fs/fat/namei_msdos.c

   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/iversion.h>
  11 #include "fat.h"
  12
  13 /* Characters that are undesirable in an MS-DOS file name */
  14 static unsigned char bad_chars[] = "*?<>|\"";
  15 static unsigned char bad_if_strict[] = "+=,; ";
  16
  17 /***** Formats an MS-DOS file name. Rejects invalid names. */
  18 static int msdos_format_name(const unsigned char *name, int len,
  19                              unsigned char *res, struct fat_mount_options *opts)
  20         /*
  21          * name is the proposed name, len is its length, res is
  22          * the resulting name, opts->name_check is either (r)elaxed,
  23          * (n)ormal or (s)trict, opts->dotsOK allows dots at the
  24          * beginning of name (for hidden files)
  25          */
  26 {
  27         unsigned char *walk;
  28         unsigned char c;
  29         int space;
  30
  31         if (name[0] == '.') {   /* dotfile because . and .. already done */
  32                 if (opts->dotsOK) {
  33                         /* Get rid of dot - test for it elsewhere */
  34                         name++;
  35                         len--;
  36                 } else
  37                         return -EINVAL;
  38         }
  39         /*
  40          * disallow names that _really_ start with a dot
  41          */
  42         space = 1;
  43         c = 0;
  44         for (walk = res; len && walk - res < 8; walk++) {
  45                 c = *name++;
  46                 len--;
  47                 if (opts->name_check != 'r' && strchr(bad_chars, c))
  48                         return -EINVAL;
  49                 if (opts->name_check == 's' && strchr(bad_if_strict, c))
  50                         return -EINVAL;
  51                 if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
  52                         return -EINVAL;
  53                 if (c < ' ' || c == ':' || c == '\\')
  54                         return -EINVAL;
  55         /*
  56          * 0xE5 is legal as a first character, but we must substitute
  57          * 0x05 because 0xE5 marks deleted files.  Yes, DOS really
  58          * does this.
  59          * It seems that Microsoft hacked DOS to support non-US
  60          * characters after the 0xE5 character was already in use to
  61          * mark deleted files.
  62          */
  63                 if ((res == walk) && (c == 0xE5))
  64                         c = 0x05;
  65                 if (c == '.')
  66                         break;
  67                 space = (c == ' ');
  68                 *walk = (!opts->nocase && c >= 'a' && c <= 'z') ? c - 32 : c;
  69         }
  70         if (space)
  71                 return -EINVAL;
  72         if (opts->name_check == 's' && len && c != '.') {
  73                 c = *name++;
  74                 len--;
  75                 if (c != '.')
  76                         return -EINVAL;
  77         }
  78         while (c != '.' && len--)
  79                 c = *name++;
  80         if (c == '.') {
  81                 while (walk - res < 8)
  82                         *walk++ = ' ';
  83                 while (len > 0 && walk - res < MSDOS_NAME) {
  84                         c = *name++;
  85                         len--;
  86                         if (opts->name_check != 'r' && strchr(bad_chars, c))
  87                                 return -EINVAL;
  88                         if (opts->name_check == 's' &&
  89                             strchr(bad_if_strict, c))
  90                                 return -EINVAL;
  91                         if (c < ' ' || c == ':' || c == '\\')
  92                                 return -EINVAL;
  93                         if (c == '.') {
  94                                 if (opts->name_check == 's')
  95                                         return -EINVAL;
  96                                 break;
  97                         }
  98                         if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
  99                                 return -EINVAL;
 100                         space = c == ' ';
 101                         if (!opts->nocase && c >= 'a' && c <= 'z')
 102                                 *walk++ = c - 32;
 103                         else
 104                                 *walk++ = c;
 105                 }
 106                 if (space)
 107                         return -EINVAL;
 108                 if (opts->name_check == 's' && len)
 109                         return -EINVAL;
 110         }
 111         while (walk - res < MSDOS_NAME)
 112                 *walk++ = ' ';
 113
 114         return 0;
 115 }
 116
 117 /***** Locates a directory entry.  Uses unformatted name. */
 118 static int msdos_find(struct inode *dir, const unsigned char *name, int len,
 119                       struct fat_slot_info *sinfo)
 120 {
 121         struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
 122         unsigned char msdos_name[MSDOS_NAME];
 123         int err;
 124
 125         err = msdos_format_name(name, len, msdos_name, &sbi->options);
 126         if (err)
 127                 return -ENOENT;
 128
 129         err = fat_scan(dir, msdos_name, sinfo);
 130         if (!err && sbi->options.dotsOK) {
 131                 if (name[0] == '.') {
 132                         if (!(sinfo->de->attr & ATTR_HIDDEN))
 133                                 err = -ENOENT;
 134                 } else {
 135                         if (sinfo->de->attr & ATTR_HIDDEN)
 136                                 err = -ENOENT;
 137                 }
 138                 if (err)
 139                         brelse(sinfo->bh);
 140         }
 141         return err;
 142 }
 143
 144 /*
 145  * Compute the hash for the msdos name corresponding to the dentry.
 146  * Note: if the name is invalid, we leave the hash code unchanged so
 147  * that the existing dentry can be used. The msdos fs routines will
 148  * return ENOENT or EINVAL as appropriate.
 149  */
 150 static int msdos_hash(const struct dentry *dentry, struct qstr *qstr)
 151 {
 152         struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
 153         unsigned char msdos_name[MSDOS_NAME];
 154         int error;
 155
 156         error = msdos_format_name(qstr->name, qstr->len, msdos_name, options);
 157         if (!error)
 158                 qstr->hash = full_name_hash(dentry, msdos_name, MSDOS_NAME);
 159         return 0;
 160 }
 161
 162 /*
 163  * Compare two msdos names. If either of the names are invalid,
 164  * we fall back to doing the standard name comparison.
 165  */
 166 static int msdos_cmp(const struct dentry *dentry,
 167                 unsigned int len, const char *str, const struct qstr *name)
 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(name->name, name->len, a_msdos_name, options);
 174         if (error)
 175                 goto old_compare;
 176         error = msdos_format_name(str, len, b_msdos_name, options);
 177         if (error)
 178                 goto old_compare;
 179         error = memcmp(a_msdos_name, b_msdos_name, MSDOS_NAME);
 180 out:
 181         return error;
 182
 183 old_compare:
 184         error = 1;
 185         if (name->len == len)
 186                 error = memcmp(name->name, str, len);
 187         goto out;
 188 }
 189
 190 static 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 */
 200 static struct dentry *msdos_lookup(struct inode *dir, struct dentry *dentry,
 201                                    unsigned int flags)
 202 {
 203         struct super_block *sb = dir->i_sb;
 204         struct fat_slot_info sinfo;
 205         struct inode *inode;
 206         int err;
 207
 208         mutex_lock(&MSDOS_SB(sb)->s_lock);
 209         err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
 210         switch (err) {
 211         case -ENOENT:
 212                 inode = NULL;
 213                 break;
 214         case 0:
 215                 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
 216                 brelse(sinfo.bh);
 217                 break;
 218         default:
 219                 inode = ERR_PTR(err);
 220         }
 221         mutex_unlock(&MSDOS_SB(sb)->s_lock);
 222         return d_splice_alias(inode, dentry);
 223 }
 224
 225 /***** Creates a directory entry (name is already formatted). */
 226 static int msdos_add_entry(struct inode *dir, const unsigned char *name,
 227                            int is_dir, int is_hid, int cluster,
 228                            struct timespec64 *ts, struct fat_slot_info *sinfo)
 229 {
 230         struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
 231         struct msdos_dir_entry de;
 232         __le16 time, date;
 233         int err;
 234
 235         memcpy(de.name, name, MSDOS_NAME);
 236         de.attr = is_dir ? ATTR_DIR : ATTR_ARCH;
 237         if (is_hid)
 238                 de.attr |= ATTR_HIDDEN;
 239         de.lcase = 0;
 240         fat_time_unix2fat(sbi, ts, &time, &date, NULL);
 241         de.cdate = de.adate = 0;
 242         de.ctime = 0;
 243         de.ctime_cs = 0;
 244         de.time = time;
 245         de.date = date;
 246         fat_set_start(&de, cluster);
 247         de.size = 0;
 248
 249         err = fat_add_entries(dir, &de, 1, sinfo);
 250         if (err)
 251                 return err;
 252
 253         dir->i_ctime = dir->i_mtime = *ts;
 254         if (IS_DIRSYNC(dir))
 255                 (void)fat_sync_inode(dir);
 256         else
 257                 mark_inode_dirty(dir);
 258
 259         return 0;
 260 }
 261
 262 /***** Create a file */
 263 static int msdos_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 264                         bool excl)
 265 {
 266         struct super_block *sb = dir->i_sb;
 267         struct inode *inode = NULL;
 268         struct fat_slot_info sinfo;
 269         struct timespec64 ts;
 270         unsigned char msdos_name[MSDOS_NAME];
 271         int err, is_hid;
 272
 273         mutex_lock(&MSDOS_SB(sb)->s_lock);
 274
 275         err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
 276                                 msdos_name, &MSDOS_SB(sb)->options);
 277         if (err)
 278                 goto out;
 279         is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
 280         /* Have to do it due to foo vs. .foo conflicts */
 281         if (!fat_scan(dir, msdos_name, &sinfo)) {
 282                 brelse(sinfo.bh);
 283                 err = -EINVAL;
 284                 goto out;
 285         }
 286
 287         ts = current_time(dir);
 288         err = msdos_add_entry(dir, msdos_name, 0, is_hid, 0, &ts, &sinfo);
 289         if (err)
 290                 goto out;
 291         inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
 292         brelse(sinfo.bh);
 293         if (IS_ERR(inode)) {
 294                 err = PTR_ERR(inode);
 295                 goto out;
 296         }
 297         inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
 298         /* timestamp is already written, so mark_inode_dirty() is unneeded. */
 299
 300         d_instantiate(dentry, inode);
 301 out:
 302         mutex_unlock(&MSDOS_SB(sb)->s_lock);
 303         if (!err)
 304                 err = fat_flush_inodes(sb, dir, inode);
 305         return err;
 306 }
 307
 308 /***** Remove a directory */
 309 static int msdos_rmdir(struct inode *dir, struct dentry *dentry)
 310 {
 311         struct super_block *sb = dir->i_sb;
 312         struct inode *inode = d_inode(dentry);
 313         struct fat_slot_info sinfo;
 314         int err;
 315
 316         mutex_lock(&MSDOS_SB(sb)->s_lock);
 317         err = fat_dir_empty(inode);
 318         if (err)
 319                 goto out;
 320         err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
 321         if (err)
 322                 goto out;
 323
 324         err = fat_remove_entries(dir, &sinfo);  /* and releases bh */
 325         if (err)
 326                 goto out;
 327         drop_nlink(dir);
 328
 329         clear_nlink(inode);
 330         inode->i_ctime = current_time(inode);
 331         fat_detach(inode);
 332 out:
 333         mutex_unlock(&MSDOS_SB(sb)->s_lock);
 334         if (!err)
 335                 err = fat_flush_inodes(sb, dir, inode);
 336
 337         return err;
 338 }
 339
 340 /***** Make a directory */
 341 static int msdos_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 342 {
 343         struct super_block *sb = dir->i_sb;
 344         struct fat_slot_info sinfo;
 345         struct inode *inode;
 346         unsigned char msdos_name[MSDOS_NAME];
 347         struct timespec64 ts;
 348         int err, is_hid, cluster;
 349
 350         mutex_lock(&MSDOS_SB(sb)->s_lock);
 351
 352         err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
 353                                 msdos_name, &MSDOS_SB(sb)->options);
 354         if (err)
 355                 goto out;
 356         is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
 357         /* foo vs .foo situation */
 358         if (!fat_scan(dir, msdos_name, &sinfo)) {
 359                 brelse(sinfo.bh);
 360                 err = -EINVAL;
 361                 goto out;
 362         }
 363
 364         ts = current_time(dir);
 365         cluster = fat_alloc_new_dir(dir, &ts);
 366         if (cluster < 0) {
 367                 err = cluster;
 368                 goto out;
 369         }
 370         err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
 371         if (err)
 372                 goto out_free;
 373         inc_nlink(dir);
 374
 375         inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
 376         brelse(sinfo.bh);
 377         if (IS_ERR(inode)) {
 378                 err = PTR_ERR(inode);
 379                 /* the directory was completed, just return a error */
 380                 goto out;
 381         }
 382         set_nlink(inode, 2);
 383         inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
 384         /* timestamp is already written, so mark_inode_dirty() is unneeded. */
 385
 386         d_instantiate(dentry, inode);
 387
 388         mutex_unlock(&MSDOS_SB(sb)->s_lock);
 389         fat_flush_inodes(sb, dir, inode);
 390         return 0;
 391
 392 out_free:
 393         fat_free_clusters(dir, cluster);
 394 out:
 395         mutex_unlock(&MSDOS_SB(sb)->s_lock);
 396         return err;
 397 }
 398
 399 /***** Unlink a file */
 400 static int msdos_unlink(struct inode *dir, struct dentry *dentry)
 401 {
 402         struct inode *inode = d_inode(dentry);
 403         struct super_block *sb = inode->i_sb;
 404         struct fat_slot_info sinfo;
 405         int err;
 406
 407         mutex_lock(&MSDOS_SB(sb)->s_lock);
 408         err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
 409         if (err)
 410                 goto out;
 411
 412         err = fat_remove_entries(dir, &sinfo);  /* and releases bh */
 413         if (err)
 414                 goto out;
 415         clear_nlink(inode);
 416         inode->i_ctime = current_time(inode);
 417         fat_detach(inode);
 418 out:
 419         mutex_unlock(&MSDOS_SB(sb)->s_lock);
 420         if (!err)
 421                 err = fat_flush_inodes(sb, dir, inode);
 422
 423         return err;
 424 }
 425
 426 static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
 427                            struct dentry *old_dentry,
 428                            struct inode *new_dir, unsigned char *new_name,
 429                            struct dentry *new_dentry, int is_hid)
 430 {
 431         struct buffer_head *dotdot_bh;
 432         struct msdos_dir_entry *dotdot_de;
 433         struct inode *old_inode, *new_inode;
 434         struct fat_slot_info old_sinfo, sinfo;
 435         struct timespec64 ts;
 436         loff_t new_i_pos;
 437         int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
 438
 439         old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
 440         old_inode = d_inode(old_dentry);
 441         new_inode = d_inode(new_dentry);
 442
 443         err = fat_scan(old_dir, old_name, &old_sinfo);
 444         if (err) {
 445                 err = -EIO;
 446                 goto out;
 447         }
 448
 449         is_dir = S_ISDIR(old_inode->i_mode);
 450         update_dotdot = (is_dir && old_dir != new_dir);
 451         if (update_dotdot) {
 452                 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de)) {
 453                         err = -EIO;
 454                         goto out;
 455                 }
 456         }
 457
 458         old_attrs = MSDOS_I(old_inode)->i_attrs;
 459         err = fat_scan(new_dir, new_name, &sinfo);
 460         if (!err) {
 461                 if (!new_inode) {
 462                         /* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
 463                         if (sinfo.de != old_sinfo.de) {
 464                                 err = -EINVAL;
 465                                 goto out;
 466                         }
 467                         if (is_hid)
 468                                 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
 469                         else
 470                                 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
 471                         if (IS_DIRSYNC(old_dir)) {
 472                                 err = fat_sync_inode(old_inode);
 473                                 if (err) {
 474                                         MSDOS_I(old_inode)->i_attrs = old_attrs;
 475                                         goto out;
 476                                 }
 477                         } else
 478                                 mark_inode_dirty(old_inode);
 479
 480                         inode_inc_iversion(old_dir);
 481                         old_dir->i_ctime = old_dir->i_mtime = current_time(old_dir);
 482                         if (IS_DIRSYNC(old_dir))
 483                                 (void)fat_sync_inode(old_dir);
 484                         else
 485                                 mark_inode_dirty(old_dir);
 486                         goto out;
 487                 }
 488         }
 489
 490         ts = current_time(old_inode);
 491         if (new_inode) {
 492                 if (err)
 493                         goto out;
 494                 if (is_dir) {
 495                         err = fat_dir_empty(new_inode);
 496                         if (err)
 497                                 goto out;
 498                 }
 499                 new_i_pos = MSDOS_I(new_inode)->i_pos;
 500                 fat_detach(new_inode);
 501         } else {
 502                 err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
 503                                       &ts, &sinfo);
 504                 if (err)
 505                         goto out;
 506                 new_i_pos = sinfo.i_pos;
 507         }
 508         inode_inc_iversion(new_dir);
 509
 510         fat_detach(old_inode);
 511         fat_attach(old_inode, new_i_pos);
 512         if (is_hid)
 513                 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
 514         else
 515                 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
 516         if (IS_DIRSYNC(new_dir)) {
 517                 err = fat_sync_inode(old_inode);
 518                 if (err)
 519                         goto error_inode;
 520         } else
 521                 mark_inode_dirty(old_inode);
 522
 523         if (update_dotdot) {
 524                 fat_set_start(dotdot_de, MSDOS_I(new_dir)->i_logstart);
 525                 mark_buffer_dirty_inode(dotdot_bh, old_inode);
 526                 if (IS_DIRSYNC(new_dir)) {
 527                         err = sync_dirty_buffer(dotdot_bh);
 528                         if (err)
 529                                 goto error_dotdot;
 530                 }
 531                 drop_nlink(old_dir);
 532                 if (!new_inode)
 533                         inc_nlink(new_dir);
 534         }
 535
 536         err = fat_remove_entries(old_dir, &old_sinfo);  /* and releases bh */
 537         old_sinfo.bh = NULL;
 538         if (err)
 539                 goto error_dotdot;
 540         inode_inc_iversion(old_dir);
 541         old_dir->i_ctime = old_dir->i_mtime = ts;
 542         if (IS_DIRSYNC(old_dir))
 543                 (void)fat_sync_inode(old_dir);
 544         else
 545                 mark_inode_dirty(old_dir);
 546
 547         if (new_inode) {
 548                 drop_nlink(new_inode);
 549                 if (is_dir)
 550                         drop_nlink(new_inode);
 551                 new_inode->i_ctime = ts;
 552         }
 553 out:
 554         brelse(sinfo.bh);
 555         brelse(dotdot_bh);
 556         brelse(old_sinfo.bh);
 557         return err;
 558
 559 error_dotdot:
 560         /* data cluster is shared, serious corruption */
 561         corrupt = 1;
 562
 563         if (update_dotdot) {
 564                 fat_set_start(dotdot_de, MSDOS_I(old_dir)->i_logstart);
 565                 mark_buffer_dirty_inode(dotdot_bh, old_inode);
 566                 corrupt |= sync_dirty_buffer(dotdot_bh);
 567         }
 568 error_inode:
 569         fat_detach(old_inode);
 570         fat_attach(old_inode, old_sinfo.i_pos);
 571         MSDOS_I(old_inode)->i_attrs = old_attrs;
 572         if (new_inode) {
 573                 fat_attach(new_inode, new_i_pos);
 574                 if (corrupt)
 575                         corrupt |= fat_sync_inode(new_inode);
 576         } else {
 577                 /*
 578                  * If new entry was not sharing the data cluster, it
 579                  * shouldn't be serious corruption.
 580                  */
 581                 int err2 = fat_remove_entries(new_dir, &sinfo);
 582                 if (corrupt)
 583                         corrupt |= err2;
 584                 sinfo.bh = NULL;
 585         }
 586         if (corrupt < 0) {
 587                 fat_fs_error(new_dir->i_sb,
 588                              "%s: Filesystem corrupted (i_pos %lld)",
 589                              __func__, sinfo.i_pos);
 590         }
 591         goto out;
 592 }
 593
 594 /***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
 595 static int msdos_rename(struct inode *old_dir, struct dentry *old_dentry,
 596                         struct inode *new_dir, struct dentry *new_dentry,
 597                         unsigned int flags)
 598 {
 599         struct super_block *sb = old_dir->i_sb;
 600         unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
 601         int err, is_hid;
 602
 603         if (flags & ~RENAME_NOREPLACE)
 604                 return -EINVAL;
 605
 606         mutex_lock(&MSDOS_SB(sb)->s_lock);
 607
 608         err = msdos_format_name(old_dentry->d_name.name,
 609                                 old_dentry->d_name.len, old_msdos_name,
 610                                 &MSDOS_SB(old_dir->i_sb)->options);
 611         if (err)
 612                 goto out;
 613         err = msdos_format_name(new_dentry->d_name.name,
 614                                 new_dentry->d_name.len, new_msdos_name,
 615                                 &MSDOS_SB(new_dir->i_sb)->options);
 616         if (err)
 617                 goto out;
 618
 619         is_hid =
 620              (new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');
 621
 622         err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
 623                               new_dir, new_msdos_name, new_dentry, is_hid);
 624 out:
 625         mutex_unlock(&MSDOS_SB(sb)->s_lock);
 626         if (!err)
 627                 err = fat_flush_inodes(sb, old_dir, new_dir);
 628         return err;
 629 }
 630
 631 static const struct inode_operations msdos_dir_inode_operations = {
 632         .create         = msdos_create,
 633         .lookup         = msdos_lookup,
 634         .unlink         = msdos_unlink,
 635         .mkdir          = msdos_mkdir,
 636         .rmdir          = msdos_rmdir,
 637         .rename         = msdos_rename,
 638         .setattr        = fat_setattr,
 639         .getattr        = fat_getattr,
 640 };
 641
 642 static void setup(struct super_block *sb)
 643 {
 644         MSDOS_SB(sb)->dir_ops = &msdos_dir_inode_operations;
 645         sb->s_d_op = &msdos_dentry_operations;
 646         sb->s_flags |= SB_NOATIME;
 647 }
 648
 649 static int msdos_fill_super(struct super_block *sb, void *data, int silent)
 650 {
 651         return fat_fill_super(sb, data, silent, 0, setup);
 652 }
 653
 654 static struct dentry *msdos_mount(struct file_system_type *fs_type,
 655                         int flags, const char *dev_name,
 656                         void *data)
 657 {
 658         return mount_bdev(fs_type, flags, dev_name, data, msdos_fill_super);
 659 }
 660
 661 static struct file_system_type msdos_fs_type = {
 662         .owner          = THIS_MODULE,
 663         .name           = "msdos",
 664         .mount          = msdos_mount,
 665         .kill_sb        = kill_block_super,
 666         .fs_flags       = FS_REQUIRES_DEV,
 667 };
 668 MODULE_ALIAS_FS("msdos");
 669
 670 static int __init init_msdos_fs(void)
 671 {
 672         return register_filesystem(&msdos_fs_type);
 673 }
 674
 675 static void __exit exit_msdos_fs(void)
 676 {
 677         unregister_filesystem(&msdos_fs_type);
 678 }
 679
 680 MODULE_LICENSE("GPL");
 681 MODULE_AUTHOR("Werner Almesberger");
 682 MODULE_DESCRIPTION("MS-DOS filesystem support");
 683
 684 module_init(init_msdos_fs)
 685 module_exit(exit_msdos_fs)