[sheepdog] [PATCH 1/2] collie: add command 'collie vdi rollback'

[levin li]

On 08/31/2012 02:38 PM, MORITA Kazutaka wrote:
> At Fri, 31 Aug 2012 14:25:04 +0800,
> levin li wrote:
>>
>> On 08/31/2012 02:10 PM, MORITA Kazutaka wrote:
>>> At Fri, 31 Aug 2012 13:53:29 +0800,
>>> levin li wrote:
>>>>
>>>> On 08/31/2012 12:17 PM, MORITA Kazutaka wrote:
>>>>> At Thu, 30 Aug 2012 13:59:54 +0800,
>>>>> levin li wrote:
>>>>>>
>>>>>> From: levin li <xingke.lwp at taobao.com>
>>>>>>
>>>>>> With this command we can rollback a cloned VDI to any specified
>>>>>> snapshot, or easily reset to its parent VDI, the usage is easy.
>>>>>>
>>>>>> To rollback to a specified snapshot:
>>>>>>
>>>>>> $ collie vdi rollback -s 1 base_vdi clone_vdi
>>>>>
>>>>> Do we need to go back to a snapshot of another vdi?
>>>>>
>>>>> What I thought was like follows:
>>>>>
>>>>>   $ collie vdi rollback -h
>>>>>   Usage: collie vdi check [-s snapshot] <vdiname>
>>>>>
>>>>>   $ collie vdi create test 4G
>>>>>   $ collie vdi snapshot test -s snap1
>>>>>   $ collie vdi snapshot test -s snap2
>>>>>   $ collie vdi tree test
>>>>>   test---[2012-08-31 13:05]---[2012-08-31 13:06]---(you are here)
>>>>>   $ collie vdi list test
>>>>>     Name        Id    Size    Used  Shared    Creation time   VDI id  Copies  Tag
>>>>>   s test         1  4.0 GB  0.0 MB  0.0 MB 2012-08-31 13:05   7c2b25     1         snap1
>>>>>   s test         2  4.0 GB  0.0 MB  0.0 MB 2012-08-31 13:06   7c2b26     1         snap2
>>>>>     test         3  4.0 GB  0.0 MB  0.0 MB 2012-08-31 13:07   7c2b27     1              
>>>>>
>>>>>   $ collie vdi rollback test -s snap1
>>>>>   $ collie vdi tree test
>>>>>   test---[2012-08-31 13:05]-+-[2012-08-31 13:06]---[2012-08-31 13:07]
>>>>>                             `-(you are here)
>>>>>   $ collie vdi list test
>>>>>     Name        Id    Size    Used  Shared    Creation time   VDI id  Copies  Tag
>>>>>   s test         1  4.0 GB  0.0 MB  0.0 MB 2012-08-31 13:05   7c2b25     1         snap1
>>>>>   s test         2  4.0 GB  0.0 MB  0.0 MB 2012-08-31 13:06   7c2b26     1         snap2
>>>>>   s test         3  4.0 GB  0.0 MB  0.0 MB 2012-08-31 13:07   7c2b27     1              
>>>>>     test         4  4.0 GB  4.0 MB  0.0 MB 2012-08-31 13:08   7c2b28     1              
>>>>>
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Kazutaka
>>>>>
>>>>
>>>> Maybe I misunderstood you, but this patch can do more than you expected,
>>>> it's no harm for users to rollback a VDI to any snapshot if they choose to.
>>>
>>> I've tried, but it doesn't work well.
>>>
>>> $ collie vdi create test 4G
>>> $ collie vdi snapshot test -s snap1
>>> $ collie vdi snapshot test -s snap2
>>> $ collie vdi rollback test -s snap1  <- Can you support this usage?
>>> Segmentation fault                   <- Please fix this
>>> $ collie vdi rollback test test -s snap1
>>> Can not rollback a non-cloned VDI    <- We want to a rollback command even if
>>>                                         the vdi is not a cloned one
>>>
>>> Thanks,
>>>
>>> Kazutaka
>>>
>>
>> I'll fix the segment fault, but it doesn't support the usage like this:
>>
>> $ collie vdi rollback test -s snap1

Well, I must make one thing clear, what do you mean by this command,
you want to rollback which VDI to which snapshot ? I think the usage
is confusing.

thanks,

levin

> 
> Please support it.  This is the usage most users would imagine, I
> think.
> 
>>
>> We must specify the dest name.
>>
>> I make it only handle the rollback for cloned VDI now, how can we rollback
>> a snapshot? it may destroys the VDI tree structure.
> 
> Adding a new child to the snapshot like creating a clone does not
> work?
> 
> Thanks,
> 
> Kazutaka
>