> On Dec 1, 2024, at 8:28 AM, Jeff Layton <jlayton@xxxxxxxxxx> wrote: > > On Sun, 2024-12-01 at 14:12 +0100, Christian Brauner wrote: >> Hey, >> >> Some filesystems like kernfs and pidfs support file handles as a >> convenience to enable the use of name_to_handle_at(2) and >> open_by_handle_at(2) but don't want to and cannot be reliably exported. >> Add a flag that allows them to mark their export operations accordingly >> and make NFS check for its presence. >> >> @Amir, I'll reorder the patches such that this series comes prior to the >> pidfs file handle series. Doing it that way will mean that there's never >> a state where pidfs supports file handles while also being exportable. >> It's probably not a big deal but it's definitely cleaner. It also means >> the last patch in this series to mark pidfs as non-exportable can be >> dropped. Instead pidfs export operations will be marked as >> non-exportable in the patch that they are added in. >> >> Thanks! >> Christian >> >> --- >> Christian Brauner (4): >> exportfs: add flag to indicate local file handles >> kernfs: restrict to local file handles >> ovl: restrict to exportable file handles >> pidfs: restrict to local file handles >> >> fs/kernfs/mount.c | 1 + >> fs/nfsd/export.c | 8 +++++++- >> fs/overlayfs/util.c | 7 ++++++- >> fs/pidfs.c | 1 + >> include/linux/exportfs.h | 1 + >> 5 files changed, 16 insertions(+), 2 deletions(-) >> --- >> base-commit: 74e20c5946ab3f8ad959ea34f63f21e157d3ebae >> change-id: 20241201-work-exportfs-cd49bee773c5 >> > > I've been following the pidfs filehandle discussion and this is exactly > what I was thinking we needed: a way to explicitly label certain > fstypes as unexportable via nfsd. > > Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx> > Acked-by: Chuck Lever <chuck.lever@xxxxxxxxxx <mailto:chuck.lever@xxxxxxxxxx>> Though, I wonder if a similar but separate prohibition mechanism might be necessary for other in-kernel network file system server implementations (eg, ksmbd). -- Chuck Lever
