[Sheepdog] [PATCH v4 01/12] sheep: hide some minor store layout aware operations

[Christoph Hellwig]

On Wed, Dec 28, 2011 at 09:19:02PM +0800, Liu Yuan wrote:
> I am suspecting that only Simple Store will assume epoch/data layout, so
> I think we'd better put up with this ugliness, and see if there is a
> real need to abstract out this operation when new backend store is added
> later.

Doing conditionals based on a driver name in core code is a real
maintainance hurden over the long term as it breaks the abstraction.

I'd prefer the method call, but the other options would be to add a
flags field to the driver structure and then defined a flag for
the epoch/data layout which gets set by the simple driver.