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/pagemap.h> 20 #include <linux/mpage.h> 21 #include <linux/buffer_head.h> 22 #include <linux/exportfs.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 <linux/hash.h> 30 #include <asm/unaligned.h> 31 #include "fat.h" 32 33 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET 34 /* if user don't select VFAT, this is undefined. */ 35 #define CONFIG_FAT_DEFAULT_IOCHARSET "" 36 #endif 37 38 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE; 39 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET; 40 41 42 static int fat_add_cluster(struct inode *inode) 43 { 44 int err, cluster; 45 46 err = fat_alloc_clusters(inode, &cluster, 1); 47 if (err) 48 return err; 49 /* FIXME: this cluster should be added after data of this 50 * cluster is writed */ 51 err = fat_chain_add(inode, cluster, 1); 52 if (err) 53 fat_free_clusters(inode, cluster); 54 return err; 55 } 56 57 static inline int __fat_get_block(struct inode *inode, sector_t iblock, 58 unsigned long *max_blocks, 59 struct buffer_head *bh_result, int create) 60 { 61 struct super_block *sb = inode->i_sb; 62 struct msdos_sb_info *sbi = MSDOS_SB(sb); 63 unsigned long mapped_blocks; 64 sector_t phys; 65 int err, offset; 66 67 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create); 68 if (err) 69 return err; 70 if (phys) { 71 map_bh(bh_result, sb, phys); 72 *max_blocks = min(mapped_blocks, *max_blocks); 73 return 0; 74 } 75 if (!create) 76 return 0; 77 78 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) { 79 fat_fs_panic(sb, "corrupted file size (i_pos %lld, %lld)", 80 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private); 81 return -EIO; 82 } 83 84 offset = (unsigned long)iblock & (sbi->sec_per_clus - 1); 85 if (!offset) { 86 /* TODO: multiple cluster allocation would be desirable. */ 87 err = fat_add_cluster(inode); 88 if (err) 89 return err; 90 } 91 /* available blocks on this cluster */ 92 mapped_blocks = sbi->sec_per_clus - offset; 93 94 *max_blocks = min(mapped_blocks, *max_blocks); 95 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits; 96 97 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create); 98 if (err) 99 return err; 100 101 BUG_ON(!phys); 102 BUG_ON(*max_blocks != mapped_blocks); 103 set_buffer_new(bh_result); 104 map_bh(bh_result, sb, phys); 105 106 return 0; 107 } 108 109 static int fat_get_block(struct inode *inode, sector_t iblock, 110 struct buffer_head *bh_result, int create) 111 { 112 struct super_block *sb = inode->i_sb; 113 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits; 114 int err; 115 116 err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create); 117 if (err) 118 return err; 119 bh_result->b_size = max_blocks << sb->s_blocksize_bits; 120 return 0; 121 } 122 123 static int fat_writepage(struct page *page, struct writeback_control *wbc) 124 { 125 return block_write_full_page(page, fat_get_block, wbc); 126 } 127 128 static int fat_writepages(struct address_space *mapping, 129 struct writeback_control *wbc) 130 { 131 return mpage_writepages(mapping, wbc, fat_get_block); 132 } 133 134 static int fat_readpage(struct file *file, struct page *page) 135 { 136 return mpage_readpage(page, fat_get_block); 137 } 138 139 static int fat_readpages(struct file *file, struct address_space *mapping, 140 struct list_head *pages, unsigned nr_pages) 141 { 142 return mpage_readpages(mapping, pages, nr_pages, fat_get_block); 143 } 144 145 static int fat_write_begin(struct file *file, struct address_space *mapping, 146 loff_t pos, unsigned len, unsigned flags, 147 struct page **pagep, void **fsdata) 148 { 149 *pagep = NULL; 150 return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata, 151 fat_get_block, 152 &MSDOS_I(mapping->host)->mmu_private); 153 } 154 155 static int fat_write_end(struct file *file, struct address_space *mapping, 156 loff_t pos, unsigned len, unsigned copied, 157 struct page *pagep, void *fsdata) 158 { 159 struct inode *inode = mapping->host; 160 int err; 161 err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata); 162 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) { 163 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC; 164 MSDOS_I(inode)->i_attrs |= ATTR_ARCH; 165 mark_inode_dirty(inode); 166 } 167 return err; 168 } 169 170 static ssize_t fat_direct_IO(int rw, struct kiocb *iocb, 171 const struct iovec *iov, 172 loff_t offset, unsigned long nr_segs) 173 { 174 struct file *file = iocb->ki_filp; 175 struct inode *inode = file->f_mapping->host; 176 177 if (rw == WRITE) { 178 /* 179 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(), 180 * so we need to update the ->mmu_private to block boundary. 181 * 182 * But we must fill the remaining area or hole by nul for 183 * updating ->mmu_private. 184 * 185 * Return 0, and fallback to normal buffered write. 186 */ 187 loff_t size = offset + iov_length(iov, nr_segs); 188 if (MSDOS_I(inode)->mmu_private < size) 189 return 0; 190 } 191 192 /* 193 * FAT need to use the DIO_LOCKING for avoiding the race 194 * condition of fat_get_block() and ->truncate(). 195 */ 196 return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov, 197 offset, nr_segs, fat_get_block, NULL); 198 } 199 200 static sector_t _fat_bmap(struct address_space *mapping, sector_t block) 201 { 202 sector_t blocknr; 203 204 /* fat_get_cluster() assumes the requested blocknr isn't truncated. */ 205 down_read(&mapping->host->i_alloc_sem); 206 blocknr = generic_block_bmap(mapping, block, fat_get_block); 207 up_read(&mapping->host->i_alloc_sem); 208 209 return blocknr; 210 } 211 212 static const struct address_space_operations fat_aops = { 213 .readpage = fat_readpage, 214 .readpages = fat_readpages, 215 .writepage = fat_writepage, 216 .writepages = fat_writepages, 217 .sync_page = block_sync_page, 218 .write_begin = fat_write_begin, 219 .write_end = fat_write_end, 220 .direct_IO = fat_direct_IO, 221 .bmap = _fat_bmap 222 }; 223 224 /* 225 * New FAT inode stuff. We do the following: 226 * a) i_ino is constant and has nothing with on-disk location. 227 * b) FAT manages its own cache of directory entries. 228 * c) *This* cache is indexed by on-disk location. 229 * d) inode has an associated directory entry, all right, but 230 * it may be unhashed. 231 * e) currently entries are stored within struct inode. That should 232 * change. 233 * f) we deal with races in the following way: 234 * 1. readdir() and lookup() do FAT-dir-cache lookup. 235 * 2. rename() unhashes the F-d-c entry and rehashes it in 236 * a new place. 237 * 3. unlink() and rmdir() unhash F-d-c entry. 238 * 4. fat_write_inode() checks whether the thing is unhashed. 239 * If it is we silently return. If it isn't we do bread(), 240 * check if the location is still valid and retry if it 241 * isn't. Otherwise we do changes. 242 * 5. Spinlock is used to protect hash/unhash/location check/lookup 243 * 6. fat_clear_inode() unhashes the F-d-c entry. 244 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry 245 * and consider negative result as cache miss. 246 */ 247 248 static void fat_hash_init(struct super_block *sb) 249 { 250 struct msdos_sb_info *sbi = MSDOS_SB(sb); 251 int i; 252 253 spin_lock_init(&sbi->inode_hash_lock); 254 for (i = 0; i < FAT_HASH_SIZE; i++) 255 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]); 256 } 257 258 static inline unsigned long fat_hash(loff_t i_pos) 259 { 260 return hash_32(i_pos, FAT_HASH_BITS); 261 } 262 263 void fat_attach(struct inode *inode, loff_t i_pos) 264 { 265 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 266 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos); 267 268 spin_lock(&sbi->inode_hash_lock); 269 MSDOS_I(inode)->i_pos = i_pos; 270 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head); 271 spin_unlock(&sbi->inode_hash_lock); 272 } 273 EXPORT_SYMBOL_GPL(fat_attach); 274 275 void fat_detach(struct inode *inode) 276 { 277 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 278 spin_lock(&sbi->inode_hash_lock); 279 MSDOS_I(inode)->i_pos = 0; 280 hlist_del_init(&MSDOS_I(inode)->i_fat_hash); 281 spin_unlock(&sbi->inode_hash_lock); 282 } 283 EXPORT_SYMBOL_GPL(fat_detach); 284 285 struct inode *fat_iget(struct super_block *sb, loff_t i_pos) 286 { 287 struct msdos_sb_info *sbi = MSDOS_SB(sb); 288 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos); 289 struct hlist_node *_p; 290 struct msdos_inode_info *i; 291 struct inode *inode = NULL; 292 293 spin_lock(&sbi->inode_hash_lock); 294 hlist_for_each_entry(i, _p, head, i_fat_hash) { 295 BUG_ON(i->vfs_inode.i_sb != sb); 296 if (i->i_pos != i_pos) 297 continue; 298 inode = igrab(&i->vfs_inode); 299 if (inode) 300 break; 301 } 302 spin_unlock(&sbi->inode_hash_lock); 303 return inode; 304 } 305 306 static int is_exec(unsigned char *extension) 307 { 308 unsigned char *exe_extensions = "EXECOMBAT", *walk; 309 310 for (walk = exe_extensions; *walk; walk += 3) 311 if (!strncmp(extension, walk, 3)) 312 return 1; 313 return 0; 314 } 315 316 static int fat_calc_dir_size(struct inode *inode) 317 { 318 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 319 int ret, fclus, dclus; 320 321 inode->i_size = 0; 322 if (MSDOS_I(inode)->i_start == 0) 323 return 0; 324 325 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); 326 if (ret < 0) 327 return ret; 328 inode->i_size = (fclus + 1) << sbi->cluster_bits; 329 330 return 0; 331 } 332 333 /* doesn't deal with root inode */ 334 static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de) 335 { 336 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 337 int error; 338 339 MSDOS_I(inode)->i_pos = 0; 340 inode->i_uid = sbi->options.fs_uid; 341 inode->i_gid = sbi->options.fs_gid; 342 inode->i_version++; 343 inode->i_generation = get_seconds(); 344 345 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) { 346 inode->i_generation &= ~1; 347 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO); 348 inode->i_op = sbi->dir_ops; 349 inode->i_fop = &fat_dir_operations; 350 351 MSDOS_I(inode)->i_start = le16_to_cpu(de->start); 352 if (sbi->fat_bits == 32) 353 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16); 354 355 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 356 error = fat_calc_dir_size(inode); 357 if (error < 0) 358 return error; 359 MSDOS_I(inode)->mmu_private = inode->i_size; 360 361 inode->i_nlink = fat_subdirs(inode); 362 } else { /* not a directory */ 363 inode->i_generation |= 1; 364 inode->i_mode = fat_make_mode(sbi, de->attr, 365 ((sbi->options.showexec && !is_exec(de->name + 8)) 366 ? S_IRUGO|S_IWUGO : S_IRWXUGO)); 367 MSDOS_I(inode)->i_start = le16_to_cpu(de->start); 368 if (sbi->fat_bits == 32) 369 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16); 370 371 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 372 inode->i_size = le32_to_cpu(de->size); 373 inode->i_op = &fat_file_inode_operations; 374 inode->i_fop = &fat_file_operations; 375 inode->i_mapping->a_ops = &fat_aops; 376 MSDOS_I(inode)->mmu_private = inode->i_size; 377 } 378 if (de->attr & ATTR_SYS) { 379 if (sbi->options.sys_immutable) 380 inode->i_flags |= S_IMMUTABLE; 381 } 382 fat_save_attrs(inode, de->attr); 383 384 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 385 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 386 387 fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0); 388 if (sbi->options.isvfat) { 389 fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime, 390 de->cdate, de->ctime_cs); 391 fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 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 inode->i_size = 0; 432 fat_truncate(inode); 433 clear_inode(inode); 434 } 435 436 static void fat_clear_inode(struct inode *inode) 437 { 438 fat_cache_inval_inode(inode); 439 fat_detach(inode); 440 } 441 442 static void fat_write_super(struct super_block *sb) 443 { 444 sb->s_dirt = 0; 445 446 if (!(sb->s_flags & MS_RDONLY)) 447 fat_clusters_flush(sb); 448 } 449 450 static void fat_put_super(struct super_block *sb) 451 { 452 struct msdos_sb_info *sbi = MSDOS_SB(sb); 453 454 if (sbi->nls_disk) { 455 unload_nls(sbi->nls_disk); 456 sbi->nls_disk = NULL; 457 sbi->options.codepage = fat_default_codepage; 458 } 459 if (sbi->nls_io) { 460 unload_nls(sbi->nls_io); 461 sbi->nls_io = NULL; 462 } 463 if (sbi->options.iocharset != fat_default_iocharset) { 464 kfree(sbi->options.iocharset); 465 sbi->options.iocharset = fat_default_iocharset; 466 } 467 468 sb->s_fs_info = NULL; 469 kfree(sbi); 470 } 471 472 static struct kmem_cache *fat_inode_cachep; 473 474 static struct inode *fat_alloc_inode(struct super_block *sb) 475 { 476 struct msdos_inode_info *ei; 477 ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS); 478 if (!ei) 479 return NULL; 480 return &ei->vfs_inode; 481 } 482 483 static void fat_destroy_inode(struct inode *inode) 484 { 485 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode)); 486 } 487 488 static void init_once(void *foo) 489 { 490 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo; 491 492 spin_lock_init(&ei->cache_lru_lock); 493 ei->nr_caches = 0; 494 ei->cache_valid_id = FAT_CACHE_VALID + 1; 495 INIT_LIST_HEAD(&ei->cache_lru); 496 INIT_HLIST_NODE(&ei->i_fat_hash); 497 inode_init_once(&ei->vfs_inode); 498 } 499 500 static int __init fat_init_inodecache(void) 501 { 502 fat_inode_cachep = kmem_cache_create("fat_inode_cache", 503 sizeof(struct msdos_inode_info), 504 0, (SLAB_RECLAIM_ACCOUNT| 505 SLAB_MEM_SPREAD), 506 init_once); 507 if (fat_inode_cachep == NULL) 508 return -ENOMEM; 509 return 0; 510 } 511 512 static void __exit fat_destroy_inodecache(void) 513 { 514 kmem_cache_destroy(fat_inode_cachep); 515 } 516 517 static int fat_remount(struct super_block *sb, int *flags, char *data) 518 { 519 struct msdos_sb_info *sbi = MSDOS_SB(sb); 520 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME); 521 return 0; 522 } 523 524 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf) 525 { 526 struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb); 527 528 /* If the count of free cluster is still unknown, counts it here. */ 529 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) { 530 int err = fat_count_free_clusters(dentry->d_sb); 531 if (err) 532 return err; 533 } 534 535 buf->f_type = dentry->d_sb->s_magic; 536 buf->f_bsize = sbi->cluster_size; 537 buf->f_blocks = sbi->max_cluster - FAT_START_ENT; 538 buf->f_bfree = sbi->free_clusters; 539 buf->f_bavail = sbi->free_clusters; 540 buf->f_namelen = sbi->options.isvfat ? 260 : 12; 541 542 return 0; 543 } 544 545 static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi, 546 struct inode *inode) 547 { 548 loff_t i_pos; 549 #if BITS_PER_LONG == 32 550 spin_lock(&sbi->inode_hash_lock); 551 #endif 552 i_pos = MSDOS_I(inode)->i_pos; 553 #if BITS_PER_LONG == 32 554 spin_unlock(&sbi->inode_hash_lock); 555 #endif 556 return i_pos; 557 } 558 559 static int fat_write_inode(struct inode *inode, int wait) 560 { 561 struct super_block *sb = inode->i_sb; 562 struct msdos_sb_info *sbi = MSDOS_SB(sb); 563 struct buffer_head *bh; 564 struct msdos_dir_entry *raw_entry; 565 loff_t i_pos; 566 int err; 567 568 if (inode->i_ino == MSDOS_ROOT_INO) 569 return 0; 570 571 retry: 572 i_pos = fat_i_pos_read(sbi, inode); 573 if (!i_pos) 574 return 0; 575 576 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 return -EIO; 581 } 582 spin_lock(&sbi->inode_hash_lock); 583 if (i_pos != MSDOS_I(inode)->i_pos) { 584 spin_unlock(&sbi->inode_hash_lock); 585 brelse(bh); 586 goto retry; 587 } 588 589 raw_entry = &((struct msdos_dir_entry *) (bh->b_data)) 590 [i_pos & (sbi->dir_per_block - 1)]; 591 if (S_ISDIR(inode->i_mode)) 592 raw_entry->size = 0; 593 else 594 raw_entry->size = cpu_to_le32(inode->i_size); 595 raw_entry->attr = fat_make_attrs(inode); 596 raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart); 597 raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16); 598 fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time, 599 &raw_entry->date, NULL); 600 if (sbi->options.isvfat) { 601 __le16 atime; 602 fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime, 603 &raw_entry->cdate, &raw_entry->ctime_cs); 604 fat_time_unix2fat(sbi, &inode->i_atime, &atime, 605 &raw_entry->adate, NULL); 606 } 607 spin_unlock(&sbi->inode_hash_lock); 608 mark_buffer_dirty(bh); 609 err = 0; 610 if (wait) 611 err = sync_dirty_buffer(bh); 612 brelse(bh); 613 return err; 614 } 615 616 int fat_sync_inode(struct inode *inode) 617 { 618 return fat_write_inode(inode, 1); 619 } 620 621 EXPORT_SYMBOL_GPL(fat_sync_inode); 622 623 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt); 624 static const struct super_operations fat_sops = { 625 .alloc_inode = fat_alloc_inode, 626 .destroy_inode = fat_destroy_inode, 627 .write_inode = fat_write_inode, 628 .delete_inode = fat_delete_inode, 629 .put_super = fat_put_super, 630 .write_super = fat_write_super, 631 .statfs = fat_statfs, 632 .clear_inode = fat_clear_inode, 633 .remount_fs = fat_remount, 634 635 .show_options = fat_show_options, 636 }; 637 638 /* 639 * a FAT file handle with fhtype 3 is 640 * 0/ i_ino - for fast, reliable lookup if still in the cache 641 * 1/ i_generation - to see if i_ino is still valid 642 * bit 0 == 0 iff directory 643 * 2/ i_pos(8-39) - if ino has changed, but still in cache 644 * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos 645 * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc 646 * 647 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum 648 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits 649 * of i_logstart is used to store the directory entry offset. 650 */ 651 652 static struct dentry *fat_fh_to_dentry(struct super_block *sb, 653 struct fid *fid, int fh_len, int fh_type) 654 { 655 struct inode *inode = NULL; 656 struct dentry *result; 657 u32 *fh = fid->raw; 658 659 if (fh_len < 5 || fh_type != 3) 660 return NULL; 661 662 inode = ilookup(sb, fh[0]); 663 if (!inode || inode->i_generation != fh[1]) { 664 if (inode) 665 iput(inode); 666 inode = NULL; 667 } 668 if (!inode) { 669 loff_t i_pos; 670 int i_logstart = fh[3] & 0x0fffffff; 671 672 i_pos = (loff_t)fh[2] << 8; 673 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28); 674 675 /* try 2 - see if i_pos is in F-d-c 676 * require i_logstart to be the same 677 * Will fail if you truncate and then re-write 678 */ 679 680 inode = fat_iget(sb, i_pos); 681 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) { 682 iput(inode); 683 inode = NULL; 684 } 685 } 686 687 /* 688 * For now, do nothing if the inode is not found. 689 * 690 * What we could do is: 691 * 692 * - follow the file starting at fh[4], and record the ".." entry, 693 * and the name of the fh[2] entry. 694 * - then follow the ".." file finding the next step up. 695 * 696 * This way we build a path to the root of the tree. If this works, we 697 * lookup the path and so get this inode into the cache. Finally try 698 * the fat_iget lookup again. If that fails, then we are totally out 699 * of luck. But all that is for another day 700 */ 701 result = d_obtain_alias(inode); 702 if (!IS_ERR(result)) 703 result->d_op = sb->s_root->d_op; 704 return result; 705 } 706 707 static int 708 fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable) 709 { 710 int len = *lenp; 711 struct inode *inode = de->d_inode; 712 u32 ipos_h, ipos_m, ipos_l; 713 714 if (len < 5) 715 return 255; /* no room */ 716 717 ipos_h = MSDOS_I(inode)->i_pos >> 8; 718 ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24; 719 ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28; 720 *lenp = 5; 721 fh[0] = inode->i_ino; 722 fh[1] = inode->i_generation; 723 fh[2] = ipos_h; 724 fh[3] = ipos_m | MSDOS_I(inode)->i_logstart; 725 spin_lock(&de->d_lock); 726 fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart; 727 spin_unlock(&de->d_lock); 728 return 3; 729 } 730 731 static struct dentry *fat_get_parent(struct dentry *child) 732 { 733 struct super_block *sb = child->d_sb; 734 struct buffer_head *bh; 735 struct msdos_dir_entry *de; 736 loff_t i_pos; 737 struct dentry *parent; 738 struct inode *inode; 739 int err; 740 741 lock_super(sb); 742 743 err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos); 744 if (err) { 745 parent = ERR_PTR(err); 746 goto out; 747 } 748 inode = fat_build_inode(sb, de, i_pos); 749 brelse(bh); 750 751 parent = d_obtain_alias(inode); 752 if (!IS_ERR(parent)) 753 parent->d_op = sb->s_root->d_op; 754 out: 755 unlock_super(sb); 756 757 return parent; 758 } 759 760 static const struct export_operations fat_export_ops = { 761 .encode_fh = fat_encode_fh, 762 .fh_to_dentry = fat_fh_to_dentry, 763 .get_parent = fat_get_parent, 764 }; 765 766 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt) 767 { 768 struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb); 769 struct fat_mount_options *opts = &sbi->options; 770 int isvfat = opts->isvfat; 771 772 if (opts->fs_uid != 0) 773 seq_printf(m, ",uid=%u", opts->fs_uid); 774 if (opts->fs_gid != 0) 775 seq_printf(m, ",gid=%u", opts->fs_gid); 776 seq_printf(m, ",fmask=%04o", opts->fs_fmask); 777 seq_printf(m, ",dmask=%04o", opts->fs_dmask); 778 if (opts->allow_utime) 779 seq_printf(m, ",allow_utime=%04o", opts->allow_utime); 780 if (sbi->nls_disk) 781 seq_printf(m, ",codepage=%s", sbi->nls_disk->charset); 782 if (isvfat) { 783 if (sbi->nls_io) 784 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset); 785 786 switch (opts->shortname) { 787 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95: 788 seq_puts(m, ",shortname=win95"); 789 break; 790 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT: 791 seq_puts(m, ",shortname=winnt"); 792 break; 793 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95: 794 seq_puts(m, ",shortname=mixed"); 795 break; 796 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95: 797 /* seq_puts(m, ",shortname=lower"); */ 798 break; 799 default: 800 seq_puts(m, ",shortname=unknown"); 801 break; 802 } 803 } 804 if (opts->name_check != 'n') 805 seq_printf(m, ",check=%c", opts->name_check); 806 if (opts->usefree) 807 seq_puts(m, ",usefree"); 808 if (opts->quiet) 809 seq_puts(m, ",quiet"); 810 if (opts->showexec) 811 seq_puts(m, ",showexec"); 812 if (opts->sys_immutable) 813 seq_puts(m, ",sys_immutable"); 814 if (!isvfat) { 815 if (opts->dotsOK) 816 seq_puts(m, ",dotsOK=yes"); 817 if (opts->nocase) 818 seq_puts(m, ",nocase"); 819 } else { 820 if (opts->utf8) 821 seq_puts(m, ",utf8"); 822 if (opts->unicode_xlate) 823 seq_puts(m, ",uni_xlate"); 824 if (!opts->numtail) 825 seq_puts(m, ",nonumtail"); 826 if (opts->rodir) 827 seq_puts(m, ",rodir"); 828 } 829 if (opts->flush) 830 seq_puts(m, ",flush"); 831 if (opts->tz_utc) 832 seq_puts(m, ",tz=UTC"); 833 834 return 0; 835 } 836 837 enum { 838 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid, 839 Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage, 840 Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug, 841 Opt_immutable, Opt_dots, Opt_nodots, 842 Opt_charset, Opt_shortname_lower, Opt_shortname_win95, 843 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes, 844 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes, 845 Opt_obsolate, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err, 846 }; 847 848 static const match_table_t fat_tokens = { 849 {Opt_check_r, "check=relaxed"}, 850 {Opt_check_s, "check=strict"}, 851 {Opt_check_n, "check=normal"}, 852 {Opt_check_r, "check=r"}, 853 {Opt_check_s, "check=s"}, 854 {Opt_check_n, "check=n"}, 855 {Opt_uid, "uid=%u"}, 856 {Opt_gid, "gid=%u"}, 857 {Opt_umask, "umask=%o"}, 858 {Opt_dmask, "dmask=%o"}, 859 {Opt_fmask, "fmask=%o"}, 860 {Opt_allow_utime, "allow_utime=%o"}, 861 {Opt_codepage, "codepage=%u"}, 862 {Opt_usefree, "usefree"}, 863 {Opt_nocase, "nocase"}, 864 {Opt_quiet, "quiet"}, 865 {Opt_showexec, "showexec"}, 866 {Opt_debug, "debug"}, 867 {Opt_immutable, "sys_immutable"}, 868 {Opt_obsolate, "conv=binary"}, 869 {Opt_obsolate, "conv=text"}, 870 {Opt_obsolate, "conv=auto"}, 871 {Opt_obsolate, "conv=b"}, 872 {Opt_obsolate, "conv=t"}, 873 {Opt_obsolate, "conv=a"}, 874 {Opt_obsolate, "fat=%u"}, 875 {Opt_obsolate, "blocksize=%u"}, 876 {Opt_obsolate, "cvf_format=%20s"}, 877 {Opt_obsolate, "cvf_options=%100s"}, 878 {Opt_obsolate, "posix"}, 879 {Opt_flush, "flush"}, 880 {Opt_tz_utc, "tz=UTC"}, 881 {Opt_err, NULL}, 882 }; 883 static const match_table_t msdos_tokens = { 884 {Opt_nodots, "nodots"}, 885 {Opt_nodots, "dotsOK=no"}, 886 {Opt_dots, "dots"}, 887 {Opt_dots, "dotsOK=yes"}, 888 {Opt_err, NULL} 889 }; 890 static const match_table_t vfat_tokens = { 891 {Opt_charset, "iocharset=%s"}, 892 {Opt_shortname_lower, "shortname=lower"}, 893 {Opt_shortname_win95, "shortname=win95"}, 894 {Opt_shortname_winnt, "shortname=winnt"}, 895 {Opt_shortname_mixed, "shortname=mixed"}, 896 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */ 897 {Opt_utf8_no, "utf8=no"}, 898 {Opt_utf8_no, "utf8=false"}, 899 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */ 900 {Opt_utf8_yes, "utf8=yes"}, 901 {Opt_utf8_yes, "utf8=true"}, 902 {Opt_utf8_yes, "utf8"}, 903 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */ 904 {Opt_uni_xl_no, "uni_xlate=no"}, 905 {Opt_uni_xl_no, "uni_xlate=false"}, 906 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */ 907 {Opt_uni_xl_yes, "uni_xlate=yes"}, 908 {Opt_uni_xl_yes, "uni_xlate=true"}, 909 {Opt_uni_xl_yes, "uni_xlate"}, 910 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */ 911 {Opt_nonumtail_no, "nonumtail=no"}, 912 {Opt_nonumtail_no, "nonumtail=false"}, 913 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */ 914 {Opt_nonumtail_yes, "nonumtail=yes"}, 915 {Opt_nonumtail_yes, "nonumtail=true"}, 916 {Opt_nonumtail_yes, "nonumtail"}, 917 {Opt_rodir, "rodir"}, 918 {Opt_err, NULL} 919 }; 920 921 static int parse_options(char *options, int is_vfat, int silent, int *debug, 922 struct fat_mount_options *opts) 923 { 924 char *p; 925 substring_t args[MAX_OPT_ARGS]; 926 int option; 927 char *iocharset; 928 929 opts->isvfat = is_vfat; 930 931 opts->fs_uid = current_uid(); 932 opts->fs_gid = current_gid(); 933 opts->fs_fmask = opts->fs_dmask = current->fs->umask; 934 opts->allow_utime = -1; 935 opts->codepage = fat_default_codepage; 936 opts->iocharset = fat_default_iocharset; 937 if (is_vfat) { 938 opts->shortname = VFAT_SFN_DISPLAY_LOWER|VFAT_SFN_CREATE_WIN95; 939 opts->rodir = 0; 940 } else { 941 opts->shortname = 0; 942 opts->rodir = 1; 943 } 944 opts->name_check = 'n'; 945 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0; 946 opts->utf8 = opts->unicode_xlate = 0; 947 opts->numtail = 1; 948 opts->usefree = opts->nocase = 0; 949 opts->tz_utc = 0; 950 *debug = 0; 951 952 if (!options) 953 goto out; 954 955 while ((p = strsep(&options, ",")) != NULL) { 956 int token; 957 if (!*p) 958 continue; 959 960 token = match_token(p, fat_tokens, args); 961 if (token == Opt_err) { 962 if (is_vfat) 963 token = match_token(p, vfat_tokens, args); 964 else 965 token = match_token(p, msdos_tokens, args); 966 } 967 switch (token) { 968 case Opt_check_s: 969 opts->name_check = 's'; 970 break; 971 case Opt_check_r: 972 opts->name_check = 'r'; 973 break; 974 case Opt_check_n: 975 opts->name_check = 'n'; 976 break; 977 case Opt_usefree: 978 opts->usefree = 1; 979 break; 980 case Opt_nocase: 981 if (!is_vfat) 982 opts->nocase = 1; 983 else { 984 /* for backward compatibility */ 985 opts->shortname = VFAT_SFN_DISPLAY_WIN95 986 | VFAT_SFN_CREATE_WIN95; 987 } 988 break; 989 case Opt_quiet: 990 opts->quiet = 1; 991 break; 992 case Opt_showexec: 993 opts->showexec = 1; 994 break; 995 case Opt_debug: 996 *debug = 1; 997 break; 998 case Opt_immutable: 999 opts->sys_immutable = 1; 1000 break; 1001 case Opt_uid: 1002 if (match_int(&args[0], &option)) 1003 return 0; 1004 opts->fs_uid = option; 1005 break; 1006 case Opt_gid: 1007 if (match_int(&args[0], &option)) 1008 return 0; 1009 opts->fs_gid = option; 1010 break; 1011 case Opt_umask: 1012 if (match_octal(&args[0], &option)) 1013 return 0; 1014 opts->fs_fmask = opts->fs_dmask = option; 1015 break; 1016 case Opt_dmask: 1017 if (match_octal(&args[0], &option)) 1018 return 0; 1019 opts->fs_dmask = option; 1020 break; 1021 case Opt_fmask: 1022 if (match_octal(&args[0], &option)) 1023 return 0; 1024 opts->fs_fmask = option; 1025 break; 1026 case Opt_allow_utime: 1027 if (match_octal(&args[0], &option)) 1028 return 0; 1029 opts->allow_utime = option & (S_IWGRP | S_IWOTH); 1030 break; 1031 case Opt_codepage: 1032 if (match_int(&args[0], &option)) 1033 return 0; 1034 opts->codepage = option; 1035 break; 1036 case Opt_flush: 1037 opts->flush = 1; 1038 break; 1039 case Opt_tz_utc: 1040 opts->tz_utc = 1; 1041 break; 1042 1043 /* msdos specific */ 1044 case Opt_dots: 1045 opts->dotsOK = 1; 1046 break; 1047 case Opt_nodots: 1048 opts->dotsOK = 0; 1049 break; 1050 1051 /* vfat specific */ 1052 case Opt_charset: 1053 if (opts->iocharset != fat_default_iocharset) 1054 kfree(opts->iocharset); 1055 iocharset = match_strdup(&args[0]); 1056 if (!iocharset) 1057 return -ENOMEM; 1058 opts->iocharset = iocharset; 1059 break; 1060 case Opt_shortname_lower: 1061 opts->shortname = VFAT_SFN_DISPLAY_LOWER 1062 | VFAT_SFN_CREATE_WIN95; 1063 break; 1064 case Opt_shortname_win95: 1065 opts->shortname = VFAT_SFN_DISPLAY_WIN95 1066 | VFAT_SFN_CREATE_WIN95; 1067 break; 1068 case Opt_shortname_winnt: 1069 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1070 | VFAT_SFN_CREATE_WINNT; 1071 break; 1072 case Opt_shortname_mixed: 1073 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1074 | VFAT_SFN_CREATE_WIN95; 1075 break; 1076 case Opt_utf8_no: /* 0 or no or false */ 1077 opts->utf8 = 0; 1078 break; 1079 case Opt_utf8_yes: /* empty or 1 or yes or true */ 1080 opts->utf8 = 1; 1081 break; 1082 case Opt_uni_xl_no: /* 0 or no or false */ 1083 opts->unicode_xlate = 0; 1084 break; 1085 case Opt_uni_xl_yes: /* empty or 1 or yes or true */ 1086 opts->unicode_xlate = 1; 1087 break; 1088 case Opt_nonumtail_no: /* 0 or no or false */ 1089 opts->numtail = 1; /* negated option */ 1090 break; 1091 case Opt_nonumtail_yes: /* empty or 1 or yes or true */ 1092 opts->numtail = 0; /* negated option */ 1093 break; 1094 case Opt_rodir: 1095 opts->rodir = 1; 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 1114 out: 1115 /* UTF-8 doesn't provide FAT semantics */ 1116 if (!strcmp(opts->iocharset, "utf8")) { 1117 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset" 1118 " for FAT filesystems, filesystem will be " 1119 "case sensitive!\n"); 1120 } 1121 1122 /* If user doesn't specify allow_utime, it's initialized from dmask. */ 1123 if (opts->allow_utime == (unsigned short)-1) 1124 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH); 1125 if (opts->unicode_xlate) 1126 opts->utf8 = 0; 1127 1128 return 0; 1129 } 1130 1131 static int fat_read_root(struct inode *inode) 1132 { 1133 struct super_block *sb = inode->i_sb; 1134 struct msdos_sb_info *sbi = MSDOS_SB(sb); 1135 int error; 1136 1137 MSDOS_I(inode)->i_pos = 0; 1138 inode->i_uid = sbi->options.fs_uid; 1139 inode->i_gid = sbi->options.fs_gid; 1140 inode->i_version++; 1141 inode->i_generation = 0; 1142 inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO); 1143 inode->i_op = sbi->dir_ops; 1144 inode->i_fop = &fat_dir_operations; 1145 if (sbi->fat_bits == 32) { 1146 MSDOS_I(inode)->i_start = sbi->root_cluster; 1147 error = fat_calc_dir_size(inode); 1148 if (error < 0) 1149 return error; 1150 } else { 1151 MSDOS_I(inode)->i_start = 0; 1152 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry); 1153 } 1154 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 1155 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 1156 MSDOS_I(inode)->i_logstart = 0; 1157 MSDOS_I(inode)->mmu_private = inode->i_size; 1158 1159 fat_save_attrs(inode, ATTR_DIR); 1160 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0; 1161 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0; 1162 inode->i_nlink = fat_subdirs(inode)+2; 1163 1164 return 0; 1165 } 1166 1167 /* 1168 * Read the super block of an MS-DOS FS. 1169 */ 1170 int fat_fill_super(struct super_block *sb, void *data, int silent, 1171 const struct inode_operations *fs_dir_inode_ops, int isvfat) 1172 { 1173 struct inode *root_inode = NULL; 1174 struct buffer_head *bh; 1175 struct fat_boot_sector *b; 1176 struct msdos_sb_info *sbi; 1177 u16 logical_sector_size; 1178 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors; 1179 int debug; 1180 unsigned int media; 1181 long error; 1182 char buf[50]; 1183 1184 /* 1185 * GFP_KERNEL is ok here, because while we do hold the 1186 * supeblock lock, memory pressure can't call back into 1187 * the filesystem, since we're only just about to mount 1188 * it and have no inodes etc active! 1189 */ 1190 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL); 1191 if (!sbi) 1192 return -ENOMEM; 1193 sb->s_fs_info = sbi; 1194 1195 sb->s_flags |= MS_NODIRATIME; 1196 sb->s_magic = MSDOS_SUPER_MAGIC; 1197 sb->s_op = &fat_sops; 1198 sb->s_export_op = &fat_export_ops; 1199 sbi->dir_ops = fs_dir_inode_ops; 1200 1201 error = parse_options(data, isvfat, silent, &debug, &sbi->options); 1202 if (error) 1203 goto out_fail; 1204 1205 error = -EIO; 1206 sb_min_blocksize(sb, 512); 1207 bh = sb_bread(sb, 0); 1208 if (bh == NULL) { 1209 printk(KERN_ERR "FAT: unable to read boot sector\n"); 1210 goto out_fail; 1211 } 1212 1213 b = (struct fat_boot_sector *) bh->b_data; 1214 if (!b->reserved) { 1215 if (!silent) 1216 printk(KERN_ERR "FAT: bogus number of reserved sectors\n"); 1217 brelse(bh); 1218 goto out_invalid; 1219 } 1220 if (!b->fats) { 1221 if (!silent) 1222 printk(KERN_ERR "FAT: bogus number of FAT structure\n"); 1223 brelse(bh); 1224 goto out_invalid; 1225 } 1226 1227 /* 1228 * Earlier we checked here that b->secs_track and b->head are nonzero, 1229 * but it turns out valid FAT filesystems can have zero there. 1230 */ 1231 1232 media = b->media; 1233 if (!fat_valid_media(media)) { 1234 if (!silent) 1235 printk(KERN_ERR "FAT: invalid media value (0x%02x)\n", 1236 media); 1237 brelse(bh); 1238 goto out_invalid; 1239 } 1240 logical_sector_size = get_unaligned_le16(&b->sector_size); 1241 if (!is_power_of_2(logical_sector_size) 1242 || (logical_sector_size < 512) 1243 || (logical_sector_size > 4096)) { 1244 if (!silent) 1245 printk(KERN_ERR "FAT: bogus logical sector size %u\n", 1246 logical_sector_size); 1247 brelse(bh); 1248 goto out_invalid; 1249 } 1250 sbi->sec_per_clus = b->sec_per_clus; 1251 if (!is_power_of_2(sbi->sec_per_clus)) { 1252 if (!silent) 1253 printk(KERN_ERR "FAT: bogus sectors per cluster %u\n", 1254 sbi->sec_per_clus); 1255 brelse(bh); 1256 goto out_invalid; 1257 } 1258 1259 if (logical_sector_size < sb->s_blocksize) { 1260 printk(KERN_ERR "FAT: logical sector size too small for device" 1261 " (logical sector size = %u)\n", logical_sector_size); 1262 brelse(bh); 1263 goto out_fail; 1264 } 1265 if (logical_sector_size > sb->s_blocksize) { 1266 brelse(bh); 1267 1268 if (!sb_set_blocksize(sb, logical_sector_size)) { 1269 printk(KERN_ERR "FAT: unable to set blocksize %u\n", 1270 logical_sector_size); 1271 goto out_fail; 1272 } 1273 bh = sb_bread(sb, 0); 1274 if (bh == NULL) { 1275 printk(KERN_ERR "FAT: unable to read boot sector" 1276 " (logical sector size = %lu)\n", 1277 sb->s_blocksize); 1278 goto out_fail; 1279 } 1280 b = (struct fat_boot_sector *) bh->b_data; 1281 } 1282 1283 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus; 1284 sbi->cluster_bits = ffs(sbi->cluster_size) - 1; 1285 sbi->fats = b->fats; 1286 sbi->fat_bits = 0; /* Don't know yet */ 1287 sbi->fat_start = le16_to_cpu(b->reserved); 1288 sbi->fat_length = le16_to_cpu(b->fat_length); 1289 sbi->root_cluster = 0; 1290 sbi->free_clusters = -1; /* Don't know yet */ 1291 sbi->free_clus_valid = 0; 1292 sbi->prev_free = FAT_START_ENT; 1293 1294 if (!sbi->fat_length && b->fat32_length) { 1295 struct fat_boot_fsinfo *fsinfo; 1296 struct buffer_head *fsinfo_bh; 1297 1298 /* Must be FAT32 */ 1299 sbi->fat_bits = 32; 1300 sbi->fat_length = le32_to_cpu(b->fat32_length); 1301 sbi->root_cluster = le32_to_cpu(b->root_cluster); 1302 1303 sb->s_maxbytes = 0xffffffff; 1304 1305 /* MC - if info_sector is 0, don't multiply by 0 */ 1306 sbi->fsinfo_sector = le16_to_cpu(b->info_sector); 1307 if (sbi->fsinfo_sector == 0) 1308 sbi->fsinfo_sector = 1; 1309 1310 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector); 1311 if (fsinfo_bh == NULL) { 1312 printk(KERN_ERR "FAT: bread failed, FSINFO block" 1313 " (sector = %lu)\n", sbi->fsinfo_sector); 1314 brelse(bh); 1315 goto out_fail; 1316 } 1317 1318 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data; 1319 if (!IS_FSINFO(fsinfo)) { 1320 printk(KERN_WARNING "FAT: Invalid FSINFO signature: " 1321 "0x%08x, 0x%08x (sector = %lu)\n", 1322 le32_to_cpu(fsinfo->signature1), 1323 le32_to_cpu(fsinfo->signature2), 1324 sbi->fsinfo_sector); 1325 } else { 1326 if (sbi->options.usefree) 1327 sbi->free_clus_valid = 1; 1328 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters); 1329 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster); 1330 } 1331 1332 brelse(fsinfo_bh); 1333 } 1334 1335 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry); 1336 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1; 1337 1338 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length; 1339 sbi->dir_entries = get_unaligned_le16(&b->dir_entries); 1340 if (sbi->dir_entries & (sbi->dir_per_block - 1)) { 1341 if (!silent) 1342 printk(KERN_ERR "FAT: bogus directroy-entries per block" 1343 " (%u)\n", sbi->dir_entries); 1344 brelse(bh); 1345 goto out_invalid; 1346 } 1347 1348 rootdir_sectors = sbi->dir_entries 1349 * sizeof(struct msdos_dir_entry) / sb->s_blocksize; 1350 sbi->data_start = sbi->dir_start + rootdir_sectors; 1351 total_sectors = get_unaligned_le16(&b->sectors); 1352 if (total_sectors == 0) 1353 total_sectors = le32_to_cpu(b->total_sect); 1354 1355 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus; 1356 1357 if (sbi->fat_bits != 32) 1358 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12; 1359 1360 /* check that FAT table does not overflow */ 1361 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits; 1362 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT); 1363 if (total_clusters > MAX_FAT(sb)) { 1364 if (!silent) 1365 printk(KERN_ERR "FAT: count of clusters too big (%u)\n", 1366 total_clusters); 1367 brelse(bh); 1368 goto out_invalid; 1369 } 1370 1371 sbi->max_cluster = total_clusters + FAT_START_ENT; 1372 /* check the free_clusters, it's not necessarily correct */ 1373 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters) 1374 sbi->free_clusters = -1; 1375 /* check the prev_free, it's not necessarily correct */ 1376 sbi->prev_free %= sbi->max_cluster; 1377 if (sbi->prev_free < FAT_START_ENT) 1378 sbi->prev_free = FAT_START_ENT; 1379 1380 brelse(bh); 1381 1382 /* set up enough so that it can read an inode */ 1383 fat_hash_init(sb); 1384 fat_ent_access_init(sb); 1385 1386 /* 1387 * The low byte of FAT's first entry must have same value with 1388 * media-field. But in real world, too many devices is 1389 * writing wrong value. So, removed that validity check. 1390 * 1391 * if (FAT_FIRST_ENT(sb, media) != first) 1392 */ 1393 1394 error = -EINVAL; 1395 sprintf(buf, "cp%d", sbi->options.codepage); 1396 sbi->nls_disk = load_nls(buf); 1397 if (!sbi->nls_disk) { 1398 printk(KERN_ERR "FAT: codepage %s not found\n", buf); 1399 goto out_fail; 1400 } 1401 1402 /* FIXME: utf8 is using iocharset for upper/lower conversion */ 1403 if (sbi->options.isvfat) { 1404 sbi->nls_io = load_nls(sbi->options.iocharset); 1405 if (!sbi->nls_io) { 1406 printk(KERN_ERR "FAT: IO charset %s not found\n", 1407 sbi->options.iocharset); 1408 goto out_fail; 1409 } 1410 } 1411 1412 error = -ENOMEM; 1413 root_inode = new_inode(sb); 1414 if (!root_inode) 1415 goto out_fail; 1416 root_inode->i_ino = MSDOS_ROOT_INO; 1417 root_inode->i_version = 1; 1418 error = fat_read_root(root_inode); 1419 if (error < 0) 1420 goto out_fail; 1421 error = -ENOMEM; 1422 insert_inode_hash(root_inode); 1423 sb->s_root = d_alloc_root(root_inode); 1424 if (!sb->s_root) { 1425 printk(KERN_ERR "FAT: get root inode failed\n"); 1426 goto out_fail; 1427 } 1428 1429 return 0; 1430 1431 out_invalid: 1432 error = -EINVAL; 1433 if (!silent) 1434 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem" 1435 " on dev %s.\n", sb->s_id); 1436 1437 out_fail: 1438 if (root_inode) 1439 iput(root_inode); 1440 if (sbi->nls_io) 1441 unload_nls(sbi->nls_io); 1442 if (sbi->nls_disk) 1443 unload_nls(sbi->nls_disk); 1444 if (sbi->options.iocharset != fat_default_iocharset) 1445 kfree(sbi->options.iocharset); 1446 sb->s_fs_info = NULL; 1447 kfree(sbi); 1448 return error; 1449 } 1450 1451 EXPORT_SYMBOL_GPL(fat_fill_super); 1452 1453 /* 1454 * helper function for fat_flush_inodes. This writes both the inode 1455 * and the file data blocks, waiting for in flight data blocks before 1456 * the start of the call. It does not wait for any io started 1457 * during the call 1458 */ 1459 static int writeback_inode(struct inode *inode) 1460 { 1461 1462 int ret; 1463 struct address_space *mapping = inode->i_mapping; 1464 struct writeback_control wbc = { 1465 .sync_mode = WB_SYNC_NONE, 1466 .nr_to_write = 0, 1467 }; 1468 /* if we used WB_SYNC_ALL, sync_inode waits for the io for the 1469 * inode to finish. So WB_SYNC_NONE is sent down to sync_inode 1470 * and filemap_fdatawrite is used for the data blocks 1471 */ 1472 ret = sync_inode(inode, &wbc); 1473 if (!ret) 1474 ret = filemap_fdatawrite(mapping); 1475 return ret; 1476 } 1477 1478 /* 1479 * write data and metadata corresponding to i1 and i2. The io is 1480 * started but we do not wait for any of it to finish. 1481 * 1482 * filemap_flush is used for the block device, so if there is a dirty 1483 * page for a block already in flight, we will not wait and start the 1484 * io over again 1485 */ 1486 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2) 1487 { 1488 int ret = 0; 1489 if (!MSDOS_SB(sb)->options.flush) 1490 return 0; 1491 if (i1) 1492 ret = writeback_inode(i1); 1493 if (!ret && i2) 1494 ret = writeback_inode(i2); 1495 if (!ret) { 1496 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping; 1497 ret = filemap_flush(mapping); 1498 } 1499 return ret; 1500 } 1501 EXPORT_SYMBOL_GPL(fat_flush_inodes); 1502 1503 static int __init init_fat_fs(void) 1504 { 1505 int err; 1506 1507 err = fat_cache_init(); 1508 if (err) 1509 return err; 1510 1511 err = fat_init_inodecache(); 1512 if (err) 1513 goto failed; 1514 1515 return 0; 1516 1517 failed: 1518 fat_cache_destroy(); 1519 return err; 1520 } 1521 1522 static void __exit exit_fat_fs(void) 1523 { 1524 fat_cache_destroy(); 1525 fat_destroy_inodecache(); 1526 } 1527 1528 module_init(init_fat_fs) 1529 module_exit(exit_fat_fs) 1530 1531 MODULE_LICENSE("GPL"); 1532