Re: 2.6.xx: NFS: directory motion/cam2 contains a readdir loop

[Trond Myklebust]

On Wed, 2011-07-27 at 16:37 -0400, Trond Myklebust wrote: 
> On Wed, 2011-07-27 at 15:47 -0400, Christoph Hellwig wrote: 
> > On Wed, Jul 27, 2011 at 03:44:20PM -0400, Justin Piszcz wrote:
> > > 
> > > 
> > > On Wed, 27 Jul 2011, Christoph Hellwig wrote:
> > > 
> > > >On Wed, Jul 27, 2011 at 03:35:01PM -0400, Justin Piszcz wrote:
> > > >>Currently I do not see any dupes, however I have a script that moves
> > > >>images out of the directory once an hour:
> > > >>0 * * * * /usr/local/bin/move_to_old2.sh > /dev/null 2>&1
> > > >
> > > >Do you keep adding files to the directory while you move files out?
> > > Yes, otherwise there are too many files in the directory and viewers, e.g.,
> > > each geeqie (picture viewer) will use > 4-6GB of memory, so I try to keep
> > > it around 5,000 pictures or less.
> > > 
> > > >What's the rate of additions/removals to the directory?
> > > Additions it depends, around 5,000 over a 12hr period, 416/hr, current:
> > > 
> > > atom:/d1/motion# find cam1|wc
> > >    5215    5215  166853
> > > atom:/d1/motion# find cam2|wc
> > >    5069    5069  162181
> > > atom:/d1/motion# find cam3|wc
> > >    5594    5594  178981
> > > atom:/d1/motion#
> > 
> > This sounds a lot like xfs simply filling up the directory index slots
> > of files that you just moved out with new files, and nfs falsely
> > claiming that this is a problem.
> 
> Yep. There is an existing bugzilla report for this bug at
> 
>    https://bugzilla.kernel.org/show_bug.cgi?id=38572
> 
> I have a preliminary patch there that attempts to turn off the loop
> detection when the directory is seen to change, however that patch still
> appears to have a bug in it, and I haven't had time to figure out what
> is wrong yet.
> 
> Can you perhaps take a look, Bryan?

Actually, Justin, can you test the following slight variant on the patch
in the bugzilla?

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