How to restore btrfs snapshot with out reboot?

Question

If I make a btrfs snapshot of my / folder as described here, I can't roll back until I restart the PC, because I can't delete the old btrfs subvolume with btrfs subvolume delete @_baroot. It will simply tell me it's still in use.

Answer 1

I doubt that this is possible or even should be possible without a reboot. The root directory holds some pretty important system parts that shouldn't be changed at runtime. You can either

• copy the files or directories you want to roll back with cp --reflink,

• boot a live system and move the snapshot folder around, or

• change the default subvolume (source)

  # btrfs subvolume list /
  ID 258 gen 9512 top level 5 path root_subvolume
  ID 259 gen 9512 top level 258 path home
  ID 260 gen 9512 top level 258 path var
  ID 261 gen 9512 top level 258 path usr
  # btrfs subvolume set-default 258 /
  

  and reboot.