Re: [PATCH v3 00/11] Add RDMA support to the pNFS file+flexfiles data channels

["Mkrtchyan, Tigran" <tigran.mkrtchyan@desy.de>]

Hi Trond,

I am afraid, that the fix didn't work. I bisecting it.... 


Tigran.


----- 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+flexfiles data channels

> On Sat, 2020-11-14 at 00:46 +0100, Mkrtchyan, Tigran wrote:
>> 
>> 
>> ----- 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
>> 
>> > 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@hammerspace.com>
> 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@hammerspace.com>
> ---
> 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@hammerspace.com