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