fs/fat/dir.c

   1 /*
   2  *  linux/fs/fat/dir.c
   3  *
   4  *  directory handling functions for fat-based filesystems
   5  *
   6  *  Written 1992,1993 by Werner Almesberger
   7  *
   8  *  Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu>
   9  *
  10  *  VFAT extensions by Gordon Chaffee <chaffee@plateau.cs.berkeley.edu>
  11  *  Merged with msdos fs by Henrik Storner <storner@osiris.ping.dk>
  12  *  Rewritten for constant inumbers. Plugged buffer overrun in readdir(). AV
  13  *  Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de>
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/slab.h>
  18 #include <linux/time.h>
  19 #include <linux/buffer_head.h>
  20 #include <linux/compat.h>
  21 #include <asm/uaccess.h>
  22 #include <linux/kernel.h>
  23 #include "fat.h"
  24
  25 /*
  26  * Maximum buffer size of short name.
  27  * [(MSDOS_NAME + '.') * max one char + nul]
  28  * For msdos style, ['.' (hidden) + MSDOS_NAME + '.' + nul]
  29  */
  30 #define FAT_MAX_SHORT_SIZE      ((MSDOS_NAME + 1) * NLS_MAX_CHARSET_SIZE + 1)
  31 /*
  32  * Maximum buffer size of unicode chars from slots.
  33  * [(max longname slots * 13 (size in a slot) + nul) * sizeof(wchar_t)]
  34  */
  35 #define FAT_MAX_UNI_CHARS       ((MSDOS_SLOTS - 1) * 13 + 1)
  36 #define FAT_MAX_UNI_SIZE        (FAT_MAX_UNI_CHARS * sizeof(wchar_t))
  37
  38 static inline loff_t fat_make_i_pos(struct super_block *sb,
  39                                     struct buffer_head *bh,
  40                                     struct msdos_dir_entry *de)
  41 {
  42         return ((loff_t)bh->b_blocknr << MSDOS_SB(sb)->dir_per_block_bits)
  43                 | (de - (struct msdos_dir_entry *)bh->b_data);
  44 }
  45
  46 static inline void fat_dir_readahead(struct inode *dir, sector_t iblock,
  47                                      sector_t phys)
  48 {
  49         struct super_block *sb = dir->i_sb;
  50         struct msdos_sb_info *sbi = MSDOS_SB(sb);
  51         struct buffer_head *bh;
  52         int sec;
  53
  54         /* This is not a first sector of cluster, or sec_per_clus == 1 */
  55         if ((iblock & (sbi->sec_per_clus - 1)) || sbi->sec_per_clus == 1)
  56                 return;
  57         /* root dir of FAT12/FAT16 */
  58         if ((sbi->fat_bits != 32) && (dir->i_ino == MSDOS_ROOT_INO))
  59                 return;
  60
  61         bh = sb_find_get_block(sb, phys);
  62         if (bh == NULL || !buffer_uptodate(bh)) {
  63                 for (sec = 0; sec < sbi->sec_per_clus; sec++)
  64                         sb_breadahead(sb, phys + sec);
  65         }
  66         brelse(bh);
  67 }
  68
  69 /* Returns the inode number of the directory entry at offset pos. If bh is
  70    non-NULL, it is brelse'd before. Pos is incremented. The buffer header is
  71    returned in bh.
  72    AV. Most often we do it item-by-item. Makes sense to optimize.
  73    AV. OK, there we go: if both bh and de are non-NULL we assume that we just
  74    AV. want the next entry (took one explicit de=NULL in vfat/namei.c).
  75    AV. It's done in fat_get_entry() (inlined), here the slow case lives.
  76    AV. Additionally, when we return -1 (i.e. reached the end of directory)
  77    AV. we make bh NULL.
  78  */
  79 static int fat__get_entry(struct inode *dir, loff_t *pos,
  80                           struct buffer_head **bh, struct msdos_dir_entry **de)
  81 {
  82         struct super_block *sb = dir->i_sb;
  83         sector_t phys, iblock;
  84         unsigned long mapped_blocks;
  85         int err, offset;
  86
  87 next:
  88         if (*bh)
  89                 brelse(*bh);
  90
  91         *bh = NULL;
  92         iblock = *pos >> sb->s_blocksize_bits;
  93         err = fat_bmap(dir, iblock, &phys, &mapped_blocks, 0);
  94         if (err || !phys)
  95                 return -1;      /* beyond EOF or error */
  96
  97         fat_dir_readahead(dir, iblock, phys);
  98
  99         *bh = sb_bread(sb, phys);
 100         if (*bh == NULL) {
 101                 printk(KERN_ERR "FAT: Directory bread(block %llu) failed\n",
 102                        (llu)phys);
 103                 /* skip this block */
 104                 *pos = (iblock + 1) << sb->s_blocksize_bits;
 105                 goto next;
 106         }
 107
 108         offset = *pos & (sb->s_blocksize - 1);
 109         *pos += sizeof(struct msdos_dir_entry);
 110         *de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
 111
 112         return 0;
 113 }
 114
 115 static inline int fat_get_entry(struct inode *dir, loff_t *pos,
 116                                 struct buffer_head **bh,
 117                                 struct msdos_dir_entry **de)
 118 {
 119         /* Fast stuff first */
 120         if (*bh && *de &&
 121             (*de - (struct msdos_dir_entry *)(*bh)->b_data) < MSDOS_SB(dir->i_sb)->dir_per_block - 1) {
 122                 *pos += sizeof(struct msdos_dir_entry);
 123                 (*de)++;
 124                 return 0;
 125         }
 126         return fat__get_entry(dir, pos, bh, de);
 127 }
 128
 129 /*
 130  * Convert Unicode 16 to UTF-8, translated Unicode, or ASCII.
 131  * If uni_xlate is enabled and we can't get a 1:1 conversion, use a
 132  * colon as an escape character since it is normally invalid on the vfat
 133  * filesystem. The following four characters are the hexadecimal digits
 134  * of Unicode value. This lets us do a full dump and restore of Unicode
 135  * filenames. We could get into some trouble with long Unicode names,
 136  * but ignore that right now.
 137  * Ahem... Stack smashing in ring 0 isn't fun. Fixed.
 138  */
 139 static int uni16_to_x8(unsigned char *ascii, const wchar_t *uni, int len,
 140                        int uni_xlate, struct nls_table *nls)
 141 {
 142         const wchar_t *ip;
 143         wchar_t ec;
 144         unsigned char *op;
 145         int charlen;
 146
 147         ip = uni;
 148         op = ascii;
 149
 150         while (*ip && ((len - NLS_MAX_CHARSET_SIZE) > 0)) {
 151                 ec = *ip++;
 152                 if ((charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE)) > 0) {
 153                         op += charlen;
 154                         len -= charlen;
 155                 } else {
 156                         if (uni_xlate == 1) {
 157                                 *op++ = ':';
 158                                 op = pack_hex_byte(op, ec >> 8);
 159                                 op = pack_hex_byte(op, ec);
 160                                 len -= 5;
 161                         } else {
 162                                 *op++ = '?';
 163                                 len--;
 164                         }
 165                 }
 166         }
 167
 168         if (unlikely(*ip)) {
 169                 printk(KERN_WARNING "FAT: filename was truncated while "
 170                        "converting.");
 171         }
 172
 173         *op = 0;
 174         return (op - ascii);
 175 }
 176
 177 static inline int fat_uni_to_x8(struct msdos_sb_info *sbi, const wchar_t *uni,
 178                                 unsigned char *buf, int size)
 179 {
 180         if (sbi->options.utf8)
 181                 return utf16s_to_utf8s(uni, FAT_MAX_UNI_CHARS,
 182                                 UTF16_HOST_ENDIAN, buf, size);
 183         else
 184                 return uni16_to_x8(buf, uni, size, sbi->options.unicode_xlate,
 185                                    sbi->nls_io);
 186 }
 187
 188 static inline int
 189 fat_short2uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
 190 {
 191         int charlen;
 192
 193         charlen = t->char2uni(c, clen, uni);
 194         if (charlen < 0) {
 195                 *uni = 0x003f;  /* a question mark */
 196                 charlen = 1;
 197         }
 198         return charlen;
 199 }
 200
 201 static inline int
 202 fat_short2lower_uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
 203 {
 204         int charlen;
 205         wchar_t wc;
 206
 207         charlen = t->char2uni(c, clen, &wc);
 208         if (charlen < 0) {
 209                 *uni = 0x003f;  /* a question mark */
 210                 charlen = 1;
 211         } else if (charlen <= 1) {
 212                 unsigned char nc = t->charset2lower[*c];
 213
 214                 if (!nc)
 215                         nc = *c;
 216
 217                 if ( (charlen = t->char2uni(&nc, 1, uni)) < 0) {
 218                         *uni = 0x003f;  /* a question mark */
 219                         charlen = 1;
 220                 }
 221         } else
 222                 *uni = wc;
 223
 224         return charlen;
 225 }
 226
 227 static inline int
 228 fat_shortname2uni(struct nls_table *nls, unsigned char *buf, int buf_size,
 229                   wchar_t *uni_buf, unsigned short opt, int lower)
 230 {
 231         int len = 0;
 232
 233         if (opt & VFAT_SFN_DISPLAY_LOWER)
 234                 len =  fat_short2lower_uni(nls, buf, buf_size, uni_buf);
 235         else if (opt & VFAT_SFN_DISPLAY_WIN95)
 236                 len = fat_short2uni(nls, buf, buf_size, uni_buf);
 237         else if (opt & VFAT_SFN_DISPLAY_WINNT) {
 238                 if (lower)
 239                         len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);
 240                 else
 241                         len = fat_short2uni(nls, buf, buf_size, uni_buf);
 242         } else
 243                 len = fat_short2uni(nls, buf, buf_size, uni_buf);
 244
 245         return len;
 246 }
 247
 248 static inline int fat_name_match(struct msdos_sb_info *sbi,
 249                                  const unsigned char *a, int a_len,
 250                                  const unsigned char *b, int b_len)
 251 {
 252         if (a_len != b_len)
 253                 return 0;
 254
 255         if (sbi->options.name_check != 's')
 256                 return !nls_strnicmp(sbi->nls_io, a, b, a_len);
 257         else
 258                 return !memcmp(a, b, a_len);
 259 }
 260
 261 enum { PARSE_INVALID = 1, PARSE_NOT_LONGNAME, PARSE_EOF, };
 262
 263 /**
 264  * fat_parse_long - Parse extended directory entry.
 265  *
 266  * This function returns zero on success, negative value on error, or one of
 267  * the following:
 268  *
 269  * %PARSE_INVALID - Directory entry is invalid.
 270  * %PARSE_NOT_LONGNAME - Directory entry does not contain longname.
 271  * %PARSE_EOF - Directory has no more entries.
 272  */
 273 static int fat_parse_long(struct inode *dir, loff_t *pos,
 274                           struct buffer_head **bh, struct msdos_dir_entry **de,
 275                           wchar_t **unicode, unsigned char *nr_slots)
 276 {
 277         struct msdos_dir_slot *ds;
 278         unsigned char id, slot, slots, alias_checksum;
 279
 280         if (!*unicode) {
 281                 *unicode = __getname();
 282                 if (!*unicode) {
 283                         brelse(*bh);
 284                         return -ENOMEM;
 285                 }
 286         }
 287 parse_long:
 288         slots = 0;
 289         ds = (struct msdos_dir_slot *)*de;
 290         id = ds->id;
 291         if (!(id & 0x40))
 292                 return PARSE_INVALID;
 293         slots = id & ~0x40;
 294         if (slots > 20 || !slots)       /* ceil(256 * 2 / 26) */
 295                 return PARSE_INVALID;
 296         *nr_slots = slots;
 297         alias_checksum = ds->alias_checksum;
 298
 299         slot = slots;
 300         while (1) {
 301                 int offset;
 302
 303                 slot--;
 304                 offset = slot * 13;
 305                 fat16_towchar(*unicode + offset, ds->name0_4, 5);
 306                 fat16_towchar(*unicode + offset + 5, ds->name5_10, 6);
 307                 fat16_towchar(*unicode + offset + 11, ds->name11_12, 2);
 308
 309                 if (ds->id & 0x40)
 310                         (*unicode)[offset + 13] = 0;
 311                 if (fat_get_entry(dir, pos, bh, de) < 0)
 312                         return PARSE_EOF;
 313                 if (slot == 0)
 314                         break;
 315                 ds = (struct msdos_dir_slot *)*de;
 316                 if (ds->attr != ATTR_EXT)
 317                         return PARSE_NOT_LONGNAME;
 318                 if ((ds->id & ~0x40) != slot)
 319                         goto parse_long;
 320                 if (ds->alias_checksum != alias_checksum)
 321                         goto parse_long;
 322         }
 323         if ((*de)->name[0] == DELETED_FLAG)
 324                 return PARSE_INVALID;
 325         if ((*de)->attr == ATTR_EXT)
 326                 goto parse_long;
 327         if (IS_FREE((*de)->name) || ((*de)->attr & ATTR_VOLUME))
 328                 return PARSE_INVALID;
 329         if (fat_checksum((*de)->name) != alias_checksum)
 330                 *nr_slots = 0;
 331
 332         return 0;
 333 }
 334
 335 /*
 336  * Return values: negative -> error, 0 -> not found, positive -> found,
 337  * value is the total amount of slots, including the shortname entry.
 338  */
 339 int fat_search_long(struct inode *inode, const unsigned char *name,
 340                     int name_len, struct fat_slot_info *sinfo)
 341 {
 342         struct super_block *sb = inode->i_sb;
 343         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 344         struct buffer_head *bh = NULL;
 345         struct msdos_dir_entry *de;
 346         struct nls_table *nls_disk = sbi->nls_disk;
 347         unsigned char nr_slots;
 348         wchar_t bufuname[14];
 349         wchar_t *unicode = NULL;
 350         unsigned char work[MSDOS_NAME];
 351         unsigned char bufname[FAT_MAX_SHORT_SIZE];
 352         unsigned short opt_shortname = sbi->options.shortname;
 353         loff_t cpos = 0;
 354         int chl, i, j, last_u, err, len;
 355
 356         err = -ENOENT;
 357         while (1) {
 358                 if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
 359                         goto end_of_dir;
 360 parse_record:
 361                 nr_slots = 0;
 362                 if (de->name[0] == DELETED_FLAG)
 363                         continue;
 364                 if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
 365                         continue;
 366                 if (de->attr != ATTR_EXT && IS_FREE(de->name))
 367                         continue;
 368                 if (de->attr == ATTR_EXT) {
 369                         int status = fat_parse_long(inode, &cpos, &bh, &de,
 370                                                     &unicode, &nr_slots);
 371                         if (status < 0) {
 372                                 err = status;
 373                                 goto end_of_dir;
 374                         } else if (status == PARSE_INVALID)
 375                                 continue;
 376                         else if (status == PARSE_NOT_LONGNAME)
 377                                 goto parse_record;
 378                         else if (status == PARSE_EOF)
 379                                 goto end_of_dir;
 380                 }
 381
 382                 memcpy(work, de->name, sizeof(de->name));
 383                 /* see namei.c, msdos_format_name */
 384                 if (work[0] == 0x05)
 385                         work[0] = 0xE5;
 386                 for (i = 0, j = 0, last_u = 0; i < 8;) {
 387                         if (!work[i])
 388                                 break;
 389                         chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
 390                                                 &bufuname[j++], opt_shortname,
 391                                                 de->lcase & CASE_LOWER_BASE);
 392                         if (chl <= 1) {
 393                                 if (work[i] != ' ')
 394                                         last_u = j;
 395                         } else {
 396                                 last_u = j;
 397                         }
 398                         i += chl;
 399                 }
 400                 j = last_u;
 401                 fat_short2uni(nls_disk, ".", 1, &bufuname[j++]);
 402                 for (i = 8; i < MSDOS_NAME;) {
 403                         if (!work[i])
 404                                 break;
 405                         chl = fat_shortname2uni(nls_disk, &work[i],
 406                                                 MSDOS_NAME - i,
 407                                                 &bufuname[j++], opt_shortname,
 408                                                 de->lcase & CASE_LOWER_EXT);
 409                         if (chl <= 1) {
 410                                 if (work[i] != ' ')
 411                                         last_u = j;
 412                         } else {
 413                                 last_u = j;
 414                         }
 415                         i += chl;
 416                 }
 417                 if (!last_u)
 418                         continue;
 419
 420                 /* Compare shortname */
 421                 bufuname[last_u] = 0x0000;
 422                 len = fat_uni_to_x8(sbi, bufuname, bufname, sizeof(bufname));
 423                 if (fat_name_match(sbi, name, name_len, bufname, len))
 424                         goto found;
 425
 426                 if (nr_slots) {
 427                         void *longname = unicode + FAT_MAX_UNI_CHARS;
 428                         int size = PATH_MAX - FAT_MAX_UNI_SIZE;
 429
 430                         /* Compare longname */
 431                         len = fat_uni_to_x8(sbi, unicode, longname, size);
 432                         if (fat_name_match(sbi, name, name_len, longname, len))
 433                                 goto found;
 434                 }
 435         }
 436
 437 found:
 438         nr_slots++;     /* include the de */
 439         sinfo->slot_off = cpos - nr_slots * sizeof(*de);
 440         sinfo->nr_slots = nr_slots;
 441         sinfo->de = de;
 442         sinfo->bh = bh;
 443         sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
 444         err = 0;
 445 end_of_dir:
 446         if (unicode)
 447                 __putname(unicode);
 448
 449         return err;
 450 }
 451
 452 EXPORT_SYMBOL_GPL(fat_search_long);
 453
 454 struct fat_ioctl_filldir_callback {
 455         void __user *dirent;
 456         int result;
 457         /* for dir ioctl */
 458         const char *longname;
 459         int long_len;
 460         const char *shortname;
 461         int short_len;
 462 };
 463
 464 static int __fat_readdir(struct inode *inode, struct file *filp, void *dirent,
 465                          filldir_t filldir, int short_only, int both)
 466 {
 467         struct super_block *sb = inode->i_sb;
 468         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 469         struct buffer_head *bh;
 470         struct msdos_dir_entry *de;
 471         struct nls_table *nls_disk = sbi->nls_disk;
 472         unsigned char nr_slots;
 473         wchar_t bufuname[14];
 474         wchar_t *unicode = NULL;
 475         unsigned char c, work[MSDOS_NAME];
 476         unsigned char bufname[FAT_MAX_SHORT_SIZE], *ptname = bufname;
 477         unsigned short opt_shortname = sbi->options.shortname;
 478         int isvfat = sbi->options.isvfat;
 479         int nocase = sbi->options.nocase;
 480         const char *fill_name = NULL;
 481         unsigned long inum;
 482         unsigned long lpos, dummy, *furrfu = &lpos;
 483         loff_t cpos;
 484         int chi, chl, i, i2, j, last, last_u, dotoffset = 0, fill_len = 0;
 485         int ret = 0;
 486
 487         lock_super(sb);
 488
 489         cpos = filp->f_pos;
 490         /* Fake . and .. for the root directory. */
 491         if (inode->i_ino == MSDOS_ROOT_INO) {
 492                 while (cpos < 2) {
 493                         if (filldir(dirent, "..", cpos+1, cpos, MSDOS_ROOT_INO, DT_DIR) < 0)
 494                                 goto out;
 495                         cpos++;
 496                         filp->f_pos++;
 497                 }
 498                 if (cpos == 2) {
 499                         dummy = 2;
 500                         furrfu = &dummy;
 501                         cpos = 0;
 502                 }
 503         }
 504         if (cpos & (sizeof(struct msdos_dir_entry) - 1)) {
 505                 ret = -ENOENT;
 506                 goto out;
 507         }
 508
 509         bh = NULL;
 510 get_new:
 511         if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
 512                 goto end_of_dir;
 513 parse_record:
 514         nr_slots = 0;
 515         /*
 516          * Check for long filename entry, but if short_only, we don't
 517          * need to parse long filename.
 518          */
 519         if (isvfat && !short_only) {
 520                 if (de->name[0] == DELETED_FLAG)
 521                         goto record_end;
 522                 if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
 523                         goto record_end;
 524                 if (de->attr != ATTR_EXT && IS_FREE(de->name))
 525                         goto record_end;
 526         } else {
 527                 if ((de->attr & ATTR_VOLUME) || IS_FREE(de->name))
 528                         goto record_end;
 529         }
 530
 531         if (isvfat && de->attr == ATTR_EXT) {
 532                 int status = fat_parse_long(inode, &cpos, &bh, &de,
 533                                             &unicode, &nr_slots);
 534                 if (status < 0) {
 535                         filp->f_pos = cpos;
 536                         ret = status;
 537                         goto out;
 538                 } else if (status == PARSE_INVALID)
 539                         goto record_end;
 540                 else if (status == PARSE_NOT_LONGNAME)
 541                         goto parse_record;
 542                 else if (status == PARSE_EOF)
 543                         goto end_of_dir;
 544
 545                 if (nr_slots) {
 546                         void *longname = unicode + FAT_MAX_UNI_CHARS;
 547                         int size = PATH_MAX - FAT_MAX_UNI_SIZE;
 548                         int len = fat_uni_to_x8(sbi, unicode, longname, size);
 549
 550                         fill_name = longname;
 551                         fill_len = len;
 552                         /* !both && !short_only, so we don't need shortname. */
 553                         if (!both)
 554                                 goto start_filldir;
 555                 }
 556         }
 557
 558         if (sbi->options.dotsOK) {
 559                 ptname = bufname;
 560                 dotoffset = 0;
 561                 if (de->attr & ATTR_HIDDEN) {
 562                         *ptname++ = '.';
 563                         dotoffset = 1;
 564                 }
 565         }
 566
 567         memcpy(work, de->name, sizeof(de->name));
 568         /* see namei.c, msdos_format_name */
 569         if (work[0] == 0x05)
 570                 work[0] = 0xE5;
 571         for (i = 0, j = 0, last = 0, last_u = 0; i < 8;) {
 572                 if (!(c = work[i]))
 573                         break;
 574                 chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
 575                                         &bufuname[j++], opt_shortname,
 576                                         de->lcase & CASE_LOWER_BASE);
 577                 if (chl <= 1) {
 578                         ptname[i++] = (!nocase && c>='A' && c<='Z') ? c+32 : c;
 579                         if (c != ' ') {
 580                                 last = i;
 581                                 last_u = j;
 582                         }
 583                 } else {
 584                         last_u = j;
 585                         for (chi = 0; chi < chl && i < 8; chi++) {
 586                                 ptname[i] = work[i];
 587                                 i++; last = i;
 588                         }
 589                 }
 590         }
 591         i = last;
 592         j = last_u;
 593         fat_short2uni(nls_disk, ".", 1, &bufuname[j++]);
 594         ptname[i++] = '.';
 595         for (i2 = 8; i2 < MSDOS_NAME;) {
 596                 if (!(c = work[i2]))
 597                         break;
 598                 chl = fat_shortname2uni(nls_disk, &work[i2], MSDOS_NAME - i2,
 599                                         &bufuname[j++], opt_shortname,
 600                                         de->lcase & CASE_LOWER_EXT);
 601                 if (chl <= 1) {
 602                         i2++;
 603                         ptname[i++] = (!nocase && c>='A' && c<='Z') ? c+32 : c;
 604                         if (c != ' ') {
 605                                 last = i;
 606                                 last_u = j;
 607                         }
 608                 } else {
 609                         last_u = j;
 610                         for (chi = 0; chi < chl && i2 < MSDOS_NAME; chi++) {
 611                                 ptname[i++] = work[i2++];
 612                                 last = i;
 613                         }
 614                 }
 615         }
 616         if (!last)
 617                 goto record_end;
 618
 619         i = last + dotoffset;
 620         j = last_u;
 621
 622         if (isvfat) {
 623                 bufuname[j] = 0x0000;
 624                 i = fat_uni_to_x8(sbi, bufuname, bufname, sizeof(bufname));
 625         }
 626         if (nr_slots) {
 627                 /* hack for fat_ioctl_filldir() */
 628                 struct fat_ioctl_filldir_callback *p = dirent;
 629
 630                 p->longname = fill_name;
 631                 p->long_len = fill_len;
 632                 p->shortname = bufname;
 633                 p->short_len = i;
 634                 fill_name = NULL;
 635                 fill_len = 0;
 636         } else {
 637                 fill_name = bufname;
 638                 fill_len = i;
 639         }
 640
 641 start_filldir:
 642         lpos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry);
 643         if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME))
 644                 inum = inode->i_ino;
 645         else if (!memcmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
 646                 inum = parent_ino(filp->f_path.dentry);
 647         } else {
 648                 loff_t i_pos = fat_make_i_pos(sb, bh, de);
 649                 struct inode *tmp = fat_iget(sb, i_pos);
 650                 if (tmp) {
 651                         inum = tmp->i_ino;
 652                         iput(tmp);
 653                 } else
 654                         inum = iunique(sb, MSDOS_ROOT_INO);
 655         }
 656
 657         if (filldir(dirent, fill_name, fill_len, *furrfu, inum,
 658                     (de->attr & ATTR_DIR) ? DT_DIR : DT_REG) < 0)
 659                 goto fill_failed;
 660
 661 record_end:
 662         furrfu = &lpos;
 663         filp->f_pos = cpos;
 664         goto get_new;
 665 end_of_dir:
 666         filp->f_pos = cpos;
 667 fill_failed:
 668         brelse(bh);
 669         if (unicode)
 670                 __putname(unicode);
 671 out:
 672         unlock_super(sb);
 673         return ret;
 674 }
 675
 676 static int fat_readdir(struct file *filp, void *dirent, filldir_t filldir)
 677 {
 678         struct inode *inode = filp->f_path.dentry->d_inode;
 679         return __fat_readdir(inode, filp, dirent, filldir, 0, 0);
 680 }
 681
 682 #define FAT_IOCTL_FILLDIR_FUNC(func, dirent_type)                          \
 683 static int func(void *__buf, const char *name, int name_len,               \
 684                              loff_t offset, u64 ino, unsigned int d_type)  \
 685 {                                                                          \
 686         struct fat_ioctl_filldir_callback *buf = __buf;                    \
 687         struct dirent_type __user *d1 = buf->dirent;                       \
 688         struct dirent_type __user *d2 = d1 + 1;                            \
 689                                                                            \
 690         if (buf->result)                                                   \
 691                 return -EINVAL;                                            \
 692         buf->result++;                                                     \
 693                                                                            \
 694         if (name != NULL) {                                                \
 695                 /* dirent has only short name */                           \
 696                 if (name_len >= sizeof(d1->d_name))                        \
 697                         name_len = sizeof(d1->d_name) - 1;                 \
 698                                                                            \
 699                 if (put_user(0, d2->d_name)                     ||         \
 700                     put_user(0, &d2->d_reclen)                  ||         \
 701                     copy_to_user(d1->d_name, name, name_len)    ||         \
 702                     put_user(0, d1->d_name + name_len)          ||         \
 703                     put_user(name_len, &d1->d_reclen))                     \
 704                         goto efault;                                       \
 705         } else {                                                           \
 706                 /* dirent has short and long name */                       \
 707                 const char *longname = buf->longname;                      \
 708                 int long_len = buf->long_len;                              \
 709                 const char *shortname = buf->shortname;                    \
 710                 int short_len = buf->short_len;                            \
 711                                                                            \
 712                 if (long_len >= sizeof(d1->d_name))                        \
 713                         long_len = sizeof(d1->d_name) - 1;                 \
 714                 if (short_len >= sizeof(d1->d_name))                       \
 715                         short_len = sizeof(d1->d_name) - 1;                \
 716                                                                            \
 717                 if (copy_to_user(d2->d_name, longname, long_len)        || \
 718                     put_user(0, d2->d_name + long_len)                  || \
 719                     put_user(long_len, &d2->d_reclen)                   || \
 720                     put_user(ino, &d2->d_ino)                           || \
 721                     put_user(offset, &d2->d_off)                        || \
 722                     copy_to_user(d1->d_name, shortname, short_len)      || \
 723                     put_user(0, d1->d_name + short_len)                 || \
 724                     put_user(short_len, &d1->d_reclen))                    \
 725                         goto efault;                                       \
 726         }                                                                  \
 727         return 0;                                                          \
 728 efault:                                                                    \
 729         buf->result = -EFAULT;                                             \
 730         return -EFAULT;                                                    \
 731 }
 732
 733 FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent)
 734
 735 static int fat_ioctl_readdir(struct inode *inode, struct file *filp,
 736                              void __user *dirent, filldir_t filldir,
 737                              int short_only, int both)
 738 {
 739         struct fat_ioctl_filldir_callback buf;
 740         int ret;
 741
 742         buf.dirent = dirent;
 743         buf.result = 0;
 744         mutex_lock(&inode->i_mutex);
 745         ret = -ENOENT;
 746         if (!IS_DEADDIR(inode)) {
 747                 ret = __fat_readdir(inode, filp, &buf, filldir,
 748                                     short_only, both);
 749         }
 750         mutex_unlock(&inode->i_mutex);
 751         if (ret >= 0)
 752                 ret = buf.result;
 753         return ret;
 754 }
 755
 756 static long fat_dir_ioctl(struct file *filp, unsigned int cmd,
 757                           unsigned long arg)
 758 {
 759         struct inode *inode = filp->f_path.dentry->d_inode;
 760         struct __fat_dirent __user *d1 = (struct __fat_dirent __user *)arg;
 761         int short_only, both;
 762
 763         switch (cmd) {
 764         case VFAT_IOCTL_READDIR_SHORT:
 765                 short_only = 1;
 766                 both = 0;
 767                 break;
 768         case VFAT_IOCTL_READDIR_BOTH:
 769                 short_only = 0;
 770                 both = 1;
 771                 break;
 772         default:
 773                 return fat_generic_ioctl(filp, cmd, arg);
 774         }
 775
 776         if (!access_ok(VERIFY_WRITE, d1, sizeof(struct __fat_dirent[2])))
 777                 return -EFAULT;
 778         /*
 779          * Yes, we don't need this put_user() absolutely. However old
 780          * code didn't return the right value. So, app use this value,
 781          * in order to check whether it is EOF.
 782          */
 783         if (put_user(0, &d1->d_reclen))
 784                 return -EFAULT;
 785
 786         return fat_ioctl_readdir(inode, filp, d1, fat_ioctl_filldir,
 787                                  short_only, both);
 788 }
 789
 790 #ifdef CONFIG_COMPAT
 791 #define VFAT_IOCTL_READDIR_BOTH32       _IOR('r', 1, struct compat_dirent[2])
 792 #define VFAT_IOCTL_READDIR_SHORT32      _IOR('r', 2, struct compat_dirent[2])
 793
 794 FAT_IOCTL_FILLDIR_FUNC(fat_compat_ioctl_filldir, compat_dirent)
 795
 796 static long fat_compat_dir_ioctl(struct file *filp, unsigned cmd,
 797                                  unsigned long arg)
 798 {
 799         struct inode *inode = filp->f_path.dentry->d_inode;
 800         struct compat_dirent __user *d1 = compat_ptr(arg);
 801         int short_only, both;
 802
 803         switch (cmd) {
 804         case VFAT_IOCTL_READDIR_SHORT32:
 805                 short_only = 1;
 806                 both = 0;
 807                 break;
 808         case VFAT_IOCTL_READDIR_BOTH32:
 809                 short_only = 0;
 810                 both = 1;
 811                 break;
 812         default:
 813                 return fat_generic_ioctl(filp, cmd, (unsigned long)arg);
 814         }
 815
 816         if (!access_ok(VERIFY_WRITE, d1, sizeof(struct compat_dirent[2])))
 817                 return -EFAULT;
 818         /*
 819          * Yes, we don't need this put_user() absolutely. However old
 820          * code didn't return the right value. So, app use this value,
 821          * in order to check whether it is EOF.
 822          */
 823         if (put_user(0, &d1->d_reclen))
 824                 return -EFAULT;
 825
 826         return fat_ioctl_readdir(inode, filp, d1, fat_compat_ioctl_filldir,
 827                                  short_only, both);
 828 }
 829 #endif /* CONFIG_COMPAT */
 830
 831 const struct file_operations fat_dir_operations = {
 832         .llseek         = generic_file_llseek,
 833         .read           = generic_read_dir,
 834         .readdir        = fat_readdir,
 835         .unlocked_ioctl = fat_dir_ioctl,
 836 #ifdef CONFIG_COMPAT
 837         .compat_ioctl   = fat_compat_dir_ioctl,
 838 #endif
 839         .fsync          = fat_file_fsync,
 840 };
 841
 842 static int fat_get_short_entry(struct inode *dir, loff_t *pos,
 843                                struct buffer_head **bh,
 844                                struct msdos_dir_entry **de)
 845 {
 846         while (fat_get_entry(dir, pos, bh, de) >= 0) {
 847                 /* free entry or long name entry or volume label */
 848                 if (!IS_FREE((*de)->name) && !((*de)->attr & ATTR_VOLUME))
 849                         return 0;
 850         }
 851         return -ENOENT;
 852 }
 853
 854 /*
 855  * The ".." entry can not provide the "struct fat_slot_info" informations
 856  * for inode. So, this function provide the some informations only.
 857  */
 858 int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
 859                          struct msdos_dir_entry **de, loff_t *i_pos)
 860 {
 861         loff_t offset;
 862
 863         offset = 0;
 864         *bh = NULL;
 865         while (fat_get_short_entry(dir, &offset, bh, de) >= 0) {
 866                 if (!strncmp((*de)->name, MSDOS_DOTDOT, MSDOS_NAME)) {
 867                         *i_pos = fat_make_i_pos(dir->i_sb, *bh, *de);
 868                         return 0;
 869                 }
 870         }
 871         return -ENOENT;
 872 }
 873
 874 EXPORT_SYMBOL_GPL(fat_get_dotdot_entry);
 875
 876 /* See if directory is empty */
 877 int fat_dir_empty(struct inode *dir)
 878 {
 879         struct buffer_head *bh;
 880         struct msdos_dir_entry *de;
 881         loff_t cpos;
 882         int result = 0;
 883
 884         bh = NULL;
 885         cpos = 0;
 886         while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
 887                 if (strncmp(de->name, MSDOS_DOT   , MSDOS_NAME) &&
 888                     strncmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
 889                         result = -ENOTEMPTY;
 890                         break;
 891                 }
 892         }
 893         brelse(bh);
 894         return result;
 895 }
 896
 897 EXPORT_SYMBOL_GPL(fat_dir_empty);
 898
 899 /*
 900  * fat_subdirs counts the number of sub-directories of dir. It can be run
 901  * on directories being created.
 902  */
 903 int fat_subdirs(struct inode *dir)
 904 {
 905         struct buffer_head *bh;
 906         struct msdos_dir_entry *de;
 907         loff_t cpos;
 908         int count = 0;
 909
 910         bh = NULL;
 911         cpos = 0;
 912         while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
 913                 if (de->attr & ATTR_DIR)
 914                         count++;
 915         }
 916         brelse(bh);
 917         return count;
 918 }
 919
 920 /*
 921  * Scans a directory for a given file (name points to its formatted name).
 922  * Returns an error code or zero.
 923  */
 924 int fat_scan(struct inode *dir, const unsigned char *name,
 925              struct fat_slot_info *sinfo)
 926 {
 927         struct super_block *sb = dir->i_sb;
 928
 929         sinfo->slot_off = 0;
 930         sinfo->bh = NULL;
 931         while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
 932                                    &sinfo->de) >= 0) {
 933                 if (!strncmp(sinfo->de->name, name, MSDOS_NAME)) {
 934                         sinfo->slot_off -= sizeof(*sinfo->de);
 935                         sinfo->nr_slots = 1;
 936                         sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
 937                         return 0;
 938                 }
 939         }
 940         return -ENOENT;
 941 }
 942
 943 EXPORT_SYMBOL_GPL(fat_scan);
 944
 945 static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots)
 946 {
 947         struct super_block *sb = dir->i_sb;
 948         struct buffer_head *bh;
 949         struct msdos_dir_entry *de, *endp;
 950         int err = 0, orig_slots;
 951
 952         while (nr_slots) {
 953                 bh = NULL;
 954                 if (fat_get_entry(dir, &pos, &bh, &de) < 0) {
 955                         err = -EIO;
 956                         break;
 957                 }
 958
 959                 orig_slots = nr_slots;
 960                 endp = (struct msdos_dir_entry *)(bh->b_data + sb->s_blocksize);
 961                 while (nr_slots && de < endp) {
 962                         de->name[0] = DELETED_FLAG;
 963                         de++;
 964                         nr_slots--;
 965                 }
 966                 mark_buffer_dirty_inode(bh, dir);
 967                 if (IS_DIRSYNC(dir))
 968                         err = sync_dirty_buffer(bh);
 969                 brelse(bh);
 970                 if (err)
 971                         break;
 972
 973                 /* pos is *next* de's position, so this does `- sizeof(de)' */
 974                 pos += ((orig_slots - nr_slots) * sizeof(*de)) - sizeof(*de);
 975         }
 976
 977         return err;
 978 }
 979
 980 int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo)
 981 {
 982         struct msdos_dir_entry *de;
 983         struct buffer_head *bh;
 984         int err = 0, nr_slots;
 985
 986         /*
 987          * First stage: Remove the shortname. By this, the directory
 988          * entry is removed.
 989          */
 990         nr_slots = sinfo->nr_slots;
 991         de = sinfo->de;
 992         sinfo->de = NULL;
 993         bh = sinfo->bh;
 994         sinfo->bh = NULL;
 995         while (nr_slots && de >= (struct msdos_dir_entry *)bh->b_data) {
 996                 de->name[0] = DELETED_FLAG;
 997                 de--;
 998                 nr_slots--;
 999         }
1000         mark_buffer_dirty_inode(bh, dir);
1001         if (IS_DIRSYNC(dir))
1002                 err = sync_dirty_buffer(bh);
1003         brelse(bh);
1004         if (err)
1005                 return err;
1006         dir->i_version++;
1007
1008         if (nr_slots) {
1009                 /*
1010                  * Second stage: remove the remaining longname slots.
1011                  * (This directory entry is already removed, and so return
1012                  * the success)
1013                  */
1014                 err = __fat_remove_entries(dir, sinfo->slot_off, nr_slots);
1015                 if (err) {
1016                         printk(KERN_WARNING
1017                                "FAT: Couldn't remove the long name slots\n");
1018                 }
1019         }
1020
1021         dir->i_mtime = dir->i_atime = CURRENT_TIME_SEC;
1022         if (IS_DIRSYNC(dir))
1023                 (void)fat_sync_inode(dir);
1024         else
1025                 mark_inode_dirty(dir);
1026
1027         return 0;
1028 }
1029
1030 EXPORT_SYMBOL_GPL(fat_remove_entries);
1031
1032 static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used,
1033                               struct buffer_head **bhs, int nr_bhs)
1034 {
1035         struct super_block *sb = dir->i_sb;
1036         sector_t last_blknr = blknr + MSDOS_SB(sb)->sec_per_clus;
1037         int err, i, n;
1038
1039         /* Zeroing the unused blocks on this cluster */
1040         blknr += nr_used;
1041         n = nr_used;
1042         while (blknr < last_blknr) {
1043                 bhs[n] = sb_getblk(sb, blknr);
1044                 if (!bhs[n]) {
1045                         err = -ENOMEM;
1046                         goto error;
1047                 }
1048                 memset(bhs[n]->b_data, 0, sb->s_blocksize);
1049                 set_buffer_uptodate(bhs[n]);
1050                 mark_buffer_dirty_inode(bhs[n], dir);
1051
1052                 n++;
1053                 blknr++;
1054                 if (n == nr_bhs) {
1055                         if (IS_DIRSYNC(dir)) {
1056                                 err = fat_sync_bhs(bhs, n);
1057                                 if (err)
1058                                         goto error;
1059                         }
1060                         for (i = 0; i < n; i++)
1061                                 brelse(bhs[i]);
1062                         n = 0;
1063                 }
1064         }
1065         if (IS_DIRSYNC(dir)) {
1066                 err = fat_sync_bhs(bhs, n);
1067                 if (err)
1068                         goto error;
1069         }
1070         for (i = 0; i < n; i++)
1071                 brelse(bhs[i]);
1072
1073         return 0;
1074
1075 error:
1076         for (i = 0; i < n; i++)
1077                 bforget(bhs[i]);
1078         return err;
1079 }
1080
1081 int fat_alloc_new_dir(struct inode *dir, struct timespec *ts)
1082 {
1083         struct super_block *sb = dir->i_sb;
1084         struct msdos_sb_info *sbi = MSDOS_SB(sb);
1085         struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1086         struct msdos_dir_entry *de;
1087         sector_t blknr;
1088         __le16 date, time;
1089         u8 time_cs;
1090         int err, cluster;
1091
1092         err = fat_alloc_clusters(dir, &cluster, 1);
1093         if (err)
1094                 goto error;
1095
1096         blknr = fat_clus_to_blknr(sbi, cluster);
1097         bhs[0] = sb_getblk(sb, blknr);
1098         if (!bhs[0]) {
1099                 err = -ENOMEM;
1100                 goto error_free;
1101         }
1102
1103         fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
1104
1105         de = (struct msdos_dir_entry *)bhs[0]->b_data;
1106         /* filling the new directory slots ("." and ".." entries) */
1107         memcpy(de[0].name, MSDOS_DOT, MSDOS_NAME);
1108         memcpy(de[1].name, MSDOS_DOTDOT, MSDOS_NAME);
1109         de->attr = de[1].attr = ATTR_DIR;
1110         de[0].lcase = de[1].lcase = 0;
1111         de[0].time = de[1].time = time;
1112         de[0].date = de[1].date = date;
1113         if (sbi->options.isvfat) {
1114                 /* extra timestamps */
1115                 de[0].ctime = de[1].ctime = time;
1116                 de[0].ctime_cs = de[1].ctime_cs = time_cs;
1117                 de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = date;
1118         } else {
1119                 de[0].ctime = de[1].ctime = 0;
1120                 de[0].ctime_cs = de[1].ctime_cs = 0;
1121                 de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = 0;
1122         }
1123         de[0].start = cpu_to_le16(cluster);
1124         de[0].starthi = cpu_to_le16(cluster >> 16);
1125         de[1].start = cpu_to_le16(MSDOS_I(dir)->i_logstart);
1126         de[1].starthi = cpu_to_le16(MSDOS_I(dir)->i_logstart >> 16);
1127         de[0].size = de[1].size = 0;
1128         memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de));
1129         set_buffer_uptodate(bhs[0]);
1130         mark_buffer_dirty_inode(bhs[0], dir);
1131
1132         err = fat_zeroed_cluster(dir, blknr, 1, bhs, MAX_BUF_PER_PAGE);
1133         if (err)
1134                 goto error_free;
1135
1136         return cluster;
1137
1138 error_free:
1139         fat_free_clusters(dir, cluster);
1140 error:
1141         return err;
1142 }
1143
1144 EXPORT_SYMBOL_GPL(fat_alloc_new_dir);
1145
1146 static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots,
1147                                int *nr_cluster, struct msdos_dir_entry **de,
1148                                struct buffer_head **bh, loff_t *i_pos)
1149 {
1150         struct super_block *sb = dir->i_sb;
1151         struct msdos_sb_info *sbi = MSDOS_SB(sb);
1152         struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1153         sector_t blknr, start_blknr, last_blknr;
1154         unsigned long size, copy;
1155         int err, i, n, offset, cluster[2];
1156
1157         /*
1158          * The minimum cluster size is 512bytes, and maximum entry
1159          * size is 32*slots (672bytes).  So, iff the cluster size is
1160          * 512bytes, we may need two clusters.
1161          */
1162         size = nr_slots * sizeof(struct msdos_dir_entry);
1163         *nr_cluster = (size + (sbi->cluster_size - 1)) >> sbi->cluster_bits;
1164         BUG_ON(*nr_cluster > 2);
1165
1166         err = fat_alloc_clusters(dir, cluster, *nr_cluster);
1167         if (err)
1168                 goto error;
1169
1170         /*
1171          * First stage: Fill the directory entry.  NOTE: This cluster
1172          * is not referenced from any inode yet, so updates order is
1173          * not important.
1174          */
1175         i = n = copy = 0;
1176         do {
1177                 start_blknr = blknr = fat_clus_to_blknr(sbi, cluster[i]);
1178                 last_blknr = start_blknr + sbi->sec_per_clus;
1179                 while (blknr < last_blknr) {
1180                         bhs[n] = sb_getblk(sb, blknr);
1181                         if (!bhs[n]) {
1182                                 err = -ENOMEM;
1183                                 goto error_nomem;
1184                         }
1185
1186                         /* fill the directory entry */
1187                         copy = min(size, sb->s_blocksize);
1188                         memcpy(bhs[n]->b_data, slots, copy);
1189                         slots += copy;
1190                         size -= copy;
1191                         set_buffer_uptodate(bhs[n]);
1192                         mark_buffer_dirty_inode(bhs[n], dir);
1193                         if (!size)
1194                                 break;
1195                         n++;
1196                         blknr++;
1197                 }
1198         } while (++i < *nr_cluster);
1199
1200         memset(bhs[n]->b_data + copy, 0, sb->s_blocksize - copy);
1201         offset = copy - sizeof(struct msdos_dir_entry);
1202         get_bh(bhs[n]);
1203         *bh = bhs[n];
1204         *de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
1205         *i_pos = fat_make_i_pos(sb, *bh, *de);
1206
1207         /* Second stage: clear the rest of cluster, and write outs */
1208         err = fat_zeroed_cluster(dir, start_blknr, ++n, bhs, MAX_BUF_PER_PAGE);
1209         if (err)
1210                 goto error_free;
1211
1212         return cluster[0];
1213
1214 error_free:
1215         brelse(*bh);
1216         *bh = NULL;
1217         n = 0;
1218 error_nomem:
1219         for (i = 0; i < n; i++)
1220                 bforget(bhs[i]);
1221         fat_free_clusters(dir, cluster[0]);
1222 error:
1223         return err;
1224 }
1225
1226 int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
1227                     struct fat_slot_info *sinfo)
1228 {
1229         struct super_block *sb = dir->i_sb;
1230         struct msdos_sb_info *sbi = MSDOS_SB(sb);
1231         struct buffer_head *bh, *prev, *bhs[3]; /* 32*slots (672bytes) */
1232         struct msdos_dir_entry *de;
1233         int err, free_slots, i, nr_bhs;
1234         loff_t pos, i_pos;
1235
1236         sinfo->nr_slots = nr_slots;
1237
1238         /* First stage: search free direcotry entries */
1239         free_slots = nr_bhs = 0;
1240         bh = prev = NULL;
1241         pos = 0;
1242         err = -ENOSPC;
1243         while (fat_get_entry(dir, &pos, &bh, &de) > -1) {
1244                 /* check the maximum size of directory */
1245                 if (pos >= FAT_MAX_DIR_SIZE)
1246                         goto error;
1247
1248                 if (IS_FREE(de->name)) {
1249                         if (prev != bh) {
1250                                 get_bh(bh);
1251                                 bhs[nr_bhs] = prev = bh;
1252                                 nr_bhs++;
1253                         }
1254                         free_slots++;
1255                         if (free_slots == nr_slots)
1256                                 goto found;
1257                 } else {
1258                         for (i = 0; i < nr_bhs; i++)
1259                                 brelse(bhs[i]);
1260                         prev = NULL;
1261                         free_slots = nr_bhs = 0;
1262                 }
1263         }
1264         if (dir->i_ino == MSDOS_ROOT_INO) {
1265                 if (sbi->fat_bits != 32)
1266                         goto error;
1267         } else if (MSDOS_I(dir)->i_start == 0) {
1268                 printk(KERN_ERR "FAT: Corrupted directory (i_pos %lld)\n",
1269                        MSDOS_I(dir)->i_pos);
1270                 err = -EIO;
1271                 goto error;
1272         }
1273
1274 found:
1275         err = 0;
1276         pos -= free_slots * sizeof(*de);
1277         nr_slots -= free_slots;
1278         if (free_slots) {
1279                 /*
1280                  * Second stage: filling the free entries with new entries.
1281                  * NOTE: If this slots has shortname, first, we write
1282                  * the long name slots, then write the short name.
1283                  */
1284                 int size = free_slots * sizeof(*de);
1285                 int offset = pos & (sb->s_blocksize - 1);
1286                 int long_bhs = nr_bhs - (nr_slots == 0);
1287
1288                 /* Fill the long name slots. */
1289                 for (i = 0; i < long_bhs; i++) {
1290                         int copy = min_t(int, sb->s_blocksize - offset, size);
1291                         memcpy(bhs[i]->b_data + offset, slots, copy);
1292                         mark_buffer_dirty_inode(bhs[i], dir);
1293                         offset = 0;
1294                         slots += copy;
1295                         size -= copy;
1296                 }
1297                 if (long_bhs && IS_DIRSYNC(dir))
1298                         err = fat_sync_bhs(bhs, long_bhs);
1299                 if (!err && i < nr_bhs) {
1300                         /* Fill the short name slot. */
1301                         int copy = min_t(int, sb->s_blocksize - offset, size);
1302                         memcpy(bhs[i]->b_data + offset, slots, copy);
1303                         mark_buffer_dirty_inode(bhs[i], dir);
1304                         if (IS_DIRSYNC(dir))
1305                                 err = sync_dirty_buffer(bhs[i]);
1306                 }
1307                 for (i = 0; i < nr_bhs; i++)
1308                         brelse(bhs[i]);
1309                 if (err)
1310                         goto error_remove;
1311         }
1312
1313         if (nr_slots) {
1314                 int cluster, nr_cluster;
1315
1316                 /*
1317                  * Third stage: allocate the cluster for new entries.
1318                  * And initialize the cluster with new entries, then
1319                  * add the cluster to dir.
1320                  */
1321                 cluster = fat_add_new_entries(dir, slots, nr_slots, &nr_cluster,
1322                                               &de, &bh, &i_pos);
1323                 if (cluster < 0) {
1324                         err = cluster;
1325                         goto error_remove;
1326                 }
1327                 err = fat_chain_add(dir, cluster, nr_cluster);
1328                 if (err) {
1329                         fat_free_clusters(dir, cluster);
1330                         goto error_remove;
1331                 }
1332                 if (dir->i_size & (sbi->cluster_size - 1)) {
1333                         fat_fs_error(sb, "Odd directory size");
1334                         dir->i_size = (dir->i_size + sbi->cluster_size - 1)
1335                                 & ~((loff_t)sbi->cluster_size - 1);
1336                 }
1337                 dir->i_size += nr_cluster << sbi->cluster_bits;
1338                 MSDOS_I(dir)->mmu_private += nr_cluster << sbi->cluster_bits;
1339         }
1340         sinfo->slot_off = pos;
1341         sinfo->de = de;
1342         sinfo->bh = bh;
1343         sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
1344
1345         return 0;
1346
1347 error:
1348         brelse(bh);
1349         for (i = 0; i < nr_bhs; i++)
1350                 brelse(bhs[i]);
1351         return err;
1352
1353 error_remove:
1354         brelse(bh);
1355         if (free_slots)
1356                 __fat_remove_entries(dir, pos, free_slots);
1357         return err;
1358 }
1359
1360 EXPORT_SYMBOL_GPL(fat_add_entries);