On Sunday 22 March 2009 22:23:53 phcoder wrote: > Yoshinori K. Okuji wrote: > > On Sunday 22 March 2009 19:48:36 phcoder wrote: > >> Hello, I agree that non-sector aligned writes should be handled > >> correctly. However I disagree with removing of the magic number. I > >> personally would prefer if this file would have magic number and > >> checksum. AFAIK currently grub2 doesn't write to FS except in > >> load_env/save_env so a bug in code calling the hook could easily be > >> present. And I don't want grub2 to corrupt the filesystem because of any > >> such mistakes > > > > For magic, alright. But I am not certain about the necessity of checksum. > > > > Bean's code re-reads blocks so as to ensure that blocklists are identical > > to what a given filesystem driver reads. So the probability of accidental > > writes has been reduced very much already. It is hard for me to imagine > > the benefit of adding more overhead. With this condition, if a checksum > > is invalid, the cause must be either of these: > > > > - that GRUB has a bug in a filesystem driver, so this has read wrong > > sectors - that the content of grubenv has already been corrupted (e.g. > > because the user modified it mistakenly) > > > > In the latter case, there is no problem in GRUB overwriting the data, so > > we don't have to care. In the former, this means that GRUB cannot read > > the filesystem correctly anyway, so the user cannot boot any OS reliably. > > It is rather surprising that the user has successfully installed GRUB. > > This assumption doesn't hold true if developping new FS using grub-emu. > Perhaps a configure parameter to disable all writes would be a good idea?
I think you can just avoid invoking save_env. Regards, Okuji _______________________________________________ Grub-devel mailing list [email protected] http://lists.gnu.org/mailman/listinfo/grub-devel
