I created an LVM snapshot, then I modified the original logical volume, and now I see that I probably allocated too much space to hold the snapshot. And I want to reclaim some free space by reducing the space allocated for the snapshot.
How can I check how much the space allocated for a snapshot can be reduced without breaking the snapshot?
In other words: How to find out the space actually needed at the current moment for a snapshot to continue to exist?
(If I know this minimal necessary size, then I probably can simply use
lvreduce to reclaim more free space for the VG from the snapshot.)