"About a week ago I released mdadm-3.1 I have now 'withdrawn' it meaning that it doesn't appear on the kernel.org mirrors any more, and I ask people not to use it. The reason is that it is not as reliable at managing a raid[56] reshape as I thought and it can corrupt data too easily. ..." http://marc.info/?l=linux-raid&m=125748985908870&w=2
Marked as -* now, ebuild kept in the tree so people see the message on it.