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Re: [Qemu-block] [Qemu-devel] [PATCH v4 00/27] block: Lock images when o
From: |
Daniel P. Berrange |
Subject: |
Re: [Qemu-block] [Qemu-devel] [PATCH v4 00/27] block: Lock images when opening |
Date: |
Tue, 10 May 2016 09:50:41 +0100 |
User-agent: |
Mutt/1.6.0 (2016-04-01) |
On Tue, May 10, 2016 at 09:43:04AM +0100, Richard W.M. Jones wrote:
> On Tue, May 10, 2016 at 09:14:26AM +0100, Richard W.M. Jones wrote:
> > However I didn't test the write-shareable case (the libvirt
> > <shareable/> flag which should map to a shared lock -- is that right Dan?).
>
> To Dan (mainly): I think setting the <shareable/> flag in libvirt only
> sets cache=unsafe on the qemu drive (it may have other effects for
> virtlockd). Should there be an extra qemu drive flag to communicate
> that the drive is write-shareable?
Sure, if QEMU had a way to indicate that the disk was used in a
write-sharable mode, libvirt would use it.
I agree with your general point that we should do no locking for
read-only access, F_RDLCK for shared-write and F_WRLCK for
exclusive-write access. I think I made that point similarly against
an earlier version of this patchset
Regards,
Daniel
--
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- [Qemu-block] [PATCH v4 19/27] qemu-iotests: 140: Disable image lock for qemu-io access, (continued)
- [Qemu-block] [PATCH v4 19/27] qemu-iotests: 140: Disable image lock for qemu-io access, Fam Zheng, 2016/05/09
- [Qemu-block] [PATCH v4 22/27] qemu-iotests: 030: Disable image lock when checking test image, Fam Zheng, 2016/05/09
- [Qemu-block] [PATCH v4 24/27] iotests: Disable image locking in 085, Fam Zheng, 2016/05/09
- [Qemu-block] [PATCH v4 21/27] qemu-iotests: Wait for QEMU processes before checking image in 091, Fam Zheng, 2016/05/09
- [Qemu-block] [PATCH v4 23/27] iotests: 087: Disable image lock in cases where file is shared, Fam Zheng, 2016/05/09
- [Qemu-block] [PATCH v4 26/27] block: Turn on image locking by default, Fam Zheng, 2016/05/09
- [Qemu-block] [PATCH v4 25/27] tests: Use null-co:// instead of /dev/null, Fam Zheng, 2016/05/09
- [Qemu-block] [PATCH v4 27/27] qemu-iotests: Add test case 153 for image locking, Fam Zheng, 2016/05/09
- Re: [Qemu-block] [PATCH v4 00/27] block: Lock images when opening, Richard W.M. Jones, 2016/05/10
- Re: [Qemu-block] [Qemu-devel] [PATCH v4 00/27] block: Lock images when opening, Richard W.M. Jones, 2016/05/10
- Re: [Qemu-block] [Qemu-devel] [PATCH v4 00/27] block: Lock images when opening,
Daniel P. Berrange <=
- Re: [Qemu-block] [Qemu-devel] [PATCH v4 00/27] block: Lock images when opening, Kevin Wolf, 2016/05/10
- Re: [Qemu-block] [Qemu-devel] [PATCH v4 00/27] block: Lock images when opening, Daniel P. Berrange, 2016/05/10
- Re: [Qemu-block] [Qemu-devel] [PATCH v4 00/27] block: Lock images when opening, Kevin Wolf, 2016/05/10
- Re: [Qemu-block] [Qemu-devel] [PATCH v4 00/27] block: Lock images when opening, Daniel P. Berrange, 2016/05/10
- Re: [Qemu-block] [Qemu-devel] [PATCH v4 00/27] block: Lock images when opening, Kevin Wolf, 2016/05/10
- Re: [Qemu-block] [Qemu-devel] [PATCH v4 00/27] block: Lock images when opening, Richard W.M. Jones, 2016/05/10
- Re: [Qemu-block] [Qemu-devel] [PATCH v4 00/27] block: Lock images when opening, Kevin Wolf, 2016/05/10
- Re: [Qemu-block] [Qemu-devel] [PATCH v4 00/27] block: Lock images when opening, Richard W.M. Jones, 2016/05/10
- Re: [Qemu-block] [Qemu-devel] [PATCH v4 00/27] block: Lock images when opening, Kevin Wolf, 2016/05/10
- Re: [Qemu-block] [Qemu-devel] [PATCH v4 00/27] block: Lock images when opening, Richard W.M. Jones, 2016/05/10