Linux-Block Archive on lore.kernel.org
 help / color / Atom feed
From: Manuel Bentele <manuel-bentele@web.de>
To: Roman Penyaev <rpenyaev@suse.de>
Cc: Hannes Reinecke <hare@suse.de>,
	linux-block@vger.kernel.org, linux-block-owner@vger.kernel.org
Subject: Re: Adding QCOW2 reading/writing support
Date: Mon, 20 May 2019 15:05:56 +0200
Message-ID: <cee07f0a-59c8-3ee9-bcaa-8b38f1de2756@web.de> (raw)
In-Reply-To: <7a74dd35a390df25f2874aa7b4f8547e@suse.de>

Hi,

On 5/14/19 4:28 PM, Roman Penyaev wrote:
> On 2019-04-17 23:53, Manuel Bentele wrote:
>
> [cut]
>
>> If you have an idea to solve the opposition for file formats that are
>> acting as a container or virtual disk node for various data, please let
>> me know.
>
> If you need a raw block device you can export qcow2 image as a network
> block
> device, something as the following:
>
> # modprobe nbd
> # qemu-nbd --connect=/dev/nbd0 image.qcow2
> # fdisk -l /dev/nbd0
>
> I suppose simplest variant.
>
> --
> Roman

Thanks for your suggestion. We already discussed this during a project
meeting. Some time ago, I have summarized that already (sorry for the
diverging conversation of this topic on the mailinglist).
All in all, the crucial point is the performance:

> [...]
>
> A workaround for that problem could be the local usage of nbd to include
> the QCOW2 disk image as block device, but it involves a lot of
> interaction between user and kernel space and thus an decreasing
> performance. That leads to the motivation to implement the reading of
> QCOW2 disk images directly in the kernel and aim for an merge into the
> mainline kernel source to avoid out-of-kernel-tree maintenance.
>
> [...]

--
Manuel

      reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-16 21:30 Manuel Bentele
2019-04-17  1:35 ` Ming Lei
2019-04-17 11:32   ` Manuel Bentele
2019-04-17 12:16     ` Hannes Reinecke
2019-04-17 21:04       ` Manuel Bentele
2019-04-18  1:05         ` Ming Lei
2019-04-18 10:02           ` Manuel Bentele
2019-05-14  8:56             ` Manuel Bentele
2019-04-17 11:58 ` Hannes Reinecke
2019-04-17 21:53   ` Manuel Bentele
2019-05-14 14:28     ` Roman Penyaev
2019-05-20 13:05       ` Manuel Bentele [this message]

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=cee07f0a-59c8-3ee9-bcaa-8b38f1de2756@web.de \
    --to=manuel-bentele@web.de \
    --cc=hare@suse.de \
    --cc=linux-block-owner@vger.kernel.org \
    --cc=linux-block@vger.kernel.org \
    --cc=rpenyaev@suse.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-Block Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-block/0 linux-block/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-block linux-block/ https://lore.kernel.org/linux-block \
		linux-block@vger.kernel.org linux-block@archiver.kernel.org
	public-inbox-index linux-block


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-block


AGPL code for this site: git clone https://public-inbox.org/ public-inbox