#!/bin/bash

BLOCKSIZE=4096
CHUNKSIZE_MD0=4096
#CHUNKSIZE_MD0=131072
CHUNKSIZE_MD1=131072
MEMBERS_MD0=23
MEMBERS_MD1=6
BCACHE_META_SIZE=8192

EXT4_STRIDE=$((CHUNKSIZE_MD1/BLOCKSIZE))
EXT4_STRIPE_WIDTH=$(())
EXT4_INODE_RATIO=33554432
EXT4_INODE_SIZE=256
STRIPE_WIDTH_MD0=$((CHUNKSIZE_MD0*MEMBERS_MD0))
STRIPE_WIDTH_MD1=$((CHUNKSIZE_MD1*MEMBERS_MD1))
BCACHE_OFFSET_MD0=$((STRIPE_WIDTH_MD0/512))
BCACHE_OFFSET_MD1=$((STRIPE_WIDTH_MD1/512))
BCACHE_BUCKET_SIZE=16777216


n=2
A[0]=${STRIPE_WIDTH_MD0}
A[1]=${STRIPE_WIDTH_MD1}

prev=${A[0]}
next=${A[1]}

for ((i=1;i<=n;i++));do
  temp1=$prev
  temp2=$next
  #find the GCD
  while [ $prev -ne $next ];do
    if [ $prev -gt $next ];then
      prev=`expr $prev - $next`
    else
      next=`expr $next - $prev`
    fi
  done
  gcd=$prev
  # now get the LCM
  buff=`expr $temp1 \* $temp2`
  lcm=`expr $buff / $gcd`
  next=${A[$i]}
  prev=$lcm
done

EXT4_STRIPE_WIDTH=$((lcm/BLOCKSIZE))

echo "CHUNKSIZE_MD0 $CHUNKSIZE_MD0"
echo "CHUNKSIZE_MD1 $CHUNKSIZE_MD1"
echo "EXT4_STRIPE_WIDTH $EXT4_STRIPE_WIDTH"
echo "EXT4_STRIDE $EXT4_STRIDE"
echo "BCACHE_OFFSET_MD0 $BCACHE_OFFSET_MD0"
echo "BCACHE_OFFSET_MD1 $BCACHE_OFFSET_MD1"

#exit

#FS_UUID=$(blkid -o value -s UUID /dev/md1)

if [ "$WIPE_RAID" = "yes" ]; then
  #UUID_CACHE_OLD=$(lsblk -ndo UUID /dev/md0)
  UUID_CACHE_OLD=$(bcache-super-show -f /dev/md0 | tail -1 | awk '{ print $2 }')

  ###unmount###
  umount /mnt/bcache0
  ###wipe bcache###
  echo 1 > /sys/fs/bcache/${UUID_CACHE_OLD}/unregister
  echo 1 > /sys/block/bcache0/bcache/stop
  wipefs -a /dev/md0
  wipefs -a /dev/md1

#mdadm /dev/md127 --fail detached --remove detached
  ###wipe md raid###
  mdadm --stop /dev/md0
  mdadm --stop /dev/md1
  #  mdadm -v --zero-superblock /dev/sdh2 /dev/sdi2 /dev/sdd3 /dev/sdc3 /dev/sdg2 /dev/sdb3 /dev/sdf1 /dev/sda4 /dev/nvme0n1p3 /dev/nvme0n1p4 /dev/sda3 /dev/sde1 /dev/nvme0n1p2 /dev/nvme0n1p1
  mdadm -v --zero-superblock /dev/sdf1 /dev/nvme0n1p1 /dev/nvme0n1p2 /dev/sde1 /dev/nvme0n1p3 /dev/nvme0n1p4 \
    /dev/sda3 /dev/nvme0n1p5 /dev/nvme0n1p6 /dev/sde2 /dev/nvme0n1p7 /dev/nvme0n1p8 /dev/sda4 /dev/nvme0n1p9 /dev/nvme0n1p10 /dev/sdf2 /dev/nvme0n1p11 /dev/nvme0n1p12 /dev/sda5 \
    /dev/nvme0n1p13 /dev/nvme0n1p14 /dev/nvme0n1p15 /dev/nvme0n1p16
  mdadm -v --zero-superblock /dev/sdb3 /dev/sdc3 /dev/sdd3 /dev/sdg2 /dev/sdh1 /dev/sdi1
fi

###need sanity checks here/everywhere###

if [ "$CREATE_RAID" = "yes" ]; then

  ###create new md raids###
  mdadm --create --verbose --assume-clean -f /dev/md0 --level=stripe --raid-devices=${MEMBERS_MD0} --chunk=${CHUNKSIZE_MD0} /dev/sdf1 /dev/nvme0n1p1 /dev/nvme0n1p2 /dev/sde1 /dev/nvme0n1p3 /dev/nvme0n1p4 \
    /dev/sda3 /dev/nvme0n1p5 /dev/nvme0n1p6 /dev/sde2 /dev/nvme0n1p7 /dev/nvme0n1p8 /dev/sda4 /dev/nvme0n1p9 /dev/nvme0n1p10 /dev/sdf2 /dev/nvme0n1p11 /dev/nvme0n1p12 /dev/sda5 \
    /dev/nvme0n1p13 /dev/nvme0n1p14 /dev/nvme0n1p15 /dev/nvme0n1p16
  #mdadm --create --verbose --assume-clean -f /dev/md0 --level=stripe --raid-devices=12 --chunk=128K /dev/nvme0n1p1 /dev/nvme0n1p2 /dev/sda3 /dev/nvme0n1p3 /dev/sde1 /dev/nvme0n1p4 /dev/nvme0n1p5 /dev/sdf1 /dev/nvme0n1p6 /dev/sda4 /dev/nvme0n1p7 /dev/nvme0n1p8
  mdadm --create --verbose --assume-clean -f /dev/md1 --level=stripe --raid-devices=${MEMBERS_MD1} --chunk=${CHUNKSIZE_MD1} /dev/sdb3 /dev/sdc3 /dev/sdd3 /dev/sdg2 /dev/sdh1 /dev/sdi1
  ###create new bcache devices###
  bcache make --force -B -b ${BCACHE_BUCKET_SIZE} -w ${BLOCKSIZE} -o ${BCACHE_OFFSET_MD1} /dev/md1
  bcache make --force -C -b ${BCACHE_BUCKET_SIZE} -w ${BLOCKSIZE} -o ${BCACHE_OFFSET_MD0} /dev/md0

  #UUID_CACHE_NEW=$(lsblk -ndo UUID /dev/md0)
  UUID_CACHE_NEW=$(bcache-super-show -f /dev/md0 | tail -1 | awk '{ print $2 }')

  ###setup bcache backing device settings###
  echo writeback > /sys/block/bcache0/bcache/cache_mode
  echo 0 > /sys/block/bcache0/bcache/sequential_cutoff
  echo 40 > /sys/block/bcache0/bcache/writeback_percent
  echo 3600 > /sys/block/bcache0/bcache/writeback_delay
  echo 0 > /sys/block/bcache0/bcache/writeback_rate
  ###attach bcache cache set to backing device###
  echo ${UUID_CACHE_NEW} > /sys/block/bcache0/bcache/attach

  #EXT4_STRIPE_WIDTH=$((STRIPE_WIDTH_MD1/BLOCKSIZE))

  ###partition and mount bcache device###
  mke2fs -t ext4 -v -i ${EXT4_INODE_RATIO} -I ${EXT4_INODE_SIZE} -b ${BLOCKSIZE} -m .1 -O ^has_journal -E stride=${EXT4_STRIDE},stripe-width=${EXT4_STRIPE_WIDTH} /dev/bcache0
  mkdir /mnt/bcache0
  mount /dev/bcache0 /mnt/bcache0
  chown soul.users /mnt/bcache0
  ###setup bcache cache device settings###
  echo 0 > /sys/fs/bcache/${UUID_CACHE_NEW}/cache0/discard
  echo 0 > /sys/fs/bcache/${UUID_CACHE_NEW}/congested_read_threshold_us
  echo 0 > /sys/fs/bcache/${UUID_CACHE_NEW}/congested_write_threshold_us
  #echo 0 > /sys/block/bcache0/bcache/writeback_running
  echo 50 > /sys/fs/bcache/${UUID_CACHE_NEW}/journal_delay_ms
  #echo 0 > /sys/block/bcache0/bcache/writeback_running
  #echo 0 > /sys/fs/bcache/${UUID_CACHE_NEW}/synchronous
fi