BlockDriverState *check_to_replace_node(const char *node_name, Error **errp) { BlockDriverState *to_replace_bs = bdrv_find_node(node_name); AioContext *aio_context; if (!to_replace_bs) { error_setg(errp, "Node name '%s' not found", node_name); return NULL; } aio_context = bdrv_get_aio_context(to_replace_bs); aio_context_acquire(aio_context); if (bdrv_op_is_blocked(to_replace_bs, BLOCK_OP_TYPE_REPLACE, errp)) { to_replace_bs = NULL; goto out; } /* 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"); to_replace_bs = NULL; goto out; } out: aio_context_release(aio_context); return to_replace_bs; }