1. A method of ascending a file system capable of distinguishing, based on relative depth, between multiple unique paths to the same directory, the method comprising: receiving, by a computer processor, a request to ascend from a child directory to an expected parent directory of a file system organized in a hierarchy, the expected parent directory being one of multiple possible parent directories; determining, by a computer processor, the expected parent directory by evaluating, in part, a relative depth value of the child directory, wherein the relative depth value indicates how far the child directory is from a portal, wherein the portal is an entry point in the file system that is at the same level or a higher level than the expected parent directory in the hierarchy, the determining performed without the need to identify the path or the entry point; and ascending, by a computer processor, to the expected parent directory, wherein the file system is a multiple-version file system comprising current versions of data, snapshot versions of data, and portals to snapshots of data, and wherein the child directory is a snapshot version of data and wherein the relative depth value indicates how far the child directory is from its snapshot portal.