ZFS panic space_map.c line 110

Hi,

I have a file server running ZFS on -CURRENT. Someone has tried to
transfer a file with several gigabytes onto the system. The kernel
crashed with a panic and freezed up during spewing the panic. I've only
written down the most important messages:

solaris assert ss==NULL
zfs/space_map.c line 110

process: 160 spa_zio

I've heard that I can try to move the zpool cache away and import the
zpool with force once again. Will this help? I am asking because I
don't know if the panic is caused by a corrupt cache or corrupt
file system metadata. Maybe someone can explain it. (I had to switch the
server off very ungently and the underlying RAID is rebuilding, so I
can try it out later.)

Is this issue with inconsistent zpools well known? I've seen some posts
from 2007 and January 2009 that reported similar problems. Apparently
some people have lost their entire zpools multiple times already, as
far as I understood it.

One more piece of information I can give is that every hour the ZFS file
systems create snapshots. Maybe it triggered some inconsistency between
the writes to a file system and the snapshot, I cannot tell, because I
don't understand the condition.

--
Martin