#!/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.
#
# Created by Giam Teck Choon
#

# The LV name and for this case we are using XenGroup
LVGroupName=XenGroup

# 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
}

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=${3:-0}
    # We filter out control, snapshot and swap
    local count=0
    if [ -d "/dev/${LVGroupName}" ] ; then
        while [ "$count" -lt "$loopcountlimit" ]
        do
            count=`expr $count + 1`
            echo "${count} ... ... "
            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 ${pauseinterval}
                    mkdir -p /mnt/testlvm/${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 ${pauseinterval}
                        fi
                        check_mount /mnt/testlvm/${i}
                        local ismount2=$?
                        if [ "$ismount2" -eq 1 ] ; then
                            echo -n "umount /mnt/testlvm/${i} ... ... "
                            umount /mnt/testlvm/${i}
                            echo "done."
                            sleep ${pauseinterval}
                        fi
                    fi
                    rm -rf /mnt/testlvm/${i}
                    echo -n "lvremove -f /dev/${LVGroupName}/${i}-snapshot ... ... "
                    lvremove -f /dev/${LVGroupName}/${i}-snapshot
                    echo "done."
                    sleep ${pauseinterval}
                fi
            done
            rm -fr /mnt/testlvm
        done
    else
        echo "/dev/${LVGroupName} directory not found!"
        exit 1
    fi
}

case $1 in
    loop)    shift
        do_lvm_create_remove "$@"
        ;;
    *)    echo "Usage: $0 loop loopcountlimit(default is 1) snapshotsize(default is 1GB) pauseinterval (default is 0)"
        ;;
esac