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sys/ufs/ufs/ufs_lookup.c
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1 /*- 2 * Copyright (c) 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)ufs_lookup.c 8.15 (Berkeley) 6/16/95 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD: releng/8.4/sys/ufs/ufs/ufs_lookup.c 246377 2013-02-06 03:00:18Z pfg $"); 39 40 #include "opt_ufs.h" 41 #include "opt_quota.h" 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/kernel.h> 46 #include <sys/namei.h> 47 #include <sys/bio.h> 48 #include <sys/buf.h> 49 #include <sys/proc.h> 50 #include <sys/stat.h> 51 #include <sys/mount.h> 52 #include <sys/vnode.h> 53 #include <sys/sysctl.h> 54 55 #include <vm/vm.h> 56 #include <vm/vm_extern.h> 57 58 #include <ufs/ufs/extattr.h> 59 #include <ufs/ufs/quota.h> 60 #include <ufs/ufs/inode.h> 61 #include <ufs/ufs/dir.h> 62 #ifdef UFS_DIRHASH 63 #include <ufs/ufs/dirhash.h> 64 #endif 65 #include <ufs/ufs/ufsmount.h> 66 #include <ufs/ufs/ufs_extern.h> 67 68 #ifdef DIAGNOSTIC 69 static int dirchk = 1; 70 #else 71 static int dirchk = 0; 72 #endif 73 74 SYSCTL_INT(_debug, OID_AUTO, dircheck, CTLFLAG_RW, &dirchk, 0, ""); 75 76 /* true if old FS format...*/ 77 #define OFSFMT(vp) ((vp)->v_mount->mnt_maxsymlinklen <= 0) 78 79 #ifdef QUOTA 80 static int 81 ufs_lookup_upgrade_lock(struct vnode *vp) 82 { 83 int error; 84 85 ASSERT_VOP_LOCKED(vp, __FUNCTION__); 86 if (VOP_ISLOCKED(vp) == LK_EXCLUSIVE) 87 return (0); 88 89 error = 0; 90 91 /* 92 * Upgrade vnode lock, since getinoquota() 93 * requires exclusive lock to modify inode. 94 */ 95 vhold(vp); 96 vn_lock(vp, LK_UPGRADE | LK_RETRY); 97 VI_LOCK(vp); 98 if (vp->v_iflag & VI_DOOMED) 99 error = ENOENT; 100 vdropl(vp); 101 return (error); 102 } 103 #endif 104 105 static int 106 ufs_delete_denied(struct vnode *vdp, struct vnode *tdp, struct ucred *cred, 107 struct thread *td) 108 { 109 int error; 110 111 #ifdef UFS_ACL 112 /* 113 * NFSv4 Minor Version 1, draft-ietf-nfsv4-minorversion1-03.txt 114 * 115 * 3.16.2.1. ACE4_DELETE vs. ACE4_DELETE_CHILD 116 */ 117 118 /* 119 * XXX: Is this check required? 120 */ 121 error = VOP_ACCESS(vdp, VEXEC, cred, td); 122 if (error) 123 return (error); 124 125 error = VOP_ACCESSX(tdp, VDELETE, cred, td); 126 if (error == 0) 127 return (0); 128 129 error = VOP_ACCESSX(vdp, VDELETE_CHILD, cred, td); 130 if (error == 0) 131 return (0); 132 133 error = VOP_ACCESSX(vdp, VEXPLICIT_DENY | VDELETE_CHILD, cred, td); 134 if (error) 135 return (error); 136 137 #endif /* !UFS_ACL */ 138 139 /* 140 * Standard Unix access control - delete access requires VWRITE. 141 */ 142 error = VOP_ACCESS(vdp, VWRITE, cred, td); 143 if (error) 144 return (error); 145 146 /* 147 * If directory is "sticky", then user must own 148 * the directory, or the file in it, else she 149 * may not delete it (unless she's root). This 150 * implements append-only directories. 151 */ 152 if ((VTOI(vdp)->i_mode & ISVTX) && 153 VOP_ACCESS(vdp, VADMIN, cred, td) && 154 VOP_ACCESS(tdp, VADMIN, cred, td)) 155 return (EPERM); 156 157 return (0); 158 } 159 160 /* 161 * Convert a component of a pathname into a pointer to a locked inode. 162 * This is a very central and rather complicated routine. 163 * If the filesystem is not maintained in a strict tree hierarchy, 164 * this can result in a deadlock situation (see comments in code below). 165 * 166 * The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending 167 * on whether the name is to be looked up, created, renamed, or deleted. 168 * When CREATE, RENAME, or DELETE is specified, information usable in 169 * creating, renaming, or deleting a directory entry may be calculated. 170 * If flag has LOCKPARENT or'ed into it and the target of the pathname 171 * exists, lookup returns both the target and its parent directory locked. 172 * When creating or renaming and LOCKPARENT is specified, the target may 173 * not be ".". When deleting and LOCKPARENT is specified, the target may 174 * be "."., but the caller must check to ensure it does an vrele and vput 175 * instead of two vputs. 176 * 177 * This routine is actually used as VOP_CACHEDLOOKUP method, and the 178 * filesystem employs the generic vfs_cache_lookup() as VOP_LOOKUP 179 * method. 180 * 181 * vfs_cache_lookup() performs the following for us: 182 * check that it is a directory 183 * check accessibility of directory 184 * check for modification attempts on read-only mounts 185 * if name found in cache 186 * if at end of path and deleting or creating 187 * drop it 188 * else 189 * return name. 190 * return VOP_CACHEDLOOKUP() 191 * 192 * Overall outline of ufs_lookup: 193 * 194 * search for name in directory, to found or notfound 195 * notfound: 196 * if creating, return locked directory, leaving info on available slots 197 * else return error 198 * found: 199 * if at end of path and deleting, return information to allow delete 200 * if at end of path and rewriting (RENAME and LOCKPARENT), lock target 201 * inode and return info to allow rewrite 202 * if not at end, add name to cache; if at end and neither creating 203 * nor deleting, add name to cache 204 */ 205 int 206 ufs_lookup(ap) 207 struct vop_cachedlookup_args /* { 208 struct vnode *a_dvp; 209 struct vnode **a_vpp; 210 struct componentname *a_cnp; 211 } */ *ap; 212 { 213 214 return (ufs_lookup_ino(ap->a_dvp, ap->a_vpp, ap->a_cnp, NULL)); 215 } 216 217 int 218 ufs_lookup_ino(struct vnode *vdp, struct vnode **vpp, struct componentname *cnp, 219 ino_t *dd_ino) 220 { 221 struct inode *dp; /* inode for directory being searched */ 222 struct buf *bp; /* a buffer of directory entries */ 223 struct direct *ep; /* the current directory entry */ 224 int entryoffsetinblock; /* offset of ep in bp's buffer */ 225 enum {NONE, COMPACT, FOUND} slotstatus; 226 doff_t slotoffset; /* offset of area with free space */ 227 doff_t i_diroff; /* cached i_diroff value. */ 228 doff_t i_offset; /* cached i_offset value. */ 229 int slotsize; /* size of area at slotoffset */ 230 int slotfreespace; /* amount of space free in slot */ 231 int slotneeded; /* size of the entry we're seeking */ 232 int numdirpasses; /* strategy for directory search */ 233 doff_t endsearch; /* offset to end directory search */ 234 doff_t prevoff; /* prev entry dp->i_offset */ 235 struct vnode *pdp; /* saved dp during symlink work */ 236 struct vnode *tdp; /* returned by VFS_VGET */ 237 doff_t enduseful; /* pointer past last used dir slot */ 238 u_long bmask; /* block offset mask */ 239 int namlen, error; 240 struct ucred *cred = cnp->cn_cred; 241 int flags = cnp->cn_flags; 242 int nameiop = cnp->cn_nameiop; 243 ino_t ino, ino1; 244 int ltype; 245 246 if (vpp != NULL) 247 *vpp = NULL; 248 249 dp = VTOI(vdp); 250 251 /* 252 * Create a vm object if vmiodirenable is enabled. 253 * Alternatively we could call vnode_create_vobject 254 * in VFS_VGET but we could end up creating objects 255 * that are never used. 256 */ 257 vnode_create_vobject(vdp, DIP(dp, i_size), cnp->cn_thread); 258 259 bmask = VFSTOUFS(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1; 260 #ifdef QUOTA 261 if ((nameiop == DELETE || nameiop == RENAME) && (flags & ISLASTCN)) { 262 error = ufs_lookup_upgrade_lock(vdp); 263 if (error != 0) 264 return (error); 265 } 266 #endif 267 268 restart: 269 bp = NULL; 270 slotoffset = -1; 271 272 /* 273 * We now have a segment name to search for, and a directory to search. 274 * 275 * Suppress search for slots unless creating 276 * file and at end of pathname, in which case 277 * we watch for a place to put the new file in 278 * case it doesn't already exist. 279 */ 280 ino = 0; 281 i_diroff = dp->i_diroff; 282 slotstatus = FOUND; 283 slotfreespace = slotsize = slotneeded = 0; 284 if ((nameiop == CREATE || nameiop == RENAME) && 285 (flags & ISLASTCN)) { 286 slotstatus = NONE; 287 slotneeded = DIRECTSIZ(cnp->cn_namelen); 288 } 289 290 #ifdef UFS_DIRHASH 291 /* 292 * Use dirhash for fast operations on large directories. The logic 293 * to determine whether to hash the directory is contained within 294 * ufsdirhash_build(); a zero return means that it decided to hash 295 * this directory and it successfully built up the hash table. 296 */ 297 if (ufsdirhash_build(dp) == 0) { 298 /* Look for a free slot if needed. */ 299 enduseful = dp->i_size; 300 if (slotstatus != FOUND) { 301 slotoffset = ufsdirhash_findfree(dp, slotneeded, 302 &slotsize); 303 if (slotoffset >= 0) { 304 slotstatus = COMPACT; 305 enduseful = ufsdirhash_enduseful(dp); 306 if (enduseful < 0) 307 enduseful = dp->i_size; 308 } 309 } 310 /* Look up the component. */ 311 numdirpasses = 1; 312 entryoffsetinblock = 0; /* silence compiler warning */ 313 switch (ufsdirhash_lookup(dp, cnp->cn_nameptr, cnp->cn_namelen, 314 &i_offset, &bp, nameiop == DELETE ? &prevoff : NULL)) { 315 case 0: 316 ep = (struct direct *)((char *)bp->b_data + 317 (i_offset & bmask)); 318 goto foundentry; 319 case ENOENT: 320 i_offset = roundup2(dp->i_size, DIRBLKSIZ); 321 goto notfound; 322 default: 323 /* Something failed; just do a linear search. */ 324 break; 325 } 326 } 327 #endif /* UFS_DIRHASH */ 328 /* 329 * If there is cached information on a previous search of 330 * this directory, pick up where we last left off. 331 * We cache only lookups as these are the most common 332 * and have the greatest payoff. Caching CREATE has little 333 * benefit as it usually must search the entire directory 334 * to determine that the entry does not exist. Caching the 335 * location of the last DELETE or RENAME has not reduced 336 * profiling time and hence has been removed in the interest 337 * of simplicity. 338 */ 339 if (nameiop != LOOKUP || i_diroff == 0 || i_diroff >= dp->i_size) { 340 entryoffsetinblock = 0; 341 i_offset = 0; 342 numdirpasses = 1; 343 } else { 344 i_offset = i_diroff; 345 if ((entryoffsetinblock = i_offset & bmask) && 346 (error = UFS_BLKATOFF(vdp, (off_t)i_offset, NULL, &bp))) 347 return (error); 348 numdirpasses = 2; 349 nchstats.ncs_2passes++; 350 } 351 prevoff = i_offset; 352 endsearch = roundup2(dp->i_size, DIRBLKSIZ); 353 enduseful = 0; 354 355 searchloop: 356 while (i_offset < endsearch) { 357 /* 358 * If necessary, get the next directory block. 359 */ 360 if ((i_offset & bmask) == 0) { 361 if (bp != NULL) 362 brelse(bp); 363 error = 364 UFS_BLKATOFF(vdp, (off_t)i_offset, NULL, &bp); 365 if (error) 366 return (error); 367 entryoffsetinblock = 0; 368 } 369 /* 370 * If still looking for a slot, and at a DIRBLKSIZE 371 * boundary, have to start looking for free space again. 372 */ 373 if (slotstatus == NONE && 374 (entryoffsetinblock & (DIRBLKSIZ - 1)) == 0) { 375 slotoffset = -1; 376 slotfreespace = 0; 377 } 378 /* 379 * Get pointer to next entry. 380 * Full validation checks are slow, so we only check 381 * enough to insure forward progress through the 382 * directory. Complete checks can be run by patching 383 * "dirchk" to be true. 384 */ 385 ep = (struct direct *)((char *)bp->b_data + entryoffsetinblock); 386 if (ep->d_reclen == 0 || ep->d_reclen > 387 DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1)) || 388 (dirchk && ufs_dirbadentry(vdp, ep, entryoffsetinblock))) { 389 int i; 390 391 ufs_dirbad(dp, i_offset, "mangled entry"); 392 i = DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1)); 393 i_offset += i; 394 entryoffsetinblock += i; 395 continue; 396 } 397 398 /* 399 * If an appropriate sized slot has not yet been found, 400 * check to see if one is available. Also accumulate space 401 * in the current block so that we can determine if 402 * compaction is viable. 403 */ 404 if (slotstatus != FOUND) { 405 int size = ep->d_reclen; 406 407 if (ep->d_ino != 0) 408 size -= DIRSIZ(OFSFMT(vdp), ep); 409 if (size > 0) { 410 if (size >= slotneeded) { 411 slotstatus = FOUND; 412 slotoffset = i_offset; 413 slotsize = ep->d_reclen; 414 } else if (slotstatus == NONE) { 415 slotfreespace += size; 416 if (slotoffset == -1) 417 slotoffset = i_offset; 418 if (slotfreespace >= slotneeded) { 419 slotstatus = COMPACT; 420 slotsize = i_offset + 421 ep->d_reclen - slotoffset; 422 } 423 } 424 } 425 } 426 427 /* 428 * Check for a name match. 429 */ 430 if (ep->d_ino) { 431 # if (BYTE_ORDER == LITTLE_ENDIAN) 432 if (OFSFMT(vdp)) 433 namlen = ep->d_type; 434 else 435 namlen = ep->d_namlen; 436 # else 437 namlen = ep->d_namlen; 438 # endif 439 if (namlen == cnp->cn_namelen && 440 (cnp->cn_nameptr[0] == ep->d_name[0]) && 441 !bcmp(cnp->cn_nameptr, ep->d_name, 442 (unsigned)namlen)) { 443 #ifdef UFS_DIRHASH 444 foundentry: 445 #endif 446 /* 447 * Save directory entry's inode number and 448 * reclen in ndp->ni_ufs area, and release 449 * directory buffer. 450 */ 451 if (vdp->v_mount->mnt_maxsymlinklen > 0 && 452 ep->d_type == DT_WHT) { 453 slotstatus = FOUND; 454 slotoffset = i_offset; 455 slotsize = ep->d_reclen; 456 enduseful = dp->i_size; 457 cnp->cn_flags |= ISWHITEOUT; 458 numdirpasses--; 459 goto notfound; 460 } 461 ino = ep->d_ino; 462 goto found; 463 } 464 } 465 prevoff = i_offset; 466 i_offset += ep->d_reclen; 467 entryoffsetinblock += ep->d_reclen; 468 if (ep->d_ino) 469 enduseful = i_offset; 470 } 471 notfound: 472 /* 473 * If we started in the middle of the directory and failed 474 * to find our target, we must check the beginning as well. 475 */ 476 if (numdirpasses == 2) { 477 numdirpasses--; 478 i_offset = 0; 479 endsearch = i_diroff; 480 goto searchloop; 481 } 482 if (bp != NULL) 483 brelse(bp); 484 /* 485 * If creating, and at end of pathname and current 486 * directory has not been removed, then can consider 487 * allowing file to be created. 488 */ 489 if ((nameiop == CREATE || nameiop == RENAME || 490 (nameiop == DELETE && 491 (cnp->cn_flags & DOWHITEOUT) && 492 (cnp->cn_flags & ISWHITEOUT))) && 493 (flags & ISLASTCN) && dp->i_effnlink != 0) { 494 /* 495 * Access for write is interpreted as allowing 496 * creation of files in the directory. 497 * 498 * XXX: Fix the comment above. 499 */ 500 if (flags & WILLBEDIR) 501 error = VOP_ACCESSX(vdp, VWRITE | VAPPEND, cred, cnp->cn_thread); 502 else 503 error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread); 504 if (error) 505 return (error); 506 /* 507 * Return an indication of where the new directory 508 * entry should be put. If we didn't find a slot, 509 * then set dp->i_count to 0 indicating 510 * that the new slot belongs at the end of the 511 * directory. If we found a slot, then the new entry 512 * can be put in the range from dp->i_offset to 513 * dp->i_offset + dp->i_count. 514 */ 515 if (slotstatus == NONE) { 516 dp->i_offset = roundup2(dp->i_size, DIRBLKSIZ); 517 dp->i_count = 0; 518 enduseful = dp->i_offset; 519 } else if (nameiop == DELETE) { 520 dp->i_offset = slotoffset; 521 if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0) 522 dp->i_count = 0; 523 else 524 dp->i_count = dp->i_offset - prevoff; 525 } else { 526 dp->i_offset = slotoffset; 527 dp->i_count = slotsize; 528 if (enduseful < slotoffset + slotsize) 529 enduseful = slotoffset + slotsize; 530 } 531 dp->i_endoff = roundup2(enduseful, DIRBLKSIZ); 532 /* 533 * We return with the directory locked, so that 534 * the parameters we set up above will still be 535 * valid if we actually decide to do a direnter(). 536 * We return ni_vp == NULL to indicate that the entry 537 * does not currently exist; we leave a pointer to 538 * the (locked) directory inode in ndp->ni_dvp. 539 * The pathname buffer is saved so that the name 540 * can be obtained later. 541 * 542 * NB - if the directory is unlocked, then this 543 * information cannot be used. 544 */ 545 cnp->cn_flags |= SAVENAME; 546 return (EJUSTRETURN); 547 } 548 /* 549 * Insert name into cache (as non-existent) if appropriate. 550 */ 551 if ((cnp->cn_flags & MAKEENTRY) && nameiop != CREATE) 552 cache_enter(vdp, NULL, cnp); 553 return (ENOENT); 554 555 found: 556 if (dd_ino != NULL) 557 *dd_ino = ino; 558 if (numdirpasses == 2) 559 nchstats.ncs_pass2++; 560 /* 561 * Check that directory length properly reflects presence 562 * of this entry. 563 */ 564 if (i_offset + DIRSIZ(OFSFMT(vdp), ep) > dp->i_size) { 565 ufs_dirbad(dp, i_offset, "i_size too small"); 566 dp->i_size = i_offset + DIRSIZ(OFSFMT(vdp), ep); 567 DIP_SET(dp, i_size, dp->i_size); 568 dp->i_flag |= IN_CHANGE | IN_UPDATE; 569 } 570 brelse(bp); 571 572 /* 573 * Found component in pathname. 574 * If the final component of path name, save information 575 * in the cache as to where the entry was found. 576 */ 577 if ((flags & ISLASTCN) && nameiop == LOOKUP) 578 dp->i_diroff = i_offset &~ (DIRBLKSIZ - 1); 579 580 /* 581 * If deleting, and at end of pathname, return 582 * parameters which can be used to remove file. 583 */ 584 if (nameiop == DELETE && (flags & ISLASTCN)) { 585 if (flags & LOCKPARENT) 586 ASSERT_VOP_ELOCKED(vdp, __FUNCTION__); 587 /* 588 * Return pointer to current entry in dp->i_offset, 589 * and distance past previous entry (if there 590 * is a previous entry in this block) in dp->i_count. 591 * Save directory inode pointer in ndp->ni_dvp for dirremove(). 592 * 593 * Technically we shouldn't be setting these in the 594 * WANTPARENT case (first lookup in rename()), but any 595 * lookups that will result in directory changes will 596 * overwrite these. 597 */ 598 dp->i_offset = i_offset; 599 if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0) 600 dp->i_count = 0; 601 else 602 dp->i_count = dp->i_offset - prevoff; 603 if (dd_ino != NULL) 604 return (0); 605 if ((error = VFS_VGET(vdp->v_mount, ino, 606 LK_EXCLUSIVE, &tdp)) != 0) 607 return (error); 608 error = ufs_delete_denied(vdp, tdp, cred, cnp->cn_thread); 609 if (error) { 610 vput(tdp); 611 return (error); 612 } 613 if (dp->i_number == ino) { 614 VREF(vdp); 615 *vpp = vdp; 616 vput(tdp); 617 return (0); 618 } 619 620 *vpp = tdp; 621 return (0); 622 } 623 624 /* 625 * If rewriting (RENAME), return the inode and the 626 * information required to rewrite the present directory 627 * Must get inode of directory entry to verify it's a 628 * regular file, or empty directory. 629 */ 630 if (nameiop == RENAME && (flags & ISLASTCN)) { 631 if (flags & WILLBEDIR) 632 error = VOP_ACCESSX(vdp, VWRITE | VAPPEND, cred, cnp->cn_thread); 633 else 634 error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread); 635 if (error) 636 return (error); 637 /* 638 * Careful about locking second inode. 639 * This can only occur if the target is ".". 640 */ 641 dp->i_offset = i_offset; 642 if (dp->i_number == ino) 643 return (EISDIR); 644 if (dd_ino != NULL) 645 return (0); 646 if ((error = VFS_VGET(vdp->v_mount, ino, 647 LK_EXCLUSIVE, &tdp)) != 0) 648 return (error); 649 650 error = ufs_delete_denied(vdp, tdp, cred, cnp->cn_thread); 651 if (error) { 652 vput(tdp); 653 return (error); 654 } 655 656 #ifdef SunOS_doesnt_do_that 657 /* 658 * The only purpose of this check is to return the correct 659 * error. Assume that we want to rename directory "a" 660 * to a file "b", and that we have no ACL_WRITE_DATA on 661 * a containing directory, but we _do_ have ACL_APPEND_DATA. 662 * In that case, the VOP_ACCESS check above will return 0, 663 * and the operation will fail with ENOTDIR instead 664 * of EACCESS. 665 */ 666 if (tdp->v_type == VDIR) 667 error = VOP_ACCESSX(vdp, VWRITE | VAPPEND, cred, cnp->cn_thread); 668 else 669 error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread); 670 if (error) { 671 vput(tdp); 672 return (error); 673 } 674 #endif 675 676 *vpp = tdp; 677 cnp->cn_flags |= SAVENAME; 678 return (0); 679 } 680 if (dd_ino != NULL) 681 return (0); 682 683 /* 684 * Step through the translation in the name. We do not `vput' the 685 * directory because we may need it again if a symbolic link 686 * is relative to the current directory. Instead we save it 687 * unlocked as "pdp". We must get the target inode before unlocking 688 * the directory to insure that the inode will not be removed 689 * before we get it. We prevent deadlock by always fetching 690 * inodes from the root, moving down the directory tree. Thus 691 * when following backward pointers ".." we must unlock the 692 * parent directory before getting the requested directory. 693 * There is a potential race condition here if both the current 694 * and parent directories are removed before the VFS_VGET for the 695 * inode associated with ".." returns. We hope that this occurs 696 * infrequently since we cannot avoid this race condition without 697 * implementing a sophisticated deadlock detection algorithm. 698 * Note also that this simple deadlock detection scheme will not 699 * work if the filesystem has any hard links other than ".." 700 * that point backwards in the directory structure. 701 */ 702 pdp = vdp; 703 if (flags & ISDOTDOT) { 704 error = vn_vget_ino(pdp, ino, cnp->cn_lkflags, &tdp); 705 if (error) 706 return (error); 707 708 /* 709 * Recheck that ".." entry in the vdp directory points 710 * to the inode we looked up before vdp lock was 711 * dropped. 712 */ 713 error = ufs_lookup_ino(pdp, NULL, cnp, &ino1); 714 if (error) { 715 vput(tdp); 716 return (error); 717 } 718 if (ino1 != ino) { 719 vput(tdp); 720 goto restart; 721 } 722 723 *vpp = tdp; 724 } else if (dp->i_number == ino) { 725 VREF(vdp); /* we want ourself, ie "." */ 726 /* 727 * When we lookup "." we still can be asked to lock it 728 * differently. 729 */ 730 ltype = cnp->cn_lkflags & LK_TYPE_MASK; 731 if (ltype != VOP_ISLOCKED(vdp)) { 732 if (ltype == LK_EXCLUSIVE) 733 vn_lock(vdp, LK_UPGRADE | LK_RETRY); 734 else /* if (ltype == LK_SHARED) */ 735 vn_lock(vdp, LK_DOWNGRADE | LK_RETRY); 736 /* 737 * Relock for the "." case may left us with 738 * reclaimed vnode. 739 */ 740 if (vdp->v_iflag & VI_DOOMED) { 741 vrele(vdp); 742 return (ENOENT); 743 } 744 } 745 *vpp = vdp; 746 } else { 747 error = VFS_VGET(pdp->v_mount, ino, cnp->cn_lkflags, &tdp); 748 if (error) 749 return (error); 750 *vpp = tdp; 751 } 752 753 /* 754 * Insert name into cache if appropriate. 755 */ 756 if (cnp->cn_flags & MAKEENTRY) 757 cache_enter(vdp, *vpp, cnp); 758 return (0); 759 } 760 761 void 762 ufs_dirbad(ip, offset, how) 763 struct inode *ip; 764 doff_t offset; 765 char *how; 766 { 767 struct mount *mp; 768 769 mp = ITOV(ip)->v_mount; 770 if ((mp->mnt_flag & MNT_RDONLY) == 0) 771 panic("ufs_dirbad: %s: bad dir ino %lu at offset %ld: %s", 772 mp->mnt_stat.f_mntonname, (u_long)ip->i_number, (long)offset, how); 773 else 774 (void)printf("%s: bad dir ino %lu at offset %ld: %s\n", 775 mp->mnt_stat.f_mntonname, (u_long)ip->i_number, (long)offset, how); 776 } 777 778 /* 779 * Do consistency checking on a directory entry: 780 * record length must be multiple of 4 781 * entry must fit in rest of its DIRBLKSIZ block 782 * record must be large enough to contain entry 783 * name is not longer than MAXNAMLEN 784 * name must be as long as advertised, and null terminated 785 */ 786 int 787 ufs_dirbadentry(dp, ep, entryoffsetinblock) 788 struct vnode *dp; 789 struct direct *ep; 790 int entryoffsetinblock; 791 { 792 int i, namlen; 793 794 # if (BYTE_ORDER == LITTLE_ENDIAN) 795 if (OFSFMT(dp)) 796 namlen = ep->d_type; 797 else 798 namlen = ep->d_namlen; 799 # else 800 namlen = ep->d_namlen; 801 # endif 802 if ((ep->d_reclen & 0x3) != 0 || 803 ep->d_reclen > DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1)) || 804 ep->d_reclen < DIRSIZ(OFSFMT(dp), ep) || namlen > MAXNAMLEN) { 805 /*return (1); */ 806 printf("First bad\n"); 807 goto bad; 808 } 809 if (ep->d_ino == 0) 810 return (0); 811 for (i = 0; i < namlen; i++) 812 if (ep->d_name[i] == '\0') { 813 /*return (1); */ 814 printf("Second bad\n"); 815 goto bad; 816 } 817 if (ep->d_name[i]) 818 goto bad; 819 return (0); 820 bad: 821 return (1); 822 } 823 824 /* 825 * Construct a new directory entry after a call to namei, using the 826 * parameters that it left in the componentname argument cnp. The 827 * argument ip is the inode to which the new directory entry will refer. 828 */ 829 void 830 ufs_makedirentry(ip, cnp, newdirp) 831 struct inode *ip; 832 struct componentname *cnp; 833 struct direct *newdirp; 834 { 835 836 #ifdef INVARIANTS 837 if ((cnp->cn_flags & SAVENAME) == 0) 838 panic("ufs_makedirentry: missing name"); 839 #endif 840 newdirp->d_ino = ip->i_number; 841 newdirp->d_namlen = cnp->cn_namelen; 842 bcopy(cnp->cn_nameptr, newdirp->d_name, (unsigned)cnp->cn_namelen + 1); 843 if (ITOV(ip)->v_mount->mnt_maxsymlinklen > 0) 844 newdirp->d_type = IFTODT(ip->i_mode); 845 else { 846 newdirp->d_type = 0; 847 # if (BYTE_ORDER == LITTLE_ENDIAN) 848 { u_char tmp = newdirp->d_namlen; 849 newdirp->d_namlen = newdirp->d_type; 850 newdirp->d_type = tmp; } 851 # endif 852 } 853 } 854 855 /* 856 * Write a directory entry after a call to namei, using the parameters 857 * that it left in nameidata. The argument dirp is the new directory 858 * entry contents. Dvp is a pointer to the directory to be written, 859 * which was left locked by namei. Remaining parameters (dp->i_offset, 860 * dp->i_count) indicate how the space for the new entry is to be obtained. 861 * Non-null bp indicates that a directory is being created (for the 862 * soft dependency code). 863 */ 864 int 865 ufs_direnter(dvp, tvp, dirp, cnp, newdirbp, isrename) 866 struct vnode *dvp; 867 struct vnode *tvp; 868 struct direct *dirp; 869 struct componentname *cnp; 870 struct buf *newdirbp; 871 int isrename; 872 { 873 struct ucred *cr; 874 struct thread *td; 875 int newentrysize; 876 struct inode *dp; 877 struct buf *bp; 878 u_int dsize; 879 struct direct *ep, *nep; 880 int error, ret, blkoff, loc, spacefree, flags, namlen; 881 char *dirbuf; 882 883 td = curthread; /* XXX */ 884 cr = td->td_ucred; 885 886 dp = VTOI(dvp); 887 newentrysize = DIRSIZ(OFSFMT(dvp), dirp); 888 889 if (dp->i_count == 0) { 890 /* 891 * If dp->i_count is 0, then namei could find no 892 * space in the directory. Here, dp->i_offset will 893 * be on a directory block boundary and we will write the 894 * new entry into a fresh block. 895 */ 896 if (dp->i_offset & (DIRBLKSIZ - 1)) 897 panic("ufs_direnter: newblk"); 898 flags = BA_CLRBUF; 899 if (!DOINGSOFTDEP(dvp) && !DOINGASYNC(dvp)) 900 flags |= IO_SYNC; 901 #ifdef QUOTA 902 if ((error = getinoquota(dp)) != 0) { 903 if (DOINGSOFTDEP(dvp) && newdirbp != NULL) 904 bdwrite(newdirbp); 905 return (error); 906 } 907 #endif 908 if ((error = UFS_BALLOC(dvp, (off_t)dp->i_offset, DIRBLKSIZ, 909 cr, flags, &bp)) != 0) { 910 if (DOINGSOFTDEP(dvp) && newdirbp != NULL) 911 bdwrite(newdirbp); 912 return (error); 913 } 914 dp->i_size = dp->i_offset + DIRBLKSIZ; 915 DIP_SET(dp, i_size, dp->i_size); 916 dp->i_flag |= IN_CHANGE | IN_UPDATE; 917 vnode_pager_setsize(dvp, (u_long)dp->i_size); 918 dirp->d_reclen = DIRBLKSIZ; 919 blkoff = dp->i_offset & 920 (VFSTOUFS(dvp->v_mount)->um_mountp->mnt_stat.f_iosize - 1); 921 bcopy((caddr_t)dirp, (caddr_t)bp->b_data + blkoff,newentrysize); 922 #ifdef UFS_DIRHASH 923 if (dp->i_dirhash != NULL) { 924 ufsdirhash_newblk(dp, dp->i_offset); 925 ufsdirhash_add(dp, dirp, dp->i_offset); 926 ufsdirhash_checkblock(dp, (char *)bp->b_data + blkoff, 927 dp->i_offset); 928 } 929 #endif 930 if (DOINGSOFTDEP(dvp)) { 931 /* 932 * Ensure that the entire newly allocated block is a 933 * valid directory so that future growth within the 934 * block does not have to ensure that the block is 935 * written before the inode. 936 */ 937 blkoff += DIRBLKSIZ; 938 while (blkoff < bp->b_bcount) { 939 ((struct direct *) 940 (bp->b_data + blkoff))->d_reclen = DIRBLKSIZ; 941 blkoff += DIRBLKSIZ; 942 } 943 if (softdep_setup_directory_add(bp, dp, dp->i_offset, 944 dirp->d_ino, newdirbp, 1)) 945 dp->i_flag |= IN_NEEDSYNC; 946 #ifdef JOURNALED_SOFTUPDATES 947 if (newdirbp) 948 bdwrite(newdirbp); 949 #endif 950 bdwrite(bp); 951 if ((dp->i_flag & IN_NEEDSYNC) == 0) 952 return (UFS_UPDATE(dvp, 0)); 953 /* 954 * We have just allocated a directory block in an 955 * indirect block. We must prevent holes in the 956 * directory created if directory entries are 957 * written out of order. To accomplish this we 958 * fsync when we extend a directory into indirects. 959 * During rename it's not safe to drop the tvp lock 960 * so sync must be delayed until it is. 961 * 962 * This synchronous step could be removed if fsck and 963 * the kernel were taught to fill in sparse 964 * directories rather than panic. 965 */ 966 if (isrename) 967 return (0); 968 if (tvp != NULL) 969 VOP_UNLOCK(tvp, 0); 970 error = VOP_FSYNC(dvp, MNT_WAIT, td); 971 if (tvp != NULL) 972 vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY); 973 return (error); 974 } 975 if (DOINGASYNC(dvp)) { 976 bdwrite(bp); 977 return (UFS_UPDATE(dvp, 0)); 978 } 979 error = bwrite(bp); 980 ret = UFS_UPDATE(dvp, 1); 981 if (error == 0) 982 return (ret); 983 return (error); 984 } 985 986 /* 987 * If dp->i_count is non-zero, then namei found space for the new 988 * entry in the range dp->i_offset to dp->i_offset + dp->i_count 989 * in the directory. To use this space, we may have to compact 990 * the entries located there, by copying them together towards the 991 * beginning of the block, leaving the free space in one usable 992 * chunk at the end. 993 */ 994 995 /* 996 * Increase size of directory if entry eats into new space. 997 * This should never push the size past a new multiple of 998 * DIRBLKSIZE. 999 * 1000 * N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN. 1001 */ 1002 if (dp->i_offset + dp->i_count > dp->i_size) { 1003 dp->i_size = dp->i_offset + dp->i_count; 1004 DIP_SET(dp, i_size, dp->i_size); 1005 } 1006 /* 1007 * Get the block containing the space for the new directory entry. 1008 */ 1009 error = UFS_BLKATOFF(dvp, (off_t)dp->i_offset, &dirbuf, &bp); 1010 if (error) { 1011 if (DOINGSOFTDEP(dvp) && newdirbp != NULL) 1012 bdwrite(newdirbp); 1013 return (error); 1014 } 1015 /* 1016 * Find space for the new entry. In the simple case, the entry at 1017 * offset base will have the space. If it does not, then namei 1018 * arranged that compacting the region dp->i_offset to 1019 * dp->i_offset + dp->i_count would yield the space. 1020 */ 1021 ep = (struct direct *)dirbuf; 1022 dsize = ep->d_ino ? DIRSIZ(OFSFMT(dvp), ep) : 0; 1023 spacefree = ep->d_reclen - dsize; 1024 for (loc = ep->d_reclen; loc < dp->i_count; ) { 1025 nep = (struct direct *)(dirbuf + loc); 1026 1027 /* Trim the existing slot (NB: dsize may be zero). */ 1028 ep->d_reclen = dsize; 1029 ep = (struct direct *)((char *)ep + dsize); 1030 1031 /* Read nep->d_reclen now as the bcopy() may clobber it. */ 1032 loc += nep->d_reclen; 1033 if (nep->d_ino == 0) { 1034 /* 1035 * A mid-block unused entry. Such entries are 1036 * never created by the kernel, but fsck_ffs 1037 * can create them (and it doesn't fix them). 1038 * 1039 * Add up the free space, and initialise the 1040 * relocated entry since we don't bcopy it. 1041 */ 1042 spacefree += nep->d_reclen; 1043 ep->d_ino = 0; 1044 dsize = 0; 1045 continue; 1046 } 1047 dsize = DIRSIZ(OFSFMT(dvp), nep); 1048 spacefree += nep->d_reclen - dsize; 1049 #ifdef UFS_DIRHASH 1050 if (dp->i_dirhash != NULL) 1051 ufsdirhash_move(dp, nep, 1052 dp->i_offset + ((char *)nep - dirbuf), 1053 dp->i_offset + ((char *)ep - dirbuf)); 1054 #endif 1055 if (DOINGSOFTDEP(dvp)) 1056 softdep_change_directoryentry_offset(dp, dirbuf, 1057 (caddr_t)nep, (caddr_t)ep, dsize); 1058 else 1059 bcopy((caddr_t)nep, (caddr_t)ep, dsize); 1060 } 1061 /* 1062 * Here, `ep' points to a directory entry containing `dsize' in-use 1063 * bytes followed by `spacefree' unused bytes. If ep->d_ino == 0, 1064 * then the entry is completely unused (dsize == 0). The value 1065 * of ep->d_reclen is always indeterminate. 1066 * 1067 * Update the pointer fields in the previous entry (if any), 1068 * copy in the new entry, and write out the block. 1069 */ 1070 # if (BYTE_ORDER == LITTLE_ENDIAN) 1071 if (OFSFMT(dvp)) 1072 namlen = ep->d_type; 1073 else 1074 namlen = ep->d_namlen; 1075 # else 1076 namlen = ep->d_namlen; 1077 # endif 1078 if (ep->d_ino == 0 || 1079 (ep->d_ino == WINO && namlen == dirp->d_namlen && 1080 bcmp(ep->d_name, dirp->d_name, dirp->d_namlen) == 0)) { 1081 if (spacefree + dsize < newentrysize) 1082 panic("ufs_direnter: compact1"); 1083 dirp->d_reclen = spacefree + dsize; 1084 } else { 1085 if (spacefree < newentrysize) 1086 panic("ufs_direnter: compact2"); 1087 dirp->d_reclen = spacefree; 1088 ep->d_reclen = dsize; 1089 ep = (struct direct *)((char *)ep + dsize); 1090 } 1091 #ifdef UFS_DIRHASH 1092 if (dp->i_dirhash != NULL && (ep->d_ino == 0 || 1093 dirp->d_reclen == spacefree)) 1094 ufsdirhash_add(dp, dirp, dp->i_offset + ((char *)ep - dirbuf)); 1095 #endif 1096 bcopy((caddr_t)dirp, (caddr_t)ep, (u_int)newentrysize); 1097 #ifdef UFS_DIRHASH 1098 if (dp->i_dirhash != NULL) 1099 ufsdirhash_checkblock(dp, dirbuf - 1100 (dp->i_offset & (DIRBLKSIZ - 1)), 1101 dp->i_offset & ~(DIRBLKSIZ - 1)); 1102 #endif 1103 1104 if (DOINGSOFTDEP(dvp)) { 1105 (void) softdep_setup_directory_add(bp, dp, 1106 dp->i_offset + (caddr_t)ep - dirbuf, 1107 dirp->d_ino, newdirbp, 0); 1108 #ifdef JOURNALED_SOFTUPDATES 1109 if (newdirbp != NULL) 1110 bdwrite(newdirbp); 1111 #endif 1112 bdwrite(bp); 1113 } else { 1114 if (DOINGASYNC(dvp)) { 1115 bdwrite(bp); 1116 error = 0; 1117 } else { 1118 error = bwrite(bp); 1119 } 1120 } 1121 dp->i_flag |= IN_CHANGE | IN_UPDATE; 1122 /* 1123 * If all went well, and the directory can be shortened, proceed 1124 * with the truncation. Note that we have to unlock the inode for 1125 * the entry that we just entered, as the truncation may need to 1126 * lock other inodes which can lead to deadlock if we also hold a 1127 * lock on the newly entered node. 1128 */ 1129 if (isrename == 0 && error == 0 && 1130 dp->i_endoff && dp->i_endoff < dp->i_size) { 1131 if (tvp != NULL) 1132 VOP_UNLOCK(tvp, 0); 1133 #ifdef UFS_DIRHASH 1134 if (dp->i_dirhash != NULL) 1135 ufsdirhash_dirtrunc(dp, dp->i_endoff); 1136 #endif 1137 (void) UFS_TRUNCATE(dvp, (off_t)dp->i_endoff, 1138 IO_NORMAL | IO_SYNC, cr, td); 1139 if (tvp != NULL) 1140 vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY); 1141 } 1142 return (error); 1143 } 1144 1145 /* 1146 * Remove a directory entry after a call to namei, using 1147 * the parameters which it left in nameidata. The entry 1148 * dp->i_offset contains the offset into the directory of the 1149 * entry to be eliminated. The dp->i_count field contains the 1150 * size of the previous record in the directory. If this 1151 * is 0, the first entry is being deleted, so we need only 1152 * zero the inode number to mark the entry as free. If the 1153 * entry is not the first in the directory, we must reclaim 1154 * the space of the now empty record by adding the record size 1155 * to the size of the previous entry. 1156 */ 1157 int 1158 ufs_dirremove(dvp, ip, flags, isrmdir) 1159 struct vnode *dvp; 1160 struct inode *ip; 1161 int flags; 1162 int isrmdir; 1163 { 1164 struct inode *dp; 1165 struct direct *ep, *rep; 1166 struct buf *bp; 1167 int error; 1168 1169 dp = VTOI(dvp); 1170 1171 if (flags & DOWHITEOUT) { 1172 /* 1173 * Whiteout entry: set d_ino to WINO. 1174 */ 1175 if ((error = 1176 UFS_BLKATOFF(dvp, (off_t)dp->i_offset, (char **)&ep, &bp)) != 0) 1177 return (error); 1178 ep->d_ino = WINO; 1179 ep->d_type = DT_WHT; 1180 goto out; 1181 } 1182 1183 if ((error = UFS_BLKATOFF(dvp, 1184 (off_t)(dp->i_offset - dp->i_count), (char **)&ep, &bp)) != 0) 1185 return (error); 1186 1187 /* Set 'rep' to the entry being removed. */ 1188 if (dp->i_count == 0) 1189 rep = ep; 1190 else 1191 rep = (struct direct *)((char *)ep + ep->d_reclen); 1192 #ifdef UFS_DIRHASH 1193 /* 1194 * Remove the dirhash entry. This is complicated by the fact 1195 * that `ep' is the previous entry when dp->i_count != 0. 1196 */ 1197 if (dp->i_dirhash != NULL) 1198 ufsdirhash_remove(dp, rep, dp->i_offset); 1199 #endif 1200 if (dp->i_count == 0) { 1201 /* 1202 * First entry in block: set d_ino to zero. 1203 */ 1204 ep->d_ino = 0; 1205 } else { 1206 /* 1207 * Collapse new free space into previous entry. 1208 */ 1209 ep->d_reclen += rep->d_reclen; 1210 } 1211 #ifdef UFS_DIRHASH 1212 if (dp->i_dirhash != NULL) 1213 ufsdirhash_checkblock(dp, (char *)ep - 1214 ((dp->i_offset - dp->i_count) & (DIRBLKSIZ - 1)), 1215 dp->i_offset & ~(DIRBLKSIZ - 1)); 1216 #endif 1217 out: 1218 if (DOINGSOFTDEP(dvp)) { 1219 if (ip) { 1220 ip->i_effnlink--; 1221 softdep_change_linkcnt(ip); 1222 softdep_setup_remove(bp, dp, ip, isrmdir); 1223 } 1224 if (softdep_slowdown(dvp)) { 1225 error = bwrite(bp); 1226 } else { 1227 bdwrite(bp); 1228 error = 0; 1229 } 1230 } else { 1231 if (ip) { 1232 ip->i_effnlink--; 1233 ip->i_nlink--; 1234 DIP_SET(ip, i_nlink, ip->i_nlink); 1235 ip->i_flag |= IN_CHANGE; 1236 } 1237 if (flags & DOWHITEOUT) 1238 error = bwrite(bp); 1239 else if (DOINGASYNC(dvp) && dp->i_count != 0) { 1240 bdwrite(bp); 1241 error = 0; 1242 } else 1243 error = bwrite(bp); 1244 } 1245 dp->i_flag |= IN_CHANGE | IN_UPDATE; 1246 /* 1247 * If the last named reference to a snapshot goes away, 1248 * drop its snapshot reference so that it will be reclaimed 1249 * when last open reference goes away. 1250 */ 1251 if (ip != 0 && (ip->i_flags & SF_SNAPSHOT) != 0 && ip->i_effnlink == 0) 1252 UFS_SNAPGONE(ip); 1253 return (error); 1254 } 1255 1256 /* 1257 * Rewrite an existing directory entry to point at the inode 1258 * supplied. The parameters describing the directory entry are 1259 * set up by a call to namei. 1260 */ 1261 int 1262 ufs_dirrewrite(dp, oip, newinum, newtype, isrmdir) 1263 struct inode *dp, *oip; 1264 ino_t newinum; 1265 int newtype; 1266 int isrmdir; 1267 { 1268 struct buf *bp; 1269 struct direct *ep; 1270 struct vnode *vdp = ITOV(dp); 1271 int error; 1272 1273 error = UFS_BLKATOFF(vdp, (off_t)dp->i_offset, (char **)&ep, &bp); 1274 if (error) 1275 return (error); 1276 ep->d_ino = newinum; 1277 if (!OFSFMT(vdp)) 1278 ep->d_type = newtype; 1279 oip->i_effnlink--; 1280 if (DOINGSOFTDEP(vdp)) { 1281 softdep_change_linkcnt(oip); 1282 softdep_setup_directory_change(bp, dp, oip, newinum, isrmdir); 1283 bdwrite(bp); 1284 } else { 1285 oip->i_nlink--; 1286 DIP_SET(oip, i_nlink, oip->i_nlink); 1287 oip->i_flag |= IN_CHANGE; 1288 if (DOINGASYNC(vdp)) { 1289 bdwrite(bp); 1290 error = 0; 1291 } else { 1292 error = bwrite(bp); 1293 } 1294 } 1295 dp->i_flag |= IN_CHANGE | IN_UPDATE; 1296 /* 1297 * If the last named reference to a snapshot goes away, 1298 * drop its snapshot reference so that it will be reclaimed 1299 * when last open reference goes away. 1300 */ 1301 if ((oip->i_flags & SF_SNAPSHOT) != 0 && oip->i_effnlink == 0) 1302 UFS_SNAPGONE(oip); 1303 return (error); 1304 } 1305 1306 /* 1307 * Check if a directory is empty or not. 1308 * Inode supplied must be locked. 1309 * 1310 * Using a struct dirtemplate here is not precisely 1311 * what we want, but better than using a struct direct. 1312 * 1313 * NB: does not handle corrupted directories. 1314 */ 1315 int 1316 ufs_dirempty(ip, parentino, cred) 1317 struct inode *ip; 1318 ino_t parentino; 1319 struct ucred *cred; 1320 { 1321 doff_t off; 1322 struct dirtemplate dbuf; 1323 struct direct *dp = (struct direct *)&dbuf; 1324 int error, count, namlen; 1325 #define MINDIRSIZ (sizeof (struct dirtemplate) / 2) 1326 1327 for (off = 0; off < ip->i_size; off += dp->d_reclen) { 1328 error = vn_rdwr(UIO_READ, ITOV(ip), (caddr_t)dp, MINDIRSIZ, 1329 off, UIO_SYSSPACE, IO_NODELOCKED | IO_NOMACCHECK, cred, 1330 NOCRED, &count, (struct thread *)0); 1331 /* 1332 * Since we read MINDIRSIZ, residual must 1333 * be 0 unless we're at end of file. 1334 */ 1335 if (error || count != 0) 1336 return (0); 1337 /* avoid infinite loops */ 1338 if (dp->d_reclen == 0) 1339 return (0); 1340 /* skip empty entries */ 1341 if (dp->d_ino == 0 || dp->d_ino == WINO) 1342 continue; 1343 /* accept only "." and ".." */ 1344 # if (BYTE_ORDER == LITTLE_ENDIAN) 1345 if (OFSFMT(ITOV(ip))) 1346 namlen = dp->d_type; 1347 else 1348 namlen = dp->d_namlen; 1349 # else 1350 namlen = dp->d_namlen; 1351 # endif 1352 if (namlen > 2) 1353 return (0); 1354 if (dp->d_name[0] != '.') 1355 return (0); 1356 /* 1357 * At this point namlen must be 1 or 2. 1358 * 1 implies ".", 2 implies ".." if second 1359 * char is also "." 1360 */ 1361 if (namlen == 1 && dp->d_ino == ip->i_number) 1362 continue; 1363 if (dp->d_name[1] == '.' && dp->d_ino == parentino) 1364 continue; 1365 return (0); 1366 } 1367 return (1); 1368 } 1369 1370 static int 1371 ufs_dir_dd_ino(struct vnode *vp, struct ucred *cred, ino_t *dd_ino) 1372 { 1373 struct dirtemplate dirbuf; 1374 int error, namlen; 1375 1376 if (vp->v_type != VDIR) 1377 return (ENOTDIR); 1378 error = vn_rdwr(UIO_READ, vp, (caddr_t)&dirbuf, 1379 sizeof (struct dirtemplate), (off_t)0, UIO_SYSSPACE, 1380 IO_NODELOCKED | IO_NOMACCHECK, cred, NOCRED, NULL, NULL); 1381 if (error != 0) 1382 return (error); 1383 #if (BYTE_ORDER == LITTLE_ENDIAN) 1384 if (OFSFMT(vp)) 1385 namlen = dirbuf.dotdot_type; 1386 else 1387 namlen = dirbuf.dotdot_namlen; 1388 #else 1389 namlen = dirbuf.dotdot_namlen; 1390 #endif 1391 if (namlen != 2 || dirbuf.dotdot_name[0] != '.' || 1392 dirbuf.dotdot_name[1] != '.') 1393 return (ENOTDIR); 1394 *dd_ino = dirbuf.dotdot_ino; 1395 return (0); 1396 } 1397 1398 /* 1399 * Check if source directory is in the path of the target directory. 1400 */ 1401 int 1402 ufs_checkpath(ino_t source_ino, ino_t parent_ino, struct inode *target, struct ucred *cred, ino_t *wait_ino) 1403 { 1404 struct mount *mp; 1405 struct vnode *tvp, *vp, *vp1; 1406 int error; 1407 ino_t dd_ino; 1408 1409 vp = tvp = ITOV(target); 1410 mp = vp->v_mount; 1411 *wait_ino = 0; 1412 if (target->i_number == source_ino) 1413 return (EEXIST); 1414 if (target->i_number == parent_ino) 1415 return (0); 1416 if (target->i_number == ROOTINO) 1417 return (0); 1418 for (;;) { 1419 error = ufs_dir_dd_ino(vp, cred, &dd_ino); 1420 if (error != 0) 1421 break; 1422 if (dd_ino == source_ino) { 1423 error = EINVAL; 1424 break; 1425 } 1426 if (dd_ino == ROOTINO) 1427 break; 1428 if (dd_ino == parent_ino) 1429 break; 1430 error = VFS_VGET(mp, dd_ino, LK_SHARED | LK_NOWAIT, &vp1); 1431 if (error != 0) { 1432 *wait_ino = dd_ino; 1433 break; 1434 } 1435 /* Recheck that ".." still points to vp1 after relock of vp */ 1436 error = ufs_dir_dd_ino(vp, cred, &dd_ino); 1437 if (error != 0) { 1438 vput(vp1); 1439 break; 1440 } 1441 /* Redo the check of ".." if directory was reparented */ 1442 if (dd_ino != VTOI(vp1)->i_number) { 1443 vput(vp1); 1444 continue; 1445 } 1446 if (vp != tvp) 1447 vput(vp); 1448 vp = vp1; 1449 } 1450 1451 if (error == ENOTDIR) 1452 panic("checkpath: .. not a directory\n"); 1453 if (vp != tvp) 1454 vput(vp); 1455 return (error); 1456 }
Cache object: 5dfd602c83f9280be93a817f101a9e7d
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