Comment 26 for bug 1804603

I didn't find any conflict or overlap applying the btrfs-util-unbreak-tmpfiles-subvol-creation on top of the other patches on the source package systemd_237-3ubuntu10.9.debian, although the codebase of src/basic/btrfs-util.c affected by the patch had different hunks regards to the file in systemd_239.
So to apply the patch conceived by Brian Murray on bionic
I only had to add the missing macro FLAGS_SET on macro.h and refreshed the patch
here's the missing part to make it compile on bionic

Index: systemd-237/src/basic/macro.h
===================================================================
--- systemd-237.orig/src/basic/macro.h
+++ systemd-237/src/basic/macro.h
@@ -351,6 +351,9 @@ static inline unsigned long ALIGN_POWER2
 #define SET_FLAG(v, flag, b) \
         (v) = (b) ? ((v) | (flag)) : ((v) & ~(flag))

+#define FLAGS_SET(v, flags) \
+ (((v) & (flags)) == (flags))
+
 #define CASE_F(X) case X:
 #define CASE_F_1(CASE, X) CASE_F(X)
 #define CASE_F_2(CASE, X, ...) CASE(X) CASE_F_1(CASE, __VA_ARGS__)

The error of tmp disappeared at the boot, and the security issues should be patched by the preceding CVE-2018-6954* patches.
Let me know if I should submit the patch. Anyway I'm not a good programmer so wait for hints of maintainers, Brian Murray or other guru.

Regards