Re: [PATCH v4 1/1] NFSv4.2: Fix NFS4ERR_STALE error when doing inter server copy

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

On Mon, Nov 09, 2020 at 11:34:08AM -0800, Dai Ngo wrote:
> 
> On 11/9/20 10:30 AM, J. Bruce Fields wrote:
> >On Tue, Oct 20, 2020 at 11:34:35AM -0700, Dai Ngo wrote:
> >>On 10/20/20 10:01 AM, J. Bruce Fields wrote:
> >>>On Sun, Oct 18, 2020 at 11:42:49PM -0400, Dai Ngo wrote:
> >>>>NFS_FS=y as dependency of CONFIG_NFSD_V4_2_INTER_SSC still have
> >>>>build errors and some configs with NFSD=m to get NFS4ERR_STALE
> >>>>error when doing inter server copy.
> >>>>
> >>>>Added ops table in nfs_common for knfsd to access NFS client modules.
> >>>OK, looks reasonable to me, applying.  Does this resolve all the
> >>>problems you've seen, or is there any bad case left?
> >>Thanks Bruce.
> >>
> >>With this patch, I no longer see the NFS4ERR_STALE in any config.
> >>
> >>The problem with NFS4ERR_STALE was because of a bug in nfs42_ssc_open.
> >>When CONFIG_NFSD_V4_2_INTER_SSC is not defined, nfs42_ssc_open
> >>returns NULL which is incorrect allowing the operation to continue
> >>until nfsd4_putfh which does not have the code to handle nfserr_stale.
> >>
> >>With this patch, when CONFIG_NFSD_V4_2_INTER_SSC is not defined the
> >>new nfs42_ssc_open returns ERR_PTR(-EIO) which causes the NFS client
> >>to switch over to the split copying (read src and write to dst).
> >That sounds reasonable, but I don't see any of the patches you've sent
> >changing that error return.  Did I overlook something, or did you mean
> >to append a patch to this message?
> 
> Since with the patch, I did not run into the condition where NFS4ERR_STALE
> is returned so I did not fix this return error code. Do you want me to
> submit another patch to change the returned error code from NFS4ERR_STALE
> to NFS4ERR_NOTSUPP if it ever runs into that condition?

That would be great, thanks.  (I mean, it is still possible to hit that
case, right?  You just didn't test with !CONFIG_NFSD_V4_2_INTER_SSC ?)

--b.