fs/fat/inode.c

   1 /*
   2  *  linux/fs/fat/inode.c
   3  *
   4  *  Written 1992,1993 by Werner Almesberger
   5  *  VFAT extensions by Gordon Chaffee, merged with msdos fs by Henrik Storner
   6  *  Rewritten for the constant inumbers support by Al Viro
   7  *
   8  *  Fixes:
   9  *
  10  *      Max Cohan: Fixed invalid FSINFO offset when info_sector is 0
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/time.h>
  16 #include <linux/slab.h>
  17 #include <linux/seq_file.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/mpage.h>
  20 #include <linux/buffer_head.h>
  21 #include <linux/exportfs.h>
  22 #include <linux/mount.h>
  23 #include <linux/vfs.h>
  24 #include <linux/parser.h>
  25 #include <linux/uio.h>
  26 #include <linux/writeback.h>
  27 #include <linux/log2.h>
  28 #include <linux/hash.h>
  29 #include <linux/blkdev.h>
  30 #include <asm/unaligned.h>
  31 #include "fat.h"
  32
  33 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET
  34 /* if user don't select VFAT, this is undefined. */
  35 #define CONFIG_FAT_DEFAULT_IOCHARSET    ""
  36 #endif
  37
  38 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
  39 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
  40
  41
  42 static int fat_add_cluster(struct inode *inode)
  43 {
  44         int err, cluster;
  45
  46         err = fat_alloc_clusters(inode, &cluster, 1);
  47         if (err)
  48                 return err;
  49         /* FIXME: this cluster should be added after data of this
  50          * cluster is writed */
  51         err = fat_chain_add(inode, cluster, 1);
  52         if (err)
  53                 fat_free_clusters(inode, cluster);
  54         return err;
  55 }
  56
  57 static inline int __fat_get_block(struct inode *inode, sector_t iblock,
  58                                   unsigned long *max_blocks,
  59                                   struct buffer_head *bh_result, int create)
  60 {
  61         struct super_block *sb = inode->i_sb;
  62         struct msdos_sb_info *sbi = MSDOS_SB(sb);
  63         unsigned long mapped_blocks;
  64         sector_t phys;
  65         int err, offset;
  66
  67         err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
  68         if (err)
  69                 return err;
  70         if (phys) {
  71                 map_bh(bh_result, sb, phys);
  72                 *max_blocks = min(mapped_blocks, *max_blocks);
  73                 return 0;
  74         }
  75         if (!create)
  76                 return 0;
  77
  78         if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
  79                 fat_fs_error(sb, "corrupted file size (i_pos %lld, %lld)",
  80                         MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
  81                 return -EIO;
  82         }
  83
  84         offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
  85         if (!offset) {
  86                 /* TODO: multiple cluster allocation would be desirable. */
  87                 err = fat_add_cluster(inode);
  88                 if (err)
  89                         return err;
  90         }
  91         /* available blocks on this cluster */
  92         mapped_blocks = sbi->sec_per_clus - offset;
  93
  94         *max_blocks = min(mapped_blocks, *max_blocks);
  95         MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
  96
  97         err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
  98         if (err)
  99                 return err;
 100
 101         BUG_ON(!phys);
 102         BUG_ON(*max_blocks != mapped_blocks);
 103         set_buffer_new(bh_result);
 104         map_bh(bh_result, sb, phys);
 105
 106         return 0;
 107 }
 108
 109 static int fat_get_block(struct inode *inode, sector_t iblock,
 110                          struct buffer_head *bh_result, int create)
 111 {
 112         struct super_block *sb = inode->i_sb;
 113         unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
 114         int err;
 115
 116         err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create);
 117         if (err)
 118                 return err;
 119         bh_result->b_size = max_blocks << sb->s_blocksize_bits;
 120         return 0;
 121 }
 122
 123 static int fat_writepage(struct page *page, struct writeback_control *wbc)
 124 {
 125         return block_write_full_page(page, fat_get_block, wbc);
 126 }
 127
 128 static int fat_writepages(struct address_space *mapping,
 129                           struct writeback_control *wbc)
 130 {
 131         return mpage_writepages(mapping, wbc, fat_get_block);
 132 }
 133
 134 static int fat_readpage(struct file *file, struct page *page)
 135 {
 136         return mpage_readpage(page, fat_get_block);
 137 }
 138
 139 static int fat_readpages(struct file *file, struct address_space *mapping,
 140                          struct list_head *pages, unsigned nr_pages)
 141 {
 142         return mpage_readpages(mapping, pages, nr_pages, fat_get_block);
 143 }
 144
 145 static void fat_write_failed(struct address_space *mapping, loff_t to)
 146 {
 147         struct inode *inode = mapping->host;
 148
 149         if (to > inode->i_size) {
 150                 truncate_pagecache(inode, to, inode->i_size);
 151                 fat_truncate_blocks(inode, inode->i_size);
 152         }
 153 }
 154
 155 static int fat_write_begin(struct file *file, struct address_space *mapping,
 156                         loff_t pos, unsigned len, unsigned flags,
 157                         struct page **pagep, void **fsdata)
 158 {
 159         int err;
 160
 161         *pagep = NULL;
 162         err = cont_write_begin(file, mapping, pos, len, flags,
 163                                 pagep, fsdata, fat_get_block,
 164                                 &MSDOS_I(mapping->host)->mmu_private);
 165         if (err < 0)
 166                 fat_write_failed(mapping, pos + len);
 167         return err;
 168 }
 169
 170 static int fat_write_end(struct file *file, struct address_space *mapping,
 171                         loff_t pos, unsigned len, unsigned copied,
 172                         struct page *pagep, void *fsdata)
 173 {
 174         struct inode *inode = mapping->host;
 175         int err;
 176         err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
 177         if (err < len)
 178                 fat_write_failed(mapping, pos + len);
 179         if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
 180                 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
 181                 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
 182                 mark_inode_dirty(inode);
 183         }
 184         return err;
 185 }
 186
 187 static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
 188                              const struct iovec *iov,
 189                              loff_t offset, unsigned long nr_segs)
 190 {
 191         struct file *file = iocb->ki_filp;
 192         struct address_space *mapping = file->f_mapping;
 193         struct inode *inode = mapping->host;
 194         ssize_t ret;
 195
 196         if (rw == WRITE) {
 197                 /*
 198                  * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
 199                  * so we need to update the ->mmu_private to block boundary.
 200                  *
 201                  * But we must fill the remaining area or hole by nul for
 202                  * updating ->mmu_private.
 203                  *
 204                  * Return 0, and fallback to normal buffered write.
 205                  */
 206                 loff_t size = offset + iov_length(iov, nr_segs);
 207                 if (MSDOS_I(inode)->mmu_private < size)
 208                         return 0;
 209         }
 210
 211         /*
 212          * FAT need to use the DIO_LOCKING for avoiding the race
 213          * condition of fat_get_block() and ->truncate().
 214          */
 215         ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
 216                                  fat_get_block);
 217         if (ret < 0 && (rw & WRITE))
 218                 fat_write_failed(mapping, offset + iov_length(iov, nr_segs));
 219
 220         return ret;
 221 }
 222
 223 static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
 224 {
 225         sector_t blocknr;
 226
 227         /* fat_get_cluster() assumes the requested blocknr isn't truncated. */
 228         down_read(&MSDOS_I(mapping->host)->truncate_lock);
 229         blocknr = generic_block_bmap(mapping, block, fat_get_block);
 230         up_read(&MSDOS_I(mapping->host)->truncate_lock);
 231
 232         return blocknr;
 233 }
 234
 235 static const struct address_space_operations fat_aops = {
 236         .readpage       = fat_readpage,
 237         .readpages      = fat_readpages,
 238         .writepage      = fat_writepage,
 239         .writepages     = fat_writepages,
 240         .write_begin    = fat_write_begin,
 241         .write_end      = fat_write_end,
 242         .direct_IO      = fat_direct_IO,
 243         .bmap           = _fat_bmap
 244 };
 245
 246 /*
 247  * New FAT inode stuff. We do the following:
 248  *      a) i_ino is constant and has nothing with on-disk location.
 249  *      b) FAT manages its own cache of directory entries.
 250  *      c) *This* cache is indexed by on-disk location.
 251  *      d) inode has an associated directory entry, all right, but
 252  *              it may be unhashed.
 253  *      e) currently entries are stored within struct inode. That should
 254  *              change.
 255  *      f) we deal with races in the following way:
 256  *              1. readdir() and lookup() do FAT-dir-cache lookup.
 257  *              2. rename() unhashes the F-d-c entry and rehashes it in
 258  *                      a new place.
 259  *              3. unlink() and rmdir() unhash F-d-c entry.
 260  *              4. fat_write_inode() checks whether the thing is unhashed.
 261  *                      If it is we silently return. If it isn't we do bread(),
 262  *                      check if the location is still valid and retry if it
 263  *                      isn't. Otherwise we do changes.
 264  *              5. Spinlock is used to protect hash/unhash/location check/lookup
 265  *              6. fat_evict_inode() unhashes the F-d-c entry.
 266  *              7. lookup() and readdir() do igrab() if they find a F-d-c entry
 267  *                      and consider negative result as cache miss.
 268  */
 269
 270 static void fat_hash_init(struct super_block *sb)
 271 {
 272         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 273         int i;
 274
 275         spin_lock_init(&sbi->inode_hash_lock);
 276         for (i = 0; i < FAT_HASH_SIZE; i++)
 277                 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
 278 }
 279
 280 static inline unsigned long fat_hash(loff_t i_pos)
 281 {
 282         return hash_32(i_pos, FAT_HASH_BITS);
 283 }
 284
 285 static void dir_hash_init(struct super_block *sb)
 286 {
 287         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 288         int i;
 289
 290         spin_lock_init(&sbi->dir_hash_lock);
 291         for (i = 0; i < FAT_HASH_SIZE; i++)
 292                 INIT_HLIST_HEAD(&sbi->dir_hashtable[i]);
 293 }
 294
 295 void fat_attach(struct inode *inode, loff_t i_pos)
 296 {
 297         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
 298
 299         if (inode->i_ino != MSDOS_ROOT_INO) {
 300                 struct hlist_head *head =   sbi->inode_hashtable
 301                                           + fat_hash(i_pos);
 302
 303                 spin_lock(&sbi->inode_hash_lock);
 304                 MSDOS_I(inode)->i_pos = i_pos;
 305                 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
 306                 spin_unlock(&sbi->inode_hash_lock);
 307         }
 308
 309         /* If NFS support is enabled, cache the mapping of start cluster
 310          * to directory inode. This is used during reconnection of
 311          * dentries to the filesystem root.
 312          */
 313         if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
 314                 struct hlist_head *d_head = sbi->dir_hashtable;
 315                 d_head += fat_dir_hash(MSDOS_I(inode)->i_logstart);
 316
 317                 spin_lock(&sbi->dir_hash_lock);
 318                 hlist_add_head(&MSDOS_I(inode)->i_dir_hash, d_head);
 319                 spin_unlock(&sbi->dir_hash_lock);
 320         }
 321 }
 322 EXPORT_SYMBOL_GPL(fat_attach);
 323
 324 void fat_detach(struct inode *inode)
 325 {
 326         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
 327         spin_lock(&sbi->inode_hash_lock);
 328         MSDOS_I(inode)->i_pos = 0;
 329         hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
 330         spin_unlock(&sbi->inode_hash_lock);
 331
 332         if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
 333                 spin_lock(&sbi->dir_hash_lock);
 334                 hlist_del_init(&MSDOS_I(inode)->i_dir_hash);
 335                 spin_unlock(&sbi->dir_hash_lock);
 336         }
 337 }
 338 EXPORT_SYMBOL_GPL(fat_detach);
 339
 340 struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
 341 {
 342         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 343         struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
 344         struct msdos_inode_info *i;
 345         struct inode *inode = NULL;
 346
 347         spin_lock(&sbi->inode_hash_lock);
 348         hlist_for_each_entry(i, head, i_fat_hash) {
 349                 BUG_ON(i->vfs_inode.i_sb != sb);
 350                 if (i->i_pos != i_pos)
 351                         continue;
 352                 inode = igrab(&i->vfs_inode);
 353                 if (inode)
 354                         break;
 355         }
 356         spin_unlock(&sbi->inode_hash_lock);
 357         return inode;
 358 }
 359
 360 static int is_exec(unsigned char *extension)
 361 {
 362         unsigned char *exe_extensions = "EXECOMBAT", *walk;
 363
 364         for (walk = exe_extensions; *walk; walk += 3)
 365                 if (!strncmp(extension, walk, 3))
 366                         return 1;
 367         return 0;
 368 }
 369
 370 static int fat_calc_dir_size(struct inode *inode)
 371 {
 372         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
 373         int ret, fclus, dclus;
 374
 375         inode->i_size = 0;
 376         if (MSDOS_I(inode)->i_start == 0)
 377                 return 0;
 378
 379         ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
 380         if (ret < 0)
 381                 return ret;
 382         inode->i_size = (fclus + 1) << sbi->cluster_bits;
 383
 384         return 0;
 385 }
 386
 387 /* doesn't deal with root inode */
 388 static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
 389 {
 390         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
 391         int error;
 392
 393         MSDOS_I(inode)->i_pos = 0;
 394         inode->i_uid = sbi->options.fs_uid;
 395         inode->i_gid = sbi->options.fs_gid;
 396         inode->i_version++;
 397         inode->i_generation = get_seconds();
 398
 399         if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
 400                 inode->i_generation &= ~1;
 401                 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
 402                 inode->i_op = sbi->dir_ops;
 403                 inode->i_fop = &fat_dir_operations;
 404
 405                 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
 406                 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
 407                 error = fat_calc_dir_size(inode);
 408                 if (error < 0)
 409                         return error;
 410                 MSDOS_I(inode)->mmu_private = inode->i_size;
 411
 412                 set_nlink(inode, fat_subdirs(inode));
 413         } else { /* not a directory */
 414                 inode->i_generation |= 1;
 415                 inode->i_mode = fat_make_mode(sbi, de->attr,
 416                         ((sbi->options.showexec && !is_exec(de->name + 8))
 417                          ? S_IRUGO|S_IWUGO : S_IRWXUGO));
 418                 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
 419
 420                 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
 421                 inode->i_size = le32_to_cpu(de->size);
 422                 inode->i_op = &fat_file_inode_operations;
 423                 inode->i_fop = &fat_file_operations;
 424                 inode->i_mapping->a_ops = &fat_aops;
 425                 MSDOS_I(inode)->mmu_private = inode->i_size;
 426         }
 427         if (de->attr & ATTR_SYS) {
 428                 if (sbi->options.sys_immutable)
 429                         inode->i_flags |= S_IMMUTABLE;
 430         }
 431         fat_save_attrs(inode, de->attr);
 432
 433         inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
 434                            & ~((loff_t)sbi->cluster_size - 1)) >> 9;
 435
 436         fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0);
 437         if (sbi->options.isvfat) {
 438                 fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime,
 439                                   de->cdate, de->ctime_cs);
 440                 fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
 441         } else
 442                 inode->i_ctime = inode->i_atime = inode->i_mtime;
 443
 444         return 0;
 445 }
 446
 447 struct inode *fat_build_inode(struct super_block *sb,
 448                         struct msdos_dir_entry *de, loff_t i_pos)
 449 {
 450         struct inode *inode;
 451         int err;
 452
 453         inode = fat_iget(sb, i_pos);
 454         if (inode)
 455                 goto out;
 456         inode = new_inode(sb);
 457         if (!inode) {
 458                 inode = ERR_PTR(-ENOMEM);
 459                 goto out;
 460         }
 461         inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
 462         inode->i_version = 1;
 463         err = fat_fill_inode(inode, de);
 464         if (err) {
 465                 iput(inode);
 466                 inode = ERR_PTR(err);
 467                 goto out;
 468         }
 469         fat_attach(inode, i_pos);
 470         insert_inode_hash(inode);
 471 out:
 472         return inode;
 473 }
 474
 475 EXPORT_SYMBOL_GPL(fat_build_inode);
 476
 477 static void fat_evict_inode(struct inode *inode)
 478 {
 479         truncate_inode_pages(&inode->i_data, 0);
 480         if (!inode->i_nlink) {
 481                 inode->i_size = 0;
 482                 fat_truncate_blocks(inode, 0);
 483         }
 484         invalidate_inode_buffers(inode);
 485         clear_inode(inode);
 486         fat_cache_inval_inode(inode);
 487         fat_detach(inode);
 488 }
 489
 490 static void fat_set_state(struct super_block *sb,
 491                         unsigned int set, unsigned int force)
 492 {
 493         struct buffer_head *bh;
 494         struct fat_boot_sector *b;
 495         struct msdos_sb_info *sbi = sb->s_fs_info;
 496
 497         /* do not change any thing if mounted read only */
 498         if ((sb->s_flags & MS_RDONLY) && !force)
 499                 return;
 500
 501         /* do not change state if fs was dirty */
 502         if (sbi->dirty) {
 503                 /* warn only on set (mount). */
 504                 if (set)
 505                         fat_msg(sb, KERN_WARNING, "Volume was not properly "
 506                                 "unmounted. Some data may be corrupt. "
 507                                 "Please run fsck.");
 508                 return;
 509         }
 510
 511         bh = sb_bread(sb, 0);
 512         if (bh == NULL) {
 513                 fat_msg(sb, KERN_ERR, "unable to read boot sector "
 514                         "to mark fs as dirty");
 515                 return;
 516         }
 517
 518         b = (struct fat_boot_sector *) bh->b_data;
 519
 520         if (sbi->fat_bits == 32) {
 521                 if (set)
 522                         b->fat32.state |= FAT_STATE_DIRTY;
 523                 else
 524                         b->fat32.state &= ~FAT_STATE_DIRTY;
 525         } else /* fat 16 and 12 */ {
 526                 if (set)
 527                         b->fat16.state |= FAT_STATE_DIRTY;
 528                 else
 529                         b->fat16.state &= ~FAT_STATE_DIRTY;
 530         }
 531
 532         mark_buffer_dirty(bh);
 533         sync_dirty_buffer(bh);
 534         brelse(bh);
 535 }
 536
 537 static void fat_put_super(struct super_block *sb)
 538 {
 539         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 540
 541         fat_set_state(sb, 0, 0);
 542
 543         iput(sbi->fsinfo_inode);
 544         iput(sbi->fat_inode);
 545
 546         unload_nls(sbi->nls_disk);
 547         unload_nls(sbi->nls_io);
 548
 549         if (sbi->options.iocharset != fat_default_iocharset)
 550                 kfree(sbi->options.iocharset);
 551
 552         sb->s_fs_info = NULL;
 553         kfree(sbi);
 554 }
 555
 556 static struct kmem_cache *fat_inode_cachep;
 557
 558 static struct inode *fat_alloc_inode(struct super_block *sb)
 559 {
 560         struct msdos_inode_info *ei;
 561         ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
 562         if (!ei)
 563                 return NULL;
 564
 565         init_rwsem(&ei->truncate_lock);
 566         return &ei->vfs_inode;
 567 }
 568
 569 static void fat_i_callback(struct rcu_head *head)
 570 {
 571         struct inode *inode = container_of(head, struct inode, i_rcu);
 572         kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
 573 }
 574
 575 static void fat_destroy_inode(struct inode *inode)
 576 {
 577         call_rcu(&inode->i_rcu, fat_i_callback);
 578 }
 579
 580 static void init_once(void *foo)
 581 {
 582         struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
 583
 584         spin_lock_init(&ei->cache_lru_lock);
 585         ei->nr_caches = 0;
 586         ei->cache_valid_id = FAT_CACHE_VALID + 1;
 587         INIT_LIST_HEAD(&ei->cache_lru);
 588         INIT_HLIST_NODE(&ei->i_fat_hash);
 589         INIT_HLIST_NODE(&ei->i_dir_hash);
 590         inode_init_once(&ei->vfs_inode);
 591 }
 592
 593 static int __init fat_init_inodecache(void)
 594 {
 595         fat_inode_cachep = kmem_cache_create("fat_inode_cache",
 596                                              sizeof(struct msdos_inode_info),
 597                                              0, (SLAB_RECLAIM_ACCOUNT|
 598                                                 SLAB_MEM_SPREAD),
 599                                              init_once);
 600         if (fat_inode_cachep == NULL)
 601                 return -ENOMEM;
 602         return 0;
 603 }
 604
 605 static void __exit fat_destroy_inodecache(void)
 606 {
 607         /*
 608          * Make sure all delayed rcu free inodes are flushed before we
 609          * destroy cache.
 610          */
 611         rcu_barrier();
 612         kmem_cache_destroy(fat_inode_cachep);
 613 }
 614
 615 static int fat_remount(struct super_block *sb, int *flags, char *data)
 616 {
 617         int new_rdonly;
 618         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 619         *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME);
 620
 621         /* make sure we update state on remount. */
 622         new_rdonly = *flags & MS_RDONLY;
 623         if (new_rdonly != (sb->s_flags & MS_RDONLY)) {
 624                 if (new_rdonly)
 625                         fat_set_state(sb, 0, 0);
 626                 else
 627                         fat_set_state(sb, 1, 1);
 628         }
 629         return 0;
 630 }
 631
 632 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
 633 {
 634         struct super_block *sb = dentry->d_sb;
 635         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 636         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 637
 638         /* If the count of free cluster is still unknown, counts it here. */
 639         if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
 640                 int err = fat_count_free_clusters(dentry->d_sb);
 641                 if (err)
 642                         return err;
 643         }
 644
 645         buf->f_type = dentry->d_sb->s_magic;
 646         buf->f_bsize = sbi->cluster_size;
 647         buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
 648         buf->f_bfree = sbi->free_clusters;
 649         buf->f_bavail = sbi->free_clusters;
 650         buf->f_fsid.val[0] = (u32)id;
 651         buf->f_fsid.val[1] = (u32)(id >> 32);
 652         buf->f_namelen =
 653                 (sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE;
 654
 655         return 0;
 656 }
 657
 658 static int __fat_write_inode(struct inode *inode, int wait)
 659 {
 660         struct super_block *sb = inode->i_sb;
 661         struct msdos_sb_info *sbi = MSDOS_SB(sb);
 662         struct buffer_head *bh;
 663         struct msdos_dir_entry *raw_entry;
 664         loff_t i_pos;
 665         int err;
 666
 667         if (inode->i_ino == MSDOS_ROOT_INO)
 668                 return 0;
 669
 670 retry:
 671         i_pos = fat_i_pos_read(sbi, inode);
 672         if (!i_pos)
 673                 return 0;
 674
 675         bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits);
 676         if (!bh) {
 677                 fat_msg(sb, KERN_ERR, "unable to read inode block "
 678                        "for updating (i_pos %lld)", i_pos);
 679                 return -EIO;
 680         }
 681         spin_lock(&sbi->inode_hash_lock);
 682         if (i_pos != MSDOS_I(inode)->i_pos) {
 683                 spin_unlock(&sbi->inode_hash_lock);
 684                 brelse(bh);
 685                 goto retry;
 686         }
 687
 688         raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
 689             [i_pos & (sbi->dir_per_block - 1)];
 690         if (S_ISDIR(inode->i_mode))
 691                 raw_entry->size = 0;
 692         else
 693                 raw_entry->size = cpu_to_le32(inode->i_size);
 694         raw_entry->attr = fat_make_attrs(inode);
 695         fat_set_start(raw_entry, MSDOS_I(inode)->i_logstart);
 696         fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
 697                           &raw_entry->date, NULL);
 698         if (sbi->options.isvfat) {
 699                 __le16 atime;
 700                 fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime,
 701                                   &raw_entry->cdate, &raw_entry->ctime_cs);
 702                 fat_time_unix2fat(sbi, &inode->i_atime, &atime,
 703                                   &raw_entry->adate, NULL);
 704         }
 705         spin_unlock(&sbi->inode_hash_lock);
 706         mark_buffer_dirty(bh);
 707         err = 0;
 708         if (wait)
 709                 err = sync_dirty_buffer(bh);
 710         brelse(bh);
 711         return err;
 712 }
 713
 714 static int fat_write_inode(struct inode *inode, struct writeback_control *wbc)
 715 {
 716         int err;
 717
 718         if (inode->i_ino == MSDOS_FSINFO_INO) {
 719                 struct super_block *sb = inode->i_sb;
 720
 721                 mutex_lock(&MSDOS_SB(sb)->s_lock);
 722                 err = fat_clusters_flush(sb);
 723                 mutex_unlock(&MSDOS_SB(sb)->s_lock);
 724         } else
 725                 err = __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
 726
 727         return err;
 728 }
 729
 730 int fat_sync_inode(struct inode *inode)
 731 {
 732         return __fat_write_inode(inode, 1);
 733 }
 734
 735 EXPORT_SYMBOL_GPL(fat_sync_inode);
 736
 737 static int fat_show_options(struct seq_file *m, struct dentry *root);
 738 static const struct super_operations fat_sops = {
 739         .alloc_inode    = fat_alloc_inode,
 740         .destroy_inode  = fat_destroy_inode,
 741         .write_inode    = fat_write_inode,
 742         .evict_inode    = fat_evict_inode,
 743         .put_super      = fat_put_super,
 744         .statfs         = fat_statfs,
 745         .remount_fs     = fat_remount,
 746
 747         .show_options   = fat_show_options,
 748 };
 749
 750 static const struct export_operations fat_export_ops = {
 751         .fh_to_dentry   = fat_fh_to_dentry,
 752         .fh_to_parent   = fat_fh_to_parent,
 753         .get_parent     = fat_get_parent,
 754 };
 755
 756 static int fat_show_options(struct seq_file *m, struct dentry *root)
 757 {
 758         struct msdos_sb_info *sbi = MSDOS_SB(root->d_sb);
 759         struct fat_mount_options *opts = &sbi->options;
 760         int isvfat = opts->isvfat;
 761
 762         if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
 763                 seq_printf(m, ",uid=%u",
 764                                 from_kuid_munged(&init_user_ns, opts->fs_uid));
 765         if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
 766                 seq_printf(m, ",gid=%u",
 767                                 from_kgid_munged(&init_user_ns, opts->fs_gid));
 768         seq_printf(m, ",fmask=%04o", opts->fs_fmask);
 769         seq_printf(m, ",dmask=%04o", opts->fs_dmask);
 770         if (opts->allow_utime)
 771                 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
 772         if (sbi->nls_disk)
 773                 /* strip "cp" prefix from displayed option */
 774                 seq_printf(m, ",codepage=%s", &sbi->nls_disk->charset[2]);
 775         if (isvfat) {
 776                 if (sbi->nls_io)
 777                         seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
 778
 779                 switch (opts->shortname) {
 780                 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
 781                         seq_puts(m, ",shortname=win95");
 782                         break;
 783                 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
 784                         seq_puts(m, ",shortname=winnt");
 785                         break;
 786                 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
 787                         seq_puts(m, ",shortname=mixed");
 788                         break;
 789                 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
 790                         seq_puts(m, ",shortname=lower");
 791                         break;
 792                 default:
 793                         seq_puts(m, ",shortname=unknown");
 794                         break;
 795                 }
 796         }
 797         if (opts->name_check != 'n')
 798                 seq_printf(m, ",check=%c", opts->name_check);
 799         if (opts->usefree)
 800                 seq_puts(m, ",usefree");
 801         if (opts->quiet)
 802                 seq_puts(m, ",quiet");
 803         if (opts->showexec)
 804                 seq_puts(m, ",showexec");
 805         if (opts->sys_immutable)
 806                 seq_puts(m, ",sys_immutable");
 807         if (!isvfat) {
 808                 if (opts->dotsOK)
 809                         seq_puts(m, ",dotsOK=yes");
 810                 if (opts->nocase)
 811                         seq_puts(m, ",nocase");
 812         } else {
 813                 if (opts->utf8)
 814                         seq_puts(m, ",utf8");
 815                 if (opts->unicode_xlate)
 816                         seq_puts(m, ",uni_xlate");
 817                 if (!opts->numtail)
 818                         seq_puts(m, ",nonumtail");
 819                 if (opts->rodir)
 820                         seq_puts(m, ",rodir");
 821         }
 822         if (opts->flush)
 823                 seq_puts(m, ",flush");
 824         if (opts->tz_set) {
 825                 if (opts->time_offset)
 826                         seq_printf(m, ",time_offset=%d", opts->time_offset);
 827                 else
 828                         seq_puts(m, ",tz=UTC");
 829         }
 830         if (opts->errors == FAT_ERRORS_CONT)
 831                 seq_puts(m, ",errors=continue");
 832         else if (opts->errors == FAT_ERRORS_PANIC)
 833                 seq_puts(m, ",errors=panic");
 834         else
 835                 seq_puts(m, ",errors=remount-ro");
 836         if (opts->nfs == FAT_NFS_NOSTALE_RO)
 837                 seq_puts(m, ",nfs=nostale_ro");
 838         else if (opts->nfs)
 839                 seq_puts(m, ",nfs=stale_rw");
 840         if (opts->discard)
 841                 seq_puts(m, ",discard");
 842
 843         return 0;
 844 }
 845
 846 enum {
 847         Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
 848         Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
 849         Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
 850         Opt_immutable, Opt_dots, Opt_nodots,
 851         Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
 852         Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
 853         Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
 854         Opt_obsolete, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
 855         Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_time_offset,
 856         Opt_nfs_stale_rw, Opt_nfs_nostale_ro, Opt_err,
 857 };
 858
 859 static const match_table_t fat_tokens = {
 860         {Opt_check_r, "check=relaxed"},
 861         {Opt_check_s, "check=strict"},
 862         {Opt_check_n, "check=normal"},
 863         {Opt_check_r, "check=r"},
 864         {Opt_check_s, "check=s"},
 865         {Opt_check_n, "check=n"},
 866         {Opt_uid, "uid=%u"},
 867         {Opt_gid, "gid=%u"},
 868         {Opt_umask, "umask=%o"},
 869         {Opt_dmask, "dmask=%o"},
 870         {Opt_fmask, "fmask=%o"},
 871         {Opt_allow_utime, "allow_utime=%o"},
 872         {Opt_codepage, "codepage=%u"},
 873         {Opt_usefree, "usefree"},
 874         {Opt_nocase, "nocase"},
 875         {Opt_quiet, "quiet"},
 876         {Opt_showexec, "showexec"},
 877         {Opt_debug, "debug"},
 878         {Opt_immutable, "sys_immutable"},
 879         {Opt_flush, "flush"},
 880         {Opt_tz_utc, "tz=UTC"},
 881         {Opt_time_offset, "time_offset=%d"},
 882         {Opt_err_cont, "errors=continue"},
 883         {Opt_err_panic, "errors=panic"},
 884         {Opt_err_ro, "errors=remount-ro"},
 885         {Opt_discard, "discard"},
 886         {Opt_nfs_stale_rw, "nfs"},
 887         {Opt_nfs_stale_rw, "nfs=stale_rw"},
 888         {Opt_nfs_nostale_ro, "nfs=nostale_ro"},
 889         {Opt_obsolete, "conv=binary"},
 890         {Opt_obsolete, "conv=text"},
 891         {Opt_obsolete, "conv=auto"},
 892         {Opt_obsolete, "conv=b"},
 893         {Opt_obsolete, "conv=t"},
 894         {Opt_obsolete, "conv=a"},
 895         {Opt_obsolete, "fat=%u"},
 896         {Opt_obsolete, "blocksize=%u"},
 897         {Opt_obsolete, "cvf_format=%20s"},
 898         {Opt_obsolete, "cvf_options=%100s"},
 899         {Opt_obsolete, "posix"},
 900         {Opt_err, NULL},
 901 };
 902 static const match_table_t msdos_tokens = {
 903         {Opt_nodots, "nodots"},
 904         {Opt_nodots, "dotsOK=no"},
 905         {Opt_dots, "dots"},
 906         {Opt_dots, "dotsOK=yes"},
 907         {Opt_err, NULL}
 908 };
 909 static const match_table_t vfat_tokens = {
 910         {Opt_charset, "iocharset=%s"},
 911         {Opt_shortname_lower, "shortname=lower"},
 912         {Opt_shortname_win95, "shortname=win95"},
 913         {Opt_shortname_winnt, "shortname=winnt"},
 914         {Opt_shortname_mixed, "shortname=mixed"},
 915         {Opt_utf8_no, "utf8=0"},                /* 0 or no or false */
 916         {Opt_utf8_no, "utf8=no"},
 917         {Opt_utf8_no, "utf8=false"},
 918         {Opt_utf8_yes, "utf8=1"},               /* empty or 1 or yes or true */
 919         {Opt_utf8_yes, "utf8=yes"},
 920         {Opt_utf8_yes, "utf8=true"},
 921         {Opt_utf8_yes, "utf8"},
 922         {Opt_uni_xl_no, "uni_xlate=0"},         /* 0 or no or false */
 923         {Opt_uni_xl_no, "uni_xlate=no"},
 924         {Opt_uni_xl_no, "uni_xlate=false"},
 925         {Opt_uni_xl_yes, "uni_xlate=1"},        /* empty or 1 or yes or true */
 926         {Opt_uni_xl_yes, "uni_xlate=yes"},
 927         {Opt_uni_xl_yes, "uni_xlate=true"},
 928         {Opt_uni_xl_yes, "uni_xlate"},
 929         {Opt_nonumtail_no, "nonumtail=0"},      /* 0 or no or false */
 930         {Opt_nonumtail_no, "nonumtail=no"},
 931         {Opt_nonumtail_no, "nonumtail=false"},
 932         {Opt_nonumtail_yes, "nonumtail=1"},     /* empty or 1 or yes or true */
 933         {Opt_nonumtail_yes, "nonumtail=yes"},
 934         {Opt_nonumtail_yes, "nonumtail=true"},
 935         {Opt_nonumtail_yes, "nonumtail"},
 936         {Opt_rodir, "rodir"},
 937         {Opt_err, NULL}
 938 };
 939
 940 static int parse_options(struct super_block *sb, char *options, int is_vfat,
 941                          int silent, int *debug, struct fat_mount_options *opts)
 942 {
 943         char *p;
 944         substring_t args[MAX_OPT_ARGS];
 945         int option;
 946         char *iocharset;
 947
 948         opts->isvfat = is_vfat;
 949
 950         opts->fs_uid = current_uid();
 951         opts->fs_gid = current_gid();
 952         opts->fs_fmask = opts->fs_dmask = current_umask();
 953         opts->allow_utime = -1;
 954         opts->codepage = fat_default_codepage;
 955         opts->iocharset = fat_default_iocharset;
 956         if (is_vfat) {
 957                 opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95;
 958                 opts->rodir = 0;
 959         } else {
 960                 opts->shortname = 0;
 961                 opts->rodir = 1;
 962         }
 963         opts->name_check = 'n';
 964         opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK =  0;
 965         opts->utf8 = opts->unicode_xlate = 0;
 966         opts->numtail = 1;
 967         opts->usefree = opts->nocase = 0;
 968         opts->tz_set = 0;
 969         opts->nfs = 0;
 970         opts->errors = FAT_ERRORS_RO;
 971         *debug = 0;
 972
 973         if (!options)
 974                 goto out;
 975
 976         while ((p = strsep(&options, ",")) != NULL) {
 977                 int token;
 978                 if (!*p)
 979                         continue;
 980
 981                 token = match_token(p, fat_tokens, args);
 982                 if (token == Opt_err) {
 983                         if (is_vfat)
 984                                 token = match_token(p, vfat_tokens, args);
 985                         else
 986                                 token = match_token(p, msdos_tokens, args);
 987                 }
 988                 switch (token) {
 989                 case Opt_check_s:
 990                         opts->name_check = 's';
 991                         break;
 992                 case Opt_check_r:
 993                         opts->name_check = 'r';
 994                         break;
 995                 case Opt_check_n:
 996                         opts->name_check = 'n';
 997                         break;
 998                 case Opt_usefree:
 999                         opts->usefree = 1;
1000                         break;
1001                 case Opt_nocase:
1002                         if (!is_vfat)
1003                                 opts->nocase = 1;
1004                         else {
1005                                 /* for backward compatibility */
1006                                 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1007                                         | VFAT_SFN_CREATE_WIN95;
1008                         }
1009                         break;
1010                 case Opt_quiet:
1011                         opts->quiet = 1;
1012                         break;
1013                 case Opt_showexec:
1014                         opts->showexec = 1;
1015                         break;
1016                 case Opt_debug:
1017                         *debug = 1;
1018                         break;
1019                 case Opt_immutable:
1020                         opts->sys_immutable = 1;
1021                         break;
1022                 case Opt_uid:
1023                         if (match_int(&args[0], &option))
1024                                 return -EINVAL;
1025                         opts->fs_uid = make_kuid(current_user_ns(), option);
1026                         if (!uid_valid(opts->fs_uid))
1027                                 return -EINVAL;
1028                         break;
1029                 case Opt_gid:
1030                         if (match_int(&args[0], &option))
1031                                 return -EINVAL;
1032                         opts->fs_gid = make_kgid(current_user_ns(), option);
1033                         if (!gid_valid(opts->fs_gid))
1034                                 return -EINVAL;
1035                         break;
1036                 case Opt_umask:
1037                         if (match_octal(&args[0], &option))
1038                                 return -EINVAL;
1039                         opts->fs_fmask = opts->fs_dmask = option;
1040                         break;
1041                 case Opt_dmask:
1042                         if (match_octal(&args[0], &option))
1043                                 return -EINVAL;
1044                         opts->fs_dmask = option;
1045                         break;
1046                 case Opt_fmask:
1047                         if (match_octal(&args[0], &option))
1048                                 return -EINVAL;
1049                         opts->fs_fmask = option;
1050                         break;
1051                 case Opt_allow_utime:
1052                         if (match_octal(&args[0], &option))
1053                                 return -EINVAL;
1054                         opts->allow_utime = option & (S_IWGRP | S_IWOTH);
1055                         break;
1056                 case Opt_codepage:
1057                         if (match_int(&args[0], &option))
1058                                 return -EINVAL;
1059                         opts->codepage = option;
1060                         break;
1061                 case Opt_flush:
1062                         opts->flush = 1;
1063                         break;
1064                 case Opt_time_offset:
1065                         if (match_int(&args[0], &option))
1066                                 return -EINVAL;
1067                         if (option < -12 * 60 || option > 12 * 60)
1068                                 return -EINVAL;
1069                         opts->tz_set = 1;
1070                         opts->time_offset = option;
1071                         break;
1072                 case Opt_tz_utc:
1073                         opts->tz_set = 1;
1074                         opts->time_offset = 0;
1075                         break;
1076                 case Opt_err_cont:
1077                         opts->errors = FAT_ERRORS_CONT;
1078                         break;
1079                 case Opt_err_panic:
1080                         opts->errors = FAT_ERRORS_PANIC;
1081                         break;
1082                 case Opt_err_ro:
1083                         opts->errors = FAT_ERRORS_RO;
1084                         break;
1085                 case Opt_nfs_stale_rw:
1086                         opts->nfs = FAT_NFS_STALE_RW;
1087                         break;
1088                 case Opt_nfs_nostale_ro:
1089                         opts->nfs = FAT_NFS_NOSTALE_RO;
1090                         break;
1091
1092                 /* msdos specific */
1093                 case Opt_dots:
1094                         opts->dotsOK = 1;
1095                         break;
1096                 case Opt_nodots:
1097                         opts->dotsOK = 0;
1098                         break;
1099
1100                 /* vfat specific */
1101                 case Opt_charset:
1102                         if (opts->iocharset != fat_default_iocharset)
1103                                 kfree(opts->iocharset);
1104                         iocharset = match_strdup(&args[0]);
1105                         if (!iocharset)
1106                                 return -ENOMEM;
1107                         opts->iocharset = iocharset;
1108                         break;
1109                 case Opt_shortname_lower:
1110                         opts->shortname = VFAT_SFN_DISPLAY_LOWER
1111                                         | VFAT_SFN_CREATE_WIN95;
1112                         break;
1113                 case Opt_shortname_win95:
1114                         opts->shortname = VFAT_SFN_DISPLAY_WIN95
1115                                         | VFAT_SFN_CREATE_WIN95;
1116                         break;
1117                 case Opt_shortname_winnt:
1118                         opts->shortname = VFAT_SFN_DISPLAY_WINNT
1119                                         | VFAT_SFN_CREATE_WINNT;
1120                         break;
1121                 case Opt_shortname_mixed:
1122                         opts->shortname = VFAT_SFN_DISPLAY_WINNT
1123                                         | VFAT_SFN_CREATE_WIN95;
1124                         break;
1125                 case Opt_utf8_no:               /* 0 or no or false */
1126                         opts->utf8 = 0;
1127                         break;
1128                 case Opt_utf8_yes:              /* empty or 1 or yes or true */
1129                         opts->utf8 = 1;
1130                         break;
1131                 case Opt_uni_xl_no:             /* 0 or no or false */
1132                         opts->unicode_xlate = 0;
1133                         break;
1134                 case Opt_uni_xl_yes:            /* empty or 1 or yes or true */
1135                         opts->unicode_xlate = 1;
1136                         break;
1137                 case Opt_nonumtail_no:          /* 0 or no or false */
1138                         opts->numtail = 1;      /* negated option */
1139                         break;
1140                 case Opt_nonumtail_yes:         /* empty or 1 or yes or true */
1141                         opts->numtail = 0;      /* negated option */
1142                         break;
1143                 case Opt_rodir:
1144                         opts->rodir = 1;
1145                         break;
1146                 case Opt_discard:
1147                         opts->discard = 1;
1148                         break;
1149
1150                 /* obsolete mount options */
1151                 case Opt_obsolete:
1152                         fat_msg(sb, KERN_INFO, "\"%s\" option is obsolete, "
1153                                "not supported now", p);
1154                         break;
1155                 /* unknown option */
1156                 default:
1157                         if (!silent) {
1158                                 fat_msg(sb, KERN_ERR,
1159                                        "Unrecognized mount option \"%s\" "
1160                                        "or missing value", p);
1161                         }
1162                         return -EINVAL;
1163                 }
1164         }
1165
1166 out:
1167         /* UTF-8 doesn't provide FAT semantics */
1168         if (!strcmp(opts->iocharset, "utf8")) {
1169                 fat_msg(sb, KERN_WARNING, "utf8 is not a recommended IO charset"
1170                        " for FAT filesystems, filesystem will be "
1171                        "case sensitive!");
1172         }
1173
1174         /* If user doesn't specify allow_utime, it's initialized from dmask. */
1175         if (opts->allow_utime == (unsigned short)-1)
1176                 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1177         if (opts->unicode_xlate)
1178                 opts->utf8 = 0;
1179         if (opts->nfs == FAT_NFS_NOSTALE_RO)
1180                 sb->s_flags |= MS_RDONLY;
1181
1182         return 0;
1183 }
1184
1185 static int fat_read_root(struct inode *inode)
1186 {
1187         struct super_block *sb = inode->i_sb;
1188         struct msdos_sb_info *sbi = MSDOS_SB(sb);
1189         int error;
1190
1191         MSDOS_I(inode)->i_pos = 0;
1192         inode->i_uid = sbi->options.fs_uid;
1193         inode->i_gid = sbi->options.fs_gid;
1194         inode->i_version++;
1195         inode->i_generation = 0;
1196         inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
1197         inode->i_op = sbi->dir_ops;
1198         inode->i_fop = &fat_dir_operations;
1199         if (sbi->fat_bits == 32) {
1200                 MSDOS_I(inode)->i_start = sbi->root_cluster;
1201                 error = fat_calc_dir_size(inode);
1202                 if (error < 0)
1203                         return error;
1204         } else {
1205                 MSDOS_I(inode)->i_start = 0;
1206                 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1207         }
1208         inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1209                            & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1210         MSDOS_I(inode)->i_logstart = 0;
1211         MSDOS_I(inode)->mmu_private = inode->i_size;
1212
1213         fat_save_attrs(inode, ATTR_DIR);
1214         inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1215         inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1216         set_nlink(inode, fat_subdirs(inode)+2);
1217
1218         return 0;
1219 }
1220
1221 /*
1222  * Read the super block of an MS-DOS FS.
1223  */
1224 int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
1225                    void (*setup)(struct super_block *))
1226 {
1227         struct inode *root_inode = NULL, *fat_inode = NULL;
1228         struct inode *fsinfo_inode = NULL;
1229         struct buffer_head *bh;
1230         struct fat_boot_sector *b;
1231         struct msdos_sb_info *sbi;
1232         u16 logical_sector_size;
1233         u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1234         int debug;
1235         unsigned int media;
1236         long error;
1237         char buf[50];
1238
1239         /*
1240          * GFP_KERNEL is ok here, because while we do hold the
1241          * supeblock lock, memory pressure can't call back into
1242          * the filesystem, since we're only just about to mount
1243          * it and have no inodes etc active!
1244          */
1245         sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1246         if (!sbi)
1247                 return -ENOMEM;
1248         sb->s_fs_info = sbi;
1249
1250         sb->s_flags |= MS_NODIRATIME;
1251         sb->s_magic = MSDOS_SUPER_MAGIC;
1252         sb->s_op = &fat_sops;
1253         sb->s_export_op = &fat_export_ops;
1254         ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
1255                              DEFAULT_RATELIMIT_BURST);
1256
1257         error = parse_options(sb, data, isvfat, silent, &debug, &sbi->options);
1258         if (error)
1259                 goto out_fail;
1260
1261         setup(sb); /* flavour-specific stuff that needs options */
1262
1263         error = -EIO;
1264         sb_min_blocksize(sb, 512);
1265         bh = sb_bread(sb, 0);
1266         if (bh == NULL) {
1267                 fat_msg(sb, KERN_ERR, "unable to read boot sector");
1268                 goto out_fail;
1269         }
1270
1271         b = (struct fat_boot_sector *) bh->b_data;
1272         if (!b->reserved) {
1273                 if (!silent)
1274                         fat_msg(sb, KERN_ERR, "bogus number of reserved sectors");
1275                 brelse(bh);
1276                 goto out_invalid;
1277         }
1278         if (!b->fats) {
1279                 if (!silent)
1280                         fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
1281                 brelse(bh);
1282                 goto out_invalid;
1283         }
1284
1285         /*
1286          * Earlier we checked here that b->secs_track and b->head are nonzero,
1287          * but it turns out valid FAT filesystems can have zero there.
1288          */
1289
1290         media = b->media;
1291         if (!fat_valid_media(media)) {
1292                 if (!silent)
1293                         fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
1294                                media);
1295                 brelse(bh);
1296                 goto out_invalid;
1297         }
1298         logical_sector_size = get_unaligned_le16(&b->sector_size);
1299         if (!is_power_of_2(logical_sector_size)
1300             || (logical_sector_size < 512)
1301             || (logical_sector_size > 4096)) {
1302                 if (!silent)
1303                         fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
1304                                logical_sector_size);
1305                 brelse(bh);
1306                 goto out_invalid;
1307         }
1308         sbi->sec_per_clus = b->sec_per_clus;
1309         if (!is_power_of_2(sbi->sec_per_clus)) {
1310                 if (!silent)
1311                         fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
1312                                sbi->sec_per_clus);
1313                 brelse(bh);
1314                 goto out_invalid;
1315         }
1316
1317         if (logical_sector_size < sb->s_blocksize) {
1318                 fat_msg(sb, KERN_ERR, "logical sector size too small for device"
1319                        " (logical sector size = %u)", logical_sector_size);
1320                 brelse(bh);
1321                 goto out_fail;
1322         }
1323         if (logical_sector_size > sb->s_blocksize) {
1324                 brelse(bh);
1325
1326                 if (!sb_set_blocksize(sb, logical_sector_size)) {
1327                         fat_msg(sb, KERN_ERR, "unable to set blocksize %u",
1328                                logical_sector_size);
1329                         goto out_fail;
1330                 }
1331                 bh = sb_bread(sb, 0);
1332                 if (bh == NULL) {
1333                         fat_msg(sb, KERN_ERR, "unable to read boot sector"
1334                                " (logical sector size = %lu)",
1335                                sb->s_blocksize);
1336                         goto out_fail;
1337                 }
1338                 b = (struct fat_boot_sector *) bh->b_data;
1339         }
1340
1341         mutex_init(&sbi->s_lock);
1342         sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1343         sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1344         sbi->fats = b->fats;
1345         sbi->fat_bits = 0;              /* Don't know yet */
1346         sbi->fat_start = le16_to_cpu(b->reserved);
1347         sbi->fat_length = le16_to_cpu(b->fat_length);
1348         sbi->root_cluster = 0;
1349         sbi->free_clusters = -1;        /* Don't know yet */
1350         sbi->free_clus_valid = 0;
1351         sbi->prev_free = FAT_START_ENT;
1352         sb->s_maxbytes = 0xffffffff;
1353
1354         if (!sbi->fat_length && b->fat32.length) {
1355                 struct fat_boot_fsinfo *fsinfo;
1356                 struct buffer_head *fsinfo_bh;
1357
1358                 /* Must be FAT32 */
1359                 sbi->fat_bits = 32;
1360                 sbi->fat_length = le32_to_cpu(b->fat32.length);
1361                 sbi->root_cluster = le32_to_cpu(b->fat32.root_cluster);
1362
1363                 /* MC - if info_sector is 0, don't multiply by 0 */
1364                 sbi->fsinfo_sector = le16_to_cpu(b->fat32.info_sector);
1365                 if (sbi->fsinfo_sector == 0)
1366                         sbi->fsinfo_sector = 1;
1367
1368                 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1369                 if (fsinfo_bh == NULL) {
1370                         fat_msg(sb, KERN_ERR, "bread failed, FSINFO block"
1371                                " (sector = %lu)", sbi->fsinfo_sector);
1372                         brelse(bh);
1373                         goto out_fail;
1374                 }
1375
1376                 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1377                 if (!IS_FSINFO(fsinfo)) {
1378                         fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: "
1379                                "0x%08x, 0x%08x (sector = %lu)",
1380                                le32_to_cpu(fsinfo->signature1),
1381                                le32_to_cpu(fsinfo->signature2),
1382                                sbi->fsinfo_sector);
1383                 } else {
1384                         if (sbi->options.usefree)
1385                                 sbi->free_clus_valid = 1;
1386                         sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1387                         sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1388                 }
1389
1390                 brelse(fsinfo_bh);
1391         }
1392
1393         sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1394         sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1395
1396         sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1397         sbi->dir_entries = get_unaligned_le16(&b->dir_entries);
1398         if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1399                 if (!silent)
1400                         fat_msg(sb, KERN_ERR, "bogus directory-entries per block"
1401                                " (%u)", sbi->dir_entries);
1402                 brelse(bh);
1403                 goto out_invalid;
1404         }
1405
1406         rootdir_sectors = sbi->dir_entries
1407                 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1408         sbi->data_start = sbi->dir_start + rootdir_sectors;
1409         total_sectors = get_unaligned_le16(&b->sectors);
1410         if (total_sectors == 0)
1411                 total_sectors = le32_to_cpu(b->total_sect);
1412
1413         total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1414
1415         if (sbi->fat_bits != 32)
1416                 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1417
1418         /* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
1419         if (sbi->fat_bits == 32)
1420                 sbi->dirty = b->fat32.state & FAT_STATE_DIRTY;
1421         else /* fat 16 or 12 */
1422                 sbi->dirty = b->fat16.state & FAT_STATE_DIRTY;
1423
1424         /* check that FAT table does not overflow */
1425         fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1426         total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1427         if (total_clusters > MAX_FAT(sb)) {
1428                 if (!silent)
1429                         fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
1430                                total_clusters);
1431                 brelse(bh);
1432                 goto out_invalid;
1433         }
1434
1435         sbi->max_cluster = total_clusters + FAT_START_ENT;
1436         /* check the free_clusters, it's not necessarily correct */
1437         if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1438                 sbi->free_clusters = -1;
1439         /* check the prev_free, it's not necessarily correct */
1440         sbi->prev_free %= sbi->max_cluster;
1441         if (sbi->prev_free < FAT_START_ENT)
1442                 sbi->prev_free = FAT_START_ENT;
1443
1444         brelse(bh);
1445
1446         /* set up enough so that it can read an inode */
1447         fat_hash_init(sb);
1448         dir_hash_init(sb);
1449         fat_ent_access_init(sb);
1450
1451         /*
1452          * The low byte of FAT's first entry must have same value with
1453          * media-field.  But in real world, too many devices is
1454          * writing wrong value.  So, removed that validity check.
1455          *
1456          * if (FAT_FIRST_ENT(sb, media) != first)
1457          */
1458
1459         error = -EINVAL;
1460         sprintf(buf, "cp%d", sbi->options.codepage);
1461         sbi->nls_disk = load_nls(buf);
1462         if (!sbi->nls_disk) {
1463                 fat_msg(sb, KERN_ERR, "codepage %s not found", buf);
1464                 goto out_fail;
1465         }
1466
1467         /* FIXME: utf8 is using iocharset for upper/lower conversion */
1468         if (sbi->options.isvfat) {
1469                 sbi->nls_io = load_nls(sbi->options.iocharset);
1470                 if (!sbi->nls_io) {
1471                         fat_msg(sb, KERN_ERR, "IO charset %s not found",
1472                                sbi->options.iocharset);
1473                         goto out_fail;
1474                 }
1475         }
1476
1477         error = -ENOMEM;
1478         fat_inode = new_inode(sb);
1479         if (!fat_inode)
1480                 goto out_fail;
1481         MSDOS_I(fat_inode)->i_pos = 0;
1482         sbi->fat_inode = fat_inode;
1483
1484         fsinfo_inode = new_inode(sb);
1485         if (!fsinfo_inode)
1486                 goto out_fail;
1487         fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
1488         sbi->fsinfo_inode = fsinfo_inode;
1489         insert_inode_hash(fsinfo_inode);
1490
1491         root_inode = new_inode(sb);
1492         if (!root_inode)
1493                 goto out_fail;
1494         root_inode->i_ino = MSDOS_ROOT_INO;
1495         root_inode->i_version = 1;
1496         error = fat_read_root(root_inode);
1497         if (error < 0) {
1498                 iput(root_inode);
1499                 goto out_fail;
1500         }
1501         error = -ENOMEM;
1502         insert_inode_hash(root_inode);
1503         fat_attach(root_inode, 0);
1504         sb->s_root = d_make_root(root_inode);
1505         if (!sb->s_root) {
1506                 fat_msg(sb, KERN_ERR, "get root inode failed");
1507                 goto out_fail;
1508         }
1509
1510         if (sbi->options.discard) {
1511                 struct request_queue *q = bdev_get_queue(sb->s_bdev);
1512                 if (!blk_queue_discard(q))
1513                         fat_msg(sb, KERN_WARNING,
1514                                         "mounting with \"discard\" option, but "
1515                                         "the device does not support discard");
1516         }
1517
1518         fat_set_state(sb, 1, 0);
1519         return 0;
1520
1521 out_invalid:
1522         error = -EINVAL;
1523         if (!silent)
1524                 fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem");
1525
1526 out_fail:
1527         if (fsinfo_inode)
1528                 iput(fsinfo_inode);
1529         if (fat_inode)
1530                 iput(fat_inode);
1531         unload_nls(sbi->nls_io);
1532         unload_nls(sbi->nls_disk);
1533         if (sbi->options.iocharset != fat_default_iocharset)
1534                 kfree(sbi->options.iocharset);
1535         sb->s_fs_info = NULL;
1536         kfree(sbi);
1537         return error;
1538 }
1539
1540 EXPORT_SYMBOL_GPL(fat_fill_super);
1541
1542 /*
1543  * helper function for fat_flush_inodes.  This writes both the inode
1544  * and the file data blocks, waiting for in flight data blocks before
1545  * the start of the call.  It does not wait for any io started
1546  * during the call
1547  */
1548 static int writeback_inode(struct inode *inode)
1549 {
1550
1551         int ret;
1552
1553         /* if we used wait=1, sync_inode_metadata waits for the io for the
1554         * inode to finish.  So wait=0 is sent down to sync_inode_metadata
1555         * and filemap_fdatawrite is used for the data blocks
1556         */
1557         ret = sync_inode_metadata(inode, 0);
1558         if (!ret)
1559                 ret = filemap_fdatawrite(inode->i_mapping);
1560         return ret;
1561 }
1562
1563 /*
1564  * write data and metadata corresponding to i1 and i2.  The io is
1565  * started but we do not wait for any of it to finish.
1566  *
1567  * filemap_flush is used for the block device, so if there is a dirty
1568  * page for a block already in flight, we will not wait and start the
1569  * io over again
1570  */
1571 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1572 {
1573         int ret = 0;
1574         if (!MSDOS_SB(sb)->options.flush)
1575                 return 0;
1576         if (i1)
1577                 ret = writeback_inode(i1);
1578         if (!ret && i2)
1579                 ret = writeback_inode(i2);
1580         if (!ret) {
1581                 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
1582                 ret = filemap_flush(mapping);
1583         }
1584         return ret;
1585 }
1586 EXPORT_SYMBOL_GPL(fat_flush_inodes);
1587
1588 static int __init init_fat_fs(void)
1589 {
1590         int err;
1591
1592         err = fat_cache_init();
1593         if (err)
1594                 return err;
1595
1596         err = fat_init_inodecache();
1597         if (err)
1598                 goto failed;
1599
1600         return 0;
1601
1602 failed:
1603         fat_cache_destroy();
1604         return err;
1605 }
1606
1607 static void __exit exit_fat_fs(void)
1608 {
1609         fat_cache_destroy();
1610         fat_destroy_inodecache();
1611 }
1612
1613 module_init(init_fat_fs)
1614 module_exit(exit_fat_fs)
1615
1616 MODULE_LICENSE("GPL");