Containerfile

# https://gitlab.com/fedora/bootc/examples/-/blob/main/kernel-module/Containerfile
# https://wiki.centos.org/HowTos(2f)BuildingKernelModules.html#Building_a_kernel_module_rpm_package_.28kmod.29
# https://build.opensuse.org/package/show/filesystems:bcachefs:release/bcachefs
# https://download.opensuse.org/repositories/filesystems:/bcachefs:/release/Fedora_43/filesystems:bcachefs:release.repo

# could try quay.io/bootc-devel/fedora-bootc-43-standard
ARG BUILDER_IMAGE=quay.io/fedora/fedora:latest
# Base image for the final stage
ARG BASE_IMAGE=quay.io/fedora/fedora-coreos:stable

FROM ${BASE_IMAGE} AS base

FROM base AS version-query
# We use `rpm` instead of `uname -r` because `uname` will return the host kernel version instead of container kernel version
RUN rpm -qa kernel --queryformat '%{VERSION}-%{RELEASE}.%{ARCH}' | tee /kernel-version.txt
# arch == aarch64 || x86_64
RUN rpm -qa kernel --queryformat '%{ARCH}' | tee /arch.txt
RUN . /etc/os-release && echo "$VERSION_ID" | tee /fedora-version.txt
# can't yet cache packages in /var/cache/rpm-ostree : https://github.com/coreos/rpm-ostree/issues/5453
#RUN rpm-ostree install bcachefs-tools
# cant install old versions of bcachefs-tools from COPR. builds of old versions are only kept for 2 weeks.
#RUN bcachefs version | tee /bcachefs-tools-version.txt

FROM ${BUILDER_IMAGE} AS builder
# ARG TARGETARCH # pre-defined by podman, re-declare here to use in this stage
# TARGETARCH == arm64 || amd64

COPY --from=version-query /kernel-version.txt /kernel-version.txt
#COPY --from=version-query /bcachefs-tools-version.txt /bcachefs-tools-version.txt
COPY --from=version-query /arch.txt /arch.txt
COPY --from=version-query /fedora-version.txt /fedora-version.txt

# avoids the hundreds of xattr and cp errors with dracut when running dnf install
ENV DRACUT_NO_XATTR=1

# cache target has default mode 755 and root:root ownership
RUN --mount=type=cache,target=/var/cache/libdnf5,sharing=locked <<EOF
set -xeuo pipefail
echo "keepcache=True" >> /etc/dnf/dnf.conf
sed -i 's@enabled=1@enabled=0@g' /etc/yum.repos.d/fedora-cisco-openh264.repo
dnf config-manager addrepo --from-repofile=https://download.opensuse.org/repositories/filesystems:/bcachefs:/release/Fedora_$(cat /fedora-version.txt)/filesystems:bcachefs:release.repo
dnf install -y fedora-repos-archive
#dnf copr enable -y ngompa/bcachefs
EOF

RUN --mount=type=cache,target=/var/cache/libdnf5,sharing=locked \
    dnf install -y kernel-$(cat /kernel-version.txt)  kernel-devel-$(cat /kernel-version.txt) openssl

# the kernel module will be built here in dkms postinstall step
# dkms signs module via /lib/modules/6.18.5-200.fc43.aarch64/build/scripts/sign-file , provided by kernel-devel
RUN --mount=type=cache,target=/var/cache/libdnf5,sharing=locked \
    dnf install -y dkms-bcachefs bcachefs-tools

# dkms mktarball bcachefs/1.36.0 -k 6.17.12-300.fc43.aarch64 --binaries-only --archive ./tarball.tar
# in tarball.tar >
# rw-r--r-- root/root      1709 2026-01-14 07:37 ./dkms_main_tree/6.17.11-300.fc43.aarch64/aarch64/module/Module.symvers
# -rw-r--r-- root/root    799668 2026-01-14 07:37 ./dkms_main_tree/6.17.11-300.fc43.aarch64/aarch64/module/bcachefs.ko.xz

WORKDIR /root
RUN --mount=type=cache,target=/var/cache/libdnf5,sharing=locked \
    dnf install -y rpmdevtools
# dnf install -y kernel-rpm-macros
RUN rpmdev-setuptree
RUN <<EOT cat > ~/rpmbuild/SPECS/bcachefs-kmod.spec
%define module_version $(bcachefs version)
%define kernel_version $(cat /kernel-version.txt)
%define rpm_release 1

Name:           bcachefs-kmod-%{kernel_version}
# dashes not allowed in version
Version:        %{module_version}
# ?dist puts .fc43
Release:        %{rpm_release}%{?dist}
Summary:        bcachefs kernel module

License:        GPL-2.0-only
Source0:        %{_sourcedir}/bcachefs.ko.xz

BuildArch:      $(cat /arch.txt)
Requires:       kernel-uname-r = %{kernel_version}

# mandatory
%description
bcachefs v%{module_version} kernel module for kernel %{kernel_version}

%install
install -d %{buildroot}/usr/lib/modules/%{kernel_version}/extra/
install -m 0755 %{SOURCE0} %{buildroot}/usr/lib/modules/%{kernel_version}/extra/bcachefs.ko.xz

install -d %{buildroot}/etc/modules-load.d/
echo "bcachefs" > %{buildroot}/etc/modules-load.d/bcachefs.conf

%post
depmod -a %{kernel_version}

%files
%defattr(644,root,root,755)
/usr/lib/modules/%{kernel_version}/extra/bcachefs.ko.xz
/etc/modules-load.d/bcachefs.conf
EOT

RUN --mount=type=cache,target=/var/cache/libdnf5,sharing=locked <<EOF
set -euo pipefail
cp -pv /var/lib/dkms/bcachefs/$(bcachefs version)/$(cat /kernel-version.txt)/$(cat /arch.txt)/module/bcachefs.ko.xz ~/rpmbuild/SOURCES/
rpmbuild -bb ~/rpmbuild/SPECS/bcachefs-kmod.spec
# Wrote: /root/rpmbuild/RPMS/aarch64/bcachefs-kmod-6.17.12-300.fc43.aarch64-1.36.0-1.fc43.aarch64.rpm
cp -pv /root/rpmbuild/RPMS/$(cat /arch.txt)/*.rpm /root/
# /var/cache/libdnf5/filesystems_bcachefs_release-2a8b1ff6dcb3911b/packages/bcachefs-tools-1.36.0-1.1.aarch64.rpm
cp -pv /var/cache/libdnf5/filesystems_bcachefs_release-*/packages/bcachefs-tools-*.rpm /root/
EOF

FROM base
#COPY --from=version-query /fedora-version.txt /fedora-version.txt
COPY --from=builder /root/*.rpm /tmp/

#WORKDIR /etc/yum.repos.d/
#RUN curl --fail-with-body -O https://copr.fedorainfracloud.org/coprs/ngompa/bcachefs/repo/fedora-43/ngompa-bcachefs-fedora-43.repo
#RUN curl --fail-with-body -O https://download.opensuse.org/repositories/filesystems:/bcachefs:/release/Fedora_$(cat /fedora-version.txt)/filesystems:bcachefs:release.repo
# installing bcachefs-tools from SUSE or COPR repo also tries to install dkms-bcachefs. So just install the plain .rpm file
RUN <<EOF
set -xeuo pipefail
rpm-ostree install /tmp/bcachefs-*.rpm
rm -v /tmp/bcachefs*.rpm
ostree container commit
EOF