Merge lp:~blake-rouse/maas/fix-1597787-2.0 into lp:maas/2.0

[Blake Rouse]

Send size with the extended partition for MBR partition tables.

Backport: https://code.launchpad.net/~blake-rouse/maas/fix-1597787/+merge/298950

[Blake Rouse (blake-rouse)]

Backport, self-review.

review: Approve

=== modified file 'src/maasserver/preseed_storage.py'
--- src/maasserver/preseed_storage.py	2016-03-28 13:54:47 +0000
+++ src/maasserver/preseed_storage.py	2016-07-03 15:21:41 +0000
@@ -9,13 +9,16 @@
 
 from operator import attrgetter
 
+from django.db.models import Sum
 from maasserver.enum import (
     FILESYSTEM_GROUP_TYPE,
     FILESYSTEM_TYPE,
     PARTITION_TABLE_TYPE,
 )
+from maasserver.models.partition import Partition
 from maasserver.models.partitiontable import (
     INITIAL_PARTITION_OFFSET,
+    PARTITION_TABLE_EXTRA_SPACE,
     PREP_PARTITION_SIZE,
 )
 from maasserver.models.physicalblockdevice import PhysicalBlockDevice
@@ -287,16 +290,39 @@
             # Fifth partition on an MBR partition, must add the extend
             # partition operation. So the remaining partitions can be added.
             if partition_number == 5:
+                # Calculate the remaining size of the disk available for the
+                # extended partition.
+                extended_size = block_device.size - PARTITION_TABLE_EXTRA_SPACE
+                previous_partitions = Partition.objects.filter(
+                    id__lt=partition.id, partition_table=partition_table)
+                extended_size = extended_size - (
+                    previous_partitions.aggregate(Sum('size'))['size__sum'])
+                # Curtin adds 1MiB between each logical partition inside the
+                # extended partition. It incorrectly adds onto the size
+                # automatically so we have to extract that size from the
+                # overall size of the extended partition.
+                following_partitions = Partition.objects.filter(
+                    id__gte=partition.id, partition_table=partition_table)
+                logical_extra_space = following_partitions.count() * (1 << 20)
+                extended_size = extended_size - logical_extra_space
                 self.storage_config.append({
                     "id": "%s-part4" % block_device.get_name(),
                     "type": "partition",
                     "number": 4,
                     "device": block_device.get_name(),
                     "flag": "extended",
+                    "size": "%sB" % extended_size,
                 })
                 partition_operation["flag"] = "logical"
+                partition_operation["size"] = "%sB" % (
+                    partition.size - (1 << 20))
             elif partition_number > 5:
+                # Curtin adds 1MiB between each logical partition. We subtract
+                # the 1MiB from the size of the partition so all the partitions
+                # fit within the extended partition.
                 partition_operation["flag"] = "logical"
+                partition_operation["size"] = "%sB" % (
+                    partition.size - (1 << 20))
         self.storage_config.append(partition_operation)
 
     def _generate_format_operations(self):

=== modified file 'src/maasserver/tests/test_preseed_storage.py'
--- src/maasserver/tests/test_preseed_storage.py	2016-03-28 13:54:47 +0000
+++ src/maasserver/tests/test_preseed_storage.py	2016-07-03 15:21:41 +0000
@@ -256,12 +256,13 @@
             number: 4
             device: sda
             flag: extended
+            size: 4287627264B
           - id: sda-part5
             name: sda-part5
             type: partition
             number: 5
             uuid: 1b59e74f-6189-41a1-ba8e-fbf38df19820
-            size: 2147483648B
+            size: 2146435072B
             device: sda
             wipe: superblock
             flag: logical
@@ -270,7 +271,7 @@
             type: partition
             number: 6
             uuid: 8c365c80-900b-40a1-a8c7-1e445878d19a
-            size: 2139095040B
+            size: 2138046464B
             device: sda
             wipe: superblock
             flag: logical