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                 fat_msg(sb, KERN_ERR, "Directory bread(block %llu) failed",
 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(struct super_block *sb, unsigned char *ascii,
 140                        const wchar_t *uni, int len, struct nls_table *nls)
 141 {
 142         int uni_xlate = MSDOS_SB(sb)->options.unicode_xlate;
 143         const wchar_t *ip;
 144         wchar_t ec;
 145         unsigned char *op;
 146         int charlen;
 147
 148         ip = uni;
 149         op = ascii;
 150
 151         while (*ip && ((len - NLS_MAX_CHARSET_SIZE) > 0)) {
 152                 ec = *ip++;
 153                 if ((charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE)) > 0) {
 154                         op += charlen;
 155                         len -= charlen;
 156                 } else {
 157                         if (uni_xlate == 1) {
 158                                 *op++ = ':';
 159                                 op = hex_byte_pack(op, ec >> 8);
 160                                 op = hex_byte_pack(op, ec);
 161                                 len -= 5;
 162                         } else {
 163                                 *op++ = '?';
 164                                 len--;
 165                         }
 166                 }
 167         }
 168
 169         if (unlikely(*ip)) {
 170                 fat_msg(sb, KERN_WARNING, "filename was truncated while "
 171                         "converting.");
 172         }
 173
 174         *op = 0;
 175         return (op - ascii);
 176 }
 177
 178 static inline int fat_uni_to_x8(struct super_block *sb, const wchar_t *uni,
 179                                 unsigned char *buf, int size)
 180 {
 181         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 182         if (sbi->options.utf8)
 183                 return utf16s_to_utf8s(uni, FAT_MAX_UNI_CHARS,
 184                                 UTF16_HOST_ENDIAN, buf, size);
 185         else
 186                 return uni16_to_x8(sb, buf, uni, size, sbi->nls_io);
 187 }
 188
 189 static inline int
 190 fat_short2uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
 191 {
 192         int charlen;
 193
 194         charlen = t->char2uni(c, clen, uni);
 195         if (charlen < 0) {
 196                 *uni = 0x003f;  /* a question mark */
 197                 charlen = 1;
 198         }
 199         return charlen;
 200 }
 201
 202 static inline int
 203 fat_short2lower_uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
 204 {
 205         int charlen;
 206         wchar_t wc;
 207
 208         charlen = t->char2uni(c, clen, &wc);
 209         if (charlen < 0) {
 210                 *uni = 0x003f;  /* a question mark */
 211                 charlen = 1;
 212         } else if (charlen <= 1) {
 213                 unsigned char nc = t->charset2lower[*c];
 214
 215                 if (!nc)
 216                         nc = *c;
 217
 218                 if ( (charlen = t->char2uni(&nc, 1, uni)) < 0) {
 219                         *uni = 0x003f;  /* a question mark */
 220                         charlen = 1;
 221                 }
 222         } else
 223                 *uni = wc;
 224
 225         return charlen;
 226 }
 227
 228 static inline int
 229 fat_shortname2uni(struct nls_table *nls, unsigned char *buf, int buf_size,
 230                   wchar_t *uni_buf, unsigned short opt, int lower)
 231 {
 232         int len = 0;
 233
 234         if (opt & VFAT_SFN_DISPLAY_LOWER)
 235                 len =  fat_short2lower_uni(nls, buf, buf_size, uni_buf);
 236         else if (opt & VFAT_SFN_DISPLAY_WIN95)
 237                 len = fat_short2uni(nls, buf, buf_size, uni_buf);
 238         else if (opt & VFAT_SFN_DISPLAY_WINNT) {
 239                 if (lower)
 240                         len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);
 241                 else
 242                         len = fat_short2uni(nls, buf, buf_size, uni_buf);
 243         } else
 244                 len = fat_short2uni(nls, buf, buf_size, uni_buf);
 245
 246         return len;
 247 }
 248
 249 static inline int fat_name_match(struct msdos_sb_info *sbi,
 250                                  const unsigned char *a, int a_len,
 251                                  const unsigned char *b, int b_len)
 252 {
 253         if (a_len != b_len)
 254                 return 0;
 255
 256         if (sbi->options.name_check != 's')
 257                 return !nls_strnicmp(sbi->nls_io, a, b, a_len);
 258         else
 259                 return !memcmp(a, b, a_len);
 260 }
 261
 262 enum { PARSE_INVALID = 1, PARSE_NOT_LONGNAME, PARSE_EOF, };
 263
 264 /**
 265  * fat_parse_long - Parse extended directory entry.
 266  *
 267  * This function returns zero on success, negative value on error, or one of
 268  * the following:
 269  *
 270  * %PARSE_INVALID - Directory entry is invalid.
 271  * %PARSE_NOT_LONGNAME - Directory entry does not contain longname.
 272  * %PARSE_EOF - Directory has no more entries.
 273  */
 274 static int fat_parse_long(struct inode *dir, loff_t *pos,
 275                           struct buffer_head **bh, struct msdos_dir_entry **de,
 276                           wchar_t **unicode, unsigned char *nr_slots)
 277 {
 278         struct msdos_dir_slot *ds;
 279         unsigned char id, slot, slots, alias_checksum;
 280
 281         if (!*unicode) {
 282                 *unicode = __getname();
 283                 if (!*unicode) {
 284                         brelse(*bh);
 285                         return -ENOMEM;
 286                 }
 287         }
 288 parse_long:
 289         slots = 0;
 290         ds = (struct msdos_dir_slot *)*de;
 291         id = ds->id;
 292         if (!(id & 0x40))
 293                 return PARSE_INVALID;
 294         slots = id & ~0x40;
 295         if (slots > 20 || !slots)       /* ceil(256 * 2 / 26) */
 296                 return PARSE_INVALID;
 297         *nr_slots = slots;
 298         alias_checksum = ds->alias_checksum;
 299
 300         slot = slots;
 301         while (1) {
 302                 int offset;
 303
 304                 slot--;
 305                 offset = slot * 13;
 306                 fat16_towchar(*unicode + offset, ds->name0_4, 5);
 307                 fat16_towchar(*unicode + offset + 5, ds->name5_10, 6);
 308                 fat16_towchar(*unicode + offset + 11, ds->name11_12, 2);
 309
 310                 if (ds->id & 0x40)
 311                         (*unicode)[offset + 13] = 0;
 312                 if (fat_get_entry(dir, pos, bh, de) < 0)
 313                         return PARSE_EOF;
 314                 if (slot == 0)
 315                         break;
 316                 ds = (struct msdos_dir_slot *)*de;
 317                 if (ds->attr != ATTR_EXT)
 318                         return PARSE_NOT_LONGNAME;
 319                 if ((ds->id & ~0x40) != slot)
 320                         goto parse_long;
 321                 if (ds->alias_checksum != alias_checksum)
 322                         goto parse_long;
 323         }
 324         if ((*de)->name[0] == DELETED_FLAG)
 325                 return PARSE_INVALID;
 326         if ((*de)->attr == ATTR_EXT)
 327                 goto parse_long;
 328         if (IS_FREE((*de)->name) || ((*de)->attr & ATTR_VOLUME))
 329                 return PARSE_INVALID;
 330         if (fat_checksum((*de)->name) != alias_checksum)
 331                 *nr_slots = 0;
 332
 333         return 0;
 334 }
 335
 336 /*
 337  * Return values: negative -> error, 0 -> not found, positive -> found,
 338  * value is the total amount of slots, including the shortname entry.
 339  */
 340 int fat_search_long(struct inode *inode, const unsigned char *name,
 341                     int name_len, struct fat_slot_info *sinfo)
 342 {
 343         struct super_block *sb = inode->i_sb;
 344         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 345         struct buffer_head *bh = NULL;
 346         struct msdos_dir_entry *de;
 347         struct nls_table *nls_disk = sbi->nls_disk;
 348         unsigned char nr_slots;
 349         wchar_t bufuname[14];
 350         wchar_t *unicode = NULL;
 351         unsigned char work[MSDOS_NAME];
 352         unsigned char bufname[FAT_MAX_SHORT_SIZE];
 353         unsigned short opt_shortname = sbi->options.shortname;
 354         loff_t cpos = 0;
 355         int chl, i, j, last_u, err, len;
 356
 357         err = -ENOENT;
 358         while (1) {
 359                 if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
 360                         goto end_of_dir;
 361 parse_record:
 362                 nr_slots = 0;
 363                 if (de->name[0] == DELETED_FLAG)
 364                         continue;
 365                 if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
 366                         continue;
 367                 if (de->attr != ATTR_EXT && IS_FREE(de->name))
 368                         continue;
 369                 if (de->attr == ATTR_EXT) {
 370                         int status = fat_parse_long(inode, &cpos, &bh, &de,
 371                                                     &unicode, &nr_slots);
 372                         if (status < 0) {
 373                                 err = status;
 374                                 goto end_of_dir;
 375                         } else if (status == PARSE_INVALID)
 376                                 continue;
 377                         else if (status == PARSE_NOT_LONGNAME)
 378                                 goto parse_record;
 379                         else if (status == PARSE_EOF)
 380                                 goto end_of_dir;
 381                 }
 382
 383                 memcpy(work, de->name, sizeof(de->name));
 384                 /* see namei.c, msdos_format_name */
 385                 if (work[0] == 0x05)
 386                         work[0] = 0xE5;
 387                 for (i = 0, j = 0, last_u = 0; i < 8;) {
 388                         if (!work[i])
 389                                 break;
 390                         chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
 391                                                 &bufuname[j++], opt_shortname,
 392                                                 de->lcase & CASE_LOWER_BASE);
 393                         if (chl <= 1) {
 394                                 if (work[i] != ' ')
 395                                         last_u = j;
 396                         } else {
 397                                 last_u = j;
 398                         }
 399                         i += chl;
 400                 }
 401                 j = last_u;
 402                 fat_short2uni(nls_disk, ".", 1, &bufuname[j++]);
 403                 for (i = 8; i < MSDOS_NAME;) {
 404                         if (!work[i])
 405                                 break;
 406                         chl = fat_shortname2uni(nls_disk, &work[i],
 407                                                 MSDOS_NAME - i,
 408                                                 &bufuname[j++], opt_shortname,
 409                                                 de->lcase & CASE_LOWER_EXT);
 410                         if (chl <= 1) {
 411                                 if (work[i] != ' ')
 412                                         last_u = j;
 413                         } else {
 414                                 last_u = j;
 415                         }
 416                         i += chl;
 417                 }
 418                 if (!last_u)
 419                         continue;
 420
 421                 /* Compare shortname */
 422                 bufuname[last_u] = 0x0000;
 423                 len = fat_uni_to_x8(sb, bufuname, bufname, sizeof(bufname));
 424                 if (fat_name_match(sbi, name, name_len, bufname, len))
 425                         goto found;
 426
 427                 if (nr_slots) {
 428                         void *longname = unicode + FAT_MAX_UNI_CHARS;
 429                         int size = PATH_MAX - FAT_MAX_UNI_SIZE;
 430
 431                         /* Compare longname */
 432                         len = fat_uni_to_x8(sb, unicode, longname, size);
 433                         if (fat_name_match(sbi, name, name_len, longname, len))
 434                                 goto found;
 435                 }
 436         }
 437
 438 found:
 439         nr_slots++;     /* include the de */
 440         sinfo->slot_off = cpos - nr_slots * sizeof(*de);
 441         sinfo->nr_slots = nr_slots;
 442         sinfo->de = de;
 443         sinfo->bh = bh;
 444         sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
 445         err = 0;
 446 end_of_dir:
 447         if (unicode)
 448                 __putname(unicode);
 449
 450         return err;
 451 }
 452
 453 EXPORT_SYMBOL_GPL(fat_search_long);
 454
 455 struct fat_ioctl_filldir_callback {
 456         void __user *dirent;
 457         int result;
 458         /* for dir ioctl */
 459         const char *longname;
 460         int long_len;
 461         const char *shortname;
 462         int short_len;
 463 };
 464
 465 static int __fat_readdir(struct inode *inode, struct file *filp, void *dirent,
 466                          filldir_t filldir, int short_only, int both)
 467 {
 468         struct super_block *sb = inode->i_sb;
 469         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 470         struct buffer_head *bh;
 471         struct msdos_dir_entry *de;
 472         struct nls_table *nls_disk = sbi->nls_disk;
 473         unsigned char nr_slots;
 474         wchar_t bufuname[14];
 475         wchar_t *unicode = NULL;
 476         unsigned char c, work[MSDOS_NAME];
 477         unsigned char bufname[FAT_MAX_SHORT_SIZE], *ptname = bufname;
 478         unsigned short opt_shortname = sbi->options.shortname;
 479         int isvfat = sbi->options.isvfat;
 480         int nocase = sbi->options.nocase;
 481         const char *fill_name = NULL;
 482         unsigned long inum;
 483         unsigned long lpos, dummy, *furrfu = &lpos;
 484         loff_t cpos;
 485         int chi, chl, i, i2, j, last, last_u, dotoffset = 0, fill_len = 0;
 486         int ret = 0;
 487
 488         lock_super(sb);
 489
 490         cpos = filp->f_pos;
 491         /* Fake . and .. for the root directory. */
 492         if (inode->i_ino == MSDOS_ROOT_INO) {
 493                 while (cpos < 2) {
 494                         if (filldir(dirent, "..", cpos+1, cpos, MSDOS_ROOT_INO, DT_DIR) < 0)
 495                                 goto out;
 496                         cpos++;
 497                         filp->f_pos++;
 498                 }
 499                 if (cpos == 2) {
 500                         dummy = 2;
 501                         furrfu = &dummy;
 502                         cpos = 0;
 503                 }
 504         }
 505         if (cpos & (sizeof(struct msdos_dir_entry) - 1)) {
 506                 ret = -ENOENT;
 507                 goto out;
 508         }
 509
 510         bh = NULL;
 511 get_new:
 512         if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
 513                 goto end_of_dir;
 514 parse_record:
 515         nr_slots = 0;
 516         /*
 517          * Check for long filename entry, but if short_only, we don't
 518          * need to parse long filename.
 519          */
 520         if (isvfat && !short_only) {
 521                 if (de->name[0] == DELETED_FLAG)
 522                         goto record_end;
 523                 if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
 524                         goto record_end;
 525                 if (de->attr != ATTR_EXT && IS_FREE(de->name))
 526                         goto record_end;
 527         } else {
 528                 if ((de->attr & ATTR_VOLUME) || IS_FREE(de->name))
 529                         goto record_end;
 530         }
 531
 532         if (isvfat && de->attr == ATTR_EXT) {
 533                 int status = fat_parse_long(inode, &cpos, &bh, &de,
 534                                             &unicode, &nr_slots);
 535                 if (status < 0) {
 536                         filp->f_pos = cpos;
 537                         ret = status;
 538                         goto out;
 539                 } else if (status == PARSE_INVALID)
 540                         goto record_end;
 541                 else if (status == PARSE_NOT_LONGNAME)
 542                         goto parse_record;
 543                 else if (status == PARSE_EOF)
 544                         goto end_of_dir;
 545
 546                 if (nr_slots) {
 547                         void *longname = unicode + FAT_MAX_UNI_CHARS;
 548                         int size = PATH_MAX - FAT_MAX_UNI_SIZE;
 549                         int len = fat_uni_to_x8(sb, unicode, longname, size);
 550
 551                         fill_name = longname;
 552                         fill_len = len;
 553                         /* !both && !short_only, so we don't need shortname. */
 554                         if (!both)
 555                                 goto start_filldir;
 556                 }
 557         }
 558
 559         if (sbi->options.dotsOK) {
 560                 ptname = bufname;
 561                 dotoffset = 0;
 562                 if (de->attr & ATTR_HIDDEN) {
 563                         *ptname++ = '.';
 564                         dotoffset = 1;
 565                 }
 566         }
 567
 568         memcpy(work, de->name, sizeof(de->name));
 569         /* see namei.c, msdos_format_name */
 570         if (work[0] == 0x05)
 571                 work[0] = 0xE5;
 572         for (i = 0, j = 0, last = 0, last_u = 0; i < 8;) {
 573                 if (!(c = work[i]))
 574                         break;
 575                 chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
 576                                         &bufuname[j++], opt_shortname,
 577                                         de->lcase & CASE_LOWER_BASE);
 578                 if (chl <= 1) {
 579                         ptname[i++] = (!nocase && c>='A' && c<='Z') ? c+32 : c;
 580                         if (c != ' ') {
 581                                 last = i;
 582                                 last_u = j;
 583                         }
 584                 } else {
 585                         last_u = j;
 586                         for (chi = 0; chi < chl && i < 8; chi++) {
 587                                 ptname[i] = work[i];
 588                                 i++; last = i;
 589                         }
 590                 }
 591         }
 592         i = last;
 593         j = last_u;
 594         fat_short2uni(nls_disk, ".", 1, &bufuname[j++]);
 595         ptname[i++] = '.';
 596         for (i2 = 8; i2 < MSDOS_NAME;) {
 597                 if (!(c = work[i2]))
 598                         break;
 599                 chl = fat_shortname2uni(nls_disk, &work[i2], MSDOS_NAME - i2,
 600                                         &bufuname[j++], opt_shortname,
 601                                         de->lcase & CASE_LOWER_EXT);
 602                 if (chl <= 1) {
 603                         i2++;
 604                         ptname[i++] = (!nocase && c>='A' && c<='Z') ? c+32 : c;
 605                         if (c != ' ') {
 606                                 last = i;
 607                                 last_u = j;
 608                         }
 609                 } else {
 610                         last_u = j;
 611                         for (chi = 0; chi < chl && i2 < MSDOS_NAME; chi++) {
 612                                 ptname[i++] = work[i2++];
 613                                 last = i;
 614                         }
 615                 }
 616         }
 617         if (!last)
 618                 goto record_end;
 619
 620         i = last + dotoffset;
 621         j = last_u;
 622
 623         if (isvfat) {
 624                 bufuname[j] = 0x0000;
 625                 i = fat_uni_to_x8(sb, bufuname, bufname, sizeof(bufname));
 626         }
 627         if (nr_slots) {
 628                 /* hack for fat_ioctl_filldir() */
 629                 struct fat_ioctl_filldir_callback *p = dirent;
 630
 631                 p->longname = fill_name;
 632                 p->long_len = fill_len;
 633                 p->shortname = bufname;
 634                 p->short_len = i;
 635                 fill_name = NULL;
 636                 fill_len = 0;
 637         } else {
 638                 fill_name = bufname;
 639                 fill_len = i;
 640         }
 641
 642 start_filldir:
 643         lpos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry);
 644         if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME))
 645                 inum = inode->i_ino;
 646         else if (!memcmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
 647                 inum = parent_ino(filp->f_path.dentry);
 648         } else {
 649                 loff_t i_pos = fat_make_i_pos(sb, bh, de);
 650                 struct inode *tmp = fat_iget(sb, i_pos);
 651                 if (tmp) {
 652                         inum = tmp->i_ino;
 653                         iput(tmp);
 654                 } else
 655                         inum = iunique(sb, MSDOS_ROOT_INO);
 656         }
 657
 658         if (filldir(dirent, fill_name, fill_len, *furrfu, inum,
 659                     (de->attr & ATTR_DIR) ? DT_DIR : DT_REG) < 0)
 660                 goto fill_failed;
 661
 662 record_end:
 663         furrfu = &lpos;
 664         filp->f_pos = cpos;
 665         goto get_new;
 666 end_of_dir:
 667         filp->f_pos = cpos;
 668 fill_failed:
 669         brelse(bh);
 670         if (unicode)
 671                 __putname(unicode);
 672 out:
 673         unlock_super(sb);
 674         return ret;
 675 }
 676
 677 static int fat_readdir(struct file *filp, void *dirent, filldir_t filldir)
 678 {
 679         struct inode *inode = filp->f_path.dentry->d_inode;
 680         return __fat_readdir(inode, filp, dirent, filldir, 0, 0);
 681 }
 682
 683 #define FAT_IOCTL_FILLDIR_FUNC(func, dirent_type)                          \
 684 static int func(void *__buf, const char *name, int name_len,               \
 685                              loff_t offset, u64 ino, unsigned int d_type)  \
 686 {                                                                          \
 687         struct fat_ioctl_filldir_callback *buf = __buf;                    \
 688         struct dirent_type __user *d1 = buf->dirent;                       \
 689         struct dirent_type __user *d2 = d1 + 1;                            \
 690                                                                            \
 691         if (buf->result)                                                   \
 692                 return -EINVAL;                                            \
 693         buf->result++;                                                     \
 694                                                                            \
 695         if (name != NULL) {                                                \
 696                 /* dirent has only short name */                           \
 697                 if (name_len >= sizeof(d1->d_name))                        \
 698                         name_len = sizeof(d1->d_name) - 1;                 \
 699                                                                            \
 700                 if (put_user(0, d2->d_name)                     ||         \
 701                     put_user(0, &d2->d_reclen)                  ||         \
 702                     copy_to_user(d1->d_name, name, name_len)    ||         \
 703                     put_user(0, d1->d_name + name_len)          ||         \
 704                     put_user(name_len, &d1->d_reclen))                     \
 705                         goto efault;                                       \
 706         } else {                                                           \
 707                 /* dirent has short and long name */                       \
 708                 const char *longname = buf->longname;                      \
 709                 int long_len = buf->long_len;                              \
 710                 const char *shortname = buf->shortname;                    \
 711                 int short_len = buf->short_len;                            \
 712                                                                            \
 713                 if (long_len >= sizeof(d1->d_name))                        \
 714                         long_len = sizeof(d1->d_name) - 1;                 \
 715                 if (short_len >= sizeof(d1->d_name))                       \
 716                         short_len = sizeof(d1->d_name) - 1;                \
 717                                                                            \
 718                 if (copy_to_user(d2->d_name, longname, long_len)        || \
 719                     put_user(0, d2->d_name + long_len)                  || \
 720                     put_user(long_len, &d2->d_reclen)                   || \
 721                     put_user(ino, &d2->d_ino)                           || \
 722                     put_user(offset, &d2->d_off)                        || \
 723                     copy_to_user(d1->d_name, shortname, short_len)      || \
 724                     put_user(0, d1->d_name + short_len)                 || \
 725                     put_user(short_len, &d1->d_reclen))                    \
 726                         goto efault;                                       \
 727         }                                                                  \
 728         return 0;                                                          \
 729 efault:                                                                    \
 730         buf->result = -EFAULT;                                             \
 731         return -EFAULT;                                                    \
 732 }
 733
 734 FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent)
 735
 736 static int fat_ioctl_readdir(struct inode *inode, struct file *filp,
 737                              void __user *dirent, filldir_t filldir,
 738                              int short_only, int both)
 739 {
 740         struct fat_ioctl_filldir_callback buf;
 741         int ret;
 742
 743         buf.dirent = dirent;
 744         buf.result = 0;
 745         mutex_lock(&inode->i_mutex);
 746         ret = -ENOENT;
 747         if (!IS_DEADDIR(inode)) {
 748                 ret = __fat_readdir(inode, filp, &buf, filldir,
 749                                     short_only, both);
 750         }
 751         mutex_unlock(&inode->i_mutex);
 752         if (ret >= 0)
 753                 ret = buf.result;
 754         return ret;
 755 }
 756
 757 static long fat_dir_ioctl(struct file *filp, unsigned int cmd,
 758                           unsigned long arg)
 759 {
 760         struct inode *inode = filp->f_path.dentry->d_inode;
 761         struct __fat_dirent __user *d1 = (struct __fat_dirent __user *)arg;
 762         int short_only, both;
 763
 764         switch (cmd) {
 765         case VFAT_IOCTL_READDIR_SHORT:
 766                 short_only = 1;
 767                 both = 0;
 768                 break;
 769         case VFAT_IOCTL_READDIR_BOTH:
 770                 short_only = 0;
 771                 both = 1;
 772                 break;
 773         default:
 774                 return fat_generic_ioctl(filp, cmd, arg);
 775         }
 776
 777         if (!access_ok(VERIFY_WRITE, d1, sizeof(struct __fat_dirent[2])))
 778                 return -EFAULT;
 779         /*
 780          * Yes, we don't need this put_user() absolutely. However old
 781          * code didn't return the right value. So, app use this value,
 782          * in order to check whether it is EOF.
 783          */
 784         if (put_user(0, &d1->d_reclen))
 785                 return -EFAULT;
 786
 787         return fat_ioctl_readdir(inode, filp, d1, fat_ioctl_filldir,
 788                                  short_only, both);
 789 }
 790
 791 #ifdef CONFIG_COMPAT
 792 #define VFAT_IOCTL_READDIR_BOTH32       _IOR('r', 1, struct compat_dirent[2])
 793 #define VFAT_IOCTL_READDIR_SHORT32      _IOR('r', 2, struct compat_dirent[2])
 794
 795 FAT_IOCTL_FILLDIR_FUNC(fat_compat_ioctl_filldir, compat_dirent)
 796
 797 static long fat_compat_dir_ioctl(struct file *filp, unsigned cmd,
 798                                  unsigned long arg)
 799 {
 800         struct inode *inode = filp->f_path.dentry->d_inode;
 801         struct compat_dirent __user *d1 = compat_ptr(arg);
 802         int short_only, both;
 803
 804         switch (cmd) {
 805         case VFAT_IOCTL_READDIR_SHORT32:
 806                 short_only = 1;
 807                 both = 0;
 808                 break;
 809         case VFAT_IOCTL_READDIR_BOTH32:
 810                 short_only = 0;
 811                 both = 1;
 812                 break;
 813         default:
 814                 return fat_generic_ioctl(filp, cmd, (unsigned long)arg);
 815         }
 816
 817         if (!access_ok(VERIFY_WRITE, d1, sizeof(struct compat_dirent[2])))
 818                 return -EFAULT;
 819         /*
 820          * Yes, we don't need this put_user() absolutely. However old
 821          * code didn't return the right value. So, app use this value,
 822          * in order to check whether it is EOF.
 823          */
 824         if (put_user(0, &d1->d_reclen))
 825                 return -EFAULT;
 826
 827         return fat_ioctl_readdir(inode, filp, d1, fat_compat_ioctl_filldir,
 828                                  short_only, both);
 829 }
 830 #endif /* CONFIG_COMPAT */
 831
 832 const struct file_operations fat_dir_operations = {
 833         .llseek         = generic_file_llseek,
 834         .read           = generic_read_dir,
 835         .readdir        = fat_readdir,
 836         .unlocked_ioctl = fat_dir_ioctl,
 837 #ifdef CONFIG_COMPAT
 838         .compat_ioctl   = fat_compat_dir_ioctl,
 839 #endif
 840         .fsync          = fat_file_fsync,
 841 };
 842
 843 static int fat_get_short_entry(struct inode *dir, loff_t *pos,
 844                                struct buffer_head **bh,
 845                                struct msdos_dir_entry **de)
 846 {
 847         while (fat_get_entry(dir, pos, bh, de) >= 0) {
 848                 /* free entry or long name entry or volume label */
 849                 if (!IS_FREE((*de)->name) && !((*de)->attr & ATTR_VOLUME))
 850                         return 0;
 851         }
 852         return -ENOENT;
 853 }
 854
 855 /*
 856  * The ".." entry can not provide the "struct fat_slot_info" informations
 857  * for inode. So, this function provide the some informations only.
 858  */
 859 int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
 860                          struct msdos_dir_entry **de, loff_t *i_pos)
 861 {
 862         loff_t offset;
 863
 864         offset = 0;
 865         *bh = NULL;
 866         while (fat_get_short_entry(dir, &offset, bh, de) >= 0) {
 867                 if (!strncmp((*de)->name, MSDOS_DOTDOT, MSDOS_NAME)) {
 868                         *i_pos = fat_make_i_pos(dir->i_sb, *bh, *de);
 869                         return 0;
 870                 }
 871         }
 872         return -ENOENT;
 873 }
 874
 875 EXPORT_SYMBOL_GPL(fat_get_dotdot_entry);
 876
 877 /* See if directory is empty */
 878 int fat_dir_empty(struct inode *dir)
 879 {
 880         struct buffer_head *bh;
 881         struct msdos_dir_entry *de;
 882         loff_t cpos;
 883         int result = 0;
 884
 885         bh = NULL;
 886         cpos = 0;
 887         while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
 888                 if (strncmp(de->name, MSDOS_DOT   , MSDOS_NAME) &&
 889                     strncmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
 890                         result = -ENOTEMPTY;
 891                         break;
 892                 }
 893         }
 894         brelse(bh);
 895         return result;
 896 }
 897
 898 EXPORT_SYMBOL_GPL(fat_dir_empty);
 899
 900 /*
 901  * fat_subdirs counts the number of sub-directories of dir. It can be run
 902  * on directories being created.
 903  */
 904 int fat_subdirs(struct inode *dir)
 905 {
 906         struct buffer_head *bh;
 907         struct msdos_dir_entry *de;
 908         loff_t cpos;
 909         int count = 0;
 910
 911         bh = NULL;
 912         cpos = 0;
 913         while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
 914                 if (de->attr & ATTR_DIR)
 915                         count++;
 916         }
 917         brelse(bh);
 918         return count;
 919 }
 920
 921 /*
 922  * Scans a directory for a given file (name points to its formatted name).
 923  * Returns an error code or zero.
 924  */
 925 int fat_scan(struct inode *dir, const unsigned char *name,
 926              struct fat_slot_info *sinfo)
 927 {
 928         struct super_block *sb = dir->i_sb;
 929
 930         sinfo->slot_off = 0;
 931         sinfo->bh = NULL;
 932         while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
 933                                    &sinfo->de) >= 0) {
 934                 if (!strncmp(sinfo->de->name, name, MSDOS_NAME)) {
 935                         sinfo->slot_off -= sizeof(*sinfo->de);
 936                         sinfo->nr_slots = 1;
 937                         sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
 938                         return 0;
 939                 }
 940         }
 941         return -ENOENT;
 942 }
 943
 944 EXPORT_SYMBOL_GPL(fat_scan);
 945
 946 static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots)
 947 {
 948         struct super_block *sb = dir->i_sb;
 949         struct buffer_head *bh;
 950         struct msdos_dir_entry *de, *endp;
 951         int err = 0, orig_slots;
 952
 953         while (nr_slots) {
 954                 bh = NULL;
 955                 if (fat_get_entry(dir, &pos, &bh, &de) < 0) {
 956                         err = -EIO;
 957                         break;
 958                 }
 959
 960                 orig_slots = nr_slots;
 961                 endp = (struct msdos_dir_entry *)(bh->b_data + sb->s_blocksize);
 962                 while (nr_slots && de < endp) {
 963                         de->name[0] = DELETED_FLAG;
 964                         de++;
 965                         nr_slots--;
 966                 }
 967                 mark_buffer_dirty_inode(bh, dir);
 968                 if (IS_DIRSYNC(dir))
 969                         err = sync_dirty_buffer(bh);
 970                 brelse(bh);
 971                 if (err)
 972                         break;
 973
 974                 /* pos is *next* de's position, so this does `- sizeof(de)' */
 975                 pos += ((orig_slots - nr_slots) * sizeof(*de)) - sizeof(*de);
 976         }
 977
 978         return err;
 979 }
 980
 981 int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo)
 982 {
 983         struct super_block *sb = dir->i_sb;
 984         struct msdos_dir_entry *de;
 985         struct buffer_head *bh;
 986         int err = 0, nr_slots;
 987
 988         /*
 989          * First stage: Remove the shortname. By this, the directory
 990          * entry is removed.
 991          */
 992         nr_slots = sinfo->nr_slots;
 993         de = sinfo->de;
 994         sinfo->de = NULL;
 995         bh = sinfo->bh;
 996         sinfo->bh = NULL;
 997         while (nr_slots && de >= (struct msdos_dir_entry *)bh->b_data) {
 998                 de->name[0] = DELETED_FLAG;
 999                 de--;
1000                 nr_slots--;
1001         }
1002         mark_buffer_dirty_inode(bh, dir);
1003         if (IS_DIRSYNC(dir))
1004                 err = sync_dirty_buffer(bh);
1005         brelse(bh);
1006         if (err)
1007                 return err;
1008         dir->i_version++;
1009
1010         if (nr_slots) {
1011                 /*
1012                  * Second stage: remove the remaining longname slots.
1013                  * (This directory entry is already removed, and so return
1014                  * the success)
1015                  */
1016                 err = __fat_remove_entries(dir, sinfo->slot_off, nr_slots);
1017                 if (err) {
1018                         fat_msg(sb, KERN_WARNING,
1019                                "Couldn't remove the long name slots");
1020                 }
1021         }
1022
1023         dir->i_mtime = dir->i_atime = CURRENT_TIME_SEC;
1024         if (IS_DIRSYNC(dir))
1025                 (void)fat_sync_inode(dir);
1026         else
1027                 mark_inode_dirty(dir);
1028
1029         return 0;
1030 }
1031
1032 EXPORT_SYMBOL_GPL(fat_remove_entries);
1033
1034 static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used,
1035                               struct buffer_head **bhs, int nr_bhs)
1036 {
1037         struct super_block *sb = dir->i_sb;
1038         sector_t last_blknr = blknr + MSDOS_SB(sb)->sec_per_clus;
1039         int err, i, n;
1040
1041         /* Zeroing the unused blocks on this cluster */
1042         blknr += nr_used;
1043         n = nr_used;
1044         while (blknr < last_blknr) {
1045                 bhs[n] = sb_getblk(sb, blknr);
1046                 if (!bhs[n]) {
1047                         err = -ENOMEM;
1048                         goto error;
1049                 }
1050                 memset(bhs[n]->b_data, 0, sb->s_blocksize);
1051                 set_buffer_uptodate(bhs[n]);
1052                 mark_buffer_dirty_inode(bhs[n], dir);
1053
1054                 n++;
1055                 blknr++;
1056                 if (n == nr_bhs) {
1057                         if (IS_DIRSYNC(dir)) {
1058                                 err = fat_sync_bhs(bhs, n);
1059                                 if (err)
1060                                         goto error;
1061                         }
1062                         for (i = 0; i < n; i++)
1063                                 brelse(bhs[i]);
1064                         n = 0;
1065                 }
1066         }
1067         if (IS_DIRSYNC(dir)) {
1068                 err = fat_sync_bhs(bhs, n);
1069                 if (err)
1070                         goto error;
1071         }
1072         for (i = 0; i < n; i++)
1073                 brelse(bhs[i]);
1074
1075         return 0;
1076
1077 error:
1078         for (i = 0; i < n; i++)
1079                 bforget(bhs[i]);
1080         return err;
1081 }
1082
1083 int fat_alloc_new_dir(struct inode *dir, struct timespec *ts)
1084 {
1085         struct super_block *sb = dir->i_sb;
1086         struct msdos_sb_info *sbi = MSDOS_SB(sb);
1087         struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1088         struct msdos_dir_entry *de;
1089         sector_t blknr;
1090         __le16 date, time;
1091         u8 time_cs;
1092         int err, cluster;
1093
1094         err = fat_alloc_clusters(dir, &cluster, 1);
1095         if (err)
1096                 goto error;
1097
1098         blknr = fat_clus_to_blknr(sbi, cluster);
1099         bhs[0] = sb_getblk(sb, blknr);
1100         if (!bhs[0]) {
1101                 err = -ENOMEM;
1102                 goto error_free;
1103         }
1104
1105         fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
1106
1107         de = (struct msdos_dir_entry *)bhs[0]->b_data;
1108         /* filling the new directory slots ("." and ".." entries) */
1109         memcpy(de[0].name, MSDOS_DOT, MSDOS_NAME);
1110         memcpy(de[1].name, MSDOS_DOTDOT, MSDOS_NAME);
1111         de->attr = de[1].attr = ATTR_DIR;
1112         de[0].lcase = de[1].lcase = 0;
1113         de[0].time = de[1].time = time;
1114         de[0].date = de[1].date = date;
1115         if (sbi->options.isvfat) {
1116                 /* extra timestamps */
1117                 de[0].ctime = de[1].ctime = time;
1118                 de[0].ctime_cs = de[1].ctime_cs = time_cs;
1119                 de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = date;
1120         } else {
1121                 de[0].ctime = de[1].ctime = 0;
1122                 de[0].ctime_cs = de[1].ctime_cs = 0;
1123                 de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = 0;
1124         }
1125         de[0].start = cpu_to_le16(cluster);
1126         de[0].starthi = cpu_to_le16(cluster >> 16);
1127         de[1].start = cpu_to_le16(MSDOS_I(dir)->i_logstart);
1128         de[1].starthi = cpu_to_le16(MSDOS_I(dir)->i_logstart >> 16);
1129         de[0].size = de[1].size = 0;
1130         memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de));
1131         set_buffer_uptodate(bhs[0]);
1132         mark_buffer_dirty_inode(bhs[0], dir);
1133
1134         err = fat_zeroed_cluster(dir, blknr, 1, bhs, MAX_BUF_PER_PAGE);
1135         if (err)
1136                 goto error_free;
1137
1138         return cluster;
1139
1140 error_free:
1141         fat_free_clusters(dir, cluster);
1142 error:
1143         return err;
1144 }
1145
1146 EXPORT_SYMBOL_GPL(fat_alloc_new_dir);
1147
1148 static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots,
1149                                int *nr_cluster, struct msdos_dir_entry **de,
1150                                struct buffer_head **bh, loff_t *i_pos)
1151 {
1152         struct super_block *sb = dir->i_sb;
1153         struct msdos_sb_info *sbi = MSDOS_SB(sb);
1154         struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1155         sector_t blknr, start_blknr, last_blknr;
1156         unsigned long size, copy;
1157         int err, i, n, offset, cluster[2];
1158
1159         /*
1160          * The minimum cluster size is 512bytes, and maximum entry
1161          * size is 32*slots (672bytes).  So, iff the cluster size is
1162          * 512bytes, we may need two clusters.
1163          */
1164         size = nr_slots * sizeof(struct msdos_dir_entry);
1165         *nr_cluster = (size + (sbi->cluster_size - 1)) >> sbi->cluster_bits;
1166         BUG_ON(*nr_cluster > 2);
1167
1168         err = fat_alloc_clusters(dir, cluster, *nr_cluster);
1169         if (err)
1170                 goto error;
1171
1172         /*
1173          * First stage: Fill the directory entry.  NOTE: This cluster
1174          * is not referenced from any inode yet, so updates order is
1175          * not important.
1176          */
1177         i = n = copy = 0;
1178         do {
1179                 start_blknr = blknr = fat_clus_to_blknr(sbi, cluster[i]);
1180                 last_blknr = start_blknr + sbi->sec_per_clus;
1181                 while (blknr < last_blknr) {
1182                         bhs[n] = sb_getblk(sb, blknr);
1183                         if (!bhs[n]) {
1184                                 err = -ENOMEM;
1185                                 goto error_nomem;
1186                         }
1187
1188                         /* fill the directory entry */
1189                         copy = min(size, sb->s_blocksize);
1190                         memcpy(bhs[n]->b_data, slots, copy);
1191                         slots += copy;
1192                         size -= copy;
1193                         set_buffer_uptodate(bhs[n]);
1194                         mark_buffer_dirty_inode(bhs[n], dir);
1195                         if (!size)
1196                                 break;
1197                         n++;
1198                         blknr++;
1199                 }
1200         } while (++i < *nr_cluster);
1201
1202         memset(bhs[n]->b_data + copy, 0, sb->s_blocksize - copy);
1203         offset = copy - sizeof(struct msdos_dir_entry);
1204         get_bh(bhs[n]);
1205         *bh = bhs[n];
1206         *de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
1207         *i_pos = fat_make_i_pos(sb, *bh, *de);
1208
1209         /* Second stage: clear the rest of cluster, and write outs */
1210         err = fat_zeroed_cluster(dir, start_blknr, ++n, bhs, MAX_BUF_PER_PAGE);
1211         if (err)
1212                 goto error_free;
1213
1214         return cluster[0];
1215
1216 error_free:
1217         brelse(*bh);
1218         *bh = NULL;
1219         n = 0;
1220 error_nomem:
1221         for (i = 0; i < n; i++)
1222                 bforget(bhs[i]);
1223         fat_free_clusters(dir, cluster[0]);
1224 error:
1225         return err;
1226 }
1227
1228 int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
1229                     struct fat_slot_info *sinfo)
1230 {
1231         struct super_block *sb = dir->i_sb;
1232         struct msdos_sb_info *sbi = MSDOS_SB(sb);
1233         struct buffer_head *bh, *prev, *bhs[3]; /* 32*slots (672bytes) */
1234         struct msdos_dir_entry *uninitialized_var(de);
1235         int err, free_slots, i, nr_bhs;
1236         loff_t pos, i_pos;
1237
1238         sinfo->nr_slots = nr_slots;
1239
1240         /* First stage: search free direcotry entries */
1241         free_slots = nr_bhs = 0;
1242         bh = prev = NULL;
1243         pos = 0;
1244         err = -ENOSPC;
1245         while (fat_get_entry(dir, &pos, &bh, &de) > -1) {
1246                 /* check the maximum size of directory */
1247                 if (pos >= FAT_MAX_DIR_SIZE)
1248                         goto error;
1249
1250                 if (IS_FREE(de->name)) {
1251                         if (prev != bh) {
1252                                 get_bh(bh);
1253                                 bhs[nr_bhs] = prev = bh;
1254                                 nr_bhs++;
1255                         }
1256                         free_slots++;
1257                         if (free_slots == nr_slots)
1258                                 goto found;
1259                 } else {
1260                         for (i = 0; i < nr_bhs; i++)
1261                                 brelse(bhs[i]);
1262                         prev = NULL;
1263                         free_slots = nr_bhs = 0;
1264                 }
1265         }
1266         if (dir->i_ino == MSDOS_ROOT_INO) {
1267                 if (sbi->fat_bits != 32)
1268                         goto error;
1269         } else if (MSDOS_I(dir)->i_start == 0) {
1270                 fat_msg(sb, KERN_ERR, "Corrupted directory (i_pos %lld)",
1271                        MSDOS_I(dir)->i_pos);
1272                 err = -EIO;
1273                 goto error;
1274         }
1275
1276 found:
1277         err = 0;
1278         pos -= free_slots * sizeof(*de);
1279         nr_slots -= free_slots;
1280         if (free_slots) {
1281                 /*
1282                  * Second stage: filling the free entries with new entries.
1283                  * NOTE: If this slots has shortname, first, we write
1284                  * the long name slots, then write the short name.
1285                  */
1286                 int size = free_slots * sizeof(*de);
1287                 int offset = pos & (sb->s_blocksize - 1);
1288                 int long_bhs = nr_bhs - (nr_slots == 0);
1289
1290                 /* Fill the long name slots. */
1291                 for (i = 0; i < long_bhs; i++) {
1292                         int copy = min_t(int, sb->s_blocksize - offset, size);
1293                         memcpy(bhs[i]->b_data + offset, slots, copy);
1294                         mark_buffer_dirty_inode(bhs[i], dir);
1295                         offset = 0;
1296                         slots += copy;
1297                         size -= copy;
1298                 }
1299                 if (long_bhs && IS_DIRSYNC(dir))
1300                         err = fat_sync_bhs(bhs, long_bhs);
1301                 if (!err && i < nr_bhs) {
1302                         /* Fill the short name slot. */
1303                         int copy = min_t(int, sb->s_blocksize - offset, size);
1304                         memcpy(bhs[i]->b_data + offset, slots, copy);
1305                         mark_buffer_dirty_inode(bhs[i], dir);
1306                         if (IS_DIRSYNC(dir))
1307                                 err = sync_dirty_buffer(bhs[i]);
1308                 }
1309                 for (i = 0; i < nr_bhs; i++)
1310                         brelse(bhs[i]);
1311                 if (err)
1312                         goto error_remove;
1313         }
1314
1315         if (nr_slots) {
1316                 int cluster, nr_cluster;
1317
1318                 /*
1319                  * Third stage: allocate the cluster for new entries.
1320                  * And initialize the cluster with new entries, then
1321                  * add the cluster to dir.
1322                  */
1323                 cluster = fat_add_new_entries(dir, slots, nr_slots, &nr_cluster,
1324                                               &de, &bh, &i_pos);
1325                 if (cluster < 0) {
1326                         err = cluster;
1327                         goto error_remove;
1328                 }
1329                 err = fat_chain_add(dir, cluster, nr_cluster);
1330                 if (err) {
1331                         fat_free_clusters(dir, cluster);
1332                         goto error_remove;
1333                 }
1334                 if (dir->i_size & (sbi->cluster_size - 1)) {
1335                         fat_fs_error(sb, "Odd directory size");
1336                         dir->i_size = (dir->i_size + sbi->cluster_size - 1)
1337                                 & ~((loff_t)sbi->cluster_size - 1);
1338                 }
1339                 dir->i_size += nr_cluster << sbi->cluster_bits;
1340                 MSDOS_I(dir)->mmu_private += nr_cluster << sbi->cluster_bits;
1341         }
1342         sinfo->slot_off = pos;
1343         sinfo->de = de;
1344         sinfo->bh = bh;
1345         sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
1346
1347         return 0;
1348
1349 error:
1350         brelse(bh);
1351         for (i = 0; i < nr_bhs; i++)
1352                 brelse(bhs[i]);
1353         return err;
1354
1355 error_remove:
1356         brelse(bh);
1357         if (free_slots)
1358                 __fat_remove_entries(dir, pos, free_slots);
1359         return err;
1360 }
1361
1362 EXPORT_SYMBOL_GPL(fat_add_entries);