[Bug 50557] New: USVFS (Mod Organizer 2) no longer working

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=50557

Bug ID: 50557
           Summary: USVFS (Mod Organizer 2) no longer working
           Product: Wine
           Version: 6.0
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: kernel32
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

USVFS is a component of Mod Organizer 2. It uses an OverlayFS-style method to
overlay mods on to (primarily Bethesda) games at runtime.

The patch in #47832 (upstreamed in 4.21) fixed this until at *least* 5.13 when
dlls/kernel32/file.c was largely migrated to dlls/kernelbase/file.c. In every
Wine version after 5.0 USFVS fails to run.

My attached logs are from USVFS's own debug log. The log suffixed wine-5.0
shows the functionality working as expected (if you search it for 'freeside'
you will find a mod correctly overlayed). The log suffixed wine-6.0 for
comparison shows the function not working.

----

I attempted to replace the applicable section in dlls/kernelbase/file.c to
replicate the changes made to kernel32 in 4.21 but had no success, however I
believe the problem is here somewhere.