1 /* 2 * linux/fs/fat/inode.c 3 * 4 * Written 1992,1993 by Werner Almesberger 5 * VFAT extensions by Gordon Chaffee, merged with msdos fs by Henrik Storner 6 * Rewritten for the constant inumbers support by Al Viro 7 * 8 * Fixes: 9 * 10 * Max Cohan: Fixed invalid FSINFO offset when info_sector is 0 11 */ 12 13 #include <linux/module.h> 14 #include <linux/init.h> 15 #include <linux/time.h> 16 #include <linux/slab.h> 17 #include <linux/smp_lock.h> 18 #include <linux/seq_file.h> 19 #include <linux/msdos_fs.h> 20 #include <linux/pagemap.h> 21 #include <linux/mpage.h> 22 #include <linux/buffer_head.h> 23 #include <linux/mount.h> 24 #include <linux/vfs.h> 25 #include <linux/parser.h> 26 #include <linux/uio.h> 27 #include <linux/writeback.h> 28 #include <linux/log2.h> 29 #include <asm/unaligned.h> 30 31 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET 32 /* if user don't select VFAT, this is undefined. */ 33 #define CONFIG_FAT_DEFAULT_IOCHARSET "" 34 #endif 35 36 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE; 37 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET; 38 39 40 static int fat_add_cluster(struct inode *inode) 41 { 42 int err, cluster; 43 44 err = fat_alloc_clusters(inode, &cluster, 1); 45 if (err) 46 return err; 47 /* FIXME: this cluster should be added after data of this 48 * cluster is writed */ 49 err = fat_chain_add(inode, cluster, 1); 50 if (err) 51 fat_free_clusters(inode, cluster); 52 return err; 53 } 54 55 static inline int __fat_get_block(struct inode *inode, sector_t iblock, 56 unsigned long *max_blocks, 57 struct buffer_head *bh_result, int create) 58 { 59 struct super_block *sb = inode->i_sb; 60 struct msdos_sb_info *sbi = MSDOS_SB(sb); 61 unsigned long mapped_blocks; 62 sector_t phys; 63 int err, offset; 64 65 err = fat_bmap(inode, iblock, &phys, &mapped_blocks); 66 if (err) 67 return err; 68 if (phys) { 69 map_bh(bh_result, sb, phys); 70 *max_blocks = min(mapped_blocks, *max_blocks); 71 return 0; 72 } 73 if (!create) 74 return 0; 75 76 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) { 77 fat_fs_panic(sb, "corrupted file size (i_pos %lld, %lld)", 78 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private); 79 return -EIO; 80 } 81 82 offset = (unsigned long)iblock & (sbi->sec_per_clus - 1); 83 if (!offset) { 84 /* TODO: multiple cluster allocation would be desirable. */ 85 err = fat_add_cluster(inode); 86 if (err) 87 return err; 88 } 89 /* available blocks on this cluster */ 90 mapped_blocks = sbi->sec_per_clus - offset; 91 92 *max_blocks = min(mapped_blocks, *max_blocks); 93 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits; 94 95 err = fat_bmap(inode, iblock, &phys, &mapped_blocks); 96 if (err) 97 return err; 98 99 BUG_ON(!phys); 100 BUG_ON(*max_blocks != mapped_blocks); 101 set_buffer_new(bh_result); 102 map_bh(bh_result, sb, phys); 103 104 return 0; 105 } 106 107 static int fat_get_block(struct inode *inode, sector_t iblock, 108 struct buffer_head *bh_result, int create) 109 { 110 struct super_block *sb = inode->i_sb; 111 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits; 112 int err; 113 114 err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create); 115 if (err) 116 return err; 117 bh_result->b_size = max_blocks << sb->s_blocksize_bits; 118 return 0; 119 } 120 121 static int fat_writepage(struct page *page, struct writeback_control *wbc) 122 { 123 return block_write_full_page(page, fat_get_block, wbc); 124 } 125 126 static int fat_writepages(struct address_space *mapping, 127 struct writeback_control *wbc) 128 { 129 return mpage_writepages(mapping, wbc, fat_get_block); 130 } 131 132 static int fat_readpage(struct file *file, struct page *page) 133 { 134 return mpage_readpage(page, fat_get_block); 135 } 136 137 static int fat_readpages(struct file *file, struct address_space *mapping, 138 struct list_head *pages, unsigned nr_pages) 139 { 140 return mpage_readpages(mapping, pages, nr_pages, fat_get_block); 141 } 142 143 static int fat_prepare_write(struct file *file, struct page *page, 144 unsigned from, unsigned to) 145 { 146 return cont_prepare_write(page, from, to, fat_get_block, 147 &MSDOS_I(page->mapping->host)->mmu_private); 148 } 149 150 static int fat_commit_write(struct file *file, struct page *page, 151 unsigned from, unsigned to) 152 { 153 struct inode *inode = page->mapping->host; 154 int err = generic_commit_write(file, page, from, to); 155 if (!err && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) { 156 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC; 157 MSDOS_I(inode)->i_attrs |= ATTR_ARCH; 158 mark_inode_dirty(inode); 159 } 160 return err; 161 } 162 163 static ssize_t fat_direct_IO(int rw, struct kiocb *iocb, 164 const struct iovec *iov, 165 loff_t offset, unsigned long nr_segs) 166 { 167 struct file *file = iocb->ki_filp; 168 struct inode *inode = file->f_mapping->host; 169 170 if (rw == WRITE) { 171 /* 172 * FIXME: blockdev_direct_IO() doesn't use ->prepare_write(), 173 * so we need to update the ->mmu_private to block boundary. 174 * 175 * But we must fill the remaining area or hole by nul for 176 * updating ->mmu_private. 177 * 178 * Return 0, and fallback to normal buffered write. 179 */ 180 loff_t size = offset + iov_length(iov, nr_segs); 181 if (MSDOS_I(inode)->mmu_private < size) 182 return 0; 183 } 184 185 /* 186 * FAT need to use the DIO_LOCKING for avoiding the race 187 * condition of fat_get_block() and ->truncate(). 188 */ 189 return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov, 190 offset, nr_segs, fat_get_block, NULL); 191 } 192 193 static sector_t _fat_bmap(struct address_space *mapping, sector_t block) 194 { 195 return generic_block_bmap(mapping, block, fat_get_block); 196 } 197 198 static const struct address_space_operations fat_aops = { 199 .readpage = fat_readpage, 200 .readpages = fat_readpages, 201 .writepage = fat_writepage, 202 .writepages = fat_writepages, 203 .sync_page = block_sync_page, 204 .prepare_write = fat_prepare_write, 205 .commit_write = fat_commit_write, 206 .direct_IO = fat_direct_IO, 207 .bmap = _fat_bmap 208 }; 209 210 /* 211 * New FAT inode stuff. We do the following: 212 * a) i_ino is constant and has nothing with on-disk location. 213 * b) FAT manages its own cache of directory entries. 214 * c) *This* cache is indexed by on-disk location. 215 * d) inode has an associated directory entry, all right, but 216 * it may be unhashed. 217 * e) currently entries are stored within struct inode. That should 218 * change. 219 * f) we deal with races in the following way: 220 * 1. readdir() and lookup() do FAT-dir-cache lookup. 221 * 2. rename() unhashes the F-d-c entry and rehashes it in 222 * a new place. 223 * 3. unlink() and rmdir() unhash F-d-c entry. 224 * 4. fat_write_inode() checks whether the thing is unhashed. 225 * If it is we silently return. If it isn't we do bread(), 226 * check if the location is still valid and retry if it 227 * isn't. Otherwise we do changes. 228 * 5. Spinlock is used to protect hash/unhash/location check/lookup 229 * 6. fat_clear_inode() unhashes the F-d-c entry. 230 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry 231 * and consider negative result as cache miss. 232 */ 233 234 static void fat_hash_init(struct super_block *sb) 235 { 236 struct msdos_sb_info *sbi = MSDOS_SB(sb); 237 int i; 238 239 spin_lock_init(&sbi->inode_hash_lock); 240 for (i = 0; i < FAT_HASH_SIZE; i++) 241 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]); 242 } 243 244 static inline unsigned long fat_hash(struct super_block *sb, loff_t i_pos) 245 { 246 unsigned long tmp = (unsigned long)i_pos | (unsigned long) sb; 247 tmp = tmp + (tmp >> FAT_HASH_BITS) + (tmp >> FAT_HASH_BITS * 2); 248 return tmp & FAT_HASH_MASK; 249 } 250 251 void fat_attach(struct inode *inode, loff_t i_pos) 252 { 253 struct super_block *sb = inode->i_sb; 254 struct msdos_sb_info *sbi = MSDOS_SB(sb); 255 256 spin_lock(&sbi->inode_hash_lock); 257 MSDOS_I(inode)->i_pos = i_pos; 258 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, 259 sbi->inode_hashtable + fat_hash(sb, i_pos)); 260 spin_unlock(&sbi->inode_hash_lock); 261 } 262 263 EXPORT_SYMBOL_GPL(fat_attach); 264 265 void fat_detach(struct inode *inode) 266 { 267 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 268 spin_lock(&sbi->inode_hash_lock); 269 MSDOS_I(inode)->i_pos = 0; 270 hlist_del_init(&MSDOS_I(inode)->i_fat_hash); 271 spin_unlock(&sbi->inode_hash_lock); 272 } 273 274 EXPORT_SYMBOL_GPL(fat_detach); 275 276 struct inode *fat_iget(struct super_block *sb, loff_t i_pos) 277 { 278 struct msdos_sb_info *sbi = MSDOS_SB(sb); 279 struct hlist_head *head = sbi->inode_hashtable + fat_hash(sb, i_pos); 280 struct hlist_node *_p; 281 struct msdos_inode_info *i; 282 struct inode *inode = NULL; 283 284 spin_lock(&sbi->inode_hash_lock); 285 hlist_for_each_entry(i, _p, head, i_fat_hash) { 286 BUG_ON(i->vfs_inode.i_sb != sb); 287 if (i->i_pos != i_pos) 288 continue; 289 inode = igrab(&i->vfs_inode); 290 if (inode) 291 break; 292 } 293 spin_unlock(&sbi->inode_hash_lock); 294 return inode; 295 } 296 297 static int is_exec(unsigned char *extension) 298 { 299 unsigned char *exe_extensions = "EXECOMBAT", *walk; 300 301 for (walk = exe_extensions; *walk; walk += 3) 302 if (!strncmp(extension, walk, 3)) 303 return 1; 304 return 0; 305 } 306 307 static int fat_calc_dir_size(struct inode *inode) 308 { 309 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 310 int ret, fclus, dclus; 311 312 inode->i_size = 0; 313 if (MSDOS_I(inode)->i_start == 0) 314 return 0; 315 316 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); 317 if (ret < 0) 318 return ret; 319 inode->i_size = (fclus + 1) << sbi->cluster_bits; 320 321 return 0; 322 } 323 324 /* doesn't deal with root inode */ 325 static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de) 326 { 327 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 328 int error; 329 330 MSDOS_I(inode)->i_pos = 0; 331 inode->i_uid = sbi->options.fs_uid; 332 inode->i_gid = sbi->options.fs_gid; 333 inode->i_version++; 334 inode->i_generation = get_seconds(); 335 336 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) { 337 inode->i_generation &= ~1; 338 inode->i_mode = MSDOS_MKMODE(de->attr, 339 S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR; 340 inode->i_op = sbi->dir_ops; 341 inode->i_fop = &fat_dir_operations; 342 343 MSDOS_I(inode)->i_start = le16_to_cpu(de->start); 344 if (sbi->fat_bits == 32) 345 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16); 346 347 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 348 error = fat_calc_dir_size(inode); 349 if (error < 0) 350 return error; 351 MSDOS_I(inode)->mmu_private = inode->i_size; 352 353 inode->i_nlink = fat_subdirs(inode); 354 } else { /* not a directory */ 355 inode->i_generation |= 1; 356 inode->i_mode = MSDOS_MKMODE(de->attr, 357 ((sbi->options.showexec && 358 !is_exec(de->ext)) 359 ? S_IRUGO|S_IWUGO : S_IRWXUGO) 360 & ~sbi->options.fs_fmask) | S_IFREG; 361 MSDOS_I(inode)->i_start = le16_to_cpu(de->start); 362 if (sbi->fat_bits == 32) 363 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16); 364 365 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 366 inode->i_size = le32_to_cpu(de->size); 367 inode->i_op = &fat_file_inode_operations; 368 inode->i_fop = &fat_file_operations; 369 inode->i_mapping->a_ops = &fat_aops; 370 MSDOS_I(inode)->mmu_private = inode->i_size; 371 } 372 if (de->attr & ATTR_SYS) { 373 if (sbi->options.sys_immutable) 374 inode->i_flags |= S_IMMUTABLE; 375 } 376 MSDOS_I(inode)->i_attrs = de->attr & ATTR_UNUSED; 377 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 378 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 379 inode->i_mtime.tv_sec = 380 date_dos2unix(le16_to_cpu(de->time), le16_to_cpu(de->date)); 381 inode->i_mtime.tv_nsec = 0; 382 if (sbi->options.isvfat) { 383 int secs = de->ctime_cs / 100; 384 int csecs = de->ctime_cs % 100; 385 inode->i_ctime.tv_sec = 386 date_dos2unix(le16_to_cpu(de->ctime), 387 le16_to_cpu(de->cdate)) + secs; 388 inode->i_ctime.tv_nsec = csecs * 10000000; 389 inode->i_atime.tv_sec = 390 date_dos2unix(0, le16_to_cpu(de->adate)); 391 inode->i_atime.tv_nsec = 0; 392 } else 393 inode->i_ctime = inode->i_atime = inode->i_mtime; 394 395 return 0; 396 } 397 398 struct inode *fat_build_inode(struct super_block *sb, 399 struct msdos_dir_entry *de, loff_t i_pos) 400 { 401 struct inode *inode; 402 int err; 403 404 inode = fat_iget(sb, i_pos); 405 if (inode) 406 goto out; 407 inode = new_inode(sb); 408 if (!inode) { 409 inode = ERR_PTR(-ENOMEM); 410 goto out; 411 } 412 inode->i_ino = iunique(sb, MSDOS_ROOT_INO); 413 inode->i_version = 1; 414 err = fat_fill_inode(inode, de); 415 if (err) { 416 iput(inode); 417 inode = ERR_PTR(err); 418 goto out; 419 } 420 fat_attach(inode, i_pos); 421 insert_inode_hash(inode); 422 out: 423 return inode; 424 } 425 426 EXPORT_SYMBOL_GPL(fat_build_inode); 427 428 static void fat_delete_inode(struct inode *inode) 429 { 430 truncate_inode_pages(&inode->i_data, 0); 431 432 if (!is_bad_inode(inode)) { 433 inode->i_size = 0; 434 fat_truncate(inode); 435 } 436 clear_inode(inode); 437 } 438 439 static void fat_clear_inode(struct inode *inode) 440 { 441 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 442 443 if (is_bad_inode(inode)) 444 return; 445 lock_kernel(); 446 spin_lock(&sbi->inode_hash_lock); 447 fat_cache_inval_inode(inode); 448 hlist_del_init(&MSDOS_I(inode)->i_fat_hash); 449 spin_unlock(&sbi->inode_hash_lock); 450 unlock_kernel(); 451 } 452 453 static void fat_write_super(struct super_block *sb) 454 { 455 sb->s_dirt = 0; 456 457 if (!(sb->s_flags & MS_RDONLY)) 458 fat_clusters_flush(sb); 459 } 460 461 static void fat_put_super(struct super_block *sb) 462 { 463 struct msdos_sb_info *sbi = MSDOS_SB(sb); 464 465 if (sbi->nls_disk) { 466 unload_nls(sbi->nls_disk); 467 sbi->nls_disk = NULL; 468 sbi->options.codepage = fat_default_codepage; 469 } 470 if (sbi->nls_io) { 471 unload_nls(sbi->nls_io); 472 sbi->nls_io = NULL; 473 } 474 if (sbi->options.iocharset != fat_default_iocharset) { 475 kfree(sbi->options.iocharset); 476 sbi->options.iocharset = fat_default_iocharset; 477 } 478 479 sb->s_fs_info = NULL; 480 kfree(sbi); 481 } 482 483 static struct kmem_cache *fat_inode_cachep; 484 485 static struct inode *fat_alloc_inode(struct super_block *sb) 486 { 487 struct msdos_inode_info *ei; 488 ei = kmem_cache_alloc(fat_inode_cachep, GFP_KERNEL); 489 if (!ei) 490 return NULL; 491 return &ei->vfs_inode; 492 } 493 494 static void fat_destroy_inode(struct inode *inode) 495 { 496 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode)); 497 } 498 499 static void init_once(void * foo, struct kmem_cache * cachep, unsigned long flags) 500 { 501 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo; 502 503 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 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 const 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->usefree) 827 seq_puts(m, ",usefree"); 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_usefree, 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_usefree, "usefree"}, 876 {Opt_nocase, "nocase"}, 877 {Opt_quiet, "quiet"}, 878 {Opt_showexec, "showexec"}, 879 {Opt_debug, "debug"}, 880 {Opt_immutable, "sys_immutable"}, 881 {Opt_obsolate, "conv=binary"}, 882 {Opt_obsolate, "conv=text"}, 883 {Opt_obsolate, "conv=auto"}, 884 {Opt_obsolate, "conv=b"}, 885 {Opt_obsolate, "conv=t"}, 886 {Opt_obsolate, "conv=a"}, 887 {Opt_obsolate, "fat=%u"}, 888 {Opt_obsolate, "blocksize=%u"}, 889 {Opt_obsolate, "cvf_format=%20s"}, 890 {Opt_obsolate, "cvf_options=%100s"}, 891 {Opt_obsolate, "posix"}, 892 {Opt_flush, "flush"}, 893 {Opt_err, NULL}, 894 }; 895 static match_table_t msdos_tokens = { 896 {Opt_nodots, "nodots"}, 897 {Opt_nodots, "dotsOK=no"}, 898 {Opt_dots, "dots"}, 899 {Opt_dots, "dotsOK=yes"}, 900 {Opt_err, NULL} 901 }; 902 static match_table_t vfat_tokens = { 903 {Opt_charset, "iocharset=%s"}, 904 {Opt_shortname_lower, "shortname=lower"}, 905 {Opt_shortname_win95, "shortname=win95"}, 906 {Opt_shortname_winnt, "shortname=winnt"}, 907 {Opt_shortname_mixed, "shortname=mixed"}, 908 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */ 909 {Opt_utf8_no, "utf8=no"}, 910 {Opt_utf8_no, "utf8=false"}, 911 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */ 912 {Opt_utf8_yes, "utf8=yes"}, 913 {Opt_utf8_yes, "utf8=true"}, 914 {Opt_utf8_yes, "utf8"}, 915 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */ 916 {Opt_uni_xl_no, "uni_xlate=no"}, 917 {Opt_uni_xl_no, "uni_xlate=false"}, 918 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */ 919 {Opt_uni_xl_yes, "uni_xlate=yes"}, 920 {Opt_uni_xl_yes, "uni_xlate=true"}, 921 {Opt_uni_xl_yes, "uni_xlate"}, 922 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */ 923 {Opt_nonumtail_no, "nonumtail=no"}, 924 {Opt_nonumtail_no, "nonumtail=false"}, 925 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */ 926 {Opt_nonumtail_yes, "nonumtail=yes"}, 927 {Opt_nonumtail_yes, "nonumtail=true"}, 928 {Opt_nonumtail_yes, "nonumtail"}, 929 {Opt_err, NULL} 930 }; 931 932 static int parse_options(char *options, int is_vfat, int silent, int *debug, 933 struct fat_mount_options *opts) 934 { 935 char *p; 936 substring_t args[MAX_OPT_ARGS]; 937 int option; 938 char *iocharset; 939 940 opts->isvfat = is_vfat; 941 942 opts->fs_uid = current->uid; 943 opts->fs_gid = current->gid; 944 opts->fs_fmask = opts->fs_dmask = current->fs->umask; 945 opts->codepage = fat_default_codepage; 946 opts->iocharset = fat_default_iocharset; 947 if (is_vfat) 948 opts->shortname = VFAT_SFN_DISPLAY_LOWER|VFAT_SFN_CREATE_WIN95; 949 else 950 opts->shortname = 0; 951 opts->name_check = 'n'; 952 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0; 953 opts->utf8 = opts->unicode_xlate = 0; 954 opts->numtail = 1; 955 opts->usefree = opts->nocase = 0; 956 *debug = 0; 957 958 if (!options) 959 return 0; 960 961 while ((p = strsep(&options, ",")) != NULL) { 962 int token; 963 if (!*p) 964 continue; 965 966 token = match_token(p, fat_tokens, args); 967 if (token == Opt_err) { 968 if (is_vfat) 969 token = match_token(p, vfat_tokens, args); 970 else 971 token = match_token(p, msdos_tokens, args); 972 } 973 switch (token) { 974 case Opt_check_s: 975 opts->name_check = 's'; 976 break; 977 case Opt_check_r: 978 opts->name_check = 'r'; 979 break; 980 case Opt_check_n: 981 opts->name_check = 'n'; 982 break; 983 case Opt_usefree: 984 opts->usefree = 1; 985 break; 986 case Opt_nocase: 987 if (!is_vfat) 988 opts->nocase = 1; 989 else { 990 /* for backward compatibility */ 991 opts->shortname = VFAT_SFN_DISPLAY_WIN95 992 | VFAT_SFN_CREATE_WIN95; 993 } 994 break; 995 case Opt_quiet: 996 opts->quiet = 1; 997 break; 998 case Opt_showexec: 999 opts->showexec = 1; 1000 break; 1001 case Opt_debug: 1002 *debug = 1; 1003 break; 1004 case Opt_immutable: 1005 opts->sys_immutable = 1; 1006 break; 1007 case Opt_uid: 1008 if (match_int(&args[0], &option)) 1009 return 0; 1010 opts->fs_uid = option; 1011 break; 1012 case Opt_gid: 1013 if (match_int(&args[0], &option)) 1014 return 0; 1015 opts->fs_gid = option; 1016 break; 1017 case Opt_umask: 1018 if (match_octal(&args[0], &option)) 1019 return 0; 1020 opts->fs_fmask = opts->fs_dmask = option; 1021 break; 1022 case Opt_dmask: 1023 if (match_octal(&args[0], &option)) 1024 return 0; 1025 opts->fs_dmask = option; 1026 break; 1027 case Opt_fmask: 1028 if (match_octal(&args[0], &option)) 1029 return 0; 1030 opts->fs_fmask = option; 1031 break; 1032 case Opt_codepage: 1033 if (match_int(&args[0], &option)) 1034 return 0; 1035 opts->codepage = option; 1036 break; 1037 case Opt_flush: 1038 opts->flush = 1; 1039 break; 1040 1041 /* msdos specific */ 1042 case Opt_dots: 1043 opts->dotsOK = 1; 1044 break; 1045 case Opt_nodots: 1046 opts->dotsOK = 0; 1047 break; 1048 1049 /* vfat specific */ 1050 case Opt_charset: 1051 if (opts->iocharset != fat_default_iocharset) 1052 kfree(opts->iocharset); 1053 iocharset = match_strdup(&args[0]); 1054 if (!iocharset) 1055 return -ENOMEM; 1056 opts->iocharset = iocharset; 1057 break; 1058 case Opt_shortname_lower: 1059 opts->shortname = VFAT_SFN_DISPLAY_LOWER 1060 | VFAT_SFN_CREATE_WIN95; 1061 break; 1062 case Opt_shortname_win95: 1063 opts->shortname = VFAT_SFN_DISPLAY_WIN95 1064 | VFAT_SFN_CREATE_WIN95; 1065 break; 1066 case Opt_shortname_winnt: 1067 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1068 | VFAT_SFN_CREATE_WINNT; 1069 break; 1070 case Opt_shortname_mixed: 1071 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1072 | VFAT_SFN_CREATE_WIN95; 1073 break; 1074 case Opt_utf8_no: /* 0 or no or false */ 1075 opts->utf8 = 0; 1076 break; 1077 case Opt_utf8_yes: /* empty or 1 or yes or true */ 1078 opts->utf8 = 1; 1079 break; 1080 case Opt_uni_xl_no: /* 0 or no or false */ 1081 opts->unicode_xlate = 0; 1082 break; 1083 case Opt_uni_xl_yes: /* empty or 1 or yes or true */ 1084 opts->unicode_xlate = 1; 1085 break; 1086 case Opt_nonumtail_no: /* 0 or no or false */ 1087 opts->numtail = 1; /* negated option */ 1088 break; 1089 case Opt_nonumtail_yes: /* empty or 1 or yes or true */ 1090 opts->numtail = 0; /* negated option */ 1091 break; 1092 1093 /* obsolete mount options */ 1094 case Opt_obsolate: 1095 printk(KERN_INFO "FAT: \"%s\" option is obsolete, " 1096 "not supported now\n", p); 1097 break; 1098 /* unknown option */ 1099 default: 1100 if (!silent) { 1101 printk(KERN_ERR 1102 "FAT: Unrecognized mount option \"%s\" " 1103 "or missing value\n", p); 1104 } 1105 return -EINVAL; 1106 } 1107 } 1108 /* UTF-8 doesn't provide FAT semantics */ 1109 if (!strcmp(opts->iocharset, "utf8")) { 1110 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset" 1111 " for FAT filesystems, filesystem will be case sensitive!\n"); 1112 } 1113 1114 if (opts->unicode_xlate) 1115 opts->utf8 = 0; 1116 1117 return 0; 1118 } 1119 1120 static int fat_read_root(struct inode *inode) 1121 { 1122 struct super_block *sb = inode->i_sb; 1123 struct msdos_sb_info *sbi = MSDOS_SB(sb); 1124 int error; 1125 1126 MSDOS_I(inode)->i_pos = 0; 1127 inode->i_uid = sbi->options.fs_uid; 1128 inode->i_gid = sbi->options.fs_gid; 1129 inode->i_version++; 1130 inode->i_generation = 0; 1131 inode->i_mode = (S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR; 1132 inode->i_op = sbi->dir_ops; 1133 inode->i_fop = &fat_dir_operations; 1134 if (sbi->fat_bits == 32) { 1135 MSDOS_I(inode)->i_start = sbi->root_cluster; 1136 error = fat_calc_dir_size(inode); 1137 if (error < 0) 1138 return error; 1139 } else { 1140 MSDOS_I(inode)->i_start = 0; 1141 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry); 1142 } 1143 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 1144 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 1145 MSDOS_I(inode)->i_logstart = 0; 1146 MSDOS_I(inode)->mmu_private = inode->i_size; 1147 1148 MSDOS_I(inode)->i_attrs = ATTR_NONE; 1149 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0; 1150 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0; 1151 inode->i_nlink = fat_subdirs(inode)+2; 1152 1153 return 0; 1154 } 1155 1156 /* 1157 * Read the super block of an MS-DOS FS. 1158 */ 1159 int fat_fill_super(struct super_block *sb, void *data, int silent, 1160 const struct inode_operations *fs_dir_inode_ops, int isvfat) 1161 { 1162 struct inode *root_inode = NULL; 1163 struct buffer_head *bh; 1164 struct fat_boot_sector *b; 1165 struct msdos_sb_info *sbi; 1166 u16 logical_sector_size; 1167 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors; 1168 int debug; 1169 unsigned int media; 1170 long error; 1171 char buf[50]; 1172 1173 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL); 1174 if (!sbi) 1175 return -ENOMEM; 1176 sb->s_fs_info = sbi; 1177 1178 sb->s_flags |= MS_NODIRATIME; 1179 sb->s_magic = MSDOS_SUPER_MAGIC; 1180 sb->s_op = &fat_sops; 1181 sb->s_export_op = &fat_export_ops; 1182 sbi->dir_ops = fs_dir_inode_ops; 1183 1184 error = parse_options(data, isvfat, silent, &debug, &sbi->options); 1185 if (error) 1186 goto out_fail; 1187 1188 error = -EIO; 1189 sb_min_blocksize(sb, 512); 1190 bh = sb_bread(sb, 0); 1191 if (bh == NULL) { 1192 printk(KERN_ERR "FAT: unable to read boot sector\n"); 1193 goto out_fail; 1194 } 1195 1196 b = (struct fat_boot_sector *) bh->b_data; 1197 if (!b->reserved) { 1198 if (!silent) 1199 printk(KERN_ERR "FAT: bogus number of reserved sectors\n"); 1200 brelse(bh); 1201 goto out_invalid; 1202 } 1203 if (!b->fats) { 1204 if (!silent) 1205 printk(KERN_ERR "FAT: bogus number of FAT structure\n"); 1206 brelse(bh); 1207 goto out_invalid; 1208 } 1209 1210 /* 1211 * Earlier we checked here that b->secs_track and b->head are nonzero, 1212 * but it turns out valid FAT filesystems can have zero there. 1213 */ 1214 1215 media = b->media; 1216 if (!FAT_VALID_MEDIA(media)) { 1217 if (!silent) 1218 printk(KERN_ERR "FAT: invalid media value (0x%02x)\n", 1219 media); 1220 brelse(bh); 1221 goto out_invalid; 1222 } 1223 logical_sector_size = 1224 le16_to_cpu(get_unaligned((__le16 *)&b->sector_size)); 1225 if (!is_power_of_2(logical_sector_size) 1226 || (logical_sector_size < 512) 1227 || (PAGE_CACHE_SIZE < logical_sector_size)) { 1228 if (!silent) 1229 printk(KERN_ERR "FAT: bogus logical sector size %u\n", 1230 logical_sector_size); 1231 brelse(bh); 1232 goto out_invalid; 1233 } 1234 sbi->sec_per_clus = b->sec_per_clus; 1235 if (!is_power_of_2(sbi->sec_per_clus)) { 1236 if (!silent) 1237 printk(KERN_ERR "FAT: bogus sectors per cluster %u\n", 1238 sbi->sec_per_clus); 1239 brelse(bh); 1240 goto out_invalid; 1241 } 1242 1243 if (logical_sector_size < sb->s_blocksize) { 1244 printk(KERN_ERR "FAT: logical sector size too small for device" 1245 " (logical sector size = %u)\n", logical_sector_size); 1246 brelse(bh); 1247 goto out_fail; 1248 } 1249 if (logical_sector_size > sb->s_blocksize) { 1250 brelse(bh); 1251 1252 if (!sb_set_blocksize(sb, logical_sector_size)) { 1253 printk(KERN_ERR "FAT: unable to set blocksize %u\n", 1254 logical_sector_size); 1255 goto out_fail; 1256 } 1257 bh = sb_bread(sb, 0); 1258 if (bh == NULL) { 1259 printk(KERN_ERR "FAT: unable to read boot sector" 1260 " (logical sector size = %lu)\n", 1261 sb->s_blocksize); 1262 goto out_fail; 1263 } 1264 b = (struct fat_boot_sector *) bh->b_data; 1265 } 1266 1267 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus; 1268 sbi->cluster_bits = ffs(sbi->cluster_size) - 1; 1269 sbi->fats = b->fats; 1270 sbi->fat_bits = 0; /* Don't know yet */ 1271 sbi->fat_start = le16_to_cpu(b->reserved); 1272 sbi->fat_length = le16_to_cpu(b->fat_length); 1273 sbi->root_cluster = 0; 1274 sbi->free_clusters = -1; /* Don't know yet */ 1275 sbi->prev_free = FAT_START_ENT; 1276 1277 if (!sbi->fat_length && b->fat32_length) { 1278 struct fat_boot_fsinfo *fsinfo; 1279 struct buffer_head *fsinfo_bh; 1280 1281 /* Must be FAT32 */ 1282 sbi->fat_bits = 32; 1283 sbi->fat_length = le32_to_cpu(b->fat32_length); 1284 sbi->root_cluster = le32_to_cpu(b->root_cluster); 1285 1286 sb->s_maxbytes = 0xffffffff; 1287 1288 /* MC - if info_sector is 0, don't multiply by 0 */ 1289 sbi->fsinfo_sector = le16_to_cpu(b->info_sector); 1290 if (sbi->fsinfo_sector == 0) 1291 sbi->fsinfo_sector = 1; 1292 1293 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector); 1294 if (fsinfo_bh == NULL) { 1295 printk(KERN_ERR "FAT: bread failed, FSINFO block" 1296 " (sector = %lu)\n", sbi->fsinfo_sector); 1297 brelse(bh); 1298 goto out_fail; 1299 } 1300 1301 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data; 1302 if (!IS_FSINFO(fsinfo)) { 1303 printk(KERN_WARNING 1304 "FAT: Did not find valid FSINFO signature.\n" 1305 " Found signature1 0x%08x signature2 0x%08x" 1306 " (sector = %lu)\n", 1307 le32_to_cpu(fsinfo->signature1), 1308 le32_to_cpu(fsinfo->signature2), 1309 sbi->fsinfo_sector); 1310 } else { 1311 if (sbi->options.usefree) 1312 sbi->free_clusters = 1313 le32_to_cpu(fsinfo->free_clusters); 1314 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster); 1315 } 1316 1317 brelse(fsinfo_bh); 1318 } 1319 1320 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry); 1321 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1; 1322 1323 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length; 1324 sbi->dir_entries = 1325 le16_to_cpu(get_unaligned((__le16 *)&b->dir_entries)); 1326 if (sbi->dir_entries & (sbi->dir_per_block - 1)) { 1327 if (!silent) 1328 printk(KERN_ERR "FAT: bogus directroy-entries per block" 1329 " (%u)\n", sbi->dir_entries); 1330 brelse(bh); 1331 goto out_invalid; 1332 } 1333 1334 rootdir_sectors = sbi->dir_entries 1335 * sizeof(struct msdos_dir_entry) / sb->s_blocksize; 1336 sbi->data_start = sbi->dir_start + rootdir_sectors; 1337 total_sectors = le16_to_cpu(get_unaligned((__le16 *)&b->sectors)); 1338 if (total_sectors == 0) 1339 total_sectors = le32_to_cpu(b->total_sect); 1340 1341 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus; 1342 1343 if (sbi->fat_bits != 32) 1344 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12; 1345 1346 /* check that FAT table does not overflow */ 1347 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits; 1348 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT); 1349 if (total_clusters > MAX_FAT(sb)) { 1350 if (!silent) 1351 printk(KERN_ERR "FAT: count of clusters too big (%u)\n", 1352 total_clusters); 1353 brelse(bh); 1354 goto out_invalid; 1355 } 1356 1357 sbi->max_cluster = total_clusters + FAT_START_ENT; 1358 /* check the free_clusters, it's not necessarily correct */ 1359 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters) 1360 sbi->free_clusters = -1; 1361 /* check the prev_free, it's not necessarily correct */ 1362 sbi->prev_free %= sbi->max_cluster; 1363 if (sbi->prev_free < FAT_START_ENT) 1364 sbi->prev_free = FAT_START_ENT; 1365 1366 brelse(bh); 1367 1368 /* set up enough so that it can read an inode */ 1369 fat_hash_init(sb); 1370 fat_ent_access_init(sb); 1371 1372 /* 1373 * The low byte of FAT's first entry must have same value with 1374 * media-field. But in real world, too many devices is 1375 * writing wrong value. So, removed that validity check. 1376 * 1377 * if (FAT_FIRST_ENT(sb, media) != first) 1378 */ 1379 1380 error = -EINVAL; 1381 sprintf(buf, "cp%d", sbi->options.codepage); 1382 sbi->nls_disk = load_nls(buf); 1383 if (!sbi->nls_disk) { 1384 printk(KERN_ERR "FAT: codepage %s not found\n", buf); 1385 goto out_fail; 1386 } 1387 1388 /* FIXME: utf8 is using iocharset for upper/lower conversion */ 1389 if (sbi->options.isvfat) { 1390 sbi->nls_io = load_nls(sbi->options.iocharset); 1391 if (!sbi->nls_io) { 1392 printk(KERN_ERR "FAT: IO charset %s not found\n", 1393 sbi->options.iocharset); 1394 goto out_fail; 1395 } 1396 } 1397 1398 error = -ENOMEM; 1399 root_inode = new_inode(sb); 1400 if (!root_inode) 1401 goto out_fail; 1402 root_inode->i_ino = MSDOS_ROOT_INO; 1403 root_inode->i_version = 1; 1404 error = fat_read_root(root_inode); 1405 if (error < 0) 1406 goto out_fail; 1407 error = -ENOMEM; 1408 insert_inode_hash(root_inode); 1409 sb->s_root = d_alloc_root(root_inode); 1410 if (!sb->s_root) { 1411 printk(KERN_ERR "FAT: get root inode failed\n"); 1412 goto out_fail; 1413 } 1414 1415 return 0; 1416 1417 out_invalid: 1418 error = -EINVAL; 1419 if (!silent) 1420 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem" 1421 " on dev %s.\n", sb->s_id); 1422 1423 out_fail: 1424 if (root_inode) 1425 iput(root_inode); 1426 if (sbi->nls_io) 1427 unload_nls(sbi->nls_io); 1428 if (sbi->nls_disk) 1429 unload_nls(sbi->nls_disk); 1430 if (sbi->options.iocharset != fat_default_iocharset) 1431 kfree(sbi->options.iocharset); 1432 sb->s_fs_info = NULL; 1433 kfree(sbi); 1434 return error; 1435 } 1436 1437 EXPORT_SYMBOL_GPL(fat_fill_super); 1438 1439 /* 1440 * helper function for fat_flush_inodes. This writes both the inode 1441 * and the file data blocks, waiting for in flight data blocks before 1442 * the start of the call. It does not wait for any io started 1443 * during the call 1444 */ 1445 static int writeback_inode(struct inode *inode) 1446 { 1447 1448 int ret; 1449 struct address_space *mapping = inode->i_mapping; 1450 struct writeback_control wbc = { 1451 .sync_mode = WB_SYNC_NONE, 1452 .nr_to_write = 0, 1453 }; 1454 /* if we used WB_SYNC_ALL, sync_inode waits for the io for the 1455 * inode to finish. So WB_SYNC_NONE is sent down to sync_inode 1456 * and filemap_fdatawrite is used for the data blocks 1457 */ 1458 ret = sync_inode(inode, &wbc); 1459 if (!ret) 1460 ret = filemap_fdatawrite(mapping); 1461 return ret; 1462 } 1463 1464 /* 1465 * write data and metadata corresponding to i1 and i2. The io is 1466 * started but we do not wait for any of it to finish. 1467 * 1468 * filemap_flush is used for the block device, so if there is a dirty 1469 * page for a block already in flight, we will not wait and start the 1470 * io over again 1471 */ 1472 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2) 1473 { 1474 int ret = 0; 1475 if (!MSDOS_SB(sb)->options.flush) 1476 return 0; 1477 if (i1) 1478 ret = writeback_inode(i1); 1479 if (!ret && i2) 1480 ret = writeback_inode(i2); 1481 if (!ret) { 1482 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping; 1483 ret = filemap_flush(mapping); 1484 } 1485 return ret; 1486 } 1487 EXPORT_SYMBOL_GPL(fat_flush_inodes); 1488 1489 static int __init init_fat_fs(void) 1490 { 1491 int err; 1492 1493 err = fat_cache_init(); 1494 if (err) 1495 return err; 1496 1497 err = fat_init_inodecache(); 1498 if (err) 1499 goto failed; 1500 1501 return 0; 1502 1503 failed: 1504 fat_cache_destroy(); 1505 return err; 1506 } 1507 1508 static void __exit exit_fat_fs(void) 1509 { 1510 fat_cache_destroy(); 1511 fat_destroy_inodecache(); 1512 } 1513 1514 module_init(init_fat_fs) 1515 module_exit(exit_fat_fs) 1516 1517 MODULE_LICENSE("GPL"); 1518