cannot mount small FFS filesystem?

[Hubert Feyrer <hubert%feyrer.de@localhost>]

I have a storage device that only has 47k space. I'd like to put FFS (v1 
or v2) with journaling on it. newfs(8) works fine, but mount(8) complains:

        mount_ffs: /dev/vnd0a on /mnt: incorrect super block

The commands I give for testing:

# dd if=/dev/zero of=img bs=512 count=94
# vnconfig vnd0 img
# newfs -m 0 -O 1 /dev/rvnd0a
# mount -o log /dev/vnd0a /mnt

Full log with output is appended below.

I've tried adding -m0 and -O1 to newfs, but couldn't mount it, without 
without logging.
Is there anything obvious I'm missing?

Thanks a lot in advance!


 - Hubert


Full log with output:

# dd if=/dev/zero of=img bs=512 count=94
94+0 records in
94+0 records out
48128 bytes transferred in 0.004 secs (12032000 bytes/sec)
# vnconfig vnd0 img
# newfs -m 0 -O 1 /dev/rvnd0a
newfs: Warning: changing optimization to space because minfree is less 
than 5%
/dev/rvnd0a: 0.0MB (94 sectors) block size 4096, fragment size 512
        using 1 cylinder groups of 0.05MB, 12 blks, 32 inodes.
super-block backups (for fsck_ffs -b #) at:
32,
# mount -o log /dev/vnd0a /mnt
mount_ffs: /dev/vnd0a on /mnt: incorrect super block
#

# uname -rms
NetBSD 5.1_RC2 i386