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Re: [Qemu-block] [PATCH v4 13/13] block/mirror: Block "device IO" during
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From: |
Paolo Bonzini |
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Subject: |
Re: [Qemu-block] [PATCH v4 13/13] block/mirror: Block "device IO" during mirror exit |
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Date: |
Tue, 19 May 2015 10:49:41 +0200 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 |
On 19/05/2015 18:48, Fam Zheng wrote:
>> >
>> > This is too late. As a rule, the blocker must be established before
>> > calling bdrv_drain, and removed on the next yield (in this case, before
>> > the assignment to last_pause_ns).
> I don't understand. If the blocker is removed before mirror_run returns,
> wouldn't more device IO already hit source image by the time mirror_exit runs?
If you go to mirror_exit, you won't reach the assignment (so you have to
remove the blocker in mirror_exit too).
But if you don't go to mirror_exit because cnt != 0, you must remove the
blocker before the next I/O.
Paolo
- [Qemu-block] [PATCH v4 08/13] blockdev: Block device IO during internal snapshot transaction, (continued)
- [Qemu-block] [PATCH v4 08/13] blockdev: Block device IO during internal snapshot transaction, Fam Zheng, 2015/05/18
- [Qemu-block] [PATCH v4 03/13] block-backend: Add blk_op_blocker_add_notifier, Fam Zheng, 2015/05/18
- [Qemu-block] [PATCH v4 09/13] blockdev: Block device IO during external snapshot transaction, Fam Zheng, 2015/05/18
- [Qemu-block] [PATCH v4 06/13] virtio-scsi-dataplane: Add "device IO" op blocker listener, Fam Zheng, 2015/05/18
- [Qemu-block] [PATCH v4 12/13] block: Block "device IO" during bdrv_drain and bdrv_drain_all, Fam Zheng, 2015/05/18
- [Qemu-block] [PATCH v4 01/13] block: Add op blocker type "device IO", Fam Zheng, 2015/05/18
- [Qemu-block] [PATCH v4 11/13] blockdev: Block device IO during blockdev-backup transaction, Fam Zheng, 2015/05/18
- [Qemu-block] [PATCH v4 13/13] block/mirror: Block "device IO" during mirror exit, Fam Zheng, 2015/05/18
[Qemu-block] [PATCH v4 10/13] blockdev: Block device IO during drive-backup transaction, Fam Zheng, 2015/05/18