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Date: Fri, 20 Dec 2013 11:21:52 +0100
From: Stefan Hajnoczi <stefanha@gmail.com>
Message-ID: <20131220102152.GG27021@stefanha-thinkpad.redhat.com>
References: <cover.1387419339.git.hutao@cn.fujitsu.com>
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In-Reply-To: <4f5c56d2ebd81d5ae3333b4894eb785ab98cf2db.1387419339.git.hutao@cn.fujitsu.com>
Subject: Re: [Qemu-devel] [RFC PATCH v3 6/6] qcow2: Add full image
 preallocation option
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To: Hu Tao <hutao@cn.fujitsu.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Peter Lieven <pl@kamp.de>, Fam Zheng <famz@redhat.com>, qemu-devel@nongnu.org

On Thu, Dec 19, 2013 at 10:27:41AM +0800, Hu Tao wrote:
> -static int preallocate(BlockDriverState *bs)
> +static int preallocate(BlockDriverState *bs, enum prealloc_mode mode)
>  {
>      uint64_t nb_sectors;
>      uint64_t offset;
> @@ -1395,9 +1395,19 @@ static int preallocate(BlockDriverState *bs)
>      int ret;
>      QCowL2Meta *meta;
>  
> +    assert(mode != PREALLOC_OFF);
> +
>      nb_sectors = bdrv_getlength(bs) >> 9;
>      offset = 0;
>  
> +    if (mode == PREALLOC_FULL) {
> +        ret = bdrv_preallocate(bs->file, 0, bdrv_getlength(bs));

This doesn't make sense since it fails to factor in qcow2 metadata and
the file layout.