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 unsigned long max_blocks, 105 struct buffer_head *bh_result, int create) 106 { 107 struct super_block *sb = inode->i_sb; 108 int err; 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 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 init_once, NULL); 523 if (fat_inode_cachep == NULL) 524 return -ENOMEM; 525 return 0; 526 } 527 528 static void __exit fat_destroy_inodecache(void) 529 { 530 if (kmem_cache_destroy(fat_inode_cachep)) 531 printk(KERN_INFO "fat_inode_cache: not all structures were freed\n"); 532 } 533 534 static int fat_remount(struct super_block *sb, int *flags, char *data) 535 { 536 struct msdos_sb_info *sbi = MSDOS_SB(sb); 537 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME); 538 return 0; 539 } 540 541 static int fat_statfs(struct super_block *sb, struct kstatfs *buf) 542 { 543 struct msdos_sb_info *sbi = MSDOS_SB(sb); 544 545 /* If the count of free cluster is still unknown, counts it here. */ 546 if (sbi->free_clusters == -1) { 547 int err = fat_count_free_clusters(sb); 548 if (err) 549 return err; 550 } 551 552 buf->f_type = sb->s_magic; 553 buf->f_bsize = sbi->cluster_size; 554 buf->f_blocks = sbi->max_cluster - FAT_START_ENT; 555 buf->f_bfree = sbi->free_clusters; 556 buf->f_bavail = sbi->free_clusters; 557 buf->f_namelen = sbi->options.isvfat ? 260 : 12; 558 559 return 0; 560 } 561 562 static int fat_write_inode(struct inode *inode, int wait) 563 { 564 struct super_block *sb = inode->i_sb; 565 struct msdos_sb_info *sbi = MSDOS_SB(sb); 566 struct buffer_head *bh; 567 struct msdos_dir_entry *raw_entry; 568 loff_t i_pos; 569 int err = 0; 570 571 retry: 572 i_pos = MSDOS_I(inode)->i_pos; 573 if (inode->i_ino == MSDOS_ROOT_INO || !i_pos) 574 return 0; 575 576 lock_kernel(); 577 bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits); 578 if (!bh) { 579 printk(KERN_ERR "FAT: unable to read inode block " 580 "for updating (i_pos %lld)\n", i_pos); 581 err = -EIO; 582 goto out; 583 } 584 spin_lock(&sbi->inode_hash_lock); 585 if (i_pos != MSDOS_I(inode)->i_pos) { 586 spin_unlock(&sbi->inode_hash_lock); 587 brelse(bh); 588 unlock_kernel(); 589 goto retry; 590 } 591 592 raw_entry = &((struct msdos_dir_entry *) (bh->b_data)) 593 [i_pos & (sbi->dir_per_block - 1)]; 594 if (S_ISDIR(inode->i_mode)) 595 raw_entry->size = 0; 596 else 597 raw_entry->size = cpu_to_le32(inode->i_size); 598 raw_entry->attr = fat_attr(inode); 599 raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart); 600 raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16); 601 fat_date_unix2dos(inode->i_mtime.tv_sec, &raw_entry->time, &raw_entry->date); 602 if (sbi->options.isvfat) { 603 __le16 atime; 604 fat_date_unix2dos(inode->i_ctime.tv_sec,&raw_entry->ctime,&raw_entry->cdate); 605 fat_date_unix2dos(inode->i_atime.tv_sec,&atime,&raw_entry->adate); 606 raw_entry->ctime_cs = (inode->i_ctime.tv_sec & 1) * 100 + 607 inode->i_ctime.tv_nsec / 10000000; 608 } 609 spin_unlock(&sbi->inode_hash_lock); 610 mark_buffer_dirty(bh); 611 if (wait) 612 err = sync_dirty_buffer(bh); 613 brelse(bh); 614 out: 615 unlock_kernel(); 616 return err; 617 } 618 619 int fat_sync_inode(struct inode *inode) 620 { 621 return fat_write_inode(inode, 1); 622 } 623 624 EXPORT_SYMBOL_GPL(fat_sync_inode); 625 626 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt); 627 static struct super_operations fat_sops = { 628 .alloc_inode = fat_alloc_inode, 629 .destroy_inode = fat_destroy_inode, 630 .write_inode = fat_write_inode, 631 .delete_inode = fat_delete_inode, 632 .put_super = fat_put_super, 633 .write_super = fat_write_super, 634 .statfs = fat_statfs, 635 .clear_inode = fat_clear_inode, 636 .remount_fs = fat_remount, 637 638 .read_inode = make_bad_inode, 639 640 .show_options = fat_show_options, 641 }; 642 643 /* 644 * a FAT file handle with fhtype 3 is 645 * 0/ i_ino - for fast, reliable lookup if still in the cache 646 * 1/ i_generation - to see if i_ino is still valid 647 * bit 0 == 0 iff directory 648 * 2/ i_pos(8-39) - if ino has changed, but still in cache 649 * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos 650 * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc 651 * 652 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum 653 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits 654 * of i_logstart is used to store the directory entry offset. 655 */ 656 657 static struct dentry * 658 fat_decode_fh(struct super_block *sb, __u32 *fh, int len, int fhtype, 659 int (*acceptable)(void *context, struct dentry *de), 660 void *context) 661 { 662 if (fhtype != 3) 663 return ERR_PTR(-ESTALE); 664 if (len < 5) 665 return ERR_PTR(-ESTALE); 666 667 return sb->s_export_op->find_exported_dentry(sb, fh, NULL, acceptable, context); 668 } 669 670 static struct dentry *fat_get_dentry(struct super_block *sb, void *inump) 671 { 672 struct inode *inode = NULL; 673 struct dentry *result; 674 __u32 *fh = inump; 675 676 inode = iget(sb, fh[0]); 677 if (!inode || is_bad_inode(inode) || inode->i_generation != fh[1]) { 678 if (inode) 679 iput(inode); 680 inode = NULL; 681 } 682 if (!inode) { 683 loff_t i_pos; 684 int i_logstart = fh[3] & 0x0fffffff; 685 686 i_pos = (loff_t)fh[2] << 8; 687 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28); 688 689 /* try 2 - see if i_pos is in F-d-c 690 * require i_logstart to be the same 691 * Will fail if you truncate and then re-write 692 */ 693 694 inode = fat_iget(sb, i_pos); 695 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) { 696 iput(inode); 697 inode = NULL; 698 } 699 } 700 if (!inode) { 701 /* For now, do nothing 702 * What we could do is: 703 * follow the file starting at fh[4], and record 704 * the ".." entry, and the name of the fh[2] entry. 705 * The follow the ".." file finding the next step up. 706 * This way we build a path to the root of 707 * the tree. If this works, we lookup the path and so 708 * get this inode into the cache. 709 * Finally try the fat_iget lookup again 710 * If that fails, then weare totally out of luck 711 * But all that is for another day 712 */ 713 } 714 if (!inode) 715 return ERR_PTR(-ESTALE); 716 717 718 /* now to find a dentry. 719 * If possible, get a well-connected one 720 */ 721 result = d_alloc_anon(inode); 722 if (result == NULL) { 723 iput(inode); 724 return ERR_PTR(-ENOMEM); 725 } 726 result->d_op = sb->s_root->d_op; 727 return result; 728 } 729 730 static int 731 fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable) 732 { 733 int len = *lenp; 734 struct inode *inode = de->d_inode; 735 u32 ipos_h, ipos_m, ipos_l; 736 737 if (len < 5) 738 return 255; /* no room */ 739 740 ipos_h = MSDOS_I(inode)->i_pos >> 8; 741 ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24; 742 ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28; 743 *lenp = 5; 744 fh[0] = inode->i_ino; 745 fh[1] = inode->i_generation; 746 fh[2] = ipos_h; 747 fh[3] = ipos_m | MSDOS_I(inode)->i_logstart; 748 spin_lock(&de->d_lock); 749 fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart; 750 spin_unlock(&de->d_lock); 751 return 3; 752 } 753 754 static struct dentry *fat_get_parent(struct dentry *child) 755 { 756 struct buffer_head *bh; 757 struct msdos_dir_entry *de; 758 loff_t i_pos; 759 struct dentry *parent; 760 struct inode *inode; 761 int err; 762 763 lock_kernel(); 764 765 err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos); 766 if (err) { 767 parent = ERR_PTR(err); 768 goto out; 769 } 770 inode = fat_build_inode(child->d_sb, de, i_pos); 771 brelse(bh); 772 if (IS_ERR(inode)) { 773 parent = ERR_PTR(PTR_ERR(inode)); 774 goto out; 775 } 776 parent = d_alloc_anon(inode); 777 if (!parent) { 778 iput(inode); 779 parent = ERR_PTR(-ENOMEM); 780 } 781 out: 782 unlock_kernel(); 783 784 return parent; 785 } 786 787 static struct export_operations fat_export_ops = { 788 .decode_fh = fat_decode_fh, 789 .encode_fh = fat_encode_fh, 790 .get_dentry = fat_get_dentry, 791 .get_parent = fat_get_parent, 792 }; 793 794 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt) 795 { 796 struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb); 797 struct fat_mount_options *opts = &sbi->options; 798 int isvfat = opts->isvfat; 799 800 if (opts->fs_uid != 0) 801 seq_printf(m, ",uid=%u", opts->fs_uid); 802 if (opts->fs_gid != 0) 803 seq_printf(m, ",gid=%u", opts->fs_gid); 804 seq_printf(m, ",fmask=%04o", opts->fs_fmask); 805 seq_printf(m, ",dmask=%04o", opts->fs_dmask); 806 if (sbi->nls_disk) 807 seq_printf(m, ",codepage=%s", sbi->nls_disk->charset); 808 if (isvfat) { 809 if (sbi->nls_io) 810 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset); 811 812 switch (opts->shortname) { 813 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95: 814 seq_puts(m, ",shortname=win95"); 815 break; 816 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT: 817 seq_puts(m, ",shortname=winnt"); 818 break; 819 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95: 820 seq_puts(m, ",shortname=mixed"); 821 break; 822 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95: 823 /* seq_puts(m, ",shortname=lower"); */ 824 break; 825 default: 826 seq_puts(m, ",shortname=unknown"); 827 break; 828 } 829 } 830 if (opts->name_check != 'n') 831 seq_printf(m, ",check=%c", opts->name_check); 832 if (opts->quiet) 833 seq_puts(m, ",quiet"); 834 if (opts->showexec) 835 seq_puts(m, ",showexec"); 836 if (opts->sys_immutable) 837 seq_puts(m, ",sys_immutable"); 838 if (!isvfat) { 839 if (opts->dotsOK) 840 seq_puts(m, ",dotsOK=yes"); 841 if (opts->nocase) 842 seq_puts(m, ",nocase"); 843 } else { 844 if (opts->utf8) 845 seq_puts(m, ",utf8"); 846 if (opts->unicode_xlate) 847 seq_puts(m, ",uni_xlate"); 848 if (!opts->numtail) 849 seq_puts(m, ",nonumtail"); 850 } 851 852 return 0; 853 } 854 855 enum { 856 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid, 857 Opt_umask, Opt_dmask, Opt_fmask, Opt_codepage, Opt_nocase, 858 Opt_quiet, Opt_showexec, Opt_debug, Opt_immutable, 859 Opt_dots, Opt_nodots, 860 Opt_charset, Opt_shortname_lower, Opt_shortname_win95, 861 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes, 862 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes, 863 Opt_obsolate, Opt_err, 864 }; 865 866 static match_table_t fat_tokens = { 867 {Opt_check_r, "check=relaxed"}, 868 {Opt_check_s, "check=strict"}, 869 {Opt_check_n, "check=normal"}, 870 {Opt_check_r, "check=r"}, 871 {Opt_check_s, "check=s"}, 872 {Opt_check_n, "check=n"}, 873 {Opt_uid, "uid=%u"}, 874 {Opt_gid, "gid=%u"}, 875 {Opt_umask, "umask=%o"}, 876 {Opt_dmask, "dmask=%o"}, 877 {Opt_fmask, "fmask=%o"}, 878 {Opt_codepage, "codepage=%u"}, 879 {Opt_nocase, "nocase"}, 880 {Opt_quiet, "quiet"}, 881 {Opt_showexec, "showexec"}, 882 {Opt_debug, "debug"}, 883 {Opt_immutable, "sys_immutable"}, 884 {Opt_obsolate, "conv=binary"}, 885 {Opt_obsolate, "conv=text"}, 886 {Opt_obsolate, "conv=auto"}, 887 {Opt_obsolate, "conv=b"}, 888 {Opt_obsolate, "conv=t"}, 889 {Opt_obsolate, "conv=a"}, 890 {Opt_obsolate, "fat=%u"}, 891 {Opt_obsolate, "blocksize=%u"}, 892 {Opt_obsolate, "cvf_format=%20s"}, 893 {Opt_obsolate, "cvf_options=%100s"}, 894 {Opt_obsolate, "posix"}, 895 {Opt_err, NULL} 896 }; 897 static match_table_t msdos_tokens = { 898 {Opt_nodots, "nodots"}, 899 {Opt_nodots, "dotsOK=no"}, 900 {Opt_dots, "dots"}, 901 {Opt_dots, "dotsOK=yes"}, 902 {Opt_err, NULL} 903 }; 904 static match_table_t vfat_tokens = { 905 {Opt_charset, "iocharset=%s"}, 906 {Opt_shortname_lower, "shortname=lower"}, 907 {Opt_shortname_win95, "shortname=win95"}, 908 {Opt_shortname_winnt, "shortname=winnt"}, 909 {Opt_shortname_mixed, "shortname=mixed"}, 910 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */ 911 {Opt_utf8_no, "utf8=no"}, 912 {Opt_utf8_no, "utf8=false"}, 913 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */ 914 {Opt_utf8_yes, "utf8=yes"}, 915 {Opt_utf8_yes, "utf8=true"}, 916 {Opt_utf8_yes, "utf8"}, 917 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */ 918 {Opt_uni_xl_no, "uni_xlate=no"}, 919 {Opt_uni_xl_no, "uni_xlate=false"}, 920 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */ 921 {Opt_uni_xl_yes, "uni_xlate=yes"}, 922 {Opt_uni_xl_yes, "uni_xlate=true"}, 923 {Opt_uni_xl_yes, "uni_xlate"}, 924 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */ 925 {Opt_nonumtail_no, "nonumtail=no"}, 926 {Opt_nonumtail_no, "nonumtail=false"}, 927 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */ 928 {Opt_nonumtail_yes, "nonumtail=yes"}, 929 {Opt_nonumtail_yes, "nonumtail=true"}, 930 {Opt_nonumtail_yes, "nonumtail"}, 931 {Opt_err, NULL} 932 }; 933 934 static int parse_options(char *options, int is_vfat, int silent, int *debug, 935 struct fat_mount_options *opts) 936 { 937 char *p; 938 substring_t args[MAX_OPT_ARGS]; 939 int option; 940 char *iocharset; 941 942 opts->isvfat = is_vfat; 943 944 opts->fs_uid = current->uid; 945 opts->fs_gid = current->gid; 946 opts->fs_fmask = opts->fs_dmask = current->fs->umask; 947 opts->codepage = fat_default_codepage; 948 opts->iocharset = fat_default_iocharset; 949 if (is_vfat) 950 opts->shortname = VFAT_SFN_DISPLAY_LOWER|VFAT_SFN_CREATE_WIN95; 951 else 952 opts->shortname = 0; 953 opts->name_check = 'n'; 954 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0; 955 opts->utf8 = opts->unicode_xlate = 0; 956 opts->numtail = 1; 957 opts->nocase = 0; 958 *debug = 0; 959 960 if (!options) 961 return 0; 962 963 while ((p = strsep(&options, ",")) != NULL) { 964 int token; 965 if (!*p) 966 continue; 967 968 token = match_token(p, fat_tokens, args); 969 if (token == Opt_err) { 970 if (is_vfat) 971 token = match_token(p, vfat_tokens, args); 972 else 973 token = match_token(p, msdos_tokens, args); 974 } 975 switch (token) { 976 case Opt_check_s: 977 opts->name_check = 's'; 978 break; 979 case Opt_check_r: 980 opts->name_check = 'r'; 981 break; 982 case Opt_check_n: 983 opts->name_check = 'n'; 984 break; 985 case Opt_nocase: 986 if (!is_vfat) 987 opts->nocase = 1; 988 else { 989 /* for backward compatibility */ 990 opts->shortname = VFAT_SFN_DISPLAY_WIN95 991 | VFAT_SFN_CREATE_WIN95; 992 } 993 break; 994 case Opt_quiet: 995 opts->quiet = 1; 996 break; 997 case Opt_showexec: 998 opts->showexec = 1; 999 break; 1000 case Opt_debug: 1001 *debug = 1; 1002 break; 1003 case Opt_immutable: 1004 opts->sys_immutable = 1; 1005 break; 1006 case Opt_uid: 1007 if (match_int(&args[0], &option)) 1008 return 0; 1009 opts->fs_uid = option; 1010 break; 1011 case Opt_gid: 1012 if (match_int(&args[0], &option)) 1013 return 0; 1014 opts->fs_gid = option; 1015 break; 1016 case Opt_umask: 1017 if (match_octal(&args[0], &option)) 1018 return 0; 1019 opts->fs_fmask = opts->fs_dmask = option; 1020 break; 1021 case Opt_dmask: 1022 if (match_octal(&args[0], &option)) 1023 return 0; 1024 opts->fs_dmask = option; 1025 break; 1026 case Opt_fmask: 1027 if (match_octal(&args[0], &option)) 1028 return 0; 1029 opts->fs_fmask = option; 1030 break; 1031 case Opt_codepage: 1032 if (match_int(&args[0], &option)) 1033 return 0; 1034 opts->codepage = option; 1035 break; 1036 1037 /* msdos specific */ 1038 case Opt_dots: 1039 opts->dotsOK = 1; 1040 break; 1041 case Opt_nodots: 1042 opts->dotsOK = 0; 1043 break; 1044 1045 /* vfat specific */ 1046 case Opt_charset: 1047 if (opts->iocharset != fat_default_iocharset) 1048 kfree(opts->iocharset); 1049 iocharset = match_strdup(&args[0]); 1050 if (!iocharset) 1051 return -ENOMEM; 1052 opts->iocharset = iocharset; 1053 break; 1054 case Opt_shortname_lower: 1055 opts->shortname = VFAT_SFN_DISPLAY_LOWER 1056 | VFAT_SFN_CREATE_WIN95; 1057 break; 1058 case Opt_shortname_win95: 1059 opts->shortname = VFAT_SFN_DISPLAY_WIN95 1060 | VFAT_SFN_CREATE_WIN95; 1061 break; 1062 case Opt_shortname_winnt: 1063 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1064 | VFAT_SFN_CREATE_WINNT; 1065 break; 1066 case Opt_shortname_mixed: 1067 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1068 | VFAT_SFN_CREATE_WIN95; 1069 break; 1070 case Opt_utf8_no: /* 0 or no or false */ 1071 opts->utf8 = 0; 1072 break; 1073 case Opt_utf8_yes: /* empty or 1 or yes or true */ 1074 opts->utf8 = 1; 1075 break; 1076 case Opt_uni_xl_no: /* 0 or no or false */ 1077 opts->unicode_xlate = 0; 1078 break; 1079 case Opt_uni_xl_yes: /* empty or 1 or yes or true */ 1080 opts->unicode_xlate = 1; 1081 break; 1082 case Opt_nonumtail_no: /* 0 or no or false */ 1083 opts->numtail = 1; /* negated option */ 1084 break; 1085 case Opt_nonumtail_yes: /* empty or 1 or yes or true */ 1086 opts->numtail = 0; /* negated option */ 1087 break; 1088 1089 /* obsolete mount options */ 1090 case Opt_obsolate: 1091 printk(KERN_INFO "FAT: \"%s\" option is obsolete, " 1092 "not supported now\n", p); 1093 break; 1094 /* unknown option */ 1095 default: 1096 if (!silent) { 1097 printk(KERN_ERR 1098 "FAT: Unrecognized mount option \"%s\" " 1099 "or missing value\n", p); 1100 } 1101 return -EINVAL; 1102 } 1103 } 1104 /* UTF-8 doesn't provide FAT semantics */ 1105 if (!strcmp(opts->iocharset, "utf8")) { 1106 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset" 1107 " for FAT filesystems, filesystem will be case sensitive!\n"); 1108 } 1109 1110 if (opts->unicode_xlate) 1111 opts->utf8 = 0; 1112 1113 return 0; 1114 } 1115 1116 static int fat_read_root(struct inode *inode) 1117 { 1118 struct super_block *sb = inode->i_sb; 1119 struct msdos_sb_info *sbi = MSDOS_SB(sb); 1120 int error; 1121 1122 MSDOS_I(inode)->i_pos = 0; 1123 inode->i_uid = sbi->options.fs_uid; 1124 inode->i_gid = sbi->options.fs_gid; 1125 inode->i_version++; 1126 inode->i_generation = 0; 1127 inode->i_mode = (S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR; 1128 inode->i_op = sbi->dir_ops; 1129 inode->i_fop = &fat_dir_operations; 1130 if (sbi->fat_bits == 32) { 1131 MSDOS_I(inode)->i_start = sbi->root_cluster; 1132 error = fat_calc_dir_size(inode); 1133 if (error < 0) 1134 return error; 1135 } else { 1136 MSDOS_I(inode)->i_start = 0; 1137 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry); 1138 } 1139 inode->i_blksize = sbi->cluster_size; 1140 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 1141 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 1142 MSDOS_I(inode)->i_logstart = 0; 1143 MSDOS_I(inode)->mmu_private = inode->i_size; 1144 1145 MSDOS_I(inode)->i_attrs = ATTR_NONE; 1146 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0; 1147 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0; 1148 inode->i_nlink = fat_subdirs(inode)+2; 1149 1150 return 0; 1151 } 1152 1153 /* 1154 * Read the super block of an MS-DOS FS. 1155 */ 1156 int fat_fill_super(struct super_block *sb, void *data, int silent, 1157 struct inode_operations *fs_dir_inode_ops, int isvfat) 1158 { 1159 struct inode *root_inode = NULL; 1160 struct buffer_head *bh; 1161 struct fat_boot_sector *b; 1162 struct msdos_sb_info *sbi; 1163 u16 logical_sector_size; 1164 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors; 1165 int debug; 1166 unsigned int media; 1167 long error; 1168 char buf[50]; 1169 1170 sbi = kmalloc(sizeof(struct msdos_sb_info), GFP_KERNEL); 1171 if (!sbi) 1172 return -ENOMEM; 1173 sb->s_fs_info = sbi; 1174 memset(sbi, 0, sizeof(struct msdos_sb_info)); 1175 1176 sb->s_flags |= MS_NODIRATIME; 1177 sb->s_magic = MSDOS_SUPER_MAGIC; 1178 sb->s_op = &fat_sops; 1179 sb->s_export_op = &fat_export_ops; 1180 sbi->dir_ops = fs_dir_inode_ops; 1181 1182 error = parse_options(data, isvfat, silent, &debug, &sbi->options); 1183 if (error) 1184 goto out_fail; 1185 1186 error = -EIO; 1187 sb_min_blocksize(sb, 512); 1188 bh = sb_bread(sb, 0); 1189 if (bh == NULL) { 1190 printk(KERN_ERR "FAT: unable to read boot sector\n"); 1191 goto out_fail; 1192 } 1193 1194 b = (struct fat_boot_sector *) bh->b_data; 1195 if (!b->reserved) { 1196 if (!silent) 1197 printk(KERN_ERR "FAT: bogus number of reserved sectors\n"); 1198 brelse(bh); 1199 goto out_invalid; 1200 } 1201 if (!b->fats) { 1202 if (!silent) 1203 printk(KERN_ERR "FAT: bogus number of FAT structure\n"); 1204 brelse(bh); 1205 goto out_invalid; 1206 } 1207 1208 /* 1209 * Earlier we checked here that b->secs_track and b->head are nonzero, 1210 * but it turns out valid FAT filesystems can have zero there. 1211 */ 1212 1213 media = b->media; 1214 if (!FAT_VALID_MEDIA(media)) { 1215 if (!silent) 1216 printk(KERN_ERR "FAT: invalid media value (0x%02x)\n", 1217 media); 1218 brelse(bh); 1219 goto out_invalid; 1220 } 1221 logical_sector_size = 1222 le16_to_cpu(get_unaligned((__le16 *)&b->sector_size)); 1223 if (!logical_sector_size 1224 || (logical_sector_size & (logical_sector_size - 1)) 1225 || (logical_sector_size < 512) 1226 || (PAGE_CACHE_SIZE < logical_sector_size)) { 1227 if (!silent) 1228 printk(KERN_ERR "FAT: bogus logical sector size %u\n", 1229 logical_sector_size); 1230 brelse(bh); 1231 goto out_invalid; 1232 } 1233 sbi->sec_per_clus = b->sec_per_clus; 1234 if (!sbi->sec_per_clus 1235 || (sbi->sec_per_clus & (sbi->sec_per_clus - 1))) { 1236 if (!silent) 1237 printk(KERN_ERR "FAT: bogus sectors per cluster %u\n", 1238 sbi->sec_per_clus); 1239 brelse(bh); 1240 goto out_invalid; 1241 } 1242 1243 if (logical_sector_size < sb->s_blocksize) { 1244 printk(KERN_ERR "FAT: logical sector size too small for device" 1245 " (logical sector size = %u)\n", logical_sector_size); 1246 brelse(bh); 1247 goto out_fail; 1248 } 1249 if (logical_sector_size > sb->s_blocksize) { 1250 brelse(bh); 1251 1252 if (!sb_set_blocksize(sb, logical_sector_size)) { 1253 printk(KERN_ERR "FAT: unable to set blocksize %u\n", 1254 logical_sector_size); 1255 goto out_fail; 1256 } 1257 bh = sb_bread(sb, 0); 1258 if (bh == NULL) { 1259 printk(KERN_ERR "FAT: unable to read boot sector" 1260 " (logical sector size = %lu)\n", 1261 sb->s_blocksize); 1262 goto out_fail; 1263 } 1264 b = (struct fat_boot_sector *) bh->b_data; 1265 } 1266 1267 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus; 1268 sbi->cluster_bits = ffs(sbi->cluster_size) - 1; 1269 sbi->fats = b->fats; 1270 sbi->fat_bits = 0; /* Don't know yet */ 1271 sbi->fat_start = le16_to_cpu(b->reserved); 1272 sbi->fat_length = le16_to_cpu(b->fat_length); 1273 sbi->root_cluster = 0; 1274 sbi->free_clusters = -1; /* Don't know yet */ 1275 sbi->prev_free = FAT_START_ENT; 1276 1277 if (!sbi->fat_length && b->fat32_length) { 1278 struct fat_boot_fsinfo *fsinfo; 1279 struct buffer_head *fsinfo_bh; 1280 1281 /* Must be FAT32 */ 1282 sbi->fat_bits = 32; 1283 sbi->fat_length = le32_to_cpu(b->fat32_length); 1284 sbi->root_cluster = le32_to_cpu(b->root_cluster); 1285 1286 sb->s_maxbytes = 0xffffffff; 1287 1288 /* MC - if info_sector is 0, don't multiply by 0 */ 1289 sbi->fsinfo_sector = le16_to_cpu(b->info_sector); 1290 if (sbi->fsinfo_sector == 0) 1291 sbi->fsinfo_sector = 1; 1292 1293 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector); 1294 if (fsinfo_bh == NULL) { 1295 printk(KERN_ERR "FAT: bread failed, FSINFO block" 1296 " (sector = %lu)\n", sbi->fsinfo_sector); 1297 brelse(bh); 1298 goto out_fail; 1299 } 1300 1301 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data; 1302 if (!IS_FSINFO(fsinfo)) { 1303 printk(KERN_WARNING 1304 "FAT: Did not find valid FSINFO signature.\n" 1305 " Found signature1 0x%08x signature2 0x%08x" 1306 " (sector = %lu)\n", 1307 le32_to_cpu(fsinfo->signature1), 1308 le32_to_cpu(fsinfo->signature2), 1309 sbi->fsinfo_sector); 1310 } else { 1311 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters); 1312 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster); 1313 } 1314 1315 brelse(fsinfo_bh); 1316 } 1317 1318 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry); 1319 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1; 1320 1321 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length; 1322 sbi->dir_entries = 1323 le16_to_cpu(get_unaligned((__le16 *)&b->dir_entries)); 1324 if (sbi->dir_entries & (sbi->dir_per_block - 1)) { 1325 if (!silent) 1326 printk(KERN_ERR "FAT: bogus directroy-entries per block" 1327 " (%u)\n", sbi->dir_entries); 1328 brelse(bh); 1329 goto out_invalid; 1330 } 1331 1332 rootdir_sectors = sbi->dir_entries 1333 * sizeof(struct msdos_dir_entry) / sb->s_blocksize; 1334 sbi->data_start = sbi->dir_start + rootdir_sectors; 1335 total_sectors = le16_to_cpu(get_unaligned((__le16 *)&b->sectors)); 1336 if (total_sectors == 0) 1337 total_sectors = le32_to_cpu(b->total_sect); 1338 1339 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus; 1340 1341 if (sbi->fat_bits != 32) 1342 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12; 1343 1344 /* check that FAT table does not overflow */ 1345 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits; 1346 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT); 1347 if (total_clusters > MAX_FAT(sb)) { 1348 if (!silent) 1349 printk(KERN_ERR "FAT: count of clusters too big (%u)\n", 1350 total_clusters); 1351 brelse(bh); 1352 goto out_invalid; 1353 } 1354 1355 sbi->max_cluster = total_clusters + FAT_START_ENT; 1356 /* check the free_clusters, it's not necessarily correct */ 1357 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters) 1358 sbi->free_clusters = -1; 1359 /* check the prev_free, it's not necessarily correct */ 1360 sbi->prev_free %= sbi->max_cluster; 1361 if (sbi->prev_free < FAT_START_ENT) 1362 sbi->prev_free = FAT_START_ENT; 1363 1364 brelse(bh); 1365 1366 /* set up enough so that it can read an inode */ 1367 fat_hash_init(sb); 1368 fat_ent_access_init(sb); 1369 1370 /* 1371 * The low byte of FAT's first entry must have same value with 1372 * media-field. But in real world, too many devices is 1373 * writing wrong value. So, removed that validity check. 1374 * 1375 * if (FAT_FIRST_ENT(sb, media) != first) 1376 */ 1377 1378 error = -EINVAL; 1379 sprintf(buf, "cp%d", sbi->options.codepage); 1380 sbi->nls_disk = load_nls(buf); 1381 if (!sbi->nls_disk) { 1382 printk(KERN_ERR "FAT: codepage %s not found\n", buf); 1383 goto out_fail; 1384 } 1385 1386 /* FIXME: utf8 is using iocharset for upper/lower conversion */ 1387 if (sbi->options.isvfat) { 1388 sbi->nls_io = load_nls(sbi->options.iocharset); 1389 if (!sbi->nls_io) { 1390 printk(KERN_ERR "FAT: IO charset %s not found\n", 1391 sbi->options.iocharset); 1392 goto out_fail; 1393 } 1394 } 1395 1396 error = -ENOMEM; 1397 root_inode = new_inode(sb); 1398 if (!root_inode) 1399 goto out_fail; 1400 root_inode->i_ino = MSDOS_ROOT_INO; 1401 root_inode->i_version = 1; 1402 error = fat_read_root(root_inode); 1403 if (error < 0) 1404 goto out_fail; 1405 error = -ENOMEM; 1406 insert_inode_hash(root_inode); 1407 sb->s_root = d_alloc_root(root_inode); 1408 if (!sb->s_root) { 1409 printk(KERN_ERR "FAT: get root inode failed\n"); 1410 goto out_fail; 1411 } 1412 1413 return 0; 1414 1415 out_invalid: 1416 error = -EINVAL; 1417 if (!silent) 1418 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem" 1419 " on dev %s.\n", sb->s_id); 1420 1421 out_fail: 1422 if (root_inode) 1423 iput(root_inode); 1424 if (sbi->nls_io) 1425 unload_nls(sbi->nls_io); 1426 if (sbi->nls_disk) 1427 unload_nls(sbi->nls_disk); 1428 if (sbi->options.iocharset != fat_default_iocharset) 1429 kfree(sbi->options.iocharset); 1430 sb->s_fs_info = NULL; 1431 kfree(sbi); 1432 return error; 1433 } 1434 1435 EXPORT_SYMBOL_GPL(fat_fill_super); 1436 1437 int __init fat_cache_init(void); 1438 void fat_cache_destroy(void); 1439 1440 static int __init init_fat_fs(void) 1441 { 1442 int err; 1443 1444 err = fat_cache_init(); 1445 if (err) 1446 return err; 1447 1448 err = fat_init_inodecache(); 1449 if (err) 1450 goto failed; 1451 1452 return 0; 1453 1454 failed: 1455 fat_cache_destroy(); 1456 return err; 1457 } 1458 1459 static void __exit exit_fat_fs(void) 1460 { 1461 fat_cache_destroy(); 1462 fat_destroy_inodecache(); 1463 } 1464 1465 module_init(init_fat_fs) 1466 module_exit(exit_fat_fs) 1467 1468 MODULE_LICENSE("GPL"); 1469