[Drbd-dev] [PATCH] drbd: when change susp_uuid[NEW] to true, make sure susp_uuid[OLD] is false

["zhengbing.huang" <zhengbing.huang@easystack.cn>]

The problem scenario is as follows:

1. drbd is built on two nodes, role is primary and secondary, quorum is 2.
   then drbd's network fails. IO will be suspended.
2. primary modify quorum to 1, during this state change,
   drbd will set susp_uuid[NEW] to true and generate a new UUID.
3. then in w_after_state_change, start the second state change,
   set susp_uuid[NEW] to false. but during the second state change,
   it's possible to find NEW_CUR_UUID flag was set by others.
   then sanitize_state() will set susp_uuid[NEW] to true.

Finally susp_uuid value is {true, true}, IO is frozen.
And there is no way to set susp_uuid to false after that.

So, while susp_uuid[NEW] is set to true, we want susp_uuid[OLD] to be false.

Fixes: d47f7456ab ("drbd: create new UUID before resuming IO upon regaining quorum")
Signed-off-by: zhengbing.huang <zhengbing.huang@easystack.cn>
---
 drbd/drbd_state.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drbd/drbd_state.c b/drbd/drbd_state.c
index e35150340..0dedd2dae 100644
--- a/drbd/drbd_state.c
+++ b/drbd/drbd_state.c
@@ -2356,6 +2356,7 @@ static void sanitize_state(struct drbd_resource *resource)
 	if (resource_is_suspended(resource, OLD) && !resource_is_suspended(resource, NEW)) {
 		idr_for_each_entry(&resource->devices, device, vnr) {
 			if (test_bit(NEW_CUR_UUID, &device->flags)) {
+				resource->susp_uuid[OLD] = false;
 				resource->susp_uuid[NEW] = true;
 				break;
 			}
-- 
2.17.1