fallible_read_node
err = fallible_read_node(c, key, &zbr, node);
static int fallible_read_node(struct ubifs_info *c, const union ubifs_key *key,
err = fallible_read_node(c, &zbr->key, zbr, node);
err = fallible_read_node(c, &zbr->key, zbr, dent);