From: Benny Halevy <bhalevy@panasas.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: linux-nfs@vger.kernel.org, nfsv4@ietf.org
Subject: Re: [nfsv4] layoutcommits and file layout
Date: Mon, 03 Jan 2011 16:21:07 +0200 [thread overview]
Message-ID: <4D21DB53.9050104@panasas.com> (raw)
In-Reply-To: <20101216230707.GB16760@infradead.org>
On 2010-12-17 01:07, Christoph Hellwig wrote:
> On Thu, Dec 16, 2010 at 11:21:21AM -0500, Matt W. Benjamin wrote:
>> Hi,
>>
>> We have a files implementation which wants to receive LAYOUTCOMMIT when a client is finished with a layout. It was my clear understanding from rfc5661 that we could expect this behavior.
>
> Care to post it to the list?
>
I don't know what Matt's server is doing but the fundamental problem is
manifested with extending a file with parallel DS writes.
Assuming that the DS writes are executed in arbitrary order,
exposing the file length before LAYOUTCOMMIT can cause
a concurrent reader to read a hole. Although locking can
solve this case, day-to-day applications that work well over
local filesystem and legacy NFS may break because of this.
Benny
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next prev parent reply other threads:[~2011-01-03 14:21 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <978693366.32.1292516428080.JavaMail.root@thunderbeast.private.linuxbox.com>
2010-12-16 16:21 ` [nfsv4] layoutcommits and file layout Matt W. Benjamin
[not found] ` <1740153586.34.1292516481789.JavaMail.root-DQa+Qhn4Z593Hjf6844flrbbgpPoC6wPvwx5bNz670MAvxtiuMwx3w@public.gmane.org>
2010-12-16 23:07 ` Christoph Hellwig
2011-01-03 14:21 ` Benny Halevy [this message]
2011-01-03 14:40 ` Trond Myklebust
2011-01-05 19:01 ` Benny Halevy
2011-01-05 19:04 ` Trond Myklebust
2011-01-05 19:14 ` Trond Myklebust
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