wic/partionedfs: Avoid reserving space for non-existing ext. partition

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@mender.io>
Signed-off-by: Ross Burton <ross.burton@intel.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/scripts/lib/wic/plugins/imager/direct.py b/scripts/lib/wic/plugins/imager/direct.py
index 235eb24f59..7d38ab34fb 100644
--- a/scripts/lib/wic/plugins/imager/direct.py
+++ b/scripts/lib/wic/plugins/imager/direct.py
@@ -344,6 +344,10 @@ class PartitionedImage():
 
         logger.debug("Assigning %s partitions to disks", self.ptable_format)
 
+        # 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]
@@ -369,7 +373,7 @@ class PartitionedImage():
                 # Skip one sector required for the partitioning scheme overhead
                 self.offset += overhead
 
-            if self.realpart > 3:
+            if self.realpart > 3 and num_real_partitions > 4:
                 # Reserve a sector for EBR for every logical partition
                 # before alignment is performed.
                 if self.ptable_format == "msdos":
@@ -408,7 +412,7 @@ class PartitionedImage():
 
             if self.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 self.realpart > 3:
                         part.type = 'logical'
                         part.num = self.realpart + 1