A method of maintaining and providing information relating to file deduplication. A first portion of a first file and a second portion of a second file that contain a first content are identified. A first header associated with the first portion is created. The first header identifies the first portion and the second portion containing the first content. The first header is appended to a storage location of the first content of the first portion to form a first data structure for the first file. The first data structure is stored. The first data structure is provided to an application requesting the first file so that duplicate data processing can be avoided by the application. The first data structure is updated when the first file or the second file are altered. A similar process may occur to generate a data structure for the second file.