Filtering/converting in user-space has long been part of zap: used to
be able to migrate between both minor and major versions of the kernel
(always upwards, of course).
In fact, I already proposed it as part of the original thread that led
eventually to the patch in question:
https://lists.linux-foundation.org/pipermail/containers/2008-February/009849.html
The need to be able to specify a desired ID (from user-space and/or from
in-kernel) remains.
Oren.
--