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