Revert to snapshot feature in Ext4 file system

by harshad for The Fedora Project

In today's world, large number of packages are downloaded and installed. Considering this scenario there is a need to have a feature that would rollback the system to a state before the package was installed. The snapshots feature in a file system can be effectively used for the same. Yum currently has support for doing snapshots in btrfs before starting a transaction. It would be a good idea to add support for Ext4 snapshots in yum.