Re: 2.6.38: Quota over NFS4

["J. Bruce Fields" <bfields@fieldses.org>]

On Thu, Mar 17, 2011 at 10:33:03PM +0100, Adam Lackorzynski wrote:
> 
> On Thu Mar 17, 2011 at 13:38:05 -0400, J. Bruce Fields wrote:
> > On Thu, Mar 17, 2011 at 02:32:47PM +0100, Adam Lackorzynski wrote:
> > > Hello,
> > > 
> > > I'm seeing a problem with quotas in a system where the server running
> > > 2.6.38 exports an XFS filesystem via NFS4 to a client. The client kernel
> > > version does not seem to play a role, checked with 2.6.38, 2.6.37 and
> > > 2.6.36. The following script and output show the problem:
> > > 
> > > #! /bin/sh
> > > 
> > > quota | grep home
> > > du
> > > cp /bin/ls x1
> > > du
> > > cat x1 > /dev/null
> > > rm x1
> > > du
> > > quota | grep home
> > > 
> > > Output:
> > > 
> > >    homes:/home/ 8194720  9072000 9174400          403670  500000  550000        
> > > 0       .
> > > 96      .
> > > 0       .
> > >    homes:/home/ 8194816  9072000 9174400          403671  500000  550000        
> > > 
> > > 
> > > As can be seen the 96 kb are still accounted on the quota of the user.
> > > Removing the 'cat' command from the script makes the quota be ok again
> > > (original value). Also mounting via nfs3 does not exhibit it, same for running
> > > the script on the nfs-server directly.
> > 
> > Does "df" show the same problem?
> 
> With '/bin/ls' it does not change at all, so I took a bigger binary
> which yields to:
> 
>    homes:/home/ 8203780  9072000 9174400          403688  500000  550000        
> 0       .
> Filesystem           1K-blocks      Used Available Use% Mounted on
>   homes:/home        513671168 335251456 178419712  66% /tmp/xx
> 4592    .
> Filesystem           1K-blocks      Used Available Use% Mounted on
>   homes:/home        513671168 335256576 178414592  66% /tmp/xx
> 0       .
> Filesystem           1K-blocks      Used Available Use% Mounted on
>   homes:/home        513671168 335256576 178414592  66% /tmp/xx
>    homes:/home/ 8208372  9072000 9174400          403689  500000  550000        
> 
> So yes, it seems to be there as well.

It might be easier to see with "df -i" (assuming we're leaking an
inode).

> > And does unmounting/remounting on the
> > client clear the problem?
> 
> No.
> 
> > (Or that, in combination with stopping the
> > server, unmounting the xfs export, remounting it, and restarting?)
> 
> I rebooted once, got a recovery and then the quotas were ok again (and
> supposedly the used blocks as well). I assume a unmount/mount would show
> the same behaviour but requires a bit of preparation to try out.
> 
> > Was there an earlier server version that didn't exhibit this problem?
> 
> Had 2.6.37 on the server before and that was fine regarding this.

OK, thanks.  Sounds like a server bug, but I'm not managing to reproduce
it here yet....

--b.