From 9344e5f554690d5e379b5426daebadef7c87baf5 Mon Sep 17 00:00:00 2001 From: "Daniel P. Berrange" Date: Wed, 10 Feb 2016 18:41:09 +0000 Subject: nbd: always query export list in fixed new style protocol With the new style protocol, the NBD client will currenetly send NBD_OPT_EXPORT_NAME as the first (and indeed only) option it wants. The problem is that the NBD protocol spec does not allow for returning an error message with the NBD_OPT_EXPORT_NAME option. So if the server mandates use of TLS, the client will simply see an immediate connection close after issuing NBD_OPT_EXPORT_NAME which is not user friendly. To improve this situation, if we have the fixed new style protocol, we can sent NBD_OPT_LIST as the first option to query the list of server exports. We can check for our named export in this list and raise an error if it is not found, instead of going ahead and sending NBD_OPT_EXPORT_NAME with a name that we know will be rejected. This improves the error reporting both in the case that the server required TLS, and in the case that the client requested export name does not exist on the server. If the server does not support NBD_OPT_LIST, we just ignore that and carry on with NBD_OPT_EXPORT_NAME as before. Signed-off-by: Daniel P. Berrange Message-Id: <1455129674-17255-12-git-send-email-berrange@redhat.com> Signed-off-by: Paolo Bonzini --- nbd/server.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'nbd/server.c') diff --git a/nbd/server.c b/nbd/server.c index 074a1e6d7d..3d2fb1055f 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -294,6 +294,8 @@ static int nbd_negotiate_handle_export_name(NBDClient *client, uint32_t length) } name[length] = '\0'; + TRACE("Client requested export '%s'", name); + client->exp = nbd_export_find(name); if (!client->exp) { LOG("export not found"); -- cgit v1.2.3