ci: share Linux restore artifacts before builds [CI]

ci/buildah-env.sh

@@ -22,6 +22,11 @@ moshiro_setup_buildah() {
   # The outer Podman container provides the user namespace and capabilities;
   # RUN does not need a second OCI runtime or nested cgroup management.
   export BUILDAH_ISOLATION="${BUILDAH_ISOLATION:-chroot}"
+  local info_fd
+  exec {info_fd}> "$store_home/.info.lock"
+  flock -w 900 "$info_fd" || { echo "could not lock Buildah info for $store_home" >&2; return 1; }
   buildah info >/dev/null
+  flock -u "$info_fd"
+  exec {info_fd}>&-
   echo "Buildah store: $store_home/.local/share/containers/storage ($BUILDAH_ISOLATION)"
 }