[OE-core] [PATCH] wic/partionedfs: Avoid reserving space for non-existing ext. partition

[Kristian Amlie]

We don't need the gap that the extended partition occupies if we
already know that we have less than five partitions. Saves up to one
full alignment of space.

Signed-off-by: Kristian Amlie <kristian.amlie at mender.io>
---
 scripts/lib/wic/utils/partitionedfs.py | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/scripts/lib/wic/utils/partitionedfs.py b/scripts/lib/wic/utils/partitionedfs.py
index 721d514..9db6d56 100644
--- a/scripts/lib/wic/utils/partitionedfs.py
+++ b/scripts/lib/wic/utils/partitionedfs.py
@@ -131,6 +131,10 @@ class Image():
 
         self._partitions_layed_out = True
 
+        # The number of primary and logical partitions. Extended partition and
+        # partitions not listed in the table are not included.
+        num_real_partitions = len([p for p in self.partitions if not p['no_table']])
+
         # Go through partitions in the order they are added in .ks file
         for num in range(len(self.partitions)):
             part = self.partitions[num]
@@ -162,7 +166,7 @@ class Image():
                 # Skip one sector required for the partitioning scheme overhead
                 disk['offset'] += overhead
 
-            if disk['realpart'] > 3:
+            if disk['realpart'] > 3 and num_real_partitions > 4:
                 # Reserve a sector for EBR for every logical partition
                 # before alignment is performed.
                 if ptable_format == "msdos":
@@ -202,7 +206,7 @@ class Image():
 
             if disk['ptable_format'] == "msdos":
                 # only count the partitions that are in partition table
-                if len([p for p in self.partitions if not p['no_table']]) > 4:
+                if num_real_partitions > 4:
                     if disk['realpart'] > 3:
                         part['type'] = 'logical'
                         part['num'] = disk['realpart'] + 1
-- 
2.7.4