nbd: Improve debug traces on little-endian

Print debug tracing messages while data is still in native
ordering, rather than after we've potentially swapped it into
network order for transmission.  Also, it's nice if the server
mentions what it is replying, to correlate it to with what the
client says it is receiving.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1459913704-19949-4-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

2 files changed, 7 insertions, 6 deletions

diff --git a/nbd/client.c b/nbd/client.c
index d9b7a9b..1593cd6 100644
--- a/nbd/client.c
+++ b/nbd/client.c
@@ -628,16 +628,16 @@ ssize_t nbd_send_request(QIOChannel *ioc, struct nbd_request *request)
     uint8_t buf[NBD_REQUEST_SIZE];
     ssize_t ret;
 
+    TRACE("Sending request to server: "
+          "{ .from = %" PRIu64", .len = %u, .handle = %" PRIu64", .type=%i}",
+          request->from, request->len, request->handle, request->type);
+
     cpu_to_be32w((uint32_t*)buf, NBD_REQUEST_MAGIC);
     cpu_to_be32w((uint32_t*)(buf + 4), request->type);
     cpu_to_be64w((uint64_t*)(buf + 8), request->handle);
     cpu_to_be64w((uint64_t*)(buf + 16), request->from);
     cpu_to_be32w((uint32_t*)(buf + 24), request->len);
 
-    TRACE("Sending request to server: "
-          "{ .from = %" PRIu64", .len = %u, .handle = %" PRIu64", .type=%i}",
-          request->from, request->len, request->handle, request->type);
-
     ret = write_sync(ioc, buf, sizeof(buf));
     if (ret < 0) {
         return ret;
diff --git a/nbd/server.c b/nbd/server.c
index 98e3957..6d9c15a 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -656,6 +656,9 @@ static ssize_t nbd_send_reply(QIOChannel *ioc, struct nbd_reply *reply)
 
     reply->error = system_errno_to_nbd_errno(reply->error);
 
+    TRACE("Sending response to client: { .error = %d, handle = %" PRIu64 " }",
+          reply->error, reply->handle);
+
     /* Reply
        [ 0 ..  3]    magic   (NBD_REPLY_MAGIC)
        [ 4 ..  7]    error   (0 == no error)
@@ -665,8 +668,6 @@ static ssize_t nbd_send_reply(QIOChannel *ioc, struct nbd_reply *reply)
     stl_be_p(buf + 4, reply->error);
     stq_be_p(buf + 8, reply->handle);
 
-    TRACE("Sending response to client");
-
     ret = write_sync(ioc, buf, sizeof(buf));
     if (ret < 0) {
         return ret;