Wrong data CRC in data node

Wrong data CRC in data node

[Jesper Saxtorph]

Hi

We have embedded systems where we get errors if the system is not allowed to
make a clean shutdown (that is taking the power or letting the watchdog make
a reset).
The full message we get is:
JFFS2 notice: (683) check_node_data: wrong data CRC in data node at 0x0016abe0: 
read 0x8d31ae61, calculated 0x46201a37
The addresses is not fixed, they change.
The 683 process is jffs2_gcd_mtd2.

We have the following setup:
Atmel at91
Dataflash memory
Kernel 2.6.19 with patches from http://maxim.org.za/at91_26.html

We have used kernel 2.6.12 earlier with no problems.

The errors are at our root partition, our only mounted flash.
If we mount root as read-only, the errors will not come.

I have search the net for related problems but not been able to find anything
usefull.

To get debug information I did the following:
I have added debug level 2 (noisy) in jffs2.
I have commented out #undef DEBUG_DATAFLASH in at91_dataflash.c
I have commented out #undef DEBUG_SPI in at91_spi.c

This did not give me any further information.

I wonder if there can be some kind of cache active (in 2.6.19 contra 2.6.12) we
are not aware of, that we should deactivate.

Is this a know this issue?

Any suggestions to what I could try?

With hope for suggestions,
Jesper Saxtorph
_____________________________________

Jesper Saxtorph
Software Developer

Prevas A/S
Frederikskaj 6
DK-2450 København SV

Phone +45 33159090

jesper.saxtorph@prevas.dk
www.prevas.dk

Re: Wrong data CRC in data node

[Josh Boyer]

On Wed, 14 Nov 2007 13:23:32 +0100
"Jesper Saxtorph" <Jesper.Saxtorph@prevas.dk> wrote:

> I wonder if there can be some kind of cache active (in 2.6.19 contra 2.6.12) we
> are not aware of, that we should deactivate.
> 
> Is this a know this issue?
> 
> Any suggestions to what I could try?

Check to see if CONFIG_JFFS2_FS_WRITEBUFFER is set.  If so, you can try
turning that off.

josh

RE: Wrong data CRC in data node

[Jesper Saxtorph]

> From: linux-mtd-bounces@lists.infradead.org [mailto:linux-mtd-
> bounces@lists.infradead.org] On Behalf Of Josh Boyer
> Sent: 14. november 2007 15:37
> 
> On Wed, 14 Nov 2007 13:23:32 +0100
> "Jesper Saxtorph" <Jesper.Saxtorph@prevas.dk> wrote:
> 
> > I wonder if there can be some kind of cache active (in 2.6.19 contra
> 2.6.12) we
> > are not aware of, that we should deactivate.
> >
> > Is this a know this issue?
> >
> > Any suggestions to what I could try?
> 
> Check to see if CONFIG_JFFS2_FS_WRITEBUFFER is set.  If so, you can
try
> turning that off.

The description of the mentioned kernel option states that "This
functionality is required" for DataFlash.
Therefore it is enabled and was it also on kernel 2.6.12

If I try anyway I get:
jffs2: Cannot operate on DataFlash unless jffs2 DataFlash support is
compiled in.
No filesystem could mount root, tried:  jffs2
Kernel panic - not syncing: VFS: Unable to mount root fs on
unknown-block(31,2)

So I guess the kernel option describtion is correct.

-Jesper