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_error(sb, "corrupted file size (i_pos %lld, %lld)", 80 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private); 81 return -EIO; 82 } 83 84 offset = (unsigned long)iblock & (sbi->sec_per_clus - 1); 85 if (!offset) { 86 /* TODO: multiple cluster allocation would be desirable. */ 87 err = fat_add_cluster(inode); 88 if (err) 89 return err; 90 } 91 /* available blocks on this cluster */ 92 mapped_blocks = sbi->sec_per_clus - offset; 93 94 *max_blocks = min(mapped_blocks, *max_blocks); 95 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits; 96 97 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create); 98 if (err) 99 return err; 100 101 BUG_ON(!phys); 102 BUG_ON(*max_blocks != mapped_blocks); 103 set_buffer_new(bh_result); 104 map_bh(bh_result, sb, phys); 105 106 return 0; 107 } 108 109 static int fat_get_block(struct inode *inode, sector_t iblock, 110 struct buffer_head *bh_result, int create) 111 { 112 struct super_block *sb = inode->i_sb; 113 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits; 114 int err; 115 116 err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create); 117 if (err) 118 return err; 119 bh_result->b_size = max_blocks << sb->s_blocksize_bits; 120 return 0; 121 } 122 123 static int fat_writepage(struct page *page, struct writeback_control *wbc) 124 { 125 return block_write_full_page(page, fat_get_block, wbc); 126 } 127 128 static int fat_writepages(struct address_space *mapping, 129 struct writeback_control *wbc) 130 { 131 return mpage_writepages(mapping, wbc, fat_get_block); 132 } 133 134 static int fat_readpage(struct file *file, struct page *page) 135 { 136 return mpage_readpage(page, fat_get_block); 137 } 138 139 static int fat_readpages(struct file *file, struct address_space *mapping, 140 struct list_head *pages, unsigned nr_pages) 141 { 142 return mpage_readpages(mapping, pages, nr_pages, fat_get_block); 143 } 144 145 static 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 int err = 0; 455 456 if (sb->s_dirt) { 457 lock_super(sb); 458 sb->s_dirt = 0; 459 err = fat_clusters_flush(sb); 460 unlock_super(sb); 461 } 462 463 return err; 464 } 465 466 static void fat_put_super(struct super_block *sb) 467 { 468 struct msdos_sb_info *sbi = MSDOS_SB(sb); 469 470 lock_kernel(); 471 472 if (sb->s_dirt) 473 fat_write_super(sb); 474 475 iput(sbi->fat_inode); 476 477 unload_nls(sbi->nls_disk); 478 unload_nls(sbi->nls_io); 479 480 if (sbi->options.iocharset != fat_default_iocharset) 481 kfree(sbi->options.iocharset); 482 483 sb->s_fs_info = NULL; 484 kfree(sbi); 485 486 unlock_kernel(); 487 } 488 489 static struct kmem_cache *fat_inode_cachep; 490 491 static struct inode *fat_alloc_inode(struct super_block *sb) 492 { 493 struct msdos_inode_info *ei; 494 ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS); 495 if (!ei) 496 return NULL; 497 return &ei->vfs_inode; 498 } 499 500 static void fat_destroy_inode(struct inode *inode) 501 { 502 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode)); 503 } 504 505 static void init_once(void *foo) 506 { 507 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo; 508 509 spin_lock_init(&ei->cache_lru_lock); 510 ei->nr_caches = 0; 511 ei->cache_valid_id = FAT_CACHE_VALID + 1; 512 INIT_LIST_HEAD(&ei->cache_lru); 513 INIT_HLIST_NODE(&ei->i_fat_hash); 514 inode_init_once(&ei->vfs_inode); 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); 524 if (fat_inode_cachep == NULL) 525 return -ENOMEM; 526 return 0; 527 } 528 529 static void __exit fat_destroy_inodecache(void) 530 { 531 kmem_cache_destroy(fat_inode_cachep); 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 dentry *dentry, struct kstatfs *buf) 542 { 543 struct super_block *sb = dentry->d_sb; 544 struct msdos_sb_info *sbi = MSDOS_SB(sb); 545 u64 id = huge_encode_dev(sb->s_bdev->bd_dev); 546 547 /* If the count of free cluster is still unknown, counts it here. */ 548 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) { 549 int err = fat_count_free_clusters(dentry->d_sb); 550 if (err) 551 return err; 552 } 553 554 buf->f_type = dentry->d_sb->s_magic; 555 buf->f_bsize = sbi->cluster_size; 556 buf->f_blocks = sbi->max_cluster - FAT_START_ENT; 557 buf->f_bfree = sbi->free_clusters; 558 buf->f_bavail = sbi->free_clusters; 559 buf->f_fsid.val[0] = (u32)id; 560 buf->f_fsid.val[1] = (u32)(id >> 32); 561 buf->f_namelen = sbi->options.isvfat ? 260 : 12; 562 563 return 0; 564 } 565 566 static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi, 567 struct inode *inode) 568 { 569 loff_t i_pos; 570 #if BITS_PER_LONG == 32 571 spin_lock(&sbi->inode_hash_lock); 572 #endif 573 i_pos = MSDOS_I(inode)->i_pos; 574 #if BITS_PER_LONG == 32 575 spin_unlock(&sbi->inode_hash_lock); 576 #endif 577 return i_pos; 578 } 579 580 static int fat_write_inode(struct inode *inode, int wait) 581 { 582 struct super_block *sb = inode->i_sb; 583 struct msdos_sb_info *sbi = MSDOS_SB(sb); 584 struct buffer_head *bh; 585 struct msdos_dir_entry *raw_entry; 586 loff_t i_pos; 587 int err; 588 589 if (inode->i_ino == MSDOS_ROOT_INO) 590 return 0; 591 592 retry: 593 i_pos = fat_i_pos_read(sbi, inode); 594 if (!i_pos) 595 return 0; 596 597 bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits); 598 if (!bh) { 599 printk(KERN_ERR "FAT: unable to read inode block " 600 "for updating (i_pos %lld)\n", i_pos); 601 return -EIO; 602 } 603 spin_lock(&sbi->inode_hash_lock); 604 if (i_pos != MSDOS_I(inode)->i_pos) { 605 spin_unlock(&sbi->inode_hash_lock); 606 brelse(bh); 607 goto retry; 608 } 609 610 raw_entry = &((struct msdos_dir_entry *) (bh->b_data)) 611 [i_pos & (sbi->dir_per_block - 1)]; 612 if (S_ISDIR(inode->i_mode)) 613 raw_entry->size = 0; 614 else 615 raw_entry->size = cpu_to_le32(inode->i_size); 616 raw_entry->attr = fat_make_attrs(inode); 617 raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart); 618 raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16); 619 fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time, 620 &raw_entry->date, NULL); 621 if (sbi->options.isvfat) { 622 __le16 atime; 623 fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime, 624 &raw_entry->cdate, &raw_entry->ctime_cs); 625 fat_time_unix2fat(sbi, &inode->i_atime, &atime, 626 &raw_entry->adate, NULL); 627 } 628 spin_unlock(&sbi->inode_hash_lock); 629 mark_buffer_dirty(bh); 630 err = 0; 631 if (wait) 632 err = sync_dirty_buffer(bh); 633 brelse(bh); 634 return err; 635 } 636 637 int fat_sync_inode(struct inode *inode) 638 { 639 return fat_write_inode(inode, 1); 640 } 641 642 EXPORT_SYMBOL_GPL(fat_sync_inode); 643 644 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt); 645 static const struct super_operations fat_sops = { 646 .alloc_inode = fat_alloc_inode, 647 .destroy_inode = fat_destroy_inode, 648 .write_inode = fat_write_inode, 649 .delete_inode = fat_delete_inode, 650 .put_super = fat_put_super, 651 .write_super = fat_write_super, 652 .sync_fs = fat_sync_fs, 653 .statfs = fat_statfs, 654 .clear_inode = fat_clear_inode, 655 .remount_fs = fat_remount, 656 657 .show_options = fat_show_options, 658 }; 659 660 /* 661 * a FAT file handle with fhtype 3 is 662 * 0/ i_ino - for fast, reliable lookup if still in the cache 663 * 1/ i_generation - to see if i_ino is still valid 664 * bit 0 == 0 iff directory 665 * 2/ i_pos(8-39) - if ino has changed, but still in cache 666 * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos 667 * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc 668 * 669 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum 670 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits 671 * of i_logstart is used to store the directory entry offset. 672 */ 673 674 static struct dentry *fat_fh_to_dentry(struct super_block *sb, 675 struct fid *fid, int fh_len, int fh_type) 676 { 677 struct inode *inode = NULL; 678 struct dentry *result; 679 u32 *fh = fid->raw; 680 681 if (fh_len < 5 || fh_type != 3) 682 return NULL; 683 684 inode = ilookup(sb, fh[0]); 685 if (!inode || inode->i_generation != fh[1]) { 686 if (inode) 687 iput(inode); 688 inode = NULL; 689 } 690 if (!inode) { 691 loff_t i_pos; 692 int i_logstart = fh[3] & 0x0fffffff; 693 694 i_pos = (loff_t)fh[2] << 8; 695 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28); 696 697 /* try 2 - see if i_pos is in F-d-c 698 * require i_logstart to be the same 699 * Will fail if you truncate and then re-write 700 */ 701 702 inode = fat_iget(sb, i_pos); 703 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) { 704 iput(inode); 705 inode = NULL; 706 } 707 } 708 709 /* 710 * For now, do nothing if the inode is not found. 711 * 712 * What we could do is: 713 * 714 * - follow the file starting at fh[4], and record the ".." entry, 715 * and the name of the fh[2] entry. 716 * - then follow the ".." file finding the next step up. 717 * 718 * This way we build a path to the root of the tree. If this works, we 719 * lookup the path and so get this inode into the cache. Finally try 720 * the fat_iget lookup again. If that fails, then we are totally out 721 * of luck. But all that is for another day 722 */ 723 result = d_obtain_alias(inode); 724 if (!IS_ERR(result)) 725 result->d_op = sb->s_root->d_op; 726 return result; 727 } 728 729 static int 730 fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable) 731 { 732 int len = *lenp; 733 struct inode *inode = de->d_inode; 734 u32 ipos_h, ipos_m, ipos_l; 735 736 if (len < 5) 737 return 255; /* no room */ 738 739 ipos_h = MSDOS_I(inode)->i_pos >> 8; 740 ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24; 741 ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28; 742 *lenp = 5; 743 fh[0] = inode->i_ino; 744 fh[1] = inode->i_generation; 745 fh[2] = ipos_h; 746 fh[3] = ipos_m | MSDOS_I(inode)->i_logstart; 747 spin_lock(&de->d_lock); 748 fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart; 749 spin_unlock(&de->d_lock); 750 return 3; 751 } 752 753 static struct dentry *fat_get_parent(struct dentry *child) 754 { 755 struct super_block *sb = child->d_sb; 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_super(sb); 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(sb, de, i_pos); 771 brelse(bh); 772 773 parent = d_obtain_alias(inode); 774 if (!IS_ERR(parent)) 775 parent->d_op = sb->s_root->d_op; 776 out: 777 unlock_super(sb); 778 779 return parent; 780 } 781 782 static const struct export_operations fat_export_ops = { 783 .encode_fh = fat_encode_fh, 784 .fh_to_dentry = fat_fh_to_dentry, 785 .get_parent = fat_get_parent, 786 }; 787 788 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt) 789 { 790 struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb); 791 struct fat_mount_options *opts = &sbi->options; 792 int isvfat = opts->isvfat; 793 794 if (opts->fs_uid != 0) 795 seq_printf(m, ",uid=%u", opts->fs_uid); 796 if (opts->fs_gid != 0) 797 seq_printf(m, ",gid=%u", opts->fs_gid); 798 seq_printf(m, ",fmask=%04o", opts->fs_fmask); 799 seq_printf(m, ",dmask=%04o", opts->fs_dmask); 800 if (opts->allow_utime) 801 seq_printf(m, ",allow_utime=%04o", opts->allow_utime); 802 if (sbi->nls_disk) 803 seq_printf(m, ",codepage=%s", sbi->nls_disk->charset); 804 if (isvfat) { 805 if (sbi->nls_io) 806 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset); 807 808 switch (opts->shortname) { 809 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95: 810 seq_puts(m, ",shortname=win95"); 811 break; 812 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT: 813 seq_puts(m, ",shortname=winnt"); 814 break; 815 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95: 816 seq_puts(m, ",shortname=mixed"); 817 break; 818 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95: 819 seq_puts(m, ",shortname=lower"); 820 break; 821 default: 822 seq_puts(m, ",shortname=unknown"); 823 break; 824 } 825 } 826 if (opts->name_check != 'n') 827 seq_printf(m, ",check=%c", opts->name_check); 828 if (opts->usefree) 829 seq_puts(m, ",usefree"); 830 if (opts->quiet) 831 seq_puts(m, ",quiet"); 832 if (opts->showexec) 833 seq_puts(m, ",showexec"); 834 if (opts->sys_immutable) 835 seq_puts(m, ",sys_immutable"); 836 if (!isvfat) { 837 if (opts->dotsOK) 838 seq_puts(m, ",dotsOK=yes"); 839 if (opts->nocase) 840 seq_puts(m, ",nocase"); 841 } else { 842 if (opts->utf8) 843 seq_puts(m, ",utf8"); 844 if (opts->unicode_xlate) 845 seq_puts(m, ",uni_xlate"); 846 if (!opts->numtail) 847 seq_puts(m, ",nonumtail"); 848 if (opts->rodir) 849 seq_puts(m, ",rodir"); 850 } 851 if (opts->flush) 852 seq_puts(m, ",flush"); 853 if (opts->tz_utc) 854 seq_puts(m, ",tz=UTC"); 855 if (opts->errors == FAT_ERRORS_CONT) 856 seq_puts(m, ",errors=continue"); 857 else if (opts->errors == FAT_ERRORS_PANIC) 858 seq_puts(m, ",errors=panic"); 859 else 860 seq_puts(m, ",errors=remount-ro"); 861 if (opts->discard) 862 seq_puts(m, ",discard"); 863 864 return 0; 865 } 866 867 enum { 868 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid, 869 Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage, 870 Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug, 871 Opt_immutable, Opt_dots, Opt_nodots, 872 Opt_charset, Opt_shortname_lower, Opt_shortname_win95, 873 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes, 874 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes, 875 Opt_obsolate, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont, 876 Opt_err_panic, Opt_err_ro, Opt_discard, Opt_err, 877 }; 878 879 static const match_table_t fat_tokens = { 880 {Opt_check_r, "check=relaxed"}, 881 {Opt_check_s, "check=strict"}, 882 {Opt_check_n, "check=normal"}, 883 {Opt_check_r, "check=r"}, 884 {Opt_check_s, "check=s"}, 885 {Opt_check_n, "check=n"}, 886 {Opt_uid, "uid=%u"}, 887 {Opt_gid, "gid=%u"}, 888 {Opt_umask, "umask=%o"}, 889 {Opt_dmask, "dmask=%o"}, 890 {Opt_fmask, "fmask=%o"}, 891 {Opt_allow_utime, "allow_utime=%o"}, 892 {Opt_codepage, "codepage=%u"}, 893 {Opt_usefree, "usefree"}, 894 {Opt_nocase, "nocase"}, 895 {Opt_quiet, "quiet"}, 896 {Opt_showexec, "showexec"}, 897 {Opt_debug, "debug"}, 898 {Opt_immutable, "sys_immutable"}, 899 {Opt_flush, "flush"}, 900 {Opt_tz_utc, "tz=UTC"}, 901 {Opt_err_cont, "errors=continue"}, 902 {Opt_err_panic, "errors=panic"}, 903 {Opt_err_ro, "errors=remount-ro"}, 904 {Opt_discard, "discard"}, 905 {Opt_obsolate, "conv=binary"}, 906 {Opt_obsolate, "conv=text"}, 907 {Opt_obsolate, "conv=auto"}, 908 {Opt_obsolate, "conv=b"}, 909 {Opt_obsolate, "conv=t"}, 910 {Opt_obsolate, "conv=a"}, 911 {Opt_obsolate, "fat=%u"}, 912 {Opt_obsolate, "blocksize=%u"}, 913 {Opt_obsolate, "cvf_format=%20s"}, 914 {Opt_obsolate, "cvf_options=%100s"}, 915 {Opt_obsolate, "posix"}, 916 {Opt_err, NULL}, 917 }; 918 static const match_table_t msdos_tokens = { 919 {Opt_nodots, "nodots"}, 920 {Opt_nodots, "dotsOK=no"}, 921 {Opt_dots, "dots"}, 922 {Opt_dots, "dotsOK=yes"}, 923 {Opt_err, NULL} 924 }; 925 static const match_table_t vfat_tokens = { 926 {Opt_charset, "iocharset=%s"}, 927 {Opt_shortname_lower, "shortname=lower"}, 928 {Opt_shortname_win95, "shortname=win95"}, 929 {Opt_shortname_winnt, "shortname=winnt"}, 930 {Opt_shortname_mixed, "shortname=mixed"}, 931 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */ 932 {Opt_utf8_no, "utf8=no"}, 933 {Opt_utf8_no, "utf8=false"}, 934 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */ 935 {Opt_utf8_yes, "utf8=yes"}, 936 {Opt_utf8_yes, "utf8=true"}, 937 {Opt_utf8_yes, "utf8"}, 938 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */ 939 {Opt_uni_xl_no, "uni_xlate=no"}, 940 {Opt_uni_xl_no, "uni_xlate=false"}, 941 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */ 942 {Opt_uni_xl_yes, "uni_xlate=yes"}, 943 {Opt_uni_xl_yes, "uni_xlate=true"}, 944 {Opt_uni_xl_yes, "uni_xlate"}, 945 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */ 946 {Opt_nonumtail_no, "nonumtail=no"}, 947 {Opt_nonumtail_no, "nonumtail=false"}, 948 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */ 949 {Opt_nonumtail_yes, "nonumtail=yes"}, 950 {Opt_nonumtail_yes, "nonumtail=true"}, 951 {Opt_nonumtail_yes, "nonumtail"}, 952 {Opt_rodir, "rodir"}, 953 {Opt_err, NULL} 954 }; 955 956 static int parse_options(char *options, int is_vfat, int silent, int *debug, 957 struct fat_mount_options *opts) 958 { 959 char *p; 960 substring_t args[MAX_OPT_ARGS]; 961 int option; 962 char *iocharset; 963 964 opts->isvfat = is_vfat; 965 966 opts->fs_uid = current_uid(); 967 opts->fs_gid = current_gid(); 968 opts->fs_fmask = opts->fs_dmask = current_umask(); 969 opts->allow_utime = -1; 970 opts->codepage = fat_default_codepage; 971 opts->iocharset = fat_default_iocharset; 972 if (is_vfat) { 973 opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95; 974 opts->rodir = 0; 975 } else { 976 opts->shortname = 0; 977 opts->rodir = 1; 978 } 979 opts->name_check = 'n'; 980 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0; 981 opts->utf8 = opts->unicode_xlate = 0; 982 opts->numtail = 1; 983 opts->usefree = opts->nocase = 0; 984 opts->tz_utc = 0; 985 opts->errors = FAT_ERRORS_RO; 986 *debug = 0; 987 988 if (!options) 989 goto out; 990 991 while ((p = strsep(&options, ",")) != NULL) { 992 int token; 993 if (!*p) 994 continue; 995 996 token = match_token(p, fat_tokens, args); 997 if (token == Opt_err) { 998 if (is_vfat) 999 token = match_token(p, vfat_tokens, args); 1000 else 1001 token = match_token(p, msdos_tokens, args); 1002 } 1003 switch (token) { 1004 case Opt_check_s: 1005 opts->name_check = 's'; 1006 break; 1007 case Opt_check_r: 1008 opts->name_check = 'r'; 1009 break; 1010 case Opt_check_n: 1011 opts->name_check = 'n'; 1012 break; 1013 case Opt_usefree: 1014 opts->usefree = 1; 1015 break; 1016 case Opt_nocase: 1017 if (!is_vfat) 1018 opts->nocase = 1; 1019 else { 1020 /* for backward compatibility */ 1021 opts->shortname = VFAT_SFN_DISPLAY_WIN95 1022 | VFAT_SFN_CREATE_WIN95; 1023 } 1024 break; 1025 case Opt_quiet: 1026 opts->quiet = 1; 1027 break; 1028 case Opt_showexec: 1029 opts->showexec = 1; 1030 break; 1031 case Opt_debug: 1032 *debug = 1; 1033 break; 1034 case Opt_immutable: 1035 opts->sys_immutable = 1; 1036 break; 1037 case Opt_uid: 1038 if (match_int(&args[0], &option)) 1039 return 0; 1040 opts->fs_uid = option; 1041 break; 1042 case Opt_gid: 1043 if (match_int(&args[0], &option)) 1044 return 0; 1045 opts->fs_gid = option; 1046 break; 1047 case Opt_umask: 1048 if (match_octal(&args[0], &option)) 1049 return 0; 1050 opts->fs_fmask = opts->fs_dmask = option; 1051 break; 1052 case Opt_dmask: 1053 if (match_octal(&args[0], &option)) 1054 return 0; 1055 opts->fs_dmask = option; 1056 break; 1057 case Opt_fmask: 1058 if (match_octal(&args[0], &option)) 1059 return 0; 1060 opts->fs_fmask = option; 1061 break; 1062 case Opt_allow_utime: 1063 if (match_octal(&args[0], &option)) 1064 return 0; 1065 opts->allow_utime = option & (S_IWGRP | S_IWOTH); 1066 break; 1067 case Opt_codepage: 1068 if (match_int(&args[0], &option)) 1069 return 0; 1070 opts->codepage = option; 1071 break; 1072 case Opt_flush: 1073 opts->flush = 1; 1074 break; 1075 case Opt_tz_utc: 1076 opts->tz_utc = 1; 1077 break; 1078 case Opt_err_cont: 1079 opts->errors = FAT_ERRORS_CONT; 1080 break; 1081 case Opt_err_panic: 1082 opts->errors = FAT_ERRORS_PANIC; 1083 break; 1084 case Opt_err_ro: 1085 opts->errors = FAT_ERRORS_RO; 1086 break; 1087 1088 /* msdos specific */ 1089 case Opt_dots: 1090 opts->dotsOK = 1; 1091 break; 1092 case Opt_nodots: 1093 opts->dotsOK = 0; 1094 break; 1095 1096 /* vfat specific */ 1097 case Opt_charset: 1098 if (opts->iocharset != fat_default_iocharset) 1099 kfree(opts->iocharset); 1100 iocharset = match_strdup(&args[0]); 1101 if (!iocharset) 1102 return -ENOMEM; 1103 opts->iocharset = iocharset; 1104 break; 1105 case Opt_shortname_lower: 1106 opts->shortname = VFAT_SFN_DISPLAY_LOWER 1107 | VFAT_SFN_CREATE_WIN95; 1108 break; 1109 case Opt_shortname_win95: 1110 opts->shortname = VFAT_SFN_DISPLAY_WIN95 1111 | VFAT_SFN_CREATE_WIN95; 1112 break; 1113 case Opt_shortname_winnt: 1114 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1115 | VFAT_SFN_CREATE_WINNT; 1116 break; 1117 case Opt_shortname_mixed: 1118 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1119 | VFAT_SFN_CREATE_WIN95; 1120 break; 1121 case Opt_utf8_no: /* 0 or no or false */ 1122 opts->utf8 = 0; 1123 break; 1124 case Opt_utf8_yes: /* empty or 1 or yes or true */ 1125 opts->utf8 = 1; 1126 break; 1127 case Opt_uni_xl_no: /* 0 or no or false */ 1128 opts->unicode_xlate = 0; 1129 break; 1130 case Opt_uni_xl_yes: /* empty or 1 or yes or true */ 1131 opts->unicode_xlate = 1; 1132 break; 1133 case Opt_nonumtail_no: /* 0 or no or false */ 1134 opts->numtail = 1; /* negated option */ 1135 break; 1136 case Opt_nonumtail_yes: /* empty or 1 or yes or true */ 1137 opts->numtail = 0; /* negated option */ 1138 break; 1139 case Opt_rodir: 1140 opts->rodir = 1; 1141 break; 1142 case Opt_discard: 1143 opts->discard = 1; 1144 break; 1145 1146 /* obsolete mount options */ 1147 case Opt_obsolate: 1148 printk(KERN_INFO "FAT: \"%s\" option is obsolete, " 1149 "not supported now\n", p); 1150 break; 1151 /* unknown option */ 1152 default: 1153 if (!silent) { 1154 printk(KERN_ERR 1155 "FAT: Unrecognized mount option \"%s\" " 1156 "or missing value\n", p); 1157 } 1158 return -EINVAL; 1159 } 1160 } 1161 1162 out: 1163 /* UTF-8 doesn't provide FAT semantics */ 1164 if (!strcmp(opts->iocharset, "utf8")) { 1165 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset" 1166 " for FAT filesystems, filesystem will be " 1167 "case sensitive!\n"); 1168 } 1169 1170 /* If user doesn't specify allow_utime, it's initialized from dmask. */ 1171 if (opts->allow_utime == (unsigned short)-1) 1172 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH); 1173 if (opts->unicode_xlate) 1174 opts->utf8 = 0; 1175 1176 return 0; 1177 } 1178 1179 static int fat_read_root(struct inode *inode) 1180 { 1181 struct super_block *sb = inode->i_sb; 1182 struct msdos_sb_info *sbi = MSDOS_SB(sb); 1183 int error; 1184 1185 MSDOS_I(inode)->i_pos = 0; 1186 inode->i_uid = sbi->options.fs_uid; 1187 inode->i_gid = sbi->options.fs_gid; 1188 inode->i_version++; 1189 inode->i_generation = 0; 1190 inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO); 1191 inode->i_op = sbi->dir_ops; 1192 inode->i_fop = &fat_dir_operations; 1193 if (sbi->fat_bits == 32) { 1194 MSDOS_I(inode)->i_start = sbi->root_cluster; 1195 error = fat_calc_dir_size(inode); 1196 if (error < 0) 1197 return error; 1198 } else { 1199 MSDOS_I(inode)->i_start = 0; 1200 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry); 1201 } 1202 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 1203 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 1204 MSDOS_I(inode)->i_logstart = 0; 1205 MSDOS_I(inode)->mmu_private = inode->i_size; 1206 1207 fat_save_attrs(inode, ATTR_DIR); 1208 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0; 1209 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0; 1210 inode->i_nlink = fat_subdirs(inode)+2; 1211 1212 return 0; 1213 } 1214 1215 /* 1216 * Read the super block of an MS-DOS FS. 1217 */ 1218 int fat_fill_super(struct super_block *sb, void *data, int silent, 1219 const struct inode_operations *fs_dir_inode_ops, int isvfat) 1220 { 1221 struct inode *root_inode = NULL, *fat_inode = NULL; 1222 struct buffer_head *bh; 1223 struct fat_boot_sector *b; 1224 struct msdos_sb_info *sbi; 1225 u16 logical_sector_size; 1226 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors; 1227 int debug; 1228 unsigned int media; 1229 long error; 1230 char buf[50]; 1231 1232 /* 1233 * GFP_KERNEL is ok here, because while we do hold the 1234 * supeblock lock, memory pressure can't call back into 1235 * the filesystem, since we're only just about to mount 1236 * it and have no inodes etc active! 1237 */ 1238 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL); 1239 if (!sbi) 1240 return -ENOMEM; 1241 sb->s_fs_info = sbi; 1242 1243 sb->s_flags |= MS_NODIRATIME; 1244 sb->s_magic = MSDOS_SUPER_MAGIC; 1245 sb->s_op = &fat_sops; 1246 sb->s_export_op = &fat_export_ops; 1247 sbi->dir_ops = fs_dir_inode_ops; 1248 1249 error = parse_options(data, isvfat, silent, &debug, &sbi->options); 1250 if (error) 1251 goto out_fail; 1252 1253 error = -EIO; 1254 sb_min_blocksize(sb, 512); 1255 bh = sb_bread(sb, 0); 1256 if (bh == NULL) { 1257 printk(KERN_ERR "FAT: unable to read boot sector\n"); 1258 goto out_fail; 1259 } 1260 1261 b = (struct fat_boot_sector *) bh->b_data; 1262 if (!b->reserved) { 1263 if (!silent) 1264 printk(KERN_ERR "FAT: bogus number of reserved sectors\n"); 1265 brelse(bh); 1266 goto out_invalid; 1267 } 1268 if (!b->fats) { 1269 if (!silent) 1270 printk(KERN_ERR "FAT: bogus number of FAT structure\n"); 1271 brelse(bh); 1272 goto out_invalid; 1273 } 1274 1275 /* 1276 * Earlier we checked here that b->secs_track and b->head are nonzero, 1277 * but it turns out valid FAT filesystems can have zero there. 1278 */ 1279 1280 media = b->media; 1281 if (!fat_valid_media(media)) { 1282 if (!silent) 1283 printk(KERN_ERR "FAT: invalid media value (0x%02x)\n", 1284 media); 1285 brelse(bh); 1286 goto out_invalid; 1287 } 1288 logical_sector_size = get_unaligned_le16(&b->sector_size); 1289 if (!is_power_of_2(logical_sector_size) 1290 || (logical_sector_size < 512) 1291 || (logical_sector_size > 4096)) { 1292 if (!silent) 1293 printk(KERN_ERR "FAT: bogus logical sector size %u\n", 1294 logical_sector_size); 1295 brelse(bh); 1296 goto out_invalid; 1297 } 1298 sbi->sec_per_clus = b->sec_per_clus; 1299 if (!is_power_of_2(sbi->sec_per_clus)) { 1300 if (!silent) 1301 printk(KERN_ERR "FAT: bogus sectors per cluster %u\n", 1302 sbi->sec_per_clus); 1303 brelse(bh); 1304 goto out_invalid; 1305 } 1306 1307 if (logical_sector_size < sb->s_blocksize) { 1308 printk(KERN_ERR "FAT: logical sector size too small for device" 1309 " (logical sector size = %u)\n", logical_sector_size); 1310 brelse(bh); 1311 goto out_fail; 1312 } 1313 if (logical_sector_size > sb->s_blocksize) { 1314 brelse(bh); 1315 1316 if (!sb_set_blocksize(sb, logical_sector_size)) { 1317 printk(KERN_ERR "FAT: unable to set blocksize %u\n", 1318 logical_sector_size); 1319 goto out_fail; 1320 } 1321 bh = sb_bread(sb, 0); 1322 if (bh == NULL) { 1323 printk(KERN_ERR "FAT: unable to read boot sector" 1324 " (logical sector size = %lu)\n", 1325 sb->s_blocksize); 1326 goto out_fail; 1327 } 1328 b = (struct fat_boot_sector *) bh->b_data; 1329 } 1330 1331 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus; 1332 sbi->cluster_bits = ffs(sbi->cluster_size) - 1; 1333 sbi->fats = b->fats; 1334 sbi->fat_bits = 0; /* Don't know yet */ 1335 sbi->fat_start = le16_to_cpu(b->reserved); 1336 sbi->fat_length = le16_to_cpu(b->fat_length); 1337 sbi->root_cluster = 0; 1338 sbi->free_clusters = -1; /* Don't know yet */ 1339 sbi->free_clus_valid = 0; 1340 sbi->prev_free = FAT_START_ENT; 1341 1342 if (!sbi->fat_length && b->fat32_length) { 1343 struct fat_boot_fsinfo *fsinfo; 1344 struct buffer_head *fsinfo_bh; 1345 1346 /* Must be FAT32 */ 1347 sbi->fat_bits = 32; 1348 sbi->fat_length = le32_to_cpu(b->fat32_length); 1349 sbi->root_cluster = le32_to_cpu(b->root_cluster); 1350 1351 sb->s_maxbytes = 0xffffffff; 1352 1353 /* MC - if info_sector is 0, don't multiply by 0 */ 1354 sbi->fsinfo_sector = le16_to_cpu(b->info_sector); 1355 if (sbi->fsinfo_sector == 0) 1356 sbi->fsinfo_sector = 1; 1357 1358 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector); 1359 if (fsinfo_bh == NULL) { 1360 printk(KERN_ERR "FAT: bread failed, FSINFO block" 1361 " (sector = %lu)\n", sbi->fsinfo_sector); 1362 brelse(bh); 1363 goto out_fail; 1364 } 1365 1366 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data; 1367 if (!IS_FSINFO(fsinfo)) { 1368 printk(KERN_WARNING "FAT: Invalid FSINFO signature: " 1369 "0x%08x, 0x%08x (sector = %lu)\n", 1370 le32_to_cpu(fsinfo->signature1), 1371 le32_to_cpu(fsinfo->signature2), 1372 sbi->fsinfo_sector); 1373 } else { 1374 if (sbi->options.usefree) 1375 sbi->free_clus_valid = 1; 1376 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters); 1377 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster); 1378 } 1379 1380 brelse(fsinfo_bh); 1381 } 1382 1383 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry); 1384 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1; 1385 1386 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length; 1387 sbi->dir_entries = get_unaligned_le16(&b->dir_entries); 1388 if (sbi->dir_entries & (sbi->dir_per_block - 1)) { 1389 if (!silent) 1390 printk(KERN_ERR "FAT: bogus directroy-entries per block" 1391 " (%u)\n", sbi->dir_entries); 1392 brelse(bh); 1393 goto out_invalid; 1394 } 1395 1396 rootdir_sectors = sbi->dir_entries 1397 * sizeof(struct msdos_dir_entry) / sb->s_blocksize; 1398 sbi->data_start = sbi->dir_start + rootdir_sectors; 1399 total_sectors = get_unaligned_le16(&b->sectors); 1400 if (total_sectors == 0) 1401 total_sectors = le32_to_cpu(b->total_sect); 1402 1403 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus; 1404 1405 if (sbi->fat_bits != 32) 1406 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12; 1407 1408 /* check that FAT table does not overflow */ 1409 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits; 1410 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT); 1411 if (total_clusters > MAX_FAT(sb)) { 1412 if (!silent) 1413 printk(KERN_ERR "FAT: count of clusters too big (%u)\n", 1414 total_clusters); 1415 brelse(bh); 1416 goto out_invalid; 1417 } 1418 1419 sbi->max_cluster = total_clusters + FAT_START_ENT; 1420 /* check the free_clusters, it's not necessarily correct */ 1421 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters) 1422 sbi->free_clusters = -1; 1423 /* check the prev_free, it's not necessarily correct */ 1424 sbi->prev_free %= sbi->max_cluster; 1425 if (sbi->prev_free < FAT_START_ENT) 1426 sbi->prev_free = FAT_START_ENT; 1427 1428 brelse(bh); 1429 1430 /* set up enough so that it can read an inode */ 1431 fat_hash_init(sb); 1432 fat_ent_access_init(sb); 1433 1434 /* 1435 * The low byte of FAT's first entry must have same value with 1436 * media-field. But in real world, too many devices is 1437 * writing wrong value. So, removed that validity check. 1438 * 1439 * if (FAT_FIRST_ENT(sb, media) != first) 1440 */ 1441 1442 error = -EINVAL; 1443 sprintf(buf, "cp%d", sbi->options.codepage); 1444 sbi->nls_disk = load_nls(buf); 1445 if (!sbi->nls_disk) { 1446 printk(KERN_ERR "FAT: codepage %s not found\n", buf); 1447 goto out_fail; 1448 } 1449 1450 /* FIXME: utf8 is using iocharset for upper/lower conversion */ 1451 if (sbi->options.isvfat) { 1452 sbi->nls_io = load_nls(sbi->options.iocharset); 1453 if (!sbi->nls_io) { 1454 printk(KERN_ERR "FAT: IO charset %s not found\n", 1455 sbi->options.iocharset); 1456 goto out_fail; 1457 } 1458 } 1459 1460 error = -ENOMEM; 1461 fat_inode = new_inode(sb); 1462 if (!fat_inode) 1463 goto out_fail; 1464 MSDOS_I(fat_inode)->i_pos = 0; 1465 sbi->fat_inode = fat_inode; 1466 root_inode = new_inode(sb); 1467 if (!root_inode) 1468 goto out_fail; 1469 root_inode->i_ino = MSDOS_ROOT_INO; 1470 root_inode->i_version = 1; 1471 error = fat_read_root(root_inode); 1472 if (error < 0) 1473 goto out_fail; 1474 error = -ENOMEM; 1475 insert_inode_hash(root_inode); 1476 sb->s_root = d_alloc_root(root_inode); 1477 if (!sb->s_root) { 1478 printk(KERN_ERR "FAT: get root inode failed\n"); 1479 goto out_fail; 1480 } 1481 1482 return 0; 1483 1484 out_invalid: 1485 error = -EINVAL; 1486 if (!silent) 1487 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem" 1488 " on dev %s.\n", sb->s_id); 1489 1490 out_fail: 1491 if (fat_inode) 1492 iput(fat_inode); 1493 if (root_inode) 1494 iput(root_inode); 1495 if (sbi->nls_io) 1496 unload_nls(sbi->nls_io); 1497 if (sbi->nls_disk) 1498 unload_nls(sbi->nls_disk); 1499 if (sbi->options.iocharset != fat_default_iocharset) 1500 kfree(sbi->options.iocharset); 1501 sb->s_fs_info = NULL; 1502 kfree(sbi); 1503 return error; 1504 } 1505 1506 EXPORT_SYMBOL_GPL(fat_fill_super); 1507 1508 /* 1509 * helper function for fat_flush_inodes. This writes both the inode 1510 * and the file data blocks, waiting for in flight data blocks before 1511 * the start of the call. It does not wait for any io started 1512 * during the call 1513 */ 1514 static int writeback_inode(struct inode *inode) 1515 { 1516 1517 int ret; 1518 struct address_space *mapping = inode->i_mapping; 1519 struct writeback_control wbc = { 1520 .sync_mode = WB_SYNC_NONE, 1521 .nr_to_write = 0, 1522 }; 1523 /* if we used WB_SYNC_ALL, sync_inode waits for the io for the 1524 * inode to finish. So WB_SYNC_NONE is sent down to sync_inode 1525 * and filemap_fdatawrite is used for the data blocks 1526 */ 1527 ret = sync_inode(inode, &wbc); 1528 if (!ret) 1529 ret = filemap_fdatawrite(mapping); 1530 return ret; 1531 } 1532 1533 /* 1534 * write data and metadata corresponding to i1 and i2. The io is 1535 * started but we do not wait for any of it to finish. 1536 * 1537 * filemap_flush is used for the block device, so if there is a dirty 1538 * page for a block already in flight, we will not wait and start the 1539 * io over again 1540 */ 1541 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2) 1542 { 1543 int ret = 0; 1544 if (!MSDOS_SB(sb)->options.flush) 1545 return 0; 1546 if (i1) 1547 ret = writeback_inode(i1); 1548 if (!ret && i2) 1549 ret = writeback_inode(i2); 1550 if (!ret) { 1551 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping; 1552 ret = filemap_flush(mapping); 1553 } 1554 return ret; 1555 } 1556 EXPORT_SYMBOL_GPL(fat_flush_inodes); 1557 1558 static int __init init_fat_fs(void) 1559 { 1560 int err; 1561 1562 err = fat_cache_init(); 1563 if (err) 1564 return err; 1565 1566 err = fat_init_inodecache(); 1567 if (err) 1568 goto failed; 1569 1570 return 0; 1571 1572 failed: 1573 fat_cache_destroy(); 1574 return err; 1575 } 1576 1577 static void __exit exit_fat_fs(void) 1578 { 1579 fat_cache_destroy(); 1580 fat_destroy_inodecache(); 1581 } 1582 1583 module_init(init_fat_fs) 1584 module_exit(exit_fat_fs) 1585 1586 MODULE_LICENSE("GPL"); 1587