Cloning this repository:

git clone git://gitorious.org/freebroid/external_genext2fs.git external_genext2fs
cd external_genext2fs

Add this repository as a remote to an existing local repository:

git remote add external_genext2fs git://gitorious.org/freebroid/external_genext2fs.git
git fetch external_genext2fs
git checkout -b my-local-tracking-branch external_genext2fs/master_or_other_branch