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