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