[GRUB PARTUUID PATCH V2 2/2] Update grub script template files

[Nicholas Vinson <nvinson234@gmail.com>]

Update grub-mkconfig.in and 10_linux.in to support grub-probe's new
partuuid target.  Update grub.texi documenation.

Signed-off-by: Nicholas Vinson <nvinson234@gmail.com>
---
 docs/grub.texi          | 13 +++++++++++++
 util/grub-mkconfig.in   |  3 +++
 util/grub.d/10_linux.in | 13 +++++++++++--
 3 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/docs/grub.texi b/docs/grub.texi
index 82f6fa4..1f312c6 100644
--- a/docs/grub.texi
+++ b/docs/grub.texi
@@ -1405,6 +1405,19 @@ the Linux kernel, using a @samp{root=UUID=...} kernel parameter.  This is
 usually more reliable, but in some cases it may not be appropriate.  To
 disable the use of UUIDs, set this option to @samp{true}.
 
+@item GRUB_ENABLE_LINUX_PARTUUID
+Normally, when @command{grub-mkconfig} sets the @samp{root=UUID=...} kernel
+parameter, it selects a filesystem UUID.  This works well for Linux systems that
+boot using an initramfs as most implementations support mounting the root
+filesystem this way.  However for Linux systems that do not boot using an
+initramfs, @command{grub-mkconfig} defaults to setting the @samp{root=...}
+kernel parameter to the device name containing the root filesystem.  Setting
+this option to @samp{true} changes the behavior of @command{grub-mkconfig} so
+that it identifies the device containing the root filesystem by the partition
+UUID.  In order to use the @samp{root=PARTUUID=...} kernel parameter, the Linux
+kernel version must be at least 2.6.37 (3.10 for systems using the MSDOS
+partition scheme).
+
 @item GRUB_DISABLE_RECOVERY
 If this option is set to @samp{true}, disable the generation of recovery
 mode menu entries.
diff --git a/util/grub-mkconfig.in b/util/grub-mkconfig.in
index f8496d2..30ead59 100644
--- a/util/grub-mkconfig.in
+++ b/util/grub-mkconfig.in
@@ -134,6 +134,7 @@ fi
 # Device containing our userland.  Typically used for root= parameter.
 GRUB_DEVICE="`${grub_probe} --target=device /`"
 GRUB_DEVICE_UUID="`${grub_probe} --device ${GRUB_DEVICE} --target=fs_uuid 2> /dev/null`" || true
+GRUB_DEVICE_PARTUUID="`${grub_probe} --device ${GRUB_DEVICE} --target=partuuid 2> /dev/null`" || true
 
 # Device containing our /boot partition.  Usually the same as GRUB_DEVICE.
 GRUB_DEVICE_BOOT="`${grub_probe} --target=device /boot`"
@@ -182,6 +183,7 @@ if [ "x${GRUB_ACTUAL_DEFAULT}" = "xsaved" ] ; then GRUB_ACTUAL_DEFAULT="`"${grub
 # override them.
 export GRUB_DEVICE \
   GRUB_DEVICE_UUID \
+  GRUB_DEVICE_PARTUUID \
   GRUB_DEVICE_BOOT \
   GRUB_DEVICE_BOOT_UUID \
   GRUB_FS \
@@ -215,6 +217,7 @@ export GRUB_DEFAULT \
   GRUB_TERMINAL_OUTPUT \
   GRUB_SERIAL_COMMAND \
   GRUB_DISABLE_LINUX_UUID \
+  GRUB_ENABLE_LINUX_PARTUUID \
   GRUB_DISABLE_RECOVERY \
   GRUB_VIDEO_BACKEND \
   GRUB_GFXMODE \
diff --git a/util/grub.d/10_linux.in b/util/grub.d/10_linux.in
index de9044c..71675fa 100644
--- a/util/grub.d/10_linux.in
+++ b/util/grub.d/10_linux.in
@@ -220,8 +220,17 @@ while [ "x$list" != "x" ] ; do
     gettext_printf "Found initrd image: %s\n" "${dirname}/${initrd}" >&2
   elif test -z "${initramfs}" ; then
     # "UUID=" and "ZFS=" magic is parsed by initrd or initramfs.  Since there's
-    # no initrd or builtin initramfs, it can't work here.
-    linux_root_device_thisversion=${GRUB_DEVICE}
+    # no initrd or builtin initramfs, it can't work here.  However, if
+    # GRUB_DEVICE_PARTUUID is not empty we can use that here if
+    # GRUD_DISABLE_LINUX_UUID is not set to true and GRUB_ENABLE_LINUX_PARTUUID
+    # is set to true.
+    if [ "x${GRUB_DISABLE_LINUX_UUID}" != "xtrue" ] \
+        && [ "x${GRUB_DEVICE_PARTUUID}" != "x" ]    \
+        && [ "x${GRUB_ENABLE_LINUX_PARTUUID}" = "xtrue" ] ; then
+        linux_root_device_thisversion="PARTUUID=${GRUB_DEVICE_PARTUUID}"
+    else
+        linux_root_device_thisversion=${GRUB_DEVICE}
+    fi
   fi
 
   if [ "x$is_top_level" = xtrue ] && [ "x${GRUB_DISABLE_SUBMENU}" != xy ]; then
-- 
2.9.2