[sheepdog] [PATCH v2 03/11] sheep: introduce generational reference counting for object reclaim

[MORITA Kazutaka]

At Mon, 1 Jul 2013 10:11:50 +0800,
Liu Yuan wrote:
> 
> > 
> > Basically the old format can be still usable, but the existing objects
> > can be reclaimed wrongly since the old inode doesn't contain correct
> > reference counts.  In the next version, I think of adding a check to
> > avoid this problem and a command to update the object reference counts
> > for the existing users.
> > 
> 
> then QEMU driver need update and old QEMU can't work with new sheep?

It can work.  The old QEMU causes two additional writes for each CoW,
but the update QEMU does only one write.

Thanks,

Kazutaka