Upgrading cramfs root file system

Antonio Di Bacco antonio.dibacco at aruba.it
Fri Apr 21 05:54:45 EST 2006

Yes you are right, it is not a good idea to overwrite working cramfs 
filesystem. But what happens if I download the new cramfs plus kernel in RAM, 
do a checksum and then, completely in kernel mode, disabling all the 
interrupts, I write to flash? No process could complain that I am overwriting 
because no one is executing.


On Wednesday 19 April 2006 09:42, Wojciech Kromer wrote:
> Dnia 2006-04-06 22:38, Użytkownik Antonio Di Bacco napisał:
> > Hi,
> >
> > how could I upgrade my cramfs rootfs? I have a CGI in the rootfs that
> > receives the new rootfs from a web interface and then tries to write it
> > in the flash. While overwriting the old cramfs, the CGI will continue to
> > work? something weird could happen?
> Generally it's not a good idea to override working filesystem ( I've
> tried to do it once).
> You can have two separate copies of filesystem, one to work with, and
> another to overwrite, it requires more flash.
> Another way is working in initrd, it requires more RAM.
> You can also use jffs2 or jffs3 (experimental) to have read-write
> filesystem, and change applications only, not whole filesystem (be
> carefull with changing busybox or libraries!)

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