Use kpartx option to update partition mappings

Fix cases of 'mkfs' failing because the partitions never showed up. Partition
mappings will now be updated instead of just adding them with 'kpartx'. That
means that 'kpartx' will also remove devmappings for deleted partitions.

Traceback of failing mkfs call:

2020-05-11 22:03:25.523 | INFO diskimage_builder.block_device.utils [-] Calling [sudo sync]
2020-05-11 22:03:25.539 | INFO diskimage_builder.block_device.utils [-] Calling [sudo kpartx -avs /dev/loop0]
2020-05-11 22:03:25.581 | INFO diskimage_builder.block_device.utils [-] Calling [sudo mkfs -t ext4 -i 4096 -J size=64 -L cloudimg-rootfs -U 21c6f9eb-4d52-4e5c-b9b7-796735de8909 -q /dev/mapper/loop0p1]
2020-05-11 22:03:25.700 | ERROR diskimage_builder.block_device.blockdevice [-] Create failed; rollback initiated
2020-05-11 22:03:25.700 | Traceback (most recent call last):
2020-05-11 22:03:25.700 |   File "/home/zuul/dib/lib/python3.6/site-packages/diskimage_builder/block_device/blockdevice.py", line 406, in cmd_create
2020-05-11 22:03:25.700 |     node.create()
2020-05-11 22:03:25.700 |   File "/home/zuul/dib/lib/python3.6/site-packages/diskimage_builder/block_device/level2/mkfs.py", line 133, in create
2020-05-11 22:03:25.700 |     exec_sudo(cmd)
2020-05-11 22:03:25.700 |   File "/home/zuul/dib/lib/python3.6/site-packages/diskimage_builder/block_device/utils.py", line 143, in exec_sudo
2020-05-11 22:03:25.700 |     raise e
2020-05-11 22:03:25.700 | diskimage_builder.block_device.exception.BlockDeviceSetupException: exec_sudo failed
2020-05-11 22:03:25.700 | INFO diskimage_builder.block_device.level0.localloop [-] loopdev detach
2020-05-11 22:03:25.701 | INFO diskimage_builder.block_device.utils [-] Calling [sudo losetup -d /dev/loop0]
2020-05-11 22:03:25.732 | INFO diskimage_builder.block_device.level0.localloop [-] Remove image file [/tmp/dib_image.muyw7t1h/image0.raw]
2020-05-11 22:03:25.734 | ERROR diskimage_builder.block_device.blockdevice [-] Rollback complete, exiting
2020-05-11 22:03:25.740 | Traceback (most recent call last):
2020-05-11 22:03:25.740 |   File "/home/zuul/dib/bin/dib-block-device", line 8, in <module>
2020-05-11 22:03:25.740 |     sys.exit(main())
2020-05-11 22:03:25.740 |   File "/home/zuul/dib/lib/python3.6/site-packages/diskimage_builder/block_device/cmd.py", line 120, in main
2020-05-11 22:03:25.740 |     return bdc.main()
2020-05-11 22:03:25.740 |   File "/home/zuul/dib/lib/python3.6/site-packages/diskimage_builder/block_device/cmd.py", line 115, in main
2020-05-11 22:03:25.740 |     self.args.func()
2020-05-11 22:03:25.740 |   File "/home/zuul/dib/lib/python3.6/site-packages/diskimage_builder/block_device/cmd.py", line 36, in cmd_create
2020-05-11 22:03:25.740 |     self.bd.cmd_create()
2020-05-11 22:03:25.740 |   File "/home/zuul/dib/lib/python3.6/site-packages/diskimage_builder/block_device/blockdevice.py", line 406, in cmd_create
2020-05-11 22:03:25.740 |     node.create()
2020-05-11 22:03:25.740 |   File "/home/zuul/dib/lib/python3.6/site-packages/diskimage_builder/block_device/level2/mkfs.py", line 133, in create
2020-05-11 22:03:25.740 |     exec_sudo(cmd)
2020-05-11 22:03:25.740 |   File "/home/zuul/dib/lib/python3.6/site-packages/diskimage_builder/block_device/utils.py", line 143, in exec_sudo
2020-05-11 22:03:25.740 |     raise e
2020-05-11 22:03:25.740 | diskimage_builder.block_device.exception.BlockDeviceSetupException: exec_sudo failed

Change-Id: I374f7f22f9e93ef35eb5813712ca59e75f0733e8
Related-Bug: #1698337

diskimage_builder/block_device/level1/partitioning.py

@@ -206,7 +206,7 @@ class Partitioning(PluginBase):
         # now all the partitions are created, get device-mapper to
         # mount them
         if not os.path.exists("/.dockerenv"):
-            exec_sudo(["kpartx", "-avs", self.device_path])
+            exec_sudo(["kpartx", "-uvs", self.device_path])
         else:
             # If running inside Docker, make our nodes manually,
             # because udev will not be working. kpartx cannot run in

diskimage_builder/block_device/tests/test_gpt.py

@@ -70,7 +70,7 @@ class TestGPT(tc.TestGraphGeneration):
         cmd_sequence = [
             mock.call(parted_cmd),
             mock.call(['sync']),
-            mock.call(['kpartx', '-avs', '/dev/loopX'])
+            mock.call(['kpartx', '-uvs', '/dev/loopX'])
         ]
         self.assertEqual(mock_exec_sudo.call_count, len(cmd_sequence))
         mock_exec_sudo.assert_has_calls(cmd_sequence)

diskimage_builder/block_device/tests/test_lvm.py

@@ -512,7 +512,7 @@ class TestLVM(tc.TestGraphGeneration):
                 mock.call.create_mbr(),
                 # now mount partitions
                 mock.call.sudo_part(['sync']),
-                mock.call.sudo_part(['kpartx', '-avs', '/dev/fake/image0']),
+                mock.call.sudo_part(['kpartx', '-uvs', '/dev/fake/image0']),
                 # now create lvm environment
                 mock.call.sudo_lvm(['pvcreate', '/dev/fake/root', '--force']),
                 mock.call.sudo_lvm(

releasenotes/notes/block-device-update-partition-table-eb4ff077f90dfb19.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - Fix cases of 'mkfs' failing because the partitions never showed up.
+    Partition mappings will now be updated instead of just adding them with
+    'kpartx'. That means that 'kpartx' will also remove devmappings for deleted
+    partitions.