From ca1fe71cf9867f22c9265a9b75ed895de515f892 Mon Sep 17 00:00:00 2001
From: Matthew Thode <mthode@mthode.org>
Date: Thu, 17 May 2018 10:50:47 -0500
Subject: [PATCH] Fall back to PARTUUID if UUID returns nothing.

blkid does not always return a UUID when querying partitions (sda2 in my
case).  It does seem to return a PARTUUID though, so use that if needed.

Change-Id: I6f8dbd8fb8a02f6246b7ab00801159544f3288d6
Story: 2002052
Task: 19701
---
 ironic_lib/disk_utils.py            | 14 +++++++++++---
 ironic_lib/tests/test_disk_utils.py | 16 ++++++++++++++++
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/ironic_lib/disk_utils.py b/ironic_lib/disk_utils.py
index 4859fa38..c2764850 100644
--- a/ironic_lib/disk_utils.py
+++ b/ironic_lib/disk_utils.py
@@ -325,10 +325,18 @@ def populate_image(src, dst):
 
 
 def block_uuid(dev):
-    """Get UUID of a block device."""
+    """Get UUID of a block device.
+
+    Try to fetch the UUID, if that fails, try to fetch the PARTUUID.
+    """
     out, _err = utils.execute('blkid', '-s', 'UUID', '-o', 'value', dev,
-                              run_as_root=True,
-                              check_exit_code=[0])
+                              run_as_root=True, check_exit_code=[0])
+    if not out:
+        LOG.debug('Falling back to partition UUID as the block device UUID '
+                  'was not found while examining %(device)s',
+                  {'device': dev})
+        out, _err = utils.execute('blkid', '-s', 'PARTUUID', '-o', 'value',
+                                  dev, run_as_root=True, check_exit_code=[0])
     return out.strip()
 
 
diff --git a/ironic_lib/tests/test_disk_utils.py b/ironic_lib/tests/test_disk_utils.py
index 2b7f8ba1..9281e1c7 100644
--- a/ironic_lib/tests/test_disk_utils.py
+++ b/ironic_lib/tests/test_disk_utils.py
@@ -807,6 +807,22 @@ class OtherFunctionTestCase(base.IronicLibTestCase):
                                              '/dev/fake', run_as_root=True,
                                              use_standard_locale=True)
 
+    @mock.patch.object(utils, 'execute', autospec=True)
+    def test_block_uuid_fallback_to_uuid(self, mock_execute):
+        mock_execute.side_effect = [('', ''),
+                                    ('value', '')]
+        self.assertEqual('value',
+                         disk_utils.block_uuid('/dev/fake'))
+        execute_calls = [
+            mock.call('blkid', '-s', 'UUID', '-o', 'value',
+                      '/dev/fake', check_exit_code=[0],
+                      run_as_root=True),
+            mock.call('blkid', '-s', 'PARTUUID', '-o', 'value',
+                      '/dev/fake', check_exit_code=[0],
+                      run_as_root=True)
+        ]
+        mock_execute.assert_has_calls(execute_calls)
+
 
 @mock.patch.object(utils, 'execute', autospec=True)
 class WholeDiskPartitionTestCases(base.IronicLibTestCase):