inode.c 41 KB

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