BUG: root on BTRFS multi-volume

[Gene Czarcinski <gene@czarc.net>]

grub2 has a problem handling the case where root ("/") resides on a 
BTRFS multi-volume storage.

The patch below corrects the problem.  This has been tested on both real 
and virtual hardware on Fedora 18, Fedora 19, and Fedora 20-Beta.

I submitted this last January but it appears to have fallen through the 
creacks.

Gene

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 From b9ed3e49354f5159d962c083b68cf06723a4aff5 Mon Sep 17 00:00:00 2001
From: Fedora Ninjas <grub2-owner@fedoraproject.org>
Date: Mon, 14 Oct 2013 16:11:00 -0400
Subject: [PATCH] support for multi-device btrfs volume

The current code produces error messages if passed a device
list with multiple devices for a btrfs volume.  It worked OK
for single device btrfs volume.

This has been regression tested with root/boot on a regular
partition, single device VG logical volume, and single
device btrfs volume.

The name was change from device to devices to indicate that it
could be a device list plus the comments were added.
---
  util/grub-mkconfig_lib.in | 7 +++++--
  1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/util/grub-mkconfig_lib.in b/util/grub-mkconfig_lib.in
index b48e2af..d4d6ba0 100644
--- a/util/grub-mkconfig_lib.in
+++ b/util/grub-mkconfig_lib.in
@@ -270,10 +270,13 @@ gettext_printf () {
    printf "$(gettext "$gettext_printf_format")" "$@"
  }
  
+# $1 may be a list of devices separated by blanks.  grub_probe accepts
+# multiple arguments after --device but each device must be in a separate
+# argument.  Hence ${devices} rather than "${devices}".
  uses_abstraction () {
-  device="$1"
+  devices="$1"
  
-  abstraction="`"${grub_probe}" --device "${device}" --target=abstraction`"
+  abstraction="`"${grub_probe}" --device ${devices} --target=abstraction`"
    for module in ${abstraction}; do
      if test "x${module}" = "x$2"; then
        return 0
-- 
1.8.3.1