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MX35: Add basic support for MX35PDK board
[linux-2.6.git] / fs / fat / inode.c
blob296785a0dec8068471d5e5764fd41cea1bcc9903
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/pagemap.h>
20 #include <linux/mpage.h>
21 #include <linux/buffer_head.h>
22 #include <linux/exportfs.h>
23 #include <linux/mount.h>
24 #include <linux/vfs.h>
25 #include <linux/parser.h>
26 #include <linux/uio.h>
27 #include <linux/writeback.h>
28 #include <linux/log2.h>
29 #include <linux/hash.h>
30 #include <asm/unaligned.h>
31 #include "fat.h"
32
33 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET
34 /* if user don't select VFAT, this is undefined. */
35 #define CONFIG_FAT_DEFAULT_IOCHARSET ""
36 #endif
37
38 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
39 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
40
41
42 static int fat_add_cluster(struct inode *inode)
43 {
44 int err, cluster;
45
46 err = fat_alloc_clusters(inode, &cluster, 1);
47 if (err)
48 return err;
49 /* FIXME: this cluster should be added after data of this
50 * cluster is writed */
51 err = fat_chain_add(inode, cluster, 1);
52 if (err)
53 fat_free_clusters(inode, cluster);
54 return err;
55 }
56
57 static inline int __fat_get_block(struct inode *inode, sector_t iblock,
58 unsigned long *max_blocks,
59 struct buffer_head *bh_result, int create)
60 {
61 struct super_block *sb = inode->i_sb;
62 struct msdos_sb_info *sbi = MSDOS_SB(sb);
63 unsigned long mapped_blocks;
64 sector_t phys;
65 int err, offset;
66
67 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
68 if (err)
69 return err;
70 if (phys) {
71 map_bh(bh_result, sb, phys);
72 *max_blocks = min(mapped_blocks, *max_blocks);
73 return 0;
74 }
75 if (!create)
76 return 0;
77
78 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
79 fat_fs_panic(sb, "corrupted file size (i_pos %lld, %lld)",
80 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
81 return -EIO;
82 }
83
84 offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
85 if (!offset) {
86 /* TODO: multiple cluster allocation would be desirable. */
87 err = fat_add_cluster(inode);
88 if (err)
89 return err;
90 }
91 /* available blocks on this cluster */
92 mapped_blocks = sbi->sec_per_clus - offset;
93
94 *max_blocks = min(mapped_blocks, *max_blocks);
95 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
96
97 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
98 if (err)
99 return err;
100
101 BUG_ON(!phys);
102 BUG_ON(*max_blocks != mapped_blocks);
103 set_buffer_new(bh_result);
104 map_bh(bh_result, sb, phys);
105
106 return 0;
107 }
108
109 static int fat_get_block(struct inode *inode, sector_t iblock,
110 struct buffer_head *bh_result, int create)
111 {
112 struct super_block *sb = inode->i_sb;
113 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
114 int err;
115
116 err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create);
117 if (err)
118 return err;
119 bh_result->b_size = max_blocks << sb->s_blocksize_bits;
120 return 0;
121 }
122
123 static int fat_writepage(struct page *page, struct writeback_control *wbc)
124 {
125 return block_write_full_page(page, fat_get_block, wbc);
126 }
127
128 static int fat_writepages(struct address_space *mapping,
129 struct writeback_control *wbc)
130 {
131 return mpage_writepages(mapping, wbc, fat_get_block);
132 }
133
134 static int fat_readpage(struct file *file, struct page *page)
135 {
136 return mpage_readpage(page, fat_get_block);
137 }
138
139 static int fat_readpages(struct file *file, struct address_space *mapping,
140 struct list_head *pages, unsigned nr_pages)
141 {
142 return mpage_readpages(mapping, pages, nr_pages, fat_get_block);
143 }
144
145 static int fat_write_begin(struct file *file, struct address_space *mapping,
146 loff_t pos, unsigned len, unsigned flags,
147 struct page **pagep, void **fsdata)
148 {
149 *pagep = NULL;
150 return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
151 fat_get_block,
152 &MSDOS_I(mapping->host)->mmu_private);
153 }
154
155 static int fat_write_end(struct file *file, struct address_space *mapping,
156 loff_t pos, unsigned len, unsigned copied,
157 struct page *pagep, void *fsdata)
158 {
159 struct inode *inode = mapping->host;
160 int err;
161 err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
162 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
163 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
164 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
165 mark_inode_dirty(inode);
166 }
167 return err;
168 }
169
170 static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
171 const struct iovec *iov,
172 loff_t offset, unsigned long nr_segs)
173 {
174 struct file *file = iocb->ki_filp;
175 struct inode *inode = file->f_mapping->host;
176
177 if (rw == WRITE) {
178 /*
179 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
180 * so we need to update the ->mmu_private to block boundary.
181 *
182 * But we must fill the remaining area or hole by nul for
183 * updating ->mmu_private.
184 *
185 * Return 0, and fallback to normal buffered write.
186 */
187 loff_t size = offset + iov_length(iov, nr_segs);
188 if (MSDOS_I(inode)->mmu_private < size)
189 return 0;
190 }
191
192 /*
193 * FAT need to use the DIO_LOCKING for avoiding the race
194 * condition of fat_get_block() and ->truncate().
195 */
196 return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
197 offset, nr_segs, fat_get_block, NULL);
198 }
199
200 static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
201 {
202 sector_t blocknr;
203
204 /* fat_get_cluster() assumes the requested blocknr isn't truncated. */
205 down_read(&mapping->host->i_alloc_sem);
206 blocknr = generic_block_bmap(mapping, block, fat_get_block);
207 up_read(&mapping->host->i_alloc_sem);
208
209 return blocknr;
210 }
211
212 static const struct address_space_operations fat_aops = {
213 .readpage = fat_readpage,
214 .readpages = fat_readpages,
215 .writepage = fat_writepage,
216 .writepages = fat_writepages,
217 .sync_page = block_sync_page,
218 .write_begin = fat_write_begin,
219 .write_end = fat_write_end,
220 .direct_IO = fat_direct_IO,
221 .bmap = _fat_bmap
222 };
223
224 /*
225 * New FAT inode stuff. We do the following:
226 * a) i_ino is constant and has nothing with on-disk location.
227 * b) FAT manages its own cache of directory entries.
228 * c) *This* cache is indexed by on-disk location.
229 * d) inode has an associated directory entry, all right, but
230 * it may be unhashed.
231 * e) currently entries are stored within struct inode. That should
232 * change.
233 * f) we deal with races in the following way:
234 * 1. readdir() and lookup() do FAT-dir-cache lookup.
235 * 2. rename() unhashes the F-d-c entry and rehashes it in
236 * a new place.
237 * 3. unlink() and rmdir() unhash F-d-c entry.
238 * 4. fat_write_inode() checks whether the thing is unhashed.
239 * If it is we silently return. If it isn't we do bread(),
240 * check if the location is still valid and retry if it
241 * isn't. Otherwise we do changes.
242 * 5. Spinlock is used to protect hash/unhash/location check/lookup
243 * 6. fat_clear_inode() unhashes the F-d-c entry.
244 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry
245 * and consider negative result as cache miss.
246 */
247
248 static void fat_hash_init(struct super_block *sb)
249 {
250 struct msdos_sb_info *sbi = MSDOS_SB(sb);
251 int i;
252
253 spin_lock_init(&sbi->inode_hash_lock);
254 for (i = 0; i < FAT_HASH_SIZE; i++)
255 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
256 }
257
258 static inline unsigned long fat_hash(loff_t i_pos)
259 {
260 return hash_32(i_pos, FAT_HASH_BITS);
261 }
262
263 void fat_attach(struct inode *inode, loff_t i_pos)
264 {
265 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
266 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
267
268 spin_lock(&sbi->inode_hash_lock);
269 MSDOS_I(inode)->i_pos = i_pos;
270 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
271 spin_unlock(&sbi->inode_hash_lock);
272 }
273 EXPORT_SYMBOL_GPL(fat_attach);
274
275 void fat_detach(struct inode *inode)
276 {
277 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
278 spin_lock(&sbi->inode_hash_lock);
279 MSDOS_I(inode)->i_pos = 0;
280 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
281 spin_unlock(&sbi->inode_hash_lock);
282 }
283 EXPORT_SYMBOL_GPL(fat_detach);
284
285 struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
286 {
287 struct msdos_sb_info *sbi = MSDOS_SB(sb);
288 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
289 struct hlist_node *_p;
290 struct msdos_inode_info *i;
291 struct inode *inode = NULL;
292
293 spin_lock(&sbi->inode_hash_lock);
294 hlist_for_each_entry(i, _p, head, i_fat_hash) {
295 BUG_ON(i->vfs_inode.i_sb != sb);
296 if (i->i_pos != i_pos)
297 continue;
298 inode = igrab(&i->vfs_inode);
299 if (inode)
300 break;
301 }
302 spin_unlock(&sbi->inode_hash_lock);
303 return inode;
304 }
305
306 static int is_exec(unsigned char *extension)
307 {
308 unsigned char *exe_extensions = "EXECOMBAT", *walk;
309
310 for (walk = exe_extensions; *walk; walk += 3)
311 if (!strncmp(extension, walk, 3))
312 return 1;
313 return 0;
314 }
315
316 static int fat_calc_dir_size(struct inode *inode)
317 {
318 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
319 int ret, fclus, dclus;
320
321 inode->i_size = 0;
322 if (MSDOS_I(inode)->i_start == 0)
323 return 0;
324
325 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
326 if (ret < 0)
327 return ret;
328 inode->i_size = (fclus + 1) << sbi->cluster_bits;
329
330 return 0;
331 }
332
333 /* doesn't deal with root inode */
334 static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
335 {
336 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
337 int error;
338
339 MSDOS_I(inode)->i_pos = 0;
340 inode->i_uid = sbi->options.fs_uid;
341 inode->i_gid = sbi->options.fs_gid;
342 inode->i_version++;
343 inode->i_generation = get_seconds();
344
345 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
346 inode->i_generation &= ~1;
347 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
348 inode->i_op = sbi->dir_ops;
349 inode->i_fop = &fat_dir_operations;
350
351 MSDOS_I(inode)->i_start = le16_to_cpu(de->start);
352 if (sbi->fat_bits == 32)
353 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16);
354
355 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
356 error = fat_calc_dir_size(inode);
357 if (error < 0)
358 return error;
359 MSDOS_I(inode)->mmu_private = inode->i_size;
360
361 inode->i_nlink = fat_subdirs(inode);
362 } else { /* not a directory */
363 inode->i_generation |= 1;
364 inode->i_mode = fat_make_mode(sbi, de->attr,
365 ((sbi->options.showexec && !is_exec(de->name + 8))
366 ? S_IRUGO|S_IWUGO : S_IRWXUGO));
367 MSDOS_I(inode)->i_start = le16_to_cpu(de->start);
368 if (sbi->fat_bits == 32)
369 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16);
370
371 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
372 inode->i_size = le32_to_cpu(de->size);
373 inode->i_op = &fat_file_inode_operations;
374 inode->i_fop = &fat_file_operations;
375 inode->i_mapping->a_ops = &fat_aops;
376 MSDOS_I(inode)->mmu_private = inode->i_size;
377 }
378 if (de->attr & ATTR_SYS) {
379 if (sbi->options.sys_immutable)
380 inode->i_flags |= S_IMMUTABLE;
381 }
382 fat_save_attrs(inode, de->attr);
383
384 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
385 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
386
387 fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0);
388 if (sbi->options.isvfat) {
389 fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime,
390 de->cdate, de->ctime_cs);
391 fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
392 } else
393 inode->i_ctime = inode->i_atime = inode->i_mtime;
394
395 return 0;
396 }
397
398 struct inode *fat_build_inode(struct super_block *sb,
399 struct msdos_dir_entry *de, loff_t i_pos)
400 {
401 struct inode *inode;
402 int err;
403
404 inode = fat_iget(sb, i_pos);
405 if (inode)
406 goto out;
407 inode = new_inode(sb);
408 if (!inode) {
409 inode = ERR_PTR(-ENOMEM);
410 goto out;
411 }
412 inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
413 inode->i_version = 1;
414 err = fat_fill_inode(inode, de);
415 if (err) {
416 iput(inode);
417 inode = ERR_PTR(err);
418 goto out;
419 }
420 fat_attach(inode, i_pos);
421 insert_inode_hash(inode);
422 out:
423 return inode;
424 }
425
426 EXPORT_SYMBOL_GPL(fat_build_inode);
427
428 static void fat_delete_inode(struct inode *inode)
429 {
430 truncate_inode_pages(&inode->i_data, 0);
431 inode->i_size = 0;
432 fat_truncate(inode);
433 clear_inode(inode);
434 }
435
436 static void fat_clear_inode(struct inode *inode)
437 {
438 fat_cache_inval_inode(inode);
439 fat_detach(inode);
440 }
441
442 static void fat_write_super(struct super_block *sb)
443 {
444 sb->s_dirt = 0;
445
446 if (!(sb->s_flags & MS_RDONLY))
447 fat_clusters_flush(sb);
448 }
449
450 static void fat_put_super(struct super_block *sb)
451 {
452 struct msdos_sb_info *sbi = MSDOS_SB(sb);
453
454 if (sbi->nls_disk) {
455 unload_nls(sbi->nls_disk);
456 sbi->nls_disk = NULL;
457 sbi->options.codepage = fat_default_codepage;
458 }
459 if (sbi->nls_io) {
460 unload_nls(sbi->nls_io);
461 sbi->nls_io = NULL;
462 }
463 if (sbi->options.iocharset != fat_default_iocharset) {
464 kfree(sbi->options.iocharset);
465 sbi->options.iocharset = fat_default_iocharset;
466 }
467
468 sb->s_fs_info = NULL;
469 kfree(sbi);
470 }
471
472 static struct kmem_cache *fat_inode_cachep;
473
474 static struct inode *fat_alloc_inode(struct super_block *sb)
475 {
476 struct msdos_inode_info *ei;
477 ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
478 if (!ei)
479 return NULL;
480 return &ei->vfs_inode;
481 }
482
483 static void fat_destroy_inode(struct inode *inode)
484 {
485 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
486 }
487
488 static void init_once(void *foo)
489 {
490 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
491
492 spin_lock_init(&ei->cache_lru_lock);
493 ei->nr_caches = 0;
494 ei->cache_valid_id = FAT_CACHE_VALID + 1;
495 INIT_LIST_HEAD(&ei->cache_lru);
496 INIT_HLIST_NODE(&ei->i_fat_hash);
497 inode_init_once(&ei->vfs_inode);
498 }
499
500 static int __init fat_init_inodecache(void)
501 {
502 fat_inode_cachep = kmem_cache_create("fat_inode_cache",
503 sizeof(struct msdos_inode_info),
504 0, (SLAB_RECLAIM_ACCOUNT|
505 SLAB_MEM_SPREAD),
506 init_once);
507 if (fat_inode_cachep == NULL)
508 return -ENOMEM;
509 return 0;
510 }
511
512 static void __exit fat_destroy_inodecache(void)
513 {
514 kmem_cache_destroy(fat_inode_cachep);
515 }
516
517 static int fat_remount(struct super_block *sb, int *flags, char *data)
518 {
519 struct msdos_sb_info *sbi = MSDOS_SB(sb);
520 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME);
521 return 0;
522 }
523
524 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
525 {
526 struct super_block *sb = dentry->d_sb;
527 struct msdos_sb_info *sbi = MSDOS_SB(sb);
528 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
529
530 /* If the count of free cluster is still unknown, counts it here. */
531 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
532 int err = fat_count_free_clusters(dentry->d_sb);
533 if (err)
534 return err;
535 }
536
537 buf->f_type = dentry->d_sb->s_magic;
538 buf->f_bsize = sbi->cluster_size;
539 buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
540 buf->f_bfree = sbi->free_clusters;
541 buf->f_bavail = sbi->free_clusters;
542 buf->f_fsid.val[0] = (u32)id;
543 buf->f_fsid.val[1] = (u32)(id >> 32);
544 buf->f_namelen = sbi->options.isvfat ? 260 : 12;
545
546 return 0;
547 }
548
549 static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi,
550 struct inode *inode)
551 {
552 loff_t i_pos;
553 #if BITS_PER_LONG == 32
554 spin_lock(&sbi->inode_hash_lock);
555 #endif
556 i_pos = MSDOS_I(inode)->i_pos;
557 #if BITS_PER_LONG == 32
558 spin_unlock(&sbi->inode_hash_lock);
559 #endif
560 return i_pos;
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;
571
572 if (inode->i_ino == MSDOS_ROOT_INO)
573 return 0;
574
575 retry:
576 i_pos = fat_i_pos_read(sbi, inode);
577 if (!i_pos)
578 return 0;
579
580 bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits);
581 if (!bh) {
582 printk(KERN_ERR "FAT: unable to read inode block "
583 "for updating (i_pos %lld)\n", i_pos);
584 return -EIO;
585 }
586 spin_lock(&sbi->inode_hash_lock);
587 if (i_pos != MSDOS_I(inode)->i_pos) {
588 spin_unlock(&sbi->inode_hash_lock);
589 brelse(bh);
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_make_attrs(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_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
603 &raw_entry->date, NULL);
604 if (sbi->options.isvfat) {
605 __le16 atime;
606 fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime,
607 &raw_entry->cdate, &raw_entry->ctime_cs);
608 fat_time_unix2fat(sbi, &inode->i_atime, &atime,
609 &raw_entry->adate, NULL);
610 }
611 spin_unlock(&sbi->inode_hash_lock);
612 mark_buffer_dirty(bh);
613 err = 0;
614 if (wait)
615 err = sync_dirty_buffer(bh);
616 brelse(bh);
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 const 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 .show_options = fat_show_options,
640 };
641
642 /*
643 * a FAT file handle with fhtype 3 is
644 * 0/ i_ino - for fast, reliable lookup if still in the cache
645 * 1/ i_generation - to see if i_ino is still valid
646 * bit 0 == 0 iff directory
647 * 2/ i_pos(8-39) - if ino has changed, but still in cache
648 * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos
649 * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc
650 *
651 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum
652 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits
653 * of i_logstart is used to store the directory entry offset.
654 */
655
656 static struct dentry *fat_fh_to_dentry(struct super_block *sb,
657 struct fid *fid, int fh_len, int fh_type)
658 {
659 struct inode *inode = NULL;
660 struct dentry *result;
661 u32 *fh = fid->raw;
662
663 if (fh_len < 5 || fh_type != 3)
664 return NULL;
665
666 inode = ilookup(sb, fh[0]);
667 if (!inode || inode->i_generation != fh[1]) {
668 if (inode)
669 iput(inode);
670 inode = NULL;
671 }
672 if (!inode) {
673 loff_t i_pos;
674 int i_logstart = fh[3] & 0x0fffffff;
675
676 i_pos = (loff_t)fh[2] << 8;
677 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28);
678
679 /* try 2 - see if i_pos is in F-d-c
680 * require i_logstart to be the same
681 * Will fail if you truncate and then re-write
682 */
683
684 inode = fat_iget(sb, i_pos);
685 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) {
686 iput(inode);
687 inode = NULL;
688 }
689 }
690
691 /*
692 * For now, do nothing if the inode is not found.
693 *
694 * What we could do is:
695 *
696 * - follow the file starting at fh[4], and record the ".." entry,
697 * and the name of the fh[2] entry.
698 * - then follow the ".." file finding the next step up.
699 *
700 * This way we build a path to the root of the tree. If this works, we
701 * lookup the path and so get this inode into the cache. Finally try
702 * the fat_iget lookup again. If that fails, then we are totally out
703 * of luck. But all that is for another day
704 */
705 result = d_obtain_alias(inode);
706 if (!IS_ERR(result))
707 result->d_op = sb->s_root->d_op;
708 return result;
709 }
710
711 static int
712 fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable)
713 {
714 int len = *lenp;
715 struct inode *inode = de->d_inode;
716 u32 ipos_h, ipos_m, ipos_l;
717
718 if (len < 5)
719 return 255; /* no room */
720
721 ipos_h = MSDOS_I(inode)->i_pos >> 8;
722 ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24;
723 ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28;
724 *lenp = 5;
725 fh[0] = inode->i_ino;
726 fh[1] = inode->i_generation;
727 fh[2] = ipos_h;
728 fh[3] = ipos_m | MSDOS_I(inode)->i_logstart;
729 spin_lock(&de->d_lock);
730 fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart;
731 spin_unlock(&de->d_lock);
732 return 3;
733 }
734
735 static struct dentry *fat_get_parent(struct dentry *child)
736 {
737 struct super_block *sb = child->d_sb;
738 struct buffer_head *bh;
739 struct msdos_dir_entry *de;
740 loff_t i_pos;
741 struct dentry *parent;
742 struct inode *inode;
743 int err;
744
745 lock_super(sb);
746
747 err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos);
748 if (err) {
749 parent = ERR_PTR(err);
750 goto out;
751 }
752 inode = fat_build_inode(sb, de, i_pos);
753 brelse(bh);
754
755 parent = d_obtain_alias(inode);
756 if (!IS_ERR(parent))
757 parent->d_op = sb->s_root->d_op;
758 out:
759 unlock_super(sb);
760
761 return parent;
762 }
763
764 static const struct export_operations fat_export_ops = {
765 .encode_fh = fat_encode_fh,
766 .fh_to_dentry = fat_fh_to_dentry,
767 .get_parent = fat_get_parent,
768 };
769
770 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt)
771 {
772 struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb);
773 struct fat_mount_options *opts = &sbi->options;
774 int isvfat = opts->isvfat;
775
776 if (opts->fs_uid != 0)
777 seq_printf(m, ",uid=%u", opts->fs_uid);
778 if (opts->fs_gid != 0)
779 seq_printf(m, ",gid=%u", opts->fs_gid);
780 seq_printf(m, ",fmask=%04o", opts->fs_fmask);
781 seq_printf(m, ",dmask=%04o", opts->fs_dmask);
782 if (opts->allow_utime)
783 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
784 if (sbi->nls_disk)
785 seq_printf(m, ",codepage=%s", sbi->nls_disk->charset);
786 if (isvfat) {
787 if (sbi->nls_io)
788 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
789
790 switch (opts->shortname) {
791 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
792 seq_puts(m, ",shortname=win95");
793 break;
794 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
795 seq_puts(m, ",shortname=winnt");
796 break;
797 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
798 seq_puts(m, ",shortname=mixed");
799 break;
800 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
801 /* seq_puts(m, ",shortname=lower"); */
802 break;
803 default:
804 seq_puts(m, ",shortname=unknown");
805 break;
806 }
807 }
808 if (opts->name_check != 'n')
809 seq_printf(m, ",check=%c", opts->name_check);
810 if (opts->usefree)
811 seq_puts(m, ",usefree");
812 if (opts->quiet)
813 seq_puts(m, ",quiet");
814 if (opts->showexec)
815 seq_puts(m, ",showexec");
816 if (opts->sys_immutable)
817 seq_puts(m, ",sys_immutable");
818 if (!isvfat) {
819 if (opts->dotsOK)
820 seq_puts(m, ",dotsOK=yes");
821 if (opts->nocase)
822 seq_puts(m, ",nocase");
823 } else {
824 if (opts->utf8)
825 seq_puts(m, ",utf8");
826 if (opts->unicode_xlate)
827 seq_puts(m, ",uni_xlate");
828 if (!opts->numtail)
829 seq_puts(m, ",nonumtail");
830 if (opts->rodir)
831 seq_puts(m, ",rodir");
832 }
833 if (opts->flush)
834 seq_puts(m, ",flush");
835 if (opts->tz_utc)
836 seq_puts(m, ",tz=UTC");
837
838 return 0;
839 }
840
841 enum {
842 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
843 Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
844 Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
845 Opt_immutable, Opt_dots, Opt_nodots,
846 Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
847 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
848 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
849 Opt_obsolate, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err,
850 };
851
852 static const match_table_t fat_tokens = {
853 {Opt_check_r, "check=relaxed"},
854 {Opt_check_s, "check=strict"},
855 {Opt_check_n, "check=normal"},
856 {Opt_check_r, "check=r"},
857 {Opt_check_s, "check=s"},
858 {Opt_check_n, "check=n"},
859 {Opt_uid, "uid=%u"},
860 {Opt_gid, "gid=%u"},
861 {Opt_umask, "umask=%o"},
862 {Opt_dmask, "dmask=%o"},
863 {Opt_fmask, "fmask=%o"},
864 {Opt_allow_utime, "allow_utime=%o"},
865 {Opt_codepage, "codepage=%u"},
866 {Opt_usefree, "usefree"},
867 {Opt_nocase, "nocase"},
868 {Opt_quiet, "quiet"},
869 {Opt_showexec, "showexec"},
870 {Opt_debug, "debug"},
871 {Opt_immutable, "sys_immutable"},
872 {Opt_obsolate, "conv=binary"},
873 {Opt_obsolate, "conv=text"},
874 {Opt_obsolate, "conv=auto"},
875 {Opt_obsolate, "conv=b"},
876 {Opt_obsolate, "conv=t"},
877 {Opt_obsolate, "conv=a"},
878 {Opt_obsolate, "fat=%u"},
879 {Opt_obsolate, "blocksize=%u"},
880 {Opt_obsolate, "cvf_format=%20s"},
881 {Opt_obsolate, "cvf_options=%100s"},
882 {Opt_obsolate, "posix"},
883 {Opt_flush, "flush"},
884 {Opt_tz_utc, "tz=UTC"},
885 {Opt_err, NULL},
886 };
887 static const match_table_t msdos_tokens = {
888 {Opt_nodots, "nodots"},
889 {Opt_nodots, "dotsOK=no"},
890 {Opt_dots, "dots"},
891 {Opt_dots, "dotsOK=yes"},
892 {Opt_err, NULL}
893 };
894 static const match_table_t vfat_tokens = {
895 {Opt_charset, "iocharset=%s"},
896 {Opt_shortname_lower, "shortname=lower"},
897 {Opt_shortname_win95, "shortname=win95"},
898 {Opt_shortname_winnt, "shortname=winnt"},
899 {Opt_shortname_mixed, "shortname=mixed"},
900 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */
901 {Opt_utf8_no, "utf8=no"},
902 {Opt_utf8_no, "utf8=false"},
903 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */
904 {Opt_utf8_yes, "utf8=yes"},
905 {Opt_utf8_yes, "utf8=true"},
906 {Opt_utf8_yes, "utf8"},
907 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */
908 {Opt_uni_xl_no, "uni_xlate=no"},
909 {Opt_uni_xl_no, "uni_xlate=false"},
910 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */
911 {Opt_uni_xl_yes, "uni_xlate=yes"},
912 {Opt_uni_xl_yes, "uni_xlate=true"},
913 {Opt_uni_xl_yes, "uni_xlate"},
914 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */
915 {Opt_nonumtail_no, "nonumtail=no"},
916 {Opt_nonumtail_no, "nonumtail=false"},
917 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */
918 {Opt_nonumtail_yes, "nonumtail=yes"},
919 {Opt_nonumtail_yes, "nonumtail=true"},
920 {Opt_nonumtail_yes, "nonumtail"},
921 {Opt_rodir, "rodir"},
922 {Opt_err, NULL}
923 };
924
925 static int parse_options(char *options, int is_vfat, int silent, int *debug,
926 struct fat_mount_options *opts)
927 {
928 char *p;
929 substring_t args[MAX_OPT_ARGS];
930 int option;
931 char *iocharset;
932
933 opts->isvfat = is_vfat;
934
935 opts->fs_uid = current_uid();
936 opts->fs_gid = current_gid();
937 opts->fs_fmask = current_umask();
938 opts->allow_utime = -1;
939 opts->codepage = fat_default_codepage;
940 opts->iocharset = fat_default_iocharset;
941 if (is_vfat) {
942 opts->shortname = VFAT_SFN_DISPLAY_LOWER|VFAT_SFN_CREATE_WIN95;
943 opts->rodir = 0;
944 } else {
945 opts->shortname = 0;
946 opts->rodir = 1;
947 }
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->usefree = opts->nocase = 0;
953 opts->tz_utc = 0;
954 *debug = 0;
955
956 if (!options)
957 goto out;
958
959 while ((p = strsep(&options, ",")) != NULL) {
960 int token;
961 if (!*p)
962 continue;
963
964 token = match_token(p, fat_tokens, args);
965 if (token == Opt_err) {
966 if (is_vfat)
967 token = match_token(p, vfat_tokens, args);
968 else
969 token = match_token(p, msdos_tokens, args);
970 }
971 switch (token) {
972 case Opt_check_s:
973 opts->name_check = 's';
974 break;
975 case Opt_check_r:
976 opts->name_check = 'r';
977 break;
978 case Opt_check_n:
979 opts->name_check = 'n';
980 break;
981 case Opt_usefree:
982 opts->usefree = 1;
983 break;
984 case Opt_nocase:
985 if (!is_vfat)
986 opts->nocase = 1;
987 else {
988 /* for backward compatibility */
989 opts->shortname = VFAT_SFN_DISPLAY_WIN95
990 | VFAT_SFN_CREATE_WIN95;
991 }
992 break;
993 case Opt_quiet:
994 opts->quiet = 1;
995 break;
996 case Opt_showexec:
997 opts->showexec = 1;
998 break;
999 case Opt_debug:
1000 *debug = 1;
1001 break;
1002 case Opt_immutable:
1003 opts->sys_immutable = 1;
1004 break;
1005 case Opt_uid:
1006 if (match_int(&args[0], &option))
1007 return 0;
1008 opts->fs_uid = option;
1009 break;
1010 case Opt_gid:
1011 if (match_int(&args[0], &option))
1012 return 0;
1013 opts->fs_gid = option;
1014 break;
1015 case Opt_umask:
1016 if (match_octal(&args[0], &option))
1017 return 0;
1018 opts->fs_fmask = opts->fs_dmask = option;
1019 break;
1020 case Opt_dmask:
1021 if (match_octal(&args[0], &option))
1022 return 0;
1023 opts->fs_dmask = option;
1024 break;
1025 case Opt_fmask:
1026 if (match_octal(&args[0], &option))
1027 return 0;
1028 opts->fs_fmask = option;
1029 break;
1030 case Opt_allow_utime:
1031 if (match_octal(&args[0], &option))
1032 return 0;
1033 opts->allow_utime = option & (S_IWGRP | S_IWOTH);
1034 break;
1035 case Opt_codepage:
1036 if (match_int(&args[0], &option))
1037 return 0;
1038 opts->codepage = option;
1039 break;
1040 case Opt_flush:
1041 opts->flush = 1;
1042 break;
1043 case Opt_tz_utc:
1044 opts->tz_utc = 1;
1045 break;
1046
1047 /* msdos specific */
1048 case Opt_dots:
1049 opts->dotsOK = 1;
1050 break;
1051 case Opt_nodots:
1052 opts->dotsOK = 0;
1053 break;
1054
1055 /* vfat specific */
1056 case Opt_charset:
1057 if (opts->iocharset != fat_default_iocharset)
1058 kfree(opts->iocharset);
1059 iocharset = match_strdup(&args[0]);
1060 if (!iocharset)
1061 return -ENOMEM;
1062 opts->iocharset = iocharset;
1063 break;
1064 case Opt_shortname_lower:
1065 opts->shortname = VFAT_SFN_DISPLAY_LOWER
1066 | VFAT_SFN_CREATE_WIN95;
1067 break;
1068 case Opt_shortname_win95:
1069 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1070 | VFAT_SFN_CREATE_WIN95;
1071 break;
1072 case Opt_shortname_winnt:
1073 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1074 | VFAT_SFN_CREATE_WINNT;
1075 break;
1076 case Opt_shortname_mixed:
1077 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1078 | VFAT_SFN_CREATE_WIN95;
1079 break;
1080 case Opt_utf8_no: /* 0 or no or false */
1081 opts->utf8 = 0;
1082 break;
1083 case Opt_utf8_yes: /* empty or 1 or yes or true */
1084 opts->utf8 = 1;
1085 break;
1086 case Opt_uni_xl_no: /* 0 or no or false */
1087 opts->unicode_xlate = 0;
1088 break;
1089 case Opt_uni_xl_yes: /* empty or 1 or yes or true */
1090 opts->unicode_xlate = 1;
1091 break;
1092 case Opt_nonumtail_no: /* 0 or no or false */
1093 opts->numtail = 1; /* negated option */
1094 break;
1095 case Opt_nonumtail_yes: /* empty or 1 or yes or true */
1096 opts->numtail = 0; /* negated option */
1097 break;
1098 case Opt_rodir:
1099 opts->rodir = 1;
1100 break;
1101
1102 /* obsolete mount options */
1103 case Opt_obsolate:
1104 printk(KERN_INFO "FAT: \"%s\" option is obsolete, "
1105 "not supported now\n", p);
1106 break;
1107 /* unknown option */
1108 default:
1109 if (!silent) {
1110 printk(KERN_ERR
1111 "FAT: Unrecognized mount option \"%s\" "
1112 "or missing value\n", p);
1113 }
1114 return -EINVAL;
1115 }
1116 }
1117
1118 out:
1119 /* UTF-8 doesn't provide FAT semantics */
1120 if (!strcmp(opts->iocharset, "utf8")) {
1121 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset"
1122 " for FAT filesystems, filesystem will be "
1123 "case sensitive!\n");
1124 }
1125
1126 /* If user doesn't specify allow_utime, it's initialized from dmask. */
1127 if (opts->allow_utime == (unsigned short)-1)
1128 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1129 if (opts->unicode_xlate)
1130 opts->utf8 = 0;
1131
1132 return 0;
1133 }
1134
1135 static int fat_read_root(struct inode *inode)
1136 {
1137 struct super_block *sb = inode->i_sb;
1138 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1139 int error;
1140
1141 MSDOS_I(inode)->i_pos = 0;
1142 inode->i_uid = sbi->options.fs_uid;
1143 inode->i_gid = sbi->options.fs_gid;
1144 inode->i_version++;
1145 inode->i_generation = 0;
1146 inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
1147 inode->i_op = sbi->dir_ops;
1148 inode->i_fop = &fat_dir_operations;
1149 if (sbi->fat_bits == 32) {
1150 MSDOS_I(inode)->i_start = sbi->root_cluster;
1151 error = fat_calc_dir_size(inode);
1152 if (error < 0)
1153 return error;
1154 } else {
1155 MSDOS_I(inode)->i_start = 0;
1156 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1157 }
1158 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1159 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1160 MSDOS_I(inode)->i_logstart = 0;
1161 MSDOS_I(inode)->mmu_private = inode->i_size;
1162
1163 fat_save_attrs(inode, ATTR_DIR);
1164 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1165 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1166 inode->i_nlink = fat_subdirs(inode)+2;
1167
1168 return 0;
1169 }
1170
1171 /*
1172 * Read the super block of an MS-DOS FS.
1173 */
1174 int fat_fill_super(struct super_block *sb, void *data, int silent,
1175 const struct inode_operations *fs_dir_inode_ops, int isvfat)
1176 {
1177 struct inode *root_inode = NULL;
1178 struct buffer_head *bh;
1179 struct fat_boot_sector *b;
1180 struct msdos_sb_info *sbi;
1181 u16 logical_sector_size;
1182 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1183 int debug;
1184 unsigned int media;
1185 long error;
1186 char buf[50];
1187
1188 /*
1189 * GFP_KERNEL is ok here, because while we do hold the
1190 * supeblock lock, memory pressure can't call back into
1191 * the filesystem, since we're only just about to mount
1192 * it and have no inodes etc active!
1193 */
1194 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1195 if (!sbi)
1196 return -ENOMEM;
1197 sb->s_fs_info = sbi;
1198
1199 sb->s_flags |= MS_NODIRATIME;
1200 sb->s_magic = MSDOS_SUPER_MAGIC;
1201 sb->s_op = &fat_sops;
1202 sb->s_export_op = &fat_export_ops;
1203 sbi->dir_ops = fs_dir_inode_ops;
1204
1205 error = parse_options(data, isvfat, silent, &debug, &sbi->options);
1206 if (error)
1207 goto out_fail;
1208
1209 error = -EIO;
1210 sb_min_blocksize(sb, 512);
1211 bh = sb_bread(sb, 0);
1212 if (bh == NULL) {
1213 printk(KERN_ERR "FAT: unable to read boot sector\n");
1214 goto out_fail;
1215 }
1216
1217 b = (struct fat_boot_sector *) bh->b_data;
1218 if (!b->reserved) {
1219 if (!silent)
1220 printk(KERN_ERR "FAT: bogus number of reserved sectors\n");
1221 brelse(bh);
1222 goto out_invalid;
1223 }
1224 if (!b->fats) {
1225 if (!silent)
1226 printk(KERN_ERR "FAT: bogus number of FAT structure\n");
1227 brelse(bh);
1228 goto out_invalid;
1229 }
1230
1231 /*
1232 * Earlier we checked here that b->secs_track and b->head are nonzero,
1233 * but it turns out valid FAT filesystems can have zero there.
1234 */
1235
1236 media = b->media;
1237 if (!fat_valid_media(media)) {
1238 if (!silent)
1239 printk(KERN_ERR "FAT: invalid media value (0x%02x)\n",
1240 media);
1241 brelse(bh);
1242 goto out_invalid;
1243 }
1244 logical_sector_size = get_unaligned_le16(&b->sector_size);
1245 if (!is_power_of_2(logical_sector_size)
1246 || (logical_sector_size < 512)
1247 || (logical_sector_size > 4096)) {
1248 if (!silent)
1249 printk(KERN_ERR "FAT: bogus logical sector size %u\n",
1250 logical_sector_size);
1251 brelse(bh);
1252 goto out_invalid;
1253 }
1254 sbi->sec_per_clus = b->sec_per_clus;
1255 if (!is_power_of_2(sbi->sec_per_clus)) {
1256 if (!silent)
1257 printk(KERN_ERR "FAT: bogus sectors per cluster %u\n",
1258 sbi->sec_per_clus);
1259 brelse(bh);
1260 goto out_invalid;
1261 }
1262
1263 if (logical_sector_size < sb->s_blocksize) {
1264 printk(KERN_ERR "FAT: logical sector size too small for device"
1265 " (logical sector size = %u)\n", logical_sector_size);
1266 brelse(bh);
1267 goto out_fail;
1268 }
1269 if (logical_sector_size > sb->s_blocksize) {
1270 brelse(bh);
1271
1272 if (!sb_set_blocksize(sb, logical_sector_size)) {
1273 printk(KERN_ERR "FAT: unable to set blocksize %u\n",
1274 logical_sector_size);
1275 goto out_fail;
1276 }
1277 bh = sb_bread(sb, 0);
1278 if (bh == NULL) {
1279 printk(KERN_ERR "FAT: unable to read boot sector"
1280 " (logical sector size = %lu)\n",
1281 sb->s_blocksize);
1282 goto out_fail;
1283 }
1284 b = (struct fat_boot_sector *) bh->b_data;
1285 }
1286
1287 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1288 sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1289 sbi->fats = b->fats;
1290 sbi->fat_bits = 0; /* Don't know yet */
1291 sbi->fat_start = le16_to_cpu(b->reserved);
1292 sbi->fat_length = le16_to_cpu(b->fat_length);
1293 sbi->root_cluster = 0;
1294 sbi->free_clusters = -1; /* Don't know yet */
1295 sbi->free_clus_valid = 0;
1296 sbi->prev_free = FAT_START_ENT;
1297
1298 if (!sbi->fat_length && b->fat32_length) {
1299 struct fat_boot_fsinfo *fsinfo;
1300 struct buffer_head *fsinfo_bh;
1301
1302 /* Must be FAT32 */
1303 sbi->fat_bits = 32;
1304 sbi->fat_length = le32_to_cpu(b->fat32_length);
1305 sbi->root_cluster = le32_to_cpu(b->root_cluster);
1306
1307 sb->s_maxbytes = 0xffffffff;
1308
1309 /* MC - if info_sector is 0, don't multiply by 0 */
1310 sbi->fsinfo_sector = le16_to_cpu(b->info_sector);
1311 if (sbi->fsinfo_sector == 0)
1312 sbi->fsinfo_sector = 1;
1313
1314 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1315 if (fsinfo_bh == NULL) {
1316 printk(KERN_ERR "FAT: bread failed, FSINFO block"
1317 " (sector = %lu)\n", sbi->fsinfo_sector);
1318 brelse(bh);
1319 goto out_fail;
1320 }
1321
1322 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1323 if (!IS_FSINFO(fsinfo)) {
1324 printk(KERN_WARNING "FAT: Invalid FSINFO signature: "
1325 "0x%08x, 0x%08x (sector = %lu)\n",
1326 le32_to_cpu(fsinfo->signature1),
1327 le32_to_cpu(fsinfo->signature2),
1328 sbi->fsinfo_sector);
1329 } else {
1330 if (sbi->options.usefree)
1331 sbi->free_clus_valid = 1;
1332 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1333 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1334 }
1335
1336 brelse(fsinfo_bh);
1337 }
1338
1339 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1340 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1341
1342 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1343 sbi->dir_entries = get_unaligned_le16(&b->dir_entries);
1344 if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1345 if (!silent)
1346 printk(KERN_ERR "FAT: bogus directroy-entries per block"
1347 " (%u)\n", sbi->dir_entries);
1348 brelse(bh);
1349 goto out_invalid;
1350 }
1351
1352 rootdir_sectors = sbi->dir_entries
1353 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1354 sbi->data_start = sbi->dir_start + rootdir_sectors;
1355 total_sectors = get_unaligned_le16(&b->sectors);
1356 if (total_sectors == 0)
1357 total_sectors = le32_to_cpu(b->total_sect);
1358
1359 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1360
1361 if (sbi->fat_bits != 32)
1362 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1363
1364 /* check that FAT table does not overflow */
1365 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1366 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1367 if (total_clusters > MAX_FAT(sb)) {
1368 if (!silent)
1369 printk(KERN_ERR "FAT: count of clusters too big (%u)\n",
1370 total_clusters);
1371 brelse(bh);
1372 goto out_invalid;
1373 }
1374
1375 sbi->max_cluster = total_clusters + FAT_START_ENT;
1376 /* check the free_clusters, it's not necessarily correct */
1377 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1378 sbi->free_clusters = -1;
1379 /* check the prev_free, it's not necessarily correct */
1380 sbi->prev_free %= sbi->max_cluster;
1381 if (sbi->prev_free < FAT_START_ENT)
1382 sbi->prev_free = FAT_START_ENT;
1383
1384 brelse(bh);
1385
1386 /* set up enough so that it can read an inode */
1387 fat_hash_init(sb);
1388 fat_ent_access_init(sb);
1389
1390 /*
1391 * The low byte of FAT's first entry must have same value with
1392 * media-field. But in real world, too many devices is
1393 * writing wrong value. So, removed that validity check.
1394 *
1395 * if (FAT_FIRST_ENT(sb, media) != first)
1396 */
1397
1398 error = -EINVAL;
1399 sprintf(buf, "cp%d", sbi->options.codepage);
1400 sbi->nls_disk = load_nls(buf);
1401 if (!sbi->nls_disk) {
1402 printk(KERN_ERR "FAT: codepage %s not found\n", buf);
1403 goto out_fail;
1404 }
1405
1406 /* FIXME: utf8 is using iocharset for upper/lower conversion */
1407 if (sbi->options.isvfat) {
1408 sbi->nls_io = load_nls(sbi->options.iocharset);
1409 if (!sbi->nls_io) {
1410 printk(KERN_ERR "FAT: IO charset %s not found\n",
1411 sbi->options.iocharset);
1412 goto out_fail;
1413 }
1414 }
1415
1416 error = -ENOMEM;
1417 root_inode = new_inode(sb);
1418 if (!root_inode)
1419 goto out_fail;
1420 root_inode->i_ino = MSDOS_ROOT_INO;
1421 root_inode->i_version = 1;
1422 error = fat_read_root(root_inode);
1423 if (error < 0)
1424 goto out_fail;
1425 error = -ENOMEM;
1426 insert_inode_hash(root_inode);
1427 sb->s_root = d_alloc_root(root_inode);
1428 if (!sb->s_root) {
1429 printk(KERN_ERR "FAT: get root inode failed\n");
1430 goto out_fail;
1431 }
1432
1433 return 0;
1434
1435 out_invalid:
1436 error = -EINVAL;
1437 if (!silent)
1438 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem"
1439 " on dev %s.\n", sb->s_id);
1440
1441 out_fail:
1442 if (root_inode)
1443 iput(root_inode);
1444 if (sbi->nls_io)
1445 unload_nls(sbi->nls_io);
1446 if (sbi->nls_disk)
1447 unload_nls(sbi->nls_disk);
1448 if (sbi->options.iocharset != fat_default_iocharset)
1449 kfree(sbi->options.iocharset);
1450 sb->s_fs_info = NULL;
1451 kfree(sbi);
1452 return error;
1453 }
1454
1455 EXPORT_SYMBOL_GPL(fat_fill_super);
1456
1457 /*
1458 * helper function for fat_flush_inodes. This writes both the inode
1459 * and the file data blocks, waiting for in flight data blocks before
1460 * the start of the call. It does not wait for any io started
1461 * during the call
1462 */
1463 static int writeback_inode(struct inode *inode)
1464 {
1465
1466 int ret;
1467 struct address_space *mapping = inode->i_mapping;
1468 struct writeback_control wbc = {
1469 .sync_mode = WB_SYNC_NONE,
1470 .nr_to_write = 0,
1471 };
1472 /* if we used WB_SYNC_ALL, sync_inode waits for the io for the
1473 * inode to finish. So WB_SYNC_NONE is sent down to sync_inode
1474 * and filemap_fdatawrite is used for the data blocks
1475 */
1476 ret = sync_inode(inode, &wbc);
1477 if (!ret)
1478 ret = filemap_fdatawrite(mapping);
1479 return ret;
1480 }
1481
1482 /*
1483 * write data and metadata corresponding to i1 and i2. The io is
1484 * started but we do not wait for any of it to finish.
1485 *
1486 * filemap_flush is used for the block device, so if there is a dirty
1487 * page for a block already in flight, we will not wait and start the
1488 * io over again
1489 */
1490 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1491 {
1492 int ret = 0;
1493 if (!MSDOS_SB(sb)->options.flush)
1494 return 0;
1495 if (i1)
1496 ret = writeback_inode(i1);
1497 if (!ret && i2)
1498 ret = writeback_inode(i2);
1499 if (!ret) {
1500 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
1501 ret = filemap_flush(mapping);
1502 }
1503 return ret;
1504 }
1505 EXPORT_SYMBOL_GPL(fat_flush_inodes);
1506
1507 static int __init init_fat_fs(void)
1508 {
1509 int err;
1510
1511 err = fat_cache_init();
1512 if (err)
1513 return err;
1514
1515 err = fat_init_inodecache();
1516 if (err)
1517 goto failed;
1518
1519 return 0;
1520
1521 failed:
1522 fat_cache_destroy();
1523 return err;
1524 }
1525
1526 static void __exit exit_fat_fs(void)
1527 {
1528 fat_cache_destroy();
1529 fat_destroy_inodecache();
1530 }
1531
1532 module_init(init_fat_fs)
1533 module_exit(exit_fat_fs)
1534
1535 MODULE_LICENSE("GPL");
Linus' kernel tree