From: Nathan Scott <nscott@aconex.com>
Subject: Re: [PATCH 4/7][TAKE5] support new modes in fallocate
Date: Thu, 28 Jun 2007 09:28:36 +1000
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On Wed, 2007-06-27 at 23:36 +1000, David Chinner wrote:
> .... Allows setup_swap_extents() to use preallocated files on XFS
> filesystems for swap files without ever needing to convert them.

Using unwritten extents (as opposed to the MKSWAP flag mentioned
earlier) has the unfortunate down side of requiring transactions,
possibly additional IO, and memory allocation during swap.  (but,
this patch should probably go in regardless, as teaching generic
code about unwritten extents is not a bad idea).

cheers.

--
Nathan