> You noted in one of your past post(s) that you actually ran out of room
> on in your flash image for a jffs partition. I think I can see why.
> You have to put all of the needed kernel modules (usb-storage, scsi,
> etc.) into it.
You may be right, but one way or another in order to mount an external
drive, I need to have those kernel modules in the flash, whether in the
/rom or the /jffs filesystems. So maybe if I don't put them in the
/rom, I just fall below the limit and I'm able to create
a /jffs filesystem and that allows me to place the kernel modules
in there.
Note tho that the files in /rom are packed more efficiently than those
in /jffs, so it's not clear whether you'd win anything, really. On the
contrary, not using a jffs I can pack my /rom even more full (e.g. to
try and get things to be small enough for a jffs2 partition, I trimmed
down my busybox to remove httpd and other things. Now that I gave up
on jffs I can stuff my busybox with all the goodies I want and it still
fits snuggly).
Also, why bother? Since my root is really on an external drive, all
I care to have in my flash is something that mounts my drive and runs
/sbin/init. Why bother going through /jffs since this requires
no configuration.
> I guess the benefit of doing the pivot_root to the USB storage *after*
> the jffs is mounted is that you don't *have* to stuff the rom image so
> full if you don't want to mount a USB device for your root filesystem.
IIRC even without those kernel modules, the jffs partition is either too
small to work (i.e. the kernel refuses using it, typically it only has
128KB which equals to only 2 erase blocks), or it's too small to be
convenient (e.g. it kind of works but you get odd behaviors such as "ls
seg faults" and you need to use a crippled environment (busybox)).
> I think this lends itself to a more flexible flashable image, not
> bloated with usb and storage modules for those who don't want them but
> allows one to add them after one has flashed the image and still get a
> USB storage target mounted as /.
You might be right. But I'm not sure what kind of flexibility you're
looking for here.
For the wl-700ge, I have found that a jffs partition is a problem rather
than a solution: after each firmware upgrade you'd need to re-tweak it.
Whereas with my rom-only solution, I can reflash any day. I.e. my
"flash" is literally the equivalent of the typical "kernel+initrd"
packages placed usually in /boot, so I can replace it any time to
upgrade a kernel and don't have to worry about re-applying my local
config to the jffs partition.
Now, don't get me wrong: on my wrtsl54gs and its 8MB of flash, the jffs
partition is king. But in the specific case where your root is always
going to be on USB or IDE, then a jffs partition doesn't make much
sense, I think.
Stefan
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