[net-next-2.6.git] / fs / fat / namei_msdos.c

/*
 *  linux/fs/msdos/namei.c
 *
 *  Written 1992,1993 by Werner Almesberger
 *  Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu>
 *  Rewritten for constant inumbers 1999 by Al Viro
 */

#include <linux/module.h>
#include <linux/time.h>
#include <linux/buffer_head.h>
#include "fat.h"

/* Characters that are undesirable in an MS-DOS file name */
static unsigned char bad_chars[] = "*?<>|\"";
static unsigned char bad_if_strict[] = "+=,; ";

/***** Formats an MS-DOS file name. Rejects invalid names. */
static int msdos_format_name(const unsigned char *name, int len,
			     unsigned char *res, struct fat_mount_options *opts)
	/*
	 * name is the proposed name, len is its length, res is
	 * the resulting name, opts->name_check is either (r)elaxed,
	 * (n)ormal or (s)trict, opts->dotsOK allows dots at the
	 * beginning of name (for hidden files)
	 */
{
	unsigned char *walk;
	unsigned char c;
	int space;

	if (name[0] == '.') {	/* dotfile because . and .. already done */
		if (opts->dotsOK) {
			/* Get rid of dot - test for it elsewhere */
			name++;
			len--;
		} else
			return -EINVAL;
	}
	/*
	 * disallow names that _really_ start with a dot
	 */
	space = 1;
	c = 0;
	for (walk = res; len && walk - res < 8; walk++) {
		c = *name++;
		len--;
		if (opts->name_check != 'r' && strchr(bad_chars, c))
			return -EINVAL;
		if (opts->name_check == 's' && strchr(bad_if_strict, c))
			return -EINVAL;
		if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
			return -EINVAL;
		if (c < ' ' || c == ':' || c == '\\')
			return -EINVAL;
	/*
	 * 0xE5 is legal as a first character, but we must substitute
	 * 0x05 because 0xE5 marks deleted files.  Yes, DOS really
	 * does this.
	 * It seems that Microsoft hacked DOS to support non-US
	 * characters after the 0xE5 character was already in use to
	 * mark deleted files.
	 */
		if ((res == walk) && (c == 0xE5))
			c = 0x05;
		if (c == '.')
			break;
		space = (c == ' ');
		*walk = (!opts->nocase && c >= 'a' && c <= 'z') ? c - 32 : c;
	}
	if (space)
		return -EINVAL;
	if (opts->name_check == 's' && len && c != '.') {
		c = *name++;
		len--;
		if (c != '.')
			return -EINVAL;
	}
	while (c != '.' && len--)
		c = *name++;
	if (c == '.') {
		while (walk - res < 8)
			*walk++ = ' ';
		while (len > 0 && walk - res < MSDOS_NAME) {
			c = *name++;
			len--;
			if (opts->name_check != 'r' && strchr(bad_chars, c))
				return -EINVAL;
			if (opts->name_check == 's' &&
			    strchr(bad_if_strict, c))
				return -EINVAL;
			if (c < ' ' || c == ':' || c == '\\')
				return -EINVAL;
			if (c == '.') {
				if (opts->name_check == 's')
					return -EINVAL;
				break;
			}
			if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
				return -EINVAL;
			space = c == ' ';
			if (!opts->nocase && c >= 'a' && c <= 'z')
				*walk++ = c - 32;
			else
				*walk++ = c;
		}
		if (space)
			return -EINVAL;
		if (opts->name_check == 's' && len)
			return -EINVAL;
	}
	while (walk - res < MSDOS_NAME)
		*walk++ = ' ';

	return 0;
}

/***** Locates a directory entry.  Uses unformatted name. */
static int msdos_find(struct inode *dir, const unsigned char *name, int len,
		      struct fat_slot_info *sinfo)
{
	struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
	unsigned char msdos_name[MSDOS_NAME];
	int err;

	err = msdos_format_name(name, len, msdos_name, &sbi->options);
	if (err)
		return -ENOENT;

	err = fat_scan(dir, msdos_name, sinfo);
	if (!err && sbi->options.dotsOK) {
		if (name[0] == '.') {
			if (!(sinfo->de->attr & ATTR_HIDDEN))
				err = -ENOENT;
		} else {
			if (sinfo->de->attr & ATTR_HIDDEN)
				err = -ENOENT;
		}
		if (err)
			brelse(sinfo->bh);
	}
	return err;
}

/*
 * Compute the hash for the msdos name corresponding to the dentry.
 * Note: if the name is invalid, we leave the hash code unchanged so
 * that the existing dentry can be used. The msdos fs routines will
 * return ENOENT or EINVAL as appropriate.
 */
static int msdos_hash(struct dentry *dentry, struct qstr *qstr)
{
	struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
	unsigned char msdos_name[MSDOS_NAME];
	int error;

	error = msdos_format_name(qstr->name, qstr->len, msdos_name, options);
	if (!error)
		qstr->hash = full_name_hash(msdos_name, MSDOS_NAME);
	return 0;
}

/*
 * Compare two msdos names. If either of the names are invalid,
 * we fall back to doing the standard name comparison.
 */
static int msdos_cmp(struct dentry *dentry, struct qstr *a, struct qstr *b)
{
	struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
	unsigned char a_msdos_name[MSDOS_NAME], b_msdos_name[MSDOS_NAME];
	int error;

	error = msdos_format_name(a->name, a->len, a_msdos_name, options);
	if (error)
		goto old_compare;
	error = msdos_format_name(b->name, b->len, b_msdos_name, options);
	if (error)
		goto old_compare;
	error = memcmp(a_msdos_name, b_msdos_name, MSDOS_NAME);
out:
	return error;

old_compare:
	error = 1;
	if (a->len == b->len)
		error = memcmp(a->name, b->name, a->len);
	goto out;
}

static const struct dentry_operations msdos_dentry_operations = {
	.d_hash		= msdos_hash,
	.d_compare	= msdos_cmp,
};

/*
 * AV. Wrappers for FAT sb operations. Is it wise?
 */

/***** Get inode using directory and name */
static struct dentry *msdos_lookup(struct inode *dir, struct dentry *dentry,
				   struct nameidata *nd)
{
	struct super_block *sb = dir->i_sb;
	struct fat_slot_info sinfo;
	struct inode *inode;
	int err;

	lock_super(sb);

	err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
	if (err) {
		if (err == -ENOENT) {
			inode = NULL;
			goto out;
		}
		goto error;
	}

	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
	brelse(sinfo.bh);
	if (IS_ERR(inode)) {
		err = PTR_ERR(inode);
		goto error;
	}
out:
	unlock_super(sb);
	dentry->d_op = &msdos_dentry_operations;
	dentry = d_splice_alias(inode, dentry);
	if (dentry)
		dentry->d_op = &msdos_dentry_operations;
	return dentry;

error:
	unlock_super(sb);
	return ERR_PTR(err);
}

/***** Creates a directory entry (name is already formatted). */
static int msdos_add_entry(struct inode *dir, const unsigned char *name,
			   int is_dir, int is_hid, int cluster,
			   struct timespec *ts, struct fat_slot_info *sinfo)
{
	struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
	struct msdos_dir_entry de;
	__le16 time, date;
	int err;

	memcpy(de.name, name, MSDOS_NAME);
	de.attr = is_dir ? ATTR_DIR : ATTR_ARCH;
	if (is_hid)
		de.attr |= ATTR_HIDDEN;
	de.lcase = 0;
	fat_time_unix2fat(sbi, ts, &time, &date, NULL);
	de.cdate = de.adate = 0;
	de.ctime = 0;
	de.ctime_cs = 0;
	de.time = time;
	de.date = date;
	de.start = cpu_to_le16(cluster);
	de.starthi = cpu_to_le16(cluster >> 16);
	de.size = 0;

	err = fat_add_entries(dir, &de, 1, sinfo);
	if (err)
		return err;

	dir->i_ctime = dir->i_mtime = *ts;
	if (IS_DIRSYNC(dir))
		(void)fat_sync_inode(dir);
	else
		mark_inode_dirty(dir);

	return 0;
}

/***** Create a file */
static int msdos_create(struct inode *dir, struct dentry *dentry, int mode,
			struct nameidata *nd)
{
	struct super_block *sb = dir->i_sb;
	struct inode *inode = NULL;
	struct fat_slot_info sinfo;
	struct timespec ts;
	unsigned char msdos_name[MSDOS_NAME];
	int err, is_hid;

	lock_super(sb);

	err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
				msdos_name, &MSDOS_SB(sb)->options);
	if (err)
		goto out;
	is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
	/* Have to do it due to foo vs. .foo conflicts */
	if (!fat_scan(dir, msdos_name, &sinfo)) {
		brelse(sinfo.bh);
		err = -EINVAL;
		goto out;
	}

	ts = CURRENT_TIME_SEC;
	err = msdos_add_entry(dir, msdos_name, 0, is_hid, 0, &ts, &sinfo);
	if (err)
		goto out;
	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
	brelse(sinfo.bh);
	if (IS_ERR(inode)) {
		err = PTR_ERR(inode);
		goto out;
	}
	inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
	/* timestamp is already written, so mark_inode_dirty() is unneeded. */

	d_instantiate(dentry, inode);
out:
	unlock_super(sb);
	if (!err)
		err = fat_flush_inodes(sb, dir, inode);
	return err;
}

/***** Remove a directory */
static int msdos_rmdir(struct inode *dir, struct dentry *dentry)
{
	struct super_block *sb = dir->i_sb;
	struct inode *inode = dentry->d_inode;
	struct fat_slot_info sinfo;
	int err;

	lock_super(sb);
	/*
	 * Check whether the directory is not in use, then check
	 * whether it is empty.
	 */
	err = fat_dir_empty(inode);
	if (err)
		goto out;
	err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
	if (err)
		goto out;

	err = fat_remove_entries(dir, &sinfo);	/* and releases bh */
	if (err)
		goto out;
	drop_nlink(dir);

	clear_nlink(inode);
	inode->i_ctime = CURRENT_TIME_SEC;
	fat_detach(inode);
out:
	unlock_super(sb);
	if (!err)
		err = fat_flush_inodes(sb, dir, inode);

	return err;
}

/***** Make a directory */
static int msdos_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
	struct super_block *sb = dir->i_sb;
	struct fat_slot_info sinfo;
	struct inode *inode;
	unsigned char msdos_name[MSDOS_NAME];
	struct timespec ts;
	int err, is_hid, cluster;

	lock_super(sb);

	err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
				msdos_name, &MSDOS_SB(sb)->options);
	if (err)
		goto out;
	is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
	/* foo vs .foo situation */
	if (!fat_scan(dir, msdos_name, &sinfo)) {
		brelse(sinfo.bh);
		err = -EINVAL;
		goto out;
	}

	ts = CURRENT_TIME_SEC;
	cluster = fat_alloc_new_dir(dir, &ts);
	if (cluster < 0) {
		err = cluster;
		goto out;
	}
	err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
	if (err)
		goto out_free;
	inc_nlink(dir);

	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
	brelse(sinfo.bh);
	if (IS_ERR(inode)) {
		err = PTR_ERR(inode);
		/* the directory was completed, just return a error */
		goto out;
	}
	inode->i_nlink = 2;
	inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
	/* timestamp is already written, so mark_inode_dirty() is unneeded. */

	d_instantiate(dentry, inode);

	unlock_super(sb);
	fat_flush_inodes(sb, dir, inode);
	return 0;

out_free:
	fat_free_clusters(dir, cluster);
out:
	unlock_super(sb);
	return err;
}

/***** Unlink a file */
static int msdos_unlink(struct inode *dir, struct dentry *dentry)
{
	struct inode *inode = dentry->d_inode;
	struct super_block *sb= inode->i_sb;
	struct fat_slot_info sinfo;
	int err;

	lock_super(sb);
	err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
	if (err)
		goto out;

	err = fat_remove_entries(dir, &sinfo);	/* and releases bh */
	if (err)
		goto out;
	clear_nlink(inode);
	inode->i_ctime = CURRENT_TIME_SEC;
	fat_detach(inode);
out:
	unlock_super(sb);
	if (!err)
		err = fat_flush_inodes(sb, dir, inode);

	return err;
}

static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
			   struct dentry *old_dentry,
			   struct inode *new_dir, unsigned char *new_name,
			   struct dentry *new_dentry, int is_hid)
{
	struct buffer_head *dotdot_bh;
	struct msdos_dir_entry *dotdot_de;
	struct inode *old_inode, *new_inode;
	struct fat_slot_info old_sinfo, sinfo;
	struct timespec ts;
	loff_t dotdot_i_pos, new_i_pos;
	int err, old_attrs, is_dir, update_dotdot, corrupt = 0;

	old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
	old_inode = old_dentry->d_inode;
	new_inode = new_dentry->d_inode;

	err = fat_scan(old_dir, old_name, &old_sinfo);
	if (err) {
		err = -EIO;
		goto out;
	}

	is_dir = S_ISDIR(old_inode->i_mode);
	update_dotdot = (is_dir && old_dir != new_dir);
	if (update_dotdot) {
		if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de,
					 &dotdot_i_pos) < 0) {
			err = -EIO;
			goto out;
		}
	}

	old_attrs = MSDOS_I(old_inode)->i_attrs;
	err = fat_scan(new_dir, new_name, &sinfo);
	if (!err) {
		if (!new_inode) {
			/* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
			if (sinfo.de != old_sinfo.de) {
				err = -EINVAL;
				goto out;
			}
			if (is_hid)
				MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
			else
				MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
			if (IS_DIRSYNC(old_dir)) {
				err = fat_sync_inode(old_inode);
				if (err) {
					MSDOS_I(old_inode)->i_attrs = old_attrs;
					goto out;
				}
			} else
				mark_inode_dirty(old_inode);

			old_dir->i_version++;
			old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
			if (IS_DIRSYNC(old_dir))
				(void)fat_sync_inode(old_dir);
			else
				mark_inode_dirty(old_dir);
			goto out;
		}
	}

	ts = CURRENT_TIME_SEC;
	if (new_inode) {
		if (err)
			goto out;
		if (is_dir) {
			err = fat_dir_empty(new_inode);
			if (err)
				goto out;
		}
		new_i_pos = MSDOS_I(new_inode)->i_pos;
		fat_detach(new_inode);
	} else {
		err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
				      &ts, &sinfo);
		if (err)
			goto out;
		new_i_pos = sinfo.i_pos;
	}
	new_dir->i_version++;

	fat_detach(old_inode);
	fat_attach(old_inode, new_i_pos);
	if (is_hid)
		MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
	else
		MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
	if (IS_DIRSYNC(new_dir)) {
		err = fat_sync_inode(old_inode);
		if (err)
			goto error_inode;
	} else
		mark_inode_dirty(old_inode);

	if (update_dotdot) {
		int start = MSDOS_I(new_dir)->i_logstart;
		dotdot_de->start = cpu_to_le16(start);
		dotdot_de->starthi = cpu_to_le16(start >> 16);
		mark_buffer_dirty_inode(dotdot_bh, old_inode);
		if (IS_DIRSYNC(new_dir)) {
			err = sync_dirty_buffer(dotdot_bh);
			if (err)
				goto error_dotdot;
		}
		drop_nlink(old_dir);
		if (!new_inode)
			inc_nlink(new_dir);
	}

	err = fat_remove_entries(old_dir, &old_sinfo);	/* and releases bh */
	old_sinfo.bh = NULL;
	if (err)
		goto error_dotdot;
	old_dir->i_version++;
	old_dir->i_ctime = old_dir->i_mtime = ts;
	if (IS_DIRSYNC(old_dir))
		(void)fat_sync_inode(old_dir);
	else
		mark_inode_dirty(old_dir);

	if (new_inode) {
		drop_nlink(new_inode);
		if (is_dir)
			drop_nlink(new_inode);
		new_inode->i_ctime = ts;
	}
out:
	brelse(sinfo.bh);
	brelse(dotdot_bh);
	brelse(old_sinfo.bh);
	return err;

error_dotdot:
	/* data cluster is shared, serious corruption */
	corrupt = 1;

	if (update_dotdot) {
		int start = MSDOS_I(old_dir)->i_logstart;
		dotdot_de->start = cpu_to_le16(start);
		dotdot_de->starthi = cpu_to_le16(start >> 16);
		mark_buffer_dirty_inode(dotdot_bh, old_inode);
		corrupt |= sync_dirty_buffer(dotdot_bh);
	}
error_inode:
	fat_detach(old_inode);
	fat_attach(old_inode, old_sinfo.i_pos);
	MSDOS_I(old_inode)->i_attrs = old_attrs;
	if (new_inode) {
		fat_attach(new_inode, new_i_pos);
		if (corrupt)
			corrupt |= fat_sync_inode(new_inode);
	} else {
		/*
		 * If new entry was not sharing the data cluster, it
		 * shouldn't be serious corruption.
		 */
		int err2 = fat_remove_entries(new_dir, &sinfo);
		if (corrupt)
			corrupt |= err2;
		sinfo.bh = NULL;
	}
	if (corrupt < 0) {
		fat_fs_error(new_dir->i_sb,
			     "%s: Filesystem corrupted (i_pos %lld)",
			     __func__, sinfo.i_pos);
	}
	goto out;
}

/***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
static int msdos_rename(struct inode *old_dir, struct dentry *old_dentry,
			struct inode *new_dir, struct dentry *new_dentry)
{
	struct super_block *sb = old_dir->i_sb;
	unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
	int err, is_hid;

	lock_super(sb);

	err = msdos_format_name(old_dentry->d_name.name,
				old_dentry->d_name.len, old_msdos_name,
				&MSDOS_SB(old_dir->i_sb)->options);
	if (err)
		goto out;
	err = msdos_format_name(new_dentry->d_name.name,
				new_dentry->d_name.len, new_msdos_name,
				&MSDOS_SB(new_dir->i_sb)->options);
	if (err)
		goto out;

	is_hid =
	     (new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');

	err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
			      new_dir, new_msdos_name, new_dentry, is_hid);
out:
	unlock_super(sb);
	if (!err)
		err = fat_flush_inodes(sb, old_dir, new_dir);
	return err;
}

static const struct inode_operations msdos_dir_inode_operations = {
	.create		= msdos_create,
	.lookup		= msdos_lookup,
	.unlink		= msdos_unlink,
	.mkdir		= msdos_mkdir,
	.rmdir		= msdos_rmdir,
	.rename		= msdos_rename,
	.setattr	= fat_setattr,
	.getattr	= fat_getattr,
};

static int msdos_fill_super(struct super_block *sb, void *data, int silent)
{
	int res;

	lock_super(sb);
	res = fat_fill_super(sb, data, silent, &msdos_dir_inode_operations, 0);
	if (res) {
		unlock_super(sb);
		return res;
	}

	sb->s_flags |= MS_NOATIME;
	sb->s_root->d_op = &msdos_dentry_operations;
	unlock_super(sb);
	return 0;
}

static struct dentry *msdos_mount(struct file_system_type *fs_type,
			int flags, const char *dev_name,
			void *data)
{
	return mount_bdev(fs_type, flags, dev_name, data, msdos_fill_super);
}

static struct file_system_type msdos_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "msdos",
	.mount		= msdos_mount,
	.kill_sb	= kill_block_super,
	.fs_flags	= FS_REQUIRES_DEV,
};

static int __init init_msdos_fs(void)
{
	return register_filesystem(&msdos_fs_type);
}

static void __exit exit_msdos_fs(void)
{
	unregister_filesystem(&msdos_fs_type);
}

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Werner Almesberger");
MODULE_DESCRIPTION("MS-DOS filesystem support");

module_init(init_msdos_fs)
module_exit(exit_msdos_fs)
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/msdos/namei.c
	3	*
	4	* Written 1992,1993 by Werner Almesberger
	5	* Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu>
	6	* Rewritten for constant inumbers 1999 by Al Viro
	7	*/
	8
	9	#include <linux/module.h>
	10	#include <linux/time.h>
	11	#include <linux/buffer_head.h>
9e975dae	12	#include "fat.h"
1da177e4	13
1da177e4 LT	14	/* Characters that are undesirable in an MS-DOS file name */
1da177e4 LT	15	static unsigned char bad_chars[] = "*?<>\|\"";
7557bc66	16	static unsigned char bad_if_strict[] = "+=,; ";
1da177e4 LT	17
	18	/***** Formats an MS-DOS file name. Rejects invalid names. */
	19	static int msdos_format_name(const unsigned char *name, int len,
	20	unsigned char res, struct fat_mount_options opts)
	21	/*
	22	* name is the proposed name, len is its length, res is
	23	* the resulting name, opts->name_check is either (r)elaxed,
	24	* (n)ormal or (s)trict, opts->dotsOK allows dots at the
	25	* beginning of name (for hidden files)
	26	*/
	27	{
	28	unsigned char *walk;
1da177e4 LT	29	unsigned char c;
	30	int space;
	31
	32	if (name[0] == '.') { /* dotfile because . and .. already done */
	33	if (opts->dotsOK) {
	34	/* Get rid of dot - test for it elsewhere */
	35	name++;
	36	len--;
7557bc66	37	} else
1da177e4 LT	38	return -EINVAL;
	39	}
	40	/*
7557bc66	41	* disallow names that _really_ start with a dot
1da177e4	42	*/
7557bc66	43	space = 1;
1da177e4 LT	44	c = 0;
	45	for (walk = res; len && walk - res < 8; walk++) {
	46	c = *name++;
	47	len--;
	48	if (opts->name_check != 'r' && strchr(bad_chars, c))
	49	return -EINVAL;
7557bc66	50	if (opts->name_check == 's' && strchr(bad_if_strict, c))
1da177e4 LT	51	return -EINVAL;
	52	if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
	53	return -EINVAL;
	54	if (c < ' ' \|\| c == ':' \|\| c == '\\')
	55	return -EINVAL;
	56	/*
	57	* 0xE5 is legal as a first character, but we must substitute
	58	* 0x05 because 0xE5 marks deleted files. Yes, DOS really
	59	* does this.
	60	* It seems that Microsoft hacked DOS to support non-US
	61	* characters after the 0xE5 character was already in use to
	62	* mark deleted files.
	63	*/
	64	if ((res == walk) && (c == 0xE5))
	65	c = 0x05;
	66	if (c == '.')
	67	break;
	68	space = (c == ' ');
	69	*walk = (!opts->nocase && c >= 'a' && c <= 'z') ? c - 32 : c;
	70	}
	71	if (space)
	72	return -EINVAL;
	73	if (opts->name_check == 's' && len && c != '.') {
	74	c = *name++;
	75	len--;
	76	if (c != '.')
	77	return -EINVAL;
	78	}
	79	while (c != '.' && len--)
	80	c = *name++;
	81	if (c == '.') {
	82	while (walk - res < 8)
	83	*walk++ = ' ';
	84	while (len > 0 && walk - res < MSDOS_NAME) {
	85	c = *name++;
	86	len--;
	87	if (opts->name_check != 'r' && strchr(bad_chars, c))
	88	return -EINVAL;
	89	if (opts->name_check == 's' &&
7557bc66	90	strchr(bad_if_strict, c))
1da177e4 LT	91	return -EINVAL;
	92	if (c < ' ' \|\| c == ':' \|\| c == '\\')
	93	return -EINVAL;
	94	if (c == '.') {
	95	if (opts->name_check == 's')
	96	return -EINVAL;
	97	break;
	98	}
	99	if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
	100	return -EINVAL;
	101	space = c == ' ';
	102	if (!opts->nocase && c >= 'a' && c <= 'z')
	103	*walk++ = c - 32;
	104	else
	105	*walk++ = c;
	106	}
	107	if (space)
	108	return -EINVAL;
	109	if (opts->name_check == 's' && len)
	110	return -EINVAL;
	111	}
	112	while (walk - res < MSDOS_NAME)
	113	*walk++ = ' ';
094e320d	114
1da177e4 LT	115	return 0;
	116	}
	117
	118	/***** Locates a directory entry. Uses unformatted name. */
	119	static int msdos_find(struct inode dir, const unsigned char name, int len,
	120	struct fat_slot_info *sinfo)
	121	{
	122	struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
	123	unsigned char msdos_name[MSDOS_NAME];
	124	int err;
	125
	126	err = msdos_format_name(name, len, msdos_name, &sbi->options);
	127	if (err)
	128	return -ENOENT;
	129
	130	err = fat_scan(dir, msdos_name, sinfo);
	131	if (!err && sbi->options.dotsOK) {
	132	if (name[0] == '.') {
	133	if (!(sinfo->de->attr & ATTR_HIDDEN))
	134	err = -ENOENT;
	135	} else {
	136	if (sinfo->de->attr & ATTR_HIDDEN)
	137	err = -ENOENT;
	138	}
	139	if (err)
	140	brelse(sinfo->bh);
	141	}
	142	return err;
	143	}
	144
	145	/*
	146	* Compute the hash for the msdos name corresponding to the dentry.
	147	* Note: if the name is invalid, we leave the hash code unchanged so
	148	* that the existing dentry can be used. The msdos fs routines will
	149	* return ENOENT or EINVAL as appropriate.
	150	*/
	151	static int msdos_hash(struct dentry dentry, struct qstr qstr)
	152	{
	153	struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
	154	unsigned char msdos_name[MSDOS_NAME];
	155	int error;
	156
	157	error = msdos_format_name(qstr->name, qstr->len, msdos_name, options);
	158	if (!error)
	159	qstr->hash = full_name_hash(msdos_name, MSDOS_NAME);
	160	return 0;
	161	}
	162
	163	/*
	164	* Compare two msdos names. If either of the names are invalid,
	165	* we fall back to doing the standard name comparison.
	166	*/
	167	static int msdos_cmp(struct dentry dentry, struct qstr a, struct qstr *b)
	168	{
	169	struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
	170	unsigned char a_msdos_name[MSDOS_NAME], b_msdos_name[MSDOS_NAME];
	171	int error;
	172
	173	error = msdos_format_name(a->name, a->len, a_msdos_name, options);
	174	if (error)
	175	goto old_compare;
	176	error = msdos_format_name(b->name, b->len, b_msdos_name, options);
	177	if (error)
	178	goto old_compare;
179	error = memcmp(a_msdos_name, b_msdos_name, MSDOS_NAME);
180	out:
181	return error;
182
183	old_compare:
184	error = 1;
185	if (a->len == b->len)
186	error = memcmp(a->name, b->name, a->len);
187	goto out;
188	}
189
ce6cdc47	190	static const struct dentry_operations msdos_dentry_operations = {
1da177e4 LT	191	.d_hash = msdos_hash,
	192	.d_compare = msdos_cmp,
	193	};
	194
	195	/*
	196	* AV. Wrappers for FAT sb operations. Is it wise?
	197	*/
	198
	199	/***** Get inode using directory and name */
	200	static struct dentry msdos_lookup(struct inode dir, struct dentry *dentry,
	201	struct nameidata *nd)
	202	{
	203	struct super_block *sb = dir->i_sb;
	204	struct fat_slot_info sinfo;
45cfbe35 OH	205	struct inode *inode;
45cfbe35 OH	206	int err;
1da177e4	207
8f593427	208	lock_super(sb);
45cfbe35 OH	209
	210	err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
	211	if (err) {
	212	if (err == -ENOENT) {
	213	inode = NULL;
	214	goto out;
	215	}
	216	goto error;
	217	}
	218
1da177e4 LT	219	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
	220	brelse(sinfo.bh);
	221	if (IS_ERR(inode)) {
45cfbe35 OH	222	err = PTR_ERR(inode);
45cfbe35 OH	223	goto error;
1da177e4	224	}
45cfbe35 OH	225	out:
	226	unlock_super(sb);
	227	dentry->d_op = &msdos_dentry_operations;
1da177e4 LT	228	dentry = d_splice_alias(inode, dentry);
	229	if (dentry)
	230	dentry->d_op = &msdos_dentry_operations;
45cfbe35 OH	231	return dentry;
	232
	233	error:
8f593427	234	unlock_super(sb);
45cfbe35	235	return ERR_PTR(err);
1da177e4 LT	236	}
	237
	238	/***** Creates a directory entry (name is already formatted). */
	239	static int msdos_add_entry(struct inode dir, const unsigned char name,
	240	int is_dir, int is_hid, int cluster,
	241	struct timespec ts, struct fat_slot_info sinfo)
	242	{
b271e067	243	struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
1da177e4 LT	244	struct msdos_dir_entry de;
	245	__le16 time, date;
	246	int err;
	247
	248	memcpy(de.name, name, MSDOS_NAME);
	249	de.attr = is_dir ? ATTR_DIR : ATTR_ARCH;
	250	if (is_hid)
	251	de.attr \|= ATTR_HIDDEN;
	252	de.lcase = 0;
7decd1cb	253	fat_time_unix2fat(sbi, ts, &time, &date, NULL);
1da177e4 LT	254	de.cdate = de.adate = 0;
	255	de.ctime = 0;
	256	de.ctime_cs = 0;
	257	de.time = time;
	258	de.date = date;
	259	de.start = cpu_to_le16(cluster);
	260	de.starthi = cpu_to_le16(cluster >> 16);
	261	de.size = 0;
	262
	263	err = fat_add_entries(dir, &de, 1, sinfo);
	264	if (err)
	265	return err;
	266
	267	dir->i_ctime = dir->i_mtime = *ts;
	268	if (IS_DIRSYNC(dir))
	269	(void)fat_sync_inode(dir);
	270	else
	271	mark_inode_dirty(dir);
	272
	273	return 0;
	274	}
	275
	276	/***** Create a file */
	277	static int msdos_create(struct inode dir, struct dentry dentry, int mode,
	278	struct nameidata *nd)
	279	{
	280	struct super_block *sb = dir->i_sb;
ae78bf9c	281	struct inode *inode = NULL;
1da177e4 LT	282	struct fat_slot_info sinfo;
	283	struct timespec ts;
	284	unsigned char msdos_name[MSDOS_NAME];
	285	int err, is_hid;
	286
8f593427	287	lock_super(sb);
1da177e4 LT	288
	289	err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
	290	msdos_name, &MSDOS_SB(sb)->options);
	291	if (err)
	292	goto out;
	293	is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
	294	/* Have to do it due to foo vs. .foo conflicts */
	295	if (!fat_scan(dir, msdos_name, &sinfo)) {
	296	brelse(sinfo.bh);
	297	err = -EINVAL;
	298	goto out;
	299	}
	300
	301	ts = CURRENT_TIME_SEC;
	302	err = msdos_add_entry(dir, msdos_name, 0, is_hid, 0, &ts, &sinfo);
	303	if (err)
	304	goto out;
	305	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
	306	brelse(sinfo.bh);
	307	if (IS_ERR(inode)) {
	308	err = PTR_ERR(inode);
	309	goto out;
	310	}
	311	inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
	312	/* timestamp is already written, so mark_inode_dirty() is unneeded. */
	313
	314	d_instantiate(dentry, inode);
	315	out:
8f593427	316	unlock_super(sb);
ae78bf9c CM	317	if (!err)
ae78bf9c CM	318	err = fat_flush_inodes(sb, dir, inode);
1da177e4 LT	319	return err;
	320	}
	321
	322	/***** Remove a directory */
	323	static int msdos_rmdir(struct inode dir, struct dentry dentry)
	324	{
8f593427	325	struct super_block *sb = dir->i_sb;
1da177e4 LT	326	struct inode *inode = dentry->d_inode;
	327	struct fat_slot_info sinfo;
	328	int err;
	329
8f593427	330	lock_super(sb);
1da177e4 LT	331	/*
	332	* Check whether the directory is not in use, then check
	333	* whether it is empty.
	334	*/
	335	err = fat_dir_empty(inode);
	336	if (err)
	337	goto out;
	338	err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
	339	if (err)
	340	goto out;
	341
	342	err = fat_remove_entries(dir, &sinfo); /* and releases bh */
	343	if (err)
	344	goto out;
9a53c3a7	345	drop_nlink(dir);
1da177e4	346
ce71ec36	347	clear_nlink(inode);
1da177e4 LT	348	inode->i_ctime = CURRENT_TIME_SEC;
	349	fat_detach(inode);
	350	out:
8f593427	351	unlock_super(sb);
ae78bf9c	352	if (!err)
8f593427	353	err = fat_flush_inodes(sb, dir, inode);
1da177e4 LT	354
	355	return err;
	356	}
	357
	358	/***** Make a directory */
	359	static int msdos_mkdir(struct inode dir, struct dentry dentry, int mode)
	360	{
	361	struct super_block *sb = dir->i_sb;
	362	struct fat_slot_info sinfo;
	363	struct inode *inode;
	364	unsigned char msdos_name[MSDOS_NAME];
	365	struct timespec ts;
	366	int err, is_hid, cluster;
	367
8f593427	368	lock_super(sb);
1da177e4 LT	369
	370	err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
	371	msdos_name, &MSDOS_SB(sb)->options);
	372	if (err)
	373	goto out;
	374	is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
	375	/* foo vs .foo situation */
	376	if (!fat_scan(dir, msdos_name, &sinfo)) {
	377	brelse(sinfo.bh);
	378	err = -EINVAL;
	379	goto out;
	380	}
	381
	382	ts = CURRENT_TIME_SEC;
	383	cluster = fat_alloc_new_dir(dir, &ts);
	384	if (cluster < 0) {
	385	err = cluster;
	386	goto out;
	387	}
	388	err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
	389	if (err)
	390	goto out_free;
d8c76e6f	391	inc_nlink(dir);
1da177e4 LT	392
	393	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
	394	brelse(sinfo.bh);
	395	if (IS_ERR(inode)) {
	396	err = PTR_ERR(inode);
	397	/* the directory was completed, just return a error */
	398	goto out;
	399	}
	400	inode->i_nlink = 2;
	401	inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
	402	/* timestamp is already written, so mark_inode_dirty() is unneeded. */
	403
	404	d_instantiate(dentry, inode);
	405
8f593427	406	unlock_super(sb);
ae78bf9c	407	fat_flush_inodes(sb, dir, inode);
1da177e4 LT	408	return 0;
	409
	410	out_free:
	411	fat_free_clusters(dir, cluster);
	412	out:
8f593427	413	unlock_super(sb);
1da177e4 LT	414	return err;
	415	}
	416
	417	/***** Unlink a file */
	418	static int msdos_unlink(struct inode dir, struct dentry dentry)
	419	{
	420	struct inode *inode = dentry->d_inode;
8f593427	421	struct super_block *sb= inode->i_sb;
1da177e4 LT	422	struct fat_slot_info sinfo;
	423	int err;
	424
8f593427	425	lock_super(sb);
1da177e4 LT	426	err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
	427	if (err)
	428	goto out;
	429
	430	err = fat_remove_entries(dir, &sinfo); /* and releases bh */
	431	if (err)
	432	goto out;
ce71ec36	433	clear_nlink(inode);
1da177e4 LT	434	inode->i_ctime = CURRENT_TIME_SEC;
	435	fat_detach(inode);
	436	out:
8f593427	437	unlock_super(sb);
ae78bf9c	438	if (!err)
8f593427	439	err = fat_flush_inodes(sb, dir, inode);
1da177e4 LT	440
	441	return err;
	442	}
	443
	444	static int do_msdos_rename(struct inode old_dir, unsigned char old_name,
	445	struct dentry *old_dentry,
	446	struct inode new_dir, unsigned char new_name,
	447	struct dentry *new_dentry, int is_hid)
	448	{
	449	struct buffer_head *dotdot_bh;
	450	struct msdos_dir_entry *dotdot_de;
1da177e4 LT	451	struct inode old_inode, new_inode;
	452	struct fat_slot_info old_sinfo, sinfo;
	453	struct timespec ts;
9131dd42	454	loff_t dotdot_i_pos, new_i_pos;
1da177e4 LT	455	int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
	456
	457	old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
	458	old_inode = old_dentry->d_inode;
	459	new_inode = new_dentry->d_inode;
	460
	461	err = fat_scan(old_dir, old_name, &old_sinfo);
	462	if (err) {
	463	err = -EIO;
	464	goto out;
	465	}
	466
	467	is_dir = S_ISDIR(old_inode->i_mode);
	468	update_dotdot = (is_dir && old_dir != new_dir);
	469	if (update_dotdot) {
	470	if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de,
	471	&dotdot_i_pos) < 0) {
	472	err = -EIO;
	473	goto out;
	474	}
	475	}
	476
	477	old_attrs = MSDOS_I(old_inode)->i_attrs;
	478	err = fat_scan(new_dir, new_name, &sinfo);
	479	if (!err) {
	480	if (!new_inode) {
	481	/* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
	482	if (sinfo.de != old_sinfo.de) {
	483	err = -EINVAL;
	484	goto out;
	485	}
	486	if (is_hid)
	487	MSDOS_I(old_inode)->i_attrs \|= ATTR_HIDDEN;
	488	else
	489	MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
	490	if (IS_DIRSYNC(old_dir)) {
	491	err = fat_sync_inode(old_inode);
	492	if (err) {
	493	MSDOS_I(old_inode)->i_attrs = old_attrs;
	494	goto out;
	495	}
	496	} else
	497	mark_inode_dirty(old_inode);
	498
	499	old_dir->i_version++;
	500	old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
	501	if (IS_DIRSYNC(old_dir))
	502	(void)fat_sync_inode(old_dir);
	503	else
	504	mark_inode_dirty(old_dir);
	505	goto out;
	506	}
	507	}
	508
	509	ts = CURRENT_TIME_SEC;
	510	if (new_inode) {
	511	if (err)
	512	goto out;
1da177e4 LT	513	if (is_dir) {
	514	err = fat_dir_empty(new_inode);
	515	if (err)
	516	goto out;
	517	}
9131dd42	518	new_i_pos = MSDOS_I(new_inode)->i_pos;
1da177e4 LT	519	fat_detach(new_inode);
	520	} else {
	521	err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
	522	&ts, &sinfo);
	523	if (err)
	524	goto out;
9131dd42	525	new_i_pos = sinfo.i_pos;
1da177e4 LT	526	}
	527	new_dir->i_version++;
	528
	529	fat_detach(old_inode);
9131dd42	530	fat_attach(old_inode, new_i_pos);
1da177e4 LT	531	if (is_hid)
	532	MSDOS_I(old_inode)->i_attrs \|= ATTR_HIDDEN;
	533	else
	534	MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
	535	if (IS_DIRSYNC(new_dir)) {
	536	err = fat_sync_inode(old_inode);
	537	if (err)
	538	goto error_inode;
	539	} else
	540	mark_inode_dirty(old_inode);
	541
	542	if (update_dotdot) {
	543	int start = MSDOS_I(new_dir)->i_logstart;
	544	dotdot_de->start = cpu_to_le16(start);
	545	dotdot_de->starthi = cpu_to_le16(start >> 16);
b522412a	546	mark_buffer_dirty_inode(dotdot_bh, old_inode);
1da177e4 LT	547	if (IS_DIRSYNC(new_dir)) {
	548	err = sync_dirty_buffer(dotdot_bh);
	549	if (err)
	550	goto error_dotdot;
	551	}
9a53c3a7	552	drop_nlink(old_dir);
1da177e4	553	if (!new_inode)
d8c76e6f	554	inc_nlink(new_dir);
1da177e4 LT	555	}
	556
	557	err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */
	558	old_sinfo.bh = NULL;
	559	if (err)
	560	goto error_dotdot;
	561	old_dir->i_version++;
	562	old_dir->i_ctime = old_dir->i_mtime = ts;
	563	if (IS_DIRSYNC(old_dir))
	564	(void)fat_sync_inode(old_dir);
	565	else
	566	mark_inode_dirty(old_dir);
	567
	568	if (new_inode) {
9a53c3a7	569	drop_nlink(new_inode);
1da177e4	570	if (is_dir)
9a53c3a7	571	drop_nlink(new_inode);
1da177e4 LT	572	new_inode->i_ctime = ts;
	573	}
	574	out:
	575	brelse(sinfo.bh);
	576	brelse(dotdot_bh);
	577	brelse(old_sinfo.bh);
	578	return err;
	579
	580	error_dotdot:
	581	/* data cluster is shared, serious corruption */
	582	corrupt = 1;
	583
	584	if (update_dotdot) {
	585	int start = MSDOS_I(old_dir)->i_logstart;
	586	dotdot_de->start = cpu_to_le16(start);
	587	dotdot_de->starthi = cpu_to_le16(start >> 16);
b522412a	588	mark_buffer_dirty_inode(dotdot_bh, old_inode);
1da177e4 LT	589	corrupt \|= sync_dirty_buffer(dotdot_bh);
	590	}
	591	error_inode:
	592	fat_detach(old_inode);
	593	fat_attach(old_inode, old_sinfo.i_pos);
	594	MSDOS_I(old_inode)->i_attrs = old_attrs;
	595	if (new_inode) {
9131dd42	596	fat_attach(new_inode, new_i_pos);
1da177e4 LT	597	if (corrupt)
	598	corrupt \|= fat_sync_inode(new_inode);
	599	} else {
	600	/*
	601	* If new entry was not sharing the data cluster, it
	602	* shouldn't be serious corruption.
	603	*/
	604	int err2 = fat_remove_entries(new_dir, &sinfo);
	605	if (corrupt)
	606	corrupt \|= err2;
	607	sinfo.bh = NULL;
	608	}
	609	if (corrupt < 0) {
85c78591	610	fat_fs_error(new_dir->i_sb,
1da177e4	611	"%s: Filesystem corrupted (i_pos %lld)",
8e24eea7	612	__func__, sinfo.i_pos);
1da177e4 LT	613	}
	614	goto out;
	615	}
	616
	617	/***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
	618	static int msdos_rename(struct inode old_dir, struct dentry old_dentry,
	619	struct inode new_dir, struct dentry new_dentry)
	620	{
8f593427	621	struct super_block *sb = old_dir->i_sb;
1da177e4 LT	622	unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
	623	int err, is_hid;
	624
8f593427	625	lock_super(sb);
1da177e4 LT	626
	627	err = msdos_format_name(old_dentry->d_name.name,
	628	old_dentry->d_name.len, old_msdos_name,
	629	&MSDOS_SB(old_dir->i_sb)->options);
	630	if (err)
	631	goto out;
	632	err = msdos_format_name(new_dentry->d_name.name,
	633	new_dentry->d_name.len, new_msdos_name,
	634	&MSDOS_SB(new_dir->i_sb)->options);
	635	if (err)
	636	goto out;
	637
	638	is_hid =
	639	(new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');
	640
	641	err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
	642	new_dir, new_msdos_name, new_dentry, is_hid);
	643	out:
8f593427	644	unlock_super(sb);
ae78bf9c	645	if (!err)
8f593427	646	err = fat_flush_inodes(sb, old_dir, new_dir);
1da177e4 LT	647	return err;
	648	}
	649
92e1d5be	650	static const struct inode_operations msdos_dir_inode_operations = {
1da177e4 LT	651	.create = msdos_create,
	652	.lookup = msdos_lookup,
	653	.unlink = msdos_unlink,
	654	.mkdir = msdos_mkdir,
	655	.rmdir = msdos_rmdir,
	656	.rename = msdos_rename,
1278fdd3	657	.setattr = fat_setattr,
da63fc7c	658	.getattr = fat_getattr,
1da177e4 LT	659	};
	660
	661	static int msdos_fill_super(struct super_block sb, void data, int silent)
	662	{
	663	int res;
	664
3768744c	665	lock_super(sb);
1da177e4	666	res = fat_fill_super(sb, data, silent, &msdos_dir_inode_operations, 0);
db719222	667	if (res) {
3768744c	668	unlock_super(sb);
1da177e4	669	return res;
db719222	670	}
1da177e4 LT	671
	672	sb->s_flags \|= MS_NOATIME;
	673	sb->s_root->d_op = &msdos_dentry_operations;
3768744c	674	unlock_super(sb);
1da177e4 LT	675	return 0;
	676	}
	677
152a0836	678	static struct dentry msdos_mount(struct file_system_type fs_type,
454e2398	679	int flags, const char *dev_name,
152a0836	680	void *data)
1da177e4	681	{
152a0836	682	return mount_bdev(fs_type, flags, dev_name, data, msdos_fill_super);
1da177e4 LT	683	}
	684
	685	static struct file_system_type msdos_fs_type = {
	686	.owner = THIS_MODULE,
	687	.name = "msdos",
152a0836	688	.mount = msdos_mount,
1da177e4 LT	689	.kill_sb = kill_block_super,
	690	.fs_flags = FS_REQUIRES_DEV,
	691	};
	692
	693	static int __init init_msdos_fs(void)
	694	{
	695	return register_filesystem(&msdos_fs_type);
	696	}
	697
	698	static void __exit exit_msdos_fs(void)
	699	{
	700	unregister_filesystem(&msdos_fs_type);
	701	}
	702
	703	MODULE_LICENSE("GPL");
	704	MODULE_AUTHOR("Werner Almesberger");
	705	MODULE_DESCRIPTION("MS-DOS filesystem support");
	706
	707	module_init(init_msdos_fs)
	708	module_exit(exit_msdos_fs)