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