On Wed, 2012-08-08 at 13:51 -0400, Fred Isaman wrote:
> On Wed, Aug 8, 2012 at 1:34 PM, Myklebust, Trond
> <Trond.Myklebust@xxxxxxxxxx> wrote:
> > On Wed, 2012-08-08 at 18:48 +0200, Tigran Mkrtchyan wrote:
> >> Hi,
> >>
> >> It's quite some time without kernel panic reports from me ....
> >>
> >> Observer on MDS and DS shutdown during IO.
> >>
> >> This is with 3.5.0-2.fc17.x86_64 kernel. Line in code:
> >>
> >> nfs4proc.c:6252 : BUG_ON(!list_empty(&lo->plh_segs));
> >>
> >
> > If the server doesn't return a stateid, then that is supposed to
> > indicate that it thinks that it doesn't hold any more layout segments
> > for this file.
> > To me, that indicates that we should be calling
> > mark_matching_lsegs_invalid() rather than Oopsing.
> >
> > Any dissenting voices from the pNFS crowd?
> >
>
> But this implies that the client thinks it has a layout which the
> server does not believe it has, which seems to me to imply an earlier
> bug. If you change to mark_matching_lsegs_invalid, I would suggest
> keeping a WARN_ON.
We could possibly add a printk, but I don't see what value a WARN_ON
would have here: how is a stack dump going to be useful in debugging
this issue?
Also, don't we sometimes expect this sort of thing to happen on
occasion? What if our layoutreturn ends up racing with the layout recall
following a DS shutdown?
--
Trond Myklebust
Linux NFS client maintainer
NetApp
Trond.Myklebust@xxxxxxxxxx
www.netapp.com
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