make an ext3 partition and mount it.
Code:
dd if=/dev/zero of=/mnt/us/extensions/postgresql/data/data.ext3 bs=1M count=512
mkfs.ext3 /mnt/us/extensions/postgresql/data/data.ext3
tune2fs -i 0 -c 0 /mnt/us/extensions/postgresql/data/data.ext3
mkdir /mnt/us/extensions/postgresql/data/rt
mount -o loop -t ext3 /mnt/us/extensions/postgresql/data/data.ext3 /mnt/us/extensions/postgresql/data/rt