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