[PATCH] .gitignore: Keep track of archived files as they are added to a new git repo

[Like Xu <like.xu.linux@gmail.com>]

From: Like Xu <likexu@tencent.com>

With thousands of commits going into mainline each development cycle,
the metadata .git folder size is gradually expanding (1GB+), and for some
developers (most likely testers) who don't care about the lengthy git-log,
they just use git-archive to distribute a certain version of code (~210MB)
and rebuild git repository from anywhere for further code changes, e.g.

  $ git init && git add . -A

Then unfortunately, the file tracking metadata from the original git-repo
using "git add -f" will also be lost, to the point where part of source
files wrapped by git-archive may be accidentally cleaned up:

  $ git clean -nxdf
  Would remove Documentation/devicetree/bindings/.yamllint
  Would remove drivers/clk/.kunitconfig
  Would remove drivers/gpu/drm/tests/.kunitconfig
  Would remove drivers/hid/.kunitconfig
  Would remove fs/ext4/.kunitconfig
  Would remove fs/fat/.kunitconfig
  Would remove kernel/kcsan/.kunitconfig
  Would remove lib/kunit/.kunitconfig
  Would remove mm/kfence/.kunitconfig
  Would remove tools/testing/selftests/arm64/tags/
  Would remove tools/testing/selftests/kvm/.gitignore
  Would remove tools/testing/selftests/kvm/Makefile
  Would remove tools/testing/selftests/kvm/config
  Would remove tools/testing/selftests/kvm/settings

This asymmetry is very troubling to those users since finding out which
files to track with "git add -f" clearly requires priori knowledge on
various subsystems. The eradication of this little issue requires naturally
making git-init aware of all .gitignore restrictions at different file tree
hierarchies. Similar issues can be troubleshot with "git check-ignore -v"
for any mistakenly cleaned files.

Signed-off-by: Like Xu <likexu@tencent.com>
---
 .gitignore                               | 2 ++
 tools/testing/selftests/arm64/.gitignore | 2 ++
 tools/testing/selftests/kvm/.gitignore   | 4 ++++
 3 files changed, 8 insertions(+)
 create mode 100644 tools/testing/selftests/arm64/.gitignore

diff --git a/.gitignore b/.gitignore
index 20dce5c3b9e0..fa39e98caee3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -102,6 +102,8 @@ modules.order
 !.gitignore
 !.mailmap
 !.rustfmt.toml
+!.yamllint
+!.kunitconfig
 
 #
 # Generated include files
diff --git a/tools/testing/selftests/arm64/.gitignore b/tools/testing/selftests/arm64/.gitignore
new file mode 100644
index 000000000000..135d709d2d65
--- /dev/null
+++ b/tools/testing/selftests/arm64/.gitignore
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+!tags
diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index 6d9381d60172..96561c8e06e0 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore
@@ -5,3 +5,7 @@
 !*.h
 !*.S
 !*.sh
+!.gitignore
+!Makefile
+!settings
+!config
\ No newline at end of file
-- 
2.39.1