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/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 /* if user don't select VFAT, this is undefined. */
30 #define CONFIG_FAT_DEFAULT_IOCHARSET ""
31 #endif
32
33 #define KB_IN_SECTORS 2
34
35 /* DOS dates from 1980/1/1 through 2107/12/31 */
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 * A deserialized copy of the on-disk structure laid out in struct
42 * fat_boot_sector.
43 */
44 struct 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
64 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
65 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
66
67 static 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
fat_add_cluster(struct inode * inode)104 int 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 /* FIXME: this cluster should be added after data of this
112 * cluster is writed */
113 err = fat_chain_add(inode, cluster, 1);
114 if (err)
115 fat_free_clusters(inode, cluster);
116 return err;
117 }
118
__fat_get_block(struct inode * inode,sector_t iblock,unsigned long * max_blocks,struct buffer_head * bh_result,int create)119 static 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 * allocate a cluster according to the following.
150 * 1) no more available blocks
151 * 2) not part of fallocate region
152 */
153 if (!offset && !(iblock < last_block)) {
154 /* TODO: multiple cluster allocation would be desirable. */
155 err = fat_add_cluster(inode);
156 if (err)
157 return err;
158 }
159 /* available blocks on this cluster */
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
fat_get_block(struct inode * inode,sector_t iblock,struct buffer_head * bh_result,int create)183 static 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
fat_writepages(struct address_space * mapping,struct writeback_control * wbc)197 static int fat_writepages(struct address_space *mapping,
198 struct writeback_control *wbc)
199 {
200 return mpage_writepages(mapping, wbc, fat_get_block);
201 }
202
fat_read_folio(struct file * file,struct folio * folio)203 static int fat_read_folio(struct file *file, struct folio *folio)
204 {
205 return mpage_read_folio(folio, fat_get_block);
206 }
207
fat_readahead(struct readahead_control * rac)208 static void fat_readahead(struct readahead_control *rac)
209 {
210 mpage_readahead(rac, fat_get_block);
211 }
212
fat_write_failed(struct address_space * mapping,loff_t to)213 static void fat_write_failed(struct address_space *mapping, loff_t to)
214 {
215 struct inode *inode = mapping->host;
216
217 if (to > inode->i_size) {
218 truncate_pagecache(inode, inode->i_size);
219 fat_truncate_blocks(inode, inode->i_size);
220 }
221 }
222
fat_write_begin(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,struct page ** pagep,void ** fsdata)223 static int fat_write_begin(struct file *file, struct address_space *mapping,
224 loff_t pos, unsigned len,
225 struct page **pagep, void **fsdata)
226 {
227 int err;
228
229 *pagep = NULL;
230 err = cont_write_begin(file, mapping, pos, len,
231 pagep, fsdata, fat_get_block,
232 &MSDOS_I(mapping->host)->mmu_private);
233 if (err < 0)
234 fat_write_failed(mapping, pos + len);
235 return err;
236 }
237
fat_write_end(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct page * pagep,void * fsdata)238 static int fat_write_end(struct file *file, struct address_space *mapping,
239 loff_t pos, unsigned len, unsigned copied,
240 struct page *pagep, void *fsdata)
241 {
242 struct inode *inode = mapping->host;
243 int err;
244 err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
245 if (err < len)
246 fat_write_failed(mapping, pos + len);
247 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
248 fat_truncate_time(inode, NULL, S_CTIME|S_MTIME);
249 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
250 mark_inode_dirty(inode);
251 }
252 return err;
253 }
254
fat_direct_IO(struct kiocb * iocb,struct iov_iter * iter)255 static ssize_t fat_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
256 {
257 struct file *file = iocb->ki_filp;
258 struct address_space *mapping = file->f_mapping;
259 struct inode *inode = mapping->host;
260 size_t count = iov_iter_count(iter);
261 loff_t offset = iocb->ki_pos;
262 ssize_t ret;
263
264 if (iov_iter_rw(iter) == WRITE) {
265 /*
266 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
267 * so we need to update the ->mmu_private to block boundary.
268 *
269 * But we must fill the remaining area or hole by nul for
270 * updating ->mmu_private.
271 *
272 * Return 0, and fallback to normal buffered write.
273 */
274 loff_t size = offset + count;
275 if (MSDOS_I(inode)->mmu_private < size)
276 return 0;
277 }
278
279 /*
280 * FAT need to use the DIO_LOCKING for avoiding the race
281 * condition of fat_get_block() and ->truncate().
282 */
283 ret = blockdev_direct_IO(iocb, inode, iter, fat_get_block);
284 if (ret < 0 && iov_iter_rw(iter) == WRITE)
285 fat_write_failed(mapping, offset + count);
286
287 return ret;
288 }
289
fat_get_block_bmap(struct inode * inode,sector_t iblock,struct buffer_head * bh_result,int create)290 static int fat_get_block_bmap(struct inode *inode, sector_t iblock,
291 struct buffer_head *bh_result, int create)
292 {
293 struct super_block *sb = inode->i_sb;
294 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
295 int err;
296 sector_t bmap;
297 unsigned long mapped_blocks;
298
299 BUG_ON(create != 0);
300
301 err = fat_bmap(inode, iblock, &bmap, &mapped_blocks, create, true);
302 if (err)
303 return err;
304
305 if (bmap) {
306 map_bh(bh_result, sb, bmap);
307 max_blocks = min(mapped_blocks, max_blocks);
308 }
309
310 bh_result->b_size = max_blocks << sb->s_blocksize_bits;
311
312 return 0;
313 }
314
_fat_bmap(struct address_space * mapping,sector_t block)315 static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
316 {
317 sector_t blocknr;
318
319 /* fat_get_cluster() assumes the requested blocknr isn't truncated. */
320 down_read(&MSDOS_I(mapping->host)->truncate_lock);
321 blocknr = generic_block_bmap(mapping, block, fat_get_block_bmap);
322 up_read(&MSDOS_I(mapping->host)->truncate_lock);
323
324 return blocknr;
325 }
326
327 /*
328 * fat_block_truncate_page() zeroes out a mapping from file offset `from'
329 * up to the end of the block which corresponds to `from'.
330 * This is required during truncate to physically zeroout the tail end
331 * of that block so it doesn't yield old data if the file is later grown.
332 * Also, avoid causing failure from fsx for cases of "data past EOF"
333 */
fat_block_truncate_page(struct inode * inode,loff_t from)334 int fat_block_truncate_page(struct inode *inode, loff_t from)
335 {
336 return block_truncate_page(inode->i_mapping, from, fat_get_block);
337 }
338
339 static const struct address_space_operations fat_aops = {
340 .dirty_folio = block_dirty_folio,
341 .invalidate_folio = block_invalidate_folio,
342 .read_folio = fat_read_folio,
343 .readahead = fat_readahead,
344 .writepages = fat_writepages,
345 .write_begin = fat_write_begin,
346 .write_end = fat_write_end,
347 .direct_IO = fat_direct_IO,
348 .bmap = _fat_bmap,
349 .migrate_folio = buffer_migrate_folio,
350 };
351
352 /*
353 * New FAT inode stuff. We do the following:
354 * a) i_ino is constant and has nothing with on-disk location.
355 * b) FAT manages its own cache of directory entries.
356 * c) *This* cache is indexed by on-disk location.
357 * d) inode has an associated directory entry, all right, but
358 * it may be unhashed.
359 * e) currently entries are stored within struct inode. That should
360 * change.
361 * f) we deal with races in the following way:
362 * 1. readdir() and lookup() do FAT-dir-cache lookup.
363 * 2. rename() unhashes the F-d-c entry and rehashes it in
364 * a new place.
365 * 3. unlink() and rmdir() unhash F-d-c entry.
366 * 4. fat_write_inode() checks whether the thing is unhashed.
367 * If it is we silently return. If it isn't we do bread(),
368 * check if the location is still valid and retry if it
369 * isn't. Otherwise we do changes.
370 * 5. Spinlock is used to protect hash/unhash/location check/lookup
371 * 6. fat_evict_inode() unhashes the F-d-c entry.
372 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry
373 * and consider negative result as cache miss.
374 */
375
fat_hash_init(struct super_block * sb)376 static void fat_hash_init(struct super_block *sb)
377 {
378 struct msdos_sb_info *sbi = MSDOS_SB(sb);
379 int i;
380
381 spin_lock_init(&sbi->inode_hash_lock);
382 for (i = 0; i < FAT_HASH_SIZE; i++)
383 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
384 }
385
fat_hash(loff_t i_pos)386 static inline unsigned long fat_hash(loff_t i_pos)
387 {
388 return hash_32(i_pos, FAT_HASH_BITS);
389 }
390
dir_hash_init(struct super_block * sb)391 static void dir_hash_init(struct super_block *sb)
392 {
393 struct msdos_sb_info *sbi = MSDOS_SB(sb);
394 int i;
395
396 spin_lock_init(&sbi->dir_hash_lock);
397 for (i = 0; i < FAT_HASH_SIZE; i++)
398 INIT_HLIST_HEAD(&sbi->dir_hashtable[i]);
399 }
400
fat_attach(struct inode * inode,loff_t i_pos)401 void fat_attach(struct inode *inode, loff_t i_pos)
402 {
403 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
404
405 if (inode->i_ino != MSDOS_ROOT_INO) {
406 struct hlist_head *head = sbi->inode_hashtable
407 + fat_hash(i_pos);
408
409 spin_lock(&sbi->inode_hash_lock);
410 MSDOS_I(inode)->i_pos = i_pos;
411 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
412 spin_unlock(&sbi->inode_hash_lock);
413 }
414
415 /* If NFS support is enabled, cache the mapping of start cluster
416 * to directory inode. This is used during reconnection of
417 * dentries to the filesystem root.
418 */
419 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
420 struct hlist_head *d_head = sbi->dir_hashtable;
421 d_head += fat_dir_hash(MSDOS_I(inode)->i_logstart);
422
423 spin_lock(&sbi->dir_hash_lock);
424 hlist_add_head(&MSDOS_I(inode)->i_dir_hash, d_head);
425 spin_unlock(&sbi->dir_hash_lock);
426 }
427 }
428 EXPORT_SYMBOL_GPL(fat_attach);
429
fat_detach(struct inode * inode)430 void fat_detach(struct inode *inode)
431 {
432 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
433 spin_lock(&sbi->inode_hash_lock);
434 MSDOS_I(inode)->i_pos = 0;
435 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
436 spin_unlock(&sbi->inode_hash_lock);
437
438 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
439 spin_lock(&sbi->dir_hash_lock);
440 hlist_del_init(&MSDOS_I(inode)->i_dir_hash);
441 spin_unlock(&sbi->dir_hash_lock);
442 }
443 }
444 EXPORT_SYMBOL_GPL(fat_detach);
445
fat_iget(struct super_block * sb,loff_t i_pos)446 struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
447 {
448 struct msdos_sb_info *sbi = MSDOS_SB(sb);
449 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
450 struct msdos_inode_info *i;
451 struct inode *inode = NULL;
452
453 spin_lock(&sbi->inode_hash_lock);
454 hlist_for_each_entry(i, head, i_fat_hash) {
455 BUG_ON(i->vfs_inode.i_sb != sb);
456 if (i->i_pos != i_pos)
457 continue;
458 inode = igrab(&i->vfs_inode);
459 if (inode)
460 break;
461 }
462 spin_unlock(&sbi->inode_hash_lock);
463 return inode;
464 }
465
is_exec(unsigned char * extension)466 static int is_exec(unsigned char *extension)
467 {
468 unsigned char exe_extensions[] = "EXECOMBAT", *walk;
469
470 for (walk = exe_extensions; *walk; walk += 3)
471 if (!strncmp(extension, walk, 3))
472 return 1;
473 return 0;
474 }
475
fat_calc_dir_size(struct inode * inode)476 static int fat_calc_dir_size(struct inode *inode)
477 {
478 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
479 int ret, fclus, dclus;
480
481 inode->i_size = 0;
482 if (MSDOS_I(inode)->i_start == 0)
483 return 0;
484
485 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
486 if (ret < 0)
487 return ret;
488 inode->i_size = (fclus + 1) << sbi->cluster_bits;
489
490 return 0;
491 }
492
fat_validate_dir(struct inode * dir)493 static int fat_validate_dir(struct inode *dir)
494 {
495 struct super_block *sb = dir->i_sb;
496
497 if (dir->i_nlink < 2) {
498 /* Directory should have "."/".." entries at least. */
499 fat_fs_error(sb, "corrupted directory (invalid entries)");
500 return -EIO;
501 }
502 if (MSDOS_I(dir)->i_start == 0 ||
503 MSDOS_I(dir)->i_start == MSDOS_SB(sb)->root_cluster) {
504 /* Directory should point valid cluster. */
505 fat_fs_error(sb, "corrupted directory (invalid i_start)");
506 return -EIO;
507 }
508 return 0;
509 }
510
511 /* doesn't deal with root inode */
fat_fill_inode(struct inode * inode,struct msdos_dir_entry * de)512 int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
513 {
514 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
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, &inode->i_mtime, de->time, de->date, 0);
565 inode_set_ctime_to_ts(inode, inode->i_mtime);
566 if (sbi->options.isvfat) {
567 fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
568 fat_time_fat2unix(sbi, &MSDOS_I(inode)->i_crtime, de->ctime,
569 de->cdate, de->ctime_cs);
570 } else
571 inode->i_atime = fat_truncate_atime(sbi, &inode->i_mtime);
572
573 return 0;
574 }
575
fat_lock_build_inode(struct msdos_sb_info * sbi)576 static inline void fat_lock_build_inode(struct msdos_sb_info *sbi)
577 {
578 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
579 mutex_lock(&sbi->nfs_build_inode_lock);
580 }
581
fat_unlock_build_inode(struct msdos_sb_info * sbi)582 static inline void fat_unlock_build_inode(struct msdos_sb_info *sbi)
583 {
584 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
585 mutex_unlock(&sbi->nfs_build_inode_lock);
586 }
587
fat_build_inode(struct super_block * sb,struct msdos_dir_entry * de,loff_t i_pos)588 struct inode *fat_build_inode(struct super_block *sb,
589 struct msdos_dir_entry *de, loff_t i_pos)
590 {
591 struct inode *inode;
592 int err;
593
594 fat_lock_build_inode(MSDOS_SB(sb));
595 inode = fat_iget(sb, i_pos);
596 if (inode)
597 goto out;
598 inode = new_inode(sb);
599 if (!inode) {
600 inode = ERR_PTR(-ENOMEM);
601 goto out;
602 }
603 inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
604 inode_set_iversion(inode, 1);
605 err = fat_fill_inode(inode, de);
606 if (err) {
607 iput(inode);
608 inode = ERR_PTR(err);
609 goto out;
610 }
611 fat_attach(inode, i_pos);
612 insert_inode_hash(inode);
613 out:
614 fat_unlock_build_inode(MSDOS_SB(sb));
615 return inode;
616 }
617
618 EXPORT_SYMBOL_GPL(fat_build_inode);
619
620 static int __fat_write_inode(struct inode *inode, int wait);
621
fat_free_eofblocks(struct inode * inode)622 static void fat_free_eofblocks(struct inode *inode)
623 {
624 /* Release unwritten fallocated blocks on inode eviction. */
625 if ((inode->i_blocks << 9) >
626 round_up(MSDOS_I(inode)->mmu_private,
627 MSDOS_SB(inode->i_sb)->cluster_size)) {
628 int err;
629
630 fat_truncate_blocks(inode, MSDOS_I(inode)->mmu_private);
631 /* Fallocate results in updating the i_start/iogstart
632 * for the zero byte file. So, make it return to
633 * original state during evict and commit it to avoid
634 * any corruption on the next access to the cluster
635 * chain for the file.
636 */
637 err = __fat_write_inode(inode, inode_needs_sync(inode));
638 if (err) {
639 fat_msg(inode->i_sb, KERN_WARNING, "Failed to "
640 "update on disk inode for unused "
641 "fallocated blocks, inode could be "
642 "corrupted. Please run fsck");
643 }
644
645 }
646 }
647
fat_evict_inode(struct inode * inode)648 static void fat_evict_inode(struct inode *inode)
649 {
650 truncate_inode_pages_final(&inode->i_data);
651 if (!inode->i_nlink) {
652 inode->i_size = 0;
653 fat_truncate_blocks(inode, 0);
654 } else
655 fat_free_eofblocks(inode);
656
657 invalidate_inode_buffers(inode);
658 clear_inode(inode);
659 fat_cache_inval_inode(inode);
660 fat_detach(inode);
661 }
662
fat_set_state(struct super_block * sb,unsigned int set,unsigned int force)663 static void fat_set_state(struct super_block *sb,
664 unsigned int set, unsigned int force)
665 {
666 struct buffer_head *bh;
667 struct fat_boot_sector *b;
668 struct msdos_sb_info *sbi = MSDOS_SB(sb);
669
670 /* do not change any thing if mounted read only */
671 if (sb_rdonly(sb) && !force)
672 return;
673
674 /* do not change state if fs was dirty */
675 if (sbi->dirty) {
676 /* warn only on set (mount). */
677 if (set)
678 fat_msg(sb, KERN_WARNING, "Volume was not properly "
679 "unmounted. Some data may be corrupt. "
680 "Please run fsck.");
681 return;
682 }
683
684 bh = sb_bread(sb, 0);
685 if (bh == NULL) {
686 fat_msg(sb, KERN_ERR, "unable to read boot sector "
687 "to mark fs as dirty");
688 return;
689 }
690
691 b = (struct fat_boot_sector *) bh->b_data;
692
693 if (is_fat32(sbi)) {
694 if (set)
695 b->fat32.state |= FAT_STATE_DIRTY;
696 else
697 b->fat32.state &= ~FAT_STATE_DIRTY;
698 } else /* fat 16 and 12 */ {
699 if (set)
700 b->fat16.state |= FAT_STATE_DIRTY;
701 else
702 b->fat16.state &= ~FAT_STATE_DIRTY;
703 }
704
705 mark_buffer_dirty(bh);
706 sync_dirty_buffer(bh);
707 brelse(bh);
708 }
709
fat_reset_iocharset(struct fat_mount_options * opts)710 static void fat_reset_iocharset(struct fat_mount_options *opts)
711 {
712 if (opts->iocharset != fat_default_iocharset) {
713 /* Note: opts->iocharset can be NULL here */
714 kfree(opts->iocharset);
715 opts->iocharset = fat_default_iocharset;
716 }
717 }
718
delayed_free(struct rcu_head * p)719 static void delayed_free(struct rcu_head *p)
720 {
721 struct msdos_sb_info *sbi = container_of(p, struct msdos_sb_info, rcu);
722 unload_nls(sbi->nls_disk);
723 unload_nls(sbi->nls_io);
724 fat_reset_iocharset(&sbi->options);
725 kfree(sbi);
726 }
727
fat_put_super(struct super_block * sb)728 static void fat_put_super(struct super_block *sb)
729 {
730 struct msdos_sb_info *sbi = MSDOS_SB(sb);
731
732 fat_set_state(sb, 0, 0);
733
734 iput(sbi->fsinfo_inode);
735 iput(sbi->fat_inode);
736
737 call_rcu(&sbi->rcu, delayed_free);
738 }
739
740 static struct kmem_cache *fat_inode_cachep;
741
fat_alloc_inode(struct super_block * sb)742 static struct inode *fat_alloc_inode(struct super_block *sb)
743 {
744 struct msdos_inode_info *ei;
745 ei = alloc_inode_sb(sb, fat_inode_cachep, GFP_NOFS);
746 if (!ei)
747 return NULL;
748
749 init_rwsem(&ei->truncate_lock);
750 /* Zeroing to allow iput() even if partial initialized inode. */
751 ei->mmu_private = 0;
752 ei->i_start = 0;
753 ei->i_logstart = 0;
754 ei->i_attrs = 0;
755 ei->i_pos = 0;
756 ei->i_crtime.tv_sec = 0;
757 ei->i_crtime.tv_nsec = 0;
758
759 return &ei->vfs_inode;
760 }
761
fat_free_inode(struct inode * inode)762 static void fat_free_inode(struct inode *inode)
763 {
764 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
765 }
766
init_once(void * foo)767 static void init_once(void *foo)
768 {
769 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
770
771 spin_lock_init(&ei->cache_lru_lock);
772 ei->nr_caches = 0;
773 ei->cache_valid_id = FAT_CACHE_VALID + 1;
774 INIT_LIST_HEAD(&ei->cache_lru);
775 INIT_HLIST_NODE(&ei->i_fat_hash);
776 INIT_HLIST_NODE(&ei->i_dir_hash);
777 inode_init_once(&ei->vfs_inode);
778 }
779
fat_init_inodecache(void)780 static int __init fat_init_inodecache(void)
781 {
782 fat_inode_cachep = kmem_cache_create("fat_inode_cache",
783 sizeof(struct msdos_inode_info),
784 0, (SLAB_RECLAIM_ACCOUNT|
785 SLAB_MEM_SPREAD|SLAB_ACCOUNT),
786 init_once);
787 if (fat_inode_cachep == NULL)
788 return -ENOMEM;
789 return 0;
790 }
791
fat_destroy_inodecache(void)792 static void __exit fat_destroy_inodecache(void)
793 {
794 /*
795 * Make sure all delayed rcu free inodes are flushed before we
796 * destroy cache.
797 */
798 rcu_barrier();
799 kmem_cache_destroy(fat_inode_cachep);
800 }
801
fat_remount(struct super_block * sb,int * flags,char * data)802 static int fat_remount(struct super_block *sb, int *flags, char *data)
803 {
804 bool new_rdonly;
805 struct msdos_sb_info *sbi = MSDOS_SB(sb);
806 *flags |= SB_NODIRATIME | (sbi->options.isvfat ? 0 : SB_NOATIME);
807
808 sync_filesystem(sb);
809
810 /* make sure we update state on remount. */
811 new_rdonly = *flags & SB_RDONLY;
812 if (new_rdonly != sb_rdonly(sb)) {
813 if (new_rdonly)
814 fat_set_state(sb, 0, 0);
815 else
816 fat_set_state(sb, 1, 1);
817 }
818 return 0;
819 }
820
fat_statfs(struct dentry * dentry,struct kstatfs * buf)821 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
822 {
823 struct super_block *sb = dentry->d_sb;
824 struct msdos_sb_info *sbi = MSDOS_SB(sb);
825 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
826
827 /* If the count of free cluster is still unknown, counts it here. */
828 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
829 int err = fat_count_free_clusters(dentry->d_sb);
830 if (err)
831 return err;
832 }
833
834 buf->f_type = dentry->d_sb->s_magic;
835 buf->f_bsize = sbi->cluster_size;
836 buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
837 buf->f_bfree = sbi->free_clusters;
838 buf->f_bavail = sbi->free_clusters;
839 buf->f_fsid = u64_to_fsid(id);
840 buf->f_namelen =
841 (sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE;
842
843 return 0;
844 }
845
__fat_write_inode(struct inode * inode,int wait)846 static int __fat_write_inode(struct inode *inode, int wait)
847 {
848 struct super_block *sb = inode->i_sb;
849 struct msdos_sb_info *sbi = MSDOS_SB(sb);
850 struct buffer_head *bh;
851 struct msdos_dir_entry *raw_entry;
852 loff_t i_pos;
853 sector_t blocknr;
854 int err, offset;
855
856 if (inode->i_ino == MSDOS_ROOT_INO)
857 return 0;
858
859 retry:
860 i_pos = fat_i_pos_read(sbi, inode);
861 if (!i_pos)
862 return 0;
863
864 fat_get_blknr_offset(sbi, i_pos, &blocknr, &offset);
865 bh = sb_bread(sb, blocknr);
866 if (!bh) {
867 fat_msg(sb, KERN_ERR, "unable to read inode block "
868 "for updating (i_pos %lld)", i_pos);
869 return -EIO;
870 }
871 spin_lock(&sbi->inode_hash_lock);
872 if (i_pos != MSDOS_I(inode)->i_pos) {
873 spin_unlock(&sbi->inode_hash_lock);
874 brelse(bh);
875 goto retry;
876 }
877
878 raw_entry = &((struct msdos_dir_entry *) (bh->b_data))[offset];
879 if (S_ISDIR(inode->i_mode))
880 raw_entry->size = 0;
881 else
882 raw_entry->size = cpu_to_le32(inode->i_size);
883 raw_entry->attr = fat_make_attrs(inode);
884 fat_set_start(raw_entry, MSDOS_I(inode)->i_logstart);
885 fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
886 &raw_entry->date, NULL);
887 if (sbi->options.isvfat) {
888 __le16 atime;
889 fat_time_unix2fat(sbi, &inode->i_atime, &atime,
890 &raw_entry->adate, NULL);
891 fat_time_unix2fat(sbi, &MSDOS_I(inode)->i_crtime, &raw_entry->ctime,
892 &raw_entry->cdate, &raw_entry->ctime_cs);
893 }
894 spin_unlock(&sbi->inode_hash_lock);
895 mark_buffer_dirty(bh);
896 err = 0;
897 if (wait)
898 err = sync_dirty_buffer(bh);
899 brelse(bh);
900 return err;
901 }
902
fat_write_inode(struct inode * inode,struct writeback_control * wbc)903 static int fat_write_inode(struct inode *inode, struct writeback_control *wbc)
904 {
905 int err;
906
907 if (inode->i_ino == MSDOS_FSINFO_INO) {
908 struct super_block *sb = inode->i_sb;
909
910 mutex_lock(&MSDOS_SB(sb)->s_lock);
911 err = fat_clusters_flush(sb);
912 mutex_unlock(&MSDOS_SB(sb)->s_lock);
913 } else
914 err = __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
915
916 return err;
917 }
918
fat_sync_inode(struct inode * inode)919 int fat_sync_inode(struct inode *inode)
920 {
921 return __fat_write_inode(inode, 1);
922 }
923
924 EXPORT_SYMBOL_GPL(fat_sync_inode);
925
926 static int fat_show_options(struct seq_file *m, struct dentry *root);
927 static const struct super_operations fat_sops = {
928 .alloc_inode = fat_alloc_inode,
929 .free_inode = fat_free_inode,
930 .write_inode = fat_write_inode,
931 .evict_inode = fat_evict_inode,
932 .put_super = fat_put_super,
933 .statfs = fat_statfs,
934 .remount_fs = fat_remount,
935
936 .show_options = fat_show_options,
937 };
938
fat_show_options(struct seq_file * m,struct dentry * root)939 static int fat_show_options(struct seq_file *m, struct dentry *root)
940 {
941 struct msdos_sb_info *sbi = MSDOS_SB(root->d_sb);
942 struct fat_mount_options *opts = &sbi->options;
943 int isvfat = opts->isvfat;
944
945 if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
946 seq_printf(m, ",uid=%u",
947 from_kuid_munged(&init_user_ns, opts->fs_uid));
948 if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
949 seq_printf(m, ",gid=%u",
950 from_kgid_munged(&init_user_ns, opts->fs_gid));
951 seq_printf(m, ",fmask=%04o", opts->fs_fmask);
952 seq_printf(m, ",dmask=%04o", opts->fs_dmask);
953 if (opts->allow_utime)
954 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
955 if (sbi->nls_disk)
956 /* strip "cp" prefix from displayed option */
957 seq_printf(m, ",codepage=%s", &sbi->nls_disk->charset[2]);
958 if (isvfat) {
959 if (sbi->nls_io)
960 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
961
962 switch (opts->shortname) {
963 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
964 seq_puts(m, ",shortname=win95");
965 break;
966 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
967 seq_puts(m, ",shortname=winnt");
968 break;
969 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
970 seq_puts(m, ",shortname=mixed");
971 break;
972 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
973 seq_puts(m, ",shortname=lower");
974 break;
975 default:
976 seq_puts(m, ",shortname=unknown");
977 break;
978 }
979 }
980 if (opts->name_check != 'n')
981 seq_printf(m, ",check=%c", opts->name_check);
982 if (opts->usefree)
983 seq_puts(m, ",usefree");
984 if (opts->quiet)
985 seq_puts(m, ",quiet");
986 if (opts->showexec)
987 seq_puts(m, ",showexec");
988 if (opts->sys_immutable)
989 seq_puts(m, ",sys_immutable");
990 if (!isvfat) {
991 if (opts->dotsOK)
992 seq_puts(m, ",dotsOK=yes");
993 if (opts->nocase)
994 seq_puts(m, ",nocase");
995 } else {
996 if (opts->utf8)
997 seq_puts(m, ",utf8");
998 if (opts->unicode_xlate)
999 seq_puts(m, ",uni_xlate");
1000 if (!opts->numtail)
1001 seq_puts(m, ",nonumtail");
1002 if (opts->rodir)
1003 seq_puts(m, ",rodir");
1004 }
1005 if (opts->flush)
1006 seq_puts(m, ",flush");
1007 if (opts->tz_set) {
1008 if (opts->time_offset)
1009 seq_printf(m, ",time_offset=%d", opts->time_offset);
1010 else
1011 seq_puts(m, ",tz=UTC");
1012 }
1013 if (opts->errors == FAT_ERRORS_CONT)
1014 seq_puts(m, ",errors=continue");
1015 else if (opts->errors == FAT_ERRORS_PANIC)
1016 seq_puts(m, ",errors=panic");
1017 else
1018 seq_puts(m, ",errors=remount-ro");
1019 if (opts->nfs == FAT_NFS_NOSTALE_RO)
1020 seq_puts(m, ",nfs=nostale_ro");
1021 else if (opts->nfs)
1022 seq_puts(m, ",nfs=stale_rw");
1023 if (opts->discard)
1024 seq_puts(m, ",discard");
1025 if (opts->dos1xfloppy)
1026 seq_puts(m, ",dos1xfloppy");
1027
1028 return 0;
1029 }
1030
1031 enum {
1032 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
1033 Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
1034 Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
1035 Opt_immutable, Opt_dots, Opt_nodots,
1036 Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
1037 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
1038 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
1039 Opt_obsolete, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
1040 Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_time_offset,
1041 Opt_nfs_stale_rw, Opt_nfs_nostale_ro, Opt_err, Opt_dos1xfloppy,
1042 };
1043
1044 static const match_table_t fat_tokens = {
1045 {Opt_check_r, "check=relaxed"},
1046 {Opt_check_s, "check=strict"},
1047 {Opt_check_n, "check=normal"},
1048 {Opt_check_r, "check=r"},
1049 {Opt_check_s, "check=s"},
1050 {Opt_check_n, "check=n"},
1051 {Opt_uid, "uid=%u"},
1052 {Opt_gid, "gid=%u"},
1053 {Opt_umask, "umask=%o"},
1054 {Opt_dmask, "dmask=%o"},
1055 {Opt_fmask, "fmask=%o"},
1056 {Opt_allow_utime, "allow_utime=%o"},
1057 {Opt_codepage, "codepage=%u"},
1058 {Opt_usefree, "usefree"},
1059 {Opt_nocase, "nocase"},
1060 {Opt_quiet, "quiet"},
1061 {Opt_showexec, "showexec"},
1062 {Opt_debug, "debug"},
1063 {Opt_immutable, "sys_immutable"},
1064 {Opt_flush, "flush"},
1065 {Opt_tz_utc, "tz=UTC"},
1066 {Opt_time_offset, "time_offset=%d"},
1067 {Opt_err_cont, "errors=continue"},
1068 {Opt_err_panic, "errors=panic"},
1069 {Opt_err_ro, "errors=remount-ro"},
1070 {Opt_discard, "discard"},
1071 {Opt_nfs_stale_rw, "nfs"},
1072 {Opt_nfs_stale_rw, "nfs=stale_rw"},
1073 {Opt_nfs_nostale_ro, "nfs=nostale_ro"},
1074 {Opt_dos1xfloppy, "dos1xfloppy"},
1075 {Opt_obsolete, "conv=binary"},
1076 {Opt_obsolete, "conv=text"},
1077 {Opt_obsolete, "conv=auto"},
1078 {Opt_obsolete, "conv=b"},
1079 {Opt_obsolete, "conv=t"},
1080 {Opt_obsolete, "conv=a"},
1081 {Opt_obsolete, "fat=%u"},
1082 {Opt_obsolete, "blocksize=%u"},
1083 {Opt_obsolete, "cvf_format=%20s"},
1084 {Opt_obsolete, "cvf_options=%100s"},
1085 {Opt_obsolete, "posix"},
1086 {Opt_err, NULL},
1087 };
1088 static const match_table_t msdos_tokens = {
1089 {Opt_nodots, "nodots"},
1090 {Opt_nodots, "dotsOK=no"},
1091 {Opt_dots, "dots"},
1092 {Opt_dots, "dotsOK=yes"},
1093 {Opt_err, NULL}
1094 };
1095 static const match_table_t vfat_tokens = {
1096 {Opt_charset, "iocharset=%s"},
1097 {Opt_shortname_lower, "shortname=lower"},
1098 {Opt_shortname_win95, "shortname=win95"},
1099 {Opt_shortname_winnt, "shortname=winnt"},
1100 {Opt_shortname_mixed, "shortname=mixed"},
1101 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */
1102 {Opt_utf8_no, "utf8=no"},
1103 {Opt_utf8_no, "utf8=false"},
1104 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */
1105 {Opt_utf8_yes, "utf8=yes"},
1106 {Opt_utf8_yes, "utf8=true"},
1107 {Opt_utf8_yes, "utf8"},
1108 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */
1109 {Opt_uni_xl_no, "uni_xlate=no"},
1110 {Opt_uni_xl_no, "uni_xlate=false"},
1111 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */
1112 {Opt_uni_xl_yes, "uni_xlate=yes"},
1113 {Opt_uni_xl_yes, "uni_xlate=true"},
1114 {Opt_uni_xl_yes, "uni_xlate"},
1115 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */
1116 {Opt_nonumtail_no, "nonumtail=no"},
1117 {Opt_nonumtail_no, "nonumtail=false"},
1118 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */
1119 {Opt_nonumtail_yes, "nonumtail=yes"},
1120 {Opt_nonumtail_yes, "nonumtail=true"},
1121 {Opt_nonumtail_yes, "nonumtail"},
1122 {Opt_rodir, "rodir"},
1123 {Opt_err, NULL}
1124 };
1125
parse_options(struct super_block * sb,char * options,int is_vfat,int silent,int * debug,struct fat_mount_options * opts)1126 static int parse_options(struct super_block *sb, char *options, int is_vfat,
1127 int silent, int *debug, struct fat_mount_options *opts)
1128 {
1129 char *p;
1130 substring_t args[MAX_OPT_ARGS];
1131 int option;
1132 char *iocharset;
1133
1134 opts->isvfat = is_vfat;
1135
1136 opts->fs_uid = current_uid();
1137 opts->fs_gid = current_gid();
1138 opts->fs_fmask = opts->fs_dmask = current_umask();
1139 opts->allow_utime = -1;
1140 opts->codepage = fat_default_codepage;
1141 fat_reset_iocharset(opts);
1142 if (is_vfat) {
1143 opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95;
1144 opts->rodir = 0;
1145 } else {
1146 opts->shortname = 0;
1147 opts->rodir = 1;
1148 }
1149 opts->name_check = 'n';
1150 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0;
1151 opts->unicode_xlate = 0;
1152 opts->numtail = 1;
1153 opts->usefree = opts->nocase = 0;
1154 opts->tz_set = 0;
1155 opts->nfs = 0;
1156 opts->errors = FAT_ERRORS_RO;
1157 *debug = 0;
1158
1159 opts->utf8 = IS_ENABLED(CONFIG_FAT_DEFAULT_UTF8) && is_vfat;
1160
1161 if (!options)
1162 goto out;
1163
1164 while ((p = strsep(&options, ",")) != NULL) {
1165 int token;
1166 if (!*p)
1167 continue;
1168
1169 token = match_token(p, fat_tokens, args);
1170 if (token == Opt_err) {
1171 if (is_vfat)
1172 token = match_token(p, vfat_tokens, args);
1173 else
1174 token = match_token(p, msdos_tokens, args);
1175 }
1176 switch (token) {
1177 case Opt_check_s:
1178 opts->name_check = 's';
1179 break;
1180 case Opt_check_r:
1181 opts->name_check = 'r';
1182 break;
1183 case Opt_check_n:
1184 opts->name_check = 'n';
1185 break;
1186 case Opt_usefree:
1187 opts->usefree = 1;
1188 break;
1189 case Opt_nocase:
1190 if (!is_vfat)
1191 opts->nocase = 1;
1192 else {
1193 /* for backward compatibility */
1194 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1195 | VFAT_SFN_CREATE_WIN95;
1196 }
1197 break;
1198 case Opt_quiet:
1199 opts->quiet = 1;
1200 break;
1201 case Opt_showexec:
1202 opts->showexec = 1;
1203 break;
1204 case Opt_debug:
1205 *debug = 1;
1206 break;
1207 case Opt_immutable:
1208 opts->sys_immutable = 1;
1209 break;
1210 case Opt_uid:
1211 if (match_int(&args[0], &option))
1212 return -EINVAL;
1213 opts->fs_uid = make_kuid(current_user_ns(), option);
1214 if (!uid_valid(opts->fs_uid))
1215 return -EINVAL;
1216 break;
1217 case Opt_gid:
1218 if (match_int(&args[0], &option))
1219 return -EINVAL;
1220 opts->fs_gid = make_kgid(current_user_ns(), option);
1221 if (!gid_valid(opts->fs_gid))
1222 return -EINVAL;
1223 break;
1224 case Opt_umask:
1225 if (match_octal(&args[0], &option))
1226 return -EINVAL;
1227 opts->fs_fmask = opts->fs_dmask = option;
1228 break;
1229 case Opt_dmask:
1230 if (match_octal(&args[0], &option))
1231 return -EINVAL;
1232 opts->fs_dmask = option;
1233 break;
1234 case Opt_fmask:
1235 if (match_octal(&args[0], &option))
1236 return -EINVAL;
1237 opts->fs_fmask = option;
1238 break;
1239 case Opt_allow_utime:
1240 if (match_octal(&args[0], &option))
1241 return -EINVAL;
1242 opts->allow_utime = option & (S_IWGRP | S_IWOTH);
1243 break;
1244 case Opt_codepage:
1245 if (match_int(&args[0], &option))
1246 return -EINVAL;
1247 opts->codepage = option;
1248 break;
1249 case Opt_flush:
1250 opts->flush = 1;
1251 break;
1252 case Opt_time_offset:
1253 if (match_int(&args[0], &option))
1254 return -EINVAL;
1255 /*
1256 * GMT+-12 zones may have DST corrections so at least
1257 * 13 hours difference is needed. Make the limit 24
1258 * just in case someone invents something unusual.
1259 */
1260 if (option < -24 * 60 || option > 24 * 60)
1261 return -EINVAL;
1262 opts->tz_set = 1;
1263 opts->time_offset = option;
1264 break;
1265 case Opt_tz_utc:
1266 opts->tz_set = 1;
1267 opts->time_offset = 0;
1268 break;
1269 case Opt_err_cont:
1270 opts->errors = FAT_ERRORS_CONT;
1271 break;
1272 case Opt_err_panic:
1273 opts->errors = FAT_ERRORS_PANIC;
1274 break;
1275 case Opt_err_ro:
1276 opts->errors = FAT_ERRORS_RO;
1277 break;
1278 case Opt_nfs_stale_rw:
1279 opts->nfs = FAT_NFS_STALE_RW;
1280 break;
1281 case Opt_nfs_nostale_ro:
1282 opts->nfs = FAT_NFS_NOSTALE_RO;
1283 break;
1284 case Opt_dos1xfloppy:
1285 opts->dos1xfloppy = 1;
1286 break;
1287
1288 /* msdos specific */
1289 case Opt_dots:
1290 opts->dotsOK = 1;
1291 break;
1292 case Opt_nodots:
1293 opts->dotsOK = 0;
1294 break;
1295
1296 /* vfat specific */
1297 case Opt_charset:
1298 fat_reset_iocharset(opts);
1299 iocharset = match_strdup(&args[0]);
1300 if (!iocharset)
1301 return -ENOMEM;
1302 opts->iocharset = iocharset;
1303 break;
1304 case Opt_shortname_lower:
1305 opts->shortname = VFAT_SFN_DISPLAY_LOWER
1306 | VFAT_SFN_CREATE_WIN95;
1307 break;
1308 case Opt_shortname_win95:
1309 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1310 | VFAT_SFN_CREATE_WIN95;
1311 break;
1312 case Opt_shortname_winnt:
1313 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1314 | VFAT_SFN_CREATE_WINNT;
1315 break;
1316 case Opt_shortname_mixed:
1317 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1318 | VFAT_SFN_CREATE_WIN95;
1319 break;
1320 case Opt_utf8_no: /* 0 or no or false */
1321 opts->utf8 = 0;
1322 break;
1323 case Opt_utf8_yes: /* empty or 1 or yes or true */
1324 opts->utf8 = 1;
1325 break;
1326 case Opt_uni_xl_no: /* 0 or no or false */
1327 opts->unicode_xlate = 0;
1328 break;
1329 case Opt_uni_xl_yes: /* empty or 1 or yes or true */
1330 opts->unicode_xlate = 1;
1331 break;
1332 case Opt_nonumtail_no: /* 0 or no or false */
1333 opts->numtail = 1; /* negated option */
1334 break;
1335 case Opt_nonumtail_yes: /* empty or 1 or yes or true */
1336 opts->numtail = 0; /* negated option */
1337 break;
1338 case Opt_rodir:
1339 opts->rodir = 1;
1340 break;
1341 case Opt_discard:
1342 opts->discard = 1;
1343 break;
1344
1345 /* obsolete mount options */
1346 case Opt_obsolete:
1347 fat_msg(sb, KERN_INFO, "\"%s\" option is obsolete, "
1348 "not supported now", p);
1349 break;
1350 /* unknown option */
1351 default:
1352 if (!silent) {
1353 fat_msg(sb, KERN_ERR,
1354 "Unrecognized mount option \"%s\" "
1355 "or missing value", p);
1356 }
1357 return -EINVAL;
1358 }
1359 }
1360
1361 out:
1362 /* UTF-8 doesn't provide FAT semantics */
1363 if (!strcmp(opts->iocharset, "utf8")) {
1364 fat_msg(sb, KERN_WARNING, "utf8 is not a recommended IO charset"
1365 " for FAT filesystems, filesystem will be "
1366 "case sensitive!");
1367 }
1368
1369 /* If user doesn't specify allow_utime, it's initialized from dmask. */
1370 if (opts->allow_utime == (unsigned short)-1)
1371 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1372 if (opts->unicode_xlate)
1373 opts->utf8 = 0;
1374 if (opts->nfs == FAT_NFS_NOSTALE_RO) {
1375 sb->s_flags |= SB_RDONLY;
1376 sb->s_export_op = &fat_export_ops_nostale;
1377 }
1378
1379 return 0;
1380 }
1381
fat_read_root(struct inode * inode)1382 static int fat_read_root(struct inode *inode)
1383 {
1384 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
1385 int error;
1386
1387 MSDOS_I(inode)->i_pos = MSDOS_ROOT_INO;
1388 inode->i_uid = sbi->options.fs_uid;
1389 inode->i_gid = sbi->options.fs_gid;
1390 inode_inc_iversion(inode);
1391 inode->i_generation = 0;
1392 inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
1393 inode->i_op = sbi->dir_ops;
1394 inode->i_fop = &fat_dir_operations;
1395 if (is_fat32(sbi)) {
1396 MSDOS_I(inode)->i_start = sbi->root_cluster;
1397 error = fat_calc_dir_size(inode);
1398 if (error < 0)
1399 return error;
1400 } else {
1401 MSDOS_I(inode)->i_start = 0;
1402 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1403 }
1404 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1405 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1406 MSDOS_I(inode)->i_logstart = 0;
1407 MSDOS_I(inode)->mmu_private = inode->i_size;
1408
1409 fat_save_attrs(inode, ATTR_DIR);
1410 inode->i_mtime = inode->i_atime = inode_set_ctime(inode, 0, 0);
1411 set_nlink(inode, fat_subdirs(inode)+2);
1412
1413 return 0;
1414 }
1415
calc_fat_clusters(struct super_block * sb)1416 static unsigned long calc_fat_clusters(struct super_block *sb)
1417 {
1418 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1419
1420 /* Divide first to avoid overflow */
1421 if (!is_fat12(sbi)) {
1422 unsigned long ent_per_sec = sb->s_blocksize * 8 / sbi->fat_bits;
1423 return ent_per_sec * sbi->fat_length;
1424 }
1425
1426 return sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1427 }
1428
fat_bpb_is_zero(struct fat_boot_sector * b)1429 static bool fat_bpb_is_zero(struct fat_boot_sector *b)
1430 {
1431 if (get_unaligned_le16(&b->sector_size))
1432 return false;
1433 if (b->sec_per_clus)
1434 return false;
1435 if (b->reserved)
1436 return false;
1437 if (b->fats)
1438 return false;
1439 if (get_unaligned_le16(&b->dir_entries))
1440 return false;
1441 if (get_unaligned_le16(&b->sectors))
1442 return false;
1443 if (b->media)
1444 return false;
1445 if (b->fat_length)
1446 return false;
1447 if (b->secs_track)
1448 return false;
1449 if (b->heads)
1450 return false;
1451 return true;
1452 }
1453
fat_read_bpb(struct super_block * sb,struct fat_boot_sector * b,int silent,struct fat_bios_param_block * bpb)1454 static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b,
1455 int silent, struct fat_bios_param_block *bpb)
1456 {
1457 int error = -EINVAL;
1458
1459 /* Read in BPB ... */
1460 memset(bpb, 0, sizeof(*bpb));
1461 bpb->fat_sector_size = get_unaligned_le16(&b->sector_size);
1462 bpb->fat_sec_per_clus = b->sec_per_clus;
1463 bpb->fat_reserved = le16_to_cpu(b->reserved);
1464 bpb->fat_fats = b->fats;
1465 bpb->fat_dir_entries = get_unaligned_le16(&b->dir_entries);
1466 bpb->fat_sectors = get_unaligned_le16(&b->sectors);
1467 bpb->fat_fat_length = le16_to_cpu(b->fat_length);
1468 bpb->fat_total_sect = le32_to_cpu(b->total_sect);
1469
1470 bpb->fat16_state = b->fat16.state;
1471 bpb->fat16_vol_id = get_unaligned_le32(b->fat16.vol_id);
1472
1473 bpb->fat32_length = le32_to_cpu(b->fat32.length);
1474 bpb->fat32_root_cluster = le32_to_cpu(b->fat32.root_cluster);
1475 bpb->fat32_info_sector = le16_to_cpu(b->fat32.info_sector);
1476 bpb->fat32_state = b->fat32.state;
1477 bpb->fat32_vol_id = get_unaligned_le32(b->fat32.vol_id);
1478
1479 /* Validate this looks like a FAT filesystem BPB */
1480 if (!bpb->fat_reserved) {
1481 if (!silent)
1482 fat_msg(sb, KERN_ERR,
1483 "bogus number of reserved sectors");
1484 goto out;
1485 }
1486 if (!bpb->fat_fats) {
1487 if (!silent)
1488 fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
1489 goto out;
1490 }
1491
1492 /*
1493 * Earlier we checked here that b->secs_track and b->head are nonzero,
1494 * but it turns out valid FAT filesystems can have zero there.
1495 */
1496
1497 if (!fat_valid_media(b->media)) {
1498 if (!silent)
1499 fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
1500 (unsigned)b->media);
1501 goto out;
1502 }
1503
1504 if (!is_power_of_2(bpb->fat_sector_size)
1505 || (bpb->fat_sector_size < 512)
1506 || (bpb->fat_sector_size > 4096)) {
1507 if (!silent)
1508 fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
1509 (unsigned)bpb->fat_sector_size);
1510 goto out;
1511 }
1512
1513 if (!is_power_of_2(bpb->fat_sec_per_clus)) {
1514 if (!silent)
1515 fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
1516 (unsigned)bpb->fat_sec_per_clus);
1517 goto out;
1518 }
1519
1520 if (bpb->fat_fat_length == 0 && bpb->fat32_length == 0) {
1521 if (!silent)
1522 fat_msg(sb, KERN_ERR, "bogus number of FAT sectors");
1523 goto out;
1524 }
1525
1526 error = 0;
1527
1528 out:
1529 return error;
1530 }
1531
fat_read_static_bpb(struct super_block * sb,struct fat_boot_sector * b,int silent,struct fat_bios_param_block * bpb)1532 static int fat_read_static_bpb(struct super_block *sb,
1533 struct fat_boot_sector *b, int silent,
1534 struct fat_bios_param_block *bpb)
1535 {
1536 static const char *notdos1x = "This doesn't look like a DOS 1.x volume";
1537 sector_t bd_sects = bdev_nr_sectors(sb->s_bdev);
1538 struct fat_floppy_defaults *fdefaults = NULL;
1539 int error = -EINVAL;
1540 unsigned i;
1541
1542 /* 16-bit DOS 1.x reliably wrote bootstrap short-jmp code */
1543 if (b->ignored[0] != 0xeb || b->ignored[2] != 0x90) {
1544 if (!silent)
1545 fat_msg(sb, KERN_ERR,
1546 "%s; no bootstrapping code", notdos1x);
1547 goto out;
1548 }
1549
1550 /*
1551 * If any value in this region is non-zero, it isn't archaic
1552 * DOS.
1553 */
1554 if (!fat_bpb_is_zero(b)) {
1555 if (!silent)
1556 fat_msg(sb, KERN_ERR,
1557 "%s; DOS 2.x BPB is non-zero", notdos1x);
1558 goto out;
1559 }
1560
1561 for (i = 0; i < ARRAY_SIZE(floppy_defaults); i++) {
1562 if (floppy_defaults[i].nr_sectors == bd_sects) {
1563 fdefaults = &floppy_defaults[i];
1564 break;
1565 }
1566 }
1567
1568 if (fdefaults == NULL) {
1569 if (!silent)
1570 fat_msg(sb, KERN_WARNING,
1571 "This looks like a DOS 1.x volume, but isn't a recognized floppy size (%llu sectors)",
1572 (u64)bd_sects);
1573 goto out;
1574 }
1575
1576 if (!silent)
1577 fat_msg(sb, KERN_INFO,
1578 "This looks like a DOS 1.x volume; assuming default BPB values");
1579
1580 memset(bpb, 0, sizeof(*bpb));
1581 bpb->fat_sector_size = SECTOR_SIZE;
1582 bpb->fat_sec_per_clus = fdefaults->sec_per_clus;
1583 bpb->fat_reserved = 1;
1584 bpb->fat_fats = 2;
1585 bpb->fat_dir_entries = fdefaults->dir_entries;
1586 bpb->fat_sectors = fdefaults->nr_sectors;
1587 bpb->fat_fat_length = fdefaults->fat_length;
1588
1589 error = 0;
1590
1591 out:
1592 return error;
1593 }
1594
1595 /*
1596 * Read the super block of an MS-DOS FS.
1597 */
fat_fill_super(struct super_block * sb,void * data,int silent,int isvfat,void (* setup)(struct super_block *))1598 int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
1599 void (*setup)(struct super_block *))
1600 {
1601 struct inode *root_inode = NULL, *fat_inode = NULL;
1602 struct inode *fsinfo_inode = NULL;
1603 struct buffer_head *bh;
1604 struct fat_bios_param_block bpb;
1605 struct msdos_sb_info *sbi;
1606 u16 logical_sector_size;
1607 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1608 int debug;
1609 long error;
1610 char buf[50];
1611 struct timespec64 ts;
1612
1613 /*
1614 * GFP_KERNEL is ok here, because while we do hold the
1615 * superblock lock, memory pressure can't call back into
1616 * the filesystem, since we're only just about to mount
1617 * it and have no inodes etc active!
1618 */
1619 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1620 if (!sbi)
1621 return -ENOMEM;
1622 sb->s_fs_info = sbi;
1623
1624 sb->s_flags |= SB_NODIRATIME;
1625 sb->s_magic = MSDOS_SUPER_MAGIC;
1626 sb->s_op = &fat_sops;
1627 sb->s_export_op = &fat_export_ops;
1628 /*
1629 * fat timestamps are complex and truncated by fat itself, so
1630 * we set 1 here to be fast
1631 */
1632 sb->s_time_gran = 1;
1633 mutex_init(&sbi->nfs_build_inode_lock);
1634 ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
1635 DEFAULT_RATELIMIT_BURST);
1636
1637 error = parse_options(sb, data, isvfat, silent, &debug, &sbi->options);
1638 if (error)
1639 goto out_fail;
1640
1641 setup(sb); /* flavour-specific stuff that needs options */
1642
1643 error = -EIO;
1644 sb_min_blocksize(sb, 512);
1645 bh = sb_bread(sb, 0);
1646 if (bh == NULL) {
1647 fat_msg(sb, KERN_ERR, "unable to read boot sector");
1648 goto out_fail;
1649 }
1650
1651 error = fat_read_bpb(sb, (struct fat_boot_sector *)bh->b_data, silent,
1652 &bpb);
1653 if (error == -EINVAL && sbi->options.dos1xfloppy)
1654 error = fat_read_static_bpb(sb,
1655 (struct fat_boot_sector *)bh->b_data, silent, &bpb);
1656 brelse(bh);
1657
1658 if (error == -EINVAL)
1659 goto out_invalid;
1660 else if (error)
1661 goto out_fail;
1662
1663 logical_sector_size = bpb.fat_sector_size;
1664 sbi->sec_per_clus = bpb.fat_sec_per_clus;
1665
1666 error = -EIO;
1667 if (logical_sector_size < sb->s_blocksize) {
1668 fat_msg(sb, KERN_ERR, "logical sector size too small for device"
1669 " (logical sector size = %u)", logical_sector_size);
1670 goto out_fail;
1671 }
1672
1673 if (logical_sector_size > sb->s_blocksize) {
1674 struct buffer_head *bh_resize;
1675
1676 if (!sb_set_blocksize(sb, logical_sector_size)) {
1677 fat_msg(sb, KERN_ERR, "unable to set blocksize %u",
1678 logical_sector_size);
1679 goto out_fail;
1680 }
1681
1682 /* Verify that the larger boot sector is fully readable */
1683 bh_resize = sb_bread(sb, 0);
1684 if (bh_resize == NULL) {
1685 fat_msg(sb, KERN_ERR, "unable to read boot sector"
1686 " (logical sector size = %lu)",
1687 sb->s_blocksize);
1688 goto out_fail;
1689 }
1690 brelse(bh_resize);
1691 }
1692
1693 mutex_init(&sbi->s_lock);
1694 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1695 sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1696 sbi->fats = bpb.fat_fats;
1697 sbi->fat_bits = 0; /* Don't know yet */
1698 sbi->fat_start = bpb.fat_reserved;
1699 sbi->fat_length = bpb.fat_fat_length;
1700 sbi->root_cluster = 0;
1701 sbi->free_clusters = -1; /* Don't know yet */
1702 sbi->free_clus_valid = 0;
1703 sbi->prev_free = FAT_START_ENT;
1704 sb->s_maxbytes = 0xffffffff;
1705 fat_time_fat2unix(sbi, &ts, 0, cpu_to_le16(FAT_DATE_MIN), 0);
1706 sb->s_time_min = ts.tv_sec;
1707
1708 fat_time_fat2unix(sbi, &ts, cpu_to_le16(FAT_TIME_MAX),
1709 cpu_to_le16(FAT_DATE_MAX), 0);
1710 sb->s_time_max = ts.tv_sec;
1711
1712 if (!sbi->fat_length && bpb.fat32_length) {
1713 struct fat_boot_fsinfo *fsinfo;
1714 struct buffer_head *fsinfo_bh;
1715
1716 /* Must be FAT32 */
1717 sbi->fat_bits = 32;
1718 sbi->fat_length = bpb.fat32_length;
1719 sbi->root_cluster = bpb.fat32_root_cluster;
1720
1721 /* MC - if info_sector is 0, don't multiply by 0 */
1722 sbi->fsinfo_sector = bpb.fat32_info_sector;
1723 if (sbi->fsinfo_sector == 0)
1724 sbi->fsinfo_sector = 1;
1725
1726 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1727 if (fsinfo_bh == NULL) {
1728 fat_msg(sb, KERN_ERR, "bread failed, FSINFO block"
1729 " (sector = %lu)", sbi->fsinfo_sector);
1730 goto out_fail;
1731 }
1732
1733 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1734 if (!IS_FSINFO(fsinfo)) {
1735 fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: "
1736 "0x%08x, 0x%08x (sector = %lu)",
1737 le32_to_cpu(fsinfo->signature1),
1738 le32_to_cpu(fsinfo->signature2),
1739 sbi->fsinfo_sector);
1740 } else {
1741 if (sbi->options.usefree)
1742 sbi->free_clus_valid = 1;
1743 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1744 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1745 }
1746
1747 brelse(fsinfo_bh);
1748 }
1749
1750 /* interpret volume ID as a little endian 32 bit integer */
1751 if (is_fat32(sbi))
1752 sbi->vol_id = bpb.fat32_vol_id;
1753 else /* fat 16 or 12 */
1754 sbi->vol_id = bpb.fat16_vol_id;
1755
1756 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1757 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1758
1759 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1760 sbi->dir_entries = bpb.fat_dir_entries;
1761 if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1762 if (!silent)
1763 fat_msg(sb, KERN_ERR, "bogus number of directory entries"
1764 " (%u)", sbi->dir_entries);
1765 goto out_invalid;
1766 }
1767
1768 rootdir_sectors = sbi->dir_entries
1769 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1770 sbi->data_start = sbi->dir_start + rootdir_sectors;
1771 total_sectors = bpb.fat_sectors;
1772 if (total_sectors == 0)
1773 total_sectors = bpb.fat_total_sect;
1774
1775 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1776
1777 if (!is_fat32(sbi))
1778 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1779
1780 /* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
1781 if (is_fat32(sbi))
1782 sbi->dirty = bpb.fat32_state & FAT_STATE_DIRTY;
1783 else /* fat 16 or 12 */
1784 sbi->dirty = bpb.fat16_state & FAT_STATE_DIRTY;
1785
1786 /* check that FAT table does not overflow */
1787 fat_clusters = calc_fat_clusters(sb);
1788 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1789 if (total_clusters > max_fat(sb)) {
1790 if (!silent)
1791 fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
1792 total_clusters);
1793 goto out_invalid;
1794 }
1795
1796 sbi->max_cluster = total_clusters + FAT_START_ENT;
1797 /* check the free_clusters, it's not necessarily correct */
1798 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1799 sbi->free_clusters = -1;
1800 /* check the prev_free, it's not necessarily correct */
1801 sbi->prev_free %= sbi->max_cluster;
1802 if (sbi->prev_free < FAT_START_ENT)
1803 sbi->prev_free = FAT_START_ENT;
1804
1805 /* set up enough so that it can read an inode */
1806 fat_hash_init(sb);
1807 dir_hash_init(sb);
1808 fat_ent_access_init(sb);
1809
1810 /*
1811 * The low byte of the first FAT entry must have the same value as
1812 * the media field of the boot sector. But in real world, too many
1813 * devices are writing wrong values. So, removed that validity check.
1814 *
1815 * The removed check compared the first FAT entry to a value dependent
1816 * on the media field like this:
1817 * == (0x0F00 | media), for FAT12
1818 * == (0XFF00 | media), for FAT16
1819 * == (0x0FFFFF | media), for FAT32
1820 */
1821
1822 error = -EINVAL;
1823 sprintf(buf, "cp%d", sbi->options.codepage);
1824 sbi->nls_disk = load_nls(buf);
1825 if (!sbi->nls_disk) {
1826 fat_msg(sb, KERN_ERR, "codepage %s not found", buf);
1827 goto out_fail;
1828 }
1829
1830 /* FIXME: utf8 is using iocharset for upper/lower conversion */
1831 if (sbi->options.isvfat) {
1832 sbi->nls_io = load_nls(sbi->options.iocharset);
1833 if (!sbi->nls_io) {
1834 fat_msg(sb, KERN_ERR, "IO charset %s not found",
1835 sbi->options.iocharset);
1836 goto out_fail;
1837 }
1838 }
1839
1840 error = -ENOMEM;
1841 fat_inode = new_inode(sb);
1842 if (!fat_inode)
1843 goto out_fail;
1844 sbi->fat_inode = fat_inode;
1845
1846 fsinfo_inode = new_inode(sb);
1847 if (!fsinfo_inode)
1848 goto out_fail;
1849 fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
1850 sbi->fsinfo_inode = fsinfo_inode;
1851 insert_inode_hash(fsinfo_inode);
1852
1853 root_inode = new_inode(sb);
1854 if (!root_inode)
1855 goto out_fail;
1856 root_inode->i_ino = MSDOS_ROOT_INO;
1857 inode_set_iversion(root_inode, 1);
1858 error = fat_read_root(root_inode);
1859 if (error < 0) {
1860 iput(root_inode);
1861 goto out_fail;
1862 }
1863 error = -ENOMEM;
1864 insert_inode_hash(root_inode);
1865 fat_attach(root_inode, 0);
1866 sb->s_root = d_make_root(root_inode);
1867 if (!sb->s_root) {
1868 fat_msg(sb, KERN_ERR, "get root inode failed");
1869 goto out_fail;
1870 }
1871
1872 if (sbi->options.discard && !bdev_max_discard_sectors(sb->s_bdev))
1873 fat_msg(sb, KERN_WARNING,
1874 "mounting with \"discard\" option, but the device does not support discard");
1875
1876 fat_set_state(sb, 1, 0);
1877 return 0;
1878
1879 out_invalid:
1880 error = -EINVAL;
1881 if (!silent)
1882 fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem");
1883
1884 out_fail:
1885 iput(fsinfo_inode);
1886 iput(fat_inode);
1887 unload_nls(sbi->nls_io);
1888 unload_nls(sbi->nls_disk);
1889 fat_reset_iocharset(&sbi->options);
1890 sb->s_fs_info = NULL;
1891 kfree(sbi);
1892 return error;
1893 }
1894
1895 EXPORT_SYMBOL_GPL(fat_fill_super);
1896
1897 /*
1898 * helper function for fat_flush_inodes. This writes both the inode
1899 * and the file data blocks, waiting for in flight data blocks before
1900 * the start of the call. It does not wait for any io started
1901 * during the call
1902 */
writeback_inode(struct inode * inode)1903 static int writeback_inode(struct inode *inode)
1904 {
1905
1906 int ret;
1907
1908 /* if we used wait=1, sync_inode_metadata waits for the io for the
1909 * inode to finish. So wait=0 is sent down to sync_inode_metadata
1910 * and filemap_fdatawrite is used for the data blocks
1911 */
1912 ret = sync_inode_metadata(inode, 0);
1913 if (!ret)
1914 ret = filemap_fdatawrite(inode->i_mapping);
1915 return ret;
1916 }
1917
1918 /*
1919 * write data and metadata corresponding to i1 and i2. The io is
1920 * started but we do not wait for any of it to finish.
1921 *
1922 * filemap_flush is used for the block device, so if there is a dirty
1923 * page for a block already in flight, we will not wait and start the
1924 * io over again
1925 */
fat_flush_inodes(struct super_block * sb,struct inode * i1,struct inode * i2)1926 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1927 {
1928 int ret = 0;
1929 if (!MSDOS_SB(sb)->options.flush)
1930 return 0;
1931 if (i1)
1932 ret = writeback_inode(i1);
1933 if (!ret && i2)
1934 ret = writeback_inode(i2);
1935 if (!ret)
1936 ret = sync_blockdev_nowait(sb->s_bdev);
1937 return ret;
1938 }
1939 EXPORT_SYMBOL_GPL(fat_flush_inodes);
1940
init_fat_fs(void)1941 static int __init init_fat_fs(void)
1942 {
1943 int err;
1944
1945 err = fat_cache_init();
1946 if (err)
1947 return err;
1948
1949 err = fat_init_inodecache();
1950 if (err)
1951 goto failed;
1952
1953 return 0;
1954
1955 failed:
1956 fat_cache_destroy();
1957 return err;
1958 }
1959
exit_fat_fs(void)1960 static void __exit exit_fat_fs(void)
1961 {
1962 fat_cache_destroy();
1963 fat_destroy_inodecache();
1964 }
1965
1966 module_init(init_fat_fs)
1967 module_exit(exit_fat_fs)
1968
1969 MODULE_LICENSE("GPL");
1970 MODULE_IMPORT_NS(ANDROID_GKI_VFS_EXPORT_ONLY);
1971