A suspicious warning in sys/boot/zfs/zfsimpl.c

When I built the world as of r237813, clang reported a warning which
caught my attention.

===> sys/boot/zfs (all)
clang  -O2 -pipe -march=pentium4 -DBOOTPROG=\"zfsloader\" -I/usr/src/sys/boot/zfs/../common -I/usr/src/sys/boot/zfs/../.. -I. -I/usr/src/sys/boot/zfs/../../../lib/libstand -I/usr/src/sys/boot/zfs/../../cddl/boot/zfs -ffreestanding -mpreferred-stack-boundary=2 -mno-mmx -mno-3dnow -mno-sse -mno-sse2 -mno-sse3 -msoft-float -Wformat -Wall -DNDEBUG -std=gnu99 -Qunused-arguments  -c /usr/src/sys/boot/zfs/zfs.c -o zfs.o
In file included from /usr/src/sys/boot/zfs/zfs.c:48:
/usr/src/sys/boot/zfs/zfsimpl.c:2033:19: warning: array index 264 is past the end of the array (which contains 192 elements) [-Warray-bounds]
                                memcpy(path, &dn.dn_bonus[sizeof(znode_phys_t)],
                                              ^           ~~~~~~~~~~~~~~~~~~~~
/usr/src/sys/boot/zfs/../../cddl/boot/zfs/zfsimpl.h:788:2: note: array 'dn_bonus' declared here
        uint8_t dn_bonus[DN_MAX_BONUSLEN - sizeof (blkptr_t)];
        ^

I don't have a zfs-powered machine, so I'm not sure whether this
warning is false-positive or not.

-- 
-|-__   YAMAMOTO, Taku
 | __ <     <taku_at_tackymt.homeip.net>

      - A chicken is an egg's way of producing more eggs. -