1 /* 2 * linux/fs/fat/inode.c 3 * 4 * Written 1992,1993 by Werner Almesberger 5 * VFAT extensions by Gordon Chaffee, merged with msdos fs by Henrik Storner 6 * Rewritten for the constant inumbers support by Al Viro 7 * 8 * Fixes: 9 * 10 * Max Cohan: Fixed invalid FSINFO offset when info_sector is 0 11 */ 12 13 #include <linux/module.h> 14 #include <linux/init.h> 15 #include <linux/time.h> 16 #include <linux/slab.h> 17 #include <linux/seq_file.h> 18 #include <linux/pagemap.h> 19 #include <linux/mpage.h> 20 #include <linux/buffer_head.h> 21 #include <linux/exportfs.h> 22 #include <linux/mount.h> 23 #include <linux/vfs.h> 24 #include <linux/parser.h> 25 #include <linux/uio.h> 26 #include <linux/writeback.h> 27 #include <linux/log2.h> 28 #include <linux/hash.h> 29 #include <asm/unaligned.h> 30 #include "fat.h" 31 32 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET 33 /* if user don't select VFAT, this is undefined. */ 34 #define CONFIG_FAT_DEFAULT_IOCHARSET "" 35 #endif 36 37 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE; 38 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET; 39 40 41 static int fat_add_cluster(struct inode *inode) 42 { 43 int err, cluster; 44 45 err = fat_alloc_clusters(inode, &cluster, 1); 46 if (err) 47 return err; 48 /* FIXME: this cluster should be added after data of this 49 * cluster is writed */ 50 err = fat_chain_add(inode, cluster, 1); 51 if (err) 52 fat_free_clusters(inode, cluster); 53 return err; 54 } 55 56 static inline int __fat_get_block(struct inode *inode, sector_t iblock, 57 unsigned long *max_blocks, 58 struct buffer_head *bh_result, int create) 59 { 60 struct super_block *sb = inode->i_sb; 61 struct msdos_sb_info *sbi = MSDOS_SB(sb); 62 unsigned long mapped_blocks; 63 sector_t phys; 64 int err, offset; 65 66 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create); 67 if (err) 68 return err; 69 if (phys) { 70 map_bh(bh_result, sb, phys); 71 *max_blocks = min(mapped_blocks, *max_blocks); 72 return 0; 73 } 74 if (!create) 75 return 0; 76 77 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) { 78 fat_fs_error(sb, "corrupted file size (i_pos %lld, %lld)", 79 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private); 80 return -EIO; 81 } 82 83 offset = (unsigned long)iblock & (sbi->sec_per_clus - 1); 84 if (!offset) { 85 /* TODO: multiple cluster allocation would be desirable. */ 86 err = fat_add_cluster(inode); 87 if (err) 88 return err; 89 } 90 /* available blocks on this cluster */ 91 mapped_blocks = sbi->sec_per_clus - offset; 92 93 *max_blocks = min(mapped_blocks, *max_blocks); 94 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits; 95 96 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create); 97 if (err) 98 return err; 99 100 BUG_ON(!phys); 101 BUG_ON(*max_blocks != mapped_blocks); 102 set_buffer_new(bh_result); 103 map_bh(bh_result, sb, phys); 104 105 return 0; 106 } 107 108 static int fat_get_block(struct inode *inode, sector_t iblock, 109 struct buffer_head *bh_result, int create) 110 { 111 struct super_block *sb = inode->i_sb; 112 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits; 113 int err; 114 115 err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create); 116 if (err) 117 return err; 118 bh_result->b_size = max_blocks << sb->s_blocksize_bits; 119 return 0; 120 } 121 122 static int fat_writepage(struct page *page, struct writeback_control *wbc) 123 { 124 return block_write_full_page(page, fat_get_block, wbc); 125 } 126 127 static int fat_writepages(struct address_space *mapping, 128 struct writeback_control *wbc) 129 { 130 return mpage_writepages(mapping, wbc, fat_get_block); 131 } 132 133 static int fat_readpage(struct file *file, struct page *page) 134 { 135 return mpage_readpage(page, fat_get_block); 136 } 137 138 static int fat_readpages(struct file *file, struct address_space *mapping, 139 struct list_head *pages, unsigned nr_pages) 140 { 141 return mpage_readpages(mapping, pages, nr_pages, fat_get_block); 142 } 143 144 static void fat_write_failed(struct address_space *mapping, loff_t to) 145 { 146 struct inode *inode = mapping->host; 147 148 if (to > inode->i_size) { 149 truncate_pagecache(inode, to, inode->i_size); 150 fat_truncate_blocks(inode, inode->i_size); 151 } 152 } 153 154 static int fat_write_begin(struct file *file, struct address_space *mapping, 155 loff_t pos, unsigned len, unsigned flags, 156 struct page **pagep, void **fsdata) 157 { 158 int err; 159 160 *pagep = NULL; 161 err = cont_write_begin(file, mapping, pos, len, flags, 162 pagep, fsdata, fat_get_block, 163 &MSDOS_I(mapping->host)->mmu_private); 164 if (err < 0) 165 fat_write_failed(mapping, pos + len); 166 return err; 167 } 168 169 static int fat_write_end(struct file *file, struct address_space *mapping, 170 loff_t pos, unsigned len, unsigned copied, 171 struct page *pagep, void *fsdata) 172 { 173 struct inode *inode = mapping->host; 174 int err; 175 err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata); 176 if (err < len) 177 fat_write_failed(mapping, pos + len); 178 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) { 179 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC; 180 MSDOS_I(inode)->i_attrs |= ATTR_ARCH; 181 mark_inode_dirty(inode); 182 } 183 return err; 184 } 185 186 static ssize_t fat_direct_IO(int rw, struct kiocb *iocb, 187 const struct iovec *iov, 188 loff_t offset, unsigned long nr_segs) 189 { 190 struct file *file = iocb->ki_filp; 191 struct address_space *mapping = file->f_mapping; 192 struct inode *inode = mapping->host; 193 ssize_t ret; 194 195 if (rw == WRITE) { 196 /* 197 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(), 198 * so we need to update the ->mmu_private to block boundary. 199 * 200 * But we must fill the remaining area or hole by nul for 201 * updating ->mmu_private. 202 * 203 * Return 0, and fallback to normal buffered write. 204 */ 205 loff_t size = offset + iov_length(iov, nr_segs); 206 if (MSDOS_I(inode)->mmu_private < size) 207 return 0; 208 } 209 210 /* 211 * FAT need to use the DIO_LOCKING for avoiding the race 212 * condition of fat_get_block() and ->truncate(). 213 */ 214 ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, 215 iov, offset, nr_segs, fat_get_block, NULL); 216 if (ret < 0 && (rw & WRITE)) 217 fat_write_failed(mapping, offset + iov_length(iov, nr_segs)); 218 219 return ret; 220 } 221 222 static sector_t _fat_bmap(struct address_space *mapping, sector_t block) 223 { 224 sector_t blocknr; 225 226 /* fat_get_cluster() assumes the requested blocknr isn't truncated. */ 227 down_read(&mapping->host->i_alloc_sem); 228 blocknr = generic_block_bmap(mapping, block, fat_get_block); 229 up_read(&mapping->host->i_alloc_sem); 230 231 return blocknr; 232 } 233 234 static const struct address_space_operations fat_aops = { 235 .readpage = fat_readpage, 236 .readpages = fat_readpages, 237 .writepage = fat_writepage, 238 .writepages = fat_writepages, 239 .sync_page = block_sync_page, 240 .write_begin = fat_write_begin, 241 .write_end = fat_write_end, 242 .direct_IO = fat_direct_IO, 243 .bmap = _fat_bmap 244 }; 245 246 /* 247 * New FAT inode stuff. We do the following: 248 * a) i_ino is constant and has nothing with on-disk location. 249 * b) FAT manages its own cache of directory entries. 250 * c) *This* cache is indexed by on-disk location. 251 * d) inode has an associated directory entry, all right, but 252 * it may be unhashed. 253 * e) currently entries are stored within struct inode. That should 254 * change. 255 * f) we deal with races in the following way: 256 * 1. readdir() and lookup() do FAT-dir-cache lookup. 257 * 2. rename() unhashes the F-d-c entry and rehashes it in 258 * a new place. 259 * 3. unlink() and rmdir() unhash F-d-c entry. 260 * 4. fat_write_inode() checks whether the thing is unhashed. 261 * If it is we silently return. If it isn't we do bread(), 262 * check if the location is still valid and retry if it 263 * isn't. Otherwise we do changes. 264 * 5. Spinlock is used to protect hash/unhash/location check/lookup 265 * 6. fat_evict_inode() unhashes the F-d-c entry. 266 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry 267 * and consider negative result as cache miss. 268 */ 269 270 static void fat_hash_init(struct super_block *sb) 271 { 272 struct msdos_sb_info *sbi = MSDOS_SB(sb); 273 int i; 274 275 spin_lock_init(&sbi->inode_hash_lock); 276 for (i = 0; i < FAT_HASH_SIZE; i++) 277 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]); 278 } 279 280 static inline unsigned long fat_hash(loff_t i_pos) 281 { 282 return hash_32(i_pos, FAT_HASH_BITS); 283 } 284 285 void fat_attach(struct inode *inode, loff_t i_pos) 286 { 287 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 288 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos); 289 290 spin_lock(&sbi->inode_hash_lock); 291 MSDOS_I(inode)->i_pos = i_pos; 292 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head); 293 spin_unlock(&sbi->inode_hash_lock); 294 } 295 EXPORT_SYMBOL_GPL(fat_attach); 296 297 void fat_detach(struct inode *inode) 298 { 299 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 300 spin_lock(&sbi->inode_hash_lock); 301 MSDOS_I(inode)->i_pos = 0; 302 hlist_del_init(&MSDOS_I(inode)->i_fat_hash); 303 spin_unlock(&sbi->inode_hash_lock); 304 } 305 EXPORT_SYMBOL_GPL(fat_detach); 306 307 struct inode *fat_iget(struct super_block *sb, loff_t i_pos) 308 { 309 struct msdos_sb_info *sbi = MSDOS_SB(sb); 310 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos); 311 struct hlist_node *_p; 312 struct msdos_inode_info *i; 313 struct inode *inode = NULL; 314 315 spin_lock(&sbi->inode_hash_lock); 316 hlist_for_each_entry(i, _p, head, i_fat_hash) { 317 BUG_ON(i->vfs_inode.i_sb != sb); 318 if (i->i_pos != i_pos) 319 continue; 320 inode = igrab(&i->vfs_inode); 321 if (inode) 322 break; 323 } 324 spin_unlock(&sbi->inode_hash_lock); 325 return inode; 326 } 327 328 static int is_exec(unsigned char *extension) 329 { 330 unsigned char *exe_extensions = "EXECOMBAT", *walk; 331 332 for (walk = exe_extensions; *walk; walk += 3) 333 if (!strncmp(extension, walk, 3)) 334 return 1; 335 return 0; 336 } 337 338 static int fat_calc_dir_size(struct inode *inode) 339 { 340 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 341 int ret, fclus, dclus; 342 343 inode->i_size = 0; 344 if (MSDOS_I(inode)->i_start == 0) 345 return 0; 346 347 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); 348 if (ret < 0) 349 return ret; 350 inode->i_size = (fclus + 1) << sbi->cluster_bits; 351 352 return 0; 353 } 354 355 /* doesn't deal with root inode */ 356 static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de) 357 { 358 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 359 int error; 360 361 MSDOS_I(inode)->i_pos = 0; 362 inode->i_uid = sbi->options.fs_uid; 363 inode->i_gid = sbi->options.fs_gid; 364 inode->i_version++; 365 inode->i_generation = get_seconds(); 366 367 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) { 368 inode->i_generation &= ~1; 369 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO); 370 inode->i_op = sbi->dir_ops; 371 inode->i_fop = &fat_dir_operations; 372 373 MSDOS_I(inode)->i_start = le16_to_cpu(de->start); 374 if (sbi->fat_bits == 32) 375 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16); 376 377 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 378 error = fat_calc_dir_size(inode); 379 if (error < 0) 380 return error; 381 MSDOS_I(inode)->mmu_private = inode->i_size; 382 383 inode->i_nlink = fat_subdirs(inode); 384 } else { /* not a directory */ 385 inode->i_generation |= 1; 386 inode->i_mode = fat_make_mode(sbi, de->attr, 387 ((sbi->options.showexec && !is_exec(de->name + 8)) 388 ? S_IRUGO|S_IWUGO : S_IRWXUGO)); 389 MSDOS_I(inode)->i_start = le16_to_cpu(de->start); 390 if (sbi->fat_bits == 32) 391 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16); 392 393 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 394 inode->i_size = le32_to_cpu(de->size); 395 inode->i_op = &fat_file_inode_operations; 396 inode->i_fop = &fat_file_operations; 397 inode->i_mapping->a_ops = &fat_aops; 398 MSDOS_I(inode)->mmu_private = inode->i_size; 399 } 400 if (de->attr & ATTR_SYS) { 401 if (sbi->options.sys_immutable) 402 inode->i_flags |= S_IMMUTABLE; 403 } 404 fat_save_attrs(inode, de->attr); 405 406 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 407 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 408 409 fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0); 410 if (sbi->options.isvfat) { 411 fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime, 412 de->cdate, de->ctime_cs); 413 fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0); 414 } else 415 inode->i_ctime = inode->i_atime = inode->i_mtime; 416 417 return 0; 418 } 419 420 struct inode *fat_build_inode(struct super_block *sb, 421 struct msdos_dir_entry *de, loff_t i_pos) 422 { 423 struct inode *inode; 424 int err; 425 426 inode = fat_iget(sb, i_pos); 427 if (inode) 428 goto out; 429 inode = new_inode(sb); 430 if (!inode) { 431 inode = ERR_PTR(-ENOMEM); 432 goto out; 433 } 434 inode->i_ino = iunique(sb, MSDOS_ROOT_INO); 435 inode->i_version = 1; 436 err = fat_fill_inode(inode, de); 437 if (err) { 438 iput(inode); 439 inode = ERR_PTR(err); 440 goto out; 441 } 442 fat_attach(inode, i_pos); 443 insert_inode_hash(inode); 444 out: 445 return inode; 446 } 447 448 EXPORT_SYMBOL_GPL(fat_build_inode); 449 450 static void fat_evict_inode(struct inode *inode) 451 { 452 truncate_inode_pages(&inode->i_data, 0); 453 if (!inode->i_nlink) { 454 inode->i_size = 0; 455 fat_truncate_blocks(inode, 0); 456 } 457 invalidate_inode_buffers(inode); 458 end_writeback(inode); 459 fat_cache_inval_inode(inode); 460 fat_detach(inode); 461 } 462 463 static void fat_write_super(struct super_block *sb) 464 { 465 lock_super(sb); 466 sb->s_dirt = 0; 467 468 if (!(sb->s_flags & MS_RDONLY)) 469 fat_clusters_flush(sb); 470 unlock_super(sb); 471 } 472 473 static int fat_sync_fs(struct super_block *sb, int wait) 474 { 475 int err = 0; 476 477 if (sb->s_dirt) { 478 lock_super(sb); 479 sb->s_dirt = 0; 480 err = fat_clusters_flush(sb); 481 unlock_super(sb); 482 } 483 484 return err; 485 } 486 487 static void fat_put_super(struct super_block *sb) 488 { 489 struct msdos_sb_info *sbi = MSDOS_SB(sb); 490 491 if (sb->s_dirt) 492 fat_write_super(sb); 493 494 iput(sbi->fat_inode); 495 496 unload_nls(sbi->nls_disk); 497 unload_nls(sbi->nls_io); 498 499 if (sbi->options.iocharset != fat_default_iocharset) 500 kfree(sbi->options.iocharset); 501 502 sb->s_fs_info = NULL; 503 kfree(sbi); 504 } 505 506 static struct kmem_cache *fat_inode_cachep; 507 508 static struct inode *fat_alloc_inode(struct super_block *sb) 509 { 510 struct msdos_inode_info *ei; 511 ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS); 512 if (!ei) 513 return NULL; 514 return &ei->vfs_inode; 515 } 516 517 static void fat_destroy_inode(struct inode *inode) 518 { 519 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode)); 520 } 521 522 static void init_once(void *foo) 523 { 524 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo; 525 526 spin_lock_init(&ei->cache_lru_lock); 527 ei->nr_caches = 0; 528 ei->cache_valid_id = FAT_CACHE_VALID + 1; 529 INIT_LIST_HEAD(&ei->cache_lru); 530 INIT_HLIST_NODE(&ei->i_fat_hash); 531 inode_init_once(&ei->vfs_inode); 532 } 533 534 static int __init fat_init_inodecache(void) 535 { 536 fat_inode_cachep = kmem_cache_create("fat_inode_cache", 537 sizeof(struct msdos_inode_info), 538 0, (SLAB_RECLAIM_ACCOUNT| 539 SLAB_MEM_SPREAD), 540 init_once); 541 if (fat_inode_cachep == NULL) 542 return -ENOMEM; 543 return 0; 544 } 545 546 static void __exit fat_destroy_inodecache(void) 547 { 548 kmem_cache_destroy(fat_inode_cachep); 549 } 550 551 static int fat_remount(struct super_block *sb, int *flags, char *data) 552 { 553 struct msdos_sb_info *sbi = MSDOS_SB(sb); 554 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME); 555 return 0; 556 } 557 558 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf) 559 { 560 struct super_block *sb = dentry->d_sb; 561 struct msdos_sb_info *sbi = MSDOS_SB(sb); 562 u64 id = huge_encode_dev(sb->s_bdev->bd_dev); 563 564 /* If the count of free cluster is still unknown, counts it here. */ 565 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) { 566 int err = fat_count_free_clusters(dentry->d_sb); 567 if (err) 568 return err; 569 } 570 571 buf->f_type = dentry->d_sb->s_magic; 572 buf->f_bsize = sbi->cluster_size; 573 buf->f_blocks = sbi->max_cluster - FAT_START_ENT; 574 buf->f_bfree = sbi->free_clusters; 575 buf->f_bavail = sbi->free_clusters; 576 buf->f_fsid.val[0] = (u32)id; 577 buf->f_fsid.val[1] = (u32)(id >> 32); 578 buf->f_namelen = sbi->options.isvfat ? FAT_LFN_LEN : 12; 579 580 return 0; 581 } 582 583 static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi, 584 struct inode *inode) 585 { 586 loff_t i_pos; 587 #if BITS_PER_LONG == 32 588 spin_lock(&sbi->inode_hash_lock); 589 #endif 590 i_pos = MSDOS_I(inode)->i_pos; 591 #if BITS_PER_LONG == 32 592 spin_unlock(&sbi->inode_hash_lock); 593 #endif 594 return i_pos; 595 } 596 597 static int __fat_write_inode(struct inode *inode, int wait) 598 { 599 struct super_block *sb = inode->i_sb; 600 struct msdos_sb_info *sbi = MSDOS_SB(sb); 601 struct buffer_head *bh; 602 struct msdos_dir_entry *raw_entry; 603 loff_t i_pos; 604 int err; 605 606 if (inode->i_ino == MSDOS_ROOT_INO) 607 return 0; 608 609 retry: 610 i_pos = fat_i_pos_read(sbi, inode); 611 if (!i_pos) 612 return 0; 613 614 bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits); 615 if (!bh) { 616 printk(KERN_ERR "FAT: unable to read inode block " 617 "for updating (i_pos %lld)\n", i_pos); 618 return -EIO; 619 } 620 spin_lock(&sbi->inode_hash_lock); 621 if (i_pos != MSDOS_I(inode)->i_pos) { 622 spin_unlock(&sbi->inode_hash_lock); 623 brelse(bh); 624 goto retry; 625 } 626 627 raw_entry = &((struct msdos_dir_entry *) (bh->b_data)) 628 [i_pos & (sbi->dir_per_block - 1)]; 629 if (S_ISDIR(inode->i_mode)) 630 raw_entry->size = 0; 631 else 632 raw_entry->size = cpu_to_le32(inode->i_size); 633 raw_entry->attr = fat_make_attrs(inode); 634 raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart); 635 raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16); 636 fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time, 637 &raw_entry->date, NULL); 638 if (sbi->options.isvfat) { 639 __le16 atime; 640 fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime, 641 &raw_entry->cdate, &raw_entry->ctime_cs); 642 fat_time_unix2fat(sbi, &inode->i_atime, &atime, 643 &raw_entry->adate, NULL); 644 } 645 spin_unlock(&sbi->inode_hash_lock); 646 mark_buffer_dirty(bh); 647 err = 0; 648 if (wait) 649 err = sync_dirty_buffer(bh); 650 brelse(bh); 651 return err; 652 } 653 654 static int fat_write_inode(struct inode *inode, struct writeback_control *wbc) 655 { 656 return __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL); 657 } 658 659 int fat_sync_inode(struct inode *inode) 660 { 661 return __fat_write_inode(inode, 1); 662 } 663 664 EXPORT_SYMBOL_GPL(fat_sync_inode); 665 666 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt); 667 static const struct super_operations fat_sops = { 668 .alloc_inode = fat_alloc_inode, 669 .destroy_inode = fat_destroy_inode, 670 .write_inode = fat_write_inode, 671 .evict_inode = fat_evict_inode, 672 .put_super = fat_put_super, 673 .write_super = fat_write_super, 674 .sync_fs = fat_sync_fs, 675 .statfs = fat_statfs, 676 .remount_fs = fat_remount, 677 678 .show_options = fat_show_options, 679 }; 680 681 /* 682 * a FAT file handle with fhtype 3 is 683 * 0/ i_ino - for fast, reliable lookup if still in the cache 684 * 1/ i_generation - to see if i_ino is still valid 685 * bit 0 == 0 iff directory 686 * 2/ i_pos(8-39) - if ino has changed, but still in cache 687 * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos 688 * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc 689 * 690 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum 691 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits 692 * of i_logstart is used to store the directory entry offset. 693 */ 694 695 static struct dentry *fat_fh_to_dentry(struct super_block *sb, 696 struct fid *fid, int fh_len, int fh_type) 697 { 698 struct inode *inode = NULL; 699 struct dentry *result; 700 u32 *fh = fid->raw; 701 702 if (fh_len < 5 || fh_type != 3) 703 return NULL; 704 705 inode = ilookup(sb, fh[0]); 706 if (!inode || inode->i_generation != fh[1]) { 707 if (inode) 708 iput(inode); 709 inode = NULL; 710 } 711 if (!inode) { 712 loff_t i_pos; 713 int i_logstart = fh[3] & 0x0fffffff; 714 715 i_pos = (loff_t)fh[2] << 8; 716 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28); 717 718 /* try 2 - see if i_pos is in F-d-c 719 * require i_logstart to be the same 720 * Will fail if you truncate and then re-write 721 */ 722 723 inode = fat_iget(sb, i_pos); 724 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) { 725 iput(inode); 726 inode = NULL; 727 } 728 } 729 730 /* 731 * For now, do nothing if the inode is not found. 732 * 733 * What we could do is: 734 * 735 * - follow the file starting at fh[4], and record the ".." entry, 736 * and the name of the fh[2] entry. 737 * - then follow the ".." file finding the next step up. 738 * 739 * This way we build a path to the root of the tree. If this works, we 740 * lookup the path and so get this inode into the cache. Finally try 741 * the fat_iget lookup again. If that fails, then we are totally out 742 * of luck. But all that is for another day 743 */ 744 result = d_obtain_alias(inode); 745 if (!IS_ERR(result)) 746 result->d_op = sb->s_root->d_op; 747 return result; 748 } 749 750 static int 751 fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable) 752 { 753 int len = *lenp; 754 struct inode *inode = de->d_inode; 755 u32 ipos_h, ipos_m, ipos_l; 756 757 if (len < 5) 758 return 255; /* no room */ 759 760 ipos_h = MSDOS_I(inode)->i_pos >> 8; 761 ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24; 762 ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28; 763 *lenp = 5; 764 fh[0] = inode->i_ino; 765 fh[1] = inode->i_generation; 766 fh[2] = ipos_h; 767 fh[3] = ipos_m | MSDOS_I(inode)->i_logstart; 768 spin_lock(&de->d_lock); 769 fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart; 770 spin_unlock(&de->d_lock); 771 return 3; 772 } 773 774 static struct dentry *fat_get_parent(struct dentry *child) 775 { 776 struct super_block *sb = child->d_sb; 777 struct buffer_head *bh; 778 struct msdos_dir_entry *de; 779 loff_t i_pos; 780 struct dentry *parent; 781 struct inode *inode; 782 int err; 783 784 lock_super(sb); 785 786 err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos); 787 if (err) { 788 parent = ERR_PTR(err); 789 goto out; 790 } 791 inode = fat_build_inode(sb, de, i_pos); 792 brelse(bh); 793 794 parent = d_obtain_alias(inode); 795 if (!IS_ERR(parent)) 796 parent->d_op = sb->s_root->d_op; 797 out: 798 unlock_super(sb); 799 800 return parent; 801 } 802 803 static const struct export_operations fat_export_ops = { 804 .encode_fh = fat_encode_fh, 805 .fh_to_dentry = fat_fh_to_dentry, 806 .get_parent = fat_get_parent, 807 }; 808 809 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt) 810 { 811 struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb); 812 struct fat_mount_options *opts = &sbi->options; 813 int isvfat = opts->isvfat; 814 815 if (opts->fs_uid != 0) 816 seq_printf(m, ",uid=%u", opts->fs_uid); 817 if (opts->fs_gid != 0) 818 seq_printf(m, ",gid=%u", opts->fs_gid); 819 seq_printf(m, ",fmask=%04o", opts->fs_fmask); 820 seq_printf(m, ",dmask=%04o", opts->fs_dmask); 821 if (opts->allow_utime) 822 seq_printf(m, ",allow_utime=%04o", opts->allow_utime); 823 if (sbi->nls_disk) 824 seq_printf(m, ",codepage=%s", sbi->nls_disk->charset); 825 if (isvfat) { 826 if (sbi->nls_io) 827 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset); 828 829 switch (opts->shortname) { 830 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95: 831 seq_puts(m, ",shortname=win95"); 832 break; 833 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT: 834 seq_puts(m, ",shortname=winnt"); 835 break; 836 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95: 837 seq_puts(m, ",shortname=mixed"); 838 break; 839 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95: 840 seq_puts(m, ",shortname=lower"); 841 break; 842 default: 843 seq_puts(m, ",shortname=unknown"); 844 break; 845 } 846 } 847 if (opts->name_check != 'n') 848 seq_printf(m, ",check=%c", opts->name_check); 849 if (opts->usefree) 850 seq_puts(m, ",usefree"); 851 if (opts->quiet) 852 seq_puts(m, ",quiet"); 853 if (opts->showexec) 854 seq_puts(m, ",showexec"); 855 if (opts->sys_immutable) 856 seq_puts(m, ",sys_immutable"); 857 if (!isvfat) { 858 if (opts->dotsOK) 859 seq_puts(m, ",dotsOK=yes"); 860 if (opts->nocase) 861 seq_puts(m, ",nocase"); 862 } else { 863 if (opts->utf8) 864 seq_puts(m, ",utf8"); 865 if (opts->unicode_xlate) 866 seq_puts(m, ",uni_xlate"); 867 if (!opts->numtail) 868 seq_puts(m, ",nonumtail"); 869 if (opts->rodir) 870 seq_puts(m, ",rodir"); 871 } 872 if (opts->flush) 873 seq_puts(m, ",flush"); 874 if (opts->tz_utc) 875 seq_puts(m, ",tz=UTC"); 876 if (opts->errors == FAT_ERRORS_CONT) 877 seq_puts(m, ",errors=continue"); 878 else if (opts->errors == FAT_ERRORS_PANIC) 879 seq_puts(m, ",errors=panic"); 880 else 881 seq_puts(m, ",errors=remount-ro"); 882 if (opts->discard) 883 seq_puts(m, ",discard"); 884 885 return 0; 886 } 887 888 enum { 889 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid, 890 Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage, 891 Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug, 892 Opt_immutable, Opt_dots, Opt_nodots, 893 Opt_charset, Opt_shortname_lower, Opt_shortname_win95, 894 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes, 895 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes, 896 Opt_obsolate, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont, 897 Opt_err_panic, Opt_err_ro, Opt_discard, Opt_err, 898 }; 899 900 static const match_table_t fat_tokens = { 901 {Opt_check_r, "check=relaxed"}, 902 {Opt_check_s, "check=strict"}, 903 {Opt_check_n, "check=normal"}, 904 {Opt_check_r, "check=r"}, 905 {Opt_check_s, "check=s"}, 906 {Opt_check_n, "check=n"}, 907 {Opt_uid, "uid=%u"}, 908 {Opt_gid, "gid=%u"}, 909 {Opt_umask, "umask=%o"}, 910 {Opt_dmask, "dmask=%o"}, 911 {Opt_fmask, "fmask=%o"}, 912 {Opt_allow_utime, "allow_utime=%o"}, 913 {Opt_codepage, "codepage=%u"}, 914 {Opt_usefree, "usefree"}, 915 {Opt_nocase, "nocase"}, 916 {Opt_quiet, "quiet"}, 917 {Opt_showexec, "showexec"}, 918 {Opt_debug, "debug"}, 919 {Opt_immutable, "sys_immutable"}, 920 {Opt_flush, "flush"}, 921 {Opt_tz_utc, "tz=UTC"}, 922 {Opt_err_cont, "errors=continue"}, 923 {Opt_err_panic, "errors=panic"}, 924 {Opt_err_ro, "errors=remount-ro"}, 925 {Opt_discard, "discard"}, 926 {Opt_obsolate, "conv=binary"}, 927 {Opt_obsolate, "conv=text"}, 928 {Opt_obsolate, "conv=auto"}, 929 {Opt_obsolate, "conv=b"}, 930 {Opt_obsolate, "conv=t"}, 931 {Opt_obsolate, "conv=a"}, 932 {Opt_obsolate, "fat=%u"}, 933 {Opt_obsolate, "blocksize=%u"}, 934 {Opt_obsolate, "cvf_format=%20s"}, 935 {Opt_obsolate, "cvf_options=%100s"}, 936 {Opt_obsolate, "posix"}, 937 {Opt_err, NULL}, 938 }; 939 static const match_table_t msdos_tokens = { 940 {Opt_nodots, "nodots"}, 941 {Opt_nodots, "dotsOK=no"}, 942 {Opt_dots, "dots"}, 943 {Opt_dots, "dotsOK=yes"}, 944 {Opt_err, NULL} 945 }; 946 static const match_table_t vfat_tokens = { 947 {Opt_charset, "iocharset=%s"}, 948 {Opt_shortname_lower, "shortname=lower"}, 949 {Opt_shortname_win95, "shortname=win95"}, 950 {Opt_shortname_winnt, "shortname=winnt"}, 951 {Opt_shortname_mixed, "shortname=mixed"}, 952 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */ 953 {Opt_utf8_no, "utf8=no"}, 954 {Opt_utf8_no, "utf8=false"}, 955 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */ 956 {Opt_utf8_yes, "utf8=yes"}, 957 {Opt_utf8_yes, "utf8=true"}, 958 {Opt_utf8_yes, "utf8"}, 959 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */ 960 {Opt_uni_xl_no, "uni_xlate=no"}, 961 {Opt_uni_xl_no, "uni_xlate=false"}, 962 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */ 963 {Opt_uni_xl_yes, "uni_xlate=yes"}, 964 {Opt_uni_xl_yes, "uni_xlate=true"}, 965 {Opt_uni_xl_yes, "uni_xlate"}, 966 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */ 967 {Opt_nonumtail_no, "nonumtail=no"}, 968 {Opt_nonumtail_no, "nonumtail=false"}, 969 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */ 970 {Opt_nonumtail_yes, "nonumtail=yes"}, 971 {Opt_nonumtail_yes, "nonumtail=true"}, 972 {Opt_nonumtail_yes, "nonumtail"}, 973 {Opt_rodir, "rodir"}, 974 {Opt_err, NULL} 975 }; 976 977 static int parse_options(char *options, int is_vfat, int silent, int *debug, 978 struct fat_mount_options *opts) 979 { 980 char *p; 981 substring_t args[MAX_OPT_ARGS]; 982 int option; 983 char *iocharset; 984 985 opts->isvfat = is_vfat; 986 987 opts->fs_uid = current_uid(); 988 opts->fs_gid = current_gid(); 989 opts->fs_fmask = opts->fs_dmask = current_umask(); 990 opts->allow_utime = -1; 991 opts->codepage = fat_default_codepage; 992 opts->iocharset = fat_default_iocharset; 993 if (is_vfat) { 994 opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95; 995 opts->rodir = 0; 996 } else { 997 opts->shortname = 0; 998 opts->rodir = 1; 999 } 1000 opts->name_check = 'n'; 1001 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0; 1002 opts->utf8 = opts->unicode_xlate = 0; 1003 opts->numtail = 1; 1004 opts->usefree = opts->nocase = 0; 1005 opts->tz_utc = 0; 1006 opts->errors = FAT_ERRORS_RO; 1007 *debug = 0; 1008 1009 if (!options) 1010 goto out; 1011 1012 while ((p = strsep(&options, ",")) != NULL) { 1013 int token; 1014 if (!*p) 1015 continue; 1016 1017 token = match_token(p, fat_tokens, args); 1018 if (token == Opt_err) { 1019 if (is_vfat) 1020 token = match_token(p, vfat_tokens, args); 1021 else 1022 token = match_token(p, msdos_tokens, args); 1023 } 1024 switch (token) { 1025 case Opt_check_s: 1026 opts->name_check = 's'; 1027 break; 1028 case Opt_check_r: 1029 opts->name_check = 'r'; 1030 break; 1031 case Opt_check_n: 1032 opts->name_check = 'n'; 1033 break; 1034 case Opt_usefree: 1035 opts->usefree = 1; 1036 break; 1037 case Opt_nocase: 1038 if (!is_vfat) 1039 opts->nocase = 1; 1040 else { 1041 /* for backward compatibility */ 1042 opts->shortname = VFAT_SFN_DISPLAY_WIN95 1043 | VFAT_SFN_CREATE_WIN95; 1044 } 1045 break; 1046 case Opt_quiet: 1047 opts->quiet = 1; 1048 break; 1049 case Opt_showexec: 1050 opts->showexec = 1; 1051 break; 1052 case Opt_debug: 1053 *debug = 1; 1054 break; 1055 case Opt_immutable: 1056 opts->sys_immutable = 1; 1057 break; 1058 case Opt_uid: 1059 if (match_int(&args[0], &option)) 1060 return 0; 1061 opts->fs_uid = option; 1062 break; 1063 case Opt_gid: 1064 if (match_int(&args[0], &option)) 1065 return 0; 1066 opts->fs_gid = option; 1067 break; 1068 case Opt_umask: 1069 if (match_octal(&args[0], &option)) 1070 return 0; 1071 opts->fs_fmask = opts->fs_dmask = option; 1072 break; 1073 case Opt_dmask: 1074 if (match_octal(&args[0], &option)) 1075 return 0; 1076 opts->fs_dmask = option; 1077 break; 1078 case Opt_fmask: 1079 if (match_octal(&args[0], &option)) 1080 return 0; 1081 opts->fs_fmask = option; 1082 break; 1083 case Opt_allow_utime: 1084 if (match_octal(&args[0], &option)) 1085 return 0; 1086 opts->allow_utime = option & (S_IWGRP | S_IWOTH); 1087 break; 1088 case Opt_codepage: 1089 if (match_int(&args[0], &option)) 1090 return 0; 1091 opts->codepage = option; 1092 break; 1093 case Opt_flush: 1094 opts->flush = 1; 1095 break; 1096 case Opt_tz_utc: 1097 opts->tz_utc = 1; 1098 break; 1099 case Opt_err_cont: 1100 opts->errors = FAT_ERRORS_CONT; 1101 break; 1102 case Opt_err_panic: 1103 opts->errors = FAT_ERRORS_PANIC; 1104 break; 1105 case Opt_err_ro: 1106 opts->errors = FAT_ERRORS_RO; 1107 break; 1108 1109 /* msdos specific */ 1110 case Opt_dots: 1111 opts->dotsOK = 1; 1112 break; 1113 case Opt_nodots: 1114 opts->dotsOK = 0; 1115 break; 1116 1117 /* vfat specific */ 1118 case Opt_charset: 1119 if (opts->iocharset != fat_default_iocharset) 1120 kfree(opts->iocharset); 1121 iocharset = match_strdup(&args[0]); 1122 if (!iocharset) 1123 return -ENOMEM; 1124 opts->iocharset = iocharset; 1125 break; 1126 case Opt_shortname_lower: 1127 opts->shortname = VFAT_SFN_DISPLAY_LOWER 1128 | VFAT_SFN_CREATE_WIN95; 1129 break; 1130 case Opt_shortname_win95: 1131 opts->shortname = VFAT_SFN_DISPLAY_WIN95 1132 | VFAT_SFN_CREATE_WIN95; 1133 break; 1134 case Opt_shortname_winnt: 1135 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1136 | VFAT_SFN_CREATE_WINNT; 1137 break; 1138 case Opt_shortname_mixed: 1139 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1140 | VFAT_SFN_CREATE_WIN95; 1141 break; 1142 case Opt_utf8_no: /* 0 or no or false */ 1143 opts->utf8 = 0; 1144 break; 1145 case Opt_utf8_yes: /* empty or 1 or yes or true */ 1146 opts->utf8 = 1; 1147 break; 1148 case Opt_uni_xl_no: /* 0 or no or false */ 1149 opts->unicode_xlate = 0; 1150 break; 1151 case Opt_uni_xl_yes: /* empty or 1 or yes or true */ 1152 opts->unicode_xlate = 1; 1153 break; 1154 case Opt_nonumtail_no: /* 0 or no or false */ 1155 opts->numtail = 1; /* negated option */ 1156 break; 1157 case Opt_nonumtail_yes: /* empty or 1 or yes or true */ 1158 opts->numtail = 0; /* negated option */ 1159 break; 1160 case Opt_rodir: 1161 opts->rodir = 1; 1162 break; 1163 case Opt_discard: 1164 opts->discard = 1; 1165 break; 1166 1167 /* obsolete mount options */ 1168 case Opt_obsolate: 1169 printk(KERN_INFO "FAT: \"%s\" option is obsolete, " 1170 "not supported now\n", p); 1171 break; 1172 /* unknown option */ 1173 default: 1174 if (!silent) { 1175 printk(KERN_ERR 1176 "FAT: Unrecognized mount option \"%s\" " 1177 "or missing value\n", p); 1178 } 1179 return -EINVAL; 1180 } 1181 } 1182 1183 out: 1184 /* UTF-8 doesn't provide FAT semantics */ 1185 if (!strcmp(opts->iocharset, "utf8")) { 1186 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset" 1187 " for FAT filesystems, filesystem will be " 1188 "case sensitive!\n"); 1189 } 1190 1191 /* If user doesn't specify allow_utime, it's initialized from dmask. */ 1192 if (opts->allow_utime == (unsigned short)-1) 1193 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH); 1194 if (opts->unicode_xlate) 1195 opts->utf8 = 0; 1196 1197 return 0; 1198 } 1199 1200 static int fat_read_root(struct inode *inode) 1201 { 1202 struct super_block *sb = inode->i_sb; 1203 struct msdos_sb_info *sbi = MSDOS_SB(sb); 1204 int error; 1205 1206 MSDOS_I(inode)->i_pos = 0; 1207 inode->i_uid = sbi->options.fs_uid; 1208 inode->i_gid = sbi->options.fs_gid; 1209 inode->i_version++; 1210 inode->i_generation = 0; 1211 inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO); 1212 inode->i_op = sbi->dir_ops; 1213 inode->i_fop = &fat_dir_operations; 1214 if (sbi->fat_bits == 32) { 1215 MSDOS_I(inode)->i_start = sbi->root_cluster; 1216 error = fat_calc_dir_size(inode); 1217 if (error < 0) 1218 return error; 1219 } else { 1220 MSDOS_I(inode)->i_start = 0; 1221 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry); 1222 } 1223 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 1224 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 1225 MSDOS_I(inode)->i_logstart = 0; 1226 MSDOS_I(inode)->mmu_private = inode->i_size; 1227 1228 fat_save_attrs(inode, ATTR_DIR); 1229 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0; 1230 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0; 1231 inode->i_nlink = fat_subdirs(inode)+2; 1232 1233 return 0; 1234 } 1235 1236 /* 1237 * Read the super block of an MS-DOS FS. 1238 */ 1239 int fat_fill_super(struct super_block *sb, void *data, int silent, 1240 const struct inode_operations *fs_dir_inode_ops, int isvfat) 1241 { 1242 struct inode *root_inode = NULL, *fat_inode = NULL; 1243 struct buffer_head *bh; 1244 struct fat_boot_sector *b; 1245 struct msdos_sb_info *sbi; 1246 u16 logical_sector_size; 1247 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors; 1248 int debug; 1249 unsigned int media; 1250 long error; 1251 char buf[50]; 1252 1253 /* 1254 * GFP_KERNEL is ok here, because while we do hold the 1255 * supeblock lock, memory pressure can't call back into 1256 * the filesystem, since we're only just about to mount 1257 * it and have no inodes etc active! 1258 */ 1259 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL); 1260 if (!sbi) 1261 return -ENOMEM; 1262 sb->s_fs_info = sbi; 1263 1264 sb->s_flags |= MS_NODIRATIME; 1265 sb->s_magic = MSDOS_SUPER_MAGIC; 1266 sb->s_op = &fat_sops; 1267 sb->s_export_op = &fat_export_ops; 1268 sbi->dir_ops = fs_dir_inode_ops; 1269 ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL, 1270 DEFAULT_RATELIMIT_BURST); 1271 1272 error = parse_options(data, isvfat, silent, &debug, &sbi->options); 1273 if (error) 1274 goto out_fail; 1275 1276 error = -EIO; 1277 sb_min_blocksize(sb, 512); 1278 bh = sb_bread(sb, 0); 1279 if (bh == NULL) { 1280 printk(KERN_ERR "FAT: unable to read boot sector\n"); 1281 goto out_fail; 1282 } 1283 1284 b = (struct fat_boot_sector *) bh->b_data; 1285 if (!b->reserved) { 1286 if (!silent) 1287 printk(KERN_ERR "FAT: bogus number of reserved sectors\n"); 1288 brelse(bh); 1289 goto out_invalid; 1290 } 1291 if (!b->fats) { 1292 if (!silent) 1293 printk(KERN_ERR "FAT: bogus number of FAT structure\n"); 1294 brelse(bh); 1295 goto out_invalid; 1296 } 1297 1298 /* 1299 * Earlier we checked here that b->secs_track and b->head are nonzero, 1300 * but it turns out valid FAT filesystems can have zero there. 1301 */ 1302 1303 media = b->media; 1304 if (!fat_valid_media(media)) { 1305 if (!silent) 1306 printk(KERN_ERR "FAT: invalid media value (0x%02x)\n", 1307 media); 1308 brelse(bh); 1309 goto out_invalid; 1310 } 1311 logical_sector_size = get_unaligned_le16(&b->sector_size); 1312 if (!is_power_of_2(logical_sector_size) 1313 || (logical_sector_size < 512) 1314 || (logical_sector_size > 4096)) { 1315 if (!silent) 1316 printk(KERN_ERR "FAT: bogus logical sector size %u\n", 1317 logical_sector_size); 1318 brelse(bh); 1319 goto out_invalid; 1320 } 1321 sbi->sec_per_clus = b->sec_per_clus; 1322 if (!is_power_of_2(sbi->sec_per_clus)) { 1323 if (!silent) 1324 printk(KERN_ERR "FAT: bogus sectors per cluster %u\n", 1325 sbi->sec_per_clus); 1326 brelse(bh); 1327 goto out_invalid; 1328 } 1329 1330 if (logical_sector_size < sb->s_blocksize) { 1331 printk(KERN_ERR "FAT: logical sector size too small for device" 1332 " (logical sector size = %u)\n", logical_sector_size); 1333 brelse(bh); 1334 goto out_fail; 1335 } 1336 if (logical_sector_size > sb->s_blocksize) { 1337 brelse(bh); 1338 1339 if (!sb_set_blocksize(sb, logical_sector_size)) { 1340 printk(KERN_ERR "FAT: unable to set blocksize %u\n", 1341 logical_sector_size); 1342 goto out_fail; 1343 } 1344 bh = sb_bread(sb, 0); 1345 if (bh == NULL) { 1346 printk(KERN_ERR "FAT: unable to read boot sector" 1347 " (logical sector size = %lu)\n", 1348 sb->s_blocksize); 1349 goto out_fail; 1350 } 1351 b = (struct fat_boot_sector *) bh->b_data; 1352 } 1353 1354 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus; 1355 sbi->cluster_bits = ffs(sbi->cluster_size) - 1; 1356 sbi->fats = b->fats; 1357 sbi->fat_bits = 0; /* Don't know yet */ 1358 sbi->fat_start = le16_to_cpu(b->reserved); 1359 sbi->fat_length = le16_to_cpu(b->fat_length); 1360 sbi->root_cluster = 0; 1361 sbi->free_clusters = -1; /* Don't know yet */ 1362 sbi->free_clus_valid = 0; 1363 sbi->prev_free = FAT_START_ENT; 1364 1365 if (!sbi->fat_length && b->fat32_length) { 1366 struct fat_boot_fsinfo *fsinfo; 1367 struct buffer_head *fsinfo_bh; 1368 1369 /* Must be FAT32 */ 1370 sbi->fat_bits = 32; 1371 sbi->fat_length = le32_to_cpu(b->fat32_length); 1372 sbi->root_cluster = le32_to_cpu(b->root_cluster); 1373 1374 sb->s_maxbytes = 0xffffffff; 1375 1376 /* MC - if info_sector is 0, don't multiply by 0 */ 1377 sbi->fsinfo_sector = le16_to_cpu(b->info_sector); 1378 if (sbi->fsinfo_sector == 0) 1379 sbi->fsinfo_sector = 1; 1380 1381 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector); 1382 if (fsinfo_bh == NULL) { 1383 printk(KERN_ERR "FAT: bread failed, FSINFO block" 1384 " (sector = %lu)\n", sbi->fsinfo_sector); 1385 brelse(bh); 1386 goto out_fail; 1387 } 1388 1389 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data; 1390 if (!IS_FSINFO(fsinfo)) { 1391 printk(KERN_WARNING "FAT: Invalid FSINFO signature: " 1392 "0x%08x, 0x%08x (sector = %lu)\n", 1393 le32_to_cpu(fsinfo->signature1), 1394 le32_to_cpu(fsinfo->signature2), 1395 sbi->fsinfo_sector); 1396 } else { 1397 if (sbi->options.usefree) 1398 sbi->free_clus_valid = 1; 1399 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters); 1400 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster); 1401 } 1402 1403 brelse(fsinfo_bh); 1404 } 1405 1406 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry); 1407 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1; 1408 1409 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length; 1410 sbi->dir_entries = get_unaligned_le16(&b->dir_entries); 1411 if (sbi->dir_entries & (sbi->dir_per_block - 1)) { 1412 if (!silent) 1413 printk(KERN_ERR "FAT: bogus directroy-entries per block" 1414 " (%u)\n", sbi->dir_entries); 1415 brelse(bh); 1416 goto out_invalid; 1417 } 1418 1419 rootdir_sectors = sbi->dir_entries 1420 * sizeof(struct msdos_dir_entry) / sb->s_blocksize; 1421 sbi->data_start = sbi->dir_start + rootdir_sectors; 1422 total_sectors = get_unaligned_le16(&b->sectors); 1423 if (total_sectors == 0) 1424 total_sectors = le32_to_cpu(b->total_sect); 1425 1426 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus; 1427 1428 if (sbi->fat_bits != 32) 1429 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12; 1430 1431 /* check that FAT table does not overflow */ 1432 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits; 1433 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT); 1434 if (total_clusters > MAX_FAT(sb)) { 1435 if (!silent) 1436 printk(KERN_ERR "FAT: count of clusters too big (%u)\n", 1437 total_clusters); 1438 brelse(bh); 1439 goto out_invalid; 1440 } 1441 1442 sbi->max_cluster = total_clusters + FAT_START_ENT; 1443 /* check the free_clusters, it's not necessarily correct */ 1444 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters) 1445 sbi->free_clusters = -1; 1446 /* check the prev_free, it's not necessarily correct */ 1447 sbi->prev_free %= sbi->max_cluster; 1448 if (sbi->prev_free < FAT_START_ENT) 1449 sbi->prev_free = FAT_START_ENT; 1450 1451 brelse(bh); 1452 1453 /* set up enough so that it can read an inode */ 1454 fat_hash_init(sb); 1455 fat_ent_access_init(sb); 1456 1457 /* 1458 * The low byte of FAT's first entry must have same value with 1459 * media-field. But in real world, too many devices is 1460 * writing wrong value. So, removed that validity check. 1461 * 1462 * if (FAT_FIRST_ENT(sb, media) != first) 1463 */ 1464 1465 error = -EINVAL; 1466 sprintf(buf, "cp%d", sbi->options.codepage); 1467 sbi->nls_disk = load_nls(buf); 1468 if (!sbi->nls_disk) { 1469 printk(KERN_ERR "FAT: codepage %s not found\n", buf); 1470 goto out_fail; 1471 } 1472 1473 /* FIXME: utf8 is using iocharset for upper/lower conversion */ 1474 if (sbi->options.isvfat) { 1475 sbi->nls_io = load_nls(sbi->options.iocharset); 1476 if (!sbi->nls_io) { 1477 printk(KERN_ERR "FAT: IO charset %s not found\n", 1478 sbi->options.iocharset); 1479 goto out_fail; 1480 } 1481 } 1482 1483 error = -ENOMEM; 1484 fat_inode = new_inode(sb); 1485 if (!fat_inode) 1486 goto out_fail; 1487 MSDOS_I(fat_inode)->i_pos = 0; 1488 sbi->fat_inode = fat_inode; 1489 root_inode = new_inode(sb); 1490 if (!root_inode) 1491 goto out_fail; 1492 root_inode->i_ino = MSDOS_ROOT_INO; 1493 root_inode->i_version = 1; 1494 error = fat_read_root(root_inode); 1495 if (error < 0) 1496 goto out_fail; 1497 error = -ENOMEM; 1498 insert_inode_hash(root_inode); 1499 sb->s_root = d_alloc_root(root_inode); 1500 if (!sb->s_root) { 1501 printk(KERN_ERR "FAT: get root inode failed\n"); 1502 goto out_fail; 1503 } 1504 1505 return 0; 1506 1507 out_invalid: 1508 error = -EINVAL; 1509 if (!silent) 1510 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem" 1511 " on dev %s.\n", sb->s_id); 1512 1513 out_fail: 1514 if (fat_inode) 1515 iput(fat_inode); 1516 if (root_inode) 1517 iput(root_inode); 1518 unload_nls(sbi->nls_io); 1519 unload_nls(sbi->nls_disk); 1520 if (sbi->options.iocharset != fat_default_iocharset) 1521 kfree(sbi->options.iocharset); 1522 sb->s_fs_info = NULL; 1523 kfree(sbi); 1524 return error; 1525 } 1526 1527 EXPORT_SYMBOL_GPL(fat_fill_super); 1528 1529 /* 1530 * helper function for fat_flush_inodes. This writes both the inode 1531 * and the file data blocks, waiting for in flight data blocks before 1532 * the start of the call. It does not wait for any io started 1533 * during the call 1534 */ 1535 static int writeback_inode(struct inode *inode) 1536 { 1537 1538 int ret; 1539 struct address_space *mapping = inode->i_mapping; 1540 struct writeback_control wbc = { 1541 .sync_mode = WB_SYNC_NONE, 1542 .nr_to_write = 0, 1543 }; 1544 /* if we used WB_SYNC_ALL, sync_inode waits for the io for the 1545 * inode to finish. So WB_SYNC_NONE is sent down to sync_inode 1546 * and filemap_fdatawrite is used for the data blocks 1547 */ 1548 ret = sync_inode(inode, &wbc); 1549 if (!ret) 1550 ret = filemap_fdatawrite(mapping); 1551 return ret; 1552 } 1553 1554 /* 1555 * write data and metadata corresponding to i1 and i2. The io is 1556 * started but we do not wait for any of it to finish. 1557 * 1558 * filemap_flush is used for the block device, so if there is a dirty 1559 * page for a block already in flight, we will not wait and start the 1560 * io over again 1561 */ 1562 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2) 1563 { 1564 int ret = 0; 1565 if (!MSDOS_SB(sb)->options.flush) 1566 return 0; 1567 if (i1) 1568 ret = writeback_inode(i1); 1569 if (!ret && i2) 1570 ret = writeback_inode(i2); 1571 if (!ret) { 1572 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping; 1573 ret = filemap_flush(mapping); 1574 } 1575 return ret; 1576 } 1577 EXPORT_SYMBOL_GPL(fat_flush_inodes); 1578 1579 static int __init init_fat_fs(void) 1580 { 1581 int err; 1582 1583 err = fat_cache_init(); 1584 if (err) 1585 return err; 1586 1587 err = fat_init_inodecache(); 1588 if (err) 1589 goto failed; 1590 1591 return 0; 1592 1593 failed: 1594 fat_cache_destroy(); 1595 return err; 1596 } 1597 1598 static void __exit exit_fat_fs(void) 1599 { 1600 fat_cache_destroy(); 1601 fat_destroy_inodecache(); 1602 } 1603 1604 module_init(init_fat_fs) 1605 module_exit(exit_fat_fs) 1606 1607 MODULE_LICENSE("GPL"); 1608