On Mon, 2020-11-30 at 18:11 -0500, Chuck Lever wrote: > > > > On Nov 30, 2020, at 4:24 PM, trondmy@xxxxxxxxxx wrote: > > > > From: Jeff Layton <jeff.layton@xxxxxxxxxxxxxxx> > > > > With NFSv3 nfsd will always attempt to send along WCC data to the > > client. This generally involves saving off the in-core inode > > information > > prior to doing the operation on the given filehandle, and then > > issuing a > > vfs_getattr to it after the op. > > > > Some filesystems (particularly clustered or networked ones) have an > > expensive ->getattr inode operation. Atomicitiy is also often > > difficult > > or impossible to guarantee on such filesystems. For those, we're > > best > > off not trying to provide WCC information to the client at all, and > > to > > simply allow it to poll for that information as needed with a > > GETATTR > > RPC. > > > > This patch adds a new flags field to struct export_operations, and > > defines a new EXPORT_OP_NOWCC flag that filesystems can use to > > indicate > > that nfsd should not attempt to provide WCC info in NFSv3 replies. > > It > > also adds a blurb about the new flags field and flag to the > > exporting > > documentation. > > > > The server will also now skip collecting this information for NFSv2 > > as > > well, since that info is never used there anyway. > > > > Note that this patch does not add this flag to any filesystem > > export_operations structures. This was originally developed to > > allow > > reexporting nfs via nfsd. That code is not (and may never be) > > suitable > > for merging into mainline. > > > > Other filesystems may want to consider enabling this flag too. It's > > hard > > to tell however which ones have export operations to enable export > > via > > knfsd and which ones mostly rely on them for open-by-filehandle > > support, > > so I'm leaving that up to the individual maintainers to decide. I > > am > > cc'ing the relevant lists for those filesystems that I think may > > want to > > consider adding this though. > > > > Cc: HPDD-discuss@xxxxxxxxxxxx > > Cc: ceph-devel@xxxxxxxxxxxxxxx > > Cc: cluster-devel@xxxxxxxxxx > > Cc: fuse-devel@xxxxxxxxxxxxxxxxxxxxx > > Cc: ocfs2-devel@xxxxxxxxxxxxxx > > Signed-off-by: Jeff Layton <jeff.layton@xxxxxxxxxxxxxxx> > > Signed-off-by: Lance Shelton <lance.shelton@xxxxxxxxxxxxxxx> > > Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> > > These seem to apply fine, thanks for resending. > > If you post a v3 to address Bruce's comment, can you also > address this checkpatch nit? I'm not seeing how I can address Bruce's comment at this time. I can send you a v3 that changes the comment to the "fallthrough" obscenity. > > > WARNING: Prefer 'fallthrough;' over fallthrough comment > #154: FILE: fs/nfsd/nfsfh.c:299: > + /* Fallthrough */ > > total: 0 errors, 1 warnings, 120 lines checked > > NOTE: For some of the reported defects, checkpatch may be able to > mechanically convert to the typical style using --fix or --fix- > inplace. > -- Trond Myklebust Linux NFS client maintainer, Hammerspace trond.myklebust@xxxxxxxxxxxxxxx
