wic/utils/partitionedfs.py: assemble .wic images as sparse files

The individual partitions created by wic are sparse but without
this change the assembled image is written as one (potentially
very) large file.

Preserve sparseness in the assembled image by passing the sparse
conversion symbol.

[YOCTO #9099]

(From OE-Core rev: 5fd592fbae2e046bcb8c3a6c3ef4993fe0400676)

Signed-off-by: Joshua Lock <joshua.lock@collabora.co.uk>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/scripts/lib/wic/utils/partitionedfs.py b/scripts/lib/wic/utils/partitionedfs.py
index 5a103bbc7e..3e2b420875 100644
--- a/scripts/lib/wic/utils/partitionedfs.py
+++ b/scripts/lib/wic/utils/partitionedfs.py
@@ -340,7 +340,7 @@ class Image(object):
             source = part['source_file']
             if source:
                 # install source_file contents into a partition
-                cmd = "dd if=%s of=%s bs=%d seek=%d count=%d conv=notrunc" % \
+                cmd = "dd if=%s of=%s bs=%d seek=%d count=%d conv=notrunc,sparse" % \
                       (source, image_file, self.sector_size,
                        part['start'], part['size'])
                 exec_cmd(cmd)