Provide API for a node insertion to and removal from a backing chain.
Suggested-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
---
block.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
include/block/block.h | 3 +++
2 files changed, 52 insertions(+)
diff --git a/block.c b/block.c
index 430edf7..502b483 100644
--- a/block.c
+++ b/block.c
@@ -4670,6 +4670,55 @@ static void bdrv_delete(BlockDriverState *bs)
g_free(bs);
}
+BlockDriverState *bdrv_insert_node(BlockDriverState *bs, QDict *node_options,
+ int flags, Error **errp)
+{
+ BlockDriverState *new_node_bs;
+ Error *local_err = NULL;
+
+ new_node_bs = bdrv_open(NULL, NULL, node_options, flags, errp);
+ if (new_node_bs == NULL) {
+ error_prepend(errp, "Could not create node: ");
+ return NULL;
+ }
+
+ bdrv_drained_begin(bs);
+ bdrv_replace_node(bs, new_node_bs, &local_err);
+ bdrv_drained_end(bs);
+
+ if (local_err) {
+ bdrv_unref(new_node_bs);
+ error_propagate(errp, local_err);
+ return NULL;
+ }
+
+ return new_node_bs;
+}
+
+void bdrv_remove_node(BlockDriverState *bs)
+{
+ BdrvChild *child;
+ BlockDriverState *inferior_bs;
+
+ child = bdrv_filter_or_cow_child(bs);
+ if (!child) {
+ return;
+ }
+ inferior_bs = child->bs;
+
+ /* Retain the BDS until we complete the graph change. */
+ bdrv_ref(inferior_bs);
+ /* Hold a guest back from writing while permissions are being reset. */
+ bdrv_drained_begin(inferior_bs);
+ /* Refresh permissions before the graph change. */
+ bdrv_child_refresh_perms(bs, child, &error_abort);
+ bdrv_replace_node(bs, inferior_bs, &error_abort);
+
+ bdrv_drained_end(inferior_bs);
+ bdrv_unref(inferior_bs);
+ bdrv_unref(bs);
+}