Re: [PLUG] secure file deletion with journaling filesystems

[gabriel rosenkoetter <gr@eclipsed.net>]

On Thu, Sep 12, 2002 at 12:54:05PM -0400, Kevin Brosius wrote:
> That's an interesting question.  At least for reiser, I'd expect
> something like shred to be effective as long as the changes get written
> to disk before the system goes down.  That's because, while reiser does
> journalling, it only journals metadata (directory/file system structure)
> info.

That's the definition of a journaling file system. One which stores
all file system data (including meta-) sequentially on disk, cleaning
sectors as the data in then becomes outdated, is called a log-structured
file system. See:

  http://citeseer.nj.nec.com/rosenblum90lfs.html

> If you run a data overwrite tool on reiser, and leave enough time for
> the changes to commit to disk, I'd expect them to be completely gone. 
> The same is probably not true for other styles of journalling
> filesystems.  I'm less familiar with them.

Why wait? Heard of sync(8)?

-- 
gabriel rosenkoetter
gr@eclipsed.net

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