From: Chris Mason <chris.mason@oracle.com>
Subject: Re: [PATCH updated] ext4: Fix file fragmentation during large file
	write.
Date: Fri, 10 Oct 2008 15:15:18 -0400
Message-ID: <1223666118.8209.23.camel@think.oraclecorp.com>
References: <1223661776-20098-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com>
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Cc: cmm@us.ibm.com, tytso@mit.edu, sandeen@redhat.com,
	akpm@linux-foundation.org, hch@infradead.org, steve@chygwyn.com,
	npiggin@suse.de, mpatocka@redhat.com, linux-mm@kvack.org,
	inux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
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On Fri, 2008-10-10 at 23:32 +0530, Aneesh Kumar K.V wrote:
> The range_cyclic writeback mode use the address_space
> writeback_index as the start index for writeback. With
> delayed allocation we were updating writeback_index
> wrongly resulting in highly fragmented file. Number of
> extents reduced from 4000 to 27 for a 3GB file with
> the below patch.
> 
> The patch also removes the range_cont writeback mode
> added for ext4 delayed allocation. Instead we add
> two new flags in writeback_control which control
> the behaviour of write_cache_pages.
> 

I'm sorry, but I won't be able to test this until next wednesday.  In
general, I like the structure of it, and I can see this being useful for
other filesystems too.

-chris


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