sys-apps/coreutils: add check for running zfs(-kmod) version in coreutils 9

We need to make sure people reboot to avoid data corruption, not just
upgrade the module but fail to restart.

Bug: https://bugs.gentoo.org/815469
Signed-off-by: Sam James <sam@gentoo.org>

sys-apps/coreutils/coreutils-9.0-r1.ebuild

@@ -58,6 +58,43 @@ RDEPEND+="
 	!<app-forensics/tct-1.18-r1
 	!<net-fs/netatalk-2.0.3-r4"
 
+pkg_pretend() {
+	if has_version sys-fs/zfs; then
+		einfo "Checking for compatible ZFS version"
+
+		local kmodv minver
+		kmodv="$(grep kmod <(zfs -V 2>/dev/null))"
+		# Convert zfs-kmod-2.1.1-r3-gentoo -> 2.1.1-r3
+		kmodv="${kmodv//zfs-kmod-}"
+		kmodv="${kmodv%%-gentoo}"
+
+		minver="$(ver_cut 2 ${kmodv})"
+		local diemsg=$(cat <<-EOF
+			Attempted installation of ${P} on unsupported version of zfs-kmod!
+			Please reboot to a newer version of zfs-kmod first:
+			zfs-kmod >=2.0.7 or zfs-kmod >=2.1.1-r3
+		EOF
+		)
+
+		case "${minver}" in
+			# 2.0.x
+			0)
+				ver_test "${kmodv}" -lt 2.0.7 && die "${diemsg}"
+				;;
+			# 2.1.x
+			1)
+				ver_test "${kmodv}" -lt 2.1.1-r3 && die "${diemsg}"
+				;;
+			# 0.8.x/9999
+			*)
+				# We can't really cover this case realistically
+				# 9999 is too hard to check and 0.8.x isn't being supported anymore.
+				;;
+		esac
+	fi
+
+}
+
 pkg_setup() {
 	if use test ; then
 		python-any-r1_pkg_setup