DF-3015 run environment (QEMU/KVM guest)
=========================================
DragonFly dfbsd 6.5-DEVELOPMENT #0: Thu Jul  2 06:02:54 UTC 2026
  root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC  x86_64
kern.ident: X86_64_GENERIC (INVARIANTS enabled)
cc 8.3 [DragonFly] Release/2019-02-22
vfs.usermount: 0
hw.ncpu: 6
root fs: hammer2; test fs: UFS1 on vn0 (crafted image, 128MB,
         newfs defaults, mounted plain ufs - no softdep, no async)

Struct geometry (compiled against guest /usr/src headers):
  sizeof(struct inode) = 304  (kmalloc -> 320-byte slab chunk class,
                               zoneindex() rounds to 32-byte multiples)
  i_din @ 176, i_shortlink == di_db @ i_din+40  (di_db+di_ib span
  = UFS1_MAXSYMLINKLEN 60 bytes; dinode.h:114)
  neighbour chunk field f sits at overflow-payload index 104+f
  superblock: fs_maxsymlinklen at byte 8192+1320 = 9512 (int32 LE)