[slx-dmsetup] Fix braindead mktemp call by removing it

1 files changed, 5 insertions, 4 deletions

diff --git a/modules.d/slx-dmsetup/hooks/dmsetup-slx-device b/modules.d/slx-dmsetup/hooks/dmsetup-slx-device
index 0888e97c..4c41af4b 100755
--- a/modules.d/slx-dmsetup/hooks/dmsetup-slx-device
+++ b/modules.d/slx-dmsetup/hooks/dmsetup-slx-device
@@ -241,15 +241,16 @@ ramdisk_fallback() {
 		mkdir -p "$cow_tmpfs"
 	fi
 	if ! mount -t tmpfs cow-tmpfs -o size="$(( read_only_device_sz / 2 + 100 ))k" "$cow_tmpfs"; then
-		echo "$0: Failed to mount tmpfs in '$cow_tmpfs' of size '$(( read_only_device_sz / 2 + 100 ))KiB'."
+		echo "$0: Failed to mount tmpfs in '$cow_tmpfs' of size '$(( read_only_device_sz / 2 + 100 ))KiB', trying to use regular /run tmpfs."
 	fi
 
 	# create sparse file there
-	local file="$(mktemp -u -p "$cow_tmpfs" dnbd_cow.XXX)"
-	if ! dd if=/dev/null of="$file" seek="$(( read_only_device_sz ))" bs=512 2> /dev/null; then
+	local file="$cow_tmpfs/thinpool.meta"
+	if ! truncate -s "$(( read_only_device_sz * 512 ))" "$file" \
+			&& ! dd if=/dev/null of="$file" seek="$read_only_device_sz" bs=512 2> /dev/null; then
 		emergency_shell "Failed to allocate CoW file $file."
 	fi
-	declare -rg writable_device="$(losetup --show --find "$file")"
+	declare -rg writable_device="$( losetup --show --find "$file" )"
 	local cow_device_candidate="root"
 	while [ -b "/dev/mapper/$cow_device_candidate" ]; do
 		cow_device_candidate="root.$RANDOM"