Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

static int ovl_lookup_layer(struct dentry *base, struct ovl_lookup_data *d,

			    struct dentry **ret)

{

	const char *s = d->name.name;

	/* Counting down from the end, since the prefix can change */

	size_t rem = d->name.len - 1;

	struct dentry *dentry = NULL;

	int err;

	if (*s != '/')

	if (d->name.name[0] != '/')

		return ovl_lookup_single(base, d, d->name.name, d->name.len,

					 0, "", ret);

	while (*s++ == '/' && !IS_ERR_OR_NULL(base) && d_can_lookup(base)) {

	while (!IS_ERR_OR_NULL(base) && d_can_lookup(base)) {

		const char *s = d->name.name + d->name.len - rem;

		const char *next = strchrnul(s, '/');

		size_t slen = strlen(s);

		size_t thislen = next - s;

		bool end = !next[0];

		if (WARN_ON(slen > d->name.len) ||

		    WARN_ON(strcmp(d->name.name + d->name.len - slen, s)))

		/* Verify we did not go off the rails */

		if (WARN_ON(s[-1] != '/'))

			return -EIO;

		err = ovl_lookup_single(base, d, s, next - s,

					d->name.len - slen, next, &base);

		err = ovl_lookup_single(base, d, s, thislen,

					d->name.len - rem, next, &base);

		dput(dentry);

		if (err)

			return err;

		dentry = base;

		s = next;

		if (end)

			break;

		rem -= thislen + 1;

		if (WARN_ON(rem >= d->name.len))

			return -EIO;

	}

	*ret = dentry;

	return 0;