This patch adds a "features.aufs2_1" to the aufs-2.1 patch for Linux
2.6.37 to prevent aufs2_1 and aufs2_1_util from being options for
kernels without an aufs 2.1 patch. There were several Hydra build
failures as a result of attempting to build aufs2.1 against older
kernels.
svn path=/nixpkgs/trunk/; revision=26597
* My motivation for this patch is that kernels < 2.6.36 contain an
e1000e that does not support the ethernet card that is part of the
chipset for the second-generation Core-i Intel CPUs, so in order
to have a more useful livecd I needed to get aufs working with a
newer kernel, and 2.6.37 is the latest kernel with an official
aufs release.
* All sources are downloaded with fetchgit. This is because the aufs
upstream doesn't provide release tarballs, they just add a tag to
their git tree for an official release.
* The make target for the aufs2.1 headers uses a Makefile in the
kernel build directory that requires that unifdef be in the
scripts/ subdirectory of the build directory. The way I've dealt
with this here is by adding "make $makeFlags -C scripts unifdef"
to the postBuild in the kernel builder. Since the builder is used
by all kernel versions, this will require rebuilding every kernel
and kernel-dependent package if the patch is accepted, so one
alternative I thought of would be to create a fake kernel build
directory where everything is symlinked to the real build
directory except scripts/, which is first copied and then make
unifdef is run before building aufs2.1. If that more complicated
solution is preferred, or if anyone has ideas for another one, I
can do that and submit a new patch.
* The patch was tested by building a livecd ISO that uses it, then
running the ISO from within virtualbox and installing aufs2.1-util
from within the livecd environment.
* The livecd was built using installation-cd-minimal.nix, with two
changes to the Nixos tree:
1. boot.kernelPackages = pkgs.linuxPackages_2_6_37 was added to
profiles/minimal.nix
2. config.boot.kernelPackages.aufs2 was changed to
config.boot.kernelPackages.aufs2_1 in iso-image.nix
I would have preferred to keep all changes within
profiles/minimal.nix, but I couldn't figure out how to override
iso-image.nix's definition of boot.extraModulePackages. Livecds
that use an older kernel can't be built with this iso-image.nix,
since we don't have aufs2.1 for them (just aufs2). If someone can
point me to how I can override things set in iso-image.nix, I'd
appreciate it.
make -C scripts unifdef compiles the unifdef application in the
scripts/ directory, and when Nix copies over the build tree to
$out/lib/modules/$version/build for kernel modules to reference, it
copies over all of scripts/ except the .o files. I can't speak for
other kernel versions, but at the least for 2.6.37.1 unifdef is not
built by default. If you look at the Makefile in scripts, unifdef is
listed under a comment saying that the following programs are only
built on-demand.
svn path=/nixpkgs/trunk/; revision=26548
