🚀 go-pugleaf

spc@leroy.cc.uregina.ca (SaskPower) writes:

>So many people keep asking for an undelete on Linux..... (sigh).
>Due to the nature of a multi-tasking (I mean a REAL one like linux)
>operating systems, you cannot expect to do it the way DOS does.

Well if anyone expects to do _anything_ with Linux the way that other
brain-dead OS does, then they shouldn't be using Linux! :-)

>DOS uses a disk allocation scheme which ensures that the NEWEST
>freed up space is not reallocated for a while, so you CAN recover
>a file if you have not generated a LOT of new ones before you
>attempt recovery.  This only works reliably if you don't have several
>other concurrent users ALSO generating a bunch of files, so any
>multitasking O/S generally does not do this.

An `undelete' feature IS planned for the ext2 filesystem.  The
"infractructure" is already there (always has been).  It just hasn't
been implemented yet.  (Just check out the specifications for it; the
basics are already there).

You can use debugfs from the e2fsprogs package to recover files.  But
it's a tricky business, especially when recovering long files that
have indirect inode references in the primary inode block.  But it can
be done (I've done it).

>What you CAN do if you must:

>Use either GNU mv or BSD mv which have OPTION flags to prevent

Yeah, easy enough to do.  There's such a package already available on
sunsite.unc.edu.  But what if you are using a filemanager or whatever
and going through an unlink(2) system call?  (I suppose that you make
sure you have a `safe delete' option turned on :)

>The linux FAQ says this kind of thing is possible, (Question 4.1)
>but does not give details... Since this question is ASKED so often,
>maybe these rough details should be included...

I agree.  debugfs is the current - but rather crude - way to do it.

>I personally don't think Theodore T'so should be spending time
>with an undelete to ext2 filesystem to handle this, as the above is
>so easy to confiugure to your needs and would be more reliable
>than changes to a filesystem... ext2 is just GREAT the way it is... 8^)

Again, in complete agreement.  But from what I can gather, it is being
worked on.  I've got no idea why it's taking so long though.

Cheers
Tony
     o o o o o o o . . .
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   .][__n_n_|DD[  ====_______| |Griffith Uni | | T.Nugent@sct.gu.edu.au     |
  >(||      |  | [Tony Nugent] |Brisbane Aust| | tnugent@gucis.cit.gu.edu.au|
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