Study case:
An automatic backup system from all family members via OpenVPN.
A lot of files (especially photos) are common between family members.
So, with a script I replace identical files with hard links.
Then a problem arise: If a user change its file, file changes for all of users. Deletion of file is not a problem, nor rename. Only change of file contents.
So I want when a user changes its file which is a hard link, then hard link eliminated and a copy of original file created with applied changes.
Is this possible with any filesystem or any hack or feature?
