1 /* 2 * linux/fs/vfat/namei.c 3 * 4 * Written 1992,1993 by Werner Almesberger 5 * 6 * Windows95/Windows NT compatible extended MSDOS filesystem 7 * by Gordon Chaffee Copyright (C) 1995. Send bug reports for the 8 * VFAT filesystem to <chaffee@cs.berkeley.edu>. Specify 9 * what file operation caused you trouble and if you can duplicate 10 * the problem, send a script that demonstrates it. 11 * 12 * Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de> 13 * 14 * Support Multibyte characters and cleanup by 15 * OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> 16 */ 17 18 #include <linux/module.h> 19 #include <linux/ctype.h> 20 #include <linux/slab.h> 21 #include <linux/namei.h> 22 #include "fat.h" 23 24 static inline unsigned long vfat_d_version(struct dentry *dentry) 25 { 26 return (unsigned long) dentry->d_fsdata; 27 } 28 29 static inline void vfat_d_version_set(struct dentry *dentry, 30 unsigned long version) 31 { 32 dentry->d_fsdata = (void *) version; 33 } 34 35 /* 36 * If new entry was created in the parent, it could create the 8.3 37 * alias (the shortname of logname). So, the parent may have the 38 * negative-dentry which matches the created 8.3 alias. 39 * 40 * If it happened, the negative dentry isn't actually negative 41 * anymore. So, drop it. 42 */ 43 static int vfat_revalidate_shortname(struct dentry *dentry) 44 { 45 int ret = 1; 46 spin_lock(&dentry->d_lock); 47 if (vfat_d_version(dentry) != d_inode(dentry->d_parent)->i_version) 48 ret = 0; 49 spin_unlock(&dentry->d_lock); 50 return ret; 51 } 52 53 static int vfat_revalidate(struct dentry *dentry, unsigned int flags) 54 { 55 if (flags & LOOKUP_RCU) 56 return -ECHILD; 57 58 /* This is not negative dentry. Always valid. */ 59 if (d_really_is_positive(dentry)) 60 return 1; 61 return vfat_revalidate_shortname(dentry); 62 } 63 64 static int vfat_revalidate_ci(struct dentry *dentry, unsigned int flags) 65 { 66 if (flags & LOOKUP_RCU) 67 return -ECHILD; 68 69 /* 70 * This is not negative dentry. Always valid. 71 * 72 * Note, rename() to existing directory entry will have ->d_inode, 73 * and will use existing name which isn't specified name by user. 74 * 75 * We may be able to drop this positive dentry here. But dropping 76 * positive dentry isn't good idea. So it's unsupported like 77 * rename("filename", "FILENAME") for now. 78 */ 79 if (d_really_is_positive(dentry)) 80 return 1; 81 82 /* 83 * This may be nfsd (or something), anyway, we can't see the 84 * intent of this. So, since this can be for creation, drop it. 85 */ 86 if (!flags) 87 return 0; 88 89 /* 90 * Drop the negative dentry, in order to make sure to use the 91 * case sensitive name which is specified by user if this is 92 * for creation. 93 */ 94 if (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET)) 95 return 0; 96 97 return vfat_revalidate_shortname(dentry); 98 } 99 100 /* returns the length of a struct qstr, ignoring trailing dots */ 101 static unsigned int __vfat_striptail_len(unsigned int len, const char *name) 102 { 103 while (len && name[len - 1] == '.') 104 len--; 105 return len; 106 } 107 108 static unsigned int vfat_striptail_len(const struct qstr *qstr) 109 { 110 return __vfat_striptail_len(qstr->len, qstr->name); 111 } 112 113 /* 114 * Compute the hash for the vfat name corresponding to the dentry. 115 * Note: if the name is invalid, we leave the hash code unchanged so 116 * that the existing dentry can be used. The vfat fs routines will 117 * return ENOENT or EINVAL as appropriate. 118 */ 119 static int vfat_hash(const struct dentry *dentry, struct qstr *qstr) 120 { 121 qstr->hash = full_name_hash(dentry, qstr->name, vfat_striptail_len(qstr)); 122 return 0; 123 } 124 125 /* 126 * Compute the hash for the vfat name corresponding to the dentry. 127 * Note: if the name is invalid, we leave the hash code unchanged so 128 * that the existing dentry can be used. The vfat fs routines will 129 * return ENOENT or EINVAL as appropriate. 130 */ 131 static int vfat_hashi(const struct dentry *dentry, struct qstr *qstr) 132 { 133 struct nls_table *t = MSDOS_SB(dentry->d_sb)->nls_io; 134 const unsigned char *name; 135 unsigned int len; 136 unsigned long hash; 137 138 name = qstr->name; 139 len = vfat_striptail_len(qstr); 140 141 hash = init_name_hash(dentry); 142 while (len--) 143 hash = partial_name_hash(nls_tolower(t, *name++), hash); 144 qstr->hash = end_name_hash(hash); 145 146 return 0; 147 } 148 149 /* 150 * Case insensitive compare of two vfat names. 151 */ 152 static int vfat_cmpi(const struct dentry *dentry, 153 unsigned int len, const char *str, const struct qstr *name) 154 { 155 struct nls_table *t = MSDOS_SB(dentry->d_sb)->nls_io; 156 unsigned int alen, blen; 157 158 /* A filename cannot end in '.' or we treat it like it has none */ 159 alen = vfat_striptail_len(name); 160 blen = __vfat_striptail_len(len, str); 161 if (alen == blen) { 162 if (nls_strnicmp(t, name->name, str, alen) == 0) 163 return 0; 164 } 165 return 1; 166 } 167 168 /* 169 * Case sensitive compare of two vfat names. 170 */ 171 static int vfat_cmp(const struct dentry *dentry, 172 unsigned int len, const char *str, const struct qstr *name) 173 { 174 unsigned int alen, blen; 175 176 /* A filename cannot end in '.' or we treat it like it has none */ 177 alen = vfat_striptail_len(name); 178 blen = __vfat_striptail_len(len, str); 179 if (alen == blen) { 180 if (strncmp(name->name, str, alen) == 0) 181 return 0; 182 } 183 return 1; 184 } 185 186 static const struct dentry_operations vfat_ci_dentry_ops = { 187 .d_revalidate = vfat_revalidate_ci, 188 .d_hash = vfat_hashi, 189 .d_compare = vfat_cmpi, 190 }; 191 192 static const struct dentry_operations vfat_dentry_ops = { 193 .d_revalidate = vfat_revalidate, 194 .d_hash = vfat_hash, 195 .d_compare = vfat_cmp, 196 }; 197 198 /* Characters that are undesirable in an MS-DOS file name */ 199 200 static inline wchar_t vfat_bad_char(wchar_t w) 201 { 202 return (w < 0x0020) 203 || (w == '*') || (w == '?') || (w == '<') || (w == '>') 204 || (w == '|') || (w == '"') || (w == ':') || (w == '/') 205 || (w == '\\'); 206 } 207 208 static inline wchar_t vfat_replace_char(wchar_t w) 209 { 210 return (w == '[') || (w == ']') || (w == ';') || (w == ',') 211 || (w == '+') || (w == '='); 212 } 213 214 static wchar_t vfat_skip_char(wchar_t w) 215 { 216 return (w == '.') || (w == ' '); 217 } 218 219 static inline int vfat_is_used_badchars(const wchar_t *s, int len) 220 { 221 int i; 222 223 for (i = 0; i < len; i++) 224 if (vfat_bad_char(s[i])) 225 return -EINVAL; 226 227 if (s[i - 1] == ' ') /* last character cannot be space */ 228 return -EINVAL; 229 230 return 0; 231 } 232 233 static int vfat_find_form(struct inode *dir, unsigned char *name) 234 { 235 struct fat_slot_info sinfo; 236 int err = fat_scan(dir, name, &sinfo); 237 if (err) 238 return -ENOENT; 239 brelse(sinfo.bh); 240 return 0; 241 } 242 243 /* 244 * 1) Valid characters for the 8.3 format alias are any combination of 245 * letters, uppercase alphabets, digits, any of the 246 * following special characters: 247 * $ % ' ` - @ { } ~ ! # ( ) & _ ^ 248 * In this case Longfilename is not stored in disk. 249 * 250 * WinNT's Extension: 251 * File name and extension name is contain uppercase/lowercase 252 * only. And it is expressed by CASE_LOWER_BASE and CASE_LOWER_EXT. 253 * 254 * 2) File name is 8.3 format, but it contain the uppercase and 255 * lowercase char, muliti bytes char, etc. In this case numtail is not 256 * added, but Longfilename is stored. 257 * 258 * 3) When the one except for the above, or the following special 259 * character are contained: 260 * . [ ] ; , + = 261 * numtail is added, and Longfilename must be stored in disk . 262 */ 263 struct shortname_info { 264 unsigned char lower:1, 265 upper:1, 266 valid:1; 267 }; 268 #define INIT_SHORTNAME_INFO(x) do { \ 269 (x)->lower = 1; \ 270 (x)->upper = 1; \ 271 (x)->valid = 1; \ 272 } while (0) 273 274 static inline int to_shortname_char(struct nls_table *nls, 275 unsigned char *buf, int buf_size, 276 wchar_t *src, struct shortname_info *info) 277 { 278 int len; 279 280 if (vfat_skip_char(*src)) { 281 info->valid = 0; 282 return 0; 283 } 284 if (vfat_replace_char(*src)) { 285 info->valid = 0; 286 buf[0] = '_'; 287 return 1; 288 } 289 290 len = nls->uni2char(*src, buf, buf_size); 291 if (len <= 0) { 292 info->valid = 0; 293 buf[0] = '_'; 294 len = 1; 295 } else if (len == 1) { 296 unsigned char prev = buf[0]; 297 298 if (buf[0] >= 0x7F) { 299 info->lower = 0; 300 info->upper = 0; 301 } 302 303 buf[0] = nls_toupper(nls, buf[0]); 304 if (isalpha(buf[0])) { 305 if (buf[0] == prev) 306 info->lower = 0; 307 else 308 info->upper = 0; 309 } 310 } else { 311 info->lower = 0; 312 info->upper = 0; 313 } 314 315 return len; 316 } 317 318 /* 319 * Given a valid longname, create a unique shortname. Make sure the 320 * shortname does not exist 321 * Returns negative number on error, 0 for a normal 322 * return, and 1 for valid shortname 323 */ 324 static int vfat_create_shortname(struct inode *dir, struct nls_table *nls, 325 wchar_t *uname, int ulen, 326 unsigned char *name_res, unsigned char *lcase) 327 { 328 struct fat_mount_options *opts = &MSDOS_SB(dir->i_sb)->options; 329 wchar_t *ip, *ext_start, *end, *name_start; 330 unsigned char base[9], ext[4], buf[5], *p; 331 unsigned char charbuf[NLS_MAX_CHARSET_SIZE]; 332 int chl, chi; 333 int sz = 0, extlen, baselen, i, numtail_baselen, numtail2_baselen; 334 int is_shortname; 335 struct shortname_info base_info, ext_info; 336 337 is_shortname = 1; 338 INIT_SHORTNAME_INFO(&base_info); 339 INIT_SHORTNAME_INFO(&ext_info); 340 341 /* Now, we need to create a shortname from the long name */ 342 ext_start = end = &uname[ulen]; 343 while (--ext_start >= uname) { 344 if (*ext_start == 0x002E) { /* is `.' */ 345 if (ext_start == end - 1) { 346 sz = ulen; 347 ext_start = NULL; 348 } 349 break; 350 } 351 } 352 353 if (ext_start == uname - 1) { 354 sz = ulen; 355 ext_start = NULL; 356 } else if (ext_start) { 357 /* 358 * Names which start with a dot could be just 359 * an extension eg. "...test". In this case Win95 360 * uses the extension as the name and sets no extension. 361 */ 362 name_start = &uname[0]; 363 while (name_start < ext_start) { 364 if (!vfat_skip_char(*name_start)) 365 break; 366 name_start++; 367 } 368 if (name_start != ext_start) { 369 sz = ext_start - uname; 370 ext_start++; 371 } else { 372 sz = ulen; 373 ext_start = NULL; 374 } 375 } 376 377 numtail_baselen = 6; 378 numtail2_baselen = 2; 379 for (baselen = i = 0, p = base, ip = uname; i < sz; i++, ip++) { 380 chl = to_shortname_char(nls, charbuf, sizeof(charbuf), 381 ip, &base_info); 382 if (chl == 0) 383 continue; 384 385 if (baselen < 2 && (baselen + chl) > 2) 386 numtail2_baselen = baselen; 387 if (baselen < 6 && (baselen + chl) > 6) 388 numtail_baselen = baselen; 389 for (chi = 0; chi < chl; chi++) { 390 *p++ = charbuf[chi]; 391 baselen++; 392 if (baselen >= 8) 393 break; 394 } 395 if (baselen >= 8) { 396 if ((chi < chl - 1) || (ip + 1) - uname < sz) 397 is_shortname = 0; 398 break; 399 } 400 } 401 if (baselen == 0) { 402 return -EINVAL; 403 } 404 405 extlen = 0; 406 if (ext_start) { 407 for (p = ext, ip = ext_start; extlen < 3 && ip < end; ip++) { 408 chl = to_shortname_char(nls, charbuf, sizeof(charbuf), 409 ip, &ext_info); 410 if (chl == 0) 411 continue; 412 413 if ((extlen + chl) > 3) { 414 is_shortname = 0; 415 break; 416 } 417 for (chi = 0; chi < chl; chi++) { 418 *p++ = charbuf[chi]; 419 extlen++; 420 } 421 if (extlen >= 3) { 422 if (ip + 1 != end) 423 is_shortname = 0; 424 break; 425 } 426 } 427 } 428 ext[extlen] = '\0'; 429 base[baselen] = '\0'; 430 431 /* Yes, it can happen. ".\xe5" would do it. */ 432 if (base[0] == DELETED_FLAG) 433 base[0] = 0x05; 434 435 /* OK, at this point we know that base is not longer than 8 symbols, 436 * ext is not longer than 3, base is nonempty, both don't contain 437 * any bad symbols (lowercase transformed to uppercase). 438 */ 439 440 memset(name_res, ' ', MSDOS_NAME); 441 memcpy(name_res, base, baselen); 442 memcpy(name_res + 8, ext, extlen); 443 *lcase = 0; 444 if (is_shortname && base_info.valid && ext_info.valid) { 445 if (vfat_find_form(dir, name_res) == 0) 446 return -EEXIST; 447 448 if (opts->shortname & VFAT_SFN_CREATE_WIN95) { 449 return (base_info.upper && ext_info.upper); 450 } else if (opts->shortname & VFAT_SFN_CREATE_WINNT) { 451 if ((base_info.upper || base_info.lower) && 452 (ext_info.upper || ext_info.lower)) { 453 if (!base_info.upper && base_info.lower) 454 *lcase |= CASE_LOWER_BASE; 455 if (!ext_info.upper && ext_info.lower) 456 *lcase |= CASE_LOWER_EXT; 457 return 1; 458 } 459 return 0; 460 } else { 461 BUG(); 462 } 463 } 464 465 if (opts->numtail == 0) 466 if (vfat_find_form(dir, name_res) < 0) 467 return 0; 468 469 /* 470 * Try to find a unique extension. This used to 471 * iterate through all possibilities sequentially, 472 * but that gave extremely bad performance. Windows 473 * only tries a few cases before using random 474 * values for part of the base. 475 */ 476 477 if (baselen > 6) { 478 baselen = numtail_baselen; 479 name_res[7] = ' '; 480 } 481 name_res[baselen] = '~'; 482 for (i = 1; i < 10; i++) { 483 name_res[baselen + 1] = i + '0'; 484 if (vfat_find_form(dir, name_res) < 0) 485 return 0; 486 } 487 488 i = jiffies; 489 sz = (jiffies >> 16) & 0x7; 490 if (baselen > 2) { 491 baselen = numtail2_baselen; 492 name_res[7] = ' '; 493 } 494 name_res[baselen + 4] = '~'; 495 name_res[baselen + 5] = '1' + sz; 496 while (1) { 497 snprintf(buf, sizeof(buf), "%04X", i & 0xffff); 498 memcpy(&name_res[baselen], buf, 4); 499 if (vfat_find_form(dir, name_res) < 0) 500 break; 501 i -= 11; 502 } 503 return 0; 504 } 505 506 /* Translate a string, including coded sequences into Unicode */ 507 static int 508 xlate_to_uni(const unsigned char *name, int len, unsigned char *outname, 509 int *longlen, int *outlen, int escape, int utf8, 510 struct nls_table *nls) 511 { 512 const unsigned char *ip; 513 unsigned char nc; 514 unsigned char *op; 515 unsigned int ec; 516 int i, k, fill; 517 int charlen; 518 519 if (utf8) { 520 *outlen = utf8s_to_utf16s(name, len, UTF16_HOST_ENDIAN, 521 (wchar_t *) outname, FAT_LFN_LEN + 2); 522 if (*outlen < 0) 523 return *outlen; 524 else if (*outlen > FAT_LFN_LEN) 525 return -ENAMETOOLONG; 526 527 op = &outname[*outlen * sizeof(wchar_t)]; 528 } else { 529 for (i = 0, ip = name, op = outname, *outlen = 0; 530 i < len && *outlen < FAT_LFN_LEN; 531 *outlen += 1) { 532 if (escape && (*ip == ':')) { 533 if (i > len - 5) 534 return -EINVAL; 535 ec = 0; 536 for (k = 1; k < 5; k++) { 537 nc = ip[k]; 538 ec <<= 4; 539 if (nc >= '0' && nc <= '9') { 540 ec |= nc - '0'; 541 continue; 542 } 543 if (nc >= 'a' && nc <= 'f') { 544 ec |= nc - ('a' - 10); 545 continue; 546 } 547 if (nc >= 'A' && nc <= 'F') { 548 ec |= nc - ('A' - 10); 549 continue; 550 } 551 return -EINVAL; 552 } 553 *op++ = ec & 0xFF; 554 *op++ = ec >> 8; 555 ip += 5; 556 i += 5; 557 } else { 558 charlen = nls->char2uni(ip, len - i, 559 (wchar_t *)op); 560 if (charlen < 0) 561 return -EINVAL; 562 ip += charlen; 563 i += charlen; 564 op += 2; 565 } 566 } 567 if (i < len) 568 return -ENAMETOOLONG; 569 } 570 571 *longlen = *outlen; 572 if (*outlen % 13) { 573 *op++ = 0; 574 *op++ = 0; 575 *outlen += 1; 576 if (*outlen % 13) { 577 fill = 13 - (*outlen % 13); 578 for (i = 0; i < fill; i++) { 579 *op++ = 0xff; 580 *op++ = 0xff; 581 } 582 *outlen += fill; 583 } 584 } 585 586 return 0; 587 } 588 589 static int vfat_build_slots(struct inode *dir, const unsigned char *name, 590 int len, int is_dir, int cluster, 591 struct timespec *ts, 592 struct msdos_dir_slot *slots, int *nr_slots) 593 { 594 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb); 595 struct fat_mount_options *opts = &sbi->options; 596 struct msdos_dir_slot *ps; 597 struct msdos_dir_entry *de; 598 unsigned char cksum, lcase; 599 unsigned char msdos_name[MSDOS_NAME]; 600 wchar_t *uname; 601 __le16 time, date; 602 u8 time_cs; 603 int err, ulen, usize, i; 604 loff_t offset; 605 606 *nr_slots = 0; 607 608 uname = __getname(); 609 if (!uname) 610 return -ENOMEM; 611 612 err = xlate_to_uni(name, len, (unsigned char *)uname, &ulen, &usize, 613 opts->unicode_xlate, opts->utf8, sbi->nls_io); 614 if (err) 615 goto out_free; 616 617 err = vfat_is_used_badchars(uname, ulen); 618 if (err) 619 goto out_free; 620 621 err = vfat_create_shortname(dir, sbi->nls_disk, uname, ulen, 622 msdos_name, &lcase); 623 if (err < 0) 624 goto out_free; 625 else if (err == 1) { 626 de = (struct msdos_dir_entry *)slots; 627 err = 0; 628 goto shortname; 629 } 630 631 /* build the entry of long file name */ 632 cksum = fat_checksum(msdos_name); 633 634 *nr_slots = usize / 13; 635 for (ps = slots, i = *nr_slots; i > 0; i--, ps++) { 636 ps->id = i; 637 ps->attr = ATTR_EXT; 638 ps->reserved = 0; 639 ps->alias_checksum = cksum; 640 ps->start = 0; 641 offset = (i - 1) * 13; 642 fatwchar_to16(ps->name0_4, uname + offset, 5); 643 fatwchar_to16(ps->name5_10, uname + offset + 5, 6); 644 fatwchar_to16(ps->name11_12, uname + offset + 11, 2); 645 } 646 slots[0].id |= 0x40; 647 de = (struct msdos_dir_entry *)ps; 648 649 shortname: 650 /* build the entry of 8.3 alias name */ 651 (*nr_slots)++; 652 memcpy(de->name, msdos_name, MSDOS_NAME); 653 de->attr = is_dir ? ATTR_DIR : ATTR_ARCH; 654 de->lcase = lcase; 655 fat_time_unix2fat(sbi, ts, &time, &date, &time_cs); 656 de->time = de->ctime = time; 657 de->date = de->cdate = de->adate = date; 658 de->ctime_cs = time_cs; 659 fat_set_start(de, cluster); 660 de->size = 0; 661 out_free: 662 __putname(uname); 663 return err; 664 } 665 666 static int vfat_add_entry(struct inode *dir, const struct qstr *qname, 667 int is_dir, int cluster, struct timespec *ts, 668 struct fat_slot_info *sinfo) 669 { 670 struct msdos_dir_slot *slots; 671 unsigned int len; 672 int err, nr_slots; 673 674 len = vfat_striptail_len(qname); 675 if (len == 0) 676 return -ENOENT; 677 678 slots = kmalloc(sizeof(*slots) * MSDOS_SLOTS, GFP_NOFS); 679 if (slots == NULL) 680 return -ENOMEM; 681 682 err = vfat_build_slots(dir, qname->name, len, is_dir, cluster, ts, 683 slots, &nr_slots); 684 if (err) 685 goto cleanup; 686 687 err = fat_add_entries(dir, slots, nr_slots, sinfo); 688 if (err) 689 goto cleanup; 690 691 /* update timestamp */ 692 dir->i_ctime = dir->i_mtime = dir->i_atime = *ts; 693 if (IS_DIRSYNC(dir)) 694 (void)fat_sync_inode(dir); 695 else 696 mark_inode_dirty(dir); 697 cleanup: 698 kfree(slots); 699 return err; 700 } 701 702 static int vfat_find(struct inode *dir, const struct qstr *qname, 703 struct fat_slot_info *sinfo) 704 { 705 unsigned int len = vfat_striptail_len(qname); 706 if (len == 0) 707 return -ENOENT; 708 return fat_search_long(dir, qname->name, len, sinfo); 709 } 710 711 /* 712 * (nfsd's) anonymous disconnected dentry? 713 * NOTE: !IS_ROOT() is not anonymous (I.e. d_splice_alias() did the job). 714 */ 715 static int vfat_d_anon_disconn(struct dentry *dentry) 716 { 717 return IS_ROOT(dentry) && (dentry->d_flags & DCACHE_DISCONNECTED); 718 } 719 720 static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry, 721 unsigned int flags) 722 { 723 struct super_block *sb = dir->i_sb; 724 struct fat_slot_info sinfo; 725 struct inode *inode; 726 struct dentry *alias; 727 int err; 728 729 mutex_lock(&MSDOS_SB(sb)->s_lock); 730 731 err = vfat_find(dir, &dentry->d_name, &sinfo); 732 if (err) { 733 if (err == -ENOENT) { 734 inode = NULL; 735 goto out; 736 } 737 goto error; 738 } 739 740 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); 741 brelse(sinfo.bh); 742 if (IS_ERR(inode)) { 743 err = PTR_ERR(inode); 744 goto error; 745 } 746 747 alias = d_find_alias(inode); 748 /* 749 * Checking "alias->d_parent == dentry->d_parent" to make sure 750 * FS is not corrupted (especially double linked dir). 751 */ 752 if (alias && alias->d_parent == dentry->d_parent && 753 !vfat_d_anon_disconn(alias)) { 754 /* 755 * This inode has non anonymous-DCACHE_DISCONNECTED 756 * dentry. This means, the user did ->lookup() by an 757 * another name (longname vs 8.3 alias of it) in past. 758 * 759 * Switch to new one for reason of locality if possible. 760 */ 761 BUG_ON(d_unhashed(alias)); 762 if (!S_ISDIR(inode->i_mode)) 763 d_move(alias, dentry); 764 iput(inode); 765 mutex_unlock(&MSDOS_SB(sb)->s_lock); 766 return alias; 767 } else 768 dput(alias); 769 770 out: 771 mutex_unlock(&MSDOS_SB(sb)->s_lock); 772 if (!inode) 773 vfat_d_version_set(dentry, dir->i_version); 774 return d_splice_alias(inode, dentry); 775 error: 776 mutex_unlock(&MSDOS_SB(sb)->s_lock); 777 return ERR_PTR(err); 778 } 779 780 static int vfat_create(struct inode *dir, struct dentry *dentry, umode_t mode, 781 bool excl) 782 { 783 struct super_block *sb = dir->i_sb; 784 struct inode *inode; 785 struct fat_slot_info sinfo; 786 struct timespec ts; 787 int err; 788 789 mutex_lock(&MSDOS_SB(sb)->s_lock); 790 791 ts = CURRENT_TIME_SEC; 792 err = vfat_add_entry(dir, &dentry->d_name, 0, 0, &ts, &sinfo); 793 if (err) 794 goto out; 795 dir->i_version++; 796 797 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); 798 brelse(sinfo.bh); 799 if (IS_ERR(inode)) { 800 err = PTR_ERR(inode); 801 goto out; 802 } 803 inode->i_version++; 804 inode->i_mtime = inode->i_atime = inode->i_ctime = ts; 805 /* timestamp is already written, so mark_inode_dirty() is unneeded. */ 806 807 d_instantiate(dentry, inode); 808 out: 809 mutex_unlock(&MSDOS_SB(sb)->s_lock); 810 return err; 811 } 812 813 static int vfat_rmdir(struct inode *dir, struct dentry *dentry) 814 { 815 struct inode *inode = d_inode(dentry); 816 struct super_block *sb = dir->i_sb; 817 struct fat_slot_info sinfo; 818 int err; 819 820 mutex_lock(&MSDOS_SB(sb)->s_lock); 821 822 err = fat_dir_empty(inode); 823 if (err) 824 goto out; 825 err = vfat_find(dir, &dentry->d_name, &sinfo); 826 if (err) 827 goto out; 828 829 err = fat_remove_entries(dir, &sinfo); /* and releases bh */ 830 if (err) 831 goto out; 832 drop_nlink(dir); 833 834 clear_nlink(inode); 835 inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC; 836 fat_detach(inode); 837 vfat_d_version_set(dentry, dir->i_version); 838 out: 839 mutex_unlock(&MSDOS_SB(sb)->s_lock); 840 841 return err; 842 } 843 844 static int vfat_unlink(struct inode *dir, struct dentry *dentry) 845 { 846 struct inode *inode = d_inode(dentry); 847 struct super_block *sb = dir->i_sb; 848 struct fat_slot_info sinfo; 849 int err; 850 851 mutex_lock(&MSDOS_SB(sb)->s_lock); 852 853 err = vfat_find(dir, &dentry->d_name, &sinfo); 854 if (err) 855 goto out; 856 857 err = fat_remove_entries(dir, &sinfo); /* and releases bh */ 858 if (err) 859 goto out; 860 clear_nlink(inode); 861 inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC; 862 fat_detach(inode); 863 vfat_d_version_set(dentry, dir->i_version); 864 out: 865 mutex_unlock(&MSDOS_SB(sb)->s_lock); 866 867 return err; 868 } 869 870 static int vfat_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) 871 { 872 struct super_block *sb = dir->i_sb; 873 struct inode *inode; 874 struct fat_slot_info sinfo; 875 struct timespec ts; 876 int err, cluster; 877 878 mutex_lock(&MSDOS_SB(sb)->s_lock); 879 880 ts = CURRENT_TIME_SEC; 881 cluster = fat_alloc_new_dir(dir, &ts); 882 if (cluster < 0) { 883 err = cluster; 884 goto out; 885 } 886 err = vfat_add_entry(dir, &dentry->d_name, 1, cluster, &ts, &sinfo); 887 if (err) 888 goto out_free; 889 dir->i_version++; 890 inc_nlink(dir); 891 892 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); 893 brelse(sinfo.bh); 894 if (IS_ERR(inode)) { 895 err = PTR_ERR(inode); 896 /* the directory was completed, just return a error */ 897 goto out; 898 } 899 inode->i_version++; 900 set_nlink(inode, 2); 901 inode->i_mtime = inode->i_atime = inode->i_ctime = ts; 902 /* timestamp is already written, so mark_inode_dirty() is unneeded. */ 903 904 d_instantiate(dentry, inode); 905 906 mutex_unlock(&MSDOS_SB(sb)->s_lock); 907 return 0; 908 909 out_free: 910 fat_free_clusters(dir, cluster); 911 out: 912 mutex_unlock(&MSDOS_SB(sb)->s_lock); 913 return err; 914 } 915 916 static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry, 917 struct inode *new_dir, struct dentry *new_dentry) 918 { 919 struct buffer_head *dotdot_bh; 920 struct msdos_dir_entry *dotdot_de; 921 struct inode *old_inode, *new_inode; 922 struct fat_slot_info old_sinfo, sinfo; 923 struct timespec ts; 924 loff_t new_i_pos; 925 int err, is_dir, update_dotdot, corrupt = 0; 926 struct super_block *sb = old_dir->i_sb; 927 928 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL; 929 old_inode = d_inode(old_dentry); 930 new_inode = d_inode(new_dentry); 931 mutex_lock(&MSDOS_SB(sb)->s_lock); 932 err = vfat_find(old_dir, &old_dentry->d_name, &old_sinfo); 933 if (err) 934 goto out; 935 936 is_dir = S_ISDIR(old_inode->i_mode); 937 update_dotdot = (is_dir && old_dir != new_dir); 938 if (update_dotdot) { 939 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de)) { 940 err = -EIO; 941 goto out; 942 } 943 } 944 945 ts = CURRENT_TIME_SEC; 946 if (new_inode) { 947 if (is_dir) { 948 err = fat_dir_empty(new_inode); 949 if (err) 950 goto out; 951 } 952 new_i_pos = MSDOS_I(new_inode)->i_pos; 953 fat_detach(new_inode); 954 } else { 955 err = vfat_add_entry(new_dir, &new_dentry->d_name, is_dir, 0, 956 &ts, &sinfo); 957 if (err) 958 goto out; 959 new_i_pos = sinfo.i_pos; 960 } 961 new_dir->i_version++; 962 963 fat_detach(old_inode); 964 fat_attach(old_inode, new_i_pos); 965 if (IS_DIRSYNC(new_dir)) { 966 err = fat_sync_inode(old_inode); 967 if (err) 968 goto error_inode; 969 } else 970 mark_inode_dirty(old_inode); 971 972 if (update_dotdot) { 973 fat_set_start(dotdot_de, MSDOS_I(new_dir)->i_logstart); 974 mark_buffer_dirty_inode(dotdot_bh, old_inode); 975 if (IS_DIRSYNC(new_dir)) { 976 err = sync_dirty_buffer(dotdot_bh); 977 if (err) 978 goto error_dotdot; 979 } 980 drop_nlink(old_dir); 981 if (!new_inode) 982 inc_nlink(new_dir); 983 } 984 985 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */ 986 old_sinfo.bh = NULL; 987 if (err) 988 goto error_dotdot; 989 old_dir->i_version++; 990 old_dir->i_ctime = old_dir->i_mtime = ts; 991 if (IS_DIRSYNC(old_dir)) 992 (void)fat_sync_inode(old_dir); 993 else 994 mark_inode_dirty(old_dir); 995 996 if (new_inode) { 997 drop_nlink(new_inode); 998 if (is_dir) 999 drop_nlink(new_inode); 1000 new_inode->i_ctime = ts; 1001 } 1002 out: 1003 brelse(sinfo.bh); 1004 brelse(dotdot_bh); 1005 brelse(old_sinfo.bh); 1006 mutex_unlock(&MSDOS_SB(sb)->s_lock); 1007 1008 return err; 1009 1010 error_dotdot: 1011 /* data cluster is shared, serious corruption */ 1012 corrupt = 1; 1013 1014 if (update_dotdot) { 1015 fat_set_start(dotdot_de, MSDOS_I(old_dir)->i_logstart); 1016 mark_buffer_dirty_inode(dotdot_bh, old_inode); 1017 corrupt |= sync_dirty_buffer(dotdot_bh); 1018 } 1019 error_inode: 1020 fat_detach(old_inode); 1021 fat_attach(old_inode, old_sinfo.i_pos); 1022 if (new_inode) { 1023 fat_attach(new_inode, new_i_pos); 1024 if (corrupt) 1025 corrupt |= fat_sync_inode(new_inode); 1026 } else { 1027 /* 1028 * If new entry was not sharing the data cluster, it 1029 * shouldn't be serious corruption. 1030 */ 1031 int err2 = fat_remove_entries(new_dir, &sinfo); 1032 if (corrupt) 1033 corrupt |= err2; 1034 sinfo.bh = NULL; 1035 } 1036 if (corrupt < 0) { 1037 fat_fs_error(new_dir->i_sb, 1038 "%s: Filesystem corrupted (i_pos %lld)", 1039 __func__, sinfo.i_pos); 1040 } 1041 goto out; 1042 } 1043 1044 static const struct inode_operations vfat_dir_inode_operations = { 1045 .create = vfat_create, 1046 .lookup = vfat_lookup, 1047 .unlink = vfat_unlink, 1048 .mkdir = vfat_mkdir, 1049 .rmdir = vfat_rmdir, 1050 .rename = vfat_rename, 1051 .setattr = fat_setattr, 1052 .getattr = fat_getattr, 1053 }; 1054 1055 static void setup(struct super_block *sb) 1056 { 1057 MSDOS_SB(sb)->dir_ops = &vfat_dir_inode_operations; 1058 if (MSDOS_SB(sb)->options.name_check != 's') 1059 sb->s_d_op = &vfat_ci_dentry_ops; 1060 else 1061 sb->s_d_op = &vfat_dentry_ops; 1062 } 1063 1064 static int vfat_fill_super(struct super_block *sb, void *data, int silent) 1065 { 1066 return fat_fill_super(sb, data, silent, 1, setup); 1067 } 1068 1069 static struct dentry *vfat_mount(struct file_system_type *fs_type, 1070 int flags, const char *dev_name, 1071 void *data) 1072 { 1073 return mount_bdev(fs_type, flags, dev_name, data, vfat_fill_super); 1074 } 1075 1076 static struct file_system_type vfat_fs_type = { 1077 .owner = THIS_MODULE, 1078 .name = "vfat", 1079 .mount = vfat_mount, 1080 .kill_sb = kill_block_super, 1081 .fs_flags = FS_REQUIRES_DEV, 1082 }; 1083 MODULE_ALIAS_FS("vfat"); 1084 1085 static int __init init_vfat_fs(void) 1086 { 1087 return register_filesystem(&vfat_fs_type); 1088 } 1089 1090 static void __exit exit_vfat_fs(void) 1091 { 1092 unregister_filesystem(&vfat_fs_type); 1093 } 1094 1095 MODULE_LICENSE("GPL"); 1096 MODULE_DESCRIPTION("VFAT filesystem support"); 1097 MODULE_AUTHOR("Gordon Chaffee"); 1098 1099 module_init(init_vfat_fs) 1100 module_exit(exit_vfat_fs) 1101