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/init.h>
15 #include <linux/time.h>
16 #include <linux/slab.h>
17 #include <linux/seq_file.h>
18 #include <linux/pagemap.h>
19 #include <linux/mpage.h>
20 #include <linux/buffer_head.h>
21 #include <linux/mount.h>
22 #include <linux/aio.h>
23 #include <linux/vfs.h>
24 #include <linux/parser.h>
25 #include <linux/uio.h>
26 #include <linux/writeback.h>
27 #include <linux/log2.h>
28 #include <linux/hash.h>
29 #include <linux/blkdev.h>
30 #include <asm/unaligned.h>
33 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET
34 /* if user don't select VFAT, this is undefined. */
35 #define CONFIG_FAT_DEFAULT_IOCHARSET ""
38 #define KB_IN_SECTORS 2
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 static 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;
129 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
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 offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
148 /* TODO: multiple cluster allocation would be desirable. */
149 err = fat_add_cluster(inode);
153 /* available blocks on this cluster */
154 mapped_blocks = sbi->sec_per_clus - offset;
156 *max_blocks = min(mapped_blocks, *max_blocks);
157 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
158 MSDOS_I(inode)->i_disksize = MSDOS_I(inode)->mmu_private;
160 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
165 BUG_ON(*max_blocks != mapped_blocks);
166 set_buffer_new(bh_result);
167 map_bh(bh_result, sb, phys);
172 static int fat_get_block(struct inode *inode, sector_t iblock,
173 struct buffer_head *bh_result, int create)
175 struct super_block *sb = inode->i_sb;
176 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
179 err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create);
182 bh_result->b_size = max_blocks << sb->s_blocksize_bits;
186 static int fat_writepage(struct page *page, struct writeback_control *wbc)
188 return block_write_full_page(page, fat_get_block, wbc);
191 static int fat_writepages(struct address_space *mapping,
192 struct writeback_control *wbc)
194 return mpage_writepages(mapping, wbc, fat_get_block);
197 static int fat_readpage(struct file *file, struct page *page)
199 return mpage_readpage(page, fat_get_block);
202 static int fat_readpages(struct file *file, struct address_space *mapping,
203 struct list_head *pages, unsigned nr_pages)
205 return mpage_readpages(mapping, pages, nr_pages, fat_get_block);
208 static void fat_write_failed(struct address_space *mapping, loff_t to)
210 struct inode *inode = mapping->host;
212 if (to > inode->i_size) {
213 truncate_pagecache(inode, inode->i_size);
214 fat_truncate_blocks(inode, inode->i_size);
218 static int fat_write_begin(struct file *file, struct address_space *mapping,
219 loff_t pos, unsigned len, unsigned flags,
220 struct page **pagep, void **fsdata)
225 err = cont_write_begin(file, mapping, pos, len, flags,
226 pagep, fsdata, fat_get_block,
227 &MSDOS_I(mapping->host)->mmu_private);
229 fat_write_failed(mapping, pos + len);
233 static int fat_write_end(struct file *file, struct address_space *mapping,
234 loff_t pos, unsigned len, unsigned copied,
235 struct page *pagep, void *fsdata)
237 struct inode *inode = mapping->host;
239 err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
241 fat_write_failed(mapping, pos + len);
242 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
243 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
244 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
245 mark_inode_dirty(inode);
250 static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
251 struct iov_iter *iter,
254 struct file *file = iocb->ki_filp;
255 struct address_space *mapping = file->f_mapping;
256 struct inode *inode = mapping->host;
257 size_t count = iov_iter_count(iter);
262 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
263 * so we need to update the ->mmu_private to block boundary.
265 * But we must fill the remaining area or hole by nul for
266 * updating ->mmu_private.
268 * Return 0, and fallback to normal buffered write.
270 loff_t size = offset + count;
271 if (MSDOS_I(inode)->mmu_private < size)
276 * FAT need to use the DIO_LOCKING for avoiding the race
277 * condition of fat_get_block() and ->truncate().
279 ret = blockdev_direct_IO(rw, iocb, inode, iter, offset, fat_get_block);
280 if (ret < 0 && (rw & WRITE))
281 fat_write_failed(mapping, offset + count);
286 static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
290 /* fat_get_cluster() assumes the requested blocknr isn't truncated. */
291 down_read(&MSDOS_I(mapping->host)->truncate_lock);
292 blocknr = generic_block_bmap(mapping, block, fat_get_block);
293 up_read(&MSDOS_I(mapping->host)->truncate_lock);
298 static const struct address_space_operations fat_aops = {
299 .readpage = fat_readpage,
300 .readpages = fat_readpages,
301 .writepage = fat_writepage,
302 .writepages = fat_writepages,
303 .write_begin = fat_write_begin,
304 .write_end = fat_write_end,
305 .direct_IO = fat_direct_IO,
310 * New FAT inode stuff. We do the following:
311 * a) i_ino is constant and has nothing with on-disk location.
312 * b) FAT manages its own cache of directory entries.
313 * c) *This* cache is indexed by on-disk location.
314 * d) inode has an associated directory entry, all right, but
315 * it may be unhashed.
316 * e) currently entries are stored within struct inode. That should
318 * f) we deal with races in the following way:
319 * 1. readdir() and lookup() do FAT-dir-cache lookup.
320 * 2. rename() unhashes the F-d-c entry and rehashes it in
322 * 3. unlink() and rmdir() unhash F-d-c entry.
323 * 4. fat_write_inode() checks whether the thing is unhashed.
324 * If it is we silently return. If it isn't we do bread(),
325 * check if the location is still valid and retry if it
326 * isn't. Otherwise we do changes.
327 * 5. Spinlock is used to protect hash/unhash/location check/lookup
328 * 6. fat_evict_inode() unhashes the F-d-c entry.
329 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry
330 * and consider negative result as cache miss.
333 static void fat_hash_init(struct super_block *sb)
335 struct msdos_sb_info *sbi = MSDOS_SB(sb);
338 spin_lock_init(&sbi->inode_hash_lock);
339 for (i = 0; i < FAT_HASH_SIZE; i++)
340 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
343 static inline unsigned long fat_hash(loff_t i_pos)
345 return hash_32(i_pos, FAT_HASH_BITS);
348 static void dir_hash_init(struct super_block *sb)
350 struct msdos_sb_info *sbi = MSDOS_SB(sb);
353 spin_lock_init(&sbi->dir_hash_lock);
354 for (i = 0; i < FAT_HASH_SIZE; i++)
355 INIT_HLIST_HEAD(&sbi->dir_hashtable[i]);
358 void fat_attach(struct inode *inode, loff_t i_pos)
360 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
362 if (inode->i_ino != MSDOS_ROOT_INO) {
363 struct hlist_head *head = sbi->inode_hashtable
366 spin_lock(&sbi->inode_hash_lock);
367 MSDOS_I(inode)->i_pos = i_pos;
368 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
369 spin_unlock(&sbi->inode_hash_lock);
372 /* If NFS support is enabled, cache the mapping of start cluster
373 * to directory inode. This is used during reconnection of
374 * dentries to the filesystem root.
376 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
377 struct hlist_head *d_head = sbi->dir_hashtable;
378 d_head += fat_dir_hash(MSDOS_I(inode)->i_logstart);
380 spin_lock(&sbi->dir_hash_lock);
381 hlist_add_head(&MSDOS_I(inode)->i_dir_hash, d_head);
382 spin_unlock(&sbi->dir_hash_lock);
385 EXPORT_SYMBOL_GPL(fat_attach);
387 void fat_detach(struct inode *inode)
389 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
390 spin_lock(&sbi->inode_hash_lock);
391 MSDOS_I(inode)->i_pos = 0;
392 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
393 spin_unlock(&sbi->inode_hash_lock);
395 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
396 spin_lock(&sbi->dir_hash_lock);
397 hlist_del_init(&MSDOS_I(inode)->i_dir_hash);
398 spin_unlock(&sbi->dir_hash_lock);
401 EXPORT_SYMBOL_GPL(fat_detach);
403 struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
405 struct msdos_sb_info *sbi = MSDOS_SB(sb);
406 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
407 struct msdos_inode_info *i;
408 struct inode *inode = NULL;
410 spin_lock(&sbi->inode_hash_lock);
411 hlist_for_each_entry(i, head, i_fat_hash) {
412 BUG_ON(i->vfs_inode.i_sb != sb);
413 if (i->i_pos != i_pos)
415 inode = igrab(&i->vfs_inode);
419 spin_unlock(&sbi->inode_hash_lock);
423 static int is_exec(unsigned char *extension)
425 unsigned char exe_extensions[] = "EXECOMBAT", *walk;
427 for (walk = exe_extensions; *walk; walk += 3)
428 if (!strncmp(extension, walk, 3))
433 static int fat_calc_dir_size(struct inode *inode)
435 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
436 int ret, fclus, dclus;
439 if (MSDOS_I(inode)->i_start == 0)
442 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
445 inode->i_size = (fclus + 1) << sbi->cluster_bits;
450 /* doesn't deal with root inode */
451 int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
453 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
456 MSDOS_I(inode)->i_pos = 0;
457 inode->i_uid = sbi->options.fs_uid;
458 inode->i_gid = sbi->options.fs_gid;
460 inode->i_generation = get_seconds();
462 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
463 inode->i_generation &= ~1;
464 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
465 inode->i_op = sbi->dir_ops;
466 inode->i_fop = &fat_dir_operations;
468 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
469 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
470 error = fat_calc_dir_size(inode);
474 set_nlink(inode, fat_subdirs(inode));
475 } else { /* not a directory */
476 inode->i_generation |= 1;
477 inode->i_mode = fat_make_mode(sbi, de->attr,
478 ((sbi->options.showexec && !is_exec(de->name + 8))
479 ? S_IRUGO|S_IWUGO : S_IRWXUGO));
480 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
482 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
483 inode->i_size = le32_to_cpu(de->size);
484 inode->i_op = &fat_file_inode_operations;
485 inode->i_fop = &fat_file_operations;
486 inode->i_mapping->a_ops = &fat_aops;
489 MSDOS_I(inode)->mmu_private = inode->i_size;
490 MSDOS_I(inode)->i_disksize = round_up(inode->i_size,
491 inode->i_sb->s_blocksize);
493 if (de->attr & ATTR_SYS) {
494 if (sbi->options.sys_immutable)
495 inode->i_flags |= S_IMMUTABLE;
497 fat_save_attrs(inode, de->attr);
499 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
500 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
502 fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0);
503 if (sbi->options.isvfat) {
504 fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime,
505 de->cdate, de->ctime_cs);
506 fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
508 inode->i_ctime = inode->i_atime = inode->i_mtime;
513 static inline void fat_lock_build_inode(struct msdos_sb_info *sbi)
515 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
516 mutex_lock(&sbi->nfs_build_inode_lock);
519 static inline void fat_unlock_build_inode(struct msdos_sb_info *sbi)
521 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
522 mutex_unlock(&sbi->nfs_build_inode_lock);
525 struct inode *fat_build_inode(struct super_block *sb,
526 struct msdos_dir_entry *de, loff_t i_pos)
531 fat_lock_build_inode(MSDOS_SB(sb));
532 inode = fat_iget(sb, i_pos);
535 inode = new_inode(sb);
537 inode = ERR_PTR(-ENOMEM);
540 inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
541 inode->i_version = 1;
542 err = fat_fill_inode(inode, de);
545 inode = ERR_PTR(err);
548 fat_attach(inode, i_pos);
549 insert_inode_hash(inode);
551 fat_unlock_build_inode(MSDOS_SB(sb));
555 EXPORT_SYMBOL_GPL(fat_build_inode);
557 static void fat_evict_inode(struct inode *inode)
559 truncate_inode_pages_final(&inode->i_data);
560 if (!inode->i_nlink) {
562 fat_truncate_blocks(inode, 0);
564 invalidate_inode_buffers(inode);
566 fat_cache_inval_inode(inode);
570 static void fat_set_state(struct super_block *sb,
571 unsigned int set, unsigned int force)
573 struct buffer_head *bh;
574 struct fat_boot_sector *b;
575 struct msdos_sb_info *sbi = sb->s_fs_info;
577 /* do not change any thing if mounted read only */
578 if ((sb->s_flags & MS_RDONLY) && !force)
581 /* do not change state if fs was dirty */
583 /* warn only on set (mount). */
585 fat_msg(sb, KERN_WARNING, "Volume was not properly "
586 "unmounted. Some data may be corrupt. "
591 bh = sb_bread(sb, 0);
593 fat_msg(sb, KERN_ERR, "unable to read boot sector "
594 "to mark fs as dirty");
598 b = (struct fat_boot_sector *) bh->b_data;
600 if (sbi->fat_bits == 32) {
602 b->fat32.state |= FAT_STATE_DIRTY;
604 b->fat32.state &= ~FAT_STATE_DIRTY;
605 } else /* fat 16 and 12 */ {
607 b->fat16.state |= FAT_STATE_DIRTY;
609 b->fat16.state &= ~FAT_STATE_DIRTY;
612 mark_buffer_dirty(bh);
613 sync_dirty_buffer(bh);
617 static void delayed_free(struct rcu_head *p)
619 struct msdos_sb_info *sbi = container_of(p, struct msdos_sb_info, rcu);
620 unload_nls(sbi->nls_disk);
621 unload_nls(sbi->nls_io);
622 if (sbi->options.iocharset != fat_default_iocharset)
623 kfree(sbi->options.iocharset);
627 static void fat_put_super(struct super_block *sb)
629 struct msdos_sb_info *sbi = MSDOS_SB(sb);
631 fat_set_state(sb, 0, 0);
633 iput(sbi->fsinfo_inode);
634 iput(sbi->fat_inode);
636 call_rcu(&sbi->rcu, delayed_free);
639 static struct kmem_cache *fat_inode_cachep;
641 static struct inode *fat_alloc_inode(struct super_block *sb)
643 struct msdos_inode_info *ei;
644 ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
648 init_rwsem(&ei->truncate_lock);
649 return &ei->vfs_inode;
652 static void fat_i_callback(struct rcu_head *head)
654 struct inode *inode = container_of(head, struct inode, i_rcu);
655 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
658 static void fat_destroy_inode(struct inode *inode)
660 call_rcu(&inode->i_rcu, fat_i_callback);
663 static void init_once(void *foo)
665 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
667 spin_lock_init(&ei->cache_lru_lock);
669 ei->cache_valid_id = FAT_CACHE_VALID + 1;
670 INIT_LIST_HEAD(&ei->cache_lru);
671 INIT_HLIST_NODE(&ei->i_fat_hash);
672 INIT_HLIST_NODE(&ei->i_dir_hash);
673 inode_init_once(&ei->vfs_inode);
676 static int __init fat_init_inodecache(void)
678 fat_inode_cachep = kmem_cache_create("fat_inode_cache",
679 sizeof(struct msdos_inode_info),
680 0, (SLAB_RECLAIM_ACCOUNT|
683 if (fat_inode_cachep == NULL)
688 static void __exit fat_destroy_inodecache(void)
691 * Make sure all delayed rcu free inodes are flushed before we
695 kmem_cache_destroy(fat_inode_cachep);
698 static int fat_remount(struct super_block *sb, int *flags, char *data)
701 struct msdos_sb_info *sbi = MSDOS_SB(sb);
702 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME);
706 /* make sure we update state on remount. */
707 new_rdonly = *flags & MS_RDONLY;
708 if (new_rdonly != (sb->s_flags & MS_RDONLY)) {
710 fat_set_state(sb, 0, 0);
712 fat_set_state(sb, 1, 1);
717 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
719 struct super_block *sb = dentry->d_sb;
720 struct msdos_sb_info *sbi = MSDOS_SB(sb);
721 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
723 /* If the count of free cluster is still unknown, counts it here. */
724 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
725 int err = fat_count_free_clusters(dentry->d_sb);
730 buf->f_type = dentry->d_sb->s_magic;
731 buf->f_bsize = sbi->cluster_size;
732 buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
733 buf->f_bfree = sbi->free_clusters;
734 buf->f_bavail = sbi->free_clusters;
735 buf->f_fsid.val[0] = (u32)id;
736 buf->f_fsid.val[1] = (u32)(id >> 32);
738 (sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE;
743 static int __fat_write_inode(struct inode *inode, int wait)
745 struct super_block *sb = inode->i_sb;
746 struct msdos_sb_info *sbi = MSDOS_SB(sb);
747 struct buffer_head *bh;
748 struct msdos_dir_entry *raw_entry;
753 if (inode->i_ino == MSDOS_ROOT_INO)
757 i_pos = fat_i_pos_read(sbi, inode);
761 fat_get_blknr_offset(sbi, i_pos, &blocknr, &offset);
762 bh = sb_bread(sb, blocknr);
764 fat_msg(sb, KERN_ERR, "unable to read inode block "
765 "for updating (i_pos %lld)", i_pos);
768 spin_lock(&sbi->inode_hash_lock);
769 if (i_pos != MSDOS_I(inode)->i_pos) {
770 spin_unlock(&sbi->inode_hash_lock);
775 raw_entry = &((struct msdos_dir_entry *) (bh->b_data))[offset];
776 if (S_ISDIR(inode->i_mode))
779 raw_entry->size = cpu_to_le32(inode->i_size);
780 raw_entry->attr = fat_make_attrs(inode);
781 fat_set_start(raw_entry, MSDOS_I(inode)->i_logstart);
782 fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
783 &raw_entry->date, NULL);
784 if (sbi->options.isvfat) {
786 fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime,
787 &raw_entry->cdate, &raw_entry->ctime_cs);
788 fat_time_unix2fat(sbi, &inode->i_atime, &atime,
789 &raw_entry->adate, NULL);
791 spin_unlock(&sbi->inode_hash_lock);
792 mark_buffer_dirty(bh);
795 err = sync_dirty_buffer(bh);
800 static int fat_write_inode(struct inode *inode, struct writeback_control *wbc)
804 if (inode->i_ino == MSDOS_FSINFO_INO) {
805 struct super_block *sb = inode->i_sb;
807 mutex_lock(&MSDOS_SB(sb)->s_lock);
808 err = fat_clusters_flush(sb);
809 mutex_unlock(&MSDOS_SB(sb)->s_lock);
811 err = __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
816 int fat_sync_inode(struct inode *inode)
818 return __fat_write_inode(inode, 1);
821 EXPORT_SYMBOL_GPL(fat_sync_inode);
823 static int fat_show_options(struct seq_file *m, struct dentry *root);
824 static const struct super_operations fat_sops = {
825 .alloc_inode = fat_alloc_inode,
826 .destroy_inode = fat_destroy_inode,
827 .write_inode = fat_write_inode,
828 .evict_inode = fat_evict_inode,
829 .put_super = fat_put_super,
830 .statfs = fat_statfs,
831 .remount_fs = fat_remount,
833 .show_options = fat_show_options,
836 static int fat_show_options(struct seq_file *m, struct dentry *root)
838 struct msdos_sb_info *sbi = MSDOS_SB(root->d_sb);
839 struct fat_mount_options *opts = &sbi->options;
840 int isvfat = opts->isvfat;
842 if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
843 seq_printf(m, ",uid=%u",
844 from_kuid_munged(&init_user_ns, opts->fs_uid));
845 if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
846 seq_printf(m, ",gid=%u",
847 from_kgid_munged(&init_user_ns, opts->fs_gid));
848 seq_printf(m, ",fmask=%04o", opts->fs_fmask);
849 seq_printf(m, ",dmask=%04o", opts->fs_dmask);
850 if (opts->allow_utime)
851 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
853 /* strip "cp" prefix from displayed option */
854 seq_printf(m, ",codepage=%s", &sbi->nls_disk->charset[2]);
857 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
859 switch (opts->shortname) {
860 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
861 seq_puts(m, ",shortname=win95");
863 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
864 seq_puts(m, ",shortname=winnt");
866 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
867 seq_puts(m, ",shortname=mixed");
869 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
870 seq_puts(m, ",shortname=lower");
873 seq_puts(m, ",shortname=unknown");
877 if (opts->name_check != 'n')
878 seq_printf(m, ",check=%c", opts->name_check);
880 seq_puts(m, ",usefree");
882 seq_puts(m, ",quiet");
884 seq_puts(m, ",showexec");
885 if (opts->sys_immutable)
886 seq_puts(m, ",sys_immutable");
889 seq_puts(m, ",dotsOK=yes");
891 seq_puts(m, ",nocase");
894 seq_puts(m, ",utf8");
895 if (opts->unicode_xlate)
896 seq_puts(m, ",uni_xlate");
898 seq_puts(m, ",nonumtail");
900 seq_puts(m, ",rodir");
903 seq_puts(m, ",flush");
905 if (opts->time_offset)
906 seq_printf(m, ",time_offset=%d", opts->time_offset);
908 seq_puts(m, ",tz=UTC");
910 if (opts->errors == FAT_ERRORS_CONT)
911 seq_puts(m, ",errors=continue");
912 else if (opts->errors == FAT_ERRORS_PANIC)
913 seq_puts(m, ",errors=panic");
915 seq_puts(m, ",errors=remount-ro");
916 if (opts->nfs == FAT_NFS_NOSTALE_RO)
917 seq_puts(m, ",nfs=nostale_ro");
919 seq_puts(m, ",nfs=stale_rw");
921 seq_puts(m, ",discard");
922 if (opts->dos1xfloppy)
923 seq_puts(m, ",dos1xfloppy");
929 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
930 Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
931 Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
932 Opt_immutable, Opt_dots, Opt_nodots,
933 Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
934 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
935 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
936 Opt_obsolete, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
937 Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_time_offset,
938 Opt_nfs_stale_rw, Opt_nfs_nostale_ro, Opt_err, Opt_dos1xfloppy,
941 static const match_table_t fat_tokens = {
942 {Opt_check_r, "check=relaxed"},
943 {Opt_check_s, "check=strict"},
944 {Opt_check_n, "check=normal"},
945 {Opt_check_r, "check=r"},
946 {Opt_check_s, "check=s"},
947 {Opt_check_n, "check=n"},
950 {Opt_umask, "umask=%o"},
951 {Opt_dmask, "dmask=%o"},
952 {Opt_fmask, "fmask=%o"},
953 {Opt_allow_utime, "allow_utime=%o"},
954 {Opt_codepage, "codepage=%u"},
955 {Opt_usefree, "usefree"},
956 {Opt_nocase, "nocase"},
957 {Opt_quiet, "quiet"},
958 {Opt_showexec, "showexec"},
959 {Opt_debug, "debug"},
960 {Opt_immutable, "sys_immutable"},
961 {Opt_flush, "flush"},
962 {Opt_tz_utc, "tz=UTC"},
963 {Opt_time_offset, "time_offset=%d"},
964 {Opt_err_cont, "errors=continue"},
965 {Opt_err_panic, "errors=panic"},
966 {Opt_err_ro, "errors=remount-ro"},
967 {Opt_discard, "discard"},
968 {Opt_nfs_stale_rw, "nfs"},
969 {Opt_nfs_stale_rw, "nfs=stale_rw"},
970 {Opt_nfs_nostale_ro, "nfs=nostale_ro"},
971 {Opt_dos1xfloppy, "dos1xfloppy"},
972 {Opt_obsolete, "conv=binary"},
973 {Opt_obsolete, "conv=text"},
974 {Opt_obsolete, "conv=auto"},
975 {Opt_obsolete, "conv=b"},
976 {Opt_obsolete, "conv=t"},
977 {Opt_obsolete, "conv=a"},
978 {Opt_obsolete, "fat=%u"},
979 {Opt_obsolete, "blocksize=%u"},
980 {Opt_obsolete, "cvf_format=%20s"},
981 {Opt_obsolete, "cvf_options=%100s"},
982 {Opt_obsolete, "posix"},
985 static const match_table_t msdos_tokens = {
986 {Opt_nodots, "nodots"},
987 {Opt_nodots, "dotsOK=no"},
989 {Opt_dots, "dotsOK=yes"},
992 static const match_table_t vfat_tokens = {
993 {Opt_charset, "iocharset=%s"},
994 {Opt_shortname_lower, "shortname=lower"},
995 {Opt_shortname_win95, "shortname=win95"},
996 {Opt_shortname_winnt, "shortname=winnt"},
997 {Opt_shortname_mixed, "shortname=mixed"},
998 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */
999 {Opt_utf8_no, "utf8=no"},
1000 {Opt_utf8_no, "utf8=false"},
1001 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */
1002 {Opt_utf8_yes, "utf8=yes"},
1003 {Opt_utf8_yes, "utf8=true"},
1004 {Opt_utf8_yes, "utf8"},
1005 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */
1006 {Opt_uni_xl_no, "uni_xlate=no"},
1007 {Opt_uni_xl_no, "uni_xlate=false"},
1008 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */
1009 {Opt_uni_xl_yes, "uni_xlate=yes"},
1010 {Opt_uni_xl_yes, "uni_xlate=true"},
1011 {Opt_uni_xl_yes, "uni_xlate"},
1012 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */
1013 {Opt_nonumtail_no, "nonumtail=no"},
1014 {Opt_nonumtail_no, "nonumtail=false"},
1015 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */
1016 {Opt_nonumtail_yes, "nonumtail=yes"},
1017 {Opt_nonumtail_yes, "nonumtail=true"},
1018 {Opt_nonumtail_yes, "nonumtail"},
1019 {Opt_rodir, "rodir"},
1023 static int parse_options(struct super_block *sb, char *options, int is_vfat,
1024 int silent, int *debug, struct fat_mount_options *opts)
1027 substring_t args[MAX_OPT_ARGS];
1031 opts->isvfat = is_vfat;
1033 opts->fs_uid = current_uid();
1034 opts->fs_gid = current_gid();
1035 opts->fs_fmask = opts->fs_dmask = current_umask();
1036 opts->allow_utime = -1;
1037 opts->codepage = fat_default_codepage;
1038 opts->iocharset = fat_default_iocharset;
1040 opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95;
1043 opts->shortname = 0;
1046 opts->name_check = 'n';
1047 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0;
1048 opts->utf8 = opts->unicode_xlate = 0;
1050 opts->usefree = opts->nocase = 0;
1053 opts->errors = FAT_ERRORS_RO;
1059 while ((p = strsep(&options, ",")) != NULL) {
1064 token = match_token(p, fat_tokens, args);
1065 if (token == Opt_err) {
1067 token = match_token(p, vfat_tokens, args);
1069 token = match_token(p, msdos_tokens, args);
1073 opts->name_check = 's';
1076 opts->name_check = 'r';
1079 opts->name_check = 'n';
1088 /* for backward compatibility */
1089 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1090 | VFAT_SFN_CREATE_WIN95;
1103 opts->sys_immutable = 1;
1106 if (match_int(&args[0], &option))
1108 opts->fs_uid = make_kuid(current_user_ns(), option);
1109 if (!uid_valid(opts->fs_uid))
1113 if (match_int(&args[0], &option))
1115 opts->fs_gid = make_kgid(current_user_ns(), option);
1116 if (!gid_valid(opts->fs_gid))
1120 if (match_octal(&args[0], &option))
1122 opts->fs_fmask = opts->fs_dmask = option;
1125 if (match_octal(&args[0], &option))
1127 opts->fs_dmask = option;
1130 if (match_octal(&args[0], &option))
1132 opts->fs_fmask = option;
1134 case Opt_allow_utime:
1135 if (match_octal(&args[0], &option))
1137 opts->allow_utime = option & (S_IWGRP | S_IWOTH);
1140 if (match_int(&args[0], &option))
1142 opts->codepage = option;
1147 case Opt_time_offset:
1148 if (match_int(&args[0], &option))
1150 if (option < -12 * 60 || option > 12 * 60)
1153 opts->time_offset = option;
1157 opts->time_offset = 0;
1160 opts->errors = FAT_ERRORS_CONT;
1163 opts->errors = FAT_ERRORS_PANIC;
1166 opts->errors = FAT_ERRORS_RO;
1168 case Opt_nfs_stale_rw:
1169 opts->nfs = FAT_NFS_STALE_RW;
1171 case Opt_nfs_nostale_ro:
1172 opts->nfs = FAT_NFS_NOSTALE_RO;
1174 case Opt_dos1xfloppy:
1175 opts->dos1xfloppy = 1;
1178 /* msdos specific */
1188 if (opts->iocharset != fat_default_iocharset)
1189 kfree(opts->iocharset);
1190 iocharset = match_strdup(&args[0]);
1193 opts->iocharset = iocharset;
1195 case Opt_shortname_lower:
1196 opts->shortname = VFAT_SFN_DISPLAY_LOWER
1197 | VFAT_SFN_CREATE_WIN95;
1199 case Opt_shortname_win95:
1200 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1201 | VFAT_SFN_CREATE_WIN95;
1203 case Opt_shortname_winnt:
1204 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1205 | VFAT_SFN_CREATE_WINNT;
1207 case Opt_shortname_mixed:
1208 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1209 | VFAT_SFN_CREATE_WIN95;
1211 case Opt_utf8_no: /* 0 or no or false */
1214 case Opt_utf8_yes: /* empty or 1 or yes or true */
1217 case Opt_uni_xl_no: /* 0 or no or false */
1218 opts->unicode_xlate = 0;
1220 case Opt_uni_xl_yes: /* empty or 1 or yes or true */
1221 opts->unicode_xlate = 1;
1223 case Opt_nonumtail_no: /* 0 or no or false */
1224 opts->numtail = 1; /* negated option */
1226 case Opt_nonumtail_yes: /* empty or 1 or yes or true */
1227 opts->numtail = 0; /* negated option */
1236 /* obsolete mount options */
1238 fat_msg(sb, KERN_INFO, "\"%s\" option is obsolete, "
1239 "not supported now", p);
1241 /* unknown option */
1244 fat_msg(sb, KERN_ERR,
1245 "Unrecognized mount option \"%s\" "
1246 "or missing value", p);
1253 /* UTF-8 doesn't provide FAT semantics */
1254 if (!strcmp(opts->iocharset, "utf8")) {
1255 fat_msg(sb, KERN_WARNING, "utf8 is not a recommended IO charset"
1256 " for FAT filesystems, filesystem will be "
1260 /* If user doesn't specify allow_utime, it's initialized from dmask. */
1261 if (opts->allow_utime == (unsigned short)-1)
1262 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1263 if (opts->unicode_xlate)
1265 if (opts->nfs == FAT_NFS_NOSTALE_RO) {
1266 sb->s_flags |= MS_RDONLY;
1267 sb->s_export_op = &fat_export_ops_nostale;
1273 static int fat_read_root(struct inode *inode)
1275 struct super_block *sb = inode->i_sb;
1276 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1279 MSDOS_I(inode)->i_pos = MSDOS_ROOT_INO;
1280 inode->i_uid = sbi->options.fs_uid;
1281 inode->i_gid = sbi->options.fs_gid;
1283 inode->i_generation = 0;
1284 inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
1285 inode->i_op = sbi->dir_ops;
1286 inode->i_fop = &fat_dir_operations;
1287 if (sbi->fat_bits == 32) {
1288 MSDOS_I(inode)->i_start = sbi->root_cluster;
1289 error = fat_calc_dir_size(inode);
1293 MSDOS_I(inode)->i_start = 0;
1294 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1296 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1297 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1298 MSDOS_I(inode)->i_logstart = 0;
1299 MSDOS_I(inode)->mmu_private = inode->i_size;
1300 MSDOS_I(inode)->i_disksize = inode->i_size;
1302 fat_save_attrs(inode, ATTR_DIR);
1303 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1304 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1305 set_nlink(inode, fat_subdirs(inode)+2);
1310 static unsigned long calc_fat_clusters(struct super_block *sb)
1312 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1314 /* Divide first to avoid overflow */
1315 if (sbi->fat_bits != 12) {
1316 unsigned long ent_per_sec = sb->s_blocksize * 8 / sbi->fat_bits;
1317 return ent_per_sec * sbi->fat_length;
1320 return sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1323 static bool fat_bpb_is_zero(struct fat_boot_sector *b)
1325 if (get_unaligned_le16(&b->sector_size))
1327 if (b->sec_per_clus)
1333 if (get_unaligned_le16(&b->dir_entries))
1335 if (get_unaligned_le16(&b->sectors))
1348 static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b,
1349 int silent, struct fat_bios_param_block *bpb)
1351 int error = -EINVAL;
1353 /* Read in BPB ... */
1354 memset(bpb, 0, sizeof(*bpb));
1355 bpb->fat_sector_size = get_unaligned_le16(&b->sector_size);
1356 bpb->fat_sec_per_clus = b->sec_per_clus;
1357 bpb->fat_reserved = le16_to_cpu(b->reserved);
1358 bpb->fat_fats = b->fats;
1359 bpb->fat_dir_entries = get_unaligned_le16(&b->dir_entries);
1360 bpb->fat_sectors = get_unaligned_le16(&b->sectors);
1361 bpb->fat_fat_length = le16_to_cpu(b->fat_length);
1362 bpb->fat_total_sect = le32_to_cpu(b->total_sect);
1364 bpb->fat16_state = b->fat16.state;
1365 bpb->fat16_vol_id = get_unaligned_le32(b->fat16.vol_id);
1367 bpb->fat32_length = le32_to_cpu(b->fat32.length);
1368 bpb->fat32_root_cluster = le32_to_cpu(b->fat32.root_cluster);
1369 bpb->fat32_info_sector = le16_to_cpu(b->fat32.info_sector);
1370 bpb->fat32_state = b->fat32.state;
1371 bpb->fat32_vol_id = get_unaligned_le32(b->fat32.vol_id);
1373 /* Validate this looks like a FAT filesystem BPB */
1374 if (!bpb->fat_reserved) {
1376 fat_msg(sb, KERN_ERR,
1377 "bogus number of reserved sectors");
1380 if (!bpb->fat_fats) {
1382 fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
1387 * Earlier we checked here that b->secs_track and b->head are nonzero,
1388 * but it turns out valid FAT filesystems can have zero there.
1391 if (!fat_valid_media(b->media)) {
1393 fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
1394 (unsigned)b->media);
1398 if (!is_power_of_2(bpb->fat_sector_size)
1399 || (bpb->fat_sector_size < 512)
1400 || (bpb->fat_sector_size > 4096)) {
1402 fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
1403 (unsigned)bpb->fat_sector_size);
1407 if (!is_power_of_2(bpb->fat_sec_per_clus)) {
1409 fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
1410 (unsigned)bpb->fat_sec_per_clus);
1420 static int fat_read_static_bpb(struct super_block *sb,
1421 struct fat_boot_sector *b, int silent,
1422 struct fat_bios_param_block *bpb)
1424 static const char *notdos1x = "This doesn't look like a DOS 1.x volume";
1426 struct fat_floppy_defaults *fdefaults = NULL;
1427 int error = -EINVAL;
1431 bd_sects = i_size_read(sb->s_bdev->bd_inode) / SECTOR_SIZE;
1433 /* 16-bit DOS 1.x reliably wrote bootstrap short-jmp code */
1434 if (b->ignored[0] != 0xeb || b->ignored[2] != 0x90) {
1436 fat_msg(sb, KERN_ERR,
1437 "%s; no bootstrapping code", notdos1x);
1442 * If any value in this region is non-zero, it isn't archaic
1445 if (!fat_bpb_is_zero(b)) {
1447 fat_msg(sb, KERN_ERR,
1448 "%s; DOS 2.x BPB is non-zero", notdos1x);
1452 for (i = 0; i < ARRAY_SIZE(floppy_defaults); i++) {
1453 if (floppy_defaults[i].nr_sectors == bd_sects) {
1454 fdefaults = &floppy_defaults[i];
1459 if (fdefaults == NULL) {
1461 fat_msg(sb, KERN_WARNING,
1462 "This looks like a DOS 1.x volume, but isn't a recognized floppy size (%llu sectors)",
1468 fat_msg(sb, KERN_INFO,
1469 "This looks like a DOS 1.x volume; assuming default BPB values");
1471 memset(bpb, 0, sizeof(*bpb));
1472 bpb->fat_sector_size = SECTOR_SIZE;
1473 bpb->fat_sec_per_clus = fdefaults->sec_per_clus;
1474 bpb->fat_reserved = 1;
1476 bpb->fat_dir_entries = fdefaults->dir_entries;
1477 bpb->fat_sectors = fdefaults->nr_sectors;
1478 bpb->fat_fat_length = fdefaults->fat_length;
1487 * Read the super block of an MS-DOS FS.
1489 int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
1490 void (*setup)(struct super_block *))
1492 struct inode *root_inode = NULL, *fat_inode = NULL;
1493 struct inode *fsinfo_inode = NULL;
1494 struct buffer_head *bh;
1495 struct fat_bios_param_block bpb;
1496 struct msdos_sb_info *sbi;
1497 u16 logical_sector_size;
1498 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1504 * GFP_KERNEL is ok here, because while we do hold the
1505 * supeblock lock, memory pressure can't call back into
1506 * the filesystem, since we're only just about to mount
1507 * it and have no inodes etc active!
1509 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1512 sb->s_fs_info = sbi;
1514 sb->s_flags |= MS_NODIRATIME;
1515 sb->s_magic = MSDOS_SUPER_MAGIC;
1516 sb->s_op = &fat_sops;
1517 sb->s_export_op = &fat_export_ops;
1518 mutex_init(&sbi->nfs_build_inode_lock);
1519 ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
1520 DEFAULT_RATELIMIT_BURST);
1522 error = parse_options(sb, data, isvfat, silent, &debug, &sbi->options);
1526 setup(sb); /* flavour-specific stuff that needs options */
1529 sb_min_blocksize(sb, 512);
1530 bh = sb_bread(sb, 0);
1532 fat_msg(sb, KERN_ERR, "unable to read boot sector");
1536 error = fat_read_bpb(sb, (struct fat_boot_sector *)bh->b_data, silent,
1538 if (error == -EINVAL && sbi->options.dos1xfloppy)
1539 error = fat_read_static_bpb(sb,
1540 (struct fat_boot_sector *)bh->b_data, silent, &bpb);
1543 if (error == -EINVAL)
1548 logical_sector_size = bpb.fat_sector_size;
1549 sbi->sec_per_clus = bpb.fat_sec_per_clus;
1552 if (logical_sector_size < sb->s_blocksize) {
1553 fat_msg(sb, KERN_ERR, "logical sector size too small for device"
1554 " (logical sector size = %u)", logical_sector_size);
1558 if (logical_sector_size > sb->s_blocksize) {
1559 struct buffer_head *bh_resize;
1561 if (!sb_set_blocksize(sb, logical_sector_size)) {
1562 fat_msg(sb, KERN_ERR, "unable to set blocksize %u",
1563 logical_sector_size);
1567 /* Verify that the larger boot sector is fully readable */
1568 bh_resize = sb_bread(sb, 0);
1569 if (bh_resize == NULL) {
1570 fat_msg(sb, KERN_ERR, "unable to read boot sector"
1571 " (logical sector size = %lu)",
1578 mutex_init(&sbi->s_lock);
1579 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1580 sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1581 sbi->fats = bpb.fat_fats;
1582 sbi->fat_bits = 0; /* Don't know yet */
1583 sbi->fat_start = bpb.fat_reserved;
1584 sbi->fat_length = bpb.fat_fat_length;
1585 sbi->root_cluster = 0;
1586 sbi->free_clusters = -1; /* Don't know yet */
1587 sbi->free_clus_valid = 0;
1588 sbi->prev_free = FAT_START_ENT;
1589 sb->s_maxbytes = 0xffffffff;
1591 if (!sbi->fat_length && bpb.fat32_length) {
1592 struct fat_boot_fsinfo *fsinfo;
1593 struct buffer_head *fsinfo_bh;
1597 sbi->fat_length = bpb.fat32_length;
1598 sbi->root_cluster = bpb.fat32_root_cluster;
1600 /* MC - if info_sector is 0, don't multiply by 0 */
1601 sbi->fsinfo_sector = bpb.fat32_info_sector;
1602 if (sbi->fsinfo_sector == 0)
1603 sbi->fsinfo_sector = 1;
1605 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1606 if (fsinfo_bh == NULL) {
1607 fat_msg(sb, KERN_ERR, "bread failed, FSINFO block"
1608 " (sector = %lu)", sbi->fsinfo_sector);
1612 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1613 if (!IS_FSINFO(fsinfo)) {
1614 fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: "
1615 "0x%08x, 0x%08x (sector = %lu)",
1616 le32_to_cpu(fsinfo->signature1),
1617 le32_to_cpu(fsinfo->signature2),
1618 sbi->fsinfo_sector);
1620 if (sbi->options.usefree)
1621 sbi->free_clus_valid = 1;
1622 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1623 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1629 /* interpret volume ID as a little endian 32 bit integer */
1630 if (sbi->fat_bits == 32)
1631 sbi->vol_id = bpb.fat32_vol_id;
1632 else /* fat 16 or 12 */
1633 sbi->vol_id = bpb.fat16_vol_id;
1635 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1636 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1638 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1639 sbi->dir_entries = bpb.fat_dir_entries;
1640 if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1642 fat_msg(sb, KERN_ERR, "bogus directory-entries per block"
1643 " (%u)", sbi->dir_entries);
1647 rootdir_sectors = sbi->dir_entries
1648 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1649 sbi->data_start = sbi->dir_start + rootdir_sectors;
1650 total_sectors = bpb.fat_sectors;
1651 if (total_sectors == 0)
1652 total_sectors = bpb.fat_total_sect;
1654 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1656 if (sbi->fat_bits != 32)
1657 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1659 /* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
1660 if (sbi->fat_bits == 32)
1661 sbi->dirty = bpb.fat32_state & FAT_STATE_DIRTY;
1662 else /* fat 16 or 12 */
1663 sbi->dirty = bpb.fat16_state & FAT_STATE_DIRTY;
1665 /* check that FAT table does not overflow */
1666 fat_clusters = calc_fat_clusters(sb);
1667 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1668 if (total_clusters > MAX_FAT(sb)) {
1670 fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
1675 sbi->max_cluster = total_clusters + FAT_START_ENT;
1676 /* check the free_clusters, it's not necessarily correct */
1677 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1678 sbi->free_clusters = -1;
1679 /* check the prev_free, it's not necessarily correct */
1680 sbi->prev_free %= sbi->max_cluster;
1681 if (sbi->prev_free < FAT_START_ENT)
1682 sbi->prev_free = FAT_START_ENT;
1684 /* set up enough so that it can read an inode */
1687 fat_ent_access_init(sb);
1690 * The low byte of FAT's first entry must have same value with
1691 * media-field. But in real world, too many devices is
1692 * writing wrong value. So, removed that validity check.
1694 * if (FAT_FIRST_ENT(sb, media) != first)
1698 sprintf(buf, "cp%d", sbi->options.codepage);
1699 sbi->nls_disk = load_nls(buf);
1700 if (!sbi->nls_disk) {
1701 fat_msg(sb, KERN_ERR, "codepage %s not found", buf);
1705 /* FIXME: utf8 is using iocharset for upper/lower conversion */
1706 if (sbi->options.isvfat) {
1707 sbi->nls_io = load_nls(sbi->options.iocharset);
1709 fat_msg(sb, KERN_ERR, "IO charset %s not found",
1710 sbi->options.iocharset);
1716 fat_inode = new_inode(sb);
1719 MSDOS_I(fat_inode)->i_pos = 0;
1720 sbi->fat_inode = fat_inode;
1722 fsinfo_inode = new_inode(sb);
1725 fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
1726 sbi->fsinfo_inode = fsinfo_inode;
1727 insert_inode_hash(fsinfo_inode);
1729 root_inode = new_inode(sb);
1732 root_inode->i_ino = MSDOS_ROOT_INO;
1733 root_inode->i_version = 1;
1734 error = fat_read_root(root_inode);
1740 insert_inode_hash(root_inode);
1741 fat_attach(root_inode, 0);
1742 sb->s_root = d_make_root(root_inode);
1744 fat_msg(sb, KERN_ERR, "get root inode failed");
1748 if (sbi->options.discard) {
1749 struct request_queue *q = bdev_get_queue(sb->s_bdev);
1750 if (!blk_queue_discard(q))
1751 fat_msg(sb, KERN_WARNING,
1752 "mounting with \"discard\" option, but "
1753 "the device does not support discard");
1756 fat_set_state(sb, 1, 0);
1762 fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem");
1769 unload_nls(sbi->nls_io);
1770 unload_nls(sbi->nls_disk);
1771 if (sbi->options.iocharset != fat_default_iocharset)
1772 kfree(sbi->options.iocharset);
1773 sb->s_fs_info = NULL;
1778 EXPORT_SYMBOL_GPL(fat_fill_super);
1781 * helper function for fat_flush_inodes. This writes both the inode
1782 * and the file data blocks, waiting for in flight data blocks before
1783 * the start of the call. It does not wait for any io started
1786 static int writeback_inode(struct inode *inode)
1791 /* if we used wait=1, sync_inode_metadata waits for the io for the
1792 * inode to finish. So wait=0 is sent down to sync_inode_metadata
1793 * and filemap_fdatawrite is used for the data blocks
1795 ret = sync_inode_metadata(inode, 0);
1797 ret = filemap_fdatawrite(inode->i_mapping);
1802 * write data and metadata corresponding to i1 and i2. The io is
1803 * started but we do not wait for any of it to finish.
1805 * filemap_flush is used for the block device, so if there is a dirty
1806 * page for a block already in flight, we will not wait and start the
1809 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1812 if (!MSDOS_SB(sb)->options.flush)
1815 ret = writeback_inode(i1);
1817 ret = writeback_inode(i2);
1819 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
1820 ret = filemap_flush(mapping);
1824 EXPORT_SYMBOL_GPL(fat_flush_inodes);
1826 static int __init init_fat_fs(void)
1830 err = fat_cache_init();
1834 err = fat_init_inodecache();
1841 fat_cache_destroy();
1845 static void __exit exit_fat_fs(void)
1847 fat_cache_destroy();
1848 fat_destroy_inodecache();
1851 module_init(init_fat_fs)
1852 module_exit(exit_fat_fs)
1854 MODULE_LICENSE("GPL");