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Date:   Fri, 30 Aug 2019 13:56:08 -0400
To:     Olga Kornievskaia <olga.kornievskaia@gmail.com>
Cc:     "J. Bruce Fields" <bfields@redhat.com>,
        linux-nfs <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH v5 5/9] NFSD add COPY_NOTIFY operation
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From:   bfields@fieldses.org (J. Bruce Fields)
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On Thu, Aug 29, 2019 at 03:23:43PM -0400, Olga Kornievskaia wrote:
> I'm stuck again. The idea that Trond gave me is to instead of storing
> the pointer to the stateid, (copy) store the stateid_t structure
> itself and then use it to look it up the appropriate nfs4_stid.
> 
> The problem with that is when nfsd4_lookup_stateid() is called it
> takes is a compound state (cstate) which has a client pointer and
> during the lookup it's verified that the client looking up the stateid
> is the same that generate the stateid which is not the case with copy
> offload.
> 
> I tried also saving a cl_clientid and using that to lookup the
> nfs4_client that's needed for the stateid lookup but I'm not sure
> that's possible. lookup_clientid() calls find_client_in_id_table() and
> always passes "false" for sessions args. Original client has minor
> version 2 and then the check if (clp->minor_versions != sessions)
> fails. I don't understand what this logic is suppose to check.
> 
> Should I be writing special version of the lookup_clientid that
> ignores that check (when called in the path of the copy_notify
> verification)? Or any other ideas of how to get passed this would be
> appreciated it.

Yeah, I think you may want to do the clientid lookup by hand under
cl_lock, and take the cl_ref?

Or turn things around and ensure that copy stateid's are destroyed
before clients are.

--b.