((cnp->cn_flags & MAKEENTRY) == 0) { 201 nchstats.ncs_badhits++; 202 goto remove; 203 } else if (ncp->nc_vp == NULL) { 204 /* 205 * Restore the ISWHITEOUT flag saved earlier. 206 */ 207 cnp->cn_flags |= ncp->nc_flags; 208 if (cnp->cn_nameiop != CREATE || 209 (cnp->cn_flags & ISLASTCN) == 0) { 210 nchstats.ncs_neghits++; 211 /* 212 * Move this slot to end of LRU chain, 213 * if not already there. 214 */ 215 if (TAILQ_NEXT(ncp, nc_lru) != 0) { 216 TAILQ_REMOVE(&nclruhead, ncp, nc_lru); 217 TAILQ_INSERT_TAIL(&nclruhead, ncp, nc_lru); 218 } 219 simple_unlock(&namecache_slock); 220 return (ENOENT); 221 } else { 222 nchstats.ncs_badhits++; 223 goto remove; 224 } 225 } 226 227 vp = ncp->nc_vp; 228 229 /* 230 * Move this slot to end of LRU chain, if not already there. 231 */ 232 if (TAILQ_NEXT(ncp, nc_lru) != 0) { 233 TAILQ_REMOVE(&nclruhead, ncp, nc_lru); 234 TAILQ_INSERT_TAIL(&nclruhead, ncp, nc_lru); 235 } 236 237 error = vget(vp, LK_NOWAIT); 238 239 /* Release the name cache mutex while we get reference to the vnode */ 240 simple_unlock(&namecache_slock); 241 242 #ifdef DEBUG 243 /* 244 * since we released namecache_slock, 245 * we can't use this pointer any more. 246 */ 247 ncp = NULL; 248 #endif /* DEBUG */ 249 250 if (error) { 251 KASSERT(error == EBUSY); 252 /* 253 * this vnode is being cleaned out. 254 */ 255 nchstats.ncs_falsehits++; /* XXX badhits? */ 256 goto fail; 257 } 258 259 if (vp == dvp) { /* lookup on "." */ 260 error = 0; 261 } else if (cnp->cn_flags & ISDOTDOT) { 262 VOP_UNLOCK(dvp, 0); 263 cnp->cn_flags |= PDIRUNLOCK; 264 error = vn_lock(vp, LK_EXCLUSIVE); 265 /* 266 * If the above vn_lock() succeeded and both LOCKPARENT and 267 * ISLASTCN is set, lock the directory vnode as well. 268 */ 269 if (!error && (~cnp->cn_flags & (LOCKPARENT|ISLASTCN)) == 0) { 270 if ((error = vn_lock(dvp, LK_EXCLUSIVE)) != 0) { 271 vput(vp); 272 return (error); 273 } 274 cnp->cn_flags &= ~PDIRUNLOCK; 275 } 276 } else { 277 error = vn_lock(vp, LK_EXCLUSIVE); 278 /* 279 * If the above vn_lock() failed or either of LOCKPARENT or 280 * ISLASTCN is set, unlock the directory vnode. 281 */ 282 if (error || (~cnp->cn_flags & (LOCKPARENT|ISLASTCN)) != 0) { 283 VOP_UNLOCK(dvp, 0); 284 cnp->cn_flags |= PDIRUNLOCK; 285 } 286 } 287 288 /* 289 * Check that the lock succeeded. 290 */ 291 if (error) { 292 /* XXXSMP - updating stats without lock; do we care? */ 293 nchstats.ncs_badhits++; 294 295 /* 296 * The parent needs to be locked when we return to VOP_LOOKUP(). 297 * The `.' case here should be extremely rare (if it can happen 298 * at all), so we don't bother optimizing out the unlock/relock. 299 */ 300 if ((error = vn_lock(dvp, LK_EXCLUSIVE)) != 0) 301 return (error); 302 cnp->cn_flags &= ~PDIRUNLOCK; 303 *vpp = NULL; 304 return (-1); 305 } 306 307 /* XXXSMP - updating stats without lock; do we care? */ 308 nchstats.ncs_goodhits++; 309 *vpp = vp; 310 return (0); 311 312 remove: 313 /* 314 * Last component and we are renaming or deleting, 315 * the cache entry is invalid, or otherwise don't 316 * want cache entry to exist. 317 */ 318 cache_remove(ncp); 319 cache_free(ncp); 320 321 fail_wlock: 322 simple_unlock(&namecache_slock); 323 fail: 324 *vpp = NULL; 325 return (-1); 326 } 327 328 int 329 cache_lookup_raw(struct vnode *dvp, struct vnode **vpp, 330 struct componentname *cnp) 331 { 332 struct namecache *ncp; 333 struct vnode *vp; 334 int error; 335 336 if (!doingcache) { 337 cnp->cn_flags &= ~MAKEENTRY; 338 *vpp = NULL; 339 return (-1); 340 } 341 342 if (cnp->cn_namelen > NCHNAMLEN) { 343 /* XXXSMP - updating stats without lock; do we care? */ 344 nchstats.ncs_long++; 345 cnp->cn_flags &= ~MAKEENTRY; 346 goto fail; 347 } 348 simple_lock(&namecache_slock); 349 ncp = cache_lookup_entry(dvp, cnp); 350 if (ncp == NULL) { 351 nchstats.ncs_miss++; 352 goto fail_wlock; 353 } 354 /* 355 * Move this slot to end of LRU chain, 356 * if not already there. 357 */ 358 if (TAILQ_NEXT(ncp, nc_lru) != 0) { 359 TAILQ_REMOVE(&nclruhead, ncp, nc_lru); 360 TAILQ_INSERT_TAIL(&nclruhead, ncp, nc_lru); 361 } 362 363 vp = ncp->nc_vp; 364 if (vp == NULL) { 365 /* 366 * Restore the ISWHITEOUT flag saved earlier. 367 */ 368 cnp->cn_flags |= ncp->nc_flags; 369 nchstats.ncs_neghits++; 370 simple_unlock(&namecache_slock); 371 return (ENOENT); 372 } 373 374 error = vget(vp, LK_NOWAIT); 375 376 /* Release the name cache mutex while we get reference to the vnode */ 377 simple_unlock(&namecache_slock); 378 379 if (error) { 380 KASSERT(error == EBUSY); 381 /* 382 * this vnode is being cleaned out. 383 */ 384 nchstats.ncs_falsehits++; /* XXX badhits? */ 385 goto fail; 386 } 387 388 *vpp = vp; 389 390 return 0; 391 392 fail_wlock: 393 simple_unlock(&namecache_slock); 394 fail: 395 *vpp = NULL; 396 return -1; 397 } 398 399 /* 400 * Scan cache looking for name of directory entry pointing at vp. 401 * 402 * Fill in dvpp. 403 * 404 * If bufp is non-NULL, also place the name in the buffer which starts 405 * at bufp, immediately before *bpp, and move bpp backwards to point 406 * at the start of it. (Yes, this is a little baroque, but it's done 407 * this way to cater to the whims of getcwd). 408 * 409 * Returns 0 on success, -1 on cache miss, positive errno on failure. 410 */ 411 int 412 cache_revlookup(struct vnode *vp, struct vnode **dvpp, char **bpp, char *bufp) 413 { 414 struct namecache *ncp; 415 struct vnode *dvp; 416 struct ncvhashhead *nvcpp; 417 char *bp; 418 419 if (!doingcache) 420 goto out; 421 422 nvcpp = &ncvhashtbl[NCVHASH(vp)]; 423 424 simple_lock(&namecache_slock); 425 LIST_FOREACH(ncp, nvcpp, nc_vhash) { 426 if (ncp->nc_vp == vp && 427 (dvp = ncp->nc_dvp) != NULL && 428 dvp != vp) { /* avoid pesky . entries.. */ 429 430 #ifdef DIAGNOSTIC 431 if (ncp->nc_nlen == 1 && 432 ncp->nc_name[0] == '.') 433 panic("cache_revlookup: found entry for ."); 434 435 if (ncp->nc_nlen == 2 && 436 ncp->nc_name[0] == '.' && 437 ncp->nc_name[1] == '.') 438 panic("cache_revlookup: found entry for .."); 439 #endif 440 nchstats.ncs_revhits++; 441 442 if (bufp) { 443 bp = *bpp; 444 bp -= ncp->nc_nlen; 445 if (bp <= bufp) { 446 *dvpp = NULL; 447 simple_unlock(&namecache_slock); 448 return (ERANGE); 449 } 450 memcpy(bp, ncp->nc_name, ncp->nc_nlen); 451 *bpp = bp; 452 } 453 454 /* XXX MP: how do we know dvp won't evaporate? */ 455 *dvpp = dvp; 456 simple_unlock(&namecache_slock); 457 return (0); 458 } 459 } 460 nchstats.ncs_revmiss++; 461 simple_unlock(&namecache_slock); 462 out: 463 *dvpp = NULL; 464 return (-1); 465 } 466 467 /* 468 * Add an entry to the cache 469 */ 470 void 471 cache_enter(struct vnode *dvp, struct vnode *vp, struct componentname *cnp) 472 { 473 struct namecache *ncp; 474 struct namecache *oncp; 475 struct nchashhead *ncpp; 476 struct ncvhashhead *nvcpp; 477 478 #ifdef DIAGNOSTIC 479 if (cnp->cn_namelen > NCHNAMLEN) 480 panic("cache_enter: name too long"); 481 #endif 482 if (!doingcache) 483 return; 484 /* 485 * Free the cache slot at head of lru chain. 486 */ 487 simple_lock(&namecache_slock); 488 489 if (numcache < numvnodes) { 490 numcache++; 491 simple_unlock(&namecache_slock); 492 ncp = pool_get(&namecache_pool, PR_WAITOK); 493 memset(ncp, 0, sizeof(*ncp)); 494 simple_lock(&namecache_slock); 495 } else if ((ncp = TAILQ_FIRST(&nclruhead)) != NULL) { 496 cache_remove(ncp); 497 } else { 498 simple_unlock(&namecache_slock); 499 return; 500 } 501 502 /* 503 * Concurrent lookups in the same directory may race for a 504 * cache entry. if there's a duplicated entry, free it. 505 */ 506 oncp = cache_lookup_entry(dvp, cnp); 507 if (oncp) { 508 cache_remove(oncp); 509 cache_free(oncp); 510 } 511 KASSERT(cache_lookup_entry(dvp, cnp) == NULL); 512 513 /* Grab the vnode we just found. */ 514 ncp->nc_vp = vp; 515 if (vp == NULL) { 516 /* 517 * For negative hits, save the ISWHITEOUT flag so we can 518 * restore it later when the cache entry is used again. 519 */ 520 ncp->nc_flags = cnp->cn_flags & ISWHITEOUT; 521 } 522 /* Fill in cache info. */ 523 ncp->nc_dvp = dvp; 524 LIST_INSERT_HEAD(&dvp->v_dnclist, ncp, nc_dvlist); 525 if (vp) 526 LIST_INSERT_HEAD(&vp->v_nclist, ncp, nc_vlist); 527 ncp->nc_nlen = cnp->cn_namelen; 528 memcpy(ncp->nc_name, cnp->cn_nameptr, (unsigned)ncp->nc_nlen); 529 TAILQ_INSERT_TAIL(&nclruhead, ncp, nc_lru); 530 ncpp = &nchashtbl[NCHASH(cnp, dvp)]; 531 LIST_INSERT_HEAD(ncpp, ncp, nc_hash); 532 533 ncp->nc_vhash.le_prev = NULL; 534 ncp->nc_vhash.le_next = NULL; 535 536 /* 537 * Create reverse-cache entries (used in getcwd) for directories. 538 */ 539 if (vp != NULL && 540 vp != dvp && 541 #ifndef NAMECACHE_ENTER_REVERSE 542 vp->v_type == VDIR && 543 #endif 544 (ncp->nc_nlen > 2 || 545 (ncp->nc_nlen > 1 && ncp->nc_name[1] != '.') || 546 (/* ncp->nc_nlen > 0 && */ ncp->nc_name[0] != '.'))) { 547 nvcpp = &ncvhashtbl[NCVHASH(vp)]; 548 LIST_INSERT_HEAD(nvcpp, ncp, nc_vhash); 549 } 550 simple_unlock(&namecache_slock); 551 } 552 553 /* 554 * Name cache initialization, from vfs_init() when we are booting 555 */ 556 void 557 nchinit(void) 558 { 559 560 TAILQ_INIT(&nclruhead); 561 nchashtbl = 562 hashinit(desiredvnodes, HASH_LIST, M_CACHE, M_WAITOK, &nchash); 563 ncvhashtbl = 564 #ifdef NAMECACHE_ENTER_REVERSE 565 hashinit(desiredvnodes, HASH_LIST, M_CACHE, M_WAITOK, &ncvhash); 566 #else 567 hashinit(desiredvnodes/8, HASH_LIST, M_CACHE, M_WAITOK, &ncvhash); 568 #endif 569 } 570 571 /* 572 * Name cache reinitialization, for when the maximum number of vnodes increases. 573 */ 574 void 575 nchreinit(void) 576 { 577 struct namecache *ncp; 578 struct nchashhead *oldhash1, *hash1; 579 struct ncvhashhead *oldhash2, *hash2; 580 u_long i, oldmask1, oldmask2, mask1, mask2; 581 582 hash1 = hashinit(desiredvnodes, HASH_LIST, M_CACHE, M_WAITOK, &mask1); 583 hash2 = 584 #ifdef NAMECACHE_ENTER_REVERSE 585 hashinit(desiredvnodes, HASH_LIST, M_CACHE, M_WAITOK, &mask2); 586 #else 587 hashinit(desiredvnodes/8, HASH_LIST, M_CACHE, M_WAITOK, &mask2); 588 #endif 589 simple_lock(&namecache_slock); 590 oldhash1 = nchashtbl; 591 oldmask1 = nchash; 592 nchashtbl = hash1; 593 nchash = mask1; 594 oldhash2 = ncvhashtbl; 595 oldmask2 = ncvhash; 596 ncvhashtbl = hash2; 597 ncvhash = mask2; 598 for (i = 0; i <= oldmask1; i++) { 599 while ((ncp = LIST_FIRST(&oldhash1[i])) != NULL) { 600 LIST_REMOVE(ncp, nc_hash); 601 ncp->nc_hash.le_prev = NULL; 602 } 603 } 604 for (i = 0; i <= oldmask2; i++) { 605 while ((ncp = LIST_FIRST(&oldhash2[i])) != NULL) { 606 LIST_REMOVE(ncp, nc_vhash); 607 ncp->nc_vhash.le_prev = NULL; 608 } 609 } 610 simple_unlock(&namecache_slock); 611 hashdone(oldhash1, M_CACHE); 612 hashdone(oldhash2, M_CACHE); 613 } 614 615 /* 616 * Cache flush, a particular vnode; called when a vnode is renamed to 617 * hide entries that would now be invalid 618 */ 619 void 620 cache_purge1(struct vnode *vp, const struct componentname *cnp, int flags) 621 { 622 struct namecache *ncp, *ncnext; 623 624 simple_lock(&namecache_slock); 625 if (flags & PURGE_PARENTS) { 626 for (ncp = LIST_FIRST(&vp->v_nclist); ncp != NULL; 627 ncp = ncnext) { 628 ncnext = LIST_NEXT(ncp, nc_vlist); 629 cache_remove(ncp); 630 cache_free(ncp); 631 } 632 } 633 if (flags & PURGE_CHILDREN) { 634 for (ncp = LIST_FIRST(&vp->v_dnclist); ncp != NULL; 635 ncp = ncnext) { 636 ncnext = LIST_NEXT(ncp, nc_dvlist); 637 cache_remove(ncp); 638 cache_free(ncp); 639 } 640 } 641 if (cnp != NULL) { 642 ncp = cache_lookup_entry(vp, cnp); 643 if (ncp) { 644 cache_remove(ncp); 645 cache_free(ncp); 646 } 647 } 648 simple_unlock(&namecache_slock); 649 } 650 651 /* 652 * Cache flush, a whole filesystem; called when filesys is umounted to 653 * remove entries that would now be invalid. 654 */ 655 void 656 cache_purgevfs(struct mount *mp) 657 { 658 struct namecache *ncp, *nxtcp; 659 660 simple_lock(&namecache_slock); 661 for (ncp = TAILQ_FIRST(&nclruhead); ncp != NULL; ncp = nxtcp) { 662 nxtcp = TAILQ_NEXT(ncp, nc_lru); 663 if (ncp->nc_dvp == NULL || ncp->nc_dvp->v_mount != mp) { 664 continue; 665 } 666 /* Free the resources we had. */ 667 cache_remove(ncp); 668 cache_free(ncp); 669 } 670 simple_unlock(&namecache_slock); 671 } 672 673 #ifdef DDB 674 void 675 namecache_print(struct vnode *vp, void (*pr)(const char *, ...)) 676 { 677 struct vnode *dvp = NULL; 678 struct namecache *ncp; 679 680 TAILQ_FOREACH(ncp, &nclruhead, nc_lru) { 681 if (ncp->nc_vp == vp) { 682 (*pr)("name %.*s\n", ncp->nc_nlen, ncp->nc_name); 683 dvp = ncp->nc_dvp; 684 } 685 } 686 if (dvp == NULL) { 687 (*pr)("name not found\n"); 688 return; 689 } 690 vp = dvp; 691 TAILQ_FOREACH(ncp, &nclruhead, nc_lru) { 692 if (ncp->nc_vp == vp) { 693 (*pr)("parent %.*s\n", ncp->nc_nlen, ncp->nc_name); 694 } 695 } 696 } 697 #endif 698