block: auto-generated node-names

If a node-name is not specified, automatically generate the node-name.

Generated node-names will use the "block" sub-system identifier.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 12 insertions, 7 deletions

diff --git a/block.c b/block.c
index 6490040b43..09f2a754f1 100644
--- a/block.c
+++ b/block.c
@@ -763,12 +763,15 @@ static void bdrv_assign_node_name(BlockDriverState *bs,
                                   const char *node_name,
                                   Error **errp)
 {
-    if (!node_name) {
-        return;
-    }
+    char *gen_node_name = NULL;
 
-    /* Check for empty string or invalid characters */
-    if (!id_wellformed(node_name)) {
+    if (!node_name) {
+        node_name = gen_node_name = id_generate(ID_BLOCK);
+    } else if (!id_wellformed(node_name)) {
+        /*
+         * Check for empty string or invalid characters, but not if it is
+         * generated (generated names use characters not available to the user)
+         */
         error_setg(errp, "Invalid node name");
         return;
     }
@@ -777,18 +780,20 @@ static void bdrv_assign_node_name(BlockDriverState *bs,
     if (blk_by_name(node_name)) {
         error_setg(errp, "node-name=%s is conflicting with a device id",
                    node_name);
-        return;
+        goto out;
     }
 
     /* takes care of avoiding duplicates node names */
     if (bdrv_find_node(node_name)) {
         error_setg(errp, "Duplicate node name");
-        return;
+        goto out;
     }
 
     /* copy node name into the bs and insert it into the graph list */
     pstrcpy(bs->node_name, sizeof(bs->node_name), node_name);
     QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list);
+out:
+    g_free(gen_node_name);
 }
 
 static QemuOptsList bdrv_runtime_opts = {