#!/usr/bin/env bash

# reference:
# https://www.kernel.org/doc/Documentation/filesystems/ext4.txt
# https://wiki.archlinux.org/title/ext4
#
# -m reserved-blocks-percentage
# -F Force mke2fs to create a filesystem, even if the specified device is not a partition on a block special device
#
# -O feature
# from  /etc/mke2fs.conf
# defaults: has_journal,extent,huge_file,flex_bg,metadata_csum,64bit,dir_nlink,extra_isize
# disabling journalling, since it's a read-only fs, as well as other unused features
# extent is actually needed for tail packing small files
#
# -E extended-options
# lazy_itable_init - inode table is fully initialized at the time of file system creation
# nodiscard - Do not attempt to discard blocks at mkfs time.
#
# inode_size = 128 (minimum)
# inode_ratio = 16384 (default but experimenting)


sudo umount mnt || true
rm -rf mnt
rm -f image.ext4


# make a sparse file
# make sure it's bigger then the current OSM output
fallocate -l 200G image.ext4


mke2fs -t ext4 -v \
  -m 0 \
  -F \
  -O ^has_journal,^huge_file,^metadata_csum,^64bit,^extra_isize \
  -E lazy_itable_init=0,nodiscard \
  -I 128 \
  -i 16384 \
  image.ext4

mkdir mnt
sudo mount -v \
  -t ext4 \
  -o nobarrier,noatime \
  image.ext4 mnt

sudo chown ofm:ofm -R mnt

/data/ofm/venv/bin/python ../../tile_gen/extract.py output.mbtiles mnt/extract \
  > "extract_out.log" 2> "extract_err.log"

sudo umount mnt

e2fsck -vf image.ext4 && \
  resize2fs -M image.ext4 && \
  e2fsck -vf image.ext4

# default to read-only mode
tune2fs -E mount_opts=ro image.ext4