silent-filesystem-corruption.sh

cleanup() {
  sudo umount a
  rm a.img
  sudo losetup -d /dev/loop0
}

set -eu
mkdir -p a
truncate -s 128k a.img
mkfs.ext4 a.img >/dev/null 2>&1
sudo losetup -P -f a.img
sudo mount /dev/loop0 a
seq 5000 | sudo tee a/b >/dev/null
sudo umount a
dd if=<(echo FAILED) of=a.img bs=100 count=1 conv=notrunc seek=500 >/dev/null 2>&1
sudo mount /dev/loop0 a
fgrep -2 FAIL a/b