From dda140e0543254c4085db4ff1dacb2aa46303ae8 Mon Sep 17 00:00:00 2001
From: Janpieter Sollie <janpieter.sollie@kabelmail.de>
Date: Sat, 18 Nov 2023 14:37:51 +0100
Subject: [PATCH] ktest: use overlays to store arch-specific bcachefs-tools
 build

when running tests, eg test1 on arch 1, and then on arch 2,
the whole bcachefs-tools package needs to be rebuilt:
all binaries of arch 1 need to be erased, and recompiled for arch 2
when going back to arch 1, it happens again

This patch fixes the issue by applying a arch-specific overlay,
so bcachefs-tools doesn't need a full rebuild every time.
The overlay is mounted via fuse-overlay.
If this isn't available, it will fall back to rsync,
causing a larger waste of disk space,
and not-applied-immediately git commits.

Signed-of-by: jpsollie <janpieter.sollie@edpnet.be>
---
 lib/common.sh                        |  2 ++
 tests/bcachefs/bcachefs-test-libs.sh | 22 +++++++++++++++++++---
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/lib/common.sh b/lib/common.sh
index 0015c6fa..68982700 100644
--- a/lib/common.sh
+++ b/lib/common.sh
@@ -19,6 +19,8 @@ ktest_exit()
     fi
 
     [[ -n $ktest_tmp ]] && rm -rf "$ktest_tmp"
+    #umount overlayfs of bcachefs-tools if needed
+    [[ -n $ktest_tmp && $(grep bcachefs-tools-$ktest_arch /proc/mounts) ]] && umount $(grep bcachefs-tools-$ktest_arch /proc/mounts | cut -d' ' -f 2)
     true
 }
 
diff --git a/tests/bcachefs/bcachefs-test-libs.sh b/tests/bcachefs/bcachefs-test-libs.sh
index 90c36b6f..f6461b5f 100644
--- a/tests/bcachefs/bcachefs-test-libs.sh
+++ b/tests/bcachefs/bcachefs-test-libs.sh
@@ -7,16 +7,32 @@
 . $(dirname $(readlink -e "${BASH_SOURCE[0]}"))/../test-libs.sh
 bch_loc=$(dirname $(readlink -e "${BASH_SOURCE[0]}"))/bcachefs-tools
 
-require-git http://evilpiepirate.org/git/bcachefs-tools.git
-if [[ ! -f "${bch_loc}/.last_arch_for_compile" || "$(cat ${bch_loc}/.last_arch_for_compile)" != $ktest_arch ]]; then
+declare -A ov_dirs=(["tmp"]="${bch_loc}/../.tmp-bcachefs-tools-overlay" \
+              ["diff"]="${bch_loc}/../.bcachefs-tools-overlay-${ktest_arch}" \
+              ["merge"]="${bch_loc}/../bcachefs-tools-${ktest_arch}")
+
+for dir_overlay in ${ov_dirs[@]}; do
+  if [[ ! -d ${dir_overlay} ]]; then mkdir -p ${dir_overlay}; fi
+done
+
+if [[ $(which fuse-overlayfs) && ! $(grep bcachefs-tools-$ktest_arch /proc/mounts) ]]; then
+	fuse-overlayfs -o lowerdir=${bch_loc},upperdir=${ov_dirs["diff"]},workdir=${ov_dirs["tmp"]} ${ov_dirs["merge"]}
+elif [[ ! $(grep bcachefs-tools-$ktest_arch /proc/mounts) ]]; then
+	rsync -av ${bch_loc}/ ${ov_dirs["merge"]}/
+fi
+
+bch_loc=$(dirname $(readlink -e "${BASH_SOURCE[0]}"))/bcachefs-tools-${ktest_arch}
+
+if [[ ! -f "${bch_loc}/.last_arch_for_compile" || "$(cat ${bch_loc}/.last_arch_for_compile)" != ${ktest_arch} ]]; then
 	make -C ${bch_loc} clean >/dev/null 2>&1;
 	rm -rf "${bch_loc}/rust-src/target/*";
 	find ${bch_loc} -name "*.o" -exec rm {} \;
 	find ${bch_loc} -name "*.a" -exec rm {} \;
 	echo $ktest_arch > ${bch_loc}/.last_arch_for_compile
 fi
-require-make bcachefs-tools
 
+require-git http://evilpiepirate.org/git/bcachefs-tools.git
+require-make bcachefs-tools-${ktest_arch}
 require-kernel-config BCACHEFS_FS
 
 if [[ ! -v NO_BCACHEFS_DEBUG ]]; then