Re: [dm-devel] hunt for 2.6.37 dm-crypt+ext4 corruption? (was: Re: dm-crypt barrier support is effective)

[Mike Snitzer <snitzer redhat com>]

On Tue, Dec 07 2010 at  1:10pm -0500,
Jon Nelson <jnelson jamponi net> wrote:

> I finally found some time to test this out. With 2.6.37-rc4 (openSUSE
> KOTD kernel) I easily encounter the issue.
> 
> Using a virtual machine, I created a stock, minimal openSUSE 11.3 x86_64
> install, installed all updates, installed postgresql and the 'KOTD'
> (Kernel of the Day)
> kernel, and ran the following tests (as postgres user because I'm
> lazy).
> 
> 1. create a database (from bash):
> 
> createdb test
> 
> 2. place the following contents in a file (I used 't.sql'):
> 
> begin;
> create temporary table foo as select x as a, ARRAY[x] as b FROM
> generate_series(1, 10000000 ) AS x;
> create index foo_a_idx on foo (a);
> create index foo_b_idx on foo USING GIN (b);
> rollback;
> 
> 3. execute that sql:
> 
> psql -f t.sql --echo-all test
> 
> 
> With 2.6.34.7 I can re-run [3] all day long, as many times as I want,
> without issue.
> 
> With 2.6.37-rc4-13 (the currently-installed KOTD kernel) if tails
> pretty frequently.

How does it fail?  postgres errors?  kernel errors?
 
> Then I tested with the 'vanilla' kernel available here:
> 
> http://download.opensuse.org/repositories/Kernel:/vanilla/standard/
> 
> The 'vanilla' kernel exhibited the same problems.
> The version I tested:  2.6.37-rc4-219-g771f8bc-vanilla.
>
> Incidentally, quick tests of jfs, xfs, and ext3 do _not_ show the same
> problems, although I will note that I usually saw failure at least 1
> in 3, but sometimes had to re-run the sql test 4 or 5 times before I
> saw failure.
> 
> I will continue to do some testing, but I will hold off on testing the
> commits above until I receive further testing suggestions.

OK, so to be clear: your testing is on dm-crypt + ext4?

And you're testing upstream based kernels (meaning the dm-crypt
scalability patch that has been in question is _not_ in the mix)?

That is a very different report than the other 2 reports of corruption
(those corruption instances were only seen once the dm-crypt scalability
patch was introduced).

Mike