how to loopback mount a JFFS2 filesystem on my linux box?

[Artem B. Bityuckiy]

On Mon, 10 Jan 2005, Josh Boyer wrote:

> On Mon, 2005-01-10 at 11:49, Robert P. J. Day wrote:
> >   i swear i once knew how to do this, but it's lost in the mists of
> > time.  i used "mkfs.jffs2" to create a simple JFFS2 image, and now i
> > just want to mount it on my fedora core 3 system using a loopback
> > mount.
> > 
> >   i have the jffs2 and mtdcore modules currently loaded, and normally,
> > what i would try is:
> > 
> >   # mkdir m
> >   # mount -o loop -t jffs2 <jffs2.img file> m
> > 
> > but what i get is:
> > 
> > # mount -o loop -t jffs2 hello.img m
> > mount: wrong fs type, bad option, bad superblock on /dev/loop0,
> >        or too many mounted file systems
> >        (could this be the IDE device where you in fact use
> >        ide-scsi so that sr0 or sda or so is needed?)
> > 
> >   i *vaguely* recall needing to do a bit more work, like loading
> > another module or two.  any pointers to a URL for this?  thanks.
> 
> You can't do that AFAIK because JFFS2 needs an MTD device.  Instead, use
> mtdram to create a fake MTD device, dd the image to it, and do:
> 
> # mount -t jffs2 /dev/mtdblock0 <mnt/point>
mtdblock is hardcoded to 4BM. So if you need larger, use nand/nandsim.c. 
This is NAND flash simulation driver and it is configurable, so you may 
configure it to have larger size. 
 
> Really though, we should look at making JFFS2 and/or the loopback driver
> grok each other.  Would be useful.  Maybe a JFFS3 candidate?
AFAIK, JFFS3 is candidate for all improvements :-)

> 
> josh
> 
> 
> 
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> 

--
Best Regards,
Artem B. Bityuckiy,
St.-Petersburg, Russia.