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/pagemap.h> 20 #include <linux/mpage.h> 21 #include <linux/buffer_head.h> 22 #include <linux/exportfs.h> 23 #include <linux/mount.h> 24 #include <linux/vfs.h> 25 #include <linux/parser.h> 26 #include <linux/uio.h> 27 #include <linux/writeback.h> 28 #include <linux/log2.h> 29 #include <linux/hash.h> 30 #include <asm/unaligned.h> 31 #include "fat.h" 32 33 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET 34 /* if user don't select VFAT, this is undefined. */ 35 #define CONFIG_FAT_DEFAULT_IOCHARSET "" 36 #endif 37 38 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE; 39 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET; 40 41 42 static int fat_add_cluster(struct inode *inode) 43 { 44 int err, cluster; 45 46 err = fat_alloc_clusters(inode, &cluster, 1); 47 if (err) 48 return err; 49 /* FIXME: this cluster should be added after data of this 50 * cluster is writed */ 51 err = fat_chain_add(inode, cluster, 1); 52 if (err) 53 fat_free_clusters(inode, cluster); 54 return err; 55 } 56 57 static inline int __fat_get_block(struct inode *inode, sector_t iblock, 58 unsigned long *max_blocks, 59 struct buffer_head *bh_result, int create) 60 { 61 struct super_block *sb = inode->i_sb; 62 struct msdos_sb_info *sbi = MSDOS_SB(sb); 63 unsigned long mapped_blocks; 64 sector_t phys; 65 int err, offset; 66 67 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create); 68 if (err) 69 return err; 70 if (phys) { 71 map_bh(bh_result, sb, phys); 72 *max_blocks = min(mapped_blocks, *max_blocks); 73 return 0; 74 } 75 if (!create) 76 return 0; 77 78 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) { 79 fat_fs_panic(sb, "corrupted file size (i_pos %lld, %lld)", 80 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private); 81 return -EIO; 82 } 83 84 offset = (unsigned long)iblock & (sbi->sec_per_clus - 1); 85 if (!offset) { 86 /* TODO: multiple cluster allocation would be desirable. */ 87 err = fat_add_cluster(inode); 88 if (err) 89 return err; 90 } 91 /* available blocks on this cluster */ 92 mapped_blocks = sbi->sec_per_clus - offset; 93 94 *max_blocks = min(mapped_blocks, *max_blocks); 95 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits; 96 97 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create); 98 if (err) 99 return err; 100 101 BUG_ON(!phys); 102 BUG_ON(*max_blocks != mapped_blocks); 103 set_buffer_new(bh_result); 104 map_bh(bh_result, sb, phys); 105 106 return 0; 107 } 108 109 static int fat_get_block(struct inode *inode, sector_t iblock, 110 struct buffer_head *bh_result, int create) 111 { 112 struct super_block *sb = inode->i_sb; 113 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits; 114 int err; 115 116 err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create); 117 if (err) 118 return err; 119 bh_result->b_size = max_blocks << sb->s_blocksize_bits; 120 return 0; 121 } 122 123 static int fat_writepage(struct page *page, struct writeback_control *wbc) 124 { 125 return block_write_full_page(page, fat_get_block, wbc); 126 } 127 128 static int fat_writepages(struct address_space *mapping, 129 struct writeback_control *wbc) 130 { 131 return mpage_writepages(mapping, wbc, fat_get_block); 132 } 133 134 static int fat_readpage(struct file *file, struct page *page) 135 { 136 return mpage_readpage(page, fat_get_block); 137 } 138 139 static int fat_readpages(struct file *file, struct address_space *mapping, 140 struct list_head *pages, unsigned nr_pages) 141 { 142 return mpage_readpages(mapping, pages, nr_pages, fat_get_block); 143 } 144 145 static int fat_write_begin(struct file *file, struct address_space *mapping, 146 loff_t pos, unsigned len, unsigned flags, 147 struct page **pagep, void **fsdata) 148 { 149 *pagep = NULL; 150 return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata, 151 fat_get_block, 152 &MSDOS_I(mapping->host)->mmu_private); 153 } 154 155 static int fat_write_end(struct file *file, struct address_space *mapping, 156 loff_t pos, unsigned len, unsigned copied, 157 struct page *pagep, void *fsdata) 158 { 159 struct inode *inode = mapping->host; 160 int err; 161 err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata); 162 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) { 163 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC; 164 MSDOS_I(inode)->i_attrs |= ATTR_ARCH; 165 mark_inode_dirty(inode); 166 } 167 return err; 168 } 169 170 static ssize_t fat_direct_IO(int rw, struct kiocb *iocb, 171 const struct iovec *iov, 172 loff_t offset, unsigned long nr_segs) 173 { 174 struct file *file = iocb->ki_filp; 175 struct inode *inode = file->f_mapping->host; 176 177 if (rw == WRITE) { 178 /* 179 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(), 180 * so we need to update the ->mmu_private to block boundary. 181 * 182 * But we must fill the remaining area or hole by nul for 183 * updating ->mmu_private. 184 * 185 * Return 0, and fallback to normal buffered write. 186 */ 187 loff_t size = offset + iov_length(iov, nr_segs); 188 if (MSDOS_I(inode)->mmu_private < size) 189 return 0; 190 } 191 192 /* 193 * FAT need to use the DIO_LOCKING for avoiding the race 194 * condition of fat_get_block() and ->truncate(). 195 */ 196 return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov, 197 offset, nr_segs, fat_get_block, NULL); 198 } 199 200 static sector_t _fat_bmap(struct address_space *mapping, sector_t block) 201 { 202 sector_t blocknr; 203 204 /* fat_get_cluster() assumes the requested blocknr isn't truncated. */ 205 down_read(&mapping->host->i_alloc_sem); 206 blocknr = generic_block_bmap(mapping, block, fat_get_block); 207 up_read(&mapping->host->i_alloc_sem); 208 209 return blocknr; 210 } 211 212 static const struct address_space_operations fat_aops = { 213 .readpage = fat_readpage, 214 .readpages = fat_readpages, 215 .writepage = fat_writepage, 216 .writepages = fat_writepages, 217 .sync_page = block_sync_page, 218 .write_begin = fat_write_begin, 219 .write_end = fat_write_end, 220 .direct_IO = fat_direct_IO, 221 .bmap = _fat_bmap 222 }; 223 224 /* 225 * New FAT inode stuff. We do the following: 226 * a) i_ino is constant and has nothing with on-disk location. 227 * b) FAT manages its own cache of directory entries. 228 * c) *This* cache is indexed by on-disk location. 229 * d) inode has an associated directory entry, all right, but 230 * it may be unhashed. 231 * e) currently entries are stored within struct inode. That should 232 * change. 233 * f) we deal with races in the following way: 234 * 1. readdir() and lookup() do FAT-dir-cache lookup. 235 * 2. rename() unhashes the F-d-c entry and rehashes it in 236 * a new place. 237 * 3. unlink() and rmdir() unhash F-d-c entry. 238 * 4. fat_write_inode() checks whether the thing is unhashed. 239 * If it is we silently return. If it isn't we do bread(), 240 * check if the location is still valid and retry if it 241 * isn't. Otherwise we do changes. 242 * 5. Spinlock is used to protect hash/unhash/location check/lookup 243 * 6. fat_clear_inode() unhashes the F-d-c entry. 244 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry 245 * and consider negative result as cache miss. 246 */ 247 248 static void fat_hash_init(struct super_block *sb) 249 { 250 struct msdos_sb_info *sbi = MSDOS_SB(sb); 251 int i; 252 253 spin_lock_init(&sbi->inode_hash_lock); 254 for (i = 0; i < FAT_HASH_SIZE; i++) 255 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]); 256 } 257 258 static inline unsigned long fat_hash(loff_t i_pos) 259 { 260 return hash_32(i_pos, FAT_HASH_BITS); 261 } 262 263 void fat_attach(struct inode *inode, loff_t i_pos) 264 { 265 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 266 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos); 267 268 spin_lock(&sbi->inode_hash_lock); 269 MSDOS_I(inode)->i_pos = i_pos; 270 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head); 271 spin_unlock(&sbi->inode_hash_lock); 272 } 273 EXPORT_SYMBOL_GPL(fat_attach); 274 275 void fat_detach(struct inode *inode) 276 { 277 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 278 spin_lock(&sbi->inode_hash_lock); 279 MSDOS_I(inode)->i_pos = 0; 280 hlist_del_init(&MSDOS_I(inode)->i_fat_hash); 281 spin_unlock(&sbi->inode_hash_lock); 282 } 283 EXPORT_SYMBOL_GPL(fat_detach); 284 285 struct inode *fat_iget(struct super_block *sb, loff_t i_pos) 286 { 287 struct msdos_sb_info *sbi = MSDOS_SB(sb); 288 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos); 289 struct hlist_node *_p; 290 struct msdos_inode_info *i; 291 struct inode *inode = NULL; 292 293 spin_lock(&sbi->inode_hash_lock); 294 hlist_for_each_entry(i, _p, head, i_fat_hash) { 295 BUG_ON(i->vfs_inode.i_sb != sb); 296 if (i->i_pos != i_pos) 297 continue; 298 inode = igrab(&i->vfs_inode); 299 if (inode) 300 break; 301 } 302 spin_unlock(&sbi->inode_hash_lock); 303 return inode; 304 } 305 306 static int is_exec(unsigned char *extension) 307 { 308 unsigned char *exe_extensions = "EXECOMBAT", *walk; 309 310 for (walk = exe_extensions; *walk; walk += 3) 311 if (!strncmp(extension, walk, 3)) 312 return 1; 313 return 0; 314 } 315 316 static int fat_calc_dir_size(struct inode *inode) 317 { 318 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 319 int ret, fclus, dclus; 320 321 inode->i_size = 0; 322 if (MSDOS_I(inode)->i_start == 0) 323 return 0; 324 325 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); 326 if (ret < 0) 327 return ret; 328 inode->i_size = (fclus + 1) << sbi->cluster_bits; 329 330 return 0; 331 } 332 333 /* doesn't deal with root inode */ 334 static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de) 335 { 336 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 337 int error; 338 339 MSDOS_I(inode)->i_pos = 0; 340 inode->i_uid = sbi->options.fs_uid; 341 inode->i_gid = sbi->options.fs_gid; 342 inode->i_version++; 343 inode->i_generation = get_seconds(); 344 345 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) { 346 inode->i_generation &= ~1; 347 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO); 348 inode->i_op = sbi->dir_ops; 349 inode->i_fop = &fat_dir_operations; 350 351 MSDOS_I(inode)->i_start = le16_to_cpu(de->start); 352 if (sbi->fat_bits == 32) 353 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16); 354 355 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 356 error = fat_calc_dir_size(inode); 357 if (error < 0) 358 return error; 359 MSDOS_I(inode)->mmu_private = inode->i_size; 360 361 inode->i_nlink = fat_subdirs(inode); 362 } else { /* not a directory */ 363 inode->i_generation |= 1; 364 inode->i_mode = fat_make_mode(sbi, de->attr, 365 ((sbi->options.showexec && !is_exec(de->name + 8)) 366 ? S_IRUGO|S_IWUGO : S_IRWXUGO)); 367 MSDOS_I(inode)->i_start = le16_to_cpu(de->start); 368 if (sbi->fat_bits == 32) 369 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16); 370 371 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 372 inode->i_size = le32_to_cpu(de->size); 373 inode->i_op = &fat_file_inode_operations; 374 inode->i_fop = &fat_file_operations; 375 inode->i_mapping->a_ops = &fat_aops; 376 MSDOS_I(inode)->mmu_private = inode->i_size; 377 } 378 if (de->attr & ATTR_SYS) { 379 if (sbi->options.sys_immutable) 380 inode->i_flags |= S_IMMUTABLE; 381 } 382 fat_save_attrs(inode, de->attr); 383 384 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 385 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 386 387 fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0); 388 if (sbi->options.isvfat) { 389 fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime, 390 de->cdate, de->ctime_cs); 391 fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0); 392 } else 393 inode->i_ctime = inode->i_atime = inode->i_mtime; 394 395 return 0; 396 } 397 398 struct inode *fat_build_inode(struct super_block *sb, 399 struct msdos_dir_entry *de, loff_t i_pos) 400 { 401 struct inode *inode; 402 int err; 403 404 inode = fat_iget(sb, i_pos); 405 if (inode) 406 goto out; 407 inode = new_inode(sb); 408 if (!inode) { 409 inode = ERR_PTR(-ENOMEM); 410 goto out; 411 } 412 inode->i_ino = iunique(sb, MSDOS_ROOT_INO); 413 inode->i_version = 1; 414 err = fat_fill_inode(inode, de); 415 if (err) { 416 iput(inode); 417 inode = ERR_PTR(err); 418 goto out; 419 } 420 fat_attach(inode, i_pos); 421 insert_inode_hash(inode); 422 out: 423 return inode; 424 } 425 426 EXPORT_SYMBOL_GPL(fat_build_inode); 427 428 static void fat_delete_inode(struct inode *inode) 429 { 430 truncate_inode_pages(&inode->i_data, 0); 431 inode->i_size = 0; 432 fat_truncate(inode); 433 clear_inode(inode); 434 } 435 436 static void fat_clear_inode(struct inode *inode) 437 { 438 fat_cache_inval_inode(inode); 439 fat_detach(inode); 440 } 441 442 static void fat_write_super(struct super_block *sb) 443 { 444 lock_super(sb); 445 sb->s_dirt = 0; 446 447 if (!(sb->s_flags & MS_RDONLY)) 448 fat_clusters_flush(sb); 449 unlock_super(sb); 450 } 451 452 static int fat_sync_fs(struct super_block *sb, int wait) 453 { 454 lock_super(sb); 455 fat_clusters_flush(sb); 456 sb->s_dirt = 0; 457 unlock_super(sb); 458 459 return 0; 460 } 461 462 static void fat_put_super(struct super_block *sb) 463 { 464 struct msdos_sb_info *sbi = MSDOS_SB(sb); 465 466 lock_kernel(); 467 468 if (sb->s_dirt) 469 fat_write_super(sb); 470 471 iput(sbi->fat_inode); 472 473 if (sbi->nls_disk) { 474 unload_nls(sbi->nls_disk); 475 sbi->nls_disk = NULL; 476 sbi->options.codepage = fat_default_codepage; 477 } 478 if (sbi->nls_io) { 479 unload_nls(sbi->nls_io); 480 sbi->nls_io = NULL; 481 } 482 if (sbi->options.iocharset != fat_default_iocharset) { 483 kfree(sbi->options.iocharset); 484 sbi->options.iocharset = fat_default_iocharset; 485 } 486 487 sb->s_fs_info = NULL; 488 kfree(sbi); 489 490 unlock_kernel(); 491 } 492 493 static struct kmem_cache *fat_inode_cachep; 494 495 static struct inode *fat_alloc_inode(struct super_block *sb) 496 { 497 struct msdos_inode_info *ei; 498 ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS); 499 if (!ei) 500 return NULL; 501 return &ei->vfs_inode; 502 } 503 504 static void fat_destroy_inode(struct inode *inode) 505 { 506 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode)); 507 } 508 509 static void init_once(void *foo) 510 { 511 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo; 512 513 spin_lock_init(&ei->cache_lru_lock); 514 ei->nr_caches = 0; 515 ei->cache_valid_id = FAT_CACHE_VALID + 1; 516 INIT_LIST_HEAD(&ei->cache_lru); 517 INIT_HLIST_NODE(&ei->i_fat_hash); 518 inode_init_once(&ei->vfs_inode); 519 } 520 521 static int __init fat_init_inodecache(void) 522 { 523 fat_inode_cachep = kmem_cache_create("fat_inode_cache", 524 sizeof(struct msdos_inode_info), 525 0, (SLAB_RECLAIM_ACCOUNT| 526 SLAB_MEM_SPREAD), 527 init_once); 528 if (fat_inode_cachep == NULL) 529 return -ENOMEM; 530 return 0; 531 } 532 533 static void __exit fat_destroy_inodecache(void) 534 { 535 kmem_cache_destroy(fat_inode_cachep); 536 } 537 538 static int fat_remount(struct super_block *sb, int *flags, char *data) 539 { 540 struct msdos_sb_info *sbi = MSDOS_SB(sb); 541 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME); 542 return 0; 543 } 544 545 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf) 546 { 547 struct super_block *sb = dentry->d_sb; 548 struct msdos_sb_info *sbi = MSDOS_SB(sb); 549 u64 id = huge_encode_dev(sb->s_bdev->bd_dev); 550 551 /* If the count of free cluster is still unknown, counts it here. */ 552 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) { 553 int err = fat_count_free_clusters(dentry->d_sb); 554 if (err) 555 return err; 556 } 557 558 buf->f_type = dentry->d_sb->s_magic; 559 buf->f_bsize = sbi->cluster_size; 560 buf->f_blocks = sbi->max_cluster - FAT_START_ENT; 561 buf->f_bfree = sbi->free_clusters; 562 buf->f_bavail = sbi->free_clusters; 563 buf->f_fsid.val[0] = (u32)id; 564 buf->f_fsid.val[1] = (u32)(id >> 32); 565 buf->f_namelen = sbi->options.isvfat ? 260 : 12; 566 567 return 0; 568 } 569 570 static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi, 571 struct inode *inode) 572 { 573 loff_t i_pos; 574 #if BITS_PER_LONG == 32 575 spin_lock(&sbi->inode_hash_lock); 576 #endif 577 i_pos = MSDOS_I(inode)->i_pos; 578 #if BITS_PER_LONG == 32 579 spin_unlock(&sbi->inode_hash_lock); 580 #endif 581 return i_pos; 582 } 583 584 static int fat_write_inode(struct inode *inode, int wait) 585 { 586 struct super_block *sb = inode->i_sb; 587 struct msdos_sb_info *sbi = MSDOS_SB(sb); 588 struct buffer_head *bh; 589 struct msdos_dir_entry *raw_entry; 590 loff_t i_pos; 591 int err; 592 593 if (inode->i_ino == MSDOS_ROOT_INO) 594 return 0; 595 596 retry: 597 i_pos = fat_i_pos_read(sbi, inode); 598 if (!i_pos) 599 return 0; 600 601 bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits); 602 if (!bh) { 603 printk(KERN_ERR "FAT: unable to read inode block " 604 "for updating (i_pos %lld)\n", i_pos); 605 return -EIO; 606 } 607 spin_lock(&sbi->inode_hash_lock); 608 if (i_pos != MSDOS_I(inode)->i_pos) { 609 spin_unlock(&sbi->inode_hash_lock); 610 brelse(bh); 611 goto retry; 612 } 613 614 raw_entry = &((struct msdos_dir_entry *) (bh->b_data)) 615 [i_pos & (sbi->dir_per_block - 1)]; 616 if (S_ISDIR(inode->i_mode)) 617 raw_entry->size = 0; 618 else 619 raw_entry->size = cpu_to_le32(inode->i_size); 620 raw_entry->attr = fat_make_attrs(inode); 621 raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart); 622 raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16); 623 fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time, 624 &raw_entry->date, NULL); 625 if (sbi->options.isvfat) { 626 __le16 atime; 627 fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime, 628 &raw_entry->cdate, &raw_entry->ctime_cs); 629 fat_time_unix2fat(sbi, &inode->i_atime, &atime, 630 &raw_entry->adate, NULL); 631 } 632 spin_unlock(&sbi->inode_hash_lock); 633 mark_buffer_dirty(bh); 634 err = 0; 635 if (wait) 636 err = sync_dirty_buffer(bh); 637 brelse(bh); 638 return err; 639 } 640 641 int fat_sync_inode(struct inode *inode) 642 { 643 return fat_write_inode(inode, 1); 644 } 645 646 EXPORT_SYMBOL_GPL(fat_sync_inode); 647 648 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt); 649 static const struct super_operations fat_sops = { 650 .alloc_inode = fat_alloc_inode, 651 .destroy_inode = fat_destroy_inode, 652 .write_inode = fat_write_inode, 653 .delete_inode = fat_delete_inode, 654 .put_super = fat_put_super, 655 .write_super = fat_write_super, 656 .sync_fs = fat_sync_fs, 657 .statfs = fat_statfs, 658 .clear_inode = fat_clear_inode, 659 .remount_fs = fat_remount, 660 661 .show_options = fat_show_options, 662 }; 663 664 /* 665 * a FAT file handle with fhtype 3 is 666 * 0/ i_ino - for fast, reliable lookup if still in the cache 667 * 1/ i_generation - to see if i_ino is still valid 668 * bit 0 == 0 iff directory 669 * 2/ i_pos(8-39) - if ino has changed, but still in cache 670 * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos 671 * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc 672 * 673 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum 674 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits 675 * of i_logstart is used to store the directory entry offset. 676 */ 677 678 static struct dentry *fat_fh_to_dentry(struct super_block *sb, 679 struct fid *fid, int fh_len, int fh_type) 680 { 681 struct inode *inode = NULL; 682 struct dentry *result; 683 u32 *fh = fid->raw; 684 685 if (fh_len < 5 || fh_type != 3) 686 return NULL; 687 688 inode = ilookup(sb, fh[0]); 689 if (!inode || inode->i_generation != fh[1]) { 690 if (inode) 691 iput(inode); 692 inode = NULL; 693 } 694 if (!inode) { 695 loff_t i_pos; 696 int i_logstart = fh[3] & 0x0fffffff; 697 698 i_pos = (loff_t)fh[2] << 8; 699 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28); 700 701 /* try 2 - see if i_pos is in F-d-c 702 * require i_logstart to be the same 703 * Will fail if you truncate and then re-write 704 */ 705 706 inode = fat_iget(sb, i_pos); 707 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) { 708 iput(inode); 709 inode = NULL; 710 } 711 } 712 713 /* 714 * For now, do nothing if the inode is not found. 715 * 716 * What we could do is: 717 * 718 * - follow the file starting at fh[4], and record the ".." entry, 719 * and the name of the fh[2] entry. 720 * - then follow the ".." file finding the next step up. 721 * 722 * This way we build a path to the root of the tree. If this works, we 723 * lookup the path and so get this inode into the cache. Finally try 724 * the fat_iget lookup again. If that fails, then we are totally out 725 * of luck. But all that is for another day 726 */ 727 result = d_obtain_alias(inode); 728 if (!IS_ERR(result)) 729 result->d_op = sb->s_root->d_op; 730 return result; 731 } 732 733 static int 734 fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable) 735 { 736 int len = *lenp; 737 struct inode *inode = de->d_inode; 738 u32 ipos_h, ipos_m, ipos_l; 739 740 if (len < 5) 741 return 255; /* no room */ 742 743 ipos_h = MSDOS_I(inode)->i_pos >> 8; 744 ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24; 745 ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28; 746 *lenp = 5; 747 fh[0] = inode->i_ino; 748 fh[1] = inode->i_generation; 749 fh[2] = ipos_h; 750 fh[3] = ipos_m | MSDOS_I(inode)->i_logstart; 751 spin_lock(&de->d_lock); 752 fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart; 753 spin_unlock(&de->d_lock); 754 return 3; 755 } 756 757 static struct dentry *fat_get_parent(struct dentry *child) 758 { 759 struct super_block *sb = child->d_sb; 760 struct buffer_head *bh; 761 struct msdos_dir_entry *de; 762 loff_t i_pos; 763 struct dentry *parent; 764 struct inode *inode; 765 int err; 766 767 lock_super(sb); 768 769 err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos); 770 if (err) { 771 parent = ERR_PTR(err); 772 goto out; 773 } 774 inode = fat_build_inode(sb, de, i_pos); 775 brelse(bh); 776 777 parent = d_obtain_alias(inode); 778 if (!IS_ERR(parent)) 779 parent->d_op = sb->s_root->d_op; 780 out: 781 unlock_super(sb); 782 783 return parent; 784 } 785 786 static const struct export_operations fat_export_ops = { 787 .encode_fh = fat_encode_fh, 788 .fh_to_dentry = fat_fh_to_dentry, 789 .get_parent = fat_get_parent, 790 }; 791 792 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt) 793 { 794 struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb); 795 struct fat_mount_options *opts = &sbi->options; 796 int isvfat = opts->isvfat; 797 798 if (opts->fs_uid != 0) 799 seq_printf(m, ",uid=%u", opts->fs_uid); 800 if (opts->fs_gid != 0) 801 seq_printf(m, ",gid=%u", opts->fs_gid); 802 seq_printf(m, ",fmask=%04o", opts->fs_fmask); 803 seq_printf(m, ",dmask=%04o", opts->fs_dmask); 804 if (opts->allow_utime) 805 seq_printf(m, ",allow_utime=%04o", opts->allow_utime); 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->usefree) 833 seq_puts(m, ",usefree"); 834 if (opts->quiet) 835 seq_puts(m, ",quiet"); 836 if (opts->showexec) 837 seq_puts(m, ",showexec"); 838 if (opts->sys_immutable) 839 seq_puts(m, ",sys_immutable"); 840 if (!isvfat) { 841 if (opts->dotsOK) 842 seq_puts(m, ",dotsOK=yes"); 843 if (opts->nocase) 844 seq_puts(m, ",nocase"); 845 } else { 846 if (opts->utf8) 847 seq_puts(m, ",utf8"); 848 if (opts->unicode_xlate) 849 seq_puts(m, ",uni_xlate"); 850 if (!opts->numtail) 851 seq_puts(m, ",nonumtail"); 852 if (opts->rodir) 853 seq_puts(m, ",rodir"); 854 } 855 if (opts->flush) 856 seq_puts(m, ",flush"); 857 if (opts->tz_utc) 858 seq_puts(m, ",tz=UTC"); 859 860 return 0; 861 } 862 863 enum { 864 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid, 865 Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage, 866 Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug, 867 Opt_immutable, Opt_dots, Opt_nodots, 868 Opt_charset, Opt_shortname_lower, Opt_shortname_win95, 869 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes, 870 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes, 871 Opt_obsolate, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err, 872 }; 873 874 static const match_table_t fat_tokens = { 875 {Opt_check_r, "check=relaxed"}, 876 {Opt_check_s, "check=strict"}, 877 {Opt_check_n, "check=normal"}, 878 {Opt_check_r, "check=r"}, 879 {Opt_check_s, "check=s"}, 880 {Opt_check_n, "check=n"}, 881 {Opt_uid, "uid=%u"}, 882 {Opt_gid, "gid=%u"}, 883 {Opt_umask, "umask=%o"}, 884 {Opt_dmask, "dmask=%o"}, 885 {Opt_fmask, "fmask=%o"}, 886 {Opt_allow_utime, "allow_utime=%o"}, 887 {Opt_codepage, "codepage=%u"}, 888 {Opt_usefree, "usefree"}, 889 {Opt_nocase, "nocase"}, 890 {Opt_quiet, "quiet"}, 891 {Opt_showexec, "showexec"}, 892 {Opt_debug, "debug"}, 893 {Opt_immutable, "sys_immutable"}, 894 {Opt_obsolate, "conv=binary"}, 895 {Opt_obsolate, "conv=text"}, 896 {Opt_obsolate, "conv=auto"}, 897 {Opt_obsolate, "conv=b"}, 898 {Opt_obsolate, "conv=t"}, 899 {Opt_obsolate, "conv=a"}, 900 {Opt_obsolate, "fat=%u"}, 901 {Opt_obsolate, "blocksize=%u"}, 902 {Opt_obsolate, "cvf_format=%20s"}, 903 {Opt_obsolate, "cvf_options=%100s"}, 904 {Opt_obsolate, "posix"}, 905 {Opt_flush, "flush"}, 906 {Opt_tz_utc, "tz=UTC"}, 907 {Opt_err, NULL}, 908 }; 909 static const match_table_t msdos_tokens = { 910 {Opt_nodots, "nodots"}, 911 {Opt_nodots, "dotsOK=no"}, 912 {Opt_dots, "dots"}, 913 {Opt_dots, "dotsOK=yes"}, 914 {Opt_err, NULL} 915 }; 916 static const match_table_t vfat_tokens = { 917 {Opt_charset, "iocharset=%s"}, 918 {Opt_shortname_lower, "shortname=lower"}, 919 {Opt_shortname_win95, "shortname=win95"}, 920 {Opt_shortname_winnt, "shortname=winnt"}, 921 {Opt_shortname_mixed, "shortname=mixed"}, 922 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */ 923 {Opt_utf8_no, "utf8=no"}, 924 {Opt_utf8_no, "utf8=false"}, 925 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */ 926 {Opt_utf8_yes, "utf8=yes"}, 927 {Opt_utf8_yes, "utf8=true"}, 928 {Opt_utf8_yes, "utf8"}, 929 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */ 930 {Opt_uni_xl_no, "uni_xlate=no"}, 931 {Opt_uni_xl_no, "uni_xlate=false"}, 932 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */ 933 {Opt_uni_xl_yes, "uni_xlate=yes"}, 934 {Opt_uni_xl_yes, "uni_xlate=true"}, 935 {Opt_uni_xl_yes, "uni_xlate"}, 936 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */ 937 {Opt_nonumtail_no, "nonumtail=no"}, 938 {Opt_nonumtail_no, "nonumtail=false"}, 939 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */ 940 {Opt_nonumtail_yes, "nonumtail=yes"}, 941 {Opt_nonumtail_yes, "nonumtail=true"}, 942 {Opt_nonumtail_yes, "nonumtail"}, 943 {Opt_rodir, "rodir"}, 944 {Opt_err, NULL} 945 }; 946 947 static int parse_options(char *options, int is_vfat, int silent, int *debug, 948 struct fat_mount_options *opts) 949 { 950 char *p; 951 substring_t args[MAX_OPT_ARGS]; 952 int option; 953 char *iocharset; 954 955 opts->isvfat = is_vfat; 956 957 opts->fs_uid = current_uid(); 958 opts->fs_gid = current_gid(); 959 opts->fs_fmask = current_umask(); 960 opts->allow_utime = -1; 961 opts->codepage = fat_default_codepage; 962 opts->iocharset = fat_default_iocharset; 963 if (is_vfat) { 964 opts->shortname = VFAT_SFN_DISPLAY_LOWER|VFAT_SFN_CREATE_WIN95; 965 opts->rodir = 0; 966 } else { 967 opts->shortname = 0; 968 opts->rodir = 1; 969 } 970 opts->name_check = 'n'; 971 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0; 972 opts->utf8 = opts->unicode_xlate = 0; 973 opts->numtail = 1; 974 opts->usefree = opts->nocase = 0; 975 opts->tz_utc = 0; 976 *debug = 0; 977 978 if (!options) 979 goto out; 980 981 while ((p = strsep(&options, ",")) != NULL) { 982 int token; 983 if (!*p) 984 continue; 985 986 token = match_token(p, fat_tokens, args); 987 if (token == Opt_err) { 988 if (is_vfat) 989 token = match_token(p, vfat_tokens, args); 990 else 991 token = match_token(p, msdos_tokens, args); 992 } 993 switch (token) { 994 case Opt_check_s: 995 opts->name_check = 's'; 996 break; 997 case Opt_check_r: 998 opts->name_check = 'r'; 999 break; 1000 case Opt_check_n: 1001 opts->name_check = 'n'; 1002 break; 1003 case Opt_usefree: 1004 opts->usefree = 1; 1005 break; 1006 case Opt_nocase: 1007 if (!is_vfat) 1008 opts->nocase = 1; 1009 else { 1010 /* for backward compatibility */ 1011 opts->shortname = VFAT_SFN_DISPLAY_WIN95 1012 | VFAT_SFN_CREATE_WIN95; 1013 } 1014 break; 1015 case Opt_quiet: 1016 opts->quiet = 1; 1017 break; 1018 case Opt_showexec: 1019 opts->showexec = 1; 1020 break; 1021 case Opt_debug: 1022 *debug = 1; 1023 break; 1024 case Opt_immutable: 1025 opts->sys_immutable = 1; 1026 break; 1027 case Opt_uid: 1028 if (match_int(&args[0], &option)) 1029 return 0; 1030 opts->fs_uid = option; 1031 break; 1032 case Opt_gid: 1033 if (match_int(&args[0], &option)) 1034 return 0; 1035 opts->fs_gid = option; 1036 break; 1037 case Opt_umask: 1038 if (match_octal(&args[0], &option)) 1039 return 0; 1040 opts->fs_fmask = opts->fs_dmask = option; 1041 break; 1042 case Opt_dmask: 1043 if (match_octal(&args[0], &option)) 1044 return 0; 1045 opts->fs_dmask = option; 1046 break; 1047 case Opt_fmask: 1048 if (match_octal(&args[0], &option)) 1049 return 0; 1050 opts->fs_fmask = option; 1051 break; 1052 case Opt_allow_utime: 1053 if (match_octal(&args[0], &option)) 1054 return 0; 1055 opts->allow_utime = option & (S_IWGRP | S_IWOTH); 1056 break; 1057 case Opt_codepage: 1058 if (match_int(&args[0], &option)) 1059 return 0; 1060 opts->codepage = option; 1061 break; 1062 case Opt_flush: 1063 opts->flush = 1; 1064 break; 1065 case Opt_tz_utc: 1066 opts->tz_utc = 1; 1067 break; 1068 1069 /* msdos specific */ 1070 case Opt_dots: 1071 opts->dotsOK = 1; 1072 break; 1073 case Opt_nodots: 1074 opts->dotsOK = 0; 1075 break; 1076 1077 /* vfat specific */ 1078 case Opt_charset: 1079 if (opts->iocharset != fat_default_iocharset) 1080 kfree(opts->iocharset); 1081 iocharset = match_strdup(&args[0]); 1082 if (!iocharset) 1083 return -ENOMEM; 1084 opts->iocharset = iocharset; 1085 break; 1086 case Opt_shortname_lower: 1087 opts->shortname = VFAT_SFN_DISPLAY_LOWER 1088 | VFAT_SFN_CREATE_WIN95; 1089 break; 1090 case Opt_shortname_win95: 1091 opts->shortname = VFAT_SFN_DISPLAY_WIN95 1092 | VFAT_SFN_CREATE_WIN95; 1093 break; 1094 case Opt_shortname_winnt: 1095 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1096 | VFAT_SFN_CREATE_WINNT; 1097 break; 1098 case Opt_shortname_mixed: 1099 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1100 | VFAT_SFN_CREATE_WIN95; 1101 break; 1102 case Opt_utf8_no: /* 0 or no or false */ 1103 opts->utf8 = 0; 1104 break; 1105 case Opt_utf8_yes: /* empty or 1 or yes or true */ 1106 opts->utf8 = 1; 1107 break; 1108 case Opt_uni_xl_no: /* 0 or no or false */ 1109 opts->unicode_xlate = 0; 1110 break; 1111 case Opt_uni_xl_yes: /* empty or 1 or yes or true */ 1112 opts->unicode_xlate = 1; 1113 break; 1114 case Opt_nonumtail_no: /* 0 or no or false */ 1115 opts->numtail = 1; /* negated option */ 1116 break; 1117 case Opt_nonumtail_yes: /* empty or 1 or yes or true */ 1118 opts->numtail = 0; /* negated option */ 1119 break; 1120 case Opt_rodir: 1121 opts->rodir = 1; 1122 break; 1123 1124 /* obsolete mount options */ 1125 case Opt_obsolate: 1126 printk(KERN_INFO "FAT: \"%s\" option is obsolete, " 1127 "not supported now\n", p); 1128 break; 1129 /* unknown option */ 1130 default: 1131 if (!silent) { 1132 printk(KERN_ERR 1133 "FAT: Unrecognized mount option \"%s\" " 1134 "or missing value\n", p); 1135 } 1136 return -EINVAL; 1137 } 1138 } 1139 1140 out: 1141 /* UTF-8 doesn't provide FAT semantics */ 1142 if (!strcmp(opts->iocharset, "utf8")) { 1143 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset" 1144 " for FAT filesystems, filesystem will be " 1145 "case sensitive!\n"); 1146 } 1147 1148 /* If user doesn't specify allow_utime, it's initialized from dmask. */ 1149 if (opts->allow_utime == (unsigned short)-1) 1150 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH); 1151 if (opts->unicode_xlate) 1152 opts->utf8 = 0; 1153 1154 return 0; 1155 } 1156 1157 static int fat_read_root(struct inode *inode) 1158 { 1159 struct super_block *sb = inode->i_sb; 1160 struct msdos_sb_info *sbi = MSDOS_SB(sb); 1161 int error; 1162 1163 MSDOS_I(inode)->i_pos = 0; 1164 inode->i_uid = sbi->options.fs_uid; 1165 inode->i_gid = sbi->options.fs_gid; 1166 inode->i_version++; 1167 inode->i_generation = 0; 1168 inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO); 1169 inode->i_op = sbi->dir_ops; 1170 inode->i_fop = &fat_dir_operations; 1171 if (sbi->fat_bits == 32) { 1172 MSDOS_I(inode)->i_start = sbi->root_cluster; 1173 error = fat_calc_dir_size(inode); 1174 if (error < 0) 1175 return error; 1176 } else { 1177 MSDOS_I(inode)->i_start = 0; 1178 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry); 1179 } 1180 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 1181 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 1182 MSDOS_I(inode)->i_logstart = 0; 1183 MSDOS_I(inode)->mmu_private = inode->i_size; 1184 1185 fat_save_attrs(inode, ATTR_DIR); 1186 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0; 1187 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0; 1188 inode->i_nlink = fat_subdirs(inode)+2; 1189 1190 return 0; 1191 } 1192 1193 /* 1194 * Read the super block of an MS-DOS FS. 1195 */ 1196 int fat_fill_super(struct super_block *sb, void *data, int silent, 1197 const struct inode_operations *fs_dir_inode_ops, int isvfat) 1198 { 1199 struct inode *root_inode = NULL, *fat_inode = NULL; 1200 struct buffer_head *bh; 1201 struct fat_boot_sector *b; 1202 struct msdos_sb_info *sbi; 1203 u16 logical_sector_size; 1204 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors; 1205 int debug; 1206 unsigned int media; 1207 long error; 1208 char buf[50]; 1209 1210 /* 1211 * GFP_KERNEL is ok here, because while we do hold the 1212 * supeblock lock, memory pressure can't call back into 1213 * the filesystem, since we're only just about to mount 1214 * it and have no inodes etc active! 1215 */ 1216 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL); 1217 if (!sbi) 1218 return -ENOMEM; 1219 sb->s_fs_info = sbi; 1220 1221 sb->s_flags |= MS_NODIRATIME; 1222 sb->s_magic = MSDOS_SUPER_MAGIC; 1223 sb->s_op = &fat_sops; 1224 sb->s_export_op = &fat_export_ops; 1225 sbi->dir_ops = fs_dir_inode_ops; 1226 1227 error = parse_options(data, isvfat, silent, &debug, &sbi->options); 1228 if (error) 1229 goto out_fail; 1230 1231 error = -EIO; 1232 sb_min_blocksize(sb, 512); 1233 bh = sb_bread(sb, 0); 1234 if (bh == NULL) { 1235 printk(KERN_ERR "FAT: unable to read boot sector\n"); 1236 goto out_fail; 1237 } 1238 1239 b = (struct fat_boot_sector *) bh->b_data; 1240 if (!b->reserved) { 1241 if (!silent) 1242 printk(KERN_ERR "FAT: bogus number of reserved sectors\n"); 1243 brelse(bh); 1244 goto out_invalid; 1245 } 1246 if (!b->fats) { 1247 if (!silent) 1248 printk(KERN_ERR "FAT: bogus number of FAT structure\n"); 1249 brelse(bh); 1250 goto out_invalid; 1251 } 1252 1253 /* 1254 * Earlier we checked here that b->secs_track and b->head are nonzero, 1255 * but it turns out valid FAT filesystems can have zero there. 1256 */ 1257 1258 media = b->media; 1259 if (!fat_valid_media(media)) { 1260 if (!silent) 1261 printk(KERN_ERR "FAT: invalid media value (0x%02x)\n", 1262 media); 1263 brelse(bh); 1264 goto out_invalid; 1265 } 1266 logical_sector_size = get_unaligned_le16(&b->sector_size); 1267 if (!is_power_of_2(logical_sector_size) 1268 || (logical_sector_size < 512) 1269 || (logical_sector_size > 4096)) { 1270 if (!silent) 1271 printk(KERN_ERR "FAT: bogus logical sector size %u\n", 1272 logical_sector_size); 1273 brelse(bh); 1274 goto out_invalid; 1275 } 1276 sbi->sec_per_clus = b->sec_per_clus; 1277 if (!is_power_of_2(sbi->sec_per_clus)) { 1278 if (!silent) 1279 printk(KERN_ERR "FAT: bogus sectors per cluster %u\n", 1280 sbi->sec_per_clus); 1281 brelse(bh); 1282 goto out_invalid; 1283 } 1284 1285 if (logical_sector_size < sb->s_blocksize) { 1286 printk(KERN_ERR "FAT: logical sector size too small for device" 1287 " (logical sector size = %u)\n", logical_sector_size); 1288 brelse(bh); 1289 goto out_fail; 1290 } 1291 if (logical_sector_size > sb->s_blocksize) { 1292 brelse(bh); 1293 1294 if (!sb_set_blocksize(sb, logical_sector_size)) { 1295 printk(KERN_ERR "FAT: unable to set blocksize %u\n", 1296 logical_sector_size); 1297 goto out_fail; 1298 } 1299 bh = sb_bread(sb, 0); 1300 if (bh == NULL) { 1301 printk(KERN_ERR "FAT: unable to read boot sector" 1302 " (logical sector size = %lu)\n", 1303 sb->s_blocksize); 1304 goto out_fail; 1305 } 1306 b = (struct fat_boot_sector *) bh->b_data; 1307 } 1308 1309 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus; 1310 sbi->cluster_bits = ffs(sbi->cluster_size) - 1; 1311 sbi->fats = b->fats; 1312 sbi->fat_bits = 0; /* Don't know yet */ 1313 sbi->fat_start = le16_to_cpu(b->reserved); 1314 sbi->fat_length = le16_to_cpu(b->fat_length); 1315 sbi->root_cluster = 0; 1316 sbi->free_clusters = -1; /* Don't know yet */ 1317 sbi->free_clus_valid = 0; 1318 sbi->prev_free = FAT_START_ENT; 1319 1320 if (!sbi->fat_length && b->fat32_length) { 1321 struct fat_boot_fsinfo *fsinfo; 1322 struct buffer_head *fsinfo_bh; 1323 1324 /* Must be FAT32 */ 1325 sbi->fat_bits = 32; 1326 sbi->fat_length = le32_to_cpu(b->fat32_length); 1327 sbi->root_cluster = le32_to_cpu(b->root_cluster); 1328 1329 sb->s_maxbytes = 0xffffffff; 1330 1331 /* MC - if info_sector is 0, don't multiply by 0 */ 1332 sbi->fsinfo_sector = le16_to_cpu(b->info_sector); 1333 if (sbi->fsinfo_sector == 0) 1334 sbi->fsinfo_sector = 1; 1335 1336 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector); 1337 if (fsinfo_bh == NULL) { 1338 printk(KERN_ERR "FAT: bread failed, FSINFO block" 1339 " (sector = %lu)\n", sbi->fsinfo_sector); 1340 brelse(bh); 1341 goto out_fail; 1342 } 1343 1344 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data; 1345 if (!IS_FSINFO(fsinfo)) { 1346 printk(KERN_WARNING "FAT: Invalid FSINFO signature: " 1347 "0x%08x, 0x%08x (sector = %lu)\n", 1348 le32_to_cpu(fsinfo->signature1), 1349 le32_to_cpu(fsinfo->signature2), 1350 sbi->fsinfo_sector); 1351 } else { 1352 if (sbi->options.usefree) 1353 sbi->free_clus_valid = 1; 1354 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters); 1355 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster); 1356 } 1357 1358 brelse(fsinfo_bh); 1359 } 1360 1361 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry); 1362 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1; 1363 1364 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length; 1365 sbi->dir_entries = get_unaligned_le16(&b->dir_entries); 1366 if (sbi->dir_entries & (sbi->dir_per_block - 1)) { 1367 if (!silent) 1368 printk(KERN_ERR "FAT: bogus directroy-entries per block" 1369 " (%u)\n", sbi->dir_entries); 1370 brelse(bh); 1371 goto out_invalid; 1372 } 1373 1374 rootdir_sectors = sbi->dir_entries 1375 * sizeof(struct msdos_dir_entry) / sb->s_blocksize; 1376 sbi->data_start = sbi->dir_start + rootdir_sectors; 1377 total_sectors = get_unaligned_le16(&b->sectors); 1378 if (total_sectors == 0) 1379 total_sectors = le32_to_cpu(b->total_sect); 1380 1381 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus; 1382 1383 if (sbi->fat_bits != 32) 1384 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12; 1385 1386 /* check that FAT table does not overflow */ 1387 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits; 1388 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT); 1389 if (total_clusters > MAX_FAT(sb)) { 1390 if (!silent) 1391 printk(KERN_ERR "FAT: count of clusters too big (%u)\n", 1392 total_clusters); 1393 brelse(bh); 1394 goto out_invalid; 1395 } 1396 1397 sbi->max_cluster = total_clusters + FAT_START_ENT; 1398 /* check the free_clusters, it's not necessarily correct */ 1399 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters) 1400 sbi->free_clusters = -1; 1401 /* check the prev_free, it's not necessarily correct */ 1402 sbi->prev_free %= sbi->max_cluster; 1403 if (sbi->prev_free < FAT_START_ENT) 1404 sbi->prev_free = FAT_START_ENT; 1405 1406 brelse(bh); 1407 1408 /* set up enough so that it can read an inode */ 1409 fat_hash_init(sb); 1410 fat_ent_access_init(sb); 1411 1412 /* 1413 * The low byte of FAT's first entry must have same value with 1414 * media-field. But in real world, too many devices is 1415 * writing wrong value. So, removed that validity check. 1416 * 1417 * if (FAT_FIRST_ENT(sb, media) != first) 1418 */ 1419 1420 error = -EINVAL; 1421 sprintf(buf, "cp%d", sbi->options.codepage); 1422 sbi->nls_disk = load_nls(buf); 1423 if (!sbi->nls_disk) { 1424 printk(KERN_ERR "FAT: codepage %s not found\n", buf); 1425 goto out_fail; 1426 } 1427 1428 /* FIXME: utf8 is using iocharset for upper/lower conversion */ 1429 if (sbi->options.isvfat) { 1430 sbi->nls_io = load_nls(sbi->options.iocharset); 1431 if (!sbi->nls_io) { 1432 printk(KERN_ERR "FAT: IO charset %s not found\n", 1433 sbi->options.iocharset); 1434 goto out_fail; 1435 } 1436 } 1437 1438 error = -ENOMEM; 1439 fat_inode = new_inode(sb); 1440 if (!fat_inode) 1441 goto out_fail; 1442 MSDOS_I(fat_inode)->i_pos = 0; 1443 sbi->fat_inode = fat_inode; 1444 root_inode = new_inode(sb); 1445 if (!root_inode) 1446 goto out_fail; 1447 root_inode->i_ino = MSDOS_ROOT_INO; 1448 root_inode->i_version = 1; 1449 error = fat_read_root(root_inode); 1450 if (error < 0) 1451 goto out_fail; 1452 error = -ENOMEM; 1453 insert_inode_hash(root_inode); 1454 sb->s_root = d_alloc_root(root_inode); 1455 if (!sb->s_root) { 1456 printk(KERN_ERR "FAT: get root inode failed\n"); 1457 goto out_fail; 1458 } 1459 1460 return 0; 1461 1462 out_invalid: 1463 error = -EINVAL; 1464 if (!silent) 1465 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem" 1466 " on dev %s.\n", sb->s_id); 1467 1468 out_fail: 1469 if (fat_inode) 1470 iput(fat_inode); 1471 if (root_inode) 1472 iput(root_inode); 1473 if (sbi->nls_io) 1474 unload_nls(sbi->nls_io); 1475 if (sbi->nls_disk) 1476 unload_nls(sbi->nls_disk); 1477 if (sbi->options.iocharset != fat_default_iocharset) 1478 kfree(sbi->options.iocharset); 1479 sb->s_fs_info = NULL; 1480 kfree(sbi); 1481 return error; 1482 } 1483 1484 EXPORT_SYMBOL_GPL(fat_fill_super); 1485 1486 /* 1487 * helper function for fat_flush_inodes. This writes both the inode 1488 * and the file data blocks, waiting for in flight data blocks before 1489 * the start of the call. It does not wait for any io started 1490 * during the call 1491 */ 1492 static int writeback_inode(struct inode *inode) 1493 { 1494 1495 int ret; 1496 struct address_space *mapping = inode->i_mapping; 1497 struct writeback_control wbc = { 1498 .sync_mode = WB_SYNC_NONE, 1499 .nr_to_write = 0, 1500 }; 1501 /* if we used WB_SYNC_ALL, sync_inode waits for the io for the 1502 * inode to finish. So WB_SYNC_NONE is sent down to sync_inode 1503 * and filemap_fdatawrite is used for the data blocks 1504 */ 1505 ret = sync_inode(inode, &wbc); 1506 if (!ret) 1507 ret = filemap_fdatawrite(mapping); 1508 return ret; 1509 } 1510 1511 /* 1512 * write data and metadata corresponding to i1 and i2. The io is 1513 * started but we do not wait for any of it to finish. 1514 * 1515 * filemap_flush is used for the block device, so if there is a dirty 1516 * page for a block already in flight, we will not wait and start the 1517 * io over again 1518 */ 1519 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2) 1520 { 1521 int ret = 0; 1522 if (!MSDOS_SB(sb)->options.flush) 1523 return 0; 1524 if (i1) 1525 ret = writeback_inode(i1); 1526 if (!ret && i2) 1527 ret = writeback_inode(i2); 1528 if (!ret) { 1529 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping; 1530 ret = filemap_flush(mapping); 1531 } 1532 return ret; 1533 } 1534 EXPORT_SYMBOL_GPL(fat_flush_inodes); 1535 1536 static int __init init_fat_fs(void) 1537 { 1538 int err; 1539 1540 err = fat_cache_init(); 1541 if (err) 1542 return err; 1543 1544 err = fat_init_inodecache(); 1545 if (err) 1546 goto failed; 1547 1548 return 0; 1549 1550 failed: 1551 fat_cache_destroy(); 1552 return err; 1553 } 1554 1555 static void __exit exit_fat_fs(void) 1556 { 1557 fat_cache_destroy(); 1558 fat_destroy_inodecache(); 1559 } 1560 1561 module_init(init_fat_fs) 1562 module_exit(exit_fat_fs) 1563 1564 MODULE_LICENSE("GPL"); 1565