On Fri, Feb 08, 2019 at 09:46:12AM +0100, Christoph Hellwig wrote: > On Thu, Feb 07, 2019 at 02:25:01PM -0700, Andreas Dilger wrote: > > Do we really need to be this way, about reserving a single flag for Lustre, > > which will likely also be useful for other filesystems? It's not like > > Lustre is some closed-source binary module for which we need to make life > > difficult, it is used by many thousands of the largest computers at labs > > and universities and companies around the world. We are working to clean > > up the code outside the staging tree and resubmit it. Not reserving a flag > > just means we will continue to use random values in Lustre before it can > > be merged, which will make life harder when we try to merge again. > > No, it is available in source, but otherwise just as bad. And we generally > only define APIs for in-kernel usage. > > If we can come up with a good API for in-kernel filesystems we can do > that, otherwise hell no. And staging for that matter qualifies as out > of tree. > > That being said I'm really worried about these FIEMAP extensions as > userspace has no business poking into details of the placement (vs > just the layout). > I tend to say that identifying on which device an extent is is better than simply saying 'it maps to physical blocks X-Z, but it's your problem to identify which device X-Z belongs to'. > But all that belongs into a separate dicussion instead of dragging down > this series where it does not belong at all. Agreed, but now I'm on a kind of dead-end :P Darrick's concerns are valid, regarding letting currently unsupported filesystems to suddenly allow FIBMAP calls, but on the other hand, his proposed solution, which is also valid, requires a new discussion/patchset to discuss an improvement of the FIEMAP infra-structure, and 'fix' the problem mentioned. Using a flag to identify FIBMAP calls has been rejected. So, I'd accept suggestions on how to move this patch forward, without requiring the improvements suggested by Darrick, and, without using a flag to tag FIBMAP calls, as suggested by me, I'm kind of running out of ideas by now :( Cheers -- Carlos
