Re: undelete?

Tall cool one (
Fri, 25 Jul 1997 11:01:45 -0500

linux kernel account <> writes:
> On Thu, 24 Jul 1997, Kurt Huwig wrote:
> > Hello!
> > In the FAQ, I just found "please wait".
> > Is anyone working on an 'undelete'-feature for ext2 or better any
> > filesystem? I don't need 'rm' replacements, because I want to undelete
> > files deleted by samba.
> Do it in userspace! Modify samba or libc.. and let all of us enjoy the
> high performance of ext2... Or make a logging filesystem and make the
> highavailibity people happy.. But, if you insist on modifying ext2 for the
> sole purpose of undeletion, you will probably be working alone.. But, I'm
> sure there would be a few people who would use your patches..

How would not zeroing file pointer and indirect blocks slow down ext2? If
anything supporting undelete in the form of "I'm not going to make it
impossible for you to recover this file yourself" should make ext2 faster.

Ext2 has everything it needs to support undelete in a reasonable fashion I
imagine, don't see why this couldn't be a compile time option or just a
patch that people could use if they want it. Of course someone needs to do
the coding, and there's the rub. =)

> Hmm, what work is being done on an ext2 replacement anyways? I doubt we
> will ever see compression as anything other then patches.. And since it
> breaks backwards compt if you use it I'm sure people would complain..
> Maby there should be some thought on producing two new filesystems for
> linux.. One as a logging system that is very reliable and maby not so
> fast. and the other a triditional one with great performance... Both of
> them maby with no ability to work on small drives.. (use ext2 for that)..
> And maby both of them have the ability to talk with a userspace daemon
> (ala kerneld) that could compress and decomress (maby 2 daemons for smp).
> They could also do delayed compression ala Netware 4.x (I really like
> netware's 'disuse' compression tacticts..).

Doing nifty things like seeking, mmap'ing, etc, with transparently
compressed files is not trivial to do, at least not effeciently, which is
why you don't see it in use everywhere. Compression should be left to user
space apps, which can be written to deal with the problem in a more sane
manner. Unix makes accessing good compression fairly trivial, so I think
it's best left to userland.

- Steve

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