RFC for NBD protocol extension: extended headers
In response to this mail, I will be cross-posting a series of patches
to multiple projects as a proof-of-concept implementation and request
for comments on a new NBD protocol extension, called
NBD_OPT_EXTENDED_HEADERS. With this in place, it will be possible for
clients to request 64-bit zero, trim, cache, and block status
operations when supported by the server.
Not yet complete: an implementation of this in nbdkit. I also plan to
tweak libnbd's 'nbdinfo --map' and 'nbdcopy' to take advantage of the
larger block status results. Also, with 64-bit commands, we may want
to also make it easier to let servers advertise an actual maximum size
they are willing to accept for the commands in question (for example,
a server may be happy with a full 64-bit block status, but still want
to limit non-fast zero and cache to a smaller limit to avoid denial of
service).
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
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