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

[MORITA Kazutaka]

At Fri, 31 Aug 2012 12:25:45 +0800,
Liu Yuan wrote:
> 
> On 08/31/2012 12:17 PM, MORITA Kazutaka wrote:
> >   $ 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  
> 
> Why rollback create another vdi? I thought of rollback in place instead
> of creating another VDI object too.

If we don't delete newer snapshots than the rollbacked one (this
behavior is same as VMware and VirtualBox), adding a child vdi to the
snapshot looks the easiest way to implement the operation.

Thanks,

Kazutaka