Re: jffs on non-MTD device?

[David Woodhouse]

[e-mail] said:
> I'm trying to run jffs on my ATA-flash disk (running ext2 could kill
> some flash cells too soon, right?) but it refuses:

CompactFlash does wear levelling internally. 

>         if (MAJOR(dev) != MTD_BLOCK_MAJOR) {
>                 printk(KERN_WARNING "JFFS: Trying to mount a "
>                        "non-mtd device.\n");
>                 return 0;
>         }

> What are reasons for this check? 

JFFS doesn't actually use the block device interface. Specifying it in the 
mount command is simply a hack to make life easier, which nobody's yet 
managed to obsolete. We actually use the underlying MTD device:

        mtd = get_mtd_device(NULL, MINOR(dev));

If you want JFFS (or JFFS2) on a CF device - in the apparent absence of any 
other relatively low overhead, compressing, journalling file system to use 
on it - then you need to provide a translation driver similar to the mtdram 
one which fakes an MTD device, using a block device as backing store.

--
dwmw2