nbd: Simplify trace of client flags in negotiation

Simplify the tracing of client flags in the server, and return -EINVAL
instead of -EIO if we successfully read but don't like those flags.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20170707203049.534-5-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

nbd/server.c

@@ -396,21 +396,19 @@ static int nbd_negotiate_options(NBDClient *client, Error **errp)
         error_prepend(errp, "read failed: ");
         return -EIO;
     }
-    trace_nbd_negotiate_options_flags();
     be32_to_cpus(&flags);
+    trace_nbd_negotiate_options_flags(flags);
     if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) {
-        trace_nbd_negotiate_options_newstyle();
         fixedNewstyle = true;
         flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE;
     }
     if (flags & NBD_FLAG_C_NO_ZEROES) {
-        trace_nbd_negotiate_options_no_zeroes();
         client->no_zeroes = true;
         flags &= ~NBD_FLAG_C_NO_ZEROES;
     }
     if (flags != 0) {
         error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags);
-        return -EIO;
+        return -EINVAL;
     }
 
     while (1) {

nbd/trace-events

@@ -35,9 +35,7 @@ nbd_negotiate_handle_export_name(void) "Checking length"
 nbd_negotiate_handle_export_name_request(const char *name) "Client requested export '%s'"
 nbd_negotiate_handle_starttls(void) "Setting up TLS"
 nbd_negotiate_handle_starttls_handshake(void) "Starting TLS handshake"
-nbd_negotiate_options_flags(void) "Checking client flags"
-nbd_negotiate_options_newstyle(void) "Client supports fixed newstyle handshake"
-nbd_negotiate_options_no_zeroes(void) "Client supports no zeroes at handshake end"
+nbd_negotiate_options_flags(uint32_t flags) "Received client flags 0x%" PRIx32
 nbd_negotiate_options_check_magic(uint64_t magic) "Checking opts magic 0x%" PRIx64
 nbd_negotiate_options_check_option(uint32_t option, const char *name) "Checking option 0x%" PRIx32 " (%s)"
 nbd_negotiate_begin(void) "Beginning negotiation"