1 // SPDX-License-Identifier: GPL-2.0-only
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
11 * Max Cohan: Fixed invalid FSINFO offset when info_sector is 0
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>
28 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET
29 /* if user don't select VFAT, this is undefined. */
30 #define CONFIG_FAT_DEFAULT_IOCHARSET ""
33 #define KB_IN_SECTORS 2
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)
41 * A deserialized copy of the on-disk structure laid out in struct
44 struct fat_bios_param_block
{
58 u32 fat32_root_cluster
;
59 u16 fat32_info_sector
;
64 static int fat_default_codepage
= CONFIG_FAT_DEFAULT_CODEPAGE
;
65 static char fat_default_iocharset
[] = CONFIG_FAT_DEFAULT_IOCHARSET
;
67 static struct fat_floppy_defaults
{
69 unsigned sec_per_clus
;
73 } floppy_defaults
[] = {
75 .nr_sectors
= 160 * KB_IN_SECTORS
,
82 .nr_sectors
= 180 * KB_IN_SECTORS
,
89 .nr_sectors
= 320 * KB_IN_SECTORS
,
96 .nr_sectors
= 360 * KB_IN_SECTORS
,
104 int fat_add_cluster(struct inode
*inode
)
108 err
= fat_alloc_clusters(inode
, &cluster
, 1);
111 /* FIXME: this cluster should be added after data of this
112 * cluster is writed */
113 err
= fat_chain_add(inode
, cluster
, 1);
115 fat_free_clusters(inode
, cluster
);
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
)
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
;
129 err
= fat_bmap(inode
, iblock
, &phys
, &mapped_blocks
, create
, false);
133 map_bh(bh_result
, sb
, phys
);
134 *max_blocks
= min(mapped_blocks
, *max_blocks
);
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
);
146 last_block
= inode
->i_blocks
>> (sb
->s_blocksize_bits
- 9);
147 offset
= (unsigned long)iblock
& (sbi
->sec_per_clus
- 1);
149 * allocate a cluster according to the following.
150 * 1) no more available blocks
151 * 2) not part of fallocate region
153 if (!offset
&& !(iblock
< last_block
)) {
154 /* TODO: multiple cluster allocation would be desirable. */
155 err
= fat_add_cluster(inode
);
159 /* available blocks on this cluster */
160 mapped_blocks
= sbi
->sec_per_clus
- offset
;
162 *max_blocks
= min(mapped_blocks
, *max_blocks
);
163 MSDOS_I(inode
)->mmu_private
+= *max_blocks
<< sb
->s_blocksize_bits
;
165 err
= fat_bmap(inode
, iblock
, &phys
, &mapped_blocks
, create
, false);
170 "invalid FAT chain (i_pos %lld, last_block %llu)",
171 MSDOS_I(inode
)->i_pos
,
172 (unsigned long long)last_block
);
176 BUG_ON(*max_blocks
!= mapped_blocks
);
177 set_buffer_new(bh_result
);
178 map_bh(bh_result
, sb
, phys
);
183 static int fat_get_block(struct inode
*inode
, sector_t iblock
,
184 struct buffer_head
*bh_result
, int create
)
186 struct super_block
*sb
= inode
->i_sb
;
187 unsigned long max_blocks
= bh_result
->b_size
>> inode
->i_blkbits
;
190 err
= __fat_get_block(inode
, iblock
, &max_blocks
, bh_result
, create
);
193 bh_result
->b_size
= max_blocks
<< sb
->s_blocksize_bits
;
197 static int fat_writepage(struct page
*page
, struct writeback_control
*wbc
)
199 return block_write_full_page(page
, fat_get_block
, wbc
);
202 static int fat_writepages(struct address_space
*mapping
,
203 struct writeback_control
*wbc
)
205 return mpage_writepages(mapping
, wbc
, fat_get_block
);
208 static int fat_readpage(struct file
*file
, struct page
*page
)
210 return mpage_readpage(page
, fat_get_block
);
213 static void fat_readahead(struct readahead_control
*rac
)
215 mpage_readahead(rac
, fat_get_block
);
218 static void fat_write_failed(struct address_space
*mapping
, loff_t to
)
220 struct inode
*inode
= mapping
->host
;
222 if (to
> inode
->i_size
) {
223 truncate_pagecache(inode
, inode
->i_size
);
224 fat_truncate_blocks(inode
, inode
->i_size
);
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
)
235 err
= cont_write_begin(file
, mapping
, pos
, len
, flags
,
236 pagep
, fsdata
, fat_get_block
,
237 &MSDOS_I(mapping
->host
)->mmu_private
);
239 fat_write_failed(mapping
, pos
+ len
);
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
)
247 struct inode
*inode
= mapping
->host
;
249 err
= generic_write_end(file
, mapping
, pos
, len
, copied
, pagep
, fsdata
);
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
);
260 static ssize_t
fat_direct_IO(struct kiocb
*iocb
, struct iov_iter
*iter
)
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
;
269 if (iov_iter_rw(iter
) == WRITE
) {
271 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
272 * so we need to update the ->mmu_private to block boundary.
274 * But we must fill the remaining area or hole by nul for
275 * updating ->mmu_private.
277 * Return 0, and fallback to normal buffered write.
279 loff_t size
= offset
+ count
;
280 if (MSDOS_I(inode
)->mmu_private
< size
)
285 * FAT need to use the DIO_LOCKING for avoiding the race
286 * condition of fat_get_block() and ->truncate().
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
);
295 static int fat_get_block_bmap(struct inode
*inode
, sector_t iblock
,
296 struct buffer_head
*bh_result
, int create
)
298 struct super_block
*sb
= inode
->i_sb
;
299 unsigned long max_blocks
= bh_result
->b_size
>> inode
->i_blkbits
;
302 unsigned long mapped_blocks
;
306 err
= fat_bmap(inode
, iblock
, &bmap
, &mapped_blocks
, create
, true);
311 map_bh(bh_result
, sb
, bmap
);
312 max_blocks
= min(mapped_blocks
, max_blocks
);
315 bh_result
->b_size
= max_blocks
<< sb
->s_blocksize_bits
;
320 static sector_t
_fat_bmap(struct address_space
*mapping
, sector_t block
)
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
);
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"
339 int fat_block_truncate_page(struct inode
*inode
, loff_t from
)
341 return block_truncate_page(inode
->i_mapping
, from
, fat_get_block
);
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
,
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
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
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.
379 static void fat_hash_init(struct super_block
*sb
)
381 struct msdos_sb_info
*sbi
= MSDOS_SB(sb
);
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
]);
389 static inline unsigned long fat_hash(loff_t i_pos
)
391 return hash_32(i_pos
, FAT_HASH_BITS
);
394 static void dir_hash_init(struct super_block
*sb
)
396 struct msdos_sb_info
*sbi
= MSDOS_SB(sb
);
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
]);
404 void fat_attach(struct inode
*inode
, loff_t i_pos
)
406 struct msdos_sb_info
*sbi
= MSDOS_SB(inode
->i_sb
);
408 if (inode
->i_ino
!= MSDOS_ROOT_INO
) {
409 struct hlist_head
*head
= sbi
->inode_hashtable
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
);
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.
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
);
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
);
431 EXPORT_SYMBOL_GPL(fat_attach
);
433 void fat_detach(struct inode
*inode
)
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
);
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
);
447 EXPORT_SYMBOL_GPL(fat_detach
);
449 struct inode
*fat_iget(struct super_block
*sb
, loff_t i_pos
)
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
;
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
)
461 inode
= igrab(&i
->vfs_inode
);
465 spin_unlock(&sbi
->inode_hash_lock
);
469 static int is_exec(unsigned char *extension
)
471 unsigned char exe_extensions
[] = "EXECOMBAT", *walk
;
473 for (walk
= exe_extensions
; *walk
; walk
+= 3)
474 if (!strncmp(extension
, walk
, 3))
479 static int fat_calc_dir_size(struct inode
*inode
)
481 struct msdos_sb_info
*sbi
= MSDOS_SB(inode
->i_sb
);
482 int ret
, fclus
, dclus
;
485 if (MSDOS_I(inode
)->i_start
== 0)
488 ret
= fat_get_cluster(inode
, FAT_ENT_EOF
, &fclus
, &dclus
);
491 inode
->i_size
= (fclus
+ 1) << sbi
->cluster_bits
;
496 static int fat_validate_dir(struct inode
*dir
)
498 struct super_block
*sb
= dir
->i_sb
;
500 if (dir
->i_nlink
< 2) {
501 /* Directory should have "."/".." entries at least. */
502 fat_fs_error(sb
, "corrupted directory (invalid entries)");
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)");
514 /* doesn't deal with root inode */
515 int fat_fill_inode(struct inode
*inode
, struct msdos_dir_entry
*de
)
517 struct msdos_sb_info
*sbi
= MSDOS_SB(inode
->i_sb
);
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();
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
;
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
);
537 MSDOS_I(inode
)->mmu_private
= inode
->i_size
;
539 set_nlink(inode
, fat_subdirs(inode
));
541 error
= fat_validate_dir(inode
);
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
);
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
;
558 if (de
->attr
& ATTR_SYS
) {
559 if (sbi
->options
.sys_immutable
)
560 inode
->i_flags
|= S_IMMUTABLE
;
562 fat_save_attrs(inode
, de
->attr
);
564 inode
->i_blocks
= ((inode
->i_size
+ (sbi
->cluster_size
- 1))
565 & ~((loff_t
)sbi
->cluster_size
- 1)) >> 9;
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);
573 fat_truncate_time(inode
, &inode
->i_mtime
, S_ATIME
|S_CTIME
);
578 static inline void fat_lock_build_inode(struct msdos_sb_info
*sbi
)
580 if (sbi
->options
.nfs
== FAT_NFS_NOSTALE_RO
)
581 mutex_lock(&sbi
->nfs_build_inode_lock
);
584 static inline void fat_unlock_build_inode(struct msdos_sb_info
*sbi
)
586 if (sbi
->options
.nfs
== FAT_NFS_NOSTALE_RO
)
587 mutex_unlock(&sbi
->nfs_build_inode_lock
);
590 struct inode
*fat_build_inode(struct super_block
*sb
,
591 struct msdos_dir_entry
*de
, loff_t i_pos
)
596 fat_lock_build_inode(MSDOS_SB(sb
));
597 inode
= fat_iget(sb
, i_pos
);
600 inode
= new_inode(sb
);
602 inode
= ERR_PTR(-ENOMEM
);
605 inode
->i_ino
= iunique(sb
, MSDOS_ROOT_INO
);
606 inode_set_iversion(inode
, 1);
607 err
= fat_fill_inode(inode
, de
);
610 inode
= ERR_PTR(err
);
613 fat_attach(inode
, i_pos
);
614 insert_inode_hash(inode
);
616 fat_unlock_build_inode(MSDOS_SB(sb
));
620 EXPORT_SYMBOL_GPL(fat_build_inode
);
622 static int __fat_write_inode(struct inode
*inode
, int wait
);
624 static void fat_free_eofblocks(struct inode
*inode
)
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
)) {
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.
639 err
= __fat_write_inode(inode
, inode_needs_sync(inode
));
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");
650 static void fat_evict_inode(struct inode
*inode
)
652 truncate_inode_pages_final(&inode
->i_data
);
653 if (!inode
->i_nlink
) {
655 fat_truncate_blocks(inode
, 0);
657 fat_free_eofblocks(inode
);
659 invalidate_inode_buffers(inode
);
661 fat_cache_inval_inode(inode
);
665 static void fat_set_state(struct super_block
*sb
,
666 unsigned int set
, unsigned int force
)
668 struct buffer_head
*bh
;
669 struct fat_boot_sector
*b
;
670 struct msdos_sb_info
*sbi
= MSDOS_SB(sb
);
672 /* do not change any thing if mounted read only */
673 if (sb_rdonly(sb
) && !force
)
676 /* do not change state if fs was dirty */
678 /* warn only on set (mount). */
680 fat_msg(sb
, KERN_WARNING
, "Volume was not properly "
681 "unmounted. Some data may be corrupt. "
686 bh
= sb_bread(sb
, 0);
688 fat_msg(sb
, KERN_ERR
, "unable to read boot sector "
689 "to mark fs as dirty");
693 b
= (struct fat_boot_sector
*) bh
->b_data
;
697 b
->fat32
.state
|= FAT_STATE_DIRTY
;
699 b
->fat32
.state
&= ~FAT_STATE_DIRTY
;
700 } else /* fat 16 and 12 */ {
702 b
->fat16
.state
|= FAT_STATE_DIRTY
;
704 b
->fat16
.state
&= ~FAT_STATE_DIRTY
;
707 mark_buffer_dirty(bh
);
708 sync_dirty_buffer(bh
);
712 static void fat_reset_iocharset(struct fat_mount_options
*opts
)
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
;
721 static void delayed_free(struct rcu_head
*p
)
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
);
730 static void fat_put_super(struct super_block
*sb
)
732 struct msdos_sb_info
*sbi
= MSDOS_SB(sb
);
734 fat_set_state(sb
, 0, 0);
736 iput(sbi
->fsinfo_inode
);
737 iput(sbi
->fat_inode
);
739 call_rcu(&sbi
->rcu
, delayed_free
);
742 static struct kmem_cache
*fat_inode_cachep
;
744 static struct inode
*fat_alloc_inode(struct super_block
*sb
)
746 struct msdos_inode_info
*ei
;
747 ei
= kmem_cache_alloc(fat_inode_cachep
, GFP_NOFS
);
751 init_rwsem(&ei
->truncate_lock
);
752 /* Zeroing to allow iput() even if partial initialized inode. */
759 return &ei
->vfs_inode
;
762 static void fat_free_inode(struct inode
*inode
)
764 kmem_cache_free(fat_inode_cachep
, MSDOS_I(inode
));
767 static void init_once(void *foo
)
769 struct msdos_inode_info
*ei
= (struct msdos_inode_info
*)foo
;
771 spin_lock_init(&ei
->cache_lru_lock
);
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
);
780 static int __init
fat_init_inodecache(void)
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
),
787 if (fat_inode_cachep
== NULL
)
792 static void __exit
fat_destroy_inodecache(void)
795 * Make sure all delayed rcu free inodes are flushed before we
799 kmem_cache_destroy(fat_inode_cachep
);
802 static int fat_remount(struct super_block
*sb
, int *flags
, char *data
)
805 struct msdos_sb_info
*sbi
= MSDOS_SB(sb
);
806 *flags
|= SB_NODIRATIME
| (sbi
->options
.isvfat
? 0 : SB_NOATIME
);
810 /* make sure we update state on remount. */
811 new_rdonly
= *flags
& SB_RDONLY
;
812 if (new_rdonly
!= sb_rdonly(sb
)) {
814 fat_set_state(sb
, 0, 0);
816 fat_set_state(sb
, 1, 1);
821 static int fat_statfs(struct dentry
*dentry
, struct kstatfs
*buf
)
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
);
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
);
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
);
841 (sbi
->options
.isvfat
? FAT_LFN_LEN
: 12) * NLS_MAX_CHARSET_SIZE
;
846 static int __fat_write_inode(struct inode
*inode
, int wait
)
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
;
856 if (inode
->i_ino
== MSDOS_ROOT_INO
)
860 i_pos
= fat_i_pos_read(sbi
, inode
);
864 fat_get_blknr_offset(sbi
, i_pos
, &blocknr
, &offset
);
865 bh
= sb_bread(sb
, blocknr
);
867 fat_msg(sb
, KERN_ERR
, "unable to read inode block "
868 "for updating (i_pos %lld)", i_pos
);
871 spin_lock(&sbi
->inode_hash_lock
);
872 if (i_pos
!= MSDOS_I(inode
)->i_pos
) {
873 spin_unlock(&sbi
->inode_hash_lock
);
878 raw_entry
= &((struct msdos_dir_entry
*) (bh
->b_data
))[offset
];
879 if (S_ISDIR(inode
->i_mode
))
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
) {
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
);
894 spin_unlock(&sbi
->inode_hash_lock
);
895 mark_buffer_dirty(bh
);
898 err
= sync_dirty_buffer(bh
);
903 static int fat_write_inode(struct inode
*inode
, struct writeback_control
*wbc
)
907 if (inode
->i_ino
== MSDOS_FSINFO_INO
) {
908 struct super_block
*sb
= inode
->i_sb
;
910 mutex_lock(&MSDOS_SB(sb
)->s_lock
);
911 err
= fat_clusters_flush(sb
);
912 mutex_unlock(&MSDOS_SB(sb
)->s_lock
);
914 err
= __fat_write_inode(inode
, wbc
->sync_mode
== WB_SYNC_ALL
);
919 int fat_sync_inode(struct inode
*inode
)
921 return __fat_write_inode(inode
, 1);
924 EXPORT_SYMBOL_GPL(fat_sync_inode
);
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
,
936 .show_options
= fat_show_options
,
939 static int fat_show_options(struct seq_file
*m
, struct dentry
*root
)
941 struct msdos_sb_info
*sbi
= MSDOS_SB(root
->d_sb
);
942 struct fat_mount_options
*opts
= &sbi
->options
;
943 int isvfat
= opts
->isvfat
;
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
);
956 /* strip "cp" prefix from displayed option */
957 seq_printf(m
, ",codepage=%s", &sbi
->nls_disk
->charset
[2]);
960 seq_printf(m
, ",iocharset=%s", sbi
->nls_io
->charset
);
962 switch (opts
->shortname
) {
963 case VFAT_SFN_DISPLAY_WIN95
| VFAT_SFN_CREATE_WIN95
:
964 seq_puts(m
, ",shortname=win95");
966 case VFAT_SFN_DISPLAY_WINNT
| VFAT_SFN_CREATE_WINNT
:
967 seq_puts(m
, ",shortname=winnt");
969 case VFAT_SFN_DISPLAY_WINNT
| VFAT_SFN_CREATE_WIN95
:
970 seq_puts(m
, ",shortname=mixed");
972 case VFAT_SFN_DISPLAY_LOWER
| VFAT_SFN_CREATE_WIN95
:
973 seq_puts(m
, ",shortname=lower");
976 seq_puts(m
, ",shortname=unknown");
980 if (opts
->name_check
!= 'n')
981 seq_printf(m
, ",check=%c", opts
->name_check
);
983 seq_puts(m
, ",usefree");
985 seq_puts(m
, ",quiet");
987 seq_puts(m
, ",showexec");
988 if (opts
->sys_immutable
)
989 seq_puts(m
, ",sys_immutable");
992 seq_puts(m
, ",dotsOK=yes");
994 seq_puts(m
, ",nocase");
997 seq_puts(m
, ",utf8");
998 if (opts
->unicode_xlate
)
999 seq_puts(m
, ",uni_xlate");
1001 seq_puts(m
, ",nonumtail");
1003 seq_puts(m
, ",rodir");
1006 seq_puts(m
, ",flush");
1008 if (opts
->time_offset
)
1009 seq_printf(m
, ",time_offset=%d", opts
->time_offset
);
1011 seq_puts(m
, ",tz=UTC");
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");
1018 seq_puts(m
, ",errors=remount-ro");
1019 if (opts
->nfs
== FAT_NFS_NOSTALE_RO
)
1020 seq_puts(m
, ",nfs=nostale_ro");
1022 seq_puts(m
, ",nfs=stale_rw");
1024 seq_puts(m
, ",discard");
1025 if (opts
->dos1xfloppy
)
1026 seq_puts(m
, ",dos1xfloppy");
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
,
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"},
1088 static const match_table_t msdos_tokens
= {
1089 {Opt_nodots
, "nodots"},
1090 {Opt_nodots
, "dotsOK=no"},
1092 {Opt_dots
, "dotsOK=yes"},
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"},
1126 static int parse_options(struct super_block
*sb
, char *options
, int is_vfat
,
1127 int silent
, int *debug
, struct fat_mount_options
*opts
)
1130 substring_t args
[MAX_OPT_ARGS
];
1134 opts
->isvfat
= is_vfat
;
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
);
1143 opts
->shortname
= VFAT_SFN_DISPLAY_WINNT
|VFAT_SFN_CREATE_WIN95
;
1146 opts
->shortname
= 0;
1149 opts
->name_check
= 'n';
1150 opts
->quiet
= opts
->showexec
= opts
->sys_immutable
= opts
->dotsOK
= 0;
1151 opts
->unicode_xlate
= 0;
1153 opts
->usefree
= opts
->nocase
= 0;
1156 opts
->errors
= FAT_ERRORS_RO
;
1159 opts
->utf8
= IS_ENABLED(CONFIG_FAT_DEFAULT_UTF8
) && is_vfat
;
1164 while ((p
= strsep(&options
, ",")) != NULL
) {
1169 token
= match_token(p
, fat_tokens
, args
);
1170 if (token
== Opt_err
) {
1172 token
= match_token(p
, vfat_tokens
, args
);
1174 token
= match_token(p
, msdos_tokens
, args
);
1178 opts
->name_check
= 's';
1181 opts
->name_check
= 'r';
1184 opts
->name_check
= 'n';
1193 /* for backward compatibility */
1194 opts
->shortname
= VFAT_SFN_DISPLAY_WIN95
1195 | VFAT_SFN_CREATE_WIN95
;
1208 opts
->sys_immutable
= 1;
1211 if (match_int(&args
[0], &option
))
1213 opts
->fs_uid
= make_kuid(current_user_ns(), option
);
1214 if (!uid_valid(opts
->fs_uid
))
1218 if (match_int(&args
[0], &option
))
1220 opts
->fs_gid
= make_kgid(current_user_ns(), option
);
1221 if (!gid_valid(opts
->fs_gid
))
1225 if (match_octal(&args
[0], &option
))
1227 opts
->fs_fmask
= opts
->fs_dmask
= option
;
1230 if (match_octal(&args
[0], &option
))
1232 opts
->fs_dmask
= option
;
1235 if (match_octal(&args
[0], &option
))
1237 opts
->fs_fmask
= option
;
1239 case Opt_allow_utime
:
1240 if (match_octal(&args
[0], &option
))
1242 opts
->allow_utime
= option
& (S_IWGRP
| S_IWOTH
);
1245 if (match_int(&args
[0], &option
))
1247 opts
->codepage
= option
;
1252 case Opt_time_offset
:
1253 if (match_int(&args
[0], &option
))
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.
1260 if (option
< -24 * 60 || option
> 24 * 60)
1263 opts
->time_offset
= option
;
1267 opts
->time_offset
= 0;
1270 opts
->errors
= FAT_ERRORS_CONT
;
1273 opts
->errors
= FAT_ERRORS_PANIC
;
1276 opts
->errors
= FAT_ERRORS_RO
;
1278 case Opt_nfs_stale_rw
:
1279 opts
->nfs
= FAT_NFS_STALE_RW
;
1281 case Opt_nfs_nostale_ro
:
1282 opts
->nfs
= FAT_NFS_NOSTALE_RO
;
1284 case Opt_dos1xfloppy
:
1285 opts
->dos1xfloppy
= 1;
1288 /* msdos specific */
1298 fat_reset_iocharset(opts
);
1299 iocharset
= match_strdup(&args
[0]);
1302 opts
->iocharset
= iocharset
;
1304 case Opt_shortname_lower
:
1305 opts
->shortname
= VFAT_SFN_DISPLAY_LOWER
1306 | VFAT_SFN_CREATE_WIN95
;
1308 case Opt_shortname_win95
:
1309 opts
->shortname
= VFAT_SFN_DISPLAY_WIN95
1310 | VFAT_SFN_CREATE_WIN95
;
1312 case Opt_shortname_winnt
:
1313 opts
->shortname
= VFAT_SFN_DISPLAY_WINNT
1314 | VFAT_SFN_CREATE_WINNT
;
1316 case Opt_shortname_mixed
:
1317 opts
->shortname
= VFAT_SFN_DISPLAY_WINNT
1318 | VFAT_SFN_CREATE_WIN95
;
1320 case Opt_utf8_no
: /* 0 or no or false */
1323 case Opt_utf8_yes
: /* empty or 1 or yes or true */
1326 case Opt_uni_xl_no
: /* 0 or no or false */
1327 opts
->unicode_xlate
= 0;
1329 case Opt_uni_xl_yes
: /* empty or 1 or yes or true */
1330 opts
->unicode_xlate
= 1;
1332 case Opt_nonumtail_no
: /* 0 or no or false */
1333 opts
->numtail
= 1; /* negated option */
1335 case Opt_nonumtail_yes
: /* empty or 1 or yes or true */
1336 opts
->numtail
= 0; /* negated option */
1345 /* obsolete mount options */
1347 fat_msg(sb
, KERN_INFO
, "\"%s\" option is obsolete, "
1348 "not supported now", p
);
1350 /* unknown option */
1353 fat_msg(sb
, KERN_ERR
,
1354 "Unrecognized mount option \"%s\" "
1355 "or missing value", p
);
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 "
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
)
1374 if (opts
->nfs
== FAT_NFS_NOSTALE_RO
) {
1375 sb
->s_flags
|= SB_RDONLY
;
1376 sb
->s_export_op
= &fat_export_ops_nostale
;
1382 static int fat_read_root(struct inode
*inode
)
1384 struct msdos_sb_info
*sbi
= MSDOS_SB(inode
->i_sb
);
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
);
1401 MSDOS_I(inode
)->i_start
= 0;
1402 inode
->i_size
= sbi
->dir_entries
* sizeof(struct msdos_dir_entry
);
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
;
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);
1417 static unsigned long calc_fat_clusters(struct super_block
*sb
)
1419 struct msdos_sb_info
*sbi
= MSDOS_SB(sb
);
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
;
1427 return sbi
->fat_length
* sb
->s_blocksize
* 8 / sbi
->fat_bits
;
1430 static bool fat_bpb_is_zero(struct fat_boot_sector
*b
)
1432 if (get_unaligned_le16(&b
->sector_size
))
1434 if (b
->sec_per_clus
)
1440 if (get_unaligned_le16(&b
->dir_entries
))
1442 if (get_unaligned_le16(&b
->sectors
))
1455 static int fat_read_bpb(struct super_block
*sb
, struct fat_boot_sector
*b
,
1456 int silent
, struct fat_bios_param_block
*bpb
)
1458 int error
= -EINVAL
;
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
);
1471 bpb
->fat16_state
= b
->fat16
.state
;
1472 bpb
->fat16_vol_id
= get_unaligned_le32(b
->fat16
.vol_id
);
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
);
1480 /* Validate this looks like a FAT filesystem BPB */
1481 if (!bpb
->fat_reserved
) {
1483 fat_msg(sb
, KERN_ERR
,
1484 "bogus number of reserved sectors");
1487 if (!bpb
->fat_fats
) {
1489 fat_msg(sb
, KERN_ERR
, "bogus number of FAT structure");
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.
1498 if (!fat_valid_media(b
->media
)) {
1500 fat_msg(sb
, KERN_ERR
, "invalid media value (0x%02x)",
1501 (unsigned)b
->media
);
1505 if (!is_power_of_2(bpb
->fat_sector_size
)
1506 || (bpb
->fat_sector_size
< 512)
1507 || (bpb
->fat_sector_size
> 4096)) {
1509 fat_msg(sb
, KERN_ERR
, "bogus logical sector size %u",
1510 (unsigned)bpb
->fat_sector_size
);
1514 if (!is_power_of_2(bpb
->fat_sec_per_clus
)) {
1516 fat_msg(sb
, KERN_ERR
, "bogus sectors per cluster %u",
1517 (unsigned)bpb
->fat_sec_per_clus
);
1521 if (bpb
->fat_fat_length
== 0 && bpb
->fat32_length
== 0) {
1523 fat_msg(sb
, KERN_ERR
, "bogus number of FAT sectors");
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
)
1537 static const char *notdos1x
= "This doesn't look like a DOS 1.x volume";
1539 struct fat_floppy_defaults
*fdefaults
= NULL
;
1540 int error
= -EINVAL
;
1544 bd_sects
= i_size_read(sb
->s_bdev
->bd_inode
) / SECTOR_SIZE
;
1546 /* 16-bit DOS 1.x reliably wrote bootstrap short-jmp code */
1547 if (b
->ignored
[0] != 0xeb || b
->ignored
[2] != 0x90) {
1549 fat_msg(sb
, KERN_ERR
,
1550 "%s; no bootstrapping code", notdos1x
);
1555 * If any value in this region is non-zero, it isn't archaic
1558 if (!fat_bpb_is_zero(b
)) {
1560 fat_msg(sb
, KERN_ERR
,
1561 "%s; DOS 2.x BPB is non-zero", notdos1x
);
1565 for (i
= 0; i
< ARRAY_SIZE(floppy_defaults
); i
++) {
1566 if (floppy_defaults
[i
].nr_sectors
== bd_sects
) {
1567 fdefaults
= &floppy_defaults
[i
];
1572 if (fdefaults
== NULL
) {
1574 fat_msg(sb
, KERN_WARNING
,
1575 "This looks like a DOS 1.x volume, but isn't a recognized floppy size (%llu sectors)",
1581 fat_msg(sb
, KERN_INFO
,
1582 "This looks like a DOS 1.x volume; assuming default BPB values");
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;
1589 bpb
->fat_dir_entries
= fdefaults
->dir_entries
;
1590 bpb
->fat_sectors
= fdefaults
->nr_sectors
;
1591 bpb
->fat_fat_length
= fdefaults
->fat_length
;
1600 * Read the super block of an MS-DOS FS.
1602 int fat_fill_super(struct super_block
*sb
, void *data
, int silent
, int isvfat
,
1603 void (*setup
)(struct super_block
*))
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
;
1615 struct timespec64 ts
;
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!
1623 sbi
= kzalloc(sizeof(struct msdos_sb_info
), GFP_KERNEL
);
1626 sb
->s_fs_info
= sbi
;
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
;
1633 * fat timestamps are complex and truncated by fat itself, so
1634 * we set 1 here to be fast
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
);
1641 error
= parse_options(sb
, data
, isvfat
, silent
, &debug
, &sbi
->options
);
1645 setup(sb
); /* flavour-specific stuff that needs options */
1648 sb_min_blocksize(sb
, 512);
1649 bh
= sb_bread(sb
, 0);
1651 fat_msg(sb
, KERN_ERR
, "unable to read boot sector");
1655 error
= fat_read_bpb(sb
, (struct fat_boot_sector
*)bh
->b_data
, silent
,
1657 if (error
== -EINVAL
&& sbi
->options
.dos1xfloppy
)
1658 error
= fat_read_static_bpb(sb
,
1659 (struct fat_boot_sector
*)bh
->b_data
, silent
, &bpb
);
1662 if (error
== -EINVAL
)
1667 logical_sector_size
= bpb
.fat_sector_size
;
1668 sbi
->sec_per_clus
= bpb
.fat_sec_per_clus
;
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
);
1677 if (logical_sector_size
> sb
->s_blocksize
) {
1678 struct buffer_head
*bh_resize
;
1680 if (!sb_set_blocksize(sb
, logical_sector_size
)) {
1681 fat_msg(sb
, KERN_ERR
, "unable to set blocksize %u",
1682 logical_sector_size
);
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)",
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
;
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
;
1716 if (!sbi
->fat_length
&& bpb
.fat32_length
) {
1717 struct fat_boot_fsinfo
*fsinfo
;
1718 struct buffer_head
*fsinfo_bh
;
1722 sbi
->fat_length
= bpb
.fat32_length
;
1723 sbi
->root_cluster
= bpb
.fat32_root_cluster
;
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;
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
);
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
);
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
);
1754 /* interpret volume ID as a little endian 32 bit integer */
1756 sbi
->vol_id
= bpb
.fat32_vol_id
;
1757 else /* fat 16 or 12 */
1758 sbi
->vol_id
= bpb
.fat16_vol_id
;
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;
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)) {
1767 fat_msg(sb
, KERN_ERR
, "bogus number of directory entries"
1768 " (%u)", sbi
->dir_entries
);
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
;
1779 total_clusters
= (total_sectors
- sbi
->data_start
) / sbi
->sec_per_clus
;
1782 sbi
->fat_bits
= (total_clusters
> MAX_FAT12
) ? 16 : 12;
1784 /* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
1786 sbi
->dirty
= bpb
.fat32_state
& FAT_STATE_DIRTY
;
1787 else /* fat 16 or 12 */
1788 sbi
->dirty
= bpb
.fat16_state
& FAT_STATE_DIRTY
;
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
)) {
1795 fat_msg(sb
, KERN_ERR
, "count of clusters too big (%u)",
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
;
1809 /* set up enough so that it can read an inode */
1812 fat_ent_access_init(sb
);
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.
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
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
);
1834 /* FIXME: utf8 is using iocharset for upper/lower conversion */
1835 if (sbi
->options
.isvfat
) {
1836 sbi
->nls_io
= load_nls(sbi
->options
.iocharset
);
1838 fat_msg(sb
, KERN_ERR
, "IO charset %s not found",
1839 sbi
->options
.iocharset
);
1845 fat_inode
= new_inode(sb
);
1848 sbi
->fat_inode
= fat_inode
;
1850 fsinfo_inode
= new_inode(sb
);
1853 fsinfo_inode
->i_ino
= MSDOS_FSINFO_INO
;
1854 sbi
->fsinfo_inode
= fsinfo_inode
;
1855 insert_inode_hash(fsinfo_inode
);
1857 root_inode
= new_inode(sb
);
1860 root_inode
->i_ino
= MSDOS_ROOT_INO
;
1861 inode_set_iversion(root_inode
, 1);
1862 error
= fat_read_root(root_inode
);
1868 insert_inode_hash(root_inode
);
1869 fat_attach(root_inode
, 0);
1870 sb
->s_root
= d_make_root(root_inode
);
1872 fat_msg(sb
, KERN_ERR
, "get root inode failed");
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");
1884 fat_set_state(sb
, 1, 0);
1890 fat_msg(sb
, KERN_INFO
, "Can't find a valid FAT filesystem");
1897 unload_nls(sbi
->nls_io
);
1898 unload_nls(sbi
->nls_disk
);
1899 fat_reset_iocharset(&sbi
->options
);
1900 sb
->s_fs_info
= NULL
;
1905 EXPORT_SYMBOL_GPL(fat_fill_super
);
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
1913 static int writeback_inode(struct inode
*inode
)
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
1922 ret
= sync_inode_metadata(inode
, 0);
1924 ret
= filemap_fdatawrite(inode
->i_mapping
);
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.
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
1936 int fat_flush_inodes(struct super_block
*sb
, struct inode
*i1
, struct inode
*i2
)
1939 if (!MSDOS_SB(sb
)->options
.flush
)
1942 ret
= writeback_inode(i1
);
1944 ret
= writeback_inode(i2
);
1946 struct address_space
*mapping
= sb
->s_bdev
->bd_inode
->i_mapping
;
1947 ret
= filemap_flush(mapping
);
1951 EXPORT_SYMBOL_GPL(fat_flush_inodes
);
1953 static int __init
init_fat_fs(void)
1957 err
= fat_cache_init();
1961 err
= fat_init_inodecache();
1968 fat_cache_destroy();
1972 static void __exit
exit_fat_fs(void)
1974 fat_cache_destroy();
1975 fat_destroy_inodecache();
1978 module_init(init_fat_fs
)
1979 module_exit(exit_fat_fs
)
1981 MODULE_LICENSE("GPL");