block: Use bdrv_recurse_can_replace()
Let check_to_replace_node() use the more specialized
bdrv_recurse_can_replace() instead of
bdrv_recurse_is_first_non_filter(), which is too restrictive (or, in the
case of quorum, sometimes not restrictive enough).
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200218103454.296704-10-mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block.c b/block.c
index e2fefe5..80a0806 100644
--- a/block.c
+++ b/block.c
@@ -6272,6 +6272,17 @@
return false;
}
+/*
+ * Check whether the given @node_name can be replaced by a node that
+ * has the same data as @parent_bs. If so, return @node_name's BDS;
+ * NULL otherwise.
+ *
+ * @node_name must be a (recursive) *child of @parent_bs (or this
+ * function will return NULL).
+ *
+ * The result (whether the node can be replaced or not) is only valid
+ * for as long as no graph or permission changes occur.
+ */
BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
const char *node_name, Error **errp)
{
@@ -6296,8 +6307,11 @@
* Another benefit is that this tests exclude backing files which are
* blocked by the backing blockers.
*/
- if (!bdrv_recurse_is_first_non_filter(parent_bs, to_replace_bs)) {
- error_setg(errp, "Only top most non filter can be replaced");
+ if (!bdrv_recurse_can_replace(parent_bs, to_replace_bs)) {
+ error_setg(errp, "Cannot replace '%s' by a node mirrored from '%s', "
+ "because it cannot be guaranteed that doing so would not "
+ "lead to an abrupt change of visible data",
+ node_name, parent_bs->node_name);
to_replace_bs = NULL;
goto out;
}
