Actually, this was a co-incidence, which means that buf points to
more or less a random place.
Tigran.
----- Original Message -----
> From: "Tigran Mkrtchyan" <tigran.mkrtchyan@xxxxxxx>
> To: "trondmy" <trondmy@xxxxxxxxxxxxxxx>
> Cc: "linux-nfs" <linux-nfs@xxxxxxxxxxxxxxx>, "Anna Schumaker" <anna.schumaker@xxxxxxxxxx>
> Sent: Tuesday, 1 December, 2020 11:59:22
> Subject: Re: [PATCH v3 00/11] Add RDMA support to the pNFS file+flexfiles data channels
> More investigation...
>
> After xdr_read_pages call the xdr stream points to the
> beginning of RPC package and return the xid value on
> the next read (which should be the size of the notification bitmap).
>
>
> Regards,
> Tigran.
>
> ----- Original Message -----
>> From: "Tigran Mkrtchyan" <tigran.mkrtchyan@xxxxxxx>
>> To: "trondmy" <trondmy@xxxxxxxxxxxxxxx>
>> Cc: "linux-nfs" <linux-nfs@xxxxxxxxxxxxxxx>, "Anna Schumaker"
>> <anna.schumaker@xxxxxxxxxx>
>> Sent: Thursday, 26 November, 2020 18:17:41
>> Subject: Re: [PATCH v3 00/11] Add RDMA support to the pNFS file+flexfiles data
>> channels
>
>> 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 = be32_to_cpup(p);
>> 5858 dprintk("%s: layout size %u\n", __func__, pdev->mincount);
>> 5859 if (xdr_read_pages(xdr, pdev->mincount) != pdev->mincount)
>> 5860 return -EIO;
>> 5861
>> 5862 /* Parse notification bitmap, verifying that it is zero. */
>> 5863 p = xdr_inline_decode(xdr, 4);
>> 5864 if (unlikely(!p))
>> 5865 return -EIO;
>> 5866 len = 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@xxxxxxx>
>>> To: "trondmy" <trondmy@xxxxxxxxxxxxxxx>
>>> Cc: "linux-nfs" <linux-nfs@xxxxxxxxxxxxxxx>, "Anna Schumaker"
>>> <anna.schumaker@xxxxxxxxxx>
>>> 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:
>>>
>>>
>>> $ git bisect bad
>>> c567552612ece787b178e3b147b5854ad422a836 is the first bad commit
>>> commit c567552612ece787b178e3b147b5854ad422a836
>>> Author: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
>>> Date: Wed May 28 13:41:22 2014 -0400
>>>
>>> NFS: Add READ_PLUS data segment support
>>>
>>> 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.
>>>
>>> Signed-off-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
>>>
>>> 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(-)
>>>
>>>
>>> Regards,
>>> Tigran.
>>>
>>>
>>>
>>> ----- Original Message -----
>>>> From: "Tigran Mkrtchyan" <tigran.mkrtchyan@xxxxxxx>
>>>> To: "trondmy" <trondmy@xxxxxxxxxxxxxxx>
>>>> Cc: "linux-nfs" <linux-nfs@xxxxxxxxxxxxxxx>
>>>> Sent: Monday, 16 November, 2020 21:55:50
>>>> Subject: Re: [PATCH v3 00/11] Add RDMA support to the pNFS file+flexfiles data
>>>> channels
>>>
>>>> Hi Trond,
>>>>
>>>> I am afraid, that the fix didn't work. I bisecting it....
>>>>
>>>>
>>>> Tigran.
>>>>
>>>>
>>>> ----- Original Message -----
>>>>> From: "trondmy" <trondmy@xxxxxxxxxxxxxxx>
>>>>> To: "Tigran Mkrtchyan" <tigran.mkrtchyan@xxxxxxx>
>>>>> Cc: "linux-nfs" <linux-nfs@xxxxxxxxxxxxxxx>
>>>>> Sent: Saturday, 14 November, 2020 15:29:01
>>>>> Subject: Re: [PATCH v3 00/11] Add RDMA support to the pNFS file+flexfiles data
>>>>> channels
>>>>
>>>>> On Sat, 2020-11-14 at 00:46 +0100, Mkrtchyan, Tigran wrote:
>>>>>>
>>>>>>
>>>>>> ----- Original Message -----
>>>>>> > From: "trondmy" <trondmy@xxxxxxxxxxxxxxx>
>>>>>> > To: "Tigran Mkrtchyan" <tigran.mkrtchyan@xxxxxxx>
>>>>>> > Cc: "linux-nfs" <linux-nfs@xxxxxxxxxxxxxxx>
>>>>>> > Sent: Friday, 13 November, 2020 23:45:00
>>>>>> > Subject: Re: [PATCH v3 00/11] Add RDMA support to the pNFS
>>>>>> > file+flexfiles data channels
>>>>>>
>>>>>> > On Fri, 2020-11-13 at 22:30 +0100, Mkrtchyan, Tigran wrote:
>>>>>> > >
>>>>>> > > After more testing, it looks like that client doesn't like
>>>>>> > > notification bitmap:
>>>>>> > >
>>>>>> > >
>>>>>> > > [31576.789492] --> _nfs4_proc_getdeviceinfo
>>>>>> > > [31576.789503] --> nfs41_call_sync_prepare data->seq_server
>>>>>> > > 000000001d17c43e
>>>>>> > > [31576.789507] --> nfs4_alloc_slot used_slots=0000
>>>>>> > > highest_used=4294967295 max_slots=16
>>>>>> > > [31576.789510] <-- nfs4_alloc_slot used_slots=0001 highest_used=0
>>>>>> > > slotid=0
>>>>>> > > [31576.789527] encode_sequence:
>>>>>> > > sessionid=2910695007:150995712:0:16777216 seqid=92462 slotid=0
>>>>>> > > max_slotid=0 cache_this=0
>>>>>> > > [31576.789991] decode_getdeviceinfo: unsupported notification
>>>>>> >
>>>>>> > 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.
>>>>>>
>>>>>>
>>>>>> 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.
>>>>>>
>>>>>>
>>>>>> 0000 00 00 00 00 00 00 00 00 00 00 00 02 00 00 00 35
>>>>>> 0010 00 00 00 00 5f ae 7d ad 00 03 00 09 00 00 00 00
>>>>>> 0020 00 00 00 01 00 00 00 4c 00 00 00 00 00 00 00 0f
>>>>>> 0030 00 00 00 0f 00 00 00 00 00 00 00 2f 00 00 00 00
>>>>>> 0040 00 00 00 04 00 00 00 40 00 00 00 01 00 00 00 03
>>>>>> 0050 74 63 70 00 00 00 00 16 31 33 31 2e 31 36 39 2e
>>>>>> 0060 31 39 31 2e 31 34 33 2e 31 32 35 2e 34 39 00 00
>>>>>> 0070 00 00 00 01 00 00 00 04 00 00 00 01 00 10 00 00
>>>>>> 0080 00 10 00 00 00 00 00 01 00 00 00 02 00 00 00 06
>>>>>> 0090 00 00 00 00
>>>>>>
>>>>>>
>>>>>> the last 12 bytes : bitmap size, bitmap[0], bitmap[1]
>>>>>>
>>>>>>
>>>>>> 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.
>>>>>
>>>>> 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?
>>>>>
>>>>> 8<-------------------------------------------------------
>>>>> From e92b2d4e39e91d379ec1147115820ab5dfe4c89a Mon Sep 17 00:00:00 2001
>>>>> From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
>>>>> Date: Fri, 13 Nov 2020 21:42:16 -0500
>>>>> Subject: [PATCH] NFSv4: Fix the alignment of page data in the getdeviceinfo
>>>>> reply
>>>>>
>>>>> We can fit the device_addr4 opaque data padding in the pages.
>>>>>
>>>>> Fixes: cf500bac8fd4 ("SUNRPC: Introduce rpc_prepare_reply_pages()")
>>>>> Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
>>>>> ---
>>>>> fs/nfs/nfs4xdr.c | 14 ++++++++++----
>>>>> 1 file changed, 10 insertions(+), 4 deletions(-)
>>>>>
>>>>> 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 rpc_rqst
>>>>> *req,
>>>>> struct compound_hdr hdr = {
>>>>> .minorversion = nfs4_xdr_minorversion(&args->seq_args),
>>>>> };
>>>>> + uint32_t replen;
>>>>>
>>>>> encode_compound_hdr(xdr, req, &hdr);
>>>>> encode_sequence(xdr, &args->seq_args, &hdr);
>>>>> +
>>>>> + replen = hdr.replen + op_decode_hdr_maxsz;
>>>>> +
>>>>> encode_getdeviceinfo(xdr, args, &hdr);
>>>>>
>>>>> - /* set up reply kvec. Subtract notification bitmap max size (2)
>>>>> - * so that notification bitmap is put in xdr_buf tail */
>>>>> + /* set up reply kvec. device_addr4 opaque data is read into the
>>>>> + * pages */
>>>>> rpc_prepare_reply_pages(req, args->pdev->pages, args->pdev->pgbase,
>>>>> - args->pdev->pglen, hdr.replen - 2);
>>>>> + args->pdev->pglen, replen + 2);
>>>>> encode_nops(&hdr);
>>>>> }
>>>>>
>>>>> @@ -5848,7 +5852,9 @@ static int decode_getdeviceinfo(struct xdr_stream *xdr,
>>>>> * and places the remaining xdr data in xdr_buf->tail
>>>>> */
>>>>> pdev->mincount = be32_to_cpup(p);
>>>>> - if (xdr_read_pages(xdr, pdev->mincount) != pdev->mincount)
>>>>> + /* Calculate padding */
>>>>> + len = xdr_align_size(pdev->mincount);
>>>>> + if (xdr_read_pages(xdr, len) != len)
>>>>> return -EIO;
>>>>>
>>>>> /* Parse notification bitmap, verifying that it is zero. */
>>>>> --
>>>>> 2.28.0
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Trond Myklebust
>>>>> Linux NFS client maintainer, Hammerspace
> > > > > trond.myklebust@xxxxxxxxxxxxxxx
