Re: [Bug-tar] Can't extract file from multivolume archive

[Alford, Seth]

On Fri, Feb 04, 2011 at 06:43:09PM -0600, Paul Eggert wrote:
> On 02/04/11 07:21, address@hidden wrote:
> > Any ideas?
> 
> Is there some simple, self-contained shell script
> that reproduces the problem without requiring access
> to special hardware?  That might help us diagnose it.
> At least we could add it to the test cases.
> 
> Otherwise, I dunno, I suppose you can use GDB to figure
> out what went wrong.
> 

I saw the same problem which stinga described, twice.  

Once, like stinga, in a non-portale environment.  

Once, while I was writing a script, test_multiple_volumes, where
I tried to get the problem to happen again.
test_multiple_volumes is attached.  

I have not been able to get the problem to repeat.

So I think that the problem which stinga saw exists, but it is
intermittent.

Information about the script are in the comment block at the
beginning of the script.  Basically it creates 3 loopback disks,
a bunch of files to write to those "disks", and experiments with
filling the disks using a tar command with the --multi-volume
option.

Rather than try to continue to get this script to "fail" in the
right way, I thought I would send it along to the list.  Maybe
someone else can get it to mis-behave.  That way we can get
the problem to repeat, and maybe get it fixed.

To get this script to work, you have to run it as root.  THIS
IS POTENTIALLY DANGEROUS.  While developing this script, it
inadvertently deposited files in the / directory, rather than
in the local directory where the script ran.  I think I fixed
that problem, but you never know.  So I recommend that you:
* go over this script very carefully before you run it,
* run it on a test machine with no important data,
* and/or run it on a test machine that may become
  non-functional without anyone caring.

To run this script, find a large empty directory on your test
machine (as described above) on a partition that has at least
1Gbyte of available disk space.  Save this script as
test_multi_volumes in that directory.  As root, type

./test_multi_volumes

By default, the script asks if you see desired output from df
at a couple of places.  Add the --noninteractive flag to get it
to just run without asking you questions.

--Seth Alford
address@hidden


This message and any attachments are intended only for the use of the addressee 
and may contain information that is privileged and confidential. If the reader 
of the message is not the intended recipient or an authorized representative of 
the intended recipient, you are hereby notified that any dissemination of this 
communication is strictly prohibited. If you have received this communication 
in error, please notify us immediately by e-mail and delete the message and any 
attachments from your system.

test_multiple_volumes
Description: Text document