Daniel P. Berrangé <[email protected]> writes:
> While most objects can perform all their cleanup in the finalizer
> method, there can be interactions with other resources / subsystems
> / threads which require that some cleanup be performed on an user
> creatable object before unparenting it and entering finalization.
>
> The current 'can_be_deleted' method runs in the deletion path and
> is intended to be used to block deletion. While it could be used
> to perform cleanup tasks, its name suggests it should be free of
> side-effects.
>
> Generalize this by renaming it to 'prepare_delete', explicitly
> allowing for cleanup to be provided. Existing users of 'can_be_deleted'
> are re-written, which provides them with more detailed/tailored error
> messages.
Old message:
error_setg(errp, "object '%s' is in use, can not be deleted", id);
New messages:
error_setg(errp, "Cryptodev backend '%s' is still in use",
error_setg(errp, "Host memory backend '%s' is still mapped",
error_setg(errp, "IOMMUFD backend '%s' still has %d users",
error_setg(errp, "Throttle group '%s' still has multiple references",
error_setg(errp, "Deleting CAN bus device '%s' is not supported",
error_setg(errp, "Deleting main loop '%s' is not supported",
All now mention what kind of object it is. Users could probably figure
this out from context easily. Welcome small improvement.
The two unconditional ones become more accurate: they now report "not
supported" instead of "in use".
The other four lose "can not be deleted". Users can probably figure
this out from context. Still, I lean towards error messages like "Can't
DO-SOMETHING because REASON" until that becomes overly verbose. What do
you think?
> Signed-off-by: Daniel P. Berrangé <[email protected]>
[...]
> diff --git a/qom/object_interfaces.c b/qom/object_interfaces.c
> index 7080f85f95..ac992aa786 100644
> --- a/qom/object_interfaces.c
> +++ b/qom/object_interfaces.c
> @@ -32,16 +32,15 @@ bool user_creatable_complete(UserCreatable *uc, Error
> **errp)
> return !*errp;
> }
>
> -bool user_creatable_can_be_deleted(UserCreatable *uc)
> +bool user_creatable_prepare_delete(UserCreatable *uc, Error **errp)
> {
> -
> UserCreatableClass *ucc = USER_CREATABLE_GET_CLASS(uc);
> + ERRP_GUARD();
No longer necessary.
>
> - if (ucc->can_be_deleted) {
> - return ucc->can_be_deleted(uc);
> - } else {
> - return true;
> + if (ucc->prepare_delete) {
> + return ucc->prepare_delete(uc, errp);
> }
> + return true;
> }
>
> void user_creatable_add_qapi(ObjectOptions *options, Error **errp)
> @@ -253,8 +252,7 @@ bool user_creatable_del(const char *id, Error **errp)
> return false;
> }
>
> - if (!user_creatable_can_be_deleted(USER_CREATABLE(obj))) {
> - error_setg(errp, "object '%s' is in use, can not be deleted", id);
> + if (!user_creatable_prepare_delete(USER_CREATABLE(obj), errp)) {
> return false;
> }
>
[...]
