[sheepdog] [PATCH RFC] add support of sheepdog backing store

[Dan Mick]

>> Some might say this had better to be a dynamic loadable
>> library. Either is fine by me because it doesn't depend on any
>> original C header files.
>
> I'm ccing people who would be interested in modular backing
> stores, Ronnie Sahlberg and Andy Grover. I think the sheepdog backing
> store support doesn't have to be a module because it doesn't create
> any new dependencies. Any comments?

It seems that you've accomplished this by including structure and 
constant definitions (and presumably protocol-marshalling routines) in 
the tgt source file itself, which seems to me to be the wrong way to do 
it, but it does free you from requiring headers or libraries, so
technically speaking, true.

I wouldn't write the plugin this way (copying code), but that's me.