From: Lukas Hejtmanek <xhejtman@ics.muni.cz>
To: "William A. (Andy) Adamson" <androsadamson@gmail.com>
Cc: linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, salvet@ics.muni.cz
Subject: Re: Deadlock in NFSv4 in all kernels
Date: Tue, 25 May 2010 16:02:40 +0200 [thread overview]
Message-ID: <20100525140240.GG9731@ics.muni.cz> (raw)
In-Reply-To: <AANLkTimsQTYWndbQo2nU01pcJfTRSZlPCMEY8m-CnksM@mail.gmail.com>
On Tue, May 25, 2010 at 09:45:32AM -0400, William A. (Andy) Adamson wrote:
> Not get into the problem in the first place: this means
>
> 1) determine a 'lead time' where the NFS client declares a context
> expired even though it really as 'lead time' until it actually
> expires.
>
> 2) flush all writes on any contex that will expire within the lead
> time which needs to be long enough for flushes to take place.
I think you cannot give any guarantees that the flush happens on time. There
can be server overload, network overload, anything and you are out of luck.
--
Lukáš Hejtmánek
WARNING: multiple messages have this Message-ID (diff)
From: Lukas Hejtmanek <xhejtman-8qz54MUs51PtwjQa/ONI9g@public.gmane.org>
To: "William A. (Andy) Adamson"
<androsadamson-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
salvet-8qz54MUs51PtwjQa/ONI9g@public.gmane.org
Subject: Re: Deadlock in NFSv4 in all kernels
Date: Tue, 25 May 2010 16:02:40 +0200 [thread overview]
Message-ID: <20100525140240.GG9731@ics.muni.cz> (raw)
In-Reply-To: <AANLkTimsQTYWndbQo2nU01pcJfTRSZlPCMEY8m-CnksM-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
On Tue, May 25, 2010 at 09:45:32AM -0400, William A. (Andy) Adamson wrote:
> Not get into the problem in the first place: this means
>
> 1) determine a 'lead time' where the NFS client declares a context
> expired even though it really as 'lead time' until it actually
> expires.
>
> 2) flush all writes on any contex that will expire within the lead
> time which needs to be long enough for flushes to take place.
I think you cannot give any guarantees that the flush happens on time. There
can be server overload, network overload, anything and you are out of luck.
--
Lukáš Hejtmánek
--
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next prev parent reply other threads:[~2010-05-25 14:02 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-07 15:39 Deadlock in NFSv4 in all kernels Lukas Hejtmanek
2010-05-07 15:39 ` Lukas Hejtmanek
2010-05-24 21:24 ` Pavel Machek
2010-05-25 12:28 ` Trond Myklebust
2010-05-25 12:58 ` Lukas Hejtmanek
2010-05-25 13:39 ` Trond Myklebust
2010-05-25 13:39 ` Trond Myklebust
2010-05-25 14:07 ` Zdenek Salvet
2010-05-25 14:07 ` Zdenek Salvet
2010-05-25 17:10 ` Sunil Mushran
2010-05-25 17:10 ` Sunil Mushran
2010-05-25 13:45 ` William A. (Andy) Adamson
2010-05-25 13:45 ` William A. (Andy) Adamson
2010-05-25 14:02 ` Lukas Hejtmanek [this message]
2010-05-25 14:02 ` Lukas Hejtmanek
2010-05-25 14:10 ` William A. (Andy) Adamson
2010-05-25 14:10 ` William A. (Andy) Adamson
2010-05-25 14:29 ` Trond Myklebust
2010-05-25 14:29 ` Trond Myklebust
2010-05-25 14:04 ` Trond Myklebust
2010-05-25 14:04 ` Trond Myklebust
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