Re: FreeBSD 16 nfsd: Unexpected NFS error 'NFS4ERR_NOFILEHANDLE' while probing named attr support

On Mon, 13 Apr 2026 at 01:06, Rick Macklem <[email protected]> wrote:
>
> On Sun, Apr 12, 2026 at 3:58 PM Dan Shelton <[email protected]> wrote:
> >
> > On Wed, 11 Mar 2026 at 01:13, Rick Macklem <[email protected]> wrote:
> > >
> > > On Tue, Mar 10, 2026 at 3:40 PM Dan Shelton <[email protected]> wrote:
> > > >
> > > > Hello,
> > > >
> > > > some odd issue with ms-nfs41-client: when connecting to a FreeBSD
> > > > 16.0-CURRENT main-n284403-895a97c875a0 (installed from
> > > > FreeBSD-16.0-CURRENT-amd64-20260224-16822dac32ab-284159-disc1.iso) NFS server:
> > > >
> > > > Windows side:
> > > > $ /sbin/nfs_mount -o rw 'F:' 'nfs://42.28.16.228//nfsdata'
> > > > Successfully mounted '42.28.16.228@NFS@2049' to drive 'F:'
> > > >
> > > > ms-nfs41-client prints this warning:
> > > > 204c: nfs41_superblock_getattr: Unexpected NFS error
> > > > 'NFS4ERR_NOFILEHANDLE' while probing named attr support
> > > > (the warning comes from
> > > > https://github.com/kofemann/ms-nfs41-client/blob/master/daemon/nfs41_ops.c#L1394)
> > > Hmm. The most obvious cause would be that the file system is not exported.
> > > Check the /etc/exports and, if you use the ZFS nfshare property,
> > > /etc/zfs/exports
> > > and make sure the file system is exported?
> > >
> > > As I've already mentioned, a packet capture is what I use to figure out
> > > what is going on. On the FreeBSD server..
> > > # tcpdump -s 0 -w out.pcap host <windows-client>
> > > - For a simple failure like the above, start it before doing the mount
> > >   and then kill it after the failure and send me "out.pcap".
> > >   (If there is going to be stuff in out.pcap that you need to keep
> > >    confidential, then you'll need to look at out.pcap yourself in wireshare.)
> >
> > We hit this bloody problem several times in February and March.
> > Workaround was to reboot until FILE_NAMED_STREAMS was reported.
> I'll admit I have no idea what you mean by this?

Windows API: https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-getvolumeinformationa

Windows sets the FILE_NAMED_STREAMS flag if a volume supports "Win32
named streams". msnfs41client implements Win32 named streams via NFS
named attr support. If the NFS server does not support NFS named
attrs, then the FILE_NAMED_STREAMS is not enabled, which breaks some
Windows applications.

Sometimes NFS named attrs are not detected. CAD/CAM customers want my
head because of this right now.

>
> >
> > What is the preferred tool to make a package capture on FreeBSD?
> (Assuming you meant packet capture..)

Yes, classic autocorrect fail. Welcome to the age of AI. Also the day
when my wife says I must not touch coffee.

>
> # tcpdump -s 0 -w out.pcap host <nfs-client-host>

Thank you

Dan
-- 
Dan Shelton - Cluster Specialist Win/Lin/Bsd