I'm a newbie... I restored the ubuntu partition from /dev/sda8 to /dev/sda1.... I removed windows partition and installed ubuntu on it. I formatted NTFS partition to reiserfs.
/dev/sda8 was of 8.8G -> It was in reiserfs
/dev/sda1 is 20+ G -> Partitioned to reiserfs
I was able to restore the partition but the "df -h" command shows 8.8 G only instead of 20+G also I cannot use the rest of the disk space.
Googled and got the answer- use resize2fs_reiserfs /dev/sda1
fixed the issue!!