Re: [pve-devel] applied: [PATCH cluster] pmxcfs sync: properly check for corosync error

["Fabian Grünbichler" <f.gruenbichler@proxmox.com>]

> Thomas Lamprecht <t.lamprecht@proxmox.com> hat am 25.09.2020 15:23 geschrieben:
> 
>  
> On 25.09.20 14:53, Fabian Grünbichler wrote:
> > dfsm_send_state_message_full always returns != 0, since it returns
> > cs_error_t which starts with CS_OK at 1, with values >1 representing
> > errors.
> > 
> > Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
> > ---
> > unfortunately not that cause of Alexandre's shutdown/restart issue, but
> > might have caused some hangs as well since we would be stuck in
> > START_SYNC in that case..
> > 
> >  data/src/dfsm.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> >
> 
> applied, thanks! But as the old wrong code showed up as critical error
> "failed to send SYNC_START message" if it worked, it either (almost) never
> works here or is not a probable case, else we'd saw this earlier.
> 
> (still a valid and appreciated fix, just noting)

no, the old wrong code never triggered the error handling (log + leave), no matter whether the send worked or failed - the return value cannot be 0, so the condition is never true. if the send failed, the code assumed the state machine is now in START_SYNC mode and waits for STATE messages, which will never come since the other nodes haven't switched to START_SYNC..

it would still show up in the logs since cpg_mcast_joined failure is always verbose in the logs, but it would not be obvious that it caused the state machine to take a wrong turn I think.