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From:   Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Date:   Mon, 16 Apr 2018 14:36:31 +0530
Message-ID: <CAK=zhgrT7UA8h84cCOcbkdH-wsL32_H=WLawNMgW89Vtmcu5WA@mail.gmail.com>
Subject: Re: [PATCH v2] block: ratelimite pr_err on IO path
To:     Jinpu Wang <jinpu.wang@profitbricks.com>
Cc:     "Martin K. Petersen" <martin.petersen@oracle.com>,
        Jens Axboe <axboe@kernel.dk>, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        "Elliott, Robert (Persistent Memory)" <elliott@hpe.com>,
        Suganath Prabu Subramani 
        <suganath-prabu.subramani@broadcom.com>,
        Chaitra P B <chaitra.basappa@broadcom.com>,
        linux-scsi <linux-scsi@vger.kernel.org>
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On Mon, Apr 16, 2018 at 1:46 PM, Jinpu Wang <jinpu.wang@profitbricks.com> wrote:
> On Fri, Apr 13, 2018 at 6:59 PM, Martin K. Petersen
> <martin.petersen@oracle.com> wrote:
>>
>> Jinpu,
>>
>> [CC:ed the mpt3sas maintainers]
>>
>> The ratelimit patch is just an attempt to treat the symptom, not the
>> cause.
> Agree. If we can fix the root cause, it will be great.
>>
>>> Thanks for asking, we updated mpt3sas driver which enables DIX support
>>> (prot_mask=0x7f), all disks are SATA SSDs, no DIF support.
>>> After reboot, kernel reports the IO errors from all the drives behind
>>> HBA, seems for almost every read IO, which turns the system unusable:
>>> [   13.079375] sda: ref tag error at location 0 (rcvd 143196159)
>>> [   13.079989] sda: ref tag error at location 937702912 (rcvd 143196159)
>>> [   13.080233] sda: ref tag error at location 937703072 (rcvd 143196159)
>>> [   13.080407] sda: ref tag error at location 0 (rcvd 143196159)
>>> [   13.080594] sda: ref tag error at location 8 (rcvd 143196159)
>>
>> That sounds like a bug in the mpt3sas driver or firmware. I guess the
>> HBA could conceivably be operating a SATA device as DIX Type 0 and strip
>> the PI on the drive side. But that doesn't seem to be a particularly
>> useful mode of operation.
>>
>> Jinpu: Which firmware are you running? Also, please send us the output
>> of:
>>
>>         sg_readcap -l /dev/sda
>>         sg_inq -x /dev/sda
>>         sg_vpd /dev/sda
>>
> Disks are INTEL SSDSC2BX48, directly attached to HBA.
> LSISAS3008: FWVersion(13.00.00.00), ChipRevision(0x02), BiosVersion(08.11.00.00)
> mpt3sas_cm2: Protocol=(Initiator,Target),
> Capabilities=(TLR,EEDP,Snapshot Buffer,Diag Trace Buffer,Task Set
> Full,NCQ)
>
> jwang@x:~$ sudo sg_vpd /dev/sdz
> Supported VPD pages VPD page:
>   Supported VPD pages [sv]
>   Unit serial number [sn]
>   Device identification [di]
>   Mode page policy [mpp]
>   ATA information (SAT) [ai]
>   Block limits (SBC) [bl]
>   Block device characteristics (SBC) [bdc]
>   Logical block provisioning (SBC) [lbpv]
> jwang@x:~$ sudo sg_inq -x /dev/sdz
> VPD INQUIRY: extended INQUIRY data page
>     inquiry: field in cdb illegal (page not supported)
> jwang@x:~$ sudo sg_readcap -l /dev/sdz
> Read Capacity results:
>    Protection: prot_en=0, p_type=0, p_i_exponent=0
>    Logical block provisioning: lbpme=1, lbprz=1
>    Last logical block address=937703087 (0x37e436af), Number of
> logical blocks=937703088
>    Logical block length=512 bytes
>    Logical blocks per physical block exponent=3 [so physical block
> length=4096 bytes]
>    Lowest aligned logical block address=0
> Hence:
>    Device size: 480103981056 bytes, 457862.8 MiB, 480.10 GB
>
>
>> Broadcom: How is DIX supposed to work for SATA drives behind an mpt3sas
>> controller?

[Sreekanth] Current Upstream mpt3sas driver doesn't have DIX support
capabilities,
it supports only DIF feature.


Thanks,
Sreekanth
>>
>> --
>> Martin K. Petersen      Oracle Linux Engineering
>
>
> Thanks!
>
> --
> Jack Wang
> Linux Kernel Developer
>
> ProfitBricks GmbH
> Greifswalder Str. 207
> D - 10405 Berlin