Resizing lvm2 logical volume and file system: Exact sizes?
Solution 1:
In my experience, LVM and resize2fs have the same ideas about what "97G" means, so specifying the same size in both places should be fine. However, I'm paranoid, and wherever possible always use the strategy suggested by larsks in the question comments and resized to be one GB smaller than I wanted, done the lvresize to the size I wanted, and then re-run resize2fs (without a size) to let it expand back out to fill the whole LV.
Solution 2:
I think this is best done using the --resizefs option to lvreduce/lvresize:
-r, --resizefs
Resize underlying filesystem together with the logical volume using fsadm(8).
Admittedly, that doesn't help you now, but it may in the future.