A system and method for updating a replicated destination file system
snapshot with changes in a source file system snapshot, facilitates
construction of a new directory tree on the destination from source
update information using a temporary or "purgatory" directory that allows
any modified and deleted files on the destination active file system to
be associated with (e.g. moved to) the purgatory directory if and until
they are reused. In addition, an inode map is established on the
destination that maps source inode numbers to destination inode numbers
so as to facilitate building of the destination tree using
inode/generation number tuples. The inode map allows resynchronization of
the source file system to the destination. The inode map also allows
association of two or more destination snapshots to each other based upon
their respective maps with the source.