On Tue, 2026-01-20 at 09:12 -0500, Jeff Layton wrote: > On Tue, 2026-01-20 at 08:20 -0500, Jeff Layton wrote: > > On Mon, 2026-01-19 at 23:44 -0800, Christoph Hellwig wrote: > > > On Mon, Jan 19, 2026 at 11:26:18AM -0500, Jeff Layton wrote: > > > > + EXPORT_OP_NOLOCKS - Disable file locking on this filesystem. Some > > > > + filesystems cannot properly support file locking as implemented by > > > > + nfsd. A case in point is reexport of NFS itself, which can't be > > > > done > > > > + safely without coordinating the grace period handling. Other > > > > clustered > > > > + and networked filesystems can be problematic here as well. > > > > > > I'm not sure this is very useful. It really needs to document what > > > locking semantics nfs expects, because otherwise no reader will know > > > if they set this or not. > > > > Fair point. I'll see if I can draft something better. Suggestions > > welcome. > > How about this? > > + EXPORT_OP_NOLOCKS - Disable file locking on this filesystem. Filesystems > + that want to support locking over NFS must support POSIX file locking > + semantics and must handle lock recovery requests from clients after a > + reboot. Most local disk, RAM, or pseudo-filesystems use the generic POSIX > + locking support in the kernel and naturally provide this capability. > Network > + or clustered filesystems usually need special handling to do this > properly.
Even better, I think? + + EXPORT_OP_NOLOCKS - Disable file locking on this filesystem. Filesystems + that want to support locking over NFS must support POSIX file locking + semantics. When the server reboots, the clients will issue requests to + recover their locks, which nfsd will issue to the filesystem as new lock + requests. Those must succeed in order for lock recovery to work. Most + local disk, RAM, or pseudo-filesystems use the generic POSIX locking + support in the kernel and naturally provide this capability. Network or + clustered filesystems usually need special handling to do this properly. + Set this flag on filesystems that can't guarantee the proper semantics + (e.g. reexported NFS). -- Jeff Layton <[email protected]>
