From 2605c6ca952ec8d2a05e7673132c53ed3d3e18ca Mon Sep 17 00:00:00 2001
From: Brandon Philips <brandon@ifup.co>
Date: Mon, 9 Sep 2013 17:47:10 -0700
Subject: [PATCH] feat(vm_image_util): use bind mounts for pxe oem

solid cleanup idea from marineam to use bind mounts instead of copying
to generate the desired root layout.
---
 build_library/vm_image_util.sh | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/build_library/vm_image_util.sh b/build_library/vm_image_util.sh
index b666ef9314..66695a07db 100644
--- a/build_library/vm_image_util.sh
+++ b/build_library/vm_image_util.sh
@@ -366,30 +366,27 @@ _write_dir_to_cpio() {
 _write_squashfs_root() {
     local cpio_target="$1"
     local root_mnt="${VM_TMP_DIR}/rootfs"
-    local root_build="${VM_TMP_DIR}/rootbuild"
+    local oem_mnt="${VM_TMP_DIR}/oem"
     local dst_dir=$(_dst_dir)
     local vmlinuz_name="$(_dst_name ".vmlinuz")"
 
     mkdir -p "${root_mnt}"
-    mkdir -p "${root_build}"
     mkdir -p "${cpio_target}"
 
     # Roll the rootfs into the build dir
     sudo mount -o loop,ro "${TEMP_ROOTFS}" "${root_mnt}"
-    sudo cp -Ra "${root_mnt}"/. "${root_build}"
-    cp "${root_mnt}"/boot/vmlinuz "${dst_dir}/${vmlinuz_name}"
-    sudo umount "${root_mnt}"
 
     # Roll the OEM into the build dir
-    local oem_mnt="${VM_TMP_DIR}/oem"
-    sudo cp -Ra "${oem_mnt}" "${root_build}"
-    sudo rm -R "${VM_TMP_DIR}/oem"
-
+    sudo mount --bind "${oem_mnt}"/usr/share/oem "${root_mnt}"/usr/share/oem
     # Build the squashfs
-    sudo mksquashfs "${root_build}" "${cpio_target}"/newroot.squashfs
-    ls -la ${cpio_target}
+    sudo mksquashfs "${root_mnt}" "${cpio_target}"/newroot.squashfs
 
-    sudo rm -rf "${root_mnt}" "${root_build}"
+    cp "${root_mnt}"/boot/vmlinuz "${dst_dir}/${vmlinuz_name}"
+
+    sudo umount "${root_mnt}"/usr/share/oem
+    sudo umount "${root_mnt}"
+
+    sudo rm -rf "${root_mnt}"
 }
 
 # If a config format is defined write it!