From: Paolo Bonzini <pbonzini@redhat.com>
To: Chen HanXiao <chenhanxiao@cn.fujitsu.com>
Cc: 'Christoph Hellwig' <hch@lst.de>, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] Use SCSI command to get size of SG device
Date: Wed, 10 Oct 2012 11:01:31 +0200 [thread overview]
Message-ID: <5075396B.2060302@redhat.com> (raw)
In-Reply-To: <006501cda6c1$e080f8a0$a182e9e0$@cn.fujitsu.com>
Il 10/10/2012 10:33, Chen HanXiao ha scritto:
>> You need to use scsi-block instead of scsi-generic. However, I don't see
>> how this can work. After the snapshot, the image will be qcow2, not raw, and
>> thus it will not support bdrv_aio_ioctl. Hence any SCSI command (for
>> scsi-generic) or any non-data SCSI command (for scsi-block) will fail.
>
> That's the issue what I also encountered.
> Do you mean that it is impossible for us to enable snapshot for
> scsi-generic?
It's impossible, and rightly so: the user could anyway bypass the
snapshotting and write to the disk (WRITE SAME for example).
Not just snapshot=on, which fails because it is early enough that the
disk fails to initialize. Live snapshots also ought to be blocked, it
is a bug that they are not.
Paolo
prev parent reply other threads:[~2012-10-10 9:01 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-09 9:42 [Qemu-devel] [PATCH] Use SCSI command to get size of SG device Chen HanXiao
2012-10-09 17:21 ` Christoph Hellwig
2012-10-10 2:11 ` Chen HanXiao
2012-10-10 6:33 ` Paolo Bonzini
2012-10-10 8:33 ` Chen HanXiao
2012-10-10 9:01 ` Paolo Bonzini [this message]
Reply instructions:
You may reply publicly 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=5075396B.2060302@redhat.com \
--to=pbonzini@redhat.com \
--cc=chenhanxiao@cn.fujitsu.com \
--cc=hch@lst.de \
--cc=qemu-devel@nongnu.org \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.