On 14/03/2015 16:38, Matthew D. Fuller wrote: >> I couldn't really say which... > My conclusion is that this is a zvol bug. With the patch in > <https://lists.freebsd.org/pipermail/freebsd-fs/2015-March/020960.html>, > it all seems to work fine. > Correct, committed: https://svnweb.freebsd.org/changeset/base/279996