From: Lennart Poettering <lennart@poettering.net>
Date: Fri, 8 Oct 2021 10:40:13 +0000 (+0200)
Subject: mkosi: when done, dig out all holes (unless we compress anyway)
X-Git-Tag: v11~34^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F830%2Fhead;p=thirdparty%2Fmkosi.git

mkosi: when done, dig out all holes (unless we compress anyway)

We likely have some NUL bytes in the image, let's explicitly seek them
out and punch holes into them.
---

diff --git a/mkosi/__init__.py b/mkosi/__init__.py
index fb30e7bef..9dec8eaa4 100644
--- a/mkosi/__init__.py
+++ b/mkosi/__init__.py
@@ -3942,11 +3942,16 @@ def extract_unified_kernel(
 def compress_output(
     args: CommandLineArguments, data: Optional[BinaryIO], suffix: Optional[str] = None
 ) -> Optional[BinaryIO]:
+
     if data is None:
         return None
     compress = should_compress_output(args)
 
     if not compress:
+        # If we shan't compress, then at least make the output file sparse
+        with complete_step(f"Digging holes into output file {data.name}…"):
+            run(["fallocate", "--dig-holes", data.name])
+
         return data
 
     with complete_step(f"Compressing output file {data.name}…"):