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From: Krishnamraju Eraparaju <krishna2@chelsio.com>
To: Sagi Grimberg <sagi@grimberg.me>
Cc: Bernard Metzler <BMT@zurich.ibm.com>,
	Christoph Hellwig <hch@lst.de>,
	linux-nvme@lists.infradead.org, linux-rdma@vger.kernel.org,
	Nirranjan Kirubaharan <nirranjan@chelsio.com>,
	Potnuri Bharat Teja <bharat@chelsio.com>
Subject: Re: broken CRCs at NVMeF target with SIW & NVMe/TCP transports
Date: Wed, 18 Mar 2020 00:47:44 +0530	[thread overview]
Message-ID: <20200317191743.GA22065@chelsio.com> (raw)
In-Reply-To: <70b13212-faa6-d634-8beb-55ba39891d7f@grimberg.me>

On Tuesday, March 03/17/20, 2020 at 09:39:39 -0700, Sagi Grimberg wrote:
> 
> >>>For TCP we can set BDI_CAP_STABLE_WRITES.  For RDMA I don't think
> >>that
> >>>is a good idea as pretty much all RDMA block drivers rely on the
> >>>DMA behavior above.  The answer is to bounce buffer the data in
> >>>SoftiWARP / SoftRoCE.
> >>
> >>We already do, see nvme_alloc_ns.
> >>
> >>
> >
> >Krishna was getting the issue when testing TCP/NVMeF with -G
> >during connect. That enables data digest and STABLE_WRITES
> >I think. So to me it seems we don't get stable pages, but
> >pages which are touched after handover to the provider.
> 
> Non of the transports modifies the data at any point, both will
> scan it to compute crc. So surely this is coming from the fs,
> Krishna does this happen with xfs as well?
Yes, but rare(took ~15min to recreate), whereas with ext3/4
its almost immediate. Here is the error log for NVMe/TCP with xfs.

dmesg at Host:
[  +0.000323] nvme nvme2: creating 12 I/O queues.
[  +0.008991] nvme nvme2: Successfully reconnected (1 attempt)
[ +25.277733] blk_update_request: I/O error, dev nvme2n1, sector 0 op
0x3:(DISCARD) flags 0x800 phys_seg 1 prio class 0
[  +6.043879] XFS (nvme2n1): Mounting V5 Filesystem
[  +0.017745] XFS (nvme2n1): Ending clean mount
[  +0.000174] xfs filesystem being mounted at /mnt supports timestamps
until 2038 (0x7fffffff)
[Mar18 00:14] nvme nvme2: Reconnecting in 10 seconds...
[  +0.000453] nvme nvme2: creating 12 I/O queues.
[  +0.009216] nvme nvme2: Successfully reconnected (1 attempt)
[Mar18 00:43] nvme nvme2: Reconnecting in 10 seconds...
[  +0.000383] nvme nvme2: creating 12 I/O queues.
[  +0.009239] nvme nvme2: Successfully reconnected (1 attempt)


dmesg at Target:
[Mar18 00:14] nvmet_tcp: queue 9: cmd 17 pdu (4) data digest error: recv
0x8e85d882 expected 0x9a46fac3
[  +0.000011] nvmet: ctrl 1 fatal error occurred!
[ +10.240266] nvmet: creating controller 1 for subsystem nvme-ram0 for
NQN nqn.2014-08.org.nvmexpress.chelsio.
[Mar18 00:42] nvmet_tcp: queue 7: cmd 89 pdu (4) data digest error: recv
0xc0ce3dfd expected 0x7ee136b5
[  +0.000012] nvmet: ctrl 1 fatal error occurred!
[Mar18 00:43] nvmet: creating controller 1 for subsystem nvme-ram0 for
NQN nqn.2014-08.org.nvmexpress.chelsio.


  reply	other threads:[~2020-03-17 19:20 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-16 16:20 broken CRCs at NVMeF target with SIW & NVMe/TCP transports Krishnamraju Eraparaju
2020-03-17  9:31 ` Bernard Metzler
2020-03-17 12:26   ` Tom Talpey
2020-03-17 12:45 ` Christoph Hellwig
2020-03-17 13:17   ` Bernard Metzler
2020-03-17 16:03   ` Sagi Grimberg
2020-03-17 16:29     ` Bernard Metzler
2020-03-17 16:39       ` Sagi Grimberg
2020-03-17 19:17         ` Krishnamraju Eraparaju [this message]
2020-03-17 19:33           ` Sagi Grimberg
2020-03-17 20:31             ` Krishnamraju Eraparaju
2020-03-18 16:49               ` Sagi Grimberg
2020-03-20 14:35                 ` Krishnamraju Eraparaju
2020-03-20 20:49                   ` Sagi Grimberg
2020-03-21  4:02                     ` Krishnamraju Eraparaju

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