config/rootfs: support NFSv4 in debos initramfs

config/rootfs/debos/overlays/nfs-initramfs/etc/initramfs-tools/hooks/zz-kernelci-nfs

@@ -0,0 +1,24 @@
+#!/bin/sh
+
+PREREQ="klibc-utils"
+
+prereqs()
+{
+	echo "$PREREQ"
+}
+
+case "$1" in
+prereqs)
+	prereqs
+	exit 0
+	;;
+esac
+
+# shellcheck source=/dev/null
+. /usr/share/initramfs-tools/hook-functions
+
+copy_exec /usr/lib/kernelci/mount.nfs /usr/sbin/mount.nfs
+
+# Replace klibc's NFSv2/v3-only helper after its hook has installed it.
+rm -f "${DESTDIR}/bin/nfsmount" "${DESTDIR}/usr/bin/nfsmount"
+copy_file script /usr/lib/kernelci/nfsmount /bin/nfsmount

config/rootfs/debos/overlays/nfs-initramfs/usr/lib/kernelci/nfsmount

@@ -0,0 +1,100 @@
+#!/bin/sh
+
+# Compatibility wrapper for initramfs-tools.  Its NFS boot script calls the
+# klibc nfsmount interface using one or more "-o options" pairs.  Collect those
+# options for mount.nfs and translate LAVA's legacy v4.x spelling.
+#
+# Replacing klibc's NFSv2/v3-only nfsmount with mount.nfs follows the workaround
+# discussed in Debian bug #409271.  The argument translation here is needed for
+# the initramfs-tools call interface and KernelCI's LAVA boot arguments.
+# https://bugs.debian.org/409271
+
+normalize_options()
+{
+	input=$1
+	output=
+
+	while [ -n "$input" ]; do
+		case "$input" in
+		*,*)
+			option=${input%%,*}
+			input=${input#*,}
+			;;
+		*)
+			option=$input
+			input=
+			;;
+		esac
+
+		case "$option" in
+		v4)
+			option=vers=4
+			;;
+		v4.0)
+			option=vers=4.0
+			;;
+		v4.1)
+			option=vers=4.1
+			;;
+		v4.2)
+			option=vers=4.2
+			;;
+		esac
+
+		if [ -n "$output" ]; then
+			output="$output,$option"
+		else
+			output=$option
+		fi
+	done
+
+	printf '%s' "$output"
+}
+
+mount_options=
+mount_source=
+mount_target=
+
+while [ "$#" -gt 0 ]; do
+	case "$1" in
+	-o)
+		shift
+		if [ "$#" -eq 0 ]; then
+			echo "nfsmount: option requires an argument -- 'o'" >&2
+			exit 1
+		fi
+		options=$(normalize_options "$1")
+		if [ -n "$mount_options" ]; then
+			mount_options="$mount_options,$options"
+		else
+			mount_options=$options
+		fi
+		;;
+	-*)
+		echo "nfsmount: unsupported option '$1'" >&2
+		exit 1
+		;;
+	*)
+		if [ -z "$mount_source" ]; then
+			mount_source=$1
+		elif [ -z "$mount_target" ]; then
+			mount_target=$1
+		else
+			echo "nfsmount: too many paths" >&2
+			exit 1
+		fi
+		;;
+	esac
+	shift
+done
+
+if [ -z "$mount_source" ] || [ -z "$mount_target" ]; then
+	echo "nfsmount: need a server path and mount point" >&2
+	exit 1
+fi
+
+if [ -n "$mount_options" ]; then
+	exec /usr/sbin/mount.nfs -o "$mount_options" "$mount_source" "$mount_target"
+else
+	exec /usr/sbin/mount.nfs "$mount_source" "$mount_target"
+fi

config/rootfs/debos/rootfs.yaml

@@ -174,6 +174,10 @@ actions:
     command: xz -9 -T0 -f ${ARTIFACTDIR}/{{ $basename -}}/rootfs.ext4
     postprocess: true
 
+  - action: overlay
+    description: Add NFSv4 initramfs mount helper
+    source: overlays/nfs-initramfs
+
   - action: run
     description: update-initramfs step
     chroot: true

config/rootfs/debos/scripts/create_initrd_ramdisk.sh

@@ -1,5 +1,7 @@
 #!/bin/bash
 
+set -euo pipefail
+
 patch -p1 << 'EOF'
 --- a/usr/share/initramfs-tools/scripts/nfs-premount/wait_ethernet	1970-01-01 02:00:00.000000000 +0200
 +++ b/usr/share/initramfs-tools/scripts/nfs-premount/wait_ethernet	2022-11-25 12:38:46.037498198 +0200
@@ -29,9 +31,61 @@ EOF
 
 chmod +x /usr/share/initramfs-tools/scripts/nfs-premount/wait_ethernet
 
+nfs_packages_before=$(mktemp)
+dpkg-query -W -f='${binary:Package}\t${db:Status-Status}\n' \
+  | sed -n 's/\tinstalled$//p' \
+  | sort -u > "$nfs_packages_before"
+
+# mount.nfs only needs libtirpc and its shared-library dependencies.  Extract
+# the helper without installing nfs-common, whose unrelated device-mapper hook
+# would otherwise make the initramfs larger.
+if ! dpkg-query -W -f='${db:Status-Status}' libtirpc3t64 2>/dev/null \
+    | grep -qx installed; then
+  DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
+    libtirpc3t64
+fi
+nfs_package_dir=$(mktemp -d)
+chown _apt:root "$nfs_package_dir"
+(
+  cd "$nfs_package_dir"
+  apt-get download nfs-common
+)
+nfs_common_deb=$(find "$nfs_package_dir" -maxdepth 1 -type f \
+  -name 'nfs-common_*.deb' -print -quit)
+if [[ -z "$nfs_common_deb" ]]; then
+  echo "Unable to download nfs-common" >&2
+  exit 1
+fi
+dpkg-deb --extract "$nfs_common_deb" "$nfs_package_dir/root"
+install -m 0755 "$nfs_package_dir/root/usr/sbin/mount.nfs" \
+  /usr/lib/kernelci/mount.nfs
+rm -rf -- "$nfs_package_dir"
+
 KVER=min
 
 # update-initramfs uses kernel config to decide how to compress ramdisk
 echo "CONFIG_RD_GZIP=y" > /boot/config-$KVER
 
 update-initramfs -c -k $KVER
+
+# These files are only needed while constructing the initramfs.
+rm -f /etc/initramfs-tools/hooks/zz-kernelci-nfs \
+  /usr/lib/kernelci/nfsmount \
+  /usr/lib/kernelci/mount.nfs
+rmdir --ignore-fail-on-non-empty /usr/lib/kernelci
+
+nfs_packages_after=$(mktemp)
+nfs_packages_remove_file=$(mktemp)
+dpkg-query -W -f='${binary:Package}\t${db:Status-Status}\n' \
+  | sed -n 's/\tinstalled$//p' \
+  | sort -u > "$nfs_packages_after"
+comm -13 "$nfs_packages_before" "$nfs_packages_after" \
+  > "$nfs_packages_remove_file"
+mapfile -t nfs_packages_to_remove < "$nfs_packages_remove_file"
+rm -f "$nfs_packages_before" "$nfs_packages_after" \
+  "$nfs_packages_remove_file"
+if ((${#nfs_packages_to_remove[@]})); then
+  DEBIAN_FRONTEND=noninteractive apt-get purge -y \
+    "${nfs_packages_to_remove[@]}"
+fi
+apt-get clean