Re: [RFC PATCH 1/1] add a jbd option to force an unclean journal state

Jan Kara
2008-03-04T19:01:12Z

Hi,

On Tue 04-03-08 13:39:41, Josef Bacik wrote:
> jbd and I want a way to verify that I'm not screwing anything up in the
> process, and this is what I came up with. Basically this option would only be
> used in the case where someone mounts an ext3 image or fs, does a specific IO
> operation (create 100 files, write data to a few files etc), unmounts the fs
> and remounts so that jbd does its journal recovery and then check the status of
> the fs to make sure its exactly the way its expected to be. I'm not entirely
> sure how usefull of an option like this would be (or if I did it right :) ),
> but I thought I'd throw it out there in case anybody thinks it may be useful,
> and in case there is some case that I'm missing so I can fix it and better make
> sure I don't mess anything up while doing stuff. Basically this patch keeps us
> from resetting the journal's tail/transaction sequence when we destroy the
> journal so when we mount the fs again it will look like we didn't unmount
> properly and recovery will occur. Any comments are much appreciated,
Actually, there is a different way how we've done checking like this (and
I think also more useful), at least for ext3. Basically you mounted a
filesysteem with some timeout and after the timeout, device was forced
read-only. And then you've checked that the fs is consistent after journal
replay. I think Andrew had the patches somewhere...

Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR