On Wed, 2013-09-11 at 08:59 -0400, Anna Schumaker wrote:
> Do we need to do a get_rpccred() after looking up the machine cred in
> nfs_alloc_client()? Where does our guaranteed reference come from?
See my comment to Dros' first patchset yesterday. In the case of
SP4_MACH_CRED, we cannot change the machine credential, since the state
protection is completely tied to that credential. In fact if you look at
the current code, we only actually free the cl_machine_cred in
nfs_free_client().
For that reason, it is safe to assume that it is available for the
duration of the RPC call. Of course, rpc_task_set_rpc_message() will
also take a reference, but that too is redundant in this particular
case.
Cheers
Trond
> Anna
>
>
>
> On Tue, Sep 10, 2013 at 6:44 PM, Weston Andros Adamson
> <dros@xxxxxxxxxx> wrote:
> The cl_machine_cred doesn't need to be reference counted here
> -
> a reference is held is for the lifetime of the struct
> nfs_client.
> Also, no need to put_rpccred the rpc_message.rpc_cred.
>
> Signed-off-by: Weston Andros Adamson <dros@xxxxxxxxxx>
> ---
> fs/nfs/nfs4_fs.h | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
> index f520a11..07a8aa9 100644
> --- a/fs/nfs/nfs4_fs.h
> +++ b/fs/nfs/nfs4_fs.h
> @@ -279,10 +279,10 @@ _nfs4_state_protect(struct nfs_client
> *clp, unsigned long sp4_mode,
> if (test_bit(sp4_mode, &clp->cl_sp4_flags)) {
> spin_lock(&clp->cl_lock);
> if (clp->cl_machine_cred != NULL)
> - newcred =
> get_rpccred(clp->cl_machine_cred);
> + /* don't call get_rpccred on the
> machine cred -
> + * a reference will be held for life
> of clp */
> + newcred = clp->cl_machine_cred;
> spin_unlock(&clp->cl_lock);
> - if (msg->rpc_cred)
> - put_rpccred(msg->rpc_cred);
> msg->rpc_cred = newcred;
>
> flavor =
> clp->cl_rpcclient->cl_auth->au_flavor;
> --
> 1.7.12.4 (Apple Git-37)
>
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>
--
Trond Myklebust
Linux NFS client maintainer
NetApp
Trond.Myklebust@xxxxxxxxxx
www.netapp.com
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