From: Benny Halevy <bhalevy@panasas.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Rees <rees@citi.umich.edu>, linux-nfs@vger.kernel.org
Subject: Re: [RFC] spnfs-block: restore i_op->fallocate
Date: Thu, 31 Mar 2011 08:53:58 +0200 [thread overview]
Message-ID: <4D942506.1020505@panasas.com> (raw)
In-Reply-To: <20110330173344.GA24631@lst.de>
On 2011-03-30 19:33, Christoph Hellwig wrote:
> On Wed, Mar 30, 2011 at 07:11:47PM +0200, Benny Halevy wrote:
>> Makes sense. This could also be done by adding a respective flags argument
>> to fallocate and have a common wrapper function look at the file descriptor
>> and call the fs fallocate, that could then get the inode rather the file.
>> In other words, why copy code rather than factor it out into a common
>> function?
> We can discuss that _iff_ a valid use for a file-less fallocate appears
> in mainline. The pnfs-block one is not. It's just a racy hack, which
> opens gapping holes. Take a look what it does - it allocates block for
> a client to write into directly, with absolutely zero guarantee the
> block allocation actually stays around until that point.
>
> You'll need to have some outstanding token on extent map changes like
> done in CXFS or NEC's "gfs" which implemented something similar to pnfs
> based on nfsv3.
Agreed.
Benny
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next prev parent reply other threads:[~2011-03-31 6:54 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1301500460-16467-1-git-send-email-bhalevy@panasas.com>
2011-03-30 15:58 ` [RFC] spnfs-block: restore i_op->fallocate Christoph Hellwig
2011-03-30 17:11 ` Benny Halevy
2011-03-30 17:33 ` Christoph Hellwig
2011-03-31 6:53 ` Benny Halevy [this message]
2011-03-31 13:53 ` Christoph Hellwig
2011-04-01 8:30 ` Benny Halevy
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