# DF-3058 verification

Kernel: 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

Not executable on this rig: dirfs is dead code in the current tree - sys/vfs/dirfs/ has no Makefile, is not referenced by sys/conf/files, is in no kernel config, and kldload dirfs fails (module not built). mount_dirfs additionally refuses to run on non-vkernel platforms (sbin/mount_dirfs/mount_dirfs.c:105). The contract breach is code-certain from source: dirfs_vnops.c:588-595 computes error = fsync(dnp->dn_fd) twice (second call on failure stores -1, not errno) and then returns 0 unconditionally.

## Kernel references
- sys/vfs/dirfs/dirfs_vnops.c:588
- sys/vfs/dirfs/dirfs_vnops.c:595

## Fix
See fix.diff.

## Fix status (batch validation)
Applied with the 36 sibling fix.diffs of this batch in findings/poc/_batch41/all_fixes.patch; single in-guest `make -j6 nativekernel KERNCONF=X86_64_GENERIC` completed RC=0 with zero errors under -Werror (full log: findings/poc/_batch41/fix_build8.log). Behavior A/B intentionally skipped for this Info-tier item.