[OpenWrt-Devel] Current state of extroot, how to use it, what about ubi(fs)
zajec5 at gmail.com
Tue Dec 16 05:00:33 EST 2014
I've spent few hours today trying to understand extroot. I've failed :(
Of course I was trying to use wiki pages:
1) Main question
Is the following sentence true at all?
> The configuration of extroot is very simple and is done entirely in /etc/config/fstab.
It seems that /etc/init.d/fstab uses "block umount" and "block mount"
only. I was reading the source code (fstools-2014-12-15/block.c) and
it seems that "block mount" doesn't really handle extroot at all.
I think some kind of extroot support is provided in "block extroot",
but I don't fully understand it. It seems to be looking for partitions
"rootfs" and then "rootfs_data" ignoring whatever is set in
/etc/config/fstab. If "mount extroot" is really supposed to be used,
is there any way to point some external device (without MTD
partitions) as extroot? I got confused.
2) UBI and UBIFS support
I guess it's too new to be documented and I don't understand it much
from the code. It seems that if there isn't "rootfs" MTD partition,
then the code will look for "rootfs" UBI volume. The same applies to
But what if my serial flash contains "rootfs" + "rootfs_data"
partitions and I still want to use some UBI volume on another flash
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