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/init.h>
  15 #include <linux/time.h>
  16 #include <linux/slab.h>
  17 #include <linux/seq_file.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/mpage.h>
  20 #include <linux/buffer_head.h>
  21 #include <linux/mount.h>
  22 #include <linux/aio.h>
  23 #include <linux/vfs.h>
  24 #include <linux/parser.h>
  25 #include <linux/uio.h>
  26 #include <linux/writeback.h>
  27 #include <linux/log2.h>
  28 #include <linux/hash.h>
  29 #include <linux/blkdev.h>
  30 #include <asm/unaligned.h>
  31 #include "fat.h"
  32
  33 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET
  34 /* if user don't select VFAT, this is undefined. */
  35 #define CONFIG_FAT_DEFAULT_IOCHARSET    ""
  36 #endif
  37
  38 #define KB_IN_SECTORS 2
  39
  40 /*
  41  * A deserialized copy of the on-disk structure laid out in struct
  42  * fat_boot_sector.
  43  */
  44 struct fat_bios_param_block {
  45         u16     fat_sector_size;
  46         u8      fat_sec_per_clus;
  47         u16     fat_reserved;
  48         u8      fat_fats;
  49         u16     fat_dir_entries;
  50         u16     fat_sectors;
  51         u16     fat_fat_length;
  52         u32     fat_total_sect;
  53
  54         u8      fat16_state;
  55         u32     fat16_vol_id;
  56
  57         u32     fat32_length;
  58         u32     fat32_root_cluster;
  59         u16     fat32_info_sector;
  60         u8      fat32_state;
  61         u32     fat32_vol_id;
  62 };
  63
  64 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
  65 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
  66
  67 static struct fat_floppy_defaults {
  68         unsigned nr_sectors;
  69         unsigned sec_per_clus;
  70         unsigned dir_entries;
  71         unsigned media;
  72         unsigned fat_length;
  73 } floppy_defaults[] = {
  74 {
  75         .nr_sectors = 160 * KB_IN_SECTORS,
  76         .sec_per_clus = 1,
  77         .dir_entries = 64,
  78         .media = 0xFE,
  79         .fat_length = 1,
  80 },
  81 {
  82         .nr_sectors = 180 * KB_IN_SECTORS,
  83         .sec_per_clus = 1,
  84         .dir_entries = 64,
  85         .media = 0xFC,
  86         .fat_length = 2,
  87 },
  88 {
  89         .nr_sectors = 320 * KB_IN_SECTORS,
  90         .sec_per_clus = 2,
  91         .dir_entries = 112,
  92         .media = 0xFF,
  93         .fat_length = 1,
  94 },
  95 {
  96         .nr_sectors = 360 * KB_IN_SECTORS,
  97         .sec_per_clus = 2,
  98         .dir_entries = 112,
  99         .media = 0xFD,
 100         .fat_length = 2,
 101 },
 102 };
 103
 104 static int fat_add_cluster(struct inode *inode)
 105 {
 106         int err, cluster;
 107
 108         err = fat_alloc_clusters(inode, &cluster, 1);
 109         if (err)
 110                 return err;
 111         /* FIXME: this cluster should be added after data of this
 112          * cluster is writed */
 113         err = fat_chain_add(inode, cluster, 1);
 114         if (err)
 115                 fat_free_clusters(inode, cluster);
 116         return err;
 117 }
 118
 119 static void check_fallocated_region(struct inode *inode, sector_t iblock,
 120                 unsigned long *max_blocks, struct buffer_head *bh_result)
 121 {
 122         struct super_block *sb = inode->i_sb;
 123         sector_t last_block, disk_block;
 124         const unsigned long blocksize = sb->s_blocksize;
 125         const unsigned char blocksize_bits = sb->s_blocksize_bits;
 126
 127         last_block = (MSDOS_I(inode)->mmu_private + (blocksize - 1))
 128                 >> blocksize_bits;
 129         disk_block = (MSDOS_I(inode)->i_disksize + (blocksize - 1))
 130                 >> blocksize_bits;
 131         if (iblock >= last_block && iblock <= disk_block) {
 132                 MSDOS_I(inode)->mmu_private += *max_blocks << blocksize_bits;
 133                 set_buffer_new(bh_result);
 134         }
 135
 136 }
 137
 138 static inline int __fat_get_block(struct inode *inode, sector_t iblock,
 139                                   unsigned long *max_blocks,
 140                                   struct buffer_head *bh_result, int create)
 141 {
 142         struct super_block *sb = inode->i_sb;
 143         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 144         unsigned long mapped_blocks;
 145         sector_t phys;
 146         int err, offset;
 147
 148         err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
 149         if (err)
 150                 return err;
 151         if (phys) {
 152                 *max_blocks = min(mapped_blocks, *max_blocks);
 153                 if (create)
 154                         check_fallocated_region(inode, iblock, max_blocks,
 155                                 bh_result);
 156                 map_bh(bh_result, sb, phys);
 157                 return 0;
 158         }
 159         if (!create)
 160                 return 0;
 161
 162         if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
 163                 fat_fs_error(sb, "corrupted file size (i_pos %lld, %lld)",
 164                         MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
 165                 return -EIO;
 166         }
 167
 168         offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
 169         if (!offset) {
 170                 /* TODO: multiple cluster allocation would be desirable. */
 171                 err = fat_add_cluster(inode);
 172                 if (err)
 173                         return err;
 174         }
 175         /* available blocks on this cluster */
 176         mapped_blocks = sbi->sec_per_clus - offset;
 177
 178         *max_blocks = min(mapped_blocks, *max_blocks);
 179         MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
 180         MSDOS_I(inode)->i_disksize = MSDOS_I(inode)->mmu_private;
 181
 182         err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
 183         if (err)
 184                 return err;
 185
 186         BUG_ON(!phys);
 187         BUG_ON(*max_blocks != mapped_blocks);
 188         set_buffer_new(bh_result);
 189         map_bh(bh_result, sb, phys);
 190
 191         return 0;
 192 }
 193
 194 static int fat_get_block(struct inode *inode, sector_t iblock,
 195                          struct buffer_head *bh_result, int create)
 196 {
 197         struct super_block *sb = inode->i_sb;
 198         unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
 199         int err;
 200
 201         err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create);
 202         if (err)
 203                 return err;
 204         bh_result->b_size = max_blocks << sb->s_blocksize_bits;
 205         return 0;
 206 }
 207
 208 static int fat_writepage(struct page *page, struct writeback_control *wbc)
 209 {
 210         return block_write_full_page(page, fat_get_block, wbc);
 211 }
 212
 213 static int fat_writepages(struct address_space *mapping,
 214                           struct writeback_control *wbc)
 215 {
 216         return mpage_writepages(mapping, wbc, fat_get_block);
 217 }
 218
 219 static int fat_readpage(struct file *file, struct page *page)
 220 {
 221         return mpage_readpage(page, fat_get_block);
 222 }
 223
 224 static int fat_readpages(struct file *file, struct address_space *mapping,
 225                          struct list_head *pages, unsigned nr_pages)
 226 {
 227         return mpage_readpages(mapping, pages, nr_pages, fat_get_block);
 228 }
 229
 230 static void fat_write_failed(struct address_space *mapping, loff_t to)
 231 {
 232         struct inode *inode = mapping->host;
 233
 234         if (to > inode->i_size) {
 235                 truncate_pagecache(inode, inode->i_size);
 236                 fat_truncate_blocks(inode, inode->i_size);
 237         }
 238 }
 239
 240 static int fat_write_begin(struct file *file, struct address_space *mapping,
 241                         loff_t pos, unsigned len, unsigned flags,
 242                         struct page **pagep, void **fsdata)
 243 {
 244         int err;
 245
 246         *pagep = NULL;
 247         err = cont_write_begin(file, mapping, pos, len, flags,
 248                                 pagep, fsdata, fat_get_block,
 249                                 &MSDOS_I(mapping->host)->mmu_private);
 250         if (err < 0)
 251                 fat_write_failed(mapping, pos + len);
 252         return err;
 253 }
 254
 255 static int fat_write_end(struct file *file, struct address_space *mapping,
 256                         loff_t pos, unsigned len, unsigned copied,
 257                         struct page *pagep, void *fsdata)
 258 {
 259         struct inode *inode = mapping->host;
 260         int err;
 261         err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
 262         if (err < len)
 263                 fat_write_failed(mapping, pos + len);
 264         if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
 265                 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
 266                 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
 267                 mark_inode_dirty(inode);
 268         }
 269         return err;
 270 }
 271
 272 static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
 273                              struct iov_iter *iter,
 274                              loff_t offset)
 275 {
 276         struct file *file = iocb->ki_filp;
 277         struct address_space *mapping = file->f_mapping;
 278         struct inode *inode = mapping->host;
 279         size_t count = iov_iter_count(iter);
 280         ssize_t ret;
 281
 282         if (rw == WRITE) {
 283                 /*
 284                  * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
 285                  * so we need to update the ->mmu_private to block boundary.
 286                  *
 287                  * But we must fill the remaining area or hole by nul for
 288                  * updating ->mmu_private.
 289                  *
 290                  * Return 0, and fallback to normal buffered write.
 291                  */
 292                 loff_t size = offset + count;
 293                 if (MSDOS_I(inode)->mmu_private < size)
 294                         return 0;
 295
 296                 /*
 297                  * In case of writing in fallocated region, return 0 and
 298                  * fallback to buffered write.
 299                  */
 300                 if (MSDOS_I(inode)->i_disksize > MSDOS_I(inode)->mmu_private)
 301                         return 0;
 302         }
 303
 304         /*
 305          * FAT need to use the DIO_LOCKING for avoiding the race
 306          * condition of fat_get_block() and ->truncate().
 307          */
 308         ret = blockdev_direct_IO(rw, iocb, inode, iter, offset, fat_get_block);
 309         if (ret < 0 && (rw & WRITE))
 310                 fat_write_failed(mapping, offset + count);
 311
 312         return ret;
 313 }
 314
 315 static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
 316 {
 317         sector_t blocknr;
 318
 319         /* fat_get_cluster() assumes the requested blocknr isn't truncated. */
 320         down_read(&MSDOS_I(mapping->host)->truncate_lock);
 321         blocknr = generic_block_bmap(mapping, block, fat_get_block);
 322         up_read(&MSDOS_I(mapping->host)->truncate_lock);
 323
 324         return blocknr;
 325 }
 326
 327 static const struct address_space_operations fat_aops = {
 328         .readpage       = fat_readpage,
 329         .readpages      = fat_readpages,
 330         .writepage      = fat_writepage,
 331         .writepages     = fat_writepages,
 332         .write_begin    = fat_write_begin,
 333         .write_end      = fat_write_end,
 334         .direct_IO      = fat_direct_IO,
 335         .bmap           = _fat_bmap
 336 };
 337
 338 /*
 339  * New FAT inode stuff. We do the following:
 340  *      a) i_ino is constant and has nothing with on-disk location.
 341  *      b) FAT manages its own cache of directory entries.
 342  *      c) *This* cache is indexed by on-disk location.
 343  *      d) inode has an associated directory entry, all right, but
 344  *              it may be unhashed.
 345  *      e) currently entries are stored within struct inode. That should
 346  *              change.
 347  *      f) we deal with races in the following way:
 348  *              1. readdir() and lookup() do FAT-dir-cache lookup.
 349  *              2. rename() unhashes the F-d-c entry and rehashes it in
 350  *                      a new place.
 351  *              3. unlink() and rmdir() unhash F-d-c entry.
 352  *              4. fat_write_inode() checks whether the thing is unhashed.
 353  *                      If it is we silently return. If it isn't we do bread(),
 354  *                      check if the location is still valid and retry if it
 355  *                      isn't. Otherwise we do changes.
 356  *              5. Spinlock is used to protect hash/unhash/location check/lookup
 357  *              6. fat_evict_inode() unhashes the F-d-c entry.
 358  *              7. lookup() and readdir() do igrab() if they find a F-d-c entry
 359  *                      and consider negative result as cache miss.
 360  */
 361
 362 static void fat_hash_init(struct super_block *sb)
 363 {
 364         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 365         int i;
 366
 367         spin_lock_init(&sbi->inode_hash_lock);
 368         for (i = 0; i < FAT_HASH_SIZE; i++)
 369                 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
 370 }
 371
 372 static inline unsigned long fat_hash(loff_t i_pos)
 373 {
 374         return hash_32(i_pos, FAT_HASH_BITS);
 375 }
 376
 377 static void dir_hash_init(struct super_block *sb)
 378 {
 379         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 380         int i;
 381
 382         spin_lock_init(&sbi->dir_hash_lock);
 383         for (i = 0; i < FAT_HASH_SIZE; i++)
 384                 INIT_HLIST_HEAD(&sbi->dir_hashtable[i]);
 385 }
 386
 387 void fat_attach(struct inode *inode, loff_t i_pos)
 388 {
 389         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
 390
 391         if (inode->i_ino != MSDOS_ROOT_INO) {
 392                 struct hlist_head *head =   sbi->inode_hashtable
 393                                           + fat_hash(i_pos);
 394
 395                 spin_lock(&sbi->inode_hash_lock);
 396                 MSDOS_I(inode)->i_pos = i_pos;
 397                 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
 398                 spin_unlock(&sbi->inode_hash_lock);
 399         }
 400
 401         /* If NFS support is enabled, cache the mapping of start cluster
 402          * to directory inode. This is used during reconnection of
 403          * dentries to the filesystem root.
 404          */
 405         if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
 406                 struct hlist_head *d_head = sbi->dir_hashtable;
 407                 d_head += fat_dir_hash(MSDOS_I(inode)->i_logstart);
 408
 409                 spin_lock(&sbi->dir_hash_lock);
 410                 hlist_add_head(&MSDOS_I(inode)->i_dir_hash, d_head);
 411                 spin_unlock(&sbi->dir_hash_lock);
 412         }
 413 }
 414 EXPORT_SYMBOL_GPL(fat_attach);
 415
 416 void fat_detach(struct inode *inode)
 417 {
 418         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
 419         spin_lock(&sbi->inode_hash_lock);
 420         MSDOS_I(inode)->i_pos = 0;
 421         hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
 422         spin_unlock(&sbi->inode_hash_lock);
 423
 424         if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
 425                 spin_lock(&sbi->dir_hash_lock);
 426                 hlist_del_init(&MSDOS_I(inode)->i_dir_hash);
 427                 spin_unlock(&sbi->dir_hash_lock);
 428         }
 429 }
 430 EXPORT_SYMBOL_GPL(fat_detach);
 431
 432 struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
 433 {
 434         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 435         struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
 436         struct msdos_inode_info *i;
 437         struct inode *inode = NULL;
 438
 439         spin_lock(&sbi->inode_hash_lock);
 440         hlist_for_each_entry(i, head, i_fat_hash) {
 441                 BUG_ON(i->vfs_inode.i_sb != sb);
 442                 if (i->i_pos != i_pos)
 443                         continue;
 444                 inode = igrab(&i->vfs_inode);
 445                 if (inode)
 446                         break;
 447         }
 448         spin_unlock(&sbi->inode_hash_lock);
 449         return inode;
 450 }
 451
 452 static int is_exec(unsigned char *extension)
 453 {
 454         unsigned char exe_extensions[] = "EXECOMBAT", *walk;
 455
 456         for (walk = exe_extensions; *walk; walk += 3)
 457                 if (!strncmp(extension, walk, 3))
 458                         return 1;
 459         return 0;
 460 }
 461
 462 static int fat_calc_dir_size(struct inode *inode)
 463 {
 464         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
 465         int ret, fclus, dclus;
 466
 467         inode->i_size = 0;
 468         if (MSDOS_I(inode)->i_start == 0)
 469                 return 0;
 470
 471         ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
 472         if (ret < 0)
 473                 return ret;
 474         inode->i_size = (fclus + 1) << sbi->cluster_bits;
 475
 476         return 0;
 477 }
 478
 479 /* doesn't deal with root inode */
 480 int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
 481 {
 482         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
 483         int error;
 484
 485         MSDOS_I(inode)->i_pos = 0;
 486         inode->i_uid = sbi->options.fs_uid;
 487         inode->i_gid = sbi->options.fs_gid;
 488         inode->i_version++;
 489         inode->i_generation = get_seconds();
 490
 491         if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
 492                 inode->i_generation &= ~1;
 493                 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
 494                 inode->i_op = sbi->dir_ops;
 495                 inode->i_fop = &fat_dir_operations;
 496
 497                 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
 498                 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
 499                 error = fat_calc_dir_size(inode);
 500                 if (error < 0)
 501                         return error;
 502
 503                 set_nlink(inode, fat_subdirs(inode));
 504         } else { /* not a directory */
 505                 inode->i_generation |= 1;
 506                 inode->i_mode = fat_make_mode(sbi, de->attr,
 507                         ((sbi->options.showexec && !is_exec(de->name + 8))
 508                          ? S_IRUGO|S_IWUGO : S_IRWXUGO));
 509                 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
 510
 511                 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
 512                 inode->i_size = le32_to_cpu(de->size);
 513                 inode->i_op = &fat_file_inode_operations;
 514                 inode->i_fop = &fat_file_operations;
 515                 inode->i_mapping->a_ops = &fat_aops;
 516         }
 517
 518         MSDOS_I(inode)->mmu_private = inode->i_size;
 519         MSDOS_I(inode)->i_disksize = round_up(inode->i_size,
 520                 inode->i_sb->s_blocksize);
 521
 522         if (de->attr & ATTR_SYS) {
 523                 if (sbi->options.sys_immutable)
 524                         inode->i_flags |= S_IMMUTABLE;
 525         }
 526         fat_save_attrs(inode, de->attr);
 527
 528         inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
 529                            & ~((loff_t)sbi->cluster_size - 1)) >> 9;
 530
 531         fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0);
 532         if (sbi->options.isvfat) {
 533                 fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime,
 534                                   de->cdate, de->ctime_cs);
 535                 fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
 536         } else
 537                 inode->i_ctime = inode->i_atime = inode->i_mtime;
 538
 539         return 0;
 540 }
 541
 542 static inline void fat_lock_build_inode(struct msdos_sb_info *sbi)
 543 {
 544         if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
 545                 mutex_lock(&sbi->nfs_build_inode_lock);
 546 }
 547
 548 static inline void fat_unlock_build_inode(struct msdos_sb_info *sbi)
 549 {
 550         if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
 551                 mutex_unlock(&sbi->nfs_build_inode_lock);
 552 }
 553
 554 struct inode *fat_build_inode(struct super_block *sb,
 555                         struct msdos_dir_entry *de, loff_t i_pos)
 556 {
 557         struct inode *inode;
 558         int err;
 559
 560         fat_lock_build_inode(MSDOS_SB(sb));
 561         inode = fat_iget(sb, i_pos);
 562         if (inode)
 563                 goto out;
 564         inode = new_inode(sb);
 565         if (!inode) {
 566                 inode = ERR_PTR(-ENOMEM);
 567                 goto out;
 568         }
 569         inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
 570         inode->i_version = 1;
 571         err = fat_fill_inode(inode, de);
 572         if (err) {
 573                 iput(inode);
 574                 inode = ERR_PTR(err);
 575                 goto out;
 576         }
 577         fat_attach(inode, i_pos);
 578         insert_inode_hash(inode);
 579 out:
 580         fat_unlock_build_inode(MSDOS_SB(sb));
 581         return inode;
 582 }
 583
 584 EXPORT_SYMBOL_GPL(fat_build_inode);
 585
 586 static int __fat_write_inode(struct inode *inode, int wait);
 587 static void fat_evict_inode(struct inode *inode)
 588 {
 589         truncate_inode_pages_final(&inode->i_data);
 590         if (!inode->i_nlink) {
 591                 inode->i_size = 0;
 592                 fat_truncate_blocks(inode, 0);
 593         } else {
 594                 /* Release unwritten fallocated blocks on inode eviction. */
 595                 if (MSDOS_I(inode)->i_disksize >
 596                     round_up(MSDOS_I(inode)->mmu_private,
 597                                 inode->i_sb->s_blocksize)) {
 598                         int err;
 599                         fat_truncate_blocks(inode, MSDOS_I(inode)->mmu_private);
 600                         /* Fallocate results in updating the i_start/iogstart
 601                          * for the zero byte file. So, make it return to
 602                          * original state during evict and commit it to avoid
 603                          * any corruption on the next access to the cluster
 604                          * chain for the file.
 605                          */
 606                         err = __fat_write_inode(inode, inode_needs_sync(inode));
 607                         if (err) {
 608                                 fat_msg(inode->i_sb, KERN_WARNING, "Failed to "
 609                                 "update on disk inode for unused fallocated "
 610                                 "blocks, inode could be corrupted. Please run "
 611                                 "fsck");
 612                         }
 613                 }
 614         }
 615         invalidate_inode_buffers(inode);
 616         clear_inode(inode);
 617         fat_cache_inval_inode(inode);
 618         fat_detach(inode);
 619 }
 620
 621 static void fat_set_state(struct super_block *sb,
 622                         unsigned int set, unsigned int force)
 623 {
 624         struct buffer_head *bh;
 625         struct fat_boot_sector *b;
 626         struct msdos_sb_info *sbi = sb->s_fs_info;
 627
 628         /* do not change any thing if mounted read only */
 629         if ((sb->s_flags & MS_RDONLY) && !force)
 630                 return;
 631
 632         /* do not change state if fs was dirty */
 633         if (sbi->dirty) {
 634                 /* warn only on set (mount). */
 635                 if (set)
 636                         fat_msg(sb, KERN_WARNING, "Volume was not properly "
 637                                 "unmounted. Some data may be corrupt. "
 638                                 "Please run fsck.");
 639                 return;
 640         }
 641
 642         bh = sb_bread(sb, 0);
 643         if (bh == NULL) {
 644                 fat_msg(sb, KERN_ERR, "unable to read boot sector "
 645                         "to mark fs as dirty");
 646                 return;
 647         }
 648
 649         b = (struct fat_boot_sector *) bh->b_data;
 650
 651         if (sbi->fat_bits == 32) {
 652                 if (set)
 653                         b->fat32.state |= FAT_STATE_DIRTY;
 654                 else
 655                         b->fat32.state &= ~FAT_STATE_DIRTY;
 656         } else /* fat 16 and 12 */ {
 657                 if (set)
 658                         b->fat16.state |= FAT_STATE_DIRTY;
 659                 else
 660                         b->fat16.state &= ~FAT_STATE_DIRTY;
 661         }
 662
 663         mark_buffer_dirty(bh);
 664         sync_dirty_buffer(bh);
 665         brelse(bh);
 666 }
 667
 668 static void delayed_free(struct rcu_head *p)
 669 {
 670         struct msdos_sb_info *sbi = container_of(p, struct msdos_sb_info, rcu);
 671         unload_nls(sbi->nls_disk);
 672         unload_nls(sbi->nls_io);
 673         if (sbi->options.iocharset != fat_default_iocharset)
 674                 kfree(sbi->options.iocharset);
 675         kfree(sbi);
 676 }
 677
 678 static void fat_put_super(struct super_block *sb)
 679 {
 680         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 681
 682         fat_set_state(sb, 0, 0);
 683
 684         iput(sbi->fsinfo_inode);
 685         iput(sbi->fat_inode);
 686
 687         call_rcu(&sbi->rcu, delayed_free);
 688 }
 689
 690 static struct kmem_cache *fat_inode_cachep;
 691
 692 static struct inode *fat_alloc_inode(struct super_block *sb)
 693 {
 694         struct msdos_inode_info *ei;
 695         ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
 696         if (!ei)
 697                 return NULL;
 698
 699         init_rwsem(&ei->truncate_lock);
 700         return &ei->vfs_inode;
 701 }
 702
 703 static void fat_i_callback(struct rcu_head *head)
 704 {
 705         struct inode *inode = container_of(head, struct inode, i_rcu);
 706         kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
 707 }
 708
 709 static void fat_destroy_inode(struct inode *inode)
 710 {
 711         call_rcu(&inode->i_rcu, fat_i_callback);
 712 }
 713
 714 static void init_once(void *foo)
 715 {
 716         struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
 717
 718         spin_lock_init(&ei->cache_lru_lock);
 719         ei->nr_caches = 0;
 720         ei->cache_valid_id = FAT_CACHE_VALID + 1;
 721         INIT_LIST_HEAD(&ei->cache_lru);
 722         INIT_HLIST_NODE(&ei->i_fat_hash);
 723         INIT_HLIST_NODE(&ei->i_dir_hash);
 724         inode_init_once(&ei->vfs_inode);
 725 }
 726
 727 static int __init fat_init_inodecache(void)
 728 {
 729         fat_inode_cachep = kmem_cache_create("fat_inode_cache",
 730                                              sizeof(struct msdos_inode_info),
 731                                              0, (SLAB_RECLAIM_ACCOUNT|
 732                                                 SLAB_MEM_SPREAD),
 733                                              init_once);
 734         if (fat_inode_cachep == NULL)
 735                 return -ENOMEM;
 736         return 0;
 737 }
 738
 739 static void __exit fat_destroy_inodecache(void)
 740 {
 741         /*
 742          * Make sure all delayed rcu free inodes are flushed before we
 743          * destroy cache.
 744          */
 745         rcu_barrier();
 746         kmem_cache_destroy(fat_inode_cachep);
 747 }
 748
 749 static int fat_remount(struct super_block *sb, int *flags, char *data)
 750 {
 751         int new_rdonly;
 752         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 753         *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME);
 754
 755         sync_filesystem(sb);
 756
 757         /* make sure we update state on remount. */
 758         new_rdonly = *flags & MS_RDONLY;
 759         if (new_rdonly != (sb->s_flags & MS_RDONLY)) {
 760                 if (new_rdonly)
 761                         fat_set_state(sb, 0, 0);
 762                 else
 763                         fat_set_state(sb, 1, 1);
 764         }
 765         return 0;
 766 }
 767
 768 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
 769 {
 770         struct super_block *sb = dentry->d_sb;
 771         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 772         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 773
 774         /* If the count of free cluster is still unknown, counts it here. */
 775         if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
 776                 int err = fat_count_free_clusters(dentry->d_sb);
 777                 if (err)
 778                         return err;
 779         }
 780
 781         buf->f_type = dentry->d_sb->s_magic;
 782         buf->f_bsize = sbi->cluster_size;
 783         buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
 784         buf->f_bfree = sbi->free_clusters;
 785         buf->f_bavail = sbi->free_clusters;
 786         buf->f_fsid.val[0] = (u32)id;
 787         buf->f_fsid.val[1] = (u32)(id >> 32);
 788         buf->f_namelen =
 789                 (sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE;
 790
 791         return 0;
 792 }
 793
 794 static int __fat_write_inode(struct inode *inode, int wait)
 795 {
 796         struct super_block *sb = inode->i_sb;
 797         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 798         struct buffer_head *bh;
 799         struct msdos_dir_entry *raw_entry;
 800         loff_t i_pos;
 801         sector_t blocknr;
 802         int err, offset;
 803
 804         if (inode->i_ino == MSDOS_ROOT_INO)
 805                 return 0;
 806
 807 retry:
 808         i_pos = fat_i_pos_read(sbi, inode);
 809         if (!i_pos)
 810                 return 0;
 811
 812         fat_get_blknr_offset(sbi, i_pos, &blocknr, &offset);
 813         bh = sb_bread(sb, blocknr);
 814         if (!bh) {
 815                 fat_msg(sb, KERN_ERR, "unable to read inode block "
 816                        "for updating (i_pos %lld)", i_pos);
 817                 return -EIO;
 818         }
 819         spin_lock(&sbi->inode_hash_lock);
 820         if (i_pos != MSDOS_I(inode)->i_pos) {
 821                 spin_unlock(&sbi->inode_hash_lock);
 822                 brelse(bh);
 823                 goto retry;
 824         }
 825
 826         raw_entry = &((struct msdos_dir_entry *) (bh->b_data))[offset];
 827         if (S_ISDIR(inode->i_mode))
 828                 raw_entry->size = 0;
 829         else
 830                 raw_entry->size = cpu_to_le32(inode->i_size);
 831         raw_entry->attr = fat_make_attrs(inode);
 832         fat_set_start(raw_entry, MSDOS_I(inode)->i_logstart);
 833         fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
 834                           &raw_entry->date, NULL);
 835         if (sbi->options.isvfat) {
 836                 __le16 atime;
 837                 fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime,
 838                                   &raw_entry->cdate, &raw_entry->ctime_cs);
 839                 fat_time_unix2fat(sbi, &inode->i_atime, &atime,
 840                                   &raw_entry->adate, NULL);
 841         }
 842         spin_unlock(&sbi->inode_hash_lock);
 843         mark_buffer_dirty(bh);
 844         err = 0;
 845         if (wait)
 846                 err = sync_dirty_buffer(bh);
 847         brelse(bh);
 848         return err;
 849 }
 850
 851 static int fat_write_inode(struct inode *inode, struct writeback_control *wbc)
 852 {
 853         int err;
 854
 855         if (inode->i_ino == MSDOS_FSINFO_INO) {
 856                 struct super_block *sb = inode->i_sb;
 857
 858                 mutex_lock(&MSDOS_SB(sb)->s_lock);
 859                 err = fat_clusters_flush(sb);
 860                 mutex_unlock(&MSDOS_SB(sb)->s_lock);
 861         } else
 862                 err = __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
 863
 864         return err;
 865 }
 866
 867 int fat_sync_inode(struct inode *inode)
 868 {
 869         return __fat_write_inode(inode, 1);
 870 }
 871
 872 EXPORT_SYMBOL_GPL(fat_sync_inode);
 873
 874 static int fat_show_options(struct seq_file *m, struct dentry *root);
 875 static const struct super_operations fat_sops = {
 876         .alloc_inode    = fat_alloc_inode,
 877         .destroy_inode  = fat_destroy_inode,
 878         .write_inode    = fat_write_inode,
 879         .evict_inode    = fat_evict_inode,
 880         .put_super      = fat_put_super,
 881         .statfs         = fat_statfs,
 882         .remount_fs     = fat_remount,
 883
 884         .show_options   = fat_show_options,
 885 };
 886
 887 static int fat_show_options(struct seq_file *m, struct dentry *root)
 888 {
 889         struct msdos_sb_info *sbi = MSDOS_SB(root->d_sb);
 890         struct fat_mount_options *opts = &sbi->options;
 891         int isvfat = opts->isvfat;
 892
 893         if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
 894                 seq_printf(m, ",uid=%u",
 895                                 from_kuid_munged(&init_user_ns, opts->fs_uid));
 896         if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
 897                 seq_printf(m, ",gid=%u",
 898                                 from_kgid_munged(&init_user_ns, opts->fs_gid));
 899         seq_printf(m, ",fmask=%04o", opts->fs_fmask);
 900         seq_printf(m, ",dmask=%04o", opts->fs_dmask);
 901         if (opts->allow_utime)
 902                 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
 903         if (sbi->nls_disk)
 904                 /* strip "cp" prefix from displayed option */
 905                 seq_printf(m, ",codepage=%s", &sbi->nls_disk->charset[2]);
 906         if (isvfat) {
 907                 if (sbi->nls_io)
 908                         seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
 909
 910                 switch (opts->shortname) {
 911                 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
 912                         seq_puts(m, ",shortname=win95");
 913                         break;
 914                 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
 915                         seq_puts(m, ",shortname=winnt");
 916                         break;
 917                 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
 918                         seq_puts(m, ",shortname=mixed");
 919                         break;
 920                 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
 921                         seq_puts(m, ",shortname=lower");
 922                         break;
 923                 default:
 924                         seq_puts(m, ",shortname=unknown");
 925                         break;
 926                 }
 927         }
 928         if (opts->name_check != 'n')
 929                 seq_printf(m, ",check=%c", opts->name_check);
 930         if (opts->usefree)
 931                 seq_puts(m, ",usefree");
 932         if (opts->quiet)
 933                 seq_puts(m, ",quiet");
 934         if (opts->showexec)
 935                 seq_puts(m, ",showexec");
 936         if (opts->sys_immutable)
 937                 seq_puts(m, ",sys_immutable");
 938         if (!isvfat) {
 939                 if (opts->dotsOK)
 940                         seq_puts(m, ",dotsOK=yes");
 941                 if (opts->nocase)
 942                         seq_puts(m, ",nocase");
 943         } else {
 944                 if (opts->utf8)
 945                         seq_puts(m, ",utf8");
 946                 if (opts->unicode_xlate)
 947                         seq_puts(m, ",uni_xlate");
 948                 if (!opts->numtail)
 949                         seq_puts(m, ",nonumtail");
 950                 if (opts->rodir)
 951                         seq_puts(m, ",rodir");
 952         }
 953         if (opts->flush)
 954                 seq_puts(m, ",flush");
 955         if (opts->tz_set) {
 956                 if (opts->time_offset)
 957                         seq_printf(m, ",time_offset=%d", opts->time_offset);
 958                 else
 959                         seq_puts(m, ",tz=UTC");
 960         }
 961         if (opts->errors == FAT_ERRORS_CONT)
 962                 seq_puts(m, ",errors=continue");
 963         else if (opts->errors == FAT_ERRORS_PANIC)
 964                 seq_puts(m, ",errors=panic");
 965         else
 966                 seq_puts(m, ",errors=remount-ro");
 967         if (opts->nfs == FAT_NFS_NOSTALE_RO)
 968                 seq_puts(m, ",nfs=nostale_ro");
 969         else if (opts->nfs)
 970                 seq_puts(m, ",nfs=stale_rw");
 971         if (opts->discard)
 972                 seq_puts(m, ",discard");
 973         if (opts->dos1xfloppy)
 974                 seq_puts(m, ",dos1xfloppy");
 975
 976         return 0;
 977 }
 978
 979 enum {
 980         Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
 981         Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
 982         Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
 983         Opt_immutable, Opt_dots, Opt_nodots,
 984         Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
 985         Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
 986         Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
 987         Opt_obsolete, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
 988         Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_time_offset,
 989         Opt_nfs_stale_rw, Opt_nfs_nostale_ro, Opt_err, Opt_dos1xfloppy,
 990 };
 991
 992 static const match_table_t fat_tokens = {
 993         {Opt_check_r, "check=relaxed"},
 994         {Opt_check_s, "check=strict"},
 995         {Opt_check_n, "check=normal"},
 996         {Opt_check_r, "check=r"},
 997         {Opt_check_s, "check=s"},
 998         {Opt_check_n, "check=n"},
 999         {Opt_uid, "uid=%u"},
1000         {Opt_gid, "gid=%u"},
1001         {Opt_umask, "umask=%o"},
1002         {Opt_dmask, "dmask=%o"},
1003         {Opt_fmask, "fmask=%o"},
1004         {Opt_allow_utime, "allow_utime=%o"},
1005         {Opt_codepage, "codepage=%u"},
1006         {Opt_usefree, "usefree"},
1007         {Opt_nocase, "nocase"},
1008         {Opt_quiet, "quiet"},
1009         {Opt_showexec, "showexec"},
1010         {Opt_debug, "debug"},
1011         {Opt_immutable, "sys_immutable"},
1012         {Opt_flush, "flush"},
1013         {Opt_tz_utc, "tz=UTC"},
1014         {Opt_time_offset, "time_offset=%d"},
1015         {Opt_err_cont, "errors=continue"},
1016         {Opt_err_panic, "errors=panic"},
1017         {Opt_err_ro, "errors=remount-ro"},
1018         {Opt_discard, "discard"},
1019         {Opt_nfs_stale_rw, "nfs"},
1020         {Opt_nfs_stale_rw, "nfs=stale_rw"},
1021         {Opt_nfs_nostale_ro, "nfs=nostale_ro"},
1022         {Opt_dos1xfloppy, "dos1xfloppy"},
1023         {Opt_obsolete, "conv=binary"},
1024         {Opt_obsolete, "conv=text"},
1025         {Opt_obsolete, "conv=auto"},
1026         {Opt_obsolete, "conv=b"},
1027         {Opt_obsolete, "conv=t"},
1028         {Opt_obsolete, "conv=a"},
1029         {Opt_obsolete, "fat=%u"},
1030         {Opt_obsolete, "blocksize=%u"},
1031         {Opt_obsolete, "cvf_format=%20s"},
1032         {Opt_obsolete, "cvf_options=%100s"},
1033         {Opt_obsolete, "posix"},
1034         {Opt_err, NULL},
1035 };
1036 static const match_table_t msdos_tokens = {
1037         {Opt_nodots, "nodots"},
1038         {Opt_nodots, "dotsOK=no"},
1039         {Opt_dots, "dots"},
1040         {Opt_dots, "dotsOK=yes"},
1041         {Opt_err, NULL}
1042 };
1043 static const match_table_t vfat_tokens = {
1044         {Opt_charset, "iocharset=%s"},
1045         {Opt_shortname_lower, "shortname=lower"},
1046         {Opt_shortname_win95, "shortname=win95"},
1047         {Opt_shortname_winnt, "shortname=winnt"},
1048         {Opt_shortname_mixed, "shortname=mixed"},
1049         {Opt_utf8_no, "utf8=0"},                /* 0 or no or false */
1050         {Opt_utf8_no, "utf8=no"},
1051         {Opt_utf8_no, "utf8=false"},
1052         {Opt_utf8_yes, "utf8=1"},               /* empty or 1 or yes or true */
1053         {Opt_utf8_yes, "utf8=yes"},
1054         {Opt_utf8_yes, "utf8=true"},
1055         {Opt_utf8_yes, "utf8"},
1056         {Opt_uni_xl_no, "uni_xlate=0"},         /* 0 or no or false */
1057         {Opt_uni_xl_no, "uni_xlate=no"},
1058         {Opt_uni_xl_no, "uni_xlate=false"},
1059         {Opt_uni_xl_yes, "uni_xlate=1"},        /* empty or 1 or yes or true */
1060         {Opt_uni_xl_yes, "uni_xlate=yes"},
1061         {Opt_uni_xl_yes, "uni_xlate=true"},
1062         {Opt_uni_xl_yes, "uni_xlate"},
1063         {Opt_nonumtail_no, "nonumtail=0"},      /* 0 or no or false */
1064         {Opt_nonumtail_no, "nonumtail=no"},
1065         {Opt_nonumtail_no, "nonumtail=false"},
1066         {Opt_nonumtail_yes, "nonumtail=1"},     /* empty or 1 or yes or true */
1067         {Opt_nonumtail_yes, "nonumtail=yes"},
1068         {Opt_nonumtail_yes, "nonumtail=true"},
1069         {Opt_nonumtail_yes, "nonumtail"},
1070         {Opt_rodir, "rodir"},
1071         {Opt_err, NULL}
1072 };
1073
1074 static int parse_options(struct super_block *sb, char *options, int is_vfat,
1075                          int silent, int *debug, struct fat_mount_options *opts)
1076 {
1077         char *p;
1078         substring_t args[MAX_OPT_ARGS];
1079         int option;
1080         char *iocharset;
1081
1082         opts->isvfat = is_vfat;
1083
1084         opts->fs_uid = current_uid();
1085         opts->fs_gid = current_gid();
1086         opts->fs_fmask = opts->fs_dmask = current_umask();
1087         opts->allow_utime = -1;
1088         opts->codepage = fat_default_codepage;
1089         opts->iocharset = fat_default_iocharset;
1090         if (is_vfat) {
1091                 opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95;
1092                 opts->rodir = 0;
1093         } else {
1094                 opts->shortname = 0;
1095                 opts->rodir = 1;
1096         }
1097         opts->name_check = 'n';
1098         opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK =  0;
1099         opts->utf8 = opts->unicode_xlate = 0;
1100         opts->numtail = 1;
1101         opts->usefree = opts->nocase = 0;
1102         opts->tz_set = 0;
1103         opts->nfs = 0;
1104         opts->errors = FAT_ERRORS_RO;
1105         *debug = 0;
1106
1107         if (!options)
1108                 goto out;
1109
1110         while ((p = strsep(&options, ",")) != NULL) {
1111                 int token;
1112                 if (!*p)
1113                         continue;
1114
1115                 token = match_token(p, fat_tokens, args);
1116                 if (token == Opt_err) {
1117                         if (is_vfat)
1118                                 token = match_token(p, vfat_tokens, args);
1119                         else
1120                                 token = match_token(p, msdos_tokens, args);
1121                 }
1122                 switch (token) {
1123                 case Opt_check_s:
1124                         opts->name_check = 's';
1125                         break;
1126                 case Opt_check_r:
1127                         opts->name_check = 'r';
1128                         break;
1129                 case Opt_check_n:
1130                         opts->name_check = 'n';
1131                         break;
1132                 case Opt_usefree:
1133                         opts->usefree = 1;
1134                         break;
1135                 case Opt_nocase:
1136                         if (!is_vfat)
1137                                 opts->nocase = 1;
1138                         else {
1139                                 /* for backward compatibility */
1140                                 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1141                                         | VFAT_SFN_CREATE_WIN95;
1142                         }
1143                         break;
1144                 case Opt_quiet:
1145                         opts->quiet = 1;
1146                         break;
1147                 case Opt_showexec:
1148                         opts->showexec = 1;
1149                         break;
1150                 case Opt_debug:
1151                         *debug = 1;
1152                         break;
1153                 case Opt_immutable:
1154                         opts->sys_immutable = 1;
1155                         break;
1156                 case Opt_uid:
1157                         if (match_int(&args[0], &option))
1158                                 return -EINVAL;
1159                         opts->fs_uid = make_kuid(current_user_ns(), option);
1160                         if (!uid_valid(opts->fs_uid))
1161                                 return -EINVAL;
1162                         break;
1163                 case Opt_gid:
1164                         if (match_int(&args[0], &option))
1165                                 return -EINVAL;
1166                         opts->fs_gid = make_kgid(current_user_ns(), option);
1167                         if (!gid_valid(opts->fs_gid))
1168                                 return -EINVAL;
1169                         break;
1170                 case Opt_umask:
1171                         if (match_octal(&args[0], &option))
1172                                 return -EINVAL;
1173                         opts->fs_fmask = opts->fs_dmask = option;
1174                         break;
1175                 case Opt_dmask:
1176                         if (match_octal(&args[0], &option))
1177                                 return -EINVAL;
1178                         opts->fs_dmask = option;
1179                         break;
1180                 case Opt_fmask:
1181                         if (match_octal(&args[0], &option))
1182                                 return -EINVAL;
1183                         opts->fs_fmask = option;
1184                         break;
1185                 case Opt_allow_utime:
1186                         if (match_octal(&args[0], &option))
1187                                 return -EINVAL;
1188                         opts->allow_utime = option & (S_IWGRP | S_IWOTH);
1189                         break;
1190                 case Opt_codepage:
1191                         if (match_int(&args[0], &option))
1192                                 return -EINVAL;
1193                         opts->codepage = option;
1194                         break;
1195                 case Opt_flush:
1196                         opts->flush = 1;
1197                         break;
1198                 case Opt_time_offset:
1199                         if (match_int(&args[0], &option))
1200                                 return -EINVAL;
1201                         if (option < -12 * 60 || option > 12 * 60)
1202                                 return -EINVAL;
1203                         opts->tz_set = 1;
1204                         opts->time_offset = option;
1205                         break;
1206                 case Opt_tz_utc:
1207                         opts->tz_set = 1;
1208                         opts->time_offset = 0;
1209                         break;
1210                 case Opt_err_cont:
1211                         opts->errors = FAT_ERRORS_CONT;
1212                         break;
1213                 case Opt_err_panic:
1214                         opts->errors = FAT_ERRORS_PANIC;
1215                         break;
1216                 case Opt_err_ro:
1217                         opts->errors = FAT_ERRORS_RO;
1218                         break;
1219                 case Opt_nfs_stale_rw:
1220                         opts->nfs = FAT_NFS_STALE_RW;
1221                         break;
1222                 case Opt_nfs_nostale_ro:
1223                         opts->nfs = FAT_NFS_NOSTALE_RO;
1224                         break;
1225                 case Opt_dos1xfloppy:
1226                         opts->dos1xfloppy = 1;
1227                         break;
1228
1229                 /* msdos specific */
1230                 case Opt_dots:
1231                         opts->dotsOK = 1;
1232                         break;
1233                 case Opt_nodots:
1234                         opts->dotsOK = 0;
1235                         break;
1236
1237                 /* vfat specific */
1238                 case Opt_charset:
1239                         if (opts->iocharset != fat_default_iocharset)
1240                                 kfree(opts->iocharset);
1241                         iocharset = match_strdup(&args[0]);
1242                         if (!iocharset)
1243                                 return -ENOMEM;
1244                         opts->iocharset = iocharset;
1245                         break;
1246                 case Opt_shortname_lower:
1247                         opts->shortname = VFAT_SFN_DISPLAY_LOWER
1248                                         | VFAT_SFN_CREATE_WIN95;
1249                         break;
1250                 case Opt_shortname_win95:
1251                         opts->shortname = VFAT_SFN_DISPLAY_WIN95
1252                                         | VFAT_SFN_CREATE_WIN95;
1253                         break;
1254                 case Opt_shortname_winnt:
1255                         opts->shortname = VFAT_SFN_DISPLAY_WINNT
1256                                         | VFAT_SFN_CREATE_WINNT;
1257                         break;
1258                 case Opt_shortname_mixed:
1259                         opts->shortname = VFAT_SFN_DISPLAY_WINNT
1260                                         | VFAT_SFN_CREATE_WIN95;
1261                         break;
1262                 case Opt_utf8_no:               /* 0 or no or false */
1263                         opts->utf8 = 0;
1264                         break;
1265                 case Opt_utf8_yes:              /* empty or 1 or yes or true */
1266                         opts->utf8 = 1;
1267                         break;
1268                 case Opt_uni_xl_no:             /* 0 or no or false */
1269                         opts->unicode_xlate = 0;
1270                         break;
1271                 case Opt_uni_xl_yes:            /* empty or 1 or yes or true */
1272                         opts->unicode_xlate = 1;
1273                         break;
1274                 case Opt_nonumtail_no:          /* 0 or no or false */
1275                         opts->numtail = 1;      /* negated option */
1276                         break;
1277                 case Opt_nonumtail_yes:         /* empty or 1 or yes or true */
1278                         opts->numtail = 0;      /* negated option */
1279                         break;
1280                 case Opt_rodir:
1281                         opts->rodir = 1;
1282                         break;
1283                 case Opt_discard:
1284                         opts->discard = 1;
1285                         break;
1286
1287                 /* obsolete mount options */
1288                 case Opt_obsolete:
1289                         fat_msg(sb, KERN_INFO, "\"%s\" option is obsolete, "
1290                                "not supported now", p);
1291                         break;
1292                 /* unknown option */
1293                 default:
1294                         if (!silent) {
1295                                 fat_msg(sb, KERN_ERR,
1296                                        "Unrecognized mount option \"%s\" "
1297                                        "or missing value", p);
1298                         }
1299                         return -EINVAL;
1300                 }
1301         }
1302
1303 out:
1304         /* UTF-8 doesn't provide FAT semantics */
1305         if (!strcmp(opts->iocharset, "utf8")) {
1306                 fat_msg(sb, KERN_WARNING, "utf8 is not a recommended IO charset"
1307                        " for FAT filesystems, filesystem will be "
1308                        "case sensitive!");
1309         }
1310
1311         /* If user doesn't specify allow_utime, it's initialized from dmask. */
1312         if (opts->allow_utime == (unsigned short)-1)
1313                 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1314         if (opts->unicode_xlate)
1315                 opts->utf8 = 0;
1316         if (opts->nfs == FAT_NFS_NOSTALE_RO) {
1317                 sb->s_flags |= MS_RDONLY;
1318                 sb->s_export_op = &fat_export_ops_nostale;
1319         }
1320
1321         return 0;
1322 }
1323
1324 static int fat_read_root(struct inode *inode)
1325 {
1326         struct super_block *sb = inode->i_sb;
1327         struct msdos_sb_info *sbi = MSDOS_SB(sb);
1328         int error;
1329
1330         MSDOS_I(inode)->i_pos = MSDOS_ROOT_INO;
1331         inode->i_uid = sbi->options.fs_uid;
1332         inode->i_gid = sbi->options.fs_gid;
1333         inode->i_version++;
1334         inode->i_generation = 0;
1335         inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
1336         inode->i_op = sbi->dir_ops;
1337         inode->i_fop = &fat_dir_operations;
1338         if (sbi->fat_bits == 32) {
1339                 MSDOS_I(inode)->i_start = sbi->root_cluster;
1340                 error = fat_calc_dir_size(inode);
1341                 if (error < 0)
1342                         return error;
1343         } else {
1344                 MSDOS_I(inode)->i_start = 0;
1345                 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1346         }
1347         inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1348                            & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1349         MSDOS_I(inode)->i_logstart = 0;
1350         MSDOS_I(inode)->mmu_private = inode->i_size;
1351         MSDOS_I(inode)->i_disksize = inode->i_size;
1352
1353         fat_save_attrs(inode, ATTR_DIR);
1354         inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1355         inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1356         set_nlink(inode, fat_subdirs(inode)+2);
1357
1358         return 0;
1359 }
1360
1361 static unsigned long calc_fat_clusters(struct super_block *sb)
1362 {
1363         struct msdos_sb_info *sbi = MSDOS_SB(sb);
1364
1365         /* Divide first to avoid overflow */
1366         if (sbi->fat_bits != 12) {
1367                 unsigned long ent_per_sec = sb->s_blocksize * 8 / sbi->fat_bits;
1368                 return ent_per_sec * sbi->fat_length;
1369         }
1370
1371         return sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1372 }
1373
1374 static bool fat_bpb_is_zero(struct fat_boot_sector *b)
1375 {
1376         if (get_unaligned_le16(&b->sector_size))
1377                 return false;
1378         if (b->sec_per_clus)
1379                 return false;
1380         if (b->reserved)
1381                 return false;
1382         if (b->fats)
1383                 return false;
1384         if (get_unaligned_le16(&b->dir_entries))
1385                 return false;
1386         if (get_unaligned_le16(&b->sectors))
1387                 return false;
1388         if (b->media)
1389                 return false;
1390         if (b->fat_length)
1391                 return false;
1392         if (b->secs_track)
1393                 return false;
1394         if (b->heads)
1395                 return false;
1396         return true;
1397 }
1398
1399 static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b,
1400         int silent, struct fat_bios_param_block *bpb)
1401 {
1402         int error = -EINVAL;
1403
1404         /* Read in BPB ... */
1405         memset(bpb, 0, sizeof(*bpb));
1406         bpb->fat_sector_size = get_unaligned_le16(&b->sector_size);
1407         bpb->fat_sec_per_clus = b->sec_per_clus;
1408         bpb->fat_reserved = le16_to_cpu(b->reserved);
1409         bpb->fat_fats = b->fats;
1410         bpb->fat_dir_entries = get_unaligned_le16(&b->dir_entries);
1411         bpb->fat_sectors = get_unaligned_le16(&b->sectors);
1412         bpb->fat_fat_length = le16_to_cpu(b->fat_length);
1413         bpb->fat_total_sect = le32_to_cpu(b->total_sect);
1414
1415         bpb->fat16_state = b->fat16.state;
1416         bpb->fat16_vol_id = get_unaligned_le32(b->fat16.vol_id);
1417
1418         bpb->fat32_length = le32_to_cpu(b->fat32.length);
1419         bpb->fat32_root_cluster = le32_to_cpu(b->fat32.root_cluster);
1420         bpb->fat32_info_sector = le16_to_cpu(b->fat32.info_sector);
1421         bpb->fat32_state = b->fat32.state;
1422         bpb->fat32_vol_id = get_unaligned_le32(b->fat32.vol_id);
1423
1424         /* Validate this looks like a FAT filesystem BPB */
1425         if (!bpb->fat_reserved) {
1426                 if (!silent)
1427                         fat_msg(sb, KERN_ERR,
1428                                 "bogus number of reserved sectors");
1429                 goto out;
1430         }
1431         if (!bpb->fat_fats) {
1432                 if (!silent)
1433                         fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
1434                 goto out;
1435         }
1436
1437         /*
1438          * Earlier we checked here that b->secs_track and b->head are nonzero,
1439          * but it turns out valid FAT filesystems can have zero there.
1440          */
1441
1442         if (!fat_valid_media(b->media)) {
1443                 if (!silent)
1444                         fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
1445                                 (unsigned)b->media);
1446                 goto out;
1447         }
1448
1449         if (!is_power_of_2(bpb->fat_sector_size)
1450             || (bpb->fat_sector_size < 512)
1451             || (bpb->fat_sector_size > 4096)) {
1452                 if (!silent)
1453                         fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
1454                                (unsigned)bpb->fat_sector_size);
1455                 goto out;
1456         }
1457
1458         if (!is_power_of_2(bpb->fat_sec_per_clus)) {
1459                 if (!silent)
1460                         fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
1461                                 (unsigned)bpb->fat_sec_per_clus);
1462                 goto out;
1463         }
1464
1465         error = 0;
1466
1467 out:
1468         return error;
1469 }
1470
1471 static int fat_read_static_bpb(struct super_block *sb,
1472         struct fat_boot_sector *b, int silent,
1473         struct fat_bios_param_block *bpb)
1474 {
1475         static const char *notdos1x = "This doesn't look like a DOS 1.x volume";
1476
1477         struct fat_floppy_defaults *fdefaults = NULL;
1478         int error = -EINVAL;
1479         sector_t bd_sects;
1480         unsigned i;
1481
1482         bd_sects = i_size_read(sb->s_bdev->bd_inode) / SECTOR_SIZE;
1483
1484         /* 16-bit DOS 1.x reliably wrote bootstrap short-jmp code */
1485         if (b->ignored[0] != 0xeb || b->ignored[2] != 0x90) {
1486                 if (!silent)
1487                         fat_msg(sb, KERN_ERR,
1488                                 "%s; no bootstrapping code", notdos1x);
1489                 goto out;
1490         }
1491
1492         /*
1493          * If any value in this region is non-zero, it isn't archaic
1494          * DOS.
1495          */
1496         if (!fat_bpb_is_zero(b)) {
1497                 if (!silent)
1498                         fat_msg(sb, KERN_ERR,
1499                                 "%s; DOS 2.x BPB is non-zero", notdos1x);
1500                 goto out;
1501         }
1502
1503         for (i = 0; i < ARRAY_SIZE(floppy_defaults); i++) {
1504                 if (floppy_defaults[i].nr_sectors == bd_sects) {
1505                         fdefaults = &floppy_defaults[i];
1506                         break;
1507                 }
1508         }
1509
1510         if (fdefaults == NULL) {
1511                 if (!silent)
1512                         fat_msg(sb, KERN_WARNING,
1513                                 "This looks like a DOS 1.x volume, but isn't a recognized floppy size (%llu sectors)",
1514                                 (u64)bd_sects);
1515                 goto out;
1516         }
1517
1518         if (!silent)
1519                 fat_msg(sb, KERN_INFO,
1520                         "This looks like a DOS 1.x volume; assuming default BPB values");
1521
1522         memset(bpb, 0, sizeof(*bpb));
1523         bpb->fat_sector_size = SECTOR_SIZE;
1524         bpb->fat_sec_per_clus = fdefaults->sec_per_clus;
1525         bpb->fat_reserved = 1;
1526         bpb->fat_fats = 2;
1527         bpb->fat_dir_entries = fdefaults->dir_entries;
1528         bpb->fat_sectors = fdefaults->nr_sectors;
1529         bpb->fat_fat_length = fdefaults->fat_length;
1530
1531         error = 0;
1532
1533 out:
1534         return error;
1535 }
1536
1537 /*
1538  * Read the super block of an MS-DOS FS.
1539  */
1540 int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
1541                    void (*setup)(struct super_block *))
1542 {
1543         struct inode *root_inode = NULL, *fat_inode = NULL;
1544         struct inode *fsinfo_inode = NULL;
1545         struct buffer_head *bh;
1546         struct fat_bios_param_block bpb;
1547         struct msdos_sb_info *sbi;
1548         u16 logical_sector_size;
1549         u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1550         int debug;
1551         long error;
1552         char buf[50];
1553
1554         /*
1555          * GFP_KERNEL is ok here, because while we do hold the
1556          * supeblock lock, memory pressure can't call back into
1557          * the filesystem, since we're only just about to mount
1558          * it and have no inodes etc active!
1559          */
1560         sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1561         if (!sbi)
1562                 return -ENOMEM;
1563         sb->s_fs_info = sbi;
1564
1565         sb->s_flags |= MS_NODIRATIME;
1566         sb->s_magic = MSDOS_SUPER_MAGIC;
1567         sb->s_op = &fat_sops;
1568         sb->s_export_op = &fat_export_ops;
1569         mutex_init(&sbi->nfs_build_inode_lock);
1570         ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
1571                              DEFAULT_RATELIMIT_BURST);
1572
1573         error = parse_options(sb, data, isvfat, silent, &debug, &sbi->options);
1574         if (error)
1575                 goto out_fail;
1576
1577         setup(sb); /* flavour-specific stuff that needs options */
1578
1579         error = -EIO;
1580         sb_min_blocksize(sb, 512);
1581         bh = sb_bread(sb, 0);
1582         if (bh == NULL) {
1583                 fat_msg(sb, KERN_ERR, "unable to read boot sector");
1584                 goto out_fail;
1585         }
1586
1587         error = fat_read_bpb(sb, (struct fat_boot_sector *)bh->b_data, silent,
1588                 &bpb);
1589         if (error == -EINVAL && sbi->options.dos1xfloppy)
1590                 error = fat_read_static_bpb(sb,
1591                         (struct fat_boot_sector *)bh->b_data, silent, &bpb);
1592         brelse(bh);
1593
1594         if (error == -EINVAL)
1595                 goto out_invalid;
1596         else if (error)
1597                 goto out_fail;
1598
1599         logical_sector_size = bpb.fat_sector_size;
1600         sbi->sec_per_clus = bpb.fat_sec_per_clus;
1601
1602         error = -EIO;
1603         if (logical_sector_size < sb->s_blocksize) {
1604                 fat_msg(sb, KERN_ERR, "logical sector size too small for device"
1605                        " (logical sector size = %u)", logical_sector_size);
1606                 goto out_fail;
1607         }
1608
1609         if (logical_sector_size > sb->s_blocksize) {
1610                 struct buffer_head *bh_resize;
1611
1612                 if (!sb_set_blocksize(sb, logical_sector_size)) {
1613                         fat_msg(sb, KERN_ERR, "unable to set blocksize %u",
1614                                logical_sector_size);
1615                         goto out_fail;
1616                 }
1617
1618                 /* Verify that the larger boot sector is fully readable */
1619                 bh_resize = sb_bread(sb, 0);
1620                 if (bh_resize == NULL) {
1621                         fat_msg(sb, KERN_ERR, "unable to read boot sector"
1622                                " (logical sector size = %lu)",
1623                                sb->s_blocksize);
1624                         goto out_fail;
1625                 }
1626                 brelse(bh_resize);
1627         }
1628
1629         mutex_init(&sbi->s_lock);
1630         sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1631         sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1632         sbi->fats = bpb.fat_fats;
1633         sbi->fat_bits = 0;              /* Don't know yet */
1634         sbi->fat_start = bpb.fat_reserved;
1635         sbi->fat_length = bpb.fat_fat_length;
1636         sbi->root_cluster = 0;
1637         sbi->free_clusters = -1;        /* Don't know yet */
1638         sbi->free_clus_valid = 0;
1639         sbi->prev_free = FAT_START_ENT;
1640         sb->s_maxbytes = 0xffffffff;
1641
1642         if (!sbi->fat_length && bpb.fat32_length) {
1643                 struct fat_boot_fsinfo *fsinfo;
1644                 struct buffer_head *fsinfo_bh;
1645
1646                 /* Must be FAT32 */
1647                 sbi->fat_bits = 32;
1648                 sbi->fat_length = bpb.fat32_length;
1649                 sbi->root_cluster = bpb.fat32_root_cluster;
1650
1651                 /* MC - if info_sector is 0, don't multiply by 0 */
1652                 sbi->fsinfo_sector = bpb.fat32_info_sector;
1653                 if (sbi->fsinfo_sector == 0)
1654                         sbi->fsinfo_sector = 1;
1655
1656                 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1657                 if (fsinfo_bh == NULL) {
1658                         fat_msg(sb, KERN_ERR, "bread failed, FSINFO block"
1659                                " (sector = %lu)", sbi->fsinfo_sector);
1660                         goto out_fail;
1661                 }
1662
1663                 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1664                 if (!IS_FSINFO(fsinfo)) {
1665                         fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: "
1666                                "0x%08x, 0x%08x (sector = %lu)",
1667                                le32_to_cpu(fsinfo->signature1),
1668                                le32_to_cpu(fsinfo->signature2),
1669                                sbi->fsinfo_sector);
1670                 } else {
1671                         if (sbi->options.usefree)
1672                                 sbi->free_clus_valid = 1;
1673                         sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1674                         sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1675                 }
1676
1677                 brelse(fsinfo_bh);
1678         }
1679
1680         /* interpret volume ID as a little endian 32 bit integer */
1681         if (sbi->fat_bits == 32)
1682                 sbi->vol_id = bpb.fat32_vol_id;
1683         else /* fat 16 or 12 */
1684                 sbi->vol_id = bpb.fat16_vol_id;
1685
1686         sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1687         sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1688
1689         sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1690         sbi->dir_entries = bpb.fat_dir_entries;
1691         if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1692                 if (!silent)
1693                         fat_msg(sb, KERN_ERR, "bogus directory-entries per block"
1694                                " (%u)", sbi->dir_entries);
1695                 goto out_invalid;
1696         }
1697
1698         rootdir_sectors = sbi->dir_entries
1699                 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1700         sbi->data_start = sbi->dir_start + rootdir_sectors;
1701         total_sectors = bpb.fat_sectors;
1702         if (total_sectors == 0)
1703                 total_sectors = bpb.fat_total_sect;
1704
1705         total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1706
1707         if (sbi->fat_bits != 32)
1708                 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1709
1710         /* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
1711         if (sbi->fat_bits == 32)
1712                 sbi->dirty = bpb.fat32_state & FAT_STATE_DIRTY;
1713         else /* fat 16 or 12 */
1714                 sbi->dirty = bpb.fat16_state & FAT_STATE_DIRTY;
1715
1716         /* check that FAT table does not overflow */
1717         fat_clusters = calc_fat_clusters(sb);
1718         total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1719         if (total_clusters > MAX_FAT(sb)) {
1720                 if (!silent)
1721                         fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
1722                                total_clusters);
1723                 goto out_invalid;
1724         }
1725
1726         sbi->max_cluster = total_clusters + FAT_START_ENT;
1727         /* check the free_clusters, it's not necessarily correct */
1728         if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1729                 sbi->free_clusters = -1;
1730         /* check the prev_free, it's not necessarily correct */
1731         sbi->prev_free %= sbi->max_cluster;
1732         if (sbi->prev_free < FAT_START_ENT)
1733                 sbi->prev_free = FAT_START_ENT;
1734
1735         /* set up enough so that it can read an inode */
1736         fat_hash_init(sb);
1737         dir_hash_init(sb);
1738         fat_ent_access_init(sb);
1739
1740         /*
1741          * The low byte of FAT's first entry must have same value with
1742          * media-field.  But in real world, too many devices is
1743          * writing wrong value.  So, removed that validity check.
1744          *
1745          * if (FAT_FIRST_ENT(sb, media) != first)
1746          */
1747
1748         error = -EINVAL;
1749         sprintf(buf, "cp%d", sbi->options.codepage);
1750         sbi->nls_disk = load_nls(buf);
1751         if (!sbi->nls_disk) {
1752                 fat_msg(sb, KERN_ERR, "codepage %s not found", buf);
1753                 goto out_fail;
1754         }
1755
1756         /* FIXME: utf8 is using iocharset for upper/lower conversion */
1757         if (sbi->options.isvfat) {
1758                 sbi->nls_io = load_nls(sbi->options.iocharset);
1759                 if (!sbi->nls_io) {
1760                         fat_msg(sb, KERN_ERR, "IO charset %s not found",
1761                                sbi->options.iocharset);
1762                         goto out_fail;
1763                 }
1764         }
1765
1766         error = -ENOMEM;
1767         fat_inode = new_inode(sb);
1768         if (!fat_inode)
1769                 goto out_fail;
1770         MSDOS_I(fat_inode)->i_pos = 0;
1771         sbi->fat_inode = fat_inode;
1772
1773         fsinfo_inode = new_inode(sb);
1774         if (!fsinfo_inode)
1775                 goto out_fail;
1776         fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
1777         sbi->fsinfo_inode = fsinfo_inode;
1778         insert_inode_hash(fsinfo_inode);
1779
1780         root_inode = new_inode(sb);
1781         if (!root_inode)
1782                 goto out_fail;
1783         root_inode->i_ino = MSDOS_ROOT_INO;
1784         root_inode->i_version = 1;
1785         error = fat_read_root(root_inode);
1786         if (error < 0) {
1787                 iput(root_inode);
1788                 goto out_fail;
1789         }
1790         error = -ENOMEM;
1791         insert_inode_hash(root_inode);
1792         fat_attach(root_inode, 0);
1793         sb->s_root = d_make_root(root_inode);
1794         if (!sb->s_root) {
1795                 fat_msg(sb, KERN_ERR, "get root inode failed");
1796                 goto out_fail;
1797         }
1798
1799         if (sbi->options.discard) {
1800                 struct request_queue *q = bdev_get_queue(sb->s_bdev);
1801                 if (!blk_queue_discard(q))
1802                         fat_msg(sb, KERN_WARNING,
1803                                         "mounting with \"discard\" option, but "
1804                                         "the device does not support discard");
1805         }
1806
1807         fat_set_state(sb, 1, 0);
1808         return 0;
1809
1810 out_invalid:
1811         error = -EINVAL;
1812         if (!silent)
1813                 fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem");
1814
1815 out_fail:
1816         if (fsinfo_inode)
1817                 iput(fsinfo_inode);
1818         if (fat_inode)
1819                 iput(fat_inode);
1820         unload_nls(sbi->nls_io);
1821         unload_nls(sbi->nls_disk);
1822         if (sbi->options.iocharset != fat_default_iocharset)
1823                 kfree(sbi->options.iocharset);
1824         sb->s_fs_info = NULL;
1825         kfree(sbi);
1826         return error;
1827 }
1828
1829 EXPORT_SYMBOL_GPL(fat_fill_super);
1830
1831 /*
1832  * helper function for fat_flush_inodes.  This writes both the inode
1833  * and the file data blocks, waiting for in flight data blocks before
1834  * the start of the call.  It does not wait for any io started
1835  * during the call
1836  */
1837 static int writeback_inode(struct inode *inode)
1838 {
1839
1840         int ret;
1841
1842         /* if we used wait=1, sync_inode_metadata waits for the io for the
1843         * inode to finish.  So wait=0 is sent down to sync_inode_metadata
1844         * and filemap_fdatawrite is used for the data blocks
1845         */
1846         ret = sync_inode_metadata(inode, 0);
1847         if (!ret)
1848                 ret = filemap_fdatawrite(inode->i_mapping);
1849         return ret;
1850 }
1851
1852 /*
1853  * write data and metadata corresponding to i1 and i2.  The io is
1854  * started but we do not wait for any of it to finish.
1855  *
1856  * filemap_flush is used for the block device, so if there is a dirty
1857  * page for a block already in flight, we will not wait and start the
1858  * io over again
1859  */
1860 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1861 {
1862         int ret = 0;
1863         if (!MSDOS_SB(sb)->options.flush)
1864                 return 0;
1865         if (i1)
1866                 ret = writeback_inode(i1);
1867         if (!ret && i2)
1868                 ret = writeback_inode(i2);
1869         if (!ret) {
1870                 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
1871                 ret = filemap_flush(mapping);
1872         }
1873         return ret;
1874 }
1875 EXPORT_SYMBOL_GPL(fat_flush_inodes);
1876
1877 static int __init init_fat_fs(void)
1878 {
1879         int err;
1880
1881         err = fat_cache_init();
1882         if (err)
1883                 return err;
1884
1885         err = fat_init_inodecache();
1886         if (err)
1887                 goto failed;
1888
1889         return 0;
1890
1891 failed:
1892         fat_cache_destroy();
1893         return err;
1894 }
1895
1896 static void __exit exit_fat_fs(void)
1897 {
1898         fat_cache_destroy();
1899         fat_destroy_inodecache();
1900 }
1901
1902 module_init(init_fat_fs)
1903 module_exit(exit_fat_fs)
1904
1905 MODULE_LICENSE("GPL");