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

[erich]

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.
And only it ocur at the volume that format with mkfs.ext2.
Thanks again.

Best Regards
Erich Chen

----- Original Message ----- 
From: "Jens Axboe" <axboe@xxxxxxx>
To: "erich" <erich@xxxxxxxxxxxx>
Cc: <dax@xxxxxxxxxxxx>; <billion.wu@xxxxxxxxxxxx>; "Al Viro" 
<viro@xxxxxxxxxxxxxxxx>; "Andrew Morton" <akpm@xxxxxxxx>; "Randy.Dunlap" 
<rdunlap@xxxxxxxxxxxx>; "Matti Aarnio" <matti.aarnio@xxxxxxxxxxx>; 
<linux-kernel@xxxxxxxxxxxxxxx>; "James Bottomley" 
<James.Bottomley@xxxxxxxxxxxx>; "Chris Caputo" <ccaputo@xxxxxxx>
Sent: Thursday, April 20, 2006 2:42 PM
Subject: Re: new Areca driver in 2.6.16-rc6-mm2 appears to be broken


> On Thu, Apr 20 2006, erich wrote:
> > Dear Jens Axboe,
> >
> > I  do "fsck -fy /dev/sda1" on driver MAX_XFER_SECTORS 512.
> > The file system was not clean.
> > I attach mesg.txt for you refer to.
> >
> > =====================================
> > == boot with driver MAX_XFER_SECTORS 4096
> > =====================================
> > #mkfs.ext2 /dev/sda1
> > #reboot
> > =====================================
> > == boot with driver MAX_XFER_SECTORS 512
> > =====================================
> > #fsck -fy /dev/sda1
> > /dev/sda1:clean,.............
> > #reboot
> > =====================================
> > == boot with driver MAX_XFER_SECTORS 4096
> > =====================================
> > #mount /dev/sda1 /mnt/sda1
> > #cp /root/aa /mnt/sda1
> > #reboot
> > =====================================
> > == boot with driver MAX_XFER_SECTORS 512
> > =====================================
> > #fsck -fy /dev/sda1
> > /dev/sda1: no clean,........and dump message such as the attach file
> > mesg.txt.
>
> So the conclusion is that your driver and/or hardware corrupts data when
> you set MAX_XFER_SECTORS too high. I can't help you anymore with this,
> you should be in the best position to debug the driver and/or hardware
> :-)
>
> It could be that the higher setting just exposes another transfer
> setting bug, like maximum number of segments or segment size, etc.
>
> --
> Jens Axboe

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