#!/usr/bin/bash
# Usage: borg_partclone_backup.sh VGNAME LVNAME SNP_SZ PART_NO SRV_HOST SRV_BORG_REPO
VGNAME=$1
LVNAME=$2
DATE=`date +%Y%m%dT%H%M%S`
SNP_NM=$LVNAME-$DATE
SNP_SZ=$3
PART_NO=$4
SRV_HOST=$5
SRV_BORG_REPO=$6
SRV_BORG_BACKUP_NAME=$LVNAME-$7-$DATE

exitmsg () {
  echo $1
  exit 1;
}

rmsnap () {
	# Remove the snapshot
	lvremove -y $VGNAME/$SNP_NM >/dev/null
}

rmloop () {
	# Free the loop device
	losetup -D /dev/loop0 >/dev/null

}

exitmsg_rm () {
	rmsnap
  exitmsg $1
}

exitmsg_rm_loop () {
	rmloop
  exitmsg_rm $1
}

exit_ok () {
	rmloop
	rmsnap
	echo "Successful backup for $VGNAME/$LVNAME part. $PART_NO"
}


echo "Starting backup for $VGNAME/$LVNAME part. $PART_NO"

# Be root
test `id -u` == "0" || exitmsg "Run this script as root"

# Create the snapshot
lvcreate -y -n $SNP_NM -s -L $SNP_SZ $VGNAME/$LVNAME >/dev/null || exitmsg "Cannot create snapshot"

# Setup loopback device
losetup -P /dev/loop0 /dev/$VGNAME/$SNP_NM || exitmsg_rm "/dev/loop0 already used"

# Check filesystem
fsck -y /dev/loop0p$PART_NO || exitmsg_rm_loop "Failed to check filesystem /dev/loop0p$PART_NO"

# Clone
partclone.ext4 -s /dev/loop0p$PART_NO -c -q 2>&1 | \
    BORG_UNKNOWN_UNENCRYPTED_REPO_ACCESS_IS_OK=yes \
    borg2 -r ssh://$SRV_HOST$SRV_BORG_REPO create --stdin-name image.pcl $SRV_BORG_BACKUP_NAME - || exitmsg_rm_loop "Backup failed for $VGNAME/$SNP_NM part. $PART_NO"

exit_ok