libext2fs: Add undo I/O manager

This I/O manager saves the contents of the location being overwritten
to a tdb database. This helps in undoing the changes done to the
file system.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
3 files changed