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From:   Chuck Lever III <chuck.lever@oracle.com>
To:     Dai Ngo <dai.ngo@oracle.com>
CC:     Bruce Fields <bfields@fieldses.org>,
        Jeff Layton <jlayton@redhat.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
        "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH RFC v16 04/11] NFSD: Update nfsd_breaker_owns_lease() to
 handle courtesy clients
Thread-Topic: [PATCH RFC v16 04/11] NFSD: Update nfsd_breaker_owns_lease() to
 handle courtesy clients
Thread-Index: AQHYNbbOt4lEkyAZMUuWU1WhGW7wyay9fJKA
Date:   Sun, 13 Mar 2022 16:04:21 +0000
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 <1647051215-2873-5-git-send-email-dai.ngo@oracle.com>
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> On Mar 11, 2022, at 9:13 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>=20
> Update nfsd_breaker_owns_lease() to handle delegation conflict
> with courtesy clients. If conflict was caused by courtesy client
> then discard the courtesy client by setting CLIENT_EXPIRED and
> return conflict resolved. Client with CLIENT_EXPIRED is expired
> by the laundromat.
>=20
> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
> ---
> fs/nfsd/nfs4state.c | 26 ++++++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>=20
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 583ac807e98d..2beb0972de88 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -4713,6 +4713,28 @@ nfsd_break_deleg_cb(struct file_lock *fl)
> 	return ret;
> }
>=20
> +static bool
> +nfs4_check_and_expire_courtesy_client(struct nfs4_client *clp)
> +{
> +	/*
> +	 * need to sync with courtesy client trying to reconnect using
> +	 * the cl_cs_lock, nn->client_lock can not be used since this
> +	 * function is called with the fl_lck held.
> +	 */
> +	spin_lock(&clp->cl_cs_lock);
> +	if (test_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags)) {
> +		spin_unlock(&clp->cl_cs_lock);
> +		return true;
> +	}
> +	if (test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags)) {
> +		set_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags);
> +		spin_unlock(&clp->cl_cs_lock);
> +		return true;
> +	}
> +	spin_unlock(&clp->cl_cs_lock);
> +	return false;
> +}
> +
> /**
>  * nfsd_breaker_owns_lease - Check if lease conflict was resolved
>  * @fl: Lock state to check
> @@ -4727,6 +4749,10 @@ static bool nfsd_breaker_owns_lease(struct file_lo=
ck *fl)
> 	struct svc_rqst *rqst;
> 	struct nfs4_client *clp;
>=20
> +	clp =3D dl->dl_stid.sc_client;
> +	if (nfs4_check_and_expire_courtesy_client(clp))

Since you'll need to fix the kernel robot issue in 1/11, when you
repost, can you also just pass dl->dl_stid.sc_client directly to
nfs4_check_and_expire_courtesy_client() here?


> +		return true;
> +
> 	if (!i_am_nfsd())
> 		return false;
> 	rqst =3D kthread_data(current);
> --=20
> 2.9.5
>=20

--
Chuck Lever