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remove ->write_super call in generic_shutdown_super
[GitHub/mt8127/android_kernel_alcatel_ttab.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/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 (sb->s_dirt)
455 fat_write_super(sb);
456
457 if (sbi->nls_disk) {
458 unload_nls(sbi->nls_disk);
459 sbi->nls_disk = NULL;
460 sbi->options.codepage = fat_default_codepage;
461 }
462 if (sbi->nls_io) {
463 unload_nls(sbi->nls_io);
464 sbi->nls_io = NULL;
465 }
466 if (sbi->options.iocharset != fat_default_iocharset) {
467 kfree(sbi->options.iocharset);
468 sbi->options.iocharset = fat_default_iocharset;
469 }
470
471 sb->s_fs_info = NULL;
472 kfree(sbi);
473 }
474
475 static struct kmem_cache *fat_inode_cachep;
476
477 static struct inode *fat_alloc_inode(struct super_block *sb)
478 {
479 struct msdos_inode_info *ei;
480 ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
481 if (!ei)
482 return NULL;
483 return &ei->vfs_inode;
484 }
485
486 static void fat_destroy_inode(struct inode *inode)
487 {
488 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
489 }
490
491 static void init_once(void *foo)
492 {
493 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
494
495 spin_lock_init(&ei->cache_lru_lock);
496 ei->nr_caches = 0;
497 ei->cache_valid_id = FAT_CACHE_VALID + 1;
498 INIT_LIST_HEAD(&ei->cache_lru);
499 INIT_HLIST_NODE(&ei->i_fat_hash);
500 inode_init_once(&ei->vfs_inode);
501 }
502
503 static int __init fat_init_inodecache(void)
504 {
505 fat_inode_cachep = kmem_cache_create("fat_inode_cache",
506 sizeof(struct msdos_inode_info),
507 0, (SLAB_RECLAIM_ACCOUNT|
508 SLAB_MEM_SPREAD),
509 init_once);
510 if (fat_inode_cachep == NULL)
511 return -ENOMEM;
512 return 0;
513 }
514
515 static void __exit fat_destroy_inodecache(void)
516 {
517 kmem_cache_destroy(fat_inode_cachep);
518 }
519
520 static int fat_remount(struct super_block *sb, int *flags, char *data)
521 {
522 struct msdos_sb_info *sbi = MSDOS_SB(sb);
523 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME);
524 return 0;
525 }
526
527 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
528 {
529 struct super_block *sb = dentry->d_sb;
530 struct msdos_sb_info *sbi = MSDOS_SB(sb);
531 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
532
533 /* If the count of free cluster is still unknown, counts it here. */
534 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
535 int err = fat_count_free_clusters(dentry->d_sb);
536 if (err)
537 return err;
538 }
539
540 buf->f_type = dentry->d_sb->s_magic;
541 buf->f_bsize = sbi->cluster_size;
542 buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
543 buf->f_bfree = sbi->free_clusters;
544 buf->f_bavail = sbi->free_clusters;
545 buf->f_fsid.val[0] = (u32)id;
546 buf->f_fsid.val[1] = (u32)(id >> 32);
547 buf->f_namelen = sbi->options.isvfat ? 260 : 12;
548
549 return 0;
550 }
551
552 static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi,
553 struct inode *inode)
554 {
555 loff_t i_pos;
556 #if BITS_PER_LONG == 32
557 spin_lock(&sbi->inode_hash_lock);
558 #endif
559 i_pos = MSDOS_I(inode)->i_pos;
560 #if BITS_PER_LONG == 32
561 spin_unlock(&sbi->inode_hash_lock);
562 #endif
563 return i_pos;
564 }
565
566 static int fat_write_inode(struct inode *inode, int wait)
567 {
568 struct super_block *sb = inode->i_sb;
569 struct msdos_sb_info *sbi = MSDOS_SB(sb);
570 struct buffer_head *bh;
571 struct msdos_dir_entry *raw_entry;
572 loff_t i_pos;
573 int err;
574
575 if (inode->i_ino == MSDOS_ROOT_INO)
576 return 0;
577
578 retry:
579 i_pos = fat_i_pos_read(sbi, inode);
580 if (!i_pos)
581 return 0;
582
583 bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits);
584 if (!bh) {
585 printk(KERN_ERR "FAT: unable to read inode block "
586 "for updating (i_pos %lld)\n", i_pos);
587 return -EIO;
588 }
589 spin_lock(&sbi->inode_hash_lock);
590 if (i_pos != MSDOS_I(inode)->i_pos) {
591 spin_unlock(&sbi->inode_hash_lock);
592 brelse(bh);
593 goto retry;
594 }
595
596 raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
597 [i_pos & (sbi->dir_per_block - 1)];
598 if (S_ISDIR(inode->i_mode))
599 raw_entry->size = 0;
600 else
601 raw_entry->size = cpu_to_le32(inode->i_size);
602 raw_entry->attr = fat_make_attrs(inode);
603 raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart);
604 raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16);
605 fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
606 &raw_entry->date, NULL);
607 if (sbi->options.isvfat) {
608 __le16 atime;
609 fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime,
610 &raw_entry->cdate, &raw_entry->ctime_cs);
611 fat_time_unix2fat(sbi, &inode->i_atime, &atime,
612 &raw_entry->adate, NULL);
613 }
614 spin_unlock(&sbi->inode_hash_lock);
615 mark_buffer_dirty(bh);
616 err = 0;
617 if (wait)
618 err = sync_dirty_buffer(bh);
619 brelse(bh);
620 return err;
621 }
622
623 int fat_sync_inode(struct inode *inode)
624 {
625 return fat_write_inode(inode, 1);
626 }
627
628 EXPORT_SYMBOL_GPL(fat_sync_inode);
629
630 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt);
631 static const struct super_operations fat_sops = {
632 .alloc_inode = fat_alloc_inode,
633 .destroy_inode = fat_destroy_inode,
634 .write_inode = fat_write_inode,
635 .delete_inode = fat_delete_inode,
636 .put_super = fat_put_super,
637 .write_super = fat_write_super,
638 .statfs = fat_statfs,
639 .clear_inode = fat_clear_inode,
640 .remount_fs = fat_remount,
641
642 .show_options = fat_show_options,
643 };
644
645 /*
646 * a FAT file handle with fhtype 3 is
647 * 0/ i_ino - for fast, reliable lookup if still in the cache
648 * 1/ i_generation - to see if i_ino is still valid
649 * bit 0 == 0 iff directory
650 * 2/ i_pos(8-39) - if ino has changed, but still in cache
651 * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos
652 * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc
653 *
654 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum
655 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits
656 * of i_logstart is used to store the directory entry offset.
657 */
658
659 static struct dentry *fat_fh_to_dentry(struct super_block *sb,
660 struct fid *fid, int fh_len, int fh_type)
661 {
662 struct inode *inode = NULL;
663 struct dentry *result;
664 u32 *fh = fid->raw;
665
666 if (fh_len < 5 || fh_type != 3)
667 return NULL;
668
669 inode = ilookup(sb, fh[0]);
670 if (!inode || inode->i_generation != fh[1]) {
671 if (inode)
672 iput(inode);
673 inode = NULL;
674 }
675 if (!inode) {
676 loff_t i_pos;
677 int i_logstart = fh[3] & 0x0fffffff;
678
679 i_pos = (loff_t)fh[2] << 8;
680 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28);
681
682 /* try 2 - see if i_pos is in F-d-c
683 * require i_logstart to be the same
684 * Will fail if you truncate and then re-write
685 */
686
687 inode = fat_iget(sb, i_pos);
688 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) {
689 iput(inode);
690 inode = NULL;
691 }
692 }
693
694 /*
695 * For now, do nothing if the inode is not found.
696 *
697 * What we could do is:
698 *
699 * - follow the file starting at fh[4], and record the ".." entry,
700 * and the name of the fh[2] entry.
701 * - then follow the ".." file finding the next step up.
702 *
703 * This way we build a path to the root of the tree. If this works, we
704 * lookup the path and so get this inode into the cache. Finally try
705 * the fat_iget lookup again. If that fails, then we are totally out
706 * of luck. But all that is for another day
707 */
708 result = d_obtain_alias(inode);
709 if (!IS_ERR(result))
710 result->d_op = sb->s_root->d_op;
711 return result;
712 }
713
714 static int
715 fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable)
716 {
717 int len = *lenp;
718 struct inode *inode = de->d_inode;
719 u32 ipos_h, ipos_m, ipos_l;
720
721 if (len < 5)
722 return 255; /* no room */
723
724 ipos_h = MSDOS_I(inode)->i_pos >> 8;
725 ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24;
726 ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28;
727 *lenp = 5;
728 fh[0] = inode->i_ino;
729 fh[1] = inode->i_generation;
730 fh[2] = ipos_h;
731 fh[3] = ipos_m | MSDOS_I(inode)->i_logstart;
732 spin_lock(&de->d_lock);
733 fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart;
734 spin_unlock(&de->d_lock);
735 return 3;
736 }
737
738 static struct dentry *fat_get_parent(struct dentry *child)
739 {
740 struct super_block *sb = child->d_sb;
741 struct buffer_head *bh;
742 struct msdos_dir_entry *de;
743 loff_t i_pos;
744 struct dentry *parent;
745 struct inode *inode;
746 int err;
747
748 lock_super(sb);
749
750 err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos);
751 if (err) {
752 parent = ERR_PTR(err);
753 goto out;
754 }
755 inode = fat_build_inode(sb, de, i_pos);
756 brelse(bh);
757
758 parent = d_obtain_alias(inode);
759 if (!IS_ERR(parent))
760 parent->d_op = sb->s_root->d_op;
761 out:
762 unlock_super(sb);
763
764 return parent;
765 }
766
767 static const struct export_operations fat_export_ops = {
768 .encode_fh = fat_encode_fh,
769 .fh_to_dentry = fat_fh_to_dentry,
770 .get_parent = fat_get_parent,
771 };
772
773 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt)
774 {
775 struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb);
776 struct fat_mount_options *opts = &sbi->options;
777 int isvfat = opts->isvfat;
778
779 if (opts->fs_uid != 0)
780 seq_printf(m, ",uid=%u", opts->fs_uid);
781 if (opts->fs_gid != 0)
782 seq_printf(m, ",gid=%u", opts->fs_gid);
783 seq_printf(m, ",fmask=%04o", opts->fs_fmask);
784 seq_printf(m, ",dmask=%04o", opts->fs_dmask);
785 if (opts->allow_utime)
786 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
787 if (sbi->nls_disk)
788 seq_printf(m, ",codepage=%s", sbi->nls_disk->charset);
789 if (isvfat) {
790 if (sbi->nls_io)
791 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
792
793 switch (opts->shortname) {
794 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
795 seq_puts(m, ",shortname=win95");
796 break;
797 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
798 seq_puts(m, ",shortname=winnt");
799 break;
800 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
801 seq_puts(m, ",shortname=mixed");
802 break;
803 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
804 /* seq_puts(m, ",shortname=lower"); */
805 break;
806 default:
807 seq_puts(m, ",shortname=unknown");
808 break;
809 }
810 }
811 if (opts->name_check != 'n')
812 seq_printf(m, ",check=%c", opts->name_check);
813 if (opts->usefree)
814 seq_puts(m, ",usefree");
815 if (opts->quiet)
816 seq_puts(m, ",quiet");
817 if (opts->showexec)
818 seq_puts(m, ",showexec");
819 if (opts->sys_immutable)
820 seq_puts(m, ",sys_immutable");
821 if (!isvfat) {
822 if (opts->dotsOK)
823 seq_puts(m, ",dotsOK=yes");
824 if (opts->nocase)
825 seq_puts(m, ",nocase");
826 } else {
827 if (opts->utf8)
828 seq_puts(m, ",utf8");
829 if (opts->unicode_xlate)
830 seq_puts(m, ",uni_xlate");
831 if (!opts->numtail)
832 seq_puts(m, ",nonumtail");
833 if (opts->rodir)
834 seq_puts(m, ",rodir");
835 }
836 if (opts->flush)
837 seq_puts(m, ",flush");
838 if (opts->tz_utc)
839 seq_puts(m, ",tz=UTC");
840
841 return 0;
842 }
843
844 enum {
845 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
846 Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
847 Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
848 Opt_immutable, Opt_dots, Opt_nodots,
849 Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
850 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
851 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
852 Opt_obsolate, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err,
853 };
854
855 static const match_table_t fat_tokens = {
856 {Opt_check_r, "check=relaxed"},
857 {Opt_check_s, "check=strict"},
858 {Opt_check_n, "check=normal"},
859 {Opt_check_r, "check=r"},
860 {Opt_check_s, "check=s"},
861 {Opt_check_n, "check=n"},
862 {Opt_uid, "uid=%u"},
863 {Opt_gid, "gid=%u"},
864 {Opt_umask, "umask=%o"},
865 {Opt_dmask, "dmask=%o"},
866 {Opt_fmask, "fmask=%o"},
867 {Opt_allow_utime, "allow_utime=%o"},
868 {Opt_codepage, "codepage=%u"},
869 {Opt_usefree, "usefree"},
870 {Opt_nocase, "nocase"},
871 {Opt_quiet, "quiet"},
872 {Opt_showexec, "showexec"},
873 {Opt_debug, "debug"},
874 {Opt_immutable, "sys_immutable"},
875 {Opt_obsolate, "conv=binary"},
876 {Opt_obsolate, "conv=text"},
877 {Opt_obsolate, "conv=auto"},
878 {Opt_obsolate, "conv=b"},
879 {Opt_obsolate, "conv=t"},
880 {Opt_obsolate, "conv=a"},
881 {Opt_obsolate, "fat=%u"},
882 {Opt_obsolate, "blocksize=%u"},
883 {Opt_obsolate, "cvf_format=%20s"},
884 {Opt_obsolate, "cvf_options=%100s"},
885 {Opt_obsolate, "posix"},
886 {Opt_flush, "flush"},
887 {Opt_tz_utc, "tz=UTC"},
888 {Opt_err, NULL},
889 };
890 static const 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 const 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_rodir, "rodir"},
925 {Opt_err, NULL}
926 };
927
928 static int parse_options(char *options, int is_vfat, int silent, int *debug,
929 struct fat_mount_options *opts)
930 {
931 char *p;
932 substring_t args[MAX_OPT_ARGS];
933 int option;
934 char *iocharset;
935
936 opts->isvfat = is_vfat;
937
938 opts->fs_uid = current_uid();
939 opts->fs_gid = current_gid();
940 opts->fs_fmask = current_umask();
941 opts->allow_utime = -1;
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 opts->rodir = 0;
947 } else {
948 opts->shortname = 0;
949 opts->rodir = 1;
950 }
951 opts->name_check = 'n';
952 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0;
953 opts->utf8 = opts->unicode_xlate = 0;
954 opts->numtail = 1;
955 opts->usefree = opts->nocase = 0;
956 opts->tz_utc = 0;
957 *debug = 0;
958
959 if (!options)
960 goto out;
961
962 while ((p = strsep(&options, ",")) != NULL) {
963 int token;
964 if (!*p)
965 continue;
966
967 token = match_token(p, fat_tokens, args);
968 if (token == Opt_err) {
969 if (is_vfat)
970 token = match_token(p, vfat_tokens, args);
971 else
972 token = match_token(p, msdos_tokens, args);
973 }
974 switch (token) {
975 case Opt_check_s:
976 opts->name_check = 's';
977 break;
978 case Opt_check_r:
979 opts->name_check = 'r';
980 break;
981 case Opt_check_n:
982 opts->name_check = 'n';
983 break;
984 case Opt_usefree:
985 opts->usefree = 1;
986 break;
987 case Opt_nocase:
988 if (!is_vfat)
989 opts->nocase = 1;
990 else {
991 /* for backward compatibility */
992 opts->shortname = VFAT_SFN_DISPLAY_WIN95
993 | VFAT_SFN_CREATE_WIN95;
994 }
995 break;
996 case Opt_quiet:
997 opts->quiet = 1;
998 break;
999 case Opt_showexec:
1000 opts->showexec = 1;
1001 break;
1002 case Opt_debug:
1003 *debug = 1;
1004 break;
1005 case Opt_immutable:
1006 opts->sys_immutable = 1;
1007 break;
1008 case Opt_uid:
1009 if (match_int(&args[0], &option))
1010 return 0;
1011 opts->fs_uid = option;
1012 break;
1013 case Opt_gid:
1014 if (match_int(&args[0], &option))
1015 return 0;
1016 opts->fs_gid = option;
1017 break;
1018 case Opt_umask:
1019 if (match_octal(&args[0], &option))
1020 return 0;
1021 opts->fs_fmask = opts->fs_dmask = option;
1022 break;
1023 case Opt_dmask:
1024 if (match_octal(&args[0], &option))
1025 return 0;
1026 opts->fs_dmask = option;
1027 break;
1028 case Opt_fmask:
1029 if (match_octal(&args[0], &option))
1030 return 0;
1031 opts->fs_fmask = option;
1032 break;
1033 case Opt_allow_utime:
1034 if (match_octal(&args[0], &option))
1035 return 0;
1036 opts->allow_utime = option & (S_IWGRP | S_IWOTH);
1037 break;
1038 case Opt_codepage:
1039 if (match_int(&args[0], &option))
1040 return 0;
1041 opts->codepage = option;
1042 break;
1043 case Opt_flush:
1044 opts->flush = 1;
1045 break;
1046 case Opt_tz_utc:
1047 opts->tz_utc = 1;
1048 break;
1049
1050 /* msdos specific */
1051 case Opt_dots:
1052 opts->dotsOK = 1;
1053 break;
1054 case Opt_nodots:
1055 opts->dotsOK = 0;
1056 break;
1057
1058 /* vfat specific */
1059 case Opt_charset:
1060 if (opts->iocharset != fat_default_iocharset)
1061 kfree(opts->iocharset);
1062 iocharset = match_strdup(&args[0]);
1063 if (!iocharset)
1064 return -ENOMEM;
1065 opts->iocharset = iocharset;
1066 break;
1067 case Opt_shortname_lower:
1068 opts->shortname = VFAT_SFN_DISPLAY_LOWER
1069 | VFAT_SFN_CREATE_WIN95;
1070 break;
1071 case Opt_shortname_win95:
1072 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1073 | VFAT_SFN_CREATE_WIN95;
1074 break;
1075 case Opt_shortname_winnt:
1076 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1077 | VFAT_SFN_CREATE_WINNT;
1078 break;
1079 case Opt_shortname_mixed:
1080 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1081 | VFAT_SFN_CREATE_WIN95;
1082 break;
1083 case Opt_utf8_no: /* 0 or no or false */
1084 opts->utf8 = 0;
1085 break;
1086 case Opt_utf8_yes: /* empty or 1 or yes or true */
1087 opts->utf8 = 1;
1088 break;
1089 case Opt_uni_xl_no: /* 0 or no or false */
1090 opts->unicode_xlate = 0;
1091 break;
1092 case Opt_uni_xl_yes: /* empty or 1 or yes or true */
1093 opts->unicode_xlate = 1;
1094 break;
1095 case Opt_nonumtail_no: /* 0 or no or false */
1096 opts->numtail = 1; /* negated option */
1097 break;
1098 case Opt_nonumtail_yes: /* empty or 1 or yes or true */
1099 opts->numtail = 0; /* negated option */
1100 break;
1101 case Opt_rodir:
1102 opts->rodir = 1;
1103 break;
1104
1105 /* obsolete mount options */
1106 case Opt_obsolate:
1107 printk(KERN_INFO "FAT: \"%s\" option is obsolete, "
1108 "not supported now\n", p);
1109 break;
1110 /* unknown option */
1111 default:
1112 if (!silent) {
1113 printk(KERN_ERR
1114 "FAT: Unrecognized mount option \"%s\" "
1115 "or missing value\n", p);
1116 }
1117 return -EINVAL;
1118 }
1119 }
1120
1121 out:
1122 /* UTF-8 doesn't provide FAT semantics */
1123 if (!strcmp(opts->iocharset, "utf8")) {
1124 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset"
1125 " for FAT filesystems, filesystem will be "
1126 "case sensitive!\n");
1127 }
1128
1129 /* If user doesn't specify allow_utime, it's initialized from dmask. */
1130 if (opts->allow_utime == (unsigned short)-1)
1131 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1132 if (opts->unicode_xlate)
1133 opts->utf8 = 0;
1134
1135 return 0;
1136 }
1137
1138 static int fat_read_root(struct inode *inode)
1139 {
1140 struct super_block *sb = inode->i_sb;
1141 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1142 int error;
1143
1144 MSDOS_I(inode)->i_pos = 0;
1145 inode->i_uid = sbi->options.fs_uid;
1146 inode->i_gid = sbi->options.fs_gid;
1147 inode->i_version++;
1148 inode->i_generation = 0;
1149 inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
1150 inode->i_op = sbi->dir_ops;
1151 inode->i_fop = &fat_dir_operations;
1152 if (sbi->fat_bits == 32) {
1153 MSDOS_I(inode)->i_start = sbi->root_cluster;
1154 error = fat_calc_dir_size(inode);
1155 if (error < 0)
1156 return error;
1157 } else {
1158 MSDOS_I(inode)->i_start = 0;
1159 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1160 }
1161 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1162 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1163 MSDOS_I(inode)->i_logstart = 0;
1164 MSDOS_I(inode)->mmu_private = inode->i_size;
1165
1166 fat_save_attrs(inode, ATTR_DIR);
1167 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1168 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1169 inode->i_nlink = fat_subdirs(inode)+2;
1170
1171 return 0;
1172 }
1173
1174 /*
1175 * Read the super block of an MS-DOS FS.
1176 */
1177 int fat_fill_super(struct super_block *sb, void *data, int silent,
1178 const struct inode_operations *fs_dir_inode_ops, int isvfat)
1179 {
1180 struct inode *root_inode = NULL;
1181 struct buffer_head *bh;
1182 struct fat_boot_sector *b;
1183 struct msdos_sb_info *sbi;
1184 u16 logical_sector_size;
1185 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1186 int debug;
1187 unsigned int media;
1188 long error;
1189 char buf[50];
1190
1191 /*
1192 * GFP_KERNEL is ok here, because while we do hold the
1193 * supeblock lock, memory pressure can't call back into
1194 * the filesystem, since we're only just about to mount
1195 * it and have no inodes etc active!
1196 */
1197 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1198 if (!sbi)
1199 return -ENOMEM;
1200 sb->s_fs_info = sbi;
1201
1202 sb->s_flags |= MS_NODIRATIME;
1203 sb->s_magic = MSDOS_SUPER_MAGIC;
1204 sb->s_op = &fat_sops;
1205 sb->s_export_op = &fat_export_ops;
1206 sbi->dir_ops = fs_dir_inode_ops;
1207
1208 error = parse_options(data, isvfat, silent, &debug, &sbi->options);
1209 if (error)
1210 goto out_fail;
1211
1212 error = -EIO;
1213 sb_min_blocksize(sb, 512);
1214 bh = sb_bread(sb, 0);
1215 if (bh == NULL) {
1216 printk(KERN_ERR "FAT: unable to read boot sector\n");
1217 goto out_fail;
1218 }
1219
1220 b = (struct fat_boot_sector *) bh->b_data;
1221 if (!b->reserved) {
1222 if (!silent)
1223 printk(KERN_ERR "FAT: bogus number of reserved sectors\n");
1224 brelse(bh);
1225 goto out_invalid;
1226 }
1227 if (!b->fats) {
1228 if (!silent)
1229 printk(KERN_ERR "FAT: bogus number of FAT structure\n");
1230 brelse(bh);
1231 goto out_invalid;
1232 }
1233
1234 /*
1235 * Earlier we checked here that b->secs_track and b->head are nonzero,
1236 * but it turns out valid FAT filesystems can have zero there.
1237 */
1238
1239 media = b->media;
1240 if (!fat_valid_media(media)) {
1241 if (!silent)
1242 printk(KERN_ERR "FAT: invalid media value (0x%02x)\n",
1243 media);
1244 brelse(bh);
1245 goto out_invalid;
1246 }
1247 logical_sector_size = get_unaligned_le16(&b->sector_size);
1248 if (!is_power_of_2(logical_sector_size)
1249 || (logical_sector_size < 512)
1250 || (logical_sector_size > 4096)) {
1251 if (!silent)
1252 printk(KERN_ERR "FAT: bogus logical sector size %u\n",
1253 logical_sector_size);
1254 brelse(bh);
1255 goto out_invalid;
1256 }
1257 sbi->sec_per_clus = b->sec_per_clus;
1258 if (!is_power_of_2(sbi->sec_per_clus)) {
1259 if (!silent)
1260 printk(KERN_ERR "FAT: bogus sectors per cluster %u\n",
1261 sbi->sec_per_clus);
1262 brelse(bh);
1263 goto out_invalid;
1264 }
1265
1266 if (logical_sector_size < sb->s_blocksize) {
1267 printk(KERN_ERR "FAT: logical sector size too small for device"
1268 " (logical sector size = %u)\n", logical_sector_size);
1269 brelse(bh);
1270 goto out_fail;
1271 }
1272 if (logical_sector_size > sb->s_blocksize) {
1273 brelse(bh);
1274
1275 if (!sb_set_blocksize(sb, logical_sector_size)) {
1276 printk(KERN_ERR "FAT: unable to set blocksize %u\n",
1277 logical_sector_size);
1278 goto out_fail;
1279 }
1280 bh = sb_bread(sb, 0);
1281 if (bh == NULL) {
1282 printk(KERN_ERR "FAT: unable to read boot sector"
1283 " (logical sector size = %lu)\n",
1284 sb->s_blocksize);
1285 goto out_fail;
1286 }
1287 b = (struct fat_boot_sector *) bh->b_data;
1288 }
1289
1290 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1291 sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1292 sbi->fats = b->fats;
1293 sbi->fat_bits = 0; /* Don't know yet */
1294 sbi->fat_start = le16_to_cpu(b->reserved);
1295 sbi->fat_length = le16_to_cpu(b->fat_length);
1296 sbi->root_cluster = 0;
1297 sbi->free_clusters = -1; /* Don't know yet */
1298 sbi->free_clus_valid = 0;
1299 sbi->prev_free = FAT_START_ENT;
1300
1301 if (!sbi->fat_length && b->fat32_length) {
1302 struct fat_boot_fsinfo *fsinfo;
1303 struct buffer_head *fsinfo_bh;
1304
1305 /* Must be FAT32 */
1306 sbi->fat_bits = 32;
1307 sbi->fat_length = le32_to_cpu(b->fat32_length);
1308 sbi->root_cluster = le32_to_cpu(b->root_cluster);
1309
1310 sb->s_maxbytes = 0xffffffff;
1311
1312 /* MC - if info_sector is 0, don't multiply by 0 */
1313 sbi->fsinfo_sector = le16_to_cpu(b->info_sector);
1314 if (sbi->fsinfo_sector == 0)
1315 sbi->fsinfo_sector = 1;
1316
1317 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1318 if (fsinfo_bh == NULL) {
1319 printk(KERN_ERR "FAT: bread failed, FSINFO block"
1320 " (sector = %lu)\n", sbi->fsinfo_sector);
1321 brelse(bh);
1322 goto out_fail;
1323 }
1324
1325 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1326 if (!IS_FSINFO(fsinfo)) {
1327 printk(KERN_WARNING "FAT: Invalid FSINFO signature: "
1328 "0x%08x, 0x%08x (sector = %lu)\n",
1329 le32_to_cpu(fsinfo->signature1),
1330 le32_to_cpu(fsinfo->signature2),
1331 sbi->fsinfo_sector);
1332 } else {
1333 if (sbi->options.usefree)
1334 sbi->free_clus_valid = 1;
1335 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1336 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1337 }
1338
1339 brelse(fsinfo_bh);
1340 }
1341
1342 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1343 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1344
1345 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1346 sbi->dir_entries = get_unaligned_le16(&b->dir_entries);
1347 if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1348 if (!silent)
1349 printk(KERN_ERR "FAT: bogus directroy-entries per block"
1350 " (%u)\n", sbi->dir_entries);
1351 brelse(bh);
1352 goto out_invalid;
1353 }
1354
1355 rootdir_sectors = sbi->dir_entries
1356 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1357 sbi->data_start = sbi->dir_start + rootdir_sectors;
1358 total_sectors = get_unaligned_le16(&b->sectors);
1359 if (total_sectors == 0)
1360 total_sectors = le32_to_cpu(b->total_sect);
1361
1362 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1363
1364 if (sbi->fat_bits != 32)
1365 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1366
1367 /* check that FAT table does not overflow */
1368 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1369 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1370 if (total_clusters > MAX_FAT(sb)) {
1371 if (!silent)
1372 printk(KERN_ERR "FAT: count of clusters too big (%u)\n",
1373 total_clusters);
1374 brelse(bh);
1375 goto out_invalid;
1376 }
1377
1378 sbi->max_cluster = total_clusters + FAT_START_ENT;
1379 /* check the free_clusters, it's not necessarily correct */
1380 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1381 sbi->free_clusters = -1;
1382 /* check the prev_free, it's not necessarily correct */
1383 sbi->prev_free %= sbi->max_cluster;
1384 if (sbi->prev_free < FAT_START_ENT)
1385 sbi->prev_free = FAT_START_ENT;
1386
1387 brelse(bh);
1388
1389 /* set up enough so that it can read an inode */
1390 fat_hash_init(sb);
1391 fat_ent_access_init(sb);
1392
1393 /*
1394 * The low byte of FAT's first entry must have same value with
1395 * media-field. But in real world, too many devices is
1396 * writing wrong value. So, removed that validity check.
1397 *
1398 * if (FAT_FIRST_ENT(sb, media) != first)
1399 */
1400
1401 error = -EINVAL;
1402 sprintf(buf, "cp%d", sbi->options.codepage);
1403 sbi->nls_disk = load_nls(buf);
1404 if (!sbi->nls_disk) {
1405 printk(KERN_ERR "FAT: codepage %s not found\n", buf);
1406 goto out_fail;
1407 }
1408
1409 /* FIXME: utf8 is using iocharset for upper/lower conversion */
1410 if (sbi->options.isvfat) {
1411 sbi->nls_io = load_nls(sbi->options.iocharset);
1412 if (!sbi->nls_io) {
1413 printk(KERN_ERR "FAT: IO charset %s not found\n",
1414 sbi->options.iocharset);
1415 goto out_fail;
1416 }
1417 }
1418
1419 error = -ENOMEM;
1420 root_inode = new_inode(sb);
1421 if (!root_inode)
1422 goto out_fail;
1423 root_inode->i_ino = MSDOS_ROOT_INO;
1424 root_inode->i_version = 1;
1425 error = fat_read_root(root_inode);
1426 if (error < 0)
1427 goto out_fail;
1428 error = -ENOMEM;
1429 insert_inode_hash(root_inode);
1430 sb->s_root = d_alloc_root(root_inode);
1431 if (!sb->s_root) {
1432 printk(KERN_ERR "FAT: get root inode failed\n");
1433 goto out_fail;
1434 }
1435
1436 return 0;
1437
1438 out_invalid:
1439 error = -EINVAL;
1440 if (!silent)
1441 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem"
1442 " on dev %s.\n", sb->s_id);
1443
1444 out_fail:
1445 if (root_inode)
1446 iput(root_inode);
1447 if (sbi->nls_io)
1448 unload_nls(sbi->nls_io);
1449 if (sbi->nls_disk)
1450 unload_nls(sbi->nls_disk);
1451 if (sbi->options.iocharset != fat_default_iocharset)
1452 kfree(sbi->options.iocharset);
1453 sb->s_fs_info = NULL;
1454 kfree(sbi);
1455 return error;
1456 }
1457
1458 EXPORT_SYMBOL_GPL(fat_fill_super);
1459
1460 /*
1461 * helper function for fat_flush_inodes. This writes both the inode
1462 * and the file data blocks, waiting for in flight data blocks before
1463 * the start of the call. It does not wait for any io started
1464 * during the call
1465 */
1466 static int writeback_inode(struct inode *inode)
1467 {
1468
1469 int ret;
1470 struct address_space *mapping = inode->i_mapping;
1471 struct writeback_control wbc = {
1472 .sync_mode = WB_SYNC_NONE,
1473 .nr_to_write = 0,
1474 };
1475 /* if we used WB_SYNC_ALL, sync_inode waits for the io for the
1476 * inode to finish. So WB_SYNC_NONE is sent down to sync_inode
1477 * and filemap_fdatawrite is used for the data blocks
1478 */
1479 ret = sync_inode(inode, &wbc);
1480 if (!ret)
1481 ret = filemap_fdatawrite(mapping);
1482 return ret;
1483 }
1484
1485 /*
1486 * write data and metadata corresponding to i1 and i2. The io is
1487 * started but we do not wait for any of it to finish.
1488 *
1489 * filemap_flush is used for the block device, so if there is a dirty
1490 * page for a block already in flight, we will not wait and start the
1491 * io over again
1492 */
1493 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1494 {
1495 int ret = 0;
1496 if (!MSDOS_SB(sb)->options.flush)
1497 return 0;
1498 if (i1)
1499 ret = writeback_inode(i1);
1500 if (!ret && i2)
1501 ret = writeback_inode(i2);
1502 if (!ret) {
1503 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
1504 ret = filemap_flush(mapping);
1505 }
1506 return ret;
1507 }
1508 EXPORT_SYMBOL_GPL(fat_flush_inodes);
1509
1510 static int __init init_fat_fs(void)
1511 {
1512 int err;
1513
1514 err = fat_cache_init();
1515 if (err)
1516 return err;
1517
1518 err = fat_init_inodecache();
1519 if (err)
1520 goto failed;
1521
1522 return 0;
1523
1524 failed:
1525 fat_cache_destroy();
1526 return err;
1527 }
1528
1529 static void __exit exit_fat_fs(void)
1530 {
1531 fat_cache_destroy();
1532 fat_destroy_inodecache();
1533 }
1534
1535 module_init(init_fat_fs)
1536 module_exit(exit_fat_fs)
1537
1538 MODULE_LICENSE("GPL");
kernel source for telekom puls (alcatel/mediatek)