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