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Date: Mon, 22 Apr 2013 23:18:51 +0800
From: Liu Yuan <namei.unix@gmail.com>
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Subject: Re: [Qemu-devel] [PATCH v2 2/2] sheepdog: implement
	.bdrv_co_is_allocated()
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To: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Stefan Hajnoczi <stefanha@gmail.com>, sheepdog@lists.wpkg.org, qemu-devel@nongnu.org, MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>

On 04/22/2013 11:03 PM, Stefan Hajnoczi wrote:
> Imagine sector_num = 0 and nb_sectors = SD_DATA_OBJ_SIZE / BDRV_SECTOR_SIZE.
> 
> start = 0
> end = 1
> 
> You don't want object 1, only object 0.

Hmm, math, ouch. So nb_sectors include sector_num? What I mean is

If [start, end] mean a range of sectors,so

1. nb_sectors = end - start + 1 (I assume this one)
2. nb_sectors = end - start (you meant this one?)

which one is correct for .co_is_allocated?

Thanks,
Yuan