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net: Make static
[linux-2.6.git] / fs / fat / inode.c
blobbdd8fb7be2ca48e5ac4e49b5b2dd147375f6c8b2
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 mutex_lock(&mapping->host->i_mutex);
206 blocknr = generic_block_bmap(mapping, block, fat_get_block);
207 mutex_unlock(&mapping->host->i_mutex);
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 msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
527
528 /* If the count of free cluster is still unknown, counts it here. */
529 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
530 int err = fat_count_free_clusters(dentry->d_sb);
531 if (err)
532 return err;
533 }
534
535 buf->f_type = dentry->d_sb->s_magic;
536 buf->f_bsize = sbi->cluster_size;
537 buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
538 buf->f_bfree = sbi->free_clusters;
539 buf->f_bavail = sbi->free_clusters;
540 buf->f_namelen = sbi->options.isvfat ? 260 : 12;
541
542 return 0;
543 }
544
545 static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi,
546 struct inode *inode)
547 {
548 loff_t i_pos;
549 #if BITS_PER_LONG == 32
550 spin_lock(&sbi->inode_hash_lock);
551 #endif
552 i_pos = MSDOS_I(inode)->i_pos;
553 #if BITS_PER_LONG == 32
554 spin_unlock(&sbi->inode_hash_lock);
555 #endif
556 return i_pos;
557 }
558
559 static int fat_write_inode(struct inode *inode, int wait)
560 {
561 struct super_block *sb = inode->i_sb;
562 struct msdos_sb_info *sbi = MSDOS_SB(sb);
563 struct buffer_head *bh;
564 struct msdos_dir_entry *raw_entry;
565 loff_t i_pos;
566 int err;
567
568 if (inode->i_ino == MSDOS_ROOT_INO)
569 return 0;
570
571 retry:
572 i_pos = fat_i_pos_read(sbi, inode);
573 if (!i_pos)
574 return 0;
575
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 return -EIO;
581 }
582 spin_lock(&sbi->inode_hash_lock);
583 if (i_pos != MSDOS_I(inode)->i_pos) {
584 spin_unlock(&sbi->inode_hash_lock);
585 brelse(bh);
586 goto retry;
587 }
588
589 raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
590 [i_pos & (sbi->dir_per_block - 1)];
591 if (S_ISDIR(inode->i_mode))
592 raw_entry->size = 0;
593 else
594 raw_entry->size = cpu_to_le32(inode->i_size);
595 raw_entry->attr = fat_make_attrs(inode);
596 raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart);
597 raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16);
598 fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
599 &raw_entry->date, NULL);
600 if (sbi->options.isvfat) {
601 __le16 atime;
602 fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime,
603 &raw_entry->cdate, &raw_entry->ctime_cs);
604 fat_time_unix2fat(sbi, &inode->i_atime, &atime,
605 &raw_entry->adate, NULL);
606 }
607 spin_unlock(&sbi->inode_hash_lock);
608 mark_buffer_dirty(bh);
609 err = 0;
610 if (wait)
611 err = sync_dirty_buffer(bh);
612 brelse(bh);
613 return err;
614 }
615
616 int fat_sync_inode(struct inode *inode)
617 {
618 return fat_write_inode(inode, 1);
619 }
620
621 EXPORT_SYMBOL_GPL(fat_sync_inode);
622
623 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt);
624 static const struct super_operations fat_sops = {
625 .alloc_inode = fat_alloc_inode,
626 .destroy_inode = fat_destroy_inode,
627 .write_inode = fat_write_inode,
628 .delete_inode = fat_delete_inode,
629 .put_super = fat_put_super,
630 .write_super = fat_write_super,
631 .statfs = fat_statfs,
632 .clear_inode = fat_clear_inode,
633 .remount_fs = fat_remount,
634
635 .show_options = fat_show_options,
636 };
637
638 /*
639 * a FAT file handle with fhtype 3 is
640 * 0/ i_ino - for fast, reliable lookup if still in the cache
641 * 1/ i_generation - to see if i_ino is still valid
642 * bit 0 == 0 iff directory
643 * 2/ i_pos(8-39) - if ino has changed, but still in cache
644 * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos
645 * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc
646 *
647 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum
648 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits
649 * of i_logstart is used to store the directory entry offset.
650 */
651
652 static struct dentry *fat_fh_to_dentry(struct super_block *sb,
653 struct fid *fid, int fh_len, int fh_type)
654 {
655 struct inode *inode = NULL;
656 struct dentry *result;
657 u32 *fh = fid->raw;
658
659 if (fh_len < 5 || fh_type != 3)
660 return NULL;
661
662 inode = ilookup(sb, fh[0]);
663 if (!inode || inode->i_generation != fh[1]) {
664 if (inode)
665 iput(inode);
666 inode = NULL;
667 }
668 if (!inode) {
669 loff_t i_pos;
670 int i_logstart = fh[3] & 0x0fffffff;
671
672 i_pos = (loff_t)fh[2] << 8;
673 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28);
674
675 /* try 2 - see if i_pos is in F-d-c
676 * require i_logstart to be the same
677 * Will fail if you truncate and then re-write
678 */
679
680 inode = fat_iget(sb, i_pos);
681 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) {
682 iput(inode);
683 inode = NULL;
684 }
685 }
686
687 /*
688 * For now, do nothing if the inode is not found.
689 *
690 * What we could do is:
691 *
692 * - follow the file starting at fh[4], and record the ".." entry,
693 * and the name of the fh[2] entry.
694 * - then follow the ".." file finding the next step up.
695 *
696 * This way we build a path to the root of the tree. If this works, we
697 * lookup the path and so get this inode into the cache. Finally try
698 * the fat_iget lookup again. If that fails, then we are totally out
699 * of luck. But all that is for another day
700 */
701 result = d_obtain_alias(inode);
702 if (!IS_ERR(result))
703 result->d_op = sb->s_root->d_op;
704 return result;
705 }
706
707 static int
708 fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable)
709 {
710 int len = *lenp;
711 struct inode *inode = de->d_inode;
712 u32 ipos_h, ipos_m, ipos_l;
713
714 if (len < 5)
715 return 255; /* no room */
716
717 ipos_h = MSDOS_I(inode)->i_pos >> 8;
718 ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24;
719 ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28;
720 *lenp = 5;
721 fh[0] = inode->i_ino;
722 fh[1] = inode->i_generation;
723 fh[2] = ipos_h;
724 fh[3] = ipos_m | MSDOS_I(inode)->i_logstart;
725 spin_lock(&de->d_lock);
726 fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart;
727 spin_unlock(&de->d_lock);
728 return 3;
729 }
730
731 static struct dentry *fat_get_parent(struct dentry *child)
732 {
733 struct super_block *sb = child->d_sb;
734 struct buffer_head *bh;
735 struct msdos_dir_entry *de;
736 loff_t i_pos;
737 struct dentry *parent;
738 struct inode *inode;
739 int err;
740
741 lock_super(sb);
742
743 err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos);
744 if (err) {
745 parent = ERR_PTR(err);
746 goto out;
747 }
748 inode = fat_build_inode(sb, de, i_pos);
749 brelse(bh);
750
751 parent = d_obtain_alias(inode);
752 out:
753 unlock_super(sb);
754
755 return parent;
756 }
757
758 static const struct export_operations fat_export_ops = {
759 .encode_fh = fat_encode_fh,
760 .fh_to_dentry = fat_fh_to_dentry,
761 .get_parent = fat_get_parent,
762 };
763
764 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt)
765 {
766 struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb);
767 struct fat_mount_options *opts = &sbi->options;
768 int isvfat = opts->isvfat;
769
770 if (opts->fs_uid != 0)
771 seq_printf(m, ",uid=%u", opts->fs_uid);
772 if (opts->fs_gid != 0)
773 seq_printf(m, ",gid=%u", opts->fs_gid);
774 seq_printf(m, ",fmask=%04o", opts->fs_fmask);
775 seq_printf(m, ",dmask=%04o", opts->fs_dmask);
776 if (opts->allow_utime)
777 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
778 if (sbi->nls_disk)
779 seq_printf(m, ",codepage=%s", sbi->nls_disk->charset);
780 if (isvfat) {
781 if (sbi->nls_io)
782 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
783
784 switch (opts->shortname) {
785 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
786 seq_puts(m, ",shortname=win95");
787 break;
788 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
789 seq_puts(m, ",shortname=winnt");
790 break;
791 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
792 seq_puts(m, ",shortname=mixed");
793 break;
794 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
795 /* seq_puts(m, ",shortname=lower"); */
796 break;
797 default:
798 seq_puts(m, ",shortname=unknown");
799 break;
800 }
801 }
802 if (opts->name_check != 'n')
803 seq_printf(m, ",check=%c", opts->name_check);
804 if (opts->usefree)
805 seq_puts(m, ",usefree");
806 if (opts->quiet)
807 seq_puts(m, ",quiet");
808 if (opts->showexec)
809 seq_puts(m, ",showexec");
810 if (opts->sys_immutable)
811 seq_puts(m, ",sys_immutable");
812 if (!isvfat) {
813 if (opts->dotsOK)
814 seq_puts(m, ",dotsOK=yes");
815 if (opts->nocase)
816 seq_puts(m, ",nocase");
817 } else {
818 if (opts->utf8)
819 seq_puts(m, ",utf8");
820 if (opts->unicode_xlate)
821 seq_puts(m, ",uni_xlate");
822 if (!opts->numtail)
823 seq_puts(m, ",nonumtail");
824 if (opts->rodir)
825 seq_puts(m, ",rodir");
826 }
827 if (opts->flush)
828 seq_puts(m, ",flush");
829 if (opts->tz_utc)
830 seq_puts(m, ",tz=UTC");
831
832 return 0;
833 }
834
835 enum {
836 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
837 Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
838 Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
839 Opt_immutable, Opt_dots, Opt_nodots,
840 Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
841 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
842 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
843 Opt_obsolate, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err,
844 };
845
846 static const match_table_t fat_tokens = {
847 {Opt_check_r, "check=relaxed"},
848 {Opt_check_s, "check=strict"},
849 {Opt_check_n, "check=normal"},
850 {Opt_check_r, "check=r"},
851 {Opt_check_s, "check=s"},
852 {Opt_check_n, "check=n"},
853 {Opt_uid, "uid=%u"},
854 {Opt_gid, "gid=%u"},
855 {Opt_umask, "umask=%o"},
856 {Opt_dmask, "dmask=%o"},
857 {Opt_fmask, "fmask=%o"},
858 {Opt_allow_utime, "allow_utime=%o"},
859 {Opt_codepage, "codepage=%u"},
860 {Opt_usefree, "usefree"},
861 {Opt_nocase, "nocase"},
862 {Opt_quiet, "quiet"},
863 {Opt_showexec, "showexec"},
864 {Opt_debug, "debug"},
865 {Opt_immutable, "sys_immutable"},
866 {Opt_obsolate, "conv=binary"},
867 {Opt_obsolate, "conv=text"},
868 {Opt_obsolate, "conv=auto"},
869 {Opt_obsolate, "conv=b"},
870 {Opt_obsolate, "conv=t"},
871 {Opt_obsolate, "conv=a"},
872 {Opt_obsolate, "fat=%u"},
873 {Opt_obsolate, "blocksize=%u"},
874 {Opt_obsolate, "cvf_format=%20s"},
875 {Opt_obsolate, "cvf_options=%100s"},
876 {Opt_obsolate, "posix"},
877 {Opt_flush, "flush"},
878 {Opt_tz_utc, "tz=UTC"},
879 {Opt_err, NULL},
880 };
881 static const match_table_t msdos_tokens = {
882 {Opt_nodots, "nodots"},
883 {Opt_nodots, "dotsOK=no"},
884 {Opt_dots, "dots"},
885 {Opt_dots, "dotsOK=yes"},
886 {Opt_err, NULL}
887 };
888 static const match_table_t vfat_tokens = {
889 {Opt_charset, "iocharset=%s"},
890 {Opt_shortname_lower, "shortname=lower"},
891 {Opt_shortname_win95, "shortname=win95"},
892 {Opt_shortname_winnt, "shortname=winnt"},
893 {Opt_shortname_mixed, "shortname=mixed"},
894 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */
895 {Opt_utf8_no, "utf8=no"},
896 {Opt_utf8_no, "utf8=false"},
897 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */
898 {Opt_utf8_yes, "utf8=yes"},
899 {Opt_utf8_yes, "utf8=true"},
900 {Opt_utf8_yes, "utf8"},
901 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */
902 {Opt_uni_xl_no, "uni_xlate=no"},
903 {Opt_uni_xl_no, "uni_xlate=false"},
904 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */
905 {Opt_uni_xl_yes, "uni_xlate=yes"},
906 {Opt_uni_xl_yes, "uni_xlate=true"},
907 {Opt_uni_xl_yes, "uni_xlate"},
908 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */
909 {Opt_nonumtail_no, "nonumtail=no"},
910 {Opt_nonumtail_no, "nonumtail=false"},
911 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */
912 {Opt_nonumtail_yes, "nonumtail=yes"},
913 {Opt_nonumtail_yes, "nonumtail=true"},
914 {Opt_nonumtail_yes, "nonumtail"},
915 {Opt_rodir, "rodir"},
916 {Opt_err, NULL}
917 };
918
919 static int parse_options(char *options, int is_vfat, int silent, int *debug,
920 struct fat_mount_options *opts)
921 {
922 char *p;
923 substring_t args[MAX_OPT_ARGS];
924 int option;
925 char *iocharset;
926
927 opts->isvfat = is_vfat;
928
929 opts->fs_uid = current->uid;
930 opts->fs_gid = current->gid;
931 opts->fs_fmask = opts->fs_dmask = current->fs->umask;
932 opts->allow_utime = -1;
933 opts->codepage = fat_default_codepage;
934 opts->iocharset = fat_default_iocharset;
935 if (is_vfat) {
936 opts->shortname = VFAT_SFN_DISPLAY_LOWER|VFAT_SFN_CREATE_WIN95;
937 opts->rodir = 0;
938 } else {
939 opts->shortname = 0;
940 opts->rodir = 1;
941 }
942 opts->name_check = 'n';
943 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0;
944 opts->utf8 = opts->unicode_xlate = 0;
945 opts->numtail = 1;
946 opts->usefree = opts->nocase = 0;
947 opts->tz_utc = 0;
948 *debug = 0;
949
950 if (!options)
951 goto out;
952
953 while ((p = strsep(&options, ",")) != NULL) {
954 int token;
955 if (!*p)
956 continue;
957
958 token = match_token(p, fat_tokens, args);
959 if (token == Opt_err) {
960 if (is_vfat)
961 token = match_token(p, vfat_tokens, args);
962 else
963 token = match_token(p, msdos_tokens, args);
964 }
965 switch (token) {
966 case Opt_check_s:
967 opts->name_check = 's';
968 break;
969 case Opt_check_r:
970 opts->name_check = 'r';
971 break;
972 case Opt_check_n:
973 opts->name_check = 'n';
974 break;
975 case Opt_usefree:
976 opts->usefree = 1;
977 break;
978 case Opt_nocase:
979 if (!is_vfat)
980 opts->nocase = 1;
981 else {
982 /* for backward compatibility */
983 opts->shortname = VFAT_SFN_DISPLAY_WIN95
984 | VFAT_SFN_CREATE_WIN95;
985 }
986 break;
987 case Opt_quiet:
988 opts->quiet = 1;
989 break;
990 case Opt_showexec:
991 opts->showexec = 1;
992 break;
993 case Opt_debug:
994 *debug = 1;
995 break;
996 case Opt_immutable:
997 opts->sys_immutable = 1;
998 break;
999 case Opt_uid:
1000 if (match_int(&args[0], &option))
1001 return 0;
1002 opts->fs_uid = option;
1003 break;
1004 case Opt_gid:
1005 if (match_int(&args[0], &option))
1006 return 0;
1007 opts->fs_gid = option;
1008 break;
1009 case Opt_umask:
1010 if (match_octal(&args[0], &option))
1011 return 0;
1012 opts->fs_fmask = opts->fs_dmask = option;
1013 break;
1014 case Opt_dmask:
1015 if (match_octal(&args[0], &option))
1016 return 0;
1017 opts->fs_dmask = option;
1018 break;
1019 case Opt_fmask:
1020 if (match_octal(&args[0], &option))
1021 return 0;
1022 opts->fs_fmask = option;
1023 break;
1024 case Opt_allow_utime:
1025 if (match_octal(&args[0], &option))
1026 return 0;
1027 opts->allow_utime = option & (S_IWGRP | S_IWOTH);
1028 break;
1029 case Opt_codepage:
1030 if (match_int(&args[0], &option))
1031 return 0;
1032 opts->codepage = option;
1033 break;
1034 case Opt_flush:
1035 opts->flush = 1;
1036 break;
1037 case Opt_tz_utc:
1038 opts->tz_utc = 1;
1039 break;
1040
1041 /* msdos specific */
1042 case Opt_dots:
1043 opts->dotsOK = 1;
1044 break;
1045 case Opt_nodots:
1046 opts->dotsOK = 0;
1047 break;
1048
1049 /* vfat specific */
1050 case Opt_charset:
1051 if (opts->iocharset != fat_default_iocharset)
1052 kfree(opts->iocharset);
1053 iocharset = match_strdup(&args[0]);
1054 if (!iocharset)
1055 return -ENOMEM;
1056 opts->iocharset = iocharset;
1057 break;
1058 case Opt_shortname_lower:
1059 opts->shortname = VFAT_SFN_DISPLAY_LOWER
1060 | VFAT_SFN_CREATE_WIN95;
1061 break;
1062 case Opt_shortname_win95:
1063 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1064 | VFAT_SFN_CREATE_WIN95;
1065 break;
1066 case Opt_shortname_winnt:
1067 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1068 | VFAT_SFN_CREATE_WINNT;
1069 break;
1070 case Opt_shortname_mixed:
1071 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1072 | VFAT_SFN_CREATE_WIN95;
1073 break;
1074 case Opt_utf8_no: /* 0 or no or false */
1075 opts->utf8 = 0;
1076 break;
1077 case Opt_utf8_yes: /* empty or 1 or yes or true */
1078 opts->utf8 = 1;
1079 break;
1080 case Opt_uni_xl_no: /* 0 or no or false */
1081 opts->unicode_xlate = 0;
1082 break;
1083 case Opt_uni_xl_yes: /* empty or 1 or yes or true */
1084 opts->unicode_xlate = 1;
1085 break;
1086 case Opt_nonumtail_no: /* 0 or no or false */
1087 opts->numtail = 1; /* negated option */
1088 break;
1089 case Opt_nonumtail_yes: /* empty or 1 or yes or true */
1090 opts->numtail = 0; /* negated option */
1091 break;
1092 case Opt_rodir:
1093 opts->rodir = 1;
1094 break;
1095
1096 /* obsolete mount options */
1097 case Opt_obsolate:
1098 printk(KERN_INFO "FAT: \"%s\" option is obsolete, "
1099 "not supported now\n", p);
1100 break;
1101 /* unknown option */
1102 default:
1103 if (!silent) {
1104 printk(KERN_ERR
1105 "FAT: Unrecognized mount option \"%s\" "
1106 "or missing value\n", p);
1107 }
1108 return -EINVAL;
1109 }
1110 }
1111
1112 out:
1113 /* UTF-8 doesn't provide FAT semantics */
1114 if (!strcmp(opts->iocharset, "utf8")) {
1115 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset"
1116 " for FAT filesystems, filesystem will be "
1117 "case sensitive!\n");
1118 }
1119
1120 /* If user doesn't specify allow_utime, it's initialized from dmask. */
1121 if (opts->allow_utime == (unsigned short)-1)
1122 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1123 if (opts->unicode_xlate)
1124 opts->utf8 = 0;
1125
1126 return 0;
1127 }
1128
1129 static int fat_read_root(struct inode *inode)
1130 {
1131 struct super_block *sb = inode->i_sb;
1132 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1133 int error;
1134
1135 MSDOS_I(inode)->i_pos = 0;
1136 inode->i_uid = sbi->options.fs_uid;
1137 inode->i_gid = sbi->options.fs_gid;
1138 inode->i_version++;
1139 inode->i_generation = 0;
1140 inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
1141 inode->i_op = sbi->dir_ops;
1142 inode->i_fop = &fat_dir_operations;
1143 if (sbi->fat_bits == 32) {
1144 MSDOS_I(inode)->i_start = sbi->root_cluster;
1145 error = fat_calc_dir_size(inode);
1146 if (error < 0)
1147 return error;
1148 } else {
1149 MSDOS_I(inode)->i_start = 0;
1150 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1151 }
1152 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1153 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1154 MSDOS_I(inode)->i_logstart = 0;
1155 MSDOS_I(inode)->mmu_private = inode->i_size;
1156
1157 fat_save_attrs(inode, ATTR_DIR);
1158 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1159 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1160 inode->i_nlink = fat_subdirs(inode)+2;
1161
1162 return 0;
1163 }
1164
1165 /*
1166 * Read the super block of an MS-DOS FS.
1167 */
1168 int fat_fill_super(struct super_block *sb, void *data, int silent,
1169 const struct inode_operations *fs_dir_inode_ops, int isvfat)
1170 {
1171 struct inode *root_inode = NULL;
1172 struct buffer_head *bh;
1173 struct fat_boot_sector *b;
1174 struct msdos_sb_info *sbi;
1175 u16 logical_sector_size;
1176 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1177 int debug;
1178 unsigned int media;
1179 long error;
1180 char buf[50];
1181
1182 /*
1183 * GFP_KERNEL is ok here, because while we do hold the
1184 * supeblock lock, memory pressure can't call back into
1185 * the filesystem, since we're only just about to mount
1186 * it and have no inodes etc active!
1187 */
1188 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1189 if (!sbi)
1190 return -ENOMEM;
1191 sb->s_fs_info = sbi;
1192
1193 sb->s_flags |= MS_NODIRATIME;
1194 sb->s_magic = MSDOS_SUPER_MAGIC;
1195 sb->s_op = &fat_sops;
1196 sb->s_export_op = &fat_export_ops;
1197 sbi->dir_ops = fs_dir_inode_ops;
1198
1199 error = parse_options(data, isvfat, silent, &debug, &sbi->options);
1200 if (error)
1201 goto out_fail;
1202
1203 error = -EIO;
1204 sb_min_blocksize(sb, 512);
1205 bh = sb_bread(sb, 0);
1206 if (bh == NULL) {
1207 printk(KERN_ERR "FAT: unable to read boot sector\n");
1208 goto out_fail;
1209 }
1210
1211 b = (struct fat_boot_sector *) bh->b_data;
1212 if (!b->reserved) {
1213 if (!silent)
1214 printk(KERN_ERR "FAT: bogus number of reserved sectors\n");
1215 brelse(bh);
1216 goto out_invalid;
1217 }
1218 if (!b->fats) {
1219 if (!silent)
1220 printk(KERN_ERR "FAT: bogus number of FAT structure\n");
1221 brelse(bh);
1222 goto out_invalid;
1223 }
1224
1225 /*
1226 * Earlier we checked here that b->secs_track and b->head are nonzero,
1227 * but it turns out valid FAT filesystems can have zero there.
1228 */
1229
1230 media = b->media;
1231 if (!fat_valid_media(media)) {
1232 if (!silent)
1233 printk(KERN_ERR "FAT: invalid media value (0x%02x)\n",
1234 media);
1235 brelse(bh);
1236 goto out_invalid;
1237 }
1238 logical_sector_size = get_unaligned_le16(&b->sector_size);
1239 if (!is_power_of_2(logical_sector_size)
1240 || (logical_sector_size < 512)
1241 || (logical_sector_size > 4096)) {
1242 if (!silent)
1243 printk(KERN_ERR "FAT: bogus logical sector size %u\n",
1244 logical_sector_size);
1245 brelse(bh);
1246 goto out_invalid;
1247 }
1248 sbi->sec_per_clus = b->sec_per_clus;
1249 if (!is_power_of_2(sbi->sec_per_clus)) {
1250 if (!silent)
1251 printk(KERN_ERR "FAT: bogus sectors per cluster %u\n",
1252 sbi->sec_per_clus);
1253 brelse(bh);
1254 goto out_invalid;
1255 }
1256
1257 if (logical_sector_size < sb->s_blocksize) {
1258 printk(KERN_ERR "FAT: logical sector size too small for device"
1259 " (logical sector size = %u)\n", logical_sector_size);
1260 brelse(bh);
1261 goto out_fail;
1262 }
1263 if (logical_sector_size > sb->s_blocksize) {
1264 brelse(bh);
1265
1266 if (!sb_set_blocksize(sb, logical_sector_size)) {
1267 printk(KERN_ERR "FAT: unable to set blocksize %u\n",
1268 logical_sector_size);
1269 goto out_fail;
1270 }
1271 bh = sb_bread(sb, 0);
1272 if (bh == NULL) {
1273 printk(KERN_ERR "FAT: unable to read boot sector"
1274 " (logical sector size = %lu)\n",
1275 sb->s_blocksize);
1276 goto out_fail;
1277 }
1278 b = (struct fat_boot_sector *) bh->b_data;
1279 }
1280
1281 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1282 sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1283 sbi->fats = b->fats;
1284 sbi->fat_bits = 0; /* Don't know yet */
1285 sbi->fat_start = le16_to_cpu(b->reserved);
1286 sbi->fat_length = le16_to_cpu(b->fat_length);
1287 sbi->root_cluster = 0;
1288 sbi->free_clusters = -1; /* Don't know yet */
1289 sbi->free_clus_valid = 0;
1290 sbi->prev_free = FAT_START_ENT;
1291
1292 if (!sbi->fat_length && b->fat32_length) {
1293 struct fat_boot_fsinfo *fsinfo;
1294 struct buffer_head *fsinfo_bh;
1295
1296 /* Must be FAT32 */
1297 sbi->fat_bits = 32;
1298 sbi->fat_length = le32_to_cpu(b->fat32_length);
1299 sbi->root_cluster = le32_to_cpu(b->root_cluster);
1300
1301 sb->s_maxbytes = 0xffffffff;
1302
1303 /* MC - if info_sector is 0, don't multiply by 0 */
1304 sbi->fsinfo_sector = le16_to_cpu(b->info_sector);
1305 if (sbi->fsinfo_sector == 0)
1306 sbi->fsinfo_sector = 1;
1307
1308 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1309 if (fsinfo_bh == NULL) {
1310 printk(KERN_ERR "FAT: bread failed, FSINFO block"
1311 " (sector = %lu)\n", sbi->fsinfo_sector);
1312 brelse(bh);
1313 goto out_fail;
1314 }
1315
1316 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1317 if (!IS_FSINFO(fsinfo)) {
1318 printk(KERN_WARNING "FAT: Invalid FSINFO signature: "
1319 "0x%08x, 0x%08x (sector = %lu)\n",
1320 le32_to_cpu(fsinfo->signature1),
1321 le32_to_cpu(fsinfo->signature2),
1322 sbi->fsinfo_sector);
1323 } else {
1324 if (sbi->options.usefree)
1325 sbi->free_clus_valid = 1;
1326 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1327 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1328 }
1329
1330 brelse(fsinfo_bh);
1331 }
1332
1333 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1334 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1335
1336 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1337 sbi->dir_entries = get_unaligned_le16(&b->dir_entries);
1338 if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1339 if (!silent)
1340 printk(KERN_ERR "FAT: bogus directroy-entries per block"
1341 " (%u)\n", sbi->dir_entries);
1342 brelse(bh);
1343 goto out_invalid;
1344 }
1345
1346 rootdir_sectors = sbi->dir_entries
1347 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1348 sbi->data_start = sbi->dir_start + rootdir_sectors;
1349 total_sectors = get_unaligned_le16(&b->sectors);
1350 if (total_sectors == 0)
1351 total_sectors = le32_to_cpu(b->total_sect);
1352
1353 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1354
1355 if (sbi->fat_bits != 32)
1356 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1357
1358 /* check that FAT table does not overflow */
1359 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1360 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1361 if (total_clusters > MAX_FAT(sb)) {
1362 if (!silent)
1363 printk(KERN_ERR "FAT: count of clusters too big (%u)\n",
1364 total_clusters);
1365 brelse(bh);
1366 goto out_invalid;
1367 }
1368
1369 sbi->max_cluster = total_clusters + FAT_START_ENT;
1370 /* check the free_clusters, it's not necessarily correct */
1371 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1372 sbi->free_clusters = -1;
1373 /* check the prev_free, it's not necessarily correct */
1374 sbi->prev_free %= sbi->max_cluster;
1375 if (sbi->prev_free < FAT_START_ENT)
1376 sbi->prev_free = FAT_START_ENT;
1377
1378 brelse(bh);
1379
1380 /* set up enough so that it can read an inode */
1381 fat_hash_init(sb);
1382 fat_ent_access_init(sb);
1383
1384 /*
1385 * The low byte of FAT's first entry must have same value with
1386 * media-field. But in real world, too many devices is
1387 * writing wrong value. So, removed that validity check.
1388 *
1389 * if (FAT_FIRST_ENT(sb, media) != first)
1390 */
1391
1392 error = -EINVAL;
1393 sprintf(buf, "cp%d", sbi->options.codepage);
1394 sbi->nls_disk = load_nls(buf);
1395 if (!sbi->nls_disk) {
1396 printk(KERN_ERR "FAT: codepage %s not found\n", buf);
1397 goto out_fail;
1398 }
1399
1400 /* FIXME: utf8 is using iocharset for upper/lower conversion */
1401 if (sbi->options.isvfat) {
1402 sbi->nls_io = load_nls(sbi->options.iocharset);
1403 if (!sbi->nls_io) {
1404 printk(KERN_ERR "FAT: IO charset %s not found\n",
1405 sbi->options.iocharset);
1406 goto out_fail;
1407 }
1408 }
1409
1410 error = -ENOMEM;
1411 root_inode = new_inode(sb);
1412 if (!root_inode)
1413 goto out_fail;
1414 root_inode->i_ino = MSDOS_ROOT_INO;
1415 root_inode->i_version = 1;
1416 error = fat_read_root(root_inode);
1417 if (error < 0)
1418 goto out_fail;
1419 error = -ENOMEM;
1420 insert_inode_hash(root_inode);
1421 sb->s_root = d_alloc_root(root_inode);
1422 if (!sb->s_root) {
1423 printk(KERN_ERR "FAT: get root inode failed\n");
1424 goto out_fail;
1425 }
1426
1427 return 0;
1428
1429 out_invalid:
1430 error = -EINVAL;
1431 if (!silent)
1432 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem"
1433 " on dev %s.\n", sb->s_id);
1434
1435 out_fail:
1436 if (root_inode)
1437 iput(root_inode);
1438 if (sbi->nls_io)
1439 unload_nls(sbi->nls_io);
1440 if (sbi->nls_disk)
1441 unload_nls(sbi->nls_disk);
1442 if (sbi->options.iocharset != fat_default_iocharset)
1443 kfree(sbi->options.iocharset);
1444 sb->s_fs_info = NULL;
1445 kfree(sbi);
1446 return error;
1447 }
1448
1449 EXPORT_SYMBOL_GPL(fat_fill_super);
1450
1451 /*
1452 * helper function for fat_flush_inodes. This writes both the inode
1453 * and the file data blocks, waiting for in flight data blocks before
1454 * the start of the call. It does not wait for any io started
1455 * during the call
1456 */
1457 static int writeback_inode(struct inode *inode)
1458 {
1459
1460 int ret;
1461 struct address_space *mapping = inode->i_mapping;
1462 struct writeback_control wbc = {
1463 .sync_mode = WB_SYNC_NONE,
1464 .nr_to_write = 0,
1465 };
1466 /* if we used WB_SYNC_ALL, sync_inode waits for the io for the
1467 * inode to finish. So WB_SYNC_NONE is sent down to sync_inode
1468 * and filemap_fdatawrite is used for the data blocks
1469 */
1470 ret = sync_inode(inode, &wbc);
1471 if (!ret)
1472 ret = filemap_fdatawrite(mapping);
1473 return ret;
1474 }
1475
1476 /*
1477 * write data and metadata corresponding to i1 and i2. The io is
1478 * started but we do not wait for any of it to finish.
1479 *
1480 * filemap_flush is used for the block device, so if there is a dirty
1481 * page for a block already in flight, we will not wait and start the
1482 * io over again
1483 */
1484 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1485 {
1486 int ret = 0;
1487 if (!MSDOS_SB(sb)->options.flush)
1488 return 0;
1489 if (i1)
1490 ret = writeback_inode(i1);
1491 if (!ret && i2)
1492 ret = writeback_inode(i2);
1493 if (!ret) {
1494 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
1495 ret = filemap_flush(mapping);
1496 }
1497 return ret;
1498 }
1499 EXPORT_SYMBOL_GPL(fat_flush_inodes);
1500
1501 static int __init init_fat_fs(void)
1502 {
1503 int err;
1504
1505 err = fat_cache_init();
1506 if (err)
1507 return err;
1508
1509 err = fat_init_inodecache();
1510 if (err)
1511 goto failed;
1512
1513 return 0;
1514
1515 failed:
1516 fat_cache_destroy();
1517 return err;
1518 }
1519
1520 static void __exit exit_fat_fs(void)
1521 {
1522 fat_cache_destroy();
1523 fat_destroy_inodecache();
1524 }
1525
1526 module_init(init_fat_fs)
1527 module_exit(exit_fat_fs)
1528
1529 MODULE_LICENSE("GPL");
Linus' kernel tree