1 /* 2 * linux/fs/fat/inode.c 3 * 4 * Written 1992,1993 by Werner Almesberger 5 * VFAT extensions by Gordon Chaffee, merged with msdos fs by Henrik Storner 6 * Rewritten for the constant inumbers support by Al Viro 7 * 8 * Fixes: 9 * 10 * Max Cohan: Fixed invalid FSINFO offset when info_sector is 0 11 */ 12 13 #include <linux/module.h> 14 #include <linux/init.h> 15 #include <linux/time.h> 16 #include <linux/slab.h> 17 #include <linux/smp_lock.h> 18 #include <linux/seq_file.h> 19 #include <linux/msdos_fs.h> 20 #include <linux/pagemap.h> 21 #include <linux/mpage.h> 22 #include <linux/buffer_head.h> 23 #include <linux/exportfs.h> 24 #include <linux/mount.h> 25 #include <linux/vfs.h> 26 #include <linux/parser.h> 27 #include <linux/uio.h> 28 #include <linux/writeback.h> 29 #include <linux/log2.h> 30 #include <asm/unaligned.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); 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_panic(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); 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 int fat_write_begin(struct file *file, struct address_space *mapping, 145 loff_t pos, unsigned len, unsigned flags, 146 struct page **pagep, void **fsdata) 147 { 148 *pagep = NULL; 149 return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata, 150 fat_get_block, 151 &MSDOS_I(mapping->host)->mmu_private); 152 } 153 154 static int fat_write_end(struct file *file, struct address_space *mapping, 155 loff_t pos, unsigned len, unsigned copied, 156 struct page *pagep, void *fsdata) 157 { 158 struct inode *inode = mapping->host; 159 int err; 160 err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata); 161 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) { 162 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC; 163 MSDOS_I(inode)->i_attrs |= ATTR_ARCH; 164 mark_inode_dirty(inode); 165 } 166 return err; 167 } 168 169 static ssize_t fat_direct_IO(int rw, struct kiocb *iocb, 170 const struct iovec *iov, 171 loff_t offset, unsigned long nr_segs) 172 { 173 struct file *file = iocb->ki_filp; 174 struct inode *inode = file->f_mapping->host; 175 176 if (rw == WRITE) { 177 /* 178 * FIXME: blockdev_direct_IO() doesn't use ->prepare_write(), 179 * so we need to update the ->mmu_private to block boundary. 180 * 181 * But we must fill the remaining area or hole by nul for 182 * updating ->mmu_private. 183 * 184 * Return 0, and fallback to normal buffered write. 185 */ 186 loff_t size = offset + iov_length(iov, nr_segs); 187 if (MSDOS_I(inode)->mmu_private < size) 188 return 0; 189 } 190 191 /* 192 * FAT need to use the DIO_LOCKING for avoiding the race 193 * condition of fat_get_block() and ->truncate(). 194 */ 195 return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov, 196 offset, nr_segs, fat_get_block, NULL); 197 } 198 199 static sector_t _fat_bmap(struct address_space *mapping, sector_t block) 200 { 201 return generic_block_bmap(mapping, block, fat_get_block); 202 } 203 204 static const struct address_space_operations fat_aops = { 205 .readpage = fat_readpage, 206 .readpages = fat_readpages, 207 .writepage = fat_writepage, 208 .writepages = fat_writepages, 209 .sync_page = block_sync_page, 210 .write_begin = fat_write_begin, 211 .write_end = fat_write_end, 212 .direct_IO = fat_direct_IO, 213 .bmap = _fat_bmap 214 }; 215 216 /* 217 * New FAT inode stuff. We do the following: 218 * a) i_ino is constant and has nothing with on-disk location. 219 * b) FAT manages its own cache of directory entries. 220 * c) *This* cache is indexed by on-disk location. 221 * d) inode has an associated directory entry, all right, but 222 * it may be unhashed. 223 * e) currently entries are stored within struct inode. That should 224 * change. 225 * f) we deal with races in the following way: 226 * 1. readdir() and lookup() do FAT-dir-cache lookup. 227 * 2. rename() unhashes the F-d-c entry and rehashes it in 228 * a new place. 229 * 3. unlink() and rmdir() unhash F-d-c entry. 230 * 4. fat_write_inode() checks whether the thing is unhashed. 231 * If it is we silently return. If it isn't we do bread(), 232 * check if the location is still valid and retry if it 233 * isn't. Otherwise we do changes. 234 * 5. Spinlock is used to protect hash/unhash/location check/lookup 235 * 6. fat_clear_inode() unhashes the F-d-c entry. 236 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry 237 * and consider negative result as cache miss. 238 */ 239 240 static void fat_hash_init(struct super_block *sb) 241 { 242 struct msdos_sb_info *sbi = MSDOS_SB(sb); 243 int i; 244 245 spin_lock_init(&sbi->inode_hash_lock); 246 for (i = 0; i < FAT_HASH_SIZE; i++) 247 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]); 248 } 249 250 static inline unsigned long fat_hash(struct super_block *sb, loff_t i_pos) 251 { 252 unsigned long tmp = (unsigned long)i_pos | (unsigned long) sb; 253 tmp = tmp + (tmp >> FAT_HASH_BITS) + (tmp >> FAT_HASH_BITS * 2); 254 return tmp & FAT_HASH_MASK; 255 } 256 257 void fat_attach(struct inode *inode, loff_t i_pos) 258 { 259 struct super_block *sb = inode->i_sb; 260 struct msdos_sb_info *sbi = MSDOS_SB(sb); 261 262 spin_lock(&sbi->inode_hash_lock); 263 MSDOS_I(inode)->i_pos = i_pos; 264 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, 265 sbi->inode_hashtable + fat_hash(sb, i_pos)); 266 spin_unlock(&sbi->inode_hash_lock); 267 } 268 269 EXPORT_SYMBOL_GPL(fat_attach); 270 271 void fat_detach(struct inode *inode) 272 { 273 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 274 spin_lock(&sbi->inode_hash_lock); 275 MSDOS_I(inode)->i_pos = 0; 276 hlist_del_init(&MSDOS_I(inode)->i_fat_hash); 277 spin_unlock(&sbi->inode_hash_lock); 278 } 279 280 EXPORT_SYMBOL_GPL(fat_detach); 281 282 struct inode *fat_iget(struct super_block *sb, loff_t i_pos) 283 { 284 struct msdos_sb_info *sbi = MSDOS_SB(sb); 285 struct hlist_head *head = sbi->inode_hashtable + fat_hash(sb, i_pos); 286 struct hlist_node *_p; 287 struct msdos_inode_info *i; 288 struct inode *inode = NULL; 289 290 spin_lock(&sbi->inode_hash_lock); 291 hlist_for_each_entry(i, _p, head, i_fat_hash) { 292 BUG_ON(i->vfs_inode.i_sb != sb); 293 if (i->i_pos != i_pos) 294 continue; 295 inode = igrab(&i->vfs_inode); 296 if (inode) 297 break; 298 } 299 spin_unlock(&sbi->inode_hash_lock); 300 return inode; 301 } 302 303 static int is_exec(unsigned char *extension) 304 { 305 unsigned char *exe_extensions = "EXECOMBAT", *walk; 306 307 for (walk = exe_extensions; *walk; walk += 3) 308 if (!strncmp(extension, walk, 3)) 309 return 1; 310 return 0; 311 } 312 313 static int fat_calc_dir_size(struct inode *inode) 314 { 315 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 316 int ret, fclus, dclus; 317 318 inode->i_size = 0; 319 if (MSDOS_I(inode)->i_start == 0) 320 return 0; 321 322 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); 323 if (ret < 0) 324 return ret; 325 inode->i_size = (fclus + 1) << sbi->cluster_bits; 326 327 return 0; 328 } 329 330 /* doesn't deal with root inode */ 331 static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de) 332 { 333 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 334 int error; 335 336 MSDOS_I(inode)->i_pos = 0; 337 inode->i_uid = sbi->options.fs_uid; 338 inode->i_gid = sbi->options.fs_gid; 339 inode->i_version++; 340 inode->i_generation = get_seconds(); 341 342 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) { 343 inode->i_generation &= ~1; 344 inode->i_mode = MSDOS_MKMODE(de->attr, 345 S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR; 346 inode->i_op = sbi->dir_ops; 347 inode->i_fop = &fat_dir_operations; 348 349 MSDOS_I(inode)->i_start = le16_to_cpu(de->start); 350 if (sbi->fat_bits == 32) 351 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16); 352 353 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 354 error = fat_calc_dir_size(inode); 355 if (error < 0) 356 return error; 357 MSDOS_I(inode)->mmu_private = inode->i_size; 358 359 inode->i_nlink = fat_subdirs(inode); 360 } else { /* not a directory */ 361 inode->i_generation |= 1; 362 inode->i_mode = MSDOS_MKMODE(de->attr, 363 ((sbi->options.showexec && !is_exec(de->name + 8)) 364 ? S_IRUGO|S_IWUGO : S_IRWXUGO) 365 & ~sbi->options.fs_fmask) | S_IFREG; 366 MSDOS_I(inode)->i_start = le16_to_cpu(de->start); 367 if (sbi->fat_bits == 32) 368 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16); 369 370 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start; 371 inode->i_size = le32_to_cpu(de->size); 372 inode->i_op = &fat_file_inode_operations; 373 inode->i_fop = &fat_file_operations; 374 inode->i_mapping->a_ops = &fat_aops; 375 MSDOS_I(inode)->mmu_private = inode->i_size; 376 } 377 if (de->attr & ATTR_SYS) { 378 if (sbi->options.sys_immutable) 379 inode->i_flags |= S_IMMUTABLE; 380 } 381 MSDOS_I(inode)->i_attrs = de->attr & ATTR_UNUSED; 382 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 383 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 384 inode->i_mtime.tv_sec = 385 date_dos2unix(le16_to_cpu(de->time), le16_to_cpu(de->date), 386 sbi->options.tz_utc); 387 inode->i_mtime.tv_nsec = 0; 388 if (sbi->options.isvfat) { 389 int secs = de->ctime_cs / 100; 390 int csecs = de->ctime_cs % 100; 391 inode->i_ctime.tv_sec = 392 date_dos2unix(le16_to_cpu(de->ctime), 393 le16_to_cpu(de->cdate), 394 sbi->options.tz_utc) + secs; 395 inode->i_ctime.tv_nsec = csecs * 10000000; 396 inode->i_atime.tv_sec = 397 date_dos2unix(0, le16_to_cpu(de->adate), 398 sbi->options.tz_utc); 399 inode->i_atime.tv_nsec = 0; 400 } else 401 inode->i_ctime = inode->i_atime = inode->i_mtime; 402 403 return 0; 404 } 405 406 struct inode *fat_build_inode(struct super_block *sb, 407 struct msdos_dir_entry *de, loff_t i_pos) 408 { 409 struct inode *inode; 410 int err; 411 412 inode = fat_iget(sb, i_pos); 413 if (inode) 414 goto out; 415 inode = new_inode(sb); 416 if (!inode) { 417 inode = ERR_PTR(-ENOMEM); 418 goto out; 419 } 420 inode->i_ino = iunique(sb, MSDOS_ROOT_INO); 421 inode->i_version = 1; 422 err = fat_fill_inode(inode, de); 423 if (err) { 424 iput(inode); 425 inode = ERR_PTR(err); 426 goto out; 427 } 428 fat_attach(inode, i_pos); 429 insert_inode_hash(inode); 430 out: 431 return inode; 432 } 433 434 EXPORT_SYMBOL_GPL(fat_build_inode); 435 436 static void fat_delete_inode(struct inode *inode) 437 { 438 truncate_inode_pages(&inode->i_data, 0); 439 inode->i_size = 0; 440 fat_truncate(inode); 441 clear_inode(inode); 442 } 443 444 static void fat_clear_inode(struct inode *inode) 445 { 446 struct super_block *sb = inode->i_sb; 447 struct msdos_sb_info *sbi = MSDOS_SB(sb); 448 449 spin_lock(&sbi->inode_hash_lock); 450 fat_cache_inval_inode(inode); 451 hlist_del_init(&MSDOS_I(inode)->i_fat_hash); 452 spin_unlock(&sbi->inode_hash_lock); 453 } 454 455 static void fat_write_super(struct super_block *sb) 456 { 457 sb->s_dirt = 0; 458 459 if (!(sb->s_flags & MS_RDONLY)) 460 fat_clusters_flush(sb); 461 } 462 463 static void fat_put_super(struct super_block *sb) 464 { 465 struct msdos_sb_info *sbi = MSDOS_SB(sb); 466 467 if (sbi->nls_disk) { 468 unload_nls(sbi->nls_disk); 469 sbi->nls_disk = NULL; 470 sbi->options.codepage = fat_default_codepage; 471 } 472 if (sbi->nls_io) { 473 unload_nls(sbi->nls_io); 474 sbi->nls_io = NULL; 475 } 476 if (sbi->options.iocharset != fat_default_iocharset) { 477 kfree(sbi->options.iocharset); 478 sbi->options.iocharset = fat_default_iocharset; 479 } 480 481 sb->s_fs_info = NULL; 482 kfree(sbi); 483 } 484 485 static struct kmem_cache *fat_inode_cachep; 486 487 static struct inode *fat_alloc_inode(struct super_block *sb) 488 { 489 struct msdos_inode_info *ei; 490 ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS); 491 if (!ei) 492 return NULL; 493 return &ei->vfs_inode; 494 } 495 496 static void fat_destroy_inode(struct inode *inode) 497 { 498 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode)); 499 } 500 501 static void init_once(void *foo) 502 { 503 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo; 504 505 spin_lock_init(&ei->cache_lru_lock); 506 ei->nr_caches = 0; 507 ei->cache_valid_id = FAT_CACHE_VALID + 1; 508 INIT_LIST_HEAD(&ei->cache_lru); 509 INIT_HLIST_NODE(&ei->i_fat_hash); 510 inode_init_once(&ei->vfs_inode); 511 } 512 513 static int __init fat_init_inodecache(void) 514 { 515 fat_inode_cachep = kmem_cache_create("fat_inode_cache", 516 sizeof(struct msdos_inode_info), 517 0, (SLAB_RECLAIM_ACCOUNT| 518 SLAB_MEM_SPREAD), 519 init_once); 520 if (fat_inode_cachep == NULL) 521 return -ENOMEM; 522 return 0; 523 } 524 525 static void __exit fat_destroy_inodecache(void) 526 { 527 kmem_cache_destroy(fat_inode_cachep); 528 } 529 530 static int fat_remount(struct super_block *sb, int *flags, char *data) 531 { 532 struct msdos_sb_info *sbi = MSDOS_SB(sb); 533 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME); 534 return 0; 535 } 536 537 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf) 538 { 539 struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb); 540 541 /* If the count of free cluster is still unknown, counts it here. */ 542 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) { 543 int err = fat_count_free_clusters(dentry->d_sb); 544 if (err) 545 return err; 546 } 547 548 buf->f_type = dentry->d_sb->s_magic; 549 buf->f_bsize = sbi->cluster_size; 550 buf->f_blocks = sbi->max_cluster - FAT_START_ENT; 551 buf->f_bfree = sbi->free_clusters; 552 buf->f_bavail = sbi->free_clusters; 553 buf->f_namelen = sbi->options.isvfat ? 260 : 12; 554 555 return 0; 556 } 557 558 static int fat_write_inode(struct inode *inode, int wait) 559 { 560 struct super_block *sb = inode->i_sb; 561 struct msdos_sb_info *sbi = MSDOS_SB(sb); 562 struct buffer_head *bh; 563 struct msdos_dir_entry *raw_entry; 564 loff_t i_pos; 565 int err; 566 567 retry: 568 i_pos = MSDOS_I(inode)->i_pos; 569 if (inode->i_ino == MSDOS_ROOT_INO || !i_pos) 570 return 0; 571 572 bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits); 573 if (!bh) { 574 printk(KERN_ERR "FAT: unable to read inode block " 575 "for updating (i_pos %lld)\n", i_pos); 576 return -EIO; 577 } 578 spin_lock(&sbi->inode_hash_lock); 579 if (i_pos != MSDOS_I(inode)->i_pos) { 580 spin_unlock(&sbi->inode_hash_lock); 581 brelse(bh); 582 goto retry; 583 } 584 585 raw_entry = &((struct msdos_dir_entry *) (bh->b_data)) 586 [i_pos & (sbi->dir_per_block - 1)]; 587 if (S_ISDIR(inode->i_mode)) 588 raw_entry->size = 0; 589 else 590 raw_entry->size = cpu_to_le32(inode->i_size); 591 raw_entry->attr = fat_attr(inode); 592 raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart); 593 raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16); 594 fat_date_unix2dos(inode->i_mtime.tv_sec, &raw_entry->time, 595 &raw_entry->date, sbi->options.tz_utc); 596 if (sbi->options.isvfat) { 597 __le16 atime; 598 fat_date_unix2dos(inode->i_ctime.tv_sec, &raw_entry->ctime, 599 &raw_entry->cdate, sbi->options.tz_utc); 600 fat_date_unix2dos(inode->i_atime.tv_sec, &atime, 601 &raw_entry->adate, sbi->options.tz_utc); 602 raw_entry->ctime_cs = (inode->i_ctime.tv_sec & 1) * 100 + 603 inode->i_ctime.tv_nsec / 10000000; 604 } 605 spin_unlock(&sbi->inode_hash_lock); 606 mark_buffer_dirty(bh); 607 err = 0; 608 if (wait) 609 err = sync_dirty_buffer(bh); 610 brelse(bh); 611 return err; 612 } 613 614 int fat_sync_inode(struct inode *inode) 615 { 616 return fat_write_inode(inode, 1); 617 } 618 619 EXPORT_SYMBOL_GPL(fat_sync_inode); 620 621 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt); 622 static const struct super_operations fat_sops = { 623 .alloc_inode = fat_alloc_inode, 624 .destroy_inode = fat_destroy_inode, 625 .write_inode = fat_write_inode, 626 .delete_inode = fat_delete_inode, 627 .put_super = fat_put_super, 628 .write_super = fat_write_super, 629 .statfs = fat_statfs, 630 .clear_inode = fat_clear_inode, 631 .remount_fs = fat_remount, 632 633 .show_options = fat_show_options, 634 }; 635 636 /* 637 * a FAT file handle with fhtype 3 is 638 * 0/ i_ino - for fast, reliable lookup if still in the cache 639 * 1/ i_generation - to see if i_ino is still valid 640 * bit 0 == 0 iff directory 641 * 2/ i_pos(8-39) - if ino has changed, but still in cache 642 * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos 643 * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc 644 * 645 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum 646 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits 647 * of i_logstart is used to store the directory entry offset. 648 */ 649 650 static struct dentry *fat_fh_to_dentry(struct super_block *sb, 651 struct fid *fid, int fh_len, int fh_type) 652 { 653 struct inode *inode = NULL; 654 struct dentry *result; 655 u32 *fh = fid->raw; 656 657 if (fh_len < 5 || fh_type != 3) 658 return NULL; 659 660 inode = ilookup(sb, fh[0]); 661 if (!inode || inode->i_generation != fh[1]) { 662 if (inode) 663 iput(inode); 664 inode = NULL; 665 } 666 if (!inode) { 667 loff_t i_pos; 668 int i_logstart = fh[3] & 0x0fffffff; 669 670 i_pos = (loff_t)fh[2] << 8; 671 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28); 672 673 /* try 2 - see if i_pos is in F-d-c 674 * require i_logstart to be the same 675 * Will fail if you truncate and then re-write 676 */ 677 678 inode = fat_iget(sb, i_pos); 679 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) { 680 iput(inode); 681 inode = NULL; 682 } 683 } 684 if (!inode) { 685 /* For now, do nothing 686 * What we could do is: 687 * follow the file starting at fh[4], and record 688 * the ".." entry, and the name of the fh[2] entry. 689 * The follow the ".." file finding the next step up. 690 * This way we build a path to the root of 691 * the tree. If this works, we lookup the path and so 692 * get this inode into the cache. 693 * Finally try the fat_iget lookup again 694 * If that fails, then weare totally out of luck 695 * But all that is for another day 696 */ 697 } 698 if (!inode) 699 return ERR_PTR(-ESTALE); 700 701 702 /* now to find a dentry. 703 * If possible, get a well-connected one 704 */ 705 result = d_alloc_anon(inode); 706 if (result == NULL) { 707 iput(inode); 708 return ERR_PTR(-ENOMEM); 709 } 710 result->d_op = sb->s_root->d_op; 711 return result; 712 } 713 714 static int 715 fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable) 716 { 717 int len = *lenp; 718 struct inode *inode = de->d_inode; 719 u32 ipos_h, ipos_m, ipos_l; 720 721 if (len < 5) 722 return 255; /* no room */ 723 724 ipos_h = MSDOS_I(inode)->i_pos >> 8; 725 ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24; 726 ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28; 727 *lenp = 5; 728 fh[0] = inode->i_ino; 729 fh[1] = inode->i_generation; 730 fh[2] = ipos_h; 731 fh[3] = ipos_m | MSDOS_I(inode)->i_logstart; 732 spin_lock(&de->d_lock); 733 fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart; 734 spin_unlock(&de->d_lock); 735 return 3; 736 } 737 738 static struct dentry *fat_get_parent(struct dentry *child) 739 { 740 struct super_block *sb = child->d_sb; 741 struct buffer_head *bh; 742 struct msdos_dir_entry *de; 743 loff_t i_pos; 744 struct dentry *parent; 745 struct inode *inode; 746 int err; 747 748 lock_super(sb); 749 750 err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos); 751 if (err) { 752 parent = ERR_PTR(err); 753 goto out; 754 } 755 inode = fat_build_inode(sb, de, i_pos); 756 brelse(bh); 757 if (IS_ERR(inode)) { 758 parent = ERR_CAST(inode); 759 goto out; 760 } 761 parent = d_alloc_anon(inode); 762 if (!parent) { 763 iput(inode); 764 parent = ERR_PTR(-ENOMEM); 765 } 766 out: 767 unlock_super(sb); 768 769 return parent; 770 } 771 772 static const struct export_operations fat_export_ops = { 773 .encode_fh = fat_encode_fh, 774 .fh_to_dentry = fat_fh_to_dentry, 775 .get_parent = fat_get_parent, 776 }; 777 778 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt) 779 { 780 struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb); 781 struct fat_mount_options *opts = &sbi->options; 782 int isvfat = opts->isvfat; 783 784 if (opts->fs_uid != 0) 785 seq_printf(m, ",uid=%u", opts->fs_uid); 786 if (opts->fs_gid != 0) 787 seq_printf(m, ",gid=%u", opts->fs_gid); 788 seq_printf(m, ",fmask=%04o", opts->fs_fmask); 789 seq_printf(m, ",dmask=%04o", opts->fs_dmask); 790 if (opts->allow_utime) 791 seq_printf(m, ",allow_utime=%04o", opts->allow_utime); 792 if (sbi->nls_disk) 793 seq_printf(m, ",codepage=%s", sbi->nls_disk->charset); 794 if (isvfat) { 795 if (sbi->nls_io) 796 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset); 797 798 switch (opts->shortname) { 799 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95: 800 seq_puts(m, ",shortname=win95"); 801 break; 802 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT: 803 seq_puts(m, ",shortname=winnt"); 804 break; 805 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95: 806 seq_puts(m, ",shortname=mixed"); 807 break; 808 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95: 809 /* seq_puts(m, ",shortname=lower"); */ 810 break; 811 default: 812 seq_puts(m, ",shortname=unknown"); 813 break; 814 } 815 } 816 if (opts->name_check != 'n') 817 seq_printf(m, ",check=%c", opts->name_check); 818 if (opts->usefree) 819 seq_puts(m, ",usefree"); 820 if (opts->quiet) 821 seq_puts(m, ",quiet"); 822 if (opts->showexec) 823 seq_puts(m, ",showexec"); 824 if (opts->sys_immutable) 825 seq_puts(m, ",sys_immutable"); 826 if (!isvfat) { 827 if (opts->dotsOK) 828 seq_puts(m, ",dotsOK=yes"); 829 if (opts->nocase) 830 seq_puts(m, ",nocase"); 831 } else { 832 if (opts->utf8) 833 seq_puts(m, ",utf8"); 834 if (opts->unicode_xlate) 835 seq_puts(m, ",uni_xlate"); 836 if (!opts->numtail) 837 seq_puts(m, ",nonumtail"); 838 } 839 if (sbi->options.flush) 840 seq_puts(m, ",flush"); 841 if (opts->tz_utc) 842 seq_puts(m, ",tz=UTC"); 843 844 return 0; 845 } 846 847 enum { 848 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid, 849 Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage, 850 Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug, 851 Opt_immutable, Opt_dots, Opt_nodots, 852 Opt_charset, Opt_shortname_lower, Opt_shortname_win95, 853 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes, 854 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes, 855 Opt_obsolate, Opt_flush, Opt_tz_utc, Opt_err, 856 }; 857 858 static const match_table_t fat_tokens = { 859 {Opt_check_r, "check=relaxed"}, 860 {Opt_check_s, "check=strict"}, 861 {Opt_check_n, "check=normal"}, 862 {Opt_check_r, "check=r"}, 863 {Opt_check_s, "check=s"}, 864 {Opt_check_n, "check=n"}, 865 {Opt_uid, "uid=%u"}, 866 {Opt_gid, "gid=%u"}, 867 {Opt_umask, "umask=%o"}, 868 {Opt_dmask, "dmask=%o"}, 869 {Opt_fmask, "fmask=%o"}, 870 {Opt_allow_utime, "allow_utime=%o"}, 871 {Opt_codepage, "codepage=%u"}, 872 {Opt_usefree, "usefree"}, 873 {Opt_nocase, "nocase"}, 874 {Opt_quiet, "quiet"}, 875 {Opt_showexec, "showexec"}, 876 {Opt_debug, "debug"}, 877 {Opt_immutable, "sys_immutable"}, 878 {Opt_obsolate, "conv=binary"}, 879 {Opt_obsolate, "conv=text"}, 880 {Opt_obsolate, "conv=auto"}, 881 {Opt_obsolate, "conv=b"}, 882 {Opt_obsolate, "conv=t"}, 883 {Opt_obsolate, "conv=a"}, 884 {Opt_obsolate, "fat=%u"}, 885 {Opt_obsolate, "blocksize=%u"}, 886 {Opt_obsolate, "cvf_format=%20s"}, 887 {Opt_obsolate, "cvf_options=%100s"}, 888 {Opt_obsolate, "posix"}, 889 {Opt_flush, "flush"}, 890 {Opt_tz_utc, "tz=UTC"}, 891 {Opt_err, NULL}, 892 }; 893 static const match_table_t msdos_tokens = { 894 {Opt_nodots, "nodots"}, 895 {Opt_nodots, "dotsOK=no"}, 896 {Opt_dots, "dots"}, 897 {Opt_dots, "dotsOK=yes"}, 898 {Opt_err, NULL} 899 }; 900 static const match_table_t vfat_tokens = { 901 {Opt_charset, "iocharset=%s"}, 902 {Opt_shortname_lower, "shortname=lower"}, 903 {Opt_shortname_win95, "shortname=win95"}, 904 {Opt_shortname_winnt, "shortname=winnt"}, 905 {Opt_shortname_mixed, "shortname=mixed"}, 906 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */ 907 {Opt_utf8_no, "utf8=no"}, 908 {Opt_utf8_no, "utf8=false"}, 909 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */ 910 {Opt_utf8_yes, "utf8=yes"}, 911 {Opt_utf8_yes, "utf8=true"}, 912 {Opt_utf8_yes, "utf8"}, 913 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */ 914 {Opt_uni_xl_no, "uni_xlate=no"}, 915 {Opt_uni_xl_no, "uni_xlate=false"}, 916 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */ 917 {Opt_uni_xl_yes, "uni_xlate=yes"}, 918 {Opt_uni_xl_yes, "uni_xlate=true"}, 919 {Opt_uni_xl_yes, "uni_xlate"}, 920 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */ 921 {Opt_nonumtail_no, "nonumtail=no"}, 922 {Opt_nonumtail_no, "nonumtail=false"}, 923 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */ 924 {Opt_nonumtail_yes, "nonumtail=yes"}, 925 {Opt_nonumtail_yes, "nonumtail=true"}, 926 {Opt_nonumtail_yes, "nonumtail"}, 927 {Opt_err, NULL} 928 }; 929 930 static int parse_options(char *options, int is_vfat, int silent, int *debug, 931 struct fat_mount_options *opts) 932 { 933 char *p; 934 substring_t args[MAX_OPT_ARGS]; 935 int option; 936 char *iocharset; 937 938 opts->isvfat = is_vfat; 939 940 opts->fs_uid = current->uid; 941 opts->fs_gid = current->gid; 942 opts->fs_fmask = opts->fs_dmask = current->fs->umask; 943 opts->allow_utime = -1; 944 opts->codepage = fat_default_codepage; 945 opts->iocharset = fat_default_iocharset; 946 if (is_vfat) 947 opts->shortname = VFAT_SFN_DISPLAY_LOWER|VFAT_SFN_CREATE_WIN95; 948 else 949 opts->shortname = 0; 950 opts->name_check = 'n'; 951 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0; 952 opts->utf8 = opts->unicode_xlate = 0; 953 opts->numtail = 1; 954 opts->usefree = opts->nocase = 0; 955 opts->tz_utc = 0; 956 *debug = 0; 957 958 if (!options) 959 goto out; 960 961 while ((p = strsep(&options, ",")) != NULL) { 962 int token; 963 if (!*p) 964 continue; 965 966 token = match_token(p, fat_tokens, args); 967 if (token == Opt_err) { 968 if (is_vfat) 969 token = match_token(p, vfat_tokens, args); 970 else 971 token = match_token(p, msdos_tokens, args); 972 } 973 switch (token) { 974 case Opt_check_s: 975 opts->name_check = 's'; 976 break; 977 case Opt_check_r: 978 opts->name_check = 'r'; 979 break; 980 case Opt_check_n: 981 opts->name_check = 'n'; 982 break; 983 case Opt_usefree: 984 opts->usefree = 1; 985 break; 986 case Opt_nocase: 987 if (!is_vfat) 988 opts->nocase = 1; 989 else { 990 /* for backward compatibility */ 991 opts->shortname = VFAT_SFN_DISPLAY_WIN95 992 | VFAT_SFN_CREATE_WIN95; 993 } 994 break; 995 case Opt_quiet: 996 opts->quiet = 1; 997 break; 998 case Opt_showexec: 999 opts->showexec = 1; 1000 break; 1001 case Opt_debug: 1002 *debug = 1; 1003 break; 1004 case Opt_immutable: 1005 opts->sys_immutable = 1; 1006 break; 1007 case Opt_uid: 1008 if (match_int(&args[0], &option)) 1009 return 0; 1010 opts->fs_uid = option; 1011 break; 1012 case Opt_gid: 1013 if (match_int(&args[0], &option)) 1014 return 0; 1015 opts->fs_gid = option; 1016 break; 1017 case Opt_umask: 1018 if (match_octal(&args[0], &option)) 1019 return 0; 1020 opts->fs_fmask = opts->fs_dmask = option; 1021 break; 1022 case Opt_dmask: 1023 if (match_octal(&args[0], &option)) 1024 return 0; 1025 opts->fs_dmask = option; 1026 break; 1027 case Opt_fmask: 1028 if (match_octal(&args[0], &option)) 1029 return 0; 1030 opts->fs_fmask = option; 1031 break; 1032 case Opt_allow_utime: 1033 if (match_octal(&args[0], &option)) 1034 return 0; 1035 opts->allow_utime = option & (S_IWGRP | S_IWOTH); 1036 break; 1037 case Opt_codepage: 1038 if (match_int(&args[0], &option)) 1039 return 0; 1040 opts->codepage = option; 1041 break; 1042 case Opt_flush: 1043 opts->flush = 1; 1044 break; 1045 case Opt_tz_utc: 1046 opts->tz_utc = 1; 1047 break; 1048 1049 /* msdos specific */ 1050 case Opt_dots: 1051 opts->dotsOK = 1; 1052 break; 1053 case Opt_nodots: 1054 opts->dotsOK = 0; 1055 break; 1056 1057 /* vfat specific */ 1058 case Opt_charset: 1059 if (opts->iocharset != fat_default_iocharset) 1060 kfree(opts->iocharset); 1061 iocharset = match_strdup(&args[0]); 1062 if (!iocharset) 1063 return -ENOMEM; 1064 opts->iocharset = iocharset; 1065 break; 1066 case Opt_shortname_lower: 1067 opts->shortname = VFAT_SFN_DISPLAY_LOWER 1068 | VFAT_SFN_CREATE_WIN95; 1069 break; 1070 case Opt_shortname_win95: 1071 opts->shortname = VFAT_SFN_DISPLAY_WIN95 1072 | VFAT_SFN_CREATE_WIN95; 1073 break; 1074 case Opt_shortname_winnt: 1075 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1076 | VFAT_SFN_CREATE_WINNT; 1077 break; 1078 case Opt_shortname_mixed: 1079 opts->shortname = VFAT_SFN_DISPLAY_WINNT 1080 | VFAT_SFN_CREATE_WIN95; 1081 break; 1082 case Opt_utf8_no: /* 0 or no or false */ 1083 opts->utf8 = 0; 1084 break; 1085 case Opt_utf8_yes: /* empty or 1 or yes or true */ 1086 opts->utf8 = 1; 1087 break; 1088 case Opt_uni_xl_no: /* 0 or no or false */ 1089 opts->unicode_xlate = 0; 1090 break; 1091 case Opt_uni_xl_yes: /* empty or 1 or yes or true */ 1092 opts->unicode_xlate = 1; 1093 break; 1094 case Opt_nonumtail_no: /* 0 or no or false */ 1095 opts->numtail = 1; /* negated option */ 1096 break; 1097 case Opt_nonumtail_yes: /* empty or 1 or yes or true */ 1098 opts->numtail = 0; /* negated option */ 1099 break; 1100 1101 /* obsolete mount options */ 1102 case Opt_obsolate: 1103 printk(KERN_INFO "FAT: \"%s\" option is obsolete, " 1104 "not supported now\n", p); 1105 break; 1106 /* unknown option */ 1107 default: 1108 if (!silent) { 1109 printk(KERN_ERR 1110 "FAT: Unrecognized mount option \"%s\" " 1111 "or missing value\n", p); 1112 } 1113 return -EINVAL; 1114 } 1115 } 1116 1117 out: 1118 /* UTF-8 doesn't provide FAT semantics */ 1119 if (!strcmp(opts->iocharset, "utf8")) { 1120 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset" 1121 " for FAT filesystems, filesystem will be " 1122 "case sensitive!\n"); 1123 } 1124 1125 /* If user doesn't specify allow_utime, it's initialized from dmask. */ 1126 if (opts->allow_utime == (unsigned short)-1) 1127 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH); 1128 if (opts->unicode_xlate) 1129 opts->utf8 = 0; 1130 1131 return 0; 1132 } 1133 1134 static int fat_read_root(struct inode *inode) 1135 { 1136 struct super_block *sb = inode->i_sb; 1137 struct msdos_sb_info *sbi = MSDOS_SB(sb); 1138 int error; 1139 1140 MSDOS_I(inode)->i_pos = 0; 1141 inode->i_uid = sbi->options.fs_uid; 1142 inode->i_gid = sbi->options.fs_gid; 1143 inode->i_version++; 1144 inode->i_generation = 0; 1145 inode->i_mode = (S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR; 1146 inode->i_op = sbi->dir_ops; 1147 inode->i_fop = &fat_dir_operations; 1148 if (sbi->fat_bits == 32) { 1149 MSDOS_I(inode)->i_start = sbi->root_cluster; 1150 error = fat_calc_dir_size(inode); 1151 if (error < 0) 1152 return error; 1153 } else { 1154 MSDOS_I(inode)->i_start = 0; 1155 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry); 1156 } 1157 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1)) 1158 & ~((loff_t)sbi->cluster_size - 1)) >> 9; 1159 MSDOS_I(inode)->i_logstart = 0; 1160 MSDOS_I(inode)->mmu_private = inode->i_size; 1161 1162 MSDOS_I(inode)->i_attrs = ATTR_NONE; 1163 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0; 1164 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0; 1165 inode->i_nlink = fat_subdirs(inode)+2; 1166 1167 return 0; 1168 } 1169 1170 /* 1171 * Read the super block of an MS-DOS FS. 1172 */ 1173 int fat_fill_super(struct super_block *sb, void *data, int silent, 1174 const struct inode_operations *fs_dir_inode_ops, int isvfat) 1175 { 1176 struct inode *root_inode = NULL; 1177 struct buffer_head *bh; 1178 struct fat_boot_sector *b; 1179 struct msdos_sb_info *sbi; 1180 u16 logical_sector_size; 1181 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors; 1182 int debug; 1183 unsigned int media; 1184 long error; 1185 char buf[50]; 1186 1187 /* 1188 * GFP_KERNEL is ok here, because while we do hold the 1189 * supeblock lock, memory pressure can't call back into 1190 * the filesystem, since we're only just about to mount 1191 * it and have no inodes etc active! 1192 */ 1193 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL); 1194 if (!sbi) 1195 return -ENOMEM; 1196 sb->s_fs_info = sbi; 1197 1198 sb->s_flags |= MS_NODIRATIME; 1199 sb->s_magic = MSDOS_SUPER_MAGIC; 1200 sb->s_op = &fat_sops; 1201 sb->s_export_op = &fat_export_ops; 1202 sbi->dir_ops = fs_dir_inode_ops; 1203 1204 error = parse_options(data, isvfat, silent, &debug, &sbi->options); 1205 if (error) 1206 goto out_fail; 1207 1208 error = -EIO; 1209 sb_min_blocksize(sb, 512); 1210 bh = sb_bread(sb, 0); 1211 if (bh == NULL) { 1212 printk(KERN_ERR "FAT: unable to read boot sector\n"); 1213 goto out_fail; 1214 } 1215 1216 b = (struct fat_boot_sector *) bh->b_data; 1217 if (!b->reserved) { 1218 if (!silent) 1219 printk(KERN_ERR "FAT: bogus number of reserved sectors\n"); 1220 brelse(bh); 1221 goto out_invalid; 1222 } 1223 if (!b->fats) { 1224 if (!silent) 1225 printk(KERN_ERR "FAT: bogus number of FAT structure\n"); 1226 brelse(bh); 1227 goto out_invalid; 1228 } 1229 1230 /* 1231 * Earlier we checked here that b->secs_track and b->head are nonzero, 1232 * but it turns out valid FAT filesystems can have zero there. 1233 */ 1234 1235 media = b->media; 1236 if (!fat_valid_media(media)) { 1237 if (!silent) 1238 printk(KERN_ERR "FAT: invalid media value (0x%02x)\n", 1239 media); 1240 brelse(bh); 1241 goto out_invalid; 1242 } 1243 logical_sector_size = get_unaligned_le16(&b->sector_size); 1244 if (!is_power_of_2(logical_sector_size) 1245 || (logical_sector_size < 512) 1246 || (logical_sector_size > 4096)) { 1247 if (!silent) 1248 printk(KERN_ERR "FAT: bogus logical sector size %u\n", 1249 logical_sector_size); 1250 brelse(bh); 1251 goto out_invalid; 1252 } 1253 sbi->sec_per_clus = b->sec_per_clus; 1254 if (!is_power_of_2(sbi->sec_per_clus)) { 1255 if (!silent) 1256 printk(KERN_ERR "FAT: bogus sectors per cluster %u\n", 1257 sbi->sec_per_clus); 1258 brelse(bh); 1259 goto out_invalid; 1260 } 1261 1262 if (logical_sector_size < sb->s_blocksize) { 1263 printk(KERN_ERR "FAT: logical sector size too small for device" 1264 " (logical sector size = %u)\n", logical_sector_size); 1265 brelse(bh); 1266 goto out_fail; 1267 } 1268 if (logical_sector_size > sb->s_blocksize) { 1269 brelse(bh); 1270 1271 if (!sb_set_blocksize(sb, logical_sector_size)) { 1272 printk(KERN_ERR "FAT: unable to set blocksize %u\n", 1273 logical_sector_size); 1274 goto out_fail; 1275 } 1276 bh = sb_bread(sb, 0); 1277 if (bh == NULL) { 1278 printk(KERN_ERR "FAT: unable to read boot sector" 1279 " (logical sector size = %lu)\n", 1280 sb->s_blocksize); 1281 goto out_fail; 1282 } 1283 b = (struct fat_boot_sector *) bh->b_data; 1284 } 1285 1286 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus; 1287 sbi->cluster_bits = ffs(sbi->cluster_size) - 1; 1288 sbi->fats = b->fats; 1289 sbi->fat_bits = 0; /* Don't know yet */ 1290 sbi->fat_start = le16_to_cpu(b->reserved); 1291 sbi->fat_length = le16_to_cpu(b->fat_length); 1292 sbi->root_cluster = 0; 1293 sbi->free_clusters = -1; /* Don't know yet */ 1294 sbi->free_clus_valid = 0; 1295 sbi->prev_free = FAT_START_ENT; 1296 1297 if (!sbi->fat_length && b->fat32_length) { 1298 struct fat_boot_fsinfo *fsinfo; 1299 struct buffer_head *fsinfo_bh; 1300 1301 /* Must be FAT32 */ 1302 sbi->fat_bits = 32; 1303 sbi->fat_length = le32_to_cpu(b->fat32_length); 1304 sbi->root_cluster = le32_to_cpu(b->root_cluster); 1305 1306 sb->s_maxbytes = 0xffffffff; 1307 1308 /* MC - if info_sector is 0, don't multiply by 0 */ 1309 sbi->fsinfo_sector = le16_to_cpu(b->info_sector); 1310 if (sbi->fsinfo_sector == 0) 1311 sbi->fsinfo_sector = 1; 1312 1313 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector); 1314 if (fsinfo_bh == NULL) { 1315 printk(KERN_ERR "FAT: bread failed, FSINFO block" 1316 " (sector = %lu)\n", sbi->fsinfo_sector); 1317 brelse(bh); 1318 goto out_fail; 1319 } 1320 1321 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data; 1322 if (!IS_FSINFO(fsinfo)) { 1323 printk(KERN_WARNING "FAT: Invalid FSINFO signature: " 1324 "0x%08x, 0x%08x (sector = %lu)\n", 1325 le32_to_cpu(fsinfo->signature1), 1326 le32_to_cpu(fsinfo->signature2), 1327 sbi->fsinfo_sector); 1328 } else { 1329 if (sbi->options.usefree) 1330 sbi->free_clus_valid = 1; 1331 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters); 1332 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster); 1333 } 1334 1335 brelse(fsinfo_bh); 1336 } 1337 1338 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry); 1339 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1; 1340 1341 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length; 1342 sbi->dir_entries = get_unaligned_le16(&b->dir_entries); 1343 if (sbi->dir_entries & (sbi->dir_per_block - 1)) { 1344 if (!silent) 1345 printk(KERN_ERR "FAT: bogus directroy-entries per block" 1346 " (%u)\n", sbi->dir_entries); 1347 brelse(bh); 1348 goto out_invalid; 1349 } 1350 1351 rootdir_sectors = sbi->dir_entries 1352 * sizeof(struct msdos_dir_entry) / sb->s_blocksize; 1353 sbi->data_start = sbi->dir_start + rootdir_sectors; 1354 total_sectors = get_unaligned_le16(&b->sectors); 1355 if (total_sectors == 0) 1356 total_sectors = le32_to_cpu(b->total_sect); 1357 1358 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus; 1359 1360 if (sbi->fat_bits != 32) 1361 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12; 1362 1363 /* check that FAT table does not overflow */ 1364 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits; 1365 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT); 1366 if (total_clusters > MAX_FAT(sb)) { 1367 if (!silent) 1368 printk(KERN_ERR "FAT: count of clusters too big (%u)\n", 1369 total_clusters); 1370 brelse(bh); 1371 goto out_invalid; 1372 } 1373 1374 sbi->max_cluster = total_clusters + FAT_START_ENT; 1375 /* check the free_clusters, it's not necessarily correct */ 1376 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters) 1377 sbi->free_clusters = -1; 1378 /* check the prev_free, it's not necessarily correct */ 1379 sbi->prev_free %= sbi->max_cluster; 1380 if (sbi->prev_free < FAT_START_ENT) 1381 sbi->prev_free = FAT_START_ENT; 1382 1383 brelse(bh); 1384 1385 /* set up enough so that it can read an inode */ 1386 fat_hash_init(sb); 1387 fat_ent_access_init(sb); 1388 1389 /* 1390 * The low byte of FAT's first entry must have same value with 1391 * media-field. But in real world, too many devices is 1392 * writing wrong value. So, removed that validity check. 1393 * 1394 * if (FAT_FIRST_ENT(sb, media) != first) 1395 */ 1396 1397 error = -EINVAL; 1398 sprintf(buf, "cp%d", sbi->options.codepage); 1399 sbi->nls_disk = load_nls(buf); 1400 if (!sbi->nls_disk) { 1401 printk(KERN_ERR "FAT: codepage %s not found\n", buf); 1402 goto out_fail; 1403 } 1404 1405 /* FIXME: utf8 is using iocharset for upper/lower conversion */ 1406 if (sbi->options.isvfat) { 1407 sbi->nls_io = load_nls(sbi->options.iocharset); 1408 if (!sbi->nls_io) { 1409 printk(KERN_ERR "FAT: IO charset %s not found\n", 1410 sbi->options.iocharset); 1411 goto out_fail; 1412 } 1413 } 1414 1415 error = -ENOMEM; 1416 root_inode = new_inode(sb); 1417 if (!root_inode) 1418 goto out_fail; 1419 root_inode->i_ino = MSDOS_ROOT_INO; 1420 root_inode->i_version = 1; 1421 error = fat_read_root(root_inode); 1422 if (error < 0) 1423 goto out_fail; 1424 error = -ENOMEM; 1425 insert_inode_hash(root_inode); 1426 sb->s_root = d_alloc_root(root_inode); 1427 if (!sb->s_root) { 1428 printk(KERN_ERR "FAT: get root inode failed\n"); 1429 goto out_fail; 1430 } 1431 1432 return 0; 1433 1434 out_invalid: 1435 error = -EINVAL; 1436 if (!silent) 1437 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem" 1438 " on dev %s.\n", sb->s_id); 1439 1440 out_fail: 1441 if (root_inode) 1442 iput(root_inode); 1443 if (sbi->nls_io) 1444 unload_nls(sbi->nls_io); 1445 if (sbi->nls_disk) 1446 unload_nls(sbi->nls_disk); 1447 if (sbi->options.iocharset != fat_default_iocharset) 1448 kfree(sbi->options.iocharset); 1449 sb->s_fs_info = NULL; 1450 kfree(sbi); 1451 return error; 1452 } 1453 1454 EXPORT_SYMBOL_GPL(fat_fill_super); 1455 1456 /* 1457 * helper function for fat_flush_inodes. This writes both the inode 1458 * and the file data blocks, waiting for in flight data blocks before 1459 * the start of the call. It does not wait for any io started 1460 * during the call 1461 */ 1462 static int writeback_inode(struct inode *inode) 1463 { 1464 1465 int ret; 1466 struct address_space *mapping = inode->i_mapping; 1467 struct writeback_control wbc = { 1468 .sync_mode = WB_SYNC_NONE, 1469 .nr_to_write = 0, 1470 }; 1471 /* if we used WB_SYNC_ALL, sync_inode waits for the io for the 1472 * inode to finish. So WB_SYNC_NONE is sent down to sync_inode 1473 * and filemap_fdatawrite is used for the data blocks 1474 */ 1475 ret = sync_inode(inode, &wbc); 1476 if (!ret) 1477 ret = filemap_fdatawrite(mapping); 1478 return ret; 1479 } 1480 1481 /* 1482 * write data and metadata corresponding to i1 and i2. The io is 1483 * started but we do not wait for any of it to finish. 1484 * 1485 * filemap_flush is used for the block device, so if there is a dirty 1486 * page for a block already in flight, we will not wait and start the 1487 * io over again 1488 */ 1489 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2) 1490 { 1491 int ret = 0; 1492 if (!MSDOS_SB(sb)->options.flush) 1493 return 0; 1494 if (i1) 1495 ret = writeback_inode(i1); 1496 if (!ret && i2) 1497 ret = writeback_inode(i2); 1498 if (!ret) { 1499 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping; 1500 ret = filemap_flush(mapping); 1501 } 1502 return ret; 1503 } 1504 EXPORT_SYMBOL_GPL(fat_flush_inodes); 1505 1506 static int __init init_fat_fs(void) 1507 { 1508 int err; 1509 1510 err = fat_cache_init(); 1511 if (err) 1512 return err; 1513 1514 err = fat_init_inodecache(); 1515 if (err) 1516 goto failed; 1517 1518 return 0; 1519 1520 failed: 1521 fat_cache_destroy(); 1522 return err; 1523 } 1524 1525 static void __exit exit_fat_fs(void) 1526 { 1527 fat_cache_destroy(); 1528 fat_destroy_inodecache(); 1529 } 1530 1531 module_init(init_fat_fs) 1532 module_exit(exit_fat_fs) 1533 1534 MODULE_LICENSE("GPL"); 1535