On 7/4/25 3:46 PM, Mike Snitzer wrote: > On Mon, Jun 30, 2025 at 10:50:42AM -0400, Chuck Lever wrote: >> On 6/19/25 4:19 PM, Mike Snitzer wrote: >>> On Tue, Jun 17, 2025 at 01:31:23PM -0400, Chuck Lever wrote: >>>> >>>> If we were to make all NFS READ operations use O_DIRECT, then of course >>>> NFSD's splice read should be removed at that point. >>> >>> Yes, that makes sense. I still need to try Christoph's idea (hope to >>> do so over next 24hrs): >>> https://lore.kernel.org/linux-nfs/aEu3o9imaQQF9vyg@xxxxxxxxxxxxx/ >>> >>> But for now, here is my latest NFSD O_DIRECT/DONTCACHE work, think of >>> the top 6 commits as a preview of what'll be v2 of this series: >>> https://git.kernel.org/pub/scm/linux/kernel/git/snitzer/linux.git/log/?h=kernel-6.12.24/nfsd-testing >> >> I was waiting for a series repost, but in the meantime... >> >> The one thing that caught my eye was the relocation of fh_getattr(). >> >> - If fh_getattr() is to be moved to fs/nfsd/vfs.c, then it should be >> renamed nfsd_getattr() (or similar) to match the API naming >> convention in that file. >> >> - If fh_getattr() is to keep its current name, then it should be >> moved to where the other fh_yada() functions reside, in >> fs/nfsd/nfsfh.c >> >> In a private tree, I constructed a patch to do the latter. I can >> post that for comment. > > Hi, > > Sure, I can clean it up to take your patch into account. Please share > your patch (either pointer to commit in a branch or via email). > > Tangent to explain why I've fallen off the face of the earth: > I have just been focused on trying to get client-side misaligned > O_DIRECT READ IO to be expanded to be DIO-aligned like I did with > NFSD. Turns out it is quite involved (took a week of focused > development to arrive at the fact that NFS client's nfs_page and > pagelist code's use of memory as an array is entirely incompatiable. > Discussed with Trond and the way forward would require having NFS > client fill in xdr_buf's bvec and manage manually.. but that's a > serious hack. Better long term goal is to convert xdr_buf over to > using bio_vec like NFSD is using. > > So rather than do any of that _now_, I just today implemented an NFS > LOCALIO fallback to issuing the misaligned DIO READ using remote call > to NFSD (able to do so on a per-IO basis if READ is misaligned). > Seems to work really well, but does force LOCALIO to go remote (over > loopback network) just so it can leverage our new NFSD mode to use > O_DIRECT and expand misaligned writes, which is enabled with: > echo 2 > /sys/kernel/debug/nfsd/io_cache_read > > All said, I'll get everything cleaned up and send out v2 of this > patchset on Monday. (If you share your patch I can rebase ontop of it > and hopefully still get v2 out on Monday) https://lore.kernel.org/linux-nfs/20250702233345.1128154-1-cel@xxxxxxxxxx/T/#t But no-one has yet offered an opinion about whether to rename fh_getattr or move it to fs/nfsd/nfsfh.c. Things might change. -- Chuck Lever
