From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@infradead.org>
Subject: Re: NFSv4/pNFS possible POSIX I/O API standards
Date: Tue, 5 Dec 2006 10:07:48 +0000
Message-ID: <20061205100748.GC5871@infradead.org>
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Cc: Rob Ross <rross@mcs.anl.gov>,
	Andreas Dilger <adilger@clusterfs.com>,
	Sage Weil <sage@newdream.net>,
	Christoph Hellwig <hch@infradead.org>,
	Brad Boyer <flar@allandria.com>,
	Anton Altaparmakov <aia21@cam.ac.uk>,
	Gary Grider <ggrider@lanl.gov>, linux-fsdevel@vger.kernel.org
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To: Trond Myklebust <trond.myklebust@fys.uio.no>
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On Tue, Dec 05, 2006 at 12:56:40AM -0500, Trond Myklebust wrote:
> On Mon, 2006-12-04 at 18:59 -0600, Rob Ross wrote:
> > Hi all,
> > 
> > I don't think that the group intended that there be an opendirplus(); 
> > rather readdirplus() would simply be called instead of the usual 
> > readdir(). We should clarify that.
> > 
> > Regarding Peter Staubach's comments about no one ever using the 
> > readdirplus() call; well, if people weren't performing this workload in 
> > the first place, we wouldn't *need* this sort of call! This call is 
> > specifically targeted at improving "ls -l" performance on large 
> > directories, and Sage has pointed out quite nicely how that might work.
> 
> ...and we have pointed out how nicely this ignores the realities of
> current caching models. There is no need for a  readdirplus() system
> call. There may be a need for a caching barrier, but AFAICS that is all.

I think Andreas mentioned that it is useful for clustered filesystems
that can avoid additional roundtrips this way.  That alone might now
be enough reason for API additions, though.  The again statlite and
readdirplus really are the most sane bits of these proposals as they
fit nicely into the existing set of APIs.  The filehandle idiocy on
the other hand is way of into crackpipe land.