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From: Pekka Enberg <penberg@kernel.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Sasha Levin <levinsasha928@gmail.com>,
	kvm@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	Ingo Molnar <mingo@elte.hu>, Asias He <asias.hejun@gmail.com>,
	Cyrill Gorcunov <gorcunov@gmail.com>
Subject: Re: [PATCH] kvm tools: Use mmap for working with disk image V2
Date: Mon, 11 Apr 2011 21:49:41 +0300	[thread overview]
Message-ID: <BANLkTimOSWi5cA5i_6Zmoi3Q3bkZtZJgGQ@mail.gmail.com> (raw)
In-Reply-To: <20110411184102.GA5755@infradead.org>

On Mon, Apr 11, 2011 at 9:41 PM, Christoph Hellwig <hch@infradead.org> wrote:
> How do you plan to handle I/O errors or ENOSPC conditions?  Note that
> shared writeable mappings are by far the feature in the VM/FS code
> that is most error prone, including the impossiblity of doing sensible
> error handling.

Good point. I reverted the commit. Thanks!

On Mon, Apr 11, 2011 at 9:41 PM, Christoph Hellwig <hch@infradead.org> wrote:
> The version that accidentally used MAP_PRIVATE actually makes a lot of
> sense for an equivalent of qemu's snapshot mode where the image is
> readonly and changes are kept private as long as the amount of modified
> blocks is small enough to not kill the host VM, but using shared
> writeable mappings just sems dangerous.

Yup, Sasha, mind submitting a MAP_PRIVATE version that's enabled with
'--snapshot' (or equivalent) command line option.

                        Pekka
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      reply	other threads:[~2011-04-11 18:49 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1302351248-4853-1-git-send-email-levinsasha928@gmail.com>
2011-04-11 18:41 ` [PATCH] kvm tools: Use mmap for working with disk image V2 Christoph Hellwig
2011-04-11 18:49   ` Pekka Enberg [this message]

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