Hi,

the reason is that our "zfs" package uses

  ("util-linux" ,util-linux "lib")

and then does

               (substitute* "lib/libzfs/libzfs_mount.c"
                 (("/bin/mount") (string-append util-linux "/bin/mount"))
                 (("/bin/umount") (string-append util-linux "/bin/umount")))

.

That can't work.

zfs interna that will be patched by the Guix package are:

./lib/libzfs/libzfs_mount.c

do_mount(const char *src, const char *mntpt, char *opts)

        char *argv[9] = {
            "/bin/mount",
            "--no-canonicalize",
            "-t", MNTTYPE_ZFS,
            "-o", opts,
            (char *)src,
            (char *)mntpt,
            (char *)NULL };

Easy fix would be to change our package to have both

  ("util-linux:lib" ,util-linux "lib")

and

  ("util-linux" ,util-linux)

.