LXR linux/fs/fat/namei

   1/*
   2 *  linux/fs/msdos/namei.c
   3 *
   4 *  Written 1992,1993 by Werner Almesberger
   5 *  Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu>
   6 *  Rewritten for constant inumbers 1999 by Al Viro
   7 */
   8
   9#include <linux/module.h>
  10#include <linux/time.h>
  11#include <linux/buffer_head.h>
  12#include "fat.h"
  13
  14/* Characters that are undesirable in an MS-DOS file name */
  15static unsigned char bad_chars[] = "*?<>|\"";
  16static unsigned char bad_if_strict[] = "+=,; ";
  17
  18/***** Formats an MS-DOS file name. Rejects invalid names. */
  19static int msdos_format_name(const unsigned char *name, int len,
  20                             unsigned char *res, struct fat_mount_options *opts)
  21        /*
  22         * name is the proposed name, len is its length, res is
  23         * the resulting name, opts->name_check is either (r)elaxed,
  24         * (n)ormal or (s)trict, opts->dotsOK allows dots at the
  25         * beginning of name (for hidden files)
  26         */
  27{
  28        unsigned char *walk;
  29        unsigned char c;
  30        int space;
  31
  32        if (name[0] == '.') {   /* dotfile because . and .. already done */
  33                if (opts->dotsOK) {
  34                        /* Get rid of dot - test for it elsewhere */
  35                        name++;
  36                        len--;
  37                } else
  38                        return -EINVAL;
  39        }
  40        /*
  41         * disallow names that _really_ start with a dot
  42         */
  43        space = 1;
  44        c = 0;
  45        for (walk = res; len && walk - res < 8; walk++) {
  46                c = *name++;
  47                len--;
  48                if (opts->name_check != 'r' && strchr(bad_chars, c))
  49                        return -EINVAL;
  50                if (opts->name_check == 's' && strchr(bad_if_strict, c))
  51                        return -EINVAL;
  52                if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
  53                        return -EINVAL;
  54                if (c < ' ' || c == ':' || c == '\\')
  55                        return -EINVAL;
  56        /*
  57         * 0xE5 is legal as a first character, but we must substitute
  58         * 0x05 because 0xE5 marks deleted files.  Yes, DOS really
  59         * does this.
  60         * It seems that Microsoft hacked DOS to support non-US
  61         * characters after the 0xE5 character was already in use to
  62         * mark deleted files.
  63         */
  64                if ((res == walk) && (c == 0xE5))
  65                        c = 0x05;
  66                if (c == '.')
  67                        break;
  68                space = (c == ' ');
  69                *walk = (!opts->nocase && c >= 'a' && c <= 'z') ? c - 32 : c;
  70        }
  71        if (space)
  72                return -EINVAL;
  73        if (opts->name_check == 's' && len && c != '.') {
  74                c = *name++;
  75                len--;
  76                if (c != '.')
  77                        return -EINVAL;
  78        }
  79        while (c != '.' && len--)
  80                c = *name++;
  81        if (c == '.') {
  82                while (walk - res < 8)
  83                        *walk++ = ' ';
  84                while (len > 0 && walk - res < MSDOS_NAME) {
  85                        c = *name++;
  86                        len--;
  87                        if (opts->name_check != 'r' && strchr(bad_chars, c))
  88                                return -EINVAL;
  89                        if (opts->name_check == 's' &&
  90                            strchr(bad_if_strict, c))
  91                                return -EINVAL;
  92                        if (c < ' ' || c == ':' || c == '\\')
  93                                return -EINVAL;
  94                        if (c == '.') {
  95                                if (opts->name_check == 's')
  96                                        return -EINVAL;
  97                                break;
  98                        }
  99                        if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
 100                                return -EINVAL;
 101                        space = c == ' ';
 102                        if (!opts->nocase && c >= 'a' && c <= 'z')
 103                                *walk++ = c - 32;
 104                        else
 105                                *walk++ = c;
 106                }
 107                if (space)
 108                        return -EINVAL;
 109                if (opts->name_check == 's' && len)
 110                        return -EINVAL;
 111        }
 112        while (walk - res < MSDOS_NAME)
 113                *walk++ = ' ';
 114
 115        return 0;
 116}
 117
 118/***** Locates a directory entry.  Uses unformatted name. */
 119static int msdos_find(struct inode *dir, const unsigned char *name, int len,
 120                      struct fat_slot_info *sinfo)
 121{
 122        struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
 123        unsigned char msdos_name[MSDOS_NAME];
 124        int err;
 125
 126        err = msdos_format_name(name, len, msdos_name, &sbi->options);
 127        if (err)
 128                return -ENOENT;
 129
 130        err = fat_scan(dir, msdos_name, sinfo);
 131        if (!err && sbi->options.dotsOK) {
 132                if (name[0] == '.') {
 133                        if (!(sinfo->de->attr & ATTR_HIDDEN))
 134                                err = -ENOENT;
 135                } else {
 136                        if (sinfo->de->attr & ATTR_HIDDEN)
 137                                err = -ENOENT;
 138                }
 139                if (err)
 140                        brelse(sinfo->bh);
 141        }
 142        return err;
 143}
 144
 145/*
 146 * Compute the hash for the msdos name corresponding to the dentry.
 147 * Note: if the name is invalid, we leave the hash code unchanged so
 148 * that the existing dentry can be used. The msdos fs routines will
 149 * return ENOENT or EINVAL as appropriate.
 150 */
 151static int msdos_hash(struct dentry *dentry, struct qstr *qstr)
 152{
 153        struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
 154        unsigned char msdos_name[MSDOS_NAME];
 155        int error;
 156
 157        error = msdos_format_name(qstr->name, qstr->len, msdos_name, options);
 158        if (!error)
 159                qstr->hash = full_name_hash(msdos_name, MSDOS_NAME);
 160        return 0;
 161}
 162
 163/*
 164 * Compare two msdos names. If either of the names are invalid,
 165 * we fall back to doing the standard name comparison.
 166 */
 167static int msdos_cmp(struct dentry *dentry, struct qstr *a, struct qstr *b)
 168{
 169        struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
 170        unsigned char a_msdos_name[MSDOS_NAME], b_msdos_name[MSDOS_NAME];
 171        int error;
 172
 173        error = msdos_format_name(a->name, a->len, a_msdos_name, options);
 174        if (error)
 175                goto old_compare;
 176        error = msdos_format_name(b->name, b->len, b_msdos_name, options);
 177        if (error)
 178                goto old_compare;
 179        error = memcmp(a_msdos_name, b_msdos_name, MSDOS_NAME);
 180out:
 181        return error;
 182
 183old_compare:
 184        error = 1;
 185        if (a->len == b->len)
 186                error = memcmp(a->name, b->name, a->len);
 187        goto out;
 188}
 189
 190static const struct dentry_operations msdos_dentry_operations = {
 191        .d_hash         = msdos_hash,
 192        .d_compare      = msdos_cmp,
 193};
 194
 195/*
 196 * AV. Wrappers for FAT sb operations. Is it wise?
 197 */
 198
 199/***** Get inode using directory and name */
 200static struct dentry *msdos_lookup(struct inode *dir, struct dentry *dentry,
 201                                   struct nameidata *nd)
 202{
 203        struct super_block *sb = dir->i_sb;
 204        struct fat_slot_info sinfo;
 205        struct inode *inode;
 206        int err;
 207
 208        lock_super(sb);
 209
 210        err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
 211        if (err) {
 212                if (err == -ENOENT) {
 213                        inode = NULL;
 214                        goto out;
 215                }
 216                goto error;
 217        }
 218
 219        inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
 220        brelse(sinfo.bh);
 221        if (IS_ERR(inode)) {
 222                err = PTR_ERR(inode);
 223                goto error;
 224        }
 225out:
 226        unlock_super(sb);
 227        dentry->d_op = &msdos_dentry_operations;
 228        dentry = d_splice_alias(inode, dentry);
 229        if (dentry)
 230                dentry->d_op = &msdos_dentry_operations;
 231        return dentry;
 232
 233error:
 234        unlock_super(sb);
 235        return ERR_PTR(err);
 236}
 237
 238/***** Creates a directory entry (name is already formatted). */
 239static int msdos_add_entry(struct inode *dir, const unsigned char *name,
 240                           int is_dir, int is_hid, int cluster,
 241                           struct timespec *ts, struct fat_slot_info *sinfo)
 242{
 243        struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
 244        struct msdos_dir_entry de;
 245        __le16 time, date;
 246        int err;
 247
 248        memcpy(de.name, name, MSDOS_NAME);
 249        de.attr = is_dir ? ATTR_DIR : ATTR_ARCH;
 250        if (is_hid)
 251                de.attr |= ATTR_HIDDEN;
 252        de.lcase = 0;
 253        fat_time_unix2fat(sbi, ts, &time, &date, NULL);
 254        de.cdate = de.adate = 0;
 255        de.ctime = 0;
 256        de.ctime_cs = 0;
 257        de.time = time;
 258        de.date = date;
 259        de.start = cpu_to_le16(cluster);
 260        de.starthi = cpu_to_le16(cluster >> 16);
 261        de.size = 0;
 262
 263        err = fat_add_entries(dir, &de, 1, sinfo);
 264        if (err)
 265                return err;
 266
 267        dir->i_ctime = dir->i_mtime = *ts;
 268        if (IS_DIRSYNC(dir))
 269                (void)fat_sync_inode(dir);
 270        else
 271                mark_inode_dirty(dir);
 272
 273        return 0;
 274}
 275
 276/***** Create a file */
 277static int msdos_create(struct inode *dir, struct dentry *dentry, int mode,
 278                        struct nameidata *nd)
 279{
 280        struct super_block *sb = dir->i_sb;
 281        struct inode *inode = NULL;
 282        struct fat_slot_info sinfo;
 283        struct timespec ts;
 284        unsigned char msdos_name[MSDOS_NAME];
 285        int err, is_hid;
 286
 287        lock_super(sb);
 288
 289        err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
 290                                msdos_name, &MSDOS_SB(sb)->options);
 291        if (err)
 292                goto out;
 293        is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
 294        /* Have to do it due to foo vs. .foo conflicts */
 295        if (!fat_scan(dir, msdos_name, &sinfo)) {
 296                brelse(sinfo.bh);
 297                err = -EINVAL;
 298                goto out;
 299        }
 300
 301        ts = CURRENT_TIME_SEC;
 302        err = msdos_add_entry(dir, msdos_name, 0, is_hid, 0, &ts, &sinfo);
 303        if (err)
 304                goto out;
 305        inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
 306        brelse(sinfo.bh);
 307        if (IS_ERR(inode)) {
 308                err = PTR_ERR(inode);
 309                goto out;
 310        }
 311        inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
 312        /* timestamp is already written, so mark_inode_dirty() is unneeded. */
 313
 314        d_instantiate(dentry, inode);
 315out:
 316        unlock_super(sb);
 317        if (!err)
 318                err = fat_flush_inodes(sb, dir, inode);
 319        return err;
 320}
 321
 322/***** Remove a directory */
 323static int msdos_rmdir(struct inode *dir, struct dentry *dentry)
 324{
 325        struct super_block *sb = dir->i_sb;
 326        struct inode *inode = dentry->d_inode;
 327        struct fat_slot_info sinfo;
 328        int err;
 329
 330        lock_super(sb);
 331        /*
 332         * Check whether the directory is not in use, then check
 333         * whether it is empty.
 334         */
 335        err = fat_dir_empty(inode);
 336        if (err)
 337                goto out;
 338        err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
 339        if (err)
 340                goto out;
 341
 342        err = fat_remove_entries(dir, &sinfo);  /* and releases bh */
 343        if (err)
 344                goto out;
 345        drop_nlink(dir);
 346
 347        clear_nlink(inode);
 348        inode->i_ctime = CURRENT_TIME_SEC;
 349        fat_detach(inode);
 350out:
 351        unlock_super(sb);
 352        if (!err)
 353                err = fat_flush_inodes(sb, dir, inode);
 354
 355        return err;
 356}
 357
 358/***** Make a directory */
 359static int msdos_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 360{
 361        struct super_block *sb = dir->i_sb;
 362        struct fat_slot_info sinfo;
 363        struct inode *inode;
 364        unsigned char msdos_name[MSDOS_NAME];
 365        struct timespec ts;
 366        int err, is_hid, cluster;
 367
 368        lock_super(sb);
 369
 370        err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
 371                                msdos_name, &MSDOS_SB(sb)->options);
 372        if (err)
 373                goto out;
 374        is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
 375        /* foo vs .foo situation */
 376        if (!fat_scan(dir, msdos_name, &sinfo)) {
 377                brelse(sinfo.bh);
 378                err = -EINVAL;
 379                goto out;
 380        }
 381
 382        ts = CURRENT_TIME_SEC;
 383        cluster = fat_alloc_new_dir(dir, &ts);
 384        if (cluster < 0) {
 385                err = cluster;
 386                goto out;
 387        }
 388        err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
 389        if (err)
 390                goto out_free;
 391        inc_nlink(dir);
 392
 393        inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
 394        brelse(sinfo.bh);
 395        if (IS_ERR(inode)) {
 396                err = PTR_ERR(inode);
 397                /* the directory was completed, just return a error */
 398                goto out;
 399        }
 400        inode->i_nlink = 2;
 401        inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
 402        /* timestamp is already written, so mark_inode_dirty() is unneeded. */
 403
 404        d_instantiate(dentry, inode);
 405
 406        unlock_super(sb);
 407        fat_flush_inodes(sb, dir, inode);
 408        return 0;
 409
 410out_free:
 411        fat_free_clusters(dir, cluster);
 412out:
 413        unlock_super(sb);
 414        return err;
 415}
 416
 417/***** Unlink a file */
 418static int msdos_unlink(struct inode *dir, struct dentry *dentry)
 419{
 420        struct inode *inode = dentry->d_inode;
 421        struct super_block *sb= inode->i_sb;
 422        struct fat_slot_info sinfo;
 423        int err;
 424
 425        lock_super(sb);
 426        err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
 427        if (err)
 428                goto out;
 429
 430        err = fat_remove_entries(dir, &sinfo);  /* and releases bh */
 431        if (err)
 432                goto out;
 433        clear_nlink(inode);
 434        inode->i_ctime = CURRENT_TIME_SEC;
 435        fat_detach(inode);
 436out:
 437        unlock_super(sb);
 438        if (!err)
 439                err = fat_flush_inodes(sb, dir, inode);
 440
 441        return err;
 442}
 443
 444static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
 445                           struct dentry *old_dentry,
 446                           struct inode *new_dir, unsigned char *new_name,
 447                           struct dentry *new_dentry, int is_hid)
 448{
 449        struct buffer_head *dotdot_bh;
 450        struct msdos_dir_entry *dotdot_de;
 451        struct inode *old_inode, *new_inode;
 452        struct fat_slot_info old_sinfo, sinfo;
 453        struct timespec ts;
 454        loff_t dotdot_i_pos, new_i_pos;
 455        int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
 456
 457        old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
 458        old_inode = old_dentry->d_inode;
 459        new_inode = new_dentry->d_inode;
 460
 461        err = fat_scan(old_dir, old_name, &old_sinfo);
 462        if (err) {
 463                err = -EIO;
 464                goto out;
 465        }
 466
 467        is_dir = S_ISDIR(old_inode->i_mode);
 468        update_dotdot = (is_dir && old_dir != new_dir);
 469        if (update_dotdot) {
 470                if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de,
 471                                         &dotdot_i_pos) < 0) {
 472                        err = -EIO;
 473                        goto out;
 474                }
 475        }
 476
 477        old_attrs = MSDOS_I(old_inode)->i_attrs;
 478        err = fat_scan(new_dir, new_name, &sinfo);
 479        if (!err) {
 480                if (!new_inode) {
 481                        /* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
 482                        if (sinfo.de != old_sinfo.de) {
 483                                err = -EINVAL;
 484                                goto out;
 485                        }
 486                        if (is_hid)
 487                                MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
 488                        else
 489                                MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
 490                        if (IS_DIRSYNC(old_dir)) {
 491                                err = fat_sync_inode(old_inode);
 492                                if (err) {
 493                                        MSDOS_I(old_inode)->i_attrs = old_attrs;
 494                                        goto out;
 495                                }
 496                        } else
 497                                mark_inode_dirty(old_inode);
 498
 499                        old_dir->i_version++;
 500                        old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
 501                        if (IS_DIRSYNC(old_dir))
 502                                (void)fat_sync_inode(old_dir);
 503                        else
 504                                mark_inode_dirty(old_dir);
 505                        goto out;
 506                }
 507        }
 508
 509        ts = CURRENT_TIME_SEC;
 510        if (new_inode) {
 511                if (err)
 512                        goto out;
 513                if (is_dir) {
 514                        err = fat_dir_empty(new_inode);
 515                        if (err)
 516                                goto out;
 517                }
 518                new_i_pos = MSDOS_I(new_inode)->i_pos;
 519                fat_detach(new_inode);
 520        } else {
 521                err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
 522                                      &ts, &sinfo);
 523                if (err)
 524                        goto out;
 525                new_i_pos = sinfo.i_pos;
 526        }
 527        new_dir->i_version++;
 528
 529        fat_detach(old_inode);
 530        fat_attach(old_inode, new_i_pos);
 531        if (is_hid)
 532                MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
 533        else
 534                MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
 535        if (IS_DIRSYNC(new_dir)) {
 536                err = fat_sync_inode(old_inode);
 537                if (err)
 538                        goto error_inode;
 539        } else
 540                mark_inode_dirty(old_inode);
 541
 542        if (update_dotdot) {
 543                int start = MSDOS_I(new_dir)->i_logstart;
 544                dotdot_de->start = cpu_to_le16(start);
 545                dotdot_de->starthi = cpu_to_le16(start >> 16);
 546                mark_buffer_dirty_inode(dotdot_bh, old_inode);
 547                if (IS_DIRSYNC(new_dir)) {
 548                        err = sync_dirty_buffer(dotdot_bh);
 549                        if (err)
 550                                goto error_dotdot;
 551                }
 552                drop_nlink(old_dir);
 553                if (!new_inode)
 554                        inc_nlink(new_dir);
 555        }
 556
 557        err = fat_remove_entries(old_dir, &old_sinfo);  /* and releases bh */
 558        old_sinfo.bh = NULL;
 559        if (err)
 560                goto error_dotdot;
 561        old_dir->i_version++;
 562        old_dir->i_ctime = old_dir->i_mtime = ts;
 563        if (IS_DIRSYNC(old_dir))
 564                (void)fat_sync_inode(old_dir);
 565        else
 566                mark_inode_dirty(old_dir);
 567
 568        if (new_inode) {
 569                drop_nlink(new_inode);
 570                if (is_dir)
 571                        drop_nlink(new_inode);
 572                new_inode->i_ctime = ts;
 573        }
 574out:
 575        brelse(sinfo.bh);
 576        brelse(dotdot_bh);
 577        brelse(old_sinfo.bh);
 578        return err;
 579
 580error_dotdot:
 581        /* data cluster is shared, serious corruption */
 582        corrupt = 1;
 583
 584        if (update_dotdot) {
 585                int start = MSDOS_I(old_dir)->i_logstart;
 586                dotdot_de->start = cpu_to_le16(start);
 587                dotdot_de->starthi = cpu_to_le16(start >> 16);
 588                mark_buffer_dirty_inode(dotdot_bh, old_inode);
 589                corrupt |= sync_dirty_buffer(dotdot_bh);
 590        }
 591error_inode:
 592        fat_detach(old_inode);
 593        fat_attach(old_inode, old_sinfo.i_pos);
 594        MSDOS_I(old_inode)->i_attrs = old_attrs;
 595        if (new_inode) {
 596                fat_attach(new_inode, new_i_pos);
 597                if (corrupt)
 598                        corrupt |= fat_sync_inode(new_inode);
 599        } else {
 600                /*
 601                 * If new entry was not sharing the data cluster, it
 602                 * shouldn't be serious corruption.
 603                 */
 604                int err2 = fat_remove_entries(new_dir, &sinfo);
 605                if (corrupt)
 606                        corrupt |= err2;
 607                sinfo.bh = NULL;
 608        }
 609        if (corrupt < 0) {
 610                fat_fs_error(new_dir->i_sb,
 611                             "%s: Filesystem corrupted (i_pos %lld)",
 612                             __func__, sinfo.i_pos);
 613        }
 614        goto out;
 615}
 616
 617/***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
 618static int msdos_rename(struct inode *old_dir, struct dentry *old_dentry,
 619                        struct inode *new_dir, struct dentry *new_dentry)
 620{
 621        struct super_block *sb = old_dir->i_sb;
 622        unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
 623        int err, is_hid;
 624
 625        lock_super(sb);
 626
 627        err = msdos_format_name(old_dentry->d_name.name,
 628                                old_dentry->d_name.len, old_msdos_name,
 629                                &MSDOS_SB(old_dir->i_sb)->options);
 630        if (err)
 631                goto out;
 632        err = msdos_format_name(new_dentry->d_name.name,
 633                                new_dentry->d_name.len, new_msdos_name,
 634                                &MSDOS_SB(new_dir->i_sb)->options);
 635        if (err)
 636                goto out;
 637
 638        is_hid =
 639             (new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');
 640
 641        err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
 642                              new_dir, new_msdos_name, new_dentry, is_hid);
 643out:
 644        unlock_super(sb);
 645        if (!err)
 646                err = fat_flush_inodes(sb, old_dir, new_dir);
 647        return err;
 648}
 649
 650static const struct inode_operations msdos_dir_inode_operations = {
 651        .create         = msdos_create,
 652        .lookup         = msdos_lookup,
 653        .unlink         = msdos_unlink,
 654        .mkdir          = msdos_mkdir,
 655        .rmdir          = msdos_rmdir,
 656        .rename         = msdos_rename,
 657        .setattr        = fat_setattr,
 658        .getattr        = fat_getattr,
 659};
 660
 661static int msdos_fill_super(struct super_block *sb, void *data, int silent)
 662{
 663        int res;
 664
 665        res = fat_fill_super(sb, data, silent, &msdos_dir_inode_operations, 0);
 666        if (res)
 667                return res;
 668
 669        sb->s_flags |= MS_NOATIME;
 670        sb->s_root->d_op = &msdos_dentry_operations;
 671        return 0;
 672}
 673
 674static int msdos_get_sb(struct file_system_type *fs_type,
 675                        int flags, const char *dev_name,
 676                        void *data, struct vfsmount *mnt)
 677{
 678        return get_sb_bdev(fs_type, flags, dev_name, data, msdos_fill_super,
 679                           mnt);
 680}
 681
 682static struct file_system_type msdos_fs_type = {
 683        .owner          = THIS_MODULE,
 684        .name           = "msdos",
 685        .get_sb         = msdos_get_sb,
 686        .kill_sb        = kill_block_super,
 687        .fs_flags       = FS_REQUIRES_DEV,
 688};
 689
 690static int __init init_msdos_fs(void)
 691{
 692        return register_filesystem(&msdos_fs_type);
 693}
 694
 695static void __exit exit_msdos_fs(void)
 696{
 697        unregister_filesystem(&msdos_fs_type);
 698}
 699
 700MODULE_LICENSE("GPL");
 701MODULE_AUTHOR("Werner Almesberger");
 702MODULE_DESCRIPTION("MS-DOS filesystem support");
 703
 704module_init(init_msdos_fs)
 705module_exit(exit_msdos_fs)
 706