From: Andreas Dilger <adilger@clusterfs.com>
To: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: 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
Subject: Re: NFSv4/pNFS possible POSIX I/O API standards
Date: Sat, 2 Dec 2006 17:57:14 -0800 [thread overview]
Message-ID: <20061203015714.GB5656@schatzie.adilger.int> (raw)
In-Reply-To: <1164996475.5761.150.camel@lade.trondhjem.org>
On Dec 01, 2006 13:07 -0500, Trond Myklebust wrote:
> > The more interesting case is multiple clients in the same directory. In
> > order to provide strong consistency, both stat() and readdir() have to
> > talk to the server (or more complicated leasing mechanisms are needed).
>
> Why would that be interesting? What applications do you have that
> require strong consistency in that scenario? I keep looking for uses for
> strong cache consistency with no synchronisation, but I have yet to meet
> someone who has an actual application that relies on it.
To be honest, I can't think of any use that actually _requires_ consistency
from stat() or readdir(), because even if the data was valid in the kernel
at the time it was gathered, there is no guarantee all the files haven't
been deleted by another thread even before the syscall is complete. Any
pretending that the returned data is "current" is a pipe dream.
Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.
next prev parent reply other threads:[~2006-12-03 1:57 UTC|newest]
Thread overview: 124+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-11-28 4:34 NFSv4/pNFS possible POSIX I/O API standards Gary Grider
2006-11-28 5:54 ` Christoph Hellwig
2006-11-28 10:54 ` Andreas Dilger
2006-11-28 11:28 ` Anton Altaparmakov
2006-11-28 20:17 ` Russell Cattelan
2006-11-28 23:28 ` Wendy Cheng
2006-11-29 9:12 ` Christoph Hellwig
2006-11-29 9:04 ` Christoph Hellwig
2006-11-29 9:14 ` Christoph Hellwig
2006-11-29 9:48 ` Andreas Dilger
2006-11-29 10:18 ` Anton Altaparmakov
2006-11-29 8:26 ` Brad Boyer
2006-11-30 9:25 ` Christoph Hellwig
2006-11-30 17:49 ` Sage Weil
2006-12-01 5:26 ` Trond Myklebust
2006-12-01 7:08 ` Sage Weil
2006-12-01 14:41 ` Trond Myklebust
2006-12-01 16:47 ` Sage Weil
2006-12-01 18:07 ` Trond Myklebust
2006-12-01 18:42 ` Sage Weil
2006-12-01 19:13 ` Trond Myklebust
2006-12-01 20:32 ` Sage Weil
2006-12-04 18:02 ` Peter Staubach
2006-12-05 23:20 ` readdirplus() as possible POSIX I/O API Sage Weil
2006-12-06 15:48 ` Peter Staubach
2006-12-03 1:57 ` Andreas Dilger [this message]
2006-12-03 7:34 ` NFSv4/pNFS possible POSIX I/O API standards Kari Hurtta
2006-12-03 1:52 ` Andreas Dilger
2006-12-03 16:10 ` Sage Weil
2006-12-04 7:32 ` Andreas Dilger
2006-12-04 15:15 ` Trond Myklebust
2006-12-05 0:59 ` Rob Ross
2006-12-05 4:44 ` Gary Grider
2006-12-05 10:05 ` Christoph Hellwig
2006-12-05 5:56 ` Trond Myklebust
2006-12-05 10:07 ` Christoph Hellwig
2006-12-05 14:20 ` Matthew Wilcox
2006-12-06 15:04 ` Rob Ross
2006-12-06 15:44 ` Matthew Wilcox
2006-12-06 16:15 ` Rob Ross
2006-12-05 14:55 ` Trond Myklebust
2006-12-05 22:11 ` Rob Ross
2006-12-05 23:24 ` Trond Myklebust
2006-12-06 16:42 ` Rob Ross
2006-12-06 12:22 ` Ragnar Kjørstad
2006-12-06 15:14 ` Trond Myklebust
2006-12-05 16:55 ` Latchesar Ionkov
2006-12-05 22:12 ` Christoph Hellwig
2006-12-06 23:12 ` Latchesar Ionkov
2006-12-06 23:33 ` Trond Myklebust
2006-12-05 21:50 ` Rob Ross
2006-12-05 22:05 ` Christoph Hellwig
2006-12-05 23:18 ` Sage Weil
2006-12-05 23:55 ` Ulrich Drepper
2006-12-06 10:06 ` Andreas Dilger
2006-12-06 17:19 ` Ulrich Drepper
2006-12-06 17:27 ` Rob Ross
2006-12-06 17:42 ` Ulrich Drepper
2006-12-06 18:01 ` Ragnar Kjørstad
2006-12-06 18:13 ` Ulrich Drepper
2006-12-17 14:41 ` Ragnar Kjørstad
2006-12-17 19:07 ` Ulrich Drepper
2006-12-17 19:38 ` Matthew Wilcox
2006-12-17 21:51 ` Ulrich Drepper
2006-12-18 2:57 ` Ragnar Kjørstad
2006-12-18 3:54 ` Gary Grider
2006-12-07 5:57 ` Andreas Dilger
2006-12-15 22:37 ` Ulrich Drepper
2006-12-16 18:13 ` Andreas Dilger
2006-12-16 19:08 ` Ulrich Drepper
2006-12-14 23:58 ` statlite() Rob Ross
2006-12-07 23:39 ` NFSv4/pNFS possible POSIX I/O API standards Nikita Danilov
2006-12-05 14:37 ` Peter Staubach
2006-12-05 10:26 ` readdirplus() as possible POSIX I/O API Andreas Dilger
2006-12-05 15:23 ` Trond Myklebust
2006-12-06 10:28 ` Andreas Dilger
2006-12-06 15:10 ` Trond Myklebust
2006-12-05 17:06 ` Latchesar Ionkov
2006-12-05 22:48 ` Rob Ross
2006-11-29 10:25 ` NFSv4/pNFS possible POSIX I/O API standards Steven Whitehouse
2006-11-30 12:29 ` Christoph Hellwig
2006-12-01 15:52 ` Ric Wheeler
2006-11-29 12:23 ` Matthew Wilcox
2006-11-29 12:35 ` Matthew Wilcox
2006-11-29 16:26 ` Gary Grider
2006-11-29 17:18 ` Christoph Hellwig
2006-11-29 12:39 ` Christoph Hellwig
2006-12-01 22:29 ` Rob Ross
2006-12-02 2:35 ` Latchesar Ionkov
2006-12-05 0:37 ` Rob Ross
2006-12-05 10:02 ` Christoph Hellwig
2006-12-05 16:47 ` Latchesar Ionkov
2006-12-05 17:01 ` Matthew Wilcox
[not found] ` <f158dc670612050909m366594c5ubaa87d9a9ecc8c2a@mail.gmail.com>
2006-12-05 17:10 ` Latchesar Ionkov
2006-12-05 17:39 ` Matthew Wilcox
2006-12-05 21:55 ` Rob Ross
2006-12-05 21:50 ` Peter Staubach
2006-12-05 21:44 ` Rob Ross
2006-12-06 11:01 ` openg Christoph Hellwig
2006-12-06 15:41 ` openg Trond Myklebust
2006-12-06 15:42 ` openg Rob Ross
2006-12-06 23:32 ` openg Christoph Hellwig
2006-12-14 23:36 ` openg Rob Ross
2006-12-06 23:25 ` Re: NFSv4/pNFS possible POSIX I/O API standards Latchesar Ionkov
2006-12-06 9:48 ` David Chinner
2006-12-06 15:53 ` openg and path_to_handle Rob Ross
2006-12-06 16:04 ` Matthew Wilcox
2006-12-06 16:20 ` Rob Ross
2006-12-06 20:57 ` David Chinner
2006-12-06 20:40 ` David Chinner
2006-12-06 20:50 ` Matthew Wilcox
2006-12-06 21:09 ` David Chinner
2006-12-06 22:09 ` Andreas Dilger
2006-12-06 22:17 ` Matthew Wilcox
2006-12-06 22:41 ` Andreas Dilger
2006-12-06 23:39 ` Christoph Hellwig
2006-12-14 22:52 ` Rob Ross
2006-12-06 20:50 ` Rob Ross
2006-12-06 21:01 ` David Chinner
2006-12-06 23:19 ` Latchesar Ionkov
2006-12-14 21:00 ` Rob Ross
2006-12-14 21:20 ` Matthew Wilcox
2006-12-14 23:02 ` Rob Ross
2006-11-28 15:08 ` NFSv4/pNFS possible POSIX I/O API standards Matthew Wilcox
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