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Date: Wed, 14 Sep 2011 17:44:22 +0200
From: Christoph Hellwig <hch@lst.de>
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Subject: Re: [Qemu-devel] [PATCH 06/12] nbd: support NBD_CMD_TRIM in
	the	server
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To: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-devel@nongnu.org

On Thu, Sep 08, 2011 at 05:24:59PM +0200, Paolo Bonzini wrote:
> Map it to bdrv_discard.  The server can now expose NBD_FLAG_SEND_TRIM.

Note that discard support without a way to communicate the alignment/size
requirements, and without the discard_zeroes_data flag is pretty much
useless.  Can you work with the upstream developers to make sure it's
actually useful?