Cannot rm files when ZFS is full

[grarpamp]

One week old build...

# df -i .
Filesystem   1K-blocks      Used Avail Capacity iused ifree %iused  Mounted on
ram01/mnt1 239465344 239465344     0   100%   13163     0  100%   /mnt1
# ls -aliT zero
20797 -rw-r--r--  1 user user  43515904 Jul 28 23:20:57 2009 zero
# rm -f zero
rm: zero: No space left on device
# :> zero
cannot create zero: File exists
# cp /dev/null zero
overwrite zero? (y/n [n]) y
# ls -aliT zero
20797 -rw-rw-rw-  1 root  wheel  0 Jul 28 23:25:17 2009 zero
# rm -f zero
[gone]