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[CPUFREQ] Misc cleanups in ondemand.
[linux-2.6/next.git] / fs / fat / inode.c
blob31b7174176ba76798284286e8f6767419cef7e12
1 /*
2 * linux/fs/fat/inode.c
3 *
4 * Written 1992,1993 by Werner Almesberger
5 * VFAT extensions by Gordon Chaffee, merged with msdos fs by Henrik Storner
6 * Rewritten for the constant inumbers support by Al Viro
7 *
8 * Fixes:
9 *
10 * Max Cohan: Fixed invalid FSINFO offset when info_sector is 0
11 */
12
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/time.h>
16 #include <linux/slab.h>
17 #include <linux/smp_lock.h>
18 #include <linux/seq_file.h>
19 #include <linux/msdos_fs.h>
20 #include <linux/pagemap.h>
21 #include <linux/mpage.h>
22 #include <linux/buffer_head.h>
23 #include <linux/mount.h>
24 #include <linux/vfs.h>
25 #include <linux/parser.h>
26 #include <linux/uio.h>
27 #include <asm/unaligned.h>
28
29 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET
30 /* if user don't select VFAT, this is undefined. */
31 #define CONFIG_FAT_DEFAULT_IOCHARSET ""
32 #endif
33
34 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
35 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
36
37
38 static int fat_add_cluster(struct inode *inode)
39 {
40 int err, cluster;
41
42 err = fat_alloc_clusters(inode, &cluster, 1);
43 if (err)
44 return err;
45 /* FIXME: this cluster should be added after data of this
46 * cluster is writed */
47 err = fat_chain_add(inode, cluster, 1);
48 if (err)
49 fat_free_clusters(inode, cluster);
50 return err;
51 }
52
53 static int __fat_get_blocks(struct inode *inode, sector_t iblock,
54 unsigned long *max_blocks,
55 struct buffer_head *bh_result, int create)
56 {
57 struct super_block *sb = inode->i_sb;
58 struct msdos_sb_info *sbi = MSDOS_SB(sb);
59 sector_t phys;
60 unsigned long mapped_blocks;
61 int err, offset;
62
63 err = fat_bmap(inode, iblock, &phys, &mapped_blocks);
64 if (err)
65 return err;
66 if (phys) {
67 map_bh(bh_result, sb, phys);
68 *max_blocks = min(mapped_blocks, *max_blocks);
69 return 0;
70 }
71 if (!create)
72 return 0;
73
74 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
75 fat_fs_panic(sb, "corrupted file size (i_pos %lld, %lld)",
76 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
77 return -EIO;
78 }
79
80 offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
81 if (!offset) {
82 /* TODO: multiple cluster allocation would be desirable. */
83 err = fat_add_cluster(inode);
84 if (err)
85 return err;
86 }
87 /* available blocks on this cluster */
88 mapped_blocks = sbi->sec_per_clus - offset;
89
90 *max_blocks = min(mapped_blocks, *max_blocks);
91 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
92
93 err = fat_bmap(inode, iblock, &phys, &mapped_blocks);
94 if (err)
95 return err;
96 BUG_ON(!phys);
97 BUG_ON(*max_blocks != mapped_blocks);
98 set_buffer_new(bh_result);
99 map_bh(bh_result, sb, phys);
100 return 0;
101 }
102
103 static int fat_get_blocks(struct inode *inode, sector_t iblock,
104 struct buffer_head *bh_result, int create)
105 {
106 struct super_block *sb = inode->i_sb;
107 int err;
108 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
109
110 err = __fat_get_blocks(inode, iblock, &max_blocks, bh_result, create);
111 if (err)
112 return err;
113 bh_result->b_size = max_blocks << sb->s_blocksize_bits;
114 return 0;
115 }
116
117 static int fat_get_block(struct inode *inode, sector_t iblock,
118 struct buffer_head *bh_result, int create)
119 {
120 unsigned long max_blocks = 1;
121 return __fat_get_blocks(inode, iblock, &max_blocks, bh_result, create);
122 }
123
124 static int fat_writepage(struct page *page, struct writeback_control *wbc)
125 {
126 return block_write_full_page(page, fat_get_block, wbc);
127 }
128
129 static int fat_writepages(struct address_space *mapping,
130 struct writeback_control *wbc)
131 {
132 return mpage_writepages(mapping, wbc, fat_get_block);
133 }
134
135 static int fat_readpage(struct file *file, struct page *page)
136 {
137 return mpage_readpage(page, fat_get_block);
138 }
139
140 static int fat_readpages(struct file *file, struct address_space *mapping,
141 struct list_head *pages, unsigned nr_pages)
142 {
143 return mpage_readpages(mapping, pages, nr_pages, fat_get_block);
144 }
145
146 static int fat_prepare_write(struct file *file, struct page *page,
147 unsigned from, unsigned to)
148 {
149 return cont_prepare_write(page, from, to, fat_get_block,
150 &MSDOS_I(page->mapping->host)->mmu_private);
151 }
152
153 static int fat_commit_write(struct file *file, struct page *page,
154 unsigned from, unsigned to)
155 {
156 struct inode *inode = page->mapping->host;
157 int err = generic_commit_write(file, page, from, to);
158 if (!err && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
159 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
160 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
161 mark_inode_dirty(inode);
162 }
163 return err;
164 }
165
166 static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
167 const struct iovec *iov,
168 loff_t offset, unsigned long nr_segs)
169 {
170 struct file *file = iocb->ki_filp;
171 struct inode *inode = file->f_mapping->host;
172
173 if (rw == WRITE) {
174 /*
175 * FIXME: blockdev_direct_IO() doesn't use ->prepare_write(),
176 * so we need to update the ->mmu_private to block boundary.
177 *
178 * But we must fill the remaining area or hole by nul for
179 * updating ->mmu_private.
180 */
181 loff_t size = offset + iov_length(iov, nr_segs);
182 if (MSDOS_I(inode)->mmu_private < size)
183 return -EINVAL;
184 }
185
186 /*
187 * FAT need to use the DIO_LOCKING for avoiding the race
188 * condition of fat_get_block() and ->truncate().
189 */
190 return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
191 offset, nr_segs, fat_get_blocks, NULL);
192 }
193
194 static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
195 {
196 return generic_block_bmap(mapping, block, fat_get_block);
197 }
198
199 static const struct address_space_operations fat_aops = {
200 .readpage = fat_readpage,
201 .readpages = fat_readpages,
202 .writepage = fat_writepage,
203 .writepages = fat_writepages,
204 .sync_page = block_sync_page,
205 .prepare_write = fat_prepare_write,
206 .commit_write = fat_commit_write,
207 .direct_IO = fat_direct_IO,
208 .bmap = _fat_bmap
209 };
210
211 /*
212 * New FAT inode stuff. We do the following:
213 * a) i_ino is constant and has nothing with on-disk location.
214 * b) FAT manages its own cache of directory entries.
215 * c) *This* cache is indexed by on-disk location.
216 * d) inode has an associated directory entry, all right, but
217 * it may be unhashed.
218 * e) currently entries are stored within struct inode. That should
219 * change.
220 * f) we deal with races in the following way:
221 * 1. readdir() and lookup() do FAT-dir-cache lookup.
222 * 2. rename() unhashes the F-d-c entry and rehashes it in
223 * a new place.
224 * 3. unlink() and rmdir() unhash F-d-c entry.
225 * 4. fat_write_inode() checks whether the thing is unhashed.
226 * If it is we silently return. If it isn't we do bread(),
227 * check if the location is still valid and retry if it
228 * isn't. Otherwise we do changes.
229 * 5. Spinlock is used to protect hash/unhash/location check/lookup
230 * 6. fat_clear_inode() unhashes the F-d-c entry.
231 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry
232 * and consider negative result as cache miss.
233 */
234
235 static void fat_hash_init(struct super_block *sb)
236 {
237 struct msdos_sb_info *sbi = MSDOS_SB(sb);
238 int i;
239
240 spin_lock_init(&sbi->inode_hash_lock);
241 for (i = 0; i < FAT_HASH_SIZE; i++)
242 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
243 }
244
245 static inline unsigned long fat_hash(struct super_block *sb, loff_t i_pos)
246 {
247 unsigned long tmp = (unsigned long)i_pos | (unsigned long) sb;
248 tmp = tmp + (tmp >> FAT_HASH_BITS) + (tmp >> FAT_HASH_BITS * 2);
249 return tmp & FAT_HASH_MASK;
250 }
251
252 void fat_attach(struct inode *inode, loff_t i_pos)
253 {
254 struct super_block *sb = inode->i_sb;
255 struct msdos_sb_info *sbi = MSDOS_SB(sb);
256
257 spin_lock(&sbi->inode_hash_lock);
258 MSDOS_I(inode)->i_pos = i_pos;
259 hlist_add_head(&MSDOS_I(inode)->i_fat_hash,
260 sbi->inode_hashtable + fat_hash(sb, i_pos));
261 spin_unlock(&sbi->inode_hash_lock);
262 }
263
264 EXPORT_SYMBOL_GPL(fat_attach);
265
266 void fat_detach(struct inode *inode)
267 {
268 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
269 spin_lock(&sbi->inode_hash_lock);
270 MSDOS_I(inode)->i_pos = 0;
271 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
272 spin_unlock(&sbi->inode_hash_lock);
273 }
274
275 EXPORT_SYMBOL_GPL(fat_detach);
276
277 struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
278 {
279 struct msdos_sb_info *sbi = MSDOS_SB(sb);
280 struct hlist_head *head = sbi->inode_hashtable + fat_hash(sb, i_pos);
281 struct hlist_node *_p;
282 struct msdos_inode_info *i;
283 struct inode *inode = NULL;
284
285 spin_lock(&sbi->inode_hash_lock);
286 hlist_for_each_entry(i, _p, head, i_fat_hash) {
287 BUG_ON(i->vfs_inode.i_sb != sb);
288 if (i->i_pos != i_pos)
289 continue;
290 inode = igrab(&i->vfs_inode);
291 if (inode)
292 break;
293 }
294 spin_unlock(&sbi->inode_hash_lock);
295 return inode;
296 }
297
298 static int is_exec(unsigned char *extension)
299 {
300 unsigned char *exe_extensions = "EXECOMBAT", *walk;
301
302 for (walk = exe_extensions; *walk; walk += 3)
303 if (!strncmp(extension, walk, 3))
304 return 1;
305 return 0;
306 }
307
308 static int fat_calc_dir_size(struct inode *inode)
309 {
310 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
311 int ret, fclus, dclus;
312
313 inode->i_size = 0;
314 if (MSDOS_I(inode)->i_start == 0)
315 return 0;
316
317 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
318 if (ret < 0)
319 return ret;
320 inode->i_size = (fclus + 1) << sbi->cluster_bits;
321
322 return 0;
323 }
324
325 /* doesn't deal with root inode */
326 static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
327 {
328 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
329 int error;
330
331 MSDOS_I(inode)->i_pos = 0;
332 inode->i_uid = sbi->options.fs_uid;
333 inode->i_gid = sbi->options.fs_gid;
334 inode->i_version++;
335 inode->i_generation = get_seconds();
336
337 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
338 inode->i_generation &= ~1;
339 inode->i_mode = MSDOS_MKMODE(de->attr,
340 S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR;
341 inode->i_op = sbi->dir_ops;
342 inode->i_fop = &fat_dir_operations;
343
344 MSDOS_I(inode)->i_start = le16_to_cpu(de->start);
345 if (sbi->fat_bits == 32)
346 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16);
347
348 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
349 error = fat_calc_dir_size(inode);
350 if (error < 0)
351 return error;
352 MSDOS_I(inode)->mmu_private = inode->i_size;
353
354 inode->i_nlink = fat_subdirs(inode);
355 } else { /* not a directory */
356 inode->i_generation |= 1;
357 inode->i_mode = MSDOS_MKMODE(de->attr,
358 ((sbi->options.showexec &&
359 !is_exec(de->ext))
360 ? S_IRUGO|S_IWUGO : S_IRWXUGO)
361 & ~sbi->options.fs_fmask) | S_IFREG;
362 MSDOS_I(inode)->i_start = le16_to_cpu(de->start);
363 if (sbi->fat_bits == 32)
364 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16);
365
366 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
367 inode->i_size = le32_to_cpu(de->size);
368 inode->i_op = &fat_file_inode_operations;
369 inode->i_fop = &fat_file_operations;
370 inode->i_mapping->a_ops = &fat_aops;
371 MSDOS_I(inode)->mmu_private = inode->i_size;
372 }
373 if (de->attr & ATTR_SYS) {
374 if (sbi->options.sys_immutable)
375 inode->i_flags |= S_IMMUTABLE;
376 }
377 MSDOS_I(inode)->i_attrs = de->attr & ATTR_UNUSED;
378 /* this is as close to the truth as we can get ... */
379 inode->i_blksize = sbi->cluster_size;
380 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
381 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
382 inode->i_mtime.tv_sec =
383 date_dos2unix(le16_to_cpu(de->time), le16_to_cpu(de->date));
384 inode->i_mtime.tv_nsec = 0;
385 if (sbi->options.isvfat) {
386 int secs = de->ctime_cs / 100;
387 int csecs = de->ctime_cs % 100;
388 inode->i_ctime.tv_sec =
389 date_dos2unix(le16_to_cpu(de->ctime),
390 le16_to_cpu(de->cdate)) + secs;
391 inode->i_ctime.tv_nsec = csecs * 10000000;
392 inode->i_atime.tv_sec =
393 date_dos2unix(le16_to_cpu(0), le16_to_cpu(de->adate));
394 inode->i_atime.tv_nsec = 0;
395 } else
396 inode->i_ctime = inode->i_atime = inode->i_mtime;
397
398 return 0;
399 }
400
401 struct inode *fat_build_inode(struct super_block *sb,
402 struct msdos_dir_entry *de, loff_t i_pos)
403 {
404 struct inode *inode;
405 int err;
406
407 inode = fat_iget(sb, i_pos);
408 if (inode)
409 goto out;
410 inode = new_inode(sb);
411 if (!inode) {
412 inode = ERR_PTR(-ENOMEM);
413 goto out;
414 }
415 inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
416 inode->i_version = 1;
417 err = fat_fill_inode(inode, de);
418 if (err) {
419 iput(inode);
420 inode = ERR_PTR(err);
421 goto out;
422 }
423 fat_attach(inode, i_pos);
424 insert_inode_hash(inode);
425 out:
426 return inode;
427 }
428
429 EXPORT_SYMBOL_GPL(fat_build_inode);
430
431 static void fat_delete_inode(struct inode *inode)
432 {
433 truncate_inode_pages(&inode->i_data, 0);
434
435 if (!is_bad_inode(inode)) {
436 inode->i_size = 0;
437 fat_truncate(inode);
438 }
439 clear_inode(inode);
440 }
441
442 static void fat_clear_inode(struct inode *inode)
443 {
444 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
445
446 if (is_bad_inode(inode))
447 return;
448 lock_kernel();
449 spin_lock(&sbi->inode_hash_lock);
450 fat_cache_inval_inode(inode);
451 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
452 spin_unlock(&sbi->inode_hash_lock);
453 unlock_kernel();
454 }
455
456 static void fat_write_super(struct super_block *sb)
457 {
458 sb->s_dirt = 0;
459
460 if (!(sb->s_flags & MS_RDONLY))
461 fat_clusters_flush(sb);
462 }
463
464 static void fat_put_super(struct super_block *sb)
465 {
466 struct msdos_sb_info *sbi = MSDOS_SB(sb);
467
468 if (sbi->nls_disk) {
469 unload_nls(sbi->nls_disk);
470 sbi->nls_disk = NULL;
471 sbi->options.codepage = fat_default_codepage;
472 }
473 if (sbi->nls_io) {
474 unload_nls(sbi->nls_io);
475 sbi->nls_io = NULL;
476 }
477 if (sbi->options.iocharset != fat_default_iocharset) {
478 kfree(sbi->options.iocharset);
479 sbi->options.iocharset = fat_default_iocharset;
480 }
481
482 sb->s_fs_info = NULL;
483 kfree(sbi);
484 }
485
486 static kmem_cache_t *fat_inode_cachep;
487
488 static struct inode *fat_alloc_inode(struct super_block *sb)
489 {
490 struct msdos_inode_info *ei;
491 ei = kmem_cache_alloc(fat_inode_cachep, SLAB_KERNEL);
492 if (!ei)
493 return NULL;
494 return &ei->vfs_inode;
495 }
496
497 static void fat_destroy_inode(struct inode *inode)
498 {
499 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
500 }
501
502 static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
503 {
504 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
505
506 if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
507 SLAB_CTOR_CONSTRUCTOR) {
508 spin_lock_init(&ei->cache_lru_lock);
509 ei->nr_caches = 0;
510 ei->cache_valid_id = FAT_CACHE_VALID + 1;
511 INIT_LIST_HEAD(&ei->cache_lru);
512 INIT_HLIST_NODE(&ei->i_fat_hash);
513 inode_init_once(&ei->vfs_inode);
514 }
515 }
516
517 static int __init fat_init_inodecache(void)
518 {
519 fat_inode_cachep = kmem_cache_create("fat_inode_cache",
520 sizeof(struct msdos_inode_info),
521 0, (SLAB_RECLAIM_ACCOUNT|
522 SLAB_MEM_SPREAD),
523 init_once, NULL);
524 if (fat_inode_cachep == NULL)
525 return -ENOMEM;
526 return 0;
527 }
528
529 static void __exit fat_destroy_inodecache(void)
530 {
531 if (kmem_cache_destroy(fat_inode_cachep))
532 printk(KERN_INFO "fat_inode_cache: not all structures were freed\n");
533 }
534
535 static int fat_remount(struct super_block *sb, int *flags, char *data)
536 {
537 struct msdos_sb_info *sbi = MSDOS_SB(sb);
538 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME);
539 return 0;
540 }
541
542 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
543 {
544 struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
545
546 /* If the count of free cluster is still unknown, counts it here. */
547 if (sbi->free_clusters == -1) {
548 int err = fat_count_free_clusters(dentry->d_sb);
549 if (err)
550 return err;
551 }
552
553 buf->f_type = dentry->d_sb->s_magic;
554 buf->f_bsize = sbi->cluster_size;
555 buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
556 buf->f_bfree = sbi->free_clusters;
557 buf->f_bavail = sbi->free_clusters;
558 buf->f_namelen = sbi->options.isvfat ? 260 : 12;
559
560 return 0;
561 }
562
563 static int fat_write_inode(struct inode *inode, int wait)
564 {
565 struct super_block *sb = inode->i_sb;
566 struct msdos_sb_info *sbi = MSDOS_SB(sb);
567 struct buffer_head *bh;
568 struct msdos_dir_entry *raw_entry;
569 loff_t i_pos;
570 int err = 0;
571
572 retry:
573 i_pos = MSDOS_I(inode)->i_pos;
574 if (inode->i_ino == MSDOS_ROOT_INO || !i_pos)
575 return 0;
576
577 lock_kernel();
578 bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits);
579 if (!bh) {
580 printk(KERN_ERR "FAT: unable to read inode block "
581 "for updating (i_pos %lld)\n", i_pos);
582 err = -EIO;
583 goto out;
584 }
585 spin_lock(&sbi->inode_hash_lock);
586 if (i_pos != MSDOS_I(inode)->i_pos) {
587 spin_unlock(&sbi->inode_hash_lock);
588 brelse(bh);
589 unlock_kernel();
590 goto retry;
591 }
592
593 raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
594 [i_pos & (sbi->dir_per_block - 1)];
595 if (S_ISDIR(inode->i_mode))
596 raw_entry->size = 0;
597 else
598 raw_entry->size = cpu_to_le32(inode->i_size);
599 raw_entry->attr = fat_attr(inode);
600 raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart);
601 raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16);
602 fat_date_unix2dos(inode->i_mtime.tv_sec, &raw_entry->time, &raw_entry->date);
603 if (sbi->options.isvfat) {
604 __le16 atime;
605 fat_date_unix2dos(inode->i_ctime.tv_sec,&raw_entry->ctime,&raw_entry->cdate);
606 fat_date_unix2dos(inode->i_atime.tv_sec,&atime,&raw_entry->adate);
607 raw_entry->ctime_cs = (inode->i_ctime.tv_sec & 1) * 100 +
608 inode->i_ctime.tv_nsec / 10000000;
609 }
610 spin_unlock(&sbi->inode_hash_lock);
611 mark_buffer_dirty(bh);
612 if (wait)
613 err = sync_dirty_buffer(bh);
614 brelse(bh);
615 out:
616 unlock_kernel();
617 return err;
618 }
619
620 int fat_sync_inode(struct inode *inode)
621 {
622 return fat_write_inode(inode, 1);
623 }
624
625 EXPORT_SYMBOL_GPL(fat_sync_inode);
626
627 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt);
628 static struct super_operations fat_sops = {
629 .alloc_inode = fat_alloc_inode,
630 .destroy_inode = fat_destroy_inode,
631 .write_inode = fat_write_inode,
632 .delete_inode = fat_delete_inode,
633 .put_super = fat_put_super,
634 .write_super = fat_write_super,
635 .statfs = fat_statfs,
636 .clear_inode = fat_clear_inode,
637 .remount_fs = fat_remount,
638
639 .read_inode = make_bad_inode,
640
641 .show_options = fat_show_options,
642 };
643
644 /*
645 * a FAT file handle with fhtype 3 is
646 * 0/ i_ino - for fast, reliable lookup if still in the cache
647 * 1/ i_generation - to see if i_ino is still valid
648 * bit 0 == 0 iff directory
649 * 2/ i_pos(8-39) - if ino has changed, but still in cache
650 * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos
651 * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc
652 *
653 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum
654 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits
655 * of i_logstart is used to store the directory entry offset.
656 */
657
658 static struct dentry *
659 fat_decode_fh(struct super_block *sb, __u32 *fh, int len, int fhtype,
660 int (*acceptable)(void *context, struct dentry *de),
661 void *context)
662 {
663 if (fhtype != 3)
664 return ERR_PTR(-ESTALE);
665 if (len < 5)
666 return ERR_PTR(-ESTALE);
667
668 return sb->s_export_op->find_exported_dentry(sb, fh, NULL, acceptable, context);
669 }
670
671 static struct dentry *fat_get_dentry(struct super_block *sb, void *inump)
672 {
673 struct inode *inode = NULL;
674 struct dentry *result;
675 __u32 *fh = inump;
676
677 inode = iget(sb, fh[0]);
678 if (!inode || is_bad_inode(inode) || inode->i_generation != fh[1]) {
679 if (inode)
680 iput(inode);
681 inode = NULL;
682 }
683 if (!inode) {
684 loff_t i_pos;
685 int i_logstart = fh[3] & 0x0fffffff;
686
687 i_pos = (loff_t)fh[2] << 8;
688 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28);
689
690 /* try 2 - see if i_pos is in F-d-c
691 * require i_logstart to be the same
692 * Will fail if you truncate and then re-write
693 */
694
695 inode = fat_iget(sb, i_pos);
696 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) {
697 iput(inode);
698 inode = NULL;
699 }
700 }
701 if (!inode) {
702 /* For now, do nothing
703 * What we could do is:
704 * follow the file starting at fh[4], and record
705 * the ".." entry, and the name of the fh[2] entry.
706 * The follow the ".." file finding the next step up.
707 * This way we build a path to the root of
708 * the tree. If this works, we lookup the path and so
709 * get this inode into the cache.
710 * Finally try the fat_iget lookup again
711 * If that fails, then weare totally out of luck
712 * But all that is for another day
713 */
714 }
715 if (!inode)
716 return ERR_PTR(-ESTALE);
717
718
719 /* now to find a dentry.
720 * If possible, get a well-connected one
721 */
722 result = d_alloc_anon(inode);
723 if (result == NULL) {
724 iput(inode);
725 return ERR_PTR(-ENOMEM);
726 }
727 result->d_op = sb->s_root->d_op;
728 return result;
729 }
730
731 static int
732 fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable)
733 {
734 int len = *lenp;
735 struct inode *inode = de->d_inode;
736 u32 ipos_h, ipos_m, ipos_l;
737
738 if (len < 5)
739 return 255; /* no room */
740
741 ipos_h = MSDOS_I(inode)->i_pos >> 8;
742 ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24;
743 ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28;
744 *lenp = 5;
745 fh[0] = inode->i_ino;
746 fh[1] = inode->i_generation;
747 fh[2] = ipos_h;
748 fh[3] = ipos_m | MSDOS_I(inode)->i_logstart;
749 spin_lock(&de->d_lock);
750 fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart;
751 spin_unlock(&de->d_lock);
752 return 3;
753 }
754
755 static struct dentry *fat_get_parent(struct dentry *child)
756 {
757 struct buffer_head *bh;
758 struct msdos_dir_entry *de;
759 loff_t i_pos;
760 struct dentry *parent;
761 struct inode *inode;
762 int err;
763
764 lock_kernel();
765
766 err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos);
767 if (err) {
768 parent = ERR_PTR(err);
769 goto out;
770 }
771 inode = fat_build_inode(child->d_sb, de, i_pos);
772 brelse(bh);
773 if (IS_ERR(inode)) {
774 parent = ERR_PTR(PTR_ERR(inode));
775 goto out;
776 }
777 parent = d_alloc_anon(inode);
778 if (!parent) {
779 iput(inode);
780 parent = ERR_PTR(-ENOMEM);
781 }
782 out:
783 unlock_kernel();
784
785 return parent;
786 }
787
788 static struct export_operations fat_export_ops = {
789 .decode_fh = fat_decode_fh,
790 .encode_fh = fat_encode_fh,
791 .get_dentry = fat_get_dentry,
792 .get_parent = fat_get_parent,
793 };
794
795 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt)
796 {
797 struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb);
798 struct fat_mount_options *opts = &sbi->options;
799 int isvfat = opts->isvfat;
800
801 if (opts->fs_uid != 0)
802 seq_printf(m, ",uid=%u", opts->fs_uid);
803 if (opts->fs_gid != 0)
804 seq_printf(m, ",gid=%u", opts->fs_gid);
805 seq_printf(m, ",fmask=%04o", opts->fs_fmask);
806 seq_printf(m, ",dmask=%04o", opts->fs_dmask);
807 if (sbi->nls_disk)
808 seq_printf(m, ",codepage=%s", sbi->nls_disk->charset);
809 if (isvfat) {
810 if (sbi->nls_io)
811 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
812
813 switch (opts->shortname) {
814 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
815 seq_puts(m, ",shortname=win95");
816 break;
817 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
818 seq_puts(m, ",shortname=winnt");
819 break;
820 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
821 seq_puts(m, ",shortname=mixed");
822 break;
823 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
824 /* seq_puts(m, ",shortname=lower"); */
825 break;
826 default:
827 seq_puts(m, ",shortname=unknown");
828 break;
829 }
830 }
831 if (opts->name_check != 'n')
832 seq_printf(m, ",check=%c", opts->name_check);
833 if (opts->quiet)
834 seq_puts(m, ",quiet");
835 if (opts->showexec)
836 seq_puts(m, ",showexec");
837 if (opts->sys_immutable)
838 seq_puts(m, ",sys_immutable");
839 if (!isvfat) {
840 if (opts->dotsOK)
841 seq_puts(m, ",dotsOK=yes");
842 if (opts->nocase)
843 seq_puts(m, ",nocase");
844 } else {
845 if (opts->utf8)
846 seq_puts(m, ",utf8");
847 if (opts->unicode_xlate)
848 seq_puts(m, ",uni_xlate");
849 if (!opts->numtail)
850 seq_puts(m, ",nonumtail");
851 }
852
853 return 0;
854 }
855
856 enum {
857 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
858 Opt_umask, Opt_dmask, Opt_fmask, Opt_codepage, Opt_nocase,
859 Opt_quiet, Opt_showexec, Opt_debug, Opt_immutable,
860 Opt_dots, Opt_nodots,
861 Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
862 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
863 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
864 Opt_obsolate, Opt_err,
865 };
866
867 static match_table_t fat_tokens = {
868 {Opt_check_r, "check=relaxed"},
869 {Opt_check_s, "check=strict"},
870 {Opt_check_n, "check=normal"},
871 {Opt_check_r, "check=r"},
872 {Opt_check_s, "check=s"},
873 {Opt_check_n, "check=n"},
874 {Opt_uid, "uid=%u"},
875 {Opt_gid, "gid=%u"},
876 {Opt_umask, "umask=%o"},
877 {Opt_dmask, "dmask=%o"},
878 {Opt_fmask, "fmask=%o"},
879 {Opt_codepage, "codepage=%u"},
880 {Opt_nocase, "nocase"},
881 {Opt_quiet, "quiet"},
882 {Opt_showexec, "showexec"},
883 {Opt_debug, "debug"},
884 {Opt_immutable, "sys_immutable"},
885 {Opt_obsolate, "conv=binary"},
886 {Opt_obsolate, "conv=text"},
887 {Opt_obsolate, "conv=auto"},
888 {Opt_obsolate, "conv=b"},
889 {Opt_obsolate, "conv=t"},
890 {Opt_obsolate, "conv=a"},
891 {Opt_obsolate, "fat=%u"},
892 {Opt_obsolate, "blocksize=%u"},
893 {Opt_obsolate, "cvf_format=%20s"},
894 {Opt_obsolate, "cvf_options=%100s"},
895 {Opt_obsolate, "posix"},
896 {Opt_err, NULL}
897 };
898 static match_table_t msdos_tokens = {
899 {Opt_nodots, "nodots"},
900 {Opt_nodots, "dotsOK=no"},
901 {Opt_dots, "dots"},
902 {Opt_dots, "dotsOK=yes"},
903 {Opt_err, NULL}
904 };
905 static match_table_t vfat_tokens = {
906 {Opt_charset, "iocharset=%s"},
907 {Opt_shortname_lower, "shortname=lower"},
908 {Opt_shortname_win95, "shortname=win95"},
909 {Opt_shortname_winnt, "shortname=winnt"},
910 {Opt_shortname_mixed, "shortname=mixed"},
911 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */
912 {Opt_utf8_no, "utf8=no"},
913 {Opt_utf8_no, "utf8=false"},
914 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */
915 {Opt_utf8_yes, "utf8=yes"},
916 {Opt_utf8_yes, "utf8=true"},
917 {Opt_utf8_yes, "utf8"},
918 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */
919 {Opt_uni_xl_no, "uni_xlate=no"},
920 {Opt_uni_xl_no, "uni_xlate=false"},
921 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */
922 {Opt_uni_xl_yes, "uni_xlate=yes"},
923 {Opt_uni_xl_yes, "uni_xlate=true"},
924 {Opt_uni_xl_yes, "uni_xlate"},
925 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */
926 {Opt_nonumtail_no, "nonumtail=no"},
927 {Opt_nonumtail_no, "nonumtail=false"},
928 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */
929 {Opt_nonumtail_yes, "nonumtail=yes"},
930 {Opt_nonumtail_yes, "nonumtail=true"},
931 {Opt_nonumtail_yes, "nonumtail"},
932 {Opt_err, NULL}
933 };
934
935 static int parse_options(char *options, int is_vfat, int silent, int *debug,
936 struct fat_mount_options *opts)
937 {
938 char *p;
939 substring_t args[MAX_OPT_ARGS];
940 int option;
941 char *iocharset;
942
943 opts->isvfat = is_vfat;
944
945 opts->fs_uid = current->uid;
946 opts->fs_gid = current->gid;
947 opts->fs_fmask = opts->fs_dmask = current->fs->umask;
948 opts->codepage = fat_default_codepage;
949 opts->iocharset = fat_default_iocharset;
950 if (is_vfat)
951 opts->shortname = VFAT_SFN_DISPLAY_LOWER|VFAT_SFN_CREATE_WIN95;
952 else
953 opts->shortname = 0;
954 opts->name_check = 'n';
955 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0;
956 opts->utf8 = opts->unicode_xlate = 0;
957 opts->numtail = 1;
958 opts->nocase = 0;
959 *debug = 0;
960
961 if (!options)
962 return 0;
963
964 while ((p = strsep(&options, ",")) != NULL) {
965 int token;
966 if (!*p)
967 continue;
968
969 token = match_token(p, fat_tokens, args);
970 if (token == Opt_err) {
971 if (is_vfat)
972 token = match_token(p, vfat_tokens, args);
973 else
974 token = match_token(p, msdos_tokens, args);
975 }
976 switch (token) {
977 case Opt_check_s:
978 opts->name_check = 's';
979 break;
980 case Opt_check_r:
981 opts->name_check = 'r';
982 break;
983 case Opt_check_n:
984 opts->name_check = 'n';
985 break;
986 case Opt_nocase:
987 if (!is_vfat)
988 opts->nocase = 1;
989 else {
990 /* for backward compatibility */
991 opts->shortname = VFAT_SFN_DISPLAY_WIN95
992 | VFAT_SFN_CREATE_WIN95;
993 }
994 break;
995 case Opt_quiet:
996 opts->quiet = 1;
997 break;
998 case Opt_showexec:
999 opts->showexec = 1;
1000 break;
1001 case Opt_debug:
1002 *debug = 1;
1003 break;
1004 case Opt_immutable:
1005 opts->sys_immutable = 1;
1006 break;
1007 case Opt_uid:
1008 if (match_int(&args[0], &option))
1009 return 0;
1010 opts->fs_uid = option;
1011 break;
1012 case Opt_gid:
1013 if (match_int(&args[0], &option))
1014 return 0;
1015 opts->fs_gid = option;
1016 break;
1017 case Opt_umask:
1018 if (match_octal(&args[0], &option))
1019 return 0;
1020 opts->fs_fmask = opts->fs_dmask = option;
1021 break;
1022 case Opt_dmask:
1023 if (match_octal(&args[0], &option))
1024 return 0;
1025 opts->fs_dmask = option;
1026 break;
1027 case Opt_fmask:
1028 if (match_octal(&args[0], &option))
1029 return 0;
1030 opts->fs_fmask = option;
1031 break;
1032 case Opt_codepage:
1033 if (match_int(&args[0], &option))
1034 return 0;
1035 opts->codepage = option;
1036 break;
1037
1038 /* msdos specific */
1039 case Opt_dots:
1040 opts->dotsOK = 1;
1041 break;
1042 case Opt_nodots:
1043 opts->dotsOK = 0;
1044 break;
1045
1046 /* vfat specific */
1047 case Opt_charset:
1048 if (opts->iocharset != fat_default_iocharset)
1049 kfree(opts->iocharset);
1050 iocharset = match_strdup(&args[0]);
1051 if (!iocharset)
1052 return -ENOMEM;
1053 opts->iocharset = iocharset;
1054 break;
1055 case Opt_shortname_lower:
1056 opts->shortname = VFAT_SFN_DISPLAY_LOWER
1057 | VFAT_SFN_CREATE_WIN95;
1058 break;
1059 case Opt_shortname_win95:
1060 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1061 | VFAT_SFN_CREATE_WIN95;
1062 break;
1063 case Opt_shortname_winnt:
1064 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1065 | VFAT_SFN_CREATE_WINNT;
1066 break;
1067 case Opt_shortname_mixed:
1068 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1069 | VFAT_SFN_CREATE_WIN95;
1070 break;
1071 case Opt_utf8_no: /* 0 or no or false */
1072 opts->utf8 = 0;
1073 break;
1074 case Opt_utf8_yes: /* empty or 1 or yes or true */
1075 opts->utf8 = 1;
1076 break;
1077 case Opt_uni_xl_no: /* 0 or no or false */
1078 opts->unicode_xlate = 0;
1079 break;
1080 case Opt_uni_xl_yes: /* empty or 1 or yes or true */
1081 opts->unicode_xlate = 1;
1082 break;
1083 case Opt_nonumtail_no: /* 0 or no or false */
1084 opts->numtail = 1; /* negated option */
1085 break;
1086 case Opt_nonumtail_yes: /* empty or 1 or yes or true */
1087 opts->numtail = 0; /* negated option */
1088 break;
1089
1090 /* obsolete mount options */
1091 case Opt_obsolate:
1092 printk(KERN_INFO "FAT: \"%s\" option is obsolete, "
1093 "not supported now\n", p);
1094 break;
1095 /* unknown option */
1096 default:
1097 if (!silent) {
1098 printk(KERN_ERR
1099 "FAT: Unrecognized mount option \"%s\" "
1100 "or missing value\n", p);
1101 }
1102 return -EINVAL;
1103 }
1104 }
1105 /* UTF-8 doesn't provide FAT semantics */
1106 if (!strcmp(opts->iocharset, "utf8")) {
1107 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset"
1108 " for FAT filesystems, filesystem will be case sensitive!\n");
1109 }
1110
1111 if (opts->unicode_xlate)
1112 opts->utf8 = 0;
1113
1114 return 0;
1115 }
1116
1117 static int fat_read_root(struct inode *inode)
1118 {
1119 struct super_block *sb = inode->i_sb;
1120 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1121 int error;
1122
1123 MSDOS_I(inode)->i_pos = 0;
1124 inode->i_uid = sbi->options.fs_uid;
1125 inode->i_gid = sbi->options.fs_gid;
1126 inode->i_version++;
1127 inode->i_generation = 0;
1128 inode->i_mode = (S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR;
1129 inode->i_op = sbi->dir_ops;
1130 inode->i_fop = &fat_dir_operations;
1131 if (sbi->fat_bits == 32) {
1132 MSDOS_I(inode)->i_start = sbi->root_cluster;
1133 error = fat_calc_dir_size(inode);
1134 if (error < 0)
1135 return error;
1136 } else {
1137 MSDOS_I(inode)->i_start = 0;
1138 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1139 }
1140 inode->i_blksize = sbi->cluster_size;
1141 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1142 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1143 MSDOS_I(inode)->i_logstart = 0;
1144 MSDOS_I(inode)->mmu_private = inode->i_size;
1145
1146 MSDOS_I(inode)->i_attrs = ATTR_NONE;
1147 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1148 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1149 inode->i_nlink = fat_subdirs(inode)+2;
1150
1151 return 0;
1152 }
1153
1154 /*
1155 * Read the super block of an MS-DOS FS.
1156 */
1157 int fat_fill_super(struct super_block *sb, void *data, int silent,
1158 struct inode_operations *fs_dir_inode_ops, int isvfat)
1159 {
1160 struct inode *root_inode = NULL;
1161 struct buffer_head *bh;
1162 struct fat_boot_sector *b;
1163 struct msdos_sb_info *sbi;
1164 u16 logical_sector_size;
1165 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1166 int debug;
1167 unsigned int media;
1168 long error;
1169 char buf[50];
1170
1171 sbi = kmalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1172 if (!sbi)
1173 return -ENOMEM;
1174 sb->s_fs_info = sbi;
1175 memset(sbi, 0, sizeof(struct msdos_sb_info));
1176
1177 sb->s_flags |= MS_NODIRATIME;
1178 sb->s_magic = MSDOS_SUPER_MAGIC;
1179 sb->s_op = &fat_sops;
1180 sb->s_export_op = &fat_export_ops;
1181 sbi->dir_ops = fs_dir_inode_ops;
1182
1183 error = parse_options(data, isvfat, silent, &debug, &sbi->options);
1184 if (error)
1185 goto out_fail;
1186
1187 error = -EIO;
1188 sb_min_blocksize(sb, 512);
1189 bh = sb_bread(sb, 0);
1190 if (bh == NULL) {
1191 printk(KERN_ERR "FAT: unable to read boot sector\n");
1192 goto out_fail;
1193 }
1194
1195 b = (struct fat_boot_sector *) bh->b_data;
1196 if (!b->reserved) {
1197 if (!silent)
1198 printk(KERN_ERR "FAT: bogus number of reserved sectors\n");
1199 brelse(bh);
1200 goto out_invalid;
1201 }
1202 if (!b->fats) {
1203 if (!silent)
1204 printk(KERN_ERR "FAT: bogus number of FAT structure\n");
1205 brelse(bh);
1206 goto out_invalid;
1207 }
1208
1209 /*
1210 * Earlier we checked here that b->secs_track and b->head are nonzero,
1211 * but it turns out valid FAT filesystems can have zero there.
1212 */
1213
1214 media = b->media;
1215 if (!FAT_VALID_MEDIA(media)) {
1216 if (!silent)
1217 printk(KERN_ERR "FAT: invalid media value (0x%02x)\n",
1218 media);
1219 brelse(bh);
1220 goto out_invalid;
1221 }
1222 logical_sector_size =
1223 le16_to_cpu(get_unaligned((__le16 *)&b->sector_size));
1224 if (!logical_sector_size
1225 || (logical_sector_size & (logical_sector_size - 1))
1226 || (logical_sector_size < 512)
1227 || (PAGE_CACHE_SIZE < logical_sector_size)) {
1228 if (!silent)
1229 printk(KERN_ERR "FAT: bogus logical sector size %u\n",
1230 logical_sector_size);
1231 brelse(bh);
1232 goto out_invalid;
1233 }
1234 sbi->sec_per_clus = b->sec_per_clus;
1235 if (!sbi->sec_per_clus
1236 || (sbi->sec_per_clus & (sbi->sec_per_clus - 1))) {
1237 if (!silent)
1238 printk(KERN_ERR "FAT: bogus sectors per cluster %u\n",
1239 sbi->sec_per_clus);
1240 brelse(bh);
1241 goto out_invalid;
1242 }
1243
1244 if (logical_sector_size < sb->s_blocksize) {
1245 printk(KERN_ERR "FAT: logical sector size too small for device"
1246 " (logical sector size = %u)\n", logical_sector_size);
1247 brelse(bh);
1248 goto out_fail;
1249 }
1250 if (logical_sector_size > sb->s_blocksize) {
1251 brelse(bh);
1252
1253 if (!sb_set_blocksize(sb, logical_sector_size)) {
1254 printk(KERN_ERR "FAT: unable to set blocksize %u\n",
1255 logical_sector_size);
1256 goto out_fail;
1257 }
1258 bh = sb_bread(sb, 0);
1259 if (bh == NULL) {
1260 printk(KERN_ERR "FAT: unable to read boot sector"
1261 " (logical sector size = %lu)\n",
1262 sb->s_blocksize);
1263 goto out_fail;
1264 }
1265 b = (struct fat_boot_sector *) bh->b_data;
1266 }
1267
1268 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1269 sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1270 sbi->fats = b->fats;
1271 sbi->fat_bits = 0; /* Don't know yet */
1272 sbi->fat_start = le16_to_cpu(b->reserved);
1273 sbi->fat_length = le16_to_cpu(b->fat_length);
1274 sbi->root_cluster = 0;
1275 sbi->free_clusters = -1; /* Don't know yet */
1276 sbi->prev_free = FAT_START_ENT;
1277
1278 if (!sbi->fat_length && b->fat32_length) {
1279 struct fat_boot_fsinfo *fsinfo;
1280 struct buffer_head *fsinfo_bh;
1281
1282 /* Must be FAT32 */
1283 sbi->fat_bits = 32;
1284 sbi->fat_length = le32_to_cpu(b->fat32_length);
1285 sbi->root_cluster = le32_to_cpu(b->root_cluster);
1286
1287 sb->s_maxbytes = 0xffffffff;
1288
1289 /* MC - if info_sector is 0, don't multiply by 0 */
1290 sbi->fsinfo_sector = le16_to_cpu(b->info_sector);
1291 if (sbi->fsinfo_sector == 0)
1292 sbi->fsinfo_sector = 1;
1293
1294 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1295 if (fsinfo_bh == NULL) {
1296 printk(KERN_ERR "FAT: bread failed, FSINFO block"
1297 " (sector = %lu)\n", sbi->fsinfo_sector);
1298 brelse(bh);
1299 goto out_fail;
1300 }
1301
1302 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1303 if (!IS_FSINFO(fsinfo)) {
1304 printk(KERN_WARNING
1305 "FAT: Did not find valid FSINFO signature.\n"
1306 " Found signature1 0x%08x signature2 0x%08x"
1307 " (sector = %lu)\n",
1308 le32_to_cpu(fsinfo->signature1),
1309 le32_to_cpu(fsinfo->signature2),
1310 sbi->fsinfo_sector);
1311 } else {
1312 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1313 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1314 }
1315
1316 brelse(fsinfo_bh);
1317 }
1318
1319 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1320 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1321
1322 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1323 sbi->dir_entries =
1324 le16_to_cpu(get_unaligned((__le16 *)&b->dir_entries));
1325 if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1326 if (!silent)
1327 printk(KERN_ERR "FAT: bogus directroy-entries per block"
1328 " (%u)\n", sbi->dir_entries);
1329 brelse(bh);
1330 goto out_invalid;
1331 }
1332
1333 rootdir_sectors = sbi->dir_entries
1334 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1335 sbi->data_start = sbi->dir_start + rootdir_sectors;
1336 total_sectors = le16_to_cpu(get_unaligned((__le16 *)&b->sectors));
1337 if (total_sectors == 0)
1338 total_sectors = le32_to_cpu(b->total_sect);
1339
1340 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1341
1342 if (sbi->fat_bits != 32)
1343 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1344
1345 /* check that FAT table does not overflow */
1346 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1347 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1348 if (total_clusters > MAX_FAT(sb)) {
1349 if (!silent)
1350 printk(KERN_ERR "FAT: count of clusters too big (%u)\n",
1351 total_clusters);
1352 brelse(bh);
1353 goto out_invalid;
1354 }
1355
1356 sbi->max_cluster = total_clusters + FAT_START_ENT;
1357 /* check the free_clusters, it's not necessarily correct */
1358 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1359 sbi->free_clusters = -1;
1360 /* check the prev_free, it's not necessarily correct */
1361 sbi->prev_free %= sbi->max_cluster;
1362 if (sbi->prev_free < FAT_START_ENT)
1363 sbi->prev_free = FAT_START_ENT;
1364
1365 brelse(bh);
1366
1367 /* set up enough so that it can read an inode */
1368 fat_hash_init(sb);
1369 fat_ent_access_init(sb);
1370
1371 /*
1372 * The low byte of FAT's first entry must have same value with
1373 * media-field. But in real world, too many devices is
1374 * writing wrong value. So, removed that validity check.
1375 *
1376 * if (FAT_FIRST_ENT(sb, media) != first)
1377 */
1378
1379 error = -EINVAL;
1380 sprintf(buf, "cp%d", sbi->options.codepage);
1381 sbi->nls_disk = load_nls(buf);
1382 if (!sbi->nls_disk) {
1383 printk(KERN_ERR "FAT: codepage %s not found\n", buf);
1384 goto out_fail;
1385 }
1386
1387 /* FIXME: utf8 is using iocharset for upper/lower conversion */
1388 if (sbi->options.isvfat) {
1389 sbi->nls_io = load_nls(sbi->options.iocharset);
1390 if (!sbi->nls_io) {
1391 printk(KERN_ERR "FAT: IO charset %s not found\n",
1392 sbi->options.iocharset);
1393 goto out_fail;
1394 }
1395 }
1396
1397 error = -ENOMEM;
1398 root_inode = new_inode(sb);
1399 if (!root_inode)
1400 goto out_fail;
1401 root_inode->i_ino = MSDOS_ROOT_INO;
1402 root_inode->i_version = 1;
1403 error = fat_read_root(root_inode);
1404 if (error < 0)
1405 goto out_fail;
1406 error = -ENOMEM;
1407 insert_inode_hash(root_inode);
1408 sb->s_root = d_alloc_root(root_inode);
1409 if (!sb->s_root) {
1410 printk(KERN_ERR "FAT: get root inode failed\n");
1411 goto out_fail;
1412 }
1413
1414 return 0;
1415
1416 out_invalid:
1417 error = -EINVAL;
1418 if (!silent)
1419 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem"
1420 " on dev %s.\n", sb->s_id);
1421
1422 out_fail:
1423 if (root_inode)
1424 iput(root_inode);
1425 if (sbi->nls_io)
1426 unload_nls(sbi->nls_io);
1427 if (sbi->nls_disk)
1428 unload_nls(sbi->nls_disk);
1429 if (sbi->options.iocharset != fat_default_iocharset)
1430 kfree(sbi->options.iocharset);
1431 sb->s_fs_info = NULL;
1432 kfree(sbi);
1433 return error;
1434 }
1435
1436 EXPORT_SYMBOL_GPL(fat_fill_super);
1437
1438 static int __init init_fat_fs(void)
1439 {
1440 int err;
1441
1442 err = fat_cache_init();
1443 if (err)
1444 return err;
1445
1446 err = fat_init_inodecache();
1447 if (err)
1448 goto failed;
1449
1450 return 0;
1451
1452 failed:
1453 fat_cache_destroy();
1454 return err;
1455 }
1456
1457 static void __exit exit_fat_fs(void)
1458 {
1459 fat_cache_destroy();
1460 fat_destroy_inodecache();
1461 }
1462
1463 module_init(init_fat_fs)
1464 module_exit(exit_fat_fs)
1465
1466 MODULE_LICENSE("GPL");
linux-next