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fat: mark fs as dirty on mount and clean on umount
[deliverable/linux.git] / fs / fat / inode.c
1 /*
2 * linux/fs/fat/inode.c
3 *
4 * Written 1992,1993 by Werner Almesberger
5 * VFAT extensions by Gordon Chaffee, merged with msdos fs by Henrik Storner
6 * Rewritten for the constant inumbers support by Al Viro
7 *
8 * Fixes:
9 *
10 * Max Cohan: Fixed invalid FSINFO offset when info_sector is 0
11 */
12
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/time.h>
16 #include <linux/slab.h>
17 #include <linux/seq_file.h>
18 #include <linux/pagemap.h>
19 #include <linux/mpage.h>
20 #include <linux/buffer_head.h>
21 #include <linux/exportfs.h>
22 #include <linux/mount.h>
23 #include <linux/vfs.h>
24 #include <linux/parser.h>
25 #include <linux/uio.h>
26 #include <linux/writeback.h>
27 #include <linux/log2.h>
28 #include <linux/hash.h>
29 #include <linux/blkdev.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_error(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 void fat_write_failed(struct address_space *mapping, loff_t to)
146 {
147 struct inode *inode = mapping->host;
148
149 if (to > inode->i_size) {
150 truncate_pagecache(inode, to, inode->i_size);
151 fat_truncate_blocks(inode, inode->i_size);
152 }
153 }
154
155 static int fat_write_begin(struct file *file, struct address_space *mapping,
156 loff_t pos, unsigned len, unsigned flags,
157 struct page **pagep, void **fsdata)
158 {
159 int err;
160
161 *pagep = NULL;
162 err = cont_write_begin(file, mapping, pos, len, flags,
163 pagep, fsdata, fat_get_block,
164 &MSDOS_I(mapping->host)->mmu_private);
165 if (err < 0)
166 fat_write_failed(mapping, pos + len);
167 return err;
168 }
169
170 static int fat_write_end(struct file *file, struct address_space *mapping,
171 loff_t pos, unsigned len, unsigned copied,
172 struct page *pagep, void *fsdata)
173 {
174 struct inode *inode = mapping->host;
175 int err;
176 err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
177 if (err < len)
178 fat_write_failed(mapping, pos + len);
179 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
180 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
181 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
182 mark_inode_dirty(inode);
183 }
184 return err;
185 }
186
187 static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
188 const struct iovec *iov,
189 loff_t offset, unsigned long nr_segs)
190 {
191 struct file *file = iocb->ki_filp;
192 struct address_space *mapping = file->f_mapping;
193 struct inode *inode = mapping->host;
194 ssize_t ret;
195
196 if (rw == WRITE) {
197 /*
198 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
199 * so we need to update the ->mmu_private to block boundary.
200 *
201 * But we must fill the remaining area or hole by nul for
202 * updating ->mmu_private.
203 *
204 * Return 0, and fallback to normal buffered write.
205 */
206 loff_t size = offset + iov_length(iov, nr_segs);
207 if (MSDOS_I(inode)->mmu_private < size)
208 return 0;
209 }
210
211 /*
212 * FAT need to use the DIO_LOCKING for avoiding the race
213 * condition of fat_get_block() and ->truncate().
214 */
215 ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
216 fat_get_block);
217 if (ret < 0 && (rw & WRITE))
218 fat_write_failed(mapping, offset + iov_length(iov, nr_segs));
219
220 return ret;
221 }
222
223 static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
224 {
225 sector_t blocknr;
226
227 /* fat_get_cluster() assumes the requested blocknr isn't truncated. */
228 down_read(&MSDOS_I(mapping->host)->truncate_lock);
229 blocknr = generic_block_bmap(mapping, block, fat_get_block);
230 up_read(&MSDOS_I(mapping->host)->truncate_lock);
231
232 return blocknr;
233 }
234
235 static const struct address_space_operations fat_aops = {
236 .readpage = fat_readpage,
237 .readpages = fat_readpages,
238 .writepage = fat_writepage,
239 .writepages = fat_writepages,
240 .write_begin = fat_write_begin,
241 .write_end = fat_write_end,
242 .direct_IO = fat_direct_IO,
243 .bmap = _fat_bmap
244 };
245
246 /*
247 * New FAT inode stuff. We do the following:
248 * a) i_ino is constant and has nothing with on-disk location.
249 * b) FAT manages its own cache of directory entries.
250 * c) *This* cache is indexed by on-disk location.
251 * d) inode has an associated directory entry, all right, but
252 * it may be unhashed.
253 * e) currently entries are stored within struct inode. That should
254 * change.
255 * f) we deal with races in the following way:
256 * 1. readdir() and lookup() do FAT-dir-cache lookup.
257 * 2. rename() unhashes the F-d-c entry and rehashes it in
258 * a new place.
259 * 3. unlink() and rmdir() unhash F-d-c entry.
260 * 4. fat_write_inode() checks whether the thing is unhashed.
261 * If it is we silently return. If it isn't we do bread(),
262 * check if the location is still valid and retry if it
263 * isn't. Otherwise we do changes.
264 * 5. Spinlock is used to protect hash/unhash/location check/lookup
265 * 6. fat_evict_inode() unhashes the F-d-c entry.
266 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry
267 * and consider negative result as cache miss.
268 */
269
270 static void fat_hash_init(struct super_block *sb)
271 {
272 struct msdos_sb_info *sbi = MSDOS_SB(sb);
273 int i;
274
275 spin_lock_init(&sbi->inode_hash_lock);
276 for (i = 0; i < FAT_HASH_SIZE; i++)
277 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
278 }
279
280 static inline unsigned long fat_hash(loff_t i_pos)
281 {
282 return hash_32(i_pos, FAT_HASH_BITS);
283 }
284
285 static void dir_hash_init(struct super_block *sb)
286 {
287 struct msdos_sb_info *sbi = MSDOS_SB(sb);
288 int i;
289
290 spin_lock_init(&sbi->dir_hash_lock);
291 for (i = 0; i < FAT_HASH_SIZE; i++)
292 INIT_HLIST_HEAD(&sbi->dir_hashtable[i]);
293 }
294
295 void fat_attach(struct inode *inode, loff_t i_pos)
296 {
297 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
298
299 if (inode->i_ino != MSDOS_ROOT_INO) {
300 struct hlist_head *head = sbi->inode_hashtable
301 + fat_hash(i_pos);
302
303 spin_lock(&sbi->inode_hash_lock);
304 MSDOS_I(inode)->i_pos = i_pos;
305 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
306 spin_unlock(&sbi->inode_hash_lock);
307 }
308
309 /* If NFS support is enabled, cache the mapping of start cluster
310 * to directory inode. This is used during reconnection of
311 * dentries to the filesystem root.
312 */
313 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
314 struct hlist_head *d_head = sbi->dir_hashtable;
315 d_head += fat_dir_hash(MSDOS_I(inode)->i_logstart);
316
317 spin_lock(&sbi->dir_hash_lock);
318 hlist_add_head(&MSDOS_I(inode)->i_dir_hash, d_head);
319 spin_unlock(&sbi->dir_hash_lock);
320 }
321 }
322 EXPORT_SYMBOL_GPL(fat_attach);
323
324 void fat_detach(struct inode *inode)
325 {
326 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
327 spin_lock(&sbi->inode_hash_lock);
328 MSDOS_I(inode)->i_pos = 0;
329 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
330 spin_unlock(&sbi->inode_hash_lock);
331
332 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
333 spin_lock(&sbi->dir_hash_lock);
334 hlist_del_init(&MSDOS_I(inode)->i_dir_hash);
335 spin_unlock(&sbi->dir_hash_lock);
336 }
337 }
338 EXPORT_SYMBOL_GPL(fat_detach);
339
340 struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
341 {
342 struct msdos_sb_info *sbi = MSDOS_SB(sb);
343 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
344 struct hlist_node *_p;
345 struct msdos_inode_info *i;
346 struct inode *inode = NULL;
347
348 spin_lock(&sbi->inode_hash_lock);
349 hlist_for_each_entry(i, _p, head, i_fat_hash) {
350 BUG_ON(i->vfs_inode.i_sb != sb);
351 if (i->i_pos != i_pos)
352 continue;
353 inode = igrab(&i->vfs_inode);
354 if (inode)
355 break;
356 }
357 spin_unlock(&sbi->inode_hash_lock);
358 return inode;
359 }
360
361 static int is_exec(unsigned char *extension)
362 {
363 unsigned char *exe_extensions = "EXECOMBAT", *walk;
364
365 for (walk = exe_extensions; *walk; walk += 3)
366 if (!strncmp(extension, walk, 3))
367 return 1;
368 return 0;
369 }
370
371 static int fat_calc_dir_size(struct inode *inode)
372 {
373 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
374 int ret, fclus, dclus;
375
376 inode->i_size = 0;
377 if (MSDOS_I(inode)->i_start == 0)
378 return 0;
379
380 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
381 if (ret < 0)
382 return ret;
383 inode->i_size = (fclus + 1) << sbi->cluster_bits;
384
385 return 0;
386 }
387
388 /* doesn't deal with root inode */
389 static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
390 {
391 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
392 int error;
393
394 MSDOS_I(inode)->i_pos = 0;
395 inode->i_uid = sbi->options.fs_uid;
396 inode->i_gid = sbi->options.fs_gid;
397 inode->i_version++;
398 inode->i_generation = get_seconds();
399
400 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
401 inode->i_generation &= ~1;
402 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
403 inode->i_op = sbi->dir_ops;
404 inode->i_fop = &fat_dir_operations;
405
406 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
407 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
408 error = fat_calc_dir_size(inode);
409 if (error < 0)
410 return error;
411 MSDOS_I(inode)->mmu_private = inode->i_size;
412
413 set_nlink(inode, fat_subdirs(inode));
414 } else { /* not a directory */
415 inode->i_generation |= 1;
416 inode->i_mode = fat_make_mode(sbi, de->attr,
417 ((sbi->options.showexec && !is_exec(de->name + 8))
418 ? S_IRUGO|S_IWUGO : S_IRWXUGO));
419 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
420
421 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
422 inode->i_size = le32_to_cpu(de->size);
423 inode->i_op = &fat_file_inode_operations;
424 inode->i_fop = &fat_file_operations;
425 inode->i_mapping->a_ops = &fat_aops;
426 MSDOS_I(inode)->mmu_private = inode->i_size;
427 }
428 if (de->attr & ATTR_SYS) {
429 if (sbi->options.sys_immutable)
430 inode->i_flags |= S_IMMUTABLE;
431 }
432 fat_save_attrs(inode, de->attr);
433
434 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
435 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
436
437 fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0);
438 if (sbi->options.isvfat) {
439 fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime,
440 de->cdate, de->ctime_cs);
441 fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
442 } else
443 inode->i_ctime = inode->i_atime = inode->i_mtime;
444
445 return 0;
446 }
447
448 struct inode *fat_build_inode(struct super_block *sb,
449 struct msdos_dir_entry *de, loff_t i_pos)
450 {
451 struct inode *inode;
452 int err;
453
454 inode = fat_iget(sb, i_pos);
455 if (inode)
456 goto out;
457 inode = new_inode(sb);
458 if (!inode) {
459 inode = ERR_PTR(-ENOMEM);
460 goto out;
461 }
462 inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
463 inode->i_version = 1;
464 err = fat_fill_inode(inode, de);
465 if (err) {
466 iput(inode);
467 inode = ERR_PTR(err);
468 goto out;
469 }
470 fat_attach(inode, i_pos);
471 insert_inode_hash(inode);
472 out:
473 return inode;
474 }
475
476 EXPORT_SYMBOL_GPL(fat_build_inode);
477
478 static void fat_evict_inode(struct inode *inode)
479 {
480 truncate_inode_pages(&inode->i_data, 0);
481 if (!inode->i_nlink) {
482 inode->i_size = 0;
483 fat_truncate_blocks(inode, 0);
484 }
485 invalidate_inode_buffers(inode);
486 clear_inode(inode);
487 fat_cache_inval_inode(inode);
488 fat_detach(inode);
489 }
490
491 static void fat_set_state(struct super_block *sb,
492 unsigned int set, unsigned int force)
493 {
494 struct buffer_head *bh;
495 struct fat_boot_sector *b;
496 struct msdos_sb_info *sbi = sb->s_fs_info;
497
498 /* do not change any thing if mounted read only */
499 if ((sb->s_flags & MS_RDONLY) && !force)
500 return;
501
502 /* do not change state if fs was dirty */
503 if (sbi->dirty) {
504 /* warn only on set (mount). */
505 if (set)
506 fat_msg(sb, KERN_WARNING, "Volume was not properly "
507 "unmounted. Some data may be corrupt. "
508 "Please run fsck.");
509 return;
510 }
511
512 bh = sb_bread(sb, 0);
513 if (bh == NULL) {
514 fat_msg(sb, KERN_ERR, "unable to read boot sector "
515 "to mark fs as dirty");
516 return;
517 }
518
519 b = (struct fat_boot_sector *) bh->b_data;
520
521 if (sbi->fat_bits == 32) {
522 if (set)
523 b->fat32.state |= FAT_STATE_DIRTY;
524 else
525 b->fat32.state &= ~FAT_STATE_DIRTY;
526 } else /* fat 16 and 12 */ {
527 if (set)
528 b->fat16.state |= FAT_STATE_DIRTY;
529 else
530 b->fat16.state &= ~FAT_STATE_DIRTY;
531 }
532
533 mark_buffer_dirty(bh);
534 sync_dirty_buffer(bh);
535 brelse(bh);
536 }
537
538 static void fat_put_super(struct super_block *sb)
539 {
540 struct msdos_sb_info *sbi = MSDOS_SB(sb);
541
542 fat_set_state(sb, 0, 0);
543
544 iput(sbi->fsinfo_inode);
545 iput(sbi->fat_inode);
546
547 unload_nls(sbi->nls_disk);
548 unload_nls(sbi->nls_io);
549
550 if (sbi->options.iocharset != fat_default_iocharset)
551 kfree(sbi->options.iocharset);
552
553 sb->s_fs_info = NULL;
554 kfree(sbi);
555 }
556
557 static struct kmem_cache *fat_inode_cachep;
558
559 static struct inode *fat_alloc_inode(struct super_block *sb)
560 {
561 struct msdos_inode_info *ei;
562 ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
563 if (!ei)
564 return NULL;
565
566 init_rwsem(&ei->truncate_lock);
567 return &ei->vfs_inode;
568 }
569
570 static void fat_i_callback(struct rcu_head *head)
571 {
572 struct inode *inode = container_of(head, struct inode, i_rcu);
573 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
574 }
575
576 static void fat_destroy_inode(struct inode *inode)
577 {
578 call_rcu(&inode->i_rcu, fat_i_callback);
579 }
580
581 static void init_once(void *foo)
582 {
583 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
584
585 spin_lock_init(&ei->cache_lru_lock);
586 ei->nr_caches = 0;
587 ei->cache_valid_id = FAT_CACHE_VALID + 1;
588 INIT_LIST_HEAD(&ei->cache_lru);
589 INIT_HLIST_NODE(&ei->i_fat_hash);
590 INIT_HLIST_NODE(&ei->i_dir_hash);
591 inode_init_once(&ei->vfs_inode);
592 }
593
594 static int __init fat_init_inodecache(void)
595 {
596 fat_inode_cachep = kmem_cache_create("fat_inode_cache",
597 sizeof(struct msdos_inode_info),
598 0, (SLAB_RECLAIM_ACCOUNT|
599 SLAB_MEM_SPREAD),
600 init_once);
601 if (fat_inode_cachep == NULL)
602 return -ENOMEM;
603 return 0;
604 }
605
606 static void __exit fat_destroy_inodecache(void)
607 {
608 /*
609 * Make sure all delayed rcu free inodes are flushed before we
610 * destroy cache.
611 */
612 rcu_barrier();
613 kmem_cache_destroy(fat_inode_cachep);
614 }
615
616 static int fat_remount(struct super_block *sb, int *flags, char *data)
617 {
618 int new_rdonly;
619 struct msdos_sb_info *sbi = MSDOS_SB(sb);
620 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME);
621
622 /* make sure we update state on remount. */
623 new_rdonly = *flags & MS_RDONLY;
624 if (new_rdonly != (sb->s_flags & MS_RDONLY)) {
625 if (new_rdonly)
626 fat_set_state(sb, 0, 0);
627 else
628 fat_set_state(sb, 1, 1);
629 }
630 return 0;
631 }
632
633 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
634 {
635 struct super_block *sb = dentry->d_sb;
636 struct msdos_sb_info *sbi = MSDOS_SB(sb);
637 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
638
639 /* If the count of free cluster is still unknown, counts it here. */
640 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
641 int err = fat_count_free_clusters(dentry->d_sb);
642 if (err)
643 return err;
644 }
645
646 buf->f_type = dentry->d_sb->s_magic;
647 buf->f_bsize = sbi->cluster_size;
648 buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
649 buf->f_bfree = sbi->free_clusters;
650 buf->f_bavail = sbi->free_clusters;
651 buf->f_fsid.val[0] = (u32)id;
652 buf->f_fsid.val[1] = (u32)(id >> 32);
653 buf->f_namelen =
654 (sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE;
655
656 return 0;
657 }
658
659 static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi,
660 struct inode *inode)
661 {
662 loff_t i_pos;
663 #if BITS_PER_LONG == 32
664 spin_lock(&sbi->inode_hash_lock);
665 #endif
666 i_pos = MSDOS_I(inode)->i_pos;
667 #if BITS_PER_LONG == 32
668 spin_unlock(&sbi->inode_hash_lock);
669 #endif
670 return i_pos;
671 }
672
673 static int __fat_write_inode(struct inode *inode, int wait)
674 {
675 struct super_block *sb = inode->i_sb;
676 struct msdos_sb_info *sbi = MSDOS_SB(sb);
677 struct buffer_head *bh;
678 struct msdos_dir_entry *raw_entry;
679 loff_t i_pos;
680 int err;
681
682 if (inode->i_ino == MSDOS_ROOT_INO)
683 return 0;
684
685 retry:
686 i_pos = fat_i_pos_read(sbi, inode);
687 if (!i_pos)
688 return 0;
689
690 bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits);
691 if (!bh) {
692 fat_msg(sb, KERN_ERR, "unable to read inode block "
693 "for updating (i_pos %lld)", i_pos);
694 return -EIO;
695 }
696 spin_lock(&sbi->inode_hash_lock);
697 if (i_pos != MSDOS_I(inode)->i_pos) {
698 spin_unlock(&sbi->inode_hash_lock);
699 brelse(bh);
700 goto retry;
701 }
702
703 raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
704 [i_pos & (sbi->dir_per_block - 1)];
705 if (S_ISDIR(inode->i_mode))
706 raw_entry->size = 0;
707 else
708 raw_entry->size = cpu_to_le32(inode->i_size);
709 raw_entry->attr = fat_make_attrs(inode);
710 fat_set_start(raw_entry, MSDOS_I(inode)->i_logstart);
711 fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
712 &raw_entry->date, NULL);
713 if (sbi->options.isvfat) {
714 __le16 atime;
715 fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime,
716 &raw_entry->cdate, &raw_entry->ctime_cs);
717 fat_time_unix2fat(sbi, &inode->i_atime, &atime,
718 &raw_entry->adate, NULL);
719 }
720 spin_unlock(&sbi->inode_hash_lock);
721 mark_buffer_dirty(bh);
722 err = 0;
723 if (wait)
724 err = sync_dirty_buffer(bh);
725 brelse(bh);
726 return err;
727 }
728
729 static int fat_write_inode(struct inode *inode, struct writeback_control *wbc)
730 {
731 int err;
732
733 if (inode->i_ino == MSDOS_FSINFO_INO) {
734 struct super_block *sb = inode->i_sb;
735
736 mutex_lock(&MSDOS_SB(sb)->s_lock);
737 err = fat_clusters_flush(sb);
738 mutex_unlock(&MSDOS_SB(sb)->s_lock);
739 } else
740 err = __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
741
742 return err;
743 }
744
745 int fat_sync_inode(struct inode *inode)
746 {
747 return __fat_write_inode(inode, 1);
748 }
749
750 EXPORT_SYMBOL_GPL(fat_sync_inode);
751
752 static int fat_show_options(struct seq_file *m, struct dentry *root);
753 static const struct super_operations fat_sops = {
754 .alloc_inode = fat_alloc_inode,
755 .destroy_inode = fat_destroy_inode,
756 .write_inode = fat_write_inode,
757 .evict_inode = fat_evict_inode,
758 .put_super = fat_put_super,
759 .statfs = fat_statfs,
760 .remount_fs = fat_remount,
761
762 .show_options = fat_show_options,
763 };
764
765 static const struct export_operations fat_export_ops = {
766 .fh_to_dentry = fat_fh_to_dentry,
767 .fh_to_parent = fat_fh_to_parent,
768 .get_parent = fat_get_parent,
769 };
770
771 static int fat_show_options(struct seq_file *m, struct dentry *root)
772 {
773 struct msdos_sb_info *sbi = MSDOS_SB(root->d_sb);
774 struct fat_mount_options *opts = &sbi->options;
775 int isvfat = opts->isvfat;
776
777 if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
778 seq_printf(m, ",uid=%u",
779 from_kuid_munged(&init_user_ns, opts->fs_uid));
780 if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
781 seq_printf(m, ",gid=%u",
782 from_kgid_munged(&init_user_ns, 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 /* strip "cp" prefix from displayed option */
789 seq_printf(m, ",codepage=%s", &sbi->nls_disk->charset[2]);
790 if (isvfat) {
791 if (sbi->nls_io)
792 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
793
794 switch (opts->shortname) {
795 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
796 seq_puts(m, ",shortname=win95");
797 break;
798 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
799 seq_puts(m, ",shortname=winnt");
800 break;
801 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
802 seq_puts(m, ",shortname=mixed");
803 break;
804 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
805 seq_puts(m, ",shortname=lower");
806 break;
807 default:
808 seq_puts(m, ",shortname=unknown");
809 break;
810 }
811 }
812 if (opts->name_check != 'n')
813 seq_printf(m, ",check=%c", opts->name_check);
814 if (opts->usefree)
815 seq_puts(m, ",usefree");
816 if (opts->quiet)
817 seq_puts(m, ",quiet");
818 if (opts->nfs)
819 seq_puts(m, ",nfs");
820 if (opts->showexec)
821 seq_puts(m, ",showexec");
822 if (opts->sys_immutable)
823 seq_puts(m, ",sys_immutable");
824 if (!isvfat) {
825 if (opts->dotsOK)
826 seq_puts(m, ",dotsOK=yes");
827 if (opts->nocase)
828 seq_puts(m, ",nocase");
829 } else {
830 if (opts->utf8)
831 seq_puts(m, ",utf8");
832 if (opts->unicode_xlate)
833 seq_puts(m, ",uni_xlate");
834 if (!opts->numtail)
835 seq_puts(m, ",nonumtail");
836 if (opts->rodir)
837 seq_puts(m, ",rodir");
838 }
839 if (opts->flush)
840 seq_puts(m, ",flush");
841 if (opts->tz_set) {
842 if (opts->time_offset)
843 seq_printf(m, ",time_offset=%d", opts->time_offset);
844 else
845 seq_puts(m, ",tz=UTC");
846 }
847 if (opts->errors == FAT_ERRORS_CONT)
848 seq_puts(m, ",errors=continue");
849 else if (opts->errors == FAT_ERRORS_PANIC)
850 seq_puts(m, ",errors=panic");
851 else
852 seq_puts(m, ",errors=remount-ro");
853 if (opts->discard)
854 seq_puts(m, ",discard");
855
856 return 0;
857 }
858
859 enum {
860 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
861 Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
862 Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
863 Opt_immutable, Opt_dots, Opt_nodots,
864 Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
865 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
866 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
867 Opt_obsolete, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
868 Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_time_offset,
869 Opt_err,
870 };
871
872 static const match_table_t fat_tokens = {
873 {Opt_check_r, "check=relaxed"},
874 {Opt_check_s, "check=strict"},
875 {Opt_check_n, "check=normal"},
876 {Opt_check_r, "check=r"},
877 {Opt_check_s, "check=s"},
878 {Opt_check_n, "check=n"},
879 {Opt_uid, "uid=%u"},
880 {Opt_gid, "gid=%u"},
881 {Opt_umask, "umask=%o"},
882 {Opt_dmask, "dmask=%o"},
883 {Opt_fmask, "fmask=%o"},
884 {Opt_allow_utime, "allow_utime=%o"},
885 {Opt_codepage, "codepage=%u"},
886 {Opt_usefree, "usefree"},
887 {Opt_nocase, "nocase"},
888 {Opt_quiet, "quiet"},
889 {Opt_showexec, "showexec"},
890 {Opt_debug, "debug"},
891 {Opt_immutable, "sys_immutable"},
892 {Opt_flush, "flush"},
893 {Opt_tz_utc, "tz=UTC"},
894 {Opt_time_offset, "time_offset=%d"},
895 {Opt_err_cont, "errors=continue"},
896 {Opt_err_panic, "errors=panic"},
897 {Opt_err_ro, "errors=remount-ro"},
898 {Opt_discard, "discard"},
899 {Opt_nfs, "nfs"},
900 {Opt_obsolete, "conv=binary"},
901 {Opt_obsolete, "conv=text"},
902 {Opt_obsolete, "conv=auto"},
903 {Opt_obsolete, "conv=b"},
904 {Opt_obsolete, "conv=t"},
905 {Opt_obsolete, "conv=a"},
906 {Opt_obsolete, "fat=%u"},
907 {Opt_obsolete, "blocksize=%u"},
908 {Opt_obsolete, "cvf_format=%20s"},
909 {Opt_obsolete, "cvf_options=%100s"},
910 {Opt_obsolete, "posix"},
911 {Opt_err, NULL},
912 };
913 static const match_table_t msdos_tokens = {
914 {Opt_nodots, "nodots"},
915 {Opt_nodots, "dotsOK=no"},
916 {Opt_dots, "dots"},
917 {Opt_dots, "dotsOK=yes"},
918 {Opt_err, NULL}
919 };
920 static const match_table_t vfat_tokens = {
921 {Opt_charset, "iocharset=%s"},
922 {Opt_shortname_lower, "shortname=lower"},
923 {Opt_shortname_win95, "shortname=win95"},
924 {Opt_shortname_winnt, "shortname=winnt"},
925 {Opt_shortname_mixed, "shortname=mixed"},
926 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */
927 {Opt_utf8_no, "utf8=no"},
928 {Opt_utf8_no, "utf8=false"},
929 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */
930 {Opt_utf8_yes, "utf8=yes"},
931 {Opt_utf8_yes, "utf8=true"},
932 {Opt_utf8_yes, "utf8"},
933 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */
934 {Opt_uni_xl_no, "uni_xlate=no"},
935 {Opt_uni_xl_no, "uni_xlate=false"},
936 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */
937 {Opt_uni_xl_yes, "uni_xlate=yes"},
938 {Opt_uni_xl_yes, "uni_xlate=true"},
939 {Opt_uni_xl_yes, "uni_xlate"},
940 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */
941 {Opt_nonumtail_no, "nonumtail=no"},
942 {Opt_nonumtail_no, "nonumtail=false"},
943 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */
944 {Opt_nonumtail_yes, "nonumtail=yes"},
945 {Opt_nonumtail_yes, "nonumtail=true"},
946 {Opt_nonumtail_yes, "nonumtail"},
947 {Opt_rodir, "rodir"},
948 {Opt_err, NULL}
949 };
950
951 static int parse_options(struct super_block *sb, char *options, int is_vfat,
952 int silent, int *debug, struct fat_mount_options *opts)
953 {
954 char *p;
955 substring_t args[MAX_OPT_ARGS];
956 int option;
957 char *iocharset;
958
959 opts->isvfat = is_vfat;
960
961 opts->fs_uid = current_uid();
962 opts->fs_gid = current_gid();
963 opts->fs_fmask = opts->fs_dmask = current_umask();
964 opts->allow_utime = -1;
965 opts->codepage = fat_default_codepage;
966 opts->iocharset = fat_default_iocharset;
967 if (is_vfat) {
968 opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95;
969 opts->rodir = 0;
970 } else {
971 opts->shortname = 0;
972 opts->rodir = 1;
973 }
974 opts->name_check = 'n';
975 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0;
976 opts->utf8 = opts->unicode_xlate = 0;
977 opts->numtail = 1;
978 opts->usefree = opts->nocase = 0;
979 opts->tz_set = 0;
980 opts->nfs = 0;
981 opts->errors = FAT_ERRORS_RO;
982 *debug = 0;
983
984 if (!options)
985 goto out;
986
987 while ((p = strsep(&options, ",")) != NULL) {
988 int token;
989 if (!*p)
990 continue;
991
992 token = match_token(p, fat_tokens, args);
993 if (token == Opt_err) {
994 if (is_vfat)
995 token = match_token(p, vfat_tokens, args);
996 else
997 token = match_token(p, msdos_tokens, args);
998 }
999 switch (token) {
1000 case Opt_check_s:
1001 opts->name_check = 's';
1002 break;
1003 case Opt_check_r:
1004 opts->name_check = 'r';
1005 break;
1006 case Opt_check_n:
1007 opts->name_check = 'n';
1008 break;
1009 case Opt_usefree:
1010 opts->usefree = 1;
1011 break;
1012 case Opt_nocase:
1013 if (!is_vfat)
1014 opts->nocase = 1;
1015 else {
1016 /* for backward compatibility */
1017 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1018 | VFAT_SFN_CREATE_WIN95;
1019 }
1020 break;
1021 case Opt_quiet:
1022 opts->quiet = 1;
1023 break;
1024 case Opt_showexec:
1025 opts->showexec = 1;
1026 break;
1027 case Opt_debug:
1028 *debug = 1;
1029 break;
1030 case Opt_immutable:
1031 opts->sys_immutable = 1;
1032 break;
1033 case Opt_uid:
1034 if (match_int(&args[0], &option))
1035 return -EINVAL;
1036 opts->fs_uid = make_kuid(current_user_ns(), option);
1037 if (!uid_valid(opts->fs_uid))
1038 return -EINVAL;
1039 break;
1040 case Opt_gid:
1041 if (match_int(&args[0], &option))
1042 return -EINVAL;
1043 opts->fs_gid = make_kgid(current_user_ns(), option);
1044 if (!gid_valid(opts->fs_gid))
1045 return -EINVAL;
1046 break;
1047 case Opt_umask:
1048 if (match_octal(&args[0], &option))
1049 return -EINVAL;
1050 opts->fs_fmask = opts->fs_dmask = option;
1051 break;
1052 case Opt_dmask:
1053 if (match_octal(&args[0], &option))
1054 return -EINVAL;
1055 opts->fs_dmask = option;
1056 break;
1057 case Opt_fmask:
1058 if (match_octal(&args[0], &option))
1059 return -EINVAL;
1060 opts->fs_fmask = option;
1061 break;
1062 case Opt_allow_utime:
1063 if (match_octal(&args[0], &option))
1064 return -EINVAL;
1065 opts->allow_utime = option & (S_IWGRP | S_IWOTH);
1066 break;
1067 case Opt_codepage:
1068 if (match_int(&args[0], &option))
1069 return -EINVAL;
1070 opts->codepage = option;
1071 break;
1072 case Opt_flush:
1073 opts->flush = 1;
1074 break;
1075 case Opt_time_offset:
1076 if (match_int(&args[0], &option))
1077 return -EINVAL;
1078 if (option < -12 * 60 || option > 12 * 60)
1079 return -EINVAL;
1080 opts->tz_set = 1;
1081 opts->time_offset = option;
1082 break;
1083 case Opt_tz_utc:
1084 opts->tz_set = 1;
1085 opts->time_offset = 0;
1086 break;
1087 case Opt_err_cont:
1088 opts->errors = FAT_ERRORS_CONT;
1089 break;
1090 case Opt_err_panic:
1091 opts->errors = FAT_ERRORS_PANIC;
1092 break;
1093 case Opt_err_ro:
1094 opts->errors = FAT_ERRORS_RO;
1095 break;
1096
1097 /* msdos specific */
1098 case Opt_dots:
1099 opts->dotsOK = 1;
1100 break;
1101 case Opt_nodots:
1102 opts->dotsOK = 0;
1103 break;
1104
1105 /* vfat specific */
1106 case Opt_charset:
1107 if (opts->iocharset != fat_default_iocharset)
1108 kfree(opts->iocharset);
1109 iocharset = match_strdup(&args[0]);
1110 if (!iocharset)
1111 return -ENOMEM;
1112 opts->iocharset = iocharset;
1113 break;
1114 case Opt_shortname_lower:
1115 opts->shortname = VFAT_SFN_DISPLAY_LOWER
1116 | VFAT_SFN_CREATE_WIN95;
1117 break;
1118 case Opt_shortname_win95:
1119 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1120 | VFAT_SFN_CREATE_WIN95;
1121 break;
1122 case Opt_shortname_winnt:
1123 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1124 | VFAT_SFN_CREATE_WINNT;
1125 break;
1126 case Opt_shortname_mixed:
1127 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1128 | VFAT_SFN_CREATE_WIN95;
1129 break;
1130 case Opt_utf8_no: /* 0 or no or false */
1131 opts->utf8 = 0;
1132 break;
1133 case Opt_utf8_yes: /* empty or 1 or yes or true */
1134 opts->utf8 = 1;
1135 break;
1136 case Opt_uni_xl_no: /* 0 or no or false */
1137 opts->unicode_xlate = 0;
1138 break;
1139 case Opt_uni_xl_yes: /* empty or 1 or yes or true */
1140 opts->unicode_xlate = 1;
1141 break;
1142 case Opt_nonumtail_no: /* 0 or no or false */
1143 opts->numtail = 1; /* negated option */
1144 break;
1145 case Opt_nonumtail_yes: /* empty or 1 or yes or true */
1146 opts->numtail = 0; /* negated option */
1147 break;
1148 case Opt_rodir:
1149 opts->rodir = 1;
1150 break;
1151 case Opt_discard:
1152 opts->discard = 1;
1153 break;
1154 case Opt_nfs:
1155 opts->nfs = 1;
1156 break;
1157
1158 /* obsolete mount options */
1159 case Opt_obsolete:
1160 fat_msg(sb, KERN_INFO, "\"%s\" option is obsolete, "
1161 "not supported now", p);
1162 break;
1163 /* unknown option */
1164 default:
1165 if (!silent) {
1166 fat_msg(sb, KERN_ERR,
1167 "Unrecognized mount option \"%s\" "
1168 "or missing value", p);
1169 }
1170 return -EINVAL;
1171 }
1172 }
1173
1174 out:
1175 /* UTF-8 doesn't provide FAT semantics */
1176 if (!strcmp(opts->iocharset, "utf8")) {
1177 fat_msg(sb, KERN_WARNING, "utf8 is not a recommended IO charset"
1178 " for FAT filesystems, filesystem will be "
1179 "case sensitive!");
1180 }
1181
1182 /* If user doesn't specify allow_utime, it's initialized from dmask. */
1183 if (opts->allow_utime == (unsigned short)-1)
1184 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1185 if (opts->unicode_xlate)
1186 opts->utf8 = 0;
1187
1188 return 0;
1189 }
1190
1191 static int fat_read_root(struct inode *inode)
1192 {
1193 struct super_block *sb = inode->i_sb;
1194 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1195 int error;
1196
1197 MSDOS_I(inode)->i_pos = 0;
1198 inode->i_uid = sbi->options.fs_uid;
1199 inode->i_gid = sbi->options.fs_gid;
1200 inode->i_version++;
1201 inode->i_generation = 0;
1202 inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
1203 inode->i_op = sbi->dir_ops;
1204 inode->i_fop = &fat_dir_operations;
1205 if (sbi->fat_bits == 32) {
1206 MSDOS_I(inode)->i_start = sbi->root_cluster;
1207 error = fat_calc_dir_size(inode);
1208 if (error < 0)
1209 return error;
1210 } else {
1211 MSDOS_I(inode)->i_start = 0;
1212 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1213 }
1214 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1215 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1216 MSDOS_I(inode)->i_logstart = 0;
1217 MSDOS_I(inode)->mmu_private = inode->i_size;
1218
1219 fat_save_attrs(inode, ATTR_DIR);
1220 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1221 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1222 set_nlink(inode, fat_subdirs(inode)+2);
1223
1224 return 0;
1225 }
1226
1227 /*
1228 * Read the super block of an MS-DOS FS.
1229 */
1230 int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
1231 void (*setup)(struct super_block *))
1232 {
1233 struct inode *root_inode = NULL, *fat_inode = NULL;
1234 struct inode *fsinfo_inode = NULL;
1235 struct buffer_head *bh;
1236 struct fat_boot_sector *b;
1237 struct msdos_sb_info *sbi;
1238 u16 logical_sector_size;
1239 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1240 int debug;
1241 unsigned int media;
1242 long error;
1243 char buf[50];
1244
1245 /*
1246 * GFP_KERNEL is ok here, because while we do hold the
1247 * supeblock lock, memory pressure can't call back into
1248 * the filesystem, since we're only just about to mount
1249 * it and have no inodes etc active!
1250 */
1251 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1252 if (!sbi)
1253 return -ENOMEM;
1254 sb->s_fs_info = sbi;
1255
1256 sb->s_flags |= MS_NODIRATIME;
1257 sb->s_magic = MSDOS_SUPER_MAGIC;
1258 sb->s_op = &fat_sops;
1259 sb->s_export_op = &fat_export_ops;
1260 ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
1261 DEFAULT_RATELIMIT_BURST);
1262
1263 error = parse_options(sb, data, isvfat, silent, &debug, &sbi->options);
1264 if (error)
1265 goto out_fail;
1266
1267 setup(sb); /* flavour-specific stuff that needs options */
1268
1269 error = -EIO;
1270 sb_min_blocksize(sb, 512);
1271 bh = sb_bread(sb, 0);
1272 if (bh == NULL) {
1273 fat_msg(sb, KERN_ERR, "unable to read boot sector");
1274 goto out_fail;
1275 }
1276
1277 b = (struct fat_boot_sector *) bh->b_data;
1278 if (!b->reserved) {
1279 if (!silent)
1280 fat_msg(sb, KERN_ERR, "bogus number of reserved sectors");
1281 brelse(bh);
1282 goto out_invalid;
1283 }
1284 if (!b->fats) {
1285 if (!silent)
1286 fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
1287 brelse(bh);
1288 goto out_invalid;
1289 }
1290
1291 /*
1292 * Earlier we checked here that b->secs_track and b->head are nonzero,
1293 * but it turns out valid FAT filesystems can have zero there.
1294 */
1295
1296 media = b->media;
1297 if (!fat_valid_media(media)) {
1298 if (!silent)
1299 fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
1300 media);
1301 brelse(bh);
1302 goto out_invalid;
1303 }
1304 logical_sector_size = get_unaligned_le16(&b->sector_size);
1305 if (!is_power_of_2(logical_sector_size)
1306 || (logical_sector_size < 512)
1307 || (logical_sector_size > 4096)) {
1308 if (!silent)
1309 fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
1310 logical_sector_size);
1311 brelse(bh);
1312 goto out_invalid;
1313 }
1314 sbi->sec_per_clus = b->sec_per_clus;
1315 if (!is_power_of_2(sbi->sec_per_clus)) {
1316 if (!silent)
1317 fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
1318 sbi->sec_per_clus);
1319 brelse(bh);
1320 goto out_invalid;
1321 }
1322
1323 if (logical_sector_size < sb->s_blocksize) {
1324 fat_msg(sb, KERN_ERR, "logical sector size too small for device"
1325 " (logical sector size = %u)", logical_sector_size);
1326 brelse(bh);
1327 goto out_fail;
1328 }
1329 if (logical_sector_size > sb->s_blocksize) {
1330 brelse(bh);
1331
1332 if (!sb_set_blocksize(sb, logical_sector_size)) {
1333 fat_msg(sb, KERN_ERR, "unable to set blocksize %u",
1334 logical_sector_size);
1335 goto out_fail;
1336 }
1337 bh = sb_bread(sb, 0);
1338 if (bh == NULL) {
1339 fat_msg(sb, KERN_ERR, "unable to read boot sector"
1340 " (logical sector size = %lu)",
1341 sb->s_blocksize);
1342 goto out_fail;
1343 }
1344 b = (struct fat_boot_sector *) bh->b_data;
1345 }
1346
1347 mutex_init(&sbi->s_lock);
1348 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1349 sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1350 sbi->fats = b->fats;
1351 sbi->fat_bits = 0; /* Don't know yet */
1352 sbi->fat_start = le16_to_cpu(b->reserved);
1353 sbi->fat_length = le16_to_cpu(b->fat_length);
1354 sbi->root_cluster = 0;
1355 sbi->free_clusters = -1; /* Don't know yet */
1356 sbi->free_clus_valid = 0;
1357 sbi->prev_free = FAT_START_ENT;
1358 sb->s_maxbytes = 0xffffffff;
1359
1360 if (!sbi->fat_length && b->fat32.length) {
1361 struct fat_boot_fsinfo *fsinfo;
1362 struct buffer_head *fsinfo_bh;
1363
1364 /* Must be FAT32 */
1365 sbi->fat_bits = 32;
1366 sbi->fat_length = le32_to_cpu(b->fat32.length);
1367 sbi->root_cluster = le32_to_cpu(b->fat32.root_cluster);
1368
1369 /* MC - if info_sector is 0, don't multiply by 0 */
1370 sbi->fsinfo_sector = le16_to_cpu(b->fat32.info_sector);
1371 if (sbi->fsinfo_sector == 0)
1372 sbi->fsinfo_sector = 1;
1373
1374 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1375 if (fsinfo_bh == NULL) {
1376 fat_msg(sb, KERN_ERR, "bread failed, FSINFO block"
1377 " (sector = %lu)", sbi->fsinfo_sector);
1378 brelse(bh);
1379 goto out_fail;
1380 }
1381
1382 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1383 if (!IS_FSINFO(fsinfo)) {
1384 fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: "
1385 "0x%08x, 0x%08x (sector = %lu)",
1386 le32_to_cpu(fsinfo->signature1),
1387 le32_to_cpu(fsinfo->signature2),
1388 sbi->fsinfo_sector);
1389 } else {
1390 if (sbi->options.usefree)
1391 sbi->free_clus_valid = 1;
1392 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1393 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1394 }
1395
1396 brelse(fsinfo_bh);
1397 }
1398
1399 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1400 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1401
1402 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1403 sbi->dir_entries = get_unaligned_le16(&b->dir_entries);
1404 if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1405 if (!silent)
1406 fat_msg(sb, KERN_ERR, "bogus directory-entries per block"
1407 " (%u)", sbi->dir_entries);
1408 brelse(bh);
1409 goto out_invalid;
1410 }
1411
1412 rootdir_sectors = sbi->dir_entries
1413 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1414 sbi->data_start = sbi->dir_start + rootdir_sectors;
1415 total_sectors = get_unaligned_le16(&b->sectors);
1416 if (total_sectors == 0)
1417 total_sectors = le32_to_cpu(b->total_sect);
1418
1419 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1420
1421 if (sbi->fat_bits != 32)
1422 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1423
1424 /* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
1425 if (sbi->fat_bits == 32)
1426 sbi->dirty = b->fat32.state & FAT_STATE_DIRTY;
1427 else /* fat 16 or 12 */
1428 sbi->dirty = b->fat16.state & FAT_STATE_DIRTY;
1429
1430 /* check that FAT table does not overflow */
1431 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1432 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1433 if (total_clusters > MAX_FAT(sb)) {
1434 if (!silent)
1435 fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
1436 total_clusters);
1437 brelse(bh);
1438 goto out_invalid;
1439 }
1440
1441 sbi->max_cluster = total_clusters + FAT_START_ENT;
1442 /* check the free_clusters, it's not necessarily correct */
1443 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1444 sbi->free_clusters = -1;
1445 /* check the prev_free, it's not necessarily correct */
1446 sbi->prev_free %= sbi->max_cluster;
1447 if (sbi->prev_free < FAT_START_ENT)
1448 sbi->prev_free = FAT_START_ENT;
1449
1450 brelse(bh);
1451
1452 /* set up enough so that it can read an inode */
1453 fat_hash_init(sb);
1454 dir_hash_init(sb);
1455 fat_ent_access_init(sb);
1456
1457 /*
1458 * The low byte of FAT's first entry must have same value with
1459 * media-field. But in real world, too many devices is
1460 * writing wrong value. So, removed that validity check.
1461 *
1462 * if (FAT_FIRST_ENT(sb, media) != first)
1463 */
1464
1465 error = -EINVAL;
1466 sprintf(buf, "cp%d", sbi->options.codepage);
1467 sbi->nls_disk = load_nls(buf);
1468 if (!sbi->nls_disk) {
1469 fat_msg(sb, KERN_ERR, "codepage %s not found", buf);
1470 goto out_fail;
1471 }
1472
1473 /* FIXME: utf8 is using iocharset for upper/lower conversion */
1474 if (sbi->options.isvfat) {
1475 sbi->nls_io = load_nls(sbi->options.iocharset);
1476 if (!sbi->nls_io) {
1477 fat_msg(sb, KERN_ERR, "IO charset %s not found",
1478 sbi->options.iocharset);
1479 goto out_fail;
1480 }
1481 }
1482
1483 error = -ENOMEM;
1484 fat_inode = new_inode(sb);
1485 if (!fat_inode)
1486 goto out_fail;
1487 MSDOS_I(fat_inode)->i_pos = 0;
1488 sbi->fat_inode = fat_inode;
1489
1490 fsinfo_inode = new_inode(sb);
1491 if (!fsinfo_inode)
1492 goto out_fail;
1493 fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
1494 sbi->fsinfo_inode = fsinfo_inode;
1495 insert_inode_hash(fsinfo_inode);
1496
1497 root_inode = new_inode(sb);
1498 if (!root_inode)
1499 goto out_fail;
1500 root_inode->i_ino = MSDOS_ROOT_INO;
1501 root_inode->i_version = 1;
1502 error = fat_read_root(root_inode);
1503 if (error < 0) {
1504 iput(root_inode);
1505 goto out_fail;
1506 }
1507 error = -ENOMEM;
1508 insert_inode_hash(root_inode);
1509 fat_attach(root_inode, 0);
1510 sb->s_root = d_make_root(root_inode);
1511 if (!sb->s_root) {
1512 fat_msg(sb, KERN_ERR, "get root inode failed");
1513 goto out_fail;
1514 }
1515
1516 if (sbi->options.discard) {
1517 struct request_queue *q = bdev_get_queue(sb->s_bdev);
1518 if (!blk_queue_discard(q))
1519 fat_msg(sb, KERN_WARNING,
1520 "mounting with \"discard\" option, but "
1521 "the device does not support discard");
1522 }
1523
1524 fat_set_state(sb, 1, 0);
1525 return 0;
1526
1527 out_invalid:
1528 error = -EINVAL;
1529 if (!silent)
1530 fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem");
1531
1532 out_fail:
1533 if (fsinfo_inode)
1534 iput(fsinfo_inode);
1535 if (fat_inode)
1536 iput(fat_inode);
1537 unload_nls(sbi->nls_io);
1538 unload_nls(sbi->nls_disk);
1539 if (sbi->options.iocharset != fat_default_iocharset)
1540 kfree(sbi->options.iocharset);
1541 sb->s_fs_info = NULL;
1542 kfree(sbi);
1543 return error;
1544 }
1545
1546 EXPORT_SYMBOL_GPL(fat_fill_super);
1547
1548 /*
1549 * helper function for fat_flush_inodes. This writes both the inode
1550 * and the file data blocks, waiting for in flight data blocks before
1551 * the start of the call. It does not wait for any io started
1552 * during the call
1553 */
1554 static int writeback_inode(struct inode *inode)
1555 {
1556
1557 int ret;
1558
1559 /* if we used wait=1, sync_inode_metadata waits for the io for the
1560 * inode to finish. So wait=0 is sent down to sync_inode_metadata
1561 * and filemap_fdatawrite is used for the data blocks
1562 */
1563 ret = sync_inode_metadata(inode, 0);
1564 if (!ret)
1565 ret = filemap_fdatawrite(inode->i_mapping);
1566 return ret;
1567 }
1568
1569 /*
1570 * write data and metadata corresponding to i1 and i2. The io is
1571 * started but we do not wait for any of it to finish.
1572 *
1573 * filemap_flush is used for the block device, so if there is a dirty
1574 * page for a block already in flight, we will not wait and start the
1575 * io over again
1576 */
1577 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1578 {
1579 int ret = 0;
1580 if (!MSDOS_SB(sb)->options.flush)
1581 return 0;
1582 if (i1)
1583 ret = writeback_inode(i1);
1584 if (!ret && i2)
1585 ret = writeback_inode(i2);
1586 if (!ret) {
1587 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
1588 ret = filemap_flush(mapping);
1589 }
1590 return ret;
1591 }
1592 EXPORT_SYMBOL_GPL(fat_flush_inodes);
1593
1594 static int __init init_fat_fs(void)
1595 {
1596 int err;
1597
1598 err = fat_cache_init();
1599 if (err)
1600 return err;
1601
1602 err = fat_init_inodecache();
1603 if (err)
1604 goto failed;
1605
1606 return 0;
1607
1608 failed:
1609 fat_cache_destroy();
1610 return err;
1611 }
1612
1613 static void __exit exit_fat_fs(void)
1614 {
1615 fat_cache_destroy();
1616 fat_destroy_inodecache();
1617 }
1618
1619 module_init(init_fat_fs)
1620 module_exit(exit_fat_fs)
1621
1622 MODULE_LICENSE("GPL");
Linux kernel - Deliverables
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