linux/fs/fat/dir.c
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   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 <linux/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
  38static inline unsigned char fat_tolower(unsigned char c)
  39{
  40        return ((c >= 'A') && (c <= 'Z')) ? c+32 : c;
  41}
  42
  43static inline loff_t fat_make_i_pos(struct super_block *sb,
  44                                    struct buffer_head *bh,
  45                                    struct msdos_dir_entry *de)
  46{
  47        return ((loff_t)bh->b_blocknr << MSDOS_SB(sb)->dir_per_block_bits)
  48                | (de - (struct msdos_dir_entry *)bh->b_data);
  49}
  50
  51static inline void fat_dir_readahead(struct inode *dir, sector_t iblock,
  52                                     sector_t phys)
  53{
  54        struct super_block *sb = dir->i_sb;
  55        struct msdos_sb_info *sbi = MSDOS_SB(sb);
  56        struct buffer_head *bh;
  57        int sec;
  58
  59        /* This is not a first sector of cluster, or sec_per_clus == 1 */
  60        if ((iblock & (sbi->sec_per_clus - 1)) || sbi->sec_per_clus == 1)
  61                return;
  62        /* root dir of FAT12/FAT16 */
  63        if ((sbi->fat_bits != 32) && (dir->i_ino == MSDOS_ROOT_INO))
  64                return;
  65
  66        bh = sb_find_get_block(sb, phys);
  67        if (bh == NULL || !buffer_uptodate(bh)) {
  68                for (sec = 0; sec < sbi->sec_per_clus; sec++)
  69                        sb_breadahead(sb, phys + sec);
  70        }
  71        brelse(bh);
  72}
  73
  74/* Returns the inode number of the directory entry at offset pos. If bh is
  75   non-NULL, it is brelse'd before. Pos is incremented. The buffer header is
  76   returned in bh.
  77   AV. Most often we do it item-by-item. Makes sense to optimize.
  78   AV. OK, there we go: if both bh and de are non-NULL we assume that we just
  79   AV. want the next entry (took one explicit de=NULL in vfat/namei.c).
  80   AV. It's done in fat_get_entry() (inlined), here the slow case lives.
  81   AV. Additionally, when we return -1 (i.e. reached the end of directory)
  82   AV. we make bh NULL.
  83 */
  84static int fat__get_entry(struct inode *dir, loff_t *pos,
  85                          struct buffer_head **bh, struct msdos_dir_entry **de)
  86{
  87        struct super_block *sb = dir->i_sb;
  88        sector_t phys, iblock;
  89        unsigned long mapped_blocks;
  90        int err, offset;
  91
  92next:
  93        if (*bh)
  94                brelse(*bh);
  95
  96        *bh = NULL;
  97        iblock = *pos >> sb->s_blocksize_bits;
  98        err = fat_bmap(dir, iblock, &phys, &mapped_blocks, 0);
  99        if (err || !phys)
 100                return -1;      /* beyond EOF or error */
 101
 102        fat_dir_readahead(dir, iblock, phys);
 103
 104        *bh = sb_bread(sb, phys);
 105        if (*bh == NULL) {
 106                fat_msg_ratelimit(sb, KERN_ERR,
 107                        "Directory bread(block %llu) failed", (llu)phys);
 108                /* skip this block */
 109                *pos = (iblock + 1) << sb->s_blocksize_bits;
 110                goto next;
 111        }
 112
 113        offset = *pos & (sb->s_blocksize - 1);
 114        *pos += sizeof(struct msdos_dir_entry);
 115        *de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
 116
 117        return 0;
 118}
 119
 120static inline int fat_get_entry(struct inode *dir, loff_t *pos,
 121                                struct buffer_head **bh,
 122                                struct msdos_dir_entry **de)
 123{
 124        /* Fast stuff first */
 125        if (*bh && *de &&
 126           (*de - (struct msdos_dir_entry *)(*bh)->b_data) <
 127                                MSDOS_SB(dir->i_sb)->dir_per_block - 1) {
 128                *pos += sizeof(struct msdos_dir_entry);
 129                (*de)++;
 130                return 0;
 131        }
 132        return fat__get_entry(dir, pos, bh, de);
 133}
 134
 135/*
 136 * Convert Unicode 16 to UTF-8, translated Unicode, or ASCII.
 137 * If uni_xlate is enabled and we can't get a 1:1 conversion, use a
 138 * colon as an escape character since it is normally invalid on the vfat
 139 * filesystem. The following four characters are the hexadecimal digits
 140 * of Unicode value. This lets us do a full dump and restore of Unicode
 141 * filenames. We could get into some trouble with long Unicode names,
 142 * but ignore that right now.
 143 * Ahem... Stack smashing in ring 0 isn't fun. Fixed.
 144 */
 145static int uni16_to_x8(struct super_block *sb, unsigned char *ascii,
 146                       const wchar_t *uni, int len, struct nls_table *nls)
 147{
 148        int uni_xlate = MSDOS_SB(sb)->options.unicode_xlate;
 149        const wchar_t *ip;
 150        wchar_t ec;
 151        unsigned char *op;
 152        int charlen;
 153
 154        ip = uni;
 155        op = ascii;
 156
 157        while (*ip && ((len - NLS_MAX_CHARSET_SIZE) > 0)) {
 158                ec = *ip++;
 159                charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE);
 160                if (charlen > 0) {
 161                        op += charlen;
 162                        len -= charlen;
 163                } else {
 164                        if (uni_xlate == 1) {
 165                                *op++ = ':';
 166                                op = hex_byte_pack(op, ec >> 8);
 167                                op = hex_byte_pack(op, ec);
 168                                len -= 5;
 169                        } else {
 170                                *op++ = '?';
 171                                len--;
 172                        }
 173                }
 174        }
 175
 176        if (unlikely(*ip)) {
 177                fat_msg(sb, KERN_WARNING,
 178                        "filename was truncated while converting.");
 179        }
 180
 181        *op = 0;
 182        return op - ascii;
 183}
 184
 185static inline int fat_uni_to_x8(struct super_block *sb, const wchar_t *uni,
 186                                unsigned char *buf, int size)
 187{
 188        struct msdos_sb_info *sbi = MSDOS_SB(sb);
 189        if (sbi->options.utf8)
 190                return utf16s_to_utf8s(uni, FAT_MAX_UNI_CHARS,
 191                                UTF16_HOST_ENDIAN, buf, size);
 192        else
 193                return uni16_to_x8(sb, buf, uni, size, sbi->nls_io);
 194}
 195
 196static inline int
 197fat_short2uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
 198{
 199        int charlen;
 200
 201        charlen = t->char2uni(c, clen, uni);
 202        if (charlen < 0) {
 203                *uni = 0x003f;  /* a question mark */
 204                charlen = 1;
 205        }
 206        return charlen;
 207}
 208
 209static inline int
 210fat_short2lower_uni(struct nls_table *t, unsigned char *c,
 211                    int clen, wchar_t *uni)
 212{
 213        int charlen;
 214        wchar_t wc;
 215
 216        charlen = t->char2uni(c, clen, &wc);
 217        if (charlen < 0) {
 218                *uni = 0x003f;  /* a question mark */
 219                charlen = 1;
 220        } else if (charlen <= 1) {
 221                unsigned char nc = t->charset2lower[*c];
 222
 223                if (!nc)
 224                        nc = *c;
 225
 226                charlen = t->char2uni(&nc, 1, uni);
 227                if (charlen < 0) {
 228                        *uni = 0x003f;  /* a question mark */
 229                        charlen = 1;
 230                }
 231        } else
 232                *uni = wc;
 233
 234        return charlen;
 235}
 236
 237static inline int
 238fat_shortname2uni(struct nls_table *nls, unsigned char *buf, int buf_size,
 239                  wchar_t *uni_buf, unsigned short opt, int lower)
 240{
 241        int len = 0;
 242
 243        if (opt & VFAT_SFN_DISPLAY_LOWER)
 244                len =  fat_short2lower_uni(nls, buf, buf_size, uni_buf);
 245        else if (opt & VFAT_SFN_DISPLAY_WIN95)
 246                len = fat_short2uni(nls, buf, buf_size, uni_buf);
 247        else if (opt & VFAT_SFN_DISPLAY_WINNT) {
 248                if (lower)
 249                        len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);
 250                else
 251                        len = fat_short2uni(nls, buf, buf_size, uni_buf);
 252        } else
 253                len = fat_short2uni(nls, buf, buf_size, uni_buf);
 254
 255        return len;
 256}
 257
 258static inline int fat_name_match(struct msdos_sb_info *sbi,
 259                                 const unsigned char *a, int a_len,
 260                                 const unsigned char *b, int b_len)
 261{
 262        if (a_len != b_len)
 263                return 0;
 264
 265        if (sbi->options.name_check != 's')
 266                return !nls_strnicmp(sbi->nls_io, a, b, a_len);
 267        else
 268                return !memcmp(a, b, a_len);
 269}
 270
 271enum { PARSE_INVALID = 1, PARSE_NOT_LONGNAME, PARSE_EOF, };
 272
 273/**
 274 * fat_parse_long - Parse extended directory entry.
 275 *
 276 * This function returns zero on success, negative value on error, or one of
 277 * the following:
 278 *
 279 * %PARSE_INVALID - Directory entry is invalid.
 280 * %PARSE_NOT_LONGNAME - Directory entry does not contain longname.
 281 * %PARSE_EOF - Directory has no more entries.
 282 */
 283static int fat_parse_long(struct inode *dir, loff_t *pos,
 284                          struct buffer_head **bh, struct msdos_dir_entry **de,
 285                          wchar_t **unicode, unsigned char *nr_slots)
 286{
 287        struct msdos_dir_slot *ds;
 288        unsigned char id, slot, slots, alias_checksum;
 289
 290        if (!*unicode) {
 291                *unicode = __getname();
 292                if (!*unicode) {
 293                        brelse(*bh);
 294                        return -ENOMEM;
 295                }
 296        }
 297parse_long:
 298        slots = 0;
 299        ds = (struct msdos_dir_slot *)*de;
 300        id = ds->id;
 301        if (!(id & 0x40))
 302                return PARSE_INVALID;
 303        slots = id & ~0x40;
 304        if (slots > 20 || !slots)       /* ceil(256 * 2 / 26) */
 305                return PARSE_INVALID;
 306        *nr_slots = slots;
 307        alias_checksum = ds->alias_checksum;
 308
 309        slot = slots;
 310        while (1) {
 311                int offset;
 312
 313                slot--;
 314                offset = slot * 13;
 315                fat16_towchar(*unicode + offset, ds->name0_4, 5);
 316                fat16_towchar(*unicode + offset + 5, ds->name5_10, 6);
 317                fat16_towchar(*unicode + offset + 11, ds->name11_12, 2);
 318
 319                if (ds->id & 0x40)
 320                        (*unicode)[offset + 13] = 0;
 321                if (fat_get_entry(dir, pos, bh, de) < 0)
 322                        return PARSE_EOF;
 323                if (slot == 0)
 324                        break;
 325                ds = (struct msdos_dir_slot *)*de;
 326                if (ds->attr != ATTR_EXT)
 327                        return PARSE_NOT_LONGNAME;
 328                if ((ds->id & ~0x40) != slot)
 329                        goto parse_long;
 330                if (ds->alias_checksum != alias_checksum)
 331                        goto parse_long;
 332        }
 333        if ((*de)->name[0] == DELETED_FLAG)
 334                return PARSE_INVALID;
 335        if ((*de)->attr == ATTR_EXT)
 336                goto parse_long;
 337        if (IS_FREE((*de)->name) || ((*de)->attr & ATTR_VOLUME))
 338                return PARSE_INVALID;
 339        if (fat_checksum((*de)->name) != alias_checksum)
 340                *nr_slots = 0;
 341
 342        return 0;
 343}
 344
 345/**
 346 * fat_parse_short - Parse MS-DOS (short) directory entry.
 347 * @sb:         superblock
 348 * @de:         directory entry to parse
 349 * @name:       FAT_MAX_SHORT_SIZE array in which to place extracted name
 350 * @dot_hidden: Nonzero == prepend '.' to names with ATTR_HIDDEN
 351 *
 352 * Returns the number of characters extracted into 'name'.
 353 */
 354static int fat_parse_short(struct super_block *sb,
 355                           const struct msdos_dir_entry *de,
 356                           unsigned char *name, int dot_hidden)
 357{
 358        const struct msdos_sb_info *sbi = MSDOS_SB(sb);
 359        int isvfat = sbi->options.isvfat;
 360        int nocase = sbi->options.nocase;
 361        unsigned short opt_shortname = sbi->options.shortname;
 362        struct nls_table *nls_disk = sbi->nls_disk;
 363        wchar_t uni_name[14];
 364        unsigned char c, work[MSDOS_NAME];
 365        unsigned char *ptname = name;
 366        int chi, chl, i, j, k;
 367        int dotoffset = 0;
 368        int name_len = 0, uni_len = 0;
 369
 370        if (!isvfat && dot_hidden && (de->attr & ATTR_HIDDEN)) {
 371                *ptname++ = '.';
 372                dotoffset = 1;
 373        }
 374
 375        memcpy(work, de->name, sizeof(work));
 376        /* see namei.c, msdos_format_name */
 377        if (work[0] == 0x05)
 378                work[0] = 0xE5;
 379
 380        /* Filename */
 381        for (i = 0, j = 0; i < 8;) {
 382                c = work[i];
 383                if (!c)
 384                        break;
 385                chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
 386                                        &uni_name[j++], opt_shortname,
 387                                        de->lcase & CASE_LOWER_BASE);
 388                if (chl <= 1) {
 389                        if (!isvfat)
 390                                ptname[i] = nocase ? c : fat_tolower(c);
 391                        i++;
 392                        if (c != ' ') {
 393                                name_len = i;
 394                                uni_len  = j;
 395                        }
 396                } else {
 397                        uni_len = j;
 398                        if (isvfat)
 399                                i += min(chl, 8-i);
 400                        else {
 401                                for (chi = 0; chi < chl && i < 8; chi++, i++)
 402                                        ptname[i] = work[i];
 403                        }
 404                        if (chl)
 405                                name_len = i;
 406                }
 407        }
 408
 409        i = name_len;
 410        j = uni_len;
 411        fat_short2uni(nls_disk, ".", 1, &uni_name[j++]);
 412        if (!isvfat)
 413                ptname[i] = '.';
 414        i++;
 415
 416        /* Extension */
 417        for (k = 8; k < MSDOS_NAME;) {
 418                c = work[k];
 419                if (!c)
 420                        break;
 421                chl = fat_shortname2uni(nls_disk, &work[k], MSDOS_NAME - k,
 422                                        &uni_name[j++], opt_shortname,
 423                                        de->lcase & CASE_LOWER_EXT);
 424                if (chl <= 1) {
 425                        k++;
 426                        if (!isvfat)
 427                                ptname[i] = nocase ? c : fat_tolower(c);
 428                        i++;
 429                        if (c != ' ') {
 430                                name_len = i;
 431                                uni_len  = j;
 432                        }
 433                } else {
 434                        uni_len = j;
 435                        if (isvfat) {
 436                                int offset = min(chl, MSDOS_NAME-k);
 437                                k += offset;
 438                                i += offset;
 439                        } else {
 440                                for (chi = 0; chi < chl && k < MSDOS_NAME;
 441                                     chi++, i++, k++) {
 442                                                ptname[i] = work[k];
 443                                }
 444                        }
 445                        if (chl)
 446                                name_len = i;
 447                }
 448        }
 449
 450        if (name_len > 0) {
 451                name_len += dotoffset;
 452
 453                if (sbi->options.isvfat) {
 454                        uni_name[uni_len] = 0x0000;
 455                        name_len = fat_uni_to_x8(sb, uni_name, name,
 456                                                 FAT_MAX_SHORT_SIZE);
 457                }
 458        }
 459
 460        return name_len;
 461}
 462
 463/*
 464 * Return values: negative -> error, 0 -> not found, positive -> found,
 465 * value is the total amount of slots, including the shortname entry.
 466 */
 467int fat_search_long(struct inode *inode, const unsigned char *name,
 468                    int name_len, struct fat_slot_info *sinfo)
 469{
 470        struct super_block *sb = inode->i_sb;
 471        struct msdos_sb_info *sbi = MSDOS_SB(sb);
 472        struct buffer_head *bh = NULL;
 473        struct msdos_dir_entry *de;
 474        unsigned char nr_slots;
 475        wchar_t *unicode = NULL;
 476        unsigned char bufname[FAT_MAX_SHORT_SIZE];
 477        loff_t cpos = 0;
 478        int err, len;
 479
 480        err = -ENOENT;
 481        while (1) {
 482                if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
 483                        goto end_of_dir;
 484parse_record:
 485                nr_slots = 0;
 486                if (de->name[0] == DELETED_FLAG)
 487                        continue;
 488                if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
 489                        continue;
 490                if (de->attr != ATTR_EXT && IS_FREE(de->name))
 491                        continue;
 492                if (de->attr == ATTR_EXT) {
 493                        int status = fat_parse_long(inode, &cpos, &bh, &de,
 494                                                    &unicode, &nr_slots);
 495                        if (status < 0) {
 496                                err = status;
 497                                goto end_of_dir;
 498                        } else if (status == PARSE_INVALID)
 499                                continue;
 500                        else if (status == PARSE_NOT_LONGNAME)
 501                                goto parse_record;
 502                        else if (status == PARSE_EOF)
 503                                goto end_of_dir;
 504                }
 505
 506                /* Never prepend '.' to hidden files here.
 507                 * That is done only for msdos mounts (and only when
 508                 * 'dotsOK=yes'); if we are executing here, it is in the
 509                 * context of a vfat mount.
 510                 */
 511                len = fat_parse_short(sb, de, bufname, 0);
 512                if (len == 0)
 513                        continue;
 514
 515                /* Compare shortname */
 516                if (fat_name_match(sbi, name, name_len, bufname, len))
 517                        goto found;
 518
 519                if (nr_slots) {
 520                        void *longname = unicode + FAT_MAX_UNI_CHARS;
 521                        int size = PATH_MAX - FAT_MAX_UNI_SIZE;
 522
 523                        /* Compare longname */
 524                        len = fat_uni_to_x8(sb, unicode, longname, size);
 525                        if (fat_name_match(sbi, name, name_len, longname, len))
 526                                goto found;
 527                }
 528        }
 529
 530found:
 531        nr_slots++;     /* include the de */
 532        sinfo->slot_off = cpos - nr_slots * sizeof(*de);
 533        sinfo->nr_slots = nr_slots;
 534        sinfo->de = de;
 535        sinfo->bh = bh;
 536        sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
 537        err = 0;
 538end_of_dir:
 539        if (unicode)
 540                __putname(unicode);
 541
 542        return err;
 543}
 544EXPORT_SYMBOL_GPL(fat_search_long);
 545
 546struct fat_ioctl_filldir_callback {
 547        void __user *dirent;
 548        int result;
 549        /* for dir ioctl */
 550        const char *longname;
 551        int long_len;
 552        const char *shortname;
 553        int short_len;
 554};
 555
 556static int __fat_readdir(struct inode *inode, struct file *filp, void *dirent,
 557                         filldir_t filldir, int short_only, int both)
 558{
 559        struct super_block *sb = inode->i_sb;
 560        struct msdos_sb_info *sbi = MSDOS_SB(sb);
 561        struct buffer_head *bh;
 562        struct msdos_dir_entry *de;
 563        unsigned char nr_slots;
 564        wchar_t *unicode = NULL;
 565        unsigned char bufname[FAT_MAX_SHORT_SIZE];
 566        int isvfat = sbi->options.isvfat;
 567        const char *fill_name = NULL;
 568        unsigned long inum;
 569        unsigned long lpos, dummy, *furrfu = &lpos;
 570        loff_t cpos;
 571        int short_len = 0, fill_len = 0;
 572        int ret = 0;
 573
 574        mutex_lock(&sbi->s_lock);
 575
 576        cpos = filp->f_pos;
 577        /* Fake . and .. for the root directory. */
 578        if (inode->i_ino == MSDOS_ROOT_INO) {
 579                while (cpos < 2) {
 580                        if (filldir(dirent, "..", cpos+1, cpos,
 581                                    MSDOS_ROOT_INO, DT_DIR) < 0)
 582                                goto out;
 583                        cpos++;
 584                        filp->f_pos++;
 585                }
 586                if (cpos == 2) {
 587                        dummy = 2;
 588                        furrfu = &dummy;
 589                        cpos = 0;
 590                }
 591        }
 592        if (cpos & (sizeof(struct msdos_dir_entry) - 1)) {
 593                ret = -ENOENT;
 594                goto out;
 595        }
 596
 597        bh = NULL;
 598get_new:
 599        if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
 600                goto end_of_dir;
 601parse_record:
 602        nr_slots = 0;
 603        /*
 604         * Check for long filename entry, but if short_only, we don't
 605         * need to parse long filename.
 606         */
 607        if (isvfat && !short_only) {
 608                if (de->name[0] == DELETED_FLAG)
 609                        goto record_end;
 610                if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
 611                        goto record_end;
 612                if (de->attr != ATTR_EXT && IS_FREE(de->name))
 613                        goto record_end;
 614        } else {
 615                if ((de->attr & ATTR_VOLUME) || IS_FREE(de->name))
 616                        goto record_end;
 617        }
 618
 619        if (isvfat && de->attr == ATTR_EXT) {
 620                int status = fat_parse_long(inode, &cpos, &bh, &de,
 621                                            &unicode, &nr_slots);
 622                if (status < 0) {
 623                        filp->f_pos = cpos;
 624                        ret = status;
 625                        goto out;
 626                } else if (status == PARSE_INVALID)
 627                        goto record_end;
 628                else if (status == PARSE_NOT_LONGNAME)
 629                        goto parse_record;
 630                else if (status == PARSE_EOF)
 631                        goto end_of_dir;
 632
 633                if (nr_slots) {
 634                        void *longname = unicode + FAT_MAX_UNI_CHARS;
 635                        int size = PATH_MAX - FAT_MAX_UNI_SIZE;
 636                        int len = fat_uni_to_x8(sb, unicode, longname, size);
 637
 638                        fill_name = longname;
 639                        fill_len = len;
 640                        /* !both && !short_only, so we don't need shortname. */
 641                        if (!both)
 642                                goto start_filldir;
 643                }
 644        }
 645
 646        short_len = fat_parse_short(sb, de, bufname, sbi->options.dotsOK);
 647        if (short_len == 0)
 648                goto record_end;
 649
 650        if (nr_slots) {
 651                /* hack for fat_ioctl_filldir() */
 652                struct fat_ioctl_filldir_callback *p = dirent;
 653
 654                p->longname = fill_name;
 655                p->long_len = fill_len;
 656                p->shortname = bufname;
 657                p->short_len = short_len;
 658                fill_name = NULL;
 659                fill_len = 0;
 660        } else {
 661                fill_name = bufname;
 662                fill_len = short_len;
 663        }
 664
 665start_filldir:
 666        lpos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry);
 667        if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME))
 668                inum = inode->i_ino;
 669        else if (!memcmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
 670                inum = parent_ino(filp->f_path.dentry);
 671        } else {
 672                loff_t i_pos = fat_make_i_pos(sb, bh, de);
 673                struct inode *tmp = fat_iget(sb, i_pos);
 674                if (tmp) {
 675                        inum = tmp->i_ino;
 676                        iput(tmp);
 677                } else
 678                        inum = iunique(sb, MSDOS_ROOT_INO);
 679        }
 680
 681        if (filldir(dirent, fill_name, fill_len, *furrfu, inum,
 682                    (de->attr & ATTR_DIR) ? DT_DIR : DT_REG) < 0)
 683                goto fill_failed;
 684
 685record_end:
 686        furrfu = &lpos;
 687        filp->f_pos = cpos;
 688        goto get_new;
 689end_of_dir:
 690        filp->f_pos = cpos;
 691fill_failed:
 692        brelse(bh);
 693        if (unicode)
 694                __putname(unicode);
 695out:
 696        mutex_unlock(&sbi->s_lock);
 697        return ret;
 698}
 699
 700static int fat_readdir(struct file *filp, void *dirent, filldir_t filldir)
 701{
 702        struct inode *inode = filp->f_path.dentry->d_inode;
 703        return __fat_readdir(inode, filp, dirent, filldir, 0, 0);
 704}
 705
 706#define FAT_IOCTL_FILLDIR_FUNC(func, dirent_type)                          \
 707static int func(void *__buf, const char *name, int name_len,               \
 708                             loff_t offset, u64 ino, unsigned int d_type)  \
 709{                                                                          \
 710        struct fat_ioctl_filldir_callback *buf = __buf;                    \
 711        struct dirent_type __user *d1 = buf->dirent;                       \
 712        struct dirent_type __user *d2 = d1 + 1;                            \
 713                                                                           \
 714        if (buf->result)                                                   \
 715                return -EINVAL;                                            \
 716        buf->result++;                                                     \
 717                                                                           \
 718        if (name != NULL) {                                                \
 719                /* dirent has only short name */                           \
 720                if (name_len >= sizeof(d1->d_name))                        \
 721                        name_len = sizeof(d1->d_name) - 1;                 \
 722                                                                           \
 723                if (put_user(0, d2->d_name)                     ||         \
 724                    put_user(0, &d2->d_reclen)                  ||         \
 725                    copy_to_user(d1->d_name, name, name_len)    ||         \
 726                    put_user(0, d1->d_name + name_len)          ||         \
 727                    put_user(name_len, &d1->d_reclen))                     \
 728                        goto efault;                                       \
 729        } else {                                                           \
 730                /* dirent has short and long name */                       \
 731                const char *longname = buf->longname;                      \
 732                int long_len = buf->long_len;                              \
 733                const char *shortname = buf->shortname;                    \
 734                int short_len = buf->short_len;                            \
 735                                                                           \
 736                if (long_len >= sizeof(d1->d_name))                        \
 737                        long_len = sizeof(d1->d_name) - 1;                 \
 738                if (short_len >= sizeof(d1->d_name))                       \
 739                        short_len = sizeof(d1->d_name) - 1;                \
 740                                                                           \
 741                if (copy_to_user(d2->d_name, longname, long_len)        || \
 742                    put_user(0, d2->d_name + long_len)                  || \
 743                    put_user(long_len, &d2->d_reclen)                   || \
 744                    put_user(ino, &d2->d_ino)                           || \
 745                    put_user(offset, &d2->d_off)                        || \
 746                    copy_to_user(d1->d_name, shortname, short_len)      || \
 747                    put_user(0, d1->d_name + short_len)                 || \
 748                    put_user(short_len, &d1->d_reclen))                    \
 749                        goto efault;                                       \
 750        }                                                                  \
 751        return 0;                                                          \
 752efault:                                                                    \
 753        buf->result = -EFAULT;                                             \
 754        return -EFAULT;                                                    \
 755}
 756
 757FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent)
 758
 759static int fat_ioctl_readdir(struct inode *inode, struct file *filp,
 760                             void __user *dirent, filldir_t filldir,
 761                             int short_only, int both)
 762{
 763        struct fat_ioctl_filldir_callback buf;
 764        int ret;
 765
 766        buf.dirent = dirent;
 767        buf.result = 0;
 768        mutex_lock(&inode->i_mutex);
 769        ret = -ENOENT;
 770        if (!IS_DEADDIR(inode)) {
 771                ret = __fat_readdir(inode, filp, &buf, filldir,
 772                                    short_only, both);
 773        }
 774        mutex_unlock(&inode->i_mutex);
 775        if (ret >= 0)
 776                ret = buf.result;
 777        return ret;
 778}
 779
 780static long fat_dir_ioctl(struct file *filp, unsigned int cmd,
 781                          unsigned long arg)
 782{
 783        struct inode *inode = filp->f_path.dentry->d_inode;
 784        struct __fat_dirent __user *d1 = (struct __fat_dirent __user *)arg;
 785        int short_only, both;
 786
 787        switch (cmd) {
 788        case VFAT_IOCTL_READDIR_SHORT:
 789                short_only = 1;
 790                both = 0;
 791                break;
 792        case VFAT_IOCTL_READDIR_BOTH:
 793                short_only = 0;
 794                both = 1;
 795                break;
 796        default:
 797                return fat_generic_ioctl(filp, cmd, arg);
 798        }
 799
 800        if (!access_ok(VERIFY_WRITE, d1, sizeof(struct __fat_dirent[2])))
 801                return -EFAULT;
 802        /*
 803         * Yes, we don't need this put_user() absolutely. However old
 804         * code didn't return the right value. So, app use this value,
 805         * in order to check whether it is EOF.
 806         */
 807        if (put_user(0, &d1->d_reclen))
 808                return -EFAULT;
 809
 810        return fat_ioctl_readdir(inode, filp, d1, fat_ioctl_filldir,
 811                                 short_only, both);
 812}
 813
 814#ifdef CONFIG_COMPAT
 815#define VFAT_IOCTL_READDIR_BOTH32       _IOR('r', 1, struct compat_dirent[2])
 816#define VFAT_IOCTL_READDIR_SHORT32      _IOR('r', 2, struct compat_dirent[2])
 817
 818FAT_IOCTL_FILLDIR_FUNC(fat_compat_ioctl_filldir, compat_dirent)
 819
 820static long fat_compat_dir_ioctl(struct file *filp, unsigned cmd,
 821                                 unsigned long arg)
 822{
 823        struct inode *inode = filp->f_path.dentry->d_inode;
 824        struct compat_dirent __user *d1 = compat_ptr(arg);
 825        int short_only, both;
 826
 827        switch (cmd) {
 828        case VFAT_IOCTL_READDIR_SHORT32:
 829                short_only = 1;
 830                both = 0;
 831                break;
 832        case VFAT_IOCTL_READDIR_BOTH32:
 833                short_only = 0;
 834                both = 1;
 835                break;
 836        default:
 837                return fat_generic_ioctl(filp, cmd, (unsigned long)arg);
 838        }
 839
 840        if (!access_ok(VERIFY_WRITE, d1, sizeof(struct compat_dirent[2])))
 841                return -EFAULT;
 842        /*
 843         * Yes, we don't need this put_user() absolutely. However old
 844         * code didn't return the right value. So, app use this value,
 845         * in order to check whether it is EOF.
 846         */
 847        if (put_user(0, &d1->d_reclen))
 848                return -EFAULT;
 849
 850        return fat_ioctl_readdir(inode, filp, d1, fat_compat_ioctl_filldir,
 851                                 short_only, both);
 852}
 853#endif /* CONFIG_COMPAT */
 854
 855const struct file_operations fat_dir_operations = {
 856        .llseek         = generic_file_llseek,
 857        .read           = generic_read_dir,
 858        .readdir        = fat_readdir,
 859        .unlocked_ioctl = fat_dir_ioctl,
 860#ifdef CONFIG_COMPAT
 861        .compat_ioctl   = fat_compat_dir_ioctl,
 862#endif
 863        .fsync          = fat_file_fsync,
 864};
 865
 866static int fat_get_short_entry(struct inode *dir, loff_t *pos,
 867                               struct buffer_head **bh,
 868                               struct msdos_dir_entry **de)
 869{
 870        while (fat_get_entry(dir, pos, bh, de) >= 0) {
 871                /* free entry or long name entry or volume label */
 872                if (!IS_FREE((*de)->name) && !((*de)->attr & ATTR_VOLUME))
 873                        return 0;
 874        }
 875        return -ENOENT;
 876}
 877
 878/*
 879 * The ".." entry can not provide the "struct fat_slot_info" information
 880 * for inode, nor a usable i_pos. So, this function provides some information
 881 * only.
 882 *
 883 * Since this function walks through the on-disk inodes within a directory,
 884 * callers are responsible for taking any locks necessary to prevent the
 885 * directory from changing.
 886 */
 887int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
 888                         struct msdos_dir_entry **de)
 889{
 890        loff_t offset = 0;
 891
 892        *de = NULL;
 893        while (fat_get_short_entry(dir, &offset, bh, de) >= 0) {
 894                if (!strncmp((*de)->name, MSDOS_DOTDOT, MSDOS_NAME))
 895                        return 0;
 896        }
 897        return -ENOENT;
 898}
 899EXPORT_SYMBOL_GPL(fat_get_dotdot_entry);
 900
 901/* See if directory is empty */
 902int fat_dir_empty(struct inode *dir)
 903{
 904        struct buffer_head *bh;
 905        struct msdos_dir_entry *de;
 906        loff_t cpos;
 907        int result = 0;
 908
 909        bh = NULL;
 910        cpos = 0;
 911        while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
 912                if (strncmp(de->name, MSDOS_DOT   , MSDOS_NAME) &&
 913                    strncmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
 914                        result = -ENOTEMPTY;
 915                        break;
 916                }
 917        }
 918        brelse(bh);
 919        return result;
 920}
 921EXPORT_SYMBOL_GPL(fat_dir_empty);
 922
 923/*
 924 * fat_subdirs counts the number of sub-directories of dir. It can be run
 925 * on directories being created.
 926 */
 927int fat_subdirs(struct inode *dir)
 928{
 929        struct buffer_head *bh;
 930        struct msdos_dir_entry *de;
 931        loff_t cpos;
 932        int count = 0;
 933
 934        bh = NULL;
 935        cpos = 0;
 936        while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
 937                if (de->attr & ATTR_DIR)
 938                        count++;
 939        }
 940        brelse(bh);
 941        return count;
 942}
 943
 944/*
 945 * Scans a directory for a given file (name points to its formatted name).
 946 * Returns an error code or zero.
 947 */
 948int fat_scan(struct inode *dir, const unsigned char *name,
 949             struct fat_slot_info *sinfo)
 950{
 951        struct super_block *sb = dir->i_sb;
 952
 953        sinfo->slot_off = 0;
 954        sinfo->bh = NULL;
 955        while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
 956                                   &sinfo->de) >= 0) {
 957                if (!strncmp(sinfo->de->name, name, MSDOS_NAME)) {
 958                        sinfo->slot_off -= sizeof(*sinfo->de);
 959                        sinfo->nr_slots = 1;
 960                        sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
 961                        return 0;
 962                }
 963        }
 964        return -ENOENT;
 965}
 966EXPORT_SYMBOL_GPL(fat_scan);
 967
 968static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots)
 969{
 970        struct super_block *sb = dir->i_sb;
 971        struct buffer_head *bh;
 972        struct msdos_dir_entry *de, *endp;
 973        int err = 0, orig_slots;
 974
 975        while (nr_slots) {
 976                bh = NULL;
 977                if (fat_get_entry(dir, &pos, &bh, &de) < 0) {
 978                        err = -EIO;
 979                        break;
 980                }
 981
 982                orig_slots = nr_slots;
 983                endp = (struct msdos_dir_entry *)(bh->b_data + sb->s_blocksize);
 984                while (nr_slots && de < endp) {
 985                        de->name[0] = DELETED_FLAG;
 986                        de++;
 987                        nr_slots--;
 988                }
 989                mark_buffer_dirty_inode(bh, dir);
 990                if (IS_DIRSYNC(dir))
 991                        err = sync_dirty_buffer(bh);
 992                brelse(bh);
 993                if (err)
 994                        break;
 995
 996                /* pos is *next* de's position, so this does `- sizeof(de)' */
 997                pos += ((orig_slots - nr_slots) * sizeof(*de)) - sizeof(*de);
 998        }
 999
1000        return err;
1001}
1002
1003int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo)
1004{
1005        struct super_block *sb = dir->i_sb;
1006        struct msdos_dir_entry *de;
1007        struct buffer_head *bh;
1008        int err = 0, nr_slots;
1009
1010        /*
1011         * First stage: Remove the shortname. By this, the directory
1012         * entry is removed.
1013         */
1014        nr_slots = sinfo->nr_slots;
1015        de = sinfo->de;
1016        sinfo->de = NULL;
1017        bh = sinfo->bh;
1018        sinfo->bh = NULL;
1019        while (nr_slots && de >= (struct msdos_dir_entry *)bh->b_data) {
1020                de->name[0] = DELETED_FLAG;
1021                de--;
1022                nr_slots--;
1023        }
1024        mark_buffer_dirty_inode(bh, dir);
1025        if (IS_DIRSYNC(dir))
1026                err = sync_dirty_buffer(bh);
1027        brelse(bh);
1028        if (err)
1029                return err;
1030        dir->i_version++;
1031
1032        if (nr_slots) {
1033                /*
1034                 * Second stage: remove the remaining longname slots.
1035                 * (This directory entry is already removed, and so return
1036                 * the success)
1037                 */
1038                err = __fat_remove_entries(dir, sinfo->slot_off, nr_slots);
1039                if (err) {
1040                        fat_msg(sb, KERN_WARNING,
1041                               "Couldn't remove the long name slots");
1042                }
1043        }
1044
1045        dir->i_mtime = dir->i_atime = CURRENT_TIME_SEC;
1046        if (IS_DIRSYNC(dir))
1047                (void)fat_sync_inode(dir);
1048        else
1049                mark_inode_dirty(dir);
1050
1051        return 0;
1052}
1053EXPORT_SYMBOL_GPL(fat_remove_entries);
1054
1055static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used,
1056                              struct buffer_head **bhs, int nr_bhs)
1057{
1058        struct super_block *sb = dir->i_sb;
1059        sector_t last_blknr = blknr + MSDOS_SB(sb)->sec_per_clus;
1060        int err, i, n;
1061
1062        /* Zeroing the unused blocks on this cluster */
1063        blknr += nr_used;
1064        n = nr_used;
1065        while (blknr < last_blknr) {
1066                bhs[n] = sb_getblk(sb, blknr);
1067                if (!bhs[n]) {
1068                        err = -ENOMEM;
1069                        goto error;
1070                }
1071                memset(bhs[n]->b_data, 0, sb->s_blocksize);
1072                set_buffer_uptodate(bhs[n]);
1073                mark_buffer_dirty_inode(bhs[n], dir);
1074
1075                n++;
1076                blknr++;
1077                if (n == nr_bhs) {
1078                        if (IS_DIRSYNC(dir)) {
1079                                err = fat_sync_bhs(bhs, n);
1080                                if (err)
1081                                        goto error;
1082                        }
1083                        for (i = 0; i < n; i++)
1084                                brelse(bhs[i]);
1085                        n = 0;
1086                }
1087        }
1088        if (IS_DIRSYNC(dir)) {
1089                err = fat_sync_bhs(bhs, n);
1090                if (err)
1091                        goto error;
1092        }
1093        for (i = 0; i < n; i++)
1094                brelse(bhs[i]);
1095
1096        return 0;
1097
1098error:
1099        for (i = 0; i < n; i++)
1100                bforget(bhs[i]);
1101        return err;
1102}
1103
1104int fat_alloc_new_dir(struct inode *dir, struct timespec *ts)
1105{
1106        struct super_block *sb = dir->i_sb;
1107        struct msdos_sb_info *sbi = MSDOS_SB(sb);
1108        struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1109        struct msdos_dir_entry *de;
1110        sector_t blknr;
1111        __le16 date, time;
1112        u8 time_cs;
1113        int err, cluster;
1114
1115        err = fat_alloc_clusters(dir, &cluster, 1);
1116        if (err)
1117                goto error;
1118
1119        blknr = fat_clus_to_blknr(sbi, cluster);
1120        bhs[0] = sb_getblk(sb, blknr);
1121        if (!bhs[0]) {
1122                err = -ENOMEM;
1123                goto error_free;
1124        }
1125
1126        fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
1127
1128        de = (struct msdos_dir_entry *)bhs[0]->b_data;
1129        /* filling the new directory slots ("." and ".." entries) */
1130        memcpy(de[0].name, MSDOS_DOT, MSDOS_NAME);
1131        memcpy(de[1].name, MSDOS_DOTDOT, MSDOS_NAME);
1132        de->attr = de[1].attr = ATTR_DIR;
1133        de[0].lcase = de[1].lcase = 0;
1134        de[0].time = de[1].time = time;
1135        de[0].date = de[1].date = date;
1136        if (sbi->options.isvfat) {
1137                /* extra timestamps */
1138                de[0].ctime = de[1].ctime = time;
1139                de[0].ctime_cs = de[1].ctime_cs = time_cs;
1140                de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = date;
1141        } else {
1142                de[0].ctime = de[1].ctime = 0;
1143                de[0].ctime_cs = de[1].ctime_cs = 0;
1144                de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = 0;
1145        }
1146        fat_set_start(&de[0], cluster);
1147        fat_set_start(&de[1], MSDOS_I(dir)->i_logstart);
1148        de[0].size = de[1].size = 0;
1149        memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de));
1150        set_buffer_uptodate(bhs[0]);
1151        mark_buffer_dirty_inode(bhs[0], dir);
1152
1153        err = fat_zeroed_cluster(dir, blknr, 1, bhs, MAX_BUF_PER_PAGE);
1154        if (err)
1155                goto error_free;
1156
1157        return cluster;
1158
1159error_free:
1160        fat_free_clusters(dir, cluster);
1161error:
1162        return err;
1163}
1164EXPORT_SYMBOL_GPL(fat_alloc_new_dir);
1165
1166static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots,
1167                               int *nr_cluster, struct msdos_dir_entry **de,
1168                               struct buffer_head **bh, loff_t *i_pos)
1169{
1170        struct super_block *sb = dir->i_sb;
1171        struct msdos_sb_info *sbi = MSDOS_SB(sb);
1172        struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1173        sector_t blknr, start_blknr, last_blknr;
1174        unsigned long size, copy;
1175        int err, i, n, offset, cluster[2];
1176
1177        /*
1178         * The minimum cluster size is 512bytes, and maximum entry
1179         * size is 32*slots (672bytes).  So, iff the cluster size is
1180         * 512bytes, we may need two clusters.
1181         */
1182        size = nr_slots * sizeof(struct msdos_dir_entry);
1183        *nr_cluster = (size + (sbi->cluster_size - 1)) >> sbi->cluster_bits;
1184        BUG_ON(*nr_cluster > 2);
1185
1186        err = fat_alloc_clusters(dir, cluster, *nr_cluster);
1187        if (err)
1188                goto error;
1189
1190        /*
1191         * First stage: Fill the directory entry.  NOTE: This cluster
1192         * is not referenced from any inode yet, so updates order is
1193         * not important.
1194         */
1195        i = n = copy = 0;
1196        do {
1197                start_blknr = blknr = fat_clus_to_blknr(sbi, cluster[i]);
1198                last_blknr = start_blknr + sbi->sec_per_clus;
1199                while (blknr < last_blknr) {
1200                        bhs[n] = sb_getblk(sb, blknr);
1201                        if (!bhs[n]) {
1202                                err = -ENOMEM;
1203                                goto error_nomem;
1204                        }
1205
1206                        /* fill the directory entry */
1207                        copy = min(size, sb->s_blocksize);
1208                        memcpy(bhs[n]->b_data, slots, copy);
1209                        slots += copy;
1210                        size -= copy;
1211                        set_buffer_uptodate(bhs[n]);
1212                        mark_buffer_dirty_inode(bhs[n], dir);
1213                        if (!size)
1214                                break;
1215                        n++;
1216                        blknr++;
1217                }
1218        } while (++i < *nr_cluster);
1219
1220        memset(bhs[n]->b_data + copy, 0, sb->s_blocksize - copy);
1221        offset = copy - sizeof(struct msdos_dir_entry);
1222        get_bh(bhs[n]);
1223        *bh = bhs[n];
1224        *de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
1225        *i_pos = fat_make_i_pos(sb, *bh, *de);
1226
1227        /* Second stage: clear the rest of cluster, and write outs */
1228        err = fat_zeroed_cluster(dir, start_blknr, ++n, bhs, MAX_BUF_PER_PAGE);
1229        if (err)
1230                goto error_free;
1231
1232        return cluster[0];
1233
1234error_free:
1235        brelse(*bh);
1236        *bh = NULL;
1237        n = 0;
1238error_nomem:
1239        for (i = 0; i < n; i++)
1240                bforget(bhs[i]);
1241        fat_free_clusters(dir, cluster[0]);
1242error:
1243        return err;
1244}
1245
1246int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
1247                    struct fat_slot_info *sinfo)
1248{
1249        struct super_block *sb = dir->i_sb;
1250        struct msdos_sb_info *sbi = MSDOS_SB(sb);
1251        struct buffer_head *bh, *prev, *bhs[3]; /* 32*slots (672bytes) */
1252        struct msdos_dir_entry *uninitialized_var(de);
1253        int err, free_slots, i, nr_bhs;
1254        loff_t pos, i_pos;
1255
1256        sinfo->nr_slots = nr_slots;
1257
1258        /* First stage: search free direcotry entries */
1259        free_slots = nr_bhs = 0;
1260        bh = prev = NULL;
1261        pos = 0;
1262        err = -ENOSPC;
1263        while (fat_get_entry(dir, &pos, &bh, &de) > -1) {
1264                /* check the maximum size of directory */
1265                if (pos >= FAT_MAX_DIR_SIZE)
1266                        goto error;
1267
1268                if (IS_FREE(de->name)) {
1269                        if (prev != bh) {
1270                                get_bh(bh);
1271                                bhs[nr_bhs] = prev = bh;
1272                                nr_bhs++;
1273                        }
1274                        free_slots++;
1275                        if (free_slots == nr_slots)
1276                                goto found;
1277                } else {
1278                        for (i = 0; i < nr_bhs; i++)
1279                                brelse(bhs[i]);
1280                        prev = NULL;
1281                        free_slots = nr_bhs = 0;
1282                }
1283        }
1284        if (dir->i_ino == MSDOS_ROOT_INO) {
1285                if (sbi->fat_bits != 32)
1286                        goto error;
1287        } else if (MSDOS_I(dir)->i_start == 0) {
1288                fat_msg(sb, KERN_ERR, "Corrupted directory (i_pos %lld)",
1289                       MSDOS_I(dir)->i_pos);
1290                err = -EIO;
1291                goto error;
1292        }
1293
1294found:
1295        err = 0;
1296        pos -= free_slots * sizeof(*de);
1297        nr_slots -= free_slots;
1298        if (free_slots) {
1299                /*
1300                 * Second stage: filling the free entries with new entries.
1301                 * NOTE: If this slots has shortname, first, we write
1302                 * the long name slots, then write the short name.
1303                 */
1304                int size = free_slots * sizeof(*de);
1305                int offset = pos & (sb->s_blocksize - 1);
1306                int long_bhs = nr_bhs - (nr_slots == 0);
1307
1308                /* Fill the long name slots. */
1309                for (i = 0; i < long_bhs; i++) {
1310                        int copy = min_t(int, sb->s_blocksize - offset, size);
1311                        memcpy(bhs[i]->b_data + offset, slots, copy);
1312                        mark_buffer_dirty_inode(bhs[i], dir);
1313                        offset = 0;
1314                        slots += copy;
1315                        size -= copy;
1316                }
1317                if (long_bhs && IS_DIRSYNC(dir))
1318                        err = fat_sync_bhs(bhs, long_bhs);
1319                if (!err && i < nr_bhs) {
1320                        /* Fill the short name slot. */
1321                        int copy = min_t(int, sb->s_blocksize - offset, size);
1322                        memcpy(bhs[i]->b_data + offset, slots, copy);
1323                        mark_buffer_dirty_inode(bhs[i], dir);
1324                        if (IS_DIRSYNC(dir))
1325                                err = sync_dirty_buffer(bhs[i]);
1326                }
1327                for (i = 0; i < nr_bhs; i++)
1328                        brelse(bhs[i]);
1329                if (err)
1330                        goto error_remove;
1331        }
1332
1333        if (nr_slots) {
1334                int cluster, nr_cluster;
1335
1336                /*
1337                 * Third stage: allocate the cluster for new entries.
1338                 * And initialize the cluster with new entries, then
1339                 * add the cluster to dir.
1340                 */
1341                cluster = fat_add_new_entries(dir, slots, nr_slots, &nr_cluster,
1342                                              &de, &bh, &i_pos);
1343                if (cluster < 0) {
1344                        err = cluster;
1345                        goto error_remove;
1346                }
1347                err = fat_chain_add(dir, cluster, nr_cluster);
1348                if (err) {
1349                        fat_free_clusters(dir, cluster);
1350                        goto error_remove;
1351                }
1352                if (dir->i_size & (sbi->cluster_size - 1)) {
1353                        fat_fs_error(sb, "Odd directory size");
1354                        dir->i_size = (dir->i_size + sbi->cluster_size - 1)
1355                                & ~((loff_t)sbi->cluster_size - 1);
1356                }
1357                dir->i_size += nr_cluster << sbi->cluster_bits;
1358                MSDOS_I(dir)->mmu_private += nr_cluster << sbi->cluster_bits;
1359        }
1360        sinfo->slot_off = pos;
1361        sinfo->de = de;
1362        sinfo->bh = bh;
1363        sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
1364
1365        return 0;
1366
1367error:
1368        brelse(bh);
1369        for (i = 0; i < nr_bhs; i++)
1370                brelse(bhs[i]);
1371        return err;
1372
1373error_remove:
1374        brelse(bh);
1375        if (free_slots)
1376                __fat_remove_entries(dir, pos, free_slots);
1377        return err;
1378}
1379EXPORT_SYMBOL_GPL(fat_add_entries);
1380
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