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

[levin li]

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

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.

thanks,

levin