fs/fat/inode.c

   1 /*
   2  *  linux/fs/fat/inode.c
   3  *
   4  *  Written 1992,1993 by Werner Almesberger
   5  *  VFAT extensions by Gordon Chaffee, merged with msdos fs by Henrik Storner
   6  *  Rewritten for the constant inumbers support by Al Viro
   7  *
   8  *  Fixes:
   9  *
  10  *      Max Cohan: Fixed invalid FSINFO offset when info_sector is 0
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/pagemap.h>
  15 #include <linux/mpage.h>
  16 #include <linux/vfs.h>
  17 #include <linux/seq_file.h>
  18 #include <linux/parser.h>
  19 #include <linux/uio.h>
  20 #include <linux/blkdev.h>
  21 #include <linux/backing-dev.h>
  22 #include <asm/unaligned.h>
  23 #include <linux/iversion.h>
  24 #include "fat.h"
  25
  26 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET
  27 /* if user don't select VFAT, this is undefined. */
  28 #define CONFIG_FAT_DEFAULT_IOCHARSET    ""
  29 #endif
  30
  31 #define KB_IN_SECTORS 2
  32
  33 /*
  34  * A deserialized copy of the on-disk structure laid out in struct
  35  * fat_boot_sector.
  36  */
  37 struct fat_bios_param_block {
  38         u16     fat_sector_size;
  39         u8      fat_sec_per_clus;
  40         u16     fat_reserved;
  41         u8      fat_fats;
  42         u16     fat_dir_entries;
  43         u16     fat_sectors;
  44         u16     fat_fat_length;
  45         u32     fat_total_sect;
  46
  47         u8      fat16_state;
  48         u32     fat16_vol_id;
  49
  50         u32     fat32_length;
  51         u32     fat32_root_cluster;
  52         u16     fat32_info_sector;
  53         u8      fat32_state;
  54         u32     fat32_vol_id;
  55 };
  56
  57 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
  58 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
  59
  60 static struct fat_floppy_defaults {
  61         unsigned nr_sectors;
  62         unsigned sec_per_clus;
  63         unsigned dir_entries;
  64         unsigned media;
  65         unsigned fat_length;
  66 } floppy_defaults[] = {
  67 {
  68         .nr_sectors = 160 * KB_IN_SECTORS,
  69         .sec_per_clus = 1,
  70         .dir_entries = 64,
  71         .media = 0xFE,
  72         .fat_length = 1,
  73 },
  74 {
  75         .nr_sectors = 180 * KB_IN_SECTORS,
  76         .sec_per_clus = 1,
  77         .dir_entries = 64,
  78         .media = 0xFC,
  79         .fat_length = 2,
  80 },
  81 {
  82         .nr_sectors = 320 * KB_IN_SECTORS,
  83         .sec_per_clus = 2,
  84         .dir_entries = 112,
  85         .media = 0xFF,
  86         .fat_length = 1,
  87 },
  88 {
  89         .nr_sectors = 360 * KB_IN_SECTORS,
  90         .sec_per_clus = 2,
  91         .dir_entries = 112,
  92         .media = 0xFD,
  93         .fat_length = 2,
  94 },
  95 };
  96
  97 int fat_add_cluster(struct inode *inode)
  98 {
  99         int err, cluster;
 100
 101         err = fat_alloc_clusters(inode, &cluster, 1);
 102         if (err)
 103                 return err;
 104         /* FIXME: this cluster should be added after data of this
 105          * cluster is writed */
 106         err = fat_chain_add(inode, cluster, 1);
 107         if (err)
 108                 fat_free_clusters(inode, cluster);
 109         return err;
 110 }
 111
 112 static inline int __fat_get_block(struct inode *inode, sector_t iblock,
 113                                   unsigned long *max_blocks,
 114                                   struct buffer_head *bh_result, int create)
 115 {
 116         struct super_block *sb = inode->i_sb;
 117         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 118         unsigned long mapped_blocks;
 119         sector_t phys, last_block;
 120         int err, offset;
 121
 122         err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create, false);
 123         if (err)
 124                 return err;
 125         if (phys) {
 126                 map_bh(bh_result, sb, phys);
 127                 *max_blocks = min(mapped_blocks, *max_blocks);
 128                 return 0;
 129         }
 130         if (!create)
 131                 return 0;
 132
 133         if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
 134                 fat_fs_error(sb, "corrupted file size (i_pos %lld, %lld)",
 135                         MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
 136                 return -EIO;
 137         }
 138
 139         last_block = inode->i_blocks >> (sb->s_blocksize_bits - 9);
 140         offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
 141         /*
 142          * allocate a cluster according to the following.
 143          * 1) no more available blocks
 144          * 2) not part of fallocate region
 145          */
 146         if (!offset && !(iblock < last_block)) {
 147                 /* TODO: multiple cluster allocation would be desirable. */
 148                 err = fat_add_cluster(inode);
 149                 if (err)
 150                         return err;
 151         }
 152         /* available blocks on this cluster */
 153         mapped_blocks = sbi->sec_per_clus - offset;
 154
 155         *max_blocks = min(mapped_blocks, *max_blocks);
 156         MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
 157
 158         err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create, false);
 159         if (err)
 160                 return err;
 161         if (!phys) {
 162                 fat_fs_error(sb,
 163                              "invalid FAT chain (i_pos %lld, last_block %llu)",
 164                              MSDOS_I(inode)->i_pos,
 165                              (unsigned long long)last_block);
 166                 return -EIO;
 167         }
 168
 169         BUG_ON(*max_blocks != mapped_blocks);
 170         set_buffer_new(bh_result);
 171         map_bh(bh_result, sb, phys);
 172
 173         return 0;
 174 }
 175
 176 static int fat_get_block(struct inode *inode, sector_t iblock,
 177                          struct buffer_head *bh_result, int create)
 178 {
 179         struct super_block *sb = inode->i_sb;
 180         unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
 181         int err;
 182
 183         err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create);
 184         if (err)
 185                 return err;
 186         bh_result->b_size = max_blocks << sb->s_blocksize_bits;
 187         return 0;
 188 }
 189
 190 static int fat_writepage(struct page *page, struct writeback_control *wbc)
 191 {
 192         return block_write_full_page(page, fat_get_block, wbc);
 193 }
 194
 195 static int fat_writepages(struct address_space *mapping,
 196                           struct writeback_control *wbc)
 197 {
 198         return mpage_writepages(mapping, wbc, fat_get_block);
 199 }
 200
 201 static int fat_readpage(struct file *file, struct page *page)
 202 {
 203         return mpage_readpage(page, fat_get_block);
 204 }
 205
 206 static int fat_readpages(struct file *file, struct address_space *mapping,
 207                          struct list_head *pages, unsigned nr_pages)
 208 {
 209         return mpage_readpages(mapping, pages, nr_pages, fat_get_block);
 210 }
 211
 212 static void fat_write_failed(struct address_space *mapping, loff_t to)
 213 {
 214         struct inode *inode = mapping->host;
 215
 216         if (to > inode->i_size) {
 217                 truncate_pagecache(inode, inode->i_size);
 218                 fat_truncate_blocks(inode, inode->i_size);
 219         }
 220 }
 221
 222 static int fat_write_begin(struct file *file, struct address_space *mapping,
 223                         loff_t pos, unsigned len, unsigned flags,
 224                         struct page **pagep, void **fsdata)
 225 {
 226         int err;
 227
 228         *pagep = NULL;
 229         err = cont_write_begin(file, mapping, pos, len, flags,
 230                                 pagep, fsdata, fat_get_block,
 231                                 &MSDOS_I(mapping->host)->mmu_private);
 232         if (err < 0)
 233                 fat_write_failed(mapping, pos + len);
 234         return err;
 235 }
 236
 237 static int fat_write_end(struct file *file, struct address_space *mapping,
 238                         loff_t pos, unsigned len, unsigned copied,
 239                         struct page *pagep, void *fsdata)
 240 {
 241         struct inode *inode = mapping->host;
 242         int err;
 243         err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
 244         if (err < len)
 245                 fat_write_failed(mapping, pos + len);
 246         if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
 247                 inode->i_mtime = inode->i_ctime = current_time(inode);
 248                 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
 249                 mark_inode_dirty(inode);
 250         }
 251         return err;
 252 }
 253
 254 static ssize_t fat_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 255 {
 256         struct file *file = iocb->ki_filp;
 257         struct address_space *mapping = file->f_mapping;
 258         struct inode *inode = mapping->host;
 259         size_t count = iov_iter_count(iter);
 260         loff_t offset = iocb->ki_pos;
 261         ssize_t ret;
 262
 263         if (iov_iter_rw(iter) == WRITE) {
 264                 /*
 265                  * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
 266                  * so we need to update the ->mmu_private to block boundary.
 267                  *
 268                  * But we must fill the remaining area or hole by nul for
 269                  * updating ->mmu_private.
 270                  *
 271                  * Return 0, and fallback to normal buffered write.
 272                  */
 273                 loff_t size = offset + count;
 274                 if (MSDOS_I(inode)->mmu_private < size)
 275                         return 0;
 276         }
 277
 278         /*
 279          * FAT need to use the DIO_LOCKING for avoiding the race
 280          * condition of fat_get_block() and ->truncate().
 281          */
 282         ret = blockdev_direct_IO(iocb, inode, iter, fat_get_block);
 283         if (ret < 0 && iov_iter_rw(iter) == WRITE)
 284                 fat_write_failed(mapping, offset + count);
 285
 286         return ret;
 287 }
 288
 289 static int fat_get_block_bmap(struct inode *inode, sector_t iblock,
 290                 struct buffer_head *bh_result, int create)
 291 {
 292         struct super_block *sb = inode->i_sb;
 293         unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
 294         int err;
 295         sector_t bmap;
 296         unsigned long mapped_blocks;
 297
 298         BUG_ON(create != 0);
 299
 300         err = fat_bmap(inode, iblock, &bmap, &mapped_blocks, create, true);
 301         if (err)
 302                 return err;
 303
 304         if (bmap) {
 305                 map_bh(bh_result, sb, bmap);
 306                 max_blocks = min(mapped_blocks, max_blocks);
 307         }
 308
 309         bh_result->b_size = max_blocks << sb->s_blocksize_bits;
 310
 311         return 0;
 312 }
 313
 314 static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
 315 {
 316         sector_t blocknr;
 317
 318         /* fat_get_cluster() assumes the requested blocknr isn't truncated. */
 319         down_read(&MSDOS_I(mapping->host)->truncate_lock);
 320         blocknr = generic_block_bmap(mapping, block, fat_get_block_bmap);
 321         up_read(&MSDOS_I(mapping->host)->truncate_lock);
 322
 323         return blocknr;
 324 }
 325
 326 /*
 327  * fat_block_truncate_page() zeroes out a mapping from file offset `from'
 328  * up to the end of the block which corresponds to `from'.
 329  * This is required during truncate to physically zeroout the tail end
 330  * of that block so it doesn't yield old data if the file is later grown.
 331  * Also, avoid causing failure from fsx for cases of "data past EOF"
 332  */
 333 int fat_block_truncate_page(struct inode *inode, loff_t from)
 334 {
 335         return block_truncate_page(inode->i_mapping, from, fat_get_block);
 336 }
 337
 338 static const struct address_space_operations fat_aops = {
 339         .readpage       = fat_readpage,
 340         .readpages      = fat_readpages,
 341         .writepage      = fat_writepage,
 342         .writepages     = fat_writepages,
 343         .write_begin    = fat_write_begin,
 344         .write_end      = fat_write_end,
 345         .direct_IO      = fat_direct_IO,
 346         .bmap           = _fat_bmap
 347 };
 348
 349 /*
 350  * New FAT inode stuff. We do the following:
 351  *      a) i_ino is constant and has nothing with on-disk location.
 352  *      b) FAT manages its own cache of directory entries.
 353  *      c) *This* cache is indexed by on-disk location.
 354  *      d) inode has an associated directory entry, all right, but
 355  *              it may be unhashed.
 356  *      e) currently entries are stored within struct inode. That should
 357  *              change.
 358  *      f) we deal with races in the following way:
 359  *              1. readdir() and lookup() do FAT-dir-cache lookup.
 360  *              2. rename() unhashes the F-d-c entry and rehashes it in
 361  *                      a new place.
 362  *              3. unlink() and rmdir() unhash F-d-c entry.
 363  *              4. fat_write_inode() checks whether the thing is unhashed.
 364  *                      If it is we silently return. If it isn't we do bread(),
 365  *                      check if the location is still valid and retry if it
 366  *                      isn't. Otherwise we do changes.
 367  *              5. Spinlock is used to protect hash/unhash/location check/lookup
 368  *              6. fat_evict_inode() unhashes the F-d-c entry.
 369  *              7. lookup() and readdir() do igrab() if they find a F-d-c entry
 370  *                      and consider negative result as cache miss.
 371  */
 372
 373 static void fat_hash_init(struct super_block *sb)
 374 {
 375         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 376         int i;
 377
 378         spin_lock_init(&sbi->inode_hash_lock);
 379         for (i = 0; i < FAT_HASH_SIZE; i++)
 380                 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
 381 }
 382
 383 static inline unsigned long fat_hash(loff_t i_pos)
 384 {
 385         return hash_32(i_pos, FAT_HASH_BITS);
 386 }
 387
 388 static void dir_hash_init(struct super_block *sb)
 389 {
 390         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 391         int i;
 392
 393         spin_lock_init(&sbi->dir_hash_lock);
 394         for (i = 0; i < FAT_HASH_SIZE; i++)
 395                 INIT_HLIST_HEAD(&sbi->dir_hashtable[i]);
 396 }
 397
 398 void fat_attach(struct inode *inode, loff_t i_pos)
 399 {
 400         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
 401
 402         if (inode->i_ino != MSDOS_ROOT_INO) {
 403                 struct hlist_head *head =   sbi->inode_hashtable
 404                                           + fat_hash(i_pos);
 405
 406                 spin_lock(&sbi->inode_hash_lock);
 407                 MSDOS_I(inode)->i_pos = i_pos;
 408                 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
 409                 spin_unlock(&sbi->inode_hash_lock);
 410         }
 411
 412         /* If NFS support is enabled, cache the mapping of start cluster
 413          * to directory inode. This is used during reconnection of
 414          * dentries to the filesystem root.
 415          */
 416         if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
 417                 struct hlist_head *d_head = sbi->dir_hashtable;
 418                 d_head += fat_dir_hash(MSDOS_I(inode)->i_logstart);
 419
 420                 spin_lock(&sbi->dir_hash_lock);
 421                 hlist_add_head(&MSDOS_I(inode)->i_dir_hash, d_head);
 422                 spin_unlock(&sbi->dir_hash_lock);
 423         }
 424 }
 425 EXPORT_SYMBOL_GPL(fat_attach);
 426
 427 void fat_detach(struct inode *inode)
 428 {
 429         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
 430         spin_lock(&sbi->inode_hash_lock);
 431         MSDOS_I(inode)->i_pos = 0;
 432         hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
 433         spin_unlock(&sbi->inode_hash_lock);
 434
 435         if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
 436                 spin_lock(&sbi->dir_hash_lock);
 437                 hlist_del_init(&MSDOS_I(inode)->i_dir_hash);
 438                 spin_unlock(&sbi->dir_hash_lock);
 439         }
 440 }
 441 EXPORT_SYMBOL_GPL(fat_detach);
 442
 443 struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
 444 {
 445         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 446         struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
 447         struct msdos_inode_info *i;
 448         struct inode *inode = NULL;
 449
 450         spin_lock(&sbi->inode_hash_lock);
 451         hlist_for_each_entry(i, head, i_fat_hash) {
 452                 BUG_ON(i->vfs_inode.i_sb != sb);
 453                 if (i->i_pos != i_pos)
 454                         continue;
 455                 inode = igrab(&i->vfs_inode);
 456                 if (inode)
 457                         break;
 458         }
 459         spin_unlock(&sbi->inode_hash_lock);
 460         return inode;
 461 }
 462
 463 static int is_exec(unsigned char *extension)
 464 {
 465         unsigned char exe_extensions[] = "EXECOMBAT", *walk;
 466
 467         for (walk = exe_extensions; *walk; walk += 3)
 468                 if (!strncmp(extension, walk, 3))
 469                         return 1;
 470         return 0;
 471 }
 472
 473 static int fat_calc_dir_size(struct inode *inode)
 474 {
 475         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
 476         int ret, fclus, dclus;
 477
 478         inode->i_size = 0;
 479         if (MSDOS_I(inode)->i_start == 0)
 480                 return 0;
 481
 482         ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
 483         if (ret < 0)
 484                 return ret;
 485         inode->i_size = (fclus + 1) << sbi->cluster_bits;
 486
 487         return 0;
 488 }
 489
 490 static int fat_validate_dir(struct inode *dir)
 491 {
 492         struct super_block *sb = dir->i_sb;
 493
 494         if (dir->i_nlink < 2) {
 495                 /* Directory should have "."/".." entries at least. */
 496                 fat_fs_error(sb, "corrupted directory (invalid entries)");
 497                 return -EIO;
 498         }
 499         if (MSDOS_I(dir)->i_start == 0 ||
 500             MSDOS_I(dir)->i_start == MSDOS_SB(sb)->root_cluster) {
 501                 /* Directory should point valid cluster. */
 502                 fat_fs_error(sb, "corrupted directory (invalid i_start)");
 503                 return -EIO;
 504         }
 505         return 0;
 506 }
 507
 508 /* doesn't deal with root inode */
 509 int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
 510 {
 511         struct timespec ts;
 512         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
 513         int error;
 514
 515         MSDOS_I(inode)->i_pos = 0;
 516         inode->i_uid = sbi->options.fs_uid;
 517         inode->i_gid = sbi->options.fs_gid;
 518         inode_inc_iversion(inode);
 519         inode->i_generation = get_seconds();
 520
 521         if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
 522                 inode->i_generation &= ~1;
 523                 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
 524                 inode->i_op = sbi->dir_ops;
 525                 inode->i_fop = &fat_dir_operations;
 526
 527                 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
 528                 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
 529                 error = fat_calc_dir_size(inode);
 530                 if (error < 0)
 531                         return error;
 532                 MSDOS_I(inode)->mmu_private = inode->i_size;
 533
 534                 set_nlink(inode, fat_subdirs(inode));
 535
 536                 error = fat_validate_dir(inode);
 537                 if (error < 0)
 538                         return error;
 539         } else { /* not a directory */
 540                 inode->i_generation |= 1;
 541                 inode->i_mode = fat_make_mode(sbi, de->attr,
 542                         ((sbi->options.showexec && !is_exec(de->name + 8))
 543                          ? S_IRUGO|S_IWUGO : S_IRWXUGO));
 544                 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
 545
 546                 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
 547                 inode->i_size = le32_to_cpu(de->size);
 548                 inode->i_op = &fat_file_inode_operations;
 549                 inode->i_fop = &fat_file_operations;
 550                 inode->i_mapping->a_ops = &fat_aops;
 551                 MSDOS_I(inode)->mmu_private = inode->i_size;
 552         }
 553         if (de->attr & ATTR_SYS) {
 554                 if (sbi->options.sys_immutable)
 555                         inode->i_flags |= S_IMMUTABLE;
 556         }
 557         fat_save_attrs(inode, de->attr);
 558
 559         inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
 560                            & ~((loff_t)sbi->cluster_size - 1)) >> 9;
 561
 562         fat_time_fat2unix(sbi, &ts, de->time, de->date, 0);
 563         inode->i_mtime = timespec_to_timespec64(ts);
 564         if (sbi->options.isvfat) {
 565                 fat_time_fat2unix(sbi, &ts, de->ctime,
 566                                   de->cdate, de->ctime_cs);
 567                 inode->i_ctime = timespec_to_timespec64(ts);
 568                 fat_time_fat2unix(sbi, &ts, 0, de->adate, 0);
 569                 inode->i_atime = timespec_to_timespec64(ts);
 570         } else
 571                 inode->i_ctime = inode->i_atime = inode->i_mtime;
 572
 573         return 0;
 574 }
 575
 576 static inline void fat_lock_build_inode(struct msdos_sb_info *sbi)
 577 {
 578         if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
 579                 mutex_lock(&sbi->nfs_build_inode_lock);
 580 }
 581
 582 static inline void fat_unlock_build_inode(struct msdos_sb_info *sbi)
 583 {
 584         if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
 585                 mutex_unlock(&sbi->nfs_build_inode_lock);
 586 }
 587
 588 struct inode *fat_build_inode(struct super_block *sb,
 589                         struct msdos_dir_entry *de, loff_t i_pos)
 590 {
 591         struct inode *inode;
 592         int err;
 593
 594         fat_lock_build_inode(MSDOS_SB(sb));
 595         inode = fat_iget(sb, i_pos);
 596         if (inode)
 597                 goto out;
 598         inode = new_inode(sb);
 599         if (!inode) {
 600                 inode = ERR_PTR(-ENOMEM);
 601                 goto out;
 602         }
 603         inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
 604         inode_set_iversion(inode, 1);
 605         err = fat_fill_inode(inode, de);
 606         if (err) {
 607                 iput(inode);
 608                 inode = ERR_PTR(err);
 609                 goto out;
 610         }
 611         fat_attach(inode, i_pos);
 612         insert_inode_hash(inode);
 613 out:
 614         fat_unlock_build_inode(MSDOS_SB(sb));
 615         return inode;
 616 }
 617
 618 EXPORT_SYMBOL_GPL(fat_build_inode);
 619
 620 static int __fat_write_inode(struct inode *inode, int wait);
 621
 622 static void fat_free_eofblocks(struct inode *inode)
 623 {
 624         /* Release unwritten fallocated blocks on inode eviction. */
 625         if ((inode->i_blocks << 9) >
 626                         round_up(MSDOS_I(inode)->mmu_private,
 627                                 MSDOS_SB(inode->i_sb)->cluster_size)) {
 628                 int err;
 629
 630                 fat_truncate_blocks(inode, MSDOS_I(inode)->mmu_private);
 631                 /* Fallocate results in updating the i_start/iogstart
 632                  * for the zero byte file. So, make it return to
 633                  * original state during evict and commit it to avoid
 634                  * any corruption on the next access to the cluster
 635                  * chain for the file.
 636                  */
 637                 err = __fat_write_inode(inode, inode_needs_sync(inode));
 638                 if (err) {
 639                         fat_msg(inode->i_sb, KERN_WARNING, "Failed to "
 640                                         "update on disk inode for unused "
 641                                         "fallocated blocks, inode could be "
 642                                         "corrupted. Please run fsck");
 643                 }
 644
 645         }
 646 }
 647
 648 static void fat_evict_inode(struct inode *inode)
 649 {
 650         truncate_inode_pages_final(&inode->i_data);
 651         if (!inode->i_nlink) {
 652                 inode->i_size = 0;
 653                 fat_truncate_blocks(inode, 0);
 654         } else
 655                 fat_free_eofblocks(inode);
 656
 657         invalidate_inode_buffers(inode);
 658         clear_inode(inode);
 659         fat_cache_inval_inode(inode);
 660         fat_detach(inode);
 661 }
 662
 663 static void fat_set_state(struct super_block *sb,
 664                         unsigned int set, unsigned int force)
 665 {
 666         struct buffer_head *bh;
 667         struct fat_boot_sector *b;
 668         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 669
 670         /* do not change any thing if mounted read only */
 671         if (sb_rdonly(sb) && !force)
 672                 return;
 673
 674         /* do not change state if fs was dirty */
 675         if (sbi->dirty) {
 676                 /* warn only on set (mount). */
 677                 if (set)
 678                         fat_msg(sb, KERN_WARNING, "Volume was not properly "
 679                                 "unmounted. Some data may be corrupt. "
 680                                 "Please run fsck.");
 681                 return;
 682         }
 683
 684         bh = sb_bread(sb, 0);
 685         if (bh == NULL) {
 686                 fat_msg(sb, KERN_ERR, "unable to read boot sector "
 687                         "to mark fs as dirty");
 688                 return;
 689         }
 690
 691         b = (struct fat_boot_sector *) bh->b_data;
 692
 693         if (sbi->fat_bits == 32) {
 694                 if (set)
 695                         b->fat32.state |= FAT_STATE_DIRTY;
 696                 else
 697                         b->fat32.state &= ~FAT_STATE_DIRTY;
 698         } else /* fat 16 and 12 */ {
 699                 if (set)
 700                         b->fat16.state |= FAT_STATE_DIRTY;
 701                 else
 702                         b->fat16.state &= ~FAT_STATE_DIRTY;
 703         }
 704
 705         mark_buffer_dirty(bh);
 706         sync_dirty_buffer(bh);
 707         brelse(bh);
 708 }
 709
 710 static void fat_reset_iocharset(struct fat_mount_options *opts)
 711 {
 712         if (opts->iocharset != fat_default_iocharset) {
 713                 /* Note: opts->iocharset can be NULL here */
 714                 kfree(opts->iocharset);
 715                 opts->iocharset = fat_default_iocharset;
 716         }
 717 }
 718
 719 static void delayed_free(struct rcu_head *p)
 720 {
 721         struct msdos_sb_info *sbi = container_of(p, struct msdos_sb_info, rcu);
 722         unload_nls(sbi->nls_disk);
 723         unload_nls(sbi->nls_io);
 724         fat_reset_iocharset(&sbi->options);
 725         kfree(sbi);
 726 }
 727
 728 static void fat_put_super(struct super_block *sb)
 729 {
 730         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 731
 732         fat_set_state(sb, 0, 0);
 733
 734         iput(sbi->fsinfo_inode);
 735         iput(sbi->fat_inode);
 736
 737         call_rcu(&sbi->rcu, delayed_free);
 738 }
 739
 740 static struct kmem_cache *fat_inode_cachep;
 741
 742 static struct inode *fat_alloc_inode(struct super_block *sb)
 743 {
 744         struct msdos_inode_info *ei;
 745         ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
 746         if (!ei)
 747                 return NULL;
 748
 749         init_rwsem(&ei->truncate_lock);
 750         return &ei->vfs_inode;
 751 }
 752
 753 static void fat_i_callback(struct rcu_head *head)
 754 {
 755         struct inode *inode = container_of(head, struct inode, i_rcu);
 756         kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
 757 }
 758
 759 static void fat_destroy_inode(struct inode *inode)
 760 {
 761         call_rcu(&inode->i_rcu, fat_i_callback);
 762 }
 763
 764 static void init_once(void *foo)
 765 {
 766         struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
 767
 768         spin_lock_init(&ei->cache_lru_lock);
 769         ei->nr_caches = 0;
 770         ei->cache_valid_id = FAT_CACHE_VALID + 1;
 771         INIT_LIST_HEAD(&ei->cache_lru);
 772         INIT_HLIST_NODE(&ei->i_fat_hash);
 773         INIT_HLIST_NODE(&ei->i_dir_hash);
 774         inode_init_once(&ei->vfs_inode);
 775 }
 776
 777 static int __init fat_init_inodecache(void)
 778 {
 779         fat_inode_cachep = kmem_cache_create("fat_inode_cache",
 780                                              sizeof(struct msdos_inode_info),
 781                                              0, (SLAB_RECLAIM_ACCOUNT|
 782                                                 SLAB_MEM_SPREAD|SLAB_ACCOUNT),
 783                                              init_once);
 784         if (fat_inode_cachep == NULL)
 785                 return -ENOMEM;
 786         return 0;
 787 }
 788
 789 static void __exit fat_destroy_inodecache(void)
 790 {
 791         /*
 792          * Make sure all delayed rcu free inodes are flushed before we
 793          * destroy cache.
 794          */
 795         rcu_barrier();
 796         kmem_cache_destroy(fat_inode_cachep);
 797 }
 798
 799 static int fat_remount(struct super_block *sb, int *flags, char *data)
 800 {
 801         bool new_rdonly;
 802         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 803         *flags |= SB_NODIRATIME | (sbi->options.isvfat ? 0 : SB_NOATIME);
 804
 805         sync_filesystem(sb);
 806
 807         /* make sure we update state on remount. */
 808         new_rdonly = *flags & SB_RDONLY;
 809         if (new_rdonly != sb_rdonly(sb)) {
 810                 if (new_rdonly)
 811                         fat_set_state(sb, 0, 0);
 812                 else
 813                         fat_set_state(sb, 1, 1);
 814         }
 815         return 0;
 816 }
 817
 818 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
 819 {
 820         struct super_block *sb = dentry->d_sb;
 821         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 822         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 823
 824         /* If the count of free cluster is still unknown, counts it here. */
 825         if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
 826                 int err = fat_count_free_clusters(dentry->d_sb);
 827                 if (err)
 828                         return err;
 829         }
 830
 831         buf->f_type = dentry->d_sb->s_magic;
 832         buf->f_bsize = sbi->cluster_size;
 833         buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
 834         buf->f_bfree = sbi->free_clusters;
 835         buf->f_bavail = sbi->free_clusters;
 836         buf->f_fsid.val[0] = (u32)id;
 837         buf->f_fsid.val[1] = (u32)(id >> 32);
 838         buf->f_namelen =
 839                 (sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE;
 840
 841         return 0;
 842 }
 843
 844 static int __fat_write_inode(struct inode *inode, int wait)
 845 {
 846         struct timespec ts;
 847         struct super_block *sb = inode->i_sb;
 848         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 849         struct buffer_head *bh;
 850         struct msdos_dir_entry *raw_entry;
 851         loff_t i_pos;
 852         sector_t blocknr;
 853         int err, offset;
 854
 855         if (inode->i_ino == MSDOS_ROOT_INO)
 856                 return 0;
 857
 858 retry:
 859         i_pos = fat_i_pos_read(sbi, inode);
 860         if (!i_pos)
 861                 return 0;
 862
 863         fat_get_blknr_offset(sbi, i_pos, &blocknr, &offset);
 864         bh = sb_bread(sb, blocknr);
 865         if (!bh) {
 866                 fat_msg(sb, KERN_ERR, "unable to read inode block "
 867                        "for updating (i_pos %lld)", i_pos);
 868                 return -EIO;
 869         }
 870         spin_lock(&sbi->inode_hash_lock);
 871         if (i_pos != MSDOS_I(inode)->i_pos) {
 872                 spin_unlock(&sbi->inode_hash_lock);
 873                 brelse(bh);
 874                 goto retry;
 875         }
 876
 877         raw_entry = &((struct msdos_dir_entry *) (bh->b_data))[offset];
 878         if (S_ISDIR(inode->i_mode))
 879                 raw_entry->size = 0;
 880         else
 881                 raw_entry->size = cpu_to_le32(inode->i_size);
 882         raw_entry->attr = fat_make_attrs(inode);
 883         fat_set_start(raw_entry, MSDOS_I(inode)->i_logstart);
 884         ts = timespec64_to_timespec(inode->i_mtime);
 885         fat_time_unix2fat(sbi, &ts, &raw_entry->time,
 886                           &raw_entry->date, NULL);
 887         if (sbi->options.isvfat) {
 888                 __le16 atime;
 889                 ts = timespec64_to_timespec(inode->i_ctime);
 890                 fat_time_unix2fat(sbi, &ts, &raw_entry->ctime,
 891                                   &raw_entry->cdate, &raw_entry->ctime_cs);
 892                 ts = timespec64_to_timespec(inode->i_atime);
 893                 fat_time_unix2fat(sbi, &ts, &atime,
 894                                   &raw_entry->adate, NULL);
 895         }
 896         spin_unlock(&sbi->inode_hash_lock);
 897         mark_buffer_dirty(bh);
 898         err = 0;
 899         if (wait)
 900                 err = sync_dirty_buffer(bh);
 901         brelse(bh);
 902         return err;
 903 }
 904
 905 static int fat_write_inode(struct inode *inode, struct writeback_control *wbc)
 906 {
 907         int err;
 908
 909         if (inode->i_ino == MSDOS_FSINFO_INO) {
 910                 struct super_block *sb = inode->i_sb;
 911
 912                 mutex_lock(&MSDOS_SB(sb)->s_lock);
 913                 err = fat_clusters_flush(sb);
 914                 mutex_unlock(&MSDOS_SB(sb)->s_lock);
 915         } else
 916                 err = __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
 917
 918         return err;
 919 }
 920
 921 int fat_sync_inode(struct inode *inode)
 922 {
 923         return __fat_write_inode(inode, 1);
 924 }
 925
 926 EXPORT_SYMBOL_GPL(fat_sync_inode);
 927
 928 static int fat_show_options(struct seq_file *m, struct dentry *root);
 929 static const struct super_operations fat_sops = {
 930         .alloc_inode    = fat_alloc_inode,
 931         .destroy_inode  = fat_destroy_inode,
 932         .write_inode    = fat_write_inode,
 933         .evict_inode    = fat_evict_inode,
 934         .put_super      = fat_put_super,
 935         .statfs         = fat_statfs,
 936         .remount_fs     = fat_remount,
 937
 938         .show_options   = fat_show_options,
 939 };
 940
 941 static int fat_show_options(struct seq_file *m, struct dentry *root)
 942 {
 943         struct msdos_sb_info *sbi = MSDOS_SB(root->d_sb);
 944         struct fat_mount_options *opts = &sbi->options;
 945         int isvfat = opts->isvfat;
 946
 947         if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
 948                 seq_printf(m, ",uid=%u",
 949                                 from_kuid_munged(&init_user_ns, opts->fs_uid));
 950         if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
 951                 seq_printf(m, ",gid=%u",
 952                                 from_kgid_munged(&init_user_ns, opts->fs_gid));
 953         seq_printf(m, ",fmask=%04o", opts->fs_fmask);
 954         seq_printf(m, ",dmask=%04o", opts->fs_dmask);
 955         if (opts->allow_utime)
 956                 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
 957         if (sbi->nls_disk)
 958                 /* strip "cp" prefix from displayed option */
 959                 seq_printf(m, ",codepage=%s", &sbi->nls_disk->charset[2]);
 960         if (isvfat) {
 961                 if (sbi->nls_io)
 962                         seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
 963
 964                 switch (opts->shortname) {
 965                 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
 966                         seq_puts(m, ",shortname=win95");
 967                         break;
 968                 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
 969                         seq_puts(m, ",shortname=winnt");
 970                         break;
 971                 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
 972                         seq_puts(m, ",shortname=mixed");
 973                         break;
 974                 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
 975                         seq_puts(m, ",shortname=lower");
 976                         break;
 977                 default:
 978                         seq_puts(m, ",shortname=unknown");
 979                         break;
 980                 }
 981         }
 982         if (opts->name_check != 'n')
 983                 seq_printf(m, ",check=%c", opts->name_check);
 984         if (opts->usefree)
 985                 seq_puts(m, ",usefree");
 986         if (opts->quiet)
 987                 seq_puts(m, ",quiet");
 988         if (opts->showexec)
 989                 seq_puts(m, ",showexec");
 990         if (opts->sys_immutable)
 991                 seq_puts(m, ",sys_immutable");
 992         if (!isvfat) {
 993                 if (opts->dotsOK)
 994                         seq_puts(m, ",dotsOK=yes");
 995                 if (opts->nocase)
 996                         seq_puts(m, ",nocase");
 997         } else {
 998                 if (opts->utf8)
 999                         seq_puts(m, ",utf8");
1000                 if (opts->unicode_xlate)
1001                         seq_puts(m, ",uni_xlate");
1002                 if (!opts->numtail)
1003                         seq_puts(m, ",nonumtail");
1004                 if (opts->rodir)
1005                         seq_puts(m, ",rodir");
1006         }
1007         if (opts->flush)
1008                 seq_puts(m, ",flush");
1009         if (opts->tz_set) {
1010                 if (opts->time_offset)
1011                         seq_printf(m, ",time_offset=%d", opts->time_offset);
1012                 else
1013                         seq_puts(m, ",tz=UTC");
1014         }
1015         if (opts->errors == FAT_ERRORS_CONT)
1016                 seq_puts(m, ",errors=continue");
1017         else if (opts->errors == FAT_ERRORS_PANIC)
1018                 seq_puts(m, ",errors=panic");
1019         else
1020                 seq_puts(m, ",errors=remount-ro");
1021         if (opts->nfs == FAT_NFS_NOSTALE_RO)
1022                 seq_puts(m, ",nfs=nostale_ro");
1023         else if (opts->nfs)
1024                 seq_puts(m, ",nfs=stale_rw");
1025         if (opts->discard)
1026                 seq_puts(m, ",discard");
1027         if (opts->dos1xfloppy)
1028                 seq_puts(m, ",dos1xfloppy");
1029
1030         return 0;
1031 }
1032
1033 enum {
1034         Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
1035         Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
1036         Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
1037         Opt_immutable, Opt_dots, Opt_nodots,
1038         Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
1039         Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
1040         Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
1041         Opt_obsolete, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
1042         Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_time_offset,
1043         Opt_nfs_stale_rw, Opt_nfs_nostale_ro, Opt_err, Opt_dos1xfloppy,
1044 };
1045
1046 static const match_table_t fat_tokens = {
1047         {Opt_check_r, "check=relaxed"},
1048         {Opt_check_s, "check=strict"},
1049         {Opt_check_n, "check=normal"},
1050         {Opt_check_r, "check=r"},
1051         {Opt_check_s, "check=s"},
1052         {Opt_check_n, "check=n"},
1053         {Opt_uid, "uid=%u"},
1054         {Opt_gid, "gid=%u"},
1055         {Opt_umask, "umask=%o"},
1056         {Opt_dmask, "dmask=%o"},
1057         {Opt_fmask, "fmask=%o"},
1058         {Opt_allow_utime, "allow_utime=%o"},
1059         {Opt_codepage, "codepage=%u"},
1060         {Opt_usefree, "usefree"},
1061         {Opt_nocase, "nocase"},
1062         {Opt_quiet, "quiet"},
1063         {Opt_showexec, "showexec"},
1064         {Opt_debug, "debug"},
1065         {Opt_immutable, "sys_immutable"},
1066         {Opt_flush, "flush"},
1067         {Opt_tz_utc, "tz=UTC"},
1068         {Opt_time_offset, "time_offset=%d"},
1069         {Opt_err_cont, "errors=continue"},
1070         {Opt_err_panic, "errors=panic"},
1071         {Opt_err_ro, "errors=remount-ro"},
1072         {Opt_discard, "discard"},
1073         {Opt_nfs_stale_rw, "nfs"},
1074         {Opt_nfs_stale_rw, "nfs=stale_rw"},
1075         {Opt_nfs_nostale_ro, "nfs=nostale_ro"},
1076         {Opt_dos1xfloppy, "dos1xfloppy"},
1077         {Opt_obsolete, "conv=binary"},
1078         {Opt_obsolete, "conv=text"},
1079         {Opt_obsolete, "conv=auto"},
1080         {Opt_obsolete, "conv=b"},
1081         {Opt_obsolete, "conv=t"},
1082         {Opt_obsolete, "conv=a"},
1083         {Opt_obsolete, "fat=%u"},
1084         {Opt_obsolete, "blocksize=%u"},
1085         {Opt_obsolete, "cvf_format=%20s"},
1086         {Opt_obsolete, "cvf_options=%100s"},
1087         {Opt_obsolete, "posix"},
1088         {Opt_err, NULL},
1089 };
1090 static const match_table_t msdos_tokens = {
1091         {Opt_nodots, "nodots"},
1092         {Opt_nodots, "dotsOK=no"},
1093         {Opt_dots, "dots"},
1094         {Opt_dots, "dotsOK=yes"},
1095         {Opt_err, NULL}
1096 };
1097 static const match_table_t vfat_tokens = {
1098         {Opt_charset, "iocharset=%s"},
1099         {Opt_shortname_lower, "shortname=lower"},
1100         {Opt_shortname_win95, "shortname=win95"},
1101         {Opt_shortname_winnt, "shortname=winnt"},
1102         {Opt_shortname_mixed, "shortname=mixed"},
1103         {Opt_utf8_no, "utf8=0"},                /* 0 or no or false */
1104         {Opt_utf8_no, "utf8=no"},
1105         {Opt_utf8_no, "utf8=false"},
1106         {Opt_utf8_yes, "utf8=1"},               /* empty or 1 or yes or true */
1107         {Opt_utf8_yes, "utf8=yes"},
1108         {Opt_utf8_yes, "utf8=true"},
1109         {Opt_utf8_yes, "utf8"},
1110         {Opt_uni_xl_no, "uni_xlate=0"},         /* 0 or no or false */
1111         {Opt_uni_xl_no, "uni_xlate=no"},
1112         {Opt_uni_xl_no, "uni_xlate=false"},
1113         {Opt_uni_xl_yes, "uni_xlate=1"},        /* empty or 1 or yes or true */
1114         {Opt_uni_xl_yes, "uni_xlate=yes"},
1115         {Opt_uni_xl_yes, "uni_xlate=true"},
1116         {Opt_uni_xl_yes, "uni_xlate"},
1117         {Opt_nonumtail_no, "nonumtail=0"},      /* 0 or no or false */
1118         {Opt_nonumtail_no, "nonumtail=no"},
1119         {Opt_nonumtail_no, "nonumtail=false"},
1120         {Opt_nonumtail_yes, "nonumtail=1"},     /* empty or 1 or yes or true */
1121         {Opt_nonumtail_yes, "nonumtail=yes"},
1122         {Opt_nonumtail_yes, "nonumtail=true"},
1123         {Opt_nonumtail_yes, "nonumtail"},
1124         {Opt_rodir, "rodir"},
1125         {Opt_err, NULL}
1126 };
1127
1128 static int parse_options(struct super_block *sb, char *options, int is_vfat,
1129                          int silent, int *debug, struct fat_mount_options *opts)
1130 {
1131         char *p;
1132         substring_t args[MAX_OPT_ARGS];
1133         int option;
1134         char *iocharset;
1135
1136         opts->isvfat = is_vfat;
1137
1138         opts->fs_uid = current_uid();
1139         opts->fs_gid = current_gid();
1140         opts->fs_fmask = opts->fs_dmask = current_umask();
1141         opts->allow_utime = -1;
1142         opts->codepage = fat_default_codepage;
1143         fat_reset_iocharset(opts);
1144         if (is_vfat) {
1145                 opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95;
1146                 opts->rodir = 0;
1147         } else {
1148                 opts->shortname = 0;
1149                 opts->rodir = 1;
1150         }
1151         opts->name_check = 'n';
1152         opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK =  0;
1153         opts->unicode_xlate = 0;
1154         opts->numtail = 1;
1155         opts->usefree = opts->nocase = 0;
1156         opts->tz_set = 0;
1157         opts->nfs = 0;
1158         opts->errors = FAT_ERRORS_RO;
1159         *debug = 0;
1160
1161         opts->utf8 = IS_ENABLED(CONFIG_FAT_DEFAULT_UTF8) && is_vfat;
1162
1163         if (!options)
1164                 goto out;
1165
1166         while ((p = strsep(&options, ",")) != NULL) {
1167                 int token;
1168                 if (!*p)
1169                         continue;
1170
1171                 token = match_token(p, fat_tokens, args);
1172                 if (token == Opt_err) {
1173                         if (is_vfat)
1174                                 token = match_token(p, vfat_tokens, args);
1175                         else
1176                                 token = match_token(p, msdos_tokens, args);
1177                 }
1178                 switch (token) {
1179                 case Opt_check_s:
1180                         opts->name_check = 's';
1181                         break;
1182                 case Opt_check_r:
1183                         opts->name_check = 'r';
1184                         break;
1185                 case Opt_check_n:
1186                         opts->name_check = 'n';
1187                         break;
1188                 case Opt_usefree:
1189                         opts->usefree = 1;
1190                         break;
1191                 case Opt_nocase:
1192                         if (!is_vfat)
1193                                 opts->nocase = 1;
1194                         else {
1195                                 /* for backward compatibility */
1196                                 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1197                                         | VFAT_SFN_CREATE_WIN95;
1198                         }
1199                         break;
1200                 case Opt_quiet:
1201                         opts->quiet = 1;
1202                         break;
1203                 case Opt_showexec:
1204                         opts->showexec = 1;
1205                         break;
1206                 case Opt_debug:
1207                         *debug = 1;
1208                         break;
1209                 case Opt_immutable:
1210                         opts->sys_immutable = 1;
1211                         break;
1212                 case Opt_uid:
1213                         if (match_int(&args[0], &option))
1214                                 return -EINVAL;
1215                         opts->fs_uid = make_kuid(current_user_ns(), option);
1216                         if (!uid_valid(opts->fs_uid))
1217                                 return -EINVAL;
1218                         break;
1219                 case Opt_gid:
1220                         if (match_int(&args[0], &option))
1221                                 return -EINVAL;
1222                         opts->fs_gid = make_kgid(current_user_ns(), option);
1223                         if (!gid_valid(opts->fs_gid))
1224                                 return -EINVAL;
1225                         break;
1226                 case Opt_umask:
1227                         if (match_octal(&args[0], &option))
1228                                 return -EINVAL;
1229                         opts->fs_fmask = opts->fs_dmask = option;
1230                         break;
1231                 case Opt_dmask:
1232                         if (match_octal(&args[0], &option))
1233                                 return -EINVAL;
1234                         opts->fs_dmask = option;
1235                         break;
1236                 case Opt_fmask:
1237                         if (match_octal(&args[0], &option))
1238                                 return -EINVAL;
1239                         opts->fs_fmask = option;
1240                         break;
1241                 case Opt_allow_utime:
1242                         if (match_octal(&args[0], &option))
1243                                 return -EINVAL;
1244                         opts->allow_utime = option & (S_IWGRP | S_IWOTH);
1245                         break;
1246                 case Opt_codepage:
1247                         if (match_int(&args[0], &option))
1248                                 return -EINVAL;
1249                         opts->codepage = option;
1250                         break;
1251                 case Opt_flush:
1252                         opts->flush = 1;
1253                         break;
1254                 case Opt_time_offset:
1255                         if (match_int(&args[0], &option))
1256                                 return -EINVAL;
1257                         /*
1258                          * GMT+-12 zones may have DST corrections so at least
1259                          * 13 hours difference is needed. Make the limit 24
1260                          * just in case someone invents something unusual.
1261                          */
1262                         if (option < -24 * 60 || option > 24 * 60)
1263                                 return -EINVAL;
1264                         opts->tz_set = 1;
1265                         opts->time_offset = option;
1266                         break;
1267                 case Opt_tz_utc:
1268                         opts->tz_set = 1;
1269                         opts->time_offset = 0;
1270                         break;
1271                 case Opt_err_cont:
1272                         opts->errors = FAT_ERRORS_CONT;
1273                         break;
1274                 case Opt_err_panic:
1275                         opts->errors = FAT_ERRORS_PANIC;
1276                         break;
1277                 case Opt_err_ro:
1278                         opts->errors = FAT_ERRORS_RO;
1279                         break;
1280                 case Opt_nfs_stale_rw:
1281                         opts->nfs = FAT_NFS_STALE_RW;
1282                         break;
1283                 case Opt_nfs_nostale_ro:
1284                         opts->nfs = FAT_NFS_NOSTALE_RO;
1285                         break;
1286                 case Opt_dos1xfloppy:
1287                         opts->dos1xfloppy = 1;
1288                         break;
1289
1290                 /* msdos specific */
1291                 case Opt_dots:
1292                         opts->dotsOK = 1;
1293                         break;
1294                 case Opt_nodots:
1295                         opts->dotsOK = 0;
1296                         break;
1297
1298                 /* vfat specific */
1299                 case Opt_charset:
1300                         fat_reset_iocharset(opts);
1301                         iocharset = match_strdup(&args[0]);
1302                         if (!iocharset)
1303                                 return -ENOMEM;
1304                         opts->iocharset = iocharset;
1305                         break;
1306                 case Opt_shortname_lower:
1307                         opts->shortname = VFAT_SFN_DISPLAY_LOWER
1308                                         | VFAT_SFN_CREATE_WIN95;
1309                         break;
1310                 case Opt_shortname_win95:
1311                         opts->shortname = VFAT_SFN_DISPLAY_WIN95
1312                                         | VFAT_SFN_CREATE_WIN95;
1313                         break;
1314                 case Opt_shortname_winnt:
1315                         opts->shortname = VFAT_SFN_DISPLAY_WINNT
1316                                         | VFAT_SFN_CREATE_WINNT;
1317                         break;
1318                 case Opt_shortname_mixed:
1319                         opts->shortname = VFAT_SFN_DISPLAY_WINNT
1320                                         | VFAT_SFN_CREATE_WIN95;
1321                         break;
1322                 case Opt_utf8_no:               /* 0 or no or false */
1323                         opts->utf8 = 0;
1324                         break;
1325                 case Opt_utf8_yes:              /* empty or 1 or yes or true */
1326                         opts->utf8 = 1;
1327                         break;
1328                 case Opt_uni_xl_no:             /* 0 or no or false */
1329                         opts->unicode_xlate = 0;
1330                         break;
1331                 case Opt_uni_xl_yes:            /* empty or 1 or yes or true */
1332                         opts->unicode_xlate = 1;
1333                         break;
1334                 case Opt_nonumtail_no:          /* 0 or no or false */
1335                         opts->numtail = 1;      /* negated option */
1336                         break;
1337                 case Opt_nonumtail_yes:         /* empty or 1 or yes or true */
1338                         opts->numtail = 0;      /* negated option */
1339                         break;
1340                 case Opt_rodir:
1341                         opts->rodir = 1;
1342                         break;
1343                 case Opt_discard:
1344                         opts->discard = 1;
1345                         break;
1346
1347                 /* obsolete mount options */
1348                 case Opt_obsolete:
1349                         fat_msg(sb, KERN_INFO, "\"%s\" option is obsolete, "
1350                                "not supported now", p);
1351                         break;
1352                 /* unknown option */
1353                 default:
1354                         if (!silent) {
1355                                 fat_msg(sb, KERN_ERR,
1356                                        "Unrecognized mount option \"%s\" "
1357                                        "or missing value", p);
1358                         }
1359                         return -EINVAL;
1360                 }
1361         }
1362
1363 out:
1364         /* UTF-8 doesn't provide FAT semantics */
1365         if (!strcmp(opts->iocharset, "utf8")) {
1366                 fat_msg(sb, KERN_WARNING, "utf8 is not a recommended IO charset"
1367                        " for FAT filesystems, filesystem will be "
1368                        "case sensitive!");
1369         }
1370
1371         /* If user doesn't specify allow_utime, it's initialized from dmask. */
1372         if (opts->allow_utime == (unsigned short)-1)
1373                 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1374         if (opts->unicode_xlate)
1375                 opts->utf8 = 0;
1376         if (opts->nfs == FAT_NFS_NOSTALE_RO) {
1377                 sb->s_flags |= SB_RDONLY;
1378                 sb->s_export_op = &fat_export_ops_nostale;
1379         }
1380
1381         return 0;
1382 }
1383
1384 static void fat_dummy_inode_init(struct inode *inode)
1385 {
1386         /* Initialize this dummy inode to work as no-op. */
1387         MSDOS_I(inode)->mmu_private = 0;
1388         MSDOS_I(inode)->i_start = 0;
1389         MSDOS_I(inode)->i_logstart = 0;
1390         MSDOS_I(inode)->i_attrs = 0;
1391         MSDOS_I(inode)->i_pos = 0;
1392 }
1393
1394 static int fat_read_root(struct inode *inode)
1395 {
1396         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
1397         int error;
1398
1399         MSDOS_I(inode)->i_pos = MSDOS_ROOT_INO;
1400         inode->i_uid = sbi->options.fs_uid;
1401         inode->i_gid = sbi->options.fs_gid;
1402         inode_inc_iversion(inode);
1403         inode->i_generation = 0;
1404         inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
1405         inode->i_op = sbi->dir_ops;
1406         inode->i_fop = &fat_dir_operations;
1407         if (sbi->fat_bits == 32) {
1408                 MSDOS_I(inode)->i_start = sbi->root_cluster;
1409                 error = fat_calc_dir_size(inode);
1410                 if (error < 0)
1411                         return error;
1412         } else {
1413                 MSDOS_I(inode)->i_start = 0;
1414                 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1415         }
1416         inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1417                            & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1418         MSDOS_I(inode)->i_logstart = 0;
1419         MSDOS_I(inode)->mmu_private = inode->i_size;
1420
1421         fat_save_attrs(inode, ATTR_DIR);
1422         inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1423         inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1424         set_nlink(inode, fat_subdirs(inode)+2);
1425
1426         return 0;
1427 }
1428
1429 static unsigned long calc_fat_clusters(struct super_block *sb)
1430 {
1431         struct msdos_sb_info *sbi = MSDOS_SB(sb);
1432
1433         /* Divide first to avoid overflow */
1434         if (sbi->fat_bits != 12) {
1435                 unsigned long ent_per_sec = sb->s_blocksize * 8 / sbi->fat_bits;
1436                 return ent_per_sec * sbi->fat_length;
1437         }
1438
1439         return sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1440 }
1441
1442 static bool fat_bpb_is_zero(struct fat_boot_sector *b)
1443 {
1444         if (get_unaligned_le16(&b->sector_size))
1445                 return false;
1446         if (b->sec_per_clus)
1447                 return false;
1448         if (b->reserved)
1449                 return false;
1450         if (b->fats)
1451                 return false;
1452         if (get_unaligned_le16(&b->dir_entries))
1453                 return false;
1454         if (get_unaligned_le16(&b->sectors))
1455                 return false;
1456         if (b->media)
1457                 return false;
1458         if (b->fat_length)
1459                 return false;
1460         if (b->secs_track)
1461                 return false;
1462         if (b->heads)
1463                 return false;
1464         return true;
1465 }
1466
1467 static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b,
1468         int silent, struct fat_bios_param_block *bpb)
1469 {
1470         int error = -EINVAL;
1471
1472         /* Read in BPB ... */
1473         memset(bpb, 0, sizeof(*bpb));
1474         bpb->fat_sector_size = get_unaligned_le16(&b->sector_size);
1475         bpb->fat_sec_per_clus = b->sec_per_clus;
1476         bpb->fat_reserved = le16_to_cpu(b->reserved);
1477         bpb->fat_fats = b->fats;
1478         bpb->fat_dir_entries = get_unaligned_le16(&b->dir_entries);
1479         bpb->fat_sectors = get_unaligned_le16(&b->sectors);
1480         bpb->fat_fat_length = le16_to_cpu(b->fat_length);
1481         bpb->fat_total_sect = le32_to_cpu(b->total_sect);
1482
1483         bpb->fat16_state = b->fat16.state;
1484         bpb->fat16_vol_id = get_unaligned_le32(b->fat16.vol_id);
1485
1486         bpb->fat32_length = le32_to_cpu(b->fat32.length);
1487         bpb->fat32_root_cluster = le32_to_cpu(b->fat32.root_cluster);
1488         bpb->fat32_info_sector = le16_to_cpu(b->fat32.info_sector);
1489         bpb->fat32_state = b->fat32.state;
1490         bpb->fat32_vol_id = get_unaligned_le32(b->fat32.vol_id);
1491
1492         /* Validate this looks like a FAT filesystem BPB */
1493         if (!bpb->fat_reserved) {
1494                 if (!silent)
1495                         fat_msg(sb, KERN_ERR,
1496                                 "bogus number of reserved sectors");
1497                 goto out;
1498         }
1499         if (!bpb->fat_fats) {
1500                 if (!silent)
1501                         fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
1502                 goto out;
1503         }
1504
1505         /*
1506          * Earlier we checked here that b->secs_track and b->head are nonzero,
1507          * but it turns out valid FAT filesystems can have zero there.
1508          */
1509
1510         if (!fat_valid_media(b->media)) {
1511                 if (!silent)
1512                         fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
1513                                 (unsigned)b->media);
1514                 goto out;
1515         }
1516
1517         if (!is_power_of_2(bpb->fat_sector_size)
1518             || (bpb->fat_sector_size < 512)
1519             || (bpb->fat_sector_size > 4096)) {
1520                 if (!silent)
1521                         fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
1522                                (unsigned)bpb->fat_sector_size);
1523                 goto out;
1524         }
1525
1526         if (!is_power_of_2(bpb->fat_sec_per_clus)) {
1527                 if (!silent)
1528                         fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
1529                                 (unsigned)bpb->fat_sec_per_clus);
1530                 goto out;
1531         }
1532
1533         error = 0;
1534
1535 out:
1536         return error;
1537 }
1538
1539 static int fat_read_static_bpb(struct super_block *sb,
1540         struct fat_boot_sector *b, int silent,
1541         struct fat_bios_param_block *bpb)
1542 {
1543         static const char *notdos1x = "This doesn't look like a DOS 1.x volume";
1544
1545         struct fat_floppy_defaults *fdefaults = NULL;
1546         int error = -EINVAL;
1547         sector_t bd_sects;
1548         unsigned i;
1549
1550         bd_sects = i_size_read(sb->s_bdev->bd_inode) / SECTOR_SIZE;
1551
1552         /* 16-bit DOS 1.x reliably wrote bootstrap short-jmp code */
1553         if (b->ignored[0] != 0xeb || b->ignored[2] != 0x90) {
1554                 if (!silent)
1555                         fat_msg(sb, KERN_ERR,
1556                                 "%s; no bootstrapping code", notdos1x);
1557                 goto out;
1558         }
1559
1560         /*
1561          * If any value in this region is non-zero, it isn't archaic
1562          * DOS.
1563          */
1564         if (!fat_bpb_is_zero(b)) {
1565                 if (!silent)
1566                         fat_msg(sb, KERN_ERR,
1567                                 "%s; DOS 2.x BPB is non-zero", notdos1x);
1568                 goto out;
1569         }
1570
1571         for (i = 0; i < ARRAY_SIZE(floppy_defaults); i++) {
1572                 if (floppy_defaults[i].nr_sectors == bd_sects) {
1573                         fdefaults = &floppy_defaults[i];
1574                         break;
1575                 }
1576         }
1577
1578         if (fdefaults == NULL) {
1579                 if (!silent)
1580                         fat_msg(sb, KERN_WARNING,
1581                                 "This looks like a DOS 1.x volume, but isn't a recognized floppy size (%llu sectors)",
1582                                 (u64)bd_sects);
1583                 goto out;
1584         }
1585
1586         if (!silent)
1587                 fat_msg(sb, KERN_INFO,
1588                         "This looks like a DOS 1.x volume; assuming default BPB values");
1589
1590         memset(bpb, 0, sizeof(*bpb));
1591         bpb->fat_sector_size = SECTOR_SIZE;
1592         bpb->fat_sec_per_clus = fdefaults->sec_per_clus;
1593         bpb->fat_reserved = 1;
1594         bpb->fat_fats = 2;
1595         bpb->fat_dir_entries = fdefaults->dir_entries;
1596         bpb->fat_sectors = fdefaults->nr_sectors;
1597         bpb->fat_fat_length = fdefaults->fat_length;
1598
1599         error = 0;
1600
1601 out:
1602         return error;
1603 }
1604
1605 /*
1606  * Read the super block of an MS-DOS FS.
1607  */
1608 int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
1609                    void (*setup)(struct super_block *))
1610 {
1611         struct inode *root_inode = NULL, *fat_inode = NULL;
1612         struct inode *fsinfo_inode = NULL;
1613         struct buffer_head *bh;
1614         struct fat_bios_param_block bpb;
1615         struct msdos_sb_info *sbi;
1616         u16 logical_sector_size;
1617         u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1618         int debug;
1619         long error;
1620         char buf[50];
1621
1622         /*
1623          * GFP_KERNEL is ok here, because while we do hold the
1624          * superblock lock, memory pressure can't call back into
1625          * the filesystem, since we're only just about to mount
1626          * it and have no inodes etc active!
1627          */
1628         sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1629         if (!sbi)
1630                 return -ENOMEM;
1631         sb->s_fs_info = sbi;
1632
1633         sb->s_flags |= SB_NODIRATIME;
1634         sb->s_magic = MSDOS_SUPER_MAGIC;
1635         sb->s_op = &fat_sops;
1636         sb->s_export_op = &fat_export_ops;
1637         mutex_init(&sbi->nfs_build_inode_lock);
1638         ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
1639                              DEFAULT_RATELIMIT_BURST);
1640
1641         error = parse_options(sb, data, isvfat, silent, &debug, &sbi->options);
1642         if (error)
1643                 goto out_fail;
1644
1645         setup(sb); /* flavour-specific stuff that needs options */
1646
1647         error = -EIO;
1648         sb_min_blocksize(sb, 512);
1649         bh = sb_bread(sb, 0);
1650         if (bh == NULL) {
1651                 fat_msg(sb, KERN_ERR, "unable to read boot sector");
1652                 goto out_fail;
1653         }
1654
1655         error = fat_read_bpb(sb, (struct fat_boot_sector *)bh->b_data, silent,
1656                 &bpb);
1657         if (error == -EINVAL && sbi->options.dos1xfloppy)
1658                 error = fat_read_static_bpb(sb,
1659                         (struct fat_boot_sector *)bh->b_data, silent, &bpb);
1660         brelse(bh);
1661
1662         if (error == -EINVAL)
1663                 goto out_invalid;
1664         else if (error)
1665                 goto out_fail;
1666
1667         logical_sector_size = bpb.fat_sector_size;
1668         sbi->sec_per_clus = bpb.fat_sec_per_clus;
1669
1670         error = -EIO;
1671         if (logical_sector_size < sb->s_blocksize) {
1672                 fat_msg(sb, KERN_ERR, "logical sector size too small for device"
1673                        " (logical sector size = %u)", logical_sector_size);
1674                 goto out_fail;
1675         }
1676
1677         if (logical_sector_size > sb->s_blocksize) {
1678                 struct buffer_head *bh_resize;
1679
1680                 if (!sb_set_blocksize(sb, logical_sector_size)) {
1681                         fat_msg(sb, KERN_ERR, "unable to set blocksize %u",
1682                                logical_sector_size);
1683                         goto out_fail;
1684                 }
1685
1686                 /* Verify that the larger boot sector is fully readable */
1687                 bh_resize = sb_bread(sb, 0);
1688                 if (bh_resize == NULL) {
1689                         fat_msg(sb, KERN_ERR, "unable to read boot sector"
1690                                " (logical sector size = %lu)",
1691                                sb->s_blocksize);
1692                         goto out_fail;
1693                 }
1694                 brelse(bh_resize);
1695         }
1696
1697         mutex_init(&sbi->s_lock);
1698         sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1699         sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1700         sbi->fats = bpb.fat_fats;
1701         sbi->fat_bits = 0;              /* Don't know yet */
1702         sbi->fat_start = bpb.fat_reserved;
1703         sbi->fat_length = bpb.fat_fat_length;
1704         sbi->root_cluster = 0;
1705         sbi->free_clusters = -1;        /* Don't know yet */
1706         sbi->free_clus_valid = 0;
1707         sbi->prev_free = FAT_START_ENT;
1708         sb->s_maxbytes = 0xffffffff;
1709
1710         if (!sbi->fat_length && bpb.fat32_length) {
1711                 struct fat_boot_fsinfo *fsinfo;
1712                 struct buffer_head *fsinfo_bh;
1713
1714                 /* Must be FAT32 */
1715                 sbi->fat_bits = 32;
1716                 sbi->fat_length = bpb.fat32_length;
1717                 sbi->root_cluster = bpb.fat32_root_cluster;
1718
1719                 /* MC - if info_sector is 0, don't multiply by 0 */
1720                 sbi->fsinfo_sector = bpb.fat32_info_sector;
1721                 if (sbi->fsinfo_sector == 0)
1722                         sbi->fsinfo_sector = 1;
1723
1724                 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1725                 if (fsinfo_bh == NULL) {
1726                         fat_msg(sb, KERN_ERR, "bread failed, FSINFO block"
1727                                " (sector = %lu)", sbi->fsinfo_sector);
1728                         goto out_fail;
1729                 }
1730
1731                 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1732                 if (!IS_FSINFO(fsinfo)) {
1733                         fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: "
1734                                "0x%08x, 0x%08x (sector = %lu)",
1735                                le32_to_cpu(fsinfo->signature1),
1736                                le32_to_cpu(fsinfo->signature2),
1737                                sbi->fsinfo_sector);
1738                 } else {
1739                         if (sbi->options.usefree)
1740                                 sbi->free_clus_valid = 1;
1741                         sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1742                         sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1743                 }
1744
1745                 brelse(fsinfo_bh);
1746         }
1747
1748         /* interpret volume ID as a little endian 32 bit integer */
1749         if (sbi->fat_bits == 32)
1750                 sbi->vol_id = bpb.fat32_vol_id;
1751         else /* fat 16 or 12 */
1752                 sbi->vol_id = bpb.fat16_vol_id;
1753
1754         sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1755         sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1756
1757         sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1758         sbi->dir_entries = bpb.fat_dir_entries;
1759         if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1760                 if (!silent)
1761                         fat_msg(sb, KERN_ERR, "bogus number of directory entries"
1762                                " (%u)", sbi->dir_entries);
1763                 goto out_invalid;
1764         }
1765
1766         rootdir_sectors = sbi->dir_entries
1767                 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1768         sbi->data_start = sbi->dir_start + rootdir_sectors;
1769         total_sectors = bpb.fat_sectors;
1770         if (total_sectors == 0)
1771                 total_sectors = bpb.fat_total_sect;
1772
1773         total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1774
1775         if (sbi->fat_bits != 32)
1776                 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1777
1778         /* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
1779         if (sbi->fat_bits == 32)
1780                 sbi->dirty = bpb.fat32_state & FAT_STATE_DIRTY;
1781         else /* fat 16 or 12 */
1782                 sbi->dirty = bpb.fat16_state & FAT_STATE_DIRTY;
1783
1784         /* check that FAT table does not overflow */
1785         fat_clusters = calc_fat_clusters(sb);
1786         total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1787         if (total_clusters > MAX_FAT(sb)) {
1788                 if (!silent)
1789                         fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
1790                                total_clusters);
1791                 goto out_invalid;
1792         }
1793
1794         sbi->max_cluster = total_clusters + FAT_START_ENT;
1795         /* check the free_clusters, it's not necessarily correct */
1796         if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1797                 sbi->free_clusters = -1;
1798         /* check the prev_free, it's not necessarily correct */
1799         sbi->prev_free %= sbi->max_cluster;
1800         if (sbi->prev_free < FAT_START_ENT)
1801                 sbi->prev_free = FAT_START_ENT;
1802
1803         /* set up enough so that it can read an inode */
1804         fat_hash_init(sb);
1805         dir_hash_init(sb);
1806         fat_ent_access_init(sb);
1807
1808         /*
1809          * The low byte of FAT's first entry must have same value with
1810          * media-field.  But in real world, too many devices is
1811          * writing wrong value.  So, removed that validity check.
1812          *
1813          * if (FAT_FIRST_ENT(sb, media) != first)
1814          */
1815
1816         error = -EINVAL;
1817         sprintf(buf, "cp%d", sbi->options.codepage);
1818         sbi->nls_disk = load_nls(buf);
1819         if (!sbi->nls_disk) {
1820                 fat_msg(sb, KERN_ERR, "codepage %s not found", buf);
1821                 goto out_fail;
1822         }
1823
1824         /* FIXME: utf8 is using iocharset for upper/lower conversion */
1825         if (sbi->options.isvfat) {
1826                 sbi->nls_io = load_nls(sbi->options.iocharset);
1827                 if (!sbi->nls_io) {
1828                         fat_msg(sb, KERN_ERR, "IO charset %s not found",
1829                                sbi->options.iocharset);
1830                         goto out_fail;
1831                 }
1832         }
1833
1834         error = -ENOMEM;
1835         fat_inode = new_inode(sb);
1836         if (!fat_inode)
1837                 goto out_fail;
1838         fat_dummy_inode_init(fat_inode);
1839         sbi->fat_inode = fat_inode;
1840
1841         fsinfo_inode = new_inode(sb);
1842         if (!fsinfo_inode)
1843                 goto out_fail;
1844         fat_dummy_inode_init(fsinfo_inode);
1845         fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
1846         sbi->fsinfo_inode = fsinfo_inode;
1847         insert_inode_hash(fsinfo_inode);
1848
1849         root_inode = new_inode(sb);
1850         if (!root_inode)
1851                 goto out_fail;
1852         root_inode->i_ino = MSDOS_ROOT_INO;
1853         inode_set_iversion(root_inode, 1);
1854         error = fat_read_root(root_inode);
1855         if (error < 0) {
1856                 iput(root_inode);
1857                 goto out_fail;
1858         }
1859         error = -ENOMEM;
1860         insert_inode_hash(root_inode);
1861         fat_attach(root_inode, 0);
1862         sb->s_root = d_make_root(root_inode);
1863         if (!sb->s_root) {
1864                 fat_msg(sb, KERN_ERR, "get root inode failed");
1865                 goto out_fail;
1866         }
1867
1868         if (sbi->options.discard) {
1869                 struct request_queue *q = bdev_get_queue(sb->s_bdev);
1870                 if (!blk_queue_discard(q))
1871                         fat_msg(sb, KERN_WARNING,
1872                                         "mounting with \"discard\" option, but "
1873                                         "the device does not support discard");
1874         }
1875
1876         fat_set_state(sb, 1, 0);
1877         return 0;
1878
1879 out_invalid:
1880         error = -EINVAL;
1881         if (!silent)
1882                 fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem");
1883
1884 out_fail:
1885         if (fsinfo_inode)
1886                 iput(fsinfo_inode);
1887         if (fat_inode)
1888                 iput(fat_inode);
1889         unload_nls(sbi->nls_io);
1890         unload_nls(sbi->nls_disk);
1891         fat_reset_iocharset(&sbi->options);
1892         sb->s_fs_info = NULL;
1893         kfree(sbi);
1894         return error;
1895 }
1896
1897 EXPORT_SYMBOL_GPL(fat_fill_super);
1898
1899 /*
1900  * helper function for fat_flush_inodes.  This writes both the inode
1901  * and the file data blocks, waiting for in flight data blocks before
1902  * the start of the call.  It does not wait for any io started
1903  * during the call
1904  */
1905 static int writeback_inode(struct inode *inode)
1906 {
1907
1908         int ret;
1909
1910         /* if we used wait=1, sync_inode_metadata waits for the io for the
1911         * inode to finish.  So wait=0 is sent down to sync_inode_metadata
1912         * and filemap_fdatawrite is used for the data blocks
1913         */
1914         ret = sync_inode_metadata(inode, 0);
1915         if (!ret)
1916                 ret = filemap_fdatawrite(inode->i_mapping);
1917         return ret;
1918 }
1919
1920 /*
1921  * write data and metadata corresponding to i1 and i2.  The io is
1922  * started but we do not wait for any of it to finish.
1923  *
1924  * filemap_flush is used for the block device, so if there is a dirty
1925  * page for a block already in flight, we will not wait and start the
1926  * io over again
1927  */
1928 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1929 {
1930         int ret = 0;
1931         if (!MSDOS_SB(sb)->options.flush)
1932                 return 0;
1933         if (i1)
1934                 ret = writeback_inode(i1);
1935         if (!ret && i2)
1936                 ret = writeback_inode(i2);
1937         if (!ret) {
1938                 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
1939                 ret = filemap_flush(mapping);
1940         }
1941         return ret;
1942 }
1943 EXPORT_SYMBOL_GPL(fat_flush_inodes);
1944
1945 static int __init init_fat_fs(void)
1946 {
1947         int err;
1948
1949         err = fat_cache_init();
1950         if (err)
1951                 return err;
1952
1953         err = fat_init_inodecache();
1954         if (err)
1955                 goto failed;
1956
1957         return 0;
1958
1959 failed:
1960         fat_cache_destroy();
1961         return err;
1962 }
1963
1964 static void __exit exit_fat_fs(void)
1965 {
1966         fat_cache_destroy();
1967         fat_destroy_inodecache();
1968 }
1969
1970 module_init(init_fat_fs)
1971 module_exit(exit_fat_fs)
1972
1973 MODULE_LICENSE("GPL");