How to simulate journal corruption

How to simulate journal corruption

[crow al]

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Hi, there

I'm a QA engineer from Cisco. I'm working on a test case concerning XFS journal playback failure, which needs to manually inject error to XFS.

I did some google work but get no luck. Then I think maybe XFA-QA could give me some advice. That why I come to here.

Is there anyone could tell me how to inject error into XFS or is there any tool could be used?

Wish for your response.

Thanks & Regards.
Lv Wentao.

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Re: How to simulate journal corruption

[Olaf Weber]

crow al writes:

> Hi, there

> I'm a QA engineer from Cisco. I'm working on a test case concerning
> XFS journal playback failure, which needs to manually inject error
> to XFS.

> I did some google work but get no luck. Then I think maybe XFA-QA
> could give me some advice. That why I come to here.

> Is there anyone could tell me how to inject error into XFS or is
> there any tool could be used?

For clobbering a filesystem image in general you can use fsfuzz.
  http://people.redhat.com/sgrubb/files/fsfuzzer-0.7.tar.gz

If log replay is of particular interest, you might want to modify that
code to target the XFS log in particular.

The XFS QA tests do not, IIRC, contain tests that deliberately trash
the XFS log, but there are some tests that exercise log replay, and
you may want to take a look at those to see ways to get an XFS
filesystem image with a non-empty log to replay.

Note that kernel-side, if log replay fails the expected/desired result
is that kernel won't mount the filesystem.

-- 
Olaf Weber                 SGI               Phone:  +31(0)30-6696752
                           Veldzigt 2b       Fax:    +31(0)30-6696799
Technical Lead             3454 PW de Meern  Vnet:   955-7151
Storage Software           The Netherlands   Email:  olaf@sgi.com

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Re: How to simulate journal corruption

[Eric Sandeen]

crow al wrote:
> Hi, there
> 
> I'm a QA engineer from Cisco. I'm working on a test case concerning XFS
> journal playback failure, which needs to manually inject error to XFS.
> 
> I did some google work but get no luck. Then I think maybe XFA-QA could
> give me some advice. That why I come to here.
> 
> Is there anyone could tell me how to inject error into XFS or is there
> any tool could be used?
> 
> Wish for your response.
> 
> Thanks & Regards.
> Lv Wentao.

test 044 in xfstests runs something called "loggen" which will generate
log traffic to be replayed on mount, if I'm reading it right.  Of course
that's an uncorrupted log ...

There is another tool called "fsfuzzer" which writes random junk over a
filesystem.  You could probably combine the two tools to create valid
logs to replay, and then write varying degrees of junk on top with
fsfuzzer, and try to replay the result.

You could probably even use fsfuzzer "stock" and just restrict the
fuzzing to the log portion of the filesystem.

I'm not sure what kinds of errors you are trying to catch - oopses,
hangs, improperly replaying a corrupted log, etc - but it sounds well
worth doing.  FWIW when I used fsfuzzer, it often ran into problems in
the log, so I imagine you'll uncover some interesting things; if you do,
please share.  :)

-Eric

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RE: How to simulate journal corruption

[crow al]

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Hi, Olaf & Eric

Thanks for your kindly reply. I will try your suggestions & if there is any interesting findings, I will let your know

Thanks & Regards.
Lv Wentao.





> Date: Mon, 13 Jul 2009 09:44:03 -0500
> From: sandeen@sandeen.net
> To: al-john@hotmail.com
> CC: xfs@oss.sgi.com
> Subject: Re: How to simulate journal corruption
> 
> crow al wrote:
> > Hi, there
> > 
> > I'm a QA engineer from Cisco. I'm working on a test case concerning XFS
> > journal playback failure, which needs to manually inject error to XFS.
> > 
> > I did some google work but get no luck. Then I think maybe XFA-QA could
> > give me some advice. That why I come to here.
> > 
> > Is there anyone could tell me how to inject error into XFS or is there
> > any tool could be used?
> > 
> > Wish for your response.
> > 
> > Thanks & Regards.
> > Lv Wentao.
> 
> test 044 in xfstests runs something called "loggen" which will generate
> log traffic to be replayed on mount, if I'm reading it right.  Of course
> that's an uncorrupted log ...
> 
> There is another tool called "fsfuzzer" which writes random junk over a
> filesystem.  You could probably combine the two tools to create valid
> logs to replay, and then write varying degrees of junk on top with
> fsfuzzer, and try to replay the result.
> 
> You could probably even use fsfuzzer "stock" and just restrict the
> fuzzing to the log portion of the filesystem.
> 
> I'm not sure what kinds of errors you are trying to catch - oopses,
> hangs, improperly replaying a corrupted log, etc - but it sounds well
> worth doing.  FWIW when I used fsfuzzer, it often ran into problems in
> the log, so I imagine you'll uncover some interesting things; if you do,
> please share.  :)
> 
> -Eric

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RE: How to simulate journal corruption

[Wentao Lv (wentalv)]

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Hi, Eric

 

Could you tell me where I could find XFS-QA test cases? 

 

Thanks & Regards.

Lv Wentao.

 

From: crow al [mailto:al-john@hotmail.com] 
Sent: Wednesday, July 15, 2009 3:51 PM
To: Wentao Lv (wentalv)
Subject: FW: How to simulate journal corruption

 



> Date: Mon, 13 Jul 2009 09:44:03 -0500
> From: sandeen@sandeen.net
> To: al-john@hotmail.com
> CC: xfs@oss.sgi.com
> Subject: Re: How to simulate journal corruption
> 
> crow al wrote:
> > Hi, there
> > 
> > I'm a QA engineer from Cisco. I'm working on a test case concerning
XFS
> > journal playback failure, which needs to manually inject error to
XFS.
> > 
> > I did some google work but get no luck. Then I think maybe XFA-QA
could
> > give me some advice. That why I come to here.
> > 
> > Is there anyone could tell me how to inject error into XFS or is
there
> > any tool could be used?
> > 
> > Wish for your response.
> > 
> > Thanks & Regards.
> > Lv Wentao.
> 
> test 044 in xfstests runs something called "loggen" which will
generate
> log traffic to be replayed on mount, if I'm reading it right. Of
course
> that's an uncorrupted log ...
> 
> There is another tool called "fsfuzzer" which writes random junk over
a
> filesystem. You could probably combine the two tools to create valid
> logs to replay, and then write varying degrees of junk on top with
> fsfuzzer, and try to replay the result.
> 
> You could probably even use fsfuzzer "stock" and just restrict the
> fuzzing to the log portion of the filesystem.
> 
> I'm not sure what kinds of errors you are trying to catch - oopses,
> hangs, improperly replaying a corrupted log, etc - but it sounds well
> worth doing. FWIW when I used fsfuzzer, it often ran into problems in
> the log, so I imagine you'll uncover some interesting things; if you
do,
> please share. :)
> 
> -Eric

________________________________

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Re: How to simulate journal corruption

[Eric Sandeen]

Wentao Lv (wentalv) wrote:
> Hi, Eric
> 
>  
> 
> Could you tell me where I could find XFS-QA test cases?
> 

http://git.kernel.org/?p=fs/xfs/xfstests-dev.git;a=summary

is devel stuff, often a bit ahead of the "official" repo which is at:

http://oss.sgi.com/cgi-bin/gitweb.cgi?p=xfs/cmds/xfstests.git;a=summary

-Eric

> 
> Thanks & Regards.
> 
> Lv Wentao.

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