How to convert ext2 to ext3 file system?

■ Requirement : How to convert ext2 to ext3 file system
■ OS Environment : Linux[RHEL, Centos]
■ Application: tune2fs
■ Implementation Steps : 

       The ext2 or second extended filesystem is a file system for the Linux kernel, and the ext3 is a journaled file system. The ext3’s main advantage over ext2 is journaling which improves reliability and eliminates the need to check the file system after an unclean shutdown. Journaling process file system log convert file system during disk, if any problem arise it will be reconstructed it will be done by tune2fs tune to ext3 file system,While the power failure occur, Journalism File system restore pre-crash data store on the disk. It will also restore unsaved data.

1. unmount hda1 and tune it by journel like :

2.  Enable journalling : 

$ tune2fs -c 0 -i 30 -j /dev/hda1

3. then mount it.

NOTE :
c : number of mounts after which the filesystem will be checked by e2fsck. If it's is 0 or -1, the number of times the filesystem is mounted will be disregarded by e2fsck and the kernel
i : Adjust the maximal time between two filesystem checks. Use it with c option.