Re: Where is ext2/3 secure delete ("s") attribute?

[Jeff Garzik <jgarzik@pobox.com>]

Albert D. Cahalan wrote:

> Jeff Garzik writes:
>
> >Albert D. Cahalan wrote:
>
>
> >>Forget the shred program. It's less useful than having the
> >>filesystem simply zero the blocks, because it's slow and you
> >>can't be sure to hit the OS-visible blocks.
> >
> >Why not?
> >
> >Please name a filesystem that moves allocated blocks around on you.  And
> >point to code, too.
>
>
> Reiserfs tails
>   fs/reiserfs


inodes don't move

> ext3 with data journalling
>   fs/ext3


the allocated blocks don't change


> the journalling flash filesystems
>   fs/jffs
>   fs/jffs2


yep

> NTFS with compression
>   fs/ntfs


the allocated blocks don't change


> Multiple overwrites won't protect you from the disk manufacturer
> or the NSA. Only one is needed to protect against root & kernel.
> So it makes sense to have the filesystem zero the blocks when
> they are freed from a file.


if you need to protect against root, then zeroing the blocks isn't going 
to help for LVM or jffs or other journalling.

	Jeff