fs/fat/inode.c

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