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 III <chuck.lever@oracle.com>
To:     "trondmy@kernel.org" <trondmy@kernel.org>
CC:     Bruce Fields <bfields@redhat.com>,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH 1/2] nfsd4: Handle the NFSv4 READDIR 'dircount' hint being
 zero
Thread-Topic: [PATCH 1/2] nfsd4: Handle the NFSv4 READDIR 'dircount' hint
 being zero
Thread-Index: AQHXtjOgMzi2Ujlpq0WjAUuBQEBhX6u+TkGA
Date:   Fri, 1 Oct 2021 15:59:36 +0000
Message-ID: <C079F240-64D2-4967-BCD2-4A6C425A78DA@oracle.com>
References: <20210930194442.249907-1-trondmy@kernel.org>
In-Reply-To: <20210930194442.249907-1-trondmy@kernel.org>
Accept-Language: en-US
Content-Language: en-US
x-ms-exchange-antispam-messagedata-chunkcount: 1
x-ms-exchange-antispam-messagedata-0: =?us-ascii?Q?x4r2ds5JDTtCnOsysaiu0hTFlyeRziowxt7TKkKicRB6yvCHy0dBHyzTghCV?=
 =?us-ascii?Q?1RrQpL0zcMGGJut+ptsXFIxBubT1sUv9qCOlPjL9B43zEkTGq38USn9EXHjx?=
 =?us-ascii?Q?pwtyoAQ4bdGuriT8U1sBY3lEybNU5ktueODLidlb3ZUicHeFCegwM75a5dmr?=
 =?us-ascii?Q?CBLS68OeIGRwHEYx33/1+fAJMNhQjTUfjRk8K3VIkLKEZtW2GPakAroyEzjb?=
 =?us-ascii?Q?10mn4dkXNnNzqnaLQGazEahNQe0lOelXeuJHZjdnlzIqIhZogP2BwkKFDyOp?=
 =?us-ascii?Q?hYGdSaz3dQxaGrUu6I+JSiOXfrn76rK59FpGGjl9XJoNeNSDyfhOy2z6fqzb?=
 =?us-ascii?Q?XKpQ78UU4ffizRLKJ9nRVlAR9bqGCmA8X1avmyh2uVyirZiaVfv2GaR1JKrL?=
 =?us-ascii?Q?D8Chf/AF6Ns4ffZaOYg8h6H8ap+AUn4Q8wox3yanPIY3ln1j9VVKjAeMZGgW?=
 =?us-ascii?Q?Fhs5okuNNGoaPbBSZ1dLGpTDsqh2NKl8HvXEZseGQ0tpZDA9cyJ02gLeqb1v?=
 =?us-ascii?Q?6Ib+lcaQ9Y/oTjWWEjvlSxGofCz2T4Gq52lv2NkPVAsNbQ9rpogoVV1fScU5?=
 =?us-ascii?Q?kq6F6FXRiQah+HOkRPs0B8AdYFHkb/1gLhtnI5LFQX2yjhBKi/EoaMc8b3C/?=
 =?us-ascii?Q?xfxuy9lXT0Z77Rl4zM4keswjzLkMhAHUVAR13EWZBPA1iDlvmS/FXZd7ImTg?=
 =?us-ascii?Q?c4QX01PZbfiWvzmFD3W9wTWSsTSYhtt36+jxh+NH22HKcgTvhwZE1xuOhtJ0?=
 =?us-ascii?Q?mtSwUd3c2dESnwrSLtUJEEaiakWolzuUR2JMwtksww7aIWl+9wK37mjZzzoV?=
 =?us-ascii?Q?WdihseKtR4HM+djc+7kAVBWvXBMep7YTMokAVu0s3kNA8Fu0+UCXJBFw3Goi?=
 =?us-ascii?Q?GaieR6BONt9afzBmwYa30HINyBwDrKjIoVsmyTXLcP9yifzIb1rZpj69Sgln?=
 =?us-ascii?Q?swd+KssAlsst5oSb8YAAygUKamnxl/3FXWYK1UxyKV94nRxfWnVQ1v9Gy1Sp?=
 =?us-ascii?Q?j7QGhY8Dld6xPxHhZ/GMoY9H27yY+toOTl/dtwAW4adloAafVW1M3PJAQ/Nr?=
 =?us-ascii?Q?wI4xSfQwBk6lyYKhiT+aIGXwj0tjZ6ySTiqGmXvYQar5Nom5iSGQ9/TZUOYF?=
 =?us-ascii?Q?YqNjOs3STW77Iq+vKMFDHHwQtUs/MTiYCF0n6WfzdHGJ5a1owHZJqmp0CJAU?=
 =?us-ascii?Q?fWhidGEGUwi4/yORv6xJJ9sn4zE9T0bsOJOt8O8P6bgffhvLWEvnU97PqHi0?=
 =?us-ascii?Q?f6WCSpeC/7sphd7mRQj09+qV7igwmSpUDV4dJbU1adOK6X3yLlFXunlzwnLr?=
 =?us-ascii?Q?B0eLb0NmMw776d7TV44frjGM?=
x-ms-exchange-transport-forked: True
Content-Type: text/plain; charset="us-ascii"
Content-ID: <6B6ED5ED6108BB45AD3B8D2F8D140482@namprd10.prod.outlook.com>
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-OriginatorOrg: oracle.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-AuthSource: SJ0PR10MB4688.namprd10.prod.outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 4ce9edab-670e-4783-4145-08d984f47819
X-MS-Exchange-CrossTenant-originalarrivaltime: 01 Oct 2021 15:59:36.9930
 (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: RjMSGC5eg4453D/kSQ+Y76IGXPIa5XiFXfGfGAPahmB10xu+L3b1Y2YNMjd3BodKfLb9cGFpkFZ5GsMmtAb9Sw==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ0PR10MB4496
X-Proofpoint-Virus-Version: vendor=nai engine=6300 definitions=10124 signatures=668683
X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxlogscore=999 suspectscore=0
 mlxscore=0 spamscore=0 adultscore=0 bulkscore=0 phishscore=0
 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1
 engine=8.12.0-2109230001 definitions=main-2110010111
X-Proofpoint-GUID: tGAyY6Odx9-9se3TOTScMEvrXVI661Aa
X-Proofpoint-ORIG-GUID: tGAyY6Odx9-9se3TOTScMEvrXVI661Aa
Precedence: bulk
List-ID: <linux-nfs.vger.kernel.org>
X-Mailing-List: linux-nfs@vger.kernel.org


> On Sep 30, 2021, at 3:44 PM, trondmy@kernel.org wrote:
>=20
> From: Trond Myklebust <trond.myklebust@hammerspace.com>
>=20
> RFC3530 notes that the 'dircount' field may be zero, in which case the
> recommendation is to ignore it, and only enforce the 'maxcount' field.
> In RFC5661, this recommendation to ignore a zero valued field becomes a
> requirement.
>=20
> Fixes: aee377644146 ("nfsd4: fix rd_dircount enforcement")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Pulled into the next 5.15-rc for NFSD. Thanks!


> ---
> fs/nfsd/nfs4xdr.c | 19 +++++++++++--------
> 1 file changed, 11 insertions(+), 8 deletions(-)
>=20
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index 7abeccb975b2..cf030ebe2827 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -3544,15 +3544,18 @@ nfsd4_encode_dirent(void *ccdv, const char *name,=
 int namlen,
> 		goto fail;
> 	cd->rd_maxcount -=3D entry_bytes;
> 	/*
> -	 * RFC 3530 14.2.24 describes rd_dircount as only a "hint", so
> -	 * let's always let through the first entry, at least:
> +	 * RFC 3530 14.2.24 describes rd_dircount as only a "hint", and
> +	 * notes that it could be zero. If it is zero, then the server
> +	 * should enforce only the rd_maxcount value.
> 	 */
> -	if (!cd->rd_dircount)
> -		goto fail;
> -	name_and_cookie =3D 4 + 4 * XDR_QUADLEN(namlen) + 8;
> -	if (name_and_cookie > cd->rd_dircount && cd->cookie_offset)
> -		goto fail;
> -	cd->rd_dircount -=3D min(cd->rd_dircount, name_and_cookie);
> +	if (cd->rd_dircount) {
> +		name_and_cookie =3D 4 + 4 * XDR_QUADLEN(namlen) + 8;
> +		if (name_and_cookie > cd->rd_dircount && cd->cookie_offset)
> +			goto fail;
> +		cd->rd_dircount -=3D min(cd->rd_dircount, name_and_cookie);
> +		if (!cd->rd_dircount)
> +			cd->rd_maxcount =3D 0;
> +	}
>=20
> 	cd->cookie_offset =3D cookie_offset;
> skip_entry:
> --=20
> 2.31.1
>=20

--
Chuck Lever