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
10 * Max Cohan: Fixed invalid FSINFO offset when info_sector is 0
13 #include <linux/module.h>
14 #include <linux/pagemap.h>
15 #include <linux/mpage.h>
16 #include <linux/vfs.h>
17 #include <linux/seq_file.h>
18 #include <linux/parser.h>
19 #include <linux/uio.h>
20 #include <linux/blkdev.h>
21 #include <linux/backing-dev.h>
22 #include <asm/unaligned.h>
25 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET
26 /* if user don't select VFAT, this is undefined. */
27 #define CONFIG_FAT_DEFAULT_IOCHARSET ""
30 #define KB_IN_SECTORS 2
33 * A deserialized copy of the on-disk structure laid out in struct
36 struct fat_bios_param_block {
50 u32 fat32_root_cluster;
51 u16 fat32_info_sector;
56 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
57 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
59 static struct fat_floppy_defaults {
61 unsigned sec_per_clus;
65 } floppy_defaults[] = {
67 .nr_sectors = 160 * KB_IN_SECTORS,
74 .nr_sectors = 180 * KB_IN_SECTORS,
81 .nr_sectors = 320 * KB_IN_SECTORS,
88 .nr_sectors = 360 * KB_IN_SECTORS,
96 static int fat_add_cluster(struct inode *inode)
100 err = fat_alloc_clusters(inode, &cluster, 1);
103 /* FIXME: this cluster should be added after data of this
104 * cluster is writed */
105 err = fat_chain_add(inode, cluster, 1);
107 fat_free_clusters(inode, cluster);
111 static inline int __fat_get_block(struct inode *inode, sector_t iblock,
112 unsigned long *max_blocks,
113 struct buffer_head *bh_result, int create)
115 struct super_block *sb = inode->i_sb;
116 struct msdos_sb_info *sbi = MSDOS_SB(sb);
117 unsigned long mapped_blocks;
121 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
125 map_bh(bh_result, sb, phys);
126 *max_blocks = min(mapped_blocks, *max_blocks);
132 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
133 fat_fs_error(sb, "corrupted file size (i_pos %lld, %lld)",
134 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
138 offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
140 /* TODO: multiple cluster allocation would be desirable. */
141 err = fat_add_cluster(inode);
145 /* available blocks on this cluster */
146 mapped_blocks = sbi->sec_per_clus - offset;
148 *max_blocks = min(mapped_blocks, *max_blocks);
149 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
151 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
156 BUG_ON(*max_blocks != mapped_blocks);
157 set_buffer_new(bh_result);
158 map_bh(bh_result, sb, phys);
163 static int fat_get_block(struct inode *inode, sector_t iblock,
164 struct buffer_head *bh_result, int create)
166 struct super_block *sb = inode->i_sb;
167 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
170 err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create);
173 bh_result->b_size = max_blocks << sb->s_blocksize_bits;
177 static int fat_writepage(struct page *page, struct writeback_control *wbc)
179 return block_write_full_page(page, fat_get_block, wbc);
182 static int fat_writepages(struct address_space *mapping,
183 struct writeback_control *wbc)
185 return mpage_writepages(mapping, wbc, fat_get_block);
188 static int fat_readpage(struct file *file, struct page *page)
190 return mpage_readpage(page, fat_get_block);
193 static int fat_readpages(struct file *file, struct address_space *mapping,
194 struct list_head *pages, unsigned nr_pages)
196 return mpage_readpages(mapping, pages, nr_pages, fat_get_block);
199 static void fat_write_failed(struct address_space *mapping, loff_t to)
201 struct inode *inode = mapping->host;
203 if (to > inode->i_size) {
204 truncate_pagecache(inode, inode->i_size);
205 fat_truncate_blocks(inode, inode->i_size);
209 static int fat_write_begin(struct file *file, struct address_space *mapping,
210 loff_t pos, unsigned len, unsigned flags,
211 struct page **pagep, void **fsdata)
216 err = cont_write_begin(file, mapping, pos, len, flags,
217 pagep, fsdata, fat_get_block,
218 &MSDOS_I(mapping->host)->mmu_private);
220 fat_write_failed(mapping, pos + len);
224 static int fat_write_end(struct file *file, struct address_space *mapping,
225 loff_t pos, unsigned len, unsigned copied,
226 struct page *pagep, void *fsdata)
228 struct inode *inode = mapping->host;
230 err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
232 fat_write_failed(mapping, pos + len);
233 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
234 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
235 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
236 mark_inode_dirty(inode);
241 static ssize_t fat_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
244 struct file *file = iocb->ki_filp;
245 struct address_space *mapping = file->f_mapping;
246 struct inode *inode = mapping->host;
247 size_t count = iov_iter_count(iter);
250 if (iov_iter_rw(iter) == WRITE) {
252 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
253 * so we need to update the ->mmu_private to block boundary.
255 * But we must fill the remaining area or hole by nul for
256 * updating ->mmu_private.
258 * Return 0, and fallback to normal buffered write.
260 loff_t size = offset + count;
261 if (MSDOS_I(inode)->mmu_private < size)
266 * FAT need to use the DIO_LOCKING for avoiding the race
267 * condition of fat_get_block() and ->truncate().
269 ret = blockdev_direct_IO(iocb, inode, iter, offset, fat_get_block);
270 if (ret < 0 && iov_iter_rw(iter) == WRITE)
271 fat_write_failed(mapping, offset + count);
276 static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
280 /* fat_get_cluster() assumes the requested blocknr isn't truncated. */
281 down_read(&MSDOS_I(mapping->host)->truncate_lock);
282 blocknr = generic_block_bmap(mapping, block, fat_get_block);
283 up_read(&MSDOS_I(mapping->host)->truncate_lock);
289 * fat_block_truncate_page() zeroes out a mapping from file offset `from'
290 * up to the end of the block which corresponds to `from'.
291 * This is required during truncate to physically zeroout the tail end
292 * of that block so it doesn't yield old data if the file is later grown.
293 * Also, avoid causing failure from fsx for cases of "data past EOF"
295 int fat_block_truncate_page(struct inode *inode, loff_t from)
297 return block_truncate_page(inode->i_mapping, from, fat_get_block);
300 static const struct address_space_operations fat_aops = {
301 .readpage = fat_readpage,
302 .readpages = fat_readpages,
303 .writepage = fat_writepage,
304 .writepages = fat_writepages,
305 .write_begin = fat_write_begin,
306 .write_end = fat_write_end,
307 .direct_IO = fat_direct_IO,
312 * New FAT inode stuff. We do the following:
313 * a) i_ino is constant and has nothing with on-disk location.
314 * b) FAT manages its own cache of directory entries.
315 * c) *This* cache is indexed by on-disk location.
316 * d) inode has an associated directory entry, all right, but
317 * it may be unhashed.
318 * e) currently entries are stored within struct inode. That should
320 * f) we deal with races in the following way:
321 * 1. readdir() and lookup() do FAT-dir-cache lookup.
322 * 2. rename() unhashes the F-d-c entry and rehashes it in
324 * 3. unlink() and rmdir() unhash F-d-c entry.
325 * 4. fat_write_inode() checks whether the thing is unhashed.
326 * If it is we silently return. If it isn't we do bread(),
327 * check if the location is still valid and retry if it
328 * isn't. Otherwise we do changes.
329 * 5. Spinlock is used to protect hash/unhash/location check/lookup
330 * 6. fat_evict_inode() unhashes the F-d-c entry.
331 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry
332 * and consider negative result as cache miss.
335 static void fat_hash_init(struct super_block *sb)
337 struct msdos_sb_info *sbi = MSDOS_SB(sb);
340 spin_lock_init(&sbi->inode_hash_lock);
341 for (i = 0; i < FAT_HASH_SIZE; i++)
342 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
345 static inline unsigned long fat_hash(loff_t i_pos)
347 return hash_32(i_pos, FAT_HASH_BITS);
350 static void dir_hash_init(struct super_block *sb)
352 struct msdos_sb_info *sbi = MSDOS_SB(sb);
355 spin_lock_init(&sbi->dir_hash_lock);
356 for (i = 0; i < FAT_HASH_SIZE; i++)
357 INIT_HLIST_HEAD(&sbi->dir_hashtable[i]);
360 void fat_attach(struct inode *inode, loff_t i_pos)
362 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
364 if (inode->i_ino != MSDOS_ROOT_INO) {
365 struct hlist_head *head = sbi->inode_hashtable
368 spin_lock(&sbi->inode_hash_lock);
369 MSDOS_I(inode)->i_pos = i_pos;
370 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
371 spin_unlock(&sbi->inode_hash_lock);
374 /* If NFS support is enabled, cache the mapping of start cluster
375 * to directory inode. This is used during reconnection of
376 * dentries to the filesystem root.
378 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
379 struct hlist_head *d_head = sbi->dir_hashtable;
380 d_head += fat_dir_hash(MSDOS_I(inode)->i_logstart);
382 spin_lock(&sbi->dir_hash_lock);
383 hlist_add_head(&MSDOS_I(inode)->i_dir_hash, d_head);
384 spin_unlock(&sbi->dir_hash_lock);
387 EXPORT_SYMBOL_GPL(fat_attach);
389 void fat_detach(struct inode *inode)
391 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
392 spin_lock(&sbi->inode_hash_lock);
393 MSDOS_I(inode)->i_pos = 0;
394 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
395 spin_unlock(&sbi->inode_hash_lock);
397 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
398 spin_lock(&sbi->dir_hash_lock);
399 hlist_del_init(&MSDOS_I(inode)->i_dir_hash);
400 spin_unlock(&sbi->dir_hash_lock);
403 EXPORT_SYMBOL_GPL(fat_detach);
405 struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
407 struct msdos_sb_info *sbi = MSDOS_SB(sb);
408 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
409 struct msdos_inode_info *i;
410 struct inode *inode = NULL;
412 spin_lock(&sbi->inode_hash_lock);
413 hlist_for_each_entry(i, head, i_fat_hash) {
414 BUG_ON(i->vfs_inode.i_sb != sb);
415 if (i->i_pos != i_pos)
417 inode = igrab(&i->vfs_inode);
421 spin_unlock(&sbi->inode_hash_lock);
425 static int is_exec(unsigned char *extension)
427 unsigned char exe_extensions[] = "EXECOMBAT", *walk;
429 for (walk = exe_extensions; *walk; walk += 3)
430 if (!strncmp(extension, walk, 3))
435 static int fat_calc_dir_size(struct inode *inode)
437 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
438 int ret, fclus, dclus;
441 if (MSDOS_I(inode)->i_start == 0)
444 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
447 inode->i_size = (fclus + 1) << sbi->cluster_bits;
452 /* doesn't deal with root inode */
453 int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
455 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
458 MSDOS_I(inode)->i_pos = 0;
459 inode->i_uid = sbi->options.fs_uid;
460 inode->i_gid = sbi->options.fs_gid;
462 inode->i_generation = get_seconds();
464 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
465 inode->i_generation &= ~1;
466 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
467 inode->i_op = sbi->dir_ops;
468 inode->i_fop = &fat_dir_operations;
470 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
471 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
472 error = fat_calc_dir_size(inode);
475 MSDOS_I(inode)->mmu_private = inode->i_size;
477 set_nlink(inode, fat_subdirs(inode));
478 } else { /* not a directory */
479 inode->i_generation |= 1;
480 inode->i_mode = fat_make_mode(sbi, de->attr,
481 ((sbi->options.showexec && !is_exec(de->name + 8))
482 ? S_IRUGO|S_IWUGO : S_IRWXUGO));
483 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
485 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
486 inode->i_size = le32_to_cpu(de->size);
487 inode->i_op = &fat_file_inode_operations;
488 inode->i_fop = &fat_file_operations;
489 inode->i_mapping->a_ops = &fat_aops;
490 MSDOS_I(inode)->mmu_private = inode->i_size;
492 if (de->attr & ATTR_SYS) {
493 if (sbi->options.sys_immutable)
494 inode->i_flags |= S_IMMUTABLE;
496 fat_save_attrs(inode, de->attr);
498 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
499 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
501 fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0);
502 if (sbi->options.isvfat) {
503 fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime,
504 de->cdate, de->ctime_cs);
505 fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
507 inode->i_ctime = inode->i_atime = inode->i_mtime;
512 static inline void fat_lock_build_inode(struct msdos_sb_info *sbi)
514 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
515 mutex_lock(&sbi->nfs_build_inode_lock);
518 static inline void fat_unlock_build_inode(struct msdos_sb_info *sbi)
520 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
521 mutex_unlock(&sbi->nfs_build_inode_lock);
524 struct inode *fat_build_inode(struct super_block *sb,
525 struct msdos_dir_entry *de, loff_t i_pos)
530 fat_lock_build_inode(MSDOS_SB(sb));
531 inode = fat_iget(sb, i_pos);
534 inode = new_inode(sb);
536 inode = ERR_PTR(-ENOMEM);
539 inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
540 inode->i_version = 1;
541 err = fat_fill_inode(inode, de);
544 inode = ERR_PTR(err);
547 fat_attach(inode, i_pos);
548 insert_inode_hash(inode);
550 fat_unlock_build_inode(MSDOS_SB(sb));
554 EXPORT_SYMBOL_GPL(fat_build_inode);
556 static void fat_evict_inode(struct inode *inode)
558 truncate_inode_pages_final(&inode->i_data);
559 if (!inode->i_nlink) {
561 fat_truncate_blocks(inode, 0);
563 invalidate_inode_buffers(inode);
565 fat_cache_inval_inode(inode);
569 static void fat_set_state(struct super_block *sb,
570 unsigned int set, unsigned int force)
572 struct buffer_head *bh;
573 struct fat_boot_sector *b;
574 struct msdos_sb_info *sbi = MSDOS_SB(sb);
576 /* do not change any thing if mounted read only */
577 if ((sb->s_flags & MS_RDONLY) && !force)
580 /* do not change state if fs was dirty */
582 /* warn only on set (mount). */
584 fat_msg(sb, KERN_WARNING, "Volume was not properly "
585 "unmounted. Some data may be corrupt. "
590 bh = sb_bread(sb, 0);
592 fat_msg(sb, KERN_ERR, "unable to read boot sector "
593 "to mark fs as dirty");
597 b = (struct fat_boot_sector *) bh->b_data;
599 if (sbi->fat_bits == 32) {
601 b->fat32.state |= FAT_STATE_DIRTY;
603 b->fat32.state &= ~FAT_STATE_DIRTY;
604 } else /* fat 16 and 12 */ {
606 b->fat16.state |= FAT_STATE_DIRTY;
608 b->fat16.state &= ~FAT_STATE_DIRTY;
611 mark_buffer_dirty(bh);
612 sync_dirty_buffer(bh);
616 static void fat_reset_iocharset(struct fat_mount_options *opts)
618 if (opts->iocharset != fat_default_iocharset) {
619 /* Note: opts->iocharset can be NULL here */
620 kfree(opts->iocharset);
621 opts->iocharset = fat_default_iocharset;
625 static void delayed_free(struct rcu_head *p)
627 struct msdos_sb_info *sbi = container_of(p, struct msdos_sb_info, rcu);
628 unload_nls(sbi->nls_disk);
629 unload_nls(sbi->nls_io);
630 fat_reset_iocharset(&sbi->options);
634 static void fat_put_super(struct super_block *sb)
636 struct msdos_sb_info *sbi = MSDOS_SB(sb);
638 fat_set_state(sb, 0, 0);
640 iput(sbi->fsinfo_inode);
641 iput(sbi->fat_inode);
643 call_rcu(&sbi->rcu, delayed_free);
646 static struct kmem_cache *fat_inode_cachep;
648 static struct inode *fat_alloc_inode(struct super_block *sb)
650 struct msdos_inode_info *ei;
651 ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
655 init_rwsem(&ei->truncate_lock);
656 /* Zeroing to allow iput() even if partial initialized inode. */
663 return &ei->vfs_inode;
666 static void fat_i_callback(struct rcu_head *head)
668 struct inode *inode = container_of(head, struct inode, i_rcu);
669 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
672 static void fat_destroy_inode(struct inode *inode)
674 call_rcu(&inode->i_rcu, fat_i_callback);
677 static void init_once(void *foo)
679 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
681 spin_lock_init(&ei->cache_lru_lock);
683 ei->cache_valid_id = FAT_CACHE_VALID + 1;
684 INIT_LIST_HEAD(&ei->cache_lru);
685 INIT_HLIST_NODE(&ei->i_fat_hash);
686 INIT_HLIST_NODE(&ei->i_dir_hash);
687 inode_init_once(&ei->vfs_inode);
690 static int __init fat_init_inodecache(void)
692 fat_inode_cachep = kmem_cache_create("fat_inode_cache",
693 sizeof(struct msdos_inode_info),
694 0, (SLAB_RECLAIM_ACCOUNT|
697 if (fat_inode_cachep == NULL)
702 static void __exit fat_destroy_inodecache(void)
705 * Make sure all delayed rcu free inodes are flushed before we
709 kmem_cache_destroy(fat_inode_cachep);
712 static int fat_remount(struct super_block *sb, int *flags, char *data)
715 struct msdos_sb_info *sbi = MSDOS_SB(sb);
716 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME);
720 /* make sure we update state on remount. */
721 new_rdonly = *flags & MS_RDONLY;
722 if (new_rdonly != (sb->s_flags & MS_RDONLY)) {
724 fat_set_state(sb, 0, 0);
726 fat_set_state(sb, 1, 1);
731 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
733 struct super_block *sb = dentry->d_sb;
734 struct msdos_sb_info *sbi = MSDOS_SB(sb);
735 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
737 /* If the count of free cluster is still unknown, counts it here. */
738 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
739 int err = fat_count_free_clusters(dentry->d_sb);
744 buf->f_type = dentry->d_sb->s_magic;
745 buf->f_bsize = sbi->cluster_size;
746 buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
747 buf->f_bfree = sbi->free_clusters;
748 buf->f_bavail = sbi->free_clusters;
749 buf->f_fsid.val[0] = (u32)id;
750 buf->f_fsid.val[1] = (u32)(id >> 32);
752 (sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE;
757 static int __fat_write_inode(struct inode *inode, int wait)
759 struct super_block *sb = inode->i_sb;
760 struct msdos_sb_info *sbi = MSDOS_SB(sb);
761 struct buffer_head *bh;
762 struct msdos_dir_entry *raw_entry;
767 if (inode->i_ino == MSDOS_ROOT_INO)
771 i_pos = fat_i_pos_read(sbi, inode);
775 fat_get_blknr_offset(sbi, i_pos, &blocknr, &offset);
776 bh = sb_bread(sb, blocknr);
778 fat_msg(sb, KERN_ERR, "unable to read inode block "
779 "for updating (i_pos %lld)", i_pos);
782 spin_lock(&sbi->inode_hash_lock);
783 if (i_pos != MSDOS_I(inode)->i_pos) {
784 spin_unlock(&sbi->inode_hash_lock);
789 raw_entry = &((struct msdos_dir_entry *) (bh->b_data))[offset];
790 if (S_ISDIR(inode->i_mode))
793 raw_entry->size = cpu_to_le32(inode->i_size);
794 raw_entry->attr = fat_make_attrs(inode);
795 fat_set_start(raw_entry, MSDOS_I(inode)->i_logstart);
796 fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
797 &raw_entry->date, NULL);
798 if (sbi->options.isvfat) {
800 fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime,
801 &raw_entry->cdate, &raw_entry->ctime_cs);
802 fat_time_unix2fat(sbi, &inode->i_atime, &atime,
803 &raw_entry->adate, NULL);
805 spin_unlock(&sbi->inode_hash_lock);
806 mark_buffer_dirty(bh);
809 err = sync_dirty_buffer(bh);
814 static int fat_write_inode(struct inode *inode, struct writeback_control *wbc)
818 if (inode->i_ino == MSDOS_FSINFO_INO) {
819 struct super_block *sb = inode->i_sb;
821 mutex_lock(&MSDOS_SB(sb)->s_lock);
822 err = fat_clusters_flush(sb);
823 mutex_unlock(&MSDOS_SB(sb)->s_lock);
825 err = __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
830 int fat_sync_inode(struct inode *inode)
832 return __fat_write_inode(inode, 1);
835 EXPORT_SYMBOL_GPL(fat_sync_inode);
837 static int fat_show_options(struct seq_file *m, struct dentry *root);
838 static const struct super_operations fat_sops = {
839 .alloc_inode = fat_alloc_inode,
840 .destroy_inode = fat_destroy_inode,
841 .write_inode = fat_write_inode,
842 .evict_inode = fat_evict_inode,
843 .put_super = fat_put_super,
844 .statfs = fat_statfs,
845 .remount_fs = fat_remount,
847 .show_options = fat_show_options,
850 static int fat_show_options(struct seq_file *m, struct dentry *root)
852 struct msdos_sb_info *sbi = MSDOS_SB(root->d_sb);
853 struct fat_mount_options *opts = &sbi->options;
854 int isvfat = opts->isvfat;
856 if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
857 seq_printf(m, ",uid=%u",
858 from_kuid_munged(&init_user_ns, opts->fs_uid));
859 if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
860 seq_printf(m, ",gid=%u",
861 from_kgid_munged(&init_user_ns, opts->fs_gid));
862 seq_printf(m, ",fmask=%04o", opts->fs_fmask);
863 seq_printf(m, ",dmask=%04o", opts->fs_dmask);
864 if (opts->allow_utime)
865 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
867 /* strip "cp" prefix from displayed option */
868 seq_printf(m, ",codepage=%s", &sbi->nls_disk->charset[2]);
871 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
873 switch (opts->shortname) {
874 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
875 seq_puts(m, ",shortname=win95");
877 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
878 seq_puts(m, ",shortname=winnt");
880 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
881 seq_puts(m, ",shortname=mixed");
883 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
884 seq_puts(m, ",shortname=lower");
887 seq_puts(m, ",shortname=unknown");
891 if (opts->name_check != 'n')
892 seq_printf(m, ",check=%c", opts->name_check);
894 seq_puts(m, ",usefree");
896 seq_puts(m, ",quiet");
898 seq_puts(m, ",showexec");
899 if (opts->sys_immutable)
900 seq_puts(m, ",sys_immutable");
903 seq_puts(m, ",dotsOK=yes");
905 seq_puts(m, ",nocase");
908 seq_puts(m, ",utf8");
909 if (opts->unicode_xlate)
910 seq_puts(m, ",uni_xlate");
912 seq_puts(m, ",nonumtail");
914 seq_puts(m, ",rodir");
917 seq_puts(m, ",flush");
919 if (opts->time_offset)
920 seq_printf(m, ",time_offset=%d", opts->time_offset);
922 seq_puts(m, ",tz=UTC");
924 if (opts->errors == FAT_ERRORS_CONT)
925 seq_puts(m, ",errors=continue");
926 else if (opts->errors == FAT_ERRORS_PANIC)
927 seq_puts(m, ",errors=panic");
929 seq_puts(m, ",errors=remount-ro");
930 if (opts->nfs == FAT_NFS_NOSTALE_RO)
931 seq_puts(m, ",nfs=nostale_ro");
933 seq_puts(m, ",nfs=stale_rw");
935 seq_puts(m, ",discard");
936 if (opts->dos1xfloppy)
937 seq_puts(m, ",dos1xfloppy");
943 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
944 Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
945 Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
946 Opt_immutable, Opt_dots, Opt_nodots,
947 Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
948 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
949 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
950 Opt_obsolete, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
951 Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_time_offset,
952 Opt_nfs_stale_rw, Opt_nfs_nostale_ro, Opt_err, Opt_dos1xfloppy,
955 static const match_table_t fat_tokens = {
956 {Opt_check_r, "check=relaxed"},
957 {Opt_check_s, "check=strict"},
958 {Opt_check_n, "check=normal"},
959 {Opt_check_r, "check=r"},
960 {Opt_check_s, "check=s"},
961 {Opt_check_n, "check=n"},
964 {Opt_umask, "umask=%o"},
965 {Opt_dmask, "dmask=%o"},
966 {Opt_fmask, "fmask=%o"},
967 {Opt_allow_utime, "allow_utime=%o"},
968 {Opt_codepage, "codepage=%u"},
969 {Opt_usefree, "usefree"},
970 {Opt_nocase, "nocase"},
971 {Opt_quiet, "quiet"},
972 {Opt_showexec, "showexec"},
973 {Opt_debug, "debug"},
974 {Opt_immutable, "sys_immutable"},
975 {Opt_flush, "flush"},
976 {Opt_tz_utc, "tz=UTC"},
977 {Opt_time_offset, "time_offset=%d"},
978 {Opt_err_cont, "errors=continue"},
979 {Opt_err_panic, "errors=panic"},
980 {Opt_err_ro, "errors=remount-ro"},
981 {Opt_discard, "discard"},
982 {Opt_nfs_stale_rw, "nfs"},
983 {Opt_nfs_stale_rw, "nfs=stale_rw"},
984 {Opt_nfs_nostale_ro, "nfs=nostale_ro"},
985 {Opt_dos1xfloppy, "dos1xfloppy"},
986 {Opt_obsolete, "conv=binary"},
987 {Opt_obsolete, "conv=text"},
988 {Opt_obsolete, "conv=auto"},
989 {Opt_obsolete, "conv=b"},
990 {Opt_obsolete, "conv=t"},
991 {Opt_obsolete, "conv=a"},
992 {Opt_obsolete, "fat=%u"},
993 {Opt_obsolete, "blocksize=%u"},
994 {Opt_obsolete, "cvf_format=%20s"},
995 {Opt_obsolete, "cvf_options=%100s"},
996 {Opt_obsolete, "posix"},
999 static const match_table_t msdos_tokens = {
1000 {Opt_nodots, "nodots"},
1001 {Opt_nodots, "dotsOK=no"},
1003 {Opt_dots, "dotsOK=yes"},
1006 static const match_table_t vfat_tokens = {
1007 {Opt_charset, "iocharset=%s"},
1008 {Opt_shortname_lower, "shortname=lower"},
1009 {Opt_shortname_win95, "shortname=win95"},
1010 {Opt_shortname_winnt, "shortname=winnt"},
1011 {Opt_shortname_mixed, "shortname=mixed"},
1012 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */
1013 {Opt_utf8_no, "utf8=no"},
1014 {Opt_utf8_no, "utf8=false"},
1015 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */
1016 {Opt_utf8_yes, "utf8=yes"},
1017 {Opt_utf8_yes, "utf8=true"},
1018 {Opt_utf8_yes, "utf8"},
1019 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */
1020 {Opt_uni_xl_no, "uni_xlate=no"},
1021 {Opt_uni_xl_no, "uni_xlate=false"},
1022 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */
1023 {Opt_uni_xl_yes, "uni_xlate=yes"},
1024 {Opt_uni_xl_yes, "uni_xlate=true"},
1025 {Opt_uni_xl_yes, "uni_xlate"},
1026 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */
1027 {Opt_nonumtail_no, "nonumtail=no"},
1028 {Opt_nonumtail_no, "nonumtail=false"},
1029 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */
1030 {Opt_nonumtail_yes, "nonumtail=yes"},
1031 {Opt_nonumtail_yes, "nonumtail=true"},
1032 {Opt_nonumtail_yes, "nonumtail"},
1033 {Opt_rodir, "rodir"},
1037 static int parse_options(struct super_block *sb, char *options, int is_vfat,
1038 int silent, int *debug, struct fat_mount_options *opts)
1041 substring_t args[MAX_OPT_ARGS];
1045 opts->isvfat = is_vfat;
1047 opts->fs_uid = current_uid();
1048 opts->fs_gid = current_gid();
1049 opts->fs_fmask = opts->fs_dmask = current_umask();
1050 opts->allow_utime = -1;
1051 opts->codepage = fat_default_codepage;
1052 fat_reset_iocharset(opts);
1054 opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95;
1057 opts->shortname = 0;
1060 opts->name_check = 'n';
1061 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0;
1062 opts->utf8 = opts->unicode_xlate = 0;
1064 opts->usefree = opts->nocase = 0;
1067 opts->errors = FAT_ERRORS_RO;
1073 while ((p = strsep(&options, ",")) != NULL) {
1078 token = match_token(p, fat_tokens, args);
1079 if (token == Opt_err) {
1081 token = match_token(p, vfat_tokens, args);
1083 token = match_token(p, msdos_tokens, args);
1087 opts->name_check = 's';
1090 opts->name_check = 'r';
1093 opts->name_check = 'n';
1102 /* for backward compatibility */
1103 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1104 | VFAT_SFN_CREATE_WIN95;
1117 opts->sys_immutable = 1;
1120 if (match_int(&args[0], &option))
1122 opts->fs_uid = make_kuid(current_user_ns(), option);
1123 if (!uid_valid(opts->fs_uid))
1127 if (match_int(&args[0], &option))
1129 opts->fs_gid = make_kgid(current_user_ns(), option);
1130 if (!gid_valid(opts->fs_gid))
1134 if (match_octal(&args[0], &option))
1136 opts->fs_fmask = opts->fs_dmask = option;
1139 if (match_octal(&args[0], &option))
1141 opts->fs_dmask = option;
1144 if (match_octal(&args[0], &option))
1146 opts->fs_fmask = option;
1148 case Opt_allow_utime:
1149 if (match_octal(&args[0], &option))
1151 opts->allow_utime = option & (S_IWGRP | S_IWOTH);
1154 if (match_int(&args[0], &option))
1156 opts->codepage = option;
1161 case Opt_time_offset:
1162 if (match_int(&args[0], &option))
1164 if (option < -12 * 60 || option > 12 * 60)
1167 opts->time_offset = option;
1171 opts->time_offset = 0;
1174 opts->errors = FAT_ERRORS_CONT;
1177 opts->errors = FAT_ERRORS_PANIC;
1180 opts->errors = FAT_ERRORS_RO;
1182 case Opt_nfs_stale_rw:
1183 opts->nfs = FAT_NFS_STALE_RW;
1185 case Opt_nfs_nostale_ro:
1186 opts->nfs = FAT_NFS_NOSTALE_RO;
1188 case Opt_dos1xfloppy:
1189 opts->dos1xfloppy = 1;
1192 /* msdos specific */
1202 fat_reset_iocharset(opts);
1203 iocharset = match_strdup(&args[0]);
1206 opts->iocharset = iocharset;
1208 case Opt_shortname_lower:
1209 opts->shortname = VFAT_SFN_DISPLAY_LOWER
1210 | VFAT_SFN_CREATE_WIN95;
1212 case Opt_shortname_win95:
1213 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1214 | VFAT_SFN_CREATE_WIN95;
1216 case Opt_shortname_winnt:
1217 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1218 | VFAT_SFN_CREATE_WINNT;
1220 case Opt_shortname_mixed:
1221 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1222 | VFAT_SFN_CREATE_WIN95;
1224 case Opt_utf8_no: /* 0 or no or false */
1227 case Opt_utf8_yes: /* empty or 1 or yes or true */
1230 case Opt_uni_xl_no: /* 0 or no or false */
1231 opts->unicode_xlate = 0;
1233 case Opt_uni_xl_yes: /* empty or 1 or yes or true */
1234 opts->unicode_xlate = 1;
1236 case Opt_nonumtail_no: /* 0 or no or false */
1237 opts->numtail = 1; /* negated option */
1239 case Opt_nonumtail_yes: /* empty or 1 or yes or true */
1240 opts->numtail = 0; /* negated option */
1249 /* obsolete mount options */
1251 fat_msg(sb, KERN_INFO, "\"%s\" option is obsolete, "
1252 "not supported now", p);
1254 /* unknown option */
1257 fat_msg(sb, KERN_ERR,
1258 "Unrecognized mount option \"%s\" "
1259 "or missing value", p);
1266 /* UTF-8 doesn't provide FAT semantics */
1267 if (!strcmp(opts->iocharset, "utf8")) {
1268 fat_msg(sb, KERN_WARNING, "utf8 is not a recommended IO charset"
1269 " for FAT filesystems, filesystem will be "
1273 /* If user doesn't specify allow_utime, it's initialized from dmask. */
1274 if (opts->allow_utime == (unsigned short)-1)
1275 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1276 if (opts->unicode_xlate)
1278 if (opts->nfs == FAT_NFS_NOSTALE_RO) {
1279 sb->s_flags |= MS_RDONLY;
1280 sb->s_export_op = &fat_export_ops_nostale;
1286 static int fat_read_root(struct inode *inode)
1288 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
1291 MSDOS_I(inode)->i_pos = MSDOS_ROOT_INO;
1292 inode->i_uid = sbi->options.fs_uid;
1293 inode->i_gid = sbi->options.fs_gid;
1295 inode->i_generation = 0;
1296 inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
1297 inode->i_op = sbi->dir_ops;
1298 inode->i_fop = &fat_dir_operations;
1299 if (sbi->fat_bits == 32) {
1300 MSDOS_I(inode)->i_start = sbi->root_cluster;
1301 error = fat_calc_dir_size(inode);
1305 MSDOS_I(inode)->i_start = 0;
1306 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1308 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1309 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1310 MSDOS_I(inode)->i_logstart = 0;
1311 MSDOS_I(inode)->mmu_private = inode->i_size;
1313 fat_save_attrs(inode, ATTR_DIR);
1314 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1315 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1316 set_nlink(inode, fat_subdirs(inode)+2);
1321 static unsigned long calc_fat_clusters(struct super_block *sb)
1323 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1325 /* Divide first to avoid overflow */
1326 if (sbi->fat_bits != 12) {
1327 unsigned long ent_per_sec = sb->s_blocksize * 8 / sbi->fat_bits;
1328 return ent_per_sec * sbi->fat_length;
1331 return sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1334 static bool fat_bpb_is_zero(struct fat_boot_sector *b)
1336 if (get_unaligned_le16(&b->sector_size))
1338 if (b->sec_per_clus)
1344 if (get_unaligned_le16(&b->dir_entries))
1346 if (get_unaligned_le16(&b->sectors))
1359 static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b,
1360 int silent, struct fat_bios_param_block *bpb)
1362 int error = -EINVAL;
1364 /* Read in BPB ... */
1365 memset(bpb, 0, sizeof(*bpb));
1366 bpb->fat_sector_size = get_unaligned_le16(&b->sector_size);
1367 bpb->fat_sec_per_clus = b->sec_per_clus;
1368 bpb->fat_reserved = le16_to_cpu(b->reserved);
1369 bpb->fat_fats = b->fats;
1370 bpb->fat_dir_entries = get_unaligned_le16(&b->dir_entries);
1371 bpb->fat_sectors = get_unaligned_le16(&b->sectors);
1372 bpb->fat_fat_length = le16_to_cpu(b->fat_length);
1373 bpb->fat_total_sect = le32_to_cpu(b->total_sect);
1375 bpb->fat16_state = b->fat16.state;
1376 bpb->fat16_vol_id = get_unaligned_le32(b->fat16.vol_id);
1378 bpb->fat32_length = le32_to_cpu(b->fat32.length);
1379 bpb->fat32_root_cluster = le32_to_cpu(b->fat32.root_cluster);
1380 bpb->fat32_info_sector = le16_to_cpu(b->fat32.info_sector);
1381 bpb->fat32_state = b->fat32.state;
1382 bpb->fat32_vol_id = get_unaligned_le32(b->fat32.vol_id);
1384 /* Validate this looks like a FAT filesystem BPB */
1385 if (!bpb->fat_reserved) {
1387 fat_msg(sb, KERN_ERR,
1388 "bogus number of reserved sectors");
1391 if (!bpb->fat_fats) {
1393 fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
1398 * Earlier we checked here that b->secs_track and b->head are nonzero,
1399 * but it turns out valid FAT filesystems can have zero there.
1402 if (!fat_valid_media(b->media)) {
1404 fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
1405 (unsigned)b->media);
1409 if (!is_power_of_2(bpb->fat_sector_size)
1410 || (bpb->fat_sector_size < 512)
1411 || (bpb->fat_sector_size > 4096)) {
1413 fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
1414 (unsigned)bpb->fat_sector_size);
1418 if (!is_power_of_2(bpb->fat_sec_per_clus)) {
1420 fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
1421 (unsigned)bpb->fat_sec_per_clus);
1425 if (bpb->fat_fat_length == 0 && bpb->fat32_length == 0) {
1427 fat_msg(sb, KERN_ERR, "bogus number of FAT sectors");
1437 static int fat_read_static_bpb(struct super_block *sb,
1438 struct fat_boot_sector *b, int silent,
1439 struct fat_bios_param_block *bpb)
1441 static const char *notdos1x = "This doesn't look like a DOS 1.x volume";
1443 struct fat_floppy_defaults *fdefaults = NULL;
1444 int error = -EINVAL;
1448 bd_sects = i_size_read(sb->s_bdev->bd_inode) / SECTOR_SIZE;
1450 /* 16-bit DOS 1.x reliably wrote bootstrap short-jmp code */
1451 if (b->ignored[0] != 0xeb || b->ignored[2] != 0x90) {
1453 fat_msg(sb, KERN_ERR,
1454 "%s; no bootstrapping code", notdos1x);
1459 * If any value in this region is non-zero, it isn't archaic
1462 if (!fat_bpb_is_zero(b)) {
1464 fat_msg(sb, KERN_ERR,
1465 "%s; DOS 2.x BPB is non-zero", notdos1x);
1469 for (i = 0; i < ARRAY_SIZE(floppy_defaults); i++) {
1470 if (floppy_defaults[i].nr_sectors == bd_sects) {
1471 fdefaults = &floppy_defaults[i];
1476 if (fdefaults == NULL) {
1478 fat_msg(sb, KERN_WARNING,
1479 "This looks like a DOS 1.x volume, but isn't a recognized floppy size (%llu sectors)",
1485 fat_msg(sb, KERN_INFO,
1486 "This looks like a DOS 1.x volume; assuming default BPB values");
1488 memset(bpb, 0, sizeof(*bpb));
1489 bpb->fat_sector_size = SECTOR_SIZE;
1490 bpb->fat_sec_per_clus = fdefaults->sec_per_clus;
1491 bpb->fat_reserved = 1;
1493 bpb->fat_dir_entries = fdefaults->dir_entries;
1494 bpb->fat_sectors = fdefaults->nr_sectors;
1495 bpb->fat_fat_length = fdefaults->fat_length;
1504 * Read the super block of an MS-DOS FS.
1506 int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
1507 void (*setup)(struct super_block *))
1509 struct inode *root_inode = NULL, *fat_inode = NULL;
1510 struct inode *fsinfo_inode = NULL;
1511 struct buffer_head *bh;
1512 struct fat_bios_param_block bpb;
1513 struct msdos_sb_info *sbi;
1514 u16 logical_sector_size;
1515 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1521 * GFP_KERNEL is ok here, because while we do hold the
1522 * supeblock lock, memory pressure can't call back into
1523 * the filesystem, since we're only just about to mount
1524 * it and have no inodes etc active!
1526 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1529 sb->s_fs_info = sbi;
1531 sb->s_flags |= MS_NODIRATIME;
1532 sb->s_magic = MSDOS_SUPER_MAGIC;
1533 sb->s_op = &fat_sops;
1534 sb->s_export_op = &fat_export_ops;
1535 mutex_init(&sbi->nfs_build_inode_lock);
1536 ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
1537 DEFAULT_RATELIMIT_BURST);
1539 error = parse_options(sb, data, isvfat, silent, &debug, &sbi->options);
1543 setup(sb); /* flavour-specific stuff that needs options */
1546 sb_min_blocksize(sb, 512);
1547 bh = sb_bread(sb, 0);
1549 fat_msg(sb, KERN_ERR, "unable to read boot sector");
1553 error = fat_read_bpb(sb, (struct fat_boot_sector *)bh->b_data, silent,
1555 if (error == -EINVAL && sbi->options.dos1xfloppy)
1556 error = fat_read_static_bpb(sb,
1557 (struct fat_boot_sector *)bh->b_data, silent, &bpb);
1560 if (error == -EINVAL)
1565 logical_sector_size = bpb.fat_sector_size;
1566 sbi->sec_per_clus = bpb.fat_sec_per_clus;
1569 if (logical_sector_size < sb->s_blocksize) {
1570 fat_msg(sb, KERN_ERR, "logical sector size too small for device"
1571 " (logical sector size = %u)", logical_sector_size);
1575 if (logical_sector_size > sb->s_blocksize) {
1576 struct buffer_head *bh_resize;
1578 if (!sb_set_blocksize(sb, logical_sector_size)) {
1579 fat_msg(sb, KERN_ERR, "unable to set blocksize %u",
1580 logical_sector_size);
1584 /* Verify that the larger boot sector is fully readable */
1585 bh_resize = sb_bread(sb, 0);
1586 if (bh_resize == NULL) {
1587 fat_msg(sb, KERN_ERR, "unable to read boot sector"
1588 " (logical sector size = %lu)",
1595 mutex_init(&sbi->s_lock);
1596 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1597 sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1598 sbi->fats = bpb.fat_fats;
1599 sbi->fat_bits = 0; /* Don't know yet */
1600 sbi->fat_start = bpb.fat_reserved;
1601 sbi->fat_length = bpb.fat_fat_length;
1602 sbi->root_cluster = 0;
1603 sbi->free_clusters = -1; /* Don't know yet */
1604 sbi->free_clus_valid = 0;
1605 sbi->prev_free = FAT_START_ENT;
1606 sb->s_maxbytes = 0xffffffff;
1608 if (!sbi->fat_length && bpb.fat32_length) {
1609 struct fat_boot_fsinfo *fsinfo;
1610 struct buffer_head *fsinfo_bh;
1614 sbi->fat_length = bpb.fat32_length;
1615 sbi->root_cluster = bpb.fat32_root_cluster;
1617 /* MC - if info_sector is 0, don't multiply by 0 */
1618 sbi->fsinfo_sector = bpb.fat32_info_sector;
1619 if (sbi->fsinfo_sector == 0)
1620 sbi->fsinfo_sector = 1;
1622 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1623 if (fsinfo_bh == NULL) {
1624 fat_msg(sb, KERN_ERR, "bread failed, FSINFO block"
1625 " (sector = %lu)", sbi->fsinfo_sector);
1629 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1630 if (!IS_FSINFO(fsinfo)) {
1631 fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: "
1632 "0x%08x, 0x%08x (sector = %lu)",
1633 le32_to_cpu(fsinfo->signature1),
1634 le32_to_cpu(fsinfo->signature2),
1635 sbi->fsinfo_sector);
1637 if (sbi->options.usefree)
1638 sbi->free_clus_valid = 1;
1639 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1640 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1646 /* interpret volume ID as a little endian 32 bit integer */
1647 if (sbi->fat_bits == 32)
1648 sbi->vol_id = bpb.fat32_vol_id;
1649 else /* fat 16 or 12 */
1650 sbi->vol_id = bpb.fat16_vol_id;
1652 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1653 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1655 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1656 sbi->dir_entries = bpb.fat_dir_entries;
1657 if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1659 fat_msg(sb, KERN_ERR, "bogus directory-entries per block"
1660 " (%u)", sbi->dir_entries);
1664 rootdir_sectors = sbi->dir_entries
1665 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1666 sbi->data_start = sbi->dir_start + rootdir_sectors;
1667 total_sectors = bpb.fat_sectors;
1668 if (total_sectors == 0)
1669 total_sectors = bpb.fat_total_sect;
1671 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1673 if (sbi->fat_bits != 32)
1674 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1676 /* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
1677 if (sbi->fat_bits == 32)
1678 sbi->dirty = bpb.fat32_state & FAT_STATE_DIRTY;
1679 else /* fat 16 or 12 */
1680 sbi->dirty = bpb.fat16_state & FAT_STATE_DIRTY;
1682 /* check that FAT table does not overflow */
1683 fat_clusters = calc_fat_clusters(sb);
1684 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1685 if (total_clusters > MAX_FAT(sb)) {
1687 fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
1692 sbi->max_cluster = total_clusters + FAT_START_ENT;
1693 /* check the free_clusters, it's not necessarily correct */
1694 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1695 sbi->free_clusters = -1;
1696 /* check the prev_free, it's not necessarily correct */
1697 sbi->prev_free %= sbi->max_cluster;
1698 if (sbi->prev_free < FAT_START_ENT)
1699 sbi->prev_free = FAT_START_ENT;
1701 /* set up enough so that it can read an inode */
1704 fat_ent_access_init(sb);
1707 * The low byte of FAT's first entry must have same value with
1708 * media-field. But in real world, too many devices is
1709 * writing wrong value. So, removed that validity check.
1711 * if (FAT_FIRST_ENT(sb, media) != first)
1715 sprintf(buf, "cp%d", sbi->options.codepage);
1716 sbi->nls_disk = load_nls(buf);
1717 if (!sbi->nls_disk) {
1718 fat_msg(sb, KERN_ERR, "codepage %s not found", buf);
1722 /* FIXME: utf8 is using iocharset for upper/lower conversion */
1723 if (sbi->options.isvfat) {
1724 sbi->nls_io = load_nls(sbi->options.iocharset);
1726 fat_msg(sb, KERN_ERR, "IO charset %s not found",
1727 sbi->options.iocharset);
1733 fat_inode = new_inode(sb);
1736 sbi->fat_inode = fat_inode;
1738 fsinfo_inode = new_inode(sb);
1741 fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
1742 sbi->fsinfo_inode = fsinfo_inode;
1743 insert_inode_hash(fsinfo_inode);
1745 root_inode = new_inode(sb);
1748 root_inode->i_ino = MSDOS_ROOT_INO;
1749 root_inode->i_version = 1;
1750 error = fat_read_root(root_inode);
1756 insert_inode_hash(root_inode);
1757 fat_attach(root_inode, 0);
1758 sb->s_root = d_make_root(root_inode);
1760 fat_msg(sb, KERN_ERR, "get root inode failed");
1764 if (sbi->options.discard) {
1765 struct request_queue *q = bdev_get_queue(sb->s_bdev);
1766 if (!blk_queue_discard(q))
1767 fat_msg(sb, KERN_WARNING,
1768 "mounting with \"discard\" option, but "
1769 "the device does not support discard");
1772 fat_set_state(sb, 1, 0);
1778 fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem");
1785 unload_nls(sbi->nls_io);
1786 unload_nls(sbi->nls_disk);
1787 fat_reset_iocharset(&sbi->options);
1788 sb->s_fs_info = NULL;
1793 EXPORT_SYMBOL_GPL(fat_fill_super);
1796 * helper function for fat_flush_inodes. This writes both the inode
1797 * and the file data blocks, waiting for in flight data blocks before
1798 * the start of the call. It does not wait for any io started
1801 static int writeback_inode(struct inode *inode)
1806 /* if we used wait=1, sync_inode_metadata waits for the io for the
1807 * inode to finish. So wait=0 is sent down to sync_inode_metadata
1808 * and filemap_fdatawrite is used for the data blocks
1810 ret = sync_inode_metadata(inode, 0);
1812 ret = filemap_fdatawrite(inode->i_mapping);
1817 * write data and metadata corresponding to i1 and i2. The io is
1818 * started but we do not wait for any of it to finish.
1820 * filemap_flush is used for the block device, so if there is a dirty
1821 * page for a block already in flight, we will not wait and start the
1824 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1827 if (!MSDOS_SB(sb)->options.flush)
1830 ret = writeback_inode(i1);
1832 ret = writeback_inode(i2);
1834 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
1835 ret = filemap_flush(mapping);
1839 EXPORT_SYMBOL_GPL(fat_flush_inodes);
1841 static int __init init_fat_fs(void)
1845 err = fat_cache_init();
1849 err = fat_init_inodecache();
1856 fat_cache_destroy();
1860 static void __exit exit_fat_fs(void)
1862 fat_cache_destroy();
1863 fat_destroy_inodecache();
1866 module_init(init_fat_fs)
1867 module_exit(exit_fat_fs)
1869 MODULE_LICENSE("GPL");