From dc25fb3e4240a23c4e574110ed61ad46628edac7 Mon Sep 17 00:00:00 2001
From: Christian Kellner <christian@kellner.me>
Date: Mon, 16 Dec 2019 16:50:57 +0100
Subject: [PATCH] assembler/qemu: helper to root fs partition

Introduce a method on the PartitionTable that returns the partition
containing the root filesystem. NB: this does not have to be the
first partition (which could be the EFI partition, or something
else), so we have to iterate through the partitions until we find
it.
---
 assemblers/org.osbuild.qemu | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/assemblers/org.osbuild.qemu b/assemblers/org.osbuild.qemu
index 3830f67d..5987db85 100755
--- a/assemblers/org.osbuild.qemu
+++ b/assemblers/org.osbuild.qemu
@@ -236,6 +236,13 @@ class PartitionTable:
         parts_fs = filter(lambda p: p.filesystem is not None, self.partitions)
         return sorted(parts_fs, key=mountpoint_len)
 
+    def partition_containing_root(self) -> Partition:
+        """Return the partition containing the root filesystem"""
+        for p in self.partitions:
+            if p.mountpoint and p.mountpoint == "/":
+                return p
+        return None
+
     def write_to(self, target, sync=True):
         """Write the partition table to disk"""
         # generate the command for sfdisk to create the table
@@ -318,11 +325,8 @@ def install_grub2(image: str, pt: PartitionTable):
     """Install grub2 to image"""
     grub2_core = "/var/tmp/grub2-core.img"
 
-    root_fs_type = "unknown"
-    for p in pt:
-        if p.mountpoint and p.mountpoint == "/":
-            root_fs_type = p.fs_type
-            break
+    root_part = pt.partition_containing_root()
+    root_fs_type = root_part.fs_type or "unknown"
 
     if root_fs_type == "ext4":
         fs_module = "ext2"