I just had a problem with softdep, after filling a filesystem the
contents of about 2Gb of recently-written files disappeared, leaving
me with 0-length files.  Shortly thereafter, while doing further
testing, I had a panic.

Investigations continue, in the meantime it might be a good idea to
avoid softdep, certainly if you're likely to fill filesystems, for
just a little while longer.

tunefs -n disable ... on the unmounted raw device will turn it off
again.

--
Dan.