Analyzing and correcting corruption which caused filesystem checker failure so that the filesystem checker will run without error

A processor-implemented method for repairing a corrupted filesystem, wherein the corrupted filesystem comprises a plurality of corrupted metadata structures, the method comprising:

• determining, by a processor, a plurality of missing metadata structures associated with the corrupted filesystem, wherein the missing metadata structures have been overwritten by a corruption;
• determining a plurality of current addresses corresponding to a plurality of valid metadata structures in a hierarchical metadata structure of the corrupted filesystem based on the determined plurality of missing metadata structures, wherein at least one metadata structure within the plurality of metadata structures serves as a node pointing to a plurality of other metadata structures;
• locating the plurality of missing metadata structures and a plurality of addresses associated with the missing metadata structures based on the determined plurality of current addresses corresponding to a plurality of valid metadata structures;
• determining whether the located plurality of missing metadata structures can be rebuilt based on locating the plurality of addresses associated with the missing metadata structures, wherein determining whether the located plurality of missing metadata structures can be rebuilt comprises obtaining a plurality of additional data through computation of a plurality of values in the located plurality of addresses;
• rebuilding the plurality of missing metadata structures based on the determining the located plurality of missing metadata structures can be rebuilt, wherein the rebuilding comprises assigning the located plurality of address to the plurality of missing metadata structures and redirecting the plurality of missing metadata structures to point to a correct plurality of other metadata structures;
• in response to determining the located plurality of missing metadata structures cannot be rebuilt, generating an analysis of the corrupted filesystem and an explanation as to why the corrupted filesystem cannot be fixed, wherein generating an analysis includes determining where a plurality of changes have been made, a volume needed to be updated, and a page offset where an update needs to occur;
• and
• displaying the generated analysis and the explanation as to why the corrupted filesystem cannot be fixed along with a plurality of recommended changes to the located plurality of missing metadata structures.