$ git clone -n https://gitee.com/src-opencloudos-rpms/libb2.git /var/lib/mock/dist-oc9-build-59283-16463/root/chroot_tmpdir/scmroot/libb2
Cloning into '/var/lib/mock/dist-oc9-build-59283-16463/root/chroot_tmpdir/scmroot/libb2'...
$ git fetch origin oc9:KOJI_FETCH_HEAD
From https://gitee.com/src-opencloudos-rpms/libb2
 * [new branch]      oc9        -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ce9e595 import libb2-0.98.1-2.tl4