Subject: Re: [NFS] [GIT] NFS client update for 2.6.16
From: Trond Myklebust <trond.myklebust@fys.uio.no>
To: Christoph Hellwig <hch@infradead.org>
Cc: Linus Torvalds <torvalds@osdl.org>, linux-kernel@vger.kernel.org,
       nfs@lists.sourceforge.net, nfsv4@linux-nfs.org
In-Reply-To: <20060321185734.GB19125@infradead.org>
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	 <20060321185734.GB19125@infradead.org>
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Date: Tue, 21 Mar 2006 14:06:20 -0500
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On Tue, 2006-03-21 at 18:57 +0000, Christoph Hellwig wrote:
> On Tue, Mar 21, 2006 at 01:08:52PM -0500, Trond Myklebust wrote:
> > We never had support for multiple iovecs in O_DIRECT, but were passing
> > around a single iovec entry deep into code that couldn't care less.
> 
> anthing that moves from iovecs back to plain buffers is counterproductive.
> The plan is that every fullblown fs will only deal with iovecs, onlt drivers
> and synthetic filesystems will implement the plain buffers.

You need to do more than just add an iovec argument to
nfs_file_direct_read()/nfs_file_direct_write() if you want to achieve
this. The new call interface actually just clarifies something that was
implicit in the old one.

As I said in my other posting, I believe Chuck's changes are relatively
orthogonal to what you want to do: they neither make the low-level
plumbing better or worse for readv()/writev().

We'd be happy to work with you in the run-up to 2.6.18 to add
multi-segment support for the existing patchsets. It makes more sense to
me to append that functionality to the existing patchsets rather than
trigger a complete rewrite (and thus have a sh_tload more code to
retest).

Cheers,
    Trond

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