linux-ext4 - Re: [PATCH 3/3] 285: Test offsets over 4GB

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Message-ID: <20130530223414.GR29466@dastard>
Date:	Fri, 31 May 2013 08:34:14 +1000
From:	Dave Chinner <david@...morbit.com>
To:	Jan Kara <jack@...e.cz>
Cc:	Eric Sandeen <sandeen@...hat.com>, xfs@....sgi.com,
	linux-ext4@...r.kernel.org
Subject: Re: [PATCH 3/3] 285: Test offsets over 4GB

On Thu, May 30, 2013 at 10:49:21PM +0200, Jan Kara wrote:
> On Thu 30-05-13 15:05:02, Eric Sandeen wrote:
> > On 5/30/13 3:01 PM, Jan Kara wrote:
> > > On Thu 30-05-13 08:48:24, Eric Sandeen wrote:
> > >> On 5/30/13 7:45 AM, Jan Kara wrote:
> > >>> Test whether SEEK_HOLE and SEEK_DATA works correctly with offsets over
> > >>> 4GB.
> > >>
> > >>
> > >> Hm, should we add 2T as well while we're at it?
> > >>
> > >> (and does this cause any new failures?)
> > >   Yes, ext4 is broken. I've sent fixes for it yesterday. I'm not sure what
> > 
> > Argh, sorry I forgot that.  I just want to be careful about more rigorous
> > tests making it look like we have regressions in the code.
> > 
> > > exactly would overflow at 2T ... block counts if signed int is used and
> > > blocksize is 1KB?
> > 
> > Hum ok, where'd I come up with 2T?  :)  never mind that maybe, unless
> > there are other potential trouble points we should add (8T? 16T for
> > filesystems that can handle it?)
>   Yeah, so 8T + something might be interesting and both ext4 & xfs should
> handle that fine. 16T + something might be interesting for xfs if it
> supports that size. I'll update this patch with these checks.

What boundary traversal are we trying to test at these high
offsets? 

I mean, I can understand wanting to confirm they work, but there's
no 32 bit variable boundary in the seek code at 8/16TB that needs to
be specifically test is there? i.e. is it just testing the same case
as the 8GB case?

Cheers,

Dave.
-- 
Dave Chinner
david@...morbit.com
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