fs/fat/namei_msdos.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/fs/msdos/namei.c
   4  *
   5  *  Written 1992,1993 by Werner Almesberger
   6  *  Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu>
   7  *  Rewritten for constant inumbers 1999 by Al Viro
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/iversion.h>
  12 #include "fat.h"
  13
  14 /* Characters that are undesirable in an MS-DOS file name */
  15 static unsigned char bad_chars[] = "*?<>|\"";
  16 static unsigned char bad_if_strict[] = "+=,; ";
  17
  18 /***** Formats an MS-DOS file name. Rejects invalid names. */
  19 static 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. */
 119 static 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  */
 151 static 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(dentry, 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  */
 167 static int msdos_cmp(const struct dentry *dentry,
 168                 unsigned int len, const char *str, const struct qstr *name)
 169 {
 170         struct fat_mount_options *options = &MSDOS_SB(dentry->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);
 181 out:
 182         return error;
 183
 184 old_compare:
 185         error = 1;
 186         if (name->len == len)
 187                 error = memcmp(name->name, str, len);
 188         goto out;
 189 }
 190
 191 static 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 */
 201 static 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). */
 227 static int msdos_add_entry(struct inode *dir, const unsigned char *name,
 228                            int is_dir, int is_hid, int cluster,
 229                            struct timespec64 *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         fat_truncate_time(dir, ts, S_CTIME|S_MTIME);
 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 */
 264 static int msdos_create(struct mnt_idmap *idmap, struct inode *dir,
 265                         struct dentry *dentry, umode_t mode, bool excl)
 266 {
 267         struct super_block *sb = dir->i_sb;
 268         struct inode *inode = NULL;
 269         struct fat_slot_info sinfo;
 270         struct timespec64 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(dir);
 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         fat_truncate_time(inode, &ts, S_ATIME|S_CTIME|S_MTIME);
 299         /* timestamp is already written, so mark_inode_dirty() is unneeded. */
 300
 301         d_instantiate(dentry, inode);
 302 out:
 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 */
 310 static int msdos_rmdir(struct inode *dir, struct dentry *dentry)
 311 {
 312         struct super_block *sb = dir->i_sb;
 313         struct inode *inode = d_inode(dentry);
 314         struct fat_slot_info sinfo;
 315         int err;
 316
 317         mutex_lock(&MSDOS_SB(sb)->s_lock);
 318         err = fat_dir_empty(inode);
 319         if (err)
 320                 goto out;
 321         err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
 322         if (err)
 323                 goto out;
 324
 325         err = fat_remove_entries(dir, &sinfo);  /* and releases bh */
 326         if (err)
 327                 goto out;
 328         drop_nlink(dir);
 329
 330         clear_nlink(inode);
 331         fat_truncate_time(inode, NULL, S_CTIME);
 332         fat_detach(inode);
 333 out:
 334         mutex_unlock(&MSDOS_SB(sb)->s_lock);
 335         if (!err)
 336                 err = fat_flush_inodes(sb, dir, inode);
 337
 338         return err;
 339 }
 340
 341 /***** Make a directory */
 342 static int msdos_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 343                        struct dentry *dentry, umode_t mode)
 344 {
 345         struct super_block *sb = dir->i_sb;
 346         struct fat_slot_info sinfo;
 347         struct inode *inode;
 348         unsigned char msdos_name[MSDOS_NAME];
 349         struct timespec64 ts;
 350         int err, is_hid, cluster;
 351
 352         mutex_lock(&MSDOS_SB(sb)->s_lock);
 353
 354         err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
 355                                 msdos_name, &MSDOS_SB(sb)->options);
 356         if (err)
 357                 goto out;
 358         is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
 359         /* foo vs .foo situation */
 360         if (!fat_scan(dir, msdos_name, &sinfo)) {
 361                 brelse(sinfo.bh);
 362                 err = -EINVAL;
 363                 goto out;
 364         }
 365
 366         ts = current_time(dir);
 367         cluster = fat_alloc_new_dir(dir, &ts);
 368         if (cluster < 0) {
 369                 err = cluster;
 370                 goto out;
 371         }
 372         err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
 373         if (err)
 374                 goto out_free;
 375         inc_nlink(dir);
 376
 377         inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
 378         brelse(sinfo.bh);
 379         if (IS_ERR(inode)) {
 380                 err = PTR_ERR(inode);
 381                 /* the directory was completed, just return a error */
 382                 goto out;
 383         }
 384         set_nlink(inode, 2);
 385         fat_truncate_time(inode, &ts, S_ATIME|S_CTIME|S_MTIME);
 386         /* timestamp is already written, so mark_inode_dirty() is unneeded. */
 387
 388         d_instantiate(dentry, inode);
 389
 390         mutex_unlock(&MSDOS_SB(sb)->s_lock);
 391         fat_flush_inodes(sb, dir, inode);
 392         return 0;
 393
 394 out_free:
 395         fat_free_clusters(dir, cluster);
 396 out:
 397         mutex_unlock(&MSDOS_SB(sb)->s_lock);
 398         return err;
 399 }
 400
 401 /***** Unlink a file */
 402 static int msdos_unlink(struct inode *dir, struct dentry *dentry)
 403 {
 404         struct inode *inode = d_inode(dentry);
 405         struct super_block *sb = inode->i_sb;
 406         struct fat_slot_info sinfo;
 407         int err;
 408
 409         mutex_lock(&MSDOS_SB(sb)->s_lock);
 410         err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
 411         if (err)
 412                 goto out;
 413
 414         err = fat_remove_entries(dir, &sinfo);  /* and releases bh */
 415         if (err)
 416                 goto out;
 417         clear_nlink(inode);
 418         fat_truncate_time(inode, NULL, S_CTIME);
 419         fat_detach(inode);
 420 out:
 421         mutex_unlock(&MSDOS_SB(sb)->s_lock);
 422         if (!err)
 423                 err = fat_flush_inodes(sb, dir, inode);
 424
 425         return err;
 426 }
 427
 428 static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
 429                            struct dentry *old_dentry,
 430                            struct inode *new_dir, unsigned char *new_name,
 431                            struct dentry *new_dentry, int is_hid)
 432 {
 433         struct buffer_head *dotdot_bh;
 434         struct msdos_dir_entry *dotdot_de;
 435         struct inode *old_inode, *new_inode;
 436         struct fat_slot_info old_sinfo, sinfo;
 437         struct timespec64 ts;
 438         loff_t new_i_pos;
 439         int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
 440
 441         old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
 442         old_inode = d_inode(old_dentry);
 443         new_inode = d_inode(new_dentry);
 444
 445         err = fat_scan(old_dir, old_name, &old_sinfo);
 446         if (err) {
 447                 err = -EIO;
 448                 goto out;
 449         }
 450
 451         is_dir = S_ISDIR(old_inode->i_mode);
 452         update_dotdot = (is_dir && old_dir != new_dir);
 453         if (update_dotdot) {
 454                 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de)) {
 455                         err = -EIO;
 456                         goto out;
 457                 }
 458         }
 459
 460         old_attrs = MSDOS_I(old_inode)->i_attrs;
 461         err = fat_scan(new_dir, new_name, &sinfo);
 462         if (!err) {
 463                 if (!new_inode) {
 464                         /* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
 465                         if (sinfo.de != old_sinfo.de) {
 466                                 err = -EINVAL;
 467                                 goto out;
 468                         }
 469                         if (is_hid)
 470                                 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
 471                         else
 472                                 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
 473                         if (IS_DIRSYNC(old_dir)) {
 474                                 err = fat_sync_inode(old_inode);
 475                                 if (err) {
 476                                         MSDOS_I(old_inode)->i_attrs = old_attrs;
 477                                         goto out;
 478                                 }
 479                         } else
 480                                 mark_inode_dirty(old_inode);
 481
 482                         inode_inc_iversion(old_dir);
 483                         fat_truncate_time(old_dir, NULL, S_CTIME|S_MTIME);
 484                         if (IS_DIRSYNC(old_dir))
 485                                 (void)fat_sync_inode(old_dir);
 486                         else
 487                                 mark_inode_dirty(old_dir);
 488                         goto out;
 489                 }
 490         }
 491
 492         ts = current_time(old_inode);
 493         if (new_inode) {
 494                 if (err)
 495                         goto out;
 496                 if (is_dir) {
 497                         err = fat_dir_empty(new_inode);
 498                         if (err)
 499                                 goto out;
 500                 }
 501                 new_i_pos = MSDOS_I(new_inode)->i_pos;
 502                 fat_detach(new_inode);
 503         } else {
 504                 err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
 505                                       &ts, &sinfo);
 506                 if (err)
 507                         goto out;
 508                 new_i_pos = sinfo.i_pos;
 509         }
 510         inode_inc_iversion(new_dir);
 511
 512         fat_detach(old_inode);
 513         fat_attach(old_inode, new_i_pos);
 514         if (is_hid)
 515                 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
 516         else
 517                 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
 518         if (IS_DIRSYNC(new_dir)) {
 519                 err = fat_sync_inode(old_inode);
 520                 if (err)
 521                         goto error_inode;
 522         } else
 523                 mark_inode_dirty(old_inode);
 524
 525         if (update_dotdot) {
 526                 fat_set_start(dotdot_de, MSDOS_I(new_dir)->i_logstart);
 527                 mark_buffer_dirty_inode(dotdot_bh, old_inode);
 528                 if (IS_DIRSYNC(new_dir)) {
 529                         err = sync_dirty_buffer(dotdot_bh);
 530                         if (err)
 531                                 goto error_dotdot;
 532                 }
 533                 drop_nlink(old_dir);
 534                 if (!new_inode)
 535                         inc_nlink(new_dir);
 536         }
 537
 538         err = fat_remove_entries(old_dir, &old_sinfo);  /* and releases bh */
 539         old_sinfo.bh = NULL;
 540         if (err)
 541                 goto error_dotdot;
 542         inode_inc_iversion(old_dir);
 543         fat_truncate_time(old_dir, &ts, S_CTIME|S_MTIME);
 544         if (IS_DIRSYNC(old_dir))
 545                 (void)fat_sync_inode(old_dir);
 546         else
 547                 mark_inode_dirty(old_dir);
 548
 549         if (new_inode) {
 550                 drop_nlink(new_inode);
 551                 if (is_dir)
 552                         drop_nlink(new_inode);
 553                 fat_truncate_time(new_inode, &ts, S_CTIME);
 554         }
 555 out:
 556         brelse(sinfo.bh);
 557         brelse(dotdot_bh);
 558         brelse(old_sinfo.bh);
 559         return err;
 560
 561 error_dotdot:
 562         /* data cluster is shared, serious corruption */
 563         corrupt = 1;
 564
 565         if (update_dotdot) {
 566                 fat_set_start(dotdot_de, MSDOS_I(old_dir)->i_logstart);
 567                 mark_buffer_dirty_inode(dotdot_bh, old_inode);
 568                 corrupt |= sync_dirty_buffer(dotdot_bh);
 569         }
 570 error_inode:
 571         fat_detach(old_inode);
 572         fat_attach(old_inode, old_sinfo.i_pos);
 573         MSDOS_I(old_inode)->i_attrs = old_attrs;
 574         if (new_inode) {
 575                 fat_attach(new_inode, new_i_pos);
 576                 if (corrupt)
 577                         corrupt |= fat_sync_inode(new_inode);
 578         } else {
 579                 /*
 580                  * If new entry was not sharing the data cluster, it
 581                  * shouldn't be serious corruption.
 582                  */
 583                 int err2 = fat_remove_entries(new_dir, &sinfo);
 584                 if (corrupt)
 585                         corrupt |= err2;
 586                 sinfo.bh = NULL;
 587         }
 588         if (corrupt < 0) {
 589                 fat_fs_error(new_dir->i_sb,
 590                              "%s: Filesystem corrupted (i_pos %lld)",
 591                              __func__, sinfo.i_pos);
 592         }
 593         goto out;
 594 }
 595
 596 /***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
 597 static int msdos_rename(struct mnt_idmap *idmap,
 598                         struct inode *old_dir, struct dentry *old_dentry,
 599                         struct inode *new_dir, struct dentry *new_dentry,
 600                         unsigned int flags)
 601 {
 602         struct super_block *sb = old_dir->i_sb;
 603         unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
 604         int err, is_hid;
 605
 606         if (flags & ~RENAME_NOREPLACE)
 607                 return -EINVAL;
 608
 609         mutex_lock(&MSDOS_SB(sb)->s_lock);
 610
 611         err = msdos_format_name(old_dentry->d_name.name,
 612                                 old_dentry->d_name.len, old_msdos_name,
 613                                 &MSDOS_SB(old_dir->i_sb)->options);
 614         if (err)
 615                 goto out;
 616         err = msdos_format_name(new_dentry->d_name.name,
 617                                 new_dentry->d_name.len, new_msdos_name,
 618                                 &MSDOS_SB(new_dir->i_sb)->options);
 619         if (err)
 620                 goto out;
 621
 622         is_hid =
 623              (new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');
 624
 625         err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
 626                               new_dir, new_msdos_name, new_dentry, is_hid);
 627 out:
 628         mutex_unlock(&MSDOS_SB(sb)->s_lock);
 629         if (!err)
 630                 err = fat_flush_inodes(sb, old_dir, new_dir);
 631         return err;
 632 }
 633
 634 static const struct inode_operations msdos_dir_inode_operations = {
 635         .create         = msdos_create,
 636         .lookup         = msdos_lookup,
 637         .unlink         = msdos_unlink,
 638         .mkdir          = msdos_mkdir,
 639         .rmdir          = msdos_rmdir,
 640         .rename         = msdos_rename,
 641         .setattr        = fat_setattr,
 642         .getattr        = fat_getattr,
 643         .update_time    = fat_update_time,
 644 };
 645
 646 static void setup(struct super_block *sb)
 647 {
 648         MSDOS_SB(sb)->dir_ops = &msdos_dir_inode_operations;
 649         sb->s_d_op = &msdos_dentry_operations;
 650         sb->s_flags |= SB_NOATIME;
 651 }
 652
 653 static int msdos_fill_super(struct super_block *sb, struct fs_context *fc)
 654 {
 655         return fat_fill_super(sb, fc, setup);
 656 }
 657
 658 static int msdos_get_tree(struct fs_context *fc)
 659 {
 660         return get_tree_bdev(fc, msdos_fill_super);
 661 }
 662
 663 static int msdos_parse_param(struct fs_context *fc, struct fs_parameter *param)
 664 {
 665         return fat_parse_param(fc, param, false);
 666 }
 667
 668 static const struct fs_context_operations msdos_context_ops = {
 669         .parse_param    = msdos_parse_param,
 670         .get_tree       = msdos_get_tree,
 671         .reconfigure    = fat_reconfigure,
 672         .free           = fat_free_fc,
 673 };
 674
 675 static int msdos_init_fs_context(struct fs_context *fc)
 676 {
 677         int err;
 678
 679         /* Initialize with is_vfat == false */
 680         err = fat_init_fs_context(fc, false);
 681         if (err)
 682                 return err;
 683
 684         fc->ops = &msdos_context_ops;
 685         return 0;
 686 }
 687
 688 static struct file_system_type msdos_fs_type = {
 689         .owner          = THIS_MODULE,
 690         .name           = "msdos",
 691         .kill_sb        = kill_block_super,
 692         .fs_flags       = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
 693         .init_fs_context = msdos_init_fs_context,
 694         .parameters     = fat_param_spec,
 695 };
 696 MODULE_ALIAS_FS("msdos");
 697
 698 static int __init init_msdos_fs(void)
 699 {
 700         return register_filesystem(&msdos_fs_type);
 701 }
 702
 703 static void __exit exit_msdos_fs(void)
 704 {
 705         unregister_filesystem(&msdos_fs_type);
 706 }
 707
 708 MODULE_LICENSE("GPL");
 709 MODULE_AUTHOR("Werner Almesberger");
 710 MODULE_DESCRIPTION("MS-DOS filesystem support");
 711
 712 module_init(init_msdos_fs)
 713 module_exit(exit_msdos_fs)