On 10/3/18 12:19 PM, Eric Blake wrote:
Oldstyle NBD negotiation cannot perform any of the extensions that
we have recently been relying on. While you can always pass -x ""
to get newstyle negotiation, these days, it is better to just default
to newstyle (with an empty export name) and fall back to oldstyle
only on an explicit request.
For comparison:
nbdkit 1.3 switched its default to newstyle (Jan 2018):
https://github.com/libguestfs/nbdkit/commit/b2a8aecc
https://github.com/libguestfs/nbdkit/commit/8158e773
nbd 3.10 dropped oldstyle long ago (Mar 2015):
https://github.com/NetworkBlockDevice/nbd/commit/36940193
Oh, I should also add:
qemu as client can manage either style since 2.6.0, commit 69b49502d8
+++ b/qemu-nbd.c
@@ -86,6 +86,7 @@ static void usage(const char *name)
" -v, --verbose display extra debugging information\n"
" -x, --export-name=NAME expose export by name\n"
" -D, --description=TEXT with -x, also export a human-readable
description\n"
+" -O, --oldstyle force oldstyle negotiation\n"
and maybe I should touch up the -x and -D wording, to at least mention
that -x defaults to "" without -O.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
