Why do we need these mount options?

[waxhead <waxhead@dirtcellar.net>]

Howdy,

I was looking through the mount options and being a madman with strong 
opinions I can't help thinking that a lot of them does not really belong 
as mount options at all, but should rather be properties set on the 
subvolume - for example the toplevel subvolume.

And any options set on a child subvolume should override the parrent 
subvolume the way I see it.

By having a quick look - I don't see why these should be mount options 
at all.

autodefrag / noautodefrag
commit
compress / compress-force
datacow / nodatacow
datasum / nodatasum
discard / nodiscard
inode_cache / noinode_cache
space_cache / nospace_cache
sdd / ssd_spread / nossd / no_ssdspread
user_subvol_rm_allowed

Stuff like compress and nodatacow can be set with chattr so there is as 
far as I am aware three methods of setting compression for example.

Either by mount options in fstab, by chattr or by btrfs property set

I think it would be more consistent to have one interface for adjusting 
behavior.

As I asked before, the future plan to have different storage profiles on 
subvolumes seem to have been sneakily(?) removed from the wiki - if that 
is indeed a dropped goal I can see why it makes sense to keep the mount 
options, if not I think the mount options should go in favor of btrfs 
property set.