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Date: Wed, 26 Jun 2013 08:44:47 +0530
From: Bharata B Rao <bharata@linux.vnet.ibm.com>
Message-ID: <20130626031447.GD9966@in.ibm.com>
References: <20130625113911.GD3539@dhcp-200-207.str.redhat.com>
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In-Reply-To: <20130625113911.GD3539@dhcp-200-207.str.redhat.com>
Subject: Re: [Qemu-devel] block: Review of .has_zero_init use
Reply-To: bharata@linux.vnet.ibm.com
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To: Kevin Wolf <kwolf@redhat.com>
Cc: josh.durgin@dreamhost.com, tailai.ly@taobao.com, Peter Lieven <pl@kamp.de>, qemu-devel@nongnu.org, rjones@redhat.com, stefanha@redhat.com, morita.kazutaka@lab.ntt.co.jp

On Tue, Jun 25, 2013 at 01:39:11PM +0200, Kevin Wolf wrote:
> 
> Can you please review for the gluster, rbd, sheepdog and ssh driver
> whether it's safe to assume that the image reads back as zeros after
> bdrv_create?

Gluster supports both file and block backends. While the above is true for
file backend (which uses ftruncate), the same is not true for
block backend (which uses lvcreate & lvresize).

So overall it is not safe to assume that an image on GlusterFS volume
reads back as zeroes after create.

Regards,
Bharata.