Re: [ANNOUNCE] Btrfs: a copy on write, snapshotting FS

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 6/13/07, Chris Mason <[email protected]> wrote:
On Wed, Jun 13, 2007 at 12:14:40PM -0400, Albert Cahalan wrote:
> On 6/13/07, Chris Mason <[email protected]> wrote:
> >On Wed, Jun 13, 2007 at 01:45:28AM -0400, Albert Cahalan wrote:

> >> * secure delete via destruction of per-file or per-block random crypto
> >keys
> >
> >I'd rather keep secure delete as a userland problem (or a layered FS
> >problem).  When you take backups and other copies of the file into
> >account, it's a bigger problem than btrfs wants to tackle right now.
>
> It can't be a userland problem if you allow disk blocks to move.
> Volume resizing, logging/journalling, etc. -- they combine to make
> the userland solution essentially impossible. (one could wipe the
> whole partition, or maybe fill ALL space on the volume)

Right about here is where I would insert a long story about ecryptfs, or
encryption solutions that happen all in userland.  At any rate, it is
outside the scope of v1.0, even though I definitely agree it is an
important problem for some people.

I'm sure you do have a nice long story, and I'm sure it seems
correct, but there is something not quite right about the add-on
hacks.

BTW, I'm suggesting that this be about deletion, not protection
of data you wish to keep. It covers more than just file bodies.
It covers inode data, block allocations, etc.

> >> * atomic creation of copy-on-write directory trees
> >
> >Do you mean something more fine grained than the current snapshotting
> >system?
>
> I believe so. Example: I have a linux-2.6 directory. It's not
> a mount point or anything special like that. I want to copy
> it to a new directory called wip, without actually copying
> all the blocks. To all the normal POSIX API stuff, this copy
> should look like the result of "cp -a", not hard links.

This would be a snapshot, which has to be done on a subvolume right now.
It is not as nice as being able to pick a random directory, but I've
only been able to get this far by limiting the feature scope
significantly.  What I did do was make subvolumes very cheap...just make
a bunch of them.

Can a regular user create and use a subvolume? If not, then
this doesn't work. (if so, then I have other concerns...)
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux