recursive btrfs snapshots

SnapName=backup.`date +%Y%m%d--%H%M%S`
btrfs fi show 2>/dev/null | awk '/ path / {print $NF}' | while read path; do
  SafePath=`echo "$path" | tr / .`
  TmpMountDir=`mktemp -d /tmp/.btrfs.mount.$SafePath.XXXXXX`
  mount -t btrfs $path $TmpMountDir
  (btrfs subv list -ar $TmpMountDir; btrfs subv list -a $TmpMountDir) | sort | uniq -u | while read _id Id _gen Gen _top _level Toplevel _path Path; do
    btrfs subv snaps -r "$TmpMountDir/$Path" "$TmpMountDir/$Path.$SnapName"
  done
  umount $TmpMountDir
  rmdir $TmpMountDir
done