vfs_cache.c revision 65665
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 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)vfs_cache.c 8.5 (Berkeley) 3/22/95 37 * $FreeBSD: head/sys/kern/vfs_cache.c 65665 2000-09-10 03:46:12Z bp $ 38 */ 39 40#include <sys/param.h> 41#include <sys/systm.h> 42#include <sys/kernel.h> 43#include <sys/sysctl.h> 44#include <sys/mount.h> 45#include <sys/vnode.h> 46#include <sys/namei.h> 47#include <sys/malloc.h> 48#include <sys/sysproto.h> 49#include <sys/proc.h> 50#include <sys/filedesc.h> 51 52/* 53 * This structure describes the elements in the cache of recent 54 * names looked up by namei. 55 */ 56 57struct namecache { 58 LIST_ENTRY(namecache) nc_hash; /* hash chain */ 59 LIST_ENTRY(namecache) nc_src; /* source vnode list */ 60 TAILQ_ENTRY(namecache) nc_dst; /* destination vnode list */ 61 struct vnode *nc_dvp; /* vnode of parent of name */ 62 struct vnode *nc_vp; /* vnode the name refers to */ 63 u_char nc_flag; /* flag bits */ 64 u_char nc_nlen; /* length of name */ 65 char nc_name[0]; /* segment name */ 66}; 67 68/* 69 * Name caching works as follows: 70 * 71 * Names found by directory scans are retained in a cache 72 * for future reference. It is managed LRU, so frequently 73 * used names will hang around. Cache is indexed by hash value 74 * obtained from (vp, name) where vp refers to the directory 75 * containing name. 76 * 77 * If it is a "negative" entry, (i.e. for a name that is known NOT to 78 * exist) the vnode pointer will be NULL. 79 * 80 * Upon reaching the last segment of a path, if the reference 81 * is for DELETE, or NOCACHE is set (rewrite), and the 82 * name is located in the cache, it will be dropped. 83 */ 84 85/* 86 * Structures associated with name cacheing. 87 */ 88#define NCHHASH(dvp, hash) \ 89 (&nchashtbl[((dvp)->v_id + (hash)) & nchash]) 90static LIST_HEAD(nchashhead, namecache) *nchashtbl; /* Hash Table */ 91static TAILQ_HEAD(, namecache) ncneg; /* Hash Table */ 92static u_long nchash; /* size of hash table */ 93SYSCTL_ULONG(_debug, OID_AUTO, nchash, CTLFLAG_RD, &nchash, 0, ""); 94static u_long ncnegfactor = 16; /* ratio of negative entries */ 95SYSCTL_ULONG(_debug, OID_AUTO, ncnegfactor, CTLFLAG_RW, &ncnegfactor, 0, ""); 96static u_long numneg; /* number of cache entries allocated */ 97SYSCTL_ULONG(_debug, OID_AUTO, numneg, CTLFLAG_RD, &numneg, 0, ""); 98static u_long numcache; /* number of cache entries allocated */ 99SYSCTL_ULONG(_debug, OID_AUTO, numcache, CTLFLAG_RD, &numcache, 0, ""); 100struct nchstats nchstats; /* cache effectiveness statistics */ 101 102static int doingcache = 1; /* 1 => enable the cache */ 103SYSCTL_INT(_debug, OID_AUTO, vfscache, CTLFLAG_RW, &doingcache, 0, ""); 104SYSCTL_INT(_debug, OID_AUTO, vnsize, CTLFLAG_RD, 0, sizeof(struct vnode), ""); 105SYSCTL_INT(_debug, OID_AUTO, ncsize, CTLFLAG_RD, 0, sizeof(struct namecache), ""); 106 107/* 108 * The new name cache statistics 109 */ 110SYSCTL_NODE(_vfs, OID_AUTO, cache, CTLFLAG_RW, 0, "Name cache statistics"); 111#define STATNODE(mode, name, var) \ 112 SYSCTL_ULONG(_vfs_cache, OID_AUTO, name, mode, var, 0, ""); 113STATNODE(CTLFLAG_RD, numneg, &numneg); 114STATNODE(CTLFLAG_RD, numcache, &numcache); 115static u_long numcalls; STATNODE(CTLFLAG_RD, numcalls, &numcalls); 116static u_long dothits; STATNODE(CTLFLAG_RD, dothits, &dothits); 117static u_long dotdothits; STATNODE(CTLFLAG_RD, dotdothits, &dotdothits); 118static u_long numchecks; STATNODE(CTLFLAG_RD, numchecks, &numchecks); 119static u_long nummiss; STATNODE(CTLFLAG_RD, nummiss, &nummiss); 120static u_long nummisszap; STATNODE(CTLFLAG_RD, nummisszap, &nummisszap); 121static u_long numposzaps; STATNODE(CTLFLAG_RD, numposzaps, &numposzaps); 122static u_long numposhits; STATNODE(CTLFLAG_RD, numposhits, &numposhits); 123static u_long numnegzaps; STATNODE(CTLFLAG_RD, numnegzaps, &numnegzaps); 124static u_long numneghits; STATNODE(CTLFLAG_RD, numneghits, &numneghits); 125 126 127static void cache_zap __P((struct namecache *ncp)); 128 129MALLOC_DEFINE(M_VFSCACHE, "vfscache", "VFS name cache entries"); 130 131/* 132 * Flags in namecache.nc_flag 133 */ 134#define NCF_WHITE 1 135/* 136 * Delete an entry from its hash list and move it to the front 137 * of the LRU list for immediate reuse. 138 */ 139static void 140cache_zap(ncp) 141 struct namecache *ncp; 142{ 143 LIST_REMOVE(ncp, nc_hash); 144 LIST_REMOVE(ncp, nc_src); 145 if (LIST_EMPTY(&ncp->nc_dvp->v_cache_src)) 146 vdrop(ncp->nc_dvp); 147 if (ncp->nc_vp) { 148 TAILQ_REMOVE(&ncp->nc_vp->v_cache_dst, ncp, nc_dst); 149 } else { 150 TAILQ_REMOVE(&ncneg, ncp, nc_dst); 151 numneg--; 152 } 153 numcache--; 154 free(ncp, M_VFSCACHE); 155} 156 157/* 158 * Lookup an entry in the cache 159 * 160 * We don't do this if the segment name is long, simply so the cache 161 * can avoid holding long names (which would either waste space, or 162 * add greatly to the complexity). 163 * 164 * Lookup is called with dvp pointing to the directory to search, 165 * cnp pointing to the name of the entry being sought. If the lookup 166 * succeeds, the vnode is returned in *vpp, and a status of -1 is 167 * returned. If the lookup determines that the name does not exist 168 * (negative cacheing), a status of ENOENT is returned. If the lookup 169 * fails, a status of zero is returned. 170 */ 171 172int 173cache_lookup(dvp, vpp, cnp) 174 struct vnode *dvp; 175 struct vnode **vpp; 176 struct componentname *cnp; 177{ 178 struct namecache *ncp; 179 u_long hash; 180 u_char *cp; 181 int len; 182 183 if (!doingcache) { 184 cnp->cn_flags &= ~MAKEENTRY; 185 return (0); 186 } 187 188 numcalls++; 189 190 if (cnp->cn_nameptr[0] == '.') { 191 if (cnp->cn_namelen == 1) { 192 *vpp = dvp; 193 dothits++; 194 return (-1); 195 } 196 if (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.') { 197 dotdothits++; 198 if (dvp->v_dd->v_id != dvp->v_ddid || 199 (cnp->cn_flags & MAKEENTRY) == 0) { 200 dvp->v_ddid = 0; 201 return (0); 202 } 203 *vpp = dvp->v_dd; 204 return (-1); 205 } 206 } 207 208 hash = 0; 209 len = cnp->cn_namelen; 210 for (cp = cnp->cn_nameptr; len; len--, cp++) 211 hash += *cp; 212 LIST_FOREACH(ncp, (NCHHASH(dvp, hash)), nc_hash) { 213 numchecks++; 214 if (ncp->nc_dvp == dvp && ncp->nc_nlen == cnp->cn_namelen && 215 !bcmp(ncp->nc_name, cnp->cn_nameptr, ncp->nc_nlen)) 216 break; 217 } 218 219 /* We failed to find an entry */ 220 if (ncp == 0) { 221 if ((cnp->cn_flags & MAKEENTRY) == 0) { 222 nummisszap++; 223 } else { 224 nummiss++; 225 } 226 nchstats.ncs_miss++; 227 return (0); 228 } 229 230 /* We don't want to have an entry, so dump it */ 231 if ((cnp->cn_flags & MAKEENTRY) == 0) { 232 numposzaps++; 233 nchstats.ncs_badhits++; 234 cache_zap(ncp); 235 return (0); 236 } 237 238 /* We found a "positive" match, return the vnode */ 239 if (ncp->nc_vp) { 240 numposhits++; 241 nchstats.ncs_goodhits++; 242 *vpp = ncp->nc_vp; 243 return (-1); 244 } 245 246 /* We found a negative match, and want to create it, so purge */ 247 if (cnp->cn_nameiop == CREATE) { 248 numnegzaps++; 249 nchstats.ncs_badhits++; 250 cache_zap(ncp); 251 return (0); 252 } 253 254 numneghits++; 255 /* 256 * We found a "negative" match, ENOENT notifies client of this match. 257 * The nc_vpid field records whether this is a whiteout. 258 */ 259 TAILQ_REMOVE(&ncneg, ncp, nc_dst); 260 TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst); 261 nchstats.ncs_neghits++; 262 if (ncp->nc_flag & NCF_WHITE) 263 cnp->cn_flags |= ISWHITEOUT; 264 return (ENOENT); 265} 266 267/* 268 * Add an entry to the cache. 269 */ 270void 271cache_enter(dvp, vp, cnp) 272 struct vnode *dvp; 273 struct vnode *vp; 274 struct componentname *cnp; 275{ 276 struct namecache *ncp; 277 struct nchashhead *ncpp; 278 u_long hash; 279 u_char *cp, *dp; 280 int len; 281 282 if (!doingcache) 283 return; 284 285 if (cnp->cn_nameptr[0] == '.') { 286 if (cnp->cn_namelen == 1) { 287 return; 288 } 289 if (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.') { 290 if (vp) { 291 dvp->v_dd = vp; 292 dvp->v_ddid = vp->v_id; 293 } else { 294 dvp->v_dd = dvp; 295 dvp->v_ddid = 0; 296 } 297 return; 298 } 299 } 300 301 ncp = (struct namecache *) 302 malloc(sizeof *ncp + cnp->cn_namelen, M_VFSCACHE, M_WAITOK); 303 bzero((char *)ncp, sizeof *ncp); 304 numcache++; 305 if (!vp) { 306 numneg++; 307 ncp->nc_flag = cnp->cn_flags & ISWHITEOUT ? NCF_WHITE : 0; 308 } else if (vp->v_type == VDIR) { 309 vp->v_dd = dvp; 310 vp->v_ddid = dvp->v_id; 311 } 312 313 /* 314 * Fill in cache info, if vp is NULL this is a "negative" cache entry. 315 * For negative entries, we have to record whether it is a whiteout. 316 * the whiteout flag is stored in the nc_vpid field which is 317 * otherwise unused. 318 */ 319 ncp->nc_vp = vp; 320 ncp->nc_dvp = dvp; 321 len = ncp->nc_nlen = cnp->cn_namelen; 322 hash = 0; 323 dp = ncp->nc_name; 324 for (cp = cnp->cn_nameptr; len; len--, cp++, dp++) 325 hash += (*dp = *cp); 326 ncpp = NCHHASH(dvp, hash); 327 LIST_INSERT_HEAD(ncpp, ncp, nc_hash); 328 if (LIST_EMPTY(&dvp->v_cache_src)) 329 vhold(dvp); 330 LIST_INSERT_HEAD(&dvp->v_cache_src, ncp, nc_src); 331 if (vp) { 332 TAILQ_INSERT_HEAD(&vp->v_cache_dst, ncp, nc_dst); 333 } else { 334 TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst); 335 } 336 if (numneg * ncnegfactor > numcache) { 337 ncp = TAILQ_FIRST(&ncneg); 338 cache_zap(ncp); 339 } 340} 341 342/* 343 * Name cache initialization, from vfs_init() when we are booting 344 */ 345void 346nchinit() 347{ 348 349 TAILQ_INIT(&ncneg); 350 nchashtbl = hashinit(desiredvnodes*2, M_VFSCACHE, &nchash); 351} 352 353/* 354 * Invalidate all entries to a particular vnode. 355 * 356 * Remove all entries in the namecache relating to this vnode and 357 * change the v_id. We take the v_id from a global counter, since 358 * it becomes a handy sequence number in crash-dumps that way. 359 * No valid vnode will ever have (v_id == 0). 360 * 361 * XXX: Only time and the size of v_id prevents this from failing: 362 * XXX: In theory we should hunt down all (struct vnode*, v_id) 363 * XXX: soft references and nuke them, at least on the global 364 * XXX: v_id wraparound. The period of resistance can be extended 365 * XXX: by incrementing each vnodes v_id individually instead of 366 * XXX: using the global v_id. 367 */ 368 369void 370cache_purge(vp) 371 struct vnode *vp; 372{ 373 static u_long nextid; 374 375 while (!LIST_EMPTY(&vp->v_cache_src)) 376 cache_zap(LIST_FIRST(&vp->v_cache_src)); 377 while (!TAILQ_EMPTY(&vp->v_cache_dst)) 378 cache_zap(TAILQ_FIRST(&vp->v_cache_dst)); 379 380 do 381 nextid++; 382 while (nextid == vp->v_id || !nextid); 383 vp->v_id = nextid; 384 vp->v_dd = vp; 385 vp->v_ddid = 0; 386} 387 388/* 389 * Flush all entries referencing a particular filesystem. 390 * 391 * Since we need to check it anyway, we will flush all the invalid 392 * entries at the same time. 393 */ 394void 395cache_purgevfs(mp) 396 struct mount *mp; 397{ 398 struct nchashhead *ncpp; 399 struct namecache *ncp, *nnp; 400 401 /* Scan hash tables for applicable entries */ 402 for (ncpp = &nchashtbl[nchash]; ncpp >= nchashtbl; ncpp--) { 403 for (ncp = LIST_FIRST(ncpp); ncp != 0; ncp = nnp) { 404 nnp = LIST_NEXT(ncp, nc_hash); 405 if (ncp->nc_dvp->v_mount == mp) { 406 cache_zap(ncp); 407 } 408 } 409 } 410} 411 412/* 413 * Perform canonical checks and cache lookup and pass on to filesystem 414 * through the vop_cachedlookup only if needed. 415 */ 416 417int 418vfs_cache_lookup(ap) 419 struct vop_lookup_args /* { 420 struct vnode *a_dvp; 421 struct vnode **a_vpp; 422 struct componentname *a_cnp; 423 } */ *ap; 424{ 425 struct vnode *dvp, *vp; 426 int lockparent; 427 int error; 428 struct vnode **vpp = ap->a_vpp; 429 struct componentname *cnp = ap->a_cnp; 430 struct ucred *cred = cnp->cn_cred; 431 int flags = cnp->cn_flags; 432 struct proc *p = cnp->cn_proc; 433 u_long vpid; /* capability number of vnode */ 434 435 *vpp = NULL; 436 dvp = ap->a_dvp; 437 lockparent = flags & LOCKPARENT; 438 439 if (dvp->v_type != VDIR) 440 return (ENOTDIR); 441 442 if ((flags & ISLASTCN) && (dvp->v_mount->mnt_flag & MNT_RDONLY) && 443 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) 444 return (EROFS); 445 446 error = VOP_ACCESS(dvp, VEXEC, cred, p); 447 448 if (error) 449 return (error); 450 451 error = cache_lookup(dvp, vpp, cnp); 452 453 if (!error) 454 return (VOP_CACHEDLOOKUP(dvp, vpp, cnp)); 455 456 if (error == ENOENT) 457 return (error); 458 459 vp = *vpp; 460 vpid = vp->v_id; 461 if (dvp == vp) { /* lookup on "." */ 462 VREF(vp); 463 error = 0; 464 } else if (flags & ISDOTDOT) { 465 VOP_UNLOCK(dvp, 0, p); 466 error = vget(vp, LK_EXCLUSIVE, p); 467 if (!error && lockparent && (flags & ISLASTCN)) 468 error = vn_lock(dvp, LK_EXCLUSIVE, p); 469 } else { 470 error = vget(vp, LK_EXCLUSIVE, p); 471 if (!lockparent || error || !(flags & ISLASTCN)) 472 VOP_UNLOCK(dvp, 0, p); 473 } 474 /* 475 * Check that the capability number did not change 476 * while we were waiting for the lock. 477 */ 478 if (!error) { 479 if (vpid == vp->v_id) 480 return (0); 481 vput(vp); 482 if (lockparent && dvp != vp && (flags & ISLASTCN)) 483 VOP_UNLOCK(dvp, 0, p); 484 } 485 error = vn_lock(dvp, LK_EXCLUSIVE, p); 486 if (error) 487 return (error); 488 return (VOP_CACHEDLOOKUP(dvp, vpp, cnp)); 489} 490 491 492#ifndef _SYS_SYSPROTO_H_ 493struct __getcwd_args { 494 u_char *buf; 495 u_int buflen; 496}; 497#endif 498 499static int disablecwd; 500SYSCTL_INT(_debug, OID_AUTO, disablecwd, CTLFLAG_RW, &disablecwd, 0, ""); 501 502static u_long numcwdcalls; STATNODE(CTLFLAG_RD, numcwdcalls, &numcwdcalls); 503static u_long numcwdfail1; STATNODE(CTLFLAG_RD, numcwdfail1, &numcwdfail1); 504static u_long numcwdfail2; STATNODE(CTLFLAG_RD, numcwdfail2, &numcwdfail2); 505static u_long numcwdfail3; STATNODE(CTLFLAG_RD, numcwdfail3, &numcwdfail3); 506static u_long numcwdfail4; STATNODE(CTLFLAG_RD, numcwdfail4, &numcwdfail4); 507static u_long numcwdfound; STATNODE(CTLFLAG_RD, numcwdfound, &numcwdfound); 508int 509__getcwd(p, uap) 510 struct proc *p; 511 struct __getcwd_args *uap; 512{ 513 char *bp, *buf; 514 int error, i, slash_prefixed; 515 struct filedesc *fdp; 516 struct namecache *ncp; 517 struct vnode *vp; 518 519 numcwdcalls++; 520 if (disablecwd) 521 return (ENODEV); 522 if (uap->buflen < 2) 523 return (EINVAL); 524 if (uap->buflen > MAXPATHLEN) 525 uap->buflen = MAXPATHLEN; 526 buf = bp = malloc(uap->buflen, M_TEMP, M_WAITOK); 527 bp += uap->buflen - 1; 528 *bp = '\0'; 529 fdp = p->p_fd; 530 slash_prefixed = 0; 531 for (vp = fdp->fd_cdir; vp != fdp->fd_rdir && vp != rootvnode;) { 532 if (vp->v_flag & VROOT) { 533 if (vp->v_mount == NULL) /* forced unmount */ 534 return (EBADF); 535 vp = vp->v_mount->mnt_vnodecovered; 536 continue; 537 } 538 if (vp->v_dd->v_id != vp->v_ddid) { 539 numcwdfail1++; 540 free(buf, M_TEMP); 541 return (ENOTDIR); 542 } 543 ncp = TAILQ_FIRST(&vp->v_cache_dst); 544 if (!ncp) { 545 numcwdfail2++; 546 free(buf, M_TEMP); 547 return (ENOENT); 548 } 549 if (ncp->nc_dvp != vp->v_dd) { 550 numcwdfail3++; 551 free(buf, M_TEMP); 552 return (EBADF); 553 } 554 for (i = ncp->nc_nlen - 1; i >= 0; i--) { 555 if (bp == buf) { 556 numcwdfail4++; 557 free(buf, M_TEMP); 558 return (ENOMEM); 559 } 560 *--bp = ncp->nc_name[i]; 561 } 562 if (bp == buf) { 563 numcwdfail4++; 564 free(buf, M_TEMP); 565 return (ENOMEM); 566 } 567 *--bp = '/'; 568 slash_prefixed = 1; 569 vp = vp->v_dd; 570 } 571 if (!slash_prefixed) { 572 if (bp == buf) { 573 numcwdfail4++; 574 free(buf, M_TEMP); 575 return (ENOMEM); 576 } 577 *--bp = '/'; 578 } 579 numcwdfound++; 580 error = copyout(bp, uap->buf, strlen(bp) + 1); 581 free(buf, M_TEMP); 582 return (error); 583} 584 585/* 586 * Thus begins the fullpath magic. 587 */ 588 589#undef STATNODE 590#define STATNODE(name) \ 591 static u_int name; \ 592 SYSCTL_UINT(_vfs_cache, OID_AUTO, name, CTLFLAG_RD, &name, 0, "") 593 594static int disablefullpath; 595SYSCTL_INT(_debug, OID_AUTO, disablefullpath, CTLFLAG_RW, 596 &disablefullpath, 0, ""); 597 598STATNODE(numfullpathcalls); 599STATNODE(numfullpathfail1); 600STATNODE(numfullpathfail2); 601STATNODE(numfullpathfail3); 602STATNODE(numfullpathfail4); 603STATNODE(numfullpathfound); 604 605int 606textvp_fullpath(struct proc *p, char **retbuf, char **retfreebuf) { 607 char *bp, *buf; 608 int i, slash_prefixed; 609 struct filedesc *fdp; 610 struct namecache *ncp; 611 struct vnode *vp, *textvp; 612 613 numfullpathcalls++; 614 if (disablefullpath) 615 return (ENODEV); 616 textvp = p->p_textvp; 617 if (textvp == NULL) 618 return (EINVAL); 619 buf = malloc(MAXPATHLEN, M_TEMP, M_WAITOK); 620 bp = buf + MAXPATHLEN - 1; 621 *bp = '\0'; 622 fdp = p->p_fd; 623 slash_prefixed = 0; 624 for (vp = textvp; vp != fdp->fd_rdir && vp != rootvnode;) { 625 if (vp->v_flag & VROOT) { 626 if (vp->v_mount == NULL) { /* forced unmount */ 627 free(buf, M_TEMP); 628 return (EBADF); 629 } 630 vp = vp->v_mount->mnt_vnodecovered; 631 continue; 632 } 633 if (vp != textvp && vp->v_dd->v_id != vp->v_ddid) { 634 numfullpathfail1++; 635 free(buf, M_TEMP); 636 return (ENOTDIR); 637 } 638 ncp = TAILQ_FIRST(&vp->v_cache_dst); 639 if (!ncp) { 640 numfullpathfail2++; 641 free(buf, M_TEMP); 642 return (ENOENT); 643 } 644 if (vp != textvp && ncp->nc_dvp != vp->v_dd) { 645 numfullpathfail3++; 646 free(buf, M_TEMP); 647 return (EBADF); 648 } 649 for (i = ncp->nc_nlen - 1; i >= 0; i--) { 650 if (bp == buf) { 651 numfullpathfail4++; 652 free(buf, M_TEMP); 653 return (ENOMEM); 654 } 655 *--bp = ncp->nc_name[i]; 656 } 657 if (bp == buf) { 658 numfullpathfail4++; 659 free(buf, M_TEMP); 660 return (ENOMEM); 661 } 662 *--bp = '/'; 663 slash_prefixed = 1; 664 vp = ncp->nc_dvp; 665 } 666 if (!slash_prefixed) { 667 if (bp == buf) { 668 numfullpathfail4++; 669 free(buf, M_TEMP); 670 return (ENOMEM); 671 } 672 *--bp = '/'; 673 } 674 numfullpathfound++; 675 *retbuf = bp; 676 *retfreebuf = buf; 677 return (0); 678} 679