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

[MORITA Kazutaka]

At Fri, 31 Aug 2012 14:59:43 +0800,
levin li wrote:
> 
> 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.

From the current vdi to the specified snapshot.

My example doesn't help you?

>   $ 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