Patent ID: 9400741
Filing Date: 2016-07-26
CPC Classification: G06F

Claim Text:
1. A method of operating a storage processor to reclaim storage assigned to an upper file system hosting a set of storage objects including primary objects and respective snapshot objects, the storage objects hosted as respective files of the upper file system backed by an underlying file of a lower file system, the underlying file constituted by respective sets of fixed-size blocks of the storage, the method comprising: assigning the storage objects and their respective files to version sets, each primary object and its respective snapshot objects being assigned to a respective distinct version set, the files of each version set selectively sharing blocks, each block having corresponding block-specific block metadata containing a respective version set identifier identifying the version set to which the files constituted by the block are assigned, the blocks of a given file having respective distinct block-specific block metadata, the block metadata forming part of the upper file system; identifying blocks in an extent of the underlying file to be moves, and for each identified block: upon completion of the above for all blocks to be moved, removing the extent from the underlying file.