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 <linux/writeback.h> 28 #include <linux/log2.h> 29 #include <asm/unaligned.h> 30 31 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET 32 /* if user don't select VFAT, this is undefined. */ 33 #define CONFIG_FAT_DEFAULT_IOCHARSET "" 34 #endif 35 36 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE; 37 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET; 38 39 40 static int fat_add_cluster(struct inode *inode) 41 { 42 int err, cluster; 43 44 err = fat_alloc_clusters(inode, &cluster, 1); 45 if (err) 46 return err; 47 /* FIXME: this cluster should be added after data of this 48 * cluster is writed */ 49 err = fat_chain_add(inode, cluster, 1); 50 if (err) 51 fat_free_clusters(inode, cluster); 52 return err; 53 } 54 55 static inline int __fat_get_block(struct inode *inode, sector_t iblock, 56 unsigned long *max_blocks, 57 struct buffer_head *bh_result, int create) 58 { 59 struct super_block *sb = inode->i_sb; 60 struct msdos_sb_info *sbi = MSDOS_SB(sb); 61 unsigned long mapped_blocks; 62 sector_t phys; 63 int err, offset; 64 65 err = fat_bmap(inode, iblock, &phys, &mapped_blocks); 66 if (err) 67 return err; 68 if (phys) { 69 map_bh(bh_result, sb, phys); 70 *max_blocks = min(mapped_blocks, *max_blocks); 71 return 0; 72 } 73 if (!create) 74 return 0; 75 76 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) { 77 fat_fs_panic(sb, "corrupted file size (i_pos %lld, %lld)", 78 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private); 79 return -EIO; 80 } 81 82 offset = (unsigned long)iblock & (sbi->sec_per_clus - 1); 83 if (!offset) { 84 /* TODO: multiple cluster allocation would be desirable. */ 85 err = fat_add_cluster(inode); 86 if (err) 87 return err; 88 } 89 /* available blocks on this cluster */ 90 mapped_blocks = sbi->sec_per_clus - offset; 91 92 *max_blocks = min(mapped_blocks, *max_blocks); 93 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits; 94 95 err = fat_bmap(inode, iblock, &phys, &mapped_blocks); 96 if (err) 97 return err; 98 99 BUG_ON(!phys); 100 BUG_ON(*max_blocks != mapped_blocks); 101 set_buffer_new(bh_result); 102 map_bh(bh_result, sb, phys); 103 104 return 0; 105 } 106 107 static int fat_get_block(struct inode *inode, sector_t iblock, 108 struct buffer_head *bh_result, int create) 109 { 110 struct super_block *sb = inode->i_sb; 111 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits; 112 int err; 113 114 err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create); 115 if (err) 116 return err; 117 bh_result->b_size = max_blocks << sb->s_blocksize_bits; 118 return 0; 119 } 120 121 static int fat_writepage(struct page *page, struct writeback_control *wbc) 122 { 123 return block_write_full_page(page, fat_get_block, wbc); 124 } 125 126 static int fat_writepages(struct address_space *mapping, 127 struct writeback_control *wbc) 128 { 129 return mpage_writepages(mapping, wbc, fat_get_block); 130 } 131 132 static int fat_readpage(struct file *file, struct page *page) 133 { 134 return mpage_readpage(page, fat_get_block); 135 } 136 137 static int fat_readpages(struct file *file, struct address_space *mapping, 138 struct list_head *pages, unsigned nr_pages) 139 { 140 return mpage_readpages(mapping, pages, nr_pages, fat_get_block); 141 } 142 143 static int fat_prepare_write(struct file *file, struct page *page, 144 unsigned from, unsigned to) 145 { 146 return cont_prepare_write(page, from, to, fat_get_block, 147 &MSDOS_I(page->mapping->host)->mmu_private); 148 } 149 150 static int fat_commit_write(struct file *file, struct page *page, 151 unsigned from, unsigned to) 152 { 153 struct inode *inode = page->mapping->host; 154 int err = generic_commit_write(file, page, from, to); 155 if (!err && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) { 156 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC; 157 MSDOS_I(inode)->i_attrs |= ATTR_ARCH; 158 mark_inode_dirty(inode); 159 } 160 return err; 161 } 162 163 static ssize_t fat_direct_IO(int rw, struct kiocb *iocb, 164 const struct iovec *iov, 165 loff_t offset, unsigned long nr_segs) 166 { 167 struct file *file = iocb->ki_filp; 168 struct inode *inode = file->f_mapping->host; 169 170 if (rw == WRITE) { 171 /* 172 * FIXME: blockdev_direct_IO() doesn't use ->prepare_write(), 173 * so we need to update the ->mmu_private to block boundary. 174 * 175 * But we must fill the remaining area or hole by nul for 176 * updating ->mmu_private. 177 * 178 * Return 0, and fallback to normal buffered write. 179 */ 180 loff_t size = offset + iov_length(iov, nr_segs); 181 if (MSDOS_I(inode)->mmu_private < size) 182 return 0; 183 } 184 185 /* 186 * FAT need to use the DIO_LOCKING for avoiding the race 187 * condition of fat_get_block() and ->truncate(). 188 */ 189 return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov, 190 offset, nr_segs, fat_get_block, NULL); 191 } 192 193 static sector_t _fat_bmap(struct address_space *mapping, sector_t block) 194 { 195 return generic_block_bmap(mapping, block, fat_get_block); 196 } 197 198 static const struct address_space_operations fat_aops = { 199 .readpage = fat_readpage, 200 .readpages = fat_readpages, 201 .writepage = fat_writepage, 202 .writepages = fat_writepages, 203 .sync_page = block_sync_page, 204 .prepare_write = fat_prepare_write, 205 .commit_write = fat_commit_write, 206 .direct_IO = fat_direct_IO, 207 .bmap = _fat_bmap 208 }; 209 210 /* 211 * New FAT inode stuff. We do the following: 212 * a) i_ino is constant and has nothing with on-disk location. 213 * b) FAT manages its own cache of directory entries. 214 * c) *This* cache is indexed by on-disk location. 215 * d) inode has an associated directory entry, all right, but 216 * it may be unhashed. 217 * e) currently entries are stored within struct inode. That should 218 * change. 219 * f) we deal with races in the following way: 220 * 1. readdir() and lookup() do FAT-dir-cache lookup. 221 * 2. rename() unhashes the F-d-c entry and rehashes it in 222 * a new place. 223 * 3. unlink() and rmdir() unhash F-d-c entry. 224 * 4. fat_write_inode() checks whether the thing is unhashed. 225 * If it is we silently return. If it isn't we do bread(), 226 * check if the location is still valid and retry if it 227 * isn't. Otherwise we do changes. 228 * 5. Spinlock is used to protect hash/unhash/location check/lookup 229 * 6. fat_clear_inode() unhashes the F-d-c entry. 230 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry 231 * and consider negative result as cache miss. 232 */ 233 234 static void fat_hash_init(struct super_block *sb) 235 { 236 struct msdos_sb_info *sbi = MSDOS_SB(sb); 237 int i; 238 239 spin_lock_init(&sbi->inode_hash_lock); 240 for (i = 0; i < FAT_HASH_SIZE; i++) 241 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]); 242 } 243 244 static inline unsigned long fat_hash(struct super_block *sb, loff_t i_pos) 245 { 246 unsigned long tmp = (unsigned long)i_pos | (unsigned long) sb; 247 tmp = tmp + (tmp >> FAT_HASH_BITS) + (tmp >> FAT_HASH_BITS * 2); 248 return tmp & FAT_HASH_MASK; 249 } 250 251 void fat_attach(struct inode *inode, loff_t i_pos) 252 { 253 struct super_block *sb = inode->i_sb; 254 struct msdos_sb_info *sbi = MSDOS_SB(sb); 255 256 spin_lock(&sbi->inode_hash_lock); 257 MSDOS_I(inode)->i_pos = i_pos; 258 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, 259 sbi->inode_hashtable + fat_hash(sb, i_pos)); 260 spin_unlock(&sbi->inode_hash_lock); 261 } 262 263 EXPORT_SYMBOL_GPL(fat_attach); 264 265 void fat_detach(struct inode *inode) 266 { 267 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 268 spin_lock(&sbi->inode_hash_lock); 269 MSDOS_I(inode)->i_pos = 0; 270 hlist_del_init(&MSDOS_I(inode)->i_fat_hash); 271 spin_unlock(&sbi->inode_hash_lock); 272 } 273 274 EXPORT_SYMBOL_GPL(fat_detach); 275 276 struct inode *fat_iget(struct super_block *sb, loff_t i_pos) 277 { 278 struct msdos_sb_info *sbi = MSDOS_SB(sb); 279 struct hlist_head *head = sbi->inode_hashtable + fat_hash(sb, i_pos); 280 struct hlist_node *_p; 281 struct msdos_inode_info *i; 282 struct inode *inode = NULL; 283 284 spin_lock(&sbi->inode_hash_lock); 285 hlist_for_each_entry(i, _p, head, i_fat_hash) { 286 BUG_ON(i->vfs_inode.i_sb != sb); 287 if (i->i_pos != i_pos) 288 continue; 289 inode = igrab(&i->vfs_inode); 290 if (inode) 291 break; 292 } 293 spin_unlock(&sbi->inode_hash_lock); 294 return inode; 295 } 296 297 static int is_exec(unsigned char *extension) 298 { 299 unsigned char *exe_extensions = "EXECOMBAT", *walk; 300 301 for (walk = exe_extensions; *walk; walk += 3) 302 if (!strncmp(extension, walk, 3)) 303 return 1; 304 return 0; 305 } 306 307 static int fat_calc_dir_size(struct inode *inode) 308 { 309 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 310 int ret, fclus, dclus; 311 312 inode->i_size = 0; 313 if (MSDOS_I(inode)->i_start == 0) 314 return 0; 315 316 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); 317 if (ret < 0) 318 return ret; 319 inode->i_size = (fclus + 1) << sbi->cluster_bits; 320 321 return 0; 322 } 323 324 /* doesn't deal with root inode */ 325 static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de) 326 { 327 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 328 int error; 329 330 MSDOS_I(inode)->i_pos = 0; 331 inode->i_uid = sbi->options.fs_uid; 332 inode->i_gid = sbi->options.fs_gid; 333 inode->i_version++; 334 inode->i_generation = get_seconds(); 335 336 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) { 337 inode->i_generation &= ~1; 338 inode->i_mode = MSDOS_MKMODE(de->attr, 339 S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR; 340 inode->i_op = sbi->dir_ops; 341 inode->i_fop = &fat_dir_operations; 342 343 MSDOS_I(inode)->i_start = le16_to_cpu(de->start); 344 if (sbi->fat_bits == 32) 345 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16); 346 347 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 348 error = fat_calc_dir_size(inode); 349 if (error < 0) 350 return error; 351 MSDOS_I(inode)->mmu_private = inode->i_size; 352 353 inode->i_nlink = fat_subdirs(inode); 354 } else { /* not a directory */ 355 inode->i_generation |= 1; 356 inode->i_mode = MSDOS_MKMODE(de->attr, 357 ((sbi->options.showexec && 358 !is_exec(de->ext)) 359 ? S_IRUGO|S_IWUGO : S_IRWXUGO) 360 & ~sbi->options.fs_fmask) | S_IFREG; 361 MSDOS_I(inode)->i_start = le16_to_cpu(de->start); 362 if (sbi->fat_bits == 32) 363 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16); 364 365 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 366 inode->i_size = le32_to_cpu(de->size); 367 inode->i_op = &fat_file_inode_operations; 368 inode->i_fop = &fat_file_operations; 369 inode->i_mapping->a_ops = &fat_aops; 370 MSDOS_I(inode)->mmu_private = inode->i_size; 371 } 372 if (de->attr & ATTR_SYS) { 373 if (sbi->options.sys_immutable) 374 inode->i_flags |= S_IMMUTABLE; 375 } 376 MSDOS_I(inode)->i_attrs = de->attr & ATTR_UNUSED; 377 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 378 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 379 inode->i_mtime.tv_sec = 380 date_dos2unix(le16_to_cpu(de->time), le16_to_cpu(de->date)); 381 inode->i_mtime.tv_nsec = 0; 382 if (sbi->options.isvfat) { 383 int secs = de->ctime_cs / 100; 384 int csecs = de->ctime_cs % 100; 385 inode->i_ctime.tv_sec = 386 date_dos2unix(le16_to_cpu(de->ctime), 387 le16_to_cpu(de->cdate)) + secs; 388 inode->i_ctime.tv_nsec = csecs * 10000000; 389 inode->i_atime.tv_sec = 390 date_dos2unix(0, le16_to_cpu(de->adate)); 391 inode->i_atime.tv_nsec = 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); 431 432 if (!is_bad_inode(inode)) { 433 inode->i_size = 0; 434 fat_truncate(inode); 435 } 436 clear_inode(inode); 437 } 438 439 static void fat_clear_inode(struct inode *inode) 440 { 441 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 442 443 if (is_bad_inode(inode)) 444 return; 445 lock_kernel(); 446 spin_lock(&sbi->inode_hash_lock); 447 fat_cache_inval_inode(inode); 448 hlist_del_init(&MSDOS_I(inode)->i_fat_hash); 449 spin_unlock(&sbi->inode_hash_lock); 450 unlock_kernel(); 451 } 452 453 static void fat_write_super(struct super_block *sb) 454 { 455 sb->s_dirt = 0; 456 457 if (!(sb->s_flags & MS_RDONLY)) 458 fat_clusters_flush(sb); 459 } 460 461 static void fat_put_super(struct super_block *sb) 462 { 463 struct msdos_sb_info *sbi = MSDOS_SB(sb); 464 465 if (sbi->nls_disk) { 466 unload_nls(sbi->nls_disk); 467 sbi->nls_disk = NULL; 468 sbi->options.codepage = fat_default_codepage; 469 } 470 if (sbi->nls_io) { 471 unload_nls(sbi->nls_io); 472 sbi->nls_io = NULL; 473 } 474 if (sbi->options.iocharset != fat_default_iocharset) { 475 kfree(sbi->options.iocharset); 476 sbi->options.iocharset = fat_default_iocharset; 477 } 478 479 sb->s_fs_info = NULL; 480 kfree(sbi); 481 } 482 483 static struct kmem_cache *fat_inode_cachep; 484 485 static struct inode *fat_alloc_inode(struct super_block *sb) 486 { 487 struct msdos_inode_info *ei; 488 ei = kmem_cache_alloc(fat_inode_cachep, GFP_KERNEL); 489 if (!ei) 490 return NULL; 491 return &ei->vfs_inode; 492 } 493 494 static void fat_destroy_inode(struct inode *inode) 495 { 496 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode)); 497 } 498 499 static void init_once(void * foo, struct kmem_cache * cachep, unsigned long flags) 500 { 501 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo; 502 503 if (flags & SLAB_CTOR_CONSTRUCTOR) { 504 spin_lock_init(&ei->cache_lru_lock); 505 ei->nr_caches = 0; 506 ei->cache_valid_id = FAT_CACHE_VALID + 1; 507 INIT_LIST_HEAD(&ei->cache_lru); 508 INIT_HLIST_NODE(&ei->i_fat_hash); 509 inode_init_once(&ei->vfs_inode); 510 } 511 } 512 513 static int __init fat_init_inodecache(void) 514 { 515 fat_inode_cachep = kmem_cache_create("fat_inode_cache", 516 sizeof(struct msdos_inode_info), 517 0, (SLAB_RECLAIM_ACCOUNT| 518 SLAB_MEM_SPREAD), 519 init_once, NULL); 520 if (fat_inode_cachep == NULL) 521 return -ENOMEM; 522 return 0; 523 } 524 525 static void __exit fat_destroy_inodecache(void) 526 { 527 kmem_cache_destroy(fat_inode_cachep); 528 } 529 530 static int fat_remount(struct super_block *sb, int *flags, char *data) 531 { 532 struct msdos_sb_info *sbi = MSDOS_SB(sb); 533 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME); 534 return 0; 535 } 536 537 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf) 538 { 539 struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb); 540 541 /* If the count of free cluster is still unknown, counts it here. */ 542 if (sbi->free_clusters == -1) { 543 int err = fat_count_free_clusters(dentry->d_sb); 544 if (err) 545 return err; 546 } 547 548 buf->f_type = dentry->d_sb->s_magic; 549 buf->f_bsize = sbi->cluster_size; 550 buf->f_blocks = sbi->max_cluster - FAT_START_ENT; 551 buf->f_bfree = sbi->free_clusters; 552 buf->f_bavail = sbi->free_clusters; 553 buf->f_namelen = sbi->options.isvfat ? 260 : 12; 554 555 return 0; 556 } 557 558 static int fat_write_inode(struct inode *inode, int wait) 559 { 560 struct super_block *sb = inode->i_sb; 561 struct msdos_sb_info *sbi = MSDOS_SB(sb); 562 struct buffer_head *bh; 563 struct msdos_dir_entry *raw_entry; 564 loff_t i_pos; 565 int err = 0; 566 567 retry: 568 i_pos = MSDOS_I(inode)->i_pos; 569 if (inode->i_ino == MSDOS_ROOT_INO || !i_pos) 570 return 0; 571 572 lock_kernel(); 573 bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits); 574 if (!bh) { 575 printk(KERN_ERR "FAT: unable to read inode block " 576 "for updating (i_pos %lld)\n", i_pos); 577 err = -EIO; 578 goto out; 579 } 580 spin_lock(&sbi->inode_hash_lock); 581 if (i_pos != MSDOS_I(inode)->i_pos) { 582 spin_unlock(&sbi->inode_hash_lock); 583 brelse(bh); 584 unlock_kernel(); 585 goto retry; 586 } 587 588 raw_entry = &((struct msdos_dir_entry *) (bh->b_data)) 589 [i_pos & (sbi->dir_per_block - 1)]; 590 if (S_ISDIR(inode->i_mode)) 591 raw_entry->size = 0; 592 else 593 raw_entry->size = cpu_to_le32(inode->i_size); 594 raw_entry->attr = fat_attr(inode); 595 raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart); 596 raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16); 597 fat_date_unix2dos(inode->i_mtime.tv_sec, &raw_entry->time, &raw_entry->date); 598 if (sbi->options.isvfat) { 599 __le16 atime; 600 fat_date_unix2dos(inode->i_ctime.tv_sec,&raw_entry->ctime,&raw_entry->cdate); 601 fat_date_unix2dos(inode->i_atime.tv_sec,&atime,&raw_entry->adate); 602 raw_entry->ctime_cs = (inode->i_ctime.tv_sec & 1) * 100 + 603 inode->i_ctime.tv_nsec / 10000000; 604 } 605 spin_unlock(&sbi->inode_hash_lock); 606 mark_buffer_dirty(bh); 607 if (wait) 608 err = sync_dirty_buffer(bh); 609 brelse(bh); 610 out: 611 unlock_kernel(); 612 return err; 613 } 614 615 int fat_sync_inode(struct inode *inode) 616 { 617 return fat_write_inode(inode, 1); 618 } 619 620 EXPORT_SYMBOL_GPL(fat_sync_inode); 621 622 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt); 623 static const struct super_operations fat_sops = { 624 .alloc_inode = fat_alloc_inode, 625 .destroy_inode = fat_destroy_inode, 626 .write_inode = fat_write_inode, 627 .delete_inode = fat_delete_inode, 628 .put_super = fat_put_super, 629 .write_super = fat_write_super, 630 .statfs = fat_statfs, 631 .clear_inode = fat_clear_inode, 632 .remount_fs = fat_remount, 633 634 .read_inode = make_bad_inode, 635 636 .show_options = fat_show_options, 637 }; 638 639 /* 640 * a FAT file handle with fhtype 3 is 641 * 0/ i_ino - for fast, reliable lookup if still in the cache 642 * 1/ i_generation - to see if i_ino is still valid 643 * bit 0 == 0 iff directory 644 * 2/ i_pos(8-39) - if ino has changed, but still in cache 645 * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos 646 * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc 647 * 648 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum 649 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits 650 * of i_logstart is used to store the directory entry offset. 651 */ 652 653 static struct dentry * 654 fat_decode_fh(struct super_block *sb, __u32 *fh, int len, int fhtype, 655 int (*acceptable)(void *context, struct dentry *de), 656 void *context) 657 { 658 if (fhtype != 3) 659 return ERR_PTR(-ESTALE); 660 if (len < 5) 661 return ERR_PTR(-ESTALE); 662 663 return sb->s_export_op->find_exported_dentry(sb, fh, NULL, acceptable, context); 664 } 665 666 static struct dentry *fat_get_dentry(struct super_block *sb, void *inump) 667 { 668 struct inode *inode = NULL; 669 struct dentry *result; 670 __u32 *fh = inump; 671 672 inode = iget(sb, fh[0]); 673 if (!inode || is_bad_inode(inode) || inode->i_generation != fh[1]) { 674 if (inode) 675 iput(inode); 676 inode = NULL; 677 } 678 if (!inode) { 679 loff_t i_pos; 680 int i_logstart = fh[3] & 0x0fffffff; 681 682 i_pos = (loff_t)fh[2] << 8; 683 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28); 684 685 /* try 2 - see if i_pos is in F-d-c 686 * require i_logstart to be the same 687 * Will fail if you truncate and then re-write 688 */ 689 690 inode = fat_iget(sb, i_pos); 691 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) { 692 iput(inode); 693 inode = NULL; 694 } 695 } 696 if (!inode) { 697 /* For now, do nothing 698 * What we could do is: 699 * follow the file starting at fh[4], and record 700 * the ".." entry, and the name of the fh[2] entry. 701 * The follow the ".." file finding the next step up. 702 * This way we build a path to the root of 703 * the tree. If this works, we lookup the path and so 704 * get this inode into the cache. 705 * Finally try the fat_iget lookup again 706 * If that fails, then weare totally out of luck 707 * But all that is for another day 708 */ 709 } 710 if (!inode) 711 return ERR_PTR(-ESTALE); 712 713 714 /* now to find a dentry. 715 * If possible, get a well-connected one 716 */ 717 result = d_alloc_anon(inode); 718 if (result == NULL) { 719 iput(inode); 720 return ERR_PTR(-ENOMEM); 721 } 722 result->d_op = sb->s_root->d_op; 723 return result; 724 } 725 726 static int 727 fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable) 728 { 729 int len = *lenp; 730 struct inode *inode = de->d_inode; 731 u32 ipos_h, ipos_m, ipos_l; 732 733 if (len < 5) 734 return 255; /* no room */ 735 736 ipos_h = MSDOS_I(inode)->i_pos >> 8; 737 ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24; 738 ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28; 739 *lenp = 5; 740 fh[0] = inode->i_ino; 741 fh[1] = inode->i_generation; 742 fh[2] = ipos_h; 743 fh[3] = ipos_m | MSDOS_I(inode)->i_logstart; 744 spin_lock(&de->d_lock); 745 fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart; 746 spin_unlock(&de->d_lock); 747 return 3; 748 } 749 750 static struct dentry *fat_get_parent(struct dentry *child) 751 { 752 struct buffer_head *bh; 753 struct msdos_dir_entry *de; 754 loff_t i_pos; 755 struct dentry *parent; 756 struct inode *inode; 757 int err; 758 759 lock_kernel(); 760 761 err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos); 762 if (err) { 763 parent = ERR_PTR(err); 764 goto out; 765 } 766 inode = fat_build_inode(child->d_sb, de, i_pos); 767 brelse(bh); 768 if (IS_ERR(inode)) { 769 parent = ERR_PTR(PTR_ERR(inode)); 770 goto out; 771 } 772 parent = d_alloc_anon(inode); 773 if (!parent) { 774 iput(inode); 775 parent = ERR_PTR(-ENOMEM); 776 } 777 out: 778 unlock_kernel(); 779 780 return parent; 781 } 782 783 static struct export_operations fat_export_ops = { 784 .decode_fh = fat_decode_fh, 785 .encode_fh = fat_encode_fh, 786 .get_dentry = fat_get_dentry, 787 .get_parent = fat_get_parent, 788 }; 789 790 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt) 791 { 792 struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb); 793 struct fat_mount_options *opts = &sbi->options; 794 int isvfat = opts->isvfat; 795 796 if (opts->fs_uid != 0) 797 seq_printf(m, ",uid=%u", opts->fs_uid); 798 if (opts->fs_gid != 0) 799 seq_printf(m, ",gid=%u", opts->fs_gid); 800 seq_printf(m, ",fmask=%04o", opts->fs_fmask); 801 seq_printf(m, ",dmask=%04o", opts->fs_dmask); 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 } 849 850 return 0; 851 } 852 853 enum { 854 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid, 855 Opt_umask, Opt_dmask, Opt_fmask, Opt_codepage, Opt_usefree, Opt_nocase, 856 Opt_quiet, Opt_showexec, Opt_debug, Opt_immutable, 857 Opt_dots, Opt_nodots, 858 Opt_charset, Opt_shortname_lower, Opt_shortname_win95, 859 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes, 860 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes, 861 Opt_obsolate, Opt_flush, Opt_err, 862 }; 863 864 static match_table_t fat_tokens = { 865 {Opt_check_r, "check=relaxed"}, 866 {Opt_check_s, "check=strict"}, 867 {Opt_check_n, "check=normal"}, 868 {Opt_check_r, "check=r"}, 869 {Opt_check_s, "check=s"}, 870 {Opt_check_n, "check=n"}, 871 {Opt_uid, "uid=%u"}, 872 {Opt_gid, "gid=%u"}, 873 {Opt_umask, "umask=%o"}, 874 {Opt_dmask, "dmask=%o"}, 875 {Opt_fmask, "fmask=%o"}, 876 {Opt_codepage, "codepage=%u"}, 877 {Opt_usefree, "usefree"}, 878 {Opt_nocase, "nocase"}, 879 {Opt_quiet, "quiet"}, 880 {Opt_showexec, "showexec"}, 881 {Opt_debug, "debug"}, 882 {Opt_immutable, "sys_immutable"}, 883 {Opt_obsolate, "conv=binary"}, 884 {Opt_obsolate, "conv=text"}, 885 {Opt_obsolate, "conv=auto"}, 886 {Opt_obsolate, "conv=b"}, 887 {Opt_obsolate, "conv=t"}, 888 {Opt_obsolate, "conv=a"}, 889 {Opt_obsolate, "fat=%u"}, 890 {Opt_obsolate, "blocksize=%u"}, 891 {Opt_obsolate, "cvf_format=%20s"}, 892 {Opt_obsolate, "cvf_options=%100s"}, 893 {Opt_obsolate, "posix"}, 894 {Opt_flush, "flush"}, 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->usefree = 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_usefree: 986 opts->usefree = 1; 987 break; 988 case Opt_nocase: 989 if (!is_vfat) 990 opts->nocase = 1; 991 else { 992 /* for backward compatibility */ 993 opts->shortname = VFAT_SFN_DISPLAY_WIN95 994 | VFAT_SFN_CREATE_WIN95; 995 } 996 break; 997 case Opt_quiet: 998 opts->quiet = 1; 999 break; 1000 case Opt_showexec: 1001 opts->showexec = 1; 1002 break; 1003 case Opt_debug: 1004 *debug = 1; 1005 break; 1006 case Opt_immutable: 1007 opts->sys_immutable = 1; 1008 break; 1009 case Opt_uid: 1010 if (match_int(&args[0], &option)) 1011 return 0; 1012 opts->fs_uid = option; 1013 break; 1014 case Opt_gid: 1015 if (match_int(&args[0], &option)) 1016 return 0; 1017 opts->fs_gid = option; 1018 break; 1019 case Opt_umask: 1020 if (match_octal(&args[0], &option)) 1021 return 0; 1022 opts->fs_fmask = opts->fs_dmask = option; 1023 break; 1024 case Opt_dmask: 1025 if (match_octal(&args[0], &option)) 1026 return 0; 1027 opts->fs_dmask = option; 1028 break; 1029 case Opt_fmask: 1030 if (match_octal(&args[0], &option)) 1031 return 0; 1032 opts->fs_fmask = option; 1033 break; 1034 case Opt_codepage: 1035 if (match_int(&args[0], &option)) 1036 return 0; 1037 opts->codepage = option; 1038 break; 1039 case Opt_flush: 1040 opts->flush = 1; 1041 break; 1042 1043 /* msdos specific */ 1044 case Opt_dots: 1045 opts->dotsOK = 1; 1046 break; 1047 case Opt_nodots: 1048 opts->dotsOK = 0; 1049 break; 1050 1051 /* vfat specific */ 1052 case Opt_charset: 1053 if (opts->iocharset != fat_default_iocharset) 1054 kfree(opts->iocharset); 1055 iocharset = match_strdup(&args[0]); 1056 if (!iocharset) 1057 return -ENOMEM; 1058 opts->iocharset = iocharset; 1059 break; 1060 case Opt_shortname_lower: 1061 opts->shortname = VFAT_SFN_DISPLAY_LOWER 1062 | VFAT_SFN_CREATE_WIN95; 1063 break; 1064 case Opt_shortname_win95: 1065 opts->shortname = VFAT_SFN_DISPLAY_WIN95 1066 | VFAT_SFN_CREATE_WIN95; 1067 break; 1068 case Opt_shortname_winnt: 1069 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1070 | VFAT_SFN_CREATE_WINNT; 1071 break; 1072 case Opt_shortname_mixed: 1073 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1074 | VFAT_SFN_CREATE_WIN95; 1075 break; 1076 case Opt_utf8_no: /* 0 or no or false */ 1077 opts->utf8 = 0; 1078 break; 1079 case Opt_utf8_yes: /* empty or 1 or yes or true */ 1080 opts->utf8 = 1; 1081 break; 1082 case Opt_uni_xl_no: /* 0 or no or false */ 1083 opts->unicode_xlate = 0; 1084 break; 1085 case Opt_uni_xl_yes: /* empty or 1 or yes or true */ 1086 opts->unicode_xlate = 1; 1087 break; 1088 case Opt_nonumtail_no: /* 0 or no or false */ 1089 opts->numtail = 1; /* negated option */ 1090 break; 1091 case Opt_nonumtail_yes: /* empty or 1 or yes or true */ 1092 opts->numtail = 0; /* negated option */ 1093 break; 1094 1095 /* obsolete mount options */ 1096 case Opt_obsolate: 1097 printk(KERN_INFO "FAT: \"%s\" option is obsolete, " 1098 "not supported now\n", p); 1099 break; 1100 /* unknown option */ 1101 default: 1102 if (!silent) { 1103 printk(KERN_ERR 1104 "FAT: Unrecognized mount option \"%s\" " 1105 "or missing value\n", p); 1106 } 1107 return -EINVAL; 1108 } 1109 } 1110 /* UTF-8 doesn't provide FAT semantics */ 1111 if (!strcmp(opts->iocharset, "utf8")) { 1112 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset" 1113 " for FAT filesystems, filesystem will be case sensitive!\n"); 1114 } 1115 1116 if (opts->unicode_xlate) 1117 opts->utf8 = 0; 1118 1119 return 0; 1120 } 1121 1122 static int fat_read_root(struct inode *inode) 1123 { 1124 struct super_block *sb = inode->i_sb; 1125 struct msdos_sb_info *sbi = MSDOS_SB(sb); 1126 int error; 1127 1128 MSDOS_I(inode)->i_pos = 0; 1129 inode->i_uid = sbi->options.fs_uid; 1130 inode->i_gid = sbi->options.fs_gid; 1131 inode->i_version++; 1132 inode->i_generation = 0; 1133 inode->i_mode = (S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR; 1134 inode->i_op = sbi->dir_ops; 1135 inode->i_fop = &fat_dir_operations; 1136 if (sbi->fat_bits == 32) { 1137 MSDOS_I(inode)->i_start = sbi->root_cluster; 1138 error = fat_calc_dir_size(inode); 1139 if (error < 0) 1140 return error; 1141 } else { 1142 MSDOS_I(inode)->i_start = 0; 1143 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry); 1144 } 1145 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 1146 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 1147 MSDOS_I(inode)->i_logstart = 0; 1148 MSDOS_I(inode)->mmu_private = inode->i_size; 1149 1150 MSDOS_I(inode)->i_attrs = ATTR_NONE; 1151 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0; 1152 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0; 1153 inode->i_nlink = fat_subdirs(inode)+2; 1154 1155 return 0; 1156 } 1157 1158 /* 1159 * Read the super block of an MS-DOS FS. 1160 */ 1161 int fat_fill_super(struct super_block *sb, void *data, int silent, 1162 const struct inode_operations *fs_dir_inode_ops, int isvfat) 1163 { 1164 struct inode *root_inode = NULL; 1165 struct buffer_head *bh; 1166 struct fat_boot_sector *b; 1167 struct msdos_sb_info *sbi; 1168 u16 logical_sector_size; 1169 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors; 1170 int debug; 1171 unsigned int media; 1172 long error; 1173 char buf[50]; 1174 1175 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL); 1176 if (!sbi) 1177 return -ENOMEM; 1178 sb->s_fs_info = sbi; 1179 1180 sb->s_flags |= MS_NODIRATIME; 1181 sb->s_magic = MSDOS_SUPER_MAGIC; 1182 sb->s_op = &fat_sops; 1183 sb->s_export_op = &fat_export_ops; 1184 sbi->dir_ops = fs_dir_inode_ops; 1185 1186 error = parse_options(data, isvfat, silent, &debug, &sbi->options); 1187 if (error) 1188 goto out_fail; 1189 1190 error = -EIO; 1191 sb_min_blocksize(sb, 512); 1192 bh = sb_bread(sb, 0); 1193 if (bh == NULL) { 1194 printk(KERN_ERR "FAT: unable to read boot sector\n"); 1195 goto out_fail; 1196 } 1197 1198 b = (struct fat_boot_sector *) bh->b_data; 1199 if (!b->reserved) { 1200 if (!silent) 1201 printk(KERN_ERR "FAT: bogus number of reserved sectors\n"); 1202 brelse(bh); 1203 goto out_invalid; 1204 } 1205 if (!b->fats) { 1206 if (!silent) 1207 printk(KERN_ERR "FAT: bogus number of FAT structure\n"); 1208 brelse(bh); 1209 goto out_invalid; 1210 } 1211 1212 /* 1213 * Earlier we checked here that b->secs_track and b->head are nonzero, 1214 * but it turns out valid FAT filesystems can have zero there. 1215 */ 1216 1217 media = b->media; 1218 if (!FAT_VALID_MEDIA(media)) { 1219 if (!silent) 1220 printk(KERN_ERR "FAT: invalid media value (0x%02x)\n", 1221 media); 1222 brelse(bh); 1223 goto out_invalid; 1224 } 1225 logical_sector_size = 1226 le16_to_cpu(get_unaligned((__le16 *)&b->sector_size)); 1227 if (!is_power_of_2(logical_sector_size) 1228 || (logical_sector_size < 512) 1229 || (PAGE_CACHE_SIZE < logical_sector_size)) { 1230 if (!silent) 1231 printk(KERN_ERR "FAT: bogus logical sector size %u\n", 1232 logical_sector_size); 1233 brelse(bh); 1234 goto out_invalid; 1235 } 1236 sbi->sec_per_clus = b->sec_per_clus; 1237 if (!is_power_of_2(sbi->sec_per_clus)) { 1238 if (!silent) 1239 printk(KERN_ERR "FAT: bogus sectors per cluster %u\n", 1240 sbi->sec_per_clus); 1241 brelse(bh); 1242 goto out_invalid; 1243 } 1244 1245 if (logical_sector_size < sb->s_blocksize) { 1246 printk(KERN_ERR "FAT: logical sector size too small for device" 1247 " (logical sector size = %u)\n", logical_sector_size); 1248 brelse(bh); 1249 goto out_fail; 1250 } 1251 if (logical_sector_size > sb->s_blocksize) { 1252 brelse(bh); 1253 1254 if (!sb_set_blocksize(sb, logical_sector_size)) { 1255 printk(KERN_ERR "FAT: unable to set blocksize %u\n", 1256 logical_sector_size); 1257 goto out_fail; 1258 } 1259 bh = sb_bread(sb, 0); 1260 if (bh == NULL) { 1261 printk(KERN_ERR "FAT: unable to read boot sector" 1262 " (logical sector size = %lu)\n", 1263 sb->s_blocksize); 1264 goto out_fail; 1265 } 1266 b = (struct fat_boot_sector *) bh->b_data; 1267 } 1268 1269 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus; 1270 sbi->cluster_bits = ffs(sbi->cluster_size) - 1; 1271 sbi->fats = b->fats; 1272 sbi->fat_bits = 0; /* Don't know yet */ 1273 sbi->fat_start = le16_to_cpu(b->reserved); 1274 sbi->fat_length = le16_to_cpu(b->fat_length); 1275 sbi->root_cluster = 0; 1276 sbi->free_clusters = -1; /* Don't know yet */ 1277 sbi->prev_free = FAT_START_ENT; 1278 1279 if (!sbi->fat_length && b->fat32_length) { 1280 struct fat_boot_fsinfo *fsinfo; 1281 struct buffer_head *fsinfo_bh; 1282 1283 /* Must be FAT32 */ 1284 sbi->fat_bits = 32; 1285 sbi->fat_length = le32_to_cpu(b->fat32_length); 1286 sbi->root_cluster = le32_to_cpu(b->root_cluster); 1287 1288 sb->s_maxbytes = 0xffffffff; 1289 1290 /* MC - if info_sector is 0, don't multiply by 0 */ 1291 sbi->fsinfo_sector = le16_to_cpu(b->info_sector); 1292 if (sbi->fsinfo_sector == 0) 1293 sbi->fsinfo_sector = 1; 1294 1295 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector); 1296 if (fsinfo_bh == NULL) { 1297 printk(KERN_ERR "FAT: bread failed, FSINFO block" 1298 " (sector = %lu)\n", sbi->fsinfo_sector); 1299 brelse(bh); 1300 goto out_fail; 1301 } 1302 1303 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data; 1304 if (!IS_FSINFO(fsinfo)) { 1305 printk(KERN_WARNING 1306 "FAT: Did not find valid FSINFO signature.\n" 1307 " Found signature1 0x%08x signature2 0x%08x" 1308 " (sector = %lu)\n", 1309 le32_to_cpu(fsinfo->signature1), 1310 le32_to_cpu(fsinfo->signature2), 1311 sbi->fsinfo_sector); 1312 } else { 1313 if (sbi->options.usefree) 1314 sbi->free_clusters = 1315 le32_to_cpu(fsinfo->free_clusters); 1316 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster); 1317 } 1318 1319 brelse(fsinfo_bh); 1320 } 1321 1322 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry); 1323 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1; 1324 1325 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length; 1326 sbi->dir_entries = 1327 le16_to_cpu(get_unaligned((__le16 *)&b->dir_entries)); 1328 if (sbi->dir_entries & (sbi->dir_per_block - 1)) { 1329 if (!silent) 1330 printk(KERN_ERR "FAT: bogus directroy-entries per block" 1331 " (%u)\n", sbi->dir_entries); 1332 brelse(bh); 1333 goto out_invalid; 1334 } 1335 1336 rootdir_sectors = sbi->dir_entries 1337 * sizeof(struct msdos_dir_entry) / sb->s_blocksize; 1338 sbi->data_start = sbi->dir_start + rootdir_sectors; 1339 total_sectors = le16_to_cpu(get_unaligned((__le16 *)&b->sectors)); 1340 if (total_sectors == 0) 1341 total_sectors = le32_to_cpu(b->total_sect); 1342 1343 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus; 1344 1345 if (sbi->fat_bits != 32) 1346 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12; 1347 1348 /* check that FAT table does not overflow */ 1349 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits; 1350 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT); 1351 if (total_clusters > MAX_FAT(sb)) { 1352 if (!silent) 1353 printk(KERN_ERR "FAT: count of clusters too big (%u)\n", 1354 total_clusters); 1355 brelse(bh); 1356 goto out_invalid; 1357 } 1358 1359 sbi->max_cluster = total_clusters + FAT_START_ENT; 1360 /* check the free_clusters, it's not necessarily correct */ 1361 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters) 1362 sbi->free_clusters = -1; 1363 /* check the prev_free, it's not necessarily correct */ 1364 sbi->prev_free %= sbi->max_cluster; 1365 if (sbi->prev_free < FAT_START_ENT) 1366 sbi->prev_free = FAT_START_ENT; 1367 1368 brelse(bh); 1369 1370 /* set up enough so that it can read an inode */ 1371 fat_hash_init(sb); 1372 fat_ent_access_init(sb); 1373 1374 /* 1375 * The low byte of FAT's first entry must have same value with 1376 * media-field. But in real world, too many devices is 1377 * writing wrong value. So, removed that validity check. 1378 * 1379 * if (FAT_FIRST_ENT(sb, media) != first) 1380 */ 1381 1382 error = -EINVAL; 1383 sprintf(buf, "cp%d", sbi->options.codepage); 1384 sbi->nls_disk = load_nls(buf); 1385 if (!sbi->nls_disk) { 1386 printk(KERN_ERR "FAT: codepage %s not found\n", buf); 1387 goto out_fail; 1388 } 1389 1390 /* FIXME: utf8 is using iocharset for upper/lower conversion */ 1391 if (sbi->options.isvfat) { 1392 sbi->nls_io = load_nls(sbi->options.iocharset); 1393 if (!sbi->nls_io) { 1394 printk(KERN_ERR "FAT: IO charset %s not found\n", 1395 sbi->options.iocharset); 1396 goto out_fail; 1397 } 1398 } 1399 1400 error = -ENOMEM; 1401 root_inode = new_inode(sb); 1402 if (!root_inode) 1403 goto out_fail; 1404 root_inode->i_ino = MSDOS_ROOT_INO; 1405 root_inode->i_version = 1; 1406 error = fat_read_root(root_inode); 1407 if (error < 0) 1408 goto out_fail; 1409 error = -ENOMEM; 1410 insert_inode_hash(root_inode); 1411 sb->s_root = d_alloc_root(root_inode); 1412 if (!sb->s_root) { 1413 printk(KERN_ERR "FAT: get root inode failed\n"); 1414 goto out_fail; 1415 } 1416 1417 return 0; 1418 1419 out_invalid: 1420 error = -EINVAL; 1421 if (!silent) 1422 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem" 1423 " on dev %s.\n", sb->s_id); 1424 1425 out_fail: 1426 if (root_inode) 1427 iput(root_inode); 1428 if (sbi->nls_io) 1429 unload_nls(sbi->nls_io); 1430 if (sbi->nls_disk) 1431 unload_nls(sbi->nls_disk); 1432 if (sbi->options.iocharset != fat_default_iocharset) 1433 kfree(sbi->options.iocharset); 1434 sb->s_fs_info = NULL; 1435 kfree(sbi); 1436 return error; 1437 } 1438 1439 EXPORT_SYMBOL_GPL(fat_fill_super); 1440 1441 /* 1442 * helper function for fat_flush_inodes. This writes both the inode 1443 * and the file data blocks, waiting for in flight data blocks before 1444 * the start of the call. It does not wait for any io started 1445 * during the call 1446 */ 1447 static int writeback_inode(struct inode *inode) 1448 { 1449 1450 int ret; 1451 struct address_space *mapping = inode->i_mapping; 1452 struct writeback_control wbc = { 1453 .sync_mode = WB_SYNC_NONE, 1454 .nr_to_write = 0, 1455 }; 1456 /* if we used WB_SYNC_ALL, sync_inode waits for the io for the 1457 * inode to finish. So WB_SYNC_NONE is sent down to sync_inode 1458 * and filemap_fdatawrite is used for the data blocks 1459 */ 1460 ret = sync_inode(inode, &wbc); 1461 if (!ret) 1462 ret = filemap_fdatawrite(mapping); 1463 return ret; 1464 } 1465 1466 /* 1467 * write data and metadata corresponding to i1 and i2. The io is 1468 * started but we do not wait for any of it to finish. 1469 * 1470 * filemap_flush is used for the block device, so if there is a dirty 1471 * page for a block already in flight, we will not wait and start the 1472 * io over again 1473 */ 1474 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2) 1475 { 1476 int ret = 0; 1477 if (!MSDOS_SB(sb)->options.flush) 1478 return 0; 1479 if (i1) 1480 ret = writeback_inode(i1); 1481 if (!ret && i2) 1482 ret = writeback_inode(i2); 1483 if (!ret) { 1484 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping; 1485 ret = filemap_flush(mapping); 1486 } 1487 return ret; 1488 } 1489 EXPORT_SYMBOL_GPL(fat_flush_inodes); 1490 1491 static int __init init_fat_fs(void) 1492 { 1493 int err; 1494 1495 err = fat_cache_init(); 1496 if (err) 1497 return err; 1498 1499 err = fat_init_inodecache(); 1500 if (err) 1501 goto failed; 1502 1503 return 0; 1504 1505 failed: 1506 fat_cache_destroy(); 1507 return err; 1508 } 1509 1510 static void __exit exit_fat_fs(void) 1511 { 1512 fat_cache_destroy(); 1513 fat_destroy_inodecache(); 1514 } 1515 1516 module_init(init_fat_fs) 1517 module_exit(exit_fat_fs) 1518 1519 MODULE_LICENSE("GPL"); 1520