[net-next-2.6.git] / fs / msdos / namei.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 <linux/msdos_fs.h>
#include <linux/smp_lock.h>

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

#define bad_if_strict(opts) \
	((opts)->atari ? bad_if_strict_atari : bad_if_strict_pc)

/***** 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 if (!opts->atari)
			return -EINVAL;
	}
	/*
	 * disallow names that _really_ start with a dot for MS-DOS,
	 * GEMDOS does not care
	 */
	space = !opts->atari;
	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(opts), 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(opts), 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 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 = NULL;
	int res;

	dentry->d_op = &msdos_dentry_operations;

	lock_kernel();
	res = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
	if (res == -ENOENT)
		goto add;
	if (res < 0)
		goto out;
	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
	brelse(sinfo.bh);
	if (IS_ERR(inode)) {
		res = PTR_ERR(inode);
		goto out;
	}
add:
	res = 0;
	dentry = d_splice_alias(inode, dentry);
	if (dentry)
		dentry->d_op = &msdos_dentry_operations;
out:
	unlock_kernel();
	if (!res)
		return dentry;
	return ERR_PTR(res);
}

/***** 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_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_date_unix2dos(ts->tv_sec, &time, &date);
	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_kernel();

	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_kernel();
	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 inode *inode = dentry->d_inode;
	struct fat_slot_info sinfo;
	int err;

	lock_kernel();
	/*
	 * 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_kernel();
	if (!err)
		err = fat_flush_inodes(inode->i_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_kernel();

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

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

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

	lock_kernel();
	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_kernel();
	if (!err)
		err = fat_flush_inodes(inode->i_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(dotdot_bh);
		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(dotdot_bh);
		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_panic(new_dir->i_sb,
			     "%s: Filesystem corrupted (i_pos %lld)",
			     __FUNCTION__, 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)
{
	unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
	int err, is_hid;

	lock_kernel();

	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_kernel();
	if (!err)
		err = fat_flush_inodes(old_dir->i_sb, old_dir, new_dir);
	return err;
}

static 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_notify_change,
};

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

	res = fat_fill_super(sb, data, silent, &msdos_dir_inode_operations, 0);
	if (res)
		return res;

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

static int msdos_get_sb(struct file_system_type *fs_type,
			int flags, const char *dev_name,
			void *data, struct vfsmount *mnt)
{
	return get_sb_bdev(fs_type, flags, dev_name, data, msdos_fill_super,
			   mnt);
}

static struct file_system_type msdos_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "msdos",
	.get_sb		= msdos_get_sb,
	.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>
	12	#include <linux/msdos_fs.h>
	13	#include <linux/smp_lock.h>
	14
1da177e4 LT	15	/* Characters that are undesirable in an MS-DOS file name */
	16	static unsigned char bad_chars[] = "*?<>\|\"";
	17	static unsigned char bad_if_strict_pc[] = "+=,; ";
	18	/* GEMDOS is less restrictive */
	19	static unsigned char bad_if_strict_atari[] = " ";
	20
	21	#define bad_if_strict(opts) \
	22	((opts)->atari ? bad_if_strict_atari : bad_if_strict_pc)
	23
	24	/***** Formats an MS-DOS file name. Rejects invalid names. */
	25	static int msdos_format_name(const unsigned char *name, int len,
	26	unsigned char res, struct fat_mount_options opts)
	27	/*
	28	* name is the proposed name, len is its length, res is
	29	* the resulting name, opts->name_check is either (r)elaxed,
	30	* (n)ormal or (s)trict, opts->dotsOK allows dots at the
	31	* beginning of name (for hidden files)
	32	*/
	33	{
	34	unsigned char *walk;
1da177e4 LT	35	unsigned char c;
	36	int space;
	37
	38	if (name[0] == '.') { /* dotfile because . and .. already done */
	39	if (opts->dotsOK) {
	40	/* Get rid of dot - test for it elsewhere */
	41	name++;
	42	len--;
	43	} else if (!opts->atari)
	44	return -EINVAL;
	45	}
	46	/*
	47	* disallow names that _really_ start with a dot for MS-DOS,
	48	* GEMDOS does not care
	49	*/
	50	space = !opts->atari;
	51	c = 0;
	52	for (walk = res; len && walk - res < 8; walk++) {
	53	c = *name++;
	54	len--;
	55	if (opts->name_check != 'r' && strchr(bad_chars, c))
	56	return -EINVAL;
	57	if (opts->name_check == 's' && strchr(bad_if_strict(opts), c))
	58	return -EINVAL;
	59	if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
	60	return -EINVAL;
	61	if (c < ' ' \|\| c == ':' \|\| c == '\\')
	62	return -EINVAL;
	63	/*
	64	* 0xE5 is legal as a first character, but we must substitute
	65	* 0x05 because 0xE5 marks deleted files. Yes, DOS really
	66	* does this.
	67	* It seems that Microsoft hacked DOS to support non-US
	68	* characters after the 0xE5 character was already in use to
	69	* mark deleted files.
	70	*/
	71	if ((res == walk) && (c == 0xE5))
	72	c = 0x05;
	73	if (c == '.')
	74	break;
	75	space = (c == ' ');
	76	*walk = (!opts->nocase && c >= 'a' && c <= 'z') ? c - 32 : c;
	77	}
	78	if (space)
	79	return -EINVAL;
	80	if (opts->name_check == 's' && len && c != '.') {
	81	c = *name++;
	82	len--;
	83	if (c != '.')
	84	return -EINVAL;
	85	}
	86	while (c != '.' && len--)
	87	c = *name++;
	88	if (c == '.') {
	89	while (walk - res < 8)
	90	*walk++ = ' ';
	91	while (len > 0 && walk - res < MSDOS_NAME) {
	92	c = *name++;
	93	len--;
	94	if (opts->name_check != 'r' && strchr(bad_chars, c))
	95	return -EINVAL;
	96	if (opts->name_check == 's' &&
	97	strchr(bad_if_strict(opts), c))
	98	return -EINVAL;
99	if (c < ' ' \|\| c == ':' \|\| c == '\\')
100	return -EINVAL;
101	if (c == '.') {
102	if (opts->name_check == 's')
103	return -EINVAL;
104	break;
105	}
106	if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
107	return -EINVAL;
108	space = c == ' ';
109	if (!opts->nocase && c >= 'a' && c <= 'z')
110	*walk++ = c - 32;
111	else
112	*walk++ = c;
113	}
114	if (space)
115	return -EINVAL;
116	if (opts->name_check == 's' && len)
117	return -EINVAL;
118	}
119	while (walk - res < MSDOS_NAME)
120	*walk++ = ' ';
094e320d	121
1da177e4 LT	122	return 0;
	123	}
	124
	125	/***** Locates a directory entry. Uses unformatted name. */
	126	static int msdos_find(struct inode dir, const unsigned char name, int len,
	127	struct fat_slot_info *sinfo)
	128	{
	129	struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
	130	unsigned char msdos_name[MSDOS_NAME];
	131	int err;
	132
	133	err = msdos_format_name(name, len, msdos_name, &sbi->options);
	134	if (err)
	135	return -ENOENT;
	136
	137	err = fat_scan(dir, msdos_name, sinfo);
	138	if (!err && sbi->options.dotsOK) {
	139	if (name[0] == '.') {
	140	if (!(sinfo->de->attr & ATTR_HIDDEN))
	141	err = -ENOENT;
	142	} else {
	143	if (sinfo->de->attr & ATTR_HIDDEN)
	144	err = -ENOENT;
	145	}
	146	if (err)
	147	brelse(sinfo->bh);
	148	}
	149	return err;
	150	}
	151
	152	/*
	153	* Compute the hash for the msdos name corresponding to the dentry.
	154	* Note: if the name is invalid, we leave the hash code unchanged so
	155	* that the existing dentry can be used. The msdos fs routines will
	156	* return ENOENT or EINVAL as appropriate.
	157	*/
	158	static int msdos_hash(struct dentry dentry, struct qstr qstr)
	159	{
	160	struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
	161	unsigned char msdos_name[MSDOS_NAME];
	162	int error;
	163
	164	error = msdos_format_name(qstr->name, qstr->len, msdos_name, options);
	165	if (!error)
	166	qstr->hash = full_name_hash(msdos_name, MSDOS_NAME);
	167	return 0;
	168	}
	169
	170	/*
	171	* Compare two msdos names. If either of the names are invalid,
	172	* we fall back to doing the standard name comparison.
	173	*/
	174	static int msdos_cmp(struct dentry dentry, struct qstr a, struct qstr *b)
	175	{
	176	struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
	177	unsigned char a_msdos_name[MSDOS_NAME], b_msdos_name[MSDOS_NAME];
	178	int error;
	179
	180	error = msdos_format_name(a->name, a->len, a_msdos_name, options);
	181	if (error)
	182	goto old_compare;
	183	error = msdos_format_name(b->name, b->len, b_msdos_name, options);
	184	if (error)
	185	goto old_compare;
186	error = memcmp(a_msdos_name, b_msdos_name, MSDOS_NAME);
187	out:
188	return error;
189
190	old_compare:
191	error = 1;
192	if (a->len == b->len)
193	error = memcmp(a->name, b->name, a->len);
194	goto out;
195	}
196
197	static struct dentry_operations msdos_dentry_operations = {
198	.d_hash = msdos_hash,
199	.d_compare = msdos_cmp,
200	};
201
202	/*
203	* AV. Wrappers for FAT sb operations. Is it wise?
204	*/
205
206	/***** Get inode using directory and name */
207	static struct dentry msdos_lookup(struct inode dir, struct dentry *dentry,
208	struct nameidata *nd)
209	{
210	struct super_block *sb = dir->i_sb;
211	struct fat_slot_info sinfo;
212	struct inode *inode = NULL;
213	int res;
214
215	dentry->d_op = &msdos_dentry_operations;
216
217	lock_kernel();
218	res = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
219	if (res == -ENOENT)
220	goto add;
221	if (res < 0)
222	goto out;
223	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
224	brelse(sinfo.bh);
225	if (IS_ERR(inode)) {
226	res = PTR_ERR(inode);
227	goto out;
228	}
229	add:
230	res = 0;
231	dentry = d_splice_alias(inode, dentry);
232	if (dentry)
233	dentry->d_op = &msdos_dentry_operations;
234	out:
235	unlock_kernel();
236	if (!res)
237	return dentry;
238	return ERR_PTR(res);
239	}
240
241	/***** Creates a directory entry (name is already formatted). */
242	static int msdos_add_entry(struct inode dir, const unsigned char name,
243	int is_dir, int is_hid, int cluster,
244	struct timespec ts, struct fat_slot_info sinfo)
245	{
246	struct msdos_dir_entry de;
247	__le16 time, date;
248	int err;
249
250	memcpy(de.name, name, MSDOS_NAME);
251	de.attr = is_dir ? ATTR_DIR : ATTR_ARCH;
252	if (is_hid)
253	de.attr \|= ATTR_HIDDEN;
254	de.lcase = 0;
255	fat_date_unix2dos(ts->tv_sec, &time, &date);
256	de.cdate = de.adate = 0;
257	de.ctime = 0;
258	de.ctime_cs = 0;
259	de.time = time;
260	de.date = date;
261	de.start = cpu_to_le16(cluster);
262	de.starthi = cpu_to_le16(cluster >> 16);
263	de.size = 0;
264
265	err = fat_add_entries(dir, &de, 1, sinfo);
266	if (err)
267	return err;
268
269	dir->i_ctime = dir->i_mtime = *ts;
270	if (IS_DIRSYNC(dir))
271	(void)fat_sync_inode(dir);
272	else
273	mark_inode_dirty(dir);
274
275	return 0;
276	}
277
278	/***** Create a file */
279	static int msdos_create(struct inode dir, struct dentry dentry, int mode,
280	struct nameidata *nd)
281	{
282	struct super_block *sb = dir->i_sb;
ae78bf9c	283	struct inode *inode = NULL;
1da177e4 LT	284	struct fat_slot_info sinfo;
	285	struct timespec ts;
	286	unsigned char msdos_name[MSDOS_NAME];
	287	int err, is_hid;
	288
	289	lock_kernel();
	290
	291	err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
	292	msdos_name, &MSDOS_SB(sb)->options);
	293	if (err)
	294	goto out;
	295	is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
	296	/* Have to do it due to foo vs. .foo conflicts */
	297	if (!fat_scan(dir, msdos_name, &sinfo)) {
	298	brelse(sinfo.bh);
	299	err = -EINVAL;
	300	goto out;
	301	}
	302
	303	ts = CURRENT_TIME_SEC;
	304	err = msdos_add_entry(dir, msdos_name, 0, is_hid, 0, &ts, &sinfo);
	305	if (err)
	306	goto out;
	307	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
	308	brelse(sinfo.bh);
	309	if (IS_ERR(inode)) {
	310	err = PTR_ERR(inode);
	311	goto out;
	312	}
	313	inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
	314	/* timestamp is already written, so mark_inode_dirty() is unneeded. */
	315
	316	d_instantiate(dentry, inode);
	317	out:
	318	unlock_kernel();
ae78bf9c CM	319	if (!err)
ae78bf9c CM	320	err = fat_flush_inodes(sb, dir, inode);
1da177e4 LT	321	return err;
	322	}
	323
	324	/***** Remove a directory */
	325	static int msdos_rmdir(struct inode dir, struct dentry dentry)
	326	{
	327	struct inode *inode = dentry->d_inode;
	328	struct fat_slot_info sinfo;
	329	int err;
	330
	331	lock_kernel();
	332	/*
	333	* Check whether the directory is not in use, then check
	334	* whether it is empty.
	335	*/
	336	err = fat_dir_empty(inode);
	337	if (err)
	338	goto out;
	339	err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
	340	if (err)
	341	goto out;
	342
	343	err = fat_remove_entries(dir, &sinfo); /* and releases bh */
	344	if (err)
	345	goto out;
9a53c3a7	346	drop_nlink(dir);
1da177e4	347
ce71ec36	348	clear_nlink(inode);
1da177e4 LT	349	inode->i_ctime = CURRENT_TIME_SEC;
	350	fat_detach(inode);
	351	out:
	352	unlock_kernel();
ae78bf9c CM	353	if (!err)
ae78bf9c CM	354	err = fat_flush_inodes(inode->i_sb, dir, inode);
1da177e4 LT	355
	356	return err;
	357	}
	358
	359	/***** Make a directory */
	360	static int msdos_mkdir(struct inode dir, struct dentry dentry, int mode)
	361	{
	362	struct super_block *sb = dir->i_sb;
	363	struct fat_slot_info sinfo;
	364	struct inode *inode;
	365	unsigned char msdos_name[MSDOS_NAME];
	366	struct timespec ts;
	367	int err, is_hid, cluster;
	368
	369	lock_kernel();
	370
	371	err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
	372	msdos_name, &MSDOS_SB(sb)->options);
	373	if (err)
	374	goto out;
	375	is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
	376	/* foo vs .foo situation */
	377	if (!fat_scan(dir, msdos_name, &sinfo)) {
	378	brelse(sinfo.bh);
	379	err = -EINVAL;
	380	goto out;
	381	}
	382
	383	ts = CURRENT_TIME_SEC;
	384	cluster = fat_alloc_new_dir(dir, &ts);
	385	if (cluster < 0) {
	386	err = cluster;
	387	goto out;
	388	}
	389	err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
	390	if (err)
	391	goto out_free;
d8c76e6f	392	inc_nlink(dir);
1da177e4 LT	393
	394	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
	395	brelse(sinfo.bh);
	396	if (IS_ERR(inode)) {
	397	err = PTR_ERR(inode);
	398	/* the directory was completed, just return a error */
	399	goto out;
	400	}
	401	inode->i_nlink = 2;
	402	inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
	403	/* timestamp is already written, so mark_inode_dirty() is unneeded. */
	404
	405	d_instantiate(dentry, inode);
	406
	407	unlock_kernel();
ae78bf9c	408	fat_flush_inodes(sb, dir, inode);
1da177e4 LT	409	return 0;
	410
	411	out_free:
	412	fat_free_clusters(dir, cluster);
	413	out:
	414	unlock_kernel();
	415	return err;
	416	}
	417
	418	/***** Unlink a file */
	419	static int msdos_unlink(struct inode dir, struct dentry dentry)
	420	{
	421	struct inode *inode = dentry->d_inode;
	422	struct fat_slot_info sinfo;
	423	int err;
	424
	425	lock_kernel();
	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:
	437	unlock_kernel();
ae78bf9c CM	438	if (!err)
ae78bf9c CM	439	err = fat_flush_inodes(inode->i_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);
	546	mark_buffer_dirty(dotdot_bh);
	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);
	588	mark_buffer_dirty(dotdot_bh);
	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) {
	610	fat_fs_panic(new_dir->i_sb,
	611	"%s: Filesystem corrupted (i_pos %lld)",
	612	__FUNCTION__, sinfo.i_pos);
	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	{
	621	unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
	622	int err, is_hid;
	623
	624	lock_kernel();
	625
	626	err = msdos_format_name(old_dentry->d_name.name,
	627	old_dentry->d_name.len, old_msdos_name,
	628	&MSDOS_SB(old_dir->i_sb)->options);
	629	if (err)
	630	goto out;
	631	err = msdos_format_name(new_dentry->d_name.name,
	632	new_dentry->d_name.len, new_msdos_name,
	633	&MSDOS_SB(new_dir->i_sb)->options);
	634	if (err)
	635	goto out;
	636
	637	is_hid =
	638	(new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');
	639
	640	err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
	641	new_dir, new_msdos_name, new_dentry, is_hid);
	642	out:
	643	unlock_kernel();
ae78bf9c CM	644	if (!err)
ae78bf9c CM	645	err = fat_flush_inodes(old_dir->i_sb, old_dir, new_dir);
1da177e4 LT	646	return err;
	647	}
	648
	649	static struct inode_operations msdos_dir_inode_operations = {
	650	.create = msdos_create,
	651	.lookup = msdos_lookup,
	652	.unlink = msdos_unlink,
	653	.mkdir = msdos_mkdir,
	654	.rmdir = msdos_rmdir,
	655	.rename = msdos_rename,
	656	.setattr = fat_notify_change,
	657	};
	658
	659	static int msdos_fill_super(struct super_block sb, void data, int silent)
	660	{
	661	int res;
	662
	663	res = fat_fill_super(sb, data, silent, &msdos_dir_inode_operations, 0);
	664	if (res)
	665	return res;
	666
	667	sb->s_flags \|= MS_NOATIME;
	668	sb->s_root->d_op = &msdos_dentry_operations;
	669	return 0;
	670	}
	671
454e2398 DH	672	static int msdos_get_sb(struct file_system_type *fs_type,
	673	int flags, const char *dev_name,
	674	void data, struct vfsmount mnt)
1da177e4	675	{
454e2398 DH	676	return get_sb_bdev(fs_type, flags, dev_name, data, msdos_fill_super,
454e2398 DH	677	mnt);
1da177e4 LT	678	}
	679
	680	static struct file_system_type msdos_fs_type = {
	681	.owner = THIS_MODULE,
	682	.name = "msdos",
	683	.get_sb = msdos_get_sb,
	684	.kill_sb = kill_block_super,
	685	.fs_flags = FS_REQUIRES_DEV,
	686	};
	687
	688	static int __init init_msdos_fs(void)
	689	{
	690	return register_filesystem(&msdos_fs_type);
	691	}
	692
	693	static void __exit exit_msdos_fs(void)
	694	{
	695	unregister_filesystem(&msdos_fs_type);
	696	}
	697
	698	MODULE_LICENSE("GPL");
	699	MODULE_AUTHOR("Werner Almesberger");
	700	MODULE_DESCRIPTION("MS-DOS filesystem support");
	701
	702	module_init(init_msdos_fs)
	703	module_exit(exit_msdos_fs)