From e74c31125d2466db7d5a190f924b1abee6094947 Mon Sep 17 00:00:00 2001
From: Colin Watson <cjwatson@ubuntu.com>
Date: Wed, 13 Apr 2011 12:57:26 +0100
Subject: [PATCH] * util/grub.d/10_linux.in: Add rootflags=subvol=<name> if /
 is on a btrfs subvolume. * util/grub.d/20_linux_xen.in: Likewise.

---
 ChangeLog                   | 6 ++++++
 util/grub.d/10_linux.in     | 8 ++++++++
 util/grub.d/20_linux_xen.in | 8 ++++++++
 3 files changed, 22 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index d0269c905..47935890d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2011-04-13  Colin Watson  <cjwatson@ubuntu.com>
+
+	* util/grub.d/10_linux.in: Add rootflags=subvol=<name> if / is on a
+	btrfs subvolume.
+	* util/grub.d/20_linux_xen.in: Likewise.
+
 2011-04-13  Colin Watson  <cjwatson@ubuntu.com>
 
 	Rewrite /proc/self/mountinfo handling to cope with bind-mounts and
diff --git a/util/grub.d/10_linux.in b/util/grub.d/10_linux.in
index 930ce06ef..1dbcad90c 100644
--- a/util/grub.d/10_linux.in
+++ b/util/grub.d/10_linux.in
@@ -51,6 +51,14 @@ else
   LINUX_ROOT_DEVICE=UUID=${GRUB_DEVICE_UUID}
 fi
 
+if [ "x`${grub_probe} --device ${GRUB_DEVICE} --target=fs 2>/dev/null || true`" = xbtrfs ]; then
+  rootsubvol="`make_system_path_relative_to_its_root /`"
+  rootsubvol="${rootsubvol#/}"
+  if [ "x${rootsubvol}" != x ]; then
+    GRUB_CMDLINE_LINUX="rootflags=subvol=${rootsubvol} ${GRUB_CMDLINE_LINUX}"
+  fi
+fi
+
 linux_entry ()
 {
   os="$1"
diff --git a/util/grub.d/20_linux_xen.in b/util/grub.d/20_linux_xen.in
index 858627aa3..a9007603d 100644
--- a/util/grub.d/20_linux_xen.in
+++ b/util/grub.d/20_linux_xen.in
@@ -51,6 +51,14 @@ else
   LINUX_ROOT_DEVICE=UUID=${GRUB_DEVICE_UUID}
 fi
 
+if [ "x`${grub_probe} --device ${GRUB_DEVICE} --target=fs 2>/dev/null || true`" = xbtrfs ]; then
+  rootsubvol="`make_system_path_relative_to_its_root /`"
+  rootsubvol="${rootsubvol#/}"
+  if [ "x${rootsubvol}" != x ]; then
+    GRUB_CMDLINE_LINUX="rootflags=subvol=${rootsubvol} ${GRUB_CMDLINE_LINUX}"
+  fi
+fi
+
 linux_entry ()
 {
   os="$1"