1. A method of attaching user storage to a central storage management system, the method comprising: receiving a first request to attach a first cloud-based user storage to the central storage management system; receiving a second request to attach a second cloud-based user storage to the central storage management system; accessing the first and second cloud-based user storages and determining, respectively, first and second sets of objects stored therein; for each object in the first and second sets of objects, storing corresponding metadata in the central storage management system, wherein the metadata indicates the cloud-based user storage at which the corresponding object is stored, and wherein the metadata for each object stores relationship information, the relationship information indicating an immediate parent object corresponding to the object; and updating a file system corresponding to the central storage management system, the file system implementing an object hierarchy based on the relationship information stored in the metadata for each object, wherein the updating of the file system comprises creating, in the file system, a plurality of attributes, each attribute corresponding to an object in the first set of objects.