Re: new Areca driver in 2.6.16-rc6-mm2 appears to be broken

erich
2006-04-20T09:34:08Z

Dear Dear Jens Axboe,

I will try debench on the fs with larger xfer size when I enter my Lab. next
time.
In the previous testing I do iometer and bonnie++ bench with ext3 riserfs
file system.
I have test the transfer size from 2K to 5M with random/sequence read/write
each term 2 hours.
When those three testing platforms all have completion.
There were not any one message appear as this.
I have done same testing with ext2 512 sectors and all done well.
I will find the difference of each LBA value , request length between 512
sectors and 4096 sectors.

Best Regards
Erich Chen
----- Original Message -----
From: "Jens Axboe" <axboe@suse.de>
To: "erich" <erich@areca.com.tw>
Cc: <dax@gurulabs.com>; <billion.wu@areca.com.tw>; "Al Viro"
<viro@ftp.linux.org.uk>; "Andrew Morton" <akpm@osdl.org>; "Randy.Dunlap"
<rdunlap@xenotime.net>; "Matti Aarnio" <matti.aarnio@zmailer.org>;
<linux-kernel@vger.kernel.org>; "James Bottomley"
<James.Bottomley@steeleye.com>; "Chris Caputo" <ccaputo@alt.net>
Sent: Thursday, April 20, 2006 4:23 PM
Subject: Re: new Areca driver in 2.6.16-rc6-mm2 appears to be broken

>
> (don't top post!)
>
> On Thu, Apr 20 2006, erich wrote:
>> Dear Dear Jens Axboe,
>>
>> Thanks for your notification and advice.
>> Areca's firmware has max sg entries of 38 limit.
>> In my debug driver I had add this condition check.
>> But no one request more than 38 sg.
>> Both transfer length all have a lot of requests equal with 38 sg.
>> But why it ocur only at 4096 sectors?
>> If the /sys/block/sda/queue/max_sectors_kb equal 256 all operation
>> running
>> well.
>> But if I modify it more than 256, the bug appeared.
>> I will do more research about why there were a lot of requests equal
>> with
>> 38 sg in all file system.
>
> It was just a suggestion, the bug might very well be just the size of
> the transfer itself and nothing SG related. All I can say for sure is
> that I'd be very surprised if this fs corruption isn't due to the
> hardware mangling the data for large transfers.
>
>> And only it ocur at the volume that format with mkfs.ext2.
>
> Most likely a coincidence, try running eg dbench or other stress tests
> on the fs with larger xfer size and I'm sure it'll corrupt eventually as
> well.
>
>
> --
> Jens Axboe
>