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Date:   Sun, 16 Apr 2023 22:30:44 +0800
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Subject: Re: [PATCH V3] erofs: support flattened block device for multi-blob
 images
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To:     Jia Zhu <zhujia.zj@bytedance.com>, xiang@kernel.org,
        gerry@linux.alibaba.com, linux-erofs@lists.ozlabs.org,
        jefflexu@linux.alibaba.com
Cc:     linux-kernel@vger.kernel.org, huyue2@coolpad.com,
        Xin Yin <yinxin.x@bytedance.com>
References: <8be37b4c-5a87-1c10-b0e6-99284e6fd4ca@linux.alibaba.com>
 <20230302071751.48425-1-zhujia.zj@bytedance.com>
From:   Chao Yu <chao@kernel.org>
In-Reply-To: <20230302071751.48425-1-zhujia.zj@bytedance.com>
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On 2023/3/2 15:17, Jia Zhu wrote:
> In order to support mounting multi-blobs container image as a single
> block device, add flattened block device feature for EROFS.
> 
> In this mode, all meta/data contents will be mapped into one block
> address. User could compose a block device(by nbd/ublk/virtio-blk/
> vhost-user-blk) from multiple sources and mount the block device by
> EROFS directly. It can reduce the number of block devices used, and
> it's also benefits in both VM file passthrough and distributed storage
> scenarios.
> 
> You can test this using the method mentioned by:
> https://github.com/dragonflyoss/image-service/pull/1111
> 1. Compose a (nbd)block device from multi-blobs.
> 2. Mount EROFS on mntdir/.
> 3. Compare the md5sum between source dir and mntdir/.
> 
> Later, we could also use it to refer original tar blobs.
> 
> Signed-off-by: Jia Zhu <zhujia.zj@bytedance.com>
> Signed-off-by: Xin Yin <yinxin.x@bytedance.com>
> Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>

Acked-by: Chao Yu <chao@kernel.org>

Thanks,