Subject: Re: Btrfs for mainline
From: Chris Mason <chris.mason@oracle.com>
To: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
       linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org
In-Reply-To: <20090103.013755.42849152.ryusuke@osrg.net>
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Date: Fri, 02 Jan 2009 13:06:24 -0500
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On Sat, 2009-01-03 at 01:37 +0900, Ryusuke Konishi wrote:
> Hi,
> On Wed, 31 Dec 2008 18:19:09 -0500, Chris Mason <chris.mason@oracle.com> wrote:
> > 
> > This has only btrfs as a module and would be the fastest way to see
> > the .c files.  btrfs doesn't have any changes outside of fs/Makefile and
> > fs/Kconfig
> 
> I found some overlapping (or cloned) functions in
> btrfs-unstable.git/fs/btrfs, for example:
> 
>  - Declarations to apply hardware crc32c in fs/btrfs/crc32c.h:
>    The same code is found in arch/x86/crypto/crc32c-intel.c
> 

Yes, I can just remove the btrfs version of this for now.

>  - btrfs_wait_on_page_writeback_range() and btrfs_fdatawrite_range():
>    These are clones of wait_on_page_writeback_range() and
>    __filemap_fdatawrite_range() respectively, and can be removed if they
>    are just exported.
> 
>  - Copies of add_to_page_cache_lru() found in compression.c and extent_io.c
>    (can be replaced if it's exported)
> 
> How about including patches to resolve these in the btrfs kernel tree
> (or patchset to be posted) ?
> 

My plan was to export those after btrfs was actually in.  But on Monday
I'll send along a patch to export them and make compat functions in
btrfs.

> In addition, there seem to be well-separated reusable routines such as
> async-thread (enhanced workqueue) and extent_map.  Do you intend to
> move these into lib/ or so?
> 
> I also tried scripts/checkpatch.pl against btrfs, and it has detected
> 45 ERRORs and 93 WARNINGs.  I think it's a good opportunity to clean
> up these violations.

Good point, thanks for looking at the code.

-chris


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