Add zdev rules to the initrd for all installations.

Always hook the udev rules that read the `/etc/zfs/zdev.conf` file into the
initrd, even if the system is not using the zfs-initramfs package.

This change ensures that `/dev/disk/zpool` device aliases are ready in time for
`mount` calls early in the init stack.

Amended-by: Darik Horn <dajhorn@vanadac.com>
Closes: dajhorn/pkg-zfs#39
Closes: openzfs/zfs#811

debian/tree/zfs-initramfs/usr/share/initramfs-tools/hooks/zfs

@@ -1,33 +1,20 @@
 #!/bin/sh
 #
-# Add ZFS filesystem capabilities to an initrd through update-initramfs.
+# Add ZoL filesystem capabilities to an initrd, usually for a native ZFS root.
 #
 
+# This hook installs udev rules for ZoL.
+PREREQ="zdev"
 
-# This module depends on these initramfs-tools modules.
-PREREQ="udev"
-
-# ZFS on Linux uses udev for device node creation.
-PREREQ_UDEV_RULES="60-zpool.rules 60-zvol.rules"
+# 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="/sbin/zdb /sbin/zpool /sbin/zfs /sbin/mount.zfs"
 
-# These prerequisites are provided by the zfs package. The zdb utility is not
-# strictly required, but it can be useful at the initramfs recovery prompt.
-COPY_EXEC_LIST=" \
-  /lib/udev/zvol_id \
-  /lib/udev/zpool_id \
-  /sbin/zdb \
-  /sbin/zpool \
-  /sbin/zfs \
-  /sbin/mount.zfs \
-  "
+# These prerequisites are provided by the base system.
+COPY_EXEC_LIST="$COPY_EXEC_LIST /bin/hostname /sbin/blkid"
 
-# These prerequisites are provides by other packages.
-COPY_EXEC_LIST="$COPY_EXEC_LIST \
-  /bin/hostname \
-  /sbin/blkid \
-  "
-
-# Explicitly specify all modules because dependency resolution is unreliable here.
+# Explicitly specify all kernel modules because automatic dependency resolution
+# is unreliable on many systems.
 MANUAL_ADD_MODULES_LIST="zlib_deflate spl zavl zcommon znvpair zunicode zfs"
 
 # Generic result code.
@@ -57,30 +44,13 @@ fi
 . /usr/share/initramfs-tools/hook-functions
 
 mkdir -p "$DESTDIR/etc/"
-mkdir -p "$DESTDIR/lib/udev/rules.d/"
 
 # ZDB uses pthreads for some functions, but the library dependency is not
 # automatically detected. The `find` utility and extended `cp` options are
 # used here because libgcc_s.so could be in a subdirectory of /lib for
 # multi-arch installations.
 cp --target-directory="$DESTDIR" --parents $(find /lib -type f -name libgcc_s.so.1)
 
-
-for ii in $PREREQ_UDEV_RULES
-do
-	if [ -e "/etc/udev/rules.d/$ii" ]
-	then
-		cp -p "/etc/udev/rules.d/$ii" "$DESTDIR/lib/udev/rules.d/"
-	elif [ -e "/lib/udev/rules.d/$ii" ]
-	then
-		cp -p "/lib/udev/rules.d/$ii" "$DESTDIR/lib/udev/rules.d/"
-	else
-		echo "Error: Missing udev rule: $ii"
-		echo "       This file must be in the /etc/udev/rules.d or /lib/udev/rules.d directory."
-		exit 1
-	fi
-done
-
 for ii in $COPY_EXEC_LIST
 do
 	copy_exec "$ii"
@@ -101,8 +71,3 @@ fi
 # The spl package ensures that the /etc/hostid file exists.
 # NB: Commentary in the spl.postinst script.
 cp -p "/etc/hostid" "$DESTDIR/etc/hostid"
-
-if [ -e "/etc/zfs/" ]
-then
-	cp -a "/etc/zfs/" "$DESTDIR/etc/"
-fi

debian/tree/zfsutils/usr/share/initramfs-tools/hooks/zdev

@@ -0,0 +1,62 @@
+#!/bin/sh
+#
+# Add udev rules for ZoL to the initrd.
+#
+
+PREREQ="udev"
+PREREQ_UDEV_RULES="60-zpool.rules 60-zvol.rules"
+COPY_EXEC_LIST="/lib/udev/zvol_id /lib/udev/zpool_id"
+
+# Generic result code.
+RC=0
+
+case $1 in
+prereqs)
+	echo "$PREREQ"
+	exit 0
+	;;
+esac
+
+for ii in $COPY_EXEC_LIST
+do
+	if [ ! -x "$ii" ]
+	then
+		echo "Error: $ii is not executable."
+		RC=2
+	fi
+done
+
+if [ "$RC" -ne 0 ]
+then
+	exit "$RC"
+fi
+
+. /usr/share/initramfs-tools/hook-functions
+
+mkdir -p "$DESTDIR/etc/"
+mkdir -p "$DESTDIR/lib/udev/rules.d/"
+
+for ii in $PREREQ_UDEV_RULES
+do
+	if [ -e "/etc/udev/rules.d/$ii" ]
+	then
+		cp -p "/etc/udev/rules.d/$ii" "$DESTDIR/lib/udev/rules.d/"
+	elif [ -e "/lib/udev/rules.d/$ii" ]
+	then
+		cp -p "/lib/udev/rules.d/$ii" "$DESTDIR/lib/udev/rules.d/"
+	else
+		echo "Error: Missing udev rule: $ii"
+		echo "       This file must be in the /etc/udev/rules.d or /lib/udev/rules.d directory."
+		exit 1
+	fi
+done
+
+for ii in $COPY_EXEC_LIST
+do
+	copy_exec "$ii"
+done
+
+if [ -e "/etc/zfs/" ]
+then
+	cp -a "/etc/zfs/" "$DESTDIR/etc/"
+fi

debian/zfsutils.triggers

@@ -0,0 +1 @@
+activate update-initramfs