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From: Bruce Fields <bfields@fieldses.org>
To: Chuck Lever <chuck.lever@oracle.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>,
	Kevin Vasko <kvasko@gmail.com>,
	Linux NFS Mailing List <linux-nfs@vger.kernel.org>
Subject: Re: NFSv4 client locks up on larger writes with Kerberos enabled
Date: Thu, 26 Sep 2019 12:05:56 -0400	[thread overview]
Message-ID: <20190926160556.GC29192@fieldses.org> (raw)
In-Reply-To: <1BC54D7A-073E-40FD-9AA3-552F1E1BD214@oracle.com>

On Thu, Sep 26, 2019 at 08:55:17AM -0700, Chuck Lever wrote:
> > On Sep 25, 2019, at 1:07 PM, Bruce Fields <bfields@fieldses.org> wrote:
> > 
> > On Wed, Sep 25, 2019 at 11:49:14AM -0700, Chuck Lever wrote:
> >> Sounds like the NFS server is dropping the connection. With
> >> GSS enabled, that's usually a sign that the GSS window has
> >> overflowed.
> > 
> > Would that show up in the rpc statistics on the client somehow?
> 
> More likely on the server. The client just sees a disconnect
> without any explanation attached.

So watching a count of disconnects might at least tell us something?

> gss_verify_header is where the checking is done on the server.
> Disappointingly, I see some dprintk's in there, but no static
> trace events.

Kevin, was this a Linux server?

--b.

> > In that case--I seem to remember there's a way to configure the size of
> > the client's slot table, maybe lowering that (decreasing the number of
> > rpc's allowed to be outstanding at a time) would work around the
> > problem.
> 
> > Should the client be doing something different to avoid or recover from
> > overflows of the gss window?
> 
> The client attempts to meter the request stream so that it stays
> within the bounds of the GSS sequence number window. The stream
> of requests is typically unordered coming out of the transmit
> queue.
> 
> There is some new code (since maybe v5.0?) that handles the
> metering: gss_xmit_need_reencode().

  reply	other threads:[~2019-09-26 16:05 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-18 23:36 NFSv4 client locks up on larger writes with Kerberos enabled Kevin Vasko
     [not found] ` <E172CA50-EC89-4072-9C1D-1B825DC3FE8B@lysator.liu.se>
2019-09-19 14:19   ` Kevin Vasko
     [not found]     ` <72E82F62-C743-4783-B81E-98E6A8E35738@lysator.liu.se>
2019-09-19 14:58       ` Kevin Vasko
2019-09-25 16:48 ` J. Bruce Fields
2019-09-25 17:06   ` Chuck Lever
2019-09-25 18:44     ` Kevin Vasko
2019-09-25 18:49       ` Chuck Lever
2019-09-25 19:10         ` Kevin Vasko
2019-09-25 20:07         ` Bruce Fields
2019-09-26 15:55           ` Chuck Lever
2019-09-26 16:05             ` Bruce Fields [this message]
2019-09-26 19:55             ` Bruce Fields
2019-09-30 14:51               ` Kevin Vasko
2019-09-30 16:19                 ` Bruce Fields
2019-09-26  7:30       ` Daniel Kobras
2019-09-26 16:25 Kevin Vasko

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