[G Tablet Android Development] Chenglu:
modify init.rc for mount ext4 /data

you must have tune2fs mkfs.ext4 e2fsck binary file.

#!/system/bin/sh

##get highest priority
/system/bin/renice -20 -r -g $$
ECHO_TARGET=/misc/inandop.log
BUSYBOX="/system/bin/busybox"

#data2loop by xiaolu
echo "try data2loop" >> $ECHO_TARGET

if [ "`$BUSYBOX df /dev/loop0 | grep loop`" != "" } ; then
exit 0
fi

$BUSYBOX ln -s /dev/block/loop0 /dev/loop0
$BUSYBOX ln -s /dev/block/loop1 /dev/loop1
$BUSYBOX ln -s /dev/block/loop2 /dev/loop2
$BUSYBOX ln -s /dev/block/loop3 /dev/loop3
$BUSYBOX ln -s /dev/block/loop4 /dev/loop4
$BUSYBOX ln -s /dev/block/loop5 /dev/loop5
$BUSYBOX ln -s /dev/block/loop6 /dev/loop6
$BUSYBOX ln -s /dev/block/loop7 /dev/loop7

if [ ! -e /data/system.firstrun.finish ];
then
# first run data not create do nothing, data2loop after reboot
#/system/bin/mkfs.ext4 -b 4096 -m 0 -F -L userdata /dev/block/mmcblk3p2
#/system/bin/tune2fs -o journal_data_writeback /dev/block/mmcblk3p2
#/system/bin/e2fsck /dev/block/mmcblk3p2
#/system/bin/tune2fs -O ^has_journal /dev/block/mmcblk3p2
$BUSYBOX mkdir /data/anr
$BUSYBOX touch /data/system.firstrun.finish
exit 0;
fi
$BUSYBOX umount /cache
echo "0" > /data/misc/screen_lock_status
$BUSYBOX chown 1000.1000 /data/misc/screen_lock_status
$BUSYBOX chmod 644 /data/misc/screen_lock_status

$BUSYBOX mkdir /mnt/asec/extdata
/system/bin/tune2fs -o journal_data_writeback /dev/block/mmcblk3p2
$BUSYBOX mount -t ext4 -o remount,barrier=0,nobh,nouser_xattr,errors=continue,noatime,nodiratime,nosuid,nodev /dev/block/mmcblk3p2 /data
result=$?
echo "mount mmcblk3p2:$result" >> $ECHO_TARGET
$BUSYBOX chown 1000.1000 /data
$BUSYBOX chmod 771 /data
echo "+++Need create loopback device for data, please wait... " >> $ECHO_TARGET
if [ ! -e /data/data2loop.finish ];
then
if [ -e /dev/block/mmcblk3p3 ];
then
echo "+++Found mmcblk3p3, will use it for /data/data, create ext4 fs on it now..." >> $ECHO_TARGET
/system/bin/mkfs.ext4 -b 4096 -m 0 -F -L extdata /dev/block/mmcblk3p3
/system/bin/tune2fs -o journal_data_ordered /dev/block/mmcblk3p3
/system/bin/e2fsck -y -v -f /dev/block/mmcblk3p3
#/system/bin/tune2fs -O has_journal /dev/block/mmcblk3p3
/system/bin/tune2fs -O ^has_journal /dev/block/mmcblk3p3
$BUSYBOX mount -t ext4 -o loop,commit=5,barrier=1,nouser_xattr,errors=continue,noatime,nodiratime,nosuid,nodev /dev/block/mmcblk3p3 /mnt/asec/extdata
result=$?
echo "mount /dev/block/mmcblk3p3:$result" >> $ECHO_TARGET
else
echo "+++Need create 512M ext2 loopback device for data, please wait... " >> $ECHO_TARGET
$BUSYBOX dd if=/dev/zero of=/data/ext2 bs=1048576 count=512
$BUSYBOX mke2fs -m 0 -F -L datadata /data/ext2
echo "+++Loopback device create done... " >> $ECHO_TARGET
$BUSYBOX mount -o loop,errors=continue,noatime,nodiratime,nosuid,nodev /data/ext2 /mnt/asec/extdata

fi
$BUSYBOX chown 1000.1000 /mnt/asec/extdata
$BUSYBOX chmod 771 /mnt/asec/extdata
for i in data app-private anr ; do
if [ ! -d /mnt/asec/extdata/$i ] ; then
$BUSYBOX mkdir /mnt/asec/extdata/$i;
fi

$BUSYBOX chown 1000.1000 /mnt/asec/extdata/$i;
$BUSYBOX chmod 771 /mnt/asec/extdata/$i;

#if [ ! -h /data/$i ] ; then
$BUSYBOX cp -a /data/$i /mnt/asec/extdata/;
$BUSYBOX rm -rf /data/$i;
$BUSYBOX ln -s /mnt/asec/extdata/$i /data/$i;
result=$?
echo "ln -s:$result" >> $ECHO_TARGET
#fi
done

$BUSYBOX umount /mnt/asec/extdata
$BUSYBOX touch /data/data2loop.finish
fi

if [ -e /dev/block/mmcblk3p3 ];
then
/system/bin/e2fsck -y -v -f /dev/block/mmcblk3p3
#/system/bin/tune2fs -O ^has_journal /dev/block/mmcblk3p3
/system/bin/tune2fs -o journal_data_writeback /dev/block/mmcblk3p3
$BUSYBOX mknod /dev/loop0 b 7 0
$BUSYBOX losetup /dev/loop0 /dev/block/mmcblk3p3
#$BUSYBOX mount -t ext4 -o sync,commit=5,barrier=1,nouser_xattr,errors=continue,noatime,nodiratime,nosuid,nodev /dev/loop0 /mnt/asec/extdata
$BUSYBOX mount -t ext4 -o barrier=1,nouser_xattr,errors=continue,noatime,nodiratime,nosuid,nodev /dev/loop0 /mnt/asec/extdata
result=$?
echo "mount /dev/loop1:$result" >> $ECHO_TARGET
else
/system/bin/e2fsck -y -v -f /data/ext2
$BUSYBOX mount -o loop,errors=continue,noatime,nodiratime,nosuid,nodev /data/ext2 /mnt/asec/extdata
fi

$BUSYBOX chown 1000.1000 /mnt/asec/extdata
$BUSYBOX chmod 771 /mnt/asec/extdata
$BUSYBOX mkdir /data/cache
$BUSYBOX mount -o bind /data/cache /cache
$BUSYBOX chmod 777 /cache
sync;
exit 0;