jffs super block

jffs super block

[Rogelio M. Serrano Jr.]

Does the jffs also have a super block on disk?

I have been trying to use jffs on DOC but i just cant get it to mount.
The jffs code could not find a single valid jffs inode on the DOC and
then dumps the disk data and then hang when I mount it after i dd a jffs
image to the it. The second time I boot I dont get any kind of output
anymore and my machine hangs. For starters, How should I write the jffs
file system on the DOC then? Should  I add a superblock on the chip?



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Re: jffs super block

[Alexander Larsson]

On Wed, 5 Jul 2000, Rogelio M. Serrano Jr. wrote:

> Does the jffs also have a super block on disk?
> 
> I have been trying to use jffs on DOC but i just cant get it to mount.
> The jffs code could not find a single valid jffs inode on the DOC and
> then dumps the disk data and then hang when I mount it after i dd a jffs
> image to the it. The second time I boot I dont get any kind of output
> anymore and my machine hangs. For starters, How should I write the jffs
> file system on the DOC then? Should  I add a superblock on the chip?

No, jffs doesn't have a superblock. I usually just cat
my_filesystem_image > /dev/mtd0, but an empty mtd device should work as
well.

The hang seems strange though.

/ Alex






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Re: jffs super block

[David Woodhouse]

rogelio@evoserve.com said:
>  I have been trying to use jffs on DOC but i just cant get it to
> mount. 

You'll need to modify the doc2000 driver to be slightly better-behaved 
first. Currently, it refuses to do any writes which aren't 512-byte page 
aligned, and 512 bytes long, because it's only ever been used by the NFTL 
code so far. 

Once we've done that, JFFS looks like it ought to work OK, but remember that 
the DiskOnChip has NAND flash, and JFFS was designed to work on NOR flash. 

It looks to me as if it should be OK, but it's not tested on NAND flash yet.



--
dwmw2




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Re: jffs super block

[Sébastien Côté]

"Rogelio M. Serrano Jr." wrote:
> 
> Does the jffs also have a super block on disk?
> 
> I have been trying to use jffs on DOC but i just cant get it to mount.
> The jffs code could not find a single valid jffs inode on the DOC and
> then dumps the disk data and then hang when I mount it after i dd a jffs
> image to the it. The second time I boot I dont get any kind of output
> anymore and my machine hangs. For starters, How should I write the jffs
> file system on the DOC then? Should  I add a superblock on the chip?
> 
> To unsubscribe, send "unsubscribe mtd" to majordomo@infradead.org

I don't really know much about the DOC but doesn't it have it's own
filesystem (TrueFS or something like that) ?  If so, are linux drivers
available and open-sourced ?

Thanks,

-- 
Sébastien Côté


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Re: jffs super block

[David Woodhouse]

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On Thu, 6 Jul 2000, [iso-8859-1] Sébastien Côté wrote:

> I don't really know much about the DOC but doesn't it have it's own
> filesystem (TrueFS or something like that) ?  If so, are linux drivers
> available and open-sourced ?

The DiskOnChip is just a clever way of attaching NAND flash chips to a
CPU. Generally it comes with the NAND Flash Translation Layer, which
emulates a block device, on top of which you put a 'normal' filesystem.

You end up with a journalled filesystem on top of what is essentially
already a journalled filesystem, and although we do have GPL'd NFTL
support, it's not 100% reliable yet.


-- 
dwmw2




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