I can reproduce this problem and the bug is already filed:
The root cause is that a ZFS clone must be unmounted to be renamed, which is a bug.
The workaround is easy enough, just unmount the BE before you rename it.
Thanks very much.
I have learned that the procedure of "be rename" including the following steps(it is not so correctly):
1. gather the mount infomation
3. proccessing rename
When I trace the "be rename" , I have found that, before the error occurring it tried to mount the renamed dataset(renametest) to the "/" which has already been mounted.
I can't access the webpage:
It seems that there is no such page or website(https://bug.oraclecorp.com).
Looking forward for your reply.