Metadata about an original file system is saved at the time of creation of
a clone file system of the original file system. The metadata is used at
a later time to detect changes to the original file system. These changes
are then applied to the clone file system which has its own changes
different from the changes of the original file system. Changes made to
the clone file system are merged into the original file system after at
least one boot of a computer system from the clone file system.