Problems unmounting/fssyncking extern UFS filesystem

[O. Hartmann]

A while ago since now I receive kernel messages like this in FreeBSD
6.2-PRE/AMD64:

fsync: giving up on dirty
0xffffff000362c7c0: tag devfs, type VCHR
    usecount 1, writecount 0, refcount 325 mountedhere 0xffffff00504d8400
    flags ()
    v_object 0xffffff00013c80e0 ref 0 pages 1286
     lock type devfs: EXCL (count 1) by thread 0xffffff0050287260 (pid
14109)
        dev ufs/BACKUP

Filesystem is an external USB attached SATA HD, ohci() driven (due to
ehci() is not working stable and properly on FreeBSD 6.2).

Filesystem is mounted via amd() and there via the'script' option in
amd() due to problems of the amd() mounting process recognizing UFS
filesystems. After 30 seconds of inactivity the filesystems gets
dismounted. This worked quite well in the past, but now I see this
kernel error messages.

Before doing a PR, I would like to serious ask whether this is an issue
or not.

Regards,
Oliver