#!/bin/sh
#defrag v0.01 by Con Kolivas <kernel@kolivas.org
#braindead defrag to rewrite files in order largest to smallest

trap 'abort' 1 2 15

renice 19 $$ > /dev/null

abort()
{
	echo Aborting
	rm -f tmpfile dirlist
	exit 1
}

fail()
{
	echo Failed
	abort
}

declare -i maxsize=`awk '/MemTotal/ {print $2}' /proc/meminfo`
declare -i filesize=0

(( maxsize/= 3))

if [[ -a tmpfile || -a dirlist  ]] ; then
	echo dirlist or tmpfile exists
	abort
fi

find -printf "%p %s\n" | sort -nr +1 | awk '{print $1}' > dirlist
if (( $? )) ; then
	fail
fi

for i in `cat dirlist`
do
	if [[ ! -f $i ]]; then
		continue;
	fi
	filesize=`find $i -printf "%s"`
	# read the file first to cache it in ram if possible
	if (( filesize < maxsize )) ; then
		cat $i > /dev/null
	fi
	cp -a -f $i tmpfile
	if (( $? )) ; then
		fail
	fi
	mv -f tmpfile $i
	if (( $? )) ; then
		fail
	fi
done

rm -f dirlist