1/* 2 * Copyright 2017, NICTA 3 * 4 * This software may be distributed and modified according to the terms of 5 * the GNU General Public License version 2. Note that NO WARRANTY is provided. 6 * See "LICENSE_GPLv2.txt" for details. 7 * 8 * @TAG(NICTA_GPL) 9 */ 10 11/* 12 * Based on linux/fs/vfat/namei.c 13 * 14 * Written 1992,1993 by Werner Almesberger 15 * 16 * Windows95/Windows NT compatible extended MSDOS filesystem 17 * by Gordon Chaffee Copyright (C) 1995. Send bug reports for the 18 * VFAT filesystem to <chaffee@cs.berkeley.edu>. Specify 19 * what file operation caused you trouble and if you can duplicate 20 * the problem, send a script that demonstrates it. 21 * 22 * Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de> 23 * 24 * Support Multibyte characters and cleanup by 25 * OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> 26 */ 27 28 29#include <plat/linux/wrapper_pp_inferred.c> 30 31/*==========================** 32 Copied from kernel source 33**==========================*/ 34 35#include <linux/module.h> 36#include <linux/ctype.h> 37#include <linux/slab.h> 38#include <linux/namei.h> 39#include "fat.h" 40 41/* 42 * If new entry was created in the parent, it could create the 8.3 43 * alias (the shortname of logname). So, the parent may have the 44 * negative-dentry which matches the created 8.3 alias. 45 * 46 * If it happened, the negative dentry isn't actually negative 47 * anymore. So, drop it. 48 */ 49static int vfat_revalidate_shortname(struct dentry *dentry) 50{ 51 int ret = 1; 52 spin_lock(&dentry->d_lock); 53 if (dentry->d_time != d_inode(dentry->d_parent)->i_version) 54 ret = 0; 55 spin_unlock(&dentry->d_lock); 56 return ret; 57} 58 59static int vfat_revalidate(struct dentry *dentry, unsigned int flags) 60{ 61 if (flags & LOOKUP_RCU) 62 return -ECHILD; 63 64 /* This is not negative dentry. Always valid. */ 65 if (d_really_is_positive(dentry)) 66 return 1; 67 return vfat_revalidate_shortname(dentry); 68} 69 70static int vfat_revalidate_ci(struct dentry *dentry, unsigned int flags) 71{ 72 if (flags & LOOKUP_RCU) 73 return -ECHILD; 74 75 /* 76 * This is not negative dentry. Always valid. 77 * 78 * Note, rename() to existing directory entry will have ->d_inode, 79 * and will use existing name which isn't specified name by user. 80 * 81 * We may be able to drop this positive dentry here. But dropping 82 * positive dentry isn't good idea. So it's unsupported like 83 * rename("filename", "FILENAME") for now. 84 */ 85 if (d_really_is_positive(dentry)) 86 return 1; 87 88 /* 89 * This may be nfsd (or something), anyway, we can't see the 90 * intent of this. So, since this can be for creation, drop it. 91 */ 92 if (!flags) 93 return 0; 94 95 /* 96 * Drop the negative dentry, in order to make sure to use the 97 * case sensitive name which is specified by user if this is 98 * for creation. 99 */ 100 if (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET)) 101 return 0; 102 103 return vfat_revalidate_shortname(dentry); 104} 105 106/* returns the length of a struct qstr, ignoring trailing dots */ 107static unsigned int __vfat_striptail_len(unsigned int len, const char *name) 108{ 109 while (len && name[len - 1] == '.') 110 len--; 111 return len; 112} 113 114unsigned int vfat_striptail_len(const struct qstr *qstr) 115{ 116 return __vfat_striptail_len(qstr->len, qstr->name); 117} 118 119/* 120 * Compute the hash for the vfat name corresponding to the dentry. 121 * Note: if the name is invalid, we leave the hash code unchanged so 122 * that the existing dentry can be used. The vfat fs routines will 123 * return ENOENT or EINVAL as appropriate. 124 */ 125static int vfat_hash(const struct dentry *dentry, struct qstr *qstr) 126{ 127#if LINUX_VERSION_CODE < KERNEL_VERSION(4,4,0) 128 qstr->hash = full_name_hash(qstr->name, vfat_striptail_len(qstr)); 129#else 130 qstr->hash = full_name_hash(dentry, qstr->name, vfat_striptail_len(qstr)); 131#endif 132 return 0; 133} 134 135/* 136 * Compute the hash for the vfat name corresponding to the dentry. 137 * Note: if the name is invalid, we leave the hash code unchanged so 138 * that the existing dentry can be used. The vfat fs routines will 139 * return ENOENT or EINVAL as appropriate. 140 */ 141static int vfat_hashi(const struct dentry *dentry, struct qstr *qstr) 142{ 143 struct nls_table *t = MSDOS_SB(dentry->d_sb)->nls_io; 144 const unsigned char *name; 145 unsigned int len; 146 unsigned long hash; 147 148 name = qstr->name; 149 len = vfat_striptail_len(qstr); 150 151#if LINUX_VERSION_CODE < KERNEL_VERSION(4,4,0) 152 hash = init_name_hash(); 153#else 154 hash = init_name_hash(dentry); 155#endif 156 while (len--) 157 hash = partial_name_hash(nls_tolower(t, *name++), hash); 158 qstr->hash = end_name_hash(hash); 159 160 return 0; 161} 162 163/* 164 * Case insensitive compare of two vfat names. 165 */ 166#if LINUX_VERSION_CODE < KERNEL_VERSION(4,4,0) 167static int vfat_cmpi(const struct dentry *parent, const struct dentry *dentry, 168 unsigned int len, const char *str, const struct qstr *name) 169#else 170static int vfat_cmpi(const struct dentry *dentry, unsigned int len, 171 const char *str, const struct qstr *name) 172 173#endif 174{ 175#if LINUX_VERSION_CODE < KERNEL_VERSION(4,4,0) 176 struct nls_table *t = MSDOS_SB(parent->d_sb)->nls_io; 177#else 178 struct nls_table *t = MSDOS_SB(dentry->d_sb)->nls_io; 179#endif 180 unsigned int alen, blen; 181 182 /* A filename cannot end in '.' or we treat it like it has none */ 183 alen = vfat_striptail_len(name); 184 blen = __vfat_striptail_len(len, str); 185 if (alen == blen) { 186 if (nls_strnicmp(t, name->name, str, alen) == 0) 187 return 0; 188 } 189 return 1; 190} 191 192/* 193 * Case sensitive compare of two vfat names. 194 */ 195#if LINUX_VERSION_CODE < KERNEL_VERSION(4,4,0) 196static int vfat_cmp(const struct dentry *parent, const struct dentry *dentry, 197 unsigned int len, const char *str, const struct qstr *name) 198#else 199static int vfat_cmp(const struct dentry *dentry, unsigned int len, 200 const char *str, const struct qstr *name) 201#endif 202{ 203 unsigned int alen, blen; 204 205 /* A filename cannot end in '.' or we treat it like it has none */ 206 alen = vfat_striptail_len(name); 207 blen = __vfat_striptail_len(len, str); 208 if (alen == blen) { 209 if (strncmp(name->name, str, alen) == 0) 210 return 0; 211 } 212 return 1; 213} 214 215static const struct dentry_operations vfat_ci_dentry_ops = { 216 .d_revalidate = vfat_revalidate_ci, 217 .d_hash = vfat_hashi, 218 .d_compare = vfat_cmpi, 219}; 220 221static const struct dentry_operations vfat_dentry_ops = { 222 .d_revalidate = vfat_revalidate, 223 .d_hash = vfat_hash, 224 .d_compare = vfat_cmp, 225}; 226 227/* Characters that are undesirable in an MS-DOS file name */ 228 229static inline wchar_t vfat_bad_char(wchar_t w) 230{ 231 return (w < 0x0020) 232 || (w == '*') || (w == '?') || (w == '<') || (w == '>') 233 || (w == '|') || (w == '"') || (w == ':') || (w == '/') 234 || (w == '\\'); 235} 236 237static inline wchar_t vfat_replace_char(wchar_t w) 238{ 239 return (w == '[') || (w == ']') || (w == ';') || (w == ',') 240 || (w == '+') || (w == '='); 241} 242 243static wchar_t vfat_skip_char(wchar_t w) 244{ 245 return (w == '.') || (w == ' '); 246} 247 248static inline int vfat_is_used_badchars(const wchar_t *s, int len) 249{ 250 int i; 251 252 for (i = 0; i < len; i++) 253 if (vfat_bad_char(s[i])) 254 return -EINVAL; 255 256 if (s[i - 1] == ' ') /* last character cannot be space */ 257 return -EINVAL; 258 259 return 0; 260} 261 262static int vfat_find_form(struct inode *dir, unsigned char *name) 263{ 264 struct fat_slot_info sinfo; 265 int err = fat_scan(dir, name, &sinfo); 266 if (err) 267 return -ENOENT; 268 brelse(sinfo.bh); 269 return 0; 270} 271 272/* 273 * 1) Valid characters for the 8.3 format alias are any combination of 274 * letters, uppercase alphabets, digits, any of the 275 * following special characters: 276 * $ % ' ` - @ { } ~ ! # ( ) & _ ^ 277 * In this case Longfilename is not stored in disk. 278 * 279 * WinNT's Extension: 280 * File name and extension name is contain uppercase/lowercase 281 * only. And it is expressed by CASE_LOWER_BASE and CASE_LOWER_EXT. 282 * 283 * 2) File name is 8.3 format, but it contain the uppercase and 284 * lowercase char, muliti bytes char, etc. In this case numtail is not 285 * added, but Longfilename is stored. 286 * 287 * 3) When the one except for the above, or the following special 288 * character are contained: 289 * . [ ] ; , + = 290 * numtail is added, and Longfilename must be stored in disk . 291 */ 292struct shortname_info { 293 unsigned char lower:1, 294 upper:1, 295 valid:1; 296}; 297#define INIT_SHORTNAME_INFO(x) do { \ 298 (x)->lower = 1; \ 299 (x)->upper = 1; \ 300 (x)->valid = 1; \ 301} while (0) 302 303static inline int to_shortname_char(struct nls_table *nls, 304 unsigned char *buf, int buf_size, 305 wchar_t *src, struct shortname_info *info) 306{ 307 int len; 308 309 if (vfat_skip_char(*src)) { 310 info->valid = 0; 311 return 0; 312 } 313 if (vfat_replace_char(*src)) { 314 info->valid = 0; 315 buf[0] = '_'; 316 return 1; 317 } 318 319 len = nls->uni2char(*src, buf, buf_size); 320 if (len <= 0) { 321 info->valid = 0; 322 buf[0] = '_'; 323 len = 1; 324 } else if (len == 1) { 325 unsigned char prev = buf[0]; 326 327 if (buf[0] >= 0x7F) { 328 info->lower = 0; 329 info->upper = 0; 330 } 331 332 buf[0] = nls_toupper(nls, buf[0]); 333 if (isalpha(buf[0])) { 334 if (buf[0] == prev) 335 info->lower = 0; 336 else 337 info->upper = 0; 338 } 339 } else { 340 info->lower = 0; 341 info->upper = 0; 342 } 343 344 return len; 345} 346 347/* 348 * Given a valid longname, create a unique shortname. Make sure the 349 * shortname does not exist 350 * Returns negative number on error, 0 for a normal 351 * return, and 1 for valid shortname 352 */ 353static int vfat_create_shortname(struct inode *dir, struct nls_table *nls, 354 wchar_t *uname, int ulen, 355 unsigned char *name_res, unsigned char *lcase) 356{ 357 struct fat_mount_options *opts = &MSDOS_SB(dir->i_sb)->options; 358 wchar_t *ip, *ext_start, *end, *name_start; 359 unsigned char base[9], ext[4], buf[5], *p; 360 unsigned char charbuf[NLS_MAX_CHARSET_SIZE]; 361 int chl, chi; 362 int sz = 0, extlen, baselen, i, numtail_baselen, numtail2_baselen; 363 int is_shortname; 364 struct shortname_info base_info, ext_info; 365 366 is_shortname = 1; 367 INIT_SHORTNAME_INFO(&base_info); 368 INIT_SHORTNAME_INFO(&ext_info); 369 370 /* Now, we need to create a shortname from the long name */ 371 ext_start = end = &uname[ulen]; 372 while (--ext_start >= uname) { 373 if (*ext_start == 0x002E) { /* is `.' */ 374 if (ext_start == end - 1) { 375 sz = ulen; 376 ext_start = NULL; 377 } 378 break; 379 } 380 } 381 382 if (ext_start == uname - 1) { 383 sz = ulen; 384 ext_start = NULL; 385 } else if (ext_start) { 386 /* 387 * Names which start with a dot could be just 388 * an extension eg. "...test". In this case Win95 389 * uses the extension as the name and sets no extension. 390 */ 391 name_start = &uname[0]; 392 while (name_start < ext_start) { 393 if (!vfat_skip_char(*name_start)) 394 break; 395 name_start++; 396 } 397 if (name_start != ext_start) { 398 sz = ext_start - uname; 399 ext_start++; 400 } else { 401 sz = ulen; 402 ext_start = NULL; 403 } 404 } 405 406 numtail_baselen = 6; 407 numtail2_baselen = 2; 408 for (baselen = i = 0, p = base, ip = uname; i < sz; i++, ip++) { 409 chl = to_shortname_char(nls, charbuf, sizeof(charbuf), 410 ip, &base_info); 411 if (chl == 0) 412 continue; 413 414 if (baselen < 2 && (baselen + chl) > 2) 415 numtail2_baselen = baselen; 416 if (baselen < 6 && (baselen + chl) > 6) 417 numtail_baselen = baselen; 418 for (chi = 0; chi < chl; chi++) { 419 *p++ = charbuf[chi]; 420 baselen++; 421 if (baselen >= 8) 422 break; 423 } 424 if (baselen >= 8) { 425 if ((chi < chl - 1) || (ip + 1) - uname < sz) 426 is_shortname = 0; 427 break; 428 } 429 } 430 if (baselen == 0) { 431 return -EINVAL; 432 } 433 434 extlen = 0; 435 if (ext_start) { 436 for (p = ext, ip = ext_start; extlen < 3 && ip < end; ip++) { 437 chl = to_shortname_char(nls, charbuf, sizeof(charbuf), 438 ip, &ext_info); 439 if (chl == 0) 440 continue; 441 442 if ((extlen + chl) > 3) { 443 is_shortname = 0; 444 break; 445 } 446 for (chi = 0; chi < chl; chi++) { 447 *p++ = charbuf[chi]; 448 extlen++; 449 } 450 if (extlen >= 3) { 451 if (ip + 1 != end) 452 is_shortname = 0; 453 break; 454 } 455 } 456 } 457 ext[extlen] = '\0'; 458 base[baselen] = '\0'; 459 460 /* Yes, it can happen. ".\xe5" would do it. */ 461 if (base[0] == DELETED_FLAG) 462 base[0] = 0x05; 463 464 /* OK, at this point we know that base is not longer than 8 symbols, 465 * ext is not longer than 3, base is nonempty, both don't contain 466 * any bad symbols (lowercase transformed to uppercase). 467 */ 468 469 memset(name_res, ' ', MSDOS_NAME); 470 memcpy(name_res, base, baselen); 471 memcpy(name_res + 8, ext, extlen); 472 *lcase = 0; 473 if (is_shortname && base_info.valid && ext_info.valid) { 474 if (vfat_find_form(dir, name_res) == 0) 475 return -EEXIST; 476 477 if (opts->shortname & VFAT_SFN_CREATE_WIN95) { 478 return (base_info.upper && ext_info.upper); 479 } else if (opts->shortname & VFAT_SFN_CREATE_WINNT) { 480 if ((base_info.upper || base_info.lower) && 481 (ext_info.upper || ext_info.lower)) { 482 if (!base_info.upper && base_info.lower) 483 *lcase |= CASE_LOWER_BASE; 484 if (!ext_info.upper && ext_info.lower) 485 *lcase |= CASE_LOWER_EXT; 486 return 1; 487 } 488 return 0; 489 } else { 490 BUG(); 491 } 492 } 493 494 if (opts->numtail == 0) 495 if (vfat_find_form(dir, name_res) < 0) 496 return 0; 497 498 /* 499 * Try to find a unique extension. This used to 500 * iterate through all possibilities sequentially, 501 * but that gave extremely bad performance. Windows 502 * only tries a few cases before using random 503 * values for part of the base. 504 */ 505 506 if (baselen > 6) { 507 baselen = numtail_baselen; 508 name_res[7] = ' '; 509 } 510 name_res[baselen] = '~'; 511 for (i = 1; i < 10; i++) { 512 name_res[baselen + 1] = i + '0'; 513 if (vfat_find_form(dir, name_res) < 0) 514 return 0; 515 } 516 517 i = jiffies; 518 sz = (jiffies >> 16) & 0x7; 519 if (baselen > 2) { 520 baselen = numtail2_baselen; 521 name_res[7] = ' '; 522 } 523 name_res[baselen + 4] = '~'; 524 name_res[baselen + 5] = '1' + sz; 525 while (1) { 526 snprintf(buf, sizeof(buf), "%04X", i & 0xffff); 527 memcpy(&name_res[baselen], buf, 4); 528 if (vfat_find_form(dir, name_res) < 0) 529 break; 530 i -= 11; 531 } 532 return 0; 533} 534 535/* Translate a string, including coded sequences into Unicode */ 536static int 537xlate_to_uni(const unsigned char *name, int len, unsigned char *outname, 538 int *longlen, int *outlen, int escape, int utf8, 539 struct nls_table *nls) 540{ 541 const unsigned char *ip; 542 unsigned char nc; 543 unsigned char *op; 544 unsigned int ec; 545 int i, k, fill; 546 int charlen; 547 548 if (utf8) { 549 *outlen = utf8s_to_utf16s(name, len, UTF16_HOST_ENDIAN, 550 (wchar_t *) outname, FAT_LFN_LEN + 2); 551 if (*outlen < 0) 552 return *outlen; 553 else if (*outlen > FAT_LFN_LEN) 554 return -ENAMETOOLONG; 555 556 op = &outname[*outlen * sizeof(wchar_t)]; 557 } else { 558 for (i = 0, ip = name, op = outname, *outlen = 0; 559 i < len && *outlen < FAT_LFN_LEN; 560 *outlen += 1) { 561 if (escape && (*ip == ':')) { 562 if (i > len - 5) 563 return -EINVAL; 564 ec = 0; 565 for (k = 1; k < 5; k++) { 566 nc = ip[k]; 567 ec <<= 4; 568 if (nc >= '0' && nc <= '9') { 569 ec |= nc - '0'; 570 continue; 571 } 572 if (nc >= 'a' && nc <= 'f') { 573 ec |= nc - ('a' - 10); 574 continue; 575 } 576 if (nc >= 'A' && nc <= 'F') { 577 ec |= nc - ('A' - 10); 578 continue; 579 } 580 return -EINVAL; 581 } 582 *op++ = ec & 0xFF; 583 *op++ = ec >> 8; 584 ip += 5; 585 i += 5; 586 } else { 587 charlen = nls->char2uni(ip, len - i, 588 (wchar_t *)op); 589 if (charlen < 0) 590 return -EINVAL; 591 ip += charlen; 592 i += charlen; 593 op += 2; 594 } 595 } 596 if (i < len) 597 return -ENAMETOOLONG; 598 } 599 600 *longlen = *outlen; 601 if (*outlen % 13) { 602 *op++ = 0; 603 *op++ = 0; 604 *outlen += 1; 605 if (*outlen % 13) { 606 fill = 13 - (*outlen % 13); 607 for (i = 0; i < fill; i++) { 608 *op++ = 0xff; 609 *op++ = 0xff; 610 } 611 *outlen += fill; 612 } 613 } 614 615 return 0; 616} 617 618int vfat_build_slots(struct inode *dir, const unsigned char *name, 619 int len, int is_dir, int cluster, 620 struct timespec *ts, 621 struct msdos_dir_slot *slots, int *nr_slots) 622{ 623 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb); 624 struct fat_mount_options *opts = &sbi->options; 625 struct msdos_dir_slot *ps; 626 struct msdos_dir_entry *de; 627 unsigned char cksum, lcase; 628 unsigned char msdos_name[MSDOS_NAME]; 629 wchar_t *uname; 630 __le16 time, date; 631 u8 time_cs; 632 int err, ulen, usize, i; 633 loff_t offset; 634 635 *nr_slots = 0; 636 637 uname = __getname(); 638 if (!uname) 639 return -ENOMEM; 640 641 err = xlate_to_uni(name, len, (unsigned char *)uname, &ulen, &usize, 642 opts->unicode_xlate, opts->utf8, sbi->nls_io); 643 if (err) 644 goto out_free; 645 646 err = vfat_is_used_badchars(uname, ulen); 647 if (err) 648 goto out_free; 649 650 err = vfat_create_shortname(dir, sbi->nls_disk, uname, ulen, 651 msdos_name, &lcase); 652 if (err < 0) 653 goto out_free; 654 else if (err == 1) { 655 de = (struct msdos_dir_entry *)slots; 656 err = 0; 657 goto shortname; 658 } 659 660 /* build the entry of long file name */ 661 cksum = fat_checksum(msdos_name); 662 663 *nr_slots = usize / 13; 664 for (ps = slots, i = *nr_slots; i > 0; i--, ps++) { 665 ps->id = i; 666 ps->attr = ATTR_EXT; 667 ps->reserved = 0; 668 ps->alias_checksum = cksum; 669 ps->start = 0; 670 offset = (i - 1) * 13; 671 fatwchar_to16(ps->name0_4, uname + offset, 5); 672 fatwchar_to16(ps->name5_10, uname + offset + 5, 6); 673 fatwchar_to16(ps->name11_12, uname + offset + 11, 2); 674 } 675 slots[0].id |= 0x40; 676 de = (struct msdos_dir_entry *)ps; 677 678shortname: 679 /* build the entry of 8.3 alias name */ 680 (*nr_slots)++; 681 memcpy(de->name, msdos_name, MSDOS_NAME); 682 de->attr = is_dir ? ATTR_DIR : ATTR_ARCH; 683 de->lcase = lcase; 684 fat_time_unix2fat(sbi, ts, &time, &date, &time_cs); 685 de->time = de->ctime = time; 686 de->date = de->cdate = de->adate = date; 687 de->ctime_cs = time_cs; 688 fat_set_start(de, cluster); 689 de->size = 0; 690out_free: 691 __putname(uname); 692 return err; 693} 694 695int vfat_find(struct inode *dir, struct qstr *qname, 696 struct fat_slot_info *sinfo) 697{ 698 unsigned int len = vfat_striptail_len(qname); 699 if (len == 0) 700 return -ENOENT; 701 return fat_search_long(dir, qname->name, len, sinfo); 702} 703 704// CHECK: static issue? 705 706int vfat_add_entry(struct inode *dir, struct qstr *qname, int is_dir, 707 int cluster, struct timespec *ts, 708 struct fat_slot_info *sinfo) 709{ 710 struct msdos_dir_slot *slots; 711 unsigned int len; 712 int err, nr_slots; 713 714 len = vfat_striptail_len(qname); 715 if (len == 0) 716 return -ENOENT; // why is this negative 717 718 slots = kmalloc(sizeof(*slots) * MSDOS_SLOTS, GFP_NOFS); 719 if (slots == NULL) 720 return -ENOMEM; 721 722 err = vfat_build_slots(dir, qname->name, len, is_dir, cluster, ts, 723 slots, &nr_slots); 724 if (err){ 725 kfree(slots); 726 return err; 727 } 728 729 // what's the point of slots? (check) 730 err = fat_add_entries(dir, slots, nr_slots, sinfo); 731 if (err){ 732 kfree(slots); 733 return err; 734 } 735 /* update timestamp */ 736 dir->i_ctime = dir->i_mtime = dir->i_atime = *ts; 737 if (IS_DIRSYNC(dir)) 738 (void)fat_sync_inode(dir); 739 else{ 740 mark_inode_dirty(dir); // old error came from here [segfault] 741 } 742 kfree(slots); 743 return err; 744} 745 746#if LINUX_VERSION_CODE < KERNEL_VERSION(4,4,0) 747static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry, 748 struct inode *new_dir, struct dentry *new_dentry) 749#else 750 static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry, 751 struct inode *new_dir, struct dentry *new_dentry, 752 unsigned int flags) 753#endif 754{ 755 struct buffer_head *dotdot_bh; 756 struct msdos_dir_entry *dotdot_de; 757 struct inode *old_inode, *new_inode; 758 struct fat_slot_info old_sinfo, sinfo; 759 struct timespec ts; 760 loff_t new_i_pos; 761 int err, is_dir, update_dotdot, corrupt = 0; 762 struct super_block *sb = old_dir->i_sb; 763 764 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL; 765 old_inode = d_inode(old_dentry); 766 new_inode = d_inode(new_dentry); 767 mutex_lock(&MSDOS_SB(sb)->s_lock); 768 err = vfat_find(old_dir, &old_dentry->d_name, &old_sinfo); 769 if (err) 770 goto out; 771 772 is_dir = S_ISDIR(old_inode->i_mode); 773 update_dotdot = (is_dir && old_dir != new_dir); 774 if (update_dotdot) { 775 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de)) { 776 err = -EIO; 777 goto out; 778 } 779 } 780 781 ts = current_time(old_inode); 782 if (new_inode) { 783 if (is_dir) { 784 err = fat_dir_empty(new_inode); 785 if (err) 786 goto out; 787 } 788 new_i_pos = MSDOS_I(new_inode)->i_pos; 789 fat_detach(new_inode); 790 } else { 791 err = vfat_add_entry(new_dir, &new_dentry->d_name, is_dir, 0, 792 &ts, &sinfo); 793 if (err) 794 goto out; 795 new_i_pos = sinfo.i_pos; 796 } 797 new_dir->i_version++; 798 799 fat_detach(old_inode); 800 fat_attach(old_inode, new_i_pos); 801 if (IS_DIRSYNC(new_dir)) { 802 err = fat_sync_inode(old_inode); 803 if (err) 804 goto error_inode; 805 } else 806 mark_inode_dirty(old_inode); 807 808 if (update_dotdot) { 809 fat_set_start(dotdot_de, MSDOS_I(new_dir)->i_logstart); 810 mark_buffer_dirty_inode(dotdot_bh, old_inode); 811 if (IS_DIRSYNC(new_dir)) { 812 err = sync_dirty_buffer(dotdot_bh); 813 if (err) 814 goto error_dotdot; 815 } 816 drop_nlink(old_dir); 817 if (!new_inode) 818 inc_nlink(new_dir); 819 } 820 821 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */ 822 old_sinfo.bh = NULL; 823 if (err) 824 goto error_dotdot; 825 old_dir->i_version++; 826 old_dir->i_ctime = old_dir->i_mtime = ts; 827 if (IS_DIRSYNC(old_dir)) 828 (void)fat_sync_inode(old_dir); 829 else 830 mark_inode_dirty(old_dir); 831 832 if (new_inode) { 833 drop_nlink(new_inode); 834 if (is_dir) 835 drop_nlink(new_inode); 836 new_inode->i_ctime = ts; 837 } 838out: 839 brelse(sinfo.bh); 840 brelse(dotdot_bh); 841 brelse(old_sinfo.bh); 842 mutex_unlock(&MSDOS_SB(sb)->s_lock); 843 844 return err; 845 846error_dotdot: 847 /* data cluster is shared, serious corruption */ 848 corrupt = 1; 849 850 if (update_dotdot) { 851 fat_set_start(dotdot_de, MSDOS_I(old_dir)->i_logstart); 852 mark_buffer_dirty_inode(dotdot_bh, old_inode); 853 corrupt |= sync_dirty_buffer(dotdot_bh); 854 } 855error_inode: 856 fat_detach(old_inode); 857 fat_attach(old_inode, old_sinfo.i_pos); 858 if (new_inode) { 859 fat_attach(new_inode, new_i_pos); 860 if (corrupt) 861 corrupt |= fat_sync_inode(new_inode); 862 } else { 863 /* 864 * If new entry was not sharing the data cluster, it 865 * shouldn't be serious corruption. 866 */ 867 int err2 = fat_remove_entries(new_dir, &sinfo); 868 if (corrupt) 869 corrupt |= err2; 870 sinfo.bh = NULL; 871 } 872 if (corrupt < 0) { 873 fat_fs_error(new_dir->i_sb, 874 "%s: Filesystem corrupted (i_pos %lld)", 875 __func__, sinfo.i_pos); 876 } 877 goto out; 878} 879 880static const struct inode_operations vfat_dir_inode_operations = { 881 .create = vfat_create_ac, 882 .lookup = vfat_lookup_ac, 883 .unlink = vfat_unlink_ac, 884 .mkdir = vfat_mkdir_ac, 885 .rmdir = vfat_rmdir_ac, 886 .rename = vfat_rename, 887 .setattr = fat_setattr, 888 .getattr = fat_getattr, 889}; 890 891static void setup(struct super_block *sb) 892{ 893 MSDOS_SB(sb)->dir_ops = &vfat_dir_inode_operations; 894 if (MSDOS_SB(sb)->options.name_check != 's') 895 sb->s_d_op = &vfat_ci_dentry_ops; 896 else 897 sb->s_d_op = &vfat_dentry_ops; 898} 899 900static int vfat_fill_super(struct super_block *sb, void *data, int silent) 901{ 902 return fat_fill_super(sb, data, silent, 1, setup); 903} 904 905/*==========================** 906 From skel-fs 907**==========================*/ 908 909static struct dentry *vfat_mount(struct file_system_type *fs_type, int flags, 910 const char *dev_name, void *data) 911{ 912 return mount_bdev(fs_type, flags, dev_name, data, vfat_fill_super); 913} 914 915static void kill_vfat_super(struct super_block *sb) 916{ 917 // implement filesystem specific super block tear-down here. 918 kill_block_super(sb); 919} 920 921static struct file_system_type vfat_fs_type = { 922 .owner = THIS_MODULE, 923 .name = "cogent-vfat", 924 .mount = vfat_mount, 925 .kill_sb = kill_vfat_super, 926 .fs_flags = FS_REQUIRES_DEV 927}; 928 929static int __init init_vfat(void) 930{ 931 int err = 0; 932 933 printk(KERN_INFO "Registering VFAT\n"); 934 935 // Implement filesystem specific init functions here. 936 err = register_filesystem(&vfat_fs_type); 937 938 return err; 939} 940 941 942static void __exit exit_vfat(void) 943{ 944 printk(KERN_INFO "Un-Registering VFAT\n"); 945 946 // Implement filesystem specific tear-down functions here. 947 unregister_filesystem(&vfat_fs_type); 948} 949 950 951module_init(init_vfat) 952module_exit(exit_vfat) 953 954MODULE_AUTHOR("Data61 TFS Team"); 955MODULE_DESCRIPTION("VFAT implementation in Cogent"); 956MODULE_LICENSE("GPL"); 957