NFS+ZFS+nullfs on Server random Permission Denied errors on client (nfsv4)

Rick Macklem rmacklem at uoguelph.ca
Sun Jun 2 12:30:52 UTC 2013


Dmitry Morozovsky wrote:
> On Wed, 29 May 2013, Rick Macklem wrote:
> 
> > Bryan Drewery wrote:
> > > Server:
> 
> [snip]
> 
> > > Problem:
> > >
> > > For months I constantly get random Permission Denied errors on the
> > > client side. Just trying the read again can fix the problem. The
> > > client
> > > will usually show this in dmesg as the same time:
> > > > nfsv4 client/server protocol prob err=10020
> > >
> > This error means "no file handle" and I believe it will happen when
> > the client tries to access the root of the exported tree. (The root
> > specified by the "V4: ..." line in /etc/exports.)
> 
> Isn't it the problem with mountd cleaning all exports and re-exporting
> new list
> on every mount(2) call?
> 
Yes, good point. Doing mounts or sending HUP to mountd could certainly
cause this. (Back when I used a FreeBSD system as a production NFS server,
I never did mounts on it or changed the /etc/exports, I just configured it
and let it run for mounts/years, so I tend to forget this issue.;-)

If this is the cause and you have a recent enough system to support it,
you can try the "-S" option on mountd. Alternately, this issue can be
avoided by switching from mountd to nfse (found on sourceforge).

rick

> 
> --
> Sincerely,
> D.Marck [DM5020, MCK-RIPE, DM3-RIPN]
> [ FreeBSD committer: marck at FreeBSD.org ]
> ------------------------------------------------------------------------
> *** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck at rinet.ru
> ***
> ------------------------------------------------------------------------


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