From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mike Snitzer <snitzer@redhat.com>
Subject: Re: [PATCH, RFC] dm: relax discard restrictions
Date: Wed, 27 Apr 2011 11:19:11 -0400
Message-ID: <20110427151911.GF7294@redhat.com>
References: <20110427150623.GC13487@infradead.org>
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To: Christoph Hellwig <hch@infradead.org>
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On Wed, Apr 27 2011 at 11:06am -0400,
Christoph Hellwig <hch@infradead.org> wrote:

> With targets like dm-thinp we might want to allow discard even if the
> underlying devices don't support them natively.  This patch is the
> extreme variant of not restricting discard support at all, but maybe
> there are other options.  Or maybe we should keep the old
> dm_table_supports_discards function as a helper for targets that
> want simple discard passthrough?

I think we could accomplish the same by adding a target override flag
(e.g. ti->discards_supported) that enables dm_table_supports_discards()
to short-circuit device_discard_capable's native discard checking.

Mike