Re: [3.2.5] Stale NFS file handle issue on subdirectory of NFSv3 mount

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

On Wed, Feb 29, 2012 at 11:59:16AM -0800, Simon Kirby wrote:
> On Wed, Feb 29, 2012 at 01:11:31AM +0000, Myklebust, Trond wrote:
> 
> > On Tue, 2012-02-28 at 17:06 -0800, Simon Kirby wrote:
> > > Hi,
> > > 
> > > Since upgrading from 2.6.39-ish to 3.1-ish, and on 3.2.5, we are seeing a
> > > lot of occurrences of Stale NFS file handle errors when accessing a mount
> > > whose NFSv3 source is a subdirectory of another mount point. For example,
> > > in this case:
> > > 
> > > # mount | grep /shared
> > > 10.10.1.1:/storage/vg1/shared on /shared type nfs (rw,hard,intr,tcp,timeo=300,retrans=2,vers=3,addr=10.10.1.1)
> > > 10.10.1.1:/storage/vg1/shared/fp on /usr/local/fp type nfs (rw,hard,intr,tcp,timeo=300,retrans=2,vers=3,addr=10.10.1.1)
> > > 
> > > When the issue occurs, the /shared mount point is fine as is /shared/fp,
> > > but "df" or "ls" or anything on /usr/local/fp will ESTALE. This somehow
> > > corrected itself while I was trying to gather information this time, but
> > > usually the d_ino returned by getdents() on the parent directory shows a
> > > different inode number than for /shared/fp.
> > > 
> > > When this happens, I am unable to umount -f or umount -l /usr/local/fp
> > > (ESTALE), but I can actually umount /shared; umount /usr/local/fp; and
> > > mount -a, which seems to "fix" it.
> > > 
> > > is this acting similar to a bind mount internally now and revalidation or
> > > something is breaking in this case? This is happening fairly often, so I
> > > will try to collect more info again next time.
> > 
> > ESTALE is a server side error, not a client side error. What server are
> > you using here, and what do the export options look like?
> 
> An older 2.6.33 host running DRBD HA knfsd bits. We had problems with the
> XFS inode reclaim changes causing crashes on newer kernels (actually on
> 2.6.33, too, but not so much on this node with only locally-attached
> disks), so these kernels haven't been upgraded for some time. It's likely
> time to try again. The export is:
> 
> /storage/vg1 /10.10.1.0/24(rw,sync,no_root_squash,no_subtree_check,fsid=1)
> 
> I just found it weird to see the ESTALE when accessing /usr/local/fp,
> while /shared/fp works fine at the same time, even though they're the
> same path on the server.

Is /storage/vg1/shared/fp on that server something that can ever be
removed?  (Say to be replaced by something else?)

For normal directories that's not a problem, the client's used to
dealing with the fact that directories may come and go.

For a directory that you've told the client to *mount*, that's dirty
trick--it's really expecting that directory to be there as long as it's 
mounted....

--b.

> 
> The plan was to upgrade this pair first anyway, so we can do that if
> the problem is likely coming from the server side.
> 
> Simon-
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