[linux-block.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(const struct dentry *dentry, const struct inode *inode,
	       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(const struct dentry *parent, const struct inode *pinode,
		const struct dentry *dentry, const struct inode *inode,
		unsigned int len, const char *str, const struct qstr *name)
{
	struct fat_mount_options *options = &MSDOS_SB(parent->d_sb)->options;
	unsigned char a_msdos_name[MSDOS_NAME], b_msdos_name[MSDOS_NAME];
	int error;

	error = msdos_format_name(name->name, name->len, a_msdos_name, options);
	if (error)
		goto old_compare;
	error = msdos_format_name(str, 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 (name->len == len)
		error = memcmp(name->name, str, 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,
				   unsigned int flags)
{
	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);
	switch (err) {
	case -ENOENT:
		inode = NULL;
		break;
	case 0:
		inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
		brelse(sinfo.bh);
		break;
	default:
		inode = ERR_PTR(err);
	}
	unlock_super(sb);
	return d_splice_alias(inode, dentry);
}

/***** 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;
	fat_set_start(&de, cluster);
	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, umode_t mode,
			bool excl)
{
	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, umode_t 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;
	}
	set_nlink(inode, 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 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)) {
			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) {
		fat_set_start(dotdot_de, MSDOS_I(new_dir)->i_logstart);
		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) {
		fat_set_start(dotdot_de, MSDOS_I(old_dir)->i_logstart);
		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 void setup(struct super_block *sb)
{
	MSDOS_SB(sb)->dir_ops = &msdos_dir_inode_operations;
	sb->s_d_op = &msdos_dentry_operations;
	sb->s_flags |= MS_NOATIME;
}

static int msdos_fill_super(struct super_block *sb, void *data, int silent)
{
	return fat_fill_super(sb, data, silent, 0, setup);
}

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	*/
b1e6a015 NP	151	static int msdos_hash(const struct dentry dentry, const struct inode inode,
b1e6a015 NP	152	struct qstr *qstr)
1da177e4 LT	153	{
	154	struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
	155	unsigned char msdos_name[MSDOS_NAME];
	156	int error;
	157
	158	error = msdos_format_name(qstr->name, qstr->len, msdos_name, options);
	159	if (!error)
	160	qstr->hash = full_name_hash(msdos_name, MSDOS_NAME);
	161	return 0;
	162	}
	163
	164	/*
	165	* Compare two msdos names. If either of the names are invalid,
	166	* we fall back to doing the standard name comparison.
	167	*/
621e155a NP	168	static int msdos_cmp(const struct dentry parent, const struct inode pinode,
	169	const struct dentry dentry, const struct inode inode,
	170	unsigned int len, const char str, const struct qstr name)
1da177e4	171	{
621e155a	172	struct fat_mount_options *options = &MSDOS_SB(parent->d_sb)->options;
1da177e4 LT	173	unsigned char a_msdos_name[MSDOS_NAME], b_msdos_name[MSDOS_NAME];
	174	int error;
	175
621e155a	176	error = msdos_format_name(name->name, name->len, a_msdos_name, options);
1da177e4 LT	177	if (error)
1da177e4 LT	178	goto old_compare;
621e155a	179	error = msdos_format_name(str, len, b_msdos_name, options);
1da177e4 LT	180	if (error)
	181	goto old_compare;
	182	error = memcmp(a_msdos_name, b_msdos_name, MSDOS_NAME);
	183	out:
	184	return error;
	185
	186	old_compare:
	187	error = 1;
621e155a NP	188	if (name->len == len)
621e155a NP	189	error = memcmp(name->name, str, len);
1da177e4 LT	190	goto out;
	191	}
	192
ce6cdc47	193	static const struct dentry_operations msdos_dentry_operations = {
1da177e4 LT	194	.d_hash = msdos_hash,
	195	.d_compare = msdos_cmp,
	196	};
	197
	198	/*
	199	* AV. Wrappers for FAT sb operations. Is it wise?
	200	*/
	201
	202	/***** Get inode using directory and name */
	203	static struct dentry msdos_lookup(struct inode dir, struct dentry *dentry,
00cd8dd3	204	unsigned int flags)
1da177e4 LT	205	{
	206	struct super_block *sb = dir->i_sb;
	207	struct fat_slot_info sinfo;
45cfbe35 OH	208	struct inode *inode;
45cfbe35 OH	209	int err;
1da177e4	210
8f593427	211	lock_super(sb);
45cfbe35	212	err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
a9049376 AV	213	switch (err) {
	214	case -ENOENT:
	215	inode = NULL;
	216	break;
	217	case 0:
	218	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
	219	brelse(sinfo.bh);
	220	break;
	221	default:
	222	inode = ERR_PTR(err);
1da177e4	223	}
45cfbe35	224	unlock_super(sb);
3d23985d	225	return d_splice_alias(inode, dentry);
1da177e4 LT	226	}
	227
	228	/***** Creates a directory entry (name is already formatted). */
	229	static int msdos_add_entry(struct inode dir, const unsigned char name,
	230	int is_dir, int is_hid, int cluster,
	231	struct timespec ts, struct fat_slot_info sinfo)
	232	{
b271e067	233	struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
1da177e4 LT	234	struct msdos_dir_entry de;
	235	__le16 time, date;
	236	int err;
	237
	238	memcpy(de.name, name, MSDOS_NAME);
	239	de.attr = is_dir ? ATTR_DIR : ATTR_ARCH;
	240	if (is_hid)
	241	de.attr \|= ATTR_HIDDEN;
	242	de.lcase = 0;
7decd1cb	243	fat_time_unix2fat(sbi, ts, &time, &date, NULL);
1da177e4 LT	244	de.cdate = de.adate = 0;
	245	de.ctime = 0;
	246	de.ctime_cs = 0;
	247	de.time = time;
	248	de.date = date;
a943ed71	249	fat_set_start(&de, cluster);
1da177e4 LT	250	de.size = 0;
	251
	252	err = fat_add_entries(dir, &de, 1, sinfo);
	253	if (err)
	254	return err;
	255
	256	dir->i_ctime = dir->i_mtime = *ts;
	257	if (IS_DIRSYNC(dir))
	258	(void)fat_sync_inode(dir);
	259	else
	260	mark_inode_dirty(dir);
	261
	262	return 0;
	263	}
	264
	265	/***** Create a file */
4acdaf27	266	static int msdos_create(struct inode dir, struct dentry dentry, umode_t mode,
ebfc3b49	267	bool excl)
1da177e4 LT	268	{
1da177e4 LT	269	struct super_block *sb = dir->i_sb;
ae78bf9c	270	struct inode *inode = NULL;
1da177e4 LT	271	struct fat_slot_info sinfo;
	272	struct timespec ts;
	273	unsigned char msdos_name[MSDOS_NAME];
	274	int err, is_hid;
	275
8f593427	276	lock_super(sb);
1da177e4 LT	277
	278	err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
	279	msdos_name, &MSDOS_SB(sb)->options);
	280	if (err)
	281	goto out;
	282	is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
	283	/* Have to do it due to foo vs. .foo conflicts */
	284	if (!fat_scan(dir, msdos_name, &sinfo)) {
	285	brelse(sinfo.bh);
	286	err = -EINVAL;
	287	goto out;
	288	}
	289
	290	ts = CURRENT_TIME_SEC;
	291	err = msdos_add_entry(dir, msdos_name, 0, is_hid, 0, &ts, &sinfo);
	292	if (err)
	293	goto out;
	294	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
	295	brelse(sinfo.bh);
	296	if (IS_ERR(inode)) {
	297	err = PTR_ERR(inode);
	298	goto out;
	299	}
	300	inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
	301	/* timestamp is already written, so mark_inode_dirty() is unneeded. */
	302
	303	d_instantiate(dentry, inode);
	304	out:
8f593427	305	unlock_super(sb);
ae78bf9c CM	306	if (!err)
ae78bf9c CM	307	err = fat_flush_inodes(sb, dir, inode);
1da177e4 LT	308	return err;
	309	}
	310
	311	/***** Remove a directory */
	312	static int msdos_rmdir(struct inode dir, struct dentry dentry)
	313	{
8f593427	314	struct super_block *sb = dir->i_sb;
1da177e4 LT	315	struct inode *inode = dentry->d_inode;
	316	struct fat_slot_info sinfo;
	317	int err;
	318
8f593427	319	lock_super(sb);
1da177e4 LT	320	/*
	321	* Check whether the directory is not in use, then check
	322	* whether it is empty.
	323	*/
	324	err = fat_dir_empty(inode);
	325	if (err)
	326	goto out;
	327	err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
	328	if (err)
	329	goto out;
	330
	331	err = fat_remove_entries(dir, &sinfo); /* and releases bh */
	332	if (err)
	333	goto out;
9a53c3a7	334	drop_nlink(dir);
1da177e4	335
ce71ec36	336	clear_nlink(inode);
1da177e4 LT	337	inode->i_ctime = CURRENT_TIME_SEC;
	338	fat_detach(inode);
	339	out:
8f593427	340	unlock_super(sb);
ae78bf9c	341	if (!err)
8f593427	342	err = fat_flush_inodes(sb, dir, inode);
1da177e4 LT	343
	344	return err;
	345	}
	346
	347	/***** Make a directory */
18bb1db3	348	static int msdos_mkdir(struct inode dir, struct dentry dentry, umode_t mode)
1da177e4 LT	349	{
	350	struct super_block *sb = dir->i_sb;
	351	struct fat_slot_info sinfo;
	352	struct inode *inode;
	353	unsigned char msdos_name[MSDOS_NAME];
	354	struct timespec ts;
	355	int err, is_hid, cluster;
	356
8f593427	357	lock_super(sb);
1da177e4 LT	358
	359	err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
	360	msdos_name, &MSDOS_SB(sb)->options);
	361	if (err)
	362	goto out;
	363	is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
	364	/* foo vs .foo situation */
	365	if (!fat_scan(dir, msdos_name, &sinfo)) {
	366	brelse(sinfo.bh);
	367	err = -EINVAL;
	368	goto out;
	369	}
	370
	371	ts = CURRENT_TIME_SEC;
	372	cluster = fat_alloc_new_dir(dir, &ts);
	373	if (cluster < 0) {
	374	err = cluster;
	375	goto out;
	376	}
	377	err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
	378	if (err)
	379	goto out_free;
d8c76e6f	380	inc_nlink(dir);
1da177e4 LT	381
	382	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
	383	brelse(sinfo.bh);
	384	if (IS_ERR(inode)) {
	385	err = PTR_ERR(inode);
	386	/* the directory was completed, just return a error */
	387	goto out;
	388	}
bfe86848	389	set_nlink(inode, 2);
1da177e4 LT	390	inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
	391	/* timestamp is already written, so mark_inode_dirty() is unneeded. */
	392
	393	d_instantiate(dentry, inode);
	394
8f593427	395	unlock_super(sb);
ae78bf9c	396	fat_flush_inodes(sb, dir, inode);
1da177e4 LT	397	return 0;
	398
	399	out_free:
	400	fat_free_clusters(dir, cluster);
	401	out:
8f593427	402	unlock_super(sb);
1da177e4 LT	403	return err;
	404	}
	405
	406	/***** Unlink a file */
	407	static int msdos_unlink(struct inode dir, struct dentry dentry)
	408	{
	409	struct inode *inode = dentry->d_inode;
85cb9bf5	410	struct super_block *sb = inode->i_sb;
1da177e4 LT	411	struct fat_slot_info sinfo;
	412	int err;
	413
8f593427	414	lock_super(sb);
1da177e4 LT	415	err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
	416	if (err)
	417	goto out;
	418
	419	err = fat_remove_entries(dir, &sinfo); /* and releases bh */
	420	if (err)
	421	goto out;
ce71ec36	422	clear_nlink(inode);
1da177e4 LT	423	inode->i_ctime = CURRENT_TIME_SEC;
	424	fat_detach(inode);
	425	out:
8f593427	426	unlock_super(sb);
ae78bf9c	427	if (!err)
8f593427	428	err = fat_flush_inodes(sb, dir, inode);
1da177e4 LT	429
	430	return err;
	431	}
	432
	433	static int do_msdos_rename(struct inode old_dir, unsigned char old_name,
	434	struct dentry *old_dentry,
	435	struct inode new_dir, unsigned char new_name,
	436	struct dentry *new_dentry, int is_hid)
	437	{
	438	struct buffer_head *dotdot_bh;
	439	struct msdos_dir_entry *dotdot_de;
1da177e4 LT	440	struct inode old_inode, new_inode;
	441	struct fat_slot_info old_sinfo, sinfo;
	442	struct timespec ts;
7669e8fb	443	loff_t new_i_pos;
1da177e4 LT	444	int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
	445
	446	old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
	447	old_inode = old_dentry->d_inode;
	448	new_inode = new_dentry->d_inode;
	449
	450	err = fat_scan(old_dir, old_name, &old_sinfo);
	451	if (err) {
	452	err = -EIO;
	453	goto out;
	454	}
	455
	456	is_dir = S_ISDIR(old_inode->i_mode);
	457	update_dotdot = (is_dir && old_dir != new_dir);
	458	if (update_dotdot) {
7669e8fb	459	if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de)) {
1da177e4 LT	460	err = -EIO;
	461	goto out;
	462	}
	463	}
	464
	465	old_attrs = MSDOS_I(old_inode)->i_attrs;
	466	err = fat_scan(new_dir, new_name, &sinfo);
	467	if (!err) {
	468	if (!new_inode) {
	469	/* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
	470	if (sinfo.de != old_sinfo.de) {
	471	err = -EINVAL;
	472	goto out;
	473	}
	474	if (is_hid)
	475	MSDOS_I(old_inode)->i_attrs \|= ATTR_HIDDEN;
	476	else
	477	MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
	478	if (IS_DIRSYNC(old_dir)) {
	479	err = fat_sync_inode(old_inode);
	480	if (err) {
	481	MSDOS_I(old_inode)->i_attrs = old_attrs;
	482	goto out;
	483	}
	484	} else
	485	mark_inode_dirty(old_inode);
	486
	487	old_dir->i_version++;
	488	old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
	489	if (IS_DIRSYNC(old_dir))
	490	(void)fat_sync_inode(old_dir);
	491	else
	492	mark_inode_dirty(old_dir);
	493	goto out;
	494	}
	495	}
	496
	497	ts = CURRENT_TIME_SEC;
	498	if (new_inode) {
	499	if (err)
	500	goto out;
1da177e4 LT	501	if (is_dir) {
	502	err = fat_dir_empty(new_inode);
	503	if (err)
	504	goto out;
	505	}
9131dd42	506	new_i_pos = MSDOS_I(new_inode)->i_pos;
1da177e4 LT	507	fat_detach(new_inode);
	508	} else {
	509	err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
	510	&ts, &sinfo);
	511	if (err)
	512	goto out;
9131dd42	513	new_i_pos = sinfo.i_pos;
1da177e4 LT	514	}
	515	new_dir->i_version++;
	516
	517	fat_detach(old_inode);
9131dd42	518	fat_attach(old_inode, new_i_pos);
1da177e4 LT	519	if (is_hid)
	520	MSDOS_I(old_inode)->i_attrs \|= ATTR_HIDDEN;
	521	else
	522	MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
	523	if (IS_DIRSYNC(new_dir)) {
	524	err = fat_sync_inode(old_inode);
	525	if (err)
	526	goto error_inode;
	527	} else
	528	mark_inode_dirty(old_inode);
	529
	530	if (update_dotdot) {
a943ed71	531	fat_set_start(dotdot_de, MSDOS_I(new_dir)->i_logstart);
b522412a	532	mark_buffer_dirty_inode(dotdot_bh, old_inode);
1da177e4 LT	533	if (IS_DIRSYNC(new_dir)) {
	534	err = sync_dirty_buffer(dotdot_bh);
	535	if (err)
	536	goto error_dotdot;
	537	}
9a53c3a7	538	drop_nlink(old_dir);
1da177e4	539	if (!new_inode)
d8c76e6f	540	inc_nlink(new_dir);
1da177e4 LT	541	}
	542
	543	err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */
	544	old_sinfo.bh = NULL;
	545	if (err)
	546	goto error_dotdot;
	547	old_dir->i_version++;
	548	old_dir->i_ctime = old_dir->i_mtime = ts;
	549	if (IS_DIRSYNC(old_dir))
	550	(void)fat_sync_inode(old_dir);
	551	else
	552	mark_inode_dirty(old_dir);
	553
	554	if (new_inode) {
9a53c3a7	555	drop_nlink(new_inode);
1da177e4	556	if (is_dir)
9a53c3a7	557	drop_nlink(new_inode);
1da177e4 LT	558	new_inode->i_ctime = ts;
	559	}
	560	out:
	561	brelse(sinfo.bh);
	562	brelse(dotdot_bh);
	563	brelse(old_sinfo.bh);
	564	return err;
	565
	566	error_dotdot:
	567	/* data cluster is shared, serious corruption */
	568	corrupt = 1;
	569
	570	if (update_dotdot) {
a943ed71	571	fat_set_start(dotdot_de, MSDOS_I(old_dir)->i_logstart);
b522412a	572	mark_buffer_dirty_inode(dotdot_bh, old_inode);
1da177e4 LT	573	corrupt \|= sync_dirty_buffer(dotdot_bh);
	574	}
	575	error_inode:
	576	fat_detach(old_inode);
	577	fat_attach(old_inode, old_sinfo.i_pos);
	578	MSDOS_I(old_inode)->i_attrs = old_attrs;
	579	if (new_inode) {
9131dd42	580	fat_attach(new_inode, new_i_pos);
1da177e4 LT	581	if (corrupt)
	582	corrupt \|= fat_sync_inode(new_inode);
	583	} else {
	584	/*
	585	* If new entry was not sharing the data cluster, it
	586	* shouldn't be serious corruption.
	587	*/
	588	int err2 = fat_remove_entries(new_dir, &sinfo);
	589	if (corrupt)
	590	corrupt \|= err2;
	591	sinfo.bh = NULL;
	592	}
	593	if (corrupt < 0) {
85c78591	594	fat_fs_error(new_dir->i_sb,
1da177e4	595	"%s: Filesystem corrupted (i_pos %lld)",
8e24eea7	596	__func__, sinfo.i_pos);
1da177e4 LT	597	}
	598	goto out;
	599	}
	600
	601	/***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
	602	static int msdos_rename(struct inode old_dir, struct dentry old_dentry,
	603	struct inode new_dir, struct dentry new_dentry)
	604	{
8f593427	605	struct super_block *sb = old_dir->i_sb;
1da177e4 LT	606	unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
	607	int err, is_hid;
	608
8f593427	609	lock_super(sb);
1da177e4 LT	610
	611	err = msdos_format_name(old_dentry->d_name.name,
	612	old_dentry->d_name.len, old_msdos_name,
	613	&MSDOS_SB(old_dir->i_sb)->options);
	614	if (err)
	615	goto out;
	616	err = msdos_format_name(new_dentry->d_name.name,
	617	new_dentry->d_name.len, new_msdos_name,
	618	&MSDOS_SB(new_dir->i_sb)->options);
	619	if (err)
	620	goto out;
	621
	622	is_hid =
	623	(new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');
	624
	625	err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
	626	new_dir, new_msdos_name, new_dentry, is_hid);
	627	out:
8f593427	628	unlock_super(sb);
ae78bf9c	629	if (!err)
8f593427	630	err = fat_flush_inodes(sb, old_dir, new_dir);
1da177e4 LT	631	return err;
	632	}
	633
92e1d5be	634	static const struct inode_operations msdos_dir_inode_operations = {
1da177e4 LT	635	.create = msdos_create,
	636	.lookup = msdos_lookup,
	637	.unlink = msdos_unlink,
	638	.mkdir = msdos_mkdir,
	639	.rmdir = msdos_rmdir,
	640	.rename = msdos_rename,
1278fdd3	641	.setattr = fat_setattr,
da63fc7c	642	.getattr = fat_getattr,
1da177e4 LT	643	};
1da177e4 LT	644
3d23985d	645	static void setup(struct super_block *sb)
1da177e4	646	{
384f5c96	647	MSDOS_SB(sb)->dir_ops = &msdos_dir_inode_operations;
3d23985d	648	sb->s_d_op = &msdos_dentry_operations;
1da177e4	649	sb->s_flags \|= MS_NOATIME;
3d23985d AV	650	}
	651
	652	static int msdos_fill_super(struct super_block sb, void data, int silent)
	653	{
384f5c96	654	return fat_fill_super(sb, data, silent, 0, setup);
1da177e4 LT	655	}
1da177e4 LT	656
152a0836	657	static struct dentry msdos_mount(struct file_system_type fs_type,
454e2398	658	int flags, const char *dev_name,
152a0836	659	void *data)
1da177e4	660	{
152a0836	661	return mount_bdev(fs_type, flags, dev_name, data, msdos_fill_super);
1da177e4 LT	662	}
	663
	664	static struct file_system_type msdos_fs_type = {
	665	.owner = THIS_MODULE,
	666	.name = "msdos",
152a0836	667	.mount = msdos_mount,
1da177e4 LT	668	.kill_sb = kill_block_super,
	669	.fs_flags = FS_REQUIRES_DEV,
	670	};
	671
	672	static int __init init_msdos_fs(void)
	673	{
	674	return register_filesystem(&msdos_fs_type);
	675	}
	676
	677	static void __exit exit_msdos_fs(void)
	678	{
	679	unregister_filesystem(&msdos_fs_type);
	680	}
	681
	682	MODULE_LICENSE("GPL");
	683	MODULE_AUTHOR("Werner Almesberger");
	684	MODULE_DESCRIPTION("MS-DOS filesystem support");
	685
	686	module_init(init_msdos_fs)
	687	module_exit(exit_msdos_fs)