Linux kernel NBD driver support for structured replies?

[Josh Triplett <josh@joshtriplett.org>]

I'm currently using the NBD client driver in the Linux kernel. At some
point, I'd be interested in adding support for structured replies,
specifically so that an NBD server can efficiently handle ranges of
zeroes (e.g.  "for the 4k block you asked for, here are 200 bytes of
data, and the rest if zero").

Does that seem reasonable to add to the kernel driver? I wanted to check
before considering development of a patch.

- Josh Triplett