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Re: [Qemu-devel] [sheepdog] [PATCH v4] sheepdog: fix loadvm operation
From: |
Liu Yuan |
Subject: |
Re: [Qemu-devel] [sheepdog] [PATCH v4] sheepdog: fix loadvm operation |
Date: |
Fri, 26 Apr 2013 17:04:06 +0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130329 Thunderbird/17.0.5 |
On 04/25/2013 09:06 PM, MORITA Kazutaka wrote:
> At Thu, 25 Apr 2013 20:49:39 +0800,
> Liu Yuan wrote:
>>
>> From: Liu Yuan <address@hidden>
>>
>> Currently the 'loadvm' opertaion works as following:
>> 1. switch to the snapshot
>> 2. mark current working VDI as a snapshot
>> 3. rely on sd_create_branch to create a new working VDI based on the snapshot
>>
>> This works not the same as other format as QCOW2. For e.g,
>>
>> qemu > savevm # get a live snapshot snap1
>> qemu > savevm # snap2
>> qemu > loadvm 1 # This will steally create snap3 of the working VDI
>>
>> Which will result in following snapshot chain:
>>
>> base <-- snap1 <-- snap2 <-- snap3
>> ^
>> |
>> working VDI
>>
>> snap3 was unnecessarily created and might be annoying users.
>>
>> This patch discard the unnecessary 'snap3' creation. and implement
>> rollback(loadvm) operation to the specified snapshot by
>> 1. switch to the snapshot
>> 2. delete working VDI
>> 3. rely on sd_create_branch to create a new working VDI based on the snapshot
>>
>> The snapshot chain for above example will be:
>>
>> base <-- snap1 <-- snap2
>> ^
>> |
>> working VDI
>>
>> Cc: address@hidden
>> Cc: MORITA Kazutaka <address@hidden>
>> Cc: Kevin Wolf <address@hidden>
>> Cc: Stefan Hajnoczi <address@hidden>
>> Signed-off-by: Liu Yuan <address@hidden>
>> ---
>> v4:
>> - print an error message when NO_VDI found
>>
>> v3:
>> - let boot from snapshot behave like 'loadvm'
>>
>> v2:
>> - use do_req() because sd_delete isn't in coroutine
>> - don't break old behavior if we boot up on the snapshot by using
>> s->reverted
>> to indicate if we delete working VDI successfully
>> - fix a subtle case that sd_create_branch() isn't called yet while another
>> 'loadvm' is executed
>>
>> block/sheepdog.c | 54
>> +++++++++++++++++++++++++++++++++++++++++++++++++++++-
>> 1 file changed, 53 insertions(+), 1 deletion(-)
>
> Reviewed-by: MORITA Kazutaka <address@hidden>
Missed this one, Stefan?
Thanks,
Yuan
- Re: [Qemu-devel] [PATCH v2] sheepdog: fix loadvm operation, (continued)
[Qemu-devel] [PATCH v4] sheepdog: fix loadvm operation, Liu Yuan, 2013/04/25
Re: [Qemu-devel] [PATCH v4] sheepdog: fix loadvm operation, Stefan Hajnoczi, 2013/04/26