block: Add replaces argument to drive-mirror
drive-mirror will bdrv_swap the new BDS named node-name with the one
pointed by replaces when the mirroring is finished.
Signed-off-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block.c b/block.c
index 106238d..9ecadf0 100644
--- a/block.c
+++ b/block.c
@@ -5766,3 +5766,28 @@
return false;
}
+
+BlockDriverState *check_to_replace_node(const char *node_name, Error **errp)
+{
+ BlockDriverState *to_replace_bs = bdrv_find_node(node_name);
+ if (!to_replace_bs) {
+ error_setg(errp, "Node name '%s' not found", node_name);
+ return NULL;
+ }
+
+ if (bdrv_op_is_blocked(to_replace_bs, BLOCK_OP_TYPE_REPLACE, errp)) {
+ return NULL;
+ }
+
+ /* We don't want arbitrary node of the BDS chain to be replaced only the top
+ * most non filter in order to prevent data corruption.
+ * Another benefit is that this tests exclude backing files which are
+ * blocked by the backing blockers.
+ */
+ if (!bdrv_is_first_non_filter(to_replace_bs)) {
+ error_setg(errp, "Only top most non filter can be replaced");
+ return NULL;
+ }
+
+ return to_replace_bs;
+}