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On Sunday 31 October 2010 01:16:02 Simon Horman wrote:
> On Sat, Oct 30, 2010 at 05:55:32PM +0300, Julian Anastasov wrote:
> >
[ snip ]
> >
> > - What is the right thing to do in ip_vs_conn_fill_param_sync
> > when ip_vs_pe_get() does not find PE? May be to drop
> > connection? May be in ip_vs_process_message() we should
> > use one pointer for end of message (it was 'p' before now),
> > so that we can skip connections, for example, when some
> > mandatory parameter as PE is not supported. We should not
> > drop the whole sync message. When message is invalid it
> > should be dropped but lack of support should not hurt
> > other connections. In the case for PE may be
> > ip_vs_conn_fill_param_sync() should return 1 if
> > PE is unknown (ip_vs_pe_get). Then caller will continue
> > with next connection if result > 0 or will drop message
> > if result < 0 as in current patch. May be the pe_name
> > presence should be the first check in
> > ip_vs_conn_fill_param_sync.
>
> Yes, I agree with this.
I will fix that.
>
> > Also note that p->pe is
> > pointer without reference while called in ip_vs_sched_persist.
> > In our case with ip_vs_conn_fill_param_sync we should
> > put this reference after calling ip_vs_proc_conn().
> > May be ip_vs_find_dest should check that p->pe matches
> > svc->pe. ip_vs_try_bind_dest should provide p->pe too
> > for this check. But we must somehow ignore new conns
> > with PE if they don't have cp->dest (service) because
> > it is risky to attach PE that is not held by svc.
> > It is bad that the check for p->pe is before
> > ip_vs_find_dest.
>
> I have a patch, "IPVS: Add persistence engine to connection entry"
> that attaches the pe to the connection rather than the dest.
> In this case, if pe is NULL, then the connection doesn't use
> pe, which is fine. If its non-NULL, its there so there is no
> problem in that case either.
>
> I think this resolves the issue that you raise.
As mention before I will include that patch.
[ snip ]
> >
> > - Note that pe_data is leaked when ip_vs_proc_conn() fails
> > to create connection. May be PE info for non-templates
> > should be ignored?
>
> Yes I think it should be ignored in that case.
OK
>
> > And we need a way to know if
> > ip_vs_proc_conn called ip_vs_conn_new at all and that
> > it succeeded so that we can safely free pe_data.
>
> Perhaps ip_vs_proc_conn() could just free pe_data if
> it is present but ip_vs_conn_new() is not called.
>
Hmmm, I missed that one....
> >
> > Simon should tell what happens if some PE updates
> > ct->pe_data, may be we should replace it too for the
> > case when ip_vs_proc_conn works with existing template?
>
> At this stage there is no facility for updating PE data.
> But I think replacing it should be fine, so long as
> the appropriate locking is in place.
OK
>
> > v2 PATCH 4/4
> > May be we should add configuration option if sync is enabled
> > to default to version 0 because how we solve the problem if
> > backup can not be upgraded?
>
> I think that defaulting to v1 and having an option
> to move back to v0 would make more sense. Initially
> I would expect people to need to use v0 for the reason
> that you describe. But once the backup has been upgraded then,
> bugs not withstanding, there shouldn't be a reason not to use v1
> moving forward.
OK, but then I need to add sending of version_0
[ snip ]
I will start cooking a v3 soon
--
Regards
Hans Schillstrom <hans.schillstrom@xxxxxxxxxxxx>
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