US Patent 9916191 Techniques for efficiently performing a filesystem consistency check

A method of efficiently checking a filesystem for errors is provided, the filesystem including a set of data blocks and a set of VBPs, the set of VBPs arranged in a set of VBP blocks, each VBP block storing a plurality of the VBPs. The method includes multiple stages, one stage including iterating through VBP blocks of the filesystem to generate a validity bitmap, and a later stage including traversing a block pointer structure associated with each of a set of files of the filesystem, the traversal making reference to the validity bitmap.