Would be nice to have ZFS-specific samba4 plugins such as `vfs_shadow_copy_zfs` as found in: https://github.com/freenas/ports/blob/freenas/master/net/samba411 (as previously requested against samb410 in bug #244054)
As I stated before I don't mind adding this module to the codebase, I hope Andrew and iXsystems Inc. do not either. The biggest problem I see myself in is the need for the libzfs, which most of those modules use and requires an actual kernel source for the running kernel. FreeNAS has the luxury of pinning the kernel version and source for their releases, while the port has to fit multiple OS releases and kernel versions. So, as soon as someone would be able to help in creating working libzfs port I'd be glad to add corresponding modules.