JFFS2 losing dirs/files on NAND flash

[Lakshmi N. Sundararajan - PTU]

When you expose any electronic storage device to radiation of any kind,
then bit flips can definetely happen.

But instead I would suggest to think more on easily reproduceable
software defined methods. That will ensure one can see a problem
and ultimately a fix to the problem. Otherwise, this will be treated
as a ozone hole and none will be interested!

Thanks,
-LN


> -----Original Message-----
> From: linux-mtd-bounces at lists.infradead.org 
> [mailto:linux-mtd-bounces at lists.infradead.org] On Behalf Of 
> Suresh Rajashekara
> Sent: Monday, October 27, 2008 4:47 PM
> To: Marco Braga
> Cc: linux-mtd at lists.infradead.org
> Subject: Re: JFFS2 losing dirs/files on NAND flash
> 
> Hi All,
> 
> Can this happen if the flash is exposed to X-ray/MRI machines 
> or any electromagnetic radiation?
> 
> Thanks in advance.
> 
> Suresh
> 
> On Mon, Oct 27, 2008 at 9:46 AM, Suresh R 
> <suresh at mistralsolutions.com> wrote:
> > We could not switch to a new kernel because of our internal time 
> > lines, but we have made some minor modifications to the 
> application to 
> > reduce the flash usage. This, however, does not solve the 
> issue, but 
> > if GC is what is causing this, we want to reduce the number 
> of times 
> > GC triggers.
> >
> > We had even planned for partition layout with more of RO partitions 
> > and less of RW partitions so that we don't run in to this condition.
> > This would be ideal because, no matter what kernel you use.
> >
> > HTH,
> >
> > Suresh
> >
> > On Mon, Oct 27, 2008 at 9:16 PM, Marco Braga 
> <marco.braga at gmail.com> wrote:
> >> Hi,
> >>
> >> and did the problem disappear when using the new kernel? 
> How did you 
> >> solve the problem?
> >> Thank you!
> >>
> >> Marco
> >>
> >>
> >> 2008/10/27 Suresh R <suresh at mistralsolutions.com>:
> >>> Hi,
> >>>
> >>> Even I have faced a similar issue with the JFFS2 on onenand on 
> >>> 2.6.16-rc3. I too was not able to reproduce the issue by shutting 
> >>> down abruptly, but it happens on our products on the field.
> >>>
> >>> I looks to me that it happens when switched off during a GC. I am 
> >>> not sure. I was not able to prove to myself this theory. 
> Where ever 
> >>> I reported this issue, I was told to use a new kernel.
> >>>
> >>> Suresh
> >>>
> >>> On Mon, Oct 27, 2008 at 1:42 PM, Marco Braga 
> <marco.braga at gmail.com> wrote:
> >>>> Hello,
> >>>>
> >>>> I am using JFFS2 on an ARM base board with a 128Mb NAND flash, 
> >>>> kernel 2.6.22.10. Sometimes the board does not boot because a 
> >>>> directory in /etc has disappeared after a JFFS2 error or 
> a file is missing data.
> >>>> I'm trying to understand at what level (hardware, 
> kernel, MTD, file
> >>>> system) it happens. The error appears when trying to access the 
> >>>> directory or file:
> >>>>
> >>>> JFFS2 warning: (96) jffs2_do_read_inode_internal: no data nodes 
> >>>> found for ino #65
> >>>> JFFS2 notice: (96) jffs2_do_read_inode_internal: but it has 
> >>>> children so we fake some modes for it
> >>>> JFFS2 warning: (96) jffs2_do_read_inode_internal: no data nodes 
> >>>> found for ino #97
> >>>> JFFS2 notice: (96) jffs2_do_read_inode_internal: but it has 
> >>>> children so we fake some modes for it ...
> >>>>
> >>>> I've not been able to relate it to an unclean shutdown. 
> I've tried 
> >>>> powering off the board several times without being able 
> to make the 
> >>>> problem happen. Moreover I've tried a multithreaded program that 
> >>>> opens, writes, reads and deletes several files to stress 
> the FS and 
> >>>> it never happened after an overnight run.
> >>>>
> >>>> Can you please help understanding the cause or the 
> meaning of those log lines?
> >>>> Thank you!
> >>>>
> >>>> ______________________________________________________
> >>>> Linux MTD discussion mailing list
> >>>> http://lists.infradead.org/mailman/listinfo/linux-mtd/
> >>>>
> >>>
> >>
> >
> 
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