[RFC] 'Fixes' for initramfs creation

zfs-functions is needed, copy that to /etc/zfs/

The zfs hook that copies files will error on critical files.  The
argument for this is we do not want to create a non-functional
initramfs.

Some files are optional, those we do silently ignore

contrib/initramfs/Makefile.am

@@ -21,3 +21,7 @@ install-initrdSCRIPTS: $(EXTRA_DIST)
 	  cp $(top_srcdir)/etc/init.d/zfs \
 	    $(DESTDIR)$(DEFAULT_INITCONF_DIR)/; \
 	fi
+	if [ -f etc/init.d/zfs-functions ]; then \
+	  cp $(top_srcdir)/etc/init.d/zfs-functions \
+	    $(DESTDIR)$(initrddir)/etc/zfs/zfs-functions \
+	fi

contrib/initramfs/hooks/zfs.in

@@ -3,19 +3,24 @@
 # Add ZoL filesystem capabilities to an initrd, usually for a native ZFS root.
 #
 
+# fail on errors; this might be annoying but for now it's more
+# important to fail during initramfs creation where we can do
+# something about it, vs after a boot when we can't
+set -eu
+
 # This hook installs udev rules for ZoL.
 PREREQ="zdev"
 
 # These prerequisites are provided by the zfsutils package. The zdb utility is
 # not strictly required, but it can be useful at the initramfs recovery prompt.
 COPY_EXEC_LIST="@sbindir@/zdb @sbindir@/zpool @sbindir@/zfs"
 COPY_EXEC_LIST="$COPY_EXEC_LIST @mounthelperdir@/mount.zfs @udevdir@/vdev_id"
-COPY_FILE_LIST="/etc/hostid @sysconfdir@/zfs/zpool.cache"
-COPY_FILE_LIST="$COPY_FILE_LIST @sysconfdir@/default/zfs"
 COPY_FILE_LIST="$COPY_FILE_LIST @sysconfdir@/zfs/zfs-functions"
-COPY_FILE_LIST="$COPY_FILE_LIST @sysconfdir@/zfs/vdev_id.conf"
 COPY_FILE_LIST="$COPY_FILE_LIST @udevruledir@/69-vdev.rules"
 
+# These are not required
+OPTIONAL_FILE_LIST="/etc/hostid @sysconfdir@/default/zfs @sysconfdir@/zfs/vdev_id.conf"
+
 # These prerequisites are provided by the base system.
 COPY_EXEC_LIST="$COPY_EXEC_LIST /usr/bin/dirname /bin/hostname /sbin/blkid"
 COPY_EXEC_LIST="$COPY_EXEC_LIST /usr/bin/env"
@@ -66,6 +71,15 @@ do
 done
 
 for ii in $COPY_FILE_LIST
+do
+	dir=$(dirname "$ii")
+	[ -d "$dir" ] && mkdir -p "$DESTDIR/$dir"
+	[ -f "$ii" ] && cp -p "$ii" "$DESTDIR/$ii"
+	# error if missing
+	[ -e "$ii" ]
+done
+
+for ii in $OPTIONAL_FILE_LIST
 do
 	dir=$(dirname "$ii")
 	[ -d "$dir" ] && mkdir -p "$DESTDIR/$dir"