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(const 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(const struct dentry *parent, const struct dentry *dentry,
 168                unsigned int len, const char *str, const struct qstr *name)
 169{
 170        struct fat_mount_options *options = &MSDOS_SB(parent->d_sb)->options;
 171        unsigned char a_msdos_name[MSDOS_NAME], b_msdos_name[MSDOS_NAME];
 172        int error;
 173
 174        error = msdos_format_name(name->name, name->len, a_msdos_name, options);
 175        if (error)
 176                goto old_compare;
 177        error = msdos_format_name(str, len, b_msdos_name, options);
 178        if (error)
 179                goto old_compare;
 180        error = memcmp(a_msdos_name, b_msdos_name, MSDOS_NAME);
 181out:
 182        return error;
 183
 184old_compare:
 185        error = 1;
 186        if (name->len == len)
 187                error = memcmp(name->name, str, len);
 188        goto out;
 189}
 190
 191static const struct dentry_operations msdos_dentry_operations = {
 192        .d_hash         = msdos_hash,
 193        .d_compare      = msdos_cmp,
 194};
 195
 196/*
 197 * AV. Wrappers for FAT sb operations. Is it wise?
 198 */
 199
 200/***** Get inode using directory and name */
 201static struct dentry *msdos_lookup(struct inode *dir, struct dentry *dentry,
 202                                   unsigned int flags)
 203{
 204        struct super_block *sb = dir->i_sb;
 205        struct fat_slot_info sinfo;
 206        struct inode *inode;
 207        int err;
 208
 209        mutex_lock(&MSDOS_SB(sb)->s_lock);
 210        err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
 211        switch (err) {
 212        case -ENOENT:
 213                inode = NULL;
 214                break;
 215        case 0:
 216                inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
 217                brelse(sinfo.bh);
 218                break;
 219        default:
 220                inode = ERR_PTR(err);
 221        }
 222        mutex_unlock(&MSDOS_SB(sb)->s_lock);
 223        return d_splice_alias(inode, dentry);
 224}
 225
 226/***** Creates a directory entry (name is already formatted). */
 227static int msdos_add_entry(struct inode *dir, const unsigned char *name,
 228                           int is_dir, int is_hid, int cluster,
 229                           struct timespec *ts, struct fat_slot_info *sinfo)
 230{
 231        struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
 232        struct msdos_dir_entry de;
 233        __le16 time, date;
 234        int err;
 235
 236        memcpy(de.name, name, MSDOS_NAME);
 237        de.attr = is_dir ? ATTR_DIR : ATTR_ARCH;
 238        if (is_hid)
 239                de.attr |= ATTR_HIDDEN;
 240        de.lcase = 0;
 241        fat_time_unix2fat(sbi, ts, &time, &date, NULL);
 242        de.cdate = de.adate = 0;
 243        de.ctime = 0;
 244        de.ctime_cs = 0;
 245        de.time = time;
 246        de.date = date;
 247        fat_set_start(&de, cluster);
 248        de.size = 0;
 249
 250        err = fat_add_entries(dir, &de, 1, sinfo);
 251        if (err)
 252                return err;
 253
 254        dir->i_ctime = dir->i_mtime = *ts;
 255        if (IS_DIRSYNC(dir))
 256                (void)fat_sync_inode(dir);
 257        else
 258                mark_inode_dirty(dir);
 259
 260        return 0;
 261}
 262
 263/***** Create a file */
 264static int msdos_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 265                        bool excl)
 266{
 267        struct super_block *sb = dir->i_sb;
 268        struct inode *inode = NULL;
 269        struct fat_slot_info sinfo;
 270        struct timespec ts;
 271        unsigned char msdos_name[MSDOS_NAME];
 272        int err, is_hid;
 273
 274        mutex_lock(&MSDOS_SB(sb)->s_lock);
 275
 276        err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
 277                                msdos_name, &MSDOS_SB(sb)->options);
 278        if (err)
 279                goto out;
 280        is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
 281        /* Have to do it due to foo vs. .foo conflicts */
 282        if (!fat_scan(dir, msdos_name, &sinfo)) {
 283                brelse(sinfo.bh);
 284                err = -EINVAL;
 285                goto out;
 286        }
 287
 288        ts = CURRENT_TIME_SEC;
 289        err = msdos_add_entry(dir, msdos_name, 0, is_hid, 0, &ts, &sinfo);
 290        if (err)
 291                goto out;
 292        inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
 293        brelse(sinfo.bh);
 294        if (IS_ERR(inode)) {
 295                err = PTR_ERR(inode);
 296                goto out;
 297        }
 298        inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
 299        /* timestamp is already written, so mark_inode_dirty() is unneeded. */
 300
 301        d_instantiate(dentry, inode);
 302out:
 303        mutex_unlock(&MSDOS_SB(sb)->s_lock);
 304        if (!err)
 305                err = fat_flush_inodes(sb, dir, inode);
 306        return err;
 307}
 308
 309/***** Remove a directory */
 310static int msdos_rmdir(struct inode *dir, struct dentry *dentry)
 311{
 312        struct super_block *sb = dir->i_sb;
 313        struct inode *inode = dentry->d_inode;
 314        struct fat_slot_info sinfo;
 315        int err;
 316
 317        mutex_lock(&MSDOS_SB(sb)->s_lock);
 318        /*
 319         * Check whether the directory is not in use, then check
 320         * whether it is empty.
 321         */
 322        err = fat_dir_empty(inode);
 323        if (err)
 324                goto out;
 325        err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
 326        if (err)
 327                goto out;
 328
 329        err = fat_remove_entries(dir, &sinfo);  /* and releases bh */
 330        if (err)
 331                goto out;
 332        drop_nlink(dir);
 333
 334        clear_nlink(inode);
 335        inode->i_ctime = CURRENT_TIME_SEC;
 336        fat_detach(inode);
 337out:
 338        mutex_unlock(&MSDOS_SB(sb)->s_lock);
 339        if (!err)
 340                err = fat_flush_inodes(sb, dir, inode);
 341
 342        return err;
 343}
 344
 345/***** Make a directory */
 346static int msdos_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 347{
 348        struct super_block *sb = dir->i_sb;
 349        struct fat_slot_info sinfo;
 350        struct inode *inode;
 351        unsigned char msdos_name[MSDOS_NAME];
 352        struct timespec ts;
 353        int err, is_hid, cluster;
 354
 355        mutex_lock(&MSDOS_SB(sb)->s_lock);
 356
 357        err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
 358                                msdos_name, &MSDOS_SB(sb)->options);
 359        if (err)
 360                goto out;
 361        is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
 362        /* foo vs .foo situation */
 363        if (!fat_scan(dir, msdos_name, &sinfo)) {
 364                brelse(sinfo.bh);
 365                err = -EINVAL;
 366                goto out;
 367        }
 368
 369        ts = CURRENT_TIME_SEC;
 370        cluster = fat_alloc_new_dir(dir, &ts);
 371        if (cluster < 0) {
 372                err = cluster;
 373                goto out;
 374        }
 375        err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
 376        if (err)
 377                goto out_free;
 378        inc_nlink(dir);
 379
 380        inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
 381        brelse(sinfo.bh);
 382        if (IS_ERR(inode)) {
 383                err = PTR_ERR(inode);
 384                /* the directory was completed, just return a error */
 385                goto out;
 386        }
 387        set_nlink(inode, 2);
 388        inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
 389        /* timestamp is already written, so mark_inode_dirty() is unneeded. */
 390
 391        d_instantiate(dentry, inode);
 392
 393        mutex_unlock(&MSDOS_SB(sb)->s_lock);
 394        fat_flush_inodes(sb, dir, inode);
 395        return 0;
 396
 397out_free:
 398        fat_free_clusters(dir, cluster);
 399out:
 400        mutex_unlock(&MSDOS_SB(sb)->s_lock);
 401        return err;
 402}
 403
 404/***** Unlink a file */
 405static int msdos_unlink(struct inode *dir, struct dentry *dentry)
 406{
 407        struct inode *inode = dentry->d_inode;
 408        struct super_block *sb = inode->i_sb;
 409        struct fat_slot_info sinfo;
 410        int err;
 411
 412        mutex_lock(&MSDOS_SB(sb)->s_lock);
 413        err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
 414        if (err)
 415                goto out;
 416
 417        err = fat_remove_entries(dir, &sinfo);  /* and releases bh */
 418        if (err)
 419                goto out;
 420        clear_nlink(inode);
 421        inode->i_ctime = CURRENT_TIME_SEC;
 422        fat_detach(inode);
 423out:
 424        mutex_unlock(&MSDOS_SB(sb)->s_lock);
 425        if (!err)
 426                err = fat_flush_inodes(sb, dir, inode);
 427
 428        return err;
 429}
 430
 431static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
 432                           struct dentry *old_dentry,
 433                           struct inode *new_dir, unsigned char *new_name,
 434                           struct dentry *new_dentry, int is_hid)
 435{
 436        struct buffer_head *dotdot_bh;
 437        struct msdos_dir_entry *dotdot_de;
 438        struct inode *old_inode, *new_inode;
 439        struct fat_slot_info old_sinfo, sinfo;
 440        struct timespec ts;
 441        loff_t new_i_pos;
 442        int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
 443
 444        old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
 445        old_inode = old_dentry->d_inode;
 446        new_inode = new_dentry->d_inode;
 447
 448        err = fat_scan(old_dir, old_name, &old_sinfo);
 449        if (err) {
 450                err = -EIO;
 451                goto out;
 452        }
 453
 454        is_dir = S_ISDIR(old_inode->i_mode);
 455        update_dotdot = (is_dir && old_dir != new_dir);
 456        if (update_dotdot) {
 457                if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de)) {
 458                        err = -EIO;
 459                        goto out;
 460                }
 461        }
 462
 463        old_attrs = MSDOS_I(old_inode)->i_attrs;
 464        err = fat_scan(new_dir, new_name, &sinfo);
 465        if (!err) {
 466                if (!new_inode) {
 467                        /* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
 468                        if (sinfo.de != old_sinfo.de) {
 469                                err = -EINVAL;
 470                                goto out;
 471                        }
 472                        if (is_hid)
 473                                MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
 474                        else
 475                                MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
 476                        if (IS_DIRSYNC(old_dir)) {
 477                                err = fat_sync_inode(old_inode);
 478                                if (err) {
 479                                        MSDOS_I(old_inode)->i_attrs = old_attrs;
 480                                        goto out;
 481                                }
 482                        } else
 483                                mark_inode_dirty(old_inode);
 484
 485                        old_dir->i_version++;
 486                        old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
 487                        if (IS_DIRSYNC(old_dir))
 488                                (void)fat_sync_inode(old_dir);
 489                        else
 490                                mark_inode_dirty(old_dir);
 491                        goto out;
 492                }
 493        }
 494
 495        ts = CURRENT_TIME_SEC;
 496        if (new_inode) {
 497                if (err)
 498                        goto out;
 499                if (is_dir) {
 500                        err = fat_dir_empty(new_inode);
 501                        if (err)
 502                                goto out;
 503                }
 504                new_i_pos = MSDOS_I(new_inode)->i_pos;
 505                fat_detach(new_inode);
 506        } else {
 507                err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
 508                                      &ts, &sinfo);
 509                if (err)
 510                        goto out;
 511                new_i_pos = sinfo.i_pos;
 512        }
 513        new_dir->i_version++;
 514
 515        fat_detach(old_inode);
 516        fat_attach(old_inode, new_i_pos);
 517        if (is_hid)
 518                MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
 519        else
 520                MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
 521        if (IS_DIRSYNC(new_dir)) {
 522                err = fat_sync_inode(old_inode);
 523                if (err)
 524                        goto error_inode;
 525        } else
 526                mark_inode_dirty(old_inode);
 527
 528        if (update_dotdot) {
 529                fat_set_start(dotdot_de, MSDOS_I(new_dir)->i_logstart);
 530                mark_buffer_dirty_inode(dotdot_bh, old_inode);
 531                if (IS_DIRSYNC(new_dir)) {
 532                        err = sync_dirty_buffer(dotdot_bh);
 533                        if (err)
 534                                goto error_dotdot;
 535                }
 536                drop_nlink(old_dir);
 537                if (!new_inode)
 538                        inc_nlink(new_dir);
 539        }
 540
 541        err = fat_remove_entries(old_dir, &old_sinfo);  /* and releases bh */
 542        old_sinfo.bh = NULL;
 543        if (err)
 544                goto error_dotdot;
 545        old_dir->i_version++;
 546        old_dir->i_ctime = old_dir->i_mtime = ts;
 547        if (IS_DIRSYNC(old_dir))
 548                (void)fat_sync_inode(old_dir);
 549        else
 550                mark_inode_dirty(old_dir);
 551
 552        if (new_inode) {
 553                drop_nlink(new_inode);
 554                if (is_dir)
 555                        drop_nlink(new_inode);
 556                new_inode->i_ctime = ts;
 557        }
 558out:
 559        brelse(sinfo.bh);
 560        brelse(dotdot_bh);
 561        brelse(old_sinfo.bh);
 562        return err;
 563
 564error_dotdot:
 565        /* data cluster is shared, serious corruption */
 566        corrupt = 1;
 567
 568        if (update_dotdot) {
 569                fat_set_start(dotdot_de, MSDOS_I(old_dir)->i_logstart);
 570                mark_buffer_dirty_inode(dotdot_bh, old_inode);
 571                corrupt |= sync_dirty_buffer(dotdot_bh);
 572        }
 573error_inode:
 574        fat_detach(old_inode);
 575        fat_attach(old_inode, old_sinfo.i_pos);
 576        MSDOS_I(old_inode)->i_attrs = old_attrs;
 577        if (new_inode) {
 578                fat_attach(new_inode, new_i_pos);
 579                if (corrupt)
 580                        corrupt |= fat_sync_inode(new_inode);
 581        } else {
 582                /*
 583                 * If new entry was not sharing the data cluster, it
 584                 * shouldn't be serious corruption.
 585                 */
 586                int err2 = fat_remove_entries(new_dir, &sinfo);
 587                if (corrupt)
 588                        corrupt |= err2;
 589                sinfo.bh = NULL;
 590        }
 591        if (corrupt < 0) {
 592                fat_fs_error(new_dir->i_sb,
 593                             "%s: Filesystem corrupted (i_pos %lld)",
 594                             __func__, sinfo.i_pos);
 595        }
 596        goto out;
 597}
 598
 599/***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
 600static int msdos_rename(struct inode *old_dir, struct dentry *old_dentry,
 601                        struct inode *new_dir, struct dentry *new_dentry)
 602{
 603        struct super_block *sb = old_dir->i_sb;
 604        unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
 605        int err, is_hid;
 606
 607        mutex_lock(&MSDOS_SB(sb)->s_lock);
 608
 609        err = msdos_format_name(old_dentry->d_name.name,
 610                                old_dentry->d_name.len, old_msdos_name,
 611                                &MSDOS_SB(old_dir->i_sb)->options);
 612        if (err)
 613                goto out;
 614        err = msdos_format_name(new_dentry->d_name.name,
 615                                new_dentry->d_name.len, new_msdos_name,
 616                                &MSDOS_SB(new_dir->i_sb)->options);
 617        if (err)
 618                goto out;
 619
 620        is_hid =
 621             (new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');
 622
 623        err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
 624                              new_dir, new_msdos_name, new_dentry, is_hid);
 625out:
 626        mutex_unlock(&MSDOS_SB(sb)->s_lock);
 627        if (!err)
 628                err = fat_flush_inodes(sb, old_dir, new_dir);
 629        return err;
 630}
 631
 632static const struct inode_operations msdos_dir_inode_operations = {
 633        .create         = msdos_create,
 634        .lookup         = msdos_lookup,
 635        .unlink         = msdos_unlink,
 636        .mkdir          = msdos_mkdir,
 637        .rmdir          = msdos_rmdir,
 638        .rename         = msdos_rename,
 639        .setattr        = fat_setattr,
 640        .getattr        = fat_getattr,
 641};
 642
 643static void setup(struct super_block *sb)
 644{
 645        MSDOS_SB(sb)->dir_ops = &msdos_dir_inode_operations;
 646        sb->s_d_op = &msdos_dentry_operations;
 647        sb->s_flags |= MS_NOATIME;
 648}
 649
 650static int msdos_fill_super(struct super_block *sb, void *data, int silent)
 651{
 652        return fat_fill_super(sb, data, silent, 0, setup);
 653}
 654
 655static struct dentry *msdos_mount(struct file_system_type *fs_type,
 656                        int flags, const char *dev_name,
 657                        void *data)
 658{
 659        return mount_bdev(fs_type, flags, dev_name, data, msdos_fill_super);
 660}
 661
 662static struct file_system_type msdos_fs_type = {
 663        .owner          = THIS_MODULE,
 664        .name           = "msdos",
 665        .mount          = msdos_mount,
 666        .kill_sb        = kill_block_super,
 667        .fs_flags       = FS_REQUIRES_DEV,
 668};
 669MODULE_ALIAS_FS("msdos");
 670
 671static int __init init_msdos_fs(void)
 672{
 673        return register_filesystem(&msdos_fs_type);
 674}
 675
 676static void __exit exit_msdos_fs(void)
 677{
 678        unregister_filesystem(&msdos_fs_type);
 679}
 680
 681MODULE_LICENSE("GPL");
 682MODULE_AUTHOR("Werner Almesberger");
 683MODULE_DESCRIPTION("MS-DOS filesystem support");
 684
 685module_init(init_msdos_fs)
 686module_exit(exit_msdos_fs)
 687