An integrity verifier and
validator is provided in which an initial anti-
virus scan is performed against an entire
file system to verify the integrity of the
file system and create a corresponding
file system level integrity
verification database of known scanned regions of the file
system. The
database contains a copy of the file
system's partition table referencing the range of occupied inodes and
directory blocks. When new or updated content is written to the file
system the integrity of the corresponding occupied inodes and
directory blocks is no longer assured, and the integrity verifier flags them on the
database for rescanning. Subsequent attempts to rescan any portion of the file system triggers the integrity
validator to scan the database to validate whether that portion of the file system falls within any of the occupied inodes or
directory blocks that have been flagged for rescanning. If they are not flagged, then rescanning of that portion of the file system is unnecessary as the integrity of at least that portion is assured. However, if they are flagged, then the anti-
virus software rescans that portion of the file system for the presence of viruses.