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/jiffies.h> 20 #include <linux/ctype.h> 21 #include <linux/slab.h> 22 #include <linux/smp_lock.h> 23 #include <linux/buffer_head.h> 24 #include <linux/namei.h> 25 #include "fat.h" 26 27 static int vfat_revalidate(struct dentry *dentry, struct nameidata *nd) 28 { 29 int ret = 1; 30 31 if (!dentry->d_inode && 32 nd && !(nd->flags & LOOKUP_CONTINUE) && (nd->flags & LOOKUP_CREATE)) 33 /* 34 * negative dentry is dropped, in order to make sure 35 * to use the name which a user desires if this is 36 * create path. 37 */ 38 ret = 0; 39 else { 40 spin_lock(&dentry->d_lock); 41 if (dentry->d_time != dentry->d_parent->d_inode->i_version) 42 ret = 0; 43 spin_unlock(&dentry->d_lock); 44 } 45 return ret; 46 } 47 48 /* returns the length of a struct qstr, ignoring trailing dots */ 49 static unsigned int vfat_striptail_len(struct qstr *qstr) 50 { 51 unsigned int len = qstr->len; 52 53 while (len && qstr->name[len - 1] == '.') 54 len--; 55 return len; 56 } 57 58 /* 59 * Compute the hash for the vfat name corresponding to the dentry. 60 * Note: if the name is invalid, we leave the hash code unchanged so 61 * that the existing dentry can be used. The vfat fs routines will 62 * return ENOENT or EINVAL as appropriate. 63 */ 64 static int vfat_hash(struct dentry *dentry, struct qstr *qstr) 65 { 66 qstr->hash = full_name_hash(qstr->name, vfat_striptail_len(qstr)); 67 return 0; 68 } 69 70 /* 71 * Compute the hash for the vfat name corresponding to the dentry. 72 * Note: if the name is invalid, we leave the hash code unchanged so 73 * that the existing dentry can be used. The vfat fs routines will 74 * return ENOENT or EINVAL as appropriate. 75 */ 76 static int vfat_hashi(struct dentry *dentry, struct qstr *qstr) 77 { 78 struct nls_table *t = MSDOS_SB(dentry->d_inode->i_sb)->nls_io; 79 const unsigned char *name; 80 unsigned int len; 81 unsigned long hash; 82 83 name = qstr->name; 84 len = vfat_striptail_len(qstr); 85 86 hash = init_name_hash(); 87 while (len--) 88 hash = partial_name_hash(nls_tolower(t, *name++), hash); 89 qstr->hash = end_name_hash(hash); 90 91 return 0; 92 } 93 94 /* 95 * Case insensitive compare of two vfat names. 96 */ 97 static int vfat_cmpi(struct dentry *dentry, struct qstr *a, struct qstr *b) 98 { 99 struct nls_table *t = MSDOS_SB(dentry->d_inode->i_sb)->nls_io; 100 unsigned int alen, blen; 101 102 /* A filename cannot end in '.' or we treat it like it has none */ 103 alen = vfat_striptail_len(a); 104 blen = vfat_striptail_len(b); 105 if (alen == blen) { 106 if (nls_strnicmp(t, a->name, b->name, alen) == 0) 107 return 0; 108 } 109 return 1; 110 } 111 112 /* 113 * Case sensitive compare of two vfat names. 114 */ 115 static int vfat_cmp(struct dentry *dentry, struct qstr *a, struct qstr *b) 116 { 117 unsigned int alen, blen; 118 119 /* A filename cannot end in '.' or we treat it like it has none */ 120 alen = vfat_striptail_len(a); 121 blen = vfat_striptail_len(b); 122 if (alen == blen) { 123 if (strncmp(a->name, b->name, alen) == 0) 124 return 0; 125 } 126 return 1; 127 } 128 129 static struct dentry_operations vfat_dentry_ops[4] = { 130 { 131 .d_hash = vfat_hashi, 132 .d_compare = vfat_cmpi, 133 }, 134 { 135 .d_revalidate = vfat_revalidate, 136 .d_hash = vfat_hashi, 137 .d_compare = vfat_cmpi, 138 }, 139 { 140 .d_hash = vfat_hash, 141 .d_compare = vfat_cmp, 142 }, 143 { 144 .d_revalidate = vfat_revalidate, 145 .d_hash = vfat_hash, 146 .d_compare = vfat_cmp, 147 } 148 }; 149 150 /* Characters that are undesirable in an MS-DOS file name */ 151 152 static inline wchar_t vfat_bad_char(wchar_t w) 153 { 154 return (w < 0x0020) 155 || (w == '*') || (w == '?') || (w == '<') || (w == '>') 156 || (w == '|') || (w == '"') || (w == ':') || (w == '/') 157 || (w == '\\'); 158 } 159 160 static inline wchar_t vfat_replace_char(wchar_t w) 161 { 162 return (w == '[') || (w == ']') || (w == ';') || (w == ',') 163 || (w == '+') || (w == '='); 164 } 165 166 static wchar_t vfat_skip_char(wchar_t w) 167 { 168 return (w == '.') || (w == ' '); 169 } 170 171 static inline int vfat_is_used_badchars(const wchar_t *s, int len) 172 { 173 int i; 174 175 for (i = 0; i < len; i++) 176 if (vfat_bad_char(s[i])) 177 return -EINVAL; 178 179 if (s[i - 1] == ' ') /* last character cannot be space */ 180 return -EINVAL; 181 182 return 0; 183 } 184 185 static int vfat_find_form(struct inode *dir, unsigned char *name) 186 { 187 struct fat_slot_info sinfo; 188 int err = fat_scan(dir, name, &sinfo); 189 if (err) 190 return -ENOENT; 191 brelse(sinfo.bh); 192 return 0; 193 } 194 195 /* 196 * 1) Valid characters for the 8.3 format alias are any combination of 197 * letters, uppercase alphabets, digits, any of the 198 * following special characters: 199 * $ % ' ` - @ { } ~ ! # ( ) & _ ^ 200 * In this case Longfilename is not stored in disk. 201 * 202 * WinNT's Extension: 203 * File name and extension name is contain uppercase/lowercase 204 * only. And it is expressed by CASE_LOWER_BASE and CASE_LOWER_EXT. 205 * 206 * 2) File name is 8.3 format, but it contain the uppercase and 207 * lowercase char, muliti bytes char, etc. In this case numtail is not 208 * added, but Longfilename is stored. 209 * 210 * 3) When the one except for the above, or the following special 211 * character are contained: 212 * . [ ] ; , + = 213 * numtail is added, and Longfilename must be stored in disk . 214 */ 215 struct shortname_info { 216 unsigned char lower:1, 217 upper:1, 218 valid:1; 219 }; 220 #define INIT_SHORTNAME_INFO(x) do { \ 221 (x)->lower = 1; \ 222 (x)->upper = 1; \ 223 (x)->valid = 1; \ 224 } while (0) 225 226 static inline int to_shortname_char(struct nls_table *nls, 227 unsigned char *buf, int buf_size, 228 wchar_t *src, struct shortname_info *info) 229 { 230 int len; 231 232 if (vfat_skip_char(*src)) { 233 info->valid = 0; 234 return 0; 235 } 236 if (vfat_replace_char(*src)) { 237 info->valid = 0; 238 buf[0] = '_'; 239 return 1; 240 } 241 242 len = nls->uni2char(*src, buf, buf_size); 243 if (len <= 0) { 244 info->valid = 0; 245 buf[0] = '_'; 246 len = 1; 247 } else if (len == 1) { 248 unsigned char prev = buf[0]; 249 250 if (buf[0] >= 0x7F) { 251 info->lower = 0; 252 info->upper = 0; 253 } 254 255 buf[0] = nls_toupper(nls, buf[0]); 256 if (isalpha(buf[0])) { 257 if (buf[0] == prev) 258 info->lower = 0; 259 else 260 info->upper = 0; 261 } 262 } else { 263 info->lower = 0; 264 info->upper = 0; 265 } 266 267 return len; 268 } 269 270 /* 271 * Given a valid longname, create a unique shortname. Make sure the 272 * shortname does not exist 273 * Returns negative number on error, 0 for a normal 274 * return, and 1 for valid shortname 275 */ 276 static int vfat_create_shortname(struct inode *dir, struct nls_table *nls, 277 wchar_t *uname, int ulen, 278 unsigned char *name_res, unsigned char *lcase) 279 { 280 struct fat_mount_options *opts = &MSDOS_SB(dir->i_sb)->options; 281 wchar_t *ip, *ext_start, *end, *name_start; 282 unsigned char base[9], ext[4], buf[8], *p; 283 unsigned char charbuf[NLS_MAX_CHARSET_SIZE]; 284 int chl, chi; 285 int sz = 0, extlen, baselen, i, numtail_baselen, numtail2_baselen; 286 int is_shortname; 287 struct shortname_info base_info, ext_info; 288 289 is_shortname = 1; 290 INIT_SHORTNAME_INFO(&base_info); 291 INIT_SHORTNAME_INFO(&ext_info); 292 293 /* Now, we need to create a shortname from the long name */ 294 ext_start = end = &uname[ulen]; 295 while (--ext_start >= uname) { 296 if (*ext_start == 0x002E) { /* is `.' */ 297 if (ext_start == end - 1) { 298 sz = ulen; 299 ext_start = NULL; 300 } 301 break; 302 } 303 } 304 305 if (ext_start == uname - 1) { 306 sz = ulen; 307 ext_start = NULL; 308 } else if (ext_start) { 309 /* 310 * Names which start with a dot could be just 311 * an extension eg. "...test". In this case Win95 312 * uses the extension as the name and sets no extension. 313 */ 314 name_start = &uname[0]; 315 while (name_start < ext_start) { 316 if (!vfat_skip_char(*name_start)) 317 break; 318 name_start++; 319 } 320 if (name_start != ext_start) { 321 sz = ext_start - uname; 322 ext_start++; 323 } else { 324 sz = ulen; 325 ext_start = NULL; 326 } 327 } 328 329 numtail_baselen = 6; 330 numtail2_baselen = 2; 331 for (baselen = i = 0, p = base, ip = uname; i < sz; i++, ip++) { 332 chl = to_shortname_char(nls, charbuf, sizeof(charbuf), 333 ip, &base_info); 334 if (chl == 0) 335 continue; 336 337 if (baselen < 2 && (baselen + chl) > 2) 338 numtail2_baselen = baselen; 339 if (baselen < 6 && (baselen + chl) > 6) 340 numtail_baselen = baselen; 341 for (chi = 0; chi < chl; chi++) { 342 *p++ = charbuf[chi]; 343 baselen++; 344 if (baselen >= 8) 345 break; 346 } 347 if (baselen >= 8) { 348 if ((chi < chl - 1) || (ip + 1) - uname < sz) 349 is_shortname = 0; 350 break; 351 } 352 } 353 if (baselen == 0) { 354 return -EINVAL; 355 } 356 357 extlen = 0; 358 if (ext_start) { 359 for (p = ext, ip = ext_start; extlen < 3 && ip < end; ip++) { 360 chl = to_shortname_char(nls, charbuf, sizeof(charbuf), 361 ip, &ext_info); 362 if (chl == 0) 363 continue; 364 365 if ((extlen + chl) > 3) { 366 is_shortname = 0; 367 break; 368 } 369 for (chi = 0; chi < chl; chi++) { 370 *p++ = charbuf[chi]; 371 extlen++; 372 } 373 if (extlen >= 3) { 374 if (ip + 1 != end) 375 is_shortname = 0; 376 break; 377 } 378 } 379 } 380 ext[extlen] = '\0'; 381 base[baselen] = '\0'; 382 383 /* Yes, it can happen. ".\xe5" would do it. */ 384 if (base[0] == DELETED_FLAG) 385 base[0] = 0x05; 386 387 /* OK, at this point we know that base is not longer than 8 symbols, 388 * ext is not longer than 3, base is nonempty, both don't contain 389 * any bad symbols (lowercase transformed to uppercase). 390 */ 391 392 memset(name_res, ' ', MSDOS_NAME); 393 memcpy(name_res, base, baselen); 394 memcpy(name_res + 8, ext, extlen); 395 *lcase = 0; 396 if (is_shortname && base_info.valid && ext_info.valid) { 397 if (vfat_find_form(dir, name_res) == 0) 398 return -EEXIST; 399 400 if (opts->shortname & VFAT_SFN_CREATE_WIN95) { 401 return (base_info.upper && ext_info.upper); 402 } else if (opts->shortname & VFAT_SFN_CREATE_WINNT) { 403 if ((base_info.upper || base_info.lower) && 404 (ext_info.upper || ext_info.lower)) { 405 if (!base_info.upper && base_info.lower) 406 *lcase |= CASE_LOWER_BASE; 407 if (!ext_info.upper && ext_info.lower) 408 *lcase |= CASE_LOWER_EXT; 409 return 1; 410 } 411 return 0; 412 } else { 413 BUG(); 414 } 415 } 416 417 if (opts->numtail == 0) 418 if (vfat_find_form(dir, name_res) < 0) 419 return 0; 420 421 /* 422 * Try to find a unique extension. This used to 423 * iterate through all possibilities sequentially, 424 * but that gave extremely bad performance. Windows 425 * only tries a few cases before using random 426 * values for part of the base. 427 */ 428 429 if (baselen > 6) { 430 baselen = numtail_baselen; 431 name_res[7] = ' '; 432 } 433 name_res[baselen] = '~'; 434 for (i = 1; i < 10; i++) { 435 name_res[baselen + 1] = i + '0'; 436 if (vfat_find_form(dir, name_res) < 0) 437 return 0; 438 } 439 440 i = jiffies & 0xffff; 441 sz = (jiffies >> 16) & 0x7; 442 if (baselen > 2) { 443 baselen = numtail2_baselen; 444 name_res[7] = ' '; 445 } 446 name_res[baselen + 4] = '~'; 447 name_res[baselen + 5] = '1' + sz; 448 while (1) { 449 sprintf(buf, "%04X", i); 450 memcpy(&name_res[baselen], buf, 4); 451 if (vfat_find_form(dir, name_res) < 0) 452 break; 453 i -= 11; 454 } 455 return 0; 456 } 457 458 /* Translate a string, including coded sequences into Unicode */ 459 static int 460 xlate_to_uni(const unsigned char *name, int len, unsigned char *outname, 461 int *longlen, int *outlen, int escape, int utf8, 462 struct nls_table *nls) 463 { 464 const unsigned char *ip; 465 unsigned char nc; 466 unsigned char *op; 467 unsigned int ec; 468 int i, k, fill; 469 int charlen; 470 471 if (utf8) { 472 int name_len = strlen(name); 473 474 *outlen = utf8_mbstowcs((wchar_t *)outname, name, PATH_MAX); 475 476 /* 477 * We stripped '.'s before and set len appropriately, 478 * but utf8_mbstowcs doesn't care about len 479 */ 480 *outlen -= (name_len - len); 481 482 if (*outlen > 255) 483 return -ENAMETOOLONG; 484 485 op = &outname[*outlen * sizeof(wchar_t)]; 486 } else { 487 if (nls) { 488 for (i = 0, ip = name, op = outname, *outlen = 0; 489 i < len && *outlen <= 255; 490 *outlen += 1) 491 { 492 if (escape && (*ip == ':')) { 493 if (i > len - 5) 494 return -EINVAL; 495 ec = 0; 496 for (k = 1; k < 5; k++) { 497 nc = ip[k]; 498 ec <<= 4; 499 if (nc >= '0' && nc <= '9') { 500 ec |= nc - '0'; 501 continue; 502 } 503 if (nc >= 'a' && nc <= 'f') { 504 ec |= nc - ('a' - 10); 505 continue; 506 } 507 if (nc >= 'A' && nc <= 'F') { 508 ec |= nc - ('A' - 10); 509 continue; 510 } 511 return -EINVAL; 512 } 513 *op++ = ec & 0xFF; 514 *op++ = ec >> 8; 515 ip += 5; 516 i += 5; 517 } else { 518 if ((charlen = nls->char2uni(ip, len - i, (wchar_t *)op)) < 0) 519 return -EINVAL; 520 ip += charlen; 521 i += charlen; 522 op += 2; 523 } 524 } 525 if (i < len) 526 return -ENAMETOOLONG; 527 } else { 528 for (i = 0, ip = name, op = outname, *outlen = 0; 529 i < len && *outlen <= 255; 530 i++, *outlen += 1) 531 { 532 *op++ = *ip++; 533 *op++ = 0; 534 } 535 if (i < len) 536 return -ENAMETOOLONG; 537 } 538 } 539 540 *longlen = *outlen; 541 if (*outlen % 13) { 542 *op++ = 0; 543 *op++ = 0; 544 *outlen += 1; 545 if (*outlen % 13) { 546 fill = 13 - (*outlen % 13); 547 for (i = 0; i < fill; i++) { 548 *op++ = 0xff; 549 *op++ = 0xff; 550 } 551 *outlen += fill; 552 } 553 } 554 555 return 0; 556 } 557 558 static int vfat_build_slots(struct inode *dir, const unsigned char *name, 559 int len, int is_dir, int cluster, 560 struct timespec *ts, 561 struct msdos_dir_slot *slots, int *nr_slots) 562 { 563 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb); 564 struct fat_mount_options *opts = &sbi->options; 565 struct msdos_dir_slot *ps; 566 struct msdos_dir_entry *de; 567 unsigned char cksum, lcase; 568 unsigned char msdos_name[MSDOS_NAME]; 569 wchar_t *uname; 570 __le16 time, date; 571 int err, ulen, usize, i; 572 loff_t offset; 573 574 *nr_slots = 0; 575 576 uname = __getname(); 577 if (!uname) 578 return -ENOMEM; 579 580 err = xlate_to_uni(name, len, (unsigned char *)uname, &ulen, &usize, 581 opts->unicode_xlate, opts->utf8, sbi->nls_io); 582 if (err) 583 goto out_free; 584 585 err = vfat_is_used_badchars(uname, ulen); 586 if (err) 587 goto out_free; 588 589 err = vfat_create_shortname(dir, sbi->nls_disk, uname, ulen, 590 msdos_name, &lcase); 591 if (err < 0) 592 goto out_free; 593 else if (err == 1) { 594 de = (struct msdos_dir_entry *)slots; 595 err = 0; 596 goto shortname; 597 } 598 599 /* build the entry of long file name */ 600 cksum = fat_checksum(msdos_name); 601 602 *nr_slots = usize / 13; 603 for (ps = slots, i = *nr_slots; i > 0; i--, ps++) { 604 ps->id = i; 605 ps->attr = ATTR_EXT; 606 ps->reserved = 0; 607 ps->alias_checksum = cksum; 608 ps->start = 0; 609 offset = (i - 1) * 13; 610 fatwchar_to16(ps->name0_4, uname + offset, 5); 611 fatwchar_to16(ps->name5_10, uname + offset + 5, 6); 612 fatwchar_to16(ps->name11_12, uname + offset + 11, 2); 613 } 614 slots[0].id |= 0x40; 615 de = (struct msdos_dir_entry *)ps; 616 617 shortname: 618 /* build the entry of 8.3 alias name */ 619 (*nr_slots)++; 620 memcpy(de->name, msdos_name, MSDOS_NAME); 621 de->attr = is_dir ? ATTR_DIR : ATTR_ARCH; 622 de->lcase = lcase; 623 fat_date_unix2dos(ts->tv_sec, &time, &date, sbi->options.tz_utc); 624 de->time = de->ctime = time; 625 de->date = de->cdate = de->adate = date; 626 de->ctime_cs = 0; 627 de->start = cpu_to_le16(cluster); 628 de->starthi = cpu_to_le16(cluster >> 16); 629 de->size = 0; 630 out_free: 631 __putname(uname); 632 return err; 633 } 634 635 static int vfat_add_entry(struct inode *dir, struct qstr *qname, int is_dir, 636 int cluster, struct timespec *ts, 637 struct fat_slot_info *sinfo) 638 { 639 struct msdos_dir_slot *slots; 640 unsigned int len; 641 int err, nr_slots; 642 643 len = vfat_striptail_len(qname); 644 if (len == 0) 645 return -ENOENT; 646 647 slots = kmalloc(sizeof(*slots) * MSDOS_SLOTS, GFP_NOFS); 648 if (slots == NULL) 649 return -ENOMEM; 650 651 err = vfat_build_slots(dir, qname->name, len, is_dir, cluster, ts, 652 slots, &nr_slots); 653 if (err) 654 goto cleanup; 655 656 err = fat_add_entries(dir, slots, nr_slots, sinfo); 657 if (err) 658 goto cleanup; 659 660 /* update timestamp */ 661 dir->i_ctime = dir->i_mtime = dir->i_atime = *ts; 662 if (IS_DIRSYNC(dir)) 663 (void)fat_sync_inode(dir); 664 else 665 mark_inode_dirty(dir); 666 cleanup: 667 kfree(slots); 668 return err; 669 } 670 671 static int vfat_find(struct inode *dir, struct qstr *qname, 672 struct fat_slot_info *sinfo) 673 { 674 unsigned int len = vfat_striptail_len(qname); 675 if (len == 0) 676 return -ENOENT; 677 return fat_search_long(dir, qname->name, len, sinfo); 678 } 679 680 static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry, 681 struct nameidata *nd) 682 { 683 struct super_block *sb = dir->i_sb; 684 struct fat_slot_info sinfo; 685 struct inode *inode = NULL; 686 struct dentry *alias; 687 int err, table; 688 689 lock_super(sb); 690 table = (MSDOS_SB(sb)->options.name_check == 's') ? 2 : 0; 691 dentry->d_op = &vfat_dentry_ops[table]; 692 693 err = vfat_find(dir, &dentry->d_name, &sinfo); 694 if (err) { 695 table++; 696 goto error; 697 } 698 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); 699 brelse(sinfo.bh); 700 if (IS_ERR(inode)) { 701 unlock_super(sb); 702 return ERR_CAST(inode); 703 } 704 alias = d_find_alias(inode); 705 if (alias) { 706 if (d_invalidate(alias) == 0) 707 dput(alias); 708 else { 709 iput(inode); 710 unlock_super(sb); 711 return alias; 712 } 713 714 } 715 error: 716 unlock_super(sb); 717 dentry->d_op = &vfat_dentry_ops[table]; 718 dentry->d_time = dentry->d_parent->d_inode->i_version; 719 dentry = d_splice_alias(inode, dentry); 720 if (dentry) { 721 dentry->d_op = &vfat_dentry_ops[table]; 722 dentry->d_time = dentry->d_parent->d_inode->i_version; 723 } 724 return dentry; 725 } 726 727 static int vfat_create(struct inode *dir, struct dentry *dentry, int mode, 728 struct nameidata *nd) 729 { 730 struct super_block *sb = dir->i_sb; 731 struct inode *inode; 732 struct fat_slot_info sinfo; 733 struct timespec ts; 734 int err; 735 736 lock_super(sb); 737 738 ts = CURRENT_TIME_SEC; 739 err = vfat_add_entry(dir, &dentry->d_name, 0, 0, &ts, &sinfo); 740 if (err) 741 goto out; 742 dir->i_version++; 743 744 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); 745 brelse(sinfo.bh); 746 if (IS_ERR(inode)) { 747 err = PTR_ERR(inode); 748 goto out; 749 } 750 inode->i_version++; 751 inode->i_mtime = inode->i_atime = inode->i_ctime = ts; 752 /* timestamp is already written, so mark_inode_dirty() is unneeded. */ 753 754 dentry->d_time = dentry->d_parent->d_inode->i_version; 755 d_instantiate(dentry, inode); 756 out: 757 unlock_super(sb); 758 return err; 759 } 760 761 static int vfat_rmdir(struct inode *dir, struct dentry *dentry) 762 { 763 struct inode *inode = dentry->d_inode; 764 struct super_block *sb = dir->i_sb; 765 struct fat_slot_info sinfo; 766 int err; 767 768 lock_super(sb); 769 770 err = fat_dir_empty(inode); 771 if (err) 772 goto out; 773 err = vfat_find(dir, &dentry->d_name, &sinfo); 774 if (err) 775 goto out; 776 777 err = fat_remove_entries(dir, &sinfo); /* and releases bh */ 778 if (err) 779 goto out; 780 drop_nlink(dir); 781 782 clear_nlink(inode); 783 inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC; 784 fat_detach(inode); 785 out: 786 unlock_super(sb); 787 788 return err; 789 } 790 791 static int vfat_unlink(struct inode *dir, struct dentry *dentry) 792 { 793 struct inode *inode = dentry->d_inode; 794 struct super_block *sb = dir->i_sb; 795 struct fat_slot_info sinfo; 796 int err; 797 798 lock_super(sb); 799 800 err = vfat_find(dir, &dentry->d_name, &sinfo); 801 if (err) 802 goto out; 803 804 err = fat_remove_entries(dir, &sinfo); /* and releases bh */ 805 if (err) 806 goto out; 807 clear_nlink(inode); 808 inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC; 809 fat_detach(inode); 810 out: 811 unlock_super(sb); 812 813 return err; 814 } 815 816 static int vfat_mkdir(struct inode *dir, struct dentry *dentry, int mode) 817 { 818 struct super_block *sb = dir->i_sb; 819 struct inode *inode; 820 struct fat_slot_info sinfo; 821 struct timespec ts; 822 int err, cluster; 823 824 lock_super(sb); 825 826 ts = CURRENT_TIME_SEC; 827 cluster = fat_alloc_new_dir(dir, &ts); 828 if (cluster < 0) { 829 err = cluster; 830 goto out; 831 } 832 err = vfat_add_entry(dir, &dentry->d_name, 1, cluster, &ts, &sinfo); 833 if (err) 834 goto out_free; 835 dir->i_version++; 836 inc_nlink(dir); 837 838 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); 839 brelse(sinfo.bh); 840 if (IS_ERR(inode)) { 841 err = PTR_ERR(inode); 842 /* the directory was completed, just return a error */ 843 goto out; 844 } 845 inode->i_version++; 846 inode->i_nlink = 2; 847 inode->i_mtime = inode->i_atime = inode->i_ctime = ts; 848 /* timestamp is already written, so mark_inode_dirty() is unneeded. */ 849 850 dentry->d_time = dentry->d_parent->d_inode->i_version; 851 d_instantiate(dentry, inode); 852 853 unlock_super(sb); 854 return 0; 855 856 out_free: 857 fat_free_clusters(dir, cluster); 858 out: 859 unlock_super(sb); 860 return err; 861 } 862 863 static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry, 864 struct inode *new_dir, struct dentry *new_dentry) 865 { 866 struct buffer_head *dotdot_bh; 867 struct msdos_dir_entry *dotdot_de; 868 struct inode *old_inode, *new_inode; 869 struct fat_slot_info old_sinfo, sinfo; 870 struct timespec ts; 871 loff_t dotdot_i_pos, new_i_pos; 872 int err, is_dir, update_dotdot, corrupt = 0; 873 struct super_block *sb = old_dir->i_sb; 874 875 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL; 876 old_inode = old_dentry->d_inode; 877 new_inode = new_dentry->d_inode; 878 lock_super(sb); 879 err = vfat_find(old_dir, &old_dentry->d_name, &old_sinfo); 880 if (err) 881 goto out; 882 883 is_dir = S_ISDIR(old_inode->i_mode); 884 update_dotdot = (is_dir && old_dir != new_dir); 885 if (update_dotdot) { 886 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de, 887 &dotdot_i_pos) < 0) { 888 err = -EIO; 889 goto out; 890 } 891 } 892 893 ts = CURRENT_TIME_SEC; 894 if (new_inode) { 895 if (is_dir) { 896 err = fat_dir_empty(new_inode); 897 if (err) 898 goto out; 899 } 900 new_i_pos = MSDOS_I(new_inode)->i_pos; 901 fat_detach(new_inode); 902 } else { 903 err = vfat_add_entry(new_dir, &new_dentry->d_name, is_dir, 0, 904 &ts, &sinfo); 905 if (err) 906 goto out; 907 new_i_pos = sinfo.i_pos; 908 } 909 new_dir->i_version++; 910 911 fat_detach(old_inode); 912 fat_attach(old_inode, new_i_pos); 913 if (IS_DIRSYNC(new_dir)) { 914 err = fat_sync_inode(old_inode); 915 if (err) 916 goto error_inode; 917 } else 918 mark_inode_dirty(old_inode); 919 920 if (update_dotdot) { 921 int start = MSDOS_I(new_dir)->i_logstart; 922 dotdot_de->start = cpu_to_le16(start); 923 dotdot_de->starthi = cpu_to_le16(start >> 16); 924 mark_buffer_dirty(dotdot_bh); 925 if (IS_DIRSYNC(new_dir)) { 926 err = sync_dirty_buffer(dotdot_bh); 927 if (err) 928 goto error_dotdot; 929 } 930 drop_nlink(old_dir); 931 if (!new_inode) 932 inc_nlink(new_dir); 933 } 934 935 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */ 936 old_sinfo.bh = NULL; 937 if (err) 938 goto error_dotdot; 939 old_dir->i_version++; 940 old_dir->i_ctime = old_dir->i_mtime = ts; 941 if (IS_DIRSYNC(old_dir)) 942 (void)fat_sync_inode(old_dir); 943 else 944 mark_inode_dirty(old_dir); 945 946 if (new_inode) { 947 drop_nlink(new_inode); 948 if (is_dir) 949 drop_nlink(new_inode); 950 new_inode->i_ctime = ts; 951 } 952 out: 953 brelse(sinfo.bh); 954 brelse(dotdot_bh); 955 brelse(old_sinfo.bh); 956 unlock_super(sb); 957 958 return err; 959 960 error_dotdot: 961 /* data cluster is shared, serious corruption */ 962 corrupt = 1; 963 964 if (update_dotdot) { 965 int start = MSDOS_I(old_dir)->i_logstart; 966 dotdot_de->start = cpu_to_le16(start); 967 dotdot_de->starthi = cpu_to_le16(start >> 16); 968 mark_buffer_dirty(dotdot_bh); 969 corrupt |= sync_dirty_buffer(dotdot_bh); 970 } 971 error_inode: 972 fat_detach(old_inode); 973 fat_attach(old_inode, old_sinfo.i_pos); 974 if (new_inode) { 975 fat_attach(new_inode, new_i_pos); 976 if (corrupt) 977 corrupt |= fat_sync_inode(new_inode); 978 } else { 979 /* 980 * If new entry was not sharing the data cluster, it 981 * shouldn't be serious corruption. 982 */ 983 int err2 = fat_remove_entries(new_dir, &sinfo); 984 if (corrupt) 985 corrupt |= err2; 986 sinfo.bh = NULL; 987 } 988 if (corrupt < 0) { 989 fat_fs_panic(new_dir->i_sb, 990 "%s: Filesystem corrupted (i_pos %lld)", 991 __func__, sinfo.i_pos); 992 } 993 goto out; 994 } 995 996 static const struct inode_operations vfat_dir_inode_operations = { 997 .create = vfat_create, 998 .lookup = vfat_lookup, 999 .unlink = vfat_unlink, 1000 .mkdir = vfat_mkdir, 1001 .rmdir = vfat_rmdir, 1002 .rename = vfat_rename, 1003 .setattr = fat_setattr, 1004 .getattr = fat_getattr, 1005 }; 1006 1007 static int vfat_fill_super(struct super_block *sb, void *data, int silent) 1008 { 1009 int res; 1010 1011 res = fat_fill_super(sb, data, silent, &vfat_dir_inode_operations, 1); 1012 if (res) 1013 return res; 1014 1015 if (MSDOS_SB(sb)->options.name_check != 's') 1016 sb->s_root->d_op = &vfat_dentry_ops[0]; 1017 else 1018 sb->s_root->d_op = &vfat_dentry_ops[2]; 1019 1020 return 0; 1021 } 1022 1023 static int vfat_get_sb(struct file_system_type *fs_type, 1024 int flags, const char *dev_name, 1025 void *data, struct vfsmount *mnt) 1026 { 1027 return get_sb_bdev(fs_type, flags, dev_name, data, vfat_fill_super, 1028 mnt); 1029 } 1030 1031 static struct file_system_type vfat_fs_type = { 1032 .owner = THIS_MODULE, 1033 .name = "vfat", 1034 .get_sb = vfat_get_sb, 1035 .kill_sb = kill_block_super, 1036 .fs_flags = FS_REQUIRES_DEV, 1037 }; 1038 1039 static int __init init_vfat_fs(void) 1040 { 1041 return register_filesystem(&vfat_fs_type); 1042 } 1043 1044 static void __exit exit_vfat_fs(void) 1045 { 1046 unregister_filesystem(&vfat_fs_type); 1047 } 1048 1049 MODULE_LICENSE("GPL"); 1050 MODULE_DESCRIPTION("VFAT filesystem support"); 1051 MODULE_AUTHOR("Gordon Chaffee"); 1052 1053 module_init(init_vfat_fs) 1054 module_exit(exit_vfat_fs) 1055