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Initial commit
[wrt350n-kernel.git] / fs / fat / inode.c
blob53f3cf62b7c18c945bdcc3caaddf9466a91ca391
1 /*
2 * linux/fs/fat/inode.c
3 *
4 * Written 1992,1993 by Werner Almesberger
5 * VFAT extensions by Gordon Chaffee, merged with msdos fs by Henrik Storner
6 * Rewritten for the constant inumbers support by Al Viro
7 *
8 * Fixes:
9 *
10 * Max Cohan: Fixed invalid FSINFO offset when info_sector is 0
11 */
12
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/time.h>
16 #include <linux/slab.h>
17 #include <linux/smp_lock.h>
18 #include <linux/seq_file.h>
19 #include <linux/msdos_fs.h>
20 #include <linux/pagemap.h>
21 #include <linux/mpage.h>
22 #include <linux/buffer_head.h>
23 #include <linux/exportfs.h>
24 #include <linux/mount.h>
25 #include <linux/vfs.h>
26 #include <linux/parser.h>
27 #include <linux/uio.h>
28 #include <linux/writeback.h>
29 #include <linux/log2.h>
30 #include <asm/unaligned.h>
31
32 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET
33 /* if user don't select VFAT, this is undefined. */
34 #define CONFIG_FAT_DEFAULT_IOCHARSET ""
35 #endif
36
37 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
38 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
39
40
41 static int fat_add_cluster(struct inode *inode)
42 {
43 int err, cluster;
44
45 err = fat_alloc_clusters(inode, &cluster, 1);
46 if (err)
47 return err;
48 /* FIXME: this cluster should be added after data of this
49 * cluster is writed */
50 err = fat_chain_add(inode, cluster, 1);
51 if (err)
52 fat_free_clusters(inode, cluster);
53 return err;
54 }
55
56 static inline int __fat_get_block(struct inode *inode, sector_t iblock,
57 unsigned long *max_blocks,
58 struct buffer_head *bh_result, int create)
59 {
60 struct super_block *sb = inode->i_sb;
61 struct msdos_sb_info *sbi = MSDOS_SB(sb);
62 unsigned long mapped_blocks;
63 sector_t phys;
64 int err, offset;
65
66 err = fat_bmap(inode, iblock, &phys, &mapped_blocks);
67 if (err)
68 return err;
69 if (phys) {
70 map_bh(bh_result, sb, phys);
71 *max_blocks = min(mapped_blocks, *max_blocks);
72 return 0;
73 }
74 if (!create)
75 return 0;
76
77 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
78 fat_fs_panic(sb, "corrupted file size (i_pos %lld, %lld)",
79 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
80 return -EIO;
81 }
82
83 offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
84 if (!offset) {
85 /* TODO: multiple cluster allocation would be desirable. */
86 err = fat_add_cluster(inode);
87 if (err)
88 return err;
89 }
90 /* available blocks on this cluster */
91 mapped_blocks = sbi->sec_per_clus - offset;
92
93 *max_blocks = min(mapped_blocks, *max_blocks);
94 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
95
96 err = fat_bmap(inode, iblock, &phys, &mapped_blocks);
97 if (err)
98 return err;
99
100 BUG_ON(!phys);
101 BUG_ON(*max_blocks != mapped_blocks);
102 set_buffer_new(bh_result);
103 map_bh(bh_result, sb, phys);
104
105 return 0;
106 }
107
108 static int fat_get_block(struct inode *inode, sector_t iblock,
109 struct buffer_head *bh_result, int create)
110 {
111 struct super_block *sb = inode->i_sb;
112 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
113 int err;
114
115 err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create);
116 if (err)
117 return err;
118 bh_result->b_size = max_blocks << sb->s_blocksize_bits;
119 return 0;
120 }
121
122 static int fat_writepage(struct page *page, struct writeback_control *wbc)
123 {
124 return block_write_full_page(page, fat_get_block, wbc);
125 }
126
127 static int fat_writepages(struct address_space *mapping,
128 struct writeback_control *wbc)
129 {
130 return mpage_writepages(mapping, wbc, fat_get_block);
131 }
132
133 static int fat_readpage(struct file *file, struct page *page)
134 {
135 return mpage_readpage(page, fat_get_block);
136 }
137
138 static int fat_readpages(struct file *file, struct address_space *mapping,
139 struct list_head *pages, unsigned nr_pages)
140 {
141 return mpage_readpages(mapping, pages, nr_pages, fat_get_block);
142 }
143
144 static int fat_write_begin(struct file *file, struct address_space *mapping,
145 loff_t pos, unsigned len, unsigned flags,
146 struct page **pagep, void **fsdata)
147 {
148 *pagep = NULL;
149 return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
150 fat_get_block,
151 &MSDOS_I(mapping->host)->mmu_private);
152 }
153
154 static int fat_write_end(struct file *file, struct address_space *mapping,
155 loff_t pos, unsigned len, unsigned copied,
156 struct page *pagep, void *fsdata)
157 {
158 struct inode *inode = mapping->host;
159 int err;
160 err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
161 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
162 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
163 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
164 mark_inode_dirty(inode);
165 }
166 return err;
167 }
168
169 static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
170 const struct iovec *iov,
171 loff_t offset, unsigned long nr_segs)
172 {
173 struct file *file = iocb->ki_filp;
174 struct inode *inode = file->f_mapping->host;
175
176 if (rw == WRITE) {
177 /*
178 * FIXME: blockdev_direct_IO() doesn't use ->prepare_write(),
179 * so we need to update the ->mmu_private to block boundary.
180 *
181 * But we must fill the remaining area or hole by nul for
182 * updating ->mmu_private.
183 *
184 * Return 0, and fallback to normal buffered write.
185 */
186 loff_t size = offset + iov_length(iov, nr_segs);
187 if (MSDOS_I(inode)->mmu_private < size)
188 return 0;
189 }
190
191 /*
192 * FAT need to use the DIO_LOCKING for avoiding the race
193 * condition of fat_get_block() and ->truncate().
194 */
195 return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
196 offset, nr_segs, fat_get_block, NULL);
197 }
198
199 static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
200 {
201 return generic_block_bmap(mapping, block, fat_get_block);
202 }
203
204 static const struct address_space_operations fat_aops = {
205 .readpage = fat_readpage,
206 .readpages = fat_readpages,
207 .writepage = fat_writepage,
208 .writepages = fat_writepages,
209 .sync_page = block_sync_page,
210 .write_begin = fat_write_begin,
211 .write_end = fat_write_end,
212 .direct_IO = fat_direct_IO,
213 .bmap = _fat_bmap
214 };
215
216 /*
217 * New FAT inode stuff. We do the following:
218 * a) i_ino is constant and has nothing with on-disk location.
219 * b) FAT manages its own cache of directory entries.
220 * c) *This* cache is indexed by on-disk location.
221 * d) inode has an associated directory entry, all right, but
222 * it may be unhashed.
223 * e) currently entries are stored within struct inode. That should
224 * change.
225 * f) we deal with races in the following way:
226 * 1. readdir() and lookup() do FAT-dir-cache lookup.
227 * 2. rename() unhashes the F-d-c entry and rehashes it in
228 * a new place.
229 * 3. unlink() and rmdir() unhash F-d-c entry.
230 * 4. fat_write_inode() checks whether the thing is unhashed.
231 * If it is we silently return. If it isn't we do bread(),
232 * check if the location is still valid and retry if it
233 * isn't. Otherwise we do changes.
234 * 5. Spinlock is used to protect hash/unhash/location check/lookup
235 * 6. fat_clear_inode() unhashes the F-d-c entry.
236 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry
237 * and consider negative result as cache miss.
238 */
239
240 static void fat_hash_init(struct super_block *sb)
241 {
242 struct msdos_sb_info *sbi = MSDOS_SB(sb);
243 int i;
244
245 spin_lock_init(&sbi->inode_hash_lock);
246 for (i = 0; i < FAT_HASH_SIZE; i++)
247 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
248 }
249
250 static inline unsigned long fat_hash(struct super_block *sb, loff_t i_pos)
251 {
252 unsigned long tmp = (unsigned long)i_pos | (unsigned long) sb;
253 tmp = tmp + (tmp >> FAT_HASH_BITS) + (tmp >> FAT_HASH_BITS * 2);
254 return tmp & FAT_HASH_MASK;
255 }
256
257 void fat_attach(struct inode *inode, loff_t i_pos)
258 {
259 struct super_block *sb = inode->i_sb;
260 struct msdos_sb_info *sbi = MSDOS_SB(sb);
261
262 spin_lock(&sbi->inode_hash_lock);
263 MSDOS_I(inode)->i_pos = i_pos;
264 hlist_add_head(&MSDOS_I(inode)->i_fat_hash,
265 sbi->inode_hashtable + fat_hash(sb, i_pos));
266 spin_unlock(&sbi->inode_hash_lock);
267 }
268
269 EXPORT_SYMBOL_GPL(fat_attach);
270
271 void fat_detach(struct inode *inode)
272 {
273 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
274 spin_lock(&sbi->inode_hash_lock);
275 MSDOS_I(inode)->i_pos = 0;
276 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
277 spin_unlock(&sbi->inode_hash_lock);
278 }
279
280 EXPORT_SYMBOL_GPL(fat_detach);
281
282 struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
283 {
284 struct msdos_sb_info *sbi = MSDOS_SB(sb);
285 struct hlist_head *head = sbi->inode_hashtable + fat_hash(sb, i_pos);
286 struct hlist_node *_p;
287 struct msdos_inode_info *i;
288 struct inode *inode = NULL;
289
290 spin_lock(&sbi->inode_hash_lock);
291 hlist_for_each_entry(i, _p, head, i_fat_hash) {
292 BUG_ON(i->vfs_inode.i_sb != sb);
293 if (i->i_pos != i_pos)
294 continue;
295 inode = igrab(&i->vfs_inode);
296 if (inode)
297 break;
298 }
299 spin_unlock(&sbi->inode_hash_lock);
300 return inode;
301 }
302
303 static int is_exec(unsigned char *extension)
304 {
305 unsigned char *exe_extensions = "EXECOMBAT", *walk;
306
307 for (walk = exe_extensions; *walk; walk += 3)
308 if (!strncmp(extension, walk, 3))
309 return 1;
310 return 0;
311 }
312
313 static int fat_calc_dir_size(struct inode *inode)
314 {
315 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
316 int ret, fclus, dclus;
317
318 inode->i_size = 0;
319 if (MSDOS_I(inode)->i_start == 0)
320 return 0;
321
322 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
323 if (ret < 0)
324 return ret;
325 inode->i_size = (fclus + 1) << sbi->cluster_bits;
326
327 return 0;
328 }
329
330 /* doesn't deal with root inode */
331 static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
332 {
333 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
334 int error;
335
336 MSDOS_I(inode)->i_pos = 0;
337 inode->i_uid = sbi->options.fs_uid;
338 inode->i_gid = sbi->options.fs_gid;
339 inode->i_version++;
340 inode->i_generation = get_seconds();
341
342 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
343 inode->i_generation &= ~1;
344 inode->i_mode = MSDOS_MKMODE(de->attr,
345 S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR;
346 inode->i_op = sbi->dir_ops;
347 inode->i_fop = &fat_dir_operations;
348
349 MSDOS_I(inode)->i_start = le16_to_cpu(de->start);
350 if (sbi->fat_bits == 32)
351 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16);
352
353 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
354 error = fat_calc_dir_size(inode);
355 if (error < 0)
356 return error;
357 MSDOS_I(inode)->mmu_private = inode->i_size;
358
359 inode->i_nlink = fat_subdirs(inode);
360 } else { /* not a directory */
361 inode->i_generation |= 1;
362 inode->i_mode = MSDOS_MKMODE(de->attr,
363 ((sbi->options.showexec && !is_exec(de->name + 8))
364 ? S_IRUGO|S_IWUGO : S_IRWXUGO)
365 & ~sbi->options.fs_fmask) | S_IFREG;
366 MSDOS_I(inode)->i_start = le16_to_cpu(de->start);
367 if (sbi->fat_bits == 32)
368 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16);
369
370 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
371 inode->i_size = le32_to_cpu(de->size);
372 inode->i_op = &fat_file_inode_operations;
373 inode->i_fop = &fat_file_operations;
374 inode->i_mapping->a_ops = &fat_aops;
375 MSDOS_I(inode)->mmu_private = inode->i_size;
376 }
377 if (de->attr & ATTR_SYS) {
378 if (sbi->options.sys_immutable)
379 inode->i_flags |= S_IMMUTABLE;
380 }
381 MSDOS_I(inode)->i_attrs = de->attr & ATTR_UNUSED;
382 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
383 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
384 inode->i_mtime.tv_sec =
385 date_dos2unix(le16_to_cpu(de->time), le16_to_cpu(de->date));
386 inode->i_mtime.tv_nsec = 0;
387 if (sbi->options.isvfat) {
388 int secs = de->ctime_cs / 100;
389 int csecs = de->ctime_cs % 100;
390 inode->i_ctime.tv_sec =
391 date_dos2unix(le16_to_cpu(de->ctime),
392 le16_to_cpu(de->cdate)) + secs;
393 inode->i_ctime.tv_nsec = csecs * 10000000;
394 inode->i_atime.tv_sec =
395 date_dos2unix(0, le16_to_cpu(de->adate));
396 inode->i_atime.tv_nsec = 0;
397 } else
398 inode->i_ctime = inode->i_atime = inode->i_mtime;
399
400 return 0;
401 }
402
403 struct inode *fat_build_inode(struct super_block *sb,
404 struct msdos_dir_entry *de, loff_t i_pos)
405 {
406 struct inode *inode;
407 int err;
408
409 inode = fat_iget(sb, i_pos);
410 if (inode)
411 goto out;
412 inode = new_inode(sb);
413 if (!inode) {
414 inode = ERR_PTR(-ENOMEM);
415 goto out;
416 }
417 inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
418 inode->i_version = 1;
419 err = fat_fill_inode(inode, de);
420 if (err) {
421 iput(inode);
422 inode = ERR_PTR(err);
423 goto out;
424 }
425 fat_attach(inode, i_pos);
426 insert_inode_hash(inode);
427 out:
428 return inode;
429 }
430
431 EXPORT_SYMBOL_GPL(fat_build_inode);
432
433 static void fat_delete_inode(struct inode *inode)
434 {
435 truncate_inode_pages(&inode->i_data, 0);
436
437 if (!is_bad_inode(inode)) {
438 inode->i_size = 0;
439 fat_truncate(inode);
440 }
441 clear_inode(inode);
442 }
443
444 static void fat_clear_inode(struct inode *inode)
445 {
446 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
447
448 if (is_bad_inode(inode))
449 return;
450 lock_kernel();
451 spin_lock(&sbi->inode_hash_lock);
452 fat_cache_inval_inode(inode);
453 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
454 spin_unlock(&sbi->inode_hash_lock);
455 unlock_kernel();
456 }
457
458 static void fat_write_super(struct super_block *sb)
459 {
460 sb->s_dirt = 0;
461
462 if (!(sb->s_flags & MS_RDONLY))
463 fat_clusters_flush(sb);
464 }
465
466 static void fat_put_super(struct super_block *sb)
467 {
468 struct msdos_sb_info *sbi = MSDOS_SB(sb);
469
470 if (sbi->nls_disk) {
471 unload_nls(sbi->nls_disk);
472 sbi->nls_disk = NULL;
473 sbi->options.codepage = fat_default_codepage;
474 }
475 if (sbi->nls_io) {
476 unload_nls(sbi->nls_io);
477 sbi->nls_io = NULL;
478 }
479 if (sbi->options.iocharset != fat_default_iocharset) {
480 kfree(sbi->options.iocharset);
481 sbi->options.iocharset = fat_default_iocharset;
482 }
483
484 sb->s_fs_info = NULL;
485 kfree(sbi);
486 }
487
488 static struct kmem_cache *fat_inode_cachep;
489
490 static struct inode *fat_alloc_inode(struct super_block *sb)
491 {
492 struct msdos_inode_info *ei;
493 ei = kmem_cache_alloc(fat_inode_cachep, GFP_KERNEL);
494 if (!ei)
495 return NULL;
496 return &ei->vfs_inode;
497 }
498
499 static void fat_destroy_inode(struct inode *inode)
500 {
501 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
502 }
503
504 static void init_once(struct kmem_cache *cachep, void *foo)
505 {
506 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
507
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 static int __init fat_init_inodecache(void)
517 {
518 fat_inode_cachep = kmem_cache_create("fat_inode_cache",
519 sizeof(struct msdos_inode_info),
520 0, (SLAB_RECLAIM_ACCOUNT|
521 SLAB_MEM_SPREAD),
522 init_once);
523 if (fat_inode_cachep == NULL)
524 return -ENOMEM;
525 return 0;
526 }
527
528 static void __exit fat_destroy_inodecache(void)
529 {
530 kmem_cache_destroy(fat_inode_cachep);
531 }
532
533 static int fat_remount(struct super_block *sb, int *flags, char *data)
534 {
535 struct msdos_sb_info *sbi = MSDOS_SB(sb);
536 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME);
537 return 0;
538 }
539
540 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
541 {
542 struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
543
544 /* If the count of free cluster is still unknown, counts it here. */
545 if (sbi->free_clusters == -1) {
546 int err = fat_count_free_clusters(dentry->d_sb);
547 if (err)
548 return err;
549 }
550
551 buf->f_type = dentry->d_sb->s_magic;
552 buf->f_bsize = sbi->cluster_size;
553 buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
554 buf->f_bfree = sbi->free_clusters;
555 buf->f_bavail = sbi->free_clusters;
556 buf->f_namelen = sbi->options.isvfat ? 260 : 12;
557
558 return 0;
559 }
560
561 static int fat_write_inode(struct inode *inode, int wait)
562 {
563 struct super_block *sb = inode->i_sb;
564 struct msdos_sb_info *sbi = MSDOS_SB(sb);
565 struct buffer_head *bh;
566 struct msdos_dir_entry *raw_entry;
567 loff_t i_pos;
568 int err = 0;
569
570 retry:
571 i_pos = MSDOS_I(inode)->i_pos;
572 if (inode->i_ino == MSDOS_ROOT_INO || !i_pos)
573 return 0;
574
575 lock_kernel();
576 bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits);
577 if (!bh) {
578 printk(KERN_ERR "FAT: unable to read inode block "
579 "for updating (i_pos %lld)\n", i_pos);
580 err = -EIO;
581 goto out;
582 }
583 spin_lock(&sbi->inode_hash_lock);
584 if (i_pos != MSDOS_I(inode)->i_pos) {
585 spin_unlock(&sbi->inode_hash_lock);
586 brelse(bh);
587 unlock_kernel();
588 goto retry;
589 }
590
591 raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
592 [i_pos & (sbi->dir_per_block - 1)];
593 if (S_ISDIR(inode->i_mode))
594 raw_entry->size = 0;
595 else
596 raw_entry->size = cpu_to_le32(inode->i_size);
597 raw_entry->attr = fat_attr(inode);
598 raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart);
599 raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16);
600 fat_date_unix2dos(inode->i_mtime.tv_sec, &raw_entry->time, &raw_entry->date);
601 if (sbi->options.isvfat) {
602 __le16 atime;
603 fat_date_unix2dos(inode->i_ctime.tv_sec,&raw_entry->ctime,&raw_entry->cdate);
604 fat_date_unix2dos(inode->i_atime.tv_sec,&atime,&raw_entry->adate);
605 raw_entry->ctime_cs = (inode->i_ctime.tv_sec & 1) * 100 +
606 inode->i_ctime.tv_nsec / 10000000;
607 }
608 spin_unlock(&sbi->inode_hash_lock);
609 mark_buffer_dirty(bh);
610 if (wait)
611 err = sync_dirty_buffer(bh);
612 brelse(bh);
613 out:
614 unlock_kernel();
615 return err;
616 }
617
618 int fat_sync_inode(struct inode *inode)
619 {
620 return fat_write_inode(inode, 1);
621 }
622
623 EXPORT_SYMBOL_GPL(fat_sync_inode);
624
625 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt);
626 static const struct super_operations fat_sops = {
627 .alloc_inode = fat_alloc_inode,
628 .destroy_inode = fat_destroy_inode,
629 .write_inode = fat_write_inode,
630 .delete_inode = fat_delete_inode,
631 .put_super = fat_put_super,
632 .write_super = fat_write_super,
633 .statfs = fat_statfs,
634 .clear_inode = fat_clear_inode,
635 .remount_fs = fat_remount,
636
637 .show_options = fat_show_options,
638 };
639
640 /*
641 * a FAT file handle with fhtype 3 is
642 * 0/ i_ino - for fast, reliable lookup if still in the cache
643 * 1/ i_generation - to see if i_ino is still valid
644 * bit 0 == 0 iff directory
645 * 2/ i_pos(8-39) - if ino has changed, but still in cache
646 * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos
647 * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc
648 *
649 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum
650 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits
651 * of i_logstart is used to store the directory entry offset.
652 */
653
654 static struct dentry *fat_fh_to_dentry(struct super_block *sb,
655 struct fid *fid, int fh_len, int fh_type)
656 {
657 struct inode *inode = NULL;
658 struct dentry *result;
659 u32 *fh = fid->raw;
660
661 if (fh_len < 5 || fh_type != 3)
662 return NULL;
663
664 inode = ilookup(sb, fh[0]);
665 if (!inode || inode->i_generation != fh[1]) {
666 if (inode)
667 iput(inode);
668 inode = NULL;
669 }
670 if (!inode) {
671 loff_t i_pos;
672 int i_logstart = fh[3] & 0x0fffffff;
673
674 i_pos = (loff_t)fh[2] << 8;
675 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28);
676
677 /* try 2 - see if i_pos is in F-d-c
678 * require i_logstart to be the same
679 * Will fail if you truncate and then re-write
680 */
681
682 inode = fat_iget(sb, i_pos);
683 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) {
684 iput(inode);
685 inode = NULL;
686 }
687 }
688 if (!inode) {
689 /* For now, do nothing
690 * What we could do is:
691 * follow the file starting at fh[4], and record
692 * the ".." entry, and the name of the fh[2] entry.
693 * The follow the ".." file finding the next step up.
694 * This way we build a path to the root of
695 * the tree. If this works, we lookup the path and so
696 * get this inode into the cache.
697 * Finally try the fat_iget lookup again
698 * If that fails, then weare totally out of luck
699 * But all that is for another day
700 */
701 }
702 if (!inode)
703 return ERR_PTR(-ESTALE);
704
705
706 /* now to find a dentry.
707 * If possible, get a well-connected one
708 */
709 result = d_alloc_anon(inode);
710 if (result == NULL) {
711 iput(inode);
712 return ERR_PTR(-ENOMEM);
713 }
714 result->d_op = sb->s_root->d_op;
715 return result;
716 }
717
718 static int
719 fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable)
720 {
721 int len = *lenp;
722 struct inode *inode = de->d_inode;
723 u32 ipos_h, ipos_m, ipos_l;
724
725 if (len < 5)
726 return 255; /* no room */
727
728 ipos_h = MSDOS_I(inode)->i_pos >> 8;
729 ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24;
730 ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28;
731 *lenp = 5;
732 fh[0] = inode->i_ino;
733 fh[1] = inode->i_generation;
734 fh[2] = ipos_h;
735 fh[3] = ipos_m | MSDOS_I(inode)->i_logstart;
736 spin_lock(&de->d_lock);
737 fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart;
738 spin_unlock(&de->d_lock);
739 return 3;
740 }
741
742 static struct dentry *fat_get_parent(struct dentry *child)
743 {
744 struct buffer_head *bh;
745 struct msdos_dir_entry *de;
746 loff_t i_pos;
747 struct dentry *parent;
748 struct inode *inode;
749 int err;
750
751 lock_kernel();
752
753 err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos);
754 if (err) {
755 parent = ERR_PTR(err);
756 goto out;
757 }
758 inode = fat_build_inode(child->d_sb, de, i_pos);
759 brelse(bh);
760 if (IS_ERR(inode)) {
761 parent = ERR_CAST(inode);
762 goto out;
763 }
764 parent = d_alloc_anon(inode);
765 if (!parent) {
766 iput(inode);
767 parent = ERR_PTR(-ENOMEM);
768 }
769 out:
770 unlock_kernel();
771
772 return parent;
773 }
774
775 static const struct export_operations fat_export_ops = {
776 .encode_fh = fat_encode_fh,
777 .fh_to_dentry = fat_fh_to_dentry,
778 .get_parent = fat_get_parent,
779 };
780
781 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt)
782 {
783 struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb);
784 struct fat_mount_options *opts = &sbi->options;
785 int isvfat = opts->isvfat;
786
787 if (opts->fs_uid != 0)
788 seq_printf(m, ",uid=%u", opts->fs_uid);
789 if (opts->fs_gid != 0)
790 seq_printf(m, ",gid=%u", opts->fs_gid);
791 seq_printf(m, ",fmask=%04o", opts->fs_fmask);
792 seq_printf(m, ",dmask=%04o", opts->fs_dmask);
793 if (sbi->nls_disk)
794 seq_printf(m, ",codepage=%s", sbi->nls_disk->charset);
795 if (isvfat) {
796 if (sbi->nls_io)
797 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
798
799 switch (opts->shortname) {
800 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
801 seq_puts(m, ",shortname=win95");
802 break;
803 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
804 seq_puts(m, ",shortname=winnt");
805 break;
806 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
807 seq_puts(m, ",shortname=mixed");
808 break;
809 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
810 /* seq_puts(m, ",shortname=lower"); */
811 break;
812 default:
813 seq_puts(m, ",shortname=unknown");
814 break;
815 }
816 }
817 if (opts->name_check != 'n')
818 seq_printf(m, ",check=%c", opts->name_check);
819 if (opts->usefree)
820 seq_puts(m, ",usefree");
821 if (opts->quiet)
822 seq_puts(m, ",quiet");
823 if (opts->showexec)
824 seq_puts(m, ",showexec");
825 if (opts->sys_immutable)
826 seq_puts(m, ",sys_immutable");
827 if (!isvfat) {
828 if (opts->dotsOK)
829 seq_puts(m, ",dotsOK=yes");
830 if (opts->nocase)
831 seq_puts(m, ",nocase");
832 } else {
833 if (opts->utf8)
834 seq_puts(m, ",utf8");
835 if (opts->unicode_xlate)
836 seq_puts(m, ",uni_xlate");
837 if (!opts->numtail)
838 seq_puts(m, ",nonumtail");
839 }
840 if (sbi->options.flush)
841 seq_puts(m, ",flush");
842
843 return 0;
844 }
845
846 enum {
847 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
848 Opt_umask, Opt_dmask, Opt_fmask, Opt_codepage, Opt_usefree, Opt_nocase,
849 Opt_quiet, Opt_showexec, Opt_debug, Opt_immutable,
850 Opt_dots, Opt_nodots,
851 Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
852 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
853 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
854 Opt_obsolate, Opt_flush, Opt_err,
855 };
856
857 static match_table_t fat_tokens = {
858 {Opt_check_r, "check=relaxed"},
859 {Opt_check_s, "check=strict"},
860 {Opt_check_n, "check=normal"},
861 {Opt_check_r, "check=r"},
862 {Opt_check_s, "check=s"},
863 {Opt_check_n, "check=n"},
864 {Opt_uid, "uid=%u"},
865 {Opt_gid, "gid=%u"},
866 {Opt_umask, "umask=%o"},
867 {Opt_dmask, "dmask=%o"},
868 {Opt_fmask, "fmask=%o"},
869 {Opt_codepage, "codepage=%u"},
870 {Opt_usefree, "usefree"},
871 {Opt_nocase, "nocase"},
872 {Opt_quiet, "quiet"},
873 {Opt_showexec, "showexec"},
874 {Opt_debug, "debug"},
875 {Opt_immutable, "sys_immutable"},
876 {Opt_obsolate, "conv=binary"},
877 {Opt_obsolate, "conv=text"},
878 {Opt_obsolate, "conv=auto"},
879 {Opt_obsolate, "conv=b"},
880 {Opt_obsolate, "conv=t"},
881 {Opt_obsolate, "conv=a"},
882 {Opt_obsolate, "fat=%u"},
883 {Opt_obsolate, "blocksize=%u"},
884 {Opt_obsolate, "cvf_format=%20s"},
885 {Opt_obsolate, "cvf_options=%100s"},
886 {Opt_obsolate, "posix"},
887 {Opt_flush, "flush"},
888 {Opt_err, NULL},
889 };
890 static match_table_t msdos_tokens = {
891 {Opt_nodots, "nodots"},
892 {Opt_nodots, "dotsOK=no"},
893 {Opt_dots, "dots"},
894 {Opt_dots, "dotsOK=yes"},
895 {Opt_err, NULL}
896 };
897 static match_table_t vfat_tokens = {
898 {Opt_charset, "iocharset=%s"},
899 {Opt_shortname_lower, "shortname=lower"},
900 {Opt_shortname_win95, "shortname=win95"},
901 {Opt_shortname_winnt, "shortname=winnt"},
902 {Opt_shortname_mixed, "shortname=mixed"},
903 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */
904 {Opt_utf8_no, "utf8=no"},
905 {Opt_utf8_no, "utf8=false"},
906 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */
907 {Opt_utf8_yes, "utf8=yes"},
908 {Opt_utf8_yes, "utf8=true"},
909 {Opt_utf8_yes, "utf8"},
910 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */
911 {Opt_uni_xl_no, "uni_xlate=no"},
912 {Opt_uni_xl_no, "uni_xlate=false"},
913 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */
914 {Opt_uni_xl_yes, "uni_xlate=yes"},
915 {Opt_uni_xl_yes, "uni_xlate=true"},
916 {Opt_uni_xl_yes, "uni_xlate"},
917 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */
918 {Opt_nonumtail_no, "nonumtail=no"},
919 {Opt_nonumtail_no, "nonumtail=false"},
920 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */
921 {Opt_nonumtail_yes, "nonumtail=yes"},
922 {Opt_nonumtail_yes, "nonumtail=true"},
923 {Opt_nonumtail_yes, "nonumtail"},
924 {Opt_err, NULL}
925 };
926
927 static int parse_options(char *options, int is_vfat, int silent, int *debug,
928 struct fat_mount_options *opts)
929 {
930 char *p;
931 substring_t args[MAX_OPT_ARGS];
932 int option;
933 char *iocharset;
934
935 opts->isvfat = is_vfat;
936
937 opts->fs_uid = current->uid;
938 opts->fs_gid = current->gid;
939 opts->fs_fmask = opts->fs_dmask = current->fs->umask;
940 opts->codepage = fat_default_codepage;
941 opts->iocharset = fat_default_iocharset;
942 if (is_vfat)
943 opts->shortname = VFAT_SFN_DISPLAY_LOWER|VFAT_SFN_CREATE_WIN95;
944 else
945 opts->shortname = 0;
946 opts->name_check = 'n';
947 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0;
948 opts->utf8 = opts->unicode_xlate = 0;
949 opts->numtail = 1;
950 opts->usefree = opts->nocase = 0;
951 *debug = 0;
952
953 if (!options)
954 return 0;
955
956 while ((p = strsep(&options, ",")) != NULL) {
957 int token;
958 if (!*p)
959 continue;
960
961 token = match_token(p, fat_tokens, args);
962 if (token == Opt_err) {
963 if (is_vfat)
964 token = match_token(p, vfat_tokens, args);
965 else
966 token = match_token(p, msdos_tokens, args);
967 }
968 switch (token) {
969 case Opt_check_s:
970 opts->name_check = 's';
971 break;
972 case Opt_check_r:
973 opts->name_check = 'r';
974 break;
975 case Opt_check_n:
976 opts->name_check = 'n';
977 break;
978 case Opt_usefree:
979 opts->usefree = 1;
980 break;
981 case Opt_nocase:
982 if (!is_vfat)
983 opts->nocase = 1;
984 else {
985 /* for backward compatibility */
986 opts->shortname = VFAT_SFN_DISPLAY_WIN95
987 | VFAT_SFN_CREATE_WIN95;
988 }
989 break;
990 case Opt_quiet:
991 opts->quiet = 1;
992 break;
993 case Opt_showexec:
994 opts->showexec = 1;
995 break;
996 case Opt_debug:
997 *debug = 1;
998 break;
999 case Opt_immutable:
1000 opts->sys_immutable = 1;
1001 break;
1002 case Opt_uid:
1003 if (match_int(&args[0], &option))
1004 return 0;
1005 opts->fs_uid = option;
1006 break;
1007 case Opt_gid:
1008 if (match_int(&args[0], &option))
1009 return 0;
1010 opts->fs_gid = option;
1011 break;
1012 case Opt_umask:
1013 if (match_octal(&args[0], &option))
1014 return 0;
1015 opts->fs_fmask = opts->fs_dmask = option;
1016 break;
1017 case Opt_dmask:
1018 if (match_octal(&args[0], &option))
1019 return 0;
1020 opts->fs_dmask = option;
1021 break;
1022 case Opt_fmask:
1023 if (match_octal(&args[0], &option))
1024 return 0;
1025 opts->fs_fmask = option;
1026 break;
1027 case Opt_codepage:
1028 if (match_int(&args[0], &option))
1029 return 0;
1030 opts->codepage = option;
1031 break;
1032 case Opt_flush:
1033 opts->flush = 1;
1034 break;
1035
1036 /* msdos specific */
1037 case Opt_dots:
1038 opts->dotsOK = 1;
1039 break;
1040 case Opt_nodots:
1041 opts->dotsOK = 0;
1042 break;
1043
1044 /* vfat specific */
1045 case Opt_charset:
1046 if (opts->iocharset != fat_default_iocharset)
1047 kfree(opts->iocharset);
1048 iocharset = match_strdup(&args[0]);
1049 if (!iocharset)
1050 return -ENOMEM;
1051 opts->iocharset = iocharset;
1052 break;
1053 case Opt_shortname_lower:
1054 opts->shortname = VFAT_SFN_DISPLAY_LOWER
1055 | VFAT_SFN_CREATE_WIN95;
1056 break;
1057 case Opt_shortname_win95:
1058 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1059 | VFAT_SFN_CREATE_WIN95;
1060 break;
1061 case Opt_shortname_winnt:
1062 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1063 | VFAT_SFN_CREATE_WINNT;
1064 break;
1065 case Opt_shortname_mixed:
1066 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1067 | VFAT_SFN_CREATE_WIN95;
1068 break;
1069 case Opt_utf8_no: /* 0 or no or false */
1070 opts->utf8 = 0;
1071 break;
1072 case Opt_utf8_yes: /* empty or 1 or yes or true */
1073 opts->utf8 = 1;
1074 break;
1075 case Opt_uni_xl_no: /* 0 or no or false */
1076 opts->unicode_xlate = 0;
1077 break;
1078 case Opt_uni_xl_yes: /* empty or 1 or yes or true */
1079 opts->unicode_xlate = 1;
1080 break;
1081 case Opt_nonumtail_no: /* 0 or no or false */
1082 opts->numtail = 1; /* negated option */
1083 break;
1084 case Opt_nonumtail_yes: /* empty or 1 or yes or true */
1085 opts->numtail = 0; /* negated option */
1086 break;
1087
1088 /* obsolete mount options */
1089 case Opt_obsolate:
1090 printk(KERN_INFO "FAT: \"%s\" option is obsolete, "
1091 "not supported now\n", p);
1092 break;
1093 /* unknown option */
1094 default:
1095 if (!silent) {
1096 printk(KERN_ERR
1097 "FAT: Unrecognized mount option \"%s\" "
1098 "or missing value\n", p);
1099 }
1100 return -EINVAL;
1101 }
1102 }
1103 /* UTF-8 doesn't provide FAT semantics */
1104 if (!strcmp(opts->iocharset, "utf8")) {
1105 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset"
1106 " for FAT filesystems, filesystem will be case sensitive!\n");
1107 }
1108
1109 if (opts->unicode_xlate)
1110 opts->utf8 = 0;
1111
1112 return 0;
1113 }
1114
1115 static int fat_read_root(struct inode *inode)
1116 {
1117 struct super_block *sb = inode->i_sb;
1118 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1119 int error;
1120
1121 MSDOS_I(inode)->i_pos = 0;
1122 inode->i_uid = sbi->options.fs_uid;
1123 inode->i_gid = sbi->options.fs_gid;
1124 inode->i_version++;
1125 inode->i_generation = 0;
1126 inode->i_mode = (S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR;
1127 inode->i_op = sbi->dir_ops;
1128 inode->i_fop = &fat_dir_operations;
1129 if (sbi->fat_bits == 32) {
1130 MSDOS_I(inode)->i_start = sbi->root_cluster;
1131 error = fat_calc_dir_size(inode);
1132 if (error < 0)
1133 return error;
1134 } else {
1135 MSDOS_I(inode)->i_start = 0;
1136 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1137 }
1138 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1139 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1140 MSDOS_I(inode)->i_logstart = 0;
1141 MSDOS_I(inode)->mmu_private = inode->i_size;
1142
1143 MSDOS_I(inode)->i_attrs = ATTR_NONE;
1144 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1145 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1146 inode->i_nlink = fat_subdirs(inode)+2;
1147
1148 return 0;
1149 }
1150
1151 /*
1152 * Read the super block of an MS-DOS FS.
1153 */
1154 int fat_fill_super(struct super_block *sb, void *data, int silent,
1155 const struct inode_operations *fs_dir_inode_ops, int isvfat)
1156 {
1157 struct inode *root_inode = NULL;
1158 struct buffer_head *bh;
1159 struct fat_boot_sector *b;
1160 struct msdos_sb_info *sbi;
1161 u16 logical_sector_size;
1162 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1163 int debug;
1164 unsigned int media;
1165 long error;
1166 char buf[50];
1167
1168 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1169 if (!sbi)
1170 return -ENOMEM;
1171 sb->s_fs_info = sbi;
1172
1173 sb->s_flags |= MS_NODIRATIME;
1174 sb->s_magic = MSDOS_SUPER_MAGIC;
1175 sb->s_op = &fat_sops;
1176 sb->s_export_op = &fat_export_ops;
1177 sbi->dir_ops = fs_dir_inode_ops;
1178
1179 error = parse_options(data, isvfat, silent, &debug, &sbi->options);
1180 if (error)
1181 goto out_fail;
1182
1183 error = -EIO;
1184 sb_min_blocksize(sb, 512);
1185 bh = sb_bread(sb, 0);
1186 if (bh == NULL) {
1187 printk(KERN_ERR "FAT: unable to read boot sector\n");
1188 goto out_fail;
1189 }
1190
1191 b = (struct fat_boot_sector *) bh->b_data;
1192 if (!b->reserved) {
1193 if (!silent)
1194 printk(KERN_ERR "FAT: bogus number of reserved sectors\n");
1195 brelse(bh);
1196 goto out_invalid;
1197 }
1198 if (!b->fats) {
1199 if (!silent)
1200 printk(KERN_ERR "FAT: bogus number of FAT structure\n");
1201 brelse(bh);
1202 goto out_invalid;
1203 }
1204
1205 /*
1206 * Earlier we checked here that b->secs_track and b->head are nonzero,
1207 * but it turns out valid FAT filesystems can have zero there.
1208 */
1209
1210 media = b->media;
1211 if (!FAT_VALID_MEDIA(media)) {
1212 if (!silent)
1213 printk(KERN_ERR "FAT: invalid media value (0x%02x)\n",
1214 media);
1215 brelse(bh);
1216 goto out_invalid;
1217 }
1218 logical_sector_size =
1219 le16_to_cpu(get_unaligned((__le16 *)&b->sector_size));
1220 if (!is_power_of_2(logical_sector_size)
1221 || (logical_sector_size < 512)
1222 || (PAGE_CACHE_SIZE < logical_sector_size)) {
1223 if (!silent)
1224 printk(KERN_ERR "FAT: bogus logical sector size %u\n",
1225 logical_sector_size);
1226 brelse(bh);
1227 goto out_invalid;
1228 }
1229 sbi->sec_per_clus = b->sec_per_clus;
1230 if (!is_power_of_2(sbi->sec_per_clus)) {
1231 if (!silent)
1232 printk(KERN_ERR "FAT: bogus sectors per cluster %u\n",
1233 sbi->sec_per_clus);
1234 brelse(bh);
1235 goto out_invalid;
1236 }
1237
1238 if (logical_sector_size < sb->s_blocksize) {
1239 printk(KERN_ERR "FAT: logical sector size too small for device"
1240 " (logical sector size = %u)\n", logical_sector_size);
1241 brelse(bh);
1242 goto out_fail;
1243 }
1244 if (logical_sector_size > sb->s_blocksize) {
1245 brelse(bh);
1246
1247 if (!sb_set_blocksize(sb, logical_sector_size)) {
1248 printk(KERN_ERR "FAT: unable to set blocksize %u\n",
1249 logical_sector_size);
1250 goto out_fail;
1251 }
1252 bh = sb_bread(sb, 0);
1253 if (bh == NULL) {
1254 printk(KERN_ERR "FAT: unable to read boot sector"
1255 " (logical sector size = %lu)\n",
1256 sb->s_blocksize);
1257 goto out_fail;
1258 }
1259 b = (struct fat_boot_sector *) bh->b_data;
1260 }
1261
1262 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1263 sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1264 sbi->fats = b->fats;
1265 sbi->fat_bits = 0; /* Don't know yet */
1266 sbi->fat_start = le16_to_cpu(b->reserved);
1267 sbi->fat_length = le16_to_cpu(b->fat_length);
1268 sbi->root_cluster = 0;
1269 sbi->free_clusters = -1; /* Don't know yet */
1270 sbi->prev_free = FAT_START_ENT;
1271
1272 if (!sbi->fat_length && b->fat32_length) {
1273 struct fat_boot_fsinfo *fsinfo;
1274 struct buffer_head *fsinfo_bh;
1275
1276 /* Must be FAT32 */
1277 sbi->fat_bits = 32;
1278 sbi->fat_length = le32_to_cpu(b->fat32_length);
1279 sbi->root_cluster = le32_to_cpu(b->root_cluster);
1280
1281 sb->s_maxbytes = 0xffffffff;
1282
1283 /* MC - if info_sector is 0, don't multiply by 0 */
1284 sbi->fsinfo_sector = le16_to_cpu(b->info_sector);
1285 if (sbi->fsinfo_sector == 0)
1286 sbi->fsinfo_sector = 1;
1287
1288 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1289 if (fsinfo_bh == NULL) {
1290 printk(KERN_ERR "FAT: bread failed, FSINFO block"
1291 " (sector = %lu)\n", sbi->fsinfo_sector);
1292 brelse(bh);
1293 goto out_fail;
1294 }
1295
1296 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1297 if (!IS_FSINFO(fsinfo)) {
1298 printk(KERN_WARNING "FAT: Invalid FSINFO signature: "
1299 "0x%08x, 0x%08x (sector = %lu)\n",
1300 le32_to_cpu(fsinfo->signature1),
1301 le32_to_cpu(fsinfo->signature2),
1302 sbi->fsinfo_sector);
1303 } else {
1304 if (sbi->options.usefree)
1305 sbi->free_clusters =
1306 le32_to_cpu(fsinfo->free_clusters);
1307 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1308 }
1309
1310 brelse(fsinfo_bh);
1311 }
1312
1313 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1314 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1315
1316 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1317 sbi->dir_entries =
1318 le16_to_cpu(get_unaligned((__le16 *)&b->dir_entries));
1319 if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1320 if (!silent)
1321 printk(KERN_ERR "FAT: bogus directroy-entries per block"
1322 " (%u)\n", sbi->dir_entries);
1323 brelse(bh);
1324 goto out_invalid;
1325 }
1326
1327 rootdir_sectors = sbi->dir_entries
1328 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1329 sbi->data_start = sbi->dir_start + rootdir_sectors;
1330 total_sectors = le16_to_cpu(get_unaligned((__le16 *)&b->sectors));
1331 if (total_sectors == 0)
1332 total_sectors = le32_to_cpu(b->total_sect);
1333
1334 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1335
1336 if (sbi->fat_bits != 32)
1337 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1338
1339 /* check that FAT table does not overflow */
1340 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1341 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1342 if (total_clusters > MAX_FAT(sb)) {
1343 if (!silent)
1344 printk(KERN_ERR "FAT: count of clusters too big (%u)\n",
1345 total_clusters);
1346 brelse(bh);
1347 goto out_invalid;
1348 }
1349
1350 sbi->max_cluster = total_clusters + FAT_START_ENT;
1351 /* check the free_clusters, it's not necessarily correct */
1352 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1353 sbi->free_clusters = -1;
1354 /* check the prev_free, it's not necessarily correct */
1355 sbi->prev_free %= sbi->max_cluster;
1356 if (sbi->prev_free < FAT_START_ENT)
1357 sbi->prev_free = FAT_START_ENT;
1358
1359 brelse(bh);
1360
1361 /* set up enough so that it can read an inode */
1362 fat_hash_init(sb);
1363 fat_ent_access_init(sb);
1364
1365 /*
1366 * The low byte of FAT's first entry must have same value with
1367 * media-field. But in real world, too many devices is
1368 * writing wrong value. So, removed that validity check.
1369 *
1370 * if (FAT_FIRST_ENT(sb, media) != first)
1371 */
1372
1373 error = -EINVAL;
1374 sprintf(buf, "cp%d", sbi->options.codepage);
1375 sbi->nls_disk = load_nls(buf);
1376 if (!sbi->nls_disk) {
1377 printk(KERN_ERR "FAT: codepage %s not found\n", buf);
1378 goto out_fail;
1379 }
1380
1381 /* FIXME: utf8 is using iocharset for upper/lower conversion */
1382 if (sbi->options.isvfat) {
1383 sbi->nls_io = load_nls(sbi->options.iocharset);
1384 if (!sbi->nls_io) {
1385 printk(KERN_ERR "FAT: IO charset %s not found\n",
1386 sbi->options.iocharset);
1387 goto out_fail;
1388 }
1389 }
1390
1391 error = -ENOMEM;
1392 root_inode = new_inode(sb);
1393 if (!root_inode)
1394 goto out_fail;
1395 root_inode->i_ino = MSDOS_ROOT_INO;
1396 root_inode->i_version = 1;
1397 error = fat_read_root(root_inode);
1398 if (error < 0)
1399 goto out_fail;
1400 error = -ENOMEM;
1401 insert_inode_hash(root_inode);
1402 sb->s_root = d_alloc_root(root_inode);
1403 if (!sb->s_root) {
1404 printk(KERN_ERR "FAT: get root inode failed\n");
1405 goto out_fail;
1406 }
1407
1408 return 0;
1409
1410 out_invalid:
1411 error = -EINVAL;
1412 if (!silent)
1413 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem"
1414 " on dev %s.\n", sb->s_id);
1415
1416 out_fail:
1417 if (root_inode)
1418 iput(root_inode);
1419 if (sbi->nls_io)
1420 unload_nls(sbi->nls_io);
1421 if (sbi->nls_disk)
1422 unload_nls(sbi->nls_disk);
1423 if (sbi->options.iocharset != fat_default_iocharset)
1424 kfree(sbi->options.iocharset);
1425 sb->s_fs_info = NULL;
1426 kfree(sbi);
1427 return error;
1428 }
1429
1430 EXPORT_SYMBOL_GPL(fat_fill_super);
1431
1432 /*
1433 * helper function for fat_flush_inodes. This writes both the inode
1434 * and the file data blocks, waiting for in flight data blocks before
1435 * the start of the call. It does not wait for any io started
1436 * during the call
1437 */
1438 static int writeback_inode(struct inode *inode)
1439 {
1440
1441 int ret;
1442 struct address_space *mapping = inode->i_mapping;
1443 struct writeback_control wbc = {
1444 .sync_mode = WB_SYNC_NONE,
1445 .nr_to_write = 0,
1446 };
1447 /* if we used WB_SYNC_ALL, sync_inode waits for the io for the
1448 * inode to finish. So WB_SYNC_NONE is sent down to sync_inode
1449 * and filemap_fdatawrite is used for the data blocks
1450 */
1451 ret = sync_inode(inode, &wbc);
1452 if (!ret)
1453 ret = filemap_fdatawrite(mapping);
1454 return ret;
1455 }
1456
1457 /*
1458 * write data and metadata corresponding to i1 and i2. The io is
1459 * started but we do not wait for any of it to finish.
1460 *
1461 * filemap_flush is used for the block device, so if there is a dirty
1462 * page for a block already in flight, we will not wait and start the
1463 * io over again
1464 */
1465 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1466 {
1467 int ret = 0;
1468 if (!MSDOS_SB(sb)->options.flush)
1469 return 0;
1470 if (i1)
1471 ret = writeback_inode(i1);
1472 if (!ret && i2)
1473 ret = writeback_inode(i2);
1474 if (!ret) {
1475 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
1476 ret = filemap_flush(mapping);
1477 }
1478 return ret;
1479 }
1480 EXPORT_SYMBOL_GPL(fat_flush_inodes);
1481
1482 static int __init init_fat_fs(void)
1483 {
1484 int err;
1485
1486 err = fat_cache_init();
1487 if (err)
1488 return err;
1489
1490 err = fat_init_inodecache();
1491 if (err)
1492 goto failed;
1493
1494 return 0;
1495
1496 failed:
1497 fat_cache_destroy();
1498 return err;
1499 }
1500
1501 static void __exit exit_fat_fs(void)
1502 {
1503 fat_cache_destroy();
1504 fat_destroy_inodecache();
1505 }
1506
1507 module_init(init_fat_fs)
1508 module_exit(exit_fat_fs)
1509
1510 MODULE_LICENSE("GPL");
WRT350N Kernel Patches