kernel-6.1: also provide uncompressed devel files

When using erofs as the root filesystem, we want to avoid other forms
of compression, such as the squashfs used for the kernel development
files.

Include the uncompressed version of these files when the erofs image
feature is set, and override the configuration for the mount unit to
do a simple bind mount instead.

Signed-off-by: Ben Cressey <[email protected]>

packages/kernel-6.1/kernel-6.1.spec

@@ -16,6 +16,9 @@ Source200: check-fips-modules.drop-in.conf.in
 Source201: fipsmodules-x86_64
 Source202: fipsmodules-aarch64
 
+# Adjust kernel-devel mount behavior if not squashfs.
+Source210: var-lib-kernel-devel-lower.mount.drop-in.conf.in
+
 # Bootconfig snippets to adjust the default kernel command line for the platform.
 Source300: bootconfig-aws.conf
 Source301: bootconfig-vmware.conf
@@ -70,10 +73,24 @@ Requires: (%{name}-fips if %{_cross_os}image-feature(fips))
 
 %package devel
 Summary: Configured Linux kernel source for module building
+Requires: (%{name}-devel-squashed if %{_cross_os}image-feature(no-erofs-root-partition))
+Requires: (%{name}-devel-unpacked if %{_cross_os}image-feature(erofs-root-partition))
 
 %description devel
 %{summary}.
 
+%package devel-squashed
+Summary: Configured Linux kernel source for module building (squashed)
+
+%description devel-squashed
+%{summary}.
+
+%package devel-unpacked
+Summary: Configured Linux kernel source for module building (unpacked)
+
+%description devel-unpacked
+%{summary}.
+
 %package archive
 Summary: Archived Linux kernel source for module building
 
@@ -265,6 +282,10 @@ mkdir -p src_squashfs/%{version}
 tar c -T kernel_devel_files | tar x -C src_squashfs/%{version}
 mksquashfs src_squashfs kernel-devel.squashfs ${SQUASHFS_OPTS}
 
+# Create an uncompressed set of kernel-devel files in the standard location.
+install -d %{buildroot}%{_cross_datadir}/bottlerocket/kernel-devel/%{version}
+tar c -T kernel_devel_files | tar x -C %{buildroot}%{_cross_datadir}/bottlerocket/kernel-devel/%{version}
+
 # Create a tarball of the same files, for use outside the running system.
 # In theory we could extract these files with `unsquashfs`, but we do not want
 # to require it to be installed on the build host, and it errors out when run
@@ -300,6 +321,11 @@ for fipsmod in $(cat %{_sourcedir}/fipsmodules-%{_cross_arch}) ; do
   (( i+=1 ))
 done
 
+LOWERPATH=$(systemd-escape --path %{_cross_sharedstatedir}/kernel-devel/.overlay/lower)
+mkdir -p %{buildroot}%{_cross_unitdir}/"${LOWERPATH}.mount.d"
+sed -e 's|PREFIX|%{_cross_prefix}|g' %{S:210} \
+  > %{buildroot}%{_cross_unitdir}/"${LOWERPATH}.mount.d"/no-squashfs.conf
+
 # Install platform-specific bootconfig snippets.
 install -d %{buildroot}%{_cross_bootconfigdir}
 install -p -m 0644 %{S:300} %{buildroot}%{_cross_bootconfigdir}/05-aws.conf
@@ -338,10 +364,16 @@ install -p -m 0644 %{S:302} %{buildroot}%{_cross_bootconfigdir}/05-metal.conf
 
 %files devel
 %dir %{_cross_ksrcdir}
-%{_cross_datadir}/bottlerocket/kernel-devel.squashfs
 %{_cross_kmoddir}/source
 %{_cross_kmoddir}/build
 
+%files devel-squashed
+%{_cross_datadir}/bottlerocket/kernel-devel.squashfs
+
+%files devel-unpacked
+%{_cross_datadir}/bottlerocket/kernel-devel
+%{_cross_unitdir}/*kernel*devel*.mount.d/no-squashfs.conf
+
 %files archive
 %{_cross_datadir}/bottlerocket/kernel-devel.tar.xz
 

packages/kernel-6.1/var-lib-kernel-devel-lower.mount.drop-in.conf.in

@@ -0,0 +1,4 @@
+[Mount]
+What=PREFIX/share/bottlerocket/kernel-devel
+Type=none
+Options=rbind,rshared