1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * linux/fs/fat/inode.c
4 *
5 * Written 1992,1993 by Werner Almesberger
6 * VFAT extensions by Gordon Chaffee, merged with msdos fs by Henrik Storner
7 * Rewritten for the constant inumbers support by Al Viro
8 *
9 * Fixes:
10 *
11 * Max Cohan: Fixed invalid FSINFO offset when info_sector is 0
12 */
13
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/uio.h>
20 #include <linux/blkdev.h>
21 #include <linux/backing-dev.h>
22 #include <asm/unaligned.h>
23 #include <linux/random.h>
24 #include <linux/iversion.h>
25 #include "fat.h"
26
27 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET
28 /* if user don't select VFAT, this is undefined. */
29 #define CONFIG_FAT_DEFAULT_IOCHARSET ""
30 #endif
31
32 #define KB_IN_SECTORS 2
33
34 /* DOS dates from 1980/1/1 through 2107/12/31 */
35 #define FAT_DATE_MIN (0<<9 | 1<<5 | 1)
36 #define FAT_DATE_MAX (127<<9 | 12<<5 | 31)
37 #define FAT_TIME_MAX (23<<11 | 59<<5 | 29)
38
39 /*
40 * A deserialized copy of the on-disk structure laid out in struct
41 * fat_boot_sector.
42 */
43 struct fat_bios_param_block {
44 u16 fat_sector_size;
45 u8 fat_sec_per_clus;
46 u16 fat_reserved;
47 u8 fat_fats;
48 u16 fat_dir_entries;
49 u16 fat_sectors;
50 u16 fat_fat_length;
51 u32 fat_total_sect;
52
53 u8 fat16_state;
54 u32 fat16_vol_id;
55
56 u32 fat32_length;
57 u32 fat32_root_cluster;
58 u16 fat32_info_sector;
59 u8 fat32_state;
60 u32 fat32_vol_id;
61 };
62
63 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
64 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
65
66 static struct fat_floppy_defaults {
67 unsigned nr_sectors;
68 unsigned sec_per_clus;
69 unsigned dir_entries;
70 unsigned media;
71 unsigned fat_length;
72 } floppy_defaults[] = {
73 {
74 .nr_sectors = 160 * KB_IN_SECTORS,
75 .sec_per_clus = 1,
76 .dir_entries = 64,
77 .media = 0xFE,
78 .fat_length = 1,
79 },
80 {
81 .nr_sectors = 180 * KB_IN_SECTORS,
82 .sec_per_clus = 1,
83 .dir_entries = 64,
84 .media = 0xFC,
85 .fat_length = 2,
86 },
87 {
88 .nr_sectors = 320 * KB_IN_SECTORS,
89 .sec_per_clus = 2,
90 .dir_entries = 112,
91 .media = 0xFF,
92 .fat_length = 1,
93 },
94 {
95 .nr_sectors = 360 * KB_IN_SECTORS,
96 .sec_per_clus = 2,
97 .dir_entries = 112,
98 .media = 0xFD,
99 .fat_length = 2,
100 },
101 };
102
103 int fat_add_cluster(struct inode *inode)
104 {
105 int err, cluster;
106
107 err = fat_alloc_clusters(inode, &cluster, 1);
108 if (err)
109 return err;
110 /* FIXME: this cluster should be added after data of this
111 * cluster is writed */
112 err = fat_chain_add(inode, cluster, 1);
113 if (err)
114 fat_free_clusters(inode, cluster);
115 return err;
116 }
117
118 static inline int __fat_get_block(struct inode *inode, sector_t iblock,
119 unsigned long *max_blocks,
120 struct buffer_head *bh_result, int create)
121 {
122 struct super_block *sb = inode->i_sb;
123 struct msdos_sb_info *sbi = MSDOS_SB(sb);
124 unsigned long mapped_blocks;
125 sector_t phys, last_block;
126 int err, offset;
127
128 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create, false);
129 if (err)
130 return err;
131 if (phys) {
132 map_bh(bh_result, sb, phys);
133 *max_blocks = min(mapped_blocks, *max_blocks);
134 return 0;
135 }
136 if (!create)
137 return 0;
138
139 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
140 fat_fs_error(sb, "corrupted file size (i_pos %lld, %lld)",
141 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
142 return -EIO;
143 }
144
145 last_block = inode->i_blocks >> (sb->s_blocksize_bits - 9);
146 offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
147 /*
148 * allocate a cluster according to the following.
149 * 1) no more available blocks
150 * 2) not part of fallocate region
151 */
152 if (!offset && !(iblock < last_block)) {
153 /* TODO: multiple cluster allocation would be desirable. */
154 err = fat_add_cluster(inode);
155 if (err)
156 return err;
157 }
158 /* available blocks on this cluster */
159 mapped_blocks = sbi->sec_per_clus - offset;
160
161 *max_blocks = min(mapped_blocks, *max_blocks);
162 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
163
164 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create, false);
165 if (err)
166 return err;
167 if (!phys) {
168 fat_fs_error(sb,
169 "invalid FAT chain (i_pos %lld, last_block %llu)",
170 MSDOS_I(inode)->i_pos,
171 (unsigned long long)last_block);
172 return -EIO;
173 }
174
175 BUG_ON(*max_blocks != mapped_blocks);
176 set_buffer_new(bh_result);
177 map_bh(bh_result, sb, phys);
178
179 return 0;
180 }
181
182 static int fat_get_block(struct inode *inode, sector_t iblock,
183 struct buffer_head *bh_result, int create)
184 {
185 struct super_block *sb = inode->i_sb;
186 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
187 int err;
188
189 err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create);
190 if (err)
191 return err;
192 bh_result->b_size = max_blocks << sb->s_blocksize_bits;
193 return 0;
194 }
195
196 static int fat_writepages(struct address_space *mapping,
197 struct writeback_control *wbc)
198 {
199 return mpage_writepages(mapping, wbc, fat_get_block);
200 }
201
202 static int fat_read_folio(struct file *file, struct folio *folio)
203 {
204 return mpage_read_folio(folio, fat_get_block);
205 }
206
207 static void fat_readahead(struct readahead_control *rac)
208 {
209 mpage_readahead(rac, fat_get_block);
210 }
211
212 static void fat_write_failed(struct address_space *mapping, loff_t to)
213 {
214 struct inode *inode = mapping->host;
215
216 if (to > inode->i_size) {
217 truncate_pagecache(inode, inode->i_size);
218 fat_truncate_blocks(inode, inode->i_size);
219 }
220 }
221
222 static int fat_write_begin(struct file *file, struct address_space *mapping,
223 loff_t pos, unsigned len,
224 struct page **pagep, void **fsdata)
225 {
226 int err;
227
228 *pagep = NULL;
229 err = cont_write_begin(file, mapping, pos, len,
230 pagep, fsdata, fat_get_block,
231 &MSDOS_I(mapping->host)->mmu_private);
232 if (err < 0)
233 fat_write_failed(mapping, pos + len);
234 return err;
235 }
236
237 static int fat_write_end(struct file *file, struct address_space *mapping,
238 loff_t pos, unsigned len, unsigned copied,
239 struct page *pagep, void *fsdata)
240 {
241 struct inode *inode = mapping->host;
242 int err;
243 err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
244 if (err < len)
245 fat_write_failed(mapping, pos + len);
246 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
247 fat_truncate_time(inode, NULL, S_CTIME|S_MTIME);
248 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
249 mark_inode_dirty(inode);
250 }
251 return err;
252 }
253
254 static ssize_t fat_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
255 {
256 struct file *file = iocb->ki_filp;
257 struct address_space *mapping = file->f_mapping;
258 struct inode *inode = mapping->host;
259 size_t count = iov_iter_count(iter);
260 loff_t offset = iocb->ki_pos;
261 ssize_t ret;
262
263 if (iov_iter_rw(iter) == WRITE) {
264 /*
265 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
266 * so we need to update the ->mmu_private to block boundary.
267 *
268 * But we must fill the remaining area or hole by nul for
269 * updating ->mmu_private.
270 *
271 * Return 0, and fallback to normal buffered write.
272 */
273 loff_t size = offset + count;
274 if (MSDOS_I(inode)->mmu_private < size)
275 return 0;
276 }
277
278 /*
279 * FAT need to use the DIO_LOCKING for avoiding the race
280 * condition of fat_get_block() and ->truncate().
281 */
282 ret = blockdev_direct_IO(iocb, inode, iter, fat_get_block);
283 if (ret < 0 && iov_iter_rw(iter) == WRITE)
284 fat_write_failed(mapping, offset + count);
285
286 return ret;
287 }
288
289 static int fat_get_block_bmap(struct inode *inode, sector_t iblock,
290 struct buffer_head *bh_result, int create)
291 {
292 struct super_block *sb = inode->i_sb;
293 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
294 int err;
295 sector_t bmap;
296 unsigned long mapped_blocks;
297
298 BUG_ON(create != 0);
299
300 err = fat_bmap(inode, iblock, &bmap, &mapped_blocks, create, true);
301 if (err)
302 return err;
303
304 if (bmap) {
305 map_bh(bh_result, sb, bmap);
306 max_blocks = min(mapped_blocks, max_blocks);
307 }
308
309 bh_result->b_size = max_blocks << sb->s_blocksize_bits;
310
311 return 0;
312 }
313
314 static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
315 {
316 sector_t blocknr;
317
318 /* fat_get_cluster() assumes the requested blocknr isn't truncated. */
319 down_read(&MSDOS_I(mapping->host)->truncate_lock);
320 blocknr = generic_block_bmap(mapping, block, fat_get_block_bmap);
321 up_read(&MSDOS_I(mapping->host)->truncate_lock);
322
323 return blocknr;
324 }
325
326 /*
327 * fat_block_truncate_page() zeroes out a mapping from file offset `from'
328 * up to the end of the block which corresponds to `from'.
329 * This is required during truncate to physically zeroout the tail end
330 * of that block so it doesn't yield old data if the file is later grown.
331 * Also, avoid causing failure from fsx for cases of "data past EOF"
332 */
333 int fat_block_truncate_page(struct inode *inode, loff_t from)
334 {
335 return block_truncate_page(inode->i_mapping, from, fat_get_block);
336 }
337
338 static const struct address_space_operations fat_aops = {
339 .dirty_folio = block_dirty_folio,
340 .invalidate_folio = block_invalidate_folio,
341 .read_folio = fat_read_folio,
342 .readahead = fat_readahead,
343 .writepages = fat_writepages,
344 .write_begin = fat_write_begin,
345 .write_end = fat_write_end,
346 .direct_IO = fat_direct_IO,
347 .bmap = _fat_bmap,
348 .migrate_folio = buffer_migrate_folio,
349 };
350
351 /*
352 * New FAT inode stuff. We do the following:
353 * a) i_ino is constant and has nothing with on-disk location.
354 * b) FAT manages its own cache of directory entries.
355 * c) *This* cache is indexed by on-disk location.
356 * d) inode has an associated directory entry, all right, but
357 * it may be unhashed.
358 * e) currently entries are stored within struct inode. That should
359 * change.
360 * f) we deal with races in the following way:
361 * 1. readdir() and lookup() do FAT-dir-cache lookup.
362 * 2. rename() unhashes the F-d-c entry and rehashes it in
363 * a new place.
364 * 3. unlink() and rmdir() unhash F-d-c entry.
365 * 4. fat_write_inode() checks whether the thing is unhashed.
366 * If it is we silently return. If it isn't we do bread(),
367 * check if the location is still valid and retry if it
368 * isn't. Otherwise we do changes.
369 * 5. Spinlock is used to protect hash/unhash/location check/lookup
370 * 6. fat_evict_inode() unhashes the F-d-c entry.
371 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry
372 * and consider negative result as cache miss.
373 */
374
375 static void fat_hash_init(struct super_block *sb)
376 {
377 struct msdos_sb_info *sbi = MSDOS_SB(sb);
378 int i;
379
380 spin_lock_init(&sbi->inode_hash_lock);
381 for (i = 0; i < FAT_HASH_SIZE; i++)
382 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
383 }
384
385 static inline unsigned long fat_hash(loff_t i_pos)
386 {
387 return hash_32(i_pos, FAT_HASH_BITS);
388 }
389
390 static void dir_hash_init(struct super_block *sb)
391 {
392 struct msdos_sb_info *sbi = MSDOS_SB(sb);
393 int i;
394
395 spin_lock_init(&sbi->dir_hash_lock);
396 for (i = 0; i < FAT_HASH_SIZE; i++)
397 INIT_HLIST_HEAD(&sbi->dir_hashtable[i]);
398 }
399
400 void fat_attach(struct inode *inode, loff_t i_pos)
401 {
402 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
403
404 if (inode->i_ino != MSDOS_ROOT_INO) {
405 struct hlist_head *head = sbi->inode_hashtable
406 + fat_hash(i_pos);
407
408 spin_lock(&sbi->inode_hash_lock);
409 MSDOS_I(inode)->i_pos = i_pos;
410 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
411 spin_unlock(&sbi->inode_hash_lock);
412 }
413
414 /* If NFS support is enabled, cache the mapping of start cluster
415 * to directory inode. This is used during reconnection of
416 * dentries to the filesystem root.
417 */
418 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
419 struct hlist_head *d_head = sbi->dir_hashtable;
420 d_head += fat_dir_hash(MSDOS_I(inode)->i_logstart);
421
422 spin_lock(&sbi->dir_hash_lock);
423 hlist_add_head(&MSDOS_I(inode)->i_dir_hash, d_head);
424 spin_unlock(&sbi->dir_hash_lock);
425 }
426 }
427 EXPORT_SYMBOL_GPL(fat_attach);
428
429 void fat_detach(struct inode *inode)
430 {
431 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
432 spin_lock(&sbi->inode_hash_lock);
433 MSDOS_I(inode)->i_pos = 0;
434 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
435 spin_unlock(&sbi->inode_hash_lock);
436
437 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
438 spin_lock(&sbi->dir_hash_lock);
439 hlist_del_init(&MSDOS_I(inode)->i_dir_hash);
440 spin_unlock(&sbi->dir_hash_lock);
441 }
442 }
443 EXPORT_SYMBOL_GPL(fat_detach);
444
445 struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
446 {
447 struct msdos_sb_info *sbi = MSDOS_SB(sb);
448 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
449 struct msdos_inode_info *i;
450 struct inode *inode = NULL;
451
452 spin_lock(&sbi->inode_hash_lock);
453 hlist_for_each_entry(i, head, i_fat_hash) {
454 BUG_ON(i->vfs_inode.i_sb != sb);
455 if (i->i_pos != i_pos)
456 continue;
457 inode = igrab(&i->vfs_inode);
458 if (inode)
459 break;
460 }
461 spin_unlock(&sbi->inode_hash_lock);
462 return inode;
463 }
464
465 static int is_exec(unsigned char *extension)
466 {
467 unsigned char exe_extensions[] = "EXECOMBAT", *walk;
468
469 for (walk = exe_extensions; *walk; walk += 3)
470 if (!strncmp(extension, walk, 3))
471 return 1;
472 return 0;
473 }
474
475 static int fat_calc_dir_size(struct inode *inode)
476 {
477 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
478 int ret, fclus, dclus;
479
480 inode->i_size = 0;
481 if (MSDOS_I(inode)->i_start == 0)
482 return 0;
483
484 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
485 if (ret < 0)
486 return ret;
487 inode->i_size = (fclus + 1) << sbi->cluster_bits;
488
489 return 0;
490 }
491
492 static int fat_validate_dir(struct inode *dir)
493 {
494 struct super_block *sb = dir->i_sb;
495
496 if (dir->i_nlink < 2) {
497 /* Directory should have "."/".." entries at least. */
498 fat_fs_error(sb, "corrupted directory (invalid entries)");
499 return -EIO;
500 }
501 if (MSDOS_I(dir)->i_start == 0 ||
502 MSDOS_I(dir)->i_start == MSDOS_SB(sb)->root_cluster) {
503 /* Directory should point valid cluster. */
504 fat_fs_error(sb, "corrupted directory (invalid i_start)");
505 return -EIO;
506 }
507 return 0;
508 }
509
510 /* doesn't deal with root inode */
511 int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
512 {
513 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
514 struct timespec64 mtime;
515 int error;
516
517 MSDOS_I(inode)->i_pos = 0;
518 inode->i_uid = sbi->options.fs_uid;
519 inode->i_gid = sbi->options.fs_gid;
520 inode_inc_iversion(inode);
521 inode->i_generation = get_random_u32();
522
523 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
524 inode->i_generation &= ~1;
525 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
526 inode->i_op = sbi->dir_ops;
527 inode->i_fop = &fat_dir_operations;
528
529 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
530 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
531 error = fat_calc_dir_size(inode);
532 if (error < 0)
533 return error;
534 MSDOS_I(inode)->mmu_private = inode->i_size;
535
536 set_nlink(inode, fat_subdirs(inode));
537
538 error = fat_validate_dir(inode);
539 if (error < 0)
540 return error;
541 } else { /* not a directory */
542 inode->i_generation |= 1;
543 inode->i_mode = fat_make_mode(sbi, de->attr,
544 ((sbi->options.showexec && !is_exec(de->name + 8))
545 ? S_IRUGO|S_IWUGO : S_IRWXUGO));
546 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
547
548 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
549 inode->i_size = le32_to_cpu(de->size);
550 inode->i_op = &fat_file_inode_operations;
551 inode->i_fop = &fat_file_operations;
552 inode->i_mapping->a_ops = &fat_aops;
553 MSDOS_I(inode)->mmu_private = inode->i_size;
554 }
555 if (de->attr & ATTR_SYS) {
556 if (sbi->options.sys_immutable)
557 inode->i_flags |= S_IMMUTABLE;
558 }
559 fat_save_attrs(inode, de->attr);
560
561 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
562 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
563
564 fat_time_fat2unix(sbi, &mtime, de->time, de->date, 0);
565 inode_set_mtime_to_ts(inode, mtime);
566 inode_set_ctime_to_ts(inode, mtime);
567 if (sbi->options.isvfat) {
568 struct timespec64 atime;
569
570 fat_time_fat2unix(sbi, &atime, 0, de->adate, 0);
571 inode_set_atime_to_ts(inode, atime);
572 fat_time_fat2unix(sbi, &MSDOS_I(inode)->i_crtime, de->ctime,
573 de->cdate, de->ctime_cs);
574 } else
575 inode_set_atime_to_ts(inode, fat_truncate_atime(sbi, &mtime));
576
577 return 0;
578 }
579
580 static inline void fat_lock_build_inode(struct msdos_sb_info *sbi)
581 {
582 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
583 mutex_lock(&sbi->nfs_build_inode_lock);
584 }
585
586 static inline void fat_unlock_build_inode(struct msdos_sb_info *sbi)
587 {
588 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
589 mutex_unlock(&sbi->nfs_build_inode_lock);
590 }
591
592 struct inode *fat_build_inode(struct super_block *sb,
593 struct msdos_dir_entry *de, loff_t i_pos)
594 {
595 struct inode *inode;
596 int err;
597
598 fat_lock_build_inode(MSDOS_SB(sb));
599 inode = fat_iget(sb, i_pos);
600 if (inode)
601 goto out;
602 inode = new_inode(sb);
603 if (!inode) {
604 inode = ERR_PTR(-ENOMEM);
605 goto out;
606 }
607 inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
608 inode_set_iversion(inode, 1);
609 err = fat_fill_inode(inode, de);
610 if (err) {
611 iput(inode);
612 inode = ERR_PTR(err);
613 goto out;
614 }
615 fat_attach(inode, i_pos);
616 insert_inode_hash(inode);
617 out:
618 fat_unlock_build_inode(MSDOS_SB(sb));
619 return inode;
620 }
621
622 EXPORT_SYMBOL_GPL(fat_build_inode);
623
624 static int __fat_write_inode(struct inode *inode, int wait);
625
626 static void fat_free_eofblocks(struct inode *inode)
627 {
628 /* Release unwritten fallocated blocks on inode eviction. */
629 if ((inode->i_blocks << 9) >
630 round_up(MSDOS_I(inode)->mmu_private,
631 MSDOS_SB(inode->i_sb)->cluster_size)) {
632 int err;
633
634 fat_truncate_blocks(inode, MSDOS_I(inode)->mmu_private);
635 /* Fallocate results in updating the i_start/iogstart
636 * for the zero byte file. So, make it return to
637 * original state during evict and commit it to avoid
638 * any corruption on the next access to the cluster
639 * chain for the file.
640 */
641 err = __fat_write_inode(inode, inode_needs_sync(inode));
642 if (err) {
643 fat_msg(inode->i_sb, KERN_WARNING, "Failed to "
644 "update on disk inode for unused "
645 "fallocated blocks, inode could be "
646 "corrupted. Please run fsck");
647 }
648
649 }
650 }
651
652 static void fat_evict_inode(struct inode *inode)
653 {
654 truncate_inode_pages_final(&inode->i_data);
655 if (!inode->i_nlink) {
656 inode->i_size = 0;
657 fat_truncate_blocks(inode, 0);
658 } else
659 fat_free_eofblocks(inode);
660
661 invalidate_inode_buffers(inode);
662 clear_inode(inode);
663 fat_cache_inval_inode(inode);
664 fat_detach(inode);
665 }
666
667 static void fat_set_state(struct super_block *sb,
668 unsigned int set, unsigned int force)
669 {
670 struct buffer_head *bh;
671 struct fat_boot_sector *b;
672 struct msdos_sb_info *sbi = MSDOS_SB(sb);
673
674 /* do not change any thing if mounted read only */
675 if (sb_rdonly(sb) && !force)
676 return;
677
678 /* do not change state if fs was dirty */
679 if (sbi->dirty) {
680 /* warn only on set (mount). */
681 if (set)
682 fat_msg(sb, KERN_WARNING, "Volume was not properly "
683 "unmounted. Some data may be corrupt. "
684 "Please run fsck.");
685 return;
686 }
687
688 bh = sb_bread(sb, 0);
689 if (bh == NULL) {
690 fat_msg(sb, KERN_ERR, "unable to read boot sector "
691 "to mark fs as dirty");
692 return;
693 }
694
695 b = (struct fat_boot_sector *) bh->b_data;
696
697 if (is_fat32(sbi)) {
698 if (set)
699 b->fat32.state |= FAT_STATE_DIRTY;
700 else
701 b->fat32.state &= ~FAT_STATE_DIRTY;
702 } else /* fat 16 and 12 */ {
703 if (set)
704 b->fat16.state |= FAT_STATE_DIRTY;
705 else
706 b->fat16.state &= ~FAT_STATE_DIRTY;
707 }
708
709 mark_buffer_dirty(bh);
710 sync_dirty_buffer(bh);
711 brelse(bh);
712 }
713
714 static void fat_reset_iocharset(struct fat_mount_options *opts)
715 {
716 if (opts->iocharset != fat_default_iocharset) {
717 /* Note: opts->iocharset can be NULL here */
718 kfree(opts->iocharset);
719 opts->iocharset = fat_default_iocharset;
720 }
721 }
722
723 static void delayed_free(struct rcu_head *p)
724 {
725 struct msdos_sb_info *sbi = container_of(p, struct msdos_sb_info, rcu);
726 unload_nls(sbi->nls_disk);
727 unload_nls(sbi->nls_io);
728 fat_reset_iocharset(&sbi->options);
729 kfree(sbi);
730 }
731
732 static void fat_put_super(struct super_block *sb)
733 {
734 struct msdos_sb_info *sbi = MSDOS_SB(sb);
735
736 fat_set_state(sb, 0, 0);
737
738 iput(sbi->fsinfo_inode);
739 iput(sbi->fat_inode);
740
741 call_rcu(&sbi->rcu, delayed_free);
742 }
743
744 static struct kmem_cache *fat_inode_cachep;
745
746 static struct inode *fat_alloc_inode(struct super_block *sb)
747 {
748 struct msdos_inode_info *ei;
749 ei = alloc_inode_sb(sb, fat_inode_cachep, GFP_NOFS);
750 if (!ei)
751 return NULL;
752
753 init_rwsem(&ei->truncate_lock);
754 /* Zeroing to allow iput() even if partial initialized inode. */
755 ei->mmu_private = 0;
756 ei->i_start = 0;
757 ei->i_logstart = 0;
758 ei->i_attrs = 0;
759 ei->i_pos = 0;
760 ei->i_crtime.tv_sec = 0;
761 ei->i_crtime.tv_nsec = 0;
762
763 return &ei->vfs_inode;
764 }
765
766 static void fat_free_inode(struct inode *inode)
767 {
768 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
769 }
770
771 static void init_once(void *foo)
772 {
773 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
774
775 spin_lock_init(&ei->cache_lru_lock);
776 ei->nr_caches = 0;
777 ei->cache_valid_id = FAT_CACHE_VALID + 1;
778 INIT_LIST_HEAD(&ei->cache_lru);
779 INIT_HLIST_NODE(&ei->i_fat_hash);
780 INIT_HLIST_NODE(&ei->i_dir_hash);
781 inode_init_once(&ei->vfs_inode);
782 }
783
784 static int __init fat_init_inodecache(void)
785 {
786 fat_inode_cachep = kmem_cache_create("fat_inode_cache",
787 sizeof(struct msdos_inode_info),
788 0, (SLAB_RECLAIM_ACCOUNT|
789 SLAB_ACCOUNT),
790 init_once);
791 if (fat_inode_cachep == NULL)
792 return -ENOMEM;
793 return 0;
794 }
795
796 static void __exit fat_destroy_inodecache(void)
797 {
798 /*
799 * Make sure all delayed rcu free inodes are flushed before we
800 * destroy cache.
801 */
802 rcu_barrier();
803 kmem_cache_destroy(fat_inode_cachep);
804 }
805
806 int fat_reconfigure(struct fs_context *fc)
807 {
808 bool new_rdonly;
809 struct super_block *sb = fc->root->d_sb;
810 struct msdos_sb_info *sbi = MSDOS_SB(sb);
811 fc->sb_flags |= SB_NODIRATIME | (sbi->options.isvfat ? 0 : SB_NOATIME);
812
813 sync_filesystem(sb);
814
815 /* make sure we update state on remount. */
816 new_rdonly = fc->sb_flags & SB_RDONLY;
817 if (new_rdonly != sb_rdonly(sb)) {
818 if (new_rdonly)
819 fat_set_state(sb, 0, 0);
820 else
821 fat_set_state(sb, 1, 1);
822 }
823 return 0;
824 }
825 EXPORT_SYMBOL_GPL(fat_reconfigure);
826
827 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
828 {
829 struct super_block *sb = dentry->d_sb;
830 struct msdos_sb_info *sbi = MSDOS_SB(sb);
831 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
832
833 /* If the count of free cluster is still unknown, counts it here. */
834 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
835 int err = fat_count_free_clusters(dentry->d_sb);
836 if (err)
837 return err;
838 }
839
840 buf->f_type = dentry->d_sb->s_magic;
841 buf->f_bsize = sbi->cluster_size;
842 buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
843 buf->f_bfree = sbi->free_clusters;
844 buf->f_bavail = sbi->free_clusters;
845 buf->f_fsid = u64_to_fsid(id);
846 buf->f_namelen =
847 (sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE;
848
849 return 0;
850 }
851
852 static int __fat_write_inode(struct inode *inode, int wait)
853 {
854 struct super_block *sb = inode->i_sb;
855 struct msdos_sb_info *sbi = MSDOS_SB(sb);
856 struct buffer_head *bh;
857 struct msdos_dir_entry *raw_entry;
858 struct timespec64 mtime;
859 loff_t i_pos;
860 sector_t blocknr;
861 int err, offset;
862
863 if (inode->i_ino == MSDOS_ROOT_INO)
864 return 0;
865
866 retry:
867 i_pos = fat_i_pos_read(sbi, inode);
868 if (!i_pos)
869 return 0;
870
871 fat_get_blknr_offset(sbi, i_pos, &blocknr, &offset);
872 bh = sb_bread(sb, blocknr);
873 if (!bh) {
874 fat_msg(sb, KERN_ERR, "unable to read inode block "
875 "for updating (i_pos %lld)", i_pos);
876 return -EIO;
877 }
878 spin_lock(&sbi->inode_hash_lock);
879 if (i_pos != MSDOS_I(inode)->i_pos) {
880 spin_unlock(&sbi->inode_hash_lock);
881 brelse(bh);
882 goto retry;
883 }
884
885 raw_entry = &((struct msdos_dir_entry *) (bh->b_data))[offset];
886 if (S_ISDIR(inode->i_mode))
887 raw_entry->size = 0;
888 else
889 raw_entry->size = cpu_to_le32(inode->i_size);
890 raw_entry->attr = fat_make_attrs(inode);
891 fat_set_start(raw_entry, MSDOS_I(inode)->i_logstart);
892 mtime = inode_get_mtime(inode);
893 fat_time_unix2fat(sbi, &mtime, &raw_entry->time,
894 &raw_entry->date, NULL);
895 if (sbi->options.isvfat) {
896 struct timespec64 ts = inode_get_atime(inode);
897 __le16 atime;
898
899 fat_time_unix2fat(sbi, &ts, &atime, &raw_entry->adate, NULL);
900 fat_time_unix2fat(sbi, &MSDOS_I(inode)->i_crtime, &raw_entry->ctime,
901 &raw_entry->cdate, &raw_entry->ctime_cs);
902 }
903 spin_unlock(&sbi->inode_hash_lock);
904 mark_buffer_dirty(bh);
905 err = 0;
906 if (wait)
907 err = sync_dirty_buffer(bh);
908 brelse(bh);
909 return err;
910 }
911
912 static int fat_write_inode(struct inode *inode, struct writeback_control *wbc)
913 {
914 int err;
915
916 if (inode->i_ino == MSDOS_FSINFO_INO) {
917 struct super_block *sb = inode->i_sb;
918
919 mutex_lock(&MSDOS_SB(sb)->s_lock);
920 err = fat_clusters_flush(sb);
921 mutex_unlock(&MSDOS_SB(sb)->s_lock);
922 } else
923 err = __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
924
925 return err;
926 }
927
928 int fat_sync_inode(struct inode *inode)
929 {
930 return __fat_write_inode(inode, 1);
931 }
932
933 EXPORT_SYMBOL_GPL(fat_sync_inode);
934
935 static int fat_show_options(struct seq_file *m, struct dentry *root);
936 static const struct super_operations fat_sops = {
937 .alloc_inode = fat_alloc_inode,
938 .free_inode = fat_free_inode,
939 .write_inode = fat_write_inode,
940 .evict_inode = fat_evict_inode,
941 .put_super = fat_put_super,
942 .statfs = fat_statfs,
943 .show_options = fat_show_options,
944 };
945
946 static int fat_show_options(struct seq_file *m, struct dentry *root)
947 {
948 struct msdos_sb_info *sbi = MSDOS_SB(root->d_sb);
949 struct fat_mount_options *opts = &sbi->options;
950 int isvfat = opts->isvfat;
951
952 if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
953 seq_printf(m, ",uid=%u",
954 from_kuid_munged(&init_user_ns, opts->fs_uid));
955 if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
956 seq_printf(m, ",gid=%u",
957 from_kgid_munged(&init_user_ns, opts->fs_gid));
958 seq_printf(m, ",fmask=%04o", opts->fs_fmask);
959 seq_printf(m, ",dmask=%04o", opts->fs_dmask);
960 if (opts->allow_utime)
961 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
962 if (sbi->nls_disk)
963 /* strip "cp" prefix from displayed option */
964 seq_printf(m, ",codepage=%s", &sbi->nls_disk->charset[2]);
965 if (isvfat) {
966 if (sbi->nls_io)
967 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
968
969 switch (opts->shortname) {
970 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
971 seq_puts(m, ",shortname=win95");
972 break;
973 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
974 seq_puts(m, ",shortname=winnt");
975 break;
976 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
977 seq_puts(m, ",shortname=mixed");
978 break;
979 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
980 seq_puts(m, ",shortname=lower");
981 break;
982 default:
983 seq_puts(m, ",shortname=unknown");
984 break;
985 }
986 }
987 if (opts->name_check != 'n')
988 seq_printf(m, ",check=%c", opts->name_check);
989 if (opts->usefree)
990 seq_puts(m, ",usefree");
991 if (opts->quiet)
992 seq_puts(m, ",quiet");
993 if (opts->showexec)
994 seq_puts(m, ",showexec");
995 if (opts->sys_immutable)
996 seq_puts(m, ",sys_immutable");
997 if (!isvfat) {
998 if (opts->dotsOK)
999 seq_puts(m, ",dotsOK=yes");
1000 if (opts->nocase)
1001 seq_puts(m, ",nocase");
1002 } else {
1003 if (opts->utf8)
1004 seq_puts(m, ",utf8");
1005 if (opts->unicode_xlate)
1006 seq_puts(m, ",uni_xlate");
1007 if (!opts->numtail)
1008 seq_puts(m, ",nonumtail");
1009 if (opts->rodir)
1010 seq_puts(m, ",rodir");
1011 }
1012 if (opts->flush)
1013 seq_puts(m, ",flush");
1014 if (opts->tz_set) {
1015 if (opts->time_offset)
1016 seq_printf(m, ",time_offset=%d", opts->time_offset);
1017 else
1018 seq_puts(m, ",tz=UTC");
1019 }
1020 if (opts->errors == FAT_ERRORS_CONT)
1021 seq_puts(m, ",errors=continue");
1022 else if (opts->errors == FAT_ERRORS_PANIC)
1023 seq_puts(m, ",errors=panic");
1024 else
1025 seq_puts(m, ",errors=remount-ro");
1026 if (opts->nfs == FAT_NFS_NOSTALE_RO)
1027 seq_puts(m, ",nfs=nostale_ro");
1028 else if (opts->nfs)
1029 seq_puts(m, ",nfs=stale_rw");
1030 if (opts->discard)
1031 seq_puts(m, ",discard");
1032 if (opts->dos1xfloppy)
1033 seq_puts(m, ",dos1xfloppy");
1034
1035 return 0;
1036 }
1037
1038 enum {
1039 Opt_check, Opt_uid, Opt_gid, Opt_umask, Opt_dmask, Opt_fmask,
1040 Opt_allow_utime, Opt_codepage, Opt_usefree, Opt_nocase, Opt_quiet,
1041 Opt_showexec, Opt_debug, Opt_immutable, Opt_dots, Opt_dotsOK,
1042 Opt_charset, Opt_shortname, Opt_utf8, Opt_utf8_bool,
1043 Opt_uni_xl, Opt_uni_xl_bool, Opt_nonumtail, Opt_nonumtail_bool,
1044 Opt_obsolete, Opt_flush, Opt_tz, Opt_rodir, Opt_errors, Opt_discard,
1045 Opt_nfs, Opt_nfs_enum, Opt_time_offset, Opt_dos1xfloppy,
1046 };
1047
1048 static const struct constant_table fat_param_check[] = {
1049 {"relaxed", 'r'},
1050 {"r", 'r'},
1051 {"strict", 's'},
1052 {"s", 's'},
1053 {"normal", 'n'},
1054 {"n", 'n'},
1055 {}
1056 };
1057
1058 static const struct constant_table fat_param_tz[] = {
1059 {"UTC", 0},
1060 {}
1061 };
1062
1063 static const struct constant_table fat_param_errors[] = {
1064 {"continue", FAT_ERRORS_CONT},
1065 {"panic", FAT_ERRORS_PANIC},
1066 {"remount-ro", FAT_ERRORS_RO},
1067 {}
1068 };
1069
1070
1071 static const struct constant_table fat_param_nfs[] = {
1072 {"stale_rw", FAT_NFS_STALE_RW},
1073 {"nostale_ro", FAT_NFS_NOSTALE_RO},
1074 {}
1075 };
1076
1077 /*
1078 * These are all obsolete but we still reject invalid options.
1079 * The corresponding values are therefore meaningless.
1080 */
1081 static const struct constant_table fat_param_conv[] = {
1082 {"binary", 0},
1083 {"text", 0},
1084 {"auto", 0},
1085 {"b", 0},
1086 {"t", 0},
1087 {"a", 0},
1088 {}
1089 };
1090
1091 /* Core options. See below for vfat and msdos extras */
1092 const struct fs_parameter_spec fat_param_spec[] = {
1093 fsparam_enum ("check", Opt_check, fat_param_check),
1094 fsparam_uid ("uid", Opt_uid),
1095 fsparam_gid ("gid", Opt_gid),
1096 fsparam_u32oct ("umask", Opt_umask),
1097 fsparam_u32oct ("dmask", Opt_dmask),
1098 fsparam_u32oct ("fmask", Opt_fmask),
1099 fsparam_u32oct ("allow_utime", Opt_allow_utime),
1100 fsparam_u32 ("codepage", Opt_codepage),
1101 fsparam_flag ("usefree", Opt_usefree),
1102 fsparam_flag ("nocase", Opt_nocase),
1103 fsparam_flag ("quiet", Opt_quiet),
1104 fsparam_flag ("showexec", Opt_showexec),
1105 fsparam_flag ("debug", Opt_debug),
1106 fsparam_flag ("sys_immutable", Opt_immutable),
1107 fsparam_flag ("flush", Opt_flush),
1108 fsparam_enum ("tz", Opt_tz, fat_param_tz),
1109 fsparam_s32 ("time_offset", Opt_time_offset),
1110 fsparam_enum ("errors", Opt_errors, fat_param_errors),
1111 fsparam_flag ("discard", Opt_discard),
1112 fsparam_flag ("nfs", Opt_nfs),
1113 fsparam_enum ("nfs", Opt_nfs_enum, fat_param_nfs),
1114 fsparam_flag ("dos1xfloppy", Opt_dos1xfloppy),
1115 __fsparam(fs_param_is_enum, "conv",
1116 Opt_obsolete, fs_param_deprecated, fat_param_conv),
1117 __fsparam(fs_param_is_u32, "fat",
1118 Opt_obsolete, fs_param_deprecated, NULL),
1119 __fsparam(fs_param_is_u32, "blocksize",
1120 Opt_obsolete, fs_param_deprecated, NULL),
1121 __fsparam(fs_param_is_string, "cvf_format",
1122 Opt_obsolete, fs_param_deprecated, NULL),
1123 __fsparam(fs_param_is_string, "cvf_options",
1124 Opt_obsolete, fs_param_deprecated, NULL),
1125 __fsparam(NULL, "posix",
1126 Opt_obsolete, fs_param_deprecated, NULL),
1127 {}
1128 };
1129 EXPORT_SYMBOL_GPL(fat_param_spec);
1130
1131 static const struct fs_parameter_spec msdos_param_spec[] = {
1132 fsparam_flag_no ("dots", Opt_dots),
1133 fsparam_bool ("dotsOK", Opt_dotsOK),
1134 {}
1135 };
1136
1137 static const struct constant_table fat_param_shortname[] = {
1138 {"lower", VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95},
1139 {"win95", VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95},
1140 {"winnt", VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT},
1141 {"mixed", VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95},
1142 {}
1143 };
1144
1145 static const struct fs_parameter_spec vfat_param_spec[] = {
1146 fsparam_string ("iocharset", Opt_charset),
1147 fsparam_enum ("shortname", Opt_shortname, fat_param_shortname),
1148 fsparam_flag ("utf8", Opt_utf8),
1149 fsparam_bool ("utf8", Opt_utf8_bool),
1150 fsparam_flag ("uni_xlate", Opt_uni_xl),
1151 fsparam_bool ("uni_xlate", Opt_uni_xl_bool),
1152 fsparam_flag ("nonumtail", Opt_nonumtail),
1153 fsparam_bool ("nonumtail", Opt_nonumtail_bool),
1154 fsparam_flag ("rodir", Opt_rodir),
1155 {}
1156 };
1157
1158 int fat_parse_param(struct fs_context *fc, struct fs_parameter *param,
1159 bool is_vfat)
1160 {
1161 struct fat_mount_options *opts = fc->fs_private;
1162 struct fs_parse_result result;
1163 int opt;
1164
1165 /* remount options have traditionally been ignored */
1166 if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE)
1167 return 0;
1168
1169 opt = fs_parse(fc, fat_param_spec, param, &result);
1170 /* If option not found in fat_param_spec, try vfat/msdos options */
1171 if (opt == -ENOPARAM) {
1172 if (is_vfat)
1173 opt = fs_parse(fc, vfat_param_spec, param, &result);
1174 else
1175 opt = fs_parse(fc, msdos_param_spec, param, &result);
1176 }
1177
1178 if (opt < 0)
1179 return opt;
1180
1181 switch (opt) {
1182 case Opt_check:
1183 opts->name_check = result.uint_32;
1184 break;
1185 case Opt_usefree:
1186 opts->usefree = 1;
1187 break;
1188 case Opt_nocase:
1189 if (!is_vfat)
1190 opts->nocase = 1;
1191 else {
1192 /* for backward compatibility */
1193 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1194 | VFAT_SFN_CREATE_WIN95;
1195 }
1196 break;
1197 case Opt_quiet:
1198 opts->quiet = 1;
1199 break;
1200 case Opt_showexec:
1201 opts->showexec = 1;
1202 break;
1203 case Opt_debug:
1204 opts->debug = 1;
1205 break;
1206 case Opt_immutable:
1207 opts->sys_immutable = 1;
1208 break;
1209 case Opt_uid:
1210 opts->fs_uid = result.uid;
1211 break;
1212 case Opt_gid:
1213 opts->fs_gid = result.gid;
1214 break;
1215 case Opt_umask:
1216 opts->fs_fmask = opts->fs_dmask = result.uint_32;
1217 break;
1218 case Opt_dmask:
1219 opts->fs_dmask = result.uint_32;
1220 break;
1221 case Opt_fmask:
1222 opts->fs_fmask = result.uint_32;
1223 break;
1224 case Opt_allow_utime:
1225 opts->allow_utime = result.uint_32 & (S_IWGRP | S_IWOTH);
1226 break;
1227 case Opt_codepage:
1228 opts->codepage = result.uint_32;
1229 break;
1230 case Opt_flush:
1231 opts->flush = 1;
1232 break;
1233 case Opt_time_offset:
1234 /*
1235 * GMT+-12 zones may have DST corrections so at least
1236 * 13 hours difference is needed. Make the limit 24
1237 * just in case someone invents something unusual.
1238 */
1239 if (result.int_32 < -24 * 60 || result.int_32 > 24 * 60)
1240 return -EINVAL;
1241 opts->tz_set = 1;
1242 opts->time_offset = result.int_32;
1243 break;
1244 case Opt_tz:
1245 opts->tz_set = 1;
1246 opts->time_offset = result.uint_32;
1247 break;
1248 case Opt_errors:
1249 opts->errors = result.uint_32;
1250 break;
1251 case Opt_nfs:
1252 opts->nfs = FAT_NFS_STALE_RW;
1253 break;
1254 case Opt_nfs_enum:
1255 opts->nfs = result.uint_32;
1256 break;
1257 case Opt_dos1xfloppy:
1258 opts->dos1xfloppy = 1;
1259 break;
1260
1261 /* msdos specific */
1262 case Opt_dots: /* dots / nodots */
1263 opts->dotsOK = !result.negated;
1264 break;
1265 case Opt_dotsOK: /* dotsOK = yes/no */
1266 opts->dotsOK = result.boolean;
1267 break;
1268
1269 /* vfat specific */
1270 case Opt_charset:
1271 fat_reset_iocharset(opts);
1272 opts->iocharset = param->string;
1273 param->string = NULL; /* Steal string */
1274 break;
1275 case Opt_shortname:
1276 opts->shortname = result.uint_32;
1277 break;
1278 case Opt_utf8:
1279 opts->utf8 = 1;
1280 break;
1281 case Opt_utf8_bool:
1282 opts->utf8 = result.boolean;
1283 break;
1284 case Opt_uni_xl:
1285 opts->unicode_xlate = 1;
1286 break;
1287 case Opt_uni_xl_bool:
1288 opts->unicode_xlate = result.boolean;
1289 break;
1290 case Opt_nonumtail:
1291 opts->numtail = 0; /* negated option */
1292 break;
1293 case Opt_nonumtail_bool:
1294 opts->numtail = !result.boolean; /* negated option */
1295 break;
1296 case Opt_rodir:
1297 opts->rodir = 1;
1298 break;
1299 case Opt_discard:
1300 opts->discard = 1;
1301 break;
1302
1303 /* obsolete mount options */
1304 case Opt_obsolete:
1305 printk(KERN_INFO "FAT-fs: \"%s\" option is obsolete, "
1306 "not supported now", param->key);
1307 break;
1308 default:
1309 return -EINVAL;
1310 }
1311
1312 return 0;
1313 }
1314 EXPORT_SYMBOL_GPL(fat_parse_param);
1315
1316 static int fat_read_root(struct inode *inode)
1317 {
1318 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
1319 int error;
1320
1321 MSDOS_I(inode)->i_pos = MSDOS_ROOT_INO;
1322 inode->i_uid = sbi->options.fs_uid;
1323 inode->i_gid = sbi->options.fs_gid;
1324 inode_inc_iversion(inode);
1325 inode->i_generation = 0;
1326 inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
1327 inode->i_op = sbi->dir_ops;
1328 inode->i_fop = &fat_dir_operations;
1329 if (is_fat32(sbi)) {
1330 MSDOS_I(inode)->i_start = sbi->root_cluster;
1331 error = fat_calc_dir_size(inode);
1332 if (error < 0)
1333 return error;
1334 } else {
1335 MSDOS_I(inode)->i_start = 0;
1336 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1337 }
1338 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1339 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1340 MSDOS_I(inode)->i_logstart = 0;
1341 MSDOS_I(inode)->mmu_private = inode->i_size;
1342
1343 fat_save_attrs(inode, ATTR_DIR);
1344 inode_set_mtime_to_ts(inode,
1345 inode_set_atime_to_ts(inode, inode_set_ctime(inode, 0, 0)));
1346 set_nlink(inode, fat_subdirs(inode)+2);
1347
1348 return 0;
1349 }
1350
1351 static unsigned long calc_fat_clusters(struct super_block *sb)
1352 {
1353 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1354
1355 /* Divide first to avoid overflow */
1356 if (!is_fat12(sbi)) {
1357 unsigned long ent_per_sec = sb->s_blocksize * 8 / sbi->fat_bits;
1358 return ent_per_sec * sbi->fat_length;
1359 }
1360
1361 return sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1362 }
1363
1364 static bool fat_bpb_is_zero(struct fat_boot_sector *b)
1365 {
1366 if (get_unaligned_le16(&b->sector_size))
1367 return false;
1368 if (b->sec_per_clus)
1369 return false;
1370 if (b->reserved)
1371 return false;
1372 if (b->fats)
1373 return false;
1374 if (get_unaligned_le16(&b->dir_entries))
1375 return false;
1376 if (get_unaligned_le16(&b->sectors))
1377 return false;
1378 if (b->media)
1379 return false;
1380 if (b->fat_length)
1381 return false;
1382 if (b->secs_track)
1383 return false;
1384 if (b->heads)
1385 return false;
1386 return true;
1387 }
1388
1389 static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b,
1390 int silent, struct fat_bios_param_block *bpb)
1391 {
1392 int error = -EINVAL;
1393
1394 /* Read in BPB ... */
1395 memset(bpb, 0, sizeof(*bpb));
1396 bpb->fat_sector_size = get_unaligned_le16(&b->sector_size);
1397 bpb->fat_sec_per_clus = b->sec_per_clus;
1398 bpb->fat_reserved = le16_to_cpu(b->reserved);
1399 bpb->fat_fats = b->fats;
1400 bpb->fat_dir_entries = get_unaligned_le16(&b->dir_entries);
1401 bpb->fat_sectors = get_unaligned_le16(&b->sectors);
1402 bpb->fat_fat_length = le16_to_cpu(b->fat_length);
1403 bpb->fat_total_sect = le32_to_cpu(b->total_sect);
1404
1405 bpb->fat16_state = b->fat16.state;
1406 bpb->fat16_vol_id = get_unaligned_le32(b->fat16.vol_id);
1407
1408 bpb->fat32_length = le32_to_cpu(b->fat32.length);
1409 bpb->fat32_root_cluster = le32_to_cpu(b->fat32.root_cluster);
1410 bpb->fat32_info_sector = le16_to_cpu(b->fat32.info_sector);
1411 bpb->fat32_state = b->fat32.state;
1412 bpb->fat32_vol_id = get_unaligned_le32(b->fat32.vol_id);
1413
1414 /* Validate this looks like a FAT filesystem BPB */
1415 if (!bpb->fat_reserved) {
1416 if (!silent)
1417 fat_msg(sb, KERN_ERR,
1418 "bogus number of reserved sectors");
1419 goto out;
1420 }
1421 if (!bpb->fat_fats) {
1422 if (!silent)
1423 fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
1424 goto out;
1425 }
1426
1427 /*
1428 * Earlier we checked here that b->secs_track and b->head are nonzero,
1429 * but it turns out valid FAT filesystems can have zero there.
1430 */
1431
1432 if (!fat_valid_media(b->media)) {
1433 if (!silent)
1434 fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
1435 (unsigned)b->media);
1436 goto out;
1437 }
1438
1439 if (!is_power_of_2(bpb->fat_sector_size)
1440 || (bpb->fat_sector_size < 512)
1441 || (bpb->fat_sector_size > 4096)) {
1442 if (!silent)
1443 fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
1444 (unsigned)bpb->fat_sector_size);
1445 goto out;
1446 }
1447
1448 if (!is_power_of_2(bpb->fat_sec_per_clus)) {
1449 if (!silent)
1450 fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
1451 (unsigned)bpb->fat_sec_per_clus);
1452 goto out;
1453 }
1454
1455 if (bpb->fat_fat_length == 0 && bpb->fat32_length == 0) {
1456 if (!silent)
1457 fat_msg(sb, KERN_ERR, "bogus number of FAT sectors");
1458 goto out;
1459 }
1460
1461 error = 0;
1462
1463 out:
1464 return error;
1465 }
1466
1467 static int fat_read_static_bpb(struct super_block *sb,
1468 struct fat_boot_sector *b, int silent,
1469 struct fat_bios_param_block *bpb)
1470 {
1471 static const char *notdos1x = "This doesn't look like a DOS 1.x volume";
1472 sector_t bd_sects = bdev_nr_sectors(sb->s_bdev);
1473 struct fat_floppy_defaults *fdefaults = NULL;
1474 int error = -EINVAL;
1475 unsigned i;
1476
1477 /* 16-bit DOS 1.x reliably wrote bootstrap short-jmp code */
1478 if (b->ignored[0] != 0xeb || b->ignored[2] != 0x90) {
1479 if (!silent)
1480 fat_msg(sb, KERN_ERR,
1481 "%s; no bootstrapping code", notdos1x);
1482 goto out;
1483 }
1484
1485 /*
1486 * If any value in this region is non-zero, it isn't archaic
1487 * DOS.
1488 */
1489 if (!fat_bpb_is_zero(b)) {
1490 if (!silent)
1491 fat_msg(sb, KERN_ERR,
1492 "%s; DOS 2.x BPB is non-zero", notdos1x);
1493 goto out;
1494 }
1495
1496 for (i = 0; i < ARRAY_SIZE(floppy_defaults); i++) {
1497 if (floppy_defaults[i].nr_sectors == bd_sects) {
1498 fdefaults = &floppy_defaults[i];
1499 break;
1500 }
1501 }
1502
1503 if (fdefaults == NULL) {
1504 if (!silent)
1505 fat_msg(sb, KERN_WARNING,
1506 "This looks like a DOS 1.x volume, but isn't a recognized floppy size (%llu sectors)",
1507 (u64)bd_sects);
1508 goto out;
1509 }
1510
1511 if (!silent)
1512 fat_msg(sb, KERN_INFO,
1513 "This looks like a DOS 1.x volume; assuming default BPB values");
1514
1515 memset(bpb, 0, sizeof(*bpb));
1516 bpb->fat_sector_size = SECTOR_SIZE;
1517 bpb->fat_sec_per_clus = fdefaults->sec_per_clus;
1518 bpb->fat_reserved = 1;
1519 bpb->fat_fats = 2;
1520 bpb->fat_dir_entries = fdefaults->dir_entries;
1521 bpb->fat_sectors = fdefaults->nr_sectors;
1522 bpb->fat_fat_length = fdefaults->fat_length;
1523
1524 error = 0;
1525
1526 out:
1527 return error;
1528 }
1529
1530 /*
1531 * Read the super block of an MS-DOS FS.
1532 */
1533 int fat_fill_super(struct super_block *sb, struct fs_context *fc,
1534 void (*setup)(struct super_block *))
1535 {
1536 struct fat_mount_options *opts = fc->fs_private;
1537 int silent = fc->sb_flags & SB_SILENT;
1538 struct inode *root_inode = NULL, *fat_inode = NULL;
1539 struct inode *fsinfo_inode = NULL;
1540 struct buffer_head *bh;
1541 struct fat_bios_param_block bpb;
1542 struct msdos_sb_info *sbi;
1543 u16 logical_sector_size;
1544 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1545 long error;
1546 char buf[50];
1547 struct timespec64 ts;
1548
1549 /*
1550 * GFP_KERNEL is ok here, because while we do hold the
1551 * superblock lock, memory pressure can't call back into
1552 * the filesystem, since we're only just about to mount
1553 * it and have no inodes etc active!
1554 */
1555 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1556 if (!sbi)
1557 return -ENOMEM;
1558 sb->s_fs_info = sbi;
1559
1560 sb->s_flags |= SB_NODIRATIME;
1561 sb->s_magic = MSDOS_SUPER_MAGIC;
1562 sb->s_op = &fat_sops;
1563 sb->s_export_op = &fat_export_ops;
1564 /*
1565 * fat timestamps are complex and truncated by fat itself, so
1566 * we set 1 here to be fast
1567 */
1568 sb->s_time_gran = 1;
1569 mutex_init(&sbi->nfs_build_inode_lock);
1570 ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
1571 DEFAULT_RATELIMIT_BURST);
1572
1573 /* UTF-8 doesn't provide FAT semantics */
1574 if (!strcmp(opts->iocharset, "utf8")) {
1575 fat_msg(sb, KERN_WARNING, "utf8 is not a recommended IO charset"
1576 " for FAT filesystems, filesystem will be"
1577 " case sensitive!");
1578 }
1579
1580 /* If user doesn't specify allow_utime, it's initialized from dmask. */
1581 if (opts->allow_utime == (unsigned short)-1)
1582 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1583 if (opts->unicode_xlate)
1584 opts->utf8 = 0;
1585 if (opts->nfs == FAT_NFS_NOSTALE_RO) {
1586 sb->s_flags |= SB_RDONLY;
1587 sb->s_export_op = &fat_export_ops_nostale;
1588 }
1589
1590 /* Apply parsed options to sbi (structure copy) */
1591 sbi->options = *opts;
1592 /* Transfer ownership of iocharset to sbi->options */
1593 opts->iocharset = NULL;
1594
1595 setup(sb); /* flavour-specific stuff that needs options */
1596
1597 error = -EIO;
1598 sb_min_blocksize(sb, 512);
1599 bh = sb_bread(sb, 0);
1600 if (bh == NULL) {
1601 fat_msg(sb, KERN_ERR, "unable to read boot sector");
1602 goto out_fail;
1603 }
1604
1605 error = fat_read_bpb(sb, (struct fat_boot_sector *)bh->b_data, silent,
1606 &bpb);
1607 if (error == -EINVAL && sbi->options.dos1xfloppy)
1608 error = fat_read_static_bpb(sb,
1609 (struct fat_boot_sector *)bh->b_data, silent, &bpb);
1610 brelse(bh);
1611
1612 if (error == -EINVAL)
1613 goto out_invalid;
1614 else if (error)
1615 goto out_fail;
1616
1617 logical_sector_size = bpb.fat_sector_size;
1618 sbi->sec_per_clus = bpb.fat_sec_per_clus;
1619
1620 error = -EIO;
1621 if (logical_sector_size < sb->s_blocksize) {
1622 fat_msg(sb, KERN_ERR, "logical sector size too small for device"
1623 " (logical sector size = %u)", logical_sector_size);
1624 goto out_fail;
1625 }
1626
1627 if (logical_sector_size > sb->s_blocksize) {
1628 struct buffer_head *bh_resize;
1629
1630 if (!sb_set_blocksize(sb, logical_sector_size)) {
1631 fat_msg(sb, KERN_ERR, "unable to set blocksize %u",
1632 logical_sector_size);
1633 goto out_fail;
1634 }
1635
1636 /* Verify that the larger boot sector is fully readable */
1637 bh_resize = sb_bread(sb, 0);
1638 if (bh_resize == NULL) {
1639 fat_msg(sb, KERN_ERR, "unable to read boot sector"
1640 " (logical sector size = %lu)",
1641 sb->s_blocksize);
1642 goto out_fail;
1643 }
1644 brelse(bh_resize);
1645 }
1646
1647 mutex_init(&sbi->s_lock);
1648 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1649 sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1650 sbi->fats = bpb.fat_fats;
1651 sbi->fat_bits = 0; /* Don't know yet */
1652 sbi->fat_start = bpb.fat_reserved;
1653 sbi->fat_length = bpb.fat_fat_length;
1654 sbi->root_cluster = 0;
1655 sbi->free_clusters = -1; /* Don't know yet */
1656 sbi->free_clus_valid = 0;
1657 sbi->prev_free = FAT_START_ENT;
1658 sb->s_maxbytes = 0xffffffff;
1659 fat_time_fat2unix(sbi, &ts, 0, cpu_to_le16(FAT_DATE_MIN), 0);
1660 sb->s_time_min = ts.tv_sec;
1661
1662 fat_time_fat2unix(sbi, &ts, cpu_to_le16(FAT_TIME_MAX),
1663 cpu_to_le16(FAT_DATE_MAX), 0);
1664 sb->s_time_max = ts.tv_sec;
1665
1666 if (!sbi->fat_length && bpb.fat32_length) {
1667 struct fat_boot_fsinfo *fsinfo;
1668 struct buffer_head *fsinfo_bh;
1669
1670 /* Must be FAT32 */
1671 sbi->fat_bits = 32;
1672 sbi->fat_length = bpb.fat32_length;
1673 sbi->root_cluster = bpb.fat32_root_cluster;
1674
1675 /* MC - if info_sector is 0, don't multiply by 0 */
1676 sbi->fsinfo_sector = bpb.fat32_info_sector;
1677 if (sbi->fsinfo_sector == 0)
1678 sbi->fsinfo_sector = 1;
1679
1680 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1681 if (fsinfo_bh == NULL) {
1682 fat_msg(sb, KERN_ERR, "bread failed, FSINFO block"
1683 " (sector = %lu)", sbi->fsinfo_sector);
1684 goto out_fail;
1685 }
1686
1687 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1688 if (!IS_FSINFO(fsinfo)) {
1689 fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: "
1690 "0x%08x, 0x%08x (sector = %lu)",
1691 le32_to_cpu(fsinfo->signature1),
1692 le32_to_cpu(fsinfo->signature2),
1693 sbi->fsinfo_sector);
1694 } else {
1695 if (sbi->options.usefree)
1696 sbi->free_clus_valid = 1;
1697 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1698 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1699 }
1700
1701 brelse(fsinfo_bh);
1702 }
1703
1704 /* interpret volume ID as a little endian 32 bit integer */
1705 if (is_fat32(sbi))
1706 sbi->vol_id = bpb.fat32_vol_id;
1707 else /* fat 16 or 12 */
1708 sbi->vol_id = bpb.fat16_vol_id;
1709
1710 __le32 vol_id_le = cpu_to_le32(sbi->vol_id);
1711 super_set_uuid(sb, (void *) &vol_id_le, sizeof(vol_id_le));
1712
1713 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1714 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1715
1716 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1717 sbi->dir_entries = bpb.fat_dir_entries;
1718 if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1719 if (!silent)
1720 fat_msg(sb, KERN_ERR, "bogus number of directory entries"
1721 " (%u)", sbi->dir_entries);
1722 goto out_invalid;
1723 }
1724
1725 rootdir_sectors = sbi->dir_entries
1726 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1727 sbi->data_start = sbi->dir_start + rootdir_sectors;
1728 total_sectors = bpb.fat_sectors;
1729 if (total_sectors == 0)
1730 total_sectors = bpb.fat_total_sect;
1731
1732 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1733
1734 if (!is_fat32(sbi))
1735 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1736
1737 /* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
1738 if (is_fat32(sbi))
1739 sbi->dirty = bpb.fat32_state & FAT_STATE_DIRTY;
1740 else /* fat 16 or 12 */
1741 sbi->dirty = bpb.fat16_state & FAT_STATE_DIRTY;
1742
1743 /* check that FAT table does not overflow */
1744 fat_clusters = calc_fat_clusters(sb);
1745 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1746 if (total_clusters > max_fat(sb)) {
1747 if (!silent)
1748 fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
1749 total_clusters);
1750 goto out_invalid;
1751 }
1752
1753 sbi->max_cluster = total_clusters + FAT_START_ENT;
1754 /* check the free_clusters, it's not necessarily correct */
1755 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1756 sbi->free_clusters = -1;
1757 /* check the prev_free, it's not necessarily correct */
1758 sbi->prev_free %= sbi->max_cluster;
1759 if (sbi->prev_free < FAT_START_ENT)
1760 sbi->prev_free = FAT_START_ENT;
1761
1762 /* set up enough so that it can read an inode */
1763 fat_hash_init(sb);
1764 dir_hash_init(sb);
1765 fat_ent_access_init(sb);
1766
1767 /*
1768 * The low byte of the first FAT entry must have the same value as
1769 * the media field of the boot sector. But in real world, too many
1770 * devices are writing wrong values. So, removed that validity check.
1771 *
1772 * The removed check compared the first FAT entry to a value dependent
1773 * on the media field like this:
1774 * == (0x0F00 | media), for FAT12
1775 * == (0XFF00 | media), for FAT16
1776 * == (0x0FFFFF | media), for FAT32
1777 */
1778
1779 error = -EINVAL;
1780 sprintf(buf, "cp%d", sbi->options.codepage);
1781 sbi->nls_disk = load_nls(buf);
1782 if (!sbi->nls_disk) {
1783 fat_msg(sb, KERN_ERR, "codepage %s not found", buf);
1784 goto out_fail;
1785 }
1786
1787 /* FIXME: utf8 is using iocharset for upper/lower conversion */
1788 if (sbi->options.isvfat) {
1789 sbi->nls_io = load_nls(sbi->options.iocharset);
1790 if (!sbi->nls_io) {
1791 fat_msg(sb, KERN_ERR, "IO charset %s not found",
1792 sbi->options.iocharset);
1793 goto out_fail;
1794 }
1795 }
1796
1797 error = -ENOMEM;
1798 fat_inode = new_inode(sb);
1799 if (!fat_inode)
1800 goto out_fail;
1801 sbi->fat_inode = fat_inode;
1802
1803 fsinfo_inode = new_inode(sb);
1804 if (!fsinfo_inode)
1805 goto out_fail;
1806 fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
1807 sbi->fsinfo_inode = fsinfo_inode;
1808 insert_inode_hash(fsinfo_inode);
1809
1810 root_inode = new_inode(sb);
1811 if (!root_inode)
1812 goto out_fail;
1813 root_inode->i_ino = MSDOS_ROOT_INO;
1814 inode_set_iversion(root_inode, 1);
1815 error = fat_read_root(root_inode);
1816 if (error < 0) {
1817 iput(root_inode);
1818 goto out_fail;
1819 }
1820 error = -ENOMEM;
1821 insert_inode_hash(root_inode);
1822 fat_attach(root_inode, 0);
1823 sb->s_root = d_make_root(root_inode);
1824 if (!sb->s_root) {
1825 fat_msg(sb, KERN_ERR, "get root inode failed");
1826 goto out_fail;
1827 }
1828
1829 if (sbi->options.discard && !bdev_max_discard_sectors(sb->s_bdev))
1830 fat_msg(sb, KERN_WARNING,
1831 "mounting with \"discard\" option, but the device does not support discard");
1832
1833 fat_set_state(sb, 1, 0);
1834 return 0;
1835
1836 out_invalid:
1837 error = -EINVAL;
1838 if (!silent)
1839 fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem");
1840
1841 out_fail:
1842 iput(fsinfo_inode);
1843 iput(fat_inode);
1844 unload_nls(sbi->nls_io);
1845 unload_nls(sbi->nls_disk);
1846 fat_reset_iocharset(&sbi->options);
1847 sb->s_fs_info = NULL;
1848 kfree(sbi);
1849 return error;
1850 }
1851
1852 EXPORT_SYMBOL_GPL(fat_fill_super);
1853
1854 /*
1855 * helper function for fat_flush_inodes. This writes both the inode
1856 * and the file data blocks, waiting for in flight data blocks before
1857 * the start of the call. It does not wait for any io started
1858 * during the call
1859 */
1860 static int writeback_inode(struct inode *inode)
1861 {
1862
1863 int ret;
1864
1865 /* if we used wait=1, sync_inode_metadata waits for the io for the
1866 * inode to finish. So wait=0 is sent down to sync_inode_metadata
1867 * and filemap_fdatawrite is used for the data blocks
1868 */
1869 ret = sync_inode_metadata(inode, 0);
1870 if (!ret)
1871 ret = filemap_fdatawrite(inode->i_mapping);
1872 return ret;
1873 }
1874
1875 /*
1876 * write data and metadata corresponding to i1 and i2. The io is
1877 * started but we do not wait for any of it to finish.
1878 *
1879 * filemap_flush is used for the block device, so if there is a dirty
1880 * page for a block already in flight, we will not wait and start the
1881 * io over again
1882 */
1883 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1884 {
1885 int ret = 0;
1886 if (!MSDOS_SB(sb)->options.flush)
1887 return 0;
1888 if (i1)
1889 ret = writeback_inode(i1);
1890 if (!ret && i2)
1891 ret = writeback_inode(i2);
1892 if (!ret)
1893 ret = sync_blockdev_nowait(sb->s_bdev);
1894 return ret;
1895 }
1896 EXPORT_SYMBOL_GPL(fat_flush_inodes);
1897
1898 int fat_init_fs_context(struct fs_context *fc, bool is_vfat)
1899 {
1900 struct fat_mount_options *opts;
1901
1902 opts = kzalloc(sizeof(*opts), GFP_KERNEL);
1903 if (!opts)
1904 return -ENOMEM;
1905
1906 opts->isvfat = is_vfat;
1907 opts->fs_uid = current_uid();
1908 opts->fs_gid = current_gid();
1909 opts->fs_fmask = opts->fs_dmask = current_umask();
1910 opts->allow_utime = -1;
1911 opts->codepage = fat_default_codepage;
1912 fat_reset_iocharset(opts);
1913 if (is_vfat) {
1914 opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95;
1915 opts->rodir = 0;
1916 } else {
1917 opts->shortname = 0;
1918 opts->rodir = 1;
1919 }
1920 opts->name_check = 'n';
1921 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0;
1922 opts->unicode_xlate = 0;
1923 opts->numtail = 1;
1924 opts->usefree = opts->nocase = 0;
1925 opts->tz_set = 0;
1926 opts->nfs = 0;
1927 opts->errors = FAT_ERRORS_RO;
1928 opts->debug = 0;
1929
1930 opts->utf8 = IS_ENABLED(CONFIG_FAT_DEFAULT_UTF8) && is_vfat;
1931
1932 fc->fs_private = opts;
1933 /* fc->ops assigned by caller */
1934
1935 return 0;
1936 }
1937 EXPORT_SYMBOL_GPL(fat_init_fs_context);
1938
1939 void fat_free_fc(struct fs_context *fc)
1940 {
1941 struct fat_mount_options *opts = fc->fs_private;
1942
1943 if (opts->iocharset != fat_default_iocharset)
1944 kfree(opts->iocharset);
1945 kfree(fc->fs_private);
1946 }
1947 EXPORT_SYMBOL_GPL(fat_free_fc);
1948
1949 static int __init init_fat_fs(void)
1950 {
1951 int err;
1952
1953 err = fat_cache_init();
1954 if (err)
1955 return err;
1956
1957 err = fat_init_inodecache();
1958 if (err)
1959 goto failed;
1960
1961 return 0;
1962
1963 failed:
1964 fat_cache_destroy();
1965 return err;
1966 }
1967
1968 static void __exit exit_fat_fs(void)
1969 {
1970 fat_cache_destroy();
1971 fat_destroy_inodecache();
1972 }
1973
1974 module_init(init_fat_fs)
1975 module_exit(exit_fat_fs)
1976
1977 MODULE_DESCRIPTION("Core FAT filesystem support");
1978 MODULE_LICENSE("GPL");
1979
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