Patent ID: 8015156

Claim:
A system for preserving access to previous versions of directories and files stored in a processor-accessible storage system, the system comprising: at least one memory; at least one computer processor; a plurality of metadata structures logically arranged in a hierarchical structure and stored on the at least one memory, each metadata structure corresponding to a file or directory of a file system and comprising a governance list configured to store two or more snapshot identifiers, each snapshot identifier identifying a snapshot governing at least the corresponding file or directory, wherein the plurality of metadata structures comprises: a target metadata structure that corresponds to a target file or directory of the file system; and a parent directory metadata structure that corresponds to a parent directory of the file system that is a logical parent of the target file or directory; and at least one executable software module executed by the at least one computer processor and configured to: access a governance list of the parent directory metadata structure, wherein the governance list of the parent directory metadata structure is configured to store two or more snapshot identifiers, and wherein each snapshot identifier identifies a snapshot governing at least the parent directory; identify a snapshot governing the parent directory that also governs the target file or directory and is not reflected in the governance list of the target metadata structure based on the accessed governance list of the parent directory metadata structure; and add a snapshot identifier corresponding to the identified snapshot to a governance list of the target metadata structure.