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_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == 503 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->quiet) 829 seq_puts(m, ",quiet"); 830 if (opts->showexec) 831 seq_puts(m, ",showexec"); 832 if (opts->sys_immutable) 833 seq_puts(m, ",sys_immutable"); 834 if (!isvfat) { 835 if (opts->dotsOK) 836 seq_puts(m, ",dotsOK=yes"); 837 if (opts->nocase) 838 seq_puts(m, ",nocase"); 839 } else { 840 if (opts->utf8) 841 seq_puts(m, ",utf8"); 842 if (opts->unicode_xlate) 843 seq_puts(m, ",uni_xlate"); 844 if (!opts->numtail) 845 seq_puts(m, ",nonumtail"); 846 } 847 848 return 0; 849 } 850 851 enum { 852 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid, 853 Opt_umask, Opt_dmask, Opt_fmask, Opt_codepage, Opt_nocase, 854 Opt_quiet, Opt_showexec, Opt_debug, Opt_immutable, 855 Opt_dots, Opt_nodots, 856 Opt_charset, Opt_shortname_lower, Opt_shortname_win95, 857 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes, 858 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes, 859 Opt_obsolate, Opt_flush, Opt_err, 860 }; 861 862 static match_table_t fat_tokens = { 863 {Opt_check_r, "check=relaxed"}, 864 {Opt_check_s, "check=strict"}, 865 {Opt_check_n, "check=normal"}, 866 {Opt_check_r, "check=r"}, 867 {Opt_check_s, "check=s"}, 868 {Opt_check_n, "check=n"}, 869 {Opt_uid, "uid=%u"}, 870 {Opt_gid, "gid=%u"}, 871 {Opt_umask, "umask=%o"}, 872 {Opt_dmask, "dmask=%o"}, 873 {Opt_fmask, "fmask=%o"}, 874 {Opt_codepage, "codepage=%u"}, 875 {Opt_nocase, "nocase"}, 876 {Opt_quiet, "quiet"}, 877 {Opt_showexec, "showexec"}, 878 {Opt_debug, "debug"}, 879 {Opt_immutable, "sys_immutable"}, 880 {Opt_obsolate, "conv=binary"}, 881 {Opt_obsolate, "conv=text"}, 882 {Opt_obsolate, "conv=auto"}, 883 {Opt_obsolate, "conv=b"}, 884 {Opt_obsolate, "conv=t"}, 885 {Opt_obsolate, "conv=a"}, 886 {Opt_obsolate, "fat=%u"}, 887 {Opt_obsolate, "blocksize=%u"}, 888 {Opt_obsolate, "cvf_format=%20s"}, 889 {Opt_obsolate, "cvf_options=%100s"}, 890 {Opt_obsolate, "posix"}, 891 {Opt_flush, "flush"}, 892 {Opt_err, NULL}, 893 }; 894 static match_table_t msdos_tokens = { 895 {Opt_nodots, "nodots"}, 896 {Opt_nodots, "dotsOK=no"}, 897 {Opt_dots, "dots"}, 898 {Opt_dots, "dotsOK=yes"}, 899 {Opt_err, NULL} 900 }; 901 static match_table_t vfat_tokens = { 902 {Opt_charset, "iocharset=%s"}, 903 {Opt_shortname_lower, "shortname=lower"}, 904 {Opt_shortname_win95, "shortname=win95"}, 905 {Opt_shortname_winnt, "shortname=winnt"}, 906 {Opt_shortname_mixed, "shortname=mixed"}, 907 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */ 908 {Opt_utf8_no, "utf8=no"}, 909 {Opt_utf8_no, "utf8=false"}, 910 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */ 911 {Opt_utf8_yes, "utf8=yes"}, 912 {Opt_utf8_yes, "utf8=true"}, 913 {Opt_utf8_yes, "utf8"}, 914 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */ 915 {Opt_uni_xl_no, "uni_xlate=no"}, 916 {Opt_uni_xl_no, "uni_xlate=false"}, 917 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */ 918 {Opt_uni_xl_yes, "uni_xlate=yes"}, 919 {Opt_uni_xl_yes, "uni_xlate=true"}, 920 {Opt_uni_xl_yes, "uni_xlate"}, 921 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */ 922 {Opt_nonumtail_no, "nonumtail=no"}, 923 {Opt_nonumtail_no, "nonumtail=false"}, 924 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */ 925 {Opt_nonumtail_yes, "nonumtail=yes"}, 926 {Opt_nonumtail_yes, "nonumtail=true"}, 927 {Opt_nonumtail_yes, "nonumtail"}, 928 {Opt_err, NULL} 929 }; 930 931 static int parse_options(char *options, int is_vfat, int silent, int *debug, 932 struct fat_mount_options *opts) 933 { 934 char *p; 935 substring_t args[MAX_OPT_ARGS]; 936 int option; 937 char *iocharset; 938 939 opts->isvfat = is_vfat; 940 941 opts->fs_uid = current->uid; 942 opts->fs_gid = current->gid; 943 opts->fs_fmask = opts->fs_dmask = current->fs->umask; 944 opts->codepage = fat_default_codepage; 945 opts->iocharset = fat_default_iocharset; 946 if (is_vfat) 947 opts->shortname = VFAT_SFN_DISPLAY_LOWER|VFAT_SFN_CREATE_WIN95; 948 else 949 opts->shortname = 0; 950 opts->name_check = 'n'; 951 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0; 952 opts->utf8 = opts->unicode_xlate = 0; 953 opts->numtail = 1; 954 opts->nocase = 0; 955 *debug = 0; 956 957 if (!options) 958 return 0; 959 960 while ((p = strsep(&options, ",")) != NULL) { 961 int token; 962 if (!*p) 963 continue; 964 965 token = match_token(p, fat_tokens, args); 966 if (token == Opt_err) { 967 if (is_vfat) 968 token = match_token(p, vfat_tokens, args); 969 else 970 token = match_token(p, msdos_tokens, args); 971 } 972 switch (token) { 973 case Opt_check_s: 974 opts->name_check = 's'; 975 break; 976 case Opt_check_r: 977 opts->name_check = 'r'; 978 break; 979 case Opt_check_n: 980 opts->name_check = 'n'; 981 break; 982 case Opt_nocase: 983 if (!is_vfat) 984 opts->nocase = 1; 985 else { 986 /* for backward compatibility */ 987 opts->shortname = VFAT_SFN_DISPLAY_WIN95 988 | VFAT_SFN_CREATE_WIN95; 989 } 990 break; 991 case Opt_quiet: 992 opts->quiet = 1; 993 break; 994 case Opt_showexec: 995 opts->showexec = 1; 996 break; 997 case Opt_debug: 998 *debug = 1; 999 break; 1000 case Opt_immutable: 1001 opts->sys_immutable = 1; 1002 break; 1003 case Opt_uid: 1004 if (match_int(&args[0], &option)) 1005 return 0; 1006 opts->fs_uid = option; 1007 break; 1008 case Opt_gid: 1009 if (match_int(&args[0], &option)) 1010 return 0; 1011 opts->fs_gid = option; 1012 break; 1013 case Opt_umask: 1014 if (match_octal(&args[0], &option)) 1015 return 0; 1016 opts->fs_fmask = opts->fs_dmask = option; 1017 break; 1018 case Opt_dmask: 1019 if (match_octal(&args[0], &option)) 1020 return 0; 1021 opts->fs_dmask = option; 1022 break; 1023 case Opt_fmask: 1024 if (match_octal(&args[0], &option)) 1025 return 0; 1026 opts->fs_fmask = option; 1027 break; 1028 case Opt_codepage: 1029 if (match_int(&args[0], &option)) 1030 return 0; 1031 opts->codepage = option; 1032 break; 1033 case Opt_flush: 1034 opts->flush = 1; 1035 break; 1036 1037 /* msdos specific */ 1038 case Opt_dots: 1039 opts->dotsOK = 1; 1040 break; 1041 case Opt_nodots: 1042 opts->dotsOK = 0; 1043 break; 1044 1045 /* vfat specific */ 1046 case Opt_charset: 1047 if (opts->iocharset != fat_default_iocharset) 1048 kfree(opts->iocharset); 1049 iocharset = match_strdup(&args[0]); 1050 if (!iocharset) 1051 return -ENOMEM; 1052 opts->iocharset = iocharset; 1053 break; 1054 case Opt_shortname_lower: 1055 opts->shortname = VFAT_SFN_DISPLAY_LOWER 1056 | VFAT_SFN_CREATE_WIN95; 1057 break; 1058 case Opt_shortname_win95: 1059 opts->shortname = VFAT_SFN_DISPLAY_WIN95 1060 | VFAT_SFN_CREATE_WIN95; 1061 break; 1062 case Opt_shortname_winnt: 1063 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1064 | VFAT_SFN_CREATE_WINNT; 1065 break; 1066 case Opt_shortname_mixed: 1067 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1068 | VFAT_SFN_CREATE_WIN95; 1069 break; 1070 case Opt_utf8_no: /* 0 or no or false */ 1071 opts->utf8 = 0; 1072 break; 1073 case Opt_utf8_yes: /* empty or 1 or yes or true */ 1074 opts->utf8 = 1; 1075 break; 1076 case Opt_uni_xl_no: /* 0 or no or false */ 1077 opts->unicode_xlate = 0; 1078 break; 1079 case Opt_uni_xl_yes: /* empty or 1 or yes or true */ 1080 opts->unicode_xlate = 1; 1081 break; 1082 case Opt_nonumtail_no: /* 0 or no or false */ 1083 opts->numtail = 1; /* negated option */ 1084 break; 1085 case Opt_nonumtail_yes: /* empty or 1 or yes or true */ 1086 opts->numtail = 0; /* negated option */ 1087 break; 1088 1089 /* obsolete mount options */ 1090 case Opt_obsolate: 1091 printk(KERN_INFO "FAT: \"%s\" option is obsolete, " 1092 "not supported now\n", p); 1093 break; 1094 /* unknown option */ 1095 default: 1096 if (!silent) { 1097 printk(KERN_ERR 1098 "FAT: Unrecognized mount option \"%s\" " 1099 "or missing value\n", p); 1100 } 1101 return -EINVAL; 1102 } 1103 } 1104 /* UTF-8 doesn't provide FAT semantics */ 1105 if (!strcmp(opts->iocharset, "utf8")) { 1106 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset" 1107 " for FAT filesystems, filesystem will be case sensitive!\n"); 1108 } 1109 1110 if (opts->unicode_xlate) 1111 opts->utf8 = 0; 1112 1113 return 0; 1114 } 1115 1116 static int fat_read_root(struct inode *inode) 1117 { 1118 struct super_block *sb = inode->i_sb; 1119 struct msdos_sb_info *sbi = MSDOS_SB(sb); 1120 int error; 1121 1122 MSDOS_I(inode)->i_pos = 0; 1123 inode->i_uid = sbi->options.fs_uid; 1124 inode->i_gid = sbi->options.fs_gid; 1125 inode->i_version++; 1126 inode->i_generation = 0; 1127 inode->i_mode = (S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR; 1128 inode->i_op = sbi->dir_ops; 1129 inode->i_fop = &fat_dir_operations; 1130 if (sbi->fat_bits == 32) { 1131 MSDOS_I(inode)->i_start = sbi->root_cluster; 1132 error = fat_calc_dir_size(inode); 1133 if (error < 0) 1134 return error; 1135 } else { 1136 MSDOS_I(inode)->i_start = 0; 1137 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry); 1138 } 1139 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 1140 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 1141 MSDOS_I(inode)->i_logstart = 0; 1142 MSDOS_I(inode)->mmu_private = inode->i_size; 1143 1144 MSDOS_I(inode)->i_attrs = ATTR_NONE; 1145 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0; 1146 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0; 1147 inode->i_nlink = fat_subdirs(inode)+2; 1148 1149 return 0; 1150 } 1151 1152 /* 1153 * Read the super block of an MS-DOS FS. 1154 */ 1155 int fat_fill_super(struct super_block *sb, void *data, int silent, 1156 const struct inode_operations *fs_dir_inode_ops, int isvfat) 1157 { 1158 struct inode *root_inode = NULL; 1159 struct buffer_head *bh; 1160 struct fat_boot_sector *b; 1161 struct msdos_sb_info *sbi; 1162 u16 logical_sector_size; 1163 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors; 1164 int debug; 1165 unsigned int media; 1166 long error; 1167 char buf[50]; 1168 1169 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL); 1170 if (!sbi) 1171 return -ENOMEM; 1172 sb->s_fs_info = sbi; 1173 1174 sb->s_flags |= MS_NODIRATIME; 1175 sb->s_magic = MSDOS_SUPER_MAGIC; 1176 sb->s_op = &fat_sops; 1177 sb->s_export_op = &fat_export_ops; 1178 sbi->dir_ops = fs_dir_inode_ops; 1179 1180 error = parse_options(data, isvfat, silent, &debug, &sbi->options); 1181 if (error) 1182 goto out_fail; 1183 1184 error = -EIO; 1185 sb_min_blocksize(sb, 512); 1186 bh = sb_bread(sb, 0); 1187 if (bh == NULL) { 1188 printk(KERN_ERR "FAT: unable to read boot sector\n"); 1189 goto out_fail; 1190 } 1191 1192 b = (struct fat_boot_sector *) bh->b_data; 1193 if (!b->reserved) { 1194 if (!silent) 1195 printk(KERN_ERR "FAT: bogus number of reserved sectors\n"); 1196 brelse(bh); 1197 goto out_invalid; 1198 } 1199 if (!b->fats) { 1200 if (!silent) 1201 printk(KERN_ERR "FAT: bogus number of FAT structure\n"); 1202 brelse(bh); 1203 goto out_invalid; 1204 } 1205 1206 /* 1207 * Earlier we checked here that b->secs_track and b->head are nonzero, 1208 * but it turns out valid FAT filesystems can have zero there. 1209 */ 1210 1211 media = b->media; 1212 if (!FAT_VALID_MEDIA(media)) { 1213 if (!silent) 1214 printk(KERN_ERR "FAT: invalid media value (0x%02x)\n", 1215 media); 1216 brelse(bh); 1217 goto out_invalid; 1218 } 1219 logical_sector_size = 1220 le16_to_cpu(get_unaligned((__le16 *)&b->sector_size)); 1221 if (!logical_sector_size 1222 || (logical_sector_size & (logical_sector_size - 1)) 1223 || (logical_sector_size < 512) 1224 || (PAGE_CACHE_SIZE < logical_sector_size)) { 1225 if (!silent) 1226 printk(KERN_ERR "FAT: bogus logical sector size %u\n", 1227 logical_sector_size); 1228 brelse(bh); 1229 goto out_invalid; 1230 } 1231 sbi->sec_per_clus = b->sec_per_clus; 1232 if (!sbi->sec_per_clus 1233 || (sbi->sec_per_clus & (sbi->sec_per_clus - 1))) { 1234 if (!silent) 1235 printk(KERN_ERR "FAT: bogus sectors per cluster %u\n", 1236 sbi->sec_per_clus); 1237 brelse(bh); 1238 goto out_invalid; 1239 } 1240 1241 if (logical_sector_size < sb->s_blocksize) { 1242 printk(KERN_ERR "FAT: logical sector size too small for device" 1243 " (logical sector size = %u)\n", logical_sector_size); 1244 brelse(bh); 1245 goto out_fail; 1246 } 1247 if (logical_sector_size > sb->s_blocksize) { 1248 brelse(bh); 1249 1250 if (!sb_set_blocksize(sb, logical_sector_size)) { 1251 printk(KERN_ERR "FAT: unable to set blocksize %u\n", 1252 logical_sector_size); 1253 goto out_fail; 1254 } 1255 bh = sb_bread(sb, 0); 1256 if (bh == NULL) { 1257 printk(KERN_ERR "FAT: unable to read boot sector" 1258 " (logical sector size = %lu)\n", 1259 sb->s_blocksize); 1260 goto out_fail; 1261 } 1262 b = (struct fat_boot_sector *) bh->b_data; 1263 } 1264 1265 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus; 1266 sbi->cluster_bits = ffs(sbi->cluster_size) - 1; 1267 sbi->fats = b->fats; 1268 sbi->fat_bits = 0; /* Don't know yet */ 1269 sbi->fat_start = le16_to_cpu(b->reserved); 1270 sbi->fat_length = le16_to_cpu(b->fat_length); 1271 sbi->root_cluster = 0; 1272 sbi->free_clusters = -1; /* Don't know yet */ 1273 sbi->prev_free = FAT_START_ENT; 1274 1275 if (!sbi->fat_length && b->fat32_length) { 1276 struct fat_boot_fsinfo *fsinfo; 1277 struct buffer_head *fsinfo_bh; 1278 1279 /* Must be FAT32 */ 1280 sbi->fat_bits = 32; 1281 sbi->fat_length = le32_to_cpu(b->fat32_length); 1282 sbi->root_cluster = le32_to_cpu(b->root_cluster); 1283 1284 sb->s_maxbytes = 0xffffffff; 1285 1286 /* MC - if info_sector is 0, don't multiply by 0 */ 1287 sbi->fsinfo_sector = le16_to_cpu(b->info_sector); 1288 if (sbi->fsinfo_sector == 0) 1289 sbi->fsinfo_sector = 1; 1290 1291 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector); 1292 if (fsinfo_bh == NULL) { 1293 printk(KERN_ERR "FAT: bread failed, FSINFO block" 1294 " (sector = %lu)\n", sbi->fsinfo_sector); 1295 brelse(bh); 1296 goto out_fail; 1297 } 1298 1299 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data; 1300 if (!IS_FSINFO(fsinfo)) { 1301 printk(KERN_WARNING 1302 "FAT: Did not find valid FSINFO signature.\n" 1303 " Found signature1 0x%08x signature2 0x%08x" 1304 " (sector = %lu)\n", 1305 le32_to_cpu(fsinfo->signature1), 1306 le32_to_cpu(fsinfo->signature2), 1307 sbi->fsinfo_sector); 1308 } else { 1309 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters); 1310 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster); 1311 } 1312 1313 brelse(fsinfo_bh); 1314 } 1315 1316 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry); 1317 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1; 1318 1319 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length; 1320 sbi->dir_entries = 1321 le16_to_cpu(get_unaligned((__le16 *)&b->dir_entries)); 1322 if (sbi->dir_entries & (sbi->dir_per_block - 1)) { 1323 if (!silent) 1324 printk(KERN_ERR "FAT: bogus directroy-entries per block" 1325 " (%u)\n", sbi->dir_entries); 1326 brelse(bh); 1327 goto out_invalid; 1328 } 1329 1330 rootdir_sectors = sbi->dir_entries 1331 * sizeof(struct msdos_dir_entry) / sb->s_blocksize; 1332 sbi->data_start = sbi->dir_start + rootdir_sectors; 1333 total_sectors = le16_to_cpu(get_unaligned((__le16 *)&b->sectors)); 1334 if (total_sectors == 0) 1335 total_sectors = le32_to_cpu(b->total_sect); 1336 1337 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus; 1338 1339 if (sbi->fat_bits != 32) 1340 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12; 1341 1342 /* check that FAT table does not overflow */ 1343 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits; 1344 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT); 1345 if (total_clusters > MAX_FAT(sb)) { 1346 if (!silent) 1347 printk(KERN_ERR "FAT: count of clusters too big (%u)\n", 1348 total_clusters); 1349 brelse(bh); 1350 goto out_invalid; 1351 } 1352 1353 sbi->max_cluster = total_clusters + FAT_START_ENT; 1354 /* check the free_clusters, it's not necessarily correct */ 1355 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters) 1356 sbi->free_clusters = -1; 1357 /* check the prev_free, it's not necessarily correct */ 1358 sbi->prev_free %= sbi->max_cluster; 1359 if (sbi->prev_free < FAT_START_ENT) 1360 sbi->prev_free = FAT_START_ENT; 1361 1362 brelse(bh); 1363 1364 /* set up enough so that it can read an inode */ 1365 fat_hash_init(sb); 1366 fat_ent_access_init(sb); 1367 1368 /* 1369 * The low byte of FAT's first entry must have same value with 1370 * media-field. But in real world, too many devices is 1371 * writing wrong value. So, removed that validity check. 1372 * 1373 * if (FAT_FIRST_ENT(sb, media) != first) 1374 */ 1375 1376 error = -EINVAL; 1377 sprintf(buf, "cp%d", sbi->options.codepage); 1378 sbi->nls_disk = load_nls(buf); 1379 if (!sbi->nls_disk) { 1380 printk(KERN_ERR "FAT: codepage %s not found\n", buf); 1381 goto out_fail; 1382 } 1383 1384 /* FIXME: utf8 is using iocharset for upper/lower conversion */ 1385 if (sbi->options.isvfat) { 1386 sbi->nls_io = load_nls(sbi->options.iocharset); 1387 if (!sbi->nls_io) { 1388 printk(KERN_ERR "FAT: IO charset %s not found\n", 1389 sbi->options.iocharset); 1390 goto out_fail; 1391 } 1392 } 1393 1394 error = -ENOMEM; 1395 root_inode = new_inode(sb); 1396 if (!root_inode) 1397 goto out_fail; 1398 root_inode->i_ino = MSDOS_ROOT_INO; 1399 root_inode->i_version = 1; 1400 error = fat_read_root(root_inode); 1401 if (error < 0) 1402 goto out_fail; 1403 error = -ENOMEM; 1404 insert_inode_hash(root_inode); 1405 sb->s_root = d_alloc_root(root_inode); 1406 if (!sb->s_root) { 1407 printk(KERN_ERR "FAT: get root inode failed\n"); 1408 goto out_fail; 1409 } 1410 1411 return 0; 1412 1413 out_invalid: 1414 error = -EINVAL; 1415 if (!silent) 1416 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem" 1417 " on dev %s.\n", sb->s_id); 1418 1419 out_fail: 1420 if (root_inode) 1421 iput(root_inode); 1422 if (sbi->nls_io) 1423 unload_nls(sbi->nls_io); 1424 if (sbi->nls_disk) 1425 unload_nls(sbi->nls_disk); 1426 if (sbi->options.iocharset != fat_default_iocharset) 1427 kfree(sbi->options.iocharset); 1428 sb->s_fs_info = NULL; 1429 kfree(sbi); 1430 return error; 1431 } 1432 1433 EXPORT_SYMBOL_GPL(fat_fill_super); 1434 1435 /* 1436 * helper function for fat_flush_inodes. This writes both the inode 1437 * and the file data blocks, waiting for in flight data blocks before 1438 * the start of the call. It does not wait for any io started 1439 * during the call 1440 */ 1441 static int writeback_inode(struct inode *inode) 1442 { 1443 1444 int ret; 1445 struct address_space *mapping = inode->i_mapping; 1446 struct writeback_control wbc = { 1447 .sync_mode = WB_SYNC_NONE, 1448 .nr_to_write = 0, 1449 }; 1450 /* if we used WB_SYNC_ALL, sync_inode waits for the io for the 1451 * inode to finish. So WB_SYNC_NONE is sent down to sync_inode 1452 * and filemap_fdatawrite is used for the data blocks 1453 */ 1454 ret = sync_inode(inode, &wbc); 1455 if (!ret) 1456 ret = filemap_fdatawrite(mapping); 1457 return ret; 1458 } 1459 1460 /* 1461 * write data and metadata corresponding to i1 and i2. The io is 1462 * started but we do not wait for any of it to finish. 1463 * 1464 * filemap_flush is used for the block device, so if there is a dirty 1465 * page for a block already in flight, we will not wait and start the 1466 * io over again 1467 */ 1468 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2) 1469 { 1470 int ret = 0; 1471 if (!MSDOS_SB(sb)->options.flush) 1472 return 0; 1473 if (i1) 1474 ret = writeback_inode(i1); 1475 if (!ret && i2) 1476 ret = writeback_inode(i2); 1477 if (!ret) { 1478 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping; 1479 ret = filemap_flush(mapping); 1480 } 1481 return ret; 1482 } 1483 EXPORT_SYMBOL_GPL(fat_flush_inodes); 1484 1485 static int __init init_fat_fs(void) 1486 { 1487 int err; 1488 1489 err = fat_cache_init(); 1490 if (err) 1491 return err; 1492 1493 err = fat_init_inodecache(); 1494 if (err) 1495 goto failed; 1496 1497 return 0; 1498 1499 failed: 1500 fat_cache_destroy(); 1501 return err; 1502 } 1503 1504 static void __exit exit_fat_fs(void) 1505 { 1506 fat_cache_destroy(); 1507 fat_destroy_inodecache(); 1508 } 1509 1510 module_init(init_fat_fs) 1511 module_exit(exit_fat_fs) 1512 1513 MODULE_LICENSE("GPL"); 1514