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[linux-2.6-block.git] / fs / fat / inode.c
CommitLineData
1da177e4
LT		 1/*
2 * linux/fs/fat/inode.c
3 *
4 * Written 1992,1993 by Werner Almesberger
5 * VFAT extensions by Gordon Chaffee, merged with msdos fs by Henrik Storner
6 * Rewritten for the constant inumbers support by Al Viro
7 *
8 * Fixes:
9 *
10 * Max Cohan: Fixed invalid FSINFO offset when info_sector is 0
11 */
12
13#include <linux/module.h>
1da177e4 14#include <linux/pagemap.h>
a5425d29 15#include <linux/mpage.h>
1da177e4 16#include <linux/vfs.h>
58932ef7 17#include <linux/seq_file.h>
1da177e4 18#include <linux/parser.h>
e5174baa 19#include <linux/uio.h>
f562146a 20#include <linux/blkdev.h>
66114cad 21#include <linux/backing-dev.h>
1da177e4 22#include <asm/unaligned.h>
2489dbab 23#include <linux/iversion.h>
9e975dae 24#include "fat.h"
1da177e4
LT		 25
26#ifndef CONFIG_FAT_DEFAULT_IOCHARSET
27/* if user don't select VFAT, this is undefined. */
28#define CONFIG_FAT_DEFAULT_IOCHARSET ""
29#endif
30
190a8843
CM		 31#define KB_IN_SECTORS 2
32
33/*
34 * A deserialized copy of the on-disk structure laid out in struct
35 * fat_boot_sector.
36 */
37struct fat_bios_param_block {
38 u16 fat_sector_size;
39 u8 fat_sec_per_clus;
40 u16 fat_reserved;
41 u8 fat_fats;
42 u16 fat_dir_entries;
43 u16 fat_sectors;
44 u16 fat_fat_length;
45 u32 fat_total_sect;
46
47 u8 fat16_state;
48 u32 fat16_vol_id;
49
50 u32 fat32_length;
51 u32 fat32_root_cluster;
52 u16 fat32_info_sector;
53 u8 fat32_state;
54 u32 fat32_vol_id;
55};
56
1da177e4
LT		 57static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
58static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
59
190a8843
CM		 60static struct fat_floppy_defaults {
61 unsigned nr_sectors;
62 unsigned sec_per_clus;
63 unsigned dir_entries;
64 unsigned media;
65 unsigned fat_length;
66} floppy_defaults[] = {
67{
68 .nr_sectors = 160 * KB_IN_SECTORS,
69 .sec_per_clus = 1,
70 .dir_entries = 64,
71 .media = 0xFE,
72 .fat_length = 1,
73},
74{
75 .nr_sectors = 180 * KB_IN_SECTORS,
76 .sec_per_clus = 1,
77 .dir_entries = 64,
78 .media = 0xFC,
79 .fat_length = 2,
80},
81{
82 .nr_sectors = 320 * KB_IN_SECTORS,
83 .sec_per_clus = 2,
84 .dir_entries = 112,
85 .media = 0xFF,
86 .fat_length = 1,
87},
88{
89 .nr_sectors = 360 * KB_IN_SECTORS,
90 .sec_per_clus = 2,
91 .dir_entries = 112,
92 .media = 0xFD,
93 .fat_length = 2,
94},
95};
1da177e4 96
b13bb33e 97int fat_add_cluster(struct inode *inode)
1da177e4
LT		 98{
99 int err, cluster;
100
101 err = fat_alloc_clusters(inode, &cluster, 1);
102 if (err)
103 return err;
104 /* FIXME: this cluster should be added after data of this
105 * cluster is writed */
106 err = fat_chain_add(inode, cluster, 1);
107 if (err)
108 fat_free_clusters(inode, cluster);
109 return err;
110}
111
6a1d9805
OH		 112static inline int __fat_get_block(struct inode *inode, sector_t iblock,
113 unsigned long *max_blocks,
114 struct buffer_head *bh_result, int create)
1da177e4
LT		 115{
116 struct super_block *sb = inode->i_sb;
e5174baa 117 struct msdos_sb_info *sbi = MSDOS_SB(sb);
e5174baa 118 unsigned long mapped_blocks;
7e0f236b 119 sector_t phys, last_block;
e5174baa 120 int err, offset;
1da177e4 121
16fab201 122 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create, false);
1da177e4
LT		 123 if (err)
124 return err;
125 if (phys) {
126 map_bh(bh_result, sb, phys);
e5174baa 127 *max_blocks = min(mapped_blocks, *max_blocks);
1da177e4
LT		 128 return 0;
129 }
130 if (!create)
131 return 0;
e5174baa 132
1da177e4 133 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
85c78591 134 fat_fs_error(sb, "corrupted file size (i_pos %lld, %lld)",
6a1d9805 135 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
1da177e4
LT		 136 return -EIO;
137 }
e5174baa 138
7e0f236b 139 last_block = inode->i_blocks >> (sb->s_blocksize_bits - 9);
e5174baa 140 offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
7e0f236b
NJ		 141 /*
142 * allocate a cluster according to the following.
143 * 1) no more available blocks
144 * 2) not part of fallocate region
145 */
146 if (!offset && !(iblock < last_block)) {
e5174baa 147 /* TODO: multiple cluster allocation would be desirable. */
1da177e4
LT		 148 err = fat_add_cluster(inode);
149 if (err)
150 return err;
151 }
e5174baa
OH		 152 /* available blocks on this cluster */
153 mapped_blocks = sbi->sec_per_clus - offset;
154
155 *max_blocks = min(mapped_blocks, *max_blocks);
156 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
157
16fab201 158 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create, false);
1da177e4
LT		 159 if (err)
160 return err;
c2574aaa
OH		 161 if (!phys) {
162 fat_fs_error(sb,
163 "invalid FAT chain (i_pos %lld, last_block %llu)",
164 MSDOS_I(inode)->i_pos,
165 (unsigned long long)last_block);
166 return -EIO;
167 }
6a1d9805 168
e5174baa 169 BUG_ON(*max_blocks != mapped_blocks);
1da177e4
LT		 170 set_buffer_new(bh_result);
171 map_bh(bh_result, sb, phys);
6a1d9805 172
1da177e4
LT		 173 return 0;
174}
175
6a1d9805
OH		 176static int fat_get_block(struct inode *inode, sector_t iblock,
177 struct buffer_head *bh_result, int create)
e5174baa
OH		 178{
179 struct super_block *sb = inode->i_sb;
1d8fa7a2 180 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
6a1d9805 181 int err;
e5174baa 182
6a1d9805 183 err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create);
e5174baa
OH		 184 if (err)
185 return err;
186 bh_result->b_size = max_blocks << sb->s_blocksize_bits;
187 return 0;
188}
189
1da177e4
LT		 190static int fat_writepage(struct page *page, struct writeback_control *wbc)
191{
192 return block_write_full_page(page, fat_get_block, wbc);
193}
194
a5425d29
OH		 195static int fat_writepages(struct address_space *mapping,
196 struct writeback_control *wbc)
197{
198 return mpage_writepages(mapping, wbc, fat_get_block);
199}
200
1da177e4
LT		 201static int fat_readpage(struct file *file, struct page *page)
202{
a5425d29
OH		 203 return mpage_readpage(page, fat_get_block);
204}
205
206static int fat_readpages(struct file *file, struct address_space *mapping,
207 struct list_head *pages, unsigned nr_pages)
208{
209 return mpage_readpages(mapping, pages, nr_pages, fat_get_block);
1da177e4
LT		 210}
211
459f6ed3 212static void fat_write_failed(struct address_space *mapping, loff_t to)
213{
214 struct inode *inode = mapping->host;
215
216 if (to > inode->i_size) {
7caef267 217 truncate_pagecache(inode, inode->i_size);
459f6ed3 218 fat_truncate_blocks(inode, inode->i_size);
219 }
220}
221
d7777a25
NP		 222static int fat_write_begin(struct file *file, struct address_space *mapping,
223 loff_t pos, unsigned len, unsigned flags,
224 struct page **pagep, void **fsdata)
1da177e4 225{
459f6ed3 226 int err;
227
d7777a25 228 *pagep = NULL;
282dc178 229 err = cont_write_begin(file, mapping, pos, len, flags,
459f6ed3 230 pagep, fsdata, fat_get_block,
d7777a25 231 &MSDOS_I(mapping->host)->mmu_private);
459f6ed3 232 if (err < 0)
233 fat_write_failed(mapping, pos + len);
234 return err;
1da177e4
LT		 235}
236
d7777a25
NP		 237static int fat_write_end(struct file *file, struct address_space *mapping,
238 loff_t pos, unsigned len, unsigned copied,
239 struct page *pagep, void *fsdata)
ef402268 240{
d7777a25
NP		 241 struct inode *inode = mapping->host;
242 int err;
243 err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
459f6ed3 244 if (err < len)
245 fat_write_failed(mapping, pos + len);
d7777a25 246 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
cd83f6b1 247 fat_truncate_time(inode, NULL, S_CTIME|S_MTIME);
ef402268
OH		 248 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
249 mark_inode_dirty(inode);
250 }
251 return err;
252}
253
c8b8e32d 254static ssize_t fat_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
e5174baa
OH		 255{
256 struct file *file = iocb->ki_filp;
459f6ed3 257 struct address_space *mapping = file->f_mapping;
258 struct inode *inode = mapping->host;
a6cbcd4a 259 size_t count = iov_iter_count(iter);
c8b8e32d 260 loff_t offset = iocb->ki_pos;
459f6ed3 261 ssize_t ret;
e5174baa 262
6f673763 263 if (iov_iter_rw(iter) == WRITE) {
e5174baa 264 /*
4e02ed4b 265 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
e5174baa
OH		 266 * so we need to update the ->mmu_private to block boundary.
267 *
268 * But we must fill the remaining area or hole by nul for
269 * updating ->mmu_private.
94412a96
OH		 270 *
271 * Return 0, and fallback to normal buffered write.
e5174baa 272 */
a6cbcd4a 273 loff_t size = offset + count;
e5174baa 274 if (MSDOS_I(inode)->mmu_private < size)
94412a96 275 return 0;
e5174baa
OH		 276 }
277
278 /*
279 * FAT need to use the DIO_LOCKING for avoiding the race
280 * condition of fat_get_block() and ->truncate().
281 */
c8b8e32d 282 ret = blockdev_direct_IO(iocb, inode, iter, fat_get_block);
6f673763 283 if (ret < 0 && iov_iter_rw(iter) == WRITE)
a6cbcd4a 284 fat_write_failed(mapping, offset + count);
459f6ed3 285
286 return ret;
e5174baa
OH		 287}
288
16fab201
NJ		 289static int fat_get_block_bmap(struct inode *inode, sector_t iblock,
290 struct buffer_head *bh_result, int create)
291{
292 struct super_block *sb = inode->i_sb;
293 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
294 int err;
295 sector_t bmap;
296 unsigned long mapped_blocks;
297
298 BUG_ON(create != 0);
299
300 err = fat_bmap(inode, iblock, &bmap, &mapped_blocks, create, true);
301 if (err)
302 return err;
303
304 if (bmap) {
305 map_bh(bh_result, sb, bmap);
306 max_blocks = min(mapped_blocks, max_blocks);
307 }
308
309 bh_result->b_size = max_blocks << sb->s_blocksize_bits;
310
311 return 0;
312}
313
1da177e4
LT		 314static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
315{
fa93ca18
OH		 316 sector_t blocknr;
317
318 /* fat_get_cluster() assumes the requested blocknr isn't truncated. */
58268691 319 down_read(&MSDOS_I(mapping->host)->truncate_lock);
16fab201 320 blocknr = generic_block_bmap(mapping, block, fat_get_block_bmap);
58268691 321 up_read(&MSDOS_I(mapping->host)->truncate_lock);
fa93ca18
OH		 322
323 return blocknr;
1da177e4
LT		 324}
325
c0ef0cc9
NJ		 326/*
327 * fat_block_truncate_page() zeroes out a mapping from file offset `from'
328 * up to the end of the block which corresponds to `from'.
329 * This is required during truncate to physically zeroout the tail end
330 * of that block so it doesn't yield old data if the file is later grown.
331 * Also, avoid causing failure from fsx for cases of "data past EOF"
332 */
333int fat_block_truncate_page(struct inode *inode, loff_t from)
334{
335 return block_truncate_page(inode->i_mapping, from, fat_get_block);
336}
337
f5e54d6e 338static const struct address_space_operations fat_aops = {
1da177e4 339 .readpage = fat_readpage,
a5425d29 340 .readpages = fat_readpages,
1da177e4 341 .writepage = fat_writepage,
a5425d29 342 .writepages = fat_writepages,
d7777a25
NP		 343 .write_begin = fat_write_begin,
344 .write_end = fat_write_end,
e5174baa 345 .direct_IO = fat_direct_IO,
1da177e4
LT		 346 .bmap = _fat_bmap
347};
348
349/*
350 * New FAT inode stuff. We do the following:
351 * a) i_ino is constant and has nothing with on-disk location.
352 * b) FAT manages its own cache of directory entries.
353 * c) *This* cache is indexed by on-disk location.
354 * d) inode has an associated directory entry, all right, but
355 * it may be unhashed.
356 * e) currently entries are stored within struct inode. That should
357 * change.
358 * f) we deal with races in the following way:
359 * 1. readdir() and lookup() do FAT-dir-cache lookup.
360 * 2. rename() unhashes the F-d-c entry and rehashes it in
361 * a new place.
362 * 3. unlink() and rmdir() unhash F-d-c entry.
363 * 4. fat_write_inode() checks whether the thing is unhashed.
364 * If it is we silently return. If it isn't we do bread(),
365 * check if the location is still valid and retry if it
366 * isn't. Otherwise we do changes.
367 * 5. Spinlock is used to protect hash/unhash/location check/lookup
deee3ce4 368 * 6. fat_evict_inode() unhashes the F-d-c entry.
1da177e4
LT		 369 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry
370 * and consider negative result as cache miss.
371 */
372
373static void fat_hash_init(struct super_block *sb)
374{
375 struct msdos_sb_info *sbi = MSDOS_SB(sb);
376 int i;
377
378 spin_lock_init(&sbi->inode_hash_lock);
379 for (i = 0; i < FAT_HASH_SIZE; i++)
380 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
381}
382
d3dfa822 383static inline unsigned long fat_hash(loff_t i_pos)
1da177e4 384{
d3dfa822 385 return hash_32(i_pos, FAT_HASH_BITS);
1da177e4
LT		 386}
387
7669e8fb
SM		 388static void dir_hash_init(struct super_block *sb)
389{
390 struct msdos_sb_info *sbi = MSDOS_SB(sb);
391 int i;
392
393 spin_lock_init(&sbi->dir_hash_lock);
394 for (i = 0; i < FAT_HASH_SIZE; i++)
395 INIT_HLIST_HEAD(&sbi->dir_hashtable[i]);
396}
397
1da177e4
LT		 398void fat_attach(struct inode *inode, loff_t i_pos)
399{
d3dfa822 400 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
1da177e4 401
7669e8fb
SM		 402 if (inode->i_ino != MSDOS_ROOT_INO) {
403 struct hlist_head *head = sbi->inode_hashtable
404 + fat_hash(i_pos);
405
406 spin_lock(&sbi->inode_hash_lock);
407 MSDOS_I(inode)->i_pos = i_pos;
408 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
409 spin_unlock(&sbi->inode_hash_lock);
410 }
411
412 /* If NFS support is enabled, cache the mapping of start cluster
413 * to directory inode. This is used during reconnection of
414 * dentries to the filesystem root.
415 */
416 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
417 struct hlist_head *d_head = sbi->dir_hashtable;
418 d_head += fat_dir_hash(MSDOS_I(inode)->i_logstart);
419
420 spin_lock(&sbi->dir_hash_lock);
421 hlist_add_head(&MSDOS_I(inode)->i_dir_hash, d_head);
422 spin_unlock(&sbi->dir_hash_lock);
423 }
1da177e4 424}
7c709d00 425EXPORT_SYMBOL_GPL(fat_attach);
1da177e4
LT		 426
427void fat_detach(struct inode *inode)
428{
429 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
430 spin_lock(&sbi->inode_hash_lock);
431 MSDOS_I(inode)->i_pos = 0;
432 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
433 spin_unlock(&sbi->inode_hash_lock);
7669e8fb
SM		 434
435 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
436 spin_lock(&sbi->dir_hash_lock);
437 hlist_del_init(&MSDOS_I(inode)->i_dir_hash);
438 spin_unlock(&sbi->dir_hash_lock);
439 }
1da177e4 440}
7c709d00 441EXPORT_SYMBOL_GPL(fat_detach);
1da177e4
LT		 442
443struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
444{
445 struct msdos_sb_info *sbi = MSDOS_SB(sb);
d3dfa822 446 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
1da177e4
LT		 447 struct msdos_inode_info *i;
448 struct inode *inode = NULL;
449
450 spin_lock(&sbi->inode_hash_lock);
b67bfe0d 451 hlist_for_each_entry(i, head, i_fat_hash) {
1da177e4
LT		 452 BUG_ON(i->vfs_inode.i_sb != sb);
453 if (i->i_pos != i_pos)
454 continue;
455 inode = igrab(&i->vfs_inode);
456 if (inode)
457 break;
458 }
459 spin_unlock(&sbi->inode_hash_lock);
460 return inode;
461}
462
463static int is_exec(unsigned char *extension)
464{
ef19470e 465 unsigned char exe_extensions[] = "EXECOMBAT", *walk;
1da177e4
LT		 466
467 for (walk = exe_extensions; *walk; walk += 3)
468 if (!strncmp(extension, walk, 3))
469 return 1;
470 return 0;
471}
472
473static int fat_calc_dir_size(struct inode *inode)
474{
475 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
476 int ret, fclus, dclus;
477
478 inode->i_size = 0;
479 if (MSDOS_I(inode)->i_start == 0)
480 return 0;
481
482 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
483 if (ret < 0)
484 return ret;
485 inode->i_size = (fclus + 1) << sbi->cluster_bits;
486
487 return 0;
488}
489
a3082d52
OH		 490static int fat_validate_dir(struct inode *dir)
491{
492 struct super_block *sb = dir->i_sb;
493
494 if (dir->i_nlink < 2) {
495 /* Directory should have "."/".." entries at least. */
496 fat_fs_error(sb, "corrupted directory (invalid entries)");
497 return -EIO;
498 }
499 if (MSDOS_I(dir)->i_start == 0 ||
500 MSDOS_I(dir)->i_start == MSDOS_SB(sb)->root_cluster) {
501 /* Directory should point valid cluster. */
502 fat_fs_error(sb, "corrupted directory (invalid i_start)");
503 return -EIO;
504 }
505 return 0;
506}
507
1da177e4 508/* doesn't deal with root inode */
f1e6fb0a 509int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
1da177e4
LT		 510{
511 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
512 int error;
513
514 MSDOS_I(inode)->i_pos = 0;
515 inode->i_uid = sbi->options.fs_uid;
516 inode->i_gid = sbi->options.fs_gid;
2489dbab 517 inode_inc_iversion(inode);
1da177e4
LT		 518 inode->i_generation = get_seconds();
519
520 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
521 inode->i_generation &= ~1;
9c0aa1b8 522 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
1da177e4
LT		 523 inode->i_op = sbi->dir_ops;
524 inode->i_fop = &fat_dir_operations;
525
a943ed71 526 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
1da177e4
LT		 527 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
528 error = fat_calc_dir_size(inode);
529 if (error < 0)
530 return error;
531 MSDOS_I(inode)->mmu_private = inode->i_size;
532
bfe86848 533 set_nlink(inode, fat_subdirs(inode));
a3082d52
OH		 534
535 error = fat_validate_dir(inode);
536 if (error < 0)
537 return error;
1da177e4
LT		 538 } else { /* not a directory */
539 inode->i_generation |= 1;
9c0aa1b8
OH		 540 inode->i_mode = fat_make_mode(sbi, de->attr,
541 ((sbi->options.showexec && !is_exec(de->name + 8))
542 ? S_IRUGO|S_IWUGO : S_IRWXUGO));
a943ed71 543 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
1da177e4
LT		 544
545 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
546 inode->i_size = le32_to_cpu(de->size);
547 inode->i_op = &fat_file_inode_operations;
548 inode->i_fop = &fat_file_operations;
549 inode->i_mapping->a_ops = &fat_aops;
550 MSDOS_I(inode)->mmu_private = inode->i_size;
551 }
552 if (de->attr & ATTR_SYS) {
553 if (sbi->options.sys_immutable)
554 inode->i_flags |= S_IMMUTABLE;
555 }
9c0aa1b8
OH		 556 fat_save_attrs(inode, de->attr);
557
1da177e4
LT		 558 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
559 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
7decd1cb 560
f423420c 561 fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0);
1da177e4 562 if (sbi->options.isvfat) {
f423420c 563 fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime,
7decd1cb 564 de->cdate, de->ctime_cs);
f423420c 565 fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
1da177e4 566 } else
cd83f6b1 567 fat_truncate_time(inode, &inode->i_mtime, S_ATIME|S_CTIME);
1da177e4
LT		 568
569 return 0;
570}
571
8fceb4e0
NJ		 572static inline void fat_lock_build_inode(struct msdos_sb_info *sbi)
573{
574 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
575 mutex_lock(&sbi->nfs_build_inode_lock);
576}
577
578static inline void fat_unlock_build_inode(struct msdos_sb_info *sbi)
579{
580 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
581 mutex_unlock(&sbi->nfs_build_inode_lock);
582}
583
1da177e4
LT		 584struct inode *fat_build_inode(struct super_block *sb,
585 struct msdos_dir_entry *de, loff_t i_pos)
586{
587 struct inode *inode;
588 int err;
589
8fceb4e0 590 fat_lock_build_inode(MSDOS_SB(sb));
1da177e4
LT		 591 inode = fat_iget(sb, i_pos);
592 if (inode)
593 goto out;
594 inode = new_inode(sb);
595 if (!inode) {
596 inode = ERR_PTR(-ENOMEM);
597 goto out;
598 }
599 inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
2489dbab 600 inode_set_iversion(inode, 1);
1da177e4
LT		 601 err = fat_fill_inode(inode, de);
602 if (err) {
603 iput(inode);
604 inode = ERR_PTR(err);
605 goto out;
606 }
607 fat_attach(inode, i_pos);
608 insert_inode_hash(inode);
609out:
8fceb4e0 610 fat_unlock_build_inode(MSDOS_SB(sb));
1da177e4
LT		 611 return inode;
612}
613
7c709d00 614EXPORT_SYMBOL_GPL(fat_build_inode);
1da177e4 615
b13bb33e
NJ		 616static int __fat_write_inode(struct inode *inode, int wait);
617
618static void fat_free_eofblocks(struct inode *inode)
619{
620 /* Release unwritten fallocated blocks on inode eviction. */
621 if ((inode->i_blocks << 9) >
622 round_up(MSDOS_I(inode)->mmu_private,
623 MSDOS_SB(inode->i_sb)->cluster_size)) {
624 int err;
625
626 fat_truncate_blocks(inode, MSDOS_I(inode)->mmu_private);
627 /* Fallocate results in updating the i_start/iogstart
628 * for the zero byte file. So, make it return to
629 * original state during evict and commit it to avoid
630 * any corruption on the next access to the cluster
631 * chain for the file.
632 */
633 err = __fat_write_inode(inode, inode_needs_sync(inode));
634 if (err) {
635 fat_msg(inode->i_sb, KERN_WARNING, "Failed to "
636 "update on disk inode for unused "
637 "fallocated blocks, inode could be "
638 "corrupted. Please run fsck");
639 }
640
641 }
642}
643
deee3ce4 644static void fat_evict_inode(struct inode *inode)
1da177e4 645{
91b0abe3 646 truncate_inode_pages_final(&inode->i_data);
deee3ce4
AV		 647 if (!inode->i_nlink) {
648 inode->i_size = 0;
649 fat_truncate_blocks(inode, 0);
b13bb33e
NJ		 650 } else
651 fat_free_eofblocks(inode);
652
deee3ce4 653 invalidate_inode_buffers(inode);
dbd5768f 654 clear_inode(inode);
1da177e4 655 fat_cache_inval_inode(inode);
a993b542 656 fat_detach(inode);
1da177e4
LT		 657}
658
b88a1058
OR		 659static void fat_set_state(struct super_block *sb,
660 unsigned int set, unsigned int force)
661{
662 struct buffer_head *bh;
663 struct fat_boot_sector *b;
d6bd4282 664 struct msdos_sb_info *sbi = MSDOS_SB(sb);
b88a1058
OR		 665
666 /* do not change any thing if mounted read only */
bc98a42c 667 if (sb_rdonly(sb) && !force)
b88a1058
OR		 668 return;
669
670 /* do not change state if fs was dirty */
671 if (sbi->dirty) {
672 /* warn only on set (mount). */
673 if (set)
674 fat_msg(sb, KERN_WARNING, "Volume was not properly "
675 "unmounted. Some data may be corrupt. "
676 "Please run fsck.");
677 return;
678 }
679
680 bh = sb_bread(sb, 0);
681 if (bh == NULL) {
682 fat_msg(sb, KERN_ERR, "unable to read boot sector "
683 "to mark fs as dirty");
684 return;
685 }
686
687 b = (struct fat_boot_sector *) bh->b_data;
688
306790f7 689 if (is_fat32(sbi)) {
b88a1058
OR		 690 if (set)
691 b->fat32.state |= FAT_STATE_DIRTY;
692 else
693 b->fat32.state &= ~FAT_STATE_DIRTY;
694 } else /* fat 16 and 12 */ {
695 if (set)
696 b->fat16.state |= FAT_STATE_DIRTY;
697 else
698 b->fat16.state &= ~FAT_STATE_DIRTY;
699 }
700
701 mark_buffer_dirty(bh);
702 sync_dirty_buffer(bh);
703 brelse(bh);
704}
705
35033ab9
OH		 706static void fat_reset_iocharset(struct fat_mount_options *opts)
707{
708 if (opts->iocharset != fat_default_iocharset) {
709 /* Note: opts->iocharset can be NULL here */
710 kfree(opts->iocharset);
711 opts->iocharset = fat_default_iocharset;
712 }
713}
714
cac45b06
AV		 715static void delayed_free(struct rcu_head *p)
716{
717 struct msdos_sb_info *sbi = container_of(p, struct msdos_sb_info, rcu);
718 unload_nls(sbi->nls_disk);
719 unload_nls(sbi->nls_io);
35033ab9 720 fat_reset_iocharset(&sbi->options);
cac45b06
AV		 721 kfree(sbi);
722}
723
a6bf6b21
OH		 724static void fat_put_super(struct super_block *sb)
725{
726 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1da177e4 727
b88a1058
OR		 728 fat_set_state(sb, 0, 0);
729
020ac5b6 730 iput(sbi->fsinfo_inode);
b522412a
AV		 731 iput(sbi->fat_inode);
732
cac45b06 733 call_rcu(&sbi->rcu, delayed_free);
1da177e4
LT		 734}
735
e18b890b 736static struct kmem_cache *fat_inode_cachep;
1da177e4
LT		 737
738static struct inode *fat_alloc_inode(struct super_block *sb)
739{
740 struct msdos_inode_info *ei;
8f593427 741 ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
1da177e4
LT		 742 if (!ei)
743 return NULL;
58268691
CH		 744
745 init_rwsem(&ei->truncate_lock);
1da177e4
LT		 746 return &ei->vfs_inode;
747}
748
fa0d7e3d 749static void fat_i_callback(struct rcu_head *head)
1da177e4 750{
fa0d7e3d 751 struct inode *inode = container_of(head, struct inode, i_rcu);
1da177e4
LT		 752 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
753}
754
fa0d7e3d
NP		 755static void fat_destroy_inode(struct inode *inode)
756{
757 call_rcu(&inode->i_rcu, fat_i_callback);
758}
759
51cc5068 760static void init_once(void *foo)
1da177e4
LT		 761{
762 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
763
a35afb83
CL		 764 spin_lock_init(&ei->cache_lru_lock);
765 ei->nr_caches = 0;
766 ei->cache_valid_id = FAT_CACHE_VALID + 1;
767 INIT_LIST_HEAD(&ei->cache_lru);
768 INIT_HLIST_NODE(&ei->i_fat_hash);
7669e8fb 769 INIT_HLIST_NODE(&ei->i_dir_hash);
a35afb83 770 inode_init_once(&ei->vfs_inode);
1da177e4
LT		 771}
772
773static int __init fat_init_inodecache(void)
774{
775 fat_inode_cachep = kmem_cache_create("fat_inode_cache",
776 sizeof(struct msdos_inode_info),
fffb60f9 777 0, (SLAB_RECLAIM_ACCOUNT|
5d097056 778 SLAB_MEM_SPREAD|SLAB_ACCOUNT),
20c2df83 779 init_once);
1da177e4
LT		 780 if (fat_inode_cachep == NULL)
781 return -ENOMEM;
782 return 0;
783}
784
785static void __exit fat_destroy_inodecache(void)
786{
8c0a8537
KS		 787 /*
788 * Make sure all delayed rcu free inodes are flushed before we
789 * destroy cache.
790 */
791 rcu_barrier();
1a1d92c1 792 kmem_cache_destroy(fat_inode_cachep);
1da177e4
LT		 793}
794
795static int fat_remount(struct super_block *sb, int *flags, char *data)
796{
b6e8e12c 797 bool new_rdonly;
1da177e4 798 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1751e8a6 799 *flags |= SB_NODIRATIME | (sbi->options.isvfat ? 0 : SB_NOATIME);
b88a1058 800
02b9984d
TT		 801 sync_filesystem(sb);
802
b88a1058 803 /* make sure we update state on remount. */
1751e8a6 804 new_rdonly = *flags & SB_RDONLY;
bc98a42c 805 if (new_rdonly != sb_rdonly(sb)) {
b88a1058
OR		 806 if (new_rdonly)
807 fat_set_state(sb, 0, 0);
808 else
809 fat_set_state(sb, 1, 1);
810 }
1da177e4
LT		 811 return 0;
812}
813
726c3342 814static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
1da177e4 815{
aac49b75
CL		 816 struct super_block *sb = dentry->d_sb;
817 struct msdos_sb_info *sbi = MSDOS_SB(sb);
818 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
1da177e4
LT		 819
820 /* If the count of free cluster is still unknown, counts it here. */
606e423e 821 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
726c3342 822 int err = fat_count_free_clusters(dentry->d_sb);
1da177e4
LT		 823 if (err)
824 return err;
825 }
826
726c3342 827 buf->f_type = dentry->d_sb->s_magic;
1da177e4
LT		 828 buf->f_bsize = sbi->cluster_size;
829 buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
830 buf->f_bfree = sbi->free_clusters;
831 buf->f_bavail = sbi->free_clusters;
aac49b75
CL		 832 buf->f_fsid.val[0] = (u32)id;
833 buf->f_fsid.val[1] = (u32)(id >> 32);
f68e542f
OH		 834 buf->f_namelen =
835 (sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE;
1da177e4
LT		 836
837 return 0;
838}
839
a9185b41 840static int __fat_write_inode(struct inode *inode, int wait)
1da177e4
LT		 841{
842 struct super_block *sb = inode->i_sb;
843 struct msdos_sb_info *sbi = MSDOS_SB(sb);
844 struct buffer_head *bh;
845 struct msdos_dir_entry *raw_entry;
846 loff_t i_pos;
e22a4442
NJ		 847 sector_t blocknr;
848 int err, offset;
1da177e4 849
9ca59f4c
OH		 850 if (inode->i_ino == MSDOS_ROOT_INO)
851 return 0;
852
1da177e4 853retry:
9ca59f4c
OH		 854 i_pos = fat_i_pos_read(sbi, inode);
855 if (!i_pos)
1da177e4
LT		 856 return 0;
857
e22a4442
NJ		 858 fat_get_blknr_offset(sbi, i_pos, &blocknr, &offset);
859 bh = sb_bread(sb, blocknr);
1da177e4 860 if (!bh) {
869f58c0
AF		 861 fat_msg(sb, KERN_ERR, "unable to read inode block "
862 "for updating (i_pos %lld)", i_pos);
5f22ca9b 863 return -EIO;
1da177e4
LT		 864 }
865 spin_lock(&sbi->inode_hash_lock);
866 if (i_pos != MSDOS_I(inode)->i_pos) {
867 spin_unlock(&sbi->inode_hash_lock);
868 brelse(bh);
1da177e4
LT		 869 goto retry;
870 }
871
e22a4442 872 raw_entry = &((struct msdos_dir_entry *) (bh->b_data))[offset];
1da177e4
LT		 873 if (S_ISDIR(inode->i_mode))
874 raw_entry->size = 0;
875 else
876 raw_entry->size = cpu_to_le32(inode->i_size);
9c0aa1b8 877 raw_entry->attr = fat_make_attrs(inode);
a943ed71 878 fat_set_start(raw_entry, MSDOS_I(inode)->i_logstart);
f423420c 879 fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
7decd1cb 880 &raw_entry->date, NULL);
1da177e4 881 if (sbi->options.isvfat) {
62a36c43 882 __le16 atime;
f423420c 883 fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime,
7decd1cb 884 &raw_entry->cdate, &raw_entry->ctime_cs);
f423420c 885 fat_time_unix2fat(sbi, &inode->i_atime, &atime,
7decd1cb 886 &raw_entry->adate, NULL);
1da177e4
LT		 887 }
888 spin_unlock(&sbi->inode_hash_lock);
889 mark_buffer_dirty(bh);
5f22ca9b 890 err = 0;
1da177e4
LT		 891 if (wait)
892 err = sync_dirty_buffer(bh);
893 brelse(bh);
1da177e4
LT		 894 return err;
895}
896
a9185b41
CH		 897static int fat_write_inode(struct inode *inode, struct writeback_control *wbc)
898{
78491189
AB		 899 int err;
900
901 if (inode->i_ino == MSDOS_FSINFO_INO) {
902 struct super_block *sb = inode->i_sb;
903
e40b34c7 904 mutex_lock(&MSDOS_SB(sb)->s_lock);
78491189 905 err = fat_clusters_flush(sb);
e40b34c7 906 mutex_unlock(&MSDOS_SB(sb)->s_lock);
78491189
AB		 907 } else
908 err = __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
909
910 return err;
a9185b41
CH		 911}
912
1da177e4
LT		 913int fat_sync_inode(struct inode *inode)
914{
a9185b41 915 return __fat_write_inode(inode, 1);
1da177e4
LT		 916}
917
7c709d00 918EXPORT_SYMBOL_GPL(fat_sync_inode);
1da177e4 919
34c80b1d 920static int fat_show_options(struct seq_file *m, struct dentry *root);
ee9b6d61 921static const struct super_operations fat_sops = {
1da177e4
LT		 922 .alloc_inode = fat_alloc_inode,
923 .destroy_inode = fat_destroy_inode,
924 .write_inode = fat_write_inode,
deee3ce4 925 .evict_inode = fat_evict_inode,
1da177e4
LT		 926 .put_super = fat_put_super,
927 .statfs = fat_statfs,
1da177e4
LT		 928 .remount_fs = fat_remount,
929
1da177e4
LT		 930 .show_options = fat_show_options,
931};
932
34c80b1d 933static int fat_show_options(struct seq_file *m, struct dentry *root)
1da177e4 934{
34c80b1d 935 struct msdos_sb_info *sbi = MSDOS_SB(root->d_sb);
1da177e4
LT		 936 struct fat_mount_options *opts = &sbi->options;
937 int isvfat = opts->isvfat;
938
170782eb
EB		 939 if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
940 seq_printf(m, ",uid=%u",
941 from_kuid_munged(&init_user_ns, opts->fs_uid));
942 if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
943 seq_printf(m, ",gid=%u",
944 from_kgid_munged(&init_user_ns, opts->fs_gid));
1da177e4
LT		 945 seq_printf(m, ",fmask=%04o", opts->fs_fmask);
946 seq_printf(m, ",dmask=%04o", opts->fs_dmask);
1ae43f82
OH		 947 if (opts->allow_utime)
948 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
1da177e4 949 if (sbi->nls_disk)
c6c20372
DR		 950 /* strip "cp" prefix from displayed option */
951 seq_printf(m, ",codepage=%s", &sbi->nls_disk->charset[2]);
1da177e4
LT		 952 if (isvfat) {
953 if (sbi->nls_io)
954 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
955
956 switch (opts->shortname) {
957 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
958 seq_puts(m, ",shortname=win95");
959 break;
960 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
961 seq_puts(m, ",shortname=winnt");
962 break;
963 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
964 seq_puts(m, ",shortname=mixed");
965 break;
966 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
95523475 967 seq_puts(m, ",shortname=lower");
1da177e4
LT		 968 break;
969 default:
970 seq_puts(m, ",shortname=unknown");
971 break;
972 }
973 }
974 if (opts->name_check != 'n')
975 seq_printf(m, ",check=%c", opts->name_check);
28ec039c
OH		 976 if (opts->usefree)
977 seq_puts(m, ",usefree");
1da177e4
LT		 978 if (opts->quiet)
979 seq_puts(m, ",quiet");
980 if (opts->showexec)
981 seq_puts(m, ",showexec");
982 if (opts->sys_immutable)
983 seq_puts(m, ",sys_immutable");
984 if (!isvfat) {
985 if (opts->dotsOK)
986 seq_puts(m, ",dotsOK=yes");
987 if (opts->nocase)
988 seq_puts(m, ",nocase");
989 } else {
990 if (opts->utf8)
991 seq_puts(m, ",utf8");
992 if (opts->unicode_xlate)
993 seq_puts(m, ",uni_xlate");
994 if (!opts->numtail)
995 seq_puts(m, ",nonumtail");
dfc209c0
OH		 996 if (opts->rodir)
997 seq_puts(m, ",rodir");
1da177e4 998 }
dfc209c0 999 if (opts->flush)
c1fca3b6 1000 seq_puts(m, ",flush");
58156c8f
JK		 1001 if (opts->tz_set) {
1002 if (opts->time_offset)
1003 seq_printf(m, ",time_offset=%d", opts->time_offset);
1004 else
1005 seq_puts(m, ",tz=UTC");
1006 }
85c78591
DK		 1007 if (opts->errors == FAT_ERRORS_CONT)
1008 seq_puts(m, ",errors=continue");
1009 else if (opts->errors == FAT_ERRORS_PANIC)
1010 seq_puts(m, ",errors=panic");
1011 else
1012 seq_puts(m, ",errors=remount-ro");
2628b7a6
NJ		 1013 if (opts->nfs == FAT_NFS_NOSTALE_RO)
1014 seq_puts(m, ",nfs=nostale_ro");
1015 else if (opts->nfs)
1016 seq_puts(m, ",nfs=stale_rw");
681142f9
CH		 1017 if (opts->discard)
1018 seq_puts(m, ",discard");
190a8843
CM		 1019 if (opts->dos1xfloppy)
1020 seq_puts(m, ",dos1xfloppy");
1da177e4
LT		 1021
1022 return 0;
1023}
1024
1025enum {
1026 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
1ae43f82
OH		 1027 Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
1028 Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
1029 Opt_immutable, Opt_dots, Opt_nodots,
1da177e4
LT		 1030 Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
1031 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
1032 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
d7a83c0f 1033 Opt_obsolete, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
58156c8f 1034 Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_time_offset,
190a8843 1035 Opt_nfs_stale_rw, Opt_nfs_nostale_ro, Opt_err, Opt_dos1xfloppy,
1da177e4
LT		 1036};
1037
a447c093 1038static const match_table_t fat_tokens = {
1da177e4
LT		 1039 {Opt_check_r, "check=relaxed"},
1040 {Opt_check_s, "check=strict"},
1041 {Opt_check_n, "check=normal"},
1042 {Opt_check_r, "check=r"},
1043 {Opt_check_s, "check=s"},
1044 {Opt_check_n, "check=n"},
1045 {Opt_uid, "uid=%u"},
1046 {Opt_gid, "gid=%u"},
1047 {Opt_umask, "umask=%o"},
1048 {Opt_dmask, "dmask=%o"},
1049 {Opt_fmask, "fmask=%o"},
1ae43f82 1050 {Opt_allow_utime, "allow_utime=%o"},
1da177e4 1051 {Opt_codepage, "codepage=%u"},
28ec039c 1052 {Opt_usefree, "usefree"},
1da177e4
LT		 1053 {Opt_nocase, "nocase"},
1054 {Opt_quiet, "quiet"},
1055 {Opt_showexec, "showexec"},
1056 {Opt_debug, "debug"},
1057 {Opt_immutable, "sys_immutable"},
85c78591
DK		 1058 {Opt_flush, "flush"},
1059 {Opt_tz_utc, "tz=UTC"},
58156c8f 1060 {Opt_time_offset, "time_offset=%d"},
85c78591
DK		 1061 {Opt_err_cont, "errors=continue"},
1062 {Opt_err_panic, "errors=panic"},
1063 {Opt_err_ro, "errors=remount-ro"},
681142f9 1064 {Opt_discard, "discard"},
2628b7a6
NJ		 1065 {Opt_nfs_stale_rw, "nfs"},
1066 {Opt_nfs_stale_rw, "nfs=stale_rw"},
1067 {Opt_nfs_nostale_ro, "nfs=nostale_ro"},
190a8843 1068 {Opt_dos1xfloppy, "dos1xfloppy"},
d7a83c0f
GU		 1069 {Opt_obsolete, "conv=binary"},
1070 {Opt_obsolete, "conv=text"},
1071 {Opt_obsolete, "conv=auto"},
1072 {Opt_obsolete, "conv=b"},
1073 {Opt_obsolete, "conv=t"},
1074 {Opt_obsolete, "conv=a"},
1075 {Opt_obsolete, "fat=%u"},
1076 {Opt_obsolete, "blocksize=%u"},
1077 {Opt_obsolete, "cvf_format=%20s"},
1078 {Opt_obsolete, "cvf_options=%100s"},
1079 {Opt_obsolete, "posix"},
ae78bf9c 1080 {Opt_err, NULL},
1da177e4 1081};
a447c093 1082static const match_table_t msdos_tokens = {
1da177e4
LT		 1083 {Opt_nodots, "nodots"},
1084 {Opt_nodots, "dotsOK=no"},
1085 {Opt_dots, "dots"},
1086 {Opt_dots, "dotsOK=yes"},
1087 {Opt_err, NULL}
1088};
a447c093 1089static const match_table_t vfat_tokens = {
1da177e4
LT		 1090 {Opt_charset, "iocharset=%s"},
1091 {Opt_shortname_lower, "shortname=lower"},
1092 {Opt_shortname_win95, "shortname=win95"},
1093 {Opt_shortname_winnt, "shortname=winnt"},
1094 {Opt_shortname_mixed, "shortname=mixed"},
1095 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */
1096 {Opt_utf8_no, "utf8=no"},
1097 {Opt_utf8_no, "utf8=false"},
1098 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */
1099 {Opt_utf8_yes, "utf8=yes"},
1100 {Opt_utf8_yes, "utf8=true"},
1101 {Opt_utf8_yes, "utf8"},
1102 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */
1103 {Opt_uni_xl_no, "uni_xlate=no"},
1104 {Opt_uni_xl_no, "uni_xlate=false"},
1105 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */
1106 {Opt_uni_xl_yes, "uni_xlate=yes"},
1107 {Opt_uni_xl_yes, "uni_xlate=true"},
1108 {Opt_uni_xl_yes, "uni_xlate"},
1109 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */
1110 {Opt_nonumtail_no, "nonumtail=no"},
1111 {Opt_nonumtail_no, "nonumtail=false"},
1112 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */
1113 {Opt_nonumtail_yes, "nonumtail=yes"},
1114 {Opt_nonumtail_yes, "nonumtail=true"},
1115 {Opt_nonumtail_yes, "nonumtail"},
dfc209c0 1116 {Opt_rodir, "rodir"},
1da177e4
LT		 1117 {Opt_err, NULL}
1118};
1119
869f58c0
AF		 1120static int parse_options(struct super_block *sb, char *options, int is_vfat,
1121 int silent, int *debug, struct fat_mount_options *opts)
1da177e4
LT		 1122{
1123 char *p;
1124 substring_t args[MAX_OPT_ARGS];
1125 int option;
1126 char *iocharset;
1127
1128 opts->isvfat = is_vfat;
1129
f0ce7ee3
DH		 1130 opts->fs_uid = current_uid();
1131 opts->fs_gid = current_gid();
3e107603 1132 opts->fs_fmask = opts->fs_dmask = current_umask();
1ae43f82 1133 opts->allow_utime = -1;
1da177e4 1134 opts->codepage = fat_default_codepage;
35033ab9 1135 fat_reset_iocharset(opts);
dfc209c0 1136 if (is_vfat) {
95523475 1137 opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95;
dfc209c0
OH		 1138 opts->rodir = 0;
1139 } else {
1da177e4 1140 opts->shortname = 0;
dfc209c0
OH		 1141 opts->rodir = 1;
1142 }
1da177e4
LT		 1143 opts->name_check = 'n';
1144 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0;
38739380 1145 opts->unicode_xlate = 0;
1da177e4 1146 opts->numtail = 1;
28ec039c 1147 opts->usefree = opts->nocase = 0;
58156c8f 1148 opts->tz_set = 0;
7669e8fb 1149 opts->nfs = 0;
85c78591 1150 opts->errors = FAT_ERRORS_RO;
1da177e4
LT		 1151 *debug = 0;
1152
38739380
MS		 1153 opts->utf8 = IS_ENABLED(CONFIG_FAT_DEFAULT_UTF8) && is_vfat;
1154
1da177e4 1155 if (!options)
8d44d974 1156 goto out;
1da177e4
LT		 1157
1158 while ((p = strsep(&options, ",")) != NULL) {
1159 int token;
1160 if (!*p)
1161 continue;
1162
1163 token = match_token(p, fat_tokens, args);
1164 if (token == Opt_err) {
1165 if (is_vfat)
1166 token = match_token(p, vfat_tokens, args);
1167 else
1168 token = match_token(p, msdos_tokens, args);
1169 }
1170 switch (token) {
1171 case Opt_check_s:
1172 opts->name_check = 's';
1173 break;
1174 case Opt_check_r:
1175 opts->name_check = 'r';
1176 break;
1177 case Opt_check_n:
1178 opts->name_check = 'n';
1179 break;
28ec039c
OH		 1180 case Opt_usefree:
1181 opts->usefree = 1;
1182 break;
1da177e4
LT		 1183 case Opt_nocase:
1184 if (!is_vfat)
1185 opts->nocase = 1;
1186 else {
1187 /* for backward compatibility */
1188 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1189 | VFAT_SFN_CREATE_WIN95;
1190 }
1191 break;
1192 case Opt_quiet:
1193 opts->quiet = 1;
1194 break;
1195 case Opt_showexec:
1196 opts->showexec = 1;
1197 break;
1198 case Opt_debug:
1199 *debug = 1;
1200 break;
1201 case Opt_immutable:
1202 opts->sys_immutable = 1;
1203 break;
1204 case Opt_uid:
1205 if (match_int(&args[0], &option))
5b3d5aea 1206 return -EINVAL;
170782eb
EB		 1207 opts->fs_uid = make_kuid(current_user_ns(), option);
1208 if (!uid_valid(opts->fs_uid))
5b3d5aea 1209 return -EINVAL;
1da177e4
LT		 1210 break;
1211 case Opt_gid:
1212 if (match_int(&args[0], &option))
5b3d5aea 1213 return -EINVAL;
170782eb
EB		 1214 opts->fs_gid = make_kgid(current_user_ns(), option);
1215 if (!gid_valid(opts->fs_gid))
5b3d5aea 1216 return -EINVAL;
1da177e4
LT		 1217 break;
1218 case Opt_umask:
1219 if (match_octal(&args[0], &option))
5b3d5aea 1220 return -EINVAL;
1da177e4
LT		 1221 opts->fs_fmask = opts->fs_dmask = option;
1222 break;
1223 case Opt_dmask:
1224 if (match_octal(&args[0], &option))
5b3d5aea 1225 return -EINVAL;
1da177e4
LT		 1226 opts->fs_dmask = option;
1227 break;
1228 case Opt_fmask:
1229 if (match_octal(&args[0], &option))
5b3d5aea 1230 return -EINVAL;
1da177e4
LT		 1231 opts->fs_fmask = option;
1232 break;
1ae43f82
OH		 1233 case Opt_allow_utime:
1234 if (match_octal(&args[0], &option))
5b3d5aea 1235 return -EINVAL;
1ae43f82
OH		 1236 opts->allow_utime = option & (S_IWGRP | S_IWOTH);
1237 break;
1da177e4
LT		 1238 case Opt_codepage:
1239 if (match_int(&args[0], &option))
5b3d5aea 1240 return -EINVAL;
1da177e4
LT		 1241 opts->codepage = option;
1242 break;
ae78bf9c
CM		 1243 case Opt_flush:
1244 opts->flush = 1;
1245 break;
58156c8f
JK		 1246 case Opt_time_offset:
1247 if (match_int(&args[0], &option))
5b3d5aea 1248 return -EINVAL;
a513d869
JK		 1249 /*
1250 * GMT+-12 zones may have DST corrections so at least
1251 * 13 hours difference is needed. Make the limit 24
1252 * just in case someone invents something unusual.
1253 */
1254 if (option < -24 * 60 || option > 24 * 60)
5b3d5aea 1255 return -EINVAL;
58156c8f
JK		 1256 opts->tz_set = 1;
1257 opts->time_offset = option;
1258 break;
b271e067 1259 case Opt_tz_utc:
58156c8f
JK		 1260 opts->tz_set = 1;
1261 opts->time_offset = 0;
b271e067 1262 break;
85c78591
DK		 1263 case Opt_err_cont:
1264 opts->errors = FAT_ERRORS_CONT;
1265 break;
1266 case Opt_err_panic:
1267 opts->errors = FAT_ERRORS_PANIC;
1268 break;
1269 case Opt_err_ro:
1270 opts->errors = FAT_ERRORS_RO;
1271 break;
2628b7a6
NJ		 1272 case Opt_nfs_stale_rw:
1273 opts->nfs = FAT_NFS_STALE_RW;
1274 break;
1275 case Opt_nfs_nostale_ro:
1276 opts->nfs = FAT_NFS_NOSTALE_RO;
1277 break;
190a8843
CM		 1278 case Opt_dos1xfloppy:
1279 opts->dos1xfloppy = 1;
1280 break;
1da177e4
LT		 1281
1282 /* msdos specific */
1283 case Opt_dots:
1284 opts->dotsOK = 1;
1285 break;
1286 case Opt_nodots:
1287 opts->dotsOK = 0;
1288 break;
1289
1290 /* vfat specific */
1291 case Opt_charset:
35033ab9 1292 fat_reset_iocharset(opts);
1da177e4
LT		 1293 iocharset = match_strdup(&args[0]);
1294 if (!iocharset)
1295 return -ENOMEM;
1296 opts->iocharset = iocharset;
1297 break;
1298 case Opt_shortname_lower:
1299 opts->shortname = VFAT_SFN_DISPLAY_LOWER
1300 | VFAT_SFN_CREATE_WIN95;
1301 break;
1302 case Opt_shortname_win95:
1303 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1304 | VFAT_SFN_CREATE_WIN95;
1305 break;
1306 case Opt_shortname_winnt:
1307 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1308 | VFAT_SFN_CREATE_WINNT;
1309 break;
1310 case Opt_shortname_mixed:
1311 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1312 | VFAT_SFN_CREATE_WIN95;
1313 break;
1314 case Opt_utf8_no: /* 0 or no or false */
1315 opts->utf8 = 0;
1316 break;
1317 case Opt_utf8_yes: /* empty or 1 or yes or true */
1318 opts->utf8 = 1;
1319 break;
1320 case Opt_uni_xl_no: /* 0 or no or false */
1321 opts->unicode_xlate = 0;
1322 break;
1323 case Opt_uni_xl_yes: /* empty or 1 or yes or true */
1324 opts->unicode_xlate = 1;
1325 break;
1326 case Opt_nonumtail_no: /* 0 or no or false */
1327 opts->numtail = 1; /* negated option */
1328 break;
1329 case Opt_nonumtail_yes: /* empty or 1 or yes or true */
1330 opts->numtail = 0; /* negated option */
1331 break;
dfc209c0
OH		 1332 case Opt_rodir:
1333 opts->rodir = 1;
1334 break;
681142f9
CH		 1335 case Opt_discard:
1336 opts->discard = 1;
1337 break;
1da177e4
LT		 1338
1339 /* obsolete mount options */
d7a83c0f 1340 case Opt_obsolete:
869f58c0
AF		 1341 fat_msg(sb, KERN_INFO, "\"%s\" option is obsolete, "
1342 "not supported now", p);
1da177e4
LT		 1343 break;
1344 /* unknown option */
1345 default:
41a34a4f 1346 if (!silent) {
869f58c0
AF		 1347 fat_msg(sb, KERN_ERR,
1348 "Unrecognized mount option \"%s\" "
1349 "or missing value", p);
41a34a4f 1350 }
1da177e4
LT		 1351 return -EINVAL;
1352 }
1353 }
8d44d974
OH		 1354
1355out:
4de151d8 1356 /* UTF-8 doesn't provide FAT semantics */
1da177e4 1357 if (!strcmp(opts->iocharset, "utf8")) {
186b5370 1358 fat_msg(sb, KERN_WARNING, "utf8 is not a recommended IO charset"
8d44d974 1359 " for FAT filesystems, filesystem will be "
186b5370 1360 "case sensitive!");
1da177e4
LT		 1361 }
1362
1ae43f82
OH		 1363 /* If user doesn't specify allow_utime, it's initialized from dmask. */
1364 if (opts->allow_utime == (unsigned short)-1)
1365 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1da177e4
LT		 1366 if (opts->unicode_xlate)
1367 opts->utf8 = 0;
ea3983ac 1368 if (opts->nfs == FAT_NFS_NOSTALE_RO) {
1751e8a6 1369 sb->s_flags |= SB_RDONLY;
ea3983ac
NJ		 1370 sb->s_export_op = &fat_export_ops_nostale;
1371 }
1da177e4
LT		 1372
1373 return 0;
1374}
1375
c0d0e351
OH		 1376static void fat_dummy_inode_init(struct inode *inode)
1377{
1378 /* Initialize this dummy inode to work as no-op. */
1379 MSDOS_I(inode)->mmu_private = 0;
1380 MSDOS_I(inode)->i_start = 0;
1381 MSDOS_I(inode)->i_logstart = 0;
1382 MSDOS_I(inode)->i_attrs = 0;
1383 MSDOS_I(inode)->i_pos = 0;
1384}
1385
1da177e4
LT		 1386static int fat_read_root(struct inode *inode)
1387{
a40a7d9d 1388 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
1da177e4
LT		 1389 int error;
1390
ea3983ac 1391 MSDOS_I(inode)->i_pos = MSDOS_ROOT_INO;
1da177e4
LT		 1392 inode->i_uid = sbi->options.fs_uid;
1393 inode->i_gid = sbi->options.fs_gid;
2489dbab 1394 inode_inc_iversion(inode);
1da177e4 1395 inode->i_generation = 0;
9c0aa1b8 1396 inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
1da177e4
LT		 1397 inode->i_op = sbi->dir_ops;
1398 inode->i_fop = &fat_dir_operations;
306790f7 1399 if (is_fat32(sbi)) {
1da177e4
LT		 1400 MSDOS_I(inode)->i_start = sbi->root_cluster;
1401 error = fat_calc_dir_size(inode);
1402 if (error < 0)
1403 return error;
1404 } else {
1405 MSDOS_I(inode)->i_start = 0;
1406 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1407 }
1da177e4
LT		 1408 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1409 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1410 MSDOS_I(inode)->i_logstart = 0;
1411 MSDOS_I(inode)->mmu_private = inode->i_size;
1412
9c0aa1b8 1413 fat_save_attrs(inode, ATTR_DIR);
1da177e4
LT		 1414 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1415 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
bfe86848 1416 set_nlink(inode, fat_subdirs(inode)+2);
1da177e4
LT		 1417
1418 return 0;
1419}
1420
7b92d03c
OH		 1421static unsigned long calc_fat_clusters(struct super_block *sb)
1422{
1423 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1424
1425 /* Divide first to avoid overflow */
306790f7 1426 if (!is_fat12(sbi)) {
7b92d03c
OH		 1427 unsigned long ent_per_sec = sb->s_blocksize * 8 / sbi->fat_bits;
1428 return ent_per_sec * sbi->fat_length;
1429 }
1430
1431 return sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1432}
1433
190a8843
CM		 1434static bool fat_bpb_is_zero(struct fat_boot_sector *b)
1435{
1436 if (get_unaligned_le16(&b->sector_size))
1437 return false;
1438 if (b->sec_per_clus)
1439 return false;
1440 if (b->reserved)
1441 return false;
1442 if (b->fats)
1443 return false;
1444 if (get_unaligned_le16(&b->dir_entries))
1445 return false;
1446 if (get_unaligned_le16(&b->sectors))
1447 return false;
1448 if (b->media)
1449 return false;
1450 if (b->fat_length)
1451 return false;
1452 if (b->secs_track)
1453 return false;
1454 if (b->heads)
1455 return false;
1456 return true;
1457}
1458
1459static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b,
1460 int silent, struct fat_bios_param_block *bpb)
1461{
1462 int error = -EINVAL;
1463
1464 /* Read in BPB ... */
1465 memset(bpb, 0, sizeof(*bpb));
1466 bpb->fat_sector_size = get_unaligned_le16(&b->sector_size);
1467 bpb->fat_sec_per_clus = b->sec_per_clus;
1468 bpb->fat_reserved = le16_to_cpu(b->reserved);
1469 bpb->fat_fats = b->fats;
1470 bpb->fat_dir_entries = get_unaligned_le16(&b->dir_entries);
1471 bpb->fat_sectors = get_unaligned_le16(&b->sectors);
1472 bpb->fat_fat_length = le16_to_cpu(b->fat_length);
1473 bpb->fat_total_sect = le32_to_cpu(b->total_sect);
1474
1475 bpb->fat16_state = b->fat16.state;
1476 bpb->fat16_vol_id = get_unaligned_le32(b->fat16.vol_id);
1477
1478 bpb->fat32_length = le32_to_cpu(b->fat32.length);
1479 bpb->fat32_root_cluster = le32_to_cpu(b->fat32.root_cluster);
1480 bpb->fat32_info_sector = le16_to_cpu(b->fat32.info_sector);
1481 bpb->fat32_state = b->fat32.state;
1482 bpb->fat32_vol_id = get_unaligned_le32(b->fat32.vol_id);
1483
1484 /* Validate this looks like a FAT filesystem BPB */
1485 if (!bpb->fat_reserved) {
1486 if (!silent)
1487 fat_msg(sb, KERN_ERR,
1488 "bogus number of reserved sectors");
1489 goto out;
1490 }
1491 if (!bpb->fat_fats) {
1492 if (!silent)
1493 fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
1494 goto out;
1495 }
1496
1497 /*
1498 * Earlier we checked here that b->secs_track and b->head are nonzero,
1499 * but it turns out valid FAT filesystems can have zero there.
1500 */
1501
1502 if (!fat_valid_media(b->media)) {
1503 if (!silent)
1504 fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
1505 (unsigned)b->media);
1506 goto out;
1507 }
1508
1509 if (!is_power_of_2(bpb->fat_sector_size)
1510 || (bpb->fat_sector_size < 512)
1511 || (bpb->fat_sector_size > 4096)) {
1512 if (!silent)
1513 fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
1514 (unsigned)bpb->fat_sector_size);
1515 goto out;
1516 }
1517
1518 if (!is_power_of_2(bpb->fat_sec_per_clus)) {
1519 if (!silent)
1520 fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
1521 (unsigned)bpb->fat_sec_per_clus);
1522 goto out;
1523 }
1524
1525 error = 0;
1526
1527out:
1528 return error;
1529}
1530
1531static int fat_read_static_bpb(struct super_block *sb,
1532 struct fat_boot_sector *b, int silent,
1533 struct fat_bios_param_block *bpb)
1534{
1535 static const char *notdos1x = "This doesn't look like a DOS 1.x volume";
1536
1537 struct fat_floppy_defaults *fdefaults = NULL;
1538 int error = -EINVAL;
1539 sector_t bd_sects;
1540 unsigned i;
1541
1542 bd_sects = i_size_read(sb->s_bdev->bd_inode) / SECTOR_SIZE;
1543
1544 /* 16-bit DOS 1.x reliably wrote bootstrap short-jmp code */
1545 if (b->ignored[0] != 0xeb || b->ignored[2] != 0x90) {
1546 if (!silent)
1547 fat_msg(sb, KERN_ERR,
1548 "%s; no bootstrapping code", notdos1x);
1549 goto out;
1550 }
1551
1552 /*
1553 * If any value in this region is non-zero, it isn't archaic
1554 * DOS.
1555 */
1556 if (!fat_bpb_is_zero(b)) {
1557 if (!silent)
1558 fat_msg(sb, KERN_ERR,
1559 "%s; DOS 2.x BPB is non-zero", notdos1x);
1560 goto out;
1561 }
1562
1563 for (i = 0; i < ARRAY_SIZE(floppy_defaults); i++) {
1564 if (floppy_defaults[i].nr_sectors == bd_sects) {
1565 fdefaults = &floppy_defaults[i];
1566 break;
1567 }
1568 }
1569
1570 if (fdefaults == NULL) {
1571 if (!silent)
1572 fat_msg(sb, KERN_WARNING,
1573 "This looks like a DOS 1.x volume, but isn't a recognized floppy size (%llu sectors)",
1574 (u64)bd_sects);
1575 goto out;
1576 }
1577
1578 if (!silent)
1579 fat_msg(sb, KERN_INFO,
1580 "This looks like a DOS 1.x volume; assuming default BPB values");
1581
1582 memset(bpb, 0, sizeof(*bpb));
1583 bpb->fat_sector_size = SECTOR_SIZE;
1584 bpb->fat_sec_per_clus = fdefaults->sec_per_clus;
1585 bpb->fat_reserved = 1;
1586 bpb->fat_fats = 2;
1587 bpb->fat_dir_entries = fdefaults->dir_entries;
1588 bpb->fat_sectors = fdefaults->nr_sectors;
1589 bpb->fat_fat_length = fdefaults->fat_length;
1590
1591 error = 0;
1592
1593out:
1594 return error;
1595}
1596
1da177e4
LT		 1597/*
1598 * Read the super block of an MS-DOS FS.
1599 */
384f5c96 1600int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
3d23985d 1601 void (*setup)(struct super_block *))
1da177e4 1602{
b522412a 1603 struct inode *root_inode = NULL, *fat_inode = NULL;
020ac5b6 1604 struct inode *fsinfo_inode = NULL;
1da177e4 1605 struct buffer_head *bh;
190a8843 1606 struct fat_bios_param_block bpb;
1da177e4
LT		 1607 struct msdos_sb_info *sbi;
1608 u16 logical_sector_size;
1609 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1610 int debug;
1da177e4
LT		 1611 long error;
1612 char buf[50];
1613
8f593427
LT		 1614 /*
1615 * GFP_KERNEL is ok here, because while we do hold the
dcc381e8 1616 * superblock lock, memory pressure can't call back into
8f593427
LT		 1617 * the filesystem, since we're only just about to mount
1618 * it and have no inodes etc active!
1619 */
f8314dc6 1620 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1da177e4
LT		 1621 if (!sbi)
1622 return -ENOMEM;
1623 sb->s_fs_info = sbi;
1da177e4 1624
1751e8a6 1625 sb->s_flags |= SB_NODIRATIME;
1da177e4
LT		 1626 sb->s_magic = MSDOS_SUPER_MAGIC;
1627 sb->s_op = &fat_sops;
1628 sb->s_export_op = &fat_export_ops;
6bb885ec
FS		 1629 /*
1630 * fat timestamps are complex and truncated by fat itself, so
1631 * we set 1 here to be fast
1632 */
1633 sb->s_time_gran = 1;
8fceb4e0 1634 mutex_init(&sbi->nfs_build_inode_lock);
aaa04b48
OH		 1635 ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
1636 DEFAULT_RATELIMIT_BURST);
1da177e4 1637
869f58c0 1638 error = parse_options(sb, data, isvfat, silent, &debug, &sbi->options);
1da177e4
LT		 1639 if (error)
1640 goto out_fail;
1641
3d23985d
AV		 1642 setup(sb); /* flavour-specific stuff that needs options */
1643
1da177e4
LT		 1644 error = -EIO;
1645 sb_min_blocksize(sb, 512);
1646 bh = sb_bread(sb, 0);
1647 if (bh == NULL) {
869f58c0 1648 fat_msg(sb, KERN_ERR, "unable to read boot sector");
1da177e4
LT		 1649 goto out_fail;
1650 }
1651
190a8843
CM		 1652 error = fat_read_bpb(sb, (struct fat_boot_sector *)bh->b_data, silent,
1653 &bpb);
1654 if (error == -EINVAL && sbi->options.dos1xfloppy)
1655 error = fat_read_static_bpb(sb,
1656 (struct fat_boot_sector *)bh->b_data, silent, &bpb);
1657 brelse(bh);
1da177e4 1658
190a8843 1659 if (error == -EINVAL)
1da177e4 1660 goto out_invalid;
190a8843
CM		 1661 else if (error)
1662 goto out_fail;
1da177e4 1663
190a8843
CM		 1664 logical_sector_size = bpb.fat_sector_size;
1665 sbi->sec_per_clus = bpb.fat_sec_per_clus;
1666
1667 error = -EIO;
1da177e4 1668 if (logical_sector_size < sb->s_blocksize) {
869f58c0
AF		 1669 fat_msg(sb, KERN_ERR, "logical sector size too small for device"
1670 " (logical sector size = %u)", logical_sector_size);
1da177e4
LT		 1671 goto out_fail;
1672 }
190a8843 1673
1da177e4 1674 if (logical_sector_size > sb->s_blocksize) {
190a8843 1675 struct buffer_head *bh_resize;
1da177e4
LT		 1676
1677 if (!sb_set_blocksize(sb, logical_sector_size)) {
869f58c0 1678 fat_msg(sb, KERN_ERR, "unable to set blocksize %u",
1da177e4
LT		 1679 logical_sector_size);
1680 goto out_fail;
1681 }
190a8843
CM		 1682
1683 /* Verify that the larger boot sector is fully readable */
1684 bh_resize = sb_bread(sb, 0);
1685 if (bh_resize == NULL) {
869f58c0
AF		 1686 fat_msg(sb, KERN_ERR, "unable to read boot sector"
1687 " (logical sector size = %lu)",
1da177e4
LT		 1688 sb->s_blocksize);
1689 goto out_fail;
1690 }
190a8843 1691 brelse(bh_resize);
1da177e4
LT		 1692 }
1693
e40b34c7 1694 mutex_init(&sbi->s_lock);
1da177e4
LT		 1695 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1696 sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
190a8843 1697 sbi->fats = bpb.fat_fats;
1da177e4 1698 sbi->fat_bits = 0; /* Don't know yet */
190a8843
CM		 1699 sbi->fat_start = bpb.fat_reserved;
1700 sbi->fat_length = bpb.fat_fat_length;
1da177e4
LT		 1701 sbi->root_cluster = 0;
1702 sbi->free_clusters = -1; /* Don't know yet */
606e423e 1703 sbi->free_clus_valid = 0;
1da177e4 1704 sbi->prev_free = FAT_START_ENT;
710d4403 1705 sb->s_maxbytes = 0xffffffff;
1da177e4 1706
190a8843 1707 if (!sbi->fat_length && bpb.fat32_length) {
1da177e4
LT		 1708 struct fat_boot_fsinfo *fsinfo;
1709 struct buffer_head *fsinfo_bh;
1710
1711 /* Must be FAT32 */
1712 sbi->fat_bits = 32;
190a8843
CM		 1713 sbi->fat_length = bpb.fat32_length;
1714 sbi->root_cluster = bpb.fat32_root_cluster;
1da177e4 1715
1da177e4 1716 /* MC - if info_sector is 0, don't multiply by 0 */
190a8843 1717 sbi->fsinfo_sector = bpb.fat32_info_sector;
1da177e4
LT		 1718 if (sbi->fsinfo_sector == 0)
1719 sbi->fsinfo_sector = 1;
1720
1721 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1722 if (fsinfo_bh == NULL) {
869f58c0
AF		 1723 fat_msg(sb, KERN_ERR, "bread failed, FSINFO block"
1724 " (sector = %lu)", sbi->fsinfo_sector);
1da177e4
LT		 1725 goto out_fail;
1726 }
1727
1728 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1729 if (!IS_FSINFO(fsinfo)) {
869f58c0
AF		 1730 fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: "
1731 "0x%08x, 0x%08x (sector = %lu)",
1da177e4
LT		 1732 le32_to_cpu(fsinfo->signature1),
1733 le32_to_cpu(fsinfo->signature2),
1734 sbi->fsinfo_sector);
1735 } else {
28ec039c 1736 if (sbi->options.usefree)
606e423e
OH		 1737 sbi->free_clus_valid = 1;
1738 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1da177e4
LT		 1739 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1740 }
1741
1742 brelse(fsinfo_bh);
1743 }
1744
6e5b93ee 1745 /* interpret volume ID as a little endian 32 bit integer */
306790f7 1746 if (is_fat32(sbi))
190a8843 1747 sbi->vol_id = bpb.fat32_vol_id;
6e5b93ee 1748 else /* fat 16 or 12 */
190a8843 1749 sbi->vol_id = bpb.fat16_vol_id;
6e5b93ee 1750
1da177e4
LT		 1751 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1752 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1753
1754 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
190a8843 1755 sbi->dir_entries = bpb.fat_dir_entries;
1da177e4
LT		 1756 if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1757 if (!silent)
34df1174 1758 fat_msg(sb, KERN_ERR, "bogus number of directory entries"
869f58c0 1759 " (%u)", sbi->dir_entries);
1da177e4
LT		 1760 goto out_invalid;
1761 }
1762
1763 rootdir_sectors = sbi->dir_entries
1764 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1765 sbi->data_start = sbi->dir_start + rootdir_sectors;
190a8843 1766 total_sectors = bpb.fat_sectors;
1da177e4 1767 if (total_sectors == 0)
190a8843 1768 total_sectors = bpb.fat_total_sect;
1da177e4
LT		 1769
1770 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1771
306790f7 1772 if (!is_fat32(sbi))
1da177e4
LT		 1773 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1774
b88a1058 1775 /* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
306790f7 1776 if (is_fat32(sbi))
190a8843 1777 sbi->dirty = bpb.fat32_state & FAT_STATE_DIRTY;
b88a1058 1778 else /* fat 16 or 12 */
190a8843 1779 sbi->dirty = bpb.fat16_state & FAT_STATE_DIRTY;
b88a1058 1780
1da177e4 1781 /* check that FAT table does not overflow */
7b92d03c 1782 fat_clusters = calc_fat_clusters(sb);
1da177e4 1783 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
d19dc016 1784 if (total_clusters > max_fat(sb)) {
1da177e4 1785 if (!silent)
869f58c0 1786 fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
1da177e4 1787 total_clusters);
1da177e4
LT		 1788 goto out_invalid;
1789 }
1790
1791 sbi->max_cluster = total_clusters + FAT_START_ENT;
1792 /* check the free_clusters, it's not necessarily correct */
1793 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1794 sbi->free_clusters = -1;
1795 /* check the prev_free, it's not necessarily correct */
1796 sbi->prev_free %= sbi->max_cluster;
1797 if (sbi->prev_free < FAT_START_ENT)
1798 sbi->prev_free = FAT_START_ENT;
1799
1da177e4
LT		 1800 /* set up enough so that it can read an inode */
1801 fat_hash_init(sb);
7669e8fb 1802 dir_hash_init(sb);
1da177e4
LT		 1803 fat_ent_access_init(sb);
1804
1805 /*
b553337a
CT		 1806 * The low byte of the first FAT entry must have the same value as
1807 * the media field of the boot sector. But in real world, too many
1808 * devices are writing wrong values. So, removed that validity check.
1da177e4 1809 *
b553337a
CT		 1810 * The removed check compared the first FAT entry to a value dependent
1811 * on the media field like this:
1812 * == (0x0F00 | media), for FAT12
1813 * == (0XFF00 | media), for FAT16
1814 * == (0x0FFFFF | media), for FAT32
1da177e4
LT		 1815 */
1816
1817 error = -EINVAL;
1818 sprintf(buf, "cp%d", sbi->options.codepage);
1819 sbi->nls_disk = load_nls(buf);
1820 if (!sbi->nls_disk) {
869f58c0 1821 fat_msg(sb, KERN_ERR, "codepage %s not found", buf);
1da177e4
LT		 1822 goto out_fail;
1823 }
1824
1825 /* FIXME: utf8 is using iocharset for upper/lower conversion */
1826 if (sbi->options.isvfat) {
1827 sbi->nls_io = load_nls(sbi->options.iocharset);
1828 if (!sbi->nls_io) {
869f58c0 1829 fat_msg(sb, KERN_ERR, "IO charset %s not found",
1da177e4
LT		 1830 sbi->options.iocharset);
1831 goto out_fail;
1832 }
1833 }
1834
1835 error = -ENOMEM;
b522412a
AV		 1836 fat_inode = new_inode(sb);
1837 if (!fat_inode)
1838 goto out_fail;
c0d0e351 1839 fat_dummy_inode_init(fat_inode);
b522412a 1840 sbi->fat_inode = fat_inode;
020ac5b6
AB		 1841
1842 fsinfo_inode = new_inode(sb);
1843 if (!fsinfo_inode)
1844 goto out_fail;
c0d0e351 1845 fat_dummy_inode_init(fsinfo_inode);
020ac5b6
AB		 1846 fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
1847 sbi->fsinfo_inode = fsinfo_inode;
1848 insert_inode_hash(fsinfo_inode);
1849
1da177e4
LT		 1850 root_inode = new_inode(sb);
1851 if (!root_inode)
1852 goto out_fail;
1853 root_inode->i_ino = MSDOS_ROOT_INO;
2489dbab 1854 inode_set_iversion(root_inode, 1);
1da177e4 1855 error = fat_read_root(root_inode);
1688f860
AV		 1856 if (error < 0) {
1857 iput(root_inode);
1da177e4 1858 goto out_fail;
1688f860 1859 }
1da177e4
LT		 1860 error = -ENOMEM;
1861 insert_inode_hash(root_inode);
7669e8fb 1862 fat_attach(root_inode, 0);
1688f860 1863 sb->s_root = d_make_root(root_inode);
1da177e4 1864 if (!sb->s_root) {
869f58c0 1865 fat_msg(sb, KERN_ERR, "get root inode failed");
1da177e4
LT		 1866 goto out_fail;
1867 }
1868
f562146a
NJ		 1869 if (sbi->options.discard) {
1870 struct request_queue *q = bdev_get_queue(sb->s_bdev);
1871 if (!blk_queue_discard(q))
1872 fat_msg(sb, KERN_WARNING,
1873 "mounting with \"discard\" option, but "
1874 "the device does not support discard");
1875 }
1876
b88a1058 1877 fat_set_state(sb, 1, 0);
1da177e4
LT		 1878 return 0;
1879
1880out_invalid:
1881 error = -EINVAL;
1882 if (!silent)
869f58c0 1883 fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem");
1da177e4
LT		 1884
1885out_fail:
020ac5b6
AB		 1886 if (fsinfo_inode)
1887 iput(fsinfo_inode);
b522412a
AV		 1888 if (fat_inode)
1889 iput(fat_inode);
1bdb6f91
OH		 1890 unload_nls(sbi->nls_io);
1891 unload_nls(sbi->nls_disk);
35033ab9 1892 fat_reset_iocharset(&sbi->options);
1da177e4
LT		 1893 sb->s_fs_info = NULL;
1894 kfree(sbi);
1895 return error;
1896}
1897
7c709d00 1898EXPORT_SYMBOL_GPL(fat_fill_super);
1da177e4 1899
ae78bf9c
CM		 1900/*
1901 * helper function for fat_flush_inodes. This writes both the inode
1902 * and the file data blocks, waiting for in flight data blocks before
1903 * the start of the call. It does not wait for any io started
1904 * during the call
1905 */
1906static int writeback_inode(struct inode *inode)
1907{
1908
1909 int ret;
14864655
NJ		 1910
1911 /* if we used wait=1, sync_inode_metadata waits for the io for the
1912 * inode to finish. So wait=0 is sent down to sync_inode_metadata
ae78bf9c
CM		 1913 * and filemap_fdatawrite is used for the data blocks
1914 */
14864655 1915 ret = sync_inode_metadata(inode, 0);
ae78bf9c 1916 if (!ret)
14864655 1917 ret = filemap_fdatawrite(inode->i_mapping);
ae78bf9c
CM		 1918 return ret;
1919}
1920
1921/*
1922 * write data and metadata corresponding to i1 and i2. The io is
1923 * started but we do not wait for any of it to finish.
1924 *
1925 * filemap_flush is used for the block device, so if there is a dirty
1926 * page for a block already in flight, we will not wait and start the
1927 * io over again
1928 */
1929int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1930{
1931 int ret = 0;
1932 if (!MSDOS_SB(sb)->options.flush)
1933 return 0;
1934 if (i1)
1935 ret = writeback_inode(i1);
1936 if (!ret && i2)
1937 ret = writeback_inode(i2);
97e860d3 1938 if (!ret) {
ae78bf9c
CM		 1939 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
1940 ret = filemap_flush(mapping);
1941 }
1942 return ret;
1943}
1944EXPORT_SYMBOL_GPL(fat_flush_inodes);
1945
1da177e4
LT		 1946static int __init init_fat_fs(void)
1947{
532a39a3 1948 int err;
1da177e4 1949
532a39a3
PE		 1950 err = fat_cache_init();
1951 if (err)
1952 return err;
1953
1954 err = fat_init_inodecache();
1955 if (err)
1956 goto failed;
1957
1958 return 0;
1959
1960failed:
1961 fat_cache_destroy();
1962 return err;
1da177e4
LT		 1963}
1964
1965static void __exit exit_fat_fs(void)
1966{
1967 fat_cache_destroy();
1968 fat_destroy_inodecache();
1969}
1970
1971module_init(init_fat_fs)
1972module_exit(exit_fat_fs)
1973
1974MODULE_LICENSE("GPL");
Linux 6.x block layer and io_uring tree(s)