Changing permissions on existing backup source

[Charles Marcus]

Hello,

I have a system that currently uses rsync (via rsnapshot) with 
--link-dest enabled to backup our mail store...

If I change the permissions on the source maildirs, will this cause 
everything to be transferred again? Meaning, will rsync see everything 
as 'modified', thus creating a new copy of the entire mail store on the 
backup target?

Or will the newest backup directory just reflect the new permissions for 
the hardlinked files, without making new copies of everything?