Re: Ext2fs for pupa

[Yoshinori Okuji]

 --- Marco Gerards <address@hidden> wrote:
> Were you serious about 400MB?  Normally you won't log data, only
> metadata.  And many blocks in the log are for the same diskblock
> AFAIK.  That means that you will use the last.  Anyway, I can test
> this and find out how this works. :)

I'm serious... 400MB is a theoretical value, but the default size 4MB is
already very large for small machines.
 
> Do you have an idea how I can get a unreadable filesystem that I can
> use to test the ext3 stuff on? :)

Ummh, difficult! We had a report that someone had such a filesystem so he
couldn't boot GRUB several months ago, but I don't think it is reproducible.

How about this kind of script:

[Make an ext3 on a file.]
while true; do
  [Boot user-mode-linux with it.]
  [Wait some seconds and kill the process.]
  [Check if it is unreadable by e2tools or the grub shell.]
  [ $? -eq 0 ] && break
done

> A generic cache will be interesting.  I've noticed listing files
> wasn't fast with GRUB, this can and IMHO should be changed. :)

Note that PUPA has a better general cache system already. Please see
"kern/disk.c" for more details.

But sometimes it is a good idea to have a cache system specific to a task.
That's why I said that it would be good to have a cache mechanism for
journaling data.

Okuji