xfs: sanitize remount options

 *

 * Note that this function leaks the various device name allocations on

 * failure.  The caller takes care of them.

 *

 * *sb is const because this is also used to test options on the remount

 * path, and we don't want this to have any side effects at remount time.

 * Today this function does not change *sb, but just to future-proof...

 */

STATIC int

xfs_parseargs(

	struct xfs_mount	*mp,

	char			*options)

{

	struct super_block	*sb = mp->m_super;

	const struct super_block *sb = mp->m_super;

	char			*p;

	substring_t		args[MAX_OPT_ARGS];

	int			dsunit = 0;

	xfs_log_quiesce(mp);

}

STATIC int

xfs_test_remount_options(

	struct super_block	*sb,

	struct xfs_mount	*mp,

	char			*options)

{

	int			error = 0;

	struct xfs_mount	*tmp_mp;

	tmp_mp = kmem_zalloc(sizeof(*tmp_mp), KM_MAYFAIL);

	if (!tmp_mp)

		return -ENOMEM;

	tmp_mp->m_super = sb;

	error = xfs_parseargs(tmp_mp, options);

	xfs_free_fsname(tmp_mp);

	kfree(tmp_mp);

	return error;

}

STATIC int

xfs_fs_remount(

	struct super_block	*sb,

	char			*p;

	int			error;

	/* First, check for complete junk; i.e. invalid options */

	error = xfs_test_remount_options(sb, mp, options);

	if (error)

		return error;

	sync_filesystem(sb);

	while ((p = strsep(&options, ",")) != NULL) {

		int token;