Re: [PATCH v3 0/3] io_uring getdents

[Dominique Martinet <asmadeus@codewreck.org>]

Jens Axboe wrote on Tue, Jul 11, 2023 at 05:51:46PM -0600:
> > So what filesystem actually uses this new NOWAIT functionality?
> > Unless I'm blind (quite possibly) I don't see any filesystem
> > implementation of this functionality in the patch series.

I had implemented this for kernfs and libfs (so sysfs, debugfs, possibly
tmpfs/proc?) in v2

The patch as of v2's mail has a bug, but my branch has it fixed as of
https://github.com/martinetd/linux/commits/io_uring_getdents

(I guess these aren't "real" enough though)

> > I know I posted a prototype for XFS to use it, and I expected that
> > it would become part of this patch series to avoid the "we don't add
> > unused code to the kernel" problem. i.e. the authors would take the
> > XFS prototype, make it work, add support into for the new io_uring
> > operation to fsstress in fstests and then use that to stress test
> > the new infrastructure before it gets merged....
> > 
> > But I don't see any of this?
> 
> That would indeed be great if we could get NOWAIT, that might finally
> convince me that it's worth plumbing up! Do you have a link to that
> prototype? That seems like what should be the base for this, and be an
> inspiration for other file systems to get efficient getdents via this
> (rather than io-wq punt, which I'm not a huge fan of...).

the xfs poc was in this mail:
https://lore.kernel.org/all/20230501071603.GE2155823@dread.disaster.area/

I never spent time debugging it, but it should definitely be workable

-- 
Dominique Martinet | Asmadeus