Mount bcache for pbuilder/build

pbuilder-bcache.sh

#!/bin/bash
set -e

function wait_for_file() {
  for i in $(seq 1 15)
  do
    test -e "$1" && break
    sleep 1
  done
  test -e "$1"
  return $?
}

wait_for_file /var/cache/pbuilder/build-loop.img
wipefs -a /var/cache/pbuilder/build-loop.img
losetup /dev/loop0 /var/cache/pbuilder/build-loop.img
modprobe brd rd_nr=1 rd_size=524288
wait_for_file /dev/ram0
make-bcache -B /dev/loop0 -C /dev/ram0
wait_for_file /sys/fs/bcache/register
echo /dev/ram0 > /sys/fs/bcache/register
wait_for_file /sys/block/bcache0/bcache/cache_mode
echo writeback > /sys/block/bcache0/bcache/cache_mode
wait_for_file /dev/bcache0
wipefs -a /dev/bcache0
mkfs -t ext2 /dev/bcache0
mount -t ext2 /dev/bcache0 /var/cache/pbuilder/build -o noatime
echo DONE