[Drbd-dev] [PATCH] drbd: fix a bug with two-primaries configuration

[Drbd-dev] [PATCH] drbd: fix a bug with two-primaries configuration

[Rui Xu]

There is a bug when execute 'drbdsetup disconnect' in
two-primaries configuration.

When 'drbdsetup disconnect' is called by user, two primary
nodes will going to outdated in do_change_cstate, then the
command will failed since there is no UpToDate node.

Fix it by modify the judgment condition in do_change_cstate.

Signed-off-by: Rui Xu <rui.xu@easystack.cn>
---
 drbd/drbd_state.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drbd/drbd_state.c b/drbd/drbd_state.c
index 792a96d5..c4f3f776 100644
--- a/drbd/drbd_state.c
+++ b/drbd/drbd_state.c
@@ -5406,7 +5406,7 @@ static bool do_change_cstate(struct change_context *context, enum change_phase p
 		u64 directly_reachable = directly_connected_nodes(resource, NEW) |
 			NODE_MASK(resource->res_opts.node_id);
 
-		if (reply->primary_nodes & ~directly_reachable)
+		if (!(reply->primary_nodes & directly_reachable))
 			__outdate_myself(resource);
 	}
 
-- 
2.25.1

Re: [Drbd-dev] [PATCH] drbd: fix a bug with two-primaries configuration

[Joel Colledge]

The behavior that you describe is the intended behavior, I believe. If
you have two primaries and want to disconnect them in a controlled
fashion, you should demote them first.

As discussed previously, you probably should not be using
"allow-two-primaries" at all.

The proposed patch unfortunately also breaks various other usage
scenarios. For instance, if you have two nodes that are both Secondary
and UpToDate, and run 'drbdsetup disconnect', it will cause them to
become Outdated.

Best regards,
Joel

Re: [Drbd-dev] [PATCH] drbd: fix a bug with two-primaries configuration

[rui.xu]

[-- Attachment #1: Type: text/plain, Size: 923 bytes --]

Hi Joel,
  Thanks for the reply. It is indeed a intended behavior and i will discard the patch.

Thanks,
Xu







From: Joel Colledge <joel.colledge@linbit.com>
Date: 2022-08-01 22:22:12
To:  Rui Xu <rui.xu@easystack.cn>
Cc:  Philipp Reisner <philipp.reisner@linbit.com>,drbd-dev@lists.linbit.com,dongsheng.yang@easystack.cn
Subject: Re: [PATCH] drbd: fix a bug with two-primaries configuration>The behavior that you describe is the intended behavior, I believe. If
>you have two primaries and want to disconnect them in a controlled
>fashion, you should demote them first.
>
>As discussed previously, you probably should not be using
>"allow-two-primaries" at all.
>
>The proposed patch unfortunately also breaks various other usage
>scenarios. For instance, if you have two nodes that are both Secondary
>and UpToDate, and run 'drbdsetup disconnect', it will cause them to
>become Outdated.
>
>Best regards,
>Joel





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