Upgrading cramfs root file system while running (DENX wrote that is not possible)I

[Antonio Di Bacco]

I'm going to develop it if I don't find elsewhere.

Bye.


On Saturday 22 April 2006 13:40, Stefan Eletzhofer wrote:
> Hi,
>
> Am 21.04.2006 um 23:32 schrieb Antonio Di Bacco:
> > Little bit off topic:
> > I decided to adopt a different strategy, the sw download web page
> > will contain
> > a java applet that will act as a tftp server, then the board will
> > be rebooted
> > and an environment variable will instruct the u-boot to tftp the
> > new software
> > from the applet. What do you think? I know that applets cannot read
> > local
> > files on the PC, unless they have a valid certificate but the user
> > should
> > trust me.
>
> nice idea IMHO. Is that applet available somewhere? That would surely
> fit my needs
> (and others probably, too).
>
> Cheers,
> Stefan.
>
> > Bye,
> > Antonio.
> >
> > On Friday 21 April 2006 22:23, Wolfgang Denk wrote:
> >> In message <200604210853.32860.david.jander at protonic.nl> you wrote:
> >>> What do you mean with "something bad could happen"?
> >>
> >> System crashes.
> >>
> >>> The only thing I can think of is pulling the power plug while
> >>> flash is
> >>> being erased or written. What else could go wrong?
> >>
> >> The kernel may try to (re-) load some pages of a  running  executable
> >> or  library  which  is  no  longer  available  (at  least  not at the
> >> addresses where they used to be). The kernel will either stumble over
> >> what it believes to be a corrupted file system,  or  load  the  wrong
> >> data -> kaboom.
> >>
> >>> We do the following: system running from read-only jffs2 partition.
> >>> Sometimes that partition is remounted read-write and single files
> >>> are
> >>> replaced, but in some occasions we need to upgrade the whole fs.
> >>> In that
> >>> case a CGI lodas the image into a ramdisk, and the upgrade
> >>> process is
> >>> started. For upgrade,
> >>
> >> You *have* to unmount the old file system here.
> >>
> >>> partition, and then "dd" again to copy the image. At that point no
> >>> critical flash-read access should be requested since dd is
> >>> already in
> >>> cache (it's
> >>
> >> The kernel might reload any page of any running executable or
> >> library.
> >>
> >> Best regards,
> >>
> >> Wolfgang Denk
> >
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