[PATCH 2/2] wic/engine: use up all free space when expanding partitions

[Anuj Mittal <anuj.mittal@intel.com>]

Currently we just divide up the free space by the number of partitions
that need to be re-sized. This leads to problems when a user has
explicitly specified a subset of partitions (but not all) that need
to re-sized along with the sizes. As an example, for an image with 3
partitions, if we use:

wic write image.wic /dev/sdb --expand 1:10G

This would lead to paritions 2 and 3 each being re-sized to one thirds
of the free space instead of half.

Change the behavior to use up all the free space.

Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>
---
 scripts/lib/wic/engine.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/scripts/lib/wic/engine.py b/scripts/lib/wic/engine.py
index fe036f60e9..f0c5ff0aaf 100644
--- a/scripts/lib/wic/engine.py
+++ b/scripts/lib/wic/engine.py
@@ -416,6 +416,7 @@ class Disk:
 
             # calculate expanded partitions sizes
             sizes = {}
+            num_auto_resize = 0
             for num, part in enumerate(parts['partitiontable']['partitions'], 1):
                 if num in expand:
                     if expand[num] != 0: # don't resize partition if size is set to 0
@@ -425,10 +426,11 @@ class Disk:
                         sizes[num] = sectors
                 elif part['type'] != 'f':
                     sizes[num] = -1
+                    num_auto_resize += 1
 
             for num, part in enumerate(parts['partitiontable']['partitions'], 1):
                 if sizes.get(num) == -1:
-                    part['size'] += free // len(sizes)
+                    part['size'] += free // num_auto_resize
 
             # write resized partition table to the target
             write_ptable(parts, target)
-- 
2.17.1