Strange VFS problem

[Paul Marwick]

Yury V. Zaytsev wrote:
> On Tue, 2011-05-17 at 16:20 +0100, Paul Marwick wrote:
>> Yury V. Zaytsev wrote:
>>> On Mon, 2011-05-16 at 10:23 +0100, Paul Marwick wrote:
>>>
>>>> I've also checked in case it was a lack of space in /tmp, but that
>>>> doesn't seem to be the problem at all. If nothing else, one of the files
>>>> that MC is failing on is an entire 105 bytes, so it shouldn't need a lot
>>>> of space to extract. Files which are not failing are much larger.
>>> Can you provide us with one such small file to see if we can reproduce
>>> the problem or they contain sensitive / personal information?
>>>
>> As requested, here are three of the small files that I have had problems
>> reading or extracting with Midnight Commander in my backup archive. Hope
>> they're of some help.
> Ok, I'm sorry, I probably didn't understand you correctly. I was
> thinking that you have several small archives that mc consistently fails
> to extract, but apparently what you meant is that these files that
> you've sent me are the ones that mc fails to extract from the big
> archive that you have.

Sorry, I may not have explained clearly. The files I sent are ones that 
mc will not read or extract from the full archive. If I reduce the size 
of the archive, mc can then read or extract them without problems. The 
bug seems to be associated with large files. As an example, I just redid 
my backup, but excluded part of the Gmail backup from it (Gmail handles 
Imap mail in a _very_ strange way...). The two archives are as below:

-rw-r--r-- 1 root root 914849050 May 15 08:51 
backup-darkstar-20110515-084908.tar.gz
-rw-r--r-- 1 root root 477995699 May 18 17:43 
backup-darkstar-20110518-174210.tar.gz

In the larger archive, the files I sent cannot be extracted, and 
attempting to view them does nothing at all. In the smaller archive,
>
> I don't see a way to diagnose the issue without having an example
> archive that mc consistently fails to extract.

:) Its a big upload, but if necessary (and if you have somewhere I can 
upload it too), I can create a similar size archive (just missing a few 
bits of private information) and upload it. Or see if I can reproduce 
the problem in a large archive which does not contain any private 
information.
>
> If you don't have such an archive I don't see where we can go from here.
> I guess the easiest would be to try strace / ltrace and see what is
> happening when it hangs up, otherwise if you are familiar with debugging
> you could probably attach to a process as it gets stuck and see what's
> going on there.
>
Is there somewhere I can find out how to use (and save the output) of 
strace / ltrace, I'm quite happy to try that. Its more a matter of 
getting you information that is useful. I use mc a great deal, and would 
really like to see this problem fixed....

BTW, sorry if I was replying privately rather than to the list - Gmail 
handles lists in a very strange way. I may have to find some other Imap 
service I can use - it gets quite confusing at time when it comes to 
mailing lists.

Paul