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/mpage.h> 22 #include <linux/buffer_head.h> 23 #include <linux/mount.h> 24 #include <linux/vfs.h> 25 #include <linux/parser.h> 26 #include <linux/uio.h> 27 #include <asm/unaligned.h> 28 29 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET 30 /* if user don't select VFAT, this is undefined. */ 31 #define CONFIG_FAT_DEFAULT_IOCHARSET "" 32 #endif 33 34 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE; 35 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET; 36 37 38 static int fat_add_cluster(struct inode *inode) 39 { 40 int err, cluster; 41 42 err = fat_alloc_clusters(inode, &cluster, 1); 43 if (err) 44 return err; 45 /* FIXME: this cluster should be added after data of this 46 * cluster is writed */ 47 err = fat_chain_add(inode, cluster, 1); 48 if (err) 49 fat_free_clusters(inode, cluster); 50 return err; 51 } 52 53 static int __fat_get_blocks(struct inode *inode, sector_t iblock, 54 unsigned long *max_blocks, 55 struct buffer_head *bh_result, int create) 56 { 57 struct super_block *sb = inode->i_sb; 58 struct msdos_sb_info *sbi = MSDOS_SB(sb); 59 sector_t phys; 60 unsigned long mapped_blocks; 61 int err, offset; 62 63 err = fat_bmap(inode, iblock, &phys, &mapped_blocks); 64 if (err) 65 return err; 66 if (phys) { 67 map_bh(bh_result, sb, phys); 68 *max_blocks = min(mapped_blocks, *max_blocks); 69 return 0; 70 } 71 if (!create) 72 return 0; 73 74 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) { 75 fat_fs_panic(sb, "corrupted file size (i_pos %lld, %lld)", 76 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private); 77 return -EIO; 78 } 79 80 offset = (unsigned long)iblock & (sbi->sec_per_clus - 1); 81 if (!offset) { 82 /* TODO: multiple cluster allocation would be desirable. */ 83 err = fat_add_cluster(inode); 84 if (err) 85 return err; 86 } 87 /* available blocks on this cluster */ 88 mapped_blocks = sbi->sec_per_clus - offset; 89 90 *max_blocks = min(mapped_blocks, *max_blocks); 91 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits; 92 93 err = fat_bmap(inode, iblock, &phys, &mapped_blocks); 94 if (err) 95 return err; 96 BUG_ON(!phys); 97 BUG_ON(*max_blocks != mapped_blocks); 98 set_buffer_new(bh_result); 99 map_bh(bh_result, sb, phys); 100 return 0; 101 } 102 103 static int fat_get_blocks(struct inode *inode, sector_t iblock, 104 struct buffer_head *bh_result, int create) 105 { 106 struct super_block *sb = inode->i_sb; 107 int err; 108 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits; 109 110 err = __fat_get_blocks(inode, iblock, &max_blocks, bh_result, create); 111 if (err) 112 return err; 113 bh_result->b_size = max_blocks << sb->s_blocksize_bits; 114 return 0; 115 } 116 117 static int fat_get_block(struct inode *inode, sector_t iblock, 118 struct buffer_head *bh_result, int create) 119 { 120 unsigned long max_blocks = 1; 121 return __fat_get_blocks(inode, iblock, &max_blocks, bh_result, create); 122 } 123 124 static int fat_writepage(struct page *page, struct writeback_control *wbc) 125 { 126 return block_write_full_page(page, fat_get_block, wbc); 127 } 128 129 static int fat_writepages(struct address_space *mapping, 130 struct writeback_control *wbc) 131 { 132 return mpage_writepages(mapping, wbc, fat_get_block); 133 } 134 135 static int fat_readpage(struct file *file, struct page *page) 136 { 137 return mpage_readpage(page, fat_get_block); 138 } 139 140 static int fat_readpages(struct file *file, struct address_space *mapping, 141 struct list_head *pages, unsigned nr_pages) 142 { 143 return mpage_readpages(mapping, pages, nr_pages, fat_get_block); 144 } 145 146 static int fat_prepare_write(struct file *file, struct page *page, 147 unsigned from, unsigned to) 148 { 149 return cont_prepare_write(page, from, to, fat_get_block, 150 &MSDOS_I(page->mapping->host)->mmu_private); 151 } 152 153 static int fat_commit_write(struct file *file, struct page *page, 154 unsigned from, unsigned to) 155 { 156 struct inode *inode = page->mapping->host; 157 int err = generic_commit_write(file, page, from, to); 158 if (!err && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) { 159 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC; 160 MSDOS_I(inode)->i_attrs |= ATTR_ARCH; 161 mark_inode_dirty(inode); 162 } 163 return err; 164 } 165 166 static ssize_t fat_direct_IO(int rw, struct kiocb *iocb, 167 const struct iovec *iov, 168 loff_t offset, unsigned long nr_segs) 169 { 170 struct file *file = iocb->ki_filp; 171 struct inode *inode = file->f_mapping->host; 172 173 if (rw == WRITE) { 174 /* 175 * FIXME: blockdev_direct_IO() doesn't use ->prepare_write(), 176 * so we need to update the ->mmu_private to block boundary. 177 * 178 * But we must fill the remaining area or hole by nul for 179 * updating ->mmu_private. 180 */ 181 loff_t size = offset + iov_length(iov, nr_segs); 182 if (MSDOS_I(inode)->mmu_private < size) 183 return -EINVAL; 184 } 185 186 /* 187 * FAT need to use the DIO_LOCKING for avoiding the race 188 * condition of fat_get_block() and ->truncate(). 189 */ 190 return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov, 191 offset, nr_segs, fat_get_blocks, NULL); 192 } 193 194 static sector_t _fat_bmap(struct address_space *mapping, sector_t block) 195 { 196 return generic_block_bmap(mapping, block, fat_get_block); 197 } 198 199 static const struct address_space_operations fat_aops = { 200 .readpage = fat_readpage, 201 .readpages = fat_readpages, 202 .writepage = fat_writepage, 203 .writepages = fat_writepages, 204 .sync_page = block_sync_page, 205 .prepare_write = fat_prepare_write, 206 .commit_write = fat_commit_write, 207 .direct_IO = fat_direct_IO, 208 .bmap = _fat_bmap 209 }; 210 211 /* 212 * New FAT inode stuff. We do the following: 213 * a) i_ino is constant and has nothing with on-disk location. 214 * b) FAT manages its own cache of directory entries. 215 * c) *This* cache is indexed by on-disk location. 216 * d) inode has an associated directory entry, all right, but 217 * it may be unhashed. 218 * e) currently entries are stored within struct inode. That should 219 * change. 220 * f) we deal with races in the following way: 221 * 1. readdir() and lookup() do FAT-dir-cache lookup. 222 * 2. rename() unhashes the F-d-c entry and rehashes it in 223 * a new place. 224 * 3. unlink() and rmdir() unhash F-d-c entry. 225 * 4. fat_write_inode() checks whether the thing is unhashed. 226 * If it is we silently return. If it isn't we do bread(), 227 * check if the location is still valid and retry if it 228 * isn't. Otherwise we do changes. 229 * 5. Spinlock is used to protect hash/unhash/location check/lookup 230 * 6. fat_clear_inode() unhashes the F-d-c entry. 231 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry 232 * and consider negative result as cache miss. 233 */ 234 235 static void fat_hash_init(struct super_block *sb) 236 { 237 struct msdos_sb_info *sbi = MSDOS_SB(sb); 238 int i; 239 240 spin_lock_init(&sbi->inode_hash_lock); 241 for (i = 0; i < FAT_HASH_SIZE; i++) 242 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]); 243 } 244 245 static inline unsigned long fat_hash(struct super_block *sb, loff_t i_pos) 246 { 247 unsigned long tmp = (unsigned long)i_pos | (unsigned long) sb; 248 tmp = tmp + (tmp >> FAT_HASH_BITS) + (tmp >> FAT_HASH_BITS * 2); 249 return tmp & FAT_HASH_MASK; 250 } 251 252 void fat_attach(struct inode *inode, loff_t i_pos) 253 { 254 struct super_block *sb = inode->i_sb; 255 struct msdos_sb_info *sbi = MSDOS_SB(sb); 256 257 spin_lock(&sbi->inode_hash_lock); 258 MSDOS_I(inode)->i_pos = i_pos; 259 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, 260 sbi->inode_hashtable + fat_hash(sb, i_pos)); 261 spin_unlock(&sbi->inode_hash_lock); 262 } 263 264 EXPORT_SYMBOL_GPL(fat_attach); 265 266 void fat_detach(struct inode *inode) 267 { 268 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 269 spin_lock(&sbi->inode_hash_lock); 270 MSDOS_I(inode)->i_pos = 0; 271 hlist_del_init(&MSDOS_I(inode)->i_fat_hash); 272 spin_unlock(&sbi->inode_hash_lock); 273 } 274 275 EXPORT_SYMBOL_GPL(fat_detach); 276 277 struct inode *fat_iget(struct super_block *sb, loff_t i_pos) 278 { 279 struct msdos_sb_info *sbi = MSDOS_SB(sb); 280 struct hlist_head *head = sbi->inode_hashtable + fat_hash(sb, i_pos); 281 struct hlist_node *_p; 282 struct msdos_inode_info *i; 283 struct inode *inode = NULL; 284 285 spin_lock(&sbi->inode_hash_lock); 286 hlist_for_each_entry(i, _p, head, i_fat_hash) { 287 BUG_ON(i->vfs_inode.i_sb != sb); 288 if (i->i_pos != i_pos) 289 continue; 290 inode = igrab(&i->vfs_inode); 291 if (inode) 292 break; 293 } 294 spin_unlock(&sbi->inode_hash_lock); 295 return inode; 296 } 297 298 static int is_exec(unsigned char *extension) 299 { 300 unsigned char *exe_extensions = "EXECOMBAT", *walk; 301 302 for (walk = exe_extensions; *walk; walk += 3) 303 if (!strncmp(extension, walk, 3)) 304 return 1; 305 return 0; 306 } 307 308 static int fat_calc_dir_size(struct inode *inode) 309 { 310 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 311 int ret, fclus, dclus; 312 313 inode->i_size = 0; 314 if (MSDOS_I(inode)->i_start == 0) 315 return 0; 316 317 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); 318 if (ret < 0) 319 return ret; 320 inode->i_size = (fclus + 1) << sbi->cluster_bits; 321 322 return 0; 323 } 324 325 /* doesn't deal with root inode */ 326 static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de) 327 { 328 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 329 int error; 330 331 MSDOS_I(inode)->i_pos = 0; 332 inode->i_uid = sbi->options.fs_uid; 333 inode->i_gid = sbi->options.fs_gid; 334 inode->i_version++; 335 inode->i_generation = get_seconds(); 336 337 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) { 338 inode->i_generation &= ~1; 339 inode->i_mode = MSDOS_MKMODE(de->attr, 340 S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR; 341 inode->i_op = sbi->dir_ops; 342 inode->i_fop = &fat_dir_operations; 343 344 MSDOS_I(inode)->i_start = le16_to_cpu(de->start); 345 if (sbi->fat_bits == 32) 346 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16); 347 348 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 349 error = fat_calc_dir_size(inode); 350 if (error < 0) 351 return error; 352 MSDOS_I(inode)->mmu_private = inode->i_size; 353 354 inode->i_nlink = fat_subdirs(inode); 355 } else { /* not a directory */ 356 inode->i_generation |= 1; 357 inode->i_mode = MSDOS_MKMODE(de->attr, 358 ((sbi->options.showexec && 359 !is_exec(de->ext)) 360 ? S_IRUGO|S_IWUGO : S_IRWXUGO) 361 & ~sbi->options.fs_fmask) | S_IFREG; 362 MSDOS_I(inode)->i_start = le16_to_cpu(de->start); 363 if (sbi->fat_bits == 32) 364 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16); 365 366 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 367 inode->i_size = le32_to_cpu(de->size); 368 inode->i_op = &fat_file_inode_operations; 369 inode->i_fop = &fat_file_operations; 370 inode->i_mapping->a_ops = &fat_aops; 371 MSDOS_I(inode)->mmu_private = inode->i_size; 372 } 373 if (de->attr & ATTR_SYS) { 374 if (sbi->options.sys_immutable) 375 inode->i_flags |= S_IMMUTABLE; 376 } 377 MSDOS_I(inode)->i_attrs = de->attr & ATTR_UNUSED; 378 /* this is as close to the truth as we can get ... */ 379 inode->i_blksize = sbi->cluster_size; 380 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 381 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 382 inode->i_mtime.tv_sec = 383 date_dos2unix(le16_to_cpu(de->time), le16_to_cpu(de->date)); 384 inode->i_mtime.tv_nsec = 0; 385 if (sbi->options.isvfat) { 386 int secs = de->ctime_cs / 100; 387 int csecs = de->ctime_cs % 100; 388 inode->i_ctime.tv_sec = 389 date_dos2unix(le16_to_cpu(de->ctime), 390 le16_to_cpu(de->cdate)) + secs; 391 inode->i_ctime.tv_nsec = csecs * 10000000; 392 inode->i_atime.tv_sec = 393 date_dos2unix(le16_to_cpu(0), le16_to_cpu(de->adate)); 394 inode->i_atime.tv_nsec = 0; 395 } else 396 inode->i_ctime = inode->i_atime = inode->i_mtime; 397 398 return 0; 399 } 400 401 struct inode *fat_build_inode(struct super_block *sb, 402 struct msdos_dir_entry *de, loff_t i_pos) 403 { 404 struct inode *inode; 405 int err; 406 407 inode = fat_iget(sb, i_pos); 408 if (inode) 409 goto out; 410 inode = new_inode(sb); 411 if (!inode) { 412 inode = ERR_PTR(-ENOMEM); 413 goto out; 414 } 415 inode->i_ino = iunique(sb, MSDOS_ROOT_INO); 416 inode->i_version = 1; 417 err = fat_fill_inode(inode, de); 418 if (err) { 419 iput(inode); 420 inode = ERR_PTR(err); 421 goto out; 422 } 423 fat_attach(inode, i_pos); 424 insert_inode_hash(inode); 425 out: 426 return inode; 427 } 428 429 EXPORT_SYMBOL_GPL(fat_build_inode); 430 431 static void fat_delete_inode(struct inode *inode) 432 { 433 truncate_inode_pages(&inode->i_data, 0); 434 435 if (!is_bad_inode(inode)) { 436 inode->i_size = 0; 437 fat_truncate(inode); 438 } 439 clear_inode(inode); 440 } 441 442 static void fat_clear_inode(struct inode *inode) 443 { 444 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 445 446 if (is_bad_inode(inode)) 447 return; 448 lock_kernel(); 449 spin_lock(&sbi->inode_hash_lock); 450 fat_cache_inval_inode(inode); 451 hlist_del_init(&MSDOS_I(inode)->i_fat_hash); 452 spin_unlock(&sbi->inode_hash_lock); 453 unlock_kernel(); 454 } 455 456 static void fat_write_super(struct super_block *sb) 457 { 458 sb->s_dirt = 0; 459 460 if (!(sb->s_flags & MS_RDONLY)) 461 fat_clusters_flush(sb); 462 } 463 464 static void fat_put_super(struct super_block *sb) 465 { 466 struct msdos_sb_info *sbi = MSDOS_SB(sb); 467 468 if (sbi->nls_disk) { 469 unload_nls(sbi->nls_disk); 470 sbi->nls_disk = NULL; 471 sbi->options.codepage = fat_default_codepage; 472 } 473 if (sbi->nls_io) { 474 unload_nls(sbi->nls_io); 475 sbi->nls_io = NULL; 476 } 477 if (sbi->options.iocharset != fat_default_iocharset) { 478 kfree(sbi->options.iocharset); 479 sbi->options.iocharset = fat_default_iocharset; 480 } 481 482 sb->s_fs_info = NULL; 483 kfree(sbi); 484 } 485 486 static kmem_cache_t *fat_inode_cachep; 487 488 static struct inode *fat_alloc_inode(struct super_block *sb) 489 { 490 struct msdos_inode_info *ei; 491 ei = kmem_cache_alloc(fat_inode_cachep, SLAB_KERNEL); 492 if (!ei) 493 return NULL; 494 return &ei->vfs_inode; 495 } 496 497 static void fat_destroy_inode(struct inode *inode) 498 { 499 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode)); 500 } 501 502 static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags) 503 { 504 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo; 505 506 if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == 507 SLAB_CTOR_CONSTRUCTOR) { 508 spin_lock_init(&ei->cache_lru_lock); 509 ei->nr_caches = 0; 510 ei->cache_valid_id = FAT_CACHE_VALID + 1; 511 INIT_LIST_HEAD(&ei->cache_lru); 512 INIT_HLIST_NODE(&ei->i_fat_hash); 513 inode_init_once(&ei->vfs_inode); 514 } 515 } 516 517 static int __init fat_init_inodecache(void) 518 { 519 fat_inode_cachep = kmem_cache_create("fat_inode_cache", 520 sizeof(struct msdos_inode_info), 521 0, (SLAB_RECLAIM_ACCOUNT| 522 SLAB_MEM_SPREAD), 523 init_once, NULL); 524 if (fat_inode_cachep == NULL) 525 return -ENOMEM; 526 return 0; 527 } 528 529 static void __exit fat_destroy_inodecache(void) 530 { 531 if (kmem_cache_destroy(fat_inode_cachep)) 532 printk(KERN_INFO "fat_inode_cache: not all structures were freed\n"); 533 } 534 535 static int fat_remount(struct super_block *sb, int *flags, char *data) 536 { 537 struct msdos_sb_info *sbi = MSDOS_SB(sb); 538 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME); 539 return 0; 540 } 541 542 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf) 543 { 544 struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb); 545 546 /* If the count of free cluster is still unknown, counts it here. */ 547 if (sbi->free_clusters == -1) { 548 int err = fat_count_free_clusters(dentry->d_sb); 549 if (err) 550 return err; 551 } 552 553 buf->f_type = dentry->d_sb->s_magic; 554 buf->f_bsize = sbi->cluster_size; 555 buf->f_blocks = sbi->max_cluster - FAT_START_ENT; 556 buf->f_bfree = sbi->free_clusters; 557 buf->f_bavail = sbi->free_clusters; 558 buf->f_namelen = sbi->options.isvfat ? 260 : 12; 559 560 return 0; 561 } 562 563 static int fat_write_inode(struct inode *inode, int wait) 564 { 565 struct super_block *sb = inode->i_sb; 566 struct msdos_sb_info *sbi = MSDOS_SB(sb); 567 struct buffer_head *bh; 568 struct msdos_dir_entry *raw_entry; 569 loff_t i_pos; 570 int err = 0; 571 572 retry: 573 i_pos = MSDOS_I(inode)->i_pos; 574 if (inode->i_ino == MSDOS_ROOT_INO || !i_pos) 575 return 0; 576 577 lock_kernel(); 578 bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits); 579 if (!bh) { 580 printk(KERN_ERR "FAT: unable to read inode block " 581 "for updating (i_pos %lld)\n", i_pos); 582 err = -EIO; 583 goto out; 584 } 585 spin_lock(&sbi->inode_hash_lock); 586 if (i_pos != MSDOS_I(inode)->i_pos) { 587 spin_unlock(&sbi->inode_hash_lock); 588 brelse(bh); 589 unlock_kernel(); 590 goto retry; 591 } 592 593 raw_entry = &((struct msdos_dir_entry *) (bh->b_data)) 594 [i_pos & (sbi->dir_per_block - 1)]; 595 if (S_ISDIR(inode->i_mode)) 596 raw_entry->size = 0; 597 else 598 raw_entry->size = cpu_to_le32(inode->i_size); 599 raw_entry->attr = fat_attr(inode); 600 raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart); 601 raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16); 602 fat_date_unix2dos(inode->i_mtime.tv_sec, &raw_entry->time, &raw_entry->date); 603 if (sbi->options.isvfat) { 604 __le16 atime; 605 fat_date_unix2dos(inode->i_ctime.tv_sec,&raw_entry->ctime,&raw_entry->cdate); 606 fat_date_unix2dos(inode->i_atime.tv_sec,&atime,&raw_entry->adate); 607 raw_entry->ctime_cs = (inode->i_ctime.tv_sec & 1) * 100 + 608 inode->i_ctime.tv_nsec / 10000000; 609 } 610 spin_unlock(&sbi->inode_hash_lock); 611 mark_buffer_dirty(bh); 612 if (wait) 613 err = sync_dirty_buffer(bh); 614 brelse(bh); 615 out: 616 unlock_kernel(); 617 return err; 618 } 619 620 int fat_sync_inode(struct inode *inode) 621 { 622 return fat_write_inode(inode, 1); 623 } 624 625 EXPORT_SYMBOL_GPL(fat_sync_inode); 626 627 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt); 628 static struct super_operations fat_sops = { 629 .alloc_inode = fat_alloc_inode, 630 .destroy_inode = fat_destroy_inode, 631 .write_inode = fat_write_inode, 632 .delete_inode = fat_delete_inode, 633 .put_super = fat_put_super, 634 .write_super = fat_write_super, 635 .statfs = fat_statfs, 636 .clear_inode = fat_clear_inode, 637 .remount_fs = fat_remount, 638 639 .read_inode = make_bad_inode, 640 641 .show_options = fat_show_options, 642 }; 643 644 /* 645 * a FAT file handle with fhtype 3 is 646 * 0/ i_ino - for fast, reliable lookup if still in the cache 647 * 1/ i_generation - to see if i_ino is still valid 648 * bit 0 == 0 iff directory 649 * 2/ i_pos(8-39) - if ino has changed, but still in cache 650 * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos 651 * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc 652 * 653 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum 654 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits 655 * of i_logstart is used to store the directory entry offset. 656 */ 657 658 static struct dentry * 659 fat_decode_fh(struct super_block *sb, __u32 *fh, int len, int fhtype, 660 int (*acceptable)(void *context, struct dentry *de), 661 void *context) 662 { 663 if (fhtype != 3) 664 return ERR_PTR(-ESTALE); 665 if (len < 5) 666 return ERR_PTR(-ESTALE); 667 668 return sb->s_export_op->find_exported_dentry(sb, fh, NULL, acceptable, context); 669 } 670 671 static struct dentry *fat_get_dentry(struct super_block *sb, void *inump) 672 { 673 struct inode *inode = NULL; 674 struct dentry *result; 675 __u32 *fh = inump; 676 677 inode = iget(sb, fh[0]); 678 if (!inode || is_bad_inode(inode) || inode->i_generation != fh[1]) { 679 if (inode) 680 iput(inode); 681 inode = NULL; 682 } 683 if (!inode) { 684 loff_t i_pos; 685 int i_logstart = fh[3] & 0x0fffffff; 686 687 i_pos = (loff_t)fh[2] << 8; 688 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28); 689 690 /* try 2 - see if i_pos is in F-d-c 691 * require i_logstart to be the same 692 * Will fail if you truncate and then re-write 693 */ 694 695 inode = fat_iget(sb, i_pos); 696 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) { 697 iput(inode); 698 inode = NULL; 699 } 700 } 701 if (!inode) { 702 /* For now, do nothing 703 * What we could do is: 704 * follow the file starting at fh[4], and record 705 * the ".." entry, and the name of the fh[2] entry. 706 * The follow the ".." file finding the next step up. 707 * This way we build a path to the root of 708 * the tree. If this works, we lookup the path and so 709 * get this inode into the cache. 710 * Finally try the fat_iget lookup again 711 * If that fails, then weare totally out of luck 712 * But all that is for another day 713 */ 714 } 715 if (!inode) 716 return ERR_PTR(-ESTALE); 717 718 719 /* now to find a dentry. 720 * If possible, get a well-connected one 721 */ 722 result = d_alloc_anon(inode); 723 if (result == NULL) { 724 iput(inode); 725 return ERR_PTR(-ENOMEM); 726 } 727 result->d_op = sb->s_root->d_op; 728 return result; 729 } 730 731 static int 732 fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable) 733 { 734 int len = *lenp; 735 struct inode *inode = de->d_inode; 736 u32 ipos_h, ipos_m, ipos_l; 737 738 if (len < 5) 739 return 255; /* no room */ 740 741 ipos_h = MSDOS_I(inode)->i_pos >> 8; 742 ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24; 743 ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28; 744 *lenp = 5; 745 fh[0] = inode->i_ino; 746 fh[1] = inode->i_generation; 747 fh[2] = ipos_h; 748 fh[3] = ipos_m | MSDOS_I(inode)->i_logstart; 749 spin_lock(&de->d_lock); 750 fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart; 751 spin_unlock(&de->d_lock); 752 return 3; 753 } 754 755 static struct dentry *fat_get_parent(struct dentry *child) 756 { 757 struct buffer_head *bh; 758 struct msdos_dir_entry *de; 759 loff_t i_pos; 760 struct dentry *parent; 761 struct inode *inode; 762 int err; 763 764 lock_kernel(); 765 766 err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos); 767 if (err) { 768 parent = ERR_PTR(err); 769 goto out; 770 } 771 inode = fat_build_inode(child->d_sb, de, i_pos); 772 brelse(bh); 773 if (IS_ERR(inode)) { 774 parent = ERR_PTR(PTR_ERR(inode)); 775 goto out; 776 } 777 parent = d_alloc_anon(inode); 778 if (!parent) { 779 iput(inode); 780 parent = ERR_PTR(-ENOMEM); 781 } 782 out: 783 unlock_kernel(); 784 785 return parent; 786 } 787 788 static struct export_operations fat_export_ops = { 789 .decode_fh = fat_decode_fh, 790 .encode_fh = fat_encode_fh, 791 .get_dentry = fat_get_dentry, 792 .get_parent = fat_get_parent, 793 }; 794 795 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt) 796 { 797 struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb); 798 struct fat_mount_options *opts = &sbi->options; 799 int isvfat = opts->isvfat; 800 801 if (opts->fs_uid != 0) 802 seq_printf(m, ",uid=%u", opts->fs_uid); 803 if (opts->fs_gid != 0) 804 seq_printf(m, ",gid=%u", opts->fs_gid); 805 seq_printf(m, ",fmask=%04o", opts->fs_fmask); 806 seq_printf(m, ",dmask=%04o", opts->fs_dmask); 807 if (sbi->nls_disk) 808 seq_printf(m, ",codepage=%s", sbi->nls_disk->charset); 809 if (isvfat) { 810 if (sbi->nls_io) 811 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset); 812 813 switch (opts->shortname) { 814 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95: 815 seq_puts(m, ",shortname=win95"); 816 break; 817 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT: 818 seq_puts(m, ",shortname=winnt"); 819 break; 820 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95: 821 seq_puts(m, ",shortname=mixed"); 822 break; 823 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95: 824 /* seq_puts(m, ",shortname=lower"); */ 825 break; 826 default: 827 seq_puts(m, ",shortname=unknown"); 828 break; 829 } 830 } 831 if (opts->name_check != 'n') 832 seq_printf(m, ",check=%c", opts->name_check); 833 if (opts->quiet) 834 seq_puts(m, ",quiet"); 835 if (opts->showexec) 836 seq_puts(m, ",showexec"); 837 if (opts->sys_immutable) 838 seq_puts(m, ",sys_immutable"); 839 if (!isvfat) { 840 if (opts->dotsOK) 841 seq_puts(m, ",dotsOK=yes"); 842 if (opts->nocase) 843 seq_puts(m, ",nocase"); 844 } else { 845 if (opts->utf8) 846 seq_puts(m, ",utf8"); 847 if (opts->unicode_xlate) 848 seq_puts(m, ",uni_xlate"); 849 if (!opts->numtail) 850 seq_puts(m, ",nonumtail"); 851 } 852 853 return 0; 854 } 855 856 enum { 857 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid, 858 Opt_umask, Opt_dmask, Opt_fmask, Opt_codepage, Opt_nocase, 859 Opt_quiet, Opt_showexec, Opt_debug, Opt_immutable, 860 Opt_dots, Opt_nodots, 861 Opt_charset, Opt_shortname_lower, Opt_shortname_win95, 862 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes, 863 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes, 864 Opt_obsolate, Opt_err, 865 }; 866 867 static match_table_t fat_tokens = { 868 {Opt_check_r, "check=relaxed"}, 869 {Opt_check_s, "check=strict"}, 870 {Opt_check_n, "check=normal"}, 871 {Opt_check_r, "check=r"}, 872 {Opt_check_s, "check=s"}, 873 {Opt_check_n, "check=n"}, 874 {Opt_uid, "uid=%u"}, 875 {Opt_gid, "gid=%u"}, 876 {Opt_umask, "umask=%o"}, 877 {Opt_dmask, "dmask=%o"}, 878 {Opt_fmask, "fmask=%o"}, 879 {Opt_codepage, "codepage=%u"}, 880 {Opt_nocase, "nocase"}, 881 {Opt_quiet, "quiet"}, 882 {Opt_showexec, "showexec"}, 883 {Opt_debug, "debug"}, 884 {Opt_immutable, "sys_immutable"}, 885 {Opt_obsolate, "conv=binary"}, 886 {Opt_obsolate, "conv=text"}, 887 {Opt_obsolate, "conv=auto"}, 888 {Opt_obsolate, "conv=b"}, 889 {Opt_obsolate, "conv=t"}, 890 {Opt_obsolate, "conv=a"}, 891 {Opt_obsolate, "fat=%u"}, 892 {Opt_obsolate, "blocksize=%u"}, 893 {Opt_obsolate, "cvf_format=%20s"}, 894 {Opt_obsolate, "cvf_options=%100s"}, 895 {Opt_obsolate, "posix"}, 896 {Opt_err, NULL} 897 }; 898 static match_table_t msdos_tokens = { 899 {Opt_nodots, "nodots"}, 900 {Opt_nodots, "dotsOK=no"}, 901 {Opt_dots, "dots"}, 902 {Opt_dots, "dotsOK=yes"}, 903 {Opt_err, NULL} 904 }; 905 static match_table_t vfat_tokens = { 906 {Opt_charset, "iocharset=%s"}, 907 {Opt_shortname_lower, "shortname=lower"}, 908 {Opt_shortname_win95, "shortname=win95"}, 909 {Opt_shortname_winnt, "shortname=winnt"}, 910 {Opt_shortname_mixed, "shortname=mixed"}, 911 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */ 912 {Opt_utf8_no, "utf8=no"}, 913 {Opt_utf8_no, "utf8=false"}, 914 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */ 915 {Opt_utf8_yes, "utf8=yes"}, 916 {Opt_utf8_yes, "utf8=true"}, 917 {Opt_utf8_yes, "utf8"}, 918 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */ 919 {Opt_uni_xl_no, "uni_xlate=no"}, 920 {Opt_uni_xl_no, "uni_xlate=false"}, 921 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */ 922 {Opt_uni_xl_yes, "uni_xlate=yes"}, 923 {Opt_uni_xl_yes, "uni_xlate=true"}, 924 {Opt_uni_xl_yes, "uni_xlate"}, 925 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */ 926 {Opt_nonumtail_no, "nonumtail=no"}, 927 {Opt_nonumtail_no, "nonumtail=false"}, 928 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */ 929 {Opt_nonumtail_yes, "nonumtail=yes"}, 930 {Opt_nonumtail_yes, "nonumtail=true"}, 931 {Opt_nonumtail_yes, "nonumtail"}, 932 {Opt_err, NULL} 933 }; 934 935 static int parse_options(char *options, int is_vfat, int silent, int *debug, 936 struct fat_mount_options *opts) 937 { 938 char *p; 939 substring_t args[MAX_OPT_ARGS]; 940 int option; 941 char *iocharset; 942 943 opts->isvfat = is_vfat; 944 945 opts->fs_uid = current->uid; 946 opts->fs_gid = current->gid; 947 opts->fs_fmask = opts->fs_dmask = current->fs->umask; 948 opts->codepage = fat_default_codepage; 949 opts->iocharset = fat_default_iocharset; 950 if (is_vfat) 951 opts->shortname = VFAT_SFN_DISPLAY_LOWER|VFAT_SFN_CREATE_WIN95; 952 else 953 opts->shortname = 0; 954 opts->name_check = 'n'; 955 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0; 956 opts->utf8 = opts->unicode_xlate = 0; 957 opts->numtail = 1; 958 opts->nocase = 0; 959 *debug = 0; 960 961 if (!options) 962 return 0; 963 964 while ((p = strsep(&options, ",")) != NULL) { 965 int token; 966 if (!*p) 967 continue; 968 969 token = match_token(p, fat_tokens, args); 970 if (token == Opt_err) { 971 if (is_vfat) 972 token = match_token(p, vfat_tokens, args); 973 else 974 token = match_token(p, msdos_tokens, args); 975 } 976 switch (token) { 977 case Opt_check_s: 978 opts->name_check = 's'; 979 break; 980 case Opt_check_r: 981 opts->name_check = 'r'; 982 break; 983 case Opt_check_n: 984 opts->name_check = 'n'; 985 break; 986 case Opt_nocase: 987 if (!is_vfat) 988 opts->nocase = 1; 989 else { 990 /* for backward compatibility */ 991 opts->shortname = VFAT_SFN_DISPLAY_WIN95 992 | VFAT_SFN_CREATE_WIN95; 993 } 994 break; 995 case Opt_quiet: 996 opts->quiet = 1; 997 break; 998 case Opt_showexec: 999 opts->showexec = 1; 1000 break; 1001 case Opt_debug: 1002 *debug = 1; 1003 break; 1004 case Opt_immutable: 1005 opts->sys_immutable = 1; 1006 break; 1007 case Opt_uid: 1008 if (match_int(&args[0], &option)) 1009 return 0; 1010 opts->fs_uid = option; 1011 break; 1012 case Opt_gid: 1013 if (match_int(&args[0], &option)) 1014 return 0; 1015 opts->fs_gid = option; 1016 break; 1017 case Opt_umask: 1018 if (match_octal(&args[0], &option)) 1019 return 0; 1020 opts->fs_fmask = opts->fs_dmask = option; 1021 break; 1022 case Opt_dmask: 1023 if (match_octal(&args[0], &option)) 1024 return 0; 1025 opts->fs_dmask = option; 1026 break; 1027 case Opt_fmask: 1028 if (match_octal(&args[0], &option)) 1029 return 0; 1030 opts->fs_fmask = option; 1031 break; 1032 case Opt_codepage: 1033 if (match_int(&args[0], &option)) 1034 return 0; 1035 opts->codepage = option; 1036 break; 1037 1038 /* msdos specific */ 1039 case Opt_dots: 1040 opts->dotsOK = 1; 1041 break; 1042 case Opt_nodots: 1043 opts->dotsOK = 0; 1044 break; 1045 1046 /* vfat specific */ 1047 case Opt_charset: 1048 if (opts->iocharset != fat_default_iocharset) 1049 kfree(opts->iocharset); 1050 iocharset = match_strdup(&args[0]); 1051 if (!iocharset) 1052 return -ENOMEM; 1053 opts->iocharset = iocharset; 1054 break; 1055 case Opt_shortname_lower: 1056 opts->shortname = VFAT_SFN_DISPLAY_LOWER 1057 | VFAT_SFN_CREATE_WIN95; 1058 break; 1059 case Opt_shortname_win95: 1060 opts->shortname = VFAT_SFN_DISPLAY_WIN95 1061 | VFAT_SFN_CREATE_WIN95; 1062 break; 1063 case Opt_shortname_winnt: 1064 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1065 | VFAT_SFN_CREATE_WINNT; 1066 break; 1067 case Opt_shortname_mixed: 1068 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1069 | VFAT_SFN_CREATE_WIN95; 1070 break; 1071 case Opt_utf8_no: /* 0 or no or false */ 1072 opts->utf8 = 0; 1073 break; 1074 case Opt_utf8_yes: /* empty or 1 or yes or true */ 1075 opts->utf8 = 1; 1076 break; 1077 case Opt_uni_xl_no: /* 0 or no or false */ 1078 opts->unicode_xlate = 0; 1079 break; 1080 case Opt_uni_xl_yes: /* empty or 1 or yes or true */ 1081 opts->unicode_xlate = 1; 1082 break; 1083 case Opt_nonumtail_no: /* 0 or no or false */ 1084 opts->numtail = 1; /* negated option */ 1085 break; 1086 case Opt_nonumtail_yes: /* empty or 1 or yes or true */ 1087 opts->numtail = 0; /* negated option */ 1088 break; 1089 1090 /* obsolete mount options */ 1091 case Opt_obsolate: 1092 printk(KERN_INFO "FAT: \"%s\" option is obsolete, " 1093 "not supported now\n", p); 1094 break; 1095 /* unknown option */ 1096 default: 1097 if (!silent) { 1098 printk(KERN_ERR 1099 "FAT: Unrecognized mount option \"%s\" " 1100 "or missing value\n", p); 1101 } 1102 return -EINVAL; 1103 } 1104 } 1105 /* UTF-8 doesn't provide FAT semantics */ 1106 if (!strcmp(opts->iocharset, "utf8")) { 1107 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset" 1108 " for FAT filesystems, filesystem will be case sensitive!\n"); 1109 } 1110 1111 if (opts->unicode_xlate) 1112 opts->utf8 = 0; 1113 1114 return 0; 1115 } 1116 1117 static int fat_read_root(struct inode *inode) 1118 { 1119 struct super_block *sb = inode->i_sb; 1120 struct msdos_sb_info *sbi = MSDOS_SB(sb); 1121 int error; 1122 1123 MSDOS_I(inode)->i_pos = 0; 1124 inode->i_uid = sbi->options.fs_uid; 1125 inode->i_gid = sbi->options.fs_gid; 1126 inode->i_version++; 1127 inode->i_generation = 0; 1128 inode->i_mode = (S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR; 1129 inode->i_op = sbi->dir_ops; 1130 inode->i_fop = &fat_dir_operations; 1131 if (sbi->fat_bits == 32) { 1132 MSDOS_I(inode)->i_start = sbi->root_cluster; 1133 error = fat_calc_dir_size(inode); 1134 if (error < 0) 1135 return error; 1136 } else { 1137 MSDOS_I(inode)->i_start = 0; 1138 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry); 1139 } 1140 inode->i_blksize = sbi->cluster_size; 1141 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 1142 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 1143 MSDOS_I(inode)->i_logstart = 0; 1144 MSDOS_I(inode)->mmu_private = inode->i_size; 1145 1146 MSDOS_I(inode)->i_attrs = ATTR_NONE; 1147 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0; 1148 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0; 1149 inode->i_nlink = fat_subdirs(inode)+2; 1150 1151 return 0; 1152 } 1153 1154 /* 1155 * Read the super block of an MS-DOS FS. 1156 */ 1157 int fat_fill_super(struct super_block *sb, void *data, int silent, 1158 struct inode_operations *fs_dir_inode_ops, int isvfat) 1159 { 1160 struct inode *root_inode = NULL; 1161 struct buffer_head *bh; 1162 struct fat_boot_sector *b; 1163 struct msdos_sb_info *sbi; 1164 u16 logical_sector_size; 1165 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors; 1166 int debug; 1167 unsigned int media; 1168 long error; 1169 char buf[50]; 1170 1171 sbi = kmalloc(sizeof(struct msdos_sb_info), GFP_KERNEL); 1172 if (!sbi) 1173 return -ENOMEM; 1174 sb->s_fs_info = sbi; 1175 memset(sbi, 0, sizeof(struct msdos_sb_info)); 1176 1177 sb->s_flags |= MS_NODIRATIME; 1178 sb->s_magic = MSDOS_SUPER_MAGIC; 1179 sb->s_op = &fat_sops; 1180 sb->s_export_op = &fat_export_ops; 1181 sbi->dir_ops = fs_dir_inode_ops; 1182 1183 error = parse_options(data, isvfat, silent, &debug, &sbi->options); 1184 if (error) 1185 goto out_fail; 1186 1187 error = -EIO; 1188 sb_min_blocksize(sb, 512); 1189 bh = sb_bread(sb, 0); 1190 if (bh == NULL) { 1191 printk(KERN_ERR "FAT: unable to read boot sector\n"); 1192 goto out_fail; 1193 } 1194 1195 b = (struct fat_boot_sector *) bh->b_data; 1196 if (!b->reserved) { 1197 if (!silent) 1198 printk(KERN_ERR "FAT: bogus number of reserved sectors\n"); 1199 brelse(bh); 1200 goto out_invalid; 1201 } 1202 if (!b->fats) { 1203 if (!silent) 1204 printk(KERN_ERR "FAT: bogus number of FAT structure\n"); 1205 brelse(bh); 1206 goto out_invalid; 1207 } 1208 1209 /* 1210 * Earlier we checked here that b->secs_track and b->head are nonzero, 1211 * but it turns out valid FAT filesystems can have zero there. 1212 */ 1213 1214 media = b->media; 1215 if (!FAT_VALID_MEDIA(media)) { 1216 if (!silent) 1217 printk(KERN_ERR "FAT: invalid media value (0x%02x)\n", 1218 media); 1219 brelse(bh); 1220 goto out_invalid; 1221 } 1222 logical_sector_size = 1223 le16_to_cpu(get_unaligned((__le16 *)&b->sector_size)); 1224 if (!logical_sector_size 1225 || (logical_sector_size & (logical_sector_size - 1)) 1226 || (logical_sector_size < 512) 1227 || (PAGE_CACHE_SIZE < logical_sector_size)) { 1228 if (!silent) 1229 printk(KERN_ERR "FAT: bogus logical sector size %u\n", 1230 logical_sector_size); 1231 brelse(bh); 1232 goto out_invalid; 1233 } 1234 sbi->sec_per_clus = b->sec_per_clus; 1235 if (!sbi->sec_per_clus 1236 || (sbi->sec_per_clus & (sbi->sec_per_clus - 1))) { 1237 if (!silent) 1238 printk(KERN_ERR "FAT: bogus sectors per cluster %u\n", 1239 sbi->sec_per_clus); 1240 brelse(bh); 1241 goto out_invalid; 1242 } 1243 1244 if (logical_sector_size < sb->s_blocksize) { 1245 printk(KERN_ERR "FAT: logical sector size too small for device" 1246 " (logical sector size = %u)\n", logical_sector_size); 1247 brelse(bh); 1248 goto out_fail; 1249 } 1250 if (logical_sector_size > sb->s_blocksize) { 1251 brelse(bh); 1252 1253 if (!sb_set_blocksize(sb, logical_sector_size)) { 1254 printk(KERN_ERR "FAT: unable to set blocksize %u\n", 1255 logical_sector_size); 1256 goto out_fail; 1257 } 1258 bh = sb_bread(sb, 0); 1259 if (bh == NULL) { 1260 printk(KERN_ERR "FAT: unable to read boot sector" 1261 " (logical sector size = %lu)\n", 1262 sb->s_blocksize); 1263 goto out_fail; 1264 } 1265 b = (struct fat_boot_sector *) bh->b_data; 1266 } 1267 1268 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus; 1269 sbi->cluster_bits = ffs(sbi->cluster_size) - 1; 1270 sbi->fats = b->fats; 1271 sbi->fat_bits = 0; /* Don't know yet */ 1272 sbi->fat_start = le16_to_cpu(b->reserved); 1273 sbi->fat_length = le16_to_cpu(b->fat_length); 1274 sbi->root_cluster = 0; 1275 sbi->free_clusters = -1; /* Don't know yet */ 1276 sbi->prev_free = FAT_START_ENT; 1277 1278 if (!sbi->fat_length && b->fat32_length) { 1279 struct fat_boot_fsinfo *fsinfo; 1280 struct buffer_head *fsinfo_bh; 1281 1282 /* Must be FAT32 */ 1283 sbi->fat_bits = 32; 1284 sbi->fat_length = le32_to_cpu(b->fat32_length); 1285 sbi->root_cluster = le32_to_cpu(b->root_cluster); 1286 1287 sb->s_maxbytes = 0xffffffff; 1288 1289 /* MC - if info_sector is 0, don't multiply by 0 */ 1290 sbi->fsinfo_sector = le16_to_cpu(b->info_sector); 1291 if (sbi->fsinfo_sector == 0) 1292 sbi->fsinfo_sector = 1; 1293 1294 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector); 1295 if (fsinfo_bh == NULL) { 1296 printk(KERN_ERR "FAT: bread failed, FSINFO block" 1297 " (sector = %lu)\n", sbi->fsinfo_sector); 1298 brelse(bh); 1299 goto out_fail; 1300 } 1301 1302 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data; 1303 if (!IS_FSINFO(fsinfo)) { 1304 printk(KERN_WARNING 1305 "FAT: Did not find valid FSINFO signature.\n" 1306 " Found signature1 0x%08x signature2 0x%08x" 1307 " (sector = %lu)\n", 1308 le32_to_cpu(fsinfo->signature1), 1309 le32_to_cpu(fsinfo->signature2), 1310 sbi->fsinfo_sector); 1311 } else { 1312 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters); 1313 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster); 1314 } 1315 1316 brelse(fsinfo_bh); 1317 } 1318 1319 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry); 1320 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1; 1321 1322 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length; 1323 sbi->dir_entries = 1324 le16_to_cpu(get_unaligned((__le16 *)&b->dir_entries)); 1325 if (sbi->dir_entries & (sbi->dir_per_block - 1)) { 1326 if (!silent) 1327 printk(KERN_ERR "FAT: bogus directroy-entries per block" 1328 " (%u)\n", sbi->dir_entries); 1329 brelse(bh); 1330 goto out_invalid; 1331 } 1332 1333 rootdir_sectors = sbi->dir_entries 1334 * sizeof(struct msdos_dir_entry) / sb->s_blocksize; 1335 sbi->data_start = sbi->dir_start + rootdir_sectors; 1336 total_sectors = le16_to_cpu(get_unaligned((__le16 *)&b->sectors)); 1337 if (total_sectors == 0) 1338 total_sectors = le32_to_cpu(b->total_sect); 1339 1340 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus; 1341 1342 if (sbi->fat_bits != 32) 1343 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12; 1344 1345 /* check that FAT table does not overflow */ 1346 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits; 1347 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT); 1348 if (total_clusters > MAX_FAT(sb)) { 1349 if (!silent) 1350 printk(KERN_ERR "FAT: count of clusters too big (%u)\n", 1351 total_clusters); 1352 brelse(bh); 1353 goto out_invalid; 1354 } 1355 1356 sbi->max_cluster = total_clusters + FAT_START_ENT; 1357 /* check the free_clusters, it's not necessarily correct */ 1358 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters) 1359 sbi->free_clusters = -1; 1360 /* check the prev_free, it's not necessarily correct */ 1361 sbi->prev_free %= sbi->max_cluster; 1362 if (sbi->prev_free < FAT_START_ENT) 1363 sbi->prev_free = FAT_START_ENT; 1364 1365 brelse(bh); 1366 1367 /* set up enough so that it can read an inode */ 1368 fat_hash_init(sb); 1369 fat_ent_access_init(sb); 1370 1371 /* 1372 * The low byte of FAT's first entry must have same value with 1373 * media-field. But in real world, too many devices is 1374 * writing wrong value. So, removed that validity check. 1375 * 1376 * if (FAT_FIRST_ENT(sb, media) != first) 1377 */ 1378 1379 error = -EINVAL; 1380 sprintf(buf, "cp%d", sbi->options.codepage); 1381 sbi->nls_disk = load_nls(buf); 1382 if (!sbi->nls_disk) { 1383 printk(KERN_ERR "FAT: codepage %s not found\n", buf); 1384 goto out_fail; 1385 } 1386 1387 /* FIXME: utf8 is using iocharset for upper/lower conversion */ 1388 if (sbi->options.isvfat) { 1389 sbi->nls_io = load_nls(sbi->options.iocharset); 1390 if (!sbi->nls_io) { 1391 printk(KERN_ERR "FAT: IO charset %s not found\n", 1392 sbi->options.iocharset); 1393 goto out_fail; 1394 } 1395 } 1396 1397 error = -ENOMEM; 1398 root_inode = new_inode(sb); 1399 if (!root_inode) 1400 goto out_fail; 1401 root_inode->i_ino = MSDOS_ROOT_INO; 1402 root_inode->i_version = 1; 1403 error = fat_read_root(root_inode); 1404 if (error < 0) 1405 goto out_fail; 1406 error = -ENOMEM; 1407 insert_inode_hash(root_inode); 1408 sb->s_root = d_alloc_root(root_inode); 1409 if (!sb->s_root) { 1410 printk(KERN_ERR "FAT: get root inode failed\n"); 1411 goto out_fail; 1412 } 1413 1414 return 0; 1415 1416 out_invalid: 1417 error = -EINVAL; 1418 if (!silent) 1419 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem" 1420 " on dev %s.\n", sb->s_id); 1421 1422 out_fail: 1423 if (root_inode) 1424 iput(root_inode); 1425 if (sbi->nls_io) 1426 unload_nls(sbi->nls_io); 1427 if (sbi->nls_disk) 1428 unload_nls(sbi->nls_disk); 1429 if (sbi->options.iocharset != fat_default_iocharset) 1430 kfree(sbi->options.iocharset); 1431 sb->s_fs_info = NULL; 1432 kfree(sbi); 1433 return error; 1434 } 1435 1436 EXPORT_SYMBOL_GPL(fat_fill_super); 1437 1438 static int __init init_fat_fs(void) 1439 { 1440 int err; 1441 1442 err = fat_cache_init(); 1443 if (err) 1444 return err; 1445 1446 err = fat_init_inodecache(); 1447 if (err) 1448 goto failed; 1449 1450 return 0; 1451 1452 failed: 1453 fat_cache_destroy(); 1454 return err; 1455 } 1456 1457 static void __exit exit_fat_fs(void) 1458 { 1459 fat_cache_destroy(); 1460 fat_destroy_inodecache(); 1461 } 1462 1463 module_init(init_fat_fs) 1464 module_exit(exit_fat_fs) 1465 1466 MODULE_LICENSE("GPL"); 1467