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Re: [Qemu-block] [PATCH v11 01/19] block: Add bdrv_drain_all_{begin, end
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-block] [PATCH v11 01/19] block: Add bdrv_drain_all_{begin, end}() |
Date: |
Tue, 25 Oct 2016 15:53:00 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 |
On 25/10/2016 15:39, Alberto Garcia wrote:
> On Mon 24 Oct 2016 12:53:41 PM CEST, Paolo Bonzini wrote:
>
>>> My first thoughts were about how to let an unpause succeed without a
>>> previous pause for these objects, but actually I think this isn't
>>> what we should do. We rather want to actually do the pause instead
>>> because even new BDSes and block jobs should probably start in a
>>> quiesced state when created inside a drain_all section.
>>
>> Yes, I agree with this. It shouldn't be too hard to implement it. It
>> would require a BlockDriverState to look at the global "inside
>> bdrv_drain_all_begin" state, and ask its BlockBackend to disable
>> itself upon bdrv_replace_child.
>
> Why in bdrv_replace_child()? bdrv_drain_all_end() enables all BDSs, but
> if you add one with "blockdev-add" it's not going to be disabled using
> this method.
You only need to disable it when blk_insert_bs is called. In fact...
> In addition to that block jobs need the same, don't they? Something like
> "job->pause_count = all_quiesce_counter" in the initialization.
... we discussed a couple weeks ago that block jobs should register
BlkDeviceOps that pause the job in the drained_begin callback. So when
the block job calls blk_insert_bs, the drained_begin callback would
start the job as paused.
> I think we'd also need to add block_job_pause_point() at the beginning
> of each one of their coroutines, in order to make sure that they really
> start paused.
It depends on the job, for example streaming starts with
block_job_sleep_ns. Commit also does, except for some blk_getlength and
blk_truncate calls that could be moved to the caller.
Paolo
- [Qemu-block] [PATCH v11 01/19] block: Add bdrv_drain_all_{begin, end}(), (continued)
- [Qemu-block] [PATCH v11 01/19] block: Add bdrv_drain_all_{begin, end}(), Alberto Garcia, 2016/10/14
- Re: [Qemu-block] [PATCH v11 01/19] block: Add bdrv_drain_all_{begin, end}(), Paolo Bonzini, 2016/10/15
- Re: [Qemu-block] [PATCH v11 01/19] block: Add bdrv_drain_all_{begin, end}(), Kevin Wolf, 2016/10/19
- Re: [Qemu-block] [PATCH v11 01/19] block: Add bdrv_drain_all_{begin, end}(), Alberto Garcia, 2016/10/20
- Re: [Qemu-block] [PATCH v11 01/19] block: Add bdrv_drain_all_{begin, end}(), Kevin Wolf, 2016/10/20
- Re: [Qemu-block] [PATCH v11 01/19] block: Add bdrv_drain_all_{begin, end}(), John Snow, 2016/10/21
- Re: [Qemu-block] [PATCH v11 01/19] block: Add bdrv_drain_all_{begin, end}(), Alberto Garcia, 2016/10/21
- Re: [Qemu-block] [Qemu-devel] [PATCH v11 01/19] block: Add bdrv_drain_all_{begin, end}(), John Snow, 2016/10/21
- Re: [Qemu-block] [PATCH v11 01/19] block: Add bdrv_drain_all_{begin, end}(), Paolo Bonzini, 2016/10/24
- Re: [Qemu-block] [PATCH v11 01/19] block: Add bdrv_drain_all_{begin, end}(), Alberto Garcia, 2016/10/25
- Re: [Qemu-block] [PATCH v11 01/19] block: Add bdrv_drain_all_{begin, end}(),
Paolo Bonzini <=
- Re: [Qemu-block] [PATCH v11 01/19] block: Add bdrv_drain_all_{begin, end}(), Kevin Wolf, 2016/10/25
- Re: [Qemu-block] [PATCH v11 01/19] block: Add bdrv_drain_all_{begin, end}(), Paolo Bonzini, 2016/10/25
- Re: [Qemu-block] [PATCH v11 01/19] block: Add bdrv_drain_all_{begin, end}(), Kevin Wolf, 2016/10/25
- Re: [Qemu-block] [PATCH v11 01/19] block: Add bdrv_drain_all_{begin, end}(), Alberto Garcia, 2016/10/25
- Re: [Qemu-block] [PATCH v11 01/19] block: Add bdrv_drain_all_{begin, end}(), Paolo Bonzini, 2016/10/25
[Qemu-block] [PATCH v11 12/19] qemu-iotests: Test streaming to an intermediate layer, Alberto Garcia, 2016/10/14
[Qemu-block] [PATCH v11 19/19] qemu-iotests: Test the 'base-node' parameter of 'block-stream', Alberto Garcia, 2016/10/14
[Qemu-block] [PATCH v11 18/19] block: Add 'base-node' parameter to the 'block-stream' command, Alberto Garcia, 2016/10/14
[Qemu-block] [PATCH v11 08/19] block: Block all intermediate nodes in commit_active_start(), Alberto Garcia, 2016/10/14
[Qemu-block] [PATCH v11 14/19] qemu-iotests: Test overlapping stream and commit operations, Alberto Garcia, 2016/10/14