diff --git a/block/nbd.c b/block/nbd.c
index 9db5eded89..83e6e9e442 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -528,6 +528,16 @@ static void nbd_refresh_filename(BlockDriverState *bs, QDict *options)
     bs->full_open_options = opts;
 }
 
+static char *nbd_dirname(BlockDriverState *bs, Error **errp)
+{
+    /* The generic bdrv_dirname() implementation is able to work out some
+     * directory name for NBD nodes, but that would be wrong. So far there is no
+     * specification for how "export paths" would work, so NBD does not have
+     * directory names. */
+    error_setg(errp, "Cannot generate a base directory for NBD nodes");
+    return NULL;
+}
+
 static BlockDriver bdrv_nbd = {
     .format_name                = "nbd",
     .protocol_name              = "nbd",
@@ -546,6 +556,7 @@ static BlockDriver bdrv_nbd = {
     .bdrv_attach_aio_context    = nbd_attach_aio_context,
     .bdrv_refresh_filename      = nbd_refresh_filename,
     .bdrv_co_block_status       = nbd_client_co_block_status,
+    .bdrv_dirname               = nbd_dirname,
 };
 
 static BlockDriver bdrv_nbd_tcp = {
@@ -566,6 +577,7 @@ static BlockDriver bdrv_nbd_tcp = {
     .bdrv_attach_aio_context    = nbd_attach_aio_context,
     .bdrv_refresh_filename      = nbd_refresh_filename,
     .bdrv_co_block_status       = nbd_client_co_block_status,
+    .bdrv_dirname               = nbd_dirname,
 };
 
 static BlockDriver bdrv_nbd_unix = {
@@ -586,6 +598,7 @@ static BlockDriver bdrv_nbd_unix = {
     .bdrv_attach_aio_context    = nbd_attach_aio_context,
     .bdrv_refresh_filename      = nbd_refresh_filename,
     .bdrv_co_block_status       = nbd_client_co_block_status,
+    .bdrv_dirname               = nbd_dirname,
 };
 
 static void bdrv_nbd_init(void)