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/exportfs.h> 24 #include <linux/mount.h> 25 #include <linux/vfs.h> 26 #include <linux/parser.h> 27 #include <linux/uio.h> 28 #include <linux/writeback.h> 29 #include <linux/log2.h> 30 #include <asm/unaligned.h> 31 32 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET 33 /* if user don't select VFAT, this is undefined. */ 34 #define CONFIG_FAT_DEFAULT_IOCHARSET "" 35 #endif 36 37 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE; 38 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET; 39 40 41 static int fat_add_cluster(struct inode *inode) 42 { 43 int err, cluster; 44 45 err = fat_alloc_clusters(inode, &cluster, 1); 46 if (err) 47 return err; 48 /* FIXME: this cluster should be added after data of this 49 * cluster is writed */ 50 err = fat_chain_add(inode, cluster, 1); 51 if (err) 52 fat_free_clusters(inode, cluster); 53 return err; 54 } 55 56 static inline int __fat_get_block(struct inode *inode, sector_t iblock, 57 unsigned long *max_blocks, 58 struct buffer_head *bh_result, int create) 59 { 60 struct super_block *sb = inode->i_sb; 61 struct msdos_sb_info *sbi = MSDOS_SB(sb); 62 unsigned long mapped_blocks; 63 sector_t phys; 64 int err, offset; 65 66 err = fat_bmap(inode, iblock, &phys, &mapped_blocks); 67 if (err) 68 return err; 69 if (phys) { 70 map_bh(bh_result, sb, phys); 71 *max_blocks = min(mapped_blocks, *max_blocks); 72 return 0; 73 } 74 if (!create) 75 return 0; 76 77 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) { 78 fat_fs_panic(sb, "corrupted file size (i_pos %lld, %lld)", 79 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private); 80 return -EIO; 81 } 82 83 offset = (unsigned long)iblock & (sbi->sec_per_clus - 1); 84 if (!offset) { 85 /* TODO: multiple cluster allocation would be desirable. */ 86 err = fat_add_cluster(inode); 87 if (err) 88 return err; 89 } 90 /* available blocks on this cluster */ 91 mapped_blocks = sbi->sec_per_clus - offset; 92 93 *max_blocks = min(mapped_blocks, *max_blocks); 94 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits; 95 96 err = fat_bmap(inode, iblock, &phys, &mapped_blocks); 97 if (err) 98 return err; 99 100 BUG_ON(!phys); 101 BUG_ON(*max_blocks != mapped_blocks); 102 set_buffer_new(bh_result); 103 map_bh(bh_result, sb, phys); 104 105 return 0; 106 } 107 108 static int fat_get_block(struct inode *inode, sector_t iblock, 109 struct buffer_head *bh_result, int create) 110 { 111 struct super_block *sb = inode->i_sb; 112 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits; 113 int err; 114 115 err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create); 116 if (err) 117 return err; 118 bh_result->b_size = max_blocks << sb->s_blocksize_bits; 119 return 0; 120 } 121 122 static int fat_writepage(struct page *page, struct writeback_control *wbc) 123 { 124 return block_write_full_page(page, fat_get_block, wbc); 125 } 126 127 static int fat_writepages(struct address_space *mapping, 128 struct writeback_control *wbc) 129 { 130 return mpage_writepages(mapping, wbc, fat_get_block); 131 } 132 133 static int fat_readpage(struct file *file, struct page *page) 134 { 135 return mpage_readpage(page, fat_get_block); 136 } 137 138 static int fat_readpages(struct file *file, struct address_space *mapping, 139 struct list_head *pages, unsigned nr_pages) 140 { 141 return mpage_readpages(mapping, pages, nr_pages, fat_get_block); 142 } 143 144 static int fat_write_begin(struct file *file, struct address_space *mapping, 145 loff_t pos, unsigned len, unsigned flags, 146 struct page **pagep, void **fsdata) 147 { 148 *pagep = NULL; 149 return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata, 150 fat_get_block, 151 &MSDOS_I(mapping->host)->mmu_private); 152 } 153 154 static int fat_write_end(struct file *file, struct address_space *mapping, 155 loff_t pos, unsigned len, unsigned copied, 156 struct page *pagep, void *fsdata) 157 { 158 struct inode *inode = mapping->host; 159 int err; 160 err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata); 161 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) { 162 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC; 163 MSDOS_I(inode)->i_attrs |= ATTR_ARCH; 164 mark_inode_dirty(inode); 165 } 166 return err; 167 } 168 169 static ssize_t fat_direct_IO(int rw, struct kiocb *iocb, 170 const struct iovec *iov, 171 loff_t offset, unsigned long nr_segs) 172 { 173 struct file *file = iocb->ki_filp; 174 struct inode *inode = file->f_mapping->host; 175 176 if (rw == WRITE) { 177 /* 178 * FIXME: blockdev_direct_IO() doesn't use ->prepare_write(), 179 * so we need to update the ->mmu_private to block boundary. 180 * 181 * But we must fill the remaining area or hole by nul for 182 * updating ->mmu_private. 183 * 184 * Return 0, and fallback to normal buffered write. 185 */ 186 loff_t size = offset + iov_length(iov, nr_segs); 187 if (MSDOS_I(inode)->mmu_private < size) 188 return 0; 189 } 190 191 /* 192 * FAT need to use the DIO_LOCKING for avoiding the race 193 * condition of fat_get_block() and ->truncate(). 194 */ 195 return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov, 196 offset, nr_segs, fat_get_block, NULL); 197 } 198 199 static sector_t _fat_bmap(struct address_space *mapping, sector_t block) 200 { 201 return generic_block_bmap(mapping, block, fat_get_block); 202 } 203 204 static const struct address_space_operations fat_aops = { 205 .readpage = fat_readpage, 206 .readpages = fat_readpages, 207 .writepage = fat_writepage, 208 .writepages = fat_writepages, 209 .sync_page = block_sync_page, 210 .write_begin = fat_write_begin, 211 .write_end = fat_write_end, 212 .direct_IO = fat_direct_IO, 213 .bmap = _fat_bmap 214 }; 215 216 /* 217 * New FAT inode stuff. We do the following: 218 * a) i_ino is constant and has nothing with on-disk location. 219 * b) FAT manages its own cache of directory entries. 220 * c) *This* cache is indexed by on-disk location. 221 * d) inode has an associated directory entry, all right, but 222 * it may be unhashed. 223 * e) currently entries are stored within struct inode. That should 224 * change. 225 * f) we deal with races in the following way: 226 * 1. readdir() and lookup() do FAT-dir-cache lookup. 227 * 2. rename() unhashes the F-d-c entry and rehashes it in 228 * a new place. 229 * 3. unlink() and rmdir() unhash F-d-c entry. 230 * 4. fat_write_inode() checks whether the thing is unhashed. 231 * If it is we silently return. If it isn't we do bread(), 232 * check if the location is still valid and retry if it 233 * isn't. Otherwise we do changes. 234 * 5. Spinlock is used to protect hash/unhash/location check/lookup 235 * 6. fat_clear_inode() unhashes the F-d-c entry. 236 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry 237 * and consider negative result as cache miss. 238 */ 239 240 static void fat_hash_init(struct super_block *sb) 241 { 242 struct msdos_sb_info *sbi = MSDOS_SB(sb); 243 int i; 244 245 spin_lock_init(&sbi->inode_hash_lock); 246 for (i = 0; i < FAT_HASH_SIZE; i++) 247 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]); 248 } 249 250 static inline unsigned long fat_hash(struct super_block *sb, loff_t i_pos) 251 { 252 unsigned long tmp = (unsigned long)i_pos | (unsigned long) sb; 253 tmp = tmp + (tmp >> FAT_HASH_BITS) + (tmp >> FAT_HASH_BITS * 2); 254 return tmp & FAT_HASH_MASK; 255 } 256 257 void fat_attach(struct inode *inode, loff_t i_pos) 258 { 259 struct super_block *sb = inode->i_sb; 260 struct msdos_sb_info *sbi = MSDOS_SB(sb); 261 262 spin_lock(&sbi->inode_hash_lock); 263 MSDOS_I(inode)->i_pos = i_pos; 264 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, 265 sbi->inode_hashtable + fat_hash(sb, i_pos)); 266 spin_unlock(&sbi->inode_hash_lock); 267 } 268 269 EXPORT_SYMBOL_GPL(fat_attach); 270 271 void fat_detach(struct inode *inode) 272 { 273 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 274 spin_lock(&sbi->inode_hash_lock); 275 MSDOS_I(inode)->i_pos = 0; 276 hlist_del_init(&MSDOS_I(inode)->i_fat_hash); 277 spin_unlock(&sbi->inode_hash_lock); 278 } 279 280 EXPORT_SYMBOL_GPL(fat_detach); 281 282 struct inode *fat_iget(struct super_block *sb, loff_t i_pos) 283 { 284 struct msdos_sb_info *sbi = MSDOS_SB(sb); 285 struct hlist_head *head = sbi->inode_hashtable + fat_hash(sb, i_pos); 286 struct hlist_node *_p; 287 struct msdos_inode_info *i; 288 struct inode *inode = NULL; 289 290 spin_lock(&sbi->inode_hash_lock); 291 hlist_for_each_entry(i, _p, head, i_fat_hash) { 292 BUG_ON(i->vfs_inode.i_sb != sb); 293 if (i->i_pos != i_pos) 294 continue; 295 inode = igrab(&i->vfs_inode); 296 if (inode) 297 break; 298 } 299 spin_unlock(&sbi->inode_hash_lock); 300 return inode; 301 } 302 303 static int is_exec(unsigned char *extension) 304 { 305 unsigned char *exe_extensions = "EXECOMBAT", *walk; 306 307 for (walk = exe_extensions; *walk; walk += 3) 308 if (!strncmp(extension, walk, 3)) 309 return 1; 310 return 0; 311 } 312 313 static int fat_calc_dir_size(struct inode *inode) 314 { 315 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 316 int ret, fclus, dclus; 317 318 inode->i_size = 0; 319 if (MSDOS_I(inode)->i_start == 0) 320 return 0; 321 322 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); 323 if (ret < 0) 324 return ret; 325 inode->i_size = (fclus + 1) << sbi->cluster_bits; 326 327 return 0; 328 } 329 330 /* doesn't deal with root inode */ 331 static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de) 332 { 333 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 334 int error; 335 336 MSDOS_I(inode)->i_pos = 0; 337 inode->i_uid = sbi->options.fs_uid; 338 inode->i_gid = sbi->options.fs_gid; 339 inode->i_version++; 340 inode->i_generation = get_seconds(); 341 342 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) { 343 inode->i_generation &= ~1; 344 inode->i_mode = MSDOS_MKMODE(de->attr, 345 S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR; 346 inode->i_op = sbi->dir_ops; 347 inode->i_fop = &fat_dir_operations; 348 349 MSDOS_I(inode)->i_start = le16_to_cpu(de->start); 350 if (sbi->fat_bits == 32) 351 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16); 352 353 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 354 error = fat_calc_dir_size(inode); 355 if (error < 0) 356 return error; 357 MSDOS_I(inode)->mmu_private = inode->i_size; 358 359 inode->i_nlink = fat_subdirs(inode); 360 } else { /* not a directory */ 361 inode->i_generation |= 1; 362 inode->i_mode = MSDOS_MKMODE(de->attr, 363 ((sbi->options.showexec && !is_exec(de->name + 8)) 364 ? S_IRUGO|S_IWUGO : S_IRWXUGO) 365 & ~sbi->options.fs_fmask) | S_IFREG; 366 MSDOS_I(inode)->i_start = le16_to_cpu(de->start); 367 if (sbi->fat_bits == 32) 368 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16); 369 370 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 371 inode->i_size = le32_to_cpu(de->size); 372 inode->i_op = &fat_file_inode_operations; 373 inode->i_fop = &fat_file_operations; 374 inode->i_mapping->a_ops = &fat_aops; 375 MSDOS_I(inode)->mmu_private = inode->i_size; 376 } 377 if (de->attr & ATTR_SYS) { 378 if (sbi->options.sys_immutable) 379 inode->i_flags |= S_IMMUTABLE; 380 } 381 MSDOS_I(inode)->i_attrs = de->attr & ATTR_UNUSED; 382 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 383 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 384 inode->i_mtime.tv_sec = 385 date_dos2unix(le16_to_cpu(de->time), le16_to_cpu(de->date)); 386 inode->i_mtime.tv_nsec = 0; 387 if (sbi->options.isvfat) { 388 int secs = de->ctime_cs / 100; 389 int csecs = de->ctime_cs % 100; 390 inode->i_ctime.tv_sec = 391 date_dos2unix(le16_to_cpu(de->ctime), 392 le16_to_cpu(de->cdate)) + secs; 393 inode->i_ctime.tv_nsec = csecs * 10000000; 394 inode->i_atime.tv_sec = 395 date_dos2unix(0, le16_to_cpu(de->adate)); 396 inode->i_atime.tv_nsec = 0; 397 } else 398 inode->i_ctime = inode->i_atime = inode->i_mtime; 399 400 return 0; 401 } 402 403 struct inode *fat_build_inode(struct super_block *sb, 404 struct msdos_dir_entry *de, loff_t i_pos) 405 { 406 struct inode *inode; 407 int err; 408 409 inode = fat_iget(sb, i_pos); 410 if (inode) 411 goto out; 412 inode = new_inode(sb); 413 if (!inode) { 414 inode = ERR_PTR(-ENOMEM); 415 goto out; 416 } 417 inode->i_ino = iunique(sb, MSDOS_ROOT_INO); 418 inode->i_version = 1; 419 err = fat_fill_inode(inode, de); 420 if (err) { 421 iput(inode); 422 inode = ERR_PTR(err); 423 goto out; 424 } 425 fat_attach(inode, i_pos); 426 insert_inode_hash(inode); 427 out: 428 return inode; 429 } 430 431 EXPORT_SYMBOL_GPL(fat_build_inode); 432 433 static void fat_delete_inode(struct inode *inode) 434 { 435 truncate_inode_pages(&inode->i_data, 0); 436 437 if (!is_bad_inode(inode)) { 438 inode->i_size = 0; 439 fat_truncate(inode); 440 } 441 clear_inode(inode); 442 } 443 444 static void fat_clear_inode(struct inode *inode) 445 { 446 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 447 448 if (is_bad_inode(inode)) 449 return; 450 lock_kernel(); 451 spin_lock(&sbi->inode_hash_lock); 452 fat_cache_inval_inode(inode); 453 hlist_del_init(&MSDOS_I(inode)->i_fat_hash); 454 spin_unlock(&sbi->inode_hash_lock); 455 unlock_kernel(); 456 } 457 458 static void fat_write_super(struct super_block *sb) 459 { 460 sb->s_dirt = 0; 461 462 if (!(sb->s_flags & MS_RDONLY)) 463 fat_clusters_flush(sb); 464 } 465 466 static void fat_put_super(struct super_block *sb) 467 { 468 struct msdos_sb_info *sbi = MSDOS_SB(sb); 469 470 if (sbi->nls_disk) { 471 unload_nls(sbi->nls_disk); 472 sbi->nls_disk = NULL; 473 sbi->options.codepage = fat_default_codepage; 474 } 475 if (sbi->nls_io) { 476 unload_nls(sbi->nls_io); 477 sbi->nls_io = NULL; 478 } 479 if (sbi->options.iocharset != fat_default_iocharset) { 480 kfree(sbi->options.iocharset); 481 sbi->options.iocharset = fat_default_iocharset; 482 } 483 484 sb->s_fs_info = NULL; 485 kfree(sbi); 486 } 487 488 static struct kmem_cache *fat_inode_cachep; 489 490 static struct inode *fat_alloc_inode(struct super_block *sb) 491 { 492 struct msdos_inode_info *ei; 493 ei = kmem_cache_alloc(fat_inode_cachep, GFP_KERNEL); 494 if (!ei) 495 return NULL; 496 return &ei->vfs_inode; 497 } 498 499 static void fat_destroy_inode(struct inode *inode) 500 { 501 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode)); 502 } 503 504 static void init_once(struct kmem_cache *cachep, void *foo) 505 { 506 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo; 507 508 spin_lock_init(&ei->cache_lru_lock); 509 ei->nr_caches = 0; 510 ei->cache_valid_id = FAT_CACHE_VALID + 1; 511 INIT_LIST_HEAD(&ei->cache_lru); 512 INIT_HLIST_NODE(&ei->i_fat_hash); 513 inode_init_once(&ei->vfs_inode); 514 } 515 516 static int __init fat_init_inodecache(void) 517 { 518 fat_inode_cachep = kmem_cache_create("fat_inode_cache", 519 sizeof(struct msdos_inode_info), 520 0, (SLAB_RECLAIM_ACCOUNT| 521 SLAB_MEM_SPREAD), 522 init_once); 523 if (fat_inode_cachep == NULL) 524 return -ENOMEM; 525 return 0; 526 } 527 528 static void __exit fat_destroy_inodecache(void) 529 { 530 kmem_cache_destroy(fat_inode_cachep); 531 } 532 533 static int fat_remount(struct super_block *sb, int *flags, char *data) 534 { 535 struct msdos_sb_info *sbi = MSDOS_SB(sb); 536 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME); 537 return 0; 538 } 539 540 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf) 541 { 542 struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb); 543 544 /* If the count of free cluster is still unknown, counts it here. */ 545 if (sbi->free_clusters == -1) { 546 int err = fat_count_free_clusters(dentry->d_sb); 547 if (err) 548 return err; 549 } 550 551 buf->f_type = dentry->d_sb->s_magic; 552 buf->f_bsize = sbi->cluster_size; 553 buf->f_blocks = sbi->max_cluster - FAT_START_ENT; 554 buf->f_bfree = sbi->free_clusters; 555 buf->f_bavail = sbi->free_clusters; 556 buf->f_namelen = sbi->options.isvfat ? 260 : 12; 557 558 return 0; 559 } 560 561 static int fat_write_inode(struct inode *inode, int wait) 562 { 563 struct super_block *sb = inode->i_sb; 564 struct msdos_sb_info *sbi = MSDOS_SB(sb); 565 struct buffer_head *bh; 566 struct msdos_dir_entry *raw_entry; 567 loff_t i_pos; 568 int err = 0; 569 570 retry: 571 i_pos = MSDOS_I(inode)->i_pos; 572 if (inode->i_ino == MSDOS_ROOT_INO || !i_pos) 573 return 0; 574 575 lock_kernel(); 576 bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits); 577 if (!bh) { 578 printk(KERN_ERR "FAT: unable to read inode block " 579 "for updating (i_pos %lld)\n", i_pos); 580 err = -EIO; 581 goto out; 582 } 583 spin_lock(&sbi->inode_hash_lock); 584 if (i_pos != MSDOS_I(inode)->i_pos) { 585 spin_unlock(&sbi->inode_hash_lock); 586 brelse(bh); 587 unlock_kernel(); 588 goto retry; 589 } 590 591 raw_entry = &((struct msdos_dir_entry *) (bh->b_data)) 592 [i_pos & (sbi->dir_per_block - 1)]; 593 if (S_ISDIR(inode->i_mode)) 594 raw_entry->size = 0; 595 else 596 raw_entry->size = cpu_to_le32(inode->i_size); 597 raw_entry->attr = fat_attr(inode); 598 raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart); 599 raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16); 600 fat_date_unix2dos(inode->i_mtime.tv_sec, &raw_entry->time, &raw_entry->date); 601 if (sbi->options.isvfat) { 602 __le16 atime; 603 fat_date_unix2dos(inode->i_ctime.tv_sec,&raw_entry->ctime,&raw_entry->cdate); 604 fat_date_unix2dos(inode->i_atime.tv_sec,&atime,&raw_entry->adate); 605 raw_entry->ctime_cs = (inode->i_ctime.tv_sec & 1) * 100 + 606 inode->i_ctime.tv_nsec / 10000000; 607 } 608 spin_unlock(&sbi->inode_hash_lock); 609 mark_buffer_dirty(bh); 610 if (wait) 611 err = sync_dirty_buffer(bh); 612 brelse(bh); 613 out: 614 unlock_kernel(); 615 return err; 616 } 617 618 int fat_sync_inode(struct inode *inode) 619 { 620 return fat_write_inode(inode, 1); 621 } 622 623 EXPORT_SYMBOL_GPL(fat_sync_inode); 624 625 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt); 626 static const struct super_operations fat_sops = { 627 .alloc_inode = fat_alloc_inode, 628 .destroy_inode = fat_destroy_inode, 629 .write_inode = fat_write_inode, 630 .delete_inode = fat_delete_inode, 631 .put_super = fat_put_super, 632 .write_super = fat_write_super, 633 .statfs = fat_statfs, 634 .clear_inode = fat_clear_inode, 635 .remount_fs = fat_remount, 636 637 .show_options = fat_show_options, 638 }; 639 640 /* 641 * a FAT file handle with fhtype 3 is 642 * 0/ i_ino - for fast, reliable lookup if still in the cache 643 * 1/ i_generation - to see if i_ino is still valid 644 * bit 0 == 0 iff directory 645 * 2/ i_pos(8-39) - if ino has changed, but still in cache 646 * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos 647 * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc 648 * 649 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum 650 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits 651 * of i_logstart is used to store the directory entry offset. 652 */ 653 654 static struct dentry *fat_fh_to_dentry(struct super_block *sb, 655 struct fid *fid, int fh_len, int fh_type) 656 { 657 struct inode *inode = NULL; 658 struct dentry *result; 659 u32 *fh = fid->raw; 660 661 if (fh_len < 5 || fh_type != 3) 662 return NULL; 663 664 inode = ilookup(sb, fh[0]); 665 if (!inode || inode->i_generation != fh[1]) { 666 if (inode) 667 iput(inode); 668 inode = NULL; 669 } 670 if (!inode) { 671 loff_t i_pos; 672 int i_logstart = fh[3] & 0x0fffffff; 673 674 i_pos = (loff_t)fh[2] << 8; 675 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28); 676 677 /* try 2 - see if i_pos is in F-d-c 678 * require i_logstart to be the same 679 * Will fail if you truncate and then re-write 680 */ 681 682 inode = fat_iget(sb, i_pos); 683 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) { 684 iput(inode); 685 inode = NULL; 686 } 687 } 688 if (!inode) { 689 /* For now, do nothing 690 * What we could do is: 691 * follow the file starting at fh[4], and record 692 * the ".." entry, and the name of the fh[2] entry. 693 * The follow the ".." file finding the next step up. 694 * This way we build a path to the root of 695 * the tree. If this works, we lookup the path and so 696 * get this inode into the cache. 697 * Finally try the fat_iget lookup again 698 * If that fails, then weare totally out of luck 699 * But all that is for another day 700 */ 701 } 702 if (!inode) 703 return ERR_PTR(-ESTALE); 704 705 706 /* now to find a dentry. 707 * If possible, get a well-connected one 708 */ 709 result = d_alloc_anon(inode); 710 if (result == NULL) { 711 iput(inode); 712 return ERR_PTR(-ENOMEM); 713 } 714 result->d_op = sb->s_root->d_op; 715 return result; 716 } 717 718 static int 719 fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable) 720 { 721 int len = *lenp; 722 struct inode *inode = de->d_inode; 723 u32 ipos_h, ipos_m, ipos_l; 724 725 if (len < 5) 726 return 255; /* no room */ 727 728 ipos_h = MSDOS_I(inode)->i_pos >> 8; 729 ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24; 730 ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28; 731 *lenp = 5; 732 fh[0] = inode->i_ino; 733 fh[1] = inode->i_generation; 734 fh[2] = ipos_h; 735 fh[3] = ipos_m | MSDOS_I(inode)->i_logstart; 736 spin_lock(&de->d_lock); 737 fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart; 738 spin_unlock(&de->d_lock); 739 return 3; 740 } 741 742 static struct dentry *fat_get_parent(struct dentry *child) 743 { 744 struct buffer_head *bh; 745 struct msdos_dir_entry *de; 746 loff_t i_pos; 747 struct dentry *parent; 748 struct inode *inode; 749 int err; 750 751 lock_kernel(); 752 753 err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos); 754 if (err) { 755 parent = ERR_PTR(err); 756 goto out; 757 } 758 inode = fat_build_inode(child->d_sb, de, i_pos); 759 brelse(bh); 760 if (IS_ERR(inode)) { 761 parent = ERR_CAST(inode); 762 goto out; 763 } 764 parent = d_alloc_anon(inode); 765 if (!parent) { 766 iput(inode); 767 parent = ERR_PTR(-ENOMEM); 768 } 769 out: 770 unlock_kernel(); 771 772 return parent; 773 } 774 775 static const struct export_operations fat_export_ops = { 776 .encode_fh = fat_encode_fh, 777 .fh_to_dentry = fat_fh_to_dentry, 778 .get_parent = fat_get_parent, 779 }; 780 781 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt) 782 { 783 struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb); 784 struct fat_mount_options *opts = &sbi->options; 785 int isvfat = opts->isvfat; 786 787 if (opts->fs_uid != 0) 788 seq_printf(m, ",uid=%u", opts->fs_uid); 789 if (opts->fs_gid != 0) 790 seq_printf(m, ",gid=%u", opts->fs_gid); 791 seq_printf(m, ",fmask=%04o", opts->fs_fmask); 792 seq_printf(m, ",dmask=%04o", opts->fs_dmask); 793 if (sbi->nls_disk) 794 seq_printf(m, ",codepage=%s", sbi->nls_disk->charset); 795 if (isvfat) { 796 if (sbi->nls_io) 797 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset); 798 799 switch (opts->shortname) { 800 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95: 801 seq_puts(m, ",shortname=win95"); 802 break; 803 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT: 804 seq_puts(m, ",shortname=winnt"); 805 break; 806 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95: 807 seq_puts(m, ",shortname=mixed"); 808 break; 809 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95: 810 /* seq_puts(m, ",shortname=lower"); */ 811 break; 812 default: 813 seq_puts(m, ",shortname=unknown"); 814 break; 815 } 816 } 817 if (opts->name_check != 'n') 818 seq_printf(m, ",check=%c", opts->name_check); 819 if (opts->usefree) 820 seq_puts(m, ",usefree"); 821 if (opts->quiet) 822 seq_puts(m, ",quiet"); 823 if (opts->showexec) 824 seq_puts(m, ",showexec"); 825 if (opts->sys_immutable) 826 seq_puts(m, ",sys_immutable"); 827 if (!isvfat) { 828 if (opts->dotsOK) 829 seq_puts(m, ",dotsOK=yes"); 830 if (opts->nocase) 831 seq_puts(m, ",nocase"); 832 } else { 833 if (opts->utf8) 834 seq_puts(m, ",utf8"); 835 if (opts->unicode_xlate) 836 seq_puts(m, ",uni_xlate"); 837 if (!opts->numtail) 838 seq_puts(m, ",nonumtail"); 839 } 840 if (sbi->options.flush) 841 seq_puts(m, ",flush"); 842 843 return 0; 844 } 845 846 enum { 847 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid, 848 Opt_umask, Opt_dmask, Opt_fmask, Opt_codepage, Opt_usefree, Opt_nocase, 849 Opt_quiet, Opt_showexec, Opt_debug, Opt_immutable, 850 Opt_dots, Opt_nodots, 851 Opt_charset, Opt_shortname_lower, Opt_shortname_win95, 852 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes, 853 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes, 854 Opt_obsolate, Opt_flush, Opt_err, 855 }; 856 857 static match_table_t fat_tokens = { 858 {Opt_check_r, "check=relaxed"}, 859 {Opt_check_s, "check=strict"}, 860 {Opt_check_n, "check=normal"}, 861 {Opt_check_r, "check=r"}, 862 {Opt_check_s, "check=s"}, 863 {Opt_check_n, "check=n"}, 864 {Opt_uid, "uid=%u"}, 865 {Opt_gid, "gid=%u"}, 866 {Opt_umask, "umask=%o"}, 867 {Opt_dmask, "dmask=%o"}, 868 {Opt_fmask, "fmask=%o"}, 869 {Opt_codepage, "codepage=%u"}, 870 {Opt_usefree, "usefree"}, 871 {Opt_nocase, "nocase"}, 872 {Opt_quiet, "quiet"}, 873 {Opt_showexec, "showexec"}, 874 {Opt_debug, "debug"}, 875 {Opt_immutable, "sys_immutable"}, 876 {Opt_obsolate, "conv=binary"}, 877 {Opt_obsolate, "conv=text"}, 878 {Opt_obsolate, "conv=auto"}, 879 {Opt_obsolate, "conv=b"}, 880 {Opt_obsolate, "conv=t"}, 881 {Opt_obsolate, "conv=a"}, 882 {Opt_obsolate, "fat=%u"}, 883 {Opt_obsolate, "blocksize=%u"}, 884 {Opt_obsolate, "cvf_format=%20s"}, 885 {Opt_obsolate, "cvf_options=%100s"}, 886 {Opt_obsolate, "posix"}, 887 {Opt_flush, "flush"}, 888 {Opt_err, NULL}, 889 }; 890 static match_table_t msdos_tokens = { 891 {Opt_nodots, "nodots"}, 892 {Opt_nodots, "dotsOK=no"}, 893 {Opt_dots, "dots"}, 894 {Opt_dots, "dotsOK=yes"}, 895 {Opt_err, NULL} 896 }; 897 static match_table_t vfat_tokens = { 898 {Opt_charset, "iocharset=%s"}, 899 {Opt_shortname_lower, "shortname=lower"}, 900 {Opt_shortname_win95, "shortname=win95"}, 901 {Opt_shortname_winnt, "shortname=winnt"}, 902 {Opt_shortname_mixed, "shortname=mixed"}, 903 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */ 904 {Opt_utf8_no, "utf8=no"}, 905 {Opt_utf8_no, "utf8=false"}, 906 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */ 907 {Opt_utf8_yes, "utf8=yes"}, 908 {Opt_utf8_yes, "utf8=true"}, 909 {Opt_utf8_yes, "utf8"}, 910 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */ 911 {Opt_uni_xl_no, "uni_xlate=no"}, 912 {Opt_uni_xl_no, "uni_xlate=false"}, 913 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */ 914 {Opt_uni_xl_yes, "uni_xlate=yes"}, 915 {Opt_uni_xl_yes, "uni_xlate=true"}, 916 {Opt_uni_xl_yes, "uni_xlate"}, 917 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */ 918 {Opt_nonumtail_no, "nonumtail=no"}, 919 {Opt_nonumtail_no, "nonumtail=false"}, 920 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */ 921 {Opt_nonumtail_yes, "nonumtail=yes"}, 922 {Opt_nonumtail_yes, "nonumtail=true"}, 923 {Opt_nonumtail_yes, "nonumtail"}, 924 {Opt_err, NULL} 925 }; 926 927 static int parse_options(char *options, int is_vfat, int silent, int *debug, 928 struct fat_mount_options *opts) 929 { 930 char *p; 931 substring_t args[MAX_OPT_ARGS]; 932 int option; 933 char *iocharset; 934 935 opts->isvfat = is_vfat; 936 937 opts->fs_uid = current->uid; 938 opts->fs_gid = current->gid; 939 opts->fs_fmask = opts->fs_dmask = current->fs->umask; 940 opts->codepage = fat_default_codepage; 941 opts->iocharset = fat_default_iocharset; 942 if (is_vfat) 943 opts->shortname = VFAT_SFN_DISPLAY_LOWER|VFAT_SFN_CREATE_WIN95; 944 else 945 opts->shortname = 0; 946 opts->name_check = 'n'; 947 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0; 948 opts->utf8 = opts->unicode_xlate = 0; 949 opts->numtail = 1; 950 opts->usefree = opts->nocase = 0; 951 *debug = 0; 952 953 if (!options) 954 return 0; 955 956 while ((p = strsep(&options, ",")) != NULL) { 957 int token; 958 if (!*p) 959 continue; 960 961 token = match_token(p, fat_tokens, args); 962 if (token == Opt_err) { 963 if (is_vfat) 964 token = match_token(p, vfat_tokens, args); 965 else 966 token = match_token(p, msdos_tokens, args); 967 } 968 switch (token) { 969 case Opt_check_s: 970 opts->name_check = 's'; 971 break; 972 case Opt_check_r: 973 opts->name_check = 'r'; 974 break; 975 case Opt_check_n: 976 opts->name_check = 'n'; 977 break; 978 case Opt_usefree: 979 opts->usefree = 1; 980 break; 981 case Opt_nocase: 982 if (!is_vfat) 983 opts->nocase = 1; 984 else { 985 /* for backward compatibility */ 986 opts->shortname = VFAT_SFN_DISPLAY_WIN95 987 | VFAT_SFN_CREATE_WIN95; 988 } 989 break; 990 case Opt_quiet: 991 opts->quiet = 1; 992 break; 993 case Opt_showexec: 994 opts->showexec = 1; 995 break; 996 case Opt_debug: 997 *debug = 1; 998 break; 999 case Opt_immutable: 1000 opts->sys_immutable = 1; 1001 break; 1002 case Opt_uid: 1003 if (match_int(&args[0], &option)) 1004 return 0; 1005 opts->fs_uid = option; 1006 break; 1007 case Opt_gid: 1008 if (match_int(&args[0], &option)) 1009 return 0; 1010 opts->fs_gid = option; 1011 break; 1012 case Opt_umask: 1013 if (match_octal(&args[0], &option)) 1014 return 0; 1015 opts->fs_fmask = opts->fs_dmask = option; 1016 break; 1017 case Opt_dmask: 1018 if (match_octal(&args[0], &option)) 1019 return 0; 1020 opts->fs_dmask = option; 1021 break; 1022 case Opt_fmask: 1023 if (match_octal(&args[0], &option)) 1024 return 0; 1025 opts->fs_fmask = option; 1026 break; 1027 case Opt_codepage: 1028 if (match_int(&args[0], &option)) 1029 return 0; 1030 opts->codepage = option; 1031 break; 1032 case Opt_flush: 1033 opts->flush = 1; 1034 break; 1035 1036 /* msdos specific */ 1037 case Opt_dots: 1038 opts->dotsOK = 1; 1039 break; 1040 case Opt_nodots: 1041 opts->dotsOK = 0; 1042 break; 1043 1044 /* vfat specific */ 1045 case Opt_charset: 1046 if (opts->iocharset != fat_default_iocharset) 1047 kfree(opts->iocharset); 1048 iocharset = match_strdup(&args[0]); 1049 if (!iocharset) 1050 return -ENOMEM; 1051 opts->iocharset = iocharset; 1052 break; 1053 case Opt_shortname_lower: 1054 opts->shortname = VFAT_SFN_DISPLAY_LOWER 1055 | VFAT_SFN_CREATE_WIN95; 1056 break; 1057 case Opt_shortname_win95: 1058 opts->shortname = VFAT_SFN_DISPLAY_WIN95 1059 | VFAT_SFN_CREATE_WIN95; 1060 break; 1061 case Opt_shortname_winnt: 1062 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1063 | VFAT_SFN_CREATE_WINNT; 1064 break; 1065 case Opt_shortname_mixed: 1066 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1067 | VFAT_SFN_CREATE_WIN95; 1068 break; 1069 case Opt_utf8_no: /* 0 or no or false */ 1070 opts->utf8 = 0; 1071 break; 1072 case Opt_utf8_yes: /* empty or 1 or yes or true */ 1073 opts->utf8 = 1; 1074 break; 1075 case Opt_uni_xl_no: /* 0 or no or false */ 1076 opts->unicode_xlate = 0; 1077 break; 1078 case Opt_uni_xl_yes: /* empty or 1 or yes or true */ 1079 opts->unicode_xlate = 1; 1080 break; 1081 case Opt_nonumtail_no: /* 0 or no or false */ 1082 opts->numtail = 1; /* negated option */ 1083 break; 1084 case Opt_nonumtail_yes: /* empty or 1 or yes or true */ 1085 opts->numtail = 0; /* negated option */ 1086 break; 1087 1088 /* obsolete mount options */ 1089 case Opt_obsolate: 1090 printk(KERN_INFO "FAT: \"%s\" option is obsolete, " 1091 "not supported now\n", p); 1092 break; 1093 /* unknown option */ 1094 default: 1095 if (!silent) { 1096 printk(KERN_ERR 1097 "FAT: Unrecognized mount option \"%s\" " 1098 "or missing value\n", p); 1099 } 1100 return -EINVAL; 1101 } 1102 } 1103 /* UTF-8 doesn't provide FAT semantics */ 1104 if (!strcmp(opts->iocharset, "utf8")) { 1105 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset" 1106 " for FAT filesystems, filesystem will be case sensitive!\n"); 1107 } 1108 1109 if (opts->unicode_xlate) 1110 opts->utf8 = 0; 1111 1112 return 0; 1113 } 1114 1115 static int fat_read_root(struct inode *inode) 1116 { 1117 struct super_block *sb = inode->i_sb; 1118 struct msdos_sb_info *sbi = MSDOS_SB(sb); 1119 int error; 1120 1121 MSDOS_I(inode)->i_pos = 0; 1122 inode->i_uid = sbi->options.fs_uid; 1123 inode->i_gid = sbi->options.fs_gid; 1124 inode->i_version++; 1125 inode->i_generation = 0; 1126 inode->i_mode = (S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR; 1127 inode->i_op = sbi->dir_ops; 1128 inode->i_fop = &fat_dir_operations; 1129 if (sbi->fat_bits == 32) { 1130 MSDOS_I(inode)->i_start = sbi->root_cluster; 1131 error = fat_calc_dir_size(inode); 1132 if (error < 0) 1133 return error; 1134 } else { 1135 MSDOS_I(inode)->i_start = 0; 1136 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry); 1137 } 1138 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 1139 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 1140 MSDOS_I(inode)->i_logstart = 0; 1141 MSDOS_I(inode)->mmu_private = inode->i_size; 1142 1143 MSDOS_I(inode)->i_attrs = ATTR_NONE; 1144 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0; 1145 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0; 1146 inode->i_nlink = fat_subdirs(inode)+2; 1147 1148 return 0; 1149 } 1150 1151 /* 1152 * Read the super block of an MS-DOS FS. 1153 */ 1154 int fat_fill_super(struct super_block *sb, void *data, int silent, 1155 const struct inode_operations *fs_dir_inode_ops, int isvfat) 1156 { 1157 struct inode *root_inode = NULL; 1158 struct buffer_head *bh; 1159 struct fat_boot_sector *b; 1160 struct msdos_sb_info *sbi; 1161 u16 logical_sector_size; 1162 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors; 1163 int debug; 1164 unsigned int media; 1165 long error; 1166 char buf[50]; 1167 1168 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL); 1169 if (!sbi) 1170 return -ENOMEM; 1171 sb->s_fs_info = sbi; 1172 1173 sb->s_flags |= MS_NODIRATIME; 1174 sb->s_magic = MSDOS_SUPER_MAGIC; 1175 sb->s_op = &fat_sops; 1176 sb->s_export_op = &fat_export_ops; 1177 sbi->dir_ops = fs_dir_inode_ops; 1178 1179 error = parse_options(data, isvfat, silent, &debug, &sbi->options); 1180 if (error) 1181 goto out_fail; 1182 1183 error = -EIO; 1184 sb_min_blocksize(sb, 512); 1185 bh = sb_bread(sb, 0); 1186 if (bh == NULL) { 1187 printk(KERN_ERR "FAT: unable to read boot sector\n"); 1188 goto out_fail; 1189 } 1190 1191 b = (struct fat_boot_sector *) bh->b_data; 1192 if (!b->reserved) { 1193 if (!silent) 1194 printk(KERN_ERR "FAT: bogus number of reserved sectors\n"); 1195 brelse(bh); 1196 goto out_invalid; 1197 } 1198 if (!b->fats) { 1199 if (!silent) 1200 printk(KERN_ERR "FAT: bogus number of FAT structure\n"); 1201 brelse(bh); 1202 goto out_invalid; 1203 } 1204 1205 /* 1206 * Earlier we checked here that b->secs_track and b->head are nonzero, 1207 * but it turns out valid FAT filesystems can have zero there. 1208 */ 1209 1210 media = b->media; 1211 if (!FAT_VALID_MEDIA(media)) { 1212 if (!silent) 1213 printk(KERN_ERR "FAT: invalid media value (0x%02x)\n", 1214 media); 1215 brelse(bh); 1216 goto out_invalid; 1217 } 1218 logical_sector_size = 1219 le16_to_cpu(get_unaligned((__le16 *)&b->sector_size)); 1220 if (!is_power_of_2(logical_sector_size) 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 (!is_power_of_2(sbi->sec_per_clus)) { 1231 if (!silent) 1232 printk(KERN_ERR "FAT: bogus sectors per cluster %u\n", 1233 sbi->sec_per_clus); 1234 brelse(bh); 1235 goto out_invalid; 1236 } 1237 1238 if (logical_sector_size < sb->s_blocksize) { 1239 printk(KERN_ERR "FAT: logical sector size too small for device" 1240 " (logical sector size = %u)\n", logical_sector_size); 1241 brelse(bh); 1242 goto out_fail; 1243 } 1244 if (logical_sector_size > sb->s_blocksize) { 1245 brelse(bh); 1246 1247 if (!sb_set_blocksize(sb, logical_sector_size)) { 1248 printk(KERN_ERR "FAT: unable to set blocksize %u\n", 1249 logical_sector_size); 1250 goto out_fail; 1251 } 1252 bh = sb_bread(sb, 0); 1253 if (bh == NULL) { 1254 printk(KERN_ERR "FAT: unable to read boot sector" 1255 " (logical sector size = %lu)\n", 1256 sb->s_blocksize); 1257 goto out_fail; 1258 } 1259 b = (struct fat_boot_sector *) bh->b_data; 1260 } 1261 1262 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus; 1263 sbi->cluster_bits = ffs(sbi->cluster_size) - 1; 1264 sbi->fats = b->fats; 1265 sbi->fat_bits = 0; /* Don't know yet */ 1266 sbi->fat_start = le16_to_cpu(b->reserved); 1267 sbi->fat_length = le16_to_cpu(b->fat_length); 1268 sbi->root_cluster = 0; 1269 sbi->free_clusters = -1; /* Don't know yet */ 1270 sbi->prev_free = FAT_START_ENT; 1271 1272 if (!sbi->fat_length && b->fat32_length) { 1273 struct fat_boot_fsinfo *fsinfo; 1274 struct buffer_head *fsinfo_bh; 1275 1276 /* Must be FAT32 */ 1277 sbi->fat_bits = 32; 1278 sbi->fat_length = le32_to_cpu(b->fat32_length); 1279 sbi->root_cluster = le32_to_cpu(b->root_cluster); 1280 1281 sb->s_maxbytes = 0xffffffff; 1282 1283 /* MC - if info_sector is 0, don't multiply by 0 */ 1284 sbi->fsinfo_sector = le16_to_cpu(b->info_sector); 1285 if (sbi->fsinfo_sector == 0) 1286 sbi->fsinfo_sector = 1; 1287 1288 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector); 1289 if (fsinfo_bh == NULL) { 1290 printk(KERN_ERR "FAT: bread failed, FSINFO block" 1291 " (sector = %lu)\n", sbi->fsinfo_sector); 1292 brelse(bh); 1293 goto out_fail; 1294 } 1295 1296 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data; 1297 if (!IS_FSINFO(fsinfo)) { 1298 printk(KERN_WARNING "FAT: Invalid FSINFO signature: " 1299 "0x%08x, 0x%08x (sector = %lu)\n", 1300 le32_to_cpu(fsinfo->signature1), 1301 le32_to_cpu(fsinfo->signature2), 1302 sbi->fsinfo_sector); 1303 } else { 1304 if (sbi->options.usefree) 1305 sbi->free_clusters = 1306 le32_to_cpu(fsinfo->free_clusters); 1307 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster); 1308 } 1309 1310 brelse(fsinfo_bh); 1311 } 1312 1313 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry); 1314 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1; 1315 1316 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length; 1317 sbi->dir_entries = 1318 le16_to_cpu(get_unaligned((__le16 *)&b->dir_entries)); 1319 if (sbi->dir_entries & (sbi->dir_per_block - 1)) { 1320 if (!silent) 1321 printk(KERN_ERR "FAT: bogus directroy-entries per block" 1322 " (%u)\n", sbi->dir_entries); 1323 brelse(bh); 1324 goto out_invalid; 1325 } 1326 1327 rootdir_sectors = sbi->dir_entries 1328 * sizeof(struct msdos_dir_entry) / sb->s_blocksize; 1329 sbi->data_start = sbi->dir_start + rootdir_sectors; 1330 total_sectors = le16_to_cpu(get_unaligned((__le16 *)&b->sectors)); 1331 if (total_sectors == 0) 1332 total_sectors = le32_to_cpu(b->total_sect); 1333 1334 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus; 1335 1336 if (sbi->fat_bits != 32) 1337 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12; 1338 1339 /* check that FAT table does not overflow */ 1340 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits; 1341 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT); 1342 if (total_clusters > MAX_FAT(sb)) { 1343 if (!silent) 1344 printk(KERN_ERR "FAT: count of clusters too big (%u)\n", 1345 total_clusters); 1346 brelse(bh); 1347 goto out_invalid; 1348 } 1349 1350 sbi->max_cluster = total_clusters + FAT_START_ENT; 1351 /* check the free_clusters, it's not necessarily correct */ 1352 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters) 1353 sbi->free_clusters = -1; 1354 /* check the prev_free, it's not necessarily correct */ 1355 sbi->prev_free %= sbi->max_cluster; 1356 if (sbi->prev_free < FAT_START_ENT) 1357 sbi->prev_free = FAT_START_ENT; 1358 1359 brelse(bh); 1360 1361 /* set up enough so that it can read an inode */ 1362 fat_hash_init(sb); 1363 fat_ent_access_init(sb); 1364 1365 /* 1366 * The low byte of FAT's first entry must have same value with 1367 * media-field. But in real world, too many devices is 1368 * writing wrong value. So, removed that validity check. 1369 * 1370 * if (FAT_FIRST_ENT(sb, media) != first) 1371 */ 1372 1373 error = -EINVAL; 1374 sprintf(buf, "cp%d", sbi->options.codepage); 1375 sbi->nls_disk = load_nls(buf); 1376 if (!sbi->nls_disk) { 1377 printk(KERN_ERR "FAT: codepage %s not found\n", buf); 1378 goto out_fail; 1379 } 1380 1381 /* FIXME: utf8 is using iocharset for upper/lower conversion */ 1382 if (sbi->options.isvfat) { 1383 sbi->nls_io = load_nls(sbi->options.iocharset); 1384 if (!sbi->nls_io) { 1385 printk(KERN_ERR "FAT: IO charset %s not found\n", 1386 sbi->options.iocharset); 1387 goto out_fail; 1388 } 1389 } 1390 1391 error = -ENOMEM; 1392 root_inode = new_inode(sb); 1393 if (!root_inode) 1394 goto out_fail; 1395 root_inode->i_ino = MSDOS_ROOT_INO; 1396 root_inode->i_version = 1; 1397 error = fat_read_root(root_inode); 1398 if (error < 0) 1399 goto out_fail; 1400 error = -ENOMEM; 1401 insert_inode_hash(root_inode); 1402 sb->s_root = d_alloc_root(root_inode); 1403 if (!sb->s_root) { 1404 printk(KERN_ERR "FAT: get root inode failed\n"); 1405 goto out_fail; 1406 } 1407 1408 return 0; 1409 1410 out_invalid: 1411 error = -EINVAL; 1412 if (!silent) 1413 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem" 1414 " on dev %s.\n", sb->s_id); 1415 1416 out_fail: 1417 if (root_inode) 1418 iput(root_inode); 1419 if (sbi->nls_io) 1420 unload_nls(sbi->nls_io); 1421 if (sbi->nls_disk) 1422 unload_nls(sbi->nls_disk); 1423 if (sbi->options.iocharset != fat_default_iocharset) 1424 kfree(sbi->options.iocharset); 1425 sb->s_fs_info = NULL; 1426 kfree(sbi); 1427 return error; 1428 } 1429 1430 EXPORT_SYMBOL_GPL(fat_fill_super); 1431 1432 /* 1433 * helper function for fat_flush_inodes. This writes both the inode 1434 * and the file data blocks, waiting for in flight data blocks before 1435 * the start of the call. It does not wait for any io started 1436 * during the call 1437 */ 1438 static int writeback_inode(struct inode *inode) 1439 { 1440 1441 int ret; 1442 struct address_space *mapping = inode->i_mapping; 1443 struct writeback_control wbc = { 1444 .sync_mode = WB_SYNC_NONE, 1445 .nr_to_write = 0, 1446 }; 1447 /* if we used WB_SYNC_ALL, sync_inode waits for the io for the 1448 * inode to finish. So WB_SYNC_NONE is sent down to sync_inode 1449 * and filemap_fdatawrite is used for the data blocks 1450 */ 1451 ret = sync_inode(inode, &wbc); 1452 if (!ret) 1453 ret = filemap_fdatawrite(mapping); 1454 return ret; 1455 } 1456 1457 /* 1458 * write data and metadata corresponding to i1 and i2. The io is 1459 * started but we do not wait for any of it to finish. 1460 * 1461 * filemap_flush is used for the block device, so if there is a dirty 1462 * page for a block already in flight, we will not wait and start the 1463 * io over again 1464 */ 1465 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2) 1466 { 1467 int ret = 0; 1468 if (!MSDOS_SB(sb)->options.flush) 1469 return 0; 1470 if (i1) 1471 ret = writeback_inode(i1); 1472 if (!ret && i2) 1473 ret = writeback_inode(i2); 1474 if (!ret) { 1475 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping; 1476 ret = filemap_flush(mapping); 1477 } 1478 return ret; 1479 } 1480 EXPORT_SYMBOL_GPL(fat_flush_inodes); 1481 1482 static int __init init_fat_fs(void) 1483 { 1484 int err; 1485 1486 err = fat_cache_init(); 1487 if (err) 1488 return err; 1489 1490 err = fat_init_inodecache(); 1491 if (err) 1492 goto failed; 1493 1494 return 0; 1495 1496 failed: 1497 fat_cache_destroy(); 1498 return err; 1499 } 1500 1501 static void __exit exit_fat_fs(void) 1502 { 1503 fat_cache_destroy(); 1504 fat_destroy_inodecache(); 1505 } 1506 1507 module_init(init_fat_fs) 1508 module_exit(exit_fat_fs) 1509 1510 MODULE_LICENSE("GPL"); 1511