The ext2 or second extended file system is a file system for the Linux kernel. ext2 is not a journaling file system, whereas, ext3 provides journaling and is almost completely compatible with ext2. Ext3 (Third Extended file system in Linux). Here is the process to convert ext2 to ext3. You should have e2fsprogs packages installed on you machine to do the convertion.
Command for converting :
# tune2fs -j /dev/hda7
This adds journaling feature to ext2 and makes it ext3. Make sure this filesystem is not mounted. You can verify this by using tune2fs -l.
# tune2fs -l /dev/hda7 | grep features
Filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery sparse_super