Re: block: Always check queue limits for cloned requests

[Hannes Reinecke <hare@suse.de>]

On 11/29/2015 06:05 PM, Markus Trippelsdorf wrote:
> On 2015.11.29 at 11:49 -0500, Mike Snitzer wrote:
>> On Sun, Nov 29 2015 at 11:15am -0500,
>> Markus Trippelsdorf <markus@trippelsdorf.de> wrote:
>>
>>> On 2015.11.29 at 16:43 +0100, Hannes Reinecke wrote:
>>>> On 11/29/2015 12:49 PM, Markus Trippelsdorf wrote:
>>>>>
>>>>> I'm still seeing the issue (BUG at drivers/scsi/scsi_lib.c:1096!) even
>>>>> with this patch applied.
>>>>>
>>>>> markus@x4 linux % git describe
>>>>> v4.4-rc2-215-g081f3698e606
>>>>>
>>>> Can you generate a crashdump?
>>>> I would need to cross-check with the other dumps I'm having to figure
>>>> out if this really is the same issue.
>>>> There have been other reports (and fixes) which show we're fighting
>>>> several distinct issues here.
>>>
>>> Unfortunately no. The crash happens on the disk where I store my log
>>> files. And after it happened the magic SysRq keys don't work anymore.
>>>
>>> The crash only happens on my spinning rust drive that uses the cfq
>>> scheduler. The SSDs (deadline) are fine.
>>>
>>> The BUG happens reproducibly when building http://www.sagemath.org/ on
>>> that drive.
>>
>> Are you using DM multipath?  If unsure, please let us know which
>> device(s) map to the "spinning rust drive", and provide output from:
>> lsblk
> 
> No, I'm not using DM multipath. 
> 
> /dev/sdb2 on /var type btrfs (rw,relatime,compress=lzo,noacl,space_cache)
> /dev/sdb2      btrfs     1.9T  904G  944G  49% /var
> 
> scsi 1:0:0:0: Direct-Access     ATA      ST2000DM001-1CH1 CC29 PQ: 0 ANSI: 5
> sd 1:0:0:0: [sdb] 3907029168 512-byte logical blocks: (2.00 TB/1.81 TiB)
> sd 1:0:0:0: [sdb] 4096-byte physical blocks
> sd 1:0:0:0: [sdb] Write Protect is off
> sd 1:0:0:0: [sdb] Mode Sense: 00 3a 00 00
> sd 1:0:0:0: Attached scsi generic sg1 type 0
> sd 1:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
> 
> Model Family:     Seagate Barracuda 7200.14 (AF)
> Device Model:     ST2000DM001-1CH164
> 
As Ming Lei indicated, this is probably a different issue. My patch
is for fixing multipath-failover induced I/O errors only.
So if you're not using multipath you won't be affected, neither by
the original issue triggering the BUG_ON nor my patch attempting to
fix it.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		               zSeries & Storage
hare@suse.de			               +49 911 74053 688
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