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Date:   Thu, 1 Oct 2020 16:51:19 -0400
From:   Bruce Fields <bfields@fieldses.org>
To:     Dai Ngo <dai.ngo@oracle.com>
Cc:     linux-nfs@vger.kernel.org
Subject: Re: [PATCH 0/1] NFSv4.2: Fix NFS4ERR_STALE with inter server copy
Message-ID: <20201001205119.GI1496@fieldses.org>
References: <20200923230606.63904-1-dai.ngo@oracle.com>
 <e7e738c6-f6e7-0d04-07fa-8017da469b8a@oracle.com>
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On Tue, Sep 29, 2020 at 08:18:54PM -0700, Dai Ngo wrote:
> Have you had chance to review this patch and if it's ok would it be
> possible to include it in the 5.10 pull?

I don't think the op table approach would be that difficult, I'd really
rather see that.

Is this causing someone an immediate practical problem?

--b.

> 
> Thanks,
> 
> -Dai
> 
> On 9/23/20 4:06 PM, Dai Ngo wrote:
> >This patch provides a temporarily relief for inter copy to work with
> >some common configs.  For long term solution, I think Trond's suggestion
> >of using fs/nfs/nfs_common to store an op table that server can use to
> >access the client code is the way to go.
> >
> >  fs/nfsd/Kconfig | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> >
> >Below are the results of my testing of upstream mainline without and with the fix.
> >
> >Upstream version used for testing:  5.9-rc5
> >
> >1. Upstream mainline (existing code: NFS_FS=y)
> >
> >
> >|----------------------------------------------------------------------------------------|
> >|  NFSD  |  NFS_FS  |  NFS_V4  |               RESULTS                                   |
> >|----------------------------------------------------------------------------------------|
> >|   y    |    y     |    m     | Build errors: nfs42_ssc_open/close                      |
> >|----------------------------------------------------------------------------------------|
> >|   y    |    m     |    m     | Build OK, inter server copy failed with NFS4ERR_STALE   |
> >|        |          |          | See NOTE1.                                              |
> >|----------------------------------------------------------------------------------------|
> >|   y    |    m     |   y (m)  | Build OK, inter server copy failed with NFS4ERR_STALE   |
> >|        |          |          | See NOTE2.                                              |
> >|----------------------------------------------------------------------------------------|
> >|   y    |    y     |    y     | Build OK, inter server copy OK                          |
> >|----------------------------------------------------------------------------------------|
> >
> >
> >|----------------------------------------------------------------------------------------|
> >|  NFSD  |  NFS_FS  |  NFS_V4  |               RESULTS                                   |
> >|----------------------------------------------------------------------------------------|
> >|   m    |    y     |    m     | Build OK, inter server copy OK                          |
> >|----------------------------------------------------------------------------------------|
> >|   m    |    m     |    m     | Build OK, inter server copy failed with NFS4ERR_STALE   |
> >|----------------------------------------------------------------------------------------|
> >|   m    |    m     |   y (m)  | Build OK, inter server copy failed with NFS4ERR_STALE   |
> >|----------------------------------------------------------------------------------------|
> >|   m    |    y     |    y     | Build OK, inter server copy OK                          |
> >|----------------------------------------------------------------------------------------|
> >
> >2. Upstream mainline (with the fix:  !(NFSD=y && (NFS_FS=m || NFS_V4=m))
> >
> >
> >|----------------------------------------------------------------------------------------|
> >|  NFSD  |  NFS_FS  |  NFS_V4  |               RESULTS                                   |
> >|----------------------------------------------------------------------------------------|
> >|   m    |    y     |    m     | Build OK, inter server copy OK                          |
> >|----------------------------------------------------------------------------------------|
> >|   m    |    m     |    m     | Build OK, inter server copy OK                          |
> >|----------------------------------------------------------------------------------------|
> >|   m    |    m     |   y (m)  | Build OK, inter server copy OK                          |
> >|----------------------------------------------------------------------------------------|
> >|   m    |    y     |    y     | Build OK, inter server copy OK                          |
> >|----------------------------------------------------------------------------------------|
> >
> >
> >|----------------------------------------------------------------------------------------|
> >|  NFSD  |  NFS_FS  |  NFS_V4  |               RESULTS                                   |
> >|----------------------------------------------------------------------------------------|
> >|   y    |    y     |    m     | Build OK, inter server copy failed with NFS4ERR_STALE   |
> >|----------------------------------------------------------------------------------------|
> >|   y    |    m     |    m     | Build OK, inter server copy failed with NFS4ERR_STALE   |
> >|----------------------------------------------------------------------------------------|
> >|   y    |    m     |   y (m)  | Build OK, inter server copy failed with NFS4ERR_STALE   |
> >|----------------------------------------------------------------------------------------|
> >|   y    |    y     |    y     | Build OK, inter server copy OK                          |
> >|----------------------------------------------------------------------------------------|
> >
> >NOTE1:
> >BUG:  When inter server copy fails with NFS4ERR_STALE, it left the file
> >created with size of 0!
> >
> >NOTE2:
> >When NFS_V4=y and NFS_FS=m, the build process automatically builds with NFS_V4=m
> >and ignores the setting NFS_V4=y in the config file.
> >
> >This probably due to NFS_V4 in fs/nfs/Kconfig is configured to depend on NFS_FS.
> >