From c1100fa461c35310e7b76097cccc3f2b40f8c76b Mon Sep 17 00:00:00 2001
From: Ricardo Pardini <ricardo@pardini.net>
Date: Wed, 18 Jan 2023 17:24:19 +0100
Subject: [PATCH] armbian-next: still fighting `tee` leaking under duress,
 turns out I _hadn't_ really won

- last resort, use lazy umount.
- include `lsof` in hostdeps, useful to debug these situations
---
 lib/functions/host/prepare-host.sh |  2 +-
 lib/functions/host/tmpfs-utils.sh  | 17 +++++++++++++++--
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/lib/functions/host/prepare-host.sh b/lib/functions/host/prepare-host.sh
index 11494f67f..2de4dcb99 100644
--- a/lib/functions/host/prepare-host.sh
+++ b/lib/functions/host/prepare-host.sh
@@ -245,7 +245,7 @@ function adaptative_prepare_host_dependencies() {
 		kmod        # this causes initramfs rebuild, but is usually pre-installed, so no harm done unless it's an upgrade
 		libbison-dev libelf-dev libfdt-dev libfile-fcntllock-perl libmpc-dev libfl-dev liblz4-tool
 		libncurses-dev libssl-dev libusb-1.0-0-dev
-		linux-base locales
+		linux-base locales lsof
 		ncurses-base ncurses-term # for `make menuconfig`
 		ntpdate
 		patchutils pkg-config pv
diff --git a/lib/functions/host/tmpfs-utils.sh b/lib/functions/host/tmpfs-utils.sh
index f09b8e69d..e317260fb 100644
--- a/lib/functions/host/tmpfs-utils.sh
+++ b/lib/functions/host/tmpfs-utils.sh
@@ -71,11 +71,24 @@ function cleanup_tmpfs_for() {
 	if [[ "${umount_tmpfs}" == "umount_tmpfs" ]]; then
 		display_alert "cleanup_tmpfs_for: umount tmpfs" "${tmpfs_name}" "cleanup"
 		cd "${SRC}" || echo "cleanup_tmpfs_for: cd failed to ${SRC}" >&2 # avoid cwd in use error
-		umount "${tmpfs_path}" || {
-			display_alert "cleanup_tmpfs_for: umount failed" "${tmpfs_name} tmpfs umount failed" "err"
+		sync                                                             # let disk coalesce
+		umount "${tmpfs_path}" &> /dev/null || {
+			display_alert "cleanup_tmpfs_for: umount failed" "${tmpfs_name} tmpfs umount failed, will try lazy" "cleanup"
+			# Do a lazy umount... last-resort...
+			sync
+			umount -l "${tmpfs_path}" &> /dev/null || display_alert "cleanup_tmpfs_for: lazy umount failed" "${tmpfs_name} tmpfs lazy umount also failed" "cleanup"
+			sync
+		}
+
+		# Check if the tmpfs is still mounted after all that trying, log error, show debug, and give up with error
+		mountpoint -q "${tmpfs_path}" && {
+			display_alert "cleanup_tmpfs_for: umount failed" "${tmpfs_name} tmpfs still mounted after retries/lazy umount" "err"
 			# Show last-resort what's in there / what's using it to stderr
 			ls -la "${tmpfs_path}" >&2 || echo "cleanup_tmpfs_for: ls failed" >&2
 			lsof "${tmpfs_path}" >&2 || echo "cleanup_tmpfs_for: lsof dir failed" >&2
+			return 1 # sorry, we tried.
+		} || {
+			display_alert "cleanup_tmpfs_for: umount success" "${tmpfs_name}" "cleanup"
 		}
 	else
 		display_alert "cleanup_tmpfs_for: not umounting tmpfs" "${tmpfs_name}" "cleanup"