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 .read_inode = make_bad_inode, 638 639 .show_options = fat_show_options, 640 }; 641 642 /* 643 * a FAT file handle with fhtype 3 is 644 * 0/ i_ino - for fast, reliable lookup if still in the cache 645 * 1/ i_generation - to see if i_ino is still valid 646 * bit 0 == 0 iff directory 647 * 2/ i_pos(8-39) - if ino has changed, but still in cache 648 * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos 649 * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc 650 * 651 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum 652 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits 653 * of i_logstart is used to store the directory entry offset. 654 */ 655 656 static struct dentry * 657 fat_decode_fh(struct super_block *sb, __u32 *fh, int len, int fhtype, 658 int (*acceptable)(void *context, struct dentry *de), 659 void *context) 660 { 661 if (fhtype != 3) 662 return ERR_PTR(-ESTALE); 663 if (len < 5) 664 return ERR_PTR(-ESTALE); 665 666 return sb->s_export_op->find_exported_dentry(sb, fh, NULL, acceptable, context); 667 } 668 669 static struct dentry *fat_get_dentry(struct super_block *sb, void *inump) 670 { 671 struct inode *inode = NULL; 672 struct dentry *result; 673 __u32 *fh = inump; 674 675 inode = iget(sb, fh[0]); 676 if (!inode || is_bad_inode(inode) || inode->i_generation != fh[1]) { 677 if (inode) 678 iput(inode); 679 inode = NULL; 680 } 681 if (!inode) { 682 loff_t i_pos; 683 int i_logstart = fh[3] & 0x0fffffff; 684 685 i_pos = (loff_t)fh[2] << 8; 686 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28); 687 688 /* try 2 - see if i_pos is in F-d-c 689 * require i_logstart to be the same 690 * Will fail if you truncate and then re-write 691 */ 692 693 inode = fat_iget(sb, i_pos); 694 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) { 695 iput(inode); 696 inode = NULL; 697 } 698 } 699 if (!inode) { 700 /* For now, do nothing 701 * What we could do is: 702 * follow the file starting at fh[4], and record 703 * the ".." entry, and the name of the fh[2] entry. 704 * The follow the ".." file finding the next step up. 705 * This way we build a path to the root of 706 * the tree. If this works, we lookup the path and so 707 * get this inode into the cache. 708 * Finally try the fat_iget lookup again 709 * If that fails, then weare totally out of luck 710 * But all that is for another day 711 */ 712 } 713 if (!inode) 714 return ERR_PTR(-ESTALE); 715 716 717 /* now to find a dentry. 718 * If possible, get a well-connected one 719 */ 720 result = d_alloc_anon(inode); 721 if (result == NULL) { 722 iput(inode); 723 return ERR_PTR(-ENOMEM); 724 } 725 result->d_op = sb->s_root->d_op; 726 return result; 727 } 728 729 static int 730 fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable) 731 { 732 int len = *lenp; 733 struct inode *inode = de->d_inode; 734 u32 ipos_h, ipos_m, ipos_l; 735 736 if (len < 5) 737 return 255; /* no room */ 738 739 ipos_h = MSDOS_I(inode)->i_pos >> 8; 740 ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24; 741 ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28; 742 *lenp = 5; 743 fh[0] = inode->i_ino; 744 fh[1] = inode->i_generation; 745 fh[2] = ipos_h; 746 fh[3] = ipos_m | MSDOS_I(inode)->i_logstart; 747 spin_lock(&de->d_lock); 748 fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart; 749 spin_unlock(&de->d_lock); 750 return 3; 751 } 752 753 static struct dentry *fat_get_parent(struct dentry *child) 754 { 755 struct buffer_head *bh; 756 struct msdos_dir_entry *de; 757 loff_t i_pos; 758 struct dentry *parent; 759 struct inode *inode; 760 int err; 761 762 lock_kernel(); 763 764 err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos); 765 if (err) { 766 parent = ERR_PTR(err); 767 goto out; 768 } 769 inode = fat_build_inode(child->d_sb, de, i_pos); 770 brelse(bh); 771 if (IS_ERR(inode)) { 772 parent = ERR_PTR(PTR_ERR(inode)); 773 goto out; 774 } 775 parent = d_alloc_anon(inode); 776 if (!parent) { 777 iput(inode); 778 parent = ERR_PTR(-ENOMEM); 779 } 780 out: 781 unlock_kernel(); 782 783 return parent; 784 } 785 786 static struct export_operations fat_export_ops = { 787 .decode_fh = fat_decode_fh, 788 .encode_fh = fat_encode_fh, 789 .get_dentry = fat_get_dentry, 790 .get_parent = fat_get_parent, 791 }; 792 793 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt) 794 { 795 struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb); 796 struct fat_mount_options *opts = &sbi->options; 797 int isvfat = opts->isvfat; 798 799 if (opts->fs_uid != 0) 800 seq_printf(m, ",uid=%u", opts->fs_uid); 801 if (opts->fs_gid != 0) 802 seq_printf(m, ",gid=%u", opts->fs_gid); 803 seq_printf(m, ",fmask=%04o", opts->fs_fmask); 804 seq_printf(m, ",dmask=%04o", opts->fs_dmask); 805 if (sbi->nls_disk) 806 seq_printf(m, ",codepage=%s", sbi->nls_disk->charset); 807 if (isvfat) { 808 if (sbi->nls_io) 809 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset); 810 811 switch (opts->shortname) { 812 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95: 813 seq_puts(m, ",shortname=win95"); 814 break; 815 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT: 816 seq_puts(m, ",shortname=winnt"); 817 break; 818 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95: 819 seq_puts(m, ",shortname=mixed"); 820 break; 821 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95: 822 /* seq_puts(m, ",shortname=lower"); */ 823 break; 824 default: 825 seq_puts(m, ",shortname=unknown"); 826 break; 827 } 828 } 829 if (opts->name_check != 'n') 830 seq_printf(m, ",check=%c", opts->name_check); 831 if (opts->usefree) 832 seq_puts(m, ",usefree"); 833 if (opts->quiet) 834 seq_puts(m, ",quiet"); 835 if (opts->showexec) 836 seq_puts(m, ",showexec"); 837 if (opts->sys_immutable) 838 seq_puts(m, ",sys_immutable"); 839 if (!isvfat) { 840 if (opts->dotsOK) 841 seq_puts(m, ",dotsOK=yes"); 842 if (opts->nocase) 843 seq_puts(m, ",nocase"); 844 } else { 845 if (opts->utf8) 846 seq_puts(m, ",utf8"); 847 if (opts->unicode_xlate) 848 seq_puts(m, ",uni_xlate"); 849 if (!opts->numtail) 850 seq_puts(m, ",nonumtail"); 851 } 852 853 return 0; 854 } 855 856 enum { 857 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid, 858 Opt_umask, Opt_dmask, Opt_fmask, Opt_codepage, Opt_usefree, Opt_nocase, 859 Opt_quiet, Opt_showexec, Opt_debug, Opt_immutable, 860 Opt_dots, Opt_nodots, 861 Opt_charset, Opt_shortname_lower, Opt_shortname_win95, 862 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes, 863 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes, 864 Opt_obsolate, Opt_flush, Opt_err, 865 }; 866 867 static match_table_t fat_tokens = { 868 {Opt_check_r, "check=relaxed"}, 869 {Opt_check_s, "check=strict"}, 870 {Opt_check_n, "check=normal"}, 871 {Opt_check_r, "check=r"}, 872 {Opt_check_s, "check=s"}, 873 {Opt_check_n, "check=n"}, 874 {Opt_uid, "uid=%u"}, 875 {Opt_gid, "gid=%u"}, 876 {Opt_umask, "umask=%o"}, 877 {Opt_dmask, "dmask=%o"}, 878 {Opt_fmask, "fmask=%o"}, 879 {Opt_codepage, "codepage=%u"}, 880 {Opt_usefree, "usefree"}, 881 {Opt_nocase, "nocase"}, 882 {Opt_quiet, "quiet"}, 883 {Opt_showexec, "showexec"}, 884 {Opt_debug, "debug"}, 885 {Opt_immutable, "sys_immutable"}, 886 {Opt_obsolate, "conv=binary"}, 887 {Opt_obsolate, "conv=text"}, 888 {Opt_obsolate, "conv=auto"}, 889 {Opt_obsolate, "conv=b"}, 890 {Opt_obsolate, "conv=t"}, 891 {Opt_obsolate, "conv=a"}, 892 {Opt_obsolate, "fat=%u"}, 893 {Opt_obsolate, "blocksize=%u"}, 894 {Opt_obsolate, "cvf_format=%20s"}, 895 {Opt_obsolate, "cvf_options=%100s"}, 896 {Opt_obsolate, "posix"}, 897 {Opt_flush, "flush"}, 898 {Opt_err, NULL}, 899 }; 900 static match_table_t msdos_tokens = { 901 {Opt_nodots, "nodots"}, 902 {Opt_nodots, "dotsOK=no"}, 903 {Opt_dots, "dots"}, 904 {Opt_dots, "dotsOK=yes"}, 905 {Opt_err, NULL} 906 }; 907 static match_table_t vfat_tokens = { 908 {Opt_charset, "iocharset=%s"}, 909 {Opt_shortname_lower, "shortname=lower"}, 910 {Opt_shortname_win95, "shortname=win95"}, 911 {Opt_shortname_winnt, "shortname=winnt"}, 912 {Opt_shortname_mixed, "shortname=mixed"}, 913 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */ 914 {Opt_utf8_no, "utf8=no"}, 915 {Opt_utf8_no, "utf8=false"}, 916 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */ 917 {Opt_utf8_yes, "utf8=yes"}, 918 {Opt_utf8_yes, "utf8=true"}, 919 {Opt_utf8_yes, "utf8"}, 920 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */ 921 {Opt_uni_xl_no, "uni_xlate=no"}, 922 {Opt_uni_xl_no, "uni_xlate=false"}, 923 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */ 924 {Opt_uni_xl_yes, "uni_xlate=yes"}, 925 {Opt_uni_xl_yes, "uni_xlate=true"}, 926 {Opt_uni_xl_yes, "uni_xlate"}, 927 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */ 928 {Opt_nonumtail_no, "nonumtail=no"}, 929 {Opt_nonumtail_no, "nonumtail=false"}, 930 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */ 931 {Opt_nonumtail_yes, "nonumtail=yes"}, 932 {Opt_nonumtail_yes, "nonumtail=true"}, 933 {Opt_nonumtail_yes, "nonumtail"}, 934 {Opt_err, NULL} 935 }; 936 937 static int parse_options(char *options, int is_vfat, int silent, int *debug, 938 struct fat_mount_options *opts) 939 { 940 char *p; 941 substring_t args[MAX_OPT_ARGS]; 942 int option; 943 char *iocharset; 944 945 opts->isvfat = is_vfat; 946 947 opts->fs_uid = current->uid; 948 opts->fs_gid = current->gid; 949 opts->fs_fmask = opts->fs_dmask = current->fs->umask; 950 opts->codepage = fat_default_codepage; 951 opts->iocharset = fat_default_iocharset; 952 if (is_vfat) 953 opts->shortname = VFAT_SFN_DISPLAY_LOWER|VFAT_SFN_CREATE_WIN95; 954 else 955 opts->shortname = 0; 956 opts->name_check = 'n'; 957 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0; 958 opts->utf8 = opts->unicode_xlate = 0; 959 opts->numtail = 1; 960 opts->usefree = opts->nocase = 0; 961 *debug = 0; 962 963 if (!options) 964 return 0; 965 966 while ((p = strsep(&options, ",")) != NULL) { 967 int token; 968 if (!*p) 969 continue; 970 971 token = match_token(p, fat_tokens, args); 972 if (token == Opt_err) { 973 if (is_vfat) 974 token = match_token(p, vfat_tokens, args); 975 else 976 token = match_token(p, msdos_tokens, args); 977 } 978 switch (token) { 979 case Opt_check_s: 980 opts->name_check = 's'; 981 break; 982 case Opt_check_r: 983 opts->name_check = 'r'; 984 break; 985 case Opt_check_n: 986 opts->name_check = 'n'; 987 break; 988 case Opt_usefree: 989 opts->usefree = 1; 990 break; 991 case Opt_nocase: 992 if (!is_vfat) 993 opts->nocase = 1; 994 else { 995 /* for backward compatibility */ 996 opts->shortname = VFAT_SFN_DISPLAY_WIN95 997 | VFAT_SFN_CREATE_WIN95; 998 } 999 break; 1000 case Opt_quiet: 1001 opts->quiet = 1; 1002 break; 1003 case Opt_showexec: 1004 opts->showexec = 1; 1005 break; 1006 case Opt_debug: 1007 *debug = 1; 1008 break; 1009 case Opt_immutable: 1010 opts->sys_immutable = 1; 1011 break; 1012 case Opt_uid: 1013 if (match_int(&args[0], &option)) 1014 return 0; 1015 opts->fs_uid = option; 1016 break; 1017 case Opt_gid: 1018 if (match_int(&args[0], &option)) 1019 return 0; 1020 opts->fs_gid = option; 1021 break; 1022 case Opt_umask: 1023 if (match_octal(&args[0], &option)) 1024 return 0; 1025 opts->fs_fmask = opts->fs_dmask = option; 1026 break; 1027 case Opt_dmask: 1028 if (match_octal(&args[0], &option)) 1029 return 0; 1030 opts->fs_dmask = option; 1031 break; 1032 case Opt_fmask: 1033 if (match_octal(&args[0], &option)) 1034 return 0; 1035 opts->fs_fmask = option; 1036 break; 1037 case Opt_codepage: 1038 if (match_int(&args[0], &option)) 1039 return 0; 1040 opts->codepage = option; 1041 break; 1042 case Opt_flush: 1043 opts->flush = 1; 1044 break; 1045 1046 /* msdos specific */ 1047 case Opt_dots: 1048 opts->dotsOK = 1; 1049 break; 1050 case Opt_nodots: 1051 opts->dotsOK = 0; 1052 break; 1053 1054 /* vfat specific */ 1055 case Opt_charset: 1056 if (opts->iocharset != fat_default_iocharset) 1057 kfree(opts->iocharset); 1058 iocharset = match_strdup(&args[0]); 1059 if (!iocharset) 1060 return -ENOMEM; 1061 opts->iocharset = iocharset; 1062 break; 1063 case Opt_shortname_lower: 1064 opts->shortname = VFAT_SFN_DISPLAY_LOWER 1065 | VFAT_SFN_CREATE_WIN95; 1066 break; 1067 case Opt_shortname_win95: 1068 opts->shortname = VFAT_SFN_DISPLAY_WIN95 1069 | VFAT_SFN_CREATE_WIN95; 1070 break; 1071 case Opt_shortname_winnt: 1072 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1073 | VFAT_SFN_CREATE_WINNT; 1074 break; 1075 case Opt_shortname_mixed: 1076 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1077 | VFAT_SFN_CREATE_WIN95; 1078 break; 1079 case Opt_utf8_no: /* 0 or no or false */ 1080 opts->utf8 = 0; 1081 break; 1082 case Opt_utf8_yes: /* empty or 1 or yes or true */ 1083 opts->utf8 = 1; 1084 break; 1085 case Opt_uni_xl_no: /* 0 or no or false */ 1086 opts->unicode_xlate = 0; 1087 break; 1088 case Opt_uni_xl_yes: /* empty or 1 or yes or true */ 1089 opts->unicode_xlate = 1; 1090 break; 1091 case Opt_nonumtail_no: /* 0 or no or false */ 1092 opts->numtail = 1; /* negated option */ 1093 break; 1094 case Opt_nonumtail_yes: /* empty or 1 or yes or true */ 1095 opts->numtail = 0; /* negated option */ 1096 break; 1097 1098 /* obsolete mount options */ 1099 case Opt_obsolate: 1100 printk(KERN_INFO "FAT: \"%s\" option is obsolete, " 1101 "not supported now\n", p); 1102 break; 1103 /* unknown option */ 1104 default: 1105 if (!silent) { 1106 printk(KERN_ERR 1107 "FAT: Unrecognized mount option \"%s\" " 1108 "or missing value\n", p); 1109 } 1110 return -EINVAL; 1111 } 1112 } 1113 /* UTF-8 doesn't provide FAT semantics */ 1114 if (!strcmp(opts->iocharset, "utf8")) { 1115 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset" 1116 " for FAT filesystems, filesystem will be case sensitive!\n"); 1117 } 1118 1119 if (opts->unicode_xlate) 1120 opts->utf8 = 0; 1121 1122 return 0; 1123 } 1124 1125 static int fat_read_root(struct inode *inode) 1126 { 1127 struct super_block *sb = inode->i_sb; 1128 struct msdos_sb_info *sbi = MSDOS_SB(sb); 1129 int error; 1130 1131 MSDOS_I(inode)->i_pos = 0; 1132 inode->i_uid = sbi->options.fs_uid; 1133 inode->i_gid = sbi->options.fs_gid; 1134 inode->i_version++; 1135 inode->i_generation = 0; 1136 inode->i_mode = (S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR; 1137 inode->i_op = sbi->dir_ops; 1138 inode->i_fop = &fat_dir_operations; 1139 if (sbi->fat_bits == 32) { 1140 MSDOS_I(inode)->i_start = sbi->root_cluster; 1141 error = fat_calc_dir_size(inode); 1142 if (error < 0) 1143 return error; 1144 } else { 1145 MSDOS_I(inode)->i_start = 0; 1146 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry); 1147 } 1148 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 1149 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 1150 MSDOS_I(inode)->i_logstart = 0; 1151 MSDOS_I(inode)->mmu_private = inode->i_size; 1152 1153 MSDOS_I(inode)->i_attrs = ATTR_NONE; 1154 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0; 1155 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0; 1156 inode->i_nlink = fat_subdirs(inode)+2; 1157 1158 return 0; 1159 } 1160 1161 /* 1162 * Read the super block of an MS-DOS FS. 1163 */ 1164 int fat_fill_super(struct super_block *sb, void *data, int silent, 1165 const struct inode_operations *fs_dir_inode_ops, int isvfat) 1166 { 1167 struct inode *root_inode = NULL; 1168 struct buffer_head *bh; 1169 struct fat_boot_sector *b; 1170 struct msdos_sb_info *sbi; 1171 u16 logical_sector_size; 1172 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors; 1173 int debug; 1174 unsigned int media; 1175 long error; 1176 char buf[50]; 1177 1178 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL); 1179 if (!sbi) 1180 return -ENOMEM; 1181 sb->s_fs_info = sbi; 1182 1183 sb->s_flags |= MS_NODIRATIME; 1184 sb->s_magic = MSDOS_SUPER_MAGIC; 1185 sb->s_op = &fat_sops; 1186 sb->s_export_op = &fat_export_ops; 1187 sbi->dir_ops = fs_dir_inode_ops; 1188 1189 error = parse_options(data, isvfat, silent, &debug, &sbi->options); 1190 if (error) 1191 goto out_fail; 1192 1193 error = -EIO; 1194 sb_min_blocksize(sb, 512); 1195 bh = sb_bread(sb, 0); 1196 if (bh == NULL) { 1197 printk(KERN_ERR "FAT: unable to read boot sector\n"); 1198 goto out_fail; 1199 } 1200 1201 b = (struct fat_boot_sector *) bh->b_data; 1202 if (!b->reserved) { 1203 if (!silent) 1204 printk(KERN_ERR "FAT: bogus number of reserved sectors\n"); 1205 brelse(bh); 1206 goto out_invalid; 1207 } 1208 if (!b->fats) { 1209 if (!silent) 1210 printk(KERN_ERR "FAT: bogus number of FAT structure\n"); 1211 brelse(bh); 1212 goto out_invalid; 1213 } 1214 1215 /* 1216 * Earlier we checked here that b->secs_track and b->head are nonzero, 1217 * but it turns out valid FAT filesystems can have zero there. 1218 */ 1219 1220 media = b->media; 1221 if (!FAT_VALID_MEDIA(media)) { 1222 if (!silent) 1223 printk(KERN_ERR "FAT: invalid media value (0x%02x)\n", 1224 media); 1225 brelse(bh); 1226 goto out_invalid; 1227 } 1228 logical_sector_size = 1229 le16_to_cpu(get_unaligned((__le16 *)&b->sector_size)); 1230 if (!is_power_of_2(logical_sector_size) 1231 || (logical_sector_size < 512) 1232 || (PAGE_CACHE_SIZE < logical_sector_size)) { 1233 if (!silent) 1234 printk(KERN_ERR "FAT: bogus logical sector size %u\n", 1235 logical_sector_size); 1236 brelse(bh); 1237 goto out_invalid; 1238 } 1239 sbi->sec_per_clus = b->sec_per_clus; 1240 if (!is_power_of_2(sbi->sec_per_clus)) { 1241 if (!silent) 1242 printk(KERN_ERR "FAT: bogus sectors per cluster %u\n", 1243 sbi->sec_per_clus); 1244 brelse(bh); 1245 goto out_invalid; 1246 } 1247 1248 if (logical_sector_size < sb->s_blocksize) { 1249 printk(KERN_ERR "FAT: logical sector size too small for device" 1250 " (logical sector size = %u)\n", logical_sector_size); 1251 brelse(bh); 1252 goto out_fail; 1253 } 1254 if (logical_sector_size > sb->s_blocksize) { 1255 brelse(bh); 1256 1257 if (!sb_set_blocksize(sb, logical_sector_size)) { 1258 printk(KERN_ERR "FAT: unable to set blocksize %u\n", 1259 logical_sector_size); 1260 goto out_fail; 1261 } 1262 bh = sb_bread(sb, 0); 1263 if (bh == NULL) { 1264 printk(KERN_ERR "FAT: unable to read boot sector" 1265 " (logical sector size = %lu)\n", 1266 sb->s_blocksize); 1267 goto out_fail; 1268 } 1269 b = (struct fat_boot_sector *) bh->b_data; 1270 } 1271 1272 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus; 1273 sbi->cluster_bits = ffs(sbi->cluster_size) - 1; 1274 sbi->fats = b->fats; 1275 sbi->fat_bits = 0; /* Don't know yet */ 1276 sbi->fat_start = le16_to_cpu(b->reserved); 1277 sbi->fat_length = le16_to_cpu(b->fat_length); 1278 sbi->root_cluster = 0; 1279 sbi->free_clusters = -1; /* Don't know yet */ 1280 sbi->prev_free = FAT_START_ENT; 1281 1282 if (!sbi->fat_length && b->fat32_length) { 1283 struct fat_boot_fsinfo *fsinfo; 1284 struct buffer_head *fsinfo_bh; 1285 1286 /* Must be FAT32 */ 1287 sbi->fat_bits = 32; 1288 sbi->fat_length = le32_to_cpu(b->fat32_length); 1289 sbi->root_cluster = le32_to_cpu(b->root_cluster); 1290 1291 sb->s_maxbytes = 0xffffffff; 1292 1293 /* MC - if info_sector is 0, don't multiply by 0 */ 1294 sbi->fsinfo_sector = le16_to_cpu(b->info_sector); 1295 if (sbi->fsinfo_sector == 0) 1296 sbi->fsinfo_sector = 1; 1297 1298 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector); 1299 if (fsinfo_bh == NULL) { 1300 printk(KERN_ERR "FAT: bread failed, FSINFO block" 1301 " (sector = %lu)\n", sbi->fsinfo_sector); 1302 brelse(bh); 1303 goto out_fail; 1304 } 1305 1306 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data; 1307 if (!IS_FSINFO(fsinfo)) { 1308 printk(KERN_WARNING 1309 "FAT: Did not find valid FSINFO signature.\n" 1310 " Found signature1 0x%08x signature2 0x%08x" 1311 " (sector = %lu)\n", 1312 le32_to_cpu(fsinfo->signature1), 1313 le32_to_cpu(fsinfo->signature2), 1314 sbi->fsinfo_sector); 1315 } else { 1316 if (sbi->options.usefree) 1317 sbi->free_clusters = 1318 le32_to_cpu(fsinfo->free_clusters); 1319 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster); 1320 } 1321 1322 brelse(fsinfo_bh); 1323 } 1324 1325 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry); 1326 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1; 1327 1328 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length; 1329 sbi->dir_entries = 1330 le16_to_cpu(get_unaligned((__le16 *)&b->dir_entries)); 1331 if (sbi->dir_entries & (sbi->dir_per_block - 1)) { 1332 if (!silent) 1333 printk(KERN_ERR "FAT: bogus directroy-entries per block" 1334 " (%u)\n", sbi->dir_entries); 1335 brelse(bh); 1336 goto out_invalid; 1337 } 1338 1339 rootdir_sectors = sbi->dir_entries 1340 * sizeof(struct msdos_dir_entry) / sb->s_blocksize; 1341 sbi->data_start = sbi->dir_start + rootdir_sectors; 1342 total_sectors = le16_to_cpu(get_unaligned((__le16 *)&b->sectors)); 1343 if (total_sectors == 0) 1344 total_sectors = le32_to_cpu(b->total_sect); 1345 1346 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus; 1347 1348 if (sbi->fat_bits != 32) 1349 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12; 1350 1351 /* check that FAT table does not overflow */ 1352 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits; 1353 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT); 1354 if (total_clusters > MAX_FAT(sb)) { 1355 if (!silent) 1356 printk(KERN_ERR "FAT: count of clusters too big (%u)\n", 1357 total_clusters); 1358 brelse(bh); 1359 goto out_invalid; 1360 } 1361 1362 sbi->max_cluster = total_clusters + FAT_START_ENT; 1363 /* check the free_clusters, it's not necessarily correct */ 1364 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters) 1365 sbi->free_clusters = -1; 1366 /* check the prev_free, it's not necessarily correct */ 1367 sbi->prev_free %= sbi->max_cluster; 1368 if (sbi->prev_free < FAT_START_ENT) 1369 sbi->prev_free = FAT_START_ENT; 1370 1371 brelse(bh); 1372 1373 /* set up enough so that it can read an inode */ 1374 fat_hash_init(sb); 1375 fat_ent_access_init(sb); 1376 1377 /* 1378 * The low byte of FAT's first entry must have same value with 1379 * media-field. But in real world, too many devices is 1380 * writing wrong value. So, removed that validity check. 1381 * 1382 * if (FAT_FIRST_ENT(sb, media) != first) 1383 */ 1384 1385 error = -EINVAL; 1386 sprintf(buf, "cp%d", sbi->options.codepage); 1387 sbi->nls_disk = load_nls(buf); 1388 if (!sbi->nls_disk) { 1389 printk(KERN_ERR "FAT: codepage %s not found\n", buf); 1390 goto out_fail; 1391 } 1392 1393 /* FIXME: utf8 is using iocharset for upper/lower conversion */ 1394 if (sbi->options.isvfat) { 1395 sbi->nls_io = load_nls(sbi->options.iocharset); 1396 if (!sbi->nls_io) { 1397 printk(KERN_ERR "FAT: IO charset %s not found\n", 1398 sbi->options.iocharset); 1399 goto out_fail; 1400 } 1401 } 1402 1403 error = -ENOMEM; 1404 root_inode = new_inode(sb); 1405 if (!root_inode) 1406 goto out_fail; 1407 root_inode->i_ino = MSDOS_ROOT_INO; 1408 root_inode->i_version = 1; 1409 error = fat_read_root(root_inode); 1410 if (error < 0) 1411 goto out_fail; 1412 error = -ENOMEM; 1413 insert_inode_hash(root_inode); 1414 sb->s_root = d_alloc_root(root_inode); 1415 if (!sb->s_root) { 1416 printk(KERN_ERR "FAT: get root inode failed\n"); 1417 goto out_fail; 1418 } 1419 1420 return 0; 1421 1422 out_invalid: 1423 error = -EINVAL; 1424 if (!silent) 1425 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem" 1426 " on dev %s.\n", sb->s_id); 1427 1428 out_fail: 1429 if (root_inode) 1430 iput(root_inode); 1431 if (sbi->nls_io) 1432 unload_nls(sbi->nls_io); 1433 if (sbi->nls_disk) 1434 unload_nls(sbi->nls_disk); 1435 if (sbi->options.iocharset != fat_default_iocharset) 1436 kfree(sbi->options.iocharset); 1437 sb->s_fs_info = NULL; 1438 kfree(sbi); 1439 return error; 1440 } 1441 1442 EXPORT_SYMBOL_GPL(fat_fill_super); 1443 1444 /* 1445 * helper function for fat_flush_inodes. This writes both the inode 1446 * and the file data blocks, waiting for in flight data blocks before 1447 * the start of the call. It does not wait for any io started 1448 * during the call 1449 */ 1450 static int writeback_inode(struct inode *inode) 1451 { 1452 1453 int ret; 1454 struct address_space *mapping = inode->i_mapping; 1455 struct writeback_control wbc = { 1456 .sync_mode = WB_SYNC_NONE, 1457 .nr_to_write = 0, 1458 }; 1459 /* if we used WB_SYNC_ALL, sync_inode waits for the io for the 1460 * inode to finish. So WB_SYNC_NONE is sent down to sync_inode 1461 * and filemap_fdatawrite is used for the data blocks 1462 */ 1463 ret = sync_inode(inode, &wbc); 1464 if (!ret) 1465 ret = filemap_fdatawrite(mapping); 1466 return ret; 1467 } 1468 1469 /* 1470 * write data and metadata corresponding to i1 and i2. The io is 1471 * started but we do not wait for any of it to finish. 1472 * 1473 * filemap_flush is used for the block device, so if there is a dirty 1474 * page for a block already in flight, we will not wait and start the 1475 * io over again 1476 */ 1477 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2) 1478 { 1479 int ret = 0; 1480 if (!MSDOS_SB(sb)->options.flush) 1481 return 0; 1482 if (i1) 1483 ret = writeback_inode(i1); 1484 if (!ret && i2) 1485 ret = writeback_inode(i2); 1486 if (!ret) { 1487 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping; 1488 ret = filemap_flush(mapping); 1489 } 1490 return ret; 1491 } 1492 EXPORT_SYMBOL_GPL(fat_flush_inodes); 1493 1494 static int __init init_fat_fs(void) 1495 { 1496 int err; 1497 1498 err = fat_cache_init(); 1499 if (err) 1500 return err; 1501 1502 err = fat_init_inodecache(); 1503 if (err) 1504 goto failed; 1505 1506 return 0; 1507 1508 failed: 1509 fat_cache_destroy(); 1510 return err; 1511 } 1512 1513 static void __exit exit_fat_fs(void) 1514 { 1515 fat_cache_destroy(); 1516 fat_destroy_inodecache(); 1517 } 1518 1519 module_init(init_fat_fs) 1520 module_exit(exit_fat_fs) 1521 1522 MODULE_LICENSE("GPL"); 1523