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/smp_lock.h> 18 #include <linux/seq_file.h> 19 #include <linux/msdos_fs.h> 20 #include <linux/pagemap.h> 21 #include <linux/buffer_head.h> 22 #include <linux/mount.h> 23 #include <linux/vfs.h> 24 #include <linux/parser.h> 25 #include <asm/unaligned.h> 26 27 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET 28 /* if user don't select VFAT, this is undefined. */ 29 #define CONFIG_FAT_DEFAULT_IOCHARSET "" 30 #endif 31 32 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE; 33 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET; 34 35 36 static int fat_add_cluster(struct inode *inode) 37 { 38 int err, cluster; 39 40 err = fat_alloc_clusters(inode, &cluster, 1); 41 if (err) 42 return err; 43 /* FIXME: this cluster should be added after data of this 44 * cluster is writed */ 45 err = fat_chain_add(inode, cluster, 1); 46 if (err) 47 fat_free_clusters(inode, cluster); 48 return err; 49 } 50 51 static int fat_get_block(struct inode *inode, sector_t iblock, 52 struct buffer_head *bh_result, int create) 53 { 54 struct super_block *sb = inode->i_sb; 55 sector_t phys; 56 int err; 57 58 err = fat_bmap(inode, iblock, &phys); 59 if (err) 60 return err; 61 if (phys) { 62 map_bh(bh_result, sb, phys); 63 return 0; 64 } 65 if (!create) 66 return 0; 67 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) { 68 fat_fs_panic(sb, "corrupted file size (i_pos %lld, %lld)", 69 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private); 70 return -EIO; 71 } 72 if (!((unsigned long)iblock & (MSDOS_SB(sb)->sec_per_clus - 1))) { 73 err = fat_add_cluster(inode); 74 if (err) 75 return err; 76 } 77 MSDOS_I(inode)->mmu_private += sb->s_blocksize; 78 err = fat_bmap(inode, iblock, &phys); 79 if (err) 80 return err; 81 if (!phys) 82 BUG(); 83 set_buffer_new(bh_result); 84 map_bh(bh_result, sb, phys); 85 return 0; 86 } 87 88 static int fat_writepage(struct page *page, struct writeback_control *wbc) 89 { 90 return block_write_full_page(page, fat_get_block, wbc); 91 } 92 93 static int fat_readpage(struct file *file, struct page *page) 94 { 95 return block_read_full_page(page, fat_get_block); 96 } 97 98 static int fat_prepare_write(struct file *file, struct page *page, 99 unsigned from, unsigned to) 100 { 101 return cont_prepare_write(page, from, to, fat_get_block, 102 &MSDOS_I(page->mapping->host)->mmu_private); 103 } 104 105 static int fat_commit_write(struct file *file, struct page *page, 106 unsigned from, unsigned to) 107 { 108 struct inode *inode = page->mapping->host; 109 int err = generic_commit_write(file, page, from, to); 110 if (!err && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) { 111 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC; 112 MSDOS_I(inode)->i_attrs |= ATTR_ARCH; 113 mark_inode_dirty(inode); 114 } 115 return err; 116 } 117 118 static sector_t _fat_bmap(struct address_space *mapping, sector_t block) 119 { 120 return generic_block_bmap(mapping, block, fat_get_block); 121 } 122 123 static struct address_space_operations fat_aops = { 124 .readpage = fat_readpage, 125 .writepage = fat_writepage, 126 .sync_page = block_sync_page, 127 .prepare_write = fat_prepare_write, 128 .commit_write = fat_commit_write, 129 .bmap = _fat_bmap 130 }; 131 132 /* 133 * New FAT inode stuff. We do the following: 134 * a) i_ino is constant and has nothing with on-disk location. 135 * b) FAT manages its own cache of directory entries. 136 * c) *This* cache is indexed by on-disk location. 137 * d) inode has an associated directory entry, all right, but 138 * it may be unhashed. 139 * e) currently entries are stored within struct inode. That should 140 * change. 141 * f) we deal with races in the following way: 142 * 1. readdir() and lookup() do FAT-dir-cache lookup. 143 * 2. rename() unhashes the F-d-c entry and rehashes it in 144 * a new place. 145 * 3. unlink() and rmdir() unhash F-d-c entry. 146 * 4. fat_write_inode() checks whether the thing is unhashed. 147 * If it is we silently return. If it isn't we do bread(), 148 * check if the location is still valid and retry if it 149 * isn't. Otherwise we do changes. 150 * 5. Spinlock is used to protect hash/unhash/location check/lookup 151 * 6. fat_clear_inode() unhashes the F-d-c entry. 152 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry 153 * and consider negative result as cache miss. 154 */ 155 156 static void fat_hash_init(struct super_block *sb) 157 { 158 struct msdos_sb_info *sbi = MSDOS_SB(sb); 159 int i; 160 161 spin_lock_init(&sbi->inode_hash_lock); 162 for (i = 0; i < FAT_HASH_SIZE; i++) 163 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]); 164 } 165 166 static inline unsigned long fat_hash(struct super_block *sb, loff_t i_pos) 167 { 168 unsigned long tmp = (unsigned long)i_pos | (unsigned long) sb; 169 tmp = tmp + (tmp >> FAT_HASH_BITS) + (tmp >> FAT_HASH_BITS * 2); 170 return tmp & FAT_HASH_MASK; 171 } 172 173 void fat_attach(struct inode *inode, loff_t i_pos) 174 { 175 struct super_block *sb = inode->i_sb; 176 struct msdos_sb_info *sbi = MSDOS_SB(sb); 177 178 spin_lock(&sbi->inode_hash_lock); 179 MSDOS_I(inode)->i_pos = i_pos; 180 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, 181 sbi->inode_hashtable + fat_hash(sb, i_pos)); 182 spin_unlock(&sbi->inode_hash_lock); 183 } 184 185 EXPORT_SYMBOL(fat_attach); 186 187 void fat_detach(struct inode *inode) 188 { 189 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 190 spin_lock(&sbi->inode_hash_lock); 191 MSDOS_I(inode)->i_pos = 0; 192 hlist_del_init(&MSDOS_I(inode)->i_fat_hash); 193 spin_unlock(&sbi->inode_hash_lock); 194 } 195 196 EXPORT_SYMBOL(fat_detach); 197 198 struct inode *fat_iget(struct super_block *sb, loff_t i_pos) 199 { 200 struct msdos_sb_info *sbi = MSDOS_SB(sb); 201 struct hlist_head *head = sbi->inode_hashtable + fat_hash(sb, i_pos); 202 struct hlist_node *_p; 203 struct msdos_inode_info *i; 204 struct inode *inode = NULL; 205 206 spin_lock(&sbi->inode_hash_lock); 207 hlist_for_each_entry(i, _p, head, i_fat_hash) { 208 BUG_ON(i->vfs_inode.i_sb != sb); 209 if (i->i_pos != i_pos) 210 continue; 211 inode = igrab(&i->vfs_inode); 212 if (inode) 213 break; 214 } 215 spin_unlock(&sbi->inode_hash_lock); 216 return inode; 217 } 218 219 static int is_exec(unsigned char *extension) 220 { 221 unsigned char *exe_extensions = "EXECOMBAT", *walk; 222 223 for (walk = exe_extensions; *walk; walk += 3) 224 if (!strncmp(extension, walk, 3)) 225 return 1; 226 return 0; 227 } 228 229 static int fat_calc_dir_size(struct inode *inode) 230 { 231 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 232 int ret, fclus, dclus; 233 234 inode->i_size = 0; 235 if (MSDOS_I(inode)->i_start == 0) 236 return 0; 237 238 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); 239 if (ret < 0) 240 return ret; 241 inode->i_size = (fclus + 1) << sbi->cluster_bits; 242 243 return 0; 244 } 245 246 /* doesn't deal with root inode */ 247 static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de) 248 { 249 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 250 int error; 251 252 MSDOS_I(inode)->i_pos = 0; 253 inode->i_uid = sbi->options.fs_uid; 254 inode->i_gid = sbi->options.fs_gid; 255 inode->i_version++; 256 inode->i_generation = get_seconds(); 257 258 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) { 259 inode->i_generation &= ~1; 260 inode->i_mode = MSDOS_MKMODE(de->attr, 261 S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR; 262 inode->i_op = sbi->dir_ops; 263 inode->i_fop = &fat_dir_operations; 264 265 MSDOS_I(inode)->i_start = le16_to_cpu(de->start); 266 if (sbi->fat_bits == 32) 267 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16); 268 269 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 270 error = fat_calc_dir_size(inode); 271 if (error < 0) 272 return error; 273 MSDOS_I(inode)->mmu_private = inode->i_size; 274 275 inode->i_nlink = fat_subdirs(inode); 276 } else { /* not a directory */ 277 inode->i_generation |= 1; 278 inode->i_mode = MSDOS_MKMODE(de->attr, 279 ((sbi->options.showexec && 280 !is_exec(de->ext)) 281 ? S_IRUGO|S_IWUGO : S_IRWXUGO) 282 & ~sbi->options.fs_fmask) | S_IFREG; 283 MSDOS_I(inode)->i_start = le16_to_cpu(de->start); 284 if (sbi->fat_bits == 32) 285 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16); 286 287 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 288 inode->i_size = le32_to_cpu(de->size); 289 inode->i_op = &fat_file_inode_operations; 290 inode->i_fop = &fat_file_operations; 291 inode->i_mapping->a_ops = &fat_aops; 292 MSDOS_I(inode)->mmu_private = inode->i_size; 293 } 294 if (de->attr & ATTR_SYS) { 295 if (sbi->options.sys_immutable) 296 inode->i_flags |= S_IMMUTABLE; 297 } 298 MSDOS_I(inode)->i_attrs = de->attr & ATTR_UNUSED; 299 /* this is as close to the truth as we can get ... */ 300 inode->i_blksize = sbi->cluster_size; 301 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 302 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 303 inode->i_mtime.tv_sec = 304 date_dos2unix(le16_to_cpu(de->time), le16_to_cpu(de->date)); 305 inode->i_mtime.tv_nsec = 0; 306 if (sbi->options.isvfat) { 307 int secs = de->ctime_cs / 100; 308 int csecs = de->ctime_cs % 100; 309 inode->i_ctime.tv_sec = 310 date_dos2unix(le16_to_cpu(de->ctime), 311 le16_to_cpu(de->cdate)) + secs; 312 inode->i_ctime.tv_nsec = csecs * 10000000; 313 inode->i_atime.tv_sec = 314 date_dos2unix(le16_to_cpu(0), le16_to_cpu(de->adate)); 315 inode->i_atime.tv_nsec = 0; 316 } else 317 inode->i_ctime = inode->i_atime = inode->i_mtime; 318 319 return 0; 320 } 321 322 struct inode *fat_build_inode(struct super_block *sb, 323 struct msdos_dir_entry *de, loff_t i_pos) 324 { 325 struct inode *inode; 326 int err; 327 328 inode = fat_iget(sb, i_pos); 329 if (inode) 330 goto out; 331 inode = new_inode(sb); 332 if (!inode) { 333 inode = ERR_PTR(-ENOMEM); 334 goto out; 335 } 336 inode->i_ino = iunique(sb, MSDOS_ROOT_INO); 337 inode->i_version = 1; 338 err = fat_fill_inode(inode, de); 339 if (err) { 340 iput(inode); 341 inode = ERR_PTR(err); 342 goto out; 343 } 344 fat_attach(inode, i_pos); 345 insert_inode_hash(inode); 346 out: 347 return inode; 348 } 349 350 EXPORT_SYMBOL(fat_build_inode); 351 352 static void fat_delete_inode(struct inode *inode) 353 { 354 truncate_inode_pages(&inode->i_data, 0); 355 356 if (!is_bad_inode(inode)) { 357 inode->i_size = 0; 358 fat_truncate(inode); 359 } 360 clear_inode(inode); 361 } 362 363 static void fat_clear_inode(struct inode *inode) 364 { 365 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 366 367 if (is_bad_inode(inode)) 368 return; 369 lock_kernel(); 370 spin_lock(&sbi->inode_hash_lock); 371 fat_cache_inval_inode(inode); 372 hlist_del_init(&MSDOS_I(inode)->i_fat_hash); 373 spin_unlock(&sbi->inode_hash_lock); 374 unlock_kernel(); 375 } 376 377 static void fat_put_super(struct super_block *sb) 378 { 379 struct msdos_sb_info *sbi = MSDOS_SB(sb); 380 381 if (!(sb->s_flags & MS_RDONLY)) 382 fat_clusters_flush(sb); 383 384 if (sbi->nls_disk) { 385 unload_nls(sbi->nls_disk); 386 sbi->nls_disk = NULL; 387 sbi->options.codepage = fat_default_codepage; 388 } 389 if (sbi->nls_io) { 390 unload_nls(sbi->nls_io); 391 sbi->nls_io = NULL; 392 } 393 if (sbi->options.iocharset != fat_default_iocharset) { 394 kfree(sbi->options.iocharset); 395 sbi->options.iocharset = fat_default_iocharset; 396 } 397 398 sb->s_fs_info = NULL; 399 kfree(sbi); 400 } 401 402 static kmem_cache_t *fat_inode_cachep; 403 404 static struct inode *fat_alloc_inode(struct super_block *sb) 405 { 406 struct msdos_inode_info *ei; 407 ei = kmem_cache_alloc(fat_inode_cachep, SLAB_KERNEL); 408 if (!ei) 409 return NULL; 410 return &ei->vfs_inode; 411 } 412 413 static void fat_destroy_inode(struct inode *inode) 414 { 415 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode)); 416 } 417 418 static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags) 419 { 420 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo; 421 422 if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == 423 SLAB_CTOR_CONSTRUCTOR) { 424 spin_lock_init(&ei->cache_lru_lock); 425 ei->nr_caches = 0; 426 ei->cache_valid_id = FAT_CACHE_VALID + 1; 427 INIT_LIST_HEAD(&ei->cache_lru); 428 INIT_HLIST_NODE(&ei->i_fat_hash); 429 inode_init_once(&ei->vfs_inode); 430 } 431 } 432 433 static int __init fat_init_inodecache(void) 434 { 435 fat_inode_cachep = kmem_cache_create("fat_inode_cache", 436 sizeof(struct msdos_inode_info), 437 0, SLAB_RECLAIM_ACCOUNT, 438 init_once, NULL); 439 if (fat_inode_cachep == NULL) 440 return -ENOMEM; 441 return 0; 442 } 443 444 static void __exit fat_destroy_inodecache(void) 445 { 446 if (kmem_cache_destroy(fat_inode_cachep)) 447 printk(KERN_INFO "fat_inode_cache: not all structures were freed\n"); 448 } 449 450 static int fat_remount(struct super_block *sb, int *flags, char *data) 451 { 452 struct msdos_sb_info *sbi = MSDOS_SB(sb); 453 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME); 454 return 0; 455 } 456 457 static int fat_statfs(struct super_block *sb, struct kstatfs *buf) 458 { 459 struct msdos_sb_info *sbi = MSDOS_SB(sb); 460 461 /* If the count of free cluster is still unknown, counts it here. */ 462 if (sbi->free_clusters == -1) { 463 int err = fat_count_free_clusters(sb); 464 if (err) 465 return err; 466 } 467 468 buf->f_type = sb->s_magic; 469 buf->f_bsize = sbi->cluster_size; 470 buf->f_blocks = sbi->max_cluster - FAT_START_ENT; 471 buf->f_bfree = sbi->free_clusters; 472 buf->f_bavail = sbi->free_clusters; 473 buf->f_namelen = sbi->options.isvfat ? 260 : 12; 474 475 return 0; 476 } 477 478 static int fat_write_inode(struct inode *inode, int wait) 479 { 480 struct super_block *sb = inode->i_sb; 481 struct msdos_sb_info *sbi = MSDOS_SB(sb); 482 struct buffer_head *bh; 483 struct msdos_dir_entry *raw_entry; 484 loff_t i_pos; 485 int err = 0; 486 487 retry: 488 i_pos = MSDOS_I(inode)->i_pos; 489 if (inode->i_ino == MSDOS_ROOT_INO || !i_pos) 490 return 0; 491 492 lock_kernel(); 493 bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits); 494 if (!bh) { 495 printk(KERN_ERR "FAT: unable to read inode block " 496 "for updating (i_pos %lld)\n", i_pos); 497 err = -EIO; 498 goto out; 499 } 500 spin_lock(&sbi->inode_hash_lock); 501 if (i_pos != MSDOS_I(inode)->i_pos) { 502 spin_unlock(&sbi->inode_hash_lock); 503 brelse(bh); 504 unlock_kernel(); 505 goto retry; 506 } 507 508 raw_entry = &((struct msdos_dir_entry *) (bh->b_data)) 509 [i_pos & (sbi->dir_per_block - 1)]; 510 if (S_ISDIR(inode->i_mode)) 511 raw_entry->size = 0; 512 else 513 raw_entry->size = cpu_to_le32(inode->i_size); 514 raw_entry->attr = fat_attr(inode); 515 raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart); 516 raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16); 517 fat_date_unix2dos(inode->i_mtime.tv_sec, &raw_entry->time, &raw_entry->date); 518 if (sbi->options.isvfat) { 519 __le16 atime; 520 fat_date_unix2dos(inode->i_ctime.tv_sec,&raw_entry->ctime,&raw_entry->cdate); 521 fat_date_unix2dos(inode->i_atime.tv_sec,&atime,&raw_entry->adate); 522 raw_entry->ctime_cs = (inode->i_ctime.tv_sec & 1) * 100 + 523 inode->i_ctime.tv_nsec / 10000000; 524 } 525 spin_unlock(&sbi->inode_hash_lock); 526 mark_buffer_dirty(bh); 527 if (wait) 528 err = sync_dirty_buffer(bh); 529 brelse(bh); 530 out: 531 unlock_kernel(); 532 return err; 533 } 534 535 int fat_sync_inode(struct inode *inode) 536 { 537 return fat_write_inode(inode, 1); 538 } 539 540 EXPORT_SYMBOL(fat_sync_inode); 541 542 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt); 543 static struct super_operations fat_sops = { 544 .alloc_inode = fat_alloc_inode, 545 .destroy_inode = fat_destroy_inode, 546 .write_inode = fat_write_inode, 547 .delete_inode = fat_delete_inode, 548 .put_super = fat_put_super, 549 .statfs = fat_statfs, 550 .clear_inode = fat_clear_inode, 551 .remount_fs = fat_remount, 552 553 .read_inode = make_bad_inode, 554 555 .show_options = fat_show_options, 556 }; 557 558 /* 559 * a FAT file handle with fhtype 3 is 560 * 0/ i_ino - for fast, reliable lookup if still in the cache 561 * 1/ i_generation - to see if i_ino is still valid 562 * bit 0 == 0 iff directory 563 * 2/ i_pos(8-39) - if ino has changed, but still in cache 564 * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos 565 * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc 566 * 567 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum 568 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits 569 * of i_logstart is used to store the directory entry offset. 570 */ 571 572 static struct dentry * 573 fat_decode_fh(struct super_block *sb, __u32 *fh, int len, int fhtype, 574 int (*acceptable)(void *context, struct dentry *de), 575 void *context) 576 { 577 if (fhtype != 3) 578 return ERR_PTR(-ESTALE); 579 if (len < 5) 580 return ERR_PTR(-ESTALE); 581 582 return sb->s_export_op->find_exported_dentry(sb, fh, NULL, acceptable, context); 583 } 584 585 static struct dentry *fat_get_dentry(struct super_block *sb, void *inump) 586 { 587 struct inode *inode = NULL; 588 struct dentry *result; 589 __u32 *fh = inump; 590 591 inode = iget(sb, fh[0]); 592 if (!inode || is_bad_inode(inode) || inode->i_generation != fh[1]) { 593 if (inode) 594 iput(inode); 595 inode = NULL; 596 } 597 if (!inode) { 598 loff_t i_pos; 599 int i_logstart = fh[3] & 0x0fffffff; 600 601 i_pos = (loff_t)fh[2] << 8; 602 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28); 603 604 /* try 2 - see if i_pos is in F-d-c 605 * require i_logstart to be the same 606 * Will fail if you truncate and then re-write 607 */ 608 609 inode = fat_iget(sb, i_pos); 610 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) { 611 iput(inode); 612 inode = NULL; 613 } 614 } 615 if (!inode) { 616 /* For now, do nothing 617 * What we could do is: 618 * follow the file starting at fh[4], and record 619 * the ".." entry, and the name of the fh[2] entry. 620 * The follow the ".." file finding the next step up. 621 * This way we build a path to the root of 622 * the tree. If this works, we lookup the path and so 623 * get this inode into the cache. 624 * Finally try the fat_iget lookup again 625 * If that fails, then weare totally out of luck 626 * But all that is for another day 627 */ 628 } 629 if (!inode) 630 return ERR_PTR(-ESTALE); 631 632 633 /* now to find a dentry. 634 * If possible, get a well-connected one 635 */ 636 result = d_alloc_anon(inode); 637 if (result == NULL) { 638 iput(inode); 639 return ERR_PTR(-ENOMEM); 640 } 641 result->d_op = sb->s_root->d_op; 642 return result; 643 } 644 645 static int 646 fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable) 647 { 648 int len = *lenp; 649 struct inode *inode = de->d_inode; 650 u32 ipos_h, ipos_m, ipos_l; 651 652 if (len < 5) 653 return 255; /* no room */ 654 655 ipos_h = MSDOS_I(inode)->i_pos >> 8; 656 ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24; 657 ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28; 658 *lenp = 5; 659 fh[0] = inode->i_ino; 660 fh[1] = inode->i_generation; 661 fh[2] = ipos_h; 662 fh[3] = ipos_m | MSDOS_I(inode)->i_logstart; 663 spin_lock(&de->d_lock); 664 fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart; 665 spin_unlock(&de->d_lock); 666 return 3; 667 } 668 669 static struct dentry *fat_get_parent(struct dentry *child) 670 { 671 struct buffer_head *bh; 672 struct msdos_dir_entry *de; 673 loff_t i_pos; 674 struct dentry *parent; 675 struct inode *inode; 676 int err; 677 678 lock_kernel(); 679 680 err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos); 681 if (err) { 682 parent = ERR_PTR(err); 683 goto out; 684 } 685 inode = fat_build_inode(child->d_sb, de, i_pos); 686 brelse(bh); 687 if (IS_ERR(inode)) { 688 parent = ERR_PTR(PTR_ERR(inode)); 689 goto out; 690 } 691 parent = d_alloc_anon(inode); 692 if (!parent) { 693 iput(inode); 694 parent = ERR_PTR(-ENOMEM); 695 } 696 out: 697 unlock_kernel(); 698 699 return parent; 700 } 701 702 static struct export_operations fat_export_ops = { 703 .decode_fh = fat_decode_fh, 704 .encode_fh = fat_encode_fh, 705 .get_dentry = fat_get_dentry, 706 .get_parent = fat_get_parent, 707 }; 708 709 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt) 710 { 711 struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb); 712 struct fat_mount_options *opts = &sbi->options; 713 int isvfat = opts->isvfat; 714 715 if (opts->fs_uid != 0) 716 seq_printf(m, ",uid=%u", opts->fs_uid); 717 if (opts->fs_gid != 0) 718 seq_printf(m, ",gid=%u", opts->fs_gid); 719 seq_printf(m, ",fmask=%04o", opts->fs_fmask); 720 seq_printf(m, ",dmask=%04o", opts->fs_dmask); 721 if (sbi->nls_disk) 722 seq_printf(m, ",codepage=%s", sbi->nls_disk->charset); 723 if (isvfat) { 724 if (sbi->nls_io) 725 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset); 726 727 switch (opts->shortname) { 728 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95: 729 seq_puts(m, ",shortname=win95"); 730 break; 731 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT: 732 seq_puts(m, ",shortname=winnt"); 733 break; 734 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95: 735 seq_puts(m, ",shortname=mixed"); 736 break; 737 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95: 738 /* seq_puts(m, ",shortname=lower"); */ 739 break; 740 default: 741 seq_puts(m, ",shortname=unknown"); 742 break; 743 } 744 } 745 if (opts->name_check != 'n') 746 seq_printf(m, ",check=%c", opts->name_check); 747 if (opts->quiet) 748 seq_puts(m, ",quiet"); 749 if (opts->showexec) 750 seq_puts(m, ",showexec"); 751 if (opts->sys_immutable) 752 seq_puts(m, ",sys_immutable"); 753 if (!isvfat) { 754 if (opts->dotsOK) 755 seq_puts(m, ",dotsOK=yes"); 756 if (opts->nocase) 757 seq_puts(m, ",nocase"); 758 } else { 759 if (opts->utf8) 760 seq_puts(m, ",utf8"); 761 if (opts->unicode_xlate) 762 seq_puts(m, ",uni_xlate"); 763 if (!opts->numtail) 764 seq_puts(m, ",nonumtail"); 765 } 766 767 return 0; 768 } 769 770 enum { 771 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid, 772 Opt_umask, Opt_dmask, Opt_fmask, Opt_codepage, Opt_nocase, 773 Opt_quiet, Opt_showexec, Opt_debug, Opt_immutable, 774 Opt_dots, Opt_nodots, 775 Opt_charset, Opt_shortname_lower, Opt_shortname_win95, 776 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes, 777 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes, 778 Opt_obsolate, Opt_err, 779 }; 780 781 static match_table_t fat_tokens = { 782 {Opt_check_r, "check=relaxed"}, 783 {Opt_check_s, "check=strict"}, 784 {Opt_check_n, "check=normal"}, 785 {Opt_check_r, "check=r"}, 786 {Opt_check_s, "check=s"}, 787 {Opt_check_n, "check=n"}, 788 {Opt_uid, "uid=%u"}, 789 {Opt_gid, "gid=%u"}, 790 {Opt_umask, "umask=%o"}, 791 {Opt_dmask, "dmask=%o"}, 792 {Opt_fmask, "fmask=%o"}, 793 {Opt_codepage, "codepage=%u"}, 794 {Opt_nocase, "nocase"}, 795 {Opt_quiet, "quiet"}, 796 {Opt_showexec, "showexec"}, 797 {Opt_debug, "debug"}, 798 {Opt_immutable, "sys_immutable"}, 799 {Opt_obsolate, "conv=binary"}, 800 {Opt_obsolate, "conv=text"}, 801 {Opt_obsolate, "conv=auto"}, 802 {Opt_obsolate, "conv=b"}, 803 {Opt_obsolate, "conv=t"}, 804 {Opt_obsolate, "conv=a"}, 805 {Opt_obsolate, "fat=%u"}, 806 {Opt_obsolate, "blocksize=%u"}, 807 {Opt_obsolate, "cvf_format=%20s"}, 808 {Opt_obsolate, "cvf_options=%100s"}, 809 {Opt_obsolate, "posix"}, 810 {Opt_err, NULL} 811 }; 812 static match_table_t msdos_tokens = { 813 {Opt_nodots, "nodots"}, 814 {Opt_nodots, "dotsOK=no"}, 815 {Opt_dots, "dots"}, 816 {Opt_dots, "dotsOK=yes"}, 817 {Opt_err, NULL} 818 }; 819 static match_table_t vfat_tokens = { 820 {Opt_charset, "iocharset=%s"}, 821 {Opt_shortname_lower, "shortname=lower"}, 822 {Opt_shortname_win95, "shortname=win95"}, 823 {Opt_shortname_winnt, "shortname=winnt"}, 824 {Opt_shortname_mixed, "shortname=mixed"}, 825 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */ 826 {Opt_utf8_no, "utf8=no"}, 827 {Opt_utf8_no, "utf8=false"}, 828 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */ 829 {Opt_utf8_yes, "utf8=yes"}, 830 {Opt_utf8_yes, "utf8=true"}, 831 {Opt_utf8_yes, "utf8"}, 832 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */ 833 {Opt_uni_xl_no, "uni_xlate=no"}, 834 {Opt_uni_xl_no, "uni_xlate=false"}, 835 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */ 836 {Opt_uni_xl_yes, "uni_xlate=yes"}, 837 {Opt_uni_xl_yes, "uni_xlate=true"}, 838 {Opt_uni_xl_yes, "uni_xlate"}, 839 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */ 840 {Opt_nonumtail_no, "nonumtail=no"}, 841 {Opt_nonumtail_no, "nonumtail=false"}, 842 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */ 843 {Opt_nonumtail_yes, "nonumtail=yes"}, 844 {Opt_nonumtail_yes, "nonumtail=true"}, 845 {Opt_nonumtail_yes, "nonumtail"}, 846 {Opt_err, NULL} 847 }; 848 849 static int parse_options(char *options, int is_vfat, int *debug, 850 struct fat_mount_options *opts) 851 { 852 char *p; 853 substring_t args[MAX_OPT_ARGS]; 854 int option; 855 char *iocharset; 856 857 opts->isvfat = is_vfat; 858 859 opts->fs_uid = current->uid; 860 opts->fs_gid = current->gid; 861 opts->fs_fmask = opts->fs_dmask = current->fs->umask; 862 opts->codepage = fat_default_codepage; 863 opts->iocharset = fat_default_iocharset; 864 if (is_vfat) 865 opts->shortname = VFAT_SFN_DISPLAY_LOWER|VFAT_SFN_CREATE_WIN95; 866 else 867 opts->shortname = 0; 868 opts->name_check = 'n'; 869 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0; 870 opts->utf8 = opts->unicode_xlate = 0; 871 opts->numtail = 1; 872 opts->nocase = 0; 873 *debug = 0; 874 875 if (!options) 876 return 0; 877 878 while ((p = strsep(&options, ",")) != NULL) { 879 int token; 880 if (!*p) 881 continue; 882 883 token = match_token(p, fat_tokens, args); 884 if (token == Opt_err) { 885 if (is_vfat) 886 token = match_token(p, vfat_tokens, args); 887 else 888 token = match_token(p, msdos_tokens, args); 889 } 890 switch (token) { 891 case Opt_check_s: 892 opts->name_check = 's'; 893 break; 894 case Opt_check_r: 895 opts->name_check = 'r'; 896 break; 897 case Opt_check_n: 898 opts->name_check = 'n'; 899 break; 900 case Opt_nocase: 901 if (!is_vfat) 902 opts->nocase = 1; 903 else { 904 /* for backward compatibility */ 905 opts->shortname = VFAT_SFN_DISPLAY_WIN95 906 | VFAT_SFN_CREATE_WIN95; 907 } 908 break; 909 case Opt_quiet: 910 opts->quiet = 1; 911 break; 912 case Opt_showexec: 913 opts->showexec = 1; 914 break; 915 case Opt_debug: 916 *debug = 1; 917 break; 918 case Opt_immutable: 919 opts->sys_immutable = 1; 920 break; 921 case Opt_uid: 922 if (match_int(&args[0], &option)) 923 return 0; 924 opts->fs_uid = option; 925 break; 926 case Opt_gid: 927 if (match_int(&args[0], &option)) 928 return 0; 929 opts->fs_gid = option; 930 break; 931 case Opt_umask: 932 if (match_octal(&args[0], &option)) 933 return 0; 934 opts->fs_fmask = opts->fs_dmask = option; 935 break; 936 case Opt_dmask: 937 if (match_octal(&args[0], &option)) 938 return 0; 939 opts->fs_dmask = option; 940 break; 941 case Opt_fmask: 942 if (match_octal(&args[0], &option)) 943 return 0; 944 opts->fs_fmask = option; 945 break; 946 case Opt_codepage: 947 if (match_int(&args[0], &option)) 948 return 0; 949 opts->codepage = option; 950 break; 951 952 /* msdos specific */ 953 case Opt_dots: 954 opts->dotsOK = 1; 955 break; 956 case Opt_nodots: 957 opts->dotsOK = 0; 958 break; 959 960 /* vfat specific */ 961 case Opt_charset: 962 if (opts->iocharset != fat_default_iocharset) 963 kfree(opts->iocharset); 964 iocharset = match_strdup(&args[0]); 965 if (!iocharset) 966 return -ENOMEM; 967 opts->iocharset = iocharset; 968 break; 969 case Opt_shortname_lower: 970 opts->shortname = VFAT_SFN_DISPLAY_LOWER 971 | VFAT_SFN_CREATE_WIN95; 972 break; 973 case Opt_shortname_win95: 974 opts->shortname = VFAT_SFN_DISPLAY_WIN95 975 | VFAT_SFN_CREATE_WIN95; 976 break; 977 case Opt_shortname_winnt: 978 opts->shortname = VFAT_SFN_DISPLAY_WINNT 979 | VFAT_SFN_CREATE_WINNT; 980 break; 981 case Opt_shortname_mixed: 982 opts->shortname = VFAT_SFN_DISPLAY_WINNT 983 | VFAT_SFN_CREATE_WIN95; 984 break; 985 case Opt_utf8_no: /* 0 or no or false */ 986 opts->utf8 = 0; 987 break; 988 case Opt_utf8_yes: /* empty or 1 or yes or true */ 989 opts->utf8 = 1; 990 break; 991 case Opt_uni_xl_no: /* 0 or no or false */ 992 opts->unicode_xlate = 0; 993 break; 994 case Opt_uni_xl_yes: /* empty or 1 or yes or true */ 995 opts->unicode_xlate = 1; 996 break; 997 case Opt_nonumtail_no: /* 0 or no or false */ 998 opts->numtail = 1; /* negated option */ 999 break; 1000 case Opt_nonumtail_yes: /* empty or 1 or yes or true */ 1001 opts->numtail = 0; /* negated option */ 1002 break; 1003 1004 /* obsolete mount options */ 1005 case Opt_obsolate: 1006 printk(KERN_INFO "FAT: \"%s\" option is obsolete, " 1007 "not supported now\n", p); 1008 break; 1009 /* unknown option */ 1010 default: 1011 printk(KERN_ERR "FAT: Unrecognized mount option \"%s\" " 1012 "or missing value\n", p); 1013 return -EINVAL; 1014 } 1015 } 1016 /* UTF8 doesn't provide FAT semantics */ 1017 if (!strcmp(opts->iocharset, "utf8")) { 1018 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset" 1019 " for FAT filesystems, filesystem will be case sensitive!\n"); 1020 } 1021 1022 if (opts->unicode_xlate) 1023 opts->utf8 = 0; 1024 1025 return 0; 1026 } 1027 1028 static int fat_read_root(struct inode *inode) 1029 { 1030 struct super_block *sb = inode->i_sb; 1031 struct msdos_sb_info *sbi = MSDOS_SB(sb); 1032 int error; 1033 1034 MSDOS_I(inode)->i_pos = 0; 1035 inode->i_uid = sbi->options.fs_uid; 1036 inode->i_gid = sbi->options.fs_gid; 1037 inode->i_version++; 1038 inode->i_generation = 0; 1039 inode->i_mode = (S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR; 1040 inode->i_op = sbi->dir_ops; 1041 inode->i_fop = &fat_dir_operations; 1042 if (sbi->fat_bits == 32) { 1043 MSDOS_I(inode)->i_start = sbi->root_cluster; 1044 error = fat_calc_dir_size(inode); 1045 if (error < 0) 1046 return error; 1047 } else { 1048 MSDOS_I(inode)->i_start = 0; 1049 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry); 1050 } 1051 inode->i_blksize = sbi->cluster_size; 1052 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 1053 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 1054 MSDOS_I(inode)->i_logstart = 0; 1055 MSDOS_I(inode)->mmu_private = inode->i_size; 1056 1057 MSDOS_I(inode)->i_attrs = ATTR_NONE; 1058 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0; 1059 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0; 1060 inode->i_nlink = fat_subdirs(inode)+2; 1061 1062 return 0; 1063 } 1064 1065 /* 1066 * Read the super block of an MS-DOS FS. 1067 */ 1068 int fat_fill_super(struct super_block *sb, void *data, int silent, 1069 struct inode_operations *fs_dir_inode_ops, int isvfat) 1070 { 1071 struct inode *root_inode = NULL; 1072 struct buffer_head *bh; 1073 struct fat_boot_sector *b; 1074 struct msdos_sb_info *sbi; 1075 u16 logical_sector_size; 1076 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors; 1077 int debug; 1078 unsigned int media; 1079 long error; 1080 char buf[50]; 1081 1082 sbi = kmalloc(sizeof(struct msdos_sb_info), GFP_KERNEL); 1083 if (!sbi) 1084 return -ENOMEM; 1085 sb->s_fs_info = sbi; 1086 memset(sbi, 0, sizeof(struct msdos_sb_info)); 1087 1088 sb->s_flags |= MS_NODIRATIME; 1089 sb->s_magic = MSDOS_SUPER_MAGIC; 1090 sb->s_op = &fat_sops; 1091 sb->s_export_op = &fat_export_ops; 1092 sbi->dir_ops = fs_dir_inode_ops; 1093 1094 error = parse_options(data, isvfat, &debug, &sbi->options); 1095 if (error) 1096 goto out_fail; 1097 1098 error = -EIO; 1099 sb_min_blocksize(sb, 512); 1100 bh = sb_bread(sb, 0); 1101 if (bh == NULL) { 1102 printk(KERN_ERR "FAT: unable to read boot sector\n"); 1103 goto out_fail; 1104 } 1105 1106 b = (struct fat_boot_sector *) bh->b_data; 1107 if (!b->reserved) { 1108 if (!silent) 1109 printk(KERN_ERR "FAT: bogus number of reserved sectors\n"); 1110 brelse(bh); 1111 goto out_invalid; 1112 } 1113 if (!b->fats) { 1114 if (!silent) 1115 printk(KERN_ERR "FAT: bogus number of FAT structure\n"); 1116 brelse(bh); 1117 goto out_invalid; 1118 } 1119 1120 /* 1121 * Earlier we checked here that b->secs_track and b->head are nonzero, 1122 * but it turns out valid FAT filesystems can have zero there. 1123 */ 1124 1125 media = b->media; 1126 if (!FAT_VALID_MEDIA(media)) { 1127 if (!silent) 1128 printk(KERN_ERR "FAT: invalid media value (0x%02x)\n", 1129 media); 1130 brelse(bh); 1131 goto out_invalid; 1132 } 1133 logical_sector_size = 1134 le16_to_cpu(get_unaligned((__le16 *)&b->sector_size)); 1135 if (!logical_sector_size 1136 || (logical_sector_size & (logical_sector_size - 1)) 1137 || (logical_sector_size < 512) 1138 || (PAGE_CACHE_SIZE < logical_sector_size)) { 1139 if (!silent) 1140 printk(KERN_ERR "FAT: bogus logical sector size %u\n", 1141 logical_sector_size); 1142 brelse(bh); 1143 goto out_invalid; 1144 } 1145 sbi->sec_per_clus = b->sec_per_clus; 1146 if (!sbi->sec_per_clus 1147 || (sbi->sec_per_clus & (sbi->sec_per_clus - 1))) { 1148 if (!silent) 1149 printk(KERN_ERR "FAT: bogus sectors per cluster %u\n", 1150 sbi->sec_per_clus); 1151 brelse(bh); 1152 goto out_invalid; 1153 } 1154 1155 if (logical_sector_size < sb->s_blocksize) { 1156 printk(KERN_ERR "FAT: logical sector size too small for device" 1157 " (logical sector size = %u)\n", logical_sector_size); 1158 brelse(bh); 1159 goto out_fail; 1160 } 1161 if (logical_sector_size > sb->s_blocksize) { 1162 brelse(bh); 1163 1164 if (!sb_set_blocksize(sb, logical_sector_size)) { 1165 printk(KERN_ERR "FAT: unable to set blocksize %u\n", 1166 logical_sector_size); 1167 goto out_fail; 1168 } 1169 bh = sb_bread(sb, 0); 1170 if (bh == NULL) { 1171 printk(KERN_ERR "FAT: unable to read boot sector" 1172 " (logical sector size = %lu)\n", 1173 sb->s_blocksize); 1174 goto out_fail; 1175 } 1176 b = (struct fat_boot_sector *) bh->b_data; 1177 } 1178 1179 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus; 1180 sbi->cluster_bits = ffs(sbi->cluster_size) - 1; 1181 sbi->fats = b->fats; 1182 sbi->fat_bits = 0; /* Don't know yet */ 1183 sbi->fat_start = le16_to_cpu(b->reserved); 1184 sbi->fat_length = le16_to_cpu(b->fat_length); 1185 sbi->root_cluster = 0; 1186 sbi->free_clusters = -1; /* Don't know yet */ 1187 sbi->prev_free = FAT_START_ENT; 1188 1189 if (!sbi->fat_length && b->fat32_length) { 1190 struct fat_boot_fsinfo *fsinfo; 1191 struct buffer_head *fsinfo_bh; 1192 1193 /* Must be FAT32 */ 1194 sbi->fat_bits = 32; 1195 sbi->fat_length = le32_to_cpu(b->fat32_length); 1196 sbi->root_cluster = le32_to_cpu(b->root_cluster); 1197 1198 sb->s_maxbytes = 0xffffffff; 1199 1200 /* MC - if info_sector is 0, don't multiply by 0 */ 1201 sbi->fsinfo_sector = le16_to_cpu(b->info_sector); 1202 if (sbi->fsinfo_sector == 0) 1203 sbi->fsinfo_sector = 1; 1204 1205 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector); 1206 if (fsinfo_bh == NULL) { 1207 printk(KERN_ERR "FAT: bread failed, FSINFO block" 1208 " (sector = %lu)\n", sbi->fsinfo_sector); 1209 brelse(bh); 1210 goto out_fail; 1211 } 1212 1213 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data; 1214 if (!IS_FSINFO(fsinfo)) { 1215 printk(KERN_WARNING 1216 "FAT: Did not find valid FSINFO signature.\n" 1217 " Found signature1 0x%08x signature2 0x%08x" 1218 " (sector = %lu)\n", 1219 le32_to_cpu(fsinfo->signature1), 1220 le32_to_cpu(fsinfo->signature2), 1221 sbi->fsinfo_sector); 1222 } else { 1223 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters); 1224 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster); 1225 } 1226 1227 brelse(fsinfo_bh); 1228 } 1229 1230 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry); 1231 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1; 1232 1233 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length; 1234 sbi->dir_entries = 1235 le16_to_cpu(get_unaligned((__le16 *)&b->dir_entries)); 1236 if (sbi->dir_entries & (sbi->dir_per_block - 1)) { 1237 if (!silent) 1238 printk(KERN_ERR "FAT: bogus directroy-entries per block" 1239 " (%u)\n", sbi->dir_entries); 1240 brelse(bh); 1241 goto out_invalid; 1242 } 1243 1244 rootdir_sectors = sbi->dir_entries 1245 * sizeof(struct msdos_dir_entry) / sb->s_blocksize; 1246 sbi->data_start = sbi->dir_start + rootdir_sectors; 1247 total_sectors = le16_to_cpu(get_unaligned((__le16 *)&b->sectors)); 1248 if (total_sectors == 0) 1249 total_sectors = le32_to_cpu(b->total_sect); 1250 1251 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus; 1252 1253 if (sbi->fat_bits != 32) 1254 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12; 1255 1256 /* check that FAT table does not overflow */ 1257 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits; 1258 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT); 1259 if (total_clusters > MAX_FAT(sb)) { 1260 if (!silent) 1261 printk(KERN_ERR "FAT: count of clusters too big (%u)\n", 1262 total_clusters); 1263 brelse(bh); 1264 goto out_invalid; 1265 } 1266 1267 sbi->max_cluster = total_clusters + FAT_START_ENT; 1268 /* check the free_clusters, it's not necessarily correct */ 1269 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters) 1270 sbi->free_clusters = -1; 1271 /* check the prev_free, it's not necessarily correct */ 1272 sbi->prev_free %= sbi->max_cluster; 1273 if (sbi->prev_free < FAT_START_ENT) 1274 sbi->prev_free = FAT_START_ENT; 1275 1276 brelse(bh); 1277 1278 /* set up enough so that it can read an inode */ 1279 fat_hash_init(sb); 1280 fat_ent_access_init(sb); 1281 1282 /* 1283 * The low byte of FAT's first entry must have same value with 1284 * media-field. But in real world, too many devices is 1285 * writing wrong value. So, removed that validity check. 1286 * 1287 * if (FAT_FIRST_ENT(sb, media) != first) 1288 */ 1289 1290 error = -EINVAL; 1291 sprintf(buf, "cp%d", sbi->options.codepage); 1292 sbi->nls_disk = load_nls(buf); 1293 if (!sbi->nls_disk) { 1294 printk(KERN_ERR "FAT: codepage %s not found\n", buf); 1295 goto out_fail; 1296 } 1297 1298 /* FIXME: utf8 is using iocharset for upper/lower conversion */ 1299 if (sbi->options.isvfat) { 1300 sbi->nls_io = load_nls(sbi->options.iocharset); 1301 if (!sbi->nls_io) { 1302 printk(KERN_ERR "FAT: IO charset %s not found\n", 1303 sbi->options.iocharset); 1304 goto out_fail; 1305 } 1306 } 1307 1308 error = -ENOMEM; 1309 root_inode = new_inode(sb); 1310 if (!root_inode) 1311 goto out_fail; 1312 root_inode->i_ino = MSDOS_ROOT_INO; 1313 root_inode->i_version = 1; 1314 error = fat_read_root(root_inode); 1315 if (error < 0) 1316 goto out_fail; 1317 error = -ENOMEM; 1318 insert_inode_hash(root_inode); 1319 sb->s_root = d_alloc_root(root_inode); 1320 if (!sb->s_root) { 1321 printk(KERN_ERR "FAT: get root inode failed\n"); 1322 goto out_fail; 1323 } 1324 1325 return 0; 1326 1327 out_invalid: 1328 error = -EINVAL; 1329 if (!silent) 1330 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem" 1331 " on dev %s.\n", sb->s_id); 1332 1333 out_fail: 1334 if (root_inode) 1335 iput(root_inode); 1336 if (sbi->nls_io) 1337 unload_nls(sbi->nls_io); 1338 if (sbi->nls_disk) 1339 unload_nls(sbi->nls_disk); 1340 if (sbi->options.iocharset != fat_default_iocharset) 1341 kfree(sbi->options.iocharset); 1342 sb->s_fs_info = NULL; 1343 kfree(sbi); 1344 return error; 1345 } 1346 1347 EXPORT_SYMBOL(fat_fill_super); 1348 1349 int __init fat_cache_init(void); 1350 void fat_cache_destroy(void); 1351 1352 static int __init init_fat_fs(void) 1353 { 1354 int err; 1355 1356 err = fat_cache_init(); 1357 if (err) 1358 return err; 1359 1360 err = fat_init_inodecache(); 1361 if (err) 1362 goto failed; 1363 1364 return 0; 1365 1366 failed: 1367 fat_cache_destroy(); 1368 return err; 1369 } 1370 1371 static void __exit exit_fat_fs(void) 1372 { 1373 fat_cache_destroy(); 1374 fat_destroy_inodecache(); 1375 } 1376 1377 module_init(init_fat_fs) 1378 module_exit(exit_fat_fs) 1379 1380 MODULE_LICENSE("GPL"); 1381