#!/bin/sh

#
# Copyright (c) 2014 EMC Corp.
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# Test vm.overcommit. Variation of overcommit.sh
# Use a swap backed MD disk with the size of 1.2 * hw.usermem.
# Deadlock seen: https://people.freebsd.org/~pho/stress/log/alan007.txt

[ `id -u ` -ne 0 ] && echo "Must be root!" && exit 1
[ `swapinfo | wc -l` -eq 1 ] && exit 0

. ../default.cfg

old=`sysctl -n vm.overcommit`
[ $old -eq 1 ] && exit

size=$((`sysctl -n hw.usermem` / 1024 / 1024))	# in MB
size=$((size + size / 100 * 20))		# 120% of hw.usermem
sysctl vm.overcommit=1
trap "sysctl vm.overcommit=$old" EXIT INT

mount | grep $mntpoint | grep -q /dev/md && umount -f $mntpoint
mdconfig -l | grep -q md$mdstart &&  mdconfig -d -u $mdstart
mdconfig -a -t swap -s ${size}m -u $mdstart
newfs $newfs_flags md$mdstart > /dev/null
mount /dev/md$mdstart $mntpoint

echo "Expect:
   /mnt: write failed, filesystem is full
   dd: /mnt/big.1: No space left on device"

for i in `jot 10`; do
	dd if=/dev/zero of=$mntpoint/big.$i bs=1m  status=none
done
wait

while mount | grep "on $mntpoint " | grep -q /dev/md; do
	umount $mntpoint || sleep 1
done
mdconfig -d -u $mdstart
