This looks a bit similar to LU-3903.

I can no longer build lustre against the latest upstream zfs source pulled from the master branch of github.com/behlendorf/zfs.git. The internal API dsl_sync_task_do_nowait() used in osd-zfs code no longer exists.

This is not currently a problem in our build and test framework where builds are done against an earlier, fixed, and frozen version of zfs source. It will become a problem the next time we sync up to the latest upstream zfs version.