Received-SPF: pass (google.com: domain of linux-nfs-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Chuck Lever <chuck.lever@oracle.com>
To:     Bruce Fields <bfields@fieldses.org>
CC:     Linux NFS Mailing List <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH] nfsd: register pernet ops last, unregister first
Thread-Topic: [PATCH] nfsd: register pernet ops last, unregister first
Thread-Index: AQHW+kuPqXx9ogEBD06qHoGJB6Hv2apGo34A
Date:   Wed, 3 Feb 2021 16:45:56 +0000
Message-ID: <70729484-C3C8-477F-8FE3-06B6A70510C6@oracle.com>
References: <20210203164213.GA26588@fieldses.org>
In-Reply-To: <20210203164213.GA26588@fieldses.org>
Accept-Language: en-US
Content-Language: en-US
Content-Type: text/plain; charset="us-ascii"
Content-ID: <3854ABCC37CEDC4CBE6736AB0ED62C9B@namprd10.prod.outlook.com>
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: f0b10231-9085-4bab-29b2-08d8c8632dad
X-MS-Exchange-CrossTenant-originalarrivaltime: 03 Feb 2021 16:45:56.5301
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: Dt63zgI/szp1EYB/kw7r56SL5HGHLSREixEAF1/lnNChj2ilg5IEckfL+spn6VCg08jc1d2y3tArJ4cMI5O2yQ==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ0PR10MB4687
X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=9884 signatures=668683
X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 mlxlogscore=999 phishscore=0
 spamscore=0 suspectscore=0 malwarescore=0 adultscore=0 bulkscore=0
 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000
 definitions=main-2102030100
X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=9884 signatures=668683
X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 mlxlogscore=999
 mlxscore=0 priorityscore=1501 spamscore=0 impostorscore=0 clxscore=1015
 suspectscore=0 lowpriorityscore=0 phishscore=0 adultscore=0 bulkscore=0
 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000
 definitions=main-2102030100
Precedence: bulk
List-ID: <linux-nfs.vger.kernel.org>
X-Mailing-List: linux-nfs@vger.kernel.org

Hi Bruce-


> On Feb 3, 2021, at 11:42 AM, J. Bruce Fields <bfields@fieldses.org> wrote=
:
>=20
> From: "J. Bruce Fields" <bfields@redhat.com>
>=20
> These pernet operations may depend on stuff set up or torn down in the
> module init/exit functions.  And they may be called at any time in
> between.  So it makes more sense for them to be the last to be
> registered in the init function, and the first to be unregistered in the
> exit function.
>=20
> In particular, without this, the drc slab is being destroyed before all
> the per-net drcs are shut down, resulting in an "Objects remaining in
> nfsd_drc on __kmem_cache_shutdown()" warning in exit_nfsd.
>=20
> Reported-by: Zhi Li <yieli@redhat.com>
> Fixes: 3ba75830ce17 "nfsd4: drc containerization"
> Signed-off-by: J. Bruce Fields <bfields@redhat.com>

I can't tell how urgent this is. Does it belong in 5.11-rc?


> ---
> fs/nfsd/nfsctl.c | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>=20
> diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
> index f6d5d783f4a4..0759e589ab52 100644
> --- a/fs/nfsd/nfsctl.c
> +++ b/fs/nfsd/nfsctl.c
> @@ -1522,12 +1522,9 @@ static int __init init_nfsd(void)
> 	int retval;
> 	printk(KERN_INFO "Installing knfsd (copyright (C) 1996 okir@monad.swb.de=
).\n");
>=20
> -	retval =3D register_pernet_subsys(&nfsd_net_ops);
> -	if (retval < 0)
> -		return retval;
> 	retval =3D register_cld_notifier();
> 	if (retval)
> -		goto out_unregister_pernet;
> +		return retval;
> 	retval =3D nfsd4_init_slabs();
> 	if (retval)
> 		goto out_unregister_notifier;
> @@ -1544,9 +1541,14 @@ static int __init init_nfsd(void)
> 		goto out_free_lockd;
> 	retval =3D register_filesystem(&nfsd_fs_type);
> 	if (retval)
> +		goto out_free_exports;
> +	retval =3D register_pernet_subsys(&nfsd_net_ops);
> +	if (retval < 0)
> 		goto out_free_all;
> 	return 0;
> out_free_all:
> +	unregister_pernet_subsys(&nfsd_net_ops);
> +out_free_exports:
> 	remove_proc_entry("fs/nfs/exports", NULL);
> 	remove_proc_entry("fs/nfs", NULL);
> out_free_lockd:
> @@ -1559,13 +1561,12 @@ static int __init init_nfsd(void)
> 	nfsd4_free_slabs();
> out_unregister_notifier:
> 	unregister_cld_notifier();
> -out_unregister_pernet:
> -	unregister_pernet_subsys(&nfsd_net_ops);
> 	return retval;
> }
>=20
> static void __exit exit_nfsd(void)
> {
> +	unregister_pernet_subsys(&nfsd_net_ops);
> 	nfsd_drc_slab_free();
> 	remove_proc_entry("fs/nfs/exports", NULL);
> 	remove_proc_entry("fs/nfs", NULL);
> @@ -1575,7 +1576,6 @@ static void __exit exit_nfsd(void)
> 	nfsd4_exit_pnfs();
> 	unregister_filesystem(&nfsd_fs_type);
> 	unregister_cld_notifier();
> -	unregister_pernet_subsys(&nfsd_net_ops);
> }
>=20
> MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");
> --=20
> 2.29.2
>=20

--
Chuck Lever