nbd: Trace client command being sent

Make the client trace slightly more legible by including the name
of the command being sent.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-Id: <20170717192635.17880-2-eblake@redhat.com>

nbd/client.c

@@ -901,7 +901,8 @@ ssize_t nbd_send_request(QIOChannel *ioc, NBDRequest *request)
     uint8_t buf[NBD_REQUEST_SIZE];
 
     trace_nbd_send_request(request->from, request->len, request->handle,
-                           request->flags, request->type);
+                           request->flags, request->type,
+                           nbd_cmd_lookup(request->type));
 
     stl_be_p(buf, NBD_REQUEST_MAGIC);
     stw_be_p(buf + 4, request->flags);

nbd/trace-events

@@ -28,7 +28,7 @@ nbd_client_loop(void) "Doing NBD loop"
 nbd_client_loop_ret(int ret, const char *error) "NBD loop returned %d: %s"
 nbd_client_clear_queue(void) "Clearing NBD queue"
 nbd_client_clear_socket(void) "Clearing NBD socket"
-nbd_send_request(uint64_t from, uint32_t len, uint64_t handle, uint16_t flags, uint16_t type) "Sending request to server: { .from = %" PRIu64", .len = %" PRIu32 ", .handle = %" PRIu64 ", .flags = %" PRIx16 ", .type = %" PRIu16 " }"
+nbd_send_request(uint64_t from, uint32_t len, uint64_t handle, uint16_t flags, uint16_t type, const char *name) "Sending request to server: { .from = %" PRIu64", .len = %" PRIu32 ", .handle = %" PRIu64 ", .flags = %" PRIx16 ", .type = %" PRIu16 " (%s) }"
 nbd_receive_reply(uint32_t magic, int32_t error, uint64_t handle) "Got reply: { magic = 0x%" PRIx32 ", .error = % " PRId32 ", handle = %" PRIu64" }"
 
 # nbd/server.c