Date: Thu, 16 Dec 1999 00:01:54 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: Kevin Day <toasty@dragondata.com> Cc: phk@critter.freebsd.dk (Poul-Henning Kamp), gallatin@cs.duke.edu (Andrew Gallatin), freebsd-current@FreeBSD.ORG Subject: Re: Serious server-side NFS problem Message-ID: <199912160801.AAA50074@apollo.backplane.com> References: <199912160758.BAA87332@celery.dragondata.com>
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:>
:> In message <199912160743.XAA49890@apollo.backplane.com>, Matthew Dillon writes:
:> >
:> >:> NFS uses the kernel 'boottime' structure to generate its version id.
:> >:> Now normally you might believe that this structure, once set, will
:> >:> never change. The authors of NFS certainly make that assumption!
:> >:
:> >:Is this another case of "lets assume the time of day is a random number" or
:> >:is there any underlying assumption about time in this ?
:> >:
:> >:--
:> >:Poul-Henning Kamp FreeBSD coreteam member
:> >:phk@FreeBSD.ORG "Real hackers run -current on their laptop."
:> >
:> > It basically needs to be a unique for each server reboot in order
:> > to allow clients to resynchronize.
:>
:> Ok, then I suggest that you cache a copy of the boottime in the NFS
:> code for this purpose.
:>
:
:Ack, I was using this very same thing for several devices in an isolated
:peer-to-peer network to decide who the 'master' was. (Whoever had been up
:longest knew more about the state of the network) Having this change could
:cause weirdness for me too... I assumed (without checking *thwap*) that
:boottime was a constant.
:
:Perhaps a 'real_boottime' or 'unadjusted_boottime' that gets copied after
:'boottime' gets initialized so that others can use it, not just NFS? :)
:
:
:Kevin
We're already testing a patch.
For the moment it is going to be NFS specific, because there's
no time right now to do it right.
Hopefully I can get this in tomorrow and be done with NFS for the
release. Then I can spend a little time figuring out what's
wrong with VN (which doesn't work in current at the moment). Again.
-Matt
Matthew Dillon
<dillon@backplane.com>
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