diff --git a/block/nbd-client.c b/block/nbd-client.c
index 1abfc6a..693110d 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -348,6 +348,7 @@ int nbd_client_session_init(NbdClientSession *client,
     int ret;

     /* NBD handshake */
+    qemu_set_block(sock);
     ret = nbd_receive_negotiate(sock, client->export_name,
                                 &client->nbdflags, &client->size,
                                 &client->blocksize);
diff --git a/qemu-nbd.c b/qemu-nbd.c
index c26c98e..008fbf0 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -224,6 +224,7 @@ static void *nbd_client_thread(void *arg)
         goto out;
     }

+    qemu_set_block(sock);
     ret = nbd_receive_negotiate(sock, NULL, &nbdflags,
                                 &size, &blocksize);
     if (ret < 0) {
diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c
index 6b97dc1..81f2660 100644
--- a/util/qemu-sockets.c
+++ b/util/qemu-sockets.c
@@ -747,6 +747,8 @@ int unix_connect_opts(QemuOpts *opts, Error **errp,
         }
     } while (rc == -EINTR);

+    qemu_set_nonblock(sock);
+
     if (connect_state != NULL && QEMU_SOCKET_RC_INPROGRESS(rc)) {
         connect_state->fd = sock;
         qemu_set_fd_handler2(sock, NULL, NULL, wait_for_connect,