Received: from eggs.gnu.org ([2001:4830:134:3::10]:33260) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1g7koc-00008b-1W for qemu-devel@nongnu.org; Wed, 03 Oct 2018 13:20:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1g7koa-0001Vo-WB for qemu-devel@nongnu.org; Wed, 03 Oct 2018 13:20:02 -0400 From: Eric Blake Date: Wed, 3 Oct 2018 12:19:47 -0500 Message-Id: <20181003171947.588103-1-eblake@redhat.com> Subject: [Qemu-devel] [PATCH] nbd: Flip qemu-nbd to prefer newstyle; add -O for old behavior List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: vsementsov@virtuozzo.com, Paolo Bonzini , "open list:Network Block Dev..." 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 Signed-off-by: Eric Blake --- qemu-nbd.c | 27 +++++++++++++++++++-------- 1 file changed, 19 insertions(+), 8 deletions(-) diff --git a/qemu-nbd.c b/qemu-nbd.c index 51b9d38c727..8571a4f93d8 100644 --- a/qemu-nbd.c +++ 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" "\n" "Exposing part of the image:\n" " -o, --offset=OFFSET offset into the image\n" @@ -529,6 +530,7 @@ int main(int argc, char **argv) { "object", required_argument, NULL, QEMU_NBD_OPT_OBJECT }, { "export-name", required_argument, NULL, 'x' }, { "description", required_argument, NULL, 'D' }, + { "oldstyle", no_argument, NULL, 'O' }, { "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS }, { "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS }, { "trace", required_argument, NULL, 'T' }, @@ -551,6 +553,7 @@ int main(int argc, char **argv) QDict *options = NULL; const char *export_name = NULL; const char *export_description = NULL; + bool oldstyle = false; const char *tlscredsid = NULL; bool imageOpts = false; bool writethrough = true; @@ -723,6 +726,9 @@ int main(int argc, char **argv) case 'D': export_description = optarg; break; + case 'O': + oldstyle = true; + break; case 'v': verbose = 1; break; @@ -799,7 +805,16 @@ int main(int argc, char **argv) } } + if (!oldstyle && !export_name) { + /* Set the default NBD protocol export name, to favor new style. */ + export_name = ""; + } + if (tlscredsid) { + if (oldstyle) { + error_report("TLS is incompatible with oldstyle"); + exit(EXIT_FAILURE); + } if (sockpath) { error_report("TLS is only supported with IPv4/IPv6"); exit(EXIT_FAILURE); @@ -808,11 +823,6 @@ int main(int argc, char **argv) error_report("TLS is not supported with a host device"); exit(EXIT_FAILURE); } - if (!export_name) { - /* Set the default NBD protocol export name, since - * we *must* use new style protocol for TLS */ - export_name = ""; - } tlscreds = nbd_get_tls_creds(tlscredsid, &local_err); if (local_err) { error_report("Failed to get TLS creds %s", @@ -1013,13 +1023,14 @@ int main(int argc, char **argv) error_report_err(local_err); exit(EXIT_FAILURE); } + if (oldstyle && (export_name || export_description)) { + error_report("oldstyle negotiation cannot set export details"); + exit(EXIT_FAILURE); + } if (export_name) { nbd_export_set_name(exp, export_name); nbd_export_set_description(exp, export_description); newproto = true; - } else if (export_description) { - error_report("Export description requires an export name"); - exit(EXIT_FAILURE); } if (device) { -- 2.17.1