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_writepage(struct page * page,struct writeback_control * wbc)197 static int fat_writepage(struct page *page, struct writeback_control *wbc)
198 {
199 return block_write_full_page(page, fat_get_block, wbc);
200 }
201
fat_writepages(struct address_space * mapping,struct writeback_control * wbc)202 static int fat_writepages(struct address_space *mapping,
203 struct writeback_control *wbc)
204 {
205 return mpage_writepages(mapping, wbc, fat_get_block);
206 }
207
fat_readpage(struct file * file,struct page * page)208 static int fat_readpage(struct file *file, struct page *page)
209 {
210 return mpage_readpage(page, fat_get_block);
211 }
212
fat_readahead(struct readahead_control * rac)213 static void fat_readahead(struct readahead_control *rac)
214 {
215 mpage_readahead(rac, fat_get_block);
216 }
217
fat_write_failed(struct address_space * mapping,loff_t to)218 static void fat_write_failed(struct address_space *mapping, loff_t to)
219 {
220 struct inode *inode = mapping->host;
221
222 if (to > inode->i_size) {
223 truncate_pagecache(inode, inode->i_size);
224 fat_truncate_blocks(inode, inode->i_size);
225 }
226 }
227
fat_write_begin(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned flags,struct page ** pagep,void ** fsdata)228 static int fat_write_begin(struct file *file, struct address_space *mapping,
229 loff_t pos, unsigned len, unsigned flags,
230 struct page **pagep, void **fsdata)
231 {
232 int err;
233
234 *pagep = NULL;
235 err = cont_write_begin(file, mapping, pos, len, flags,
236 pagep, fsdata, fat_get_block,
237 &MSDOS_I(mapping->host)->mmu_private);
238 if (err < 0)
239 fat_write_failed(mapping, pos + len);
240 return err;
241 }
242
fat_write_end(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct page * pagep,void * fsdata)243 static int fat_write_end(struct file *file, struct address_space *mapping,
244 loff_t pos, unsigned len, unsigned copied,
245 struct page *pagep, void *fsdata)
246 {
247 struct inode *inode = mapping->host;
248 int err;
249 err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
250 if (err < len)
251 fat_write_failed(mapping, pos + len);
252 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
253 fat_truncate_time(inode, NULL, S_CTIME|S_MTIME);
254 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
255 mark_inode_dirty(inode);
256 }
257 return err;
258 }
259
fat_direct_IO(struct kiocb * iocb,struct iov_iter * iter)260 static ssize_t fat_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
261 {
262 struct file *file = iocb->ki_filp;
263 struct address_space *mapping = file->f_mapping;
264 struct inode *inode = mapping->host;
265 size_t count = iov_iter_count(iter);
266 loff_t offset = iocb->ki_pos;
267 ssize_t ret;
268
269 if (iov_iter_rw(iter) == WRITE) {
270 /*
271 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
272 * so we need to update the ->mmu_private to block boundary.
273 *
274 * But we must fill the remaining area or hole by nul for
275 * updating ->mmu_private.
276 *
277 * Return 0, and fallback to normal buffered write.
278 */
279 loff_t size = offset + count;
280 if (MSDOS_I(inode)->mmu_private < size)
281 return 0;
282 }
283
284 /*
285 * FAT need to use the DIO_LOCKING for avoiding the race
286 * condition of fat_get_block() and ->truncate().
287 */
288 ret = blockdev_direct_IO(iocb, inode, iter, fat_get_block);
289 if (ret < 0 && iov_iter_rw(iter) == WRITE)
290 fat_write_failed(mapping, offset + count);
291
292 return ret;
293 }
294
fat_get_block_bmap(struct inode * inode,sector_t iblock,struct buffer_head * bh_result,int create)295 static int fat_get_block_bmap(struct inode *inode, sector_t iblock,
296 struct buffer_head *bh_result, int create)
297 {
298 struct super_block *sb = inode->i_sb;
299 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
300 int err;
301 sector_t bmap;
302 unsigned long mapped_blocks;
303
304 BUG_ON(create != 0);
305
306 err = fat_bmap(inode, iblock, &bmap, &mapped_blocks, create, true);
307 if (err)
308 return err;
309
310 if (bmap) {
311 map_bh(bh_result, sb, bmap);
312 max_blocks = min(mapped_blocks, max_blocks);
313 }
314
315 bh_result->b_size = max_blocks << sb->s_blocksize_bits;
316
317 return 0;
318 }
319
_fat_bmap(struct address_space * mapping,sector_t block)320 static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
321 {
322 sector_t blocknr;
323
324 /* fat_get_cluster() assumes the requested blocknr isn't truncated. */
325 down_read(&MSDOS_I(mapping->host)->truncate_lock);
326 blocknr = generic_block_bmap(mapping, block, fat_get_block_bmap);
327 up_read(&MSDOS_I(mapping->host)->truncate_lock);
328
329 return blocknr;
330 }
331
332 /*
333 * fat_block_truncate_page() zeroes out a mapping from file offset `from'
334 * up to the end of the block which corresponds to `from'.
335 * This is required during truncate to physically zeroout the tail end
336 * of that block so it doesn't yield old data if the file is later grown.
337 * Also, avoid causing failure from fsx for cases of "data past EOF"
338 */
fat_block_truncate_page(struct inode * inode,loff_t from)339 int fat_block_truncate_page(struct inode *inode, loff_t from)
340 {
341 return block_truncate_page(inode->i_mapping, from, fat_get_block);
342 }
343
344 static const struct address_space_operations fat_aops = {
345 .readpage = fat_readpage,
346 .readahead = fat_readahead,
347 .writepage = fat_writepage,
348 .writepages = fat_writepages,
349 .write_begin = fat_write_begin,
350 .write_end = fat_write_end,
351 .direct_IO = fat_direct_IO,
352 .bmap = _fat_bmap
353 };
354
355 /*
356 * New FAT inode stuff. We do the following:
357 * a) i_ino is constant and has nothing with on-disk location.
358 * b) FAT manages its own cache of directory entries.
359 * c) *This* cache is indexed by on-disk location.
360 * d) inode has an associated directory entry, all right, but
361 * it may be unhashed.
362 * e) currently entries are stored within struct inode. That should
363 * change.
364 * f) we deal with races in the following way:
365 * 1. readdir() and lookup() do FAT-dir-cache lookup.
366 * 2. rename() unhashes the F-d-c entry and rehashes it in
367 * a new place.
368 * 3. unlink() and rmdir() unhash F-d-c entry.
369 * 4. fat_write_inode() checks whether the thing is unhashed.
370 * If it is we silently return. If it isn't we do bread(),
371 * check if the location is still valid and retry if it
372 * isn't. Otherwise we do changes.
373 * 5. Spinlock is used to protect hash/unhash/location check/lookup
374 * 6. fat_evict_inode() unhashes the F-d-c entry.
375 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry
376 * and consider negative result as cache miss.
377 */
378
fat_hash_init(struct super_block * sb)379 static void fat_hash_init(struct super_block *sb)
380 {
381 struct msdos_sb_info *sbi = MSDOS_SB(sb);
382 int i;
383
384 spin_lock_init(&sbi->inode_hash_lock);
385 for (i = 0; i < FAT_HASH_SIZE; i++)
386 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
387 }
388
fat_hash(loff_t i_pos)389 static inline unsigned long fat_hash(loff_t i_pos)
390 {
391 return hash_32(i_pos, FAT_HASH_BITS);
392 }
393
dir_hash_init(struct super_block * sb)394 static void dir_hash_init(struct super_block *sb)
395 {
396 struct msdos_sb_info *sbi = MSDOS_SB(sb);
397 int i;
398
399 spin_lock_init(&sbi->dir_hash_lock);
400 for (i = 0; i < FAT_HASH_SIZE; i++)
401 INIT_HLIST_HEAD(&sbi->dir_hashtable[i]);
402 }
403
fat_attach(struct inode * inode,loff_t i_pos)404 void fat_attach(struct inode *inode, loff_t i_pos)
405 {
406 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
407
408 if (inode->i_ino != MSDOS_ROOT_INO) {
409 struct hlist_head *head = sbi->inode_hashtable
410 + fat_hash(i_pos);
411
412 spin_lock(&sbi->inode_hash_lock);
413 MSDOS_I(inode)->i_pos = i_pos;
414 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
415 spin_unlock(&sbi->inode_hash_lock);
416 }
417
418 /* If NFS support is enabled, cache the mapping of start cluster
419 * to directory inode. This is used during reconnection of
420 * dentries to the filesystem root.
421 */
422 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
423 struct hlist_head *d_head = sbi->dir_hashtable;
424 d_head += fat_dir_hash(MSDOS_I(inode)->i_logstart);
425
426 spin_lock(&sbi->dir_hash_lock);
427 hlist_add_head(&MSDOS_I(inode)->i_dir_hash, d_head);
428 spin_unlock(&sbi->dir_hash_lock);
429 }
430 }
431 EXPORT_SYMBOL_GPL(fat_attach);
432
fat_detach(struct inode * inode)433 void fat_detach(struct inode *inode)
434 {
435 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
436 spin_lock(&sbi->inode_hash_lock);
437 MSDOS_I(inode)->i_pos = 0;
438 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
439 spin_unlock(&sbi->inode_hash_lock);
440
441 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
442 spin_lock(&sbi->dir_hash_lock);
443 hlist_del_init(&MSDOS_I(inode)->i_dir_hash);
444 spin_unlock(&sbi->dir_hash_lock);
445 }
446 }
447 EXPORT_SYMBOL_GPL(fat_detach);
448
fat_iget(struct super_block * sb,loff_t i_pos)449 struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
450 {
451 struct msdos_sb_info *sbi = MSDOS_SB(sb);
452 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
453 struct msdos_inode_info *i;
454 struct inode *inode = NULL;
455
456 spin_lock(&sbi->inode_hash_lock);
457 hlist_for_each_entry(i, head, i_fat_hash) {
458 BUG_ON(i->vfs_inode.i_sb != sb);
459 if (i->i_pos != i_pos)
460 continue;
461 inode = igrab(&i->vfs_inode);
462 if (inode)
463 break;
464 }
465 spin_unlock(&sbi->inode_hash_lock);
466 return inode;
467 }
468
is_exec(unsigned char * extension)469 static int is_exec(unsigned char *extension)
470 {
471 unsigned char exe_extensions[] = "EXECOMBAT", *walk;
472
473 for (walk = exe_extensions; *walk; walk += 3)
474 if (!strncmp(extension, walk, 3))
475 return 1;
476 return 0;
477 }
478
fat_calc_dir_size(struct inode * inode)479 static int fat_calc_dir_size(struct inode *inode)
480 {
481 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
482 int ret, fclus, dclus;
483
484 inode->i_size = 0;
485 if (MSDOS_I(inode)->i_start == 0)
486 return 0;
487
488 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
489 if (ret < 0)
490 return ret;
491 inode->i_size = (fclus + 1) << sbi->cluster_bits;
492
493 return 0;
494 }
495
fat_validate_dir(struct inode * dir)496 static int fat_validate_dir(struct inode *dir)
497 {
498 struct super_block *sb = dir->i_sb;
499
500 if (dir->i_nlink < 2) {
501 /* Directory should have "."/".." entries at least. */
502 fat_fs_error(sb, "corrupted directory (invalid entries)");
503 return -EIO;
504 }
505 if (MSDOS_I(dir)->i_start == 0 ||
506 MSDOS_I(dir)->i_start == MSDOS_SB(sb)->root_cluster) {
507 /* Directory should point valid cluster. */
508 fat_fs_error(sb, "corrupted directory (invalid i_start)");
509 return -EIO;
510 }
511 return 0;
512 }
513
514 /* doesn't deal with root inode */
fat_fill_inode(struct inode * inode,struct msdos_dir_entry * de)515 int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
516 {
517 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
518 int error;
519
520 MSDOS_I(inode)->i_pos = 0;
521 inode->i_uid = sbi->options.fs_uid;
522 inode->i_gid = sbi->options.fs_gid;
523 inode_inc_iversion(inode);
524 inode->i_generation = prandom_u32();
525
526 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
527 inode->i_generation &= ~1;
528 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
529 inode->i_op = sbi->dir_ops;
530 inode->i_fop = &fat_dir_operations;
531
532 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
533 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
534 error = fat_calc_dir_size(inode);
535 if (error < 0)
536 return error;
537 MSDOS_I(inode)->mmu_private = inode->i_size;
538
539 set_nlink(inode, fat_subdirs(inode));
540
541 error = fat_validate_dir(inode);
542 if (error < 0)
543 return error;
544 } else { /* not a directory */
545 inode->i_generation |= 1;
546 inode->i_mode = fat_make_mode(sbi, de->attr,
547 ((sbi->options.showexec && !is_exec(de->name + 8))
548 ? S_IRUGO|S_IWUGO : S_IRWXUGO));
549 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
550
551 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
552 inode->i_size = le32_to_cpu(de->size);
553 inode->i_op = &fat_file_inode_operations;
554 inode->i_fop = &fat_file_operations;
555 inode->i_mapping->a_ops = &fat_aops;
556 MSDOS_I(inode)->mmu_private = inode->i_size;
557 }
558 if (de->attr & ATTR_SYS) {
559 if (sbi->options.sys_immutable)
560 inode->i_flags |= S_IMMUTABLE;
561 }
562 fat_save_attrs(inode, de->attr);
563
564 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
565 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
566
567 fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0);
568 if (sbi->options.isvfat) {
569 fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime,
570 de->cdate, de->ctime_cs);
571 fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
572 } else
573 fat_truncate_time(inode, &inode->i_mtime, S_ATIME|S_CTIME);
574
575 return 0;
576 }
577
fat_lock_build_inode(struct msdos_sb_info * sbi)578 static inline void fat_lock_build_inode(struct msdos_sb_info *sbi)
579 {
580 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
581 mutex_lock(&sbi->nfs_build_inode_lock);
582 }
583
fat_unlock_build_inode(struct msdos_sb_info * sbi)584 static inline void fat_unlock_build_inode(struct msdos_sb_info *sbi)
585 {
586 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
587 mutex_unlock(&sbi->nfs_build_inode_lock);
588 }
589
fat_build_inode(struct super_block * sb,struct msdos_dir_entry * de,loff_t i_pos)590 struct inode *fat_build_inode(struct super_block *sb,
591 struct msdos_dir_entry *de, loff_t i_pos)
592 {
593 struct inode *inode;
594 int err;
595
596 fat_lock_build_inode(MSDOS_SB(sb));
597 inode = fat_iget(sb, i_pos);
598 if (inode)
599 goto out;
600 inode = new_inode(sb);
601 if (!inode) {
602 inode = ERR_PTR(-ENOMEM);
603 goto out;
604 }
605 inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
606 inode_set_iversion(inode, 1);
607 err = fat_fill_inode(inode, de);
608 if (err) {
609 iput(inode);
610 inode = ERR_PTR(err);
611 goto out;
612 }
613 fat_attach(inode, i_pos);
614 insert_inode_hash(inode);
615 out:
616 fat_unlock_build_inode(MSDOS_SB(sb));
617 return inode;
618 }
619
620 EXPORT_SYMBOL_GPL(fat_build_inode);
621
622 static int __fat_write_inode(struct inode *inode, int wait);
623
fat_free_eofblocks(struct inode * inode)624 static void fat_free_eofblocks(struct inode *inode)
625 {
626 /* Release unwritten fallocated blocks on inode eviction. */
627 if ((inode->i_blocks << 9) >
628 round_up(MSDOS_I(inode)->mmu_private,
629 MSDOS_SB(inode->i_sb)->cluster_size)) {
630 int err;
631
632 fat_truncate_blocks(inode, MSDOS_I(inode)->mmu_private);
633 /* Fallocate results in updating the i_start/iogstart
634 * for the zero byte file. So, make it return to
635 * original state during evict and commit it to avoid
636 * any corruption on the next access to the cluster
637 * chain for the file.
638 */
639 err = __fat_write_inode(inode, inode_needs_sync(inode));
640 if (err) {
641 fat_msg(inode->i_sb, KERN_WARNING, "Failed to "
642 "update on disk inode for unused "
643 "fallocated blocks, inode could be "
644 "corrupted. Please run fsck");
645 }
646
647 }
648 }
649
fat_evict_inode(struct inode * inode)650 static void fat_evict_inode(struct inode *inode)
651 {
652 truncate_inode_pages_final(&inode->i_data);
653 if (!inode->i_nlink) {
654 inode->i_size = 0;
655 fat_truncate_blocks(inode, 0);
656 } else
657 fat_free_eofblocks(inode);
658
659 invalidate_inode_buffers(inode);
660 clear_inode(inode);
661 fat_cache_inval_inode(inode);
662 fat_detach(inode);
663 }
664
fat_set_state(struct super_block * sb,unsigned int set,unsigned int force)665 static void fat_set_state(struct super_block *sb,
666 unsigned int set, unsigned int force)
667 {
668 struct buffer_head *bh;
669 struct fat_boot_sector *b;
670 struct msdos_sb_info *sbi = MSDOS_SB(sb);
671
672 /* do not change any thing if mounted read only */
673 if (sb_rdonly(sb) && !force)
674 return;
675
676 /* do not change state if fs was dirty */
677 if (sbi->dirty) {
678 /* warn only on set (mount). */
679 if (set)
680 fat_msg(sb, KERN_WARNING, "Volume was not properly "
681 "unmounted. Some data may be corrupt. "
682 "Please run fsck.");
683 return;
684 }
685
686 bh = sb_bread(sb, 0);
687 if (bh == NULL) {
688 fat_msg(sb, KERN_ERR, "unable to read boot sector "
689 "to mark fs as dirty");
690 return;
691 }
692
693 b = (struct fat_boot_sector *) bh->b_data;
694
695 if (is_fat32(sbi)) {
696 if (set)
697 b->fat32.state |= FAT_STATE_DIRTY;
698 else
699 b->fat32.state &= ~FAT_STATE_DIRTY;
700 } else /* fat 16 and 12 */ {
701 if (set)
702 b->fat16.state |= FAT_STATE_DIRTY;
703 else
704 b->fat16.state &= ~FAT_STATE_DIRTY;
705 }
706
707 mark_buffer_dirty(bh);
708 sync_dirty_buffer(bh);
709 brelse(bh);
710 }
711
fat_reset_iocharset(struct fat_mount_options * opts)712 static void fat_reset_iocharset(struct fat_mount_options *opts)
713 {
714 if (opts->iocharset != fat_default_iocharset) {
715 /* Note: opts->iocharset can be NULL here */
716 kfree(opts->iocharset);
717 opts->iocharset = fat_default_iocharset;
718 }
719 }
720
delayed_free(struct rcu_head * p)721 static void delayed_free(struct rcu_head *p)
722 {
723 struct msdos_sb_info *sbi = container_of(p, struct msdos_sb_info, rcu);
724 unload_nls(sbi->nls_disk);
725 unload_nls(sbi->nls_io);
726 fat_reset_iocharset(&sbi->options);
727 kfree(sbi);
728 }
729
fat_put_super(struct super_block * sb)730 static void fat_put_super(struct super_block *sb)
731 {
732 struct msdos_sb_info *sbi = MSDOS_SB(sb);
733
734 fat_set_state(sb, 0, 0);
735
736 iput(sbi->fsinfo_inode);
737 iput(sbi->fat_inode);
738
739 call_rcu(&sbi->rcu, delayed_free);
740 }
741
742 static struct kmem_cache *fat_inode_cachep;
743
fat_alloc_inode(struct super_block * sb)744 static struct inode *fat_alloc_inode(struct super_block *sb)
745 {
746 struct msdos_inode_info *ei;
747 ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
748 if (!ei)
749 return NULL;
750
751 init_rwsem(&ei->truncate_lock);
752 /* Zeroing to allow iput() even if partial initialized inode. */
753 ei->mmu_private = 0;
754 ei->i_start = 0;
755 ei->i_logstart = 0;
756 ei->i_attrs = 0;
757 ei->i_pos = 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_ctime, &raw_entry->ctime,
890 &raw_entry->cdate, &raw_entry->ctime_cs);
891 fat_time_unix2fat(sbi, &inode->i_atime, &atime,
892 &raw_entry->adate, NULL);
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.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1411 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1412 set_nlink(inode, fat_subdirs(inode)+2);
1413
1414 return 0;
1415 }
1416
calc_fat_clusters(struct super_block * sb)1417 static unsigned long calc_fat_clusters(struct super_block *sb)
1418 {
1419 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1420
1421 /* Divide first to avoid overflow */
1422 if (!is_fat12(sbi)) {
1423 unsigned long ent_per_sec = sb->s_blocksize * 8 / sbi->fat_bits;
1424 return ent_per_sec * sbi->fat_length;
1425 }
1426
1427 return sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1428 }
1429
fat_bpb_is_zero(struct fat_boot_sector * b)1430 static bool fat_bpb_is_zero(struct fat_boot_sector *b)
1431 {
1432 if (get_unaligned_le16(&b->sector_size))
1433 return false;
1434 if (b->sec_per_clus)
1435 return false;
1436 if (b->reserved)
1437 return false;
1438 if (b->fats)
1439 return false;
1440 if (get_unaligned_le16(&b->dir_entries))
1441 return false;
1442 if (get_unaligned_le16(&b->sectors))
1443 return false;
1444 if (b->media)
1445 return false;
1446 if (b->fat_length)
1447 return false;
1448 if (b->secs_track)
1449 return false;
1450 if (b->heads)
1451 return false;
1452 return true;
1453 }
1454
fat_read_bpb(struct super_block * sb,struct fat_boot_sector * b,int silent,struct fat_bios_param_block * bpb)1455 static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b,
1456 int silent, struct fat_bios_param_block *bpb)
1457 {
1458 int error = -EINVAL;
1459
1460 /* Read in BPB ... */
1461 memset(bpb, 0, sizeof(*bpb));
1462 bpb->fat_sector_size = get_unaligned_le16(&b->sector_size);
1463 bpb->fat_sec_per_clus = b->sec_per_clus;
1464 bpb->fat_reserved = le16_to_cpu(b->reserved);
1465 bpb->fat_fats = b->fats;
1466 bpb->fat_dir_entries = get_unaligned_le16(&b->dir_entries);
1467 bpb->fat_sectors = get_unaligned_le16(&b->sectors);
1468 bpb->fat_fat_length = le16_to_cpu(b->fat_length);
1469 bpb->fat_total_sect = le32_to_cpu(b->total_sect);
1470
1471 bpb->fat16_state = b->fat16.state;
1472 bpb->fat16_vol_id = get_unaligned_le32(b->fat16.vol_id);
1473
1474 bpb->fat32_length = le32_to_cpu(b->fat32.length);
1475 bpb->fat32_root_cluster = le32_to_cpu(b->fat32.root_cluster);
1476 bpb->fat32_info_sector = le16_to_cpu(b->fat32.info_sector);
1477 bpb->fat32_state = b->fat32.state;
1478 bpb->fat32_vol_id = get_unaligned_le32(b->fat32.vol_id);
1479
1480 /* Validate this looks like a FAT filesystem BPB */
1481 if (!bpb->fat_reserved) {
1482 if (!silent)
1483 fat_msg(sb, KERN_ERR,
1484 "bogus number of reserved sectors");
1485 goto out;
1486 }
1487 if (!bpb->fat_fats) {
1488 if (!silent)
1489 fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
1490 goto out;
1491 }
1492
1493 /*
1494 * Earlier we checked here that b->secs_track and b->head are nonzero,
1495 * but it turns out valid FAT filesystems can have zero there.
1496 */
1497
1498 if (!fat_valid_media(b->media)) {
1499 if (!silent)
1500 fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
1501 (unsigned)b->media);
1502 goto out;
1503 }
1504
1505 if (!is_power_of_2(bpb->fat_sector_size)
1506 || (bpb->fat_sector_size < 512)
1507 || (bpb->fat_sector_size > 4096)) {
1508 if (!silent)
1509 fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
1510 (unsigned)bpb->fat_sector_size);
1511 goto out;
1512 }
1513
1514 if (!is_power_of_2(bpb->fat_sec_per_clus)) {
1515 if (!silent)
1516 fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
1517 (unsigned)bpb->fat_sec_per_clus);
1518 goto out;
1519 }
1520
1521 if (bpb->fat_fat_length == 0 && bpb->fat32_length == 0) {
1522 if (!silent)
1523 fat_msg(sb, KERN_ERR, "bogus number of FAT sectors");
1524 goto out;
1525 }
1526
1527 error = 0;
1528
1529 out:
1530 return error;
1531 }
1532
fat_read_static_bpb(struct super_block * sb,struct fat_boot_sector * b,int silent,struct fat_bios_param_block * bpb)1533 static int fat_read_static_bpb(struct super_block *sb,
1534 struct fat_boot_sector *b, int silent,
1535 struct fat_bios_param_block *bpb)
1536 {
1537 static const char *notdos1x = "This doesn't look like a DOS 1.x volume";
1538
1539 struct fat_floppy_defaults *fdefaults = NULL;
1540 int error = -EINVAL;
1541 sector_t bd_sects;
1542 unsigned i;
1543
1544 bd_sects = i_size_read(sb->s_bdev->bd_inode) / SECTOR_SIZE;
1545
1546 /* 16-bit DOS 1.x reliably wrote bootstrap short-jmp code */
1547 if (b->ignored[0] != 0xeb || b->ignored[2] != 0x90) {
1548 if (!silent)
1549 fat_msg(sb, KERN_ERR,
1550 "%s; no bootstrapping code", notdos1x);
1551 goto out;
1552 }
1553
1554 /*
1555 * If any value in this region is non-zero, it isn't archaic
1556 * DOS.
1557 */
1558 if (!fat_bpb_is_zero(b)) {
1559 if (!silent)
1560 fat_msg(sb, KERN_ERR,
1561 "%s; DOS 2.x BPB is non-zero", notdos1x);
1562 goto out;
1563 }
1564
1565 for (i = 0; i < ARRAY_SIZE(floppy_defaults); i++) {
1566 if (floppy_defaults[i].nr_sectors == bd_sects) {
1567 fdefaults = &floppy_defaults[i];
1568 break;
1569 }
1570 }
1571
1572 if (fdefaults == NULL) {
1573 if (!silent)
1574 fat_msg(sb, KERN_WARNING,
1575 "This looks like a DOS 1.x volume, but isn't a recognized floppy size (%llu sectors)",
1576 (u64)bd_sects);
1577 goto out;
1578 }
1579
1580 if (!silent)
1581 fat_msg(sb, KERN_INFO,
1582 "This looks like a DOS 1.x volume; assuming default BPB values");
1583
1584 memset(bpb, 0, sizeof(*bpb));
1585 bpb->fat_sector_size = SECTOR_SIZE;
1586 bpb->fat_sec_per_clus = fdefaults->sec_per_clus;
1587 bpb->fat_reserved = 1;
1588 bpb->fat_fats = 2;
1589 bpb->fat_dir_entries = fdefaults->dir_entries;
1590 bpb->fat_sectors = fdefaults->nr_sectors;
1591 bpb->fat_fat_length = fdefaults->fat_length;
1592
1593 error = 0;
1594
1595 out:
1596 return error;
1597 }
1598
1599 /*
1600 * Read the super block of an MS-DOS FS.
1601 */
fat_fill_super(struct super_block * sb,void * data,int silent,int isvfat,void (* setup)(struct super_block *))1602 int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
1603 void (*setup)(struct super_block *))
1604 {
1605 struct inode *root_inode = NULL, *fat_inode = NULL;
1606 struct inode *fsinfo_inode = NULL;
1607 struct buffer_head *bh;
1608 struct fat_bios_param_block bpb;
1609 struct msdos_sb_info *sbi;
1610 u16 logical_sector_size;
1611 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1612 int debug;
1613 long error;
1614 char buf[50];
1615 struct timespec64 ts;
1616
1617 /*
1618 * GFP_KERNEL is ok here, because while we do hold the
1619 * superblock lock, memory pressure can't call back into
1620 * the filesystem, since we're only just about to mount
1621 * it and have no inodes etc active!
1622 */
1623 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1624 if (!sbi)
1625 return -ENOMEM;
1626 sb->s_fs_info = sbi;
1627
1628 sb->s_flags |= SB_NODIRATIME;
1629 sb->s_magic = MSDOS_SUPER_MAGIC;
1630 sb->s_op = &fat_sops;
1631 sb->s_export_op = &fat_export_ops;
1632 /*
1633 * fat timestamps are complex and truncated by fat itself, so
1634 * we set 1 here to be fast
1635 */
1636 sb->s_time_gran = 1;
1637 mutex_init(&sbi->nfs_build_inode_lock);
1638 ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
1639 DEFAULT_RATELIMIT_BURST);
1640
1641 error = parse_options(sb, data, isvfat, silent, &debug, &sbi->options);
1642 if (error)
1643 goto out_fail;
1644
1645 setup(sb); /* flavour-specific stuff that needs options */
1646
1647 error = -EIO;
1648 sb_min_blocksize(sb, 512);
1649 bh = sb_bread(sb, 0);
1650 if (bh == NULL) {
1651 fat_msg(sb, KERN_ERR, "unable to read boot sector");
1652 goto out_fail;
1653 }
1654
1655 error = fat_read_bpb(sb, (struct fat_boot_sector *)bh->b_data, silent,
1656 &bpb);
1657 if (error == -EINVAL && sbi->options.dos1xfloppy)
1658 error = fat_read_static_bpb(sb,
1659 (struct fat_boot_sector *)bh->b_data, silent, &bpb);
1660 brelse(bh);
1661
1662 if (error == -EINVAL)
1663 goto out_invalid;
1664 else if (error)
1665 goto out_fail;
1666
1667 logical_sector_size = bpb.fat_sector_size;
1668 sbi->sec_per_clus = bpb.fat_sec_per_clus;
1669
1670 error = -EIO;
1671 if (logical_sector_size < sb->s_blocksize) {
1672 fat_msg(sb, KERN_ERR, "logical sector size too small for device"
1673 " (logical sector size = %u)", logical_sector_size);
1674 goto out_fail;
1675 }
1676
1677 if (logical_sector_size > sb->s_blocksize) {
1678 struct buffer_head *bh_resize;
1679
1680 if (!sb_set_blocksize(sb, logical_sector_size)) {
1681 fat_msg(sb, KERN_ERR, "unable to set blocksize %u",
1682 logical_sector_size);
1683 goto out_fail;
1684 }
1685
1686 /* Verify that the larger boot sector is fully readable */
1687 bh_resize = sb_bread(sb, 0);
1688 if (bh_resize == NULL) {
1689 fat_msg(sb, KERN_ERR, "unable to read boot sector"
1690 " (logical sector size = %lu)",
1691 sb->s_blocksize);
1692 goto out_fail;
1693 }
1694 brelse(bh_resize);
1695 }
1696
1697 mutex_init(&sbi->s_lock);
1698 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1699 sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1700 sbi->fats = bpb.fat_fats;
1701 sbi->fat_bits = 0; /* Don't know yet */
1702 sbi->fat_start = bpb.fat_reserved;
1703 sbi->fat_length = bpb.fat_fat_length;
1704 sbi->root_cluster = 0;
1705 sbi->free_clusters = -1; /* Don't know yet */
1706 sbi->free_clus_valid = 0;
1707 sbi->prev_free = FAT_START_ENT;
1708 sb->s_maxbytes = 0xffffffff;
1709 fat_time_fat2unix(sbi, &ts, 0, cpu_to_le16(FAT_DATE_MIN), 0);
1710 sb->s_time_min = ts.tv_sec;
1711
1712 fat_time_fat2unix(sbi, &ts, cpu_to_le16(FAT_TIME_MAX),
1713 cpu_to_le16(FAT_DATE_MAX), 0);
1714 sb->s_time_max = ts.tv_sec;
1715
1716 if (!sbi->fat_length && bpb.fat32_length) {
1717 struct fat_boot_fsinfo *fsinfo;
1718 struct buffer_head *fsinfo_bh;
1719
1720 /* Must be FAT32 */
1721 sbi->fat_bits = 32;
1722 sbi->fat_length = bpb.fat32_length;
1723 sbi->root_cluster = bpb.fat32_root_cluster;
1724
1725 /* MC - if info_sector is 0, don't multiply by 0 */
1726 sbi->fsinfo_sector = bpb.fat32_info_sector;
1727 if (sbi->fsinfo_sector == 0)
1728 sbi->fsinfo_sector = 1;
1729
1730 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1731 if (fsinfo_bh == NULL) {
1732 fat_msg(sb, KERN_ERR, "bread failed, FSINFO block"
1733 " (sector = %lu)", sbi->fsinfo_sector);
1734 goto out_fail;
1735 }
1736
1737 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1738 if (!IS_FSINFO(fsinfo)) {
1739 fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: "
1740 "0x%08x, 0x%08x (sector = %lu)",
1741 le32_to_cpu(fsinfo->signature1),
1742 le32_to_cpu(fsinfo->signature2),
1743 sbi->fsinfo_sector);
1744 } else {
1745 if (sbi->options.usefree)
1746 sbi->free_clus_valid = 1;
1747 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1748 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1749 }
1750
1751 brelse(fsinfo_bh);
1752 }
1753
1754 /* interpret volume ID as a little endian 32 bit integer */
1755 if (is_fat32(sbi))
1756 sbi->vol_id = bpb.fat32_vol_id;
1757 else /* fat 16 or 12 */
1758 sbi->vol_id = bpb.fat16_vol_id;
1759
1760 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1761 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1762
1763 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1764 sbi->dir_entries = bpb.fat_dir_entries;
1765 if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1766 if (!silent)
1767 fat_msg(sb, KERN_ERR, "bogus number of directory entries"
1768 " (%u)", sbi->dir_entries);
1769 goto out_invalid;
1770 }
1771
1772 rootdir_sectors = sbi->dir_entries
1773 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1774 sbi->data_start = sbi->dir_start + rootdir_sectors;
1775 total_sectors = bpb.fat_sectors;
1776 if (total_sectors == 0)
1777 total_sectors = bpb.fat_total_sect;
1778
1779 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1780
1781 if (!is_fat32(sbi))
1782 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1783
1784 /* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
1785 if (is_fat32(sbi))
1786 sbi->dirty = bpb.fat32_state & FAT_STATE_DIRTY;
1787 else /* fat 16 or 12 */
1788 sbi->dirty = bpb.fat16_state & FAT_STATE_DIRTY;
1789
1790 /* check that FAT table does not overflow */
1791 fat_clusters = calc_fat_clusters(sb);
1792 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1793 if (total_clusters > max_fat(sb)) {
1794 if (!silent)
1795 fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
1796 total_clusters);
1797 goto out_invalid;
1798 }
1799
1800 sbi->max_cluster = total_clusters + FAT_START_ENT;
1801 /* check the free_clusters, it's not necessarily correct */
1802 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1803 sbi->free_clusters = -1;
1804 /* check the prev_free, it's not necessarily correct */
1805 sbi->prev_free %= sbi->max_cluster;
1806 if (sbi->prev_free < FAT_START_ENT)
1807 sbi->prev_free = FAT_START_ENT;
1808
1809 /* set up enough so that it can read an inode */
1810 fat_hash_init(sb);
1811 dir_hash_init(sb);
1812 fat_ent_access_init(sb);
1813
1814 /*
1815 * The low byte of the first FAT entry must have the same value as
1816 * the media field of the boot sector. But in real world, too many
1817 * devices are writing wrong values. So, removed that validity check.
1818 *
1819 * The removed check compared the first FAT entry to a value dependent
1820 * on the media field like this:
1821 * == (0x0F00 | media), for FAT12
1822 * == (0XFF00 | media), for FAT16
1823 * == (0x0FFFFF | media), for FAT32
1824 */
1825
1826 error = -EINVAL;
1827 sprintf(buf, "cp%d", sbi->options.codepage);
1828 sbi->nls_disk = load_nls(buf);
1829 if (!sbi->nls_disk) {
1830 fat_msg(sb, KERN_ERR, "codepage %s not found", buf);
1831 goto out_fail;
1832 }
1833
1834 /* FIXME: utf8 is using iocharset for upper/lower conversion */
1835 if (sbi->options.isvfat) {
1836 sbi->nls_io = load_nls(sbi->options.iocharset);
1837 if (!sbi->nls_io) {
1838 fat_msg(sb, KERN_ERR, "IO charset %s not found",
1839 sbi->options.iocharset);
1840 goto out_fail;
1841 }
1842 }
1843
1844 error = -ENOMEM;
1845 fat_inode = new_inode(sb);
1846 if (!fat_inode)
1847 goto out_fail;
1848 sbi->fat_inode = fat_inode;
1849
1850 fsinfo_inode = new_inode(sb);
1851 if (!fsinfo_inode)
1852 goto out_fail;
1853 fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
1854 sbi->fsinfo_inode = fsinfo_inode;
1855 insert_inode_hash(fsinfo_inode);
1856
1857 root_inode = new_inode(sb);
1858 if (!root_inode)
1859 goto out_fail;
1860 root_inode->i_ino = MSDOS_ROOT_INO;
1861 inode_set_iversion(root_inode, 1);
1862 error = fat_read_root(root_inode);
1863 if (error < 0) {
1864 iput(root_inode);
1865 goto out_fail;
1866 }
1867 error = -ENOMEM;
1868 insert_inode_hash(root_inode);
1869 fat_attach(root_inode, 0);
1870 sb->s_root = d_make_root(root_inode);
1871 if (!sb->s_root) {
1872 fat_msg(sb, KERN_ERR, "get root inode failed");
1873 goto out_fail;
1874 }
1875
1876 if (sbi->options.discard) {
1877 struct request_queue *q = bdev_get_queue(sb->s_bdev);
1878 if (!blk_queue_discard(q))
1879 fat_msg(sb, KERN_WARNING,
1880 "mounting with \"discard\" option, but "
1881 "the device does not support discard");
1882 }
1883
1884 fat_set_state(sb, 1, 0);
1885 return 0;
1886
1887 out_invalid:
1888 error = -EINVAL;
1889 if (!silent)
1890 fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem");
1891
1892 out_fail:
1893 if (fsinfo_inode)
1894 iput(fsinfo_inode);
1895 if (fat_inode)
1896 iput(fat_inode);
1897 unload_nls(sbi->nls_io);
1898 unload_nls(sbi->nls_disk);
1899 fat_reset_iocharset(&sbi->options);
1900 sb->s_fs_info = NULL;
1901 kfree(sbi);
1902 return error;
1903 }
1904
1905 EXPORT_SYMBOL_GPL(fat_fill_super);
1906
1907 /*
1908 * helper function for fat_flush_inodes. This writes both the inode
1909 * and the file data blocks, waiting for in flight data blocks before
1910 * the start of the call. It does not wait for any io started
1911 * during the call
1912 */
writeback_inode(struct inode * inode)1913 static int writeback_inode(struct inode *inode)
1914 {
1915
1916 int ret;
1917
1918 /* if we used wait=1, sync_inode_metadata waits for the io for the
1919 * inode to finish. So wait=0 is sent down to sync_inode_metadata
1920 * and filemap_fdatawrite is used for the data blocks
1921 */
1922 ret = sync_inode_metadata(inode, 0);
1923 if (!ret)
1924 ret = filemap_fdatawrite(inode->i_mapping);
1925 return ret;
1926 }
1927
1928 /*
1929 * write data and metadata corresponding to i1 and i2. The io is
1930 * started but we do not wait for any of it to finish.
1931 *
1932 * filemap_flush is used for the block device, so if there is a dirty
1933 * page for a block already in flight, we will not wait and start the
1934 * io over again
1935 */
fat_flush_inodes(struct super_block * sb,struct inode * i1,struct inode * i2)1936 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1937 {
1938 int ret = 0;
1939 if (!MSDOS_SB(sb)->options.flush)
1940 return 0;
1941 if (i1)
1942 ret = writeback_inode(i1);
1943 if (!ret && i2)
1944 ret = writeback_inode(i2);
1945 if (!ret) {
1946 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
1947 ret = filemap_flush(mapping);
1948 }
1949 return ret;
1950 }
1951 EXPORT_SYMBOL_GPL(fat_flush_inodes);
1952
init_fat_fs(void)1953 static int __init init_fat_fs(void)
1954 {
1955 int err;
1956
1957 err = fat_cache_init();
1958 if (err)
1959 return err;
1960
1961 err = fat_init_inodecache();
1962 if (err)
1963 goto failed;
1964
1965 return 0;
1966
1967 failed:
1968 fat_cache_destroy();
1969 return err;
1970 }
1971
exit_fat_fs(void)1972 static void __exit exit_fat_fs(void)
1973 {
1974 fat_cache_destroy();
1975 fat_destroy_inodecache();
1976 }
1977
1978 module_init(init_fat_fs)
1979 module_exit(exit_fat_fs)
1980
1981 MODULE_LICENSE("GPL");
1982