linux-kernel - Re: [PATCH] NFSv4: nfs4_do_fsinfo() should not do implicit lease renewals

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Date:   Mon, 16 Dec 2019 18:24:39 +0000
From:   Trond Myklebust <trondmy@...merspace.com>
To:     "linux-nfs@...r.kernel.org" <linux-nfs@...r.kernel.org>,
        "rmilkowski@...il.com" <rmilkowski@...il.com>
CC:     "anna.schumaker@...app.com" <anna.schumaker@...app.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] NFSv4: nfs4_do_fsinfo() should not do implicit lease
 renewals

On Mon, 2019-12-16 at 17:38 +0000, Robert Milkowski wrote:
> From: Robert Milkowski <rmilkowski@...il.com>
> 
> Currently, each time nfs4_do_fsinfo() is called it will do an
> implicit
> NFS4 lease renewal, which is not compliant with the NFS4
> specification.
> This can result in a lease being expired by NFS server which will
> then
> return NFS4ERR_EXPIRED or NFS4ERR_STALE_CLIENTID.
> 
> Signed-off-by: Robert Milkowski <rmilkowski@...il.com>
> ---
>  fs/nfs/nfs4proc.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index 76d3716..aad65dd 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -5019,16 +5019,19 @@ static int nfs4_do_fsinfo(struct nfs_server
> *server,
> struct nfs_fh *fhandle, str
>  	struct nfs4_exception exception = {
>  		.interruptible = true,
>  	};
> -	unsigned long now = jiffies;
> +	unsigned long last_renewal = jiffies;
>  	int err;
>  
>  	do {
>  		err = _nfs4_do_fsinfo(server, fhandle, fsinfo);
>  		trace_nfs4_fsinfo(server, fhandle, fsinfo->fattr, err);
>  		if (err == 0) {
> +			/* no implicit lease renewal allowed here */
> +			if (server->nfs_client->cl_last_renewal != 0)
> +				last_renewal =
> server->nfs_client->cl_last_renewal;
>  			nfs4_set_lease_period(server->nfs_client,
>  					fsinfo->lease_time * HZ,
> -					now);
> +					last_renewal);
>  			break;
>  		}
>  		err = nfs4_handle_exception(server, err, &exception);

NACK. The above argument only applies to legacy minor version 0 setups,
and does not apply to NFSv4.1 or newer.

-- 
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@...merspace.com