Subject: Re: [PATCH 0/2]Define ext3 in-kernel filesystem block types and
	extend ext3 filesystem limit from 8TB to 16TB
From: Mingming Cao <cmm@us.ibm.com>
Reply-To: cmm@us.ibm.com
To: Andrew Morton <akpm@osdl.org>
Cc: linux-kernel@vger.kernel.org, ext2-devel@lists.sourceforge.net,
       linux-fsdevel@vger.kernel.org
In-Reply-To: <20060526110803.50380d55.akpm@osdl.org>
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Content-Type: text/plain
Organization: IBM LTC
Date: Tue, 30 May 2006 10:55:38 -0700
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On Fri, 2006-05-26 at 11:08 -0700, Andrew Morton wrote:
> Mingming Cao <cmm@us.ibm.com> wrote:
> >
> > Some of the in-kernel ext3 block variable type are treated as signed 4 bytes
> >  int type, thus limited ext3 filesystem to 8TB (4kblock size based). While
> >  trying to fix them, it seems quite confusing in the ext3 code where some
> >  blocks are filesystem-wide blocks, some are group relative offsets that need
> >  to be signed value (as -1 has special meaning). So it seem saner to define two
> >  types of physical blocks: one is filesystem wide blocks, another is
> >  group-relative blocks.  The following patches clarify these two types of
> >  blocks in the ext3 code, and fix the type bugs which limit current 32 bit ext3
> >  filesystem limit to 8TB.
> > 
> >  With this series of patches and the percpu counter data type changes in the mm
> >  tree, we are able to extend exts filesystem limit to 16TB.
> 
> Did you look at the `gcc -W' output before and after these patches are
> applied?  That would have found the bug which the previous version
> of these patches introduced.
> 
Sorry for the delay, was out for the past holiday.

Yes, I did used gcc -Wall -Wextra.  Pretty careful about it this time. 

> We already get a pile of `warning: comparison between signed and unsigned'
> warnings which should be checked, too..
> 

Yes, indeed.

Mingming

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