From: Trond Myklebust <Trond.Myklebust@netapp.com>
To: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Bryan Schumaker <bjschuma@netapp.com>,
"linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH 3/3] NFS: Detect loops in a readdir due to bad cookies
Date: Wed, 23 Mar 2011 14:34:03 -0400 [thread overview]
Message-ID: <1300905243.11677.53.camel@lade.trondhjem.org> (raw)
In-Reply-To: <20110323182524.GB25284@fieldses.org>
On Wed, 2011-03-23 at 14:25 -0400, J. Bruce Fields wrote:
> On Wed, Mar 23, 2011 at 01:39:44PM -0400, Bryan Schumaker wrote:
> > Some filesystems (such as ext4) can return the same cookie value for multiple
>
> Do the ext4 people know about this? (And what's the easiest way to
> reproduce it?)
They are aware of it. I don't know if they are aware how easy it is to
reproduce.
Bryan saw several 10s of instances of duplicate cookies when he was
doing performance testing of readdir on a directory with 10^6 entries.
Most of the time it didn't cause looping on the client since the looping
behaviour depends on the distribution of those cookies in the client's
readdir cache. However on occasion he did see looping in the client, and
at least once he saw looping on the server too (in which a duplicate
cookie caused the server to return files that it had already sent to the
client).
--
Trond Myklebust
Linux NFS client maintainer
NetApp
Trond.Myklebust@netapp.com
www.netapp.com
next prev parent reply other threads:[~2011-03-23 18:34 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-23 17:39 [PATCH 3/3] NFS: Detect loops in a readdir due to bad cookies Bryan Schumaker
2011-03-23 18:10 ` peter.staubach
2011-03-23 18:17 ` Trond Myklebust
2011-03-23 18:11 ` Trond Myklebust
2011-03-23 18:25 ` J. Bruce Fields
2011-03-23 18:34 ` Trond Myklebust [this message]
2011-03-23 18:42 ` peter.staubach
2011-03-23 18:48 ` Trond Myklebust
2011-03-23 21:27 ` NeilBrown
2011-03-23 21:36 ` Daniel.Muntz
2011-03-23 21:55 ` NeilBrown
2011-03-23 18:43 ` peter.staubach
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