this largely sorts out contention when using poudriere
```
commit 5f038de049cb35681379bf714a7eb5fea93a17a7 (HEAD -> nullfs-smr4)
Author: Mateusz Guzik <mjg@FreeBSD.org>
Date: Tue Sep 30 15:16:30 2025 +0000
nullfs: smr-protected hash lookup
Tested by: pho (previous version)
```