I've been getting a panic consistently while doing a build
from Saturday:

  panic: VDIROP being freed... this can't happen
  syncing disks...

and it locks up. I built a DDB kernel and got this trace:

  panic
  lfs_vflush
  lfs_update
  lfs_vsync
  vinvalbuf
  lfs_truncate
  ufs_direnter2
  ufs_direnter
  ufs_makeinode
  ufs_create
  lfs_create
  union_create
  vn_open
  sys_open
  syscall

The panic occurs while building the domestic tree. The build is
done on a union file system: an FFS mounted below an LFS, which
lives on a CCD stripe across two drives.

					Gary D. Duzan