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14#include <linux/module.h>
15#include <linux/pagemap.h>
16#include <linux/mpage.h>
17#include <linux/vfs.h>
18#include <linux/seq_file.h>
19#include <linux/parser.h>
20#include <linux/uio.h>
21#include <linux/blkdev.h>
22#include <linux/backing-dev.h>
23#include <asm/unaligned.h>
24#include <linux/random.h>
25#include <linux/iversion.h>
26#include "fat.h"
27
28#ifndef CONFIG_FAT_DEFAULT_IOCHARSET
29
30#define CONFIG_FAT_DEFAULT_IOCHARSET ""
31#endif
32
33#define KB_IN_SECTORS 2
34
35
36#define FAT_DATE_MIN (0<<9 | 1<<5 | 1)
37#define FAT_DATE_MAX (127<<9 | 12<<5 | 31)
38#define FAT_TIME_MAX (23<<11 | 59<<5 | 29)
39
40
41
42
43
44struct fat_bios_param_block {
45 u16 fat_sector_size;
46 u8 fat_sec_per_clus;
47 u16 fat_reserved;
48 u8 fat_fats;
49 u16 fat_dir_entries;
50 u16 fat_sectors;
51 u16 fat_fat_length;
52 u32 fat_total_sect;
53
54 u8 fat16_state;
55 u32 fat16_vol_id;
56
57 u32 fat32_length;
58 u32 fat32_root_cluster;
59 u16 fat32_info_sector;
60 u8 fat32_state;
61 u32 fat32_vol_id;
62};
63
64static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
65static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
66
67static struct fat_floppy_defaults {
68 unsigned nr_sectors;
69 unsigned sec_per_clus;
70 unsigned dir_entries;
71 unsigned media;
72 unsigned fat_length;
73} floppy_defaults[] = {
74{
75 .nr_sectors = 160 * KB_IN_SECTORS,
76 .sec_per_clus = 1,
77 .dir_entries = 64,
78 .media = 0xFE,
79 .fat_length = 1,
80},
81{
82 .nr_sectors = 180 * KB_IN_SECTORS,
83 .sec_per_clus = 1,
84 .dir_entries = 64,
85 .media = 0xFC,
86 .fat_length = 2,
87},
88{
89 .nr_sectors = 320 * KB_IN_SECTORS,
90 .sec_per_clus = 2,
91 .dir_entries = 112,
92 .media = 0xFF,
93 .fat_length = 1,
94},
95{
96 .nr_sectors = 360 * KB_IN_SECTORS,
97 .sec_per_clus = 2,
98 .dir_entries = 112,
99 .media = 0xFD,
100 .fat_length = 2,
101},
102};
103
104int fat_add_cluster(struct inode *inode)
105{
106 int err, cluster;
107
108 err = fat_alloc_clusters(inode, &cluster, 1);
109 if (err)
110 return err;
111
112
113 err = fat_chain_add(inode, cluster, 1);
114 if (err)
115 fat_free_clusters(inode, cluster);
116 return err;
117}
118
119static inline int __fat_get_block(struct inode *inode, sector_t iblock,
120 unsigned long *max_blocks,
121 struct buffer_head *bh_result, int create)
122{
123 struct super_block *sb = inode->i_sb;
124 struct msdos_sb_info *sbi = MSDOS_SB(sb);
125 unsigned long mapped_blocks;
126 sector_t phys, last_block;
127 int err, offset;
128
129 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create, false);
130 if (err)
131 return err;
132 if (phys) {
133 map_bh(bh_result, sb, phys);
134 *max_blocks = min(mapped_blocks, *max_blocks);
135 return 0;
136 }
137 if (!create)
138 return 0;
139
140 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
141 fat_fs_error(sb, "corrupted file size (i_pos %lld, %lld)",
142 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
143 return -EIO;
144 }
145
146 last_block = inode->i_blocks >> (sb->s_blocksize_bits - 9);
147 offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
148
149
150
151
152
153 if (!offset && !(iblock < last_block)) {
154
155 err = fat_add_cluster(inode);
156 if (err)
157 return err;
158 }
159
160 mapped_blocks = sbi->sec_per_clus - offset;
161
162 *max_blocks = min(mapped_blocks, *max_blocks);
163 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
164
165 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create, false);
166 if (err)
167 return err;
168 if (!phys) {
169 fat_fs_error(sb,
170 "invalid FAT chain (i_pos %lld, last_block %llu)",
171 MSDOS_I(inode)->i_pos,
172 (unsigned long long)last_block);
173 return -EIO;
174 }
175
176 BUG_ON(*max_blocks != mapped_blocks);
177 set_buffer_new(bh_result);
178 map_bh(bh_result, sb, phys);
179
180 return 0;
181}
182
183static int fat_get_block(struct inode *inode, sector_t iblock,
184 struct buffer_head *bh_result, int create)
185{
186 struct super_block *sb = inode->i_sb;
187 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
188 int err;
189
190 err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create);
191 if (err)
192 return err;
193 bh_result->b_size = max_blocks << sb->s_blocksize_bits;
194 return 0;
195}
196
197static int fat_writepage(struct page *page, struct writeback_control *wbc)
198{
199 return block_write_full_page(page, fat_get_block, wbc);
200}
201
202static int fat_writepages(struct address_space *mapping,
203 struct writeback_control *wbc)
204{
205 return mpage_writepages(mapping, wbc, fat_get_block);
206}
207
208static int fat_readpage(struct file *file, struct page *page)
209{
210 return mpage_readpage(page, fat_get_block);
211}
212
213static void fat_readahead(struct readahead_control *rac)
214{
215 mpage_readahead(rac, fat_get_block);
216}
217
218static void fat_write_failed(struct address_space *mapping, loff_t to)
219{
220 struct inode *inode = mapping->host;
221
222 if (to > inode->i_size) {
223 truncate_pagecache(inode, inode->i_size);
224 fat_truncate_blocks(inode, inode->i_size);
225 }
226}
227
228static int fat_write_begin(struct file *file, struct address_space *mapping,
229 loff_t pos, unsigned len, unsigned flags,
230 struct page **pagep, void **fsdata)
231{
232 int err;
233
234 *pagep = NULL;
235 err = cont_write_begin(file, mapping, pos, len, flags,
236 pagep, fsdata, fat_get_block,
237 &MSDOS_I(mapping->host)->mmu_private);
238 if (err < 0)
239 fat_write_failed(mapping, pos + len);
240 return err;
241}
242
243static int fat_write_end(struct file *file, struct address_space *mapping,
244 loff_t pos, unsigned len, unsigned copied,
245 struct page *pagep, void *fsdata)
246{
247 struct inode *inode = mapping->host;
248 int err;
249 err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
250 if (err < len)
251 fat_write_failed(mapping, pos + len);
252 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
253 fat_truncate_time(inode, NULL, S_CTIME|S_MTIME);
254 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
255 mark_inode_dirty(inode);
256 }
257 return err;
258}
259
260static ssize_t fat_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
261{
262 struct file *file = iocb->ki_filp;
263 struct address_space *mapping = file->f_mapping;
264 struct inode *inode = mapping->host;
265 size_t count = iov_iter_count(iter);
266 loff_t offset = iocb->ki_pos;
267 ssize_t ret;
268
269 if (iov_iter_rw(iter) == WRITE) {
270
271
272
273
274
275
276
277
278
279 loff_t size = offset + count;
280 if (MSDOS_I(inode)->mmu_private < size)
281 return 0;
282 }
283
284
285
286
287
288 ret = blockdev_direct_IO(iocb, inode, iter, fat_get_block);
289 if (ret < 0 && iov_iter_rw(iter) == WRITE)
290 fat_write_failed(mapping, offset + count);
291
292 return ret;
293}
294
295static int fat_get_block_bmap(struct inode *inode, sector_t iblock,
296 struct buffer_head *bh_result, int create)
297{
298 struct super_block *sb = inode->i_sb;
299 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
300 int err;
301 sector_t bmap;
302 unsigned long mapped_blocks;
303
304 BUG_ON(create != 0);
305
306 err = fat_bmap(inode, iblock, &bmap, &mapped_blocks, create, true);
307 if (err)
308 return err;
309
310 if (bmap) {
311 map_bh(bh_result, sb, bmap);
312 max_blocks = min(mapped_blocks, max_blocks);
313 }
314
315 bh_result->b_size = max_blocks << sb->s_blocksize_bits;
316
317 return 0;
318}
319
320static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
321{
322 sector_t blocknr;
323
324
325 down_read(&MSDOS_I(mapping->host)->truncate_lock);
326 blocknr = generic_block_bmap(mapping, block, fat_get_block_bmap);
327 up_read(&MSDOS_I(mapping->host)->truncate_lock);
328
329 return blocknr;
330}
331
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336
337
338
339int fat_block_truncate_page(struct inode *inode, loff_t from)
340{
341 return block_truncate_page(inode->i_mapping, from, fat_get_block);
342}
343
344static const struct address_space_operations fat_aops = {
345 .set_page_dirty = __set_page_dirty_buffers,
346 .readpage = fat_readpage,
347 .readahead = fat_readahead,
348 .writepage = fat_writepage,
349 .writepages = fat_writepages,
350 .write_begin = fat_write_begin,
351 .write_end = fat_write_end,
352 .direct_IO = fat_direct_IO,
353 .bmap = _fat_bmap
354};
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379
380static void fat_hash_init(struct super_block *sb)
381{
382 struct msdos_sb_info *sbi = MSDOS_SB(sb);
383 int i;
384
385 spin_lock_init(&sbi->inode_hash_lock);
386 for (i = 0; i < FAT_HASH_SIZE; i++)
387 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
388}
389
390static inline unsigned long fat_hash(loff_t i_pos)
391{
392 return hash_32(i_pos, FAT_HASH_BITS);
393}
394
395static void dir_hash_init(struct super_block *sb)
396{
397 struct msdos_sb_info *sbi = MSDOS_SB(sb);
398 int i;
399
400 spin_lock_init(&sbi->dir_hash_lock);
401 for (i = 0; i < FAT_HASH_SIZE; i++)
402 INIT_HLIST_HEAD(&sbi->dir_hashtable[i]);
403}
404
405void fat_attach(struct inode *inode, loff_t i_pos)
406{
407 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
408
409 if (inode->i_ino != MSDOS_ROOT_INO) {
410 struct hlist_head *head = sbi->inode_hashtable
411 + fat_hash(i_pos);
412
413 spin_lock(&sbi->inode_hash_lock);
414 MSDOS_I(inode)->i_pos = i_pos;
415 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
416 spin_unlock(&sbi->inode_hash_lock);
417 }
418
419
420
421
422
423 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
424 struct hlist_head *d_head = sbi->dir_hashtable;
425 d_head += fat_dir_hash(MSDOS_I(inode)->i_logstart);
426
427 spin_lock(&sbi->dir_hash_lock);
428 hlist_add_head(&MSDOS_I(inode)->i_dir_hash, d_head);
429 spin_unlock(&sbi->dir_hash_lock);
430 }
431}
432EXPORT_SYMBOL_GPL(fat_attach);
433
434void fat_detach(struct inode *inode)
435{
436 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
437 spin_lock(&sbi->inode_hash_lock);
438 MSDOS_I(inode)->i_pos = 0;
439 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
440 spin_unlock(&sbi->inode_hash_lock);
441
442 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
443 spin_lock(&sbi->dir_hash_lock);
444 hlist_del_init(&MSDOS_I(inode)->i_dir_hash);
445 spin_unlock(&sbi->dir_hash_lock);
446 }
447}
448EXPORT_SYMBOL_GPL(fat_detach);
449
450struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
451{
452 struct msdos_sb_info *sbi = MSDOS_SB(sb);
453 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
454 struct msdos_inode_info *i;
455 struct inode *inode = NULL;
456
457 spin_lock(&sbi->inode_hash_lock);
458 hlist_for_each_entry(i, head, i_fat_hash) {
459 BUG_ON(i->vfs_inode.i_sb != sb);
460 if (i->i_pos != i_pos)
461 continue;
462 inode = igrab(&i->vfs_inode);
463 if (inode)
464 break;
465 }
466 spin_unlock(&sbi->inode_hash_lock);
467 return inode;
468}
469
470static int is_exec(unsigned char *extension)
471{
472 unsigned char exe_extensions[] = "EXECOMBAT", *walk;
473
474 for (walk = exe_extensions; *walk; walk += 3)
475 if (!strncmp(extension, walk, 3))
476 return 1;
477 return 0;
478}
479
480static int fat_calc_dir_size(struct inode *inode)
481{
482 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
483 int ret, fclus, dclus;
484
485 inode->i_size = 0;
486 if (MSDOS_I(inode)->i_start == 0)
487 return 0;
488
489 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
490 if (ret < 0)
491 return ret;
492 inode->i_size = (fclus + 1) << sbi->cluster_bits;
493
494 return 0;
495}
496
497static int fat_validate_dir(struct inode *dir)
498{
499 struct super_block *sb = dir->i_sb;
500
501 if (dir->i_nlink < 2) {
502
503 fat_fs_error(sb, "corrupted directory (invalid entries)");
504 return -EIO;
505 }
506 if (MSDOS_I(dir)->i_start == 0 ||
507 MSDOS_I(dir)->i_start == MSDOS_SB(sb)->root_cluster) {
508
509 fat_fs_error(sb, "corrupted directory (invalid i_start)");
510 return -EIO;
511 }
512 return 0;
513}
514
515
516int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
517{
518 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
519 int error;
520
521 MSDOS_I(inode)->i_pos = 0;
522 inode->i_uid = sbi->options.fs_uid;
523 inode->i_gid = sbi->options.fs_gid;
524 inode_inc_iversion(inode);
525 inode->i_generation = prandom_u32();
526
527 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
528 inode->i_generation &= ~1;
529 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
530 inode->i_op = sbi->dir_ops;
531 inode->i_fop = &fat_dir_operations;
532
533 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
534 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
535 error = fat_calc_dir_size(inode);
536 if (error < 0)
537 return error;
538 MSDOS_I(inode)->mmu_private = inode->i_size;
539
540 set_nlink(inode, fat_subdirs(inode));
541
542 error = fat_validate_dir(inode);
543 if (error < 0)
544 return error;
545 } else {
546 inode->i_generation |= 1;
547 inode->i_mode = fat_make_mode(sbi, de->attr,
548 ((sbi->options.showexec && !is_exec(de->name + 8))
549 ? S_IRUGO|S_IWUGO : S_IRWXUGO));
550 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
551
552 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
553 inode->i_size = le32_to_cpu(de->size);
554 inode->i_op = &fat_file_inode_operations;
555 inode->i_fop = &fat_file_operations;
556 inode->i_mapping->a_ops = &fat_aops;
557 MSDOS_I(inode)->mmu_private = inode->i_size;
558 }
559 if (de->attr & ATTR_SYS) {
560 if (sbi->options.sys_immutable)
561 inode->i_flags |= S_IMMUTABLE;
562 }
563 fat_save_attrs(inode, de->attr);
564
565 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
566 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
567
568 fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0);
569 if (sbi->options.isvfat) {
570 fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime,
571 de->cdate, de->ctime_cs);
572 fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
573 } else
574 fat_truncate_time(inode, &inode->i_mtime, S_ATIME|S_CTIME);
575
576 return 0;
577}
578
579static inline void fat_lock_build_inode(struct msdos_sb_info *sbi)
580{
581 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
582 mutex_lock(&sbi->nfs_build_inode_lock);
583}
584
585static inline void fat_unlock_build_inode(struct msdos_sb_info *sbi)
586{
587 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
588 mutex_unlock(&sbi->nfs_build_inode_lock);
589}
590
591struct inode *fat_build_inode(struct super_block *sb,
592 struct msdos_dir_entry *de, loff_t i_pos)
593{
594 struct inode *inode;
595 int err;
596
597 fat_lock_build_inode(MSDOS_SB(sb));
598 inode = fat_iget(sb, i_pos);
599 if (inode)
600 goto out;
601 inode = new_inode(sb);
602 if (!inode) {
603 inode = ERR_PTR(-ENOMEM);
604 goto out;
605 }
606 inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
607 inode_set_iversion(inode, 1);
608 err = fat_fill_inode(inode, de);
609 if (err) {
610 iput(inode);
611 inode = ERR_PTR(err);
612 goto out;
613 }
614 fat_attach(inode, i_pos);
615 insert_inode_hash(inode);
616out:
617 fat_unlock_build_inode(MSDOS_SB(sb));
618 return inode;
619}
620
621EXPORT_SYMBOL_GPL(fat_build_inode);
622
623static int __fat_write_inode(struct inode *inode, int wait);
624
625static void fat_free_eofblocks(struct inode *inode)
626{
627
628 if ((inode->i_blocks << 9) >
629 round_up(MSDOS_I(inode)->mmu_private,
630 MSDOS_SB(inode->i_sb)->cluster_size)) {
631 int err;
632
633 fat_truncate_blocks(inode, MSDOS_I(inode)->mmu_private);
634
635
636
637
638
639
640 err = __fat_write_inode(inode, inode_needs_sync(inode));
641 if (err) {
642 fat_msg(inode->i_sb, KERN_WARNING, "Failed to "
643 "update on disk inode for unused "
644 "fallocated blocks, inode could be "
645 "corrupted. Please run fsck");
646 }
647
648 }
649}
650
651static void fat_evict_inode(struct inode *inode)
652{
653 truncate_inode_pages_final(&inode->i_data);
654 if (!inode->i_nlink) {
655 inode->i_size = 0;
656 fat_truncate_blocks(inode, 0);
657 } else
658 fat_free_eofblocks(inode);
659
660 invalidate_inode_buffers(inode);
661 clear_inode(inode);
662 fat_cache_inval_inode(inode);
663 fat_detach(inode);
664}
665
666static void fat_set_state(struct super_block *sb,
667 unsigned int set, unsigned int force)
668{
669 struct buffer_head *bh;
670 struct fat_boot_sector *b;
671 struct msdos_sb_info *sbi = MSDOS_SB(sb);
672
673
674 if (sb_rdonly(sb) && !force)
675 return;
676
677
678 if (sbi->dirty) {
679
680 if (set)
681 fat_msg(sb, KERN_WARNING, "Volume was not properly "
682 "unmounted. Some data may be corrupt. "
683 "Please run fsck.");
684 return;
685 }
686
687 bh = sb_bread(sb, 0);
688 if (bh == NULL) {
689 fat_msg(sb, KERN_ERR, "unable to read boot sector "
690 "to mark fs as dirty");
691 return;
692 }
693
694 b = (struct fat_boot_sector *) bh->b_data;
695
696 if (is_fat32(sbi)) {
697 if (set)
698 b->fat32.state |= FAT_STATE_DIRTY;
699 else
700 b->fat32.state &= ~FAT_STATE_DIRTY;
701 } else {
702 if (set)
703 b->fat16.state |= FAT_STATE_DIRTY;
704 else
705 b->fat16.state &= ~FAT_STATE_DIRTY;
706 }
707
708 mark_buffer_dirty(bh);
709 sync_dirty_buffer(bh);
710 brelse(bh);
711}
712
713static void fat_reset_iocharset(struct fat_mount_options *opts)
714{
715 if (opts->iocharset != fat_default_iocharset) {
716
717 kfree(opts->iocharset);
718 opts->iocharset = fat_default_iocharset;
719 }
720}
721
722static void delayed_free(struct rcu_head *p)
723{
724 struct msdos_sb_info *sbi = container_of(p, struct msdos_sb_info, rcu);
725 unload_nls(sbi->nls_disk);
726 unload_nls(sbi->nls_io);
727 fat_reset_iocharset(&sbi->options);
728 kfree(sbi);
729}
730
731static void fat_put_super(struct super_block *sb)
732{
733 struct msdos_sb_info *sbi = MSDOS_SB(sb);
734
735 fat_set_state(sb, 0, 0);
736
737 iput(sbi->fsinfo_inode);
738 iput(sbi->fat_inode);
739
740 call_rcu(&sbi->rcu, delayed_free);
741}
742
743static struct kmem_cache *fat_inode_cachep;
744
745static struct inode *fat_alloc_inode(struct super_block *sb)
746{
747 struct msdos_inode_info *ei;
748 ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
749 if (!ei)
750 return NULL;
751
752 init_rwsem(&ei->truncate_lock);
753
754 ei->mmu_private = 0;
755 ei->i_start = 0;
756 ei->i_logstart = 0;
757 ei->i_attrs = 0;
758 ei->i_pos = 0;
759
760 return &ei->vfs_inode;
761}
762
763static void fat_free_inode(struct inode *inode)
764{
765 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
766}
767
768static void init_once(void *foo)
769{
770 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
771
772 spin_lock_init(&ei->cache_lru_lock);
773 ei->nr_caches = 0;
774 ei->cache_valid_id = FAT_CACHE_VALID + 1;
775 INIT_LIST_HEAD(&ei->cache_lru);
776 INIT_HLIST_NODE(&ei->i_fat_hash);
777 INIT_HLIST_NODE(&ei->i_dir_hash);
778 inode_init_once(&ei->vfs_inode);
779}
780
781static int __init fat_init_inodecache(void)
782{
783 fat_inode_cachep = kmem_cache_create("fat_inode_cache",
784 sizeof(struct msdos_inode_info),
785 0, (SLAB_RECLAIM_ACCOUNT|
786 SLAB_MEM_SPREAD|SLAB_ACCOUNT),
787 init_once);
788 if (fat_inode_cachep == NULL)
789 return -ENOMEM;
790 return 0;
791}
792
793static void __exit fat_destroy_inodecache(void)
794{
795
796
797
798
799 rcu_barrier();
800 kmem_cache_destroy(fat_inode_cachep);
801}
802
803static int fat_remount(struct super_block *sb, int *flags, char *data)
804{
805 bool new_rdonly;
806 struct msdos_sb_info *sbi = MSDOS_SB(sb);
807 *flags |= SB_NODIRATIME | (sbi->options.isvfat ? 0 : SB_NOATIME);
808
809 sync_filesystem(sb);
810
811
812 new_rdonly = *flags & SB_RDONLY;
813 if (new_rdonly != sb_rdonly(sb)) {
814 if (new_rdonly)
815 fat_set_state(sb, 0, 0);
816 else
817 fat_set_state(sb, 1, 1);
818 }
819 return 0;
820}
821
822static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
823{
824 struct super_block *sb = dentry->d_sb;
825 struct msdos_sb_info *sbi = MSDOS_SB(sb);
826 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
827
828
829 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
830 int err = fat_count_free_clusters(dentry->d_sb);
831 if (err)
832 return err;
833 }
834
835 buf->f_type = dentry->d_sb->s_magic;
836 buf->f_bsize = sbi->cluster_size;
837 buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
838 buf->f_bfree = sbi->free_clusters;
839 buf->f_bavail = sbi->free_clusters;
840 buf->f_fsid = u64_to_fsid(id);
841 buf->f_namelen =
842 (sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE;
843
844 return 0;
845}
846
847static int __fat_write_inode(struct inode *inode, int wait)
848{
849 struct super_block *sb = inode->i_sb;
850 struct msdos_sb_info *sbi = MSDOS_SB(sb);
851 struct buffer_head *bh;
852 struct msdos_dir_entry *raw_entry;
853 loff_t i_pos;
854 sector_t blocknr;
855 int err, offset;
856
857 if (inode->i_ino == MSDOS_ROOT_INO)
858 return 0;
859
860retry:
861 i_pos = fat_i_pos_read(sbi, inode);
862 if (!i_pos)
863 return 0;
864
865 fat_get_blknr_offset(sbi, i_pos, &blocknr, &offset);
866 bh = sb_bread(sb, blocknr);
867 if (!bh) {
868 fat_msg(sb, KERN_ERR, "unable to read inode block "
869 "for updating (i_pos %lld)", i_pos);
870 return -EIO;
871 }
872 spin_lock(&sbi->inode_hash_lock);
873 if (i_pos != MSDOS_I(inode)->i_pos) {
874 spin_unlock(&sbi->inode_hash_lock);
875 brelse(bh);
876 goto retry;
877 }
878
879 raw_entry = &((struct msdos_dir_entry *) (bh->b_data))[offset];
880 if (S_ISDIR(inode->i_mode))
881 raw_entry->size = 0;
882 else
883 raw_entry->size = cpu_to_le32(inode->i_size);
884 raw_entry->attr = fat_make_attrs(inode);
885 fat_set_start(raw_entry, MSDOS_I(inode)->i_logstart);
886 fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
887 &raw_entry->date, NULL);
888 if (sbi->options.isvfat) {
889 __le16 atime;
890 fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime,
891 &raw_entry->cdate, &raw_entry->ctime_cs);
892 fat_time_unix2fat(sbi, &inode->i_atime, &atime,
893 &raw_entry->adate, NULL);
894 }
895 spin_unlock(&sbi->inode_hash_lock);
896 mark_buffer_dirty(bh);
897 err = 0;
898 if (wait)
899 err = sync_dirty_buffer(bh);
900 brelse(bh);
901 return err;
902}
903
904static int fat_write_inode(struct inode *inode, struct writeback_control *wbc)
905{
906 int err;
907
908 if (inode->i_ino == MSDOS_FSINFO_INO) {
909 struct super_block *sb = inode->i_sb;
910
911 mutex_lock(&MSDOS_SB(sb)->s_lock);
912 err = fat_clusters_flush(sb);
913 mutex_unlock(&MSDOS_SB(sb)->s_lock);
914 } else
915 err = __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
916
917 return err;
918}
919
920int fat_sync_inode(struct inode *inode)
921{
922 return __fat_write_inode(inode, 1);
923}
924
925EXPORT_SYMBOL_GPL(fat_sync_inode);
926
927static int fat_show_options(struct seq_file *m, struct dentry *root);
928static const struct super_operations fat_sops = {
929 .alloc_inode = fat_alloc_inode,
930 .free_inode = fat_free_inode,
931 .write_inode = fat_write_inode,
932 .evict_inode = fat_evict_inode,
933 .put_super = fat_put_super,
934 .statfs = fat_statfs,
935 .remount_fs = fat_remount,
936
937 .show_options = fat_show_options,
938};
939
940static int fat_show_options(struct seq_file *m, struct dentry *root)
941{
942 struct msdos_sb_info *sbi = MSDOS_SB(root->d_sb);
943 struct fat_mount_options *opts = &sbi->options;
944 int isvfat = opts->isvfat;
945
946 if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
947 seq_printf(m, ",uid=%u",
948 from_kuid_munged(&init_user_ns, opts->fs_uid));
949 if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
950 seq_printf(m, ",gid=%u",
951 from_kgid_munged(&init_user_ns, opts->fs_gid));
952 seq_printf(m, ",fmask=%04o", opts->fs_fmask);
953 seq_printf(m, ",dmask=%04o", opts->fs_dmask);
954 if (opts->allow_utime)
955 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
956 if (sbi->nls_disk)
957
958 seq_printf(m, ",codepage=%s", &sbi->nls_disk->charset[2]);
959 if (isvfat) {
960 if (sbi->nls_io)
961 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
962
963 switch (opts->shortname) {
964 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
965 seq_puts(m, ",shortname=win95");
966 break;
967 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
968 seq_puts(m, ",shortname=winnt");
969 break;
970 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
971 seq_puts(m, ",shortname=mixed");
972 break;
973 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
974 seq_puts(m, ",shortname=lower");
975 break;
976 default:
977 seq_puts(m, ",shortname=unknown");
978 break;
979 }
980 }
981 if (opts->name_check != 'n')
982 seq_printf(m, ",check=%c", opts->name_check);
983 if (opts->usefree)
984 seq_puts(m, ",usefree");
985 if (opts->quiet)
986 seq_puts(m, ",quiet");
987 if (opts->showexec)
988 seq_puts(m, ",showexec");
989 if (opts->sys_immutable)
990 seq_puts(m, ",sys_immutable");
991 if (!isvfat) {
992 if (opts->dotsOK)
993 seq_puts(m, ",dotsOK=yes");
994 if (opts->nocase)
995 seq_puts(m, ",nocase");
996 } else {
997 if (opts->utf8)
998 seq_puts(m, ",utf8");
999 if (opts->unicode_xlate)
1000 seq_puts(m, ",uni_xlate");
1001 if (!opts->numtail)
1002 seq_puts(m, ",nonumtail");
1003 if (opts->rodir)
1004 seq_puts(m, ",rodir");
1005 }
1006 if (opts->flush)
1007 seq_puts(m, ",flush");
1008 if (opts->tz_set) {
1009 if (opts->time_offset)
1010 seq_printf(m, ",time_offset=%d", opts->time_offset);
1011 else
1012 seq_puts(m, ",tz=UTC");
1013 }
1014 if (opts->errors == FAT_ERRORS_CONT)
1015 seq_puts(m, ",errors=continue");
1016 else if (opts->errors == FAT_ERRORS_PANIC)
1017 seq_puts(m, ",errors=panic");
1018 else
1019 seq_puts(m, ",errors=remount-ro");
1020 if (opts->nfs == FAT_NFS_NOSTALE_RO)
1021 seq_puts(m, ",nfs=nostale_ro");
1022 else if (opts->nfs)
1023 seq_puts(m, ",nfs=stale_rw");
1024 if (opts->discard)
1025 seq_puts(m, ",discard");
1026 if (opts->dos1xfloppy)
1027 seq_puts(m, ",dos1xfloppy");
1028
1029 return 0;
1030}
1031
1032enum {
1033 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
1034 Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
1035 Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
1036 Opt_immutable, Opt_dots, Opt_nodots,
1037 Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
1038 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
1039 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
1040 Opt_obsolete, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
1041 Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_time_offset,
1042 Opt_nfs_stale_rw, Opt_nfs_nostale_ro, Opt_err, Opt_dos1xfloppy,
1043};
1044
1045static const match_table_t fat_tokens = {
1046 {Opt_check_r, "check=relaxed"},
1047 {Opt_check_s, "check=strict"},
1048 {Opt_check_n, "check=normal"},
1049 {Opt_check_r, "check=r"},
1050 {Opt_check_s, "check=s"},
1051 {Opt_check_n, "check=n"},
1052 {Opt_uid, "uid=%u"},
1053 {Opt_gid, "gid=%u"},
1054 {Opt_umask, "umask=%o"},
1055 {Opt_dmask, "dmask=%o"},
1056 {Opt_fmask, "fmask=%o"},
1057 {Opt_allow_utime, "allow_utime=%o"},
1058 {Opt_codepage, "codepage=%u"},
1059 {Opt_usefree, "usefree"},
1060 {Opt_nocase, "nocase"},
1061 {Opt_quiet, "quiet"},
1062 {Opt_showexec, "showexec"},
1063 {Opt_debug, "debug"},
1064 {Opt_immutable, "sys_immutable"},
1065 {Opt_flush, "flush"},
1066 {Opt_tz_utc, "tz=UTC"},
1067 {Opt_time_offset, "time_offset=%d"},
1068 {Opt_err_cont, "errors=continue"},
1069 {Opt_err_panic, "errors=panic"},
1070 {Opt_err_ro, "errors=remount-ro"},
1071 {Opt_discard, "discard"},
1072 {Opt_nfs_stale_rw, "nfs"},
1073 {Opt_nfs_stale_rw, "nfs=stale_rw"},
1074 {Opt_nfs_nostale_ro, "nfs=nostale_ro"},
1075 {Opt_dos1xfloppy, "dos1xfloppy"},
1076 {Opt_obsolete, "conv=binary"},
1077 {Opt_obsolete, "conv=text"},
1078 {Opt_obsolete, "conv=auto"},
1079 {Opt_obsolete, "conv=b"},
1080 {Opt_obsolete, "conv=t"},
1081 {Opt_obsolete, "conv=a"},
1082 {Opt_obsolete, "fat=%u"},
1083 {Opt_obsolete, "blocksize=%u"},
1084 {Opt_obsolete, "cvf_format=%20s"},
1085 {Opt_obsolete, "cvf_options=%100s"},
1086 {Opt_obsolete, "posix"},
1087 {Opt_err, NULL},
1088};
1089static const match_table_t msdos_tokens = {
1090 {Opt_nodots, "nodots"},
1091 {Opt_nodots, "dotsOK=no"},
1092 {Opt_dots, "dots"},
1093 {Opt_dots, "dotsOK=yes"},
1094 {Opt_err, NULL}
1095};
1096static const match_table_t vfat_tokens = {
1097 {Opt_charset, "iocharset=%s"},
1098 {Opt_shortname_lower, "shortname=lower"},
1099 {Opt_shortname_win95, "shortname=win95"},
1100 {Opt_shortname_winnt, "shortname=winnt"},
1101 {Opt_shortname_mixed, "shortname=mixed"},
1102 {Opt_utf8_no, "utf8=0"},
1103 {Opt_utf8_no, "utf8=no"},
1104 {Opt_utf8_no, "utf8=false"},
1105 {Opt_utf8_yes, "utf8=1"},
1106 {Opt_utf8_yes, "utf8=yes"},
1107 {Opt_utf8_yes, "utf8=true"},
1108 {Opt_utf8_yes, "utf8"},
1109 {Opt_uni_xl_no, "uni_xlate=0"},
1110 {Opt_uni_xl_no, "uni_xlate=no"},
1111 {Opt_uni_xl_no, "uni_xlate=false"},
1112 {Opt_uni_xl_yes, "uni_xlate=1"},
1113 {Opt_uni_xl_yes, "uni_xlate=yes"},
1114 {Opt_uni_xl_yes, "uni_xlate=true"},
1115 {Opt_uni_xl_yes, "uni_xlate"},
1116 {Opt_nonumtail_no, "nonumtail=0"},
1117 {Opt_nonumtail_no, "nonumtail=no"},
1118 {Opt_nonumtail_no, "nonumtail=false"},
1119 {Opt_nonumtail_yes, "nonumtail=1"},
1120 {Opt_nonumtail_yes, "nonumtail=yes"},
1121 {Opt_nonumtail_yes, "nonumtail=true"},
1122 {Opt_nonumtail_yes, "nonumtail"},
1123 {Opt_rodir, "rodir"},
1124 {Opt_err, NULL}
1125};
1126
1127static int parse_options(struct super_block *sb, char *options, int is_vfat,
1128 int silent, int *debug, struct fat_mount_options *opts)
1129{
1130 char *p;
1131 substring_t args[MAX_OPT_ARGS];
1132 int option;
1133 char *iocharset;
1134
1135 opts->isvfat = is_vfat;
1136
1137 opts->fs_uid = current_uid();
1138 opts->fs_gid = current_gid();
1139 opts->fs_fmask = opts->fs_dmask = current_umask();
1140 opts->allow_utime = -1;
1141 opts->codepage = fat_default_codepage;
1142 fat_reset_iocharset(opts);
1143 if (is_vfat) {
1144 opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95;
1145 opts->rodir = 0;
1146 } else {
1147 opts->shortname = 0;
1148 opts->rodir = 1;
1149 }
1150 opts->name_check = 'n';
1151 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0;
1152 opts->unicode_xlate = 0;
1153 opts->numtail = 1;
1154 opts->usefree = opts->nocase = 0;
1155 opts->tz_set = 0;
1156 opts->nfs = 0;
1157 opts->errors = FAT_ERRORS_RO;
1158 *debug = 0;
1159
1160 opts->utf8 = IS_ENABLED(CONFIG_FAT_DEFAULT_UTF8) && is_vfat;
1161
1162 if (!options)
1163 goto out;
1164
1165 while ((p = strsep(&options, ",")) != NULL) {
1166 int token;
1167 if (!*p)
1168 continue;
1169
1170 token = match_token(p, fat_tokens, args);
1171 if (token == Opt_err) {
1172 if (is_vfat)
1173 token = match_token(p, vfat_tokens, args);
1174 else
1175 token = match_token(p, msdos_tokens, args);
1176 }
1177 switch (token) {
1178 case Opt_check_s:
1179 opts->name_check = 's';
1180 break;
1181 case Opt_check_r:
1182 opts->name_check = 'r';
1183 break;
1184 case Opt_check_n:
1185 opts->name_check = 'n';
1186 break;
1187 case Opt_usefree:
1188 opts->usefree = 1;
1189 break;
1190 case Opt_nocase:
1191 if (!is_vfat)
1192 opts->nocase = 1;
1193 else {
1194
1195 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1196 | VFAT_SFN_CREATE_WIN95;
1197 }
1198 break;
1199 case Opt_quiet:
1200 opts->quiet = 1;
1201 break;
1202 case Opt_showexec:
1203 opts->showexec = 1;
1204 break;
1205 case Opt_debug:
1206 *debug = 1;
1207 break;
1208 case Opt_immutable:
1209 opts->sys_immutable = 1;
1210 break;
1211 case Opt_uid:
1212 if (match_int(&args[0], &option))
1213 return -EINVAL;
1214 opts->fs_uid = make_kuid(current_user_ns(), option);
1215 if (!uid_valid(opts->fs_uid))
1216 return -EINVAL;
1217 break;
1218 case Opt_gid:
1219 if (match_int(&args[0], &option))
1220 return -EINVAL;
1221 opts->fs_gid = make_kgid(current_user_ns(), option);
1222 if (!gid_valid(opts->fs_gid))
1223 return -EINVAL;
1224 break;
1225 case Opt_umask:
1226 if (match_octal(&args[0], &option))
1227 return -EINVAL;
1228 opts->fs_fmask = opts->fs_dmask = option;
1229 break;
1230 case Opt_dmask:
1231 if (match_octal(&args[0], &option))
1232 return -EINVAL;
1233 opts->fs_dmask = option;
1234 break;
1235 case Opt_fmask:
1236 if (match_octal(&args[0], &option))
1237 return -EINVAL;
1238 opts->fs_fmask = option;
1239 break;
1240 case Opt_allow_utime:
1241 if (match_octal(&args[0], &option))
1242 return -EINVAL;
1243 opts->allow_utime = option & (S_IWGRP | S_IWOTH);
1244 break;
1245 case Opt_codepage:
1246 if (match_int(&args[0], &option))
1247 return -EINVAL;
1248 opts->codepage = option;
1249 break;
1250 case Opt_flush:
1251 opts->flush = 1;
1252 break;
1253 case Opt_time_offset:
1254 if (match_int(&args[0], &option))
1255 return -EINVAL;
1256
1257
1258
1259
1260
1261 if (option < -24 * 60 || option > 24 * 60)
1262 return -EINVAL;
1263 opts->tz_set = 1;
1264 opts->time_offset = option;
1265 break;
1266 case Opt_tz_utc:
1267 opts->tz_set = 1;
1268 opts->time_offset = 0;
1269 break;
1270 case Opt_err_cont:
1271 opts->errors = FAT_ERRORS_CONT;
1272 break;
1273 case Opt_err_panic:
1274 opts->errors = FAT_ERRORS_PANIC;
1275 break;
1276 case Opt_err_ro:
1277 opts->errors = FAT_ERRORS_RO;
1278 break;
1279 case Opt_nfs_stale_rw:
1280 opts->nfs = FAT_NFS_STALE_RW;
1281 break;
1282 case Opt_nfs_nostale_ro:
1283 opts->nfs = FAT_NFS_NOSTALE_RO;
1284 break;
1285 case Opt_dos1xfloppy:
1286 opts->dos1xfloppy = 1;
1287 break;
1288
1289
1290 case Opt_dots:
1291 opts->dotsOK = 1;
1292 break;
1293 case Opt_nodots:
1294 opts->dotsOK = 0;
1295 break;
1296
1297
1298 case Opt_charset:
1299 fat_reset_iocharset(opts);
1300 iocharset = match_strdup(&args[0]);
1301 if (!iocharset)
1302 return -ENOMEM;
1303 opts->iocharset = iocharset;
1304 break;
1305 case Opt_shortname_lower:
1306 opts->shortname = VFAT_SFN_DISPLAY_LOWER
1307 | VFAT_SFN_CREATE_WIN95;
1308 break;
1309 case Opt_shortname_win95:
1310 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1311 | VFAT_SFN_CREATE_WIN95;
1312 break;
1313 case Opt_shortname_winnt:
1314 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1315 | VFAT_SFN_CREATE_WINNT;
1316 break;
1317 case Opt_shortname_mixed:
1318 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1319 | VFAT_SFN_CREATE_WIN95;
1320 break;
1321 case Opt_utf8_no:
1322 opts->utf8 = 0;
1323 break;
1324 case Opt_utf8_yes:
1325 opts->utf8 = 1;
1326 break;
1327 case Opt_uni_xl_no:
1328 opts->unicode_xlate = 0;
1329 break;
1330 case Opt_uni_xl_yes:
1331 opts->unicode_xlate = 1;
1332 break;
1333 case Opt_nonumtail_no:
1334 opts->numtail = 1;
1335 break;
1336 case Opt_nonumtail_yes:
1337 opts->numtail = 0;
1338 break;
1339 case Opt_rodir:
1340 opts->rodir = 1;
1341 break;
1342 case Opt_discard:
1343 opts->discard = 1;
1344 break;
1345
1346
1347 case Opt_obsolete:
1348 fat_msg(sb, KERN_INFO, "\"%s\" option is obsolete, "
1349 "not supported now", p);
1350 break;
1351
1352 default:
1353 if (!silent) {
1354 fat_msg(sb, KERN_ERR,
1355 "Unrecognized mount option \"%s\" "
1356 "or missing value", p);
1357 }
1358 return -EINVAL;
1359 }
1360 }
1361
1362out:
1363
1364 if (!strcmp(opts->iocharset, "utf8")) {
1365 fat_msg(sb, KERN_WARNING, "utf8 is not a recommended IO charset"
1366 " for FAT filesystems, filesystem will be "
1367 "case sensitive!");
1368 }
1369
1370
1371 if (opts->allow_utime == (unsigned short)-1)
1372 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1373 if (opts->unicode_xlate)
1374 opts->utf8 = 0;
1375 if (opts->nfs == FAT_NFS_NOSTALE_RO) {
1376 sb->s_flags |= SB_RDONLY;
1377 sb->s_export_op = &fat_export_ops_nostale;
1378 }
1379
1380 return 0;
1381}
1382
1383static int fat_read_root(struct inode *inode)
1384{
1385 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
1386 int error;
1387
1388 MSDOS_I(inode)->i_pos = MSDOS_ROOT_INO;
1389 inode->i_uid = sbi->options.fs_uid;
1390 inode->i_gid = sbi->options.fs_gid;
1391 inode_inc_iversion(inode);
1392 inode->i_generation = 0;
1393 inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
1394 inode->i_op = sbi->dir_ops;
1395 inode->i_fop = &fat_dir_operations;
1396 if (is_fat32(sbi)) {
1397 MSDOS_I(inode)->i_start = sbi->root_cluster;
1398 error = fat_calc_dir_size(inode);
1399 if (error < 0)
1400 return error;
1401 } else {
1402 MSDOS_I(inode)->i_start = 0;
1403 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1404 }
1405 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1406 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1407 MSDOS_I(inode)->i_logstart = 0;
1408 MSDOS_I(inode)->mmu_private = inode->i_size;
1409
1410 fat_save_attrs(inode, ATTR_DIR);
1411 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1412 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1413 set_nlink(inode, fat_subdirs(inode)+2);
1414
1415 return 0;
1416}
1417
1418static unsigned long calc_fat_clusters(struct super_block *sb)
1419{
1420 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1421
1422
1423 if (!is_fat12(sbi)) {
1424 unsigned long ent_per_sec = sb->s_blocksize * 8 / sbi->fat_bits;
1425 return ent_per_sec * sbi->fat_length;
1426 }
1427
1428 return sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1429}
1430
1431static bool fat_bpb_is_zero(struct fat_boot_sector *b)
1432{
1433 if (get_unaligned_le16(&b->sector_size))
1434 return false;
1435 if (b->sec_per_clus)
1436 return false;
1437 if (b->reserved)
1438 return false;
1439 if (b->fats)
1440 return false;
1441 if (get_unaligned_le16(&b->dir_entries))
1442 return false;
1443 if (get_unaligned_le16(&b->sectors))
1444 return false;
1445 if (b->media)
1446 return false;
1447 if (b->fat_length)
1448 return false;
1449 if (b->secs_track)
1450 return false;
1451 if (b->heads)
1452 return false;
1453 return true;
1454}
1455
1456static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b,
1457 int silent, struct fat_bios_param_block *bpb)
1458{
1459 int error = -EINVAL;
1460
1461
1462 memset(bpb, 0, sizeof(*bpb));
1463 bpb->fat_sector_size = get_unaligned_le16(&b->sector_size);
1464 bpb->fat_sec_per_clus = b->sec_per_clus;
1465 bpb->fat_reserved = le16_to_cpu(b->reserved);
1466 bpb->fat_fats = b->fats;
1467 bpb->fat_dir_entries = get_unaligned_le16(&b->dir_entries);
1468 bpb->fat_sectors = get_unaligned_le16(&b->sectors);
1469 bpb->fat_fat_length = le16_to_cpu(b->fat_length);
1470 bpb->fat_total_sect = le32_to_cpu(b->total_sect);
1471
1472 bpb->fat16_state = b->fat16.state;
1473 bpb->fat16_vol_id = get_unaligned_le32(b->fat16.vol_id);
1474
1475 bpb->fat32_length = le32_to_cpu(b->fat32.length);
1476 bpb->fat32_root_cluster = le32_to_cpu(b->fat32.root_cluster);
1477 bpb->fat32_info_sector = le16_to_cpu(b->fat32.info_sector);
1478 bpb->fat32_state = b->fat32.state;
1479 bpb->fat32_vol_id = get_unaligned_le32(b->fat32.vol_id);
1480
1481
1482 if (!bpb->fat_reserved) {
1483 if (!silent)
1484 fat_msg(sb, KERN_ERR,
1485 "bogus number of reserved sectors");
1486 goto out;
1487 }
1488 if (!bpb->fat_fats) {
1489 if (!silent)
1490 fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
1491 goto out;
1492 }
1493
1494
1495
1496
1497
1498
1499 if (!fat_valid_media(b->media)) {
1500 if (!silent)
1501 fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
1502 (unsigned)b->media);
1503 goto out;
1504 }
1505
1506 if (!is_power_of_2(bpb->fat_sector_size)
1507 || (bpb->fat_sector_size < 512)
1508 || (bpb->fat_sector_size > 4096)) {
1509 if (!silent)
1510 fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
1511 (unsigned)bpb->fat_sector_size);
1512 goto out;
1513 }
1514
1515 if (!is_power_of_2(bpb->fat_sec_per_clus)) {
1516 if (!silent)
1517 fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
1518 (unsigned)bpb->fat_sec_per_clus);
1519 goto out;
1520 }
1521
1522 if (bpb->fat_fat_length == 0 && bpb->fat32_length == 0) {
1523 if (!silent)
1524 fat_msg(sb, KERN_ERR, "bogus number of FAT sectors");
1525 goto out;
1526 }
1527
1528 error = 0;
1529
1530out:
1531 return error;
1532}
1533
1534static int fat_read_static_bpb(struct super_block *sb,
1535 struct fat_boot_sector *b, int silent,
1536 struct fat_bios_param_block *bpb)
1537{
1538 static const char *notdos1x = "This doesn't look like a DOS 1.x volume";
1539
1540 struct fat_floppy_defaults *fdefaults = NULL;
1541 int error = -EINVAL;
1542 sector_t bd_sects;
1543 unsigned i;
1544
1545 bd_sects = i_size_read(sb->s_bdev->bd_inode) / SECTOR_SIZE;
1546
1547
1548 if (b->ignored[0] != 0xeb || b->ignored[2] != 0x90) {
1549 if (!silent)
1550 fat_msg(sb, KERN_ERR,
1551 "%s; no bootstrapping code", notdos1x);
1552 goto out;
1553 }
1554
1555
1556
1557
1558
1559 if (!fat_bpb_is_zero(b)) {
1560 if (!silent)
1561 fat_msg(sb, KERN_ERR,
1562 "%s; DOS 2.x BPB is non-zero", notdos1x);
1563 goto out;
1564 }
1565
1566 for (i = 0; i < ARRAY_SIZE(floppy_defaults); i++) {
1567 if (floppy_defaults[i].nr_sectors == bd_sects) {
1568 fdefaults = &floppy_defaults[i];
1569 break;
1570 }
1571 }
1572
1573 if (fdefaults == NULL) {
1574 if (!silent)
1575 fat_msg(sb, KERN_WARNING,
1576 "This looks like a DOS 1.x volume, but isn't a recognized floppy size (%llu sectors)",
1577 (u64)bd_sects);
1578 goto out;
1579 }
1580
1581 if (!silent)
1582 fat_msg(sb, KERN_INFO,
1583 "This looks like a DOS 1.x volume; assuming default BPB values");
1584
1585 memset(bpb, 0, sizeof(*bpb));
1586 bpb->fat_sector_size = SECTOR_SIZE;
1587 bpb->fat_sec_per_clus = fdefaults->sec_per_clus;
1588 bpb->fat_reserved = 1;
1589 bpb->fat_fats = 2;
1590 bpb->fat_dir_entries = fdefaults->dir_entries;
1591 bpb->fat_sectors = fdefaults->nr_sectors;
1592 bpb->fat_fat_length = fdefaults->fat_length;
1593
1594 error = 0;
1595
1596out:
1597 return error;
1598}
1599
1600
1601
1602
1603int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
1604 void (*setup)(struct super_block *))
1605{
1606 struct inode *root_inode = NULL, *fat_inode = NULL;
1607 struct inode *fsinfo_inode = NULL;
1608 struct buffer_head *bh;
1609 struct fat_bios_param_block bpb;
1610 struct msdos_sb_info *sbi;
1611 u16 logical_sector_size;
1612 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1613 int debug;
1614 long error;
1615 char buf[50];
1616 struct timespec64 ts;
1617
1618
1619
1620
1621
1622
1623
1624 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1625 if (!sbi)
1626 return -ENOMEM;
1627 sb->s_fs_info = sbi;
1628
1629 sb->s_flags |= SB_NODIRATIME;
1630 sb->s_magic = MSDOS_SUPER_MAGIC;
1631 sb->s_op = &fat_sops;
1632 sb->s_export_op = &fat_export_ops;
1633
1634
1635
1636
1637 sb->s_time_gran = 1;
1638 mutex_init(&sbi->nfs_build_inode_lock);
1639 ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
1640 DEFAULT_RATELIMIT_BURST);
1641
1642 error = parse_options(sb, data, isvfat, silent, &debug, &sbi->options);
1643 if (error)
1644 goto out_fail;
1645
1646 setup(sb);
1647
1648 error = -EIO;
1649 sb_min_blocksize(sb, 512);
1650 bh = sb_bread(sb, 0);
1651 if (bh == NULL) {
1652 fat_msg(sb, KERN_ERR, "unable to read boot sector");
1653 goto out_fail;
1654 }
1655
1656 error = fat_read_bpb(sb, (struct fat_boot_sector *)bh->b_data, silent,
1657 &bpb);
1658 if (error == -EINVAL && sbi->options.dos1xfloppy)
1659 error = fat_read_static_bpb(sb,
1660 (struct fat_boot_sector *)bh->b_data, silent, &bpb);
1661 brelse(bh);
1662
1663 if (error == -EINVAL)
1664 goto out_invalid;
1665 else if (error)
1666 goto out_fail;
1667
1668 logical_sector_size = bpb.fat_sector_size;
1669 sbi->sec_per_clus = bpb.fat_sec_per_clus;
1670
1671 error = -EIO;
1672 if (logical_sector_size < sb->s_blocksize) {
1673 fat_msg(sb, KERN_ERR, "logical sector size too small for device"
1674 " (logical sector size = %u)", logical_sector_size);
1675 goto out_fail;
1676 }
1677
1678 if (logical_sector_size > sb->s_blocksize) {
1679 struct buffer_head *bh_resize;
1680
1681 if (!sb_set_blocksize(sb, logical_sector_size)) {
1682 fat_msg(sb, KERN_ERR, "unable to set blocksize %u",
1683 logical_sector_size);
1684 goto out_fail;
1685 }
1686
1687
1688 bh_resize = sb_bread(sb, 0);
1689 if (bh_resize == NULL) {
1690 fat_msg(sb, KERN_ERR, "unable to read boot sector"
1691 " (logical sector size = %lu)",
1692 sb->s_blocksize);
1693 goto out_fail;
1694 }
1695 brelse(bh_resize);
1696 }
1697
1698 mutex_init(&sbi->s_lock);
1699 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1700 sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1701 sbi->fats = bpb.fat_fats;
1702 sbi->fat_bits = 0;
1703 sbi->fat_start = bpb.fat_reserved;
1704 sbi->fat_length = bpb.fat_fat_length;
1705 sbi->root_cluster = 0;
1706 sbi->free_clusters = -1;
1707 sbi->free_clus_valid = 0;
1708 sbi->prev_free = FAT_START_ENT;
1709 sb->s_maxbytes = 0xffffffff;
1710 fat_time_fat2unix(sbi, &ts, 0, cpu_to_le16(FAT_DATE_MIN), 0);
1711 sb->s_time_min = ts.tv_sec;
1712
1713 fat_time_fat2unix(sbi, &ts, cpu_to_le16(FAT_TIME_MAX),
1714 cpu_to_le16(FAT_DATE_MAX), 0);
1715 sb->s_time_max = ts.tv_sec;
1716
1717 if (!sbi->fat_length && bpb.fat32_length) {
1718 struct fat_boot_fsinfo *fsinfo;
1719 struct buffer_head *fsinfo_bh;
1720
1721
1722 sbi->fat_bits = 32;
1723 sbi->fat_length = bpb.fat32_length;
1724 sbi->root_cluster = bpb.fat32_root_cluster;
1725
1726
1727 sbi->fsinfo_sector = bpb.fat32_info_sector;
1728 if (sbi->fsinfo_sector == 0)
1729 sbi->fsinfo_sector = 1;
1730
1731 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1732 if (fsinfo_bh == NULL) {
1733 fat_msg(sb, KERN_ERR, "bread failed, FSINFO block"
1734 " (sector = %lu)", sbi->fsinfo_sector);
1735 goto out_fail;
1736 }
1737
1738 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1739 if (!IS_FSINFO(fsinfo)) {
1740 fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: "
1741 "0x%08x, 0x%08x (sector = %lu)",
1742 le32_to_cpu(fsinfo->signature1),
1743 le32_to_cpu(fsinfo->signature2),
1744 sbi->fsinfo_sector);
1745 } else {
1746 if (sbi->options.usefree)
1747 sbi->free_clus_valid = 1;
1748 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1749 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1750 }
1751
1752 brelse(fsinfo_bh);
1753 }
1754
1755
1756 if (is_fat32(sbi))
1757 sbi->vol_id = bpb.fat32_vol_id;
1758 else
1759 sbi->vol_id = bpb.fat16_vol_id;
1760
1761 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1762 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1763
1764 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1765 sbi->dir_entries = bpb.fat_dir_entries;
1766 if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1767 if (!silent)
1768 fat_msg(sb, KERN_ERR, "bogus number of directory entries"
1769 " (%u)", sbi->dir_entries);
1770 goto out_invalid;
1771 }
1772
1773 rootdir_sectors = sbi->dir_entries
1774 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1775 sbi->data_start = sbi->dir_start + rootdir_sectors;
1776 total_sectors = bpb.fat_sectors;
1777 if (total_sectors == 0)
1778 total_sectors = bpb.fat_total_sect;
1779
1780 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1781
1782 if (!is_fat32(sbi))
1783 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1784
1785
1786 if (is_fat32(sbi))
1787 sbi->dirty = bpb.fat32_state & FAT_STATE_DIRTY;
1788 else
1789 sbi->dirty = bpb.fat16_state & FAT_STATE_DIRTY;
1790
1791
1792 fat_clusters = calc_fat_clusters(sb);
1793 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1794 if (total_clusters > max_fat(sb)) {
1795 if (!silent)
1796 fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
1797 total_clusters);
1798 goto out_invalid;
1799 }
1800
1801 sbi->max_cluster = total_clusters + FAT_START_ENT;
1802
1803 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1804 sbi->free_clusters = -1;
1805
1806 sbi->prev_free %= sbi->max_cluster;
1807 if (sbi->prev_free < FAT_START_ENT)
1808 sbi->prev_free = FAT_START_ENT;
1809
1810
1811 fat_hash_init(sb);
1812 dir_hash_init(sb);
1813 fat_ent_access_init(sb);
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827 error = -EINVAL;
1828 sprintf(buf, "cp%d", sbi->options.codepage);
1829 sbi->nls_disk = load_nls(buf);
1830 if (!sbi->nls_disk) {
1831 fat_msg(sb, KERN_ERR, "codepage %s not found", buf);
1832 goto out_fail;
1833 }
1834
1835
1836 if (sbi->options.isvfat) {
1837 sbi->nls_io = load_nls(sbi->options.iocharset);
1838 if (!sbi->nls_io) {
1839 fat_msg(sb, KERN_ERR, "IO charset %s not found",
1840 sbi->options.iocharset);
1841 goto out_fail;
1842 }
1843 }
1844
1845 error = -ENOMEM;
1846 fat_inode = new_inode(sb);
1847 if (!fat_inode)
1848 goto out_fail;
1849 sbi->fat_inode = fat_inode;
1850
1851 fsinfo_inode = new_inode(sb);
1852 if (!fsinfo_inode)
1853 goto out_fail;
1854 fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
1855 sbi->fsinfo_inode = fsinfo_inode;
1856 insert_inode_hash(fsinfo_inode);
1857
1858 root_inode = new_inode(sb);
1859 if (!root_inode)
1860 goto out_fail;
1861 root_inode->i_ino = MSDOS_ROOT_INO;
1862 inode_set_iversion(root_inode, 1);
1863 error = fat_read_root(root_inode);
1864 if (error < 0) {
1865 iput(root_inode);
1866 goto out_fail;
1867 }
1868 error = -ENOMEM;
1869 insert_inode_hash(root_inode);
1870 fat_attach(root_inode, 0);
1871 sb->s_root = d_make_root(root_inode);
1872 if (!sb->s_root) {
1873 fat_msg(sb, KERN_ERR, "get root inode failed");
1874 goto out_fail;
1875 }
1876
1877 if (sbi->options.discard) {
1878 struct request_queue *q = bdev_get_queue(sb->s_bdev);
1879 if (!blk_queue_discard(q))
1880 fat_msg(sb, KERN_WARNING,
1881 "mounting with \"discard\" option, but "
1882 "the device does not support discard");
1883 }
1884
1885 fat_set_state(sb, 1, 0);
1886 return 0;
1887
1888out_invalid:
1889 error = -EINVAL;
1890 if (!silent)
1891 fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem");
1892
1893out_fail:
1894 if (fsinfo_inode)
1895 iput(fsinfo_inode);
1896 if (fat_inode)
1897 iput(fat_inode);
1898 unload_nls(sbi->nls_io);
1899 unload_nls(sbi->nls_disk);
1900 fat_reset_iocharset(&sbi->options);
1901 sb->s_fs_info = NULL;
1902 kfree(sbi);
1903 return error;
1904}
1905
1906EXPORT_SYMBOL_GPL(fat_fill_super);
1907
1908
1909
1910
1911
1912
1913
1914static int writeback_inode(struct inode *inode)
1915{
1916
1917 int ret;
1918
1919
1920
1921
1922
1923 ret = sync_inode_metadata(inode, 0);
1924 if (!ret)
1925 ret = filemap_fdatawrite(inode->i_mapping);
1926 return ret;
1927}
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1938{
1939 int ret = 0;
1940 if (!MSDOS_SB(sb)->options.flush)
1941 return 0;
1942 if (i1)
1943 ret = writeback_inode(i1);
1944 if (!ret && i2)
1945 ret = writeback_inode(i2);
1946 if (!ret) {
1947 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
1948 ret = filemap_flush(mapping);
1949 }
1950 return ret;
1951}
1952EXPORT_SYMBOL_GPL(fat_flush_inodes);
1953
1954static int __init init_fat_fs(void)
1955{
1956 int err;
1957
1958 err = fat_cache_init();
1959 if (err)
1960 return err;
1961
1962 err = fat_init_inodecache();
1963 if (err)
1964 goto failed;
1965
1966 return 0;
1967
1968failed:
1969 fat_cache_destroy();
1970 return err;
1971}
1972
1973static void __exit exit_fat_fs(void)
1974{
1975 fat_cache_destroy();
1976 fat_destroy_inodecache();
1977}
1978
1979module_init(init_fat_fs)
1980module_exit(exit_fat_fs)
1981
1982MODULE_LICENSE("GPL");
1983