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/mount.h> 22 #include <linux/aio.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 <linux/blkdev.h> 30 #include <asm/unaligned.h> 31 #include "fat.h" 32 33 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET 34 /* if user don't select VFAT, this is undefined. */ 35 #define CONFIG_FAT_DEFAULT_IOCHARSET "" 36 #endif 37 38 #define KB_IN_SECTORS 2 39 40 /* 41 * A deserialized copy of the on-disk structure laid out in struct 42 * fat_boot_sector. 43 */ 44 struct fat_bios_param_block { 45 u16 fat_sector_size; 46 u8 fat_sec_per_clus; 47 u16 fat_reserved; 48 u8 fat_fats; 49 u16 fat_dir_entries; 50 u16 fat_sectors; 51 u16 fat_fat_length; 52 u32 fat_total_sect; 53 54 u8 fat16_state; 55 u32 fat16_vol_id; 56 57 u32 fat32_length; 58 u32 fat32_root_cluster; 59 u16 fat32_info_sector; 60 u8 fat32_state; 61 u32 fat32_vol_id; 62 }; 63 64 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE; 65 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET; 66 67 static struct fat_floppy_defaults { 68 unsigned nr_sectors; 69 unsigned sec_per_clus; 70 unsigned dir_entries; 71 unsigned media; 72 unsigned fat_length; 73 } floppy_defaults[] = { 74 { 75 .nr_sectors = 160 * KB_IN_SECTORS, 76 .sec_per_clus = 1, 77 .dir_entries = 64, 78 .media = 0xFE, 79 .fat_length = 1, 80 }, 81 { 82 .nr_sectors = 180 * KB_IN_SECTORS, 83 .sec_per_clus = 1, 84 .dir_entries = 64, 85 .media = 0xFC, 86 .fat_length = 2, 87 }, 88 { 89 .nr_sectors = 320 * KB_IN_SECTORS, 90 .sec_per_clus = 2, 91 .dir_entries = 112, 92 .media = 0xFF, 93 .fat_length = 1, 94 }, 95 { 96 .nr_sectors = 360 * KB_IN_SECTORS, 97 .sec_per_clus = 2, 98 .dir_entries = 112, 99 .media = 0xFD, 100 .fat_length = 2, 101 }, 102 }; 103 104 static int fat_add_cluster(struct inode *inode) 105 { 106 int err, cluster; 107 108 err = fat_alloc_clusters(inode, &cluster, 1); 109 if (err) 110 return err; 111 /* FIXME: this cluster should be added after data of this 112 * cluster is writed */ 113 err = fat_chain_add(inode, cluster, 1); 114 if (err) 115 fat_free_clusters(inode, cluster); 116 return err; 117 } 118 119 static inline int __fat_get_block(struct inode *inode, sector_t iblock, 120 unsigned long *max_blocks, 121 struct buffer_head *bh_result, int create) 122 { 123 struct super_block *sb = inode->i_sb; 124 struct msdos_sb_info *sbi = MSDOS_SB(sb); 125 unsigned long mapped_blocks; 126 sector_t phys; 127 int err, offset; 128 129 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create); 130 if (err) 131 return err; 132 if (phys) { 133 map_bh(bh_result, sb, phys); 134 *max_blocks = min(mapped_blocks, *max_blocks); 135 return 0; 136 } 137 if (!create) 138 return 0; 139 140 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) { 141 fat_fs_error(sb, "corrupted file size (i_pos %lld, %lld)", 142 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private); 143 return -EIO; 144 } 145 146 offset = (unsigned long)iblock & (sbi->sec_per_clus - 1); 147 if (!offset) { 148 /* TODO: multiple cluster allocation would be desirable. */ 149 err = fat_add_cluster(inode); 150 if (err) 151 return err; 152 } 153 /* available blocks on this cluster */ 154 mapped_blocks = sbi->sec_per_clus - offset; 155 156 *max_blocks = min(mapped_blocks, *max_blocks); 157 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits; 158 159 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create); 160 if (err) 161 return err; 162 163 BUG_ON(!phys); 164 BUG_ON(*max_blocks != mapped_blocks); 165 set_buffer_new(bh_result); 166 map_bh(bh_result, sb, phys); 167 168 return 0; 169 } 170 171 static int fat_get_block(struct inode *inode, sector_t iblock, 172 struct buffer_head *bh_result, int create) 173 { 174 struct super_block *sb = inode->i_sb; 175 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits; 176 int err; 177 178 err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create); 179 if (err) 180 return err; 181 bh_result->b_size = max_blocks << sb->s_blocksize_bits; 182 return 0; 183 } 184 185 static int fat_writepage(struct page *page, struct writeback_control *wbc) 186 { 187 return block_write_full_page(page, fat_get_block, wbc); 188 } 189 190 static int fat_writepages(struct address_space *mapping, 191 struct writeback_control *wbc) 192 { 193 return mpage_writepages(mapping, wbc, fat_get_block); 194 } 195 196 static int fat_readpage(struct file *file, struct page *page) 197 { 198 return mpage_readpage(page, fat_get_block); 199 } 200 201 static int fat_readpages(struct file *file, struct address_space *mapping, 202 struct list_head *pages, unsigned nr_pages) 203 { 204 return mpage_readpages(mapping, pages, nr_pages, fat_get_block); 205 } 206 207 static void fat_write_failed(struct address_space *mapping, loff_t to) 208 { 209 struct inode *inode = mapping->host; 210 211 if (to > inode->i_size) { 212 truncate_pagecache(inode, inode->i_size); 213 fat_truncate_blocks(inode, inode->i_size); 214 } 215 } 216 217 static int fat_write_begin(struct file *file, struct address_space *mapping, 218 loff_t pos, unsigned len, unsigned flags, 219 struct page **pagep, void **fsdata) 220 { 221 int err; 222 223 *pagep = NULL; 224 err = cont_write_begin(file, mapping, pos, len, flags, 225 pagep, fsdata, fat_get_block, 226 &MSDOS_I(mapping->host)->mmu_private); 227 if (err < 0) 228 fat_write_failed(mapping, pos + len); 229 return err; 230 } 231 232 static int fat_write_end(struct file *file, struct address_space *mapping, 233 loff_t pos, unsigned len, unsigned copied, 234 struct page *pagep, void *fsdata) 235 { 236 struct inode *inode = mapping->host; 237 int err; 238 err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata); 239 if (err < len) 240 fat_write_failed(mapping, pos + len); 241 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) { 242 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC; 243 MSDOS_I(inode)->i_attrs |= ATTR_ARCH; 244 mark_inode_dirty(inode); 245 } 246 return err; 247 } 248 249 static ssize_t fat_direct_IO(int rw, struct kiocb *iocb, 250 struct iov_iter *iter, 251 loff_t offset) 252 { 253 struct file *file = iocb->ki_filp; 254 struct address_space *mapping = file->f_mapping; 255 struct inode *inode = mapping->host; 256 size_t count = iov_iter_count(iter); 257 ssize_t ret; 258 259 if (rw == WRITE) { 260 /* 261 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(), 262 * so we need to update the ->mmu_private to block boundary. 263 * 264 * But we must fill the remaining area or hole by nul for 265 * updating ->mmu_private. 266 * 267 * Return 0, and fallback to normal buffered write. 268 */ 269 loff_t size = offset + count; 270 if (MSDOS_I(inode)->mmu_private < size) 271 return 0; 272 } 273 274 /* 275 * FAT need to use the DIO_LOCKING for avoiding the race 276 * condition of fat_get_block() and ->truncate(). 277 */ 278 ret = blockdev_direct_IO(rw, iocb, inode, iter, offset, fat_get_block); 279 if (ret < 0 && (rw & WRITE)) 280 fat_write_failed(mapping, offset + count); 281 282 return ret; 283 } 284 285 static sector_t _fat_bmap(struct address_space *mapping, sector_t block) 286 { 287 sector_t blocknr; 288 289 /* fat_get_cluster() assumes the requested blocknr isn't truncated. */ 290 down_read(&MSDOS_I(mapping->host)->truncate_lock); 291 blocknr = generic_block_bmap(mapping, block, fat_get_block); 292 up_read(&MSDOS_I(mapping->host)->truncate_lock); 293 294 return blocknr; 295 } 296 297 static const struct address_space_operations fat_aops = { 298 .readpage = fat_readpage, 299 .readpages = fat_readpages, 300 .writepage = fat_writepage, 301 .writepages = fat_writepages, 302 .write_begin = fat_write_begin, 303 .write_end = fat_write_end, 304 .direct_IO = fat_direct_IO, 305 .bmap = _fat_bmap 306 }; 307 308 /* 309 * New FAT inode stuff. We do the following: 310 * a) i_ino is constant and has nothing with on-disk location. 311 * b) FAT manages its own cache of directory entries. 312 * c) *This* cache is indexed by on-disk location. 313 * d) inode has an associated directory entry, all right, but 314 * it may be unhashed. 315 * e) currently entries are stored within struct inode. That should 316 * change. 317 * f) we deal with races in the following way: 318 * 1. readdir() and lookup() do FAT-dir-cache lookup. 319 * 2. rename() unhashes the F-d-c entry and rehashes it in 320 * a new place. 321 * 3. unlink() and rmdir() unhash F-d-c entry. 322 * 4. fat_write_inode() checks whether the thing is unhashed. 323 * If it is we silently return. If it isn't we do bread(), 324 * check if the location is still valid and retry if it 325 * isn't. Otherwise we do changes. 326 * 5. Spinlock is used to protect hash/unhash/location check/lookup 327 * 6. fat_evict_inode() unhashes the F-d-c entry. 328 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry 329 * and consider negative result as cache miss. 330 */ 331 332 static void fat_hash_init(struct super_block *sb) 333 { 334 struct msdos_sb_info *sbi = MSDOS_SB(sb); 335 int i; 336 337 spin_lock_init(&sbi->inode_hash_lock); 338 for (i = 0; i < FAT_HASH_SIZE; i++) 339 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]); 340 } 341 342 static inline unsigned long fat_hash(loff_t i_pos) 343 { 344 return hash_32(i_pos, FAT_HASH_BITS); 345 } 346 347 static void dir_hash_init(struct super_block *sb) 348 { 349 struct msdos_sb_info *sbi = MSDOS_SB(sb); 350 int i; 351 352 spin_lock_init(&sbi->dir_hash_lock); 353 for (i = 0; i < FAT_HASH_SIZE; i++) 354 INIT_HLIST_HEAD(&sbi->dir_hashtable[i]); 355 } 356 357 void fat_attach(struct inode *inode, loff_t i_pos) 358 { 359 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 360 361 if (inode->i_ino != MSDOS_ROOT_INO) { 362 struct hlist_head *head = sbi->inode_hashtable 363 + fat_hash(i_pos); 364 365 spin_lock(&sbi->inode_hash_lock); 366 MSDOS_I(inode)->i_pos = i_pos; 367 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head); 368 spin_unlock(&sbi->inode_hash_lock); 369 } 370 371 /* If NFS support is enabled, cache the mapping of start cluster 372 * to directory inode. This is used during reconnection of 373 * dentries to the filesystem root. 374 */ 375 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) { 376 struct hlist_head *d_head = sbi->dir_hashtable; 377 d_head += fat_dir_hash(MSDOS_I(inode)->i_logstart); 378 379 spin_lock(&sbi->dir_hash_lock); 380 hlist_add_head(&MSDOS_I(inode)->i_dir_hash, d_head); 381 spin_unlock(&sbi->dir_hash_lock); 382 } 383 } 384 EXPORT_SYMBOL_GPL(fat_attach); 385 386 void fat_detach(struct inode *inode) 387 { 388 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 389 spin_lock(&sbi->inode_hash_lock); 390 MSDOS_I(inode)->i_pos = 0; 391 hlist_del_init(&MSDOS_I(inode)->i_fat_hash); 392 spin_unlock(&sbi->inode_hash_lock); 393 394 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) { 395 spin_lock(&sbi->dir_hash_lock); 396 hlist_del_init(&MSDOS_I(inode)->i_dir_hash); 397 spin_unlock(&sbi->dir_hash_lock); 398 } 399 } 400 EXPORT_SYMBOL_GPL(fat_detach); 401 402 struct inode *fat_iget(struct super_block *sb, loff_t i_pos) 403 { 404 struct msdos_sb_info *sbi = MSDOS_SB(sb); 405 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos); 406 struct msdos_inode_info *i; 407 struct inode *inode = NULL; 408 409 spin_lock(&sbi->inode_hash_lock); 410 hlist_for_each_entry(i, head, i_fat_hash) { 411 BUG_ON(i->vfs_inode.i_sb != sb); 412 if (i->i_pos != i_pos) 413 continue; 414 inode = igrab(&i->vfs_inode); 415 if (inode) 416 break; 417 } 418 spin_unlock(&sbi->inode_hash_lock); 419 return inode; 420 } 421 422 static int is_exec(unsigned char *extension) 423 { 424 unsigned char exe_extensions[] = "EXECOMBAT", *walk; 425 426 for (walk = exe_extensions; *walk; walk += 3) 427 if (!strncmp(extension, walk, 3)) 428 return 1; 429 return 0; 430 } 431 432 static int fat_calc_dir_size(struct inode *inode) 433 { 434 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 435 int ret, fclus, dclus; 436 437 inode->i_size = 0; 438 if (MSDOS_I(inode)->i_start == 0) 439 return 0; 440 441 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); 442 if (ret < 0) 443 return ret; 444 inode->i_size = (fclus + 1) << sbi->cluster_bits; 445 446 return 0; 447 } 448 449 /* doesn't deal with root inode */ 450 int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de) 451 { 452 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 453 int error; 454 455 MSDOS_I(inode)->i_pos = 0; 456 inode->i_uid = sbi->options.fs_uid; 457 inode->i_gid = sbi->options.fs_gid; 458 inode->i_version++; 459 inode->i_generation = get_seconds(); 460 461 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) { 462 inode->i_generation &= ~1; 463 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO); 464 inode->i_op = sbi->dir_ops; 465 inode->i_fop = &fat_dir_operations; 466 467 MSDOS_I(inode)->i_start = fat_get_start(sbi, de); 468 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 469 error = fat_calc_dir_size(inode); 470 if (error < 0) 471 return error; 472 MSDOS_I(inode)->mmu_private = inode->i_size; 473 474 set_nlink(inode, fat_subdirs(inode)); 475 } else { /* not a directory */ 476 inode->i_generation |= 1; 477 inode->i_mode = fat_make_mode(sbi, de->attr, 478 ((sbi->options.showexec && !is_exec(de->name + 8)) 479 ? S_IRUGO|S_IWUGO : S_IRWXUGO)); 480 MSDOS_I(inode)->i_start = fat_get_start(sbi, de); 481 482 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 483 inode->i_size = le32_to_cpu(de->size); 484 inode->i_op = &fat_file_inode_operations; 485 inode->i_fop = &fat_file_operations; 486 inode->i_mapping->a_ops = &fat_aops; 487 MSDOS_I(inode)->mmu_private = inode->i_size; 488 } 489 if (de->attr & ATTR_SYS) { 490 if (sbi->options.sys_immutable) 491 inode->i_flags |= S_IMMUTABLE; 492 } 493 fat_save_attrs(inode, de->attr); 494 495 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 496 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 497 498 fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0); 499 if (sbi->options.isvfat) { 500 fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime, 501 de->cdate, de->ctime_cs); 502 fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0); 503 } else 504 inode->i_ctime = inode->i_atime = inode->i_mtime; 505 506 return 0; 507 } 508 509 static inline void fat_lock_build_inode(struct msdos_sb_info *sbi) 510 { 511 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO) 512 mutex_lock(&sbi->nfs_build_inode_lock); 513 } 514 515 static inline void fat_unlock_build_inode(struct msdos_sb_info *sbi) 516 { 517 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO) 518 mutex_unlock(&sbi->nfs_build_inode_lock); 519 } 520 521 struct inode *fat_build_inode(struct super_block *sb, 522 struct msdos_dir_entry *de, loff_t i_pos) 523 { 524 struct inode *inode; 525 int err; 526 527 fat_lock_build_inode(MSDOS_SB(sb)); 528 inode = fat_iget(sb, i_pos); 529 if (inode) 530 goto out; 531 inode = new_inode(sb); 532 if (!inode) { 533 inode = ERR_PTR(-ENOMEM); 534 goto out; 535 } 536 inode->i_ino = iunique(sb, MSDOS_ROOT_INO); 537 inode->i_version = 1; 538 err = fat_fill_inode(inode, de); 539 if (err) { 540 iput(inode); 541 inode = ERR_PTR(err); 542 goto out; 543 } 544 fat_attach(inode, i_pos); 545 insert_inode_hash(inode); 546 out: 547 fat_unlock_build_inode(MSDOS_SB(sb)); 548 return inode; 549 } 550 551 EXPORT_SYMBOL_GPL(fat_build_inode); 552 553 static void fat_evict_inode(struct inode *inode) 554 { 555 truncate_inode_pages_final(&inode->i_data); 556 if (!inode->i_nlink) { 557 inode->i_size = 0; 558 fat_truncate_blocks(inode, 0); 559 } 560 invalidate_inode_buffers(inode); 561 clear_inode(inode); 562 fat_cache_inval_inode(inode); 563 fat_detach(inode); 564 } 565 566 static void fat_set_state(struct super_block *sb, 567 unsigned int set, unsigned int force) 568 { 569 struct buffer_head *bh; 570 struct fat_boot_sector *b; 571 struct msdos_sb_info *sbi = sb->s_fs_info; 572 573 /* do not change any thing if mounted read only */ 574 if ((sb->s_flags & MS_RDONLY) && !force) 575 return; 576 577 /* do not change state if fs was dirty */ 578 if (sbi->dirty) { 579 /* warn only on set (mount). */ 580 if (set) 581 fat_msg(sb, KERN_WARNING, "Volume was not properly " 582 "unmounted. Some data may be corrupt. " 583 "Please run fsck."); 584 return; 585 } 586 587 bh = sb_bread(sb, 0); 588 if (bh == NULL) { 589 fat_msg(sb, KERN_ERR, "unable to read boot sector " 590 "to mark fs as dirty"); 591 return; 592 } 593 594 b = (struct fat_boot_sector *) bh->b_data; 595 596 if (sbi->fat_bits == 32) { 597 if (set) 598 b->fat32.state |= FAT_STATE_DIRTY; 599 else 600 b->fat32.state &= ~FAT_STATE_DIRTY; 601 } else /* fat 16 and 12 */ { 602 if (set) 603 b->fat16.state |= FAT_STATE_DIRTY; 604 else 605 b->fat16.state &= ~FAT_STATE_DIRTY; 606 } 607 608 mark_buffer_dirty(bh); 609 sync_dirty_buffer(bh); 610 brelse(bh); 611 } 612 613 static void delayed_free(struct rcu_head *p) 614 { 615 struct msdos_sb_info *sbi = container_of(p, struct msdos_sb_info, rcu); 616 unload_nls(sbi->nls_disk); 617 unload_nls(sbi->nls_io); 618 if (sbi->options.iocharset != fat_default_iocharset) 619 kfree(sbi->options.iocharset); 620 kfree(sbi); 621 } 622 623 static void fat_put_super(struct super_block *sb) 624 { 625 struct msdos_sb_info *sbi = MSDOS_SB(sb); 626 627 fat_set_state(sb, 0, 0); 628 629 iput(sbi->fsinfo_inode); 630 iput(sbi->fat_inode); 631 632 call_rcu(&sbi->rcu, delayed_free); 633 } 634 635 static struct kmem_cache *fat_inode_cachep; 636 637 static struct inode *fat_alloc_inode(struct super_block *sb) 638 { 639 struct msdos_inode_info *ei; 640 ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS); 641 if (!ei) 642 return NULL; 643 644 init_rwsem(&ei->truncate_lock); 645 return &ei->vfs_inode; 646 } 647 648 static void fat_i_callback(struct rcu_head *head) 649 { 650 struct inode *inode = container_of(head, struct inode, i_rcu); 651 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode)); 652 } 653 654 static void fat_destroy_inode(struct inode *inode) 655 { 656 call_rcu(&inode->i_rcu, fat_i_callback); 657 } 658 659 static void init_once(void *foo) 660 { 661 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo; 662 663 spin_lock_init(&ei->cache_lru_lock); 664 ei->nr_caches = 0; 665 ei->cache_valid_id = FAT_CACHE_VALID + 1; 666 INIT_LIST_HEAD(&ei->cache_lru); 667 INIT_HLIST_NODE(&ei->i_fat_hash); 668 INIT_HLIST_NODE(&ei->i_dir_hash); 669 inode_init_once(&ei->vfs_inode); 670 } 671 672 static int __init fat_init_inodecache(void) 673 { 674 fat_inode_cachep = kmem_cache_create("fat_inode_cache", 675 sizeof(struct msdos_inode_info), 676 0, (SLAB_RECLAIM_ACCOUNT| 677 SLAB_MEM_SPREAD), 678 init_once); 679 if (fat_inode_cachep == NULL) 680 return -ENOMEM; 681 return 0; 682 } 683 684 static void __exit fat_destroy_inodecache(void) 685 { 686 /* 687 * Make sure all delayed rcu free inodes are flushed before we 688 * destroy cache. 689 */ 690 rcu_barrier(); 691 kmem_cache_destroy(fat_inode_cachep); 692 } 693 694 static int fat_remount(struct super_block *sb, int *flags, char *data) 695 { 696 int new_rdonly; 697 struct msdos_sb_info *sbi = MSDOS_SB(sb); 698 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME); 699 700 sync_filesystem(sb); 701 702 /* make sure we update state on remount. */ 703 new_rdonly = *flags & MS_RDONLY; 704 if (new_rdonly != (sb->s_flags & MS_RDONLY)) { 705 if (new_rdonly) 706 fat_set_state(sb, 0, 0); 707 else 708 fat_set_state(sb, 1, 1); 709 } 710 return 0; 711 } 712 713 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf) 714 { 715 struct super_block *sb = dentry->d_sb; 716 struct msdos_sb_info *sbi = MSDOS_SB(sb); 717 u64 id = huge_encode_dev(sb->s_bdev->bd_dev); 718 719 /* If the count of free cluster is still unknown, counts it here. */ 720 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) { 721 int err = fat_count_free_clusters(dentry->d_sb); 722 if (err) 723 return err; 724 } 725 726 buf->f_type = dentry->d_sb->s_magic; 727 buf->f_bsize = sbi->cluster_size; 728 buf->f_blocks = sbi->max_cluster - FAT_START_ENT; 729 buf->f_bfree = sbi->free_clusters; 730 buf->f_bavail = sbi->free_clusters; 731 buf->f_fsid.val[0] = (u32)id; 732 buf->f_fsid.val[1] = (u32)(id >> 32); 733 buf->f_namelen = 734 (sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE; 735 736 return 0; 737 } 738 739 static int __fat_write_inode(struct inode *inode, int wait) 740 { 741 struct super_block *sb = inode->i_sb; 742 struct msdos_sb_info *sbi = MSDOS_SB(sb); 743 struct buffer_head *bh; 744 struct msdos_dir_entry *raw_entry; 745 loff_t i_pos; 746 sector_t blocknr; 747 int err, offset; 748 749 if (inode->i_ino == MSDOS_ROOT_INO) 750 return 0; 751 752 retry: 753 i_pos = fat_i_pos_read(sbi, inode); 754 if (!i_pos) 755 return 0; 756 757 fat_get_blknr_offset(sbi, i_pos, &blocknr, &offset); 758 bh = sb_bread(sb, blocknr); 759 if (!bh) { 760 fat_msg(sb, KERN_ERR, "unable to read inode block " 761 "for updating (i_pos %lld)", i_pos); 762 return -EIO; 763 } 764 spin_lock(&sbi->inode_hash_lock); 765 if (i_pos != MSDOS_I(inode)->i_pos) { 766 spin_unlock(&sbi->inode_hash_lock); 767 brelse(bh); 768 goto retry; 769 } 770 771 raw_entry = &((struct msdos_dir_entry *) (bh->b_data))[offset]; 772 if (S_ISDIR(inode->i_mode)) 773 raw_entry->size = 0; 774 else 775 raw_entry->size = cpu_to_le32(inode->i_size); 776 raw_entry->attr = fat_make_attrs(inode); 777 fat_set_start(raw_entry, MSDOS_I(inode)->i_logstart); 778 fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time, 779 &raw_entry->date, NULL); 780 if (sbi->options.isvfat) { 781 __le16 atime; 782 fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime, 783 &raw_entry->cdate, &raw_entry->ctime_cs); 784 fat_time_unix2fat(sbi, &inode->i_atime, &atime, 785 &raw_entry->adate, NULL); 786 } 787 spin_unlock(&sbi->inode_hash_lock); 788 mark_buffer_dirty(bh); 789 err = 0; 790 if (wait) 791 err = sync_dirty_buffer(bh); 792 brelse(bh); 793 return err; 794 } 795 796 static int fat_write_inode(struct inode *inode, struct writeback_control *wbc) 797 { 798 int err; 799 800 if (inode->i_ino == MSDOS_FSINFO_INO) { 801 struct super_block *sb = inode->i_sb; 802 803 mutex_lock(&MSDOS_SB(sb)->s_lock); 804 err = fat_clusters_flush(sb); 805 mutex_unlock(&MSDOS_SB(sb)->s_lock); 806 } else 807 err = __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL); 808 809 return err; 810 } 811 812 int fat_sync_inode(struct inode *inode) 813 { 814 return __fat_write_inode(inode, 1); 815 } 816 817 EXPORT_SYMBOL_GPL(fat_sync_inode); 818 819 static int fat_show_options(struct seq_file *m, struct dentry *root); 820 static const struct super_operations fat_sops = { 821 .alloc_inode = fat_alloc_inode, 822 .destroy_inode = fat_destroy_inode, 823 .write_inode = fat_write_inode, 824 .evict_inode = fat_evict_inode, 825 .put_super = fat_put_super, 826 .statfs = fat_statfs, 827 .remount_fs = fat_remount, 828 829 .show_options = fat_show_options, 830 }; 831 832 static int fat_show_options(struct seq_file *m, struct dentry *root) 833 { 834 struct msdos_sb_info *sbi = MSDOS_SB(root->d_sb); 835 struct fat_mount_options *opts = &sbi->options; 836 int isvfat = opts->isvfat; 837 838 if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID)) 839 seq_printf(m, ",uid=%u", 840 from_kuid_munged(&init_user_ns, opts->fs_uid)); 841 if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID)) 842 seq_printf(m, ",gid=%u", 843 from_kgid_munged(&init_user_ns, opts->fs_gid)); 844 seq_printf(m, ",fmask=%04o", opts->fs_fmask); 845 seq_printf(m, ",dmask=%04o", opts->fs_dmask); 846 if (opts->allow_utime) 847 seq_printf(m, ",allow_utime=%04o", opts->allow_utime); 848 if (sbi->nls_disk) 849 /* strip "cp" prefix from displayed option */ 850 seq_printf(m, ",codepage=%s", &sbi->nls_disk->charset[2]); 851 if (isvfat) { 852 if (sbi->nls_io) 853 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset); 854 855 switch (opts->shortname) { 856 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95: 857 seq_puts(m, ",shortname=win95"); 858 break; 859 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT: 860 seq_puts(m, ",shortname=winnt"); 861 break; 862 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95: 863 seq_puts(m, ",shortname=mixed"); 864 break; 865 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95: 866 seq_puts(m, ",shortname=lower"); 867 break; 868 default: 869 seq_puts(m, ",shortname=unknown"); 870 break; 871 } 872 } 873 if (opts->name_check != 'n') 874 seq_printf(m, ",check=%c", opts->name_check); 875 if (opts->usefree) 876 seq_puts(m, ",usefree"); 877 if (opts->quiet) 878 seq_puts(m, ",quiet"); 879 if (opts->showexec) 880 seq_puts(m, ",showexec"); 881 if (opts->sys_immutable) 882 seq_puts(m, ",sys_immutable"); 883 if (!isvfat) { 884 if (opts->dotsOK) 885 seq_puts(m, ",dotsOK=yes"); 886 if (opts->nocase) 887 seq_puts(m, ",nocase"); 888 } else { 889 if (opts->utf8) 890 seq_puts(m, ",utf8"); 891 if (opts->unicode_xlate) 892 seq_puts(m, ",uni_xlate"); 893 if (!opts->numtail) 894 seq_puts(m, ",nonumtail"); 895 if (opts->rodir) 896 seq_puts(m, ",rodir"); 897 } 898 if (opts->flush) 899 seq_puts(m, ",flush"); 900 if (opts->tz_set) { 901 if (opts->time_offset) 902 seq_printf(m, ",time_offset=%d", opts->time_offset); 903 else 904 seq_puts(m, ",tz=UTC"); 905 } 906 if (opts->errors == FAT_ERRORS_CONT) 907 seq_puts(m, ",errors=continue"); 908 else if (opts->errors == FAT_ERRORS_PANIC) 909 seq_puts(m, ",errors=panic"); 910 else 911 seq_puts(m, ",errors=remount-ro"); 912 if (opts->nfs == FAT_NFS_NOSTALE_RO) 913 seq_puts(m, ",nfs=nostale_ro"); 914 else if (opts->nfs) 915 seq_puts(m, ",nfs=stale_rw"); 916 if (opts->discard) 917 seq_puts(m, ",discard"); 918 if (opts->dos1xfloppy) 919 seq_puts(m, ",dos1xfloppy"); 920 921 return 0; 922 } 923 924 enum { 925 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid, 926 Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage, 927 Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug, 928 Opt_immutable, Opt_dots, Opt_nodots, 929 Opt_charset, Opt_shortname_lower, Opt_shortname_win95, 930 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes, 931 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes, 932 Opt_obsolete, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont, 933 Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_time_offset, 934 Opt_nfs_stale_rw, Opt_nfs_nostale_ro, Opt_err, Opt_dos1xfloppy, 935 }; 936 937 static const match_table_t fat_tokens = { 938 {Opt_check_r, "check=relaxed"}, 939 {Opt_check_s, "check=strict"}, 940 {Opt_check_n, "check=normal"}, 941 {Opt_check_r, "check=r"}, 942 {Opt_check_s, "check=s"}, 943 {Opt_check_n, "check=n"}, 944 {Opt_uid, "uid=%u"}, 945 {Opt_gid, "gid=%u"}, 946 {Opt_umask, "umask=%o"}, 947 {Opt_dmask, "dmask=%o"}, 948 {Opt_fmask, "fmask=%o"}, 949 {Opt_allow_utime, "allow_utime=%o"}, 950 {Opt_codepage, "codepage=%u"}, 951 {Opt_usefree, "usefree"}, 952 {Opt_nocase, "nocase"}, 953 {Opt_quiet, "quiet"}, 954 {Opt_showexec, "showexec"}, 955 {Opt_debug, "debug"}, 956 {Opt_immutable, "sys_immutable"}, 957 {Opt_flush, "flush"}, 958 {Opt_tz_utc, "tz=UTC"}, 959 {Opt_time_offset, "time_offset=%d"}, 960 {Opt_err_cont, "errors=continue"}, 961 {Opt_err_panic, "errors=panic"}, 962 {Opt_err_ro, "errors=remount-ro"}, 963 {Opt_discard, "discard"}, 964 {Opt_nfs_stale_rw, "nfs"}, 965 {Opt_nfs_stale_rw, "nfs=stale_rw"}, 966 {Opt_nfs_nostale_ro, "nfs=nostale_ro"}, 967 {Opt_dos1xfloppy, "dos1xfloppy"}, 968 {Opt_obsolete, "conv=binary"}, 969 {Opt_obsolete, "conv=text"}, 970 {Opt_obsolete, "conv=auto"}, 971 {Opt_obsolete, "conv=b"}, 972 {Opt_obsolete, "conv=t"}, 973 {Opt_obsolete, "conv=a"}, 974 {Opt_obsolete, "fat=%u"}, 975 {Opt_obsolete, "blocksize=%u"}, 976 {Opt_obsolete, "cvf_format=%20s"}, 977 {Opt_obsolete, "cvf_options=%100s"}, 978 {Opt_obsolete, "posix"}, 979 {Opt_err, NULL}, 980 }; 981 static const match_table_t msdos_tokens = { 982 {Opt_nodots, "nodots"}, 983 {Opt_nodots, "dotsOK=no"}, 984 {Opt_dots, "dots"}, 985 {Opt_dots, "dotsOK=yes"}, 986 {Opt_err, NULL} 987 }; 988 static const match_table_t vfat_tokens = { 989 {Opt_charset, "iocharset=%s"}, 990 {Opt_shortname_lower, "shortname=lower"}, 991 {Opt_shortname_win95, "shortname=win95"}, 992 {Opt_shortname_winnt, "shortname=winnt"}, 993 {Opt_shortname_mixed, "shortname=mixed"}, 994 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */ 995 {Opt_utf8_no, "utf8=no"}, 996 {Opt_utf8_no, "utf8=false"}, 997 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */ 998 {Opt_utf8_yes, "utf8=yes"}, 999 {Opt_utf8_yes, "utf8=true"}, 1000 {Opt_utf8_yes, "utf8"}, 1001 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */ 1002 {Opt_uni_xl_no, "uni_xlate=no"}, 1003 {Opt_uni_xl_no, "uni_xlate=false"}, 1004 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */ 1005 {Opt_uni_xl_yes, "uni_xlate=yes"}, 1006 {Opt_uni_xl_yes, "uni_xlate=true"}, 1007 {Opt_uni_xl_yes, "uni_xlate"}, 1008 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */ 1009 {Opt_nonumtail_no, "nonumtail=no"}, 1010 {Opt_nonumtail_no, "nonumtail=false"}, 1011 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */ 1012 {Opt_nonumtail_yes, "nonumtail=yes"}, 1013 {Opt_nonumtail_yes, "nonumtail=true"}, 1014 {Opt_nonumtail_yes, "nonumtail"}, 1015 {Opt_rodir, "rodir"}, 1016 {Opt_err, NULL} 1017 }; 1018 1019 static int parse_options(struct super_block *sb, char *options, int is_vfat, 1020 int silent, int *debug, struct fat_mount_options *opts) 1021 { 1022 char *p; 1023 substring_t args[MAX_OPT_ARGS]; 1024 int option; 1025 char *iocharset; 1026 1027 opts->isvfat = is_vfat; 1028 1029 opts->fs_uid = current_uid(); 1030 opts->fs_gid = current_gid(); 1031 opts->fs_fmask = opts->fs_dmask = current_umask(); 1032 opts->allow_utime = -1; 1033 opts->codepage = fat_default_codepage; 1034 opts->iocharset = fat_default_iocharset; 1035 if (is_vfat) { 1036 opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95; 1037 opts->rodir = 0; 1038 } else { 1039 opts->shortname = 0; 1040 opts->rodir = 1; 1041 } 1042 opts->name_check = 'n'; 1043 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0; 1044 opts->utf8 = opts->unicode_xlate = 0; 1045 opts->numtail = 1; 1046 opts->usefree = opts->nocase = 0; 1047 opts->tz_set = 0; 1048 opts->nfs = 0; 1049 opts->errors = FAT_ERRORS_RO; 1050 *debug = 0; 1051 1052 if (!options) 1053 goto out; 1054 1055 while ((p = strsep(&options, ",")) != NULL) { 1056 int token; 1057 if (!*p) 1058 continue; 1059 1060 token = match_token(p, fat_tokens, args); 1061 if (token == Opt_err) { 1062 if (is_vfat) 1063 token = match_token(p, vfat_tokens, args); 1064 else 1065 token = match_token(p, msdos_tokens, args); 1066 } 1067 switch (token) { 1068 case Opt_check_s: 1069 opts->name_check = 's'; 1070 break; 1071 case Opt_check_r: 1072 opts->name_check = 'r'; 1073 break; 1074 case Opt_check_n: 1075 opts->name_check = 'n'; 1076 break; 1077 case Opt_usefree: 1078 opts->usefree = 1; 1079 break; 1080 case Opt_nocase: 1081 if (!is_vfat) 1082 opts->nocase = 1; 1083 else { 1084 /* for backward compatibility */ 1085 opts->shortname = VFAT_SFN_DISPLAY_WIN95 1086 | VFAT_SFN_CREATE_WIN95; 1087 } 1088 break; 1089 case Opt_quiet: 1090 opts->quiet = 1; 1091 break; 1092 case Opt_showexec: 1093 opts->showexec = 1; 1094 break; 1095 case Opt_debug: 1096 *debug = 1; 1097 break; 1098 case Opt_immutable: 1099 opts->sys_immutable = 1; 1100 break; 1101 case Opt_uid: 1102 if (match_int(&args[0], &option)) 1103 return -EINVAL; 1104 opts->fs_uid = make_kuid(current_user_ns(), option); 1105 if (!uid_valid(opts->fs_uid)) 1106 return -EINVAL; 1107 break; 1108 case Opt_gid: 1109 if (match_int(&args[0], &option)) 1110 return -EINVAL; 1111 opts->fs_gid = make_kgid(current_user_ns(), option); 1112 if (!gid_valid(opts->fs_gid)) 1113 return -EINVAL; 1114 break; 1115 case Opt_umask: 1116 if (match_octal(&args[0], &option)) 1117 return -EINVAL; 1118 opts->fs_fmask = opts->fs_dmask = option; 1119 break; 1120 case Opt_dmask: 1121 if (match_octal(&args[0], &option)) 1122 return -EINVAL; 1123 opts->fs_dmask = option; 1124 break; 1125 case Opt_fmask: 1126 if (match_octal(&args[0], &option)) 1127 return -EINVAL; 1128 opts->fs_fmask = option; 1129 break; 1130 case Opt_allow_utime: 1131 if (match_octal(&args[0], &option)) 1132 return -EINVAL; 1133 opts->allow_utime = option & (S_IWGRP | S_IWOTH); 1134 break; 1135 case Opt_codepage: 1136 if (match_int(&args[0], &option)) 1137 return -EINVAL; 1138 opts->codepage = option; 1139 break; 1140 case Opt_flush: 1141 opts->flush = 1; 1142 break; 1143 case Opt_time_offset: 1144 if (match_int(&args[0], &option)) 1145 return -EINVAL; 1146 if (option < -12 * 60 || option > 12 * 60) 1147 return -EINVAL; 1148 opts->tz_set = 1; 1149 opts->time_offset = option; 1150 break; 1151 case Opt_tz_utc: 1152 opts->tz_set = 1; 1153 opts->time_offset = 0; 1154 break; 1155 case Opt_err_cont: 1156 opts->errors = FAT_ERRORS_CONT; 1157 break; 1158 case Opt_err_panic: 1159 opts->errors = FAT_ERRORS_PANIC; 1160 break; 1161 case Opt_err_ro: 1162 opts->errors = FAT_ERRORS_RO; 1163 break; 1164 case Opt_nfs_stale_rw: 1165 opts->nfs = FAT_NFS_STALE_RW; 1166 break; 1167 case Opt_nfs_nostale_ro: 1168 opts->nfs = FAT_NFS_NOSTALE_RO; 1169 break; 1170 case Opt_dos1xfloppy: 1171 opts->dos1xfloppy = 1; 1172 break; 1173 1174 /* msdos specific */ 1175 case Opt_dots: 1176 opts->dotsOK = 1; 1177 break; 1178 case Opt_nodots: 1179 opts->dotsOK = 0; 1180 break; 1181 1182 /* vfat specific */ 1183 case Opt_charset: 1184 if (opts->iocharset != fat_default_iocharset) 1185 kfree(opts->iocharset); 1186 iocharset = match_strdup(&args[0]); 1187 if (!iocharset) 1188 return -ENOMEM; 1189 opts->iocharset = iocharset; 1190 break; 1191 case Opt_shortname_lower: 1192 opts->shortname = VFAT_SFN_DISPLAY_LOWER 1193 | VFAT_SFN_CREATE_WIN95; 1194 break; 1195 case Opt_shortname_win95: 1196 opts->shortname = VFAT_SFN_DISPLAY_WIN95 1197 | VFAT_SFN_CREATE_WIN95; 1198 break; 1199 case Opt_shortname_winnt: 1200 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1201 | VFAT_SFN_CREATE_WINNT; 1202 break; 1203 case Opt_shortname_mixed: 1204 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1205 | VFAT_SFN_CREATE_WIN95; 1206 break; 1207 case Opt_utf8_no: /* 0 or no or false */ 1208 opts->utf8 = 0; 1209 break; 1210 case Opt_utf8_yes: /* empty or 1 or yes or true */ 1211 opts->utf8 = 1; 1212 break; 1213 case Opt_uni_xl_no: /* 0 or no or false */ 1214 opts->unicode_xlate = 0; 1215 break; 1216 case Opt_uni_xl_yes: /* empty or 1 or yes or true */ 1217 opts->unicode_xlate = 1; 1218 break; 1219 case Opt_nonumtail_no: /* 0 or no or false */ 1220 opts->numtail = 1; /* negated option */ 1221 break; 1222 case Opt_nonumtail_yes: /* empty or 1 or yes or true */ 1223 opts->numtail = 0; /* negated option */ 1224 break; 1225 case Opt_rodir: 1226 opts->rodir = 1; 1227 break; 1228 case Opt_discard: 1229 opts->discard = 1; 1230 break; 1231 1232 /* obsolete mount options */ 1233 case Opt_obsolete: 1234 fat_msg(sb, KERN_INFO, "\"%s\" option is obsolete, " 1235 "not supported now", p); 1236 break; 1237 /* unknown option */ 1238 default: 1239 if (!silent) { 1240 fat_msg(sb, KERN_ERR, 1241 "Unrecognized mount option \"%s\" " 1242 "or missing value", p); 1243 } 1244 return -EINVAL; 1245 } 1246 } 1247 1248 out: 1249 /* UTF-8 doesn't provide FAT semantics */ 1250 if (!strcmp(opts->iocharset, "utf8")) { 1251 fat_msg(sb, KERN_WARNING, "utf8 is not a recommended IO charset" 1252 " for FAT filesystems, filesystem will be " 1253 "case sensitive!"); 1254 } 1255 1256 /* If user doesn't specify allow_utime, it's initialized from dmask. */ 1257 if (opts->allow_utime == (unsigned short)-1) 1258 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH); 1259 if (opts->unicode_xlate) 1260 opts->utf8 = 0; 1261 if (opts->nfs == FAT_NFS_NOSTALE_RO) { 1262 sb->s_flags |= MS_RDONLY; 1263 sb->s_export_op = &fat_export_ops_nostale; 1264 } 1265 1266 return 0; 1267 } 1268 1269 static int fat_read_root(struct inode *inode) 1270 { 1271 struct super_block *sb = inode->i_sb; 1272 struct msdos_sb_info *sbi = MSDOS_SB(sb); 1273 int error; 1274 1275 MSDOS_I(inode)->i_pos = MSDOS_ROOT_INO; 1276 inode->i_uid = sbi->options.fs_uid; 1277 inode->i_gid = sbi->options.fs_gid; 1278 inode->i_version++; 1279 inode->i_generation = 0; 1280 inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO); 1281 inode->i_op = sbi->dir_ops; 1282 inode->i_fop = &fat_dir_operations; 1283 if (sbi->fat_bits == 32) { 1284 MSDOS_I(inode)->i_start = sbi->root_cluster; 1285 error = fat_calc_dir_size(inode); 1286 if (error < 0) 1287 return error; 1288 } else { 1289 MSDOS_I(inode)->i_start = 0; 1290 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry); 1291 } 1292 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 1293 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 1294 MSDOS_I(inode)->i_logstart = 0; 1295 MSDOS_I(inode)->mmu_private = inode->i_size; 1296 1297 fat_save_attrs(inode, ATTR_DIR); 1298 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0; 1299 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0; 1300 set_nlink(inode, fat_subdirs(inode)+2); 1301 1302 return 0; 1303 } 1304 1305 static unsigned long calc_fat_clusters(struct super_block *sb) 1306 { 1307 struct msdos_sb_info *sbi = MSDOS_SB(sb); 1308 1309 /* Divide first to avoid overflow */ 1310 if (sbi->fat_bits != 12) { 1311 unsigned long ent_per_sec = sb->s_blocksize * 8 / sbi->fat_bits; 1312 return ent_per_sec * sbi->fat_length; 1313 } 1314 1315 return sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits; 1316 } 1317 1318 static bool fat_bpb_is_zero(struct fat_boot_sector *b) 1319 { 1320 if (get_unaligned_le16(&b->sector_size)) 1321 return false; 1322 if (b->sec_per_clus) 1323 return false; 1324 if (b->reserved) 1325 return false; 1326 if (b->fats) 1327 return false; 1328 if (get_unaligned_le16(&b->dir_entries)) 1329 return false; 1330 if (get_unaligned_le16(&b->sectors)) 1331 return false; 1332 if (b->media) 1333 return false; 1334 if (b->fat_length) 1335 return false; 1336 if (b->secs_track) 1337 return false; 1338 if (b->heads) 1339 return false; 1340 return true; 1341 } 1342 1343 static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b, 1344 int silent, struct fat_bios_param_block *bpb) 1345 { 1346 int error = -EINVAL; 1347 1348 /* Read in BPB ... */ 1349 memset(bpb, 0, sizeof(*bpb)); 1350 bpb->fat_sector_size = get_unaligned_le16(&b->sector_size); 1351 bpb->fat_sec_per_clus = b->sec_per_clus; 1352 bpb->fat_reserved = le16_to_cpu(b->reserved); 1353 bpb->fat_fats = b->fats; 1354 bpb->fat_dir_entries = get_unaligned_le16(&b->dir_entries); 1355 bpb->fat_sectors = get_unaligned_le16(&b->sectors); 1356 bpb->fat_fat_length = le16_to_cpu(b->fat_length); 1357 bpb->fat_total_sect = le32_to_cpu(b->total_sect); 1358 1359 bpb->fat16_state = b->fat16.state; 1360 bpb->fat16_vol_id = get_unaligned_le32(b->fat16.vol_id); 1361 1362 bpb->fat32_length = le32_to_cpu(b->fat32.length); 1363 bpb->fat32_root_cluster = le32_to_cpu(b->fat32.root_cluster); 1364 bpb->fat32_info_sector = le16_to_cpu(b->fat32.info_sector); 1365 bpb->fat32_state = b->fat32.state; 1366 bpb->fat32_vol_id = get_unaligned_le32(b->fat32.vol_id); 1367 1368 /* Validate this looks like a FAT filesystem BPB */ 1369 if (!bpb->fat_reserved) { 1370 if (!silent) 1371 fat_msg(sb, KERN_ERR, 1372 "bogus number of reserved sectors"); 1373 goto out; 1374 } 1375 if (!bpb->fat_fats) { 1376 if (!silent) 1377 fat_msg(sb, KERN_ERR, "bogus number of FAT structure"); 1378 goto out; 1379 } 1380 1381 /* 1382 * Earlier we checked here that b->secs_track and b->head are nonzero, 1383 * but it turns out valid FAT filesystems can have zero there. 1384 */ 1385 1386 if (!fat_valid_media(b->media)) { 1387 if (!silent) 1388 fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)", 1389 (unsigned)b->media); 1390 goto out; 1391 } 1392 1393 if (!is_power_of_2(bpb->fat_sector_size) 1394 || (bpb->fat_sector_size < 512) 1395 || (bpb->fat_sector_size > 4096)) { 1396 if (!silent) 1397 fat_msg(sb, KERN_ERR, "bogus logical sector size %u", 1398 (unsigned)bpb->fat_sector_size); 1399 goto out; 1400 } 1401 1402 if (!is_power_of_2(bpb->fat_sec_per_clus)) { 1403 if (!silent) 1404 fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u", 1405 (unsigned)bpb->fat_sec_per_clus); 1406 goto out; 1407 } 1408 1409 error = 0; 1410 1411 out: 1412 return error; 1413 } 1414 1415 static int fat_read_static_bpb(struct super_block *sb, 1416 struct fat_boot_sector *b, int silent, 1417 struct fat_bios_param_block *bpb) 1418 { 1419 static const char *notdos1x = "This doesn't look like a DOS 1.x volume"; 1420 1421 struct fat_floppy_defaults *fdefaults = NULL; 1422 int error = -EINVAL; 1423 sector_t bd_sects; 1424 unsigned i; 1425 1426 bd_sects = i_size_read(sb->s_bdev->bd_inode) / SECTOR_SIZE; 1427 1428 /* 16-bit DOS 1.x reliably wrote bootstrap short-jmp code */ 1429 if (b->ignored[0] != 0xeb || b->ignored[2] != 0x90) { 1430 if (!silent) 1431 fat_msg(sb, KERN_ERR, 1432 "%s; no bootstrapping code", notdos1x); 1433 goto out; 1434 } 1435 1436 /* 1437 * If any value in this region is non-zero, it isn't archaic 1438 * DOS. 1439 */ 1440 if (!fat_bpb_is_zero(b)) { 1441 if (!silent) 1442 fat_msg(sb, KERN_ERR, 1443 "%s; DOS 2.x BPB is non-zero", notdos1x); 1444 goto out; 1445 } 1446 1447 for (i = 0; i < ARRAY_SIZE(floppy_defaults); i++) { 1448 if (floppy_defaults[i].nr_sectors == bd_sects) { 1449 fdefaults = &floppy_defaults[i]; 1450 break; 1451 } 1452 } 1453 1454 if (fdefaults == NULL) { 1455 if (!silent) 1456 fat_msg(sb, KERN_WARNING, 1457 "This looks like a DOS 1.x volume, but isn't a recognized floppy size (%llu sectors)", 1458 (u64)bd_sects); 1459 goto out; 1460 } 1461 1462 if (!silent) 1463 fat_msg(sb, KERN_INFO, 1464 "This looks like a DOS 1.x volume; assuming default BPB values"); 1465 1466 memset(bpb, 0, sizeof(*bpb)); 1467 bpb->fat_sector_size = SECTOR_SIZE; 1468 bpb->fat_sec_per_clus = fdefaults->sec_per_clus; 1469 bpb->fat_reserved = 1; 1470 bpb->fat_fats = 2; 1471 bpb->fat_dir_entries = fdefaults->dir_entries; 1472 bpb->fat_sectors = fdefaults->nr_sectors; 1473 bpb->fat_fat_length = fdefaults->fat_length; 1474 1475 error = 0; 1476 1477 out: 1478 return error; 1479 } 1480 1481 /* 1482 * Read the super block of an MS-DOS FS. 1483 */ 1484 int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat, 1485 void (*setup)(struct super_block *)) 1486 { 1487 struct inode *root_inode = NULL, *fat_inode = NULL; 1488 struct inode *fsinfo_inode = NULL; 1489 struct buffer_head *bh; 1490 struct fat_bios_param_block bpb; 1491 struct msdos_sb_info *sbi; 1492 u16 logical_sector_size; 1493 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors; 1494 int debug; 1495 long error; 1496 char buf[50]; 1497 1498 /* 1499 * GFP_KERNEL is ok here, because while we do hold the 1500 * supeblock lock, memory pressure can't call back into 1501 * the filesystem, since we're only just about to mount 1502 * it and have no inodes etc active! 1503 */ 1504 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL); 1505 if (!sbi) 1506 return -ENOMEM; 1507 sb->s_fs_info = sbi; 1508 1509 sb->s_flags |= MS_NODIRATIME; 1510 sb->s_magic = MSDOS_SUPER_MAGIC; 1511 sb->s_op = &fat_sops; 1512 sb->s_export_op = &fat_export_ops; 1513 mutex_init(&sbi->nfs_build_inode_lock); 1514 ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL, 1515 DEFAULT_RATELIMIT_BURST); 1516 1517 error = parse_options(sb, data, isvfat, silent, &debug, &sbi->options); 1518 if (error) 1519 goto out_fail; 1520 1521 setup(sb); /* flavour-specific stuff that needs options */ 1522 1523 error = -EIO; 1524 sb_min_blocksize(sb, 512); 1525 bh = sb_bread(sb, 0); 1526 if (bh == NULL) { 1527 fat_msg(sb, KERN_ERR, "unable to read boot sector"); 1528 goto out_fail; 1529 } 1530 1531 error = fat_read_bpb(sb, (struct fat_boot_sector *)bh->b_data, silent, 1532 &bpb); 1533 if (error == -EINVAL && sbi->options.dos1xfloppy) 1534 error = fat_read_static_bpb(sb, 1535 (struct fat_boot_sector *)bh->b_data, silent, &bpb); 1536 brelse(bh); 1537 1538 if (error == -EINVAL) 1539 goto out_invalid; 1540 else if (error) 1541 goto out_fail; 1542 1543 logical_sector_size = bpb.fat_sector_size; 1544 sbi->sec_per_clus = bpb.fat_sec_per_clus; 1545 1546 error = -EIO; 1547 if (logical_sector_size < sb->s_blocksize) { 1548 fat_msg(sb, KERN_ERR, "logical sector size too small for device" 1549 " (logical sector size = %u)", logical_sector_size); 1550 goto out_fail; 1551 } 1552 1553 if (logical_sector_size > sb->s_blocksize) { 1554 struct buffer_head *bh_resize; 1555 1556 if (!sb_set_blocksize(sb, logical_sector_size)) { 1557 fat_msg(sb, KERN_ERR, "unable to set blocksize %u", 1558 logical_sector_size); 1559 goto out_fail; 1560 } 1561 1562 /* Verify that the larger boot sector is fully readable */ 1563 bh_resize = sb_bread(sb, 0); 1564 if (bh_resize == NULL) { 1565 fat_msg(sb, KERN_ERR, "unable to read boot sector" 1566 " (logical sector size = %lu)", 1567 sb->s_blocksize); 1568 goto out_fail; 1569 } 1570 brelse(bh_resize); 1571 } 1572 1573 mutex_init(&sbi->s_lock); 1574 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus; 1575 sbi->cluster_bits = ffs(sbi->cluster_size) - 1; 1576 sbi->fats = bpb.fat_fats; 1577 sbi->fat_bits = 0; /* Don't know yet */ 1578 sbi->fat_start = bpb.fat_reserved; 1579 sbi->fat_length = bpb.fat_fat_length; 1580 sbi->root_cluster = 0; 1581 sbi->free_clusters = -1; /* Don't know yet */ 1582 sbi->free_clus_valid = 0; 1583 sbi->prev_free = FAT_START_ENT; 1584 sb->s_maxbytes = 0xffffffff; 1585 1586 if (!sbi->fat_length && bpb.fat32_length) { 1587 struct fat_boot_fsinfo *fsinfo; 1588 struct buffer_head *fsinfo_bh; 1589 1590 /* Must be FAT32 */ 1591 sbi->fat_bits = 32; 1592 sbi->fat_length = bpb.fat32_length; 1593 sbi->root_cluster = bpb.fat32_root_cluster; 1594 1595 /* MC - if info_sector is 0, don't multiply by 0 */ 1596 sbi->fsinfo_sector = bpb.fat32_info_sector; 1597 if (sbi->fsinfo_sector == 0) 1598 sbi->fsinfo_sector = 1; 1599 1600 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector); 1601 if (fsinfo_bh == NULL) { 1602 fat_msg(sb, KERN_ERR, "bread failed, FSINFO block" 1603 " (sector = %lu)", sbi->fsinfo_sector); 1604 goto out_fail; 1605 } 1606 1607 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data; 1608 if (!IS_FSINFO(fsinfo)) { 1609 fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: " 1610 "0x%08x, 0x%08x (sector = %lu)", 1611 le32_to_cpu(fsinfo->signature1), 1612 le32_to_cpu(fsinfo->signature2), 1613 sbi->fsinfo_sector); 1614 } else { 1615 if (sbi->options.usefree) 1616 sbi->free_clus_valid = 1; 1617 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters); 1618 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster); 1619 } 1620 1621 brelse(fsinfo_bh); 1622 } 1623 1624 /* interpret volume ID as a little endian 32 bit integer */ 1625 if (sbi->fat_bits == 32) 1626 sbi->vol_id = bpb.fat32_vol_id; 1627 else /* fat 16 or 12 */ 1628 sbi->vol_id = bpb.fat16_vol_id; 1629 1630 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry); 1631 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1; 1632 1633 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length; 1634 sbi->dir_entries = bpb.fat_dir_entries; 1635 if (sbi->dir_entries & (sbi->dir_per_block - 1)) { 1636 if (!silent) 1637 fat_msg(sb, KERN_ERR, "bogus directory-entries per block" 1638 " (%u)", sbi->dir_entries); 1639 goto out_invalid; 1640 } 1641 1642 rootdir_sectors = sbi->dir_entries 1643 * sizeof(struct msdos_dir_entry) / sb->s_blocksize; 1644 sbi->data_start = sbi->dir_start + rootdir_sectors; 1645 total_sectors = bpb.fat_sectors; 1646 if (total_sectors == 0) 1647 total_sectors = bpb.fat_total_sect; 1648 1649 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus; 1650 1651 if (sbi->fat_bits != 32) 1652 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12; 1653 1654 /* some OSes set FAT_STATE_DIRTY and clean it on unmount. */ 1655 if (sbi->fat_bits == 32) 1656 sbi->dirty = bpb.fat32_state & FAT_STATE_DIRTY; 1657 else /* fat 16 or 12 */ 1658 sbi->dirty = bpb.fat16_state & FAT_STATE_DIRTY; 1659 1660 /* check that FAT table does not overflow */ 1661 fat_clusters = calc_fat_clusters(sb); 1662 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT); 1663 if (total_clusters > MAX_FAT(sb)) { 1664 if (!silent) 1665 fat_msg(sb, KERN_ERR, "count of clusters too big (%u)", 1666 total_clusters); 1667 goto out_invalid; 1668 } 1669 1670 sbi->max_cluster = total_clusters + FAT_START_ENT; 1671 /* check the free_clusters, it's not necessarily correct */ 1672 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters) 1673 sbi->free_clusters = -1; 1674 /* check the prev_free, it's not necessarily correct */ 1675 sbi->prev_free %= sbi->max_cluster; 1676 if (sbi->prev_free < FAT_START_ENT) 1677 sbi->prev_free = FAT_START_ENT; 1678 1679 /* set up enough so that it can read an inode */ 1680 fat_hash_init(sb); 1681 dir_hash_init(sb); 1682 fat_ent_access_init(sb); 1683 1684 /* 1685 * The low byte of FAT's first entry must have same value with 1686 * media-field. But in real world, too many devices is 1687 * writing wrong value. So, removed that validity check. 1688 * 1689 * if (FAT_FIRST_ENT(sb, media) != first) 1690 */ 1691 1692 error = -EINVAL; 1693 sprintf(buf, "cp%d", sbi->options.codepage); 1694 sbi->nls_disk = load_nls(buf); 1695 if (!sbi->nls_disk) { 1696 fat_msg(sb, KERN_ERR, "codepage %s not found", buf); 1697 goto out_fail; 1698 } 1699 1700 /* FIXME: utf8 is using iocharset for upper/lower conversion */ 1701 if (sbi->options.isvfat) { 1702 sbi->nls_io = load_nls(sbi->options.iocharset); 1703 if (!sbi->nls_io) { 1704 fat_msg(sb, KERN_ERR, "IO charset %s not found", 1705 sbi->options.iocharset); 1706 goto out_fail; 1707 } 1708 } 1709 1710 error = -ENOMEM; 1711 fat_inode = new_inode(sb); 1712 if (!fat_inode) 1713 goto out_fail; 1714 MSDOS_I(fat_inode)->i_pos = 0; 1715 sbi->fat_inode = fat_inode; 1716 1717 fsinfo_inode = new_inode(sb); 1718 if (!fsinfo_inode) 1719 goto out_fail; 1720 fsinfo_inode->i_ino = MSDOS_FSINFO_INO; 1721 sbi->fsinfo_inode = fsinfo_inode; 1722 insert_inode_hash(fsinfo_inode); 1723 1724 root_inode = new_inode(sb); 1725 if (!root_inode) 1726 goto out_fail; 1727 root_inode->i_ino = MSDOS_ROOT_INO; 1728 root_inode->i_version = 1; 1729 error = fat_read_root(root_inode); 1730 if (error < 0) { 1731 iput(root_inode); 1732 goto out_fail; 1733 } 1734 error = -ENOMEM; 1735 insert_inode_hash(root_inode); 1736 fat_attach(root_inode, 0); 1737 sb->s_root = d_make_root(root_inode); 1738 if (!sb->s_root) { 1739 fat_msg(sb, KERN_ERR, "get root inode failed"); 1740 goto out_fail; 1741 } 1742 1743 if (sbi->options.discard) { 1744 struct request_queue *q = bdev_get_queue(sb->s_bdev); 1745 if (!blk_queue_discard(q)) 1746 fat_msg(sb, KERN_WARNING, 1747 "mounting with \"discard\" option, but " 1748 "the device does not support discard"); 1749 } 1750 1751 fat_set_state(sb, 1, 0); 1752 return 0; 1753 1754 out_invalid: 1755 error = -EINVAL; 1756 if (!silent) 1757 fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem"); 1758 1759 out_fail: 1760 if (fsinfo_inode) 1761 iput(fsinfo_inode); 1762 if (fat_inode) 1763 iput(fat_inode); 1764 unload_nls(sbi->nls_io); 1765 unload_nls(sbi->nls_disk); 1766 if (sbi->options.iocharset != fat_default_iocharset) 1767 kfree(sbi->options.iocharset); 1768 sb->s_fs_info = NULL; 1769 kfree(sbi); 1770 return error; 1771 } 1772 1773 EXPORT_SYMBOL_GPL(fat_fill_super); 1774 1775 /* 1776 * helper function for fat_flush_inodes. This writes both the inode 1777 * and the file data blocks, waiting for in flight data blocks before 1778 * the start of the call. It does not wait for any io started 1779 * during the call 1780 */ 1781 static int writeback_inode(struct inode *inode) 1782 { 1783 1784 int ret; 1785 1786 /* if we used wait=1, sync_inode_metadata waits for the io for the 1787 * inode to finish. So wait=0 is sent down to sync_inode_metadata 1788 * and filemap_fdatawrite is used for the data blocks 1789 */ 1790 ret = sync_inode_metadata(inode, 0); 1791 if (!ret) 1792 ret = filemap_fdatawrite(inode->i_mapping); 1793 return ret; 1794 } 1795 1796 /* 1797 * write data and metadata corresponding to i1 and i2. The io is 1798 * started but we do not wait for any of it to finish. 1799 * 1800 * filemap_flush is used for the block device, so if there is a dirty 1801 * page for a block already in flight, we will not wait and start the 1802 * io over again 1803 */ 1804 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2) 1805 { 1806 int ret = 0; 1807 if (!MSDOS_SB(sb)->options.flush) 1808 return 0; 1809 if (i1) 1810 ret = writeback_inode(i1); 1811 if (!ret && i2) 1812 ret = writeback_inode(i2); 1813 if (!ret) { 1814 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping; 1815 ret = filemap_flush(mapping); 1816 } 1817 return ret; 1818 } 1819 EXPORT_SYMBOL_GPL(fat_flush_inodes); 1820 1821 static int __init init_fat_fs(void) 1822 { 1823 int err; 1824 1825 err = fat_cache_init(); 1826 if (err) 1827 return err; 1828 1829 err = fat_init_inodecache(); 1830 if (err) 1831 goto failed; 1832 1833 return 0; 1834 1835 failed: 1836 fat_cache_destroy(); 1837 return err; 1838 } 1839 1840 static void __exit exit_fat_fs(void) 1841 { 1842 fat_cache_destroy(); 1843 fat_destroy_inodecache(); 1844 } 1845 1846 module_init(init_fat_fs) 1847 module_exit(exit_fat_fs) 1848 1849 MODULE_LICENSE("GPL"); 1850