Re: [PATCH v2] Support for write stream IDs

[Christoph Hellwig <hch@infradead.org>]

On Tue, May 05, 2015 at 02:31:34PM -0600, Jens Axboe wrote:
> Even outside of that, there are use cases for caching that need not have
> hardware assist.

Could, would.  But in the meantime you'd adding dead wood kernel code,
and even worse user interfaces.

> >Merging infrastructure without any users is a
> >bad idea in general, and merging infrastructure with no user that
> >exposes untestable user interface and bloats core data structures is
> >even worse.  I don't think this has any merit at all at this point.
> 
> There is a user, we are using it. And there's no data structure bloating,
> both the file and inode additions are filling existing holes. I'll strongly
> disagree with your statement that it has no merit at all. In fact, the merit
> is quite clear.

Make sure everyone an get a nvme card from samsung supproting their
hack, and add it to the nvme driver keyed of a PCI ID check and we can
start talking about it.  We're not going to add hacks only a specific
big corporation can use.

Btw, the user interfacess really need man page additions and go past
linux-man and linux-api even in that case.