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 <asm/unaligned.h> 29 30 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET 31 /* if user don't select VFAT, this is undefined. */ 32 #define CONFIG_FAT_DEFAULT_IOCHARSET "" 33 #endif 34 35 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE; 36 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET; 37 38 39 static int fat_add_cluster(struct inode *inode) 40 { 41 int err, cluster; 42 43 err = fat_alloc_clusters(inode, &cluster, 1); 44 if (err) 45 return err; 46 /* FIXME: this cluster should be added after data of this 47 * cluster is writed */ 48 err = fat_chain_add(inode, cluster, 1); 49 if (err) 50 fat_free_clusters(inode, cluster); 51 return err; 52 } 53 54 static inline int __fat_get_block(struct inode *inode, sector_t iblock, 55 unsigned long *max_blocks, 56 struct buffer_head *bh_result, int create) 57 { 58 struct super_block *sb = inode->i_sb; 59 struct msdos_sb_info *sbi = MSDOS_SB(sb); 60 unsigned long mapped_blocks; 61 sector_t phys; 62 int err, offset; 63 64 err = fat_bmap(inode, iblock, &phys, &mapped_blocks); 65 if (err) 66 return err; 67 if (phys) { 68 map_bh(bh_result, sb, phys); 69 *max_blocks = min(mapped_blocks, *max_blocks); 70 return 0; 71 } 72 if (!create) 73 return 0; 74 75 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) { 76 fat_fs_panic(sb, "corrupted file size (i_pos %lld, %lld)", 77 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private); 78 return -EIO; 79 } 80 81 offset = (unsigned long)iblock & (sbi->sec_per_clus - 1); 82 if (!offset) { 83 /* TODO: multiple cluster allocation would be desirable. */ 84 err = fat_add_cluster(inode); 85 if (err) 86 return err; 87 } 88 /* available blocks on this cluster */ 89 mapped_blocks = sbi->sec_per_clus - offset; 90 91 *max_blocks = min(mapped_blocks, *max_blocks); 92 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits; 93 94 err = fat_bmap(inode, iblock, &phys, &mapped_blocks); 95 if (err) 96 return err; 97 98 BUG_ON(!phys); 99 BUG_ON(*max_blocks != mapped_blocks); 100 set_buffer_new(bh_result); 101 map_bh(bh_result, sb, phys); 102 103 return 0; 104 } 105 106 static int fat_get_block(struct inode *inode, sector_t iblock, 107 struct buffer_head *bh_result, int create) 108 { 109 struct super_block *sb = inode->i_sb; 110 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits; 111 int err; 112 113 err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create); 114 if (err) 115 return err; 116 bh_result->b_size = max_blocks << sb->s_blocksize_bits; 117 return 0; 118 } 119 120 static int fat_writepage(struct page *page, struct writeback_control *wbc) 121 { 122 return block_write_full_page(page, fat_get_block, wbc); 123 } 124 125 static int fat_writepages(struct address_space *mapping, 126 struct writeback_control *wbc) 127 { 128 return mpage_writepages(mapping, wbc, fat_get_block); 129 } 130 131 static int fat_readpage(struct file *file, struct page *page) 132 { 133 return mpage_readpage(page, fat_get_block); 134 } 135 136 static int fat_readpages(struct file *file, struct address_space *mapping, 137 struct list_head *pages, unsigned nr_pages) 138 { 139 return mpage_readpages(mapping, pages, nr_pages, fat_get_block); 140 } 141 142 static int fat_prepare_write(struct file *file, struct page *page, 143 unsigned from, unsigned to) 144 { 145 return cont_prepare_write(page, from, to, fat_get_block, 146 &MSDOS_I(page->mapping->host)->mmu_private); 147 } 148 149 static int fat_commit_write(struct file *file, struct page *page, 150 unsigned from, unsigned to) 151 { 152 struct inode *inode = page->mapping->host; 153 int err = generic_commit_write(file, page, from, to); 154 if (!err && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) { 155 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC; 156 MSDOS_I(inode)->i_attrs |= ATTR_ARCH; 157 mark_inode_dirty(inode); 158 } 159 return err; 160 } 161 162 static ssize_t fat_direct_IO(int rw, struct kiocb *iocb, 163 const struct iovec *iov, 164 loff_t offset, unsigned long nr_segs) 165 { 166 struct file *file = iocb->ki_filp; 167 struct inode *inode = file->f_mapping->host; 168 169 if (rw == WRITE) { 170 /* 171 * FIXME: blockdev_direct_IO() doesn't use ->prepare_write(), 172 * so we need to update the ->mmu_private to block boundary. 173 * 174 * But we must fill the remaining area or hole by nul for 175 * updating ->mmu_private. 176 * 177 * Return 0, and fallback to normal buffered write. 178 */ 179 loff_t size = offset + iov_length(iov, nr_segs); 180 if (MSDOS_I(inode)->mmu_private < size) 181 return 0; 182 } 183 184 /* 185 * FAT need to use the DIO_LOCKING for avoiding the race 186 * condition of fat_get_block() and ->truncate(). 187 */ 188 return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov, 189 offset, nr_segs, fat_get_block, NULL); 190 } 191 192 static sector_t _fat_bmap(struct address_space *mapping, sector_t block) 193 { 194 return generic_block_bmap(mapping, block, fat_get_block); 195 } 196 197 static const struct address_space_operations fat_aops = { 198 .readpage = fat_readpage, 199 .readpages = fat_readpages, 200 .writepage = fat_writepage, 201 .writepages = fat_writepages, 202 .sync_page = block_sync_page, 203 .prepare_write = fat_prepare_write, 204 .commit_write = fat_commit_write, 205 .direct_IO = fat_direct_IO, 206 .bmap = _fat_bmap 207 }; 208 209 /* 210 * New FAT inode stuff. We do the following: 211 * a) i_ino is constant and has nothing with on-disk location. 212 * b) FAT manages its own cache of directory entries. 213 * c) *This* cache is indexed by on-disk location. 214 * d) inode has an associated directory entry, all right, but 215 * it may be unhashed. 216 * e) currently entries are stored within struct inode. That should 217 * change. 218 * f) we deal with races in the following way: 219 * 1. readdir() and lookup() do FAT-dir-cache lookup. 220 * 2. rename() unhashes the F-d-c entry and rehashes it in 221 * a new place. 222 * 3. unlink() and rmdir() unhash F-d-c entry. 223 * 4. fat_write_inode() checks whether the thing is unhashed. 224 * If it is we silently return. If it isn't we do bread(), 225 * check if the location is still valid and retry if it 226 * isn't. Otherwise we do changes. 227 * 5. Spinlock is used to protect hash/unhash/location check/lookup 228 * 6. fat_clear_inode() unhashes the F-d-c entry. 229 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry 230 * and consider negative result as cache miss. 231 */ 232 233 static void fat_hash_init(struct super_block *sb) 234 { 235 struct msdos_sb_info *sbi = MSDOS_SB(sb); 236 int i; 237 238 spin_lock_init(&sbi->inode_hash_lock); 239 for (i = 0; i < FAT_HASH_SIZE; i++) 240 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]); 241 } 242 243 static inline unsigned long fat_hash(struct super_block *sb, loff_t i_pos) 244 { 245 unsigned long tmp = (unsigned long)i_pos | (unsigned long) sb; 246 tmp = tmp + (tmp >> FAT_HASH_BITS) + (tmp >> FAT_HASH_BITS * 2); 247 return tmp & FAT_HASH_MASK; 248 } 249 250 void fat_attach(struct inode *inode, loff_t i_pos) 251 { 252 struct super_block *sb = inode->i_sb; 253 struct msdos_sb_info *sbi = MSDOS_SB(sb); 254 255 spin_lock(&sbi->inode_hash_lock); 256 MSDOS_I(inode)->i_pos = i_pos; 257 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, 258 sbi->inode_hashtable + fat_hash(sb, i_pos)); 259 spin_unlock(&sbi->inode_hash_lock); 260 } 261 262 EXPORT_SYMBOL_GPL(fat_attach); 263 264 void fat_detach(struct inode *inode) 265 { 266 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 267 spin_lock(&sbi->inode_hash_lock); 268 MSDOS_I(inode)->i_pos = 0; 269 hlist_del_init(&MSDOS_I(inode)->i_fat_hash); 270 spin_unlock(&sbi->inode_hash_lock); 271 } 272 273 EXPORT_SYMBOL_GPL(fat_detach); 274 275 struct inode *fat_iget(struct super_block *sb, loff_t i_pos) 276 { 277 struct msdos_sb_info *sbi = MSDOS_SB(sb); 278 struct hlist_head *head = sbi->inode_hashtable + fat_hash(sb, i_pos); 279 struct hlist_node *_p; 280 struct msdos_inode_info *i; 281 struct inode *inode = NULL; 282 283 spin_lock(&sbi->inode_hash_lock); 284 hlist_for_each_entry(i, _p, head, i_fat_hash) { 285 BUG_ON(i->vfs_inode.i_sb != sb); 286 if (i->i_pos != i_pos) 287 continue; 288 inode = igrab(&i->vfs_inode); 289 if (inode) 290 break; 291 } 292 spin_unlock(&sbi->inode_hash_lock); 293 return inode; 294 } 295 296 static int is_exec(unsigned char *extension) 297 { 298 unsigned char *exe_extensions = "EXECOMBAT", *walk; 299 300 for (walk = exe_extensions; *walk; walk += 3) 301 if (!strncmp(extension, walk, 3)) 302 return 1; 303 return 0; 304 } 305 306 static int fat_calc_dir_size(struct inode *inode) 307 { 308 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 309 int ret, fclus, dclus; 310 311 inode->i_size = 0; 312 if (MSDOS_I(inode)->i_start == 0) 313 return 0; 314 315 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); 316 if (ret < 0) 317 return ret; 318 inode->i_size = (fclus + 1) << sbi->cluster_bits; 319 320 return 0; 321 } 322 323 /* doesn't deal with root inode */ 324 static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de) 325 { 326 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 327 int error; 328 329 MSDOS_I(inode)->i_pos = 0; 330 inode->i_uid = sbi->options.fs_uid; 331 inode->i_gid = sbi->options.fs_gid; 332 inode->i_version++; 333 inode->i_generation = get_seconds(); 334 335 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) { 336 inode->i_generation &= ~1; 337 inode->i_mode = MSDOS_MKMODE(de->attr, 338 S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR; 339 inode->i_op = sbi->dir_ops; 340 inode->i_fop = &fat_dir_operations; 341 342 MSDOS_I(inode)->i_start = le16_to_cpu(de->start); 343 if (sbi->fat_bits == 32) 344 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16); 345 346 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 347 error = fat_calc_dir_size(inode); 348 if (error < 0) 349 return error; 350 MSDOS_I(inode)->mmu_private = inode->i_size; 351 352 inode->i_nlink = fat_subdirs(inode); 353 } else { /* not a directory */ 354 inode->i_generation |= 1; 355 inode->i_mode = MSDOS_MKMODE(de->attr, 356 ((sbi->options.showexec && 357 !is_exec(de->ext)) 358 ? S_IRUGO|S_IWUGO : S_IRWXUGO) 359 & ~sbi->options.fs_fmask) | S_IFREG; 360 MSDOS_I(inode)->i_start = le16_to_cpu(de->start); 361 if (sbi->fat_bits == 32) 362 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16); 363 364 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 365 inode->i_size = le32_to_cpu(de->size); 366 inode->i_op = &fat_file_inode_operations; 367 inode->i_fop = &fat_file_operations; 368 inode->i_mapping->a_ops = &fat_aops; 369 MSDOS_I(inode)->mmu_private = inode->i_size; 370 } 371 if (de->attr & ATTR_SYS) { 372 if (sbi->options.sys_immutable) 373 inode->i_flags |= S_IMMUTABLE; 374 } 375 MSDOS_I(inode)->i_attrs = de->attr & ATTR_UNUSED; 376 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 377 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 378 inode->i_mtime.tv_sec = 379 date_dos2unix(le16_to_cpu(de->time), le16_to_cpu(de->date)); 380 inode->i_mtime.tv_nsec = 0; 381 if (sbi->options.isvfat) { 382 int secs = de->ctime_cs / 100; 383 int csecs = de->ctime_cs % 100; 384 inode->i_ctime.tv_sec = 385 date_dos2unix(le16_to_cpu(de->ctime), 386 le16_to_cpu(de->cdate)) + secs; 387 inode->i_ctime.tv_nsec = csecs * 10000000; 388 inode->i_atime.tv_sec = 389 date_dos2unix(0, le16_to_cpu(de->adate)); 390 inode->i_atime.tv_nsec = 0; 391 } else 392 inode->i_ctime = inode->i_atime = inode->i_mtime; 393 394 return 0; 395 } 396 397 struct inode *fat_build_inode(struct super_block *sb, 398 struct msdos_dir_entry *de, loff_t i_pos) 399 { 400 struct inode *inode; 401 int err; 402 403 inode = fat_iget(sb, i_pos); 404 if (inode) 405 goto out; 406 inode = new_inode(sb); 407 if (!inode) { 408 inode = ERR_PTR(-ENOMEM); 409 goto out; 410 } 411 inode->i_ino = iunique(sb, MSDOS_ROOT_INO); 412 inode->i_version = 1; 413 err = fat_fill_inode(inode, de); 414 if (err) { 415 iput(inode); 416 inode = ERR_PTR(err); 417 goto out; 418 } 419 fat_attach(inode, i_pos); 420 insert_inode_hash(inode); 421 out: 422 return inode; 423 } 424 425 EXPORT_SYMBOL_GPL(fat_build_inode); 426 427 static void fat_delete_inode(struct inode *inode) 428 { 429 truncate_inode_pages(&inode->i_data, 0); 430 431 if (!is_bad_inode(inode)) { 432 inode->i_size = 0; 433 fat_truncate(inode); 434 } 435 clear_inode(inode); 436 } 437 438 static void fat_clear_inode(struct inode *inode) 439 { 440 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 441 442 if (is_bad_inode(inode)) 443 return; 444 lock_kernel(); 445 spin_lock(&sbi->inode_hash_lock); 446 fat_cache_inval_inode(inode); 447 hlist_del_init(&MSDOS_I(inode)->i_fat_hash); 448 spin_unlock(&sbi->inode_hash_lock); 449 unlock_kernel(); 450 } 451 452 static void fat_write_super(struct super_block *sb) 453 { 454 sb->s_dirt = 0; 455 456 if (!(sb->s_flags & MS_RDONLY)) 457 fat_clusters_flush(sb); 458 } 459 460 static void fat_put_super(struct super_block *sb) 461 { 462 struct msdos_sb_info *sbi = MSDOS_SB(sb); 463 464 if (sbi->nls_disk) { 465 unload_nls(sbi->nls_disk); 466 sbi->nls_disk = NULL; 467 sbi->options.codepage = fat_default_codepage; 468 } 469 if (sbi->nls_io) { 470 unload_nls(sbi->nls_io); 471 sbi->nls_io = NULL; 472 } 473 if (sbi->options.iocharset != fat_default_iocharset) { 474 kfree(sbi->options.iocharset); 475 sbi->options.iocharset = fat_default_iocharset; 476 } 477 478 sb->s_fs_info = NULL; 479 kfree(sbi); 480 } 481 482 static struct kmem_cache *fat_inode_cachep; 483 484 static struct inode *fat_alloc_inode(struct super_block *sb) 485 { 486 struct msdos_inode_info *ei; 487 ei = kmem_cache_alloc(fat_inode_cachep, GFP_KERNEL); 488 if (!ei) 489 return NULL; 490 return &ei->vfs_inode; 491 } 492 493 static void fat_destroy_inode(struct inode *inode) 494 { 495 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode)); 496 } 497 498 static void init_once(void * foo, struct kmem_cache * cachep, unsigned long flags) 499 { 500 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo; 501 502 if (flags & SLAB_CTOR_CONSTRUCTOR) { 503 spin_lock_init(&ei->cache_lru_lock); 504 ei->nr_caches = 0; 505 ei->cache_valid_id = FAT_CACHE_VALID + 1; 506 INIT_LIST_HEAD(&ei->cache_lru); 507 INIT_HLIST_NODE(&ei->i_fat_hash); 508 inode_init_once(&ei->vfs_inode); 509 } 510 } 511 512 static int __init fat_init_inodecache(void) 513 { 514 fat_inode_cachep = kmem_cache_create("fat_inode_cache", 515 sizeof(struct msdos_inode_info), 516 0, (SLAB_RECLAIM_ACCOUNT| 517 SLAB_MEM_SPREAD), 518 init_once, NULL); 519 if (fat_inode_cachep == NULL) 520 return -ENOMEM; 521 return 0; 522 } 523 524 static void __exit fat_destroy_inodecache(void) 525 { 526 kmem_cache_destroy(fat_inode_cachep); 527 } 528 529 static int fat_remount(struct super_block *sb, int *flags, char *data) 530 { 531 struct msdos_sb_info *sbi = MSDOS_SB(sb); 532 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME); 533 return 0; 534 } 535 536 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf) 537 { 538 struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb); 539 540 /* If the count of free cluster is still unknown, counts it here. */ 541 if (sbi->free_clusters == -1) { 542 int err = fat_count_free_clusters(dentry->d_sb); 543 if (err) 544 return err; 545 } 546 547 buf->f_type = dentry->d_sb->s_magic; 548 buf->f_bsize = sbi->cluster_size; 549 buf->f_blocks = sbi->max_cluster - FAT_START_ENT; 550 buf->f_bfree = sbi->free_clusters; 551 buf->f_bavail = sbi->free_clusters; 552 buf->f_namelen = sbi->options.isvfat ? 260 : 12; 553 554 return 0; 555 } 556 557 static int fat_write_inode(struct inode *inode, int wait) 558 { 559 struct super_block *sb = inode->i_sb; 560 struct msdos_sb_info *sbi = MSDOS_SB(sb); 561 struct buffer_head *bh; 562 struct msdos_dir_entry *raw_entry; 563 loff_t i_pos; 564 int err = 0; 565 566 retry: 567 i_pos = MSDOS_I(inode)->i_pos; 568 if (inode->i_ino == MSDOS_ROOT_INO || !i_pos) 569 return 0; 570 571 lock_kernel(); 572 bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits); 573 if (!bh) { 574 printk(KERN_ERR "FAT: unable to read inode block " 575 "for updating (i_pos %lld)\n", i_pos); 576 err = -EIO; 577 goto out; 578 } 579 spin_lock(&sbi->inode_hash_lock); 580 if (i_pos != MSDOS_I(inode)->i_pos) { 581 spin_unlock(&sbi->inode_hash_lock); 582 brelse(bh); 583 unlock_kernel(); 584 goto retry; 585 } 586 587 raw_entry = &((struct msdos_dir_entry *) (bh->b_data)) 588 [i_pos & (sbi->dir_per_block - 1)]; 589 if (S_ISDIR(inode->i_mode)) 590 raw_entry->size = 0; 591 else 592 raw_entry->size = cpu_to_le32(inode->i_size); 593 raw_entry->attr = fat_attr(inode); 594 raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart); 595 raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16); 596 fat_date_unix2dos(inode->i_mtime.tv_sec, &raw_entry->time, &raw_entry->date); 597 if (sbi->options.isvfat) { 598 __le16 atime; 599 fat_date_unix2dos(inode->i_ctime.tv_sec,&raw_entry->ctime,&raw_entry->cdate); 600 fat_date_unix2dos(inode->i_atime.tv_sec,&atime,&raw_entry->adate); 601 raw_entry->ctime_cs = (inode->i_ctime.tv_sec & 1) * 100 + 602 inode->i_ctime.tv_nsec / 10000000; 603 } 604 spin_unlock(&sbi->inode_hash_lock); 605 mark_buffer_dirty(bh); 606 if (wait) 607 err = sync_dirty_buffer(bh); 608 brelse(bh); 609 out: 610 unlock_kernel(); 611 return err; 612 } 613 614 int fat_sync_inode(struct inode *inode) 615 { 616 return fat_write_inode(inode, 1); 617 } 618 619 EXPORT_SYMBOL_GPL(fat_sync_inode); 620 621 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt); 622 static const struct super_operations fat_sops = { 623 .alloc_inode = fat_alloc_inode, 624 .destroy_inode = fat_destroy_inode, 625 .write_inode = fat_write_inode, 626 .delete_inode = fat_delete_inode, 627 .put_super = fat_put_super, 628 .write_super = fat_write_super, 629 .statfs = fat_statfs, 630 .clear_inode = fat_clear_inode, 631 .remount_fs = fat_remount, 632 633 .read_inode = make_bad_inode, 634 635 .show_options = fat_show_options, 636 }; 637 638 /* 639 * a FAT file handle with fhtype 3 is 640 * 0/ i_ino - for fast, reliable lookup if still in the cache 641 * 1/ i_generation - to see if i_ino is still valid 642 * bit 0 == 0 iff directory 643 * 2/ i_pos(8-39) - if ino has changed, but still in cache 644 * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos 645 * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc 646 * 647 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum 648 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits 649 * of i_logstart is used to store the directory entry offset. 650 */ 651 652 static struct dentry * 653 fat_decode_fh(struct super_block *sb, __u32 *fh, int len, int fhtype, 654 int (*acceptable)(void *context, struct dentry *de), 655 void *context) 656 { 657 if (fhtype != 3) 658 return ERR_PTR(-ESTALE); 659 if (len < 5) 660 return ERR_PTR(-ESTALE); 661 662 return sb->s_export_op->find_exported_dentry(sb, fh, NULL, acceptable, context); 663 } 664 665 static struct dentry *fat_get_dentry(struct super_block *sb, void *inump) 666 { 667 struct inode *inode = NULL; 668 struct dentry *result; 669 __u32 *fh = inump; 670 671 inode = iget(sb, fh[0]); 672 if (!inode || is_bad_inode(inode) || inode->i_generation != fh[1]) { 673 if (inode) 674 iput(inode); 675 inode = NULL; 676 } 677 if (!inode) { 678 loff_t i_pos; 679 int i_logstart = fh[3] & 0x0fffffff; 680 681 i_pos = (loff_t)fh[2] << 8; 682 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28); 683 684 /* try 2 - see if i_pos is in F-d-c 685 * require i_logstart to be the same 686 * Will fail if you truncate and then re-write 687 */ 688 689 inode = fat_iget(sb, i_pos); 690 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) { 691 iput(inode); 692 inode = NULL; 693 } 694 } 695 if (!inode) { 696 /* For now, do nothing 697 * What we could do is: 698 * follow the file starting at fh[4], and record 699 * the ".." entry, and the name of the fh[2] entry. 700 * The follow the ".." file finding the next step up. 701 * This way we build a path to the root of 702 * the tree. If this works, we lookup the path and so 703 * get this inode into the cache. 704 * Finally try the fat_iget lookup again 705 * If that fails, then weare totally out of luck 706 * But all that is for another day 707 */ 708 } 709 if (!inode) 710 return ERR_PTR(-ESTALE); 711 712 713 /* now to find a dentry. 714 * If possible, get a well-connected one 715 */ 716 result = d_alloc_anon(inode); 717 if (result == NULL) { 718 iput(inode); 719 return ERR_PTR(-ENOMEM); 720 } 721 result->d_op = sb->s_root->d_op; 722 return result; 723 } 724 725 static int 726 fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable) 727 { 728 int len = *lenp; 729 struct inode *inode = de->d_inode; 730 u32 ipos_h, ipos_m, ipos_l; 731 732 if (len < 5) 733 return 255; /* no room */ 734 735 ipos_h = MSDOS_I(inode)->i_pos >> 8; 736 ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24; 737 ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28; 738 *lenp = 5; 739 fh[0] = inode->i_ino; 740 fh[1] = inode->i_generation; 741 fh[2] = ipos_h; 742 fh[3] = ipos_m | MSDOS_I(inode)->i_logstart; 743 spin_lock(&de->d_lock); 744 fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart; 745 spin_unlock(&de->d_lock); 746 return 3; 747 } 748 749 static struct dentry *fat_get_parent(struct dentry *child) 750 { 751 struct buffer_head *bh; 752 struct msdos_dir_entry *de; 753 loff_t i_pos; 754 struct dentry *parent; 755 struct inode *inode; 756 int err; 757 758 lock_kernel(); 759 760 err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos); 761 if (err) { 762 parent = ERR_PTR(err); 763 goto out; 764 } 765 inode = fat_build_inode(child->d_sb, de, i_pos); 766 brelse(bh); 767 if (IS_ERR(inode)) { 768 parent = ERR_PTR(PTR_ERR(inode)); 769 goto out; 770 } 771 parent = d_alloc_anon(inode); 772 if (!parent) { 773 iput(inode); 774 parent = ERR_PTR(-ENOMEM); 775 } 776 out: 777 unlock_kernel(); 778 779 return parent; 780 } 781 782 static struct export_operations fat_export_ops = { 783 .decode_fh = fat_decode_fh, 784 .encode_fh = fat_encode_fh, 785 .get_dentry = fat_get_dentry, 786 .get_parent = fat_get_parent, 787 }; 788 789 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt) 790 { 791 struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb); 792 struct fat_mount_options *opts = &sbi->options; 793 int isvfat = opts->isvfat; 794 795 if (opts->fs_uid != 0) 796 seq_printf(m, ",uid=%u", opts->fs_uid); 797 if (opts->fs_gid != 0) 798 seq_printf(m, ",gid=%u", opts->fs_gid); 799 seq_printf(m, ",fmask=%04o", opts->fs_fmask); 800 seq_printf(m, ",dmask=%04o", opts->fs_dmask); 801 if (sbi->nls_disk) 802 seq_printf(m, ",codepage=%s", sbi->nls_disk->charset); 803 if (isvfat) { 804 if (sbi->nls_io) 805 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset); 806 807 switch (opts->shortname) { 808 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95: 809 seq_puts(m, ",shortname=win95"); 810 break; 811 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT: 812 seq_puts(m, ",shortname=winnt"); 813 break; 814 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95: 815 seq_puts(m, ",shortname=mixed"); 816 break; 817 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95: 818 /* seq_puts(m, ",shortname=lower"); */ 819 break; 820 default: 821 seq_puts(m, ",shortname=unknown"); 822 break; 823 } 824 } 825 if (opts->name_check != 'n') 826 seq_printf(m, ",check=%c", opts->name_check); 827 if (opts->quiet) 828 seq_puts(m, ",quiet"); 829 if (opts->showexec) 830 seq_puts(m, ",showexec"); 831 if (opts->sys_immutable) 832 seq_puts(m, ",sys_immutable"); 833 if (!isvfat) { 834 if (opts->dotsOK) 835 seq_puts(m, ",dotsOK=yes"); 836 if (opts->nocase) 837 seq_puts(m, ",nocase"); 838 } else { 839 if (opts->utf8) 840 seq_puts(m, ",utf8"); 841 if (opts->unicode_xlate) 842 seq_puts(m, ",uni_xlate"); 843 if (!opts->numtail) 844 seq_puts(m, ",nonumtail"); 845 } 846 847 return 0; 848 } 849 850 enum { 851 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid, 852 Opt_umask, Opt_dmask, Opt_fmask, Opt_codepage, Opt_nocase, 853 Opt_quiet, Opt_showexec, Opt_debug, Opt_immutable, 854 Opt_dots, Opt_nodots, 855 Opt_charset, Opt_shortname_lower, Opt_shortname_win95, 856 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes, 857 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes, 858 Opt_obsolate, Opt_flush, Opt_err, 859 }; 860 861 static match_table_t fat_tokens = { 862 {Opt_check_r, "check=relaxed"}, 863 {Opt_check_s, "check=strict"}, 864 {Opt_check_n, "check=normal"}, 865 {Opt_check_r, "check=r"}, 866 {Opt_check_s, "check=s"}, 867 {Opt_check_n, "check=n"}, 868 {Opt_uid, "uid=%u"}, 869 {Opt_gid, "gid=%u"}, 870 {Opt_umask, "umask=%o"}, 871 {Opt_dmask, "dmask=%o"}, 872 {Opt_fmask, "fmask=%o"}, 873 {Opt_codepage, "codepage=%u"}, 874 {Opt_nocase, "nocase"}, 875 {Opt_quiet, "quiet"}, 876 {Opt_showexec, "showexec"}, 877 {Opt_debug, "debug"}, 878 {Opt_immutable, "sys_immutable"}, 879 {Opt_obsolate, "conv=binary"}, 880 {Opt_obsolate, "conv=text"}, 881 {Opt_obsolate, "conv=auto"}, 882 {Opt_obsolate, "conv=b"}, 883 {Opt_obsolate, "conv=t"}, 884 {Opt_obsolate, "conv=a"}, 885 {Opt_obsolate, "fat=%u"}, 886 {Opt_obsolate, "blocksize=%u"}, 887 {Opt_obsolate, "cvf_format=%20s"}, 888 {Opt_obsolate, "cvf_options=%100s"}, 889 {Opt_obsolate, "posix"}, 890 {Opt_flush, "flush"}, 891 {Opt_err, NULL}, 892 }; 893 static match_table_t msdos_tokens = { 894 {Opt_nodots, "nodots"}, 895 {Opt_nodots, "dotsOK=no"}, 896 {Opt_dots, "dots"}, 897 {Opt_dots, "dotsOK=yes"}, 898 {Opt_err, NULL} 899 }; 900 static match_table_t vfat_tokens = { 901 {Opt_charset, "iocharset=%s"}, 902 {Opt_shortname_lower, "shortname=lower"}, 903 {Opt_shortname_win95, "shortname=win95"}, 904 {Opt_shortname_winnt, "shortname=winnt"}, 905 {Opt_shortname_mixed, "shortname=mixed"}, 906 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */ 907 {Opt_utf8_no, "utf8=no"}, 908 {Opt_utf8_no, "utf8=false"}, 909 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */ 910 {Opt_utf8_yes, "utf8=yes"}, 911 {Opt_utf8_yes, "utf8=true"}, 912 {Opt_utf8_yes, "utf8"}, 913 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */ 914 {Opt_uni_xl_no, "uni_xlate=no"}, 915 {Opt_uni_xl_no, "uni_xlate=false"}, 916 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */ 917 {Opt_uni_xl_yes, "uni_xlate=yes"}, 918 {Opt_uni_xl_yes, "uni_xlate=true"}, 919 {Opt_uni_xl_yes, "uni_xlate"}, 920 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */ 921 {Opt_nonumtail_no, "nonumtail=no"}, 922 {Opt_nonumtail_no, "nonumtail=false"}, 923 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */ 924 {Opt_nonumtail_yes, "nonumtail=yes"}, 925 {Opt_nonumtail_yes, "nonumtail=true"}, 926 {Opt_nonumtail_yes, "nonumtail"}, 927 {Opt_err, NULL} 928 }; 929 930 static int parse_options(char *options, int is_vfat, int silent, int *debug, 931 struct fat_mount_options *opts) 932 { 933 char *p; 934 substring_t args[MAX_OPT_ARGS]; 935 int option; 936 char *iocharset; 937 938 opts->isvfat = is_vfat; 939 940 opts->fs_uid = current->uid; 941 opts->fs_gid = current->gid; 942 opts->fs_fmask = opts->fs_dmask = current->fs->umask; 943 opts->codepage = fat_default_codepage; 944 opts->iocharset = fat_default_iocharset; 945 if (is_vfat) 946 opts->shortname = VFAT_SFN_DISPLAY_LOWER|VFAT_SFN_CREATE_WIN95; 947 else 948 opts->shortname = 0; 949 opts->name_check = 'n'; 950 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0; 951 opts->utf8 = opts->unicode_xlate = 0; 952 opts->numtail = 1; 953 opts->nocase = 0; 954 *debug = 0; 955 956 if (!options) 957 return 0; 958 959 while ((p = strsep(&options, ",")) != NULL) { 960 int token; 961 if (!*p) 962 continue; 963 964 token = match_token(p, fat_tokens, args); 965 if (token == Opt_err) { 966 if (is_vfat) 967 token = match_token(p, vfat_tokens, args); 968 else 969 token = match_token(p, msdos_tokens, args); 970 } 971 switch (token) { 972 case Opt_check_s: 973 opts->name_check = 's'; 974 break; 975 case Opt_check_r: 976 opts->name_check = 'r'; 977 break; 978 case Opt_check_n: 979 opts->name_check = 'n'; 980 break; 981 case Opt_nocase: 982 if (!is_vfat) 983 opts->nocase = 1; 984 else { 985 /* for backward compatibility */ 986 opts->shortname = VFAT_SFN_DISPLAY_WIN95 987 | VFAT_SFN_CREATE_WIN95; 988 } 989 break; 990 case Opt_quiet: 991 opts->quiet = 1; 992 break; 993 case Opt_showexec: 994 opts->showexec = 1; 995 break; 996 case Opt_debug: 997 *debug = 1; 998 break; 999 case Opt_immutable: 1000 opts->sys_immutable = 1; 1001 break; 1002 case Opt_uid: 1003 if (match_int(&args[0], &option)) 1004 return 0; 1005 opts->fs_uid = option; 1006 break; 1007 case Opt_gid: 1008 if (match_int(&args[0], &option)) 1009 return 0; 1010 opts->fs_gid = option; 1011 break; 1012 case Opt_umask: 1013 if (match_octal(&args[0], &option)) 1014 return 0; 1015 opts->fs_fmask = opts->fs_dmask = option; 1016 break; 1017 case Opt_dmask: 1018 if (match_octal(&args[0], &option)) 1019 return 0; 1020 opts->fs_dmask = option; 1021 break; 1022 case Opt_fmask: 1023 if (match_octal(&args[0], &option)) 1024 return 0; 1025 opts->fs_fmask = option; 1026 break; 1027 case Opt_codepage: 1028 if (match_int(&args[0], &option)) 1029 return 0; 1030 opts->codepage = option; 1031 break; 1032 case Opt_flush: 1033 opts->flush = 1; 1034 break; 1035 1036 /* msdos specific */ 1037 case Opt_dots: 1038 opts->dotsOK = 1; 1039 break; 1040 case Opt_nodots: 1041 opts->dotsOK = 0; 1042 break; 1043 1044 /* vfat specific */ 1045 case Opt_charset: 1046 if (opts->iocharset != fat_default_iocharset) 1047 kfree(opts->iocharset); 1048 iocharset = match_strdup(&args[0]); 1049 if (!iocharset) 1050 return -ENOMEM; 1051 opts->iocharset = iocharset; 1052 break; 1053 case Opt_shortname_lower: 1054 opts->shortname = VFAT_SFN_DISPLAY_LOWER 1055 | VFAT_SFN_CREATE_WIN95; 1056 break; 1057 case Opt_shortname_win95: 1058 opts->shortname = VFAT_SFN_DISPLAY_WIN95 1059 | VFAT_SFN_CREATE_WIN95; 1060 break; 1061 case Opt_shortname_winnt: 1062 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1063 | VFAT_SFN_CREATE_WINNT; 1064 break; 1065 case Opt_shortname_mixed: 1066 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1067 | VFAT_SFN_CREATE_WIN95; 1068 break; 1069 case Opt_utf8_no: /* 0 or no or false */ 1070 opts->utf8 = 0; 1071 break; 1072 case Opt_utf8_yes: /* empty or 1 or yes or true */ 1073 opts->utf8 = 1; 1074 break; 1075 case Opt_uni_xl_no: /* 0 or no or false */ 1076 opts->unicode_xlate = 0; 1077 break; 1078 case Opt_uni_xl_yes: /* empty or 1 or yes or true */ 1079 opts->unicode_xlate = 1; 1080 break; 1081 case Opt_nonumtail_no: /* 0 or no or false */ 1082 opts->numtail = 1; /* negated option */ 1083 break; 1084 case Opt_nonumtail_yes: /* empty or 1 or yes or true */ 1085 opts->numtail = 0; /* negated option */ 1086 break; 1087 1088 /* obsolete mount options */ 1089 case Opt_obsolate: 1090 printk(KERN_INFO "FAT: \"%s\" option is obsolete, " 1091 "not supported now\n", p); 1092 break; 1093 /* unknown option */ 1094 default: 1095 if (!silent) { 1096 printk(KERN_ERR 1097 "FAT: Unrecognized mount option \"%s\" " 1098 "or missing value\n", p); 1099 } 1100 return -EINVAL; 1101 } 1102 } 1103 /* UTF-8 doesn't provide FAT semantics */ 1104 if (!strcmp(opts->iocharset, "utf8")) { 1105 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset" 1106 " for FAT filesystems, filesystem will be case sensitive!\n"); 1107 } 1108 1109 if (opts->unicode_xlate) 1110 opts->utf8 = 0; 1111 1112 return 0; 1113 } 1114 1115 static int fat_read_root(struct inode *inode) 1116 { 1117 struct super_block *sb = inode->i_sb; 1118 struct msdos_sb_info *sbi = MSDOS_SB(sb); 1119 int error; 1120 1121 MSDOS_I(inode)->i_pos = 0; 1122 inode->i_uid = sbi->options.fs_uid; 1123 inode->i_gid = sbi->options.fs_gid; 1124 inode->i_version++; 1125 inode->i_generation = 0; 1126 inode->i_mode = (S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR; 1127 inode->i_op = sbi->dir_ops; 1128 inode->i_fop = &fat_dir_operations; 1129 if (sbi->fat_bits == 32) { 1130 MSDOS_I(inode)->i_start = sbi->root_cluster; 1131 error = fat_calc_dir_size(inode); 1132 if (error < 0) 1133 return error; 1134 } else { 1135 MSDOS_I(inode)->i_start = 0; 1136 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry); 1137 } 1138 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 1139 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 1140 MSDOS_I(inode)->i_logstart = 0; 1141 MSDOS_I(inode)->mmu_private = inode->i_size; 1142 1143 MSDOS_I(inode)->i_attrs = ATTR_NONE; 1144 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0; 1145 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0; 1146 inode->i_nlink = fat_subdirs(inode)+2; 1147 1148 return 0; 1149 } 1150 1151 /* 1152 * Read the super block of an MS-DOS FS. 1153 */ 1154 int fat_fill_super(struct super_block *sb, void *data, int silent, 1155 const struct inode_operations *fs_dir_inode_ops, int isvfat) 1156 { 1157 struct inode *root_inode = NULL; 1158 struct buffer_head *bh; 1159 struct fat_boot_sector *b; 1160 struct msdos_sb_info *sbi; 1161 u16 logical_sector_size; 1162 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors; 1163 int debug; 1164 unsigned int media; 1165 long error; 1166 char buf[50]; 1167 1168 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL); 1169 if (!sbi) 1170 return -ENOMEM; 1171 sb->s_fs_info = sbi; 1172 1173 sb->s_flags |= MS_NODIRATIME; 1174 sb->s_magic = MSDOS_SUPER_MAGIC; 1175 sb->s_op = &fat_sops; 1176 sb->s_export_op = &fat_export_ops; 1177 sbi->dir_ops = fs_dir_inode_ops; 1178 1179 error = parse_options(data, isvfat, silent, &debug, &sbi->options); 1180 if (error) 1181 goto out_fail; 1182 1183 error = -EIO; 1184 sb_min_blocksize(sb, 512); 1185 bh = sb_bread(sb, 0); 1186 if (bh == NULL) { 1187 printk(KERN_ERR "FAT: unable to read boot sector\n"); 1188 goto out_fail; 1189 } 1190 1191 b = (struct fat_boot_sector *) bh->b_data; 1192 if (!b->reserved) { 1193 if (!silent) 1194 printk(KERN_ERR "FAT: bogus number of reserved sectors\n"); 1195 brelse(bh); 1196 goto out_invalid; 1197 } 1198 if (!b->fats) { 1199 if (!silent) 1200 printk(KERN_ERR "FAT: bogus number of FAT structure\n"); 1201 brelse(bh); 1202 goto out_invalid; 1203 } 1204 1205 /* 1206 * Earlier we checked here that b->secs_track and b->head are nonzero, 1207 * but it turns out valid FAT filesystems can have zero there. 1208 */ 1209 1210 media = b->media; 1211 if (!FAT_VALID_MEDIA(media)) { 1212 if (!silent) 1213 printk(KERN_ERR "FAT: invalid media value (0x%02x)\n", 1214 media); 1215 brelse(bh); 1216 goto out_invalid; 1217 } 1218 logical_sector_size = 1219 le16_to_cpu(get_unaligned((__le16 *)&b->sector_size)); 1220 if (!logical_sector_size 1221 || (logical_sector_size & (logical_sector_size - 1)) 1222 || (logical_sector_size < 512) 1223 || (PAGE_CACHE_SIZE < logical_sector_size)) { 1224 if (!silent) 1225 printk(KERN_ERR "FAT: bogus logical sector size %u\n", 1226 logical_sector_size); 1227 brelse(bh); 1228 goto out_invalid; 1229 } 1230 sbi->sec_per_clus = b->sec_per_clus; 1231 if (!sbi->sec_per_clus 1232 || (sbi->sec_per_clus & (sbi->sec_per_clus - 1))) { 1233 if (!silent) 1234 printk(KERN_ERR "FAT: bogus sectors per cluster %u\n", 1235 sbi->sec_per_clus); 1236 brelse(bh); 1237 goto out_invalid; 1238 } 1239 1240 if (logical_sector_size < sb->s_blocksize) { 1241 printk(KERN_ERR "FAT: logical sector size too small for device" 1242 " (logical sector size = %u)\n", logical_sector_size); 1243 brelse(bh); 1244 goto out_fail; 1245 } 1246 if (logical_sector_size > sb->s_blocksize) { 1247 brelse(bh); 1248 1249 if (!sb_set_blocksize(sb, logical_sector_size)) { 1250 printk(KERN_ERR "FAT: unable to set blocksize %u\n", 1251 logical_sector_size); 1252 goto out_fail; 1253 } 1254 bh = sb_bread(sb, 0); 1255 if (bh == NULL) { 1256 printk(KERN_ERR "FAT: unable to read boot sector" 1257 " (logical sector size = %lu)\n", 1258 sb->s_blocksize); 1259 goto out_fail; 1260 } 1261 b = (struct fat_boot_sector *) bh->b_data; 1262 } 1263 1264 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus; 1265 sbi->cluster_bits = ffs(sbi->cluster_size) - 1; 1266 sbi->fats = b->fats; 1267 sbi->fat_bits = 0; /* Don't know yet */ 1268 sbi->fat_start = le16_to_cpu(b->reserved); 1269 sbi->fat_length = le16_to_cpu(b->fat_length); 1270 sbi->root_cluster = 0; 1271 sbi->free_clusters = -1; /* Don't know yet */ 1272 sbi->prev_free = FAT_START_ENT; 1273 1274 if (!sbi->fat_length && b->fat32_length) { 1275 struct fat_boot_fsinfo *fsinfo; 1276 struct buffer_head *fsinfo_bh; 1277 1278 /* Must be FAT32 */ 1279 sbi->fat_bits = 32; 1280 sbi->fat_length = le32_to_cpu(b->fat32_length); 1281 sbi->root_cluster = le32_to_cpu(b->root_cluster); 1282 1283 sb->s_maxbytes = 0xffffffff; 1284 1285 /* MC - if info_sector is 0, don't multiply by 0 */ 1286 sbi->fsinfo_sector = le16_to_cpu(b->info_sector); 1287 if (sbi->fsinfo_sector == 0) 1288 sbi->fsinfo_sector = 1; 1289 1290 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector); 1291 if (fsinfo_bh == NULL) { 1292 printk(KERN_ERR "FAT: bread failed, FSINFO block" 1293 " (sector = %lu)\n", sbi->fsinfo_sector); 1294 brelse(bh); 1295 goto out_fail; 1296 } 1297 1298 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data; 1299 if (!IS_FSINFO(fsinfo)) { 1300 printk(KERN_WARNING 1301 "FAT: Did not find valid FSINFO signature.\n" 1302 " Found signature1 0x%08x signature2 0x%08x" 1303 " (sector = %lu)\n", 1304 le32_to_cpu(fsinfo->signature1), 1305 le32_to_cpu(fsinfo->signature2), 1306 sbi->fsinfo_sector); 1307 } else { 1308 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters); 1309 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster); 1310 } 1311 1312 brelse(fsinfo_bh); 1313 } 1314 1315 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry); 1316 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1; 1317 1318 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length; 1319 sbi->dir_entries = 1320 le16_to_cpu(get_unaligned((__le16 *)&b->dir_entries)); 1321 if (sbi->dir_entries & (sbi->dir_per_block - 1)) { 1322 if (!silent) 1323 printk(KERN_ERR "FAT: bogus directroy-entries per block" 1324 " (%u)\n", sbi->dir_entries); 1325 brelse(bh); 1326 goto out_invalid; 1327 } 1328 1329 rootdir_sectors = sbi->dir_entries 1330 * sizeof(struct msdos_dir_entry) / sb->s_blocksize; 1331 sbi->data_start = sbi->dir_start + rootdir_sectors; 1332 total_sectors = le16_to_cpu(get_unaligned((__le16 *)&b->sectors)); 1333 if (total_sectors == 0) 1334 total_sectors = le32_to_cpu(b->total_sect); 1335 1336 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus; 1337 1338 if (sbi->fat_bits != 32) 1339 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12; 1340 1341 /* check that FAT table does not overflow */ 1342 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits; 1343 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT); 1344 if (total_clusters > MAX_FAT(sb)) { 1345 if (!silent) 1346 printk(KERN_ERR "FAT: count of clusters too big (%u)\n", 1347 total_clusters); 1348 brelse(bh); 1349 goto out_invalid; 1350 } 1351 1352 sbi->max_cluster = total_clusters + FAT_START_ENT; 1353 /* check the free_clusters, it's not necessarily correct */ 1354 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters) 1355 sbi->free_clusters = -1; 1356 /* check the prev_free, it's not necessarily correct */ 1357 sbi->prev_free %= sbi->max_cluster; 1358 if (sbi->prev_free < FAT_START_ENT) 1359 sbi->prev_free = FAT_START_ENT; 1360 1361 brelse(bh); 1362 1363 /* set up enough so that it can read an inode */ 1364 fat_hash_init(sb); 1365 fat_ent_access_init(sb); 1366 1367 /* 1368 * The low byte of FAT's first entry must have same value with 1369 * media-field. But in real world, too many devices is 1370 * writing wrong value. So, removed that validity check. 1371 * 1372 * if (FAT_FIRST_ENT(sb, media) != first) 1373 */ 1374 1375 error = -EINVAL; 1376 sprintf(buf, "cp%d", sbi->options.codepage); 1377 sbi->nls_disk = load_nls(buf); 1378 if (!sbi->nls_disk) { 1379 printk(KERN_ERR "FAT: codepage %s not found\n", buf); 1380 goto out_fail; 1381 } 1382 1383 /* FIXME: utf8 is using iocharset for upper/lower conversion */ 1384 if (sbi->options.isvfat) { 1385 sbi->nls_io = load_nls(sbi->options.iocharset); 1386 if (!sbi->nls_io) { 1387 printk(KERN_ERR "FAT: IO charset %s not found\n", 1388 sbi->options.iocharset); 1389 goto out_fail; 1390 } 1391 } 1392 1393 error = -ENOMEM; 1394 root_inode = new_inode(sb); 1395 if (!root_inode) 1396 goto out_fail; 1397 root_inode->i_ino = MSDOS_ROOT_INO; 1398 root_inode->i_version = 1; 1399 error = fat_read_root(root_inode); 1400 if (error < 0) 1401 goto out_fail; 1402 error = -ENOMEM; 1403 insert_inode_hash(root_inode); 1404 sb->s_root = d_alloc_root(root_inode); 1405 if (!sb->s_root) { 1406 printk(KERN_ERR "FAT: get root inode failed\n"); 1407 goto out_fail; 1408 } 1409 1410 return 0; 1411 1412 out_invalid: 1413 error = -EINVAL; 1414 if (!silent) 1415 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem" 1416 " on dev %s.\n", sb->s_id); 1417 1418 out_fail: 1419 if (root_inode) 1420 iput(root_inode); 1421 if (sbi->nls_io) 1422 unload_nls(sbi->nls_io); 1423 if (sbi->nls_disk) 1424 unload_nls(sbi->nls_disk); 1425 if (sbi->options.iocharset != fat_default_iocharset) 1426 kfree(sbi->options.iocharset); 1427 sb->s_fs_info = NULL; 1428 kfree(sbi); 1429 return error; 1430 } 1431 1432 EXPORT_SYMBOL_GPL(fat_fill_super); 1433 1434 /* 1435 * helper function for fat_flush_inodes. This writes both the inode 1436 * and the file data blocks, waiting for in flight data blocks before 1437 * the start of the call. It does not wait for any io started 1438 * during the call 1439 */ 1440 static int writeback_inode(struct inode *inode) 1441 { 1442 1443 int ret; 1444 struct address_space *mapping = inode->i_mapping; 1445 struct writeback_control wbc = { 1446 .sync_mode = WB_SYNC_NONE, 1447 .nr_to_write = 0, 1448 }; 1449 /* if we used WB_SYNC_ALL, sync_inode waits for the io for the 1450 * inode to finish. So WB_SYNC_NONE is sent down to sync_inode 1451 * and filemap_fdatawrite is used for the data blocks 1452 */ 1453 ret = sync_inode(inode, &wbc); 1454 if (!ret) 1455 ret = filemap_fdatawrite(mapping); 1456 return ret; 1457 } 1458 1459 /* 1460 * write data and metadata corresponding to i1 and i2. The io is 1461 * started but we do not wait for any of it to finish. 1462 * 1463 * filemap_flush is used for the block device, so if there is a dirty 1464 * page for a block already in flight, we will not wait and start the 1465 * io over again 1466 */ 1467 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2) 1468 { 1469 int ret = 0; 1470 if (!MSDOS_SB(sb)->options.flush) 1471 return 0; 1472 if (i1) 1473 ret = writeback_inode(i1); 1474 if (!ret && i2) 1475 ret = writeback_inode(i2); 1476 if (!ret) { 1477 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping; 1478 ret = filemap_flush(mapping); 1479 } 1480 return ret; 1481 } 1482 EXPORT_SYMBOL_GPL(fat_flush_inodes); 1483 1484 static int __init init_fat_fs(void) 1485 { 1486 int err; 1487 1488 err = fat_cache_init(); 1489 if (err) 1490 return err; 1491 1492 err = fat_init_inodecache(); 1493 if (err) 1494 goto failed; 1495 1496 return 0; 1497 1498 failed: 1499 fat_cache_destroy(); 1500 return err; 1501 } 1502 1503 static void __exit exit_fat_fs(void) 1504 { 1505 fat_cache_destroy(); 1506 fat_destroy_inodecache(); 1507 } 1508 1509 module_init(init_fat_fs) 1510 module_exit(exit_fat_fs) 1511 1512 MODULE_LICENSE("GPL"); 1513