#!/bin/sh
#
# This script is to create lvm snapshot, mount it, umount it and remove in a
# specified number of loops to test whether it will crash the host server.
# All LVM snapshots assumed can be mounted like if you are running a PV domU.
#
# Created by Giam Teck Choon
#

# The LV name and for this case we are using the first in vgdisplay output.
# Change the variable if you want other VG Name
LVGroupName=`vgdisplay | grep 'VG Name' | awk '{print $3}' | tail -n 1`

if [ ! -n "$LVGroupName" ] && [ ! -d "/dev/${LVGroupName}" ] ; then
    echo "Unable to detect VG Name!"
    exit 1
fi

# return 1 if is mounted otherwise return 0
check_mount() {
    local checkdir=${1}
    if [ -n "$checkdir" ] ; then
    local check=`grep "$checkdir" /proc/mounts`
    if [ -n "$check" ] ; then
	return 1
    fi
    fi
    return 0
}

# We will create 5 testcrash LV in $LVGroupName each with 5GB size
# and format it as ext3
do_lvm_create_testcrash() {
    local lvname=${1:-testcrash}
    local lvsize=${2:-5G}
    local limit=${3:-5}
    local count=1
    while [ "$count" -le "$limit" ]
    do
    if [ ! -h "/dev/${LVGroupName}/${lvname}${count}" ] ; then
	echo "lvcreate -v -n ${lvname}${count} -L ${lvsize} ${LVGroupName} ... ... "
	lvcreate -v -n ${lvname}${count} -L ${lvsize} ${LVGroupName}
	echo "lvcreate -v -n ${lvname}${count} -L ${lvsize} ${LVGroupName} completed!"
	if [ -h "/dev/${LVGroupName}/${lvname}${count}" ] ; then
	echo "mke2fs -F -j /dev/${LVGroupName}/${lvname}${count} ... ... "
	mke2fs -F -j /dev/${LVGroupName}/${lvname}${count}
	echo "mke2fs -F -j /dev/${LVGroupName}/${lvname}${count} completed!"
	else
	echo "/dev/${LVGroupName}/${lvname}${count} not found!"
	fi
    fi
    count=`expr $count + 1`
    done
}

do_lvm_create_remove() {
    # number of loops default is 1
    local loopcountlimit=${1:-1}
    # snapshot size default is 1G
    local snapshotsize=${2:-1G}
    # implement a sleep between create, mount, umount and remove (default is 0 which is no pause)
    local pauseinterval=${3:-0}
    # execute commands after each pause/sleep such as sync or anything that you want to test
    local commands=${4}
    # We filter out snapshot and swap
    local count=0
    if [ -d "/dev/${LVGroupName}" ] ; then
    while [ "$count" -lt "$loopcountlimit" ]
    do
	count=`expr $count + 1`
	echo "${count} ... ... "
	echo "${count} at `date`" >> /tmp/testcrash.log
	for i in `ls /dev/${LVGroupName} | grep -Ev 'snapshot$' | grep -Ev 'swap$'`; do
	if [ -h "/dev/${LVGroupName}/${i}" ] ; then
	    echo -n "lvcreate -s -v -n ${i}-snapshot -L ${snapshotsize} /dev/${LVGroupName}/${i} ... ... "
	    lvcreate -s -v -n ${i}-snapshot -L ${snapshotsize} /dev/${LVGroupName}/${i}
	    echo "done."
	    sleep ${pauseinterval}
	    if [ -n "$commands" ] ; then
	    echo -n "${commands} ... ... "
	    $commands
	    echo "done."
	    fi
	    mkdir -p /mnt/testlvm/${i}
	    if [ -h "/dev/${LVGroupName}/${i}-snapshot" ] ; then
	    check_mount /mnt/testlvm/${i}
	    local ismount=$?
	    if [ "$ismount" -eq 0 ] ; then
		echo -n "mount /dev/${LVGroupName}/${i}-snapshot /mnt/testlvm/${i} ... ... "
		mount /dev/${LVGroupName}/${i}-snapshot /mnt/testlvm/${i}
		echo "done."
		sleep ${pauseinterval}
		if [ -n "$commands" ] ; then
		echo -n "${commands} ... ... "
		$commands
		echo "done."
		fi
	    fi
	    check_mount /mnt/testlvm/${i}
	    local ismount2=$?
	    if [ "$ismount2" -eq 1 ] ; then
		echo -n "umount /mnt/testlvm/${i} ... ... "
		umount /mnt/testlvm/${i}
		echo "done."
		sleep ${pauseinterval}
		if [ -n "$commands" ] ; then
		echo -n "${commands} ... ... "
		$commands
		echo "done."
		fi
	    fi
	    fi
	    rm -rf /mnt/testlvm/${i}
	    echo -n "lvremove -f /dev/${LVGroupName}/${i}-snapshot ... ... "
	    lvremove -f /dev/${LVGroupName}/${i}-snapshot
	    echo "done."
	    sleep ${pauseinterval}
	    if [ -n "$commands" ] ; then
	    echo -n "${commands} ... ... "
	    $commands
	    echo "done."
	    fi
	fi
	done
	rm -fr /mnt/testlvm
    done
    else
    echo "/dev/${LVGroupName} directory not found!"
    exit 1
    fi
}

case $1 in
    setup)    shift
    do_lvm_create_testcrash "$@"
    ;;
    loop)    shift
    do_lvm_create_remove "$@"
    ;;
    *)    cat <<HELP
Usage: $0 loop loopcountlimit snapshotsize pauseinterval commands
Where:
    loopcountlimit is default to 1
    snapshotsize is default to 1G
    pauseinterval is default to 0
    commands is default to none

Example to run with 100 loops without pause/sleep:
    $0 loop 100

Example to run with 100 loops with pause/sleep of 5 seconds:
    $0 loop 100 1G 5

Example to run with 100 loops with snapshot size of 2G instead of 1G:
    $0 loop 100 2G

Example to run with 50 loops, 1G snapshot size, 5 seconds pause and with sync:
command with each pause/sleep
    $0 loop 50 1G 5 sync

Example to run your own commands:
    $0 loop 100 1G 5 "echo hi && sync"

If this is the first time you are running and do not have any LV in your VG, run:
    $0 setup
This will create 5 testcrash LV in your VG with 5GB size each (default)

Usage for setup:
Usage: $0 setup yourtestcrashlvname eachtestcrashsize numberoftestcrash
Where:
    yourtestcrashlvname is default to testcrash
    eachtestcrashsize is default to 5G
    numberoftestcrash is default to 5

If you need more testcrash LV, do something like:
    $0 setup testcrash 5G 10
This will create 10 testcrash LV with 5GB size each.

If you need to setup different name such as testing other than testcrash, do so:
    $0 setup testing
This will create 5 testing LV with 5GB size each.

HELP
    ;;
esac