Ditto address indicating true disk address for actual data blocks stored in one of an inode of the file system and subsequent snapshot

摘要

A system, method and computer readable medium for providing a file system snapshot with ditto address feature is disclosed. The method includes generating a file system snapshot wherein the snapshot is substantially empty. When metadata associated with a source file included in the snapshot is modified, the inode corresponding to the source file is copied to a shadow inode in the snapshot. When information is appended to a data block associated with a source file included in the snapshot, the inode corresponding to the source file is also copied to a shadow inode in the snapshot. When information in a data block associated with a source file included in the snapshot is overwritten or deleted, the inode corresponding to the source file is copied to a shadow inode in the snapshot and the original data block corresponding to the source file is copied to the snapshot.