[PATCH v4 04/11] block: define meta io descriptor

[Anuj Gupta]

> Not sure what to do about the storage tag. For Linux that would probably
> be owned by the filesystem (as opposed to the application). But I guess
> one could envision a userland application acting as a storage target and
> in that case the tag would need to be passed to the kernel.

I will reserve space for storage tag in the user interface for now.
That way, we can introduce and use it later when it is actually used.

> 
> -- 
> Martin K. Petersen	Oracle Linux Engineering
>