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Date:   Thu, 26 Nov 2020 18:17:41 +0100 (CET)
From:   "Mkrtchyan, Tigran" <tigran.mkrtchyan@desy.de>
To:     trondmy <trondmy@hammerspace.com>
Cc:     linux-nfs <linux-nfs@vger.kernel.org>,
        Anna Schumaker <anna.schumaker@netapp.com>
Message-ID: <1350578257.196601.1606411061845.JavaMail.zimbra@desy.de>
In-Reply-To: <1959492891.1289318.1605624657755.JavaMail.zimbra@desy.de>
References: <20201110231906.863446-1-trondmy@kernel.org> <1375056959.614278.1605271687151.JavaMail.zimbra@desy.de> <994125760.684644.1605303041944.JavaMail.zimbra@desy.de> <d73c15ca631ad52f036bb8708ab15b89af432952.camel@hammerspace.com> <1371149886.691555.1605311212511.JavaMail.zimbra@desy.de> <fc82f441b9393720102f1a7e151517ef881f99df.camel@hammerspace.com> <291795931.1083930.1605560150768.JavaMail.zimbra@desy.de> <1959492891.1289318.1605624657755.JavaMail.zimbra@desy.de>
Subject: Re: [PATCH v3 00/11] Add RDMA support to the pNFS file+flexfiles
 data channels
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Thread-Topic: Add RDMA support to the pNFS file+flexfiles data channels
Thread-Index: AQHWt7lTY9xR7iW33kG2X9IO1/hKs6nCBtsAFTVACHJOhL5PDfzm1vaA/xWRAGqA63bEgH5VnYYpbZFtEolbqobiQw==
Precedence: bulk


I have added some debug info Ind got this:

decode_getdeviceinfo: layout type 4
decode_getdeviceinfo: layout size 64
decode_getdeviceinfo: layout notification bitmap size 1094994757

So it looks like that xdr_read_pages set xdr pointer to a wrong position
and next read, which is bitmap size

5857         pdev->mincount =3D be32_to_cpup(p);
5858         dprintk("%s: layout size %u\n", __func__, pdev->mincount);
5859         if (xdr_read_pages(xdr, pdev->mincount) !=3D pdev->mincount)
5860                 return -EIO;
5861=20
5862         /* Parse notification bitmap, verifying that it is zero. */
5863         p =3D xdr_inline_decode(xdr, 4);
5864         if (unlikely(!p))
5865                 return -EIO;
5866         len =3D be32_to_cpup(p);
5867         dprintk("%s: layout notification bitmap size %u\n", __func__, =
len);
5868         if (len) {
5869                 uint32_t i;


Tigran.


----- Original Message -----
> From: "Tigran Mkrtchyan" <tigran.mkrtchyan@desy.de>
> To: "trondmy" <trondmy@hammerspace.com>
> Cc: "linux-nfs" <linux-nfs@vger.kernel.org>, "Anna Schumaker" <anna.schum=
aker@netapp.com>
> Sent: Tuesday, 17 November, 2020 15:50:57
> Subject: Re: [PATCH v3 00/11] Add RDMA support to the pNFS file+flexfiles=
 data channels

> Here is the result:
>=20
>=20
> $ git bisect bad
> c567552612ece787b178e3b147b5854ad422a836 is the first bad commit
> commit c567552612ece787b178e3b147b5854ad422a836
> Author: Anna Schumaker <Anna.Schumaker@Netapp.com>
> Date:   Wed May 28 13:41:22 2014 -0400
>=20
>    NFS: Add READ_PLUS data segment support
>   =20
>    This patch adds client support for decoding a single NFS4_CONTENT_DATA
>    segment returned by the server. This is the simplest implementation
>    possible, since it does not account for any hole segments in the reply=
.
>   =20
>    Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
>=20
> fs/nfs/nfs42xdr.c         | 141 +++++++++++++++++++++++++++++++++++++++++=
+++++
> fs/nfs/nfs4client.c       |   2 +
> fs/nfs/nfs4proc.c         |  43 +++++++++++++-
> fs/nfs/nfs4xdr.c          |   1 +
> include/linux/nfs4.h      |   2 +-
> include/linux/nfs_fs_sb.h |   1 +
> include/linux/nfs_xdr.h   |   2 +-
> 7 files changed, 187 insertions(+), 5 deletions(-)
>=20
>=20
> Regards,
>   Tigran.
>=20
>=20
>=20
> ----- Original Message -----
>> From: "Tigran Mkrtchyan" <tigran.mkrtchyan@desy.de>
>> To: "trondmy" <trondmy@hammerspace.com>
>> Cc: "linux-nfs" <linux-nfs@vger.kernel.org>
>> Sent: Monday, 16 November, 2020 21:55:50
>> Subject: Re: [PATCH v3 00/11] Add RDMA support to the pNFS file+flexfile=
s data
>> channels
>=20
>> Hi Trond,
>>=20
>> I am afraid, that the fix didn't work. I bisecting it....
>>=20
>>=20
>> Tigran.
>>=20
>>=20
>> ----- Original Message -----
>>> From: "trondmy" <trondmy@hammerspace.com>
>>> To: "Tigran Mkrtchyan" <tigran.mkrtchyan@desy.de>
>>> Cc: "linux-nfs" <linux-nfs@vger.kernel.org>
>>> Sent: Saturday, 14 November, 2020 15:29:01
>>> Subject: Re: [PATCH v3 00/11] Add RDMA support to the pNFS file+flexfil=
es data
>>> channels
>>=20
>>> On Sat, 2020-11-14 at 00:46 +0100, Mkrtchyan, Tigran wrote:
>>>>=20
>>>>=20
>>>> ----- Original Message -----
>>>> > From: "trondmy" <trondmy@hammerspace.com>
>>>> > To: "Tigran Mkrtchyan" <tigran.mkrtchyan@desy.de>
>>>> > Cc: "linux-nfs" <linux-nfs@vger.kernel.org>
>>>> > Sent: Friday, 13 November, 2020 23:45:00
>>>> > Subject: Re: [PATCH v3 00/11] Add RDMA support to the pNFS
>>>> > file+flexfiles data channels
>>>>=20
>>>> > On Fri, 2020-11-13 at 22:30 +0100, Mkrtchyan, Tigran wrote:
>>>> > >=20
>>>> > > After more testing, it looks like that client doesn't like
>>>> > > notification bitmap:
>>>> > >=20
>>>> > >=20
>>>> > > [31576.789492] --> _nfs4_proc_getdeviceinfo
>>>> > > [31576.789503] --> nfs41_call_sync_prepare data->seq_server
>>>> > > 000000001d17c43e
>>>> > > [31576.789507] --> nfs4_alloc_slot used_slots=3D0000
>>>> > > highest_used=3D4294967295 max_slots=3D16
>>>> > > [31576.789510] <-- nfs4_alloc_slot used_slots=3D0001 highest_used=
=3D0
>>>> > > slotid=3D0
>>>> > > [31576.789527] encode_sequence:
>>>> > > sessionid=3D2910695007:150995712:0:16777216 seqid=3D92462 slotid=
=3D0
>>>> > > max_slotid=3D0 cache_this=3D0
>>>> > > [31576.789991] decode_getdeviceinfo: unsupported notification
>>>> >=20
>>>> > According to this, you appear to be returning a deviceinfo bitmap
>>>> > with
>>>> > at least one non-zero entry that is not in the first 32-bit word.
>>>> > We
>>>> > only ask for notifications for NOTIFY_DEVICEID4_CHANGE and
>>>> > NOTIFY_DEVICEID4_DELETE, so we only expect bitmap[0] to have non-
>>>> > zero
>>>> > entries.
>>>>=20
>>>>=20
>>>> according to packet capture only bitmap[0] has non zero bits set.
>>>> This is the reply of compound starting from nfs staus code, tag
>>>> length and so on.
>>>>=20
>>>>=20
>>>> 0000=C2=A0=C2=A0 00 00 00 00 00 00 00 00 00 00 00 02 00 00 00 35
>>>> 0010=C2=A0=C2=A0 00 00 00 00 5f ae 7d ad 00 03 00 09 00 00 00 00
>>>> 0020=C2=A0=C2=A0 00 00 00 01 00 00 00 4c 00 00 00 00 00 00 00 0f
>>>> 0030=C2=A0=C2=A0 00 00 00 0f 00 00 00 00 00 00 00 2f 00 00 00 00
>>>> 0040=C2=A0=C2=A0 00 00 00 04 00 00 00 40 00 00 00 01 00 00 00 03
>>>> 0050=C2=A0=C2=A0 74 63 70 00 00 00 00 16 31 33 31 2e 31 36 39 2e
>>>> 0060=C2=A0=C2=A0 31 39 31 2e 31 34 33 2e 31 32 35 2e 34 39 00 00
>>>> 0070=C2=A0=C2=A0 00 00 00 01 00 00 00 04 00 00 00 01 00 10 00 00
>>>> 0080=C2=A0=C2=A0 00 10 00 00 00 00 00 01 00 00 00 02 00 00 00 06
>>>> 0090=C2=A0=C2=A0 00 00 00 00
>>>>=20
>>>>=20
>>>> the last 12 bytes : bitmap size, bitmap[0], bitmap[1]
>>>>=20
>>>>=20
>>>> This part of code in the didn't change since 2010, and I
>>>> have no issues to use 5.8 kernel. I am pretty sure, that
>>>> tests with 5.9 did pass as expected. I will try to bisec it.
>>>=20
>>> I don't think I've introduced this bug. I did not touch anything in the
>>> getdeviceinfo proc or XDR code.
>>> Does the following patch help?
>>>=20
>>> 8<-------------------------------------------------------
>>> From e92b2d4e39e91d379ec1147115820ab5dfe4c89a Mon Sep 17 00:00:00 2001
>>> From: Trond Myklebust <trond.myklebust@hammerspace.com>
>>> Date: Fri, 13 Nov 2020 21:42:16 -0500
>>> Subject: [PATCH] NFSv4: Fix the alignment of page data in the getdevice=
info
>>> reply
>>>=20
>>> We can fit the device_addr4 opaque data padding in the pages.
>>>=20
>>> Fixes: cf500bac8fd4 ("SUNRPC: Introduce rpc_prepare_reply_pages()")
>>> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
>>> ---
>>> fs/nfs/nfs4xdr.c | 14 ++++++++++----
>>> 1 file changed, 10 insertions(+), 4 deletions(-)
>>>=20
>>> diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
>>> index c6dbfcae7517..c8714381d511 100644
>>> --- a/fs/nfs/nfs4xdr.c
>>> +++ b/fs/nfs/nfs4xdr.c
>>> @@ -3009,15 +3009,19 @@ static void nfs4_xdr_enc_getdeviceinfo(struct r=
pc_rqst
>>> *req,
>>> =09struct compound_hdr hdr =3D {
>>> =09=09.minorversion =3D nfs4_xdr_minorversion(&args->seq_args),
>>> =09};
>>> +=09uint32_t replen;
>>>=20
>>> =09encode_compound_hdr(xdr, req, &hdr);
>>> =09encode_sequence(xdr, &args->seq_args, &hdr);
>>> +
>>> +=09replen =3D hdr.replen + op_decode_hdr_maxsz;
>>> +
>>> =09encode_getdeviceinfo(xdr, args, &hdr);
>>>=20
>>> -=09/* set up reply kvec. Subtract notification bitmap max size (2)
>>> -=09 * so that notification bitmap is put in xdr_buf tail */
>>> +=09/* set up reply kvec. device_addr4 opaque data is read into the
>>> +=09 * pages */
>>> =09rpc_prepare_reply_pages(req, args->pdev->pages, args->pdev->pgbase,
>>> -=09=09=09=09args->pdev->pglen, hdr.replen - 2);
>>> +=09=09=09=09args->pdev->pglen, replen + 2);
>>> =09encode_nops(&hdr);
>>> }
>>>=20
>>> @@ -5848,7 +5852,9 @@ static int decode_getdeviceinfo(struct xdr_stream=
 *xdr,
>>> =09 * and places the remaining xdr data in xdr_buf->tail
>>> =09 */
>>> =09pdev->mincount =3D be32_to_cpup(p);
>>> -=09if (xdr_read_pages(xdr, pdev->mincount) !=3D pdev->mincount)
>>> +=09/* Calculate padding */
>>> +=09len =3D xdr_align_size(pdev->mincount);
>>> +=09if (xdr_read_pages(xdr, len) !=3D len)
>>> =09=09return -EIO;
>>>=20
>>> =09/* Parse notification bitmap, verifying that it is zero. */
>>> --
>>> 2.28.0
>>>=20
>>>=20
>>>=20
>>> --
>>> Trond Myklebust
>>> Linux NFS client maintainer, Hammerspace
> > > trond.myklebust@hammerspace.com