[PATCH 1/3] scripts/make-erofs.sh: Avoid unneeded calls to awk and chmod

Demi Marie Obenour
2025-09-19T23:28:17Z

These calls were made to work around permission problems, but it is much
cleaner to solve these problems by making every directory in the new
filesystem image writable so that cp can write to it.

Signed-off-by: Demi Marie Obenour <demiobenour@gmail.com>
---
Hyperfine confirms that this does improve performance, though there are
outliers.
---
scripts/make-erofs.sh | 22 +++++++++++-----------
1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/scripts/make-erofs.sh b/scripts/make-erofs.sh
index b47048ad747bd7dfcc28e0f1dfd75ec090fa7e09..82d37573ad0454e79becfddd05f93585df7b671c 100755
--- a/scripts/make-erofs.sh
+++ b/scripts/make-erofs.sh
@@ -30,18 +30,18 @@ while read -r arg1; do
fi
echo

- parent="$(dirname "$arg2")"
- awk -v parent="$parent" -v root="$root" 'BEGIN {
- n = split(parent, components, "/")
- for (i = 1; i <= n; i++) {
- printf "%s/", root
- for (j = 1; j <= i; j++)
- printf "%s/", components[j]
- print
- }
- }' | xargs -rd '\n' chmod +w -- 2>/dev/null || :
- mkdir -p -- "$root/$parent"
+ if [ "$arg2" = / ]; then
+ cp -RT -- "$arg1" "$root"
+ # Nix store paths are read-only, so fix up permissions
+ # so that subsequent copies can write to directories
+ # created by the above copy. This means giving all
+ # directories 0755 permissions.
+ find "$root" -type d -exec chmod 0755 -- '{}' +
+ continue
+ fi

+ parent=$(dirname "$arg2")
+ mkdir -p -- "$root/$parent"
cp -RT -- "$arg1" "$root/$arg2"
done

--
2.51.0