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/seq_file.h> 18 #include <linux/pagemap.h> 19 #include <linux/mpage.h> 20 #include <linux/buffer_head.h> 21 #include <linux/exportfs.h> 22 #include <linux/mount.h> 23 #include <linux/vfs.h> 24 #include <linux/parser.h> 25 #include <linux/uio.h> 26 #include <linux/writeback.h> 27 #include <linux/log2.h> 28 #include <linux/hash.h> 29 #include <asm/unaligned.h> 30 #include "fat.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, create); 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_error(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, create); 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 void fat_write_failed(struct address_space *mapping, loff_t to) 145 { 146 struct inode *inode = mapping->host; 147 148 if (to > inode->i_size) { 149 truncate_pagecache(inode, to, inode->i_size); 150 fat_truncate_blocks(inode, inode->i_size); 151 } 152 } 153 154 static int fat_write_begin(struct file *file, struct address_space *mapping, 155 loff_t pos, unsigned len, unsigned flags, 156 struct page **pagep, void **fsdata) 157 { 158 int err; 159 160 *pagep = NULL; 161 err = cont_write_begin(file, mapping, pos, len, flags, 162 pagep, fsdata, fat_get_block, 163 &MSDOS_I(mapping->host)->mmu_private); 164 if (err < 0) 165 fat_write_failed(mapping, pos + len); 166 return err; 167 } 168 169 static int fat_write_end(struct file *file, struct address_space *mapping, 170 loff_t pos, unsigned len, unsigned copied, 171 struct page *pagep, void *fsdata) 172 { 173 struct inode *inode = mapping->host; 174 int err; 175 err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata); 176 if (err < len) 177 fat_write_failed(mapping, pos + len); 178 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) { 179 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC; 180 MSDOS_I(inode)->i_attrs |= ATTR_ARCH; 181 mark_inode_dirty(inode); 182 } 183 return err; 184 } 185 186 static ssize_t fat_direct_IO(int rw, struct kiocb *iocb, 187 const struct iovec *iov, 188 loff_t offset, unsigned long nr_segs) 189 { 190 struct file *file = iocb->ki_filp; 191 struct address_space *mapping = file->f_mapping; 192 struct inode *inode = mapping->host; 193 ssize_t ret; 194 195 if (rw == WRITE) { 196 /* 197 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(), 198 * so we need to update the ->mmu_private to block boundary. 199 * 200 * But we must fill the remaining area or hole by nul for 201 * updating ->mmu_private. 202 * 203 * Return 0, and fallback to normal buffered write. 204 */ 205 loff_t size = offset + iov_length(iov, nr_segs); 206 if (MSDOS_I(inode)->mmu_private < size) 207 return 0; 208 } 209 210 /* 211 * FAT need to use the DIO_LOCKING for avoiding the race 212 * condition of fat_get_block() and ->truncate(). 213 */ 214 ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, 215 iov, offset, nr_segs, fat_get_block, NULL); 216 if (ret < 0 && (rw & WRITE)) 217 fat_write_failed(mapping, offset + iov_length(iov, nr_segs)); 218 219 return ret; 220 } 221 222 static sector_t _fat_bmap(struct address_space *mapping, sector_t block) 223 { 224 sector_t blocknr; 225 226 /* fat_get_cluster() assumes the requested blocknr isn't truncated. */ 227 down_read(&mapping->host->i_alloc_sem); 228 blocknr = generic_block_bmap(mapping, block, fat_get_block); 229 up_read(&mapping->host->i_alloc_sem); 230 231 return blocknr; 232 } 233 234 static const struct address_space_operations fat_aops = { 235 .readpage = fat_readpage, 236 .readpages = fat_readpages, 237 .writepage = fat_writepage, 238 .writepages = fat_writepages, 239 .write_begin = fat_write_begin, 240 .write_end = fat_write_end, 241 .direct_IO = fat_direct_IO, 242 .bmap = _fat_bmap 243 }; 244 245 /* 246 * New FAT inode stuff. We do the following: 247 * a) i_ino is constant and has nothing with on-disk location. 248 * b) FAT manages its own cache of directory entries. 249 * c) *This* cache is indexed by on-disk location. 250 * d) inode has an associated directory entry, all right, but 251 * it may be unhashed. 252 * e) currently entries are stored within struct inode. That should 253 * change. 254 * f) we deal with races in the following way: 255 * 1. readdir() and lookup() do FAT-dir-cache lookup. 256 * 2. rename() unhashes the F-d-c entry and rehashes it in 257 * a new place. 258 * 3. unlink() and rmdir() unhash F-d-c entry. 259 * 4. fat_write_inode() checks whether the thing is unhashed. 260 * If it is we silently return. If it isn't we do bread(), 261 * check if the location is still valid and retry if it 262 * isn't. Otherwise we do changes. 263 * 5. Spinlock is used to protect hash/unhash/location check/lookup 264 * 6. fat_evict_inode() unhashes the F-d-c entry. 265 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry 266 * and consider negative result as cache miss. 267 */ 268 269 static void fat_hash_init(struct super_block *sb) 270 { 271 struct msdos_sb_info *sbi = MSDOS_SB(sb); 272 int i; 273 274 spin_lock_init(&sbi->inode_hash_lock); 275 for (i = 0; i < FAT_HASH_SIZE; i++) 276 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]); 277 } 278 279 static inline unsigned long fat_hash(loff_t i_pos) 280 { 281 return hash_32(i_pos, FAT_HASH_BITS); 282 } 283 284 void fat_attach(struct inode *inode, loff_t i_pos) 285 { 286 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 287 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos); 288 289 spin_lock(&sbi->inode_hash_lock); 290 MSDOS_I(inode)->i_pos = i_pos; 291 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head); 292 spin_unlock(&sbi->inode_hash_lock); 293 } 294 EXPORT_SYMBOL_GPL(fat_attach); 295 296 void fat_detach(struct inode *inode) 297 { 298 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 299 spin_lock(&sbi->inode_hash_lock); 300 MSDOS_I(inode)->i_pos = 0; 301 hlist_del_init(&MSDOS_I(inode)->i_fat_hash); 302 spin_unlock(&sbi->inode_hash_lock); 303 } 304 EXPORT_SYMBOL_GPL(fat_detach); 305 306 struct inode *fat_iget(struct super_block *sb, loff_t i_pos) 307 { 308 struct msdos_sb_info *sbi = MSDOS_SB(sb); 309 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos); 310 struct hlist_node *_p; 311 struct msdos_inode_info *i; 312 struct inode *inode = NULL; 313 314 spin_lock(&sbi->inode_hash_lock); 315 hlist_for_each_entry(i, _p, head, i_fat_hash) { 316 BUG_ON(i->vfs_inode.i_sb != sb); 317 if (i->i_pos != i_pos) 318 continue; 319 inode = igrab(&i->vfs_inode); 320 if (inode) 321 break; 322 } 323 spin_unlock(&sbi->inode_hash_lock); 324 return inode; 325 } 326 327 static int is_exec(unsigned char *extension) 328 { 329 unsigned char *exe_extensions = "EXECOMBAT", *walk; 330 331 for (walk = exe_extensions; *walk; walk += 3) 332 if (!strncmp(extension, walk, 3)) 333 return 1; 334 return 0; 335 } 336 337 static int fat_calc_dir_size(struct inode *inode) 338 { 339 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 340 int ret, fclus, dclus; 341 342 inode->i_size = 0; 343 if (MSDOS_I(inode)->i_start == 0) 344 return 0; 345 346 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); 347 if (ret < 0) 348 return ret; 349 inode->i_size = (fclus + 1) << sbi->cluster_bits; 350 351 return 0; 352 } 353 354 /* doesn't deal with root inode */ 355 static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de) 356 { 357 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 358 int error; 359 360 MSDOS_I(inode)->i_pos = 0; 361 inode->i_uid = sbi->options.fs_uid; 362 inode->i_gid = sbi->options.fs_gid; 363 inode->i_version++; 364 inode->i_generation = get_seconds(); 365 366 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) { 367 inode->i_generation &= ~1; 368 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO); 369 inode->i_op = sbi->dir_ops; 370 inode->i_fop = &fat_dir_operations; 371 372 MSDOS_I(inode)->i_start = le16_to_cpu(de->start); 373 if (sbi->fat_bits == 32) 374 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16); 375 376 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 377 error = fat_calc_dir_size(inode); 378 if (error < 0) 379 return error; 380 MSDOS_I(inode)->mmu_private = inode->i_size; 381 382 inode->i_nlink = fat_subdirs(inode); 383 } else { /* not a directory */ 384 inode->i_generation |= 1; 385 inode->i_mode = fat_make_mode(sbi, de->attr, 386 ((sbi->options.showexec && !is_exec(de->name + 8)) 387 ? S_IRUGO|S_IWUGO : S_IRWXUGO)); 388 MSDOS_I(inode)->i_start = le16_to_cpu(de->start); 389 if (sbi->fat_bits == 32) 390 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16); 391 392 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 393 inode->i_size = le32_to_cpu(de->size); 394 inode->i_op = &fat_file_inode_operations; 395 inode->i_fop = &fat_file_operations; 396 inode->i_mapping->a_ops = &fat_aops; 397 MSDOS_I(inode)->mmu_private = inode->i_size; 398 } 399 if (de->attr & ATTR_SYS) { 400 if (sbi->options.sys_immutable) 401 inode->i_flags |= S_IMMUTABLE; 402 } 403 fat_save_attrs(inode, de->attr); 404 405 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 406 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 407 408 fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0); 409 if (sbi->options.isvfat) { 410 fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime, 411 de->cdate, de->ctime_cs); 412 fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0); 413 } else 414 inode->i_ctime = inode->i_atime = inode->i_mtime; 415 416 return 0; 417 } 418 419 struct inode *fat_build_inode(struct super_block *sb, 420 struct msdos_dir_entry *de, loff_t i_pos) 421 { 422 struct inode *inode; 423 int err; 424 425 inode = fat_iget(sb, i_pos); 426 if (inode) 427 goto out; 428 inode = new_inode(sb); 429 if (!inode) { 430 inode = ERR_PTR(-ENOMEM); 431 goto out; 432 } 433 inode->i_ino = iunique(sb, MSDOS_ROOT_INO); 434 inode->i_version = 1; 435 err = fat_fill_inode(inode, de); 436 if (err) { 437 iput(inode); 438 inode = ERR_PTR(err); 439 goto out; 440 } 441 fat_attach(inode, i_pos); 442 insert_inode_hash(inode); 443 out: 444 return inode; 445 } 446 447 EXPORT_SYMBOL_GPL(fat_build_inode); 448 449 static void fat_evict_inode(struct inode *inode) 450 { 451 truncate_inode_pages(&inode->i_data, 0); 452 if (!inode->i_nlink) { 453 inode->i_size = 0; 454 fat_truncate_blocks(inode, 0); 455 } 456 invalidate_inode_buffers(inode); 457 end_writeback(inode); 458 fat_cache_inval_inode(inode); 459 fat_detach(inode); 460 } 461 462 static void fat_write_super(struct super_block *sb) 463 { 464 lock_super(sb); 465 sb->s_dirt = 0; 466 467 if (!(sb->s_flags & MS_RDONLY)) 468 fat_clusters_flush(sb); 469 unlock_super(sb); 470 } 471 472 static int fat_sync_fs(struct super_block *sb, int wait) 473 { 474 int err = 0; 475 476 if (sb->s_dirt) { 477 lock_super(sb); 478 sb->s_dirt = 0; 479 err = fat_clusters_flush(sb); 480 unlock_super(sb); 481 } 482 483 return err; 484 } 485 486 static void fat_put_super(struct super_block *sb) 487 { 488 struct msdos_sb_info *sbi = MSDOS_SB(sb); 489 490 if (sb->s_dirt) 491 fat_write_super(sb); 492 493 iput(sbi->fat_inode); 494 495 unload_nls(sbi->nls_disk); 496 unload_nls(sbi->nls_io); 497 498 if (sbi->options.iocharset != fat_default_iocharset) 499 kfree(sbi->options.iocharset); 500 501 sb->s_fs_info = NULL; 502 kfree(sbi); 503 } 504 505 static struct kmem_cache *fat_inode_cachep; 506 507 static struct inode *fat_alloc_inode(struct super_block *sb) 508 { 509 struct msdos_inode_info *ei; 510 ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS); 511 if (!ei) 512 return NULL; 513 return &ei->vfs_inode; 514 } 515 516 static void fat_i_callback(struct rcu_head *head) 517 { 518 struct inode *inode = container_of(head, struct inode, i_rcu); 519 INIT_LIST_HEAD(&inode->i_dentry); 520 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode)); 521 } 522 523 static void fat_destroy_inode(struct inode *inode) 524 { 525 call_rcu(&inode->i_rcu, fat_i_callback); 526 } 527 528 static void init_once(void *foo) 529 { 530 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo; 531 532 spin_lock_init(&ei->cache_lru_lock); 533 ei->nr_caches = 0; 534 ei->cache_valid_id = FAT_CACHE_VALID + 1; 535 INIT_LIST_HEAD(&ei->cache_lru); 536 INIT_HLIST_NODE(&ei->i_fat_hash); 537 inode_init_once(&ei->vfs_inode); 538 } 539 540 static int __init fat_init_inodecache(void) 541 { 542 fat_inode_cachep = kmem_cache_create("fat_inode_cache", 543 sizeof(struct msdos_inode_info), 544 0, (SLAB_RECLAIM_ACCOUNT| 545 SLAB_MEM_SPREAD), 546 init_once); 547 if (fat_inode_cachep == NULL) 548 return -ENOMEM; 549 return 0; 550 } 551 552 static void __exit fat_destroy_inodecache(void) 553 { 554 kmem_cache_destroy(fat_inode_cachep); 555 } 556 557 static int fat_remount(struct super_block *sb, int *flags, char *data) 558 { 559 struct msdos_sb_info *sbi = MSDOS_SB(sb); 560 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME); 561 return 0; 562 } 563 564 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf) 565 { 566 struct super_block *sb = dentry->d_sb; 567 struct msdos_sb_info *sbi = MSDOS_SB(sb); 568 u64 id = huge_encode_dev(sb->s_bdev->bd_dev); 569 570 /* If the count of free cluster is still unknown, counts it here. */ 571 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) { 572 int err = fat_count_free_clusters(dentry->d_sb); 573 if (err) 574 return err; 575 } 576 577 buf->f_type = dentry->d_sb->s_magic; 578 buf->f_bsize = sbi->cluster_size; 579 buf->f_blocks = sbi->max_cluster - FAT_START_ENT; 580 buf->f_bfree = sbi->free_clusters; 581 buf->f_bavail = sbi->free_clusters; 582 buf->f_fsid.val[0] = (u32)id; 583 buf->f_fsid.val[1] = (u32)(id >> 32); 584 buf->f_namelen = 585 (sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE; 586 587 return 0; 588 } 589 590 static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi, 591 struct inode *inode) 592 { 593 loff_t i_pos; 594 #if BITS_PER_LONG == 32 595 spin_lock(&sbi->inode_hash_lock); 596 #endif 597 i_pos = MSDOS_I(inode)->i_pos; 598 #if BITS_PER_LONG == 32 599 spin_unlock(&sbi->inode_hash_lock); 600 #endif 601 return i_pos; 602 } 603 604 static int __fat_write_inode(struct inode *inode, int wait) 605 { 606 struct super_block *sb = inode->i_sb; 607 struct msdos_sb_info *sbi = MSDOS_SB(sb); 608 struct buffer_head *bh; 609 struct msdos_dir_entry *raw_entry; 610 loff_t i_pos; 611 int err; 612 613 if (inode->i_ino == MSDOS_ROOT_INO) 614 return 0; 615 616 retry: 617 i_pos = fat_i_pos_read(sbi, inode); 618 if (!i_pos) 619 return 0; 620 621 bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits); 622 if (!bh) { 623 fat_msg(sb, KERN_ERR, "unable to read inode block " 624 "for updating (i_pos %lld)", i_pos); 625 return -EIO; 626 } 627 spin_lock(&sbi->inode_hash_lock); 628 if (i_pos != MSDOS_I(inode)->i_pos) { 629 spin_unlock(&sbi->inode_hash_lock); 630 brelse(bh); 631 goto retry; 632 } 633 634 raw_entry = &((struct msdos_dir_entry *) (bh->b_data)) 635 [i_pos & (sbi->dir_per_block - 1)]; 636 if (S_ISDIR(inode->i_mode)) 637 raw_entry->size = 0; 638 else 639 raw_entry->size = cpu_to_le32(inode->i_size); 640 raw_entry->attr = fat_make_attrs(inode); 641 raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart); 642 raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16); 643 fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time, 644 &raw_entry->date, NULL); 645 if (sbi->options.isvfat) { 646 __le16 atime; 647 fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime, 648 &raw_entry->cdate, &raw_entry->ctime_cs); 649 fat_time_unix2fat(sbi, &inode->i_atime, &atime, 650 &raw_entry->adate, NULL); 651 } 652 spin_unlock(&sbi->inode_hash_lock); 653 mark_buffer_dirty(bh); 654 err = 0; 655 if (wait) 656 err = sync_dirty_buffer(bh); 657 brelse(bh); 658 return err; 659 } 660 661 static int fat_write_inode(struct inode *inode, struct writeback_control *wbc) 662 { 663 return __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL); 664 } 665 666 int fat_sync_inode(struct inode *inode) 667 { 668 return __fat_write_inode(inode, 1); 669 } 670 671 EXPORT_SYMBOL_GPL(fat_sync_inode); 672 673 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt); 674 static const struct super_operations fat_sops = { 675 .alloc_inode = fat_alloc_inode, 676 .destroy_inode = fat_destroy_inode, 677 .write_inode = fat_write_inode, 678 .evict_inode = fat_evict_inode, 679 .put_super = fat_put_super, 680 .write_super = fat_write_super, 681 .sync_fs = fat_sync_fs, 682 .statfs = fat_statfs, 683 .remount_fs = fat_remount, 684 685 .show_options = fat_show_options, 686 }; 687 688 /* 689 * a FAT file handle with fhtype 3 is 690 * 0/ i_ino - for fast, reliable lookup if still in the cache 691 * 1/ i_generation - to see if i_ino is still valid 692 * bit 0 == 0 iff directory 693 * 2/ i_pos(8-39) - if ino has changed, but still in cache 694 * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos 695 * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc 696 * 697 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum 698 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits 699 * of i_logstart is used to store the directory entry offset. 700 */ 701 702 static struct dentry *fat_fh_to_dentry(struct super_block *sb, 703 struct fid *fid, int fh_len, int fh_type) 704 { 705 struct inode *inode = NULL; 706 u32 *fh = fid->raw; 707 708 if (fh_len < 5 || fh_type != 3) 709 return NULL; 710 711 inode = ilookup(sb, fh[0]); 712 if (!inode || inode->i_generation != fh[1]) { 713 if (inode) 714 iput(inode); 715 inode = NULL; 716 } 717 if (!inode) { 718 loff_t i_pos; 719 int i_logstart = fh[3] & 0x0fffffff; 720 721 i_pos = (loff_t)fh[2] << 8; 722 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28); 723 724 /* try 2 - see if i_pos is in F-d-c 725 * require i_logstart to be the same 726 * Will fail if you truncate and then re-write 727 */ 728 729 inode = fat_iget(sb, i_pos); 730 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) { 731 iput(inode); 732 inode = NULL; 733 } 734 } 735 736 /* 737 * For now, do nothing if the inode is not found. 738 * 739 * What we could do is: 740 * 741 * - follow the file starting at fh[4], and record the ".." entry, 742 * and the name of the fh[2] entry. 743 * - then follow the ".." file finding the next step up. 744 * 745 * This way we build a path to the root of the tree. If this works, we 746 * lookup the path and so get this inode into the cache. Finally try 747 * the fat_iget lookup again. If that fails, then we are totally out 748 * of luck. But all that is for another day 749 */ 750 return d_obtain_alias(inode); 751 } 752 753 static int 754 fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable) 755 { 756 int len = *lenp; 757 struct inode *inode = de->d_inode; 758 u32 ipos_h, ipos_m, ipos_l; 759 760 if (len < 5) { 761 *lenp = 5; 762 return 255; /* no room */ 763 } 764 765 ipos_h = MSDOS_I(inode)->i_pos >> 8; 766 ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24; 767 ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28; 768 *lenp = 5; 769 fh[0] = inode->i_ino; 770 fh[1] = inode->i_generation; 771 fh[2] = ipos_h; 772 fh[3] = ipos_m | MSDOS_I(inode)->i_logstart; 773 spin_lock(&de->d_lock); 774 fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart; 775 spin_unlock(&de->d_lock); 776 return 3; 777 } 778 779 static struct dentry *fat_get_parent(struct dentry *child) 780 { 781 struct super_block *sb = child->d_sb; 782 struct buffer_head *bh; 783 struct msdos_dir_entry *de; 784 loff_t i_pos; 785 struct dentry *parent; 786 struct inode *inode; 787 int err; 788 789 lock_super(sb); 790 791 err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos); 792 if (err) { 793 parent = ERR_PTR(err); 794 goto out; 795 } 796 inode = fat_build_inode(sb, de, i_pos); 797 brelse(bh); 798 799 parent = d_obtain_alias(inode); 800 out: 801 unlock_super(sb); 802 803 return parent; 804 } 805 806 static const struct export_operations fat_export_ops = { 807 .encode_fh = fat_encode_fh, 808 .fh_to_dentry = fat_fh_to_dentry, 809 .get_parent = fat_get_parent, 810 }; 811 812 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt) 813 { 814 struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb); 815 struct fat_mount_options *opts = &sbi->options; 816 int isvfat = opts->isvfat; 817 818 if (opts->fs_uid != 0) 819 seq_printf(m, ",uid=%u", opts->fs_uid); 820 if (opts->fs_gid != 0) 821 seq_printf(m, ",gid=%u", opts->fs_gid); 822 seq_printf(m, ",fmask=%04o", opts->fs_fmask); 823 seq_printf(m, ",dmask=%04o", opts->fs_dmask); 824 if (opts->allow_utime) 825 seq_printf(m, ",allow_utime=%04o", opts->allow_utime); 826 if (sbi->nls_disk) 827 seq_printf(m, ",codepage=%s", sbi->nls_disk->charset); 828 if (isvfat) { 829 if (sbi->nls_io) 830 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset); 831 832 switch (opts->shortname) { 833 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95: 834 seq_puts(m, ",shortname=win95"); 835 break; 836 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT: 837 seq_puts(m, ",shortname=winnt"); 838 break; 839 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95: 840 seq_puts(m, ",shortname=mixed"); 841 break; 842 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95: 843 seq_puts(m, ",shortname=lower"); 844 break; 845 default: 846 seq_puts(m, ",shortname=unknown"); 847 break; 848 } 849 } 850 if (opts->name_check != 'n') 851 seq_printf(m, ",check=%c", opts->name_check); 852 if (opts->usefree) 853 seq_puts(m, ",usefree"); 854 if (opts->quiet) 855 seq_puts(m, ",quiet"); 856 if (opts->showexec) 857 seq_puts(m, ",showexec"); 858 if (opts->sys_immutable) 859 seq_puts(m, ",sys_immutable"); 860 if (!isvfat) { 861 if (opts->dotsOK) 862 seq_puts(m, ",dotsOK=yes"); 863 if (opts->nocase) 864 seq_puts(m, ",nocase"); 865 } else { 866 if (opts->utf8) 867 seq_puts(m, ",utf8"); 868 if (opts->unicode_xlate) 869 seq_puts(m, ",uni_xlate"); 870 if (!opts->numtail) 871 seq_puts(m, ",nonumtail"); 872 if (opts->rodir) 873 seq_puts(m, ",rodir"); 874 } 875 if (opts->flush) 876 seq_puts(m, ",flush"); 877 if (opts->tz_utc) 878 seq_puts(m, ",tz=UTC"); 879 if (opts->errors == FAT_ERRORS_CONT) 880 seq_puts(m, ",errors=continue"); 881 else if (opts->errors == FAT_ERRORS_PANIC) 882 seq_puts(m, ",errors=panic"); 883 else 884 seq_puts(m, ",errors=remount-ro"); 885 if (opts->discard) 886 seq_puts(m, ",discard"); 887 888 return 0; 889 } 890 891 enum { 892 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid, 893 Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage, 894 Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug, 895 Opt_immutable, Opt_dots, Opt_nodots, 896 Opt_charset, Opt_shortname_lower, Opt_shortname_win95, 897 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes, 898 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes, 899 Opt_obsolate, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont, 900 Opt_err_panic, Opt_err_ro, Opt_discard, Opt_err, 901 }; 902 903 static const match_table_t fat_tokens = { 904 {Opt_check_r, "check=relaxed"}, 905 {Opt_check_s, "check=strict"}, 906 {Opt_check_n, "check=normal"}, 907 {Opt_check_r, "check=r"}, 908 {Opt_check_s, "check=s"}, 909 {Opt_check_n, "check=n"}, 910 {Opt_uid, "uid=%u"}, 911 {Opt_gid, "gid=%u"}, 912 {Opt_umask, "umask=%o"}, 913 {Opt_dmask, "dmask=%o"}, 914 {Opt_fmask, "fmask=%o"}, 915 {Opt_allow_utime, "allow_utime=%o"}, 916 {Opt_codepage, "codepage=%u"}, 917 {Opt_usefree, "usefree"}, 918 {Opt_nocase, "nocase"}, 919 {Opt_quiet, "quiet"}, 920 {Opt_showexec, "showexec"}, 921 {Opt_debug, "debug"}, 922 {Opt_immutable, "sys_immutable"}, 923 {Opt_flush, "flush"}, 924 {Opt_tz_utc, "tz=UTC"}, 925 {Opt_err_cont, "errors=continue"}, 926 {Opt_err_panic, "errors=panic"}, 927 {Opt_err_ro, "errors=remount-ro"}, 928 {Opt_discard, "discard"}, 929 {Opt_obsolate, "conv=binary"}, 930 {Opt_obsolate, "conv=text"}, 931 {Opt_obsolate, "conv=auto"}, 932 {Opt_obsolate, "conv=b"}, 933 {Opt_obsolate, "conv=t"}, 934 {Opt_obsolate, "conv=a"}, 935 {Opt_obsolate, "fat=%u"}, 936 {Opt_obsolate, "blocksize=%u"}, 937 {Opt_obsolate, "cvf_format=%20s"}, 938 {Opt_obsolate, "cvf_options=%100s"}, 939 {Opt_obsolate, "posix"}, 940 {Opt_err, NULL}, 941 }; 942 static const match_table_t msdos_tokens = { 943 {Opt_nodots, "nodots"}, 944 {Opt_nodots, "dotsOK=no"}, 945 {Opt_dots, "dots"}, 946 {Opt_dots, "dotsOK=yes"}, 947 {Opt_err, NULL} 948 }; 949 static const match_table_t vfat_tokens = { 950 {Opt_charset, "iocharset=%s"}, 951 {Opt_shortname_lower, "shortname=lower"}, 952 {Opt_shortname_win95, "shortname=win95"}, 953 {Opt_shortname_winnt, "shortname=winnt"}, 954 {Opt_shortname_mixed, "shortname=mixed"}, 955 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */ 956 {Opt_utf8_no, "utf8=no"}, 957 {Opt_utf8_no, "utf8=false"}, 958 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */ 959 {Opt_utf8_yes, "utf8=yes"}, 960 {Opt_utf8_yes, "utf8=true"}, 961 {Opt_utf8_yes, "utf8"}, 962 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */ 963 {Opt_uni_xl_no, "uni_xlate=no"}, 964 {Opt_uni_xl_no, "uni_xlate=false"}, 965 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */ 966 {Opt_uni_xl_yes, "uni_xlate=yes"}, 967 {Opt_uni_xl_yes, "uni_xlate=true"}, 968 {Opt_uni_xl_yes, "uni_xlate"}, 969 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */ 970 {Opt_nonumtail_no, "nonumtail=no"}, 971 {Opt_nonumtail_no, "nonumtail=false"}, 972 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */ 973 {Opt_nonumtail_yes, "nonumtail=yes"}, 974 {Opt_nonumtail_yes, "nonumtail=true"}, 975 {Opt_nonumtail_yes, "nonumtail"}, 976 {Opt_rodir, "rodir"}, 977 {Opt_err, NULL} 978 }; 979 980 static int parse_options(struct super_block *sb, char *options, int is_vfat, 981 int silent, int *debug, struct fat_mount_options *opts) 982 { 983 char *p; 984 substring_t args[MAX_OPT_ARGS]; 985 int option; 986 char *iocharset; 987 988 opts->isvfat = is_vfat; 989 990 opts->fs_uid = current_uid(); 991 opts->fs_gid = current_gid(); 992 opts->fs_fmask = opts->fs_dmask = current_umask(); 993 opts->allow_utime = -1; 994 opts->codepage = fat_default_codepage; 995 opts->iocharset = fat_default_iocharset; 996 if (is_vfat) { 997 opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95; 998 opts->rodir = 0; 999 } else { 1000 opts->shortname = 0; 1001 opts->rodir = 1; 1002 } 1003 opts->name_check = 'n'; 1004 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0; 1005 opts->utf8 = opts->unicode_xlate = 0; 1006 opts->numtail = 1; 1007 opts->usefree = opts->nocase = 0; 1008 opts->tz_utc = 0; 1009 opts->errors = FAT_ERRORS_RO; 1010 *debug = 0; 1011 1012 if (!options) 1013 goto out; 1014 1015 while ((p = strsep(&options, ",")) != NULL) { 1016 int token; 1017 if (!*p) 1018 continue; 1019 1020 token = match_token(p, fat_tokens, args); 1021 if (token == Opt_err) { 1022 if (is_vfat) 1023 token = match_token(p, vfat_tokens, args); 1024 else 1025 token = match_token(p, msdos_tokens, args); 1026 } 1027 switch (token) { 1028 case Opt_check_s: 1029 opts->name_check = 's'; 1030 break; 1031 case Opt_check_r: 1032 opts->name_check = 'r'; 1033 break; 1034 case Opt_check_n: 1035 opts->name_check = 'n'; 1036 break; 1037 case Opt_usefree: 1038 opts->usefree = 1; 1039 break; 1040 case Opt_nocase: 1041 if (!is_vfat) 1042 opts->nocase = 1; 1043 else { 1044 /* for backward compatibility */ 1045 opts->shortname = VFAT_SFN_DISPLAY_WIN95 1046 | VFAT_SFN_CREATE_WIN95; 1047 } 1048 break; 1049 case Opt_quiet: 1050 opts->quiet = 1; 1051 break; 1052 case Opt_showexec: 1053 opts->showexec = 1; 1054 break; 1055 case Opt_debug: 1056 *debug = 1; 1057 break; 1058 case Opt_immutable: 1059 opts->sys_immutable = 1; 1060 break; 1061 case Opt_uid: 1062 if (match_int(&args[0], &option)) 1063 return 0; 1064 opts->fs_uid = option; 1065 break; 1066 case Opt_gid: 1067 if (match_int(&args[0], &option)) 1068 return 0; 1069 opts->fs_gid = option; 1070 break; 1071 case Opt_umask: 1072 if (match_octal(&args[0], &option)) 1073 return 0; 1074 opts->fs_fmask = opts->fs_dmask = option; 1075 break; 1076 case Opt_dmask: 1077 if (match_octal(&args[0], &option)) 1078 return 0; 1079 opts->fs_dmask = option; 1080 break; 1081 case Opt_fmask: 1082 if (match_octal(&args[0], &option)) 1083 return 0; 1084 opts->fs_fmask = option; 1085 break; 1086 case Opt_allow_utime: 1087 if (match_octal(&args[0], &option)) 1088 return 0; 1089 opts->allow_utime = option & (S_IWGRP | S_IWOTH); 1090 break; 1091 case Opt_codepage: 1092 if (match_int(&args[0], &option)) 1093 return 0; 1094 opts->codepage = option; 1095 break; 1096 case Opt_flush: 1097 opts->flush = 1; 1098 break; 1099 case Opt_tz_utc: 1100 opts->tz_utc = 1; 1101 break; 1102 case Opt_err_cont: 1103 opts->errors = FAT_ERRORS_CONT; 1104 break; 1105 case Opt_err_panic: 1106 opts->errors = FAT_ERRORS_PANIC; 1107 break; 1108 case Opt_err_ro: 1109 opts->errors = FAT_ERRORS_RO; 1110 break; 1111 1112 /* msdos specific */ 1113 case Opt_dots: 1114 opts->dotsOK = 1; 1115 break; 1116 case Opt_nodots: 1117 opts->dotsOK = 0; 1118 break; 1119 1120 /* vfat specific */ 1121 case Opt_charset: 1122 if (opts->iocharset != fat_default_iocharset) 1123 kfree(opts->iocharset); 1124 iocharset = match_strdup(&args[0]); 1125 if (!iocharset) 1126 return -ENOMEM; 1127 opts->iocharset = iocharset; 1128 break; 1129 case Opt_shortname_lower: 1130 opts->shortname = VFAT_SFN_DISPLAY_LOWER 1131 | VFAT_SFN_CREATE_WIN95; 1132 break; 1133 case Opt_shortname_win95: 1134 opts->shortname = VFAT_SFN_DISPLAY_WIN95 1135 | VFAT_SFN_CREATE_WIN95; 1136 break; 1137 case Opt_shortname_winnt: 1138 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1139 | VFAT_SFN_CREATE_WINNT; 1140 break; 1141 case Opt_shortname_mixed: 1142 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1143 | VFAT_SFN_CREATE_WIN95; 1144 break; 1145 case Opt_utf8_no: /* 0 or no or false */ 1146 opts->utf8 = 0; 1147 break; 1148 case Opt_utf8_yes: /* empty or 1 or yes or true */ 1149 opts->utf8 = 1; 1150 break; 1151 case Opt_uni_xl_no: /* 0 or no or false */ 1152 opts->unicode_xlate = 0; 1153 break; 1154 case Opt_uni_xl_yes: /* empty or 1 or yes or true */ 1155 opts->unicode_xlate = 1; 1156 break; 1157 case Opt_nonumtail_no: /* 0 or no or false */ 1158 opts->numtail = 1; /* negated option */ 1159 break; 1160 case Opt_nonumtail_yes: /* empty or 1 or yes or true */ 1161 opts->numtail = 0; /* negated option */ 1162 break; 1163 case Opt_rodir: 1164 opts->rodir = 1; 1165 break; 1166 case Opt_discard: 1167 opts->discard = 1; 1168 break; 1169 1170 /* obsolete mount options */ 1171 case Opt_obsolate: 1172 fat_msg(sb, KERN_INFO, "\"%s\" option is obsolete, " 1173 "not supported now", p); 1174 break; 1175 /* unknown option */ 1176 default: 1177 if (!silent) { 1178 fat_msg(sb, KERN_ERR, 1179 "Unrecognized mount option \"%s\" " 1180 "or missing value", p); 1181 } 1182 return -EINVAL; 1183 } 1184 } 1185 1186 out: 1187 /* UTF-8 doesn't provide FAT semantics */ 1188 if (!strcmp(opts->iocharset, "utf8")) { 1189 fat_msg(sb, KERN_ERR, "utf8 is not a recommended IO charset" 1190 " for FAT filesystems, filesystem will be " 1191 "case sensitive!\n"); 1192 } 1193 1194 /* If user doesn't specify allow_utime, it's initialized from dmask. */ 1195 if (opts->allow_utime == (unsigned short)-1) 1196 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH); 1197 if (opts->unicode_xlate) 1198 opts->utf8 = 0; 1199 1200 return 0; 1201 } 1202 1203 static int fat_read_root(struct inode *inode) 1204 { 1205 struct super_block *sb = inode->i_sb; 1206 struct msdos_sb_info *sbi = MSDOS_SB(sb); 1207 int error; 1208 1209 MSDOS_I(inode)->i_pos = 0; 1210 inode->i_uid = sbi->options.fs_uid; 1211 inode->i_gid = sbi->options.fs_gid; 1212 inode->i_version++; 1213 inode->i_generation = 0; 1214 inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO); 1215 inode->i_op = sbi->dir_ops; 1216 inode->i_fop = &fat_dir_operations; 1217 if (sbi->fat_bits == 32) { 1218 MSDOS_I(inode)->i_start = sbi->root_cluster; 1219 error = fat_calc_dir_size(inode); 1220 if (error < 0) 1221 return error; 1222 } else { 1223 MSDOS_I(inode)->i_start = 0; 1224 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry); 1225 } 1226 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 1227 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 1228 MSDOS_I(inode)->i_logstart = 0; 1229 MSDOS_I(inode)->mmu_private = inode->i_size; 1230 1231 fat_save_attrs(inode, ATTR_DIR); 1232 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0; 1233 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0; 1234 inode->i_nlink = fat_subdirs(inode)+2; 1235 1236 return 0; 1237 } 1238 1239 /* 1240 * Read the super block of an MS-DOS FS. 1241 */ 1242 int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat, 1243 void (*setup)(struct super_block *)) 1244 { 1245 struct inode *root_inode = NULL, *fat_inode = NULL; 1246 struct buffer_head *bh; 1247 struct fat_boot_sector *b; 1248 struct msdos_sb_info *sbi; 1249 u16 logical_sector_size; 1250 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors; 1251 int debug; 1252 unsigned int media; 1253 long error; 1254 char buf[50]; 1255 1256 /* 1257 * GFP_KERNEL is ok here, because while we do hold the 1258 * supeblock lock, memory pressure can't call back into 1259 * the filesystem, since we're only just about to mount 1260 * it and have no inodes etc active! 1261 */ 1262 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL); 1263 if (!sbi) 1264 return -ENOMEM; 1265 sb->s_fs_info = sbi; 1266 1267 sb->s_flags |= MS_NODIRATIME; 1268 sb->s_magic = MSDOS_SUPER_MAGIC; 1269 sb->s_op = &fat_sops; 1270 sb->s_export_op = &fat_export_ops; 1271 ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL, 1272 DEFAULT_RATELIMIT_BURST); 1273 1274 error = parse_options(sb, data, isvfat, silent, &debug, &sbi->options); 1275 if (error) 1276 goto out_fail; 1277 1278 setup(sb); /* flavour-specific stuff that needs options */ 1279 1280 error = -EIO; 1281 sb_min_blocksize(sb, 512); 1282 bh = sb_bread(sb, 0); 1283 if (bh == NULL) { 1284 fat_msg(sb, KERN_ERR, "unable to read boot sector"); 1285 goto out_fail; 1286 } 1287 1288 b = (struct fat_boot_sector *) bh->b_data; 1289 if (!b->reserved) { 1290 if (!silent) 1291 fat_msg(sb, KERN_ERR, "bogus number of reserved sectors"); 1292 brelse(bh); 1293 goto out_invalid; 1294 } 1295 if (!b->fats) { 1296 if (!silent) 1297 fat_msg(sb, KERN_ERR, "bogus number of FAT structure"); 1298 brelse(bh); 1299 goto out_invalid; 1300 } 1301 1302 /* 1303 * Earlier we checked here that b->secs_track and b->head are nonzero, 1304 * but it turns out valid FAT filesystems can have zero there. 1305 */ 1306 1307 media = b->media; 1308 if (!fat_valid_media(media)) { 1309 if (!silent) 1310 fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)", 1311 media); 1312 brelse(bh); 1313 goto out_invalid; 1314 } 1315 logical_sector_size = get_unaligned_le16(&b->sector_size); 1316 if (!is_power_of_2(logical_sector_size) 1317 || (logical_sector_size < 512) 1318 || (logical_sector_size > 4096)) { 1319 if (!silent) 1320 fat_msg(sb, KERN_ERR, "bogus logical sector size %u", 1321 logical_sector_size); 1322 brelse(bh); 1323 goto out_invalid; 1324 } 1325 sbi->sec_per_clus = b->sec_per_clus; 1326 if (!is_power_of_2(sbi->sec_per_clus)) { 1327 if (!silent) 1328 fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u", 1329 sbi->sec_per_clus); 1330 brelse(bh); 1331 goto out_invalid; 1332 } 1333 1334 if (logical_sector_size < sb->s_blocksize) { 1335 fat_msg(sb, KERN_ERR, "logical sector size too small for device" 1336 " (logical sector size = %u)", logical_sector_size); 1337 brelse(bh); 1338 goto out_fail; 1339 } 1340 if (logical_sector_size > sb->s_blocksize) { 1341 brelse(bh); 1342 1343 if (!sb_set_blocksize(sb, logical_sector_size)) { 1344 fat_msg(sb, KERN_ERR, "unable to set blocksize %u", 1345 logical_sector_size); 1346 goto out_fail; 1347 } 1348 bh = sb_bread(sb, 0); 1349 if (bh == NULL) { 1350 fat_msg(sb, KERN_ERR, "unable to read boot sector" 1351 " (logical sector size = %lu)", 1352 sb->s_blocksize); 1353 goto out_fail; 1354 } 1355 b = (struct fat_boot_sector *) bh->b_data; 1356 } 1357 1358 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus; 1359 sbi->cluster_bits = ffs(sbi->cluster_size) - 1; 1360 sbi->fats = b->fats; 1361 sbi->fat_bits = 0; /* Don't know yet */ 1362 sbi->fat_start = le16_to_cpu(b->reserved); 1363 sbi->fat_length = le16_to_cpu(b->fat_length); 1364 sbi->root_cluster = 0; 1365 sbi->free_clusters = -1; /* Don't know yet */ 1366 sbi->free_clus_valid = 0; 1367 sbi->prev_free = FAT_START_ENT; 1368 1369 if (!sbi->fat_length && b->fat32_length) { 1370 struct fat_boot_fsinfo *fsinfo; 1371 struct buffer_head *fsinfo_bh; 1372 1373 /* Must be FAT32 */ 1374 sbi->fat_bits = 32; 1375 sbi->fat_length = le32_to_cpu(b->fat32_length); 1376 sbi->root_cluster = le32_to_cpu(b->root_cluster); 1377 1378 sb->s_maxbytes = 0xffffffff; 1379 1380 /* MC - if info_sector is 0, don't multiply by 0 */ 1381 sbi->fsinfo_sector = le16_to_cpu(b->info_sector); 1382 if (sbi->fsinfo_sector == 0) 1383 sbi->fsinfo_sector = 1; 1384 1385 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector); 1386 if (fsinfo_bh == NULL) { 1387 fat_msg(sb, KERN_ERR, "bread failed, FSINFO block" 1388 " (sector = %lu)", sbi->fsinfo_sector); 1389 brelse(bh); 1390 goto out_fail; 1391 } 1392 1393 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data; 1394 if (!IS_FSINFO(fsinfo)) { 1395 fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: " 1396 "0x%08x, 0x%08x (sector = %lu)", 1397 le32_to_cpu(fsinfo->signature1), 1398 le32_to_cpu(fsinfo->signature2), 1399 sbi->fsinfo_sector); 1400 } else { 1401 if (sbi->options.usefree) 1402 sbi->free_clus_valid = 1; 1403 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters); 1404 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster); 1405 } 1406 1407 brelse(fsinfo_bh); 1408 } 1409 1410 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry); 1411 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1; 1412 1413 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length; 1414 sbi->dir_entries = get_unaligned_le16(&b->dir_entries); 1415 if (sbi->dir_entries & (sbi->dir_per_block - 1)) { 1416 if (!silent) 1417 fat_msg(sb, KERN_ERR, "bogus directroy-entries per block" 1418 " (%u)", sbi->dir_entries); 1419 brelse(bh); 1420 goto out_invalid; 1421 } 1422 1423 rootdir_sectors = sbi->dir_entries 1424 * sizeof(struct msdos_dir_entry) / sb->s_blocksize; 1425 sbi->data_start = sbi->dir_start + rootdir_sectors; 1426 total_sectors = get_unaligned_le16(&b->sectors); 1427 if (total_sectors == 0) 1428 total_sectors = le32_to_cpu(b->total_sect); 1429 1430 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus; 1431 1432 if (sbi->fat_bits != 32) 1433 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12; 1434 1435 /* check that FAT table does not overflow */ 1436 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits; 1437 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT); 1438 if (total_clusters > MAX_FAT(sb)) { 1439 if (!silent) 1440 fat_msg(sb, KERN_ERR, "count of clusters too big (%u)", 1441 total_clusters); 1442 brelse(bh); 1443 goto out_invalid; 1444 } 1445 1446 sbi->max_cluster = total_clusters + FAT_START_ENT; 1447 /* check the free_clusters, it's not necessarily correct */ 1448 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters) 1449 sbi->free_clusters = -1; 1450 /* check the prev_free, it's not necessarily correct */ 1451 sbi->prev_free %= sbi->max_cluster; 1452 if (sbi->prev_free < FAT_START_ENT) 1453 sbi->prev_free = FAT_START_ENT; 1454 1455 brelse(bh); 1456 1457 /* set up enough so that it can read an inode */ 1458 fat_hash_init(sb); 1459 fat_ent_access_init(sb); 1460 1461 /* 1462 * The low byte of FAT's first entry must have same value with 1463 * media-field. But in real world, too many devices is 1464 * writing wrong value. So, removed that validity check. 1465 * 1466 * if (FAT_FIRST_ENT(sb, media) != first) 1467 */ 1468 1469 error = -EINVAL; 1470 sprintf(buf, "cp%d", sbi->options.codepage); 1471 sbi->nls_disk = load_nls(buf); 1472 if (!sbi->nls_disk) { 1473 fat_msg(sb, KERN_ERR, "codepage %s not found", buf); 1474 goto out_fail; 1475 } 1476 1477 /* FIXME: utf8 is using iocharset for upper/lower conversion */ 1478 if (sbi->options.isvfat) { 1479 sbi->nls_io = load_nls(sbi->options.iocharset); 1480 if (!sbi->nls_io) { 1481 fat_msg(sb, KERN_ERR, "IO charset %s not found", 1482 sbi->options.iocharset); 1483 goto out_fail; 1484 } 1485 } 1486 1487 error = -ENOMEM; 1488 fat_inode = new_inode(sb); 1489 if (!fat_inode) 1490 goto out_fail; 1491 MSDOS_I(fat_inode)->i_pos = 0; 1492 sbi->fat_inode = fat_inode; 1493 root_inode = new_inode(sb); 1494 if (!root_inode) 1495 goto out_fail; 1496 root_inode->i_ino = MSDOS_ROOT_INO; 1497 root_inode->i_version = 1; 1498 error = fat_read_root(root_inode); 1499 if (error < 0) 1500 goto out_fail; 1501 error = -ENOMEM; 1502 insert_inode_hash(root_inode); 1503 sb->s_root = d_alloc_root(root_inode); 1504 if (!sb->s_root) { 1505 fat_msg(sb, KERN_ERR, "get root inode failed"); 1506 goto out_fail; 1507 } 1508 1509 return 0; 1510 1511 out_invalid: 1512 error = -EINVAL; 1513 if (!silent) 1514 fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem"); 1515 1516 out_fail: 1517 if (fat_inode) 1518 iput(fat_inode); 1519 if (root_inode) 1520 iput(root_inode); 1521 unload_nls(sbi->nls_io); 1522 unload_nls(sbi->nls_disk); 1523 if (sbi->options.iocharset != fat_default_iocharset) 1524 kfree(sbi->options.iocharset); 1525 sb->s_fs_info = NULL; 1526 kfree(sbi); 1527 return error; 1528 } 1529 1530 EXPORT_SYMBOL_GPL(fat_fill_super); 1531 1532 /* 1533 * helper function for fat_flush_inodes. This writes both the inode 1534 * and the file data blocks, waiting for in flight data blocks before 1535 * the start of the call. It does not wait for any io started 1536 * during the call 1537 */ 1538 static int writeback_inode(struct inode *inode) 1539 { 1540 1541 int ret; 1542 struct address_space *mapping = inode->i_mapping; 1543 struct writeback_control wbc = { 1544 .sync_mode = WB_SYNC_NONE, 1545 .nr_to_write = 0, 1546 }; 1547 /* if we used WB_SYNC_ALL, sync_inode waits for the io for the 1548 * inode to finish. So WB_SYNC_NONE is sent down to sync_inode 1549 * and filemap_fdatawrite is used for the data blocks 1550 */ 1551 ret = sync_inode(inode, &wbc); 1552 if (!ret) 1553 ret = filemap_fdatawrite(mapping); 1554 return ret; 1555 } 1556 1557 /* 1558 * write data and metadata corresponding to i1 and i2. The io is 1559 * started but we do not wait for any of it to finish. 1560 * 1561 * filemap_flush is used for the block device, so if there is a dirty 1562 * page for a block already in flight, we will not wait and start the 1563 * io over again 1564 */ 1565 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2) 1566 { 1567 int ret = 0; 1568 if (!MSDOS_SB(sb)->options.flush) 1569 return 0; 1570 if (i1) 1571 ret = writeback_inode(i1); 1572 if (!ret && i2) 1573 ret = writeback_inode(i2); 1574 if (!ret) { 1575 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping; 1576 ret = filemap_flush(mapping); 1577 } 1578 return ret; 1579 } 1580 EXPORT_SYMBOL_GPL(fat_flush_inodes); 1581 1582 static int __init init_fat_fs(void) 1583 { 1584 int err; 1585 1586 err = fat_cache_init(); 1587 if (err) 1588 return err; 1589 1590 err = fat_init_inodecache(); 1591 if (err) 1592 goto failed; 1593 1594 return 0; 1595 1596 failed: 1597 fat_cache_destroy(); 1598 return err; 1599 } 1600 1601 static void __exit exit_fat_fs(void) 1602 { 1603 fat_cache_destroy(); 1604 fat_destroy_inodecache(); 1605 } 1606 1607 module_init(init_fat_fs) 1608 module_exit(exit_fat_fs) 1609 1610 MODULE_LICENSE("GPL"); 1611