mount problems: file name too long with a 79 character name?

Hi,

---snip---
{71} <FreeBSD 5.1-CURRENT> [M87:~netchild/FreeBSD/SystemOnCD]
(62) root_at_ttyp0 # realpath work/SystemOnCD-1/usr/ports/distfiles |wc -c
      79

{0} <FreeBSD 5.1-CURRENT> [M87:~netchild/FreeBSD/SystemOnCD]
(63) root_at_ttyp0 # realpath /space/distfiles |wc -c
      17

{0} <FreeBSD 5.1-CURRENT> [M87:~netchild/FreeBSD/SystemOnCD]
(64) root_at_ttyp0 # mount -t unionfs -o -b /space/distfiles work/SystemOnCD-1/usr/ports/distfiles
unionfs: /space/distfiles: File name too long

{71} <FreeBSD 5.1-CURRENT> [M87:~netchild/FreeBSD/SystemOnCD]
(65) root_at_ttyp0 # mount -t unionfs -o -b /space/distfiles /mnt
---snip---

The same happens with nullfs, but not with ntfs. I can't find a
documented limitation in the man pages (expect ENAMETOOLONG in mount(2),
but the name is shorter than 255 characters). I also can't find
ENAMETOOLONG in /sys/fs/unionfs/* (as mount_unionfs returns EX_OSERR, so
it isn't the mount_unionfs utility which rejects the mount).

This is with a pre-statfs-changes current. Does this problem still
exists in a recent current? If yes: where does this ENAMETOOLONG come
from?

Bye,
Alexander.

P.S.: I don't complain about the wrong path printed with the error,
looking at the source makes it obvious why this happens and it's easy to
fix this without help.
-- 
                   It's not a bug, it's tradition!

http://www.Leidinger.net                       Alexander _at_ Leidinger.net
  GPG fingerprint = C518 BC70 E67F 143F BE91  3365 79E2 9C60 B006 3FE7