Hello Ced,
On 11/12/23 8:01 PM, Cedric Blancher wrote:
On Fri, 10 Nov 2023 at 20:17, Chuck Lever III <chuck.lever@xxxxxxxxxx> wrote:
On Nov 10, 2023, at 3:30 AM, Martin Wege <martin.l.wege@xxxxxxxxx> wrote:
On Fri, Nov 10, 2023 at 3:20 AM Chuck Lever III <chuck.lever@xxxxxxxxxx> wrote:
On Nov 9, 2023, at 7:47 PM, Cedric Blancher <cedric.blancher@xxxxxxxxx> wrote:
On Fri, 10 Nov 2023 at 01:37, Chuck Lever III <chuck.lever@xxxxxxxxxx> wrote:
On Nov 9, 2023, at 7:05 PM, Cedric Blancher <cedric.blancher@xxxxxxxxx> wrote:
On Thu, 2 Nov 2023 at 10:51, Cedric Blancher <cedric.blancher@xxxxxxxxx> wrote:
Good morning!
Does anyone have examples of how to use the refer= option in /etc/exports?
Short answer:
To redirect an NFS mount from local machine /ref/baguette to
/export/home/baguette on host 134.49.22.111 add this to Linux
/etc/exports:
/ref *(no_root_squash,refer=/export/home@134.49.22.111)
This is basically an exports(5) manpage bug, which does not provide
ANY examples.
That's because setting up a referral this way is deprecated.
Why did you do that?
The nfsref command on Linux matches the same command on Solaris.
nfsref was added years ago to manage junctions, as part of FedFS.
The "refer=" export option can't do that...
Where in the kernel is the code for the refer= option? I'd like to get
some of my students to contribute support for custom NFS ports.
IIRC supporting ports is one thing we can't do right now because
the mountd downcall interface is text-based, and its parser can
barely handle "refer=", let alone specifying a port.
I had a chat this weekend with Roland Mainz (who works on the NFSv4
driver for Windows these days):
...
That is the old mistake to think that "hostname" and "port" are
separate entities. We had this kind of debate at SUN/MPK17 several
times. Host and TCP port are the "location of the server", and they
are inseparable.
...
The RFCs even help out with that one, for example RFC1738 (URL RFC)
defines a "hostport" in Page 18.
And that's what I actually did for ms-nfs41-client: NIH&Institute
Pasteur needed custom TCP server ports, and I implemented this by
changing the communication of nfs41_driver.sys (kernel) to userland
NFSv4 client daemon (nfsd_debug.exe) from "hostname" to "hostport",
and added the port number in the UNC, so Windows always uses (and
remembers!) the port number together with the hostname.
Or easier: I changed "hostname" to "hostport" to embed the port number
in the up-/downcalls for mount requests - and that is what the Linux
people can use too.
...
Our plan is to replace the mountd downcall with a netlink protocol
that Lorenzo is working on, and then it would be very straightforward
to add a port to each target location. But getting to a mature
netlink implementation will take a while.
Yeah, instead of waiting for NetLink you could implement Roland's
suggestion, and change "hostname" to "hostport" in your test-based
mount protocol, and technically everywhere else, like /proc/mounts and
the /sbin/mount output.
So instead of:
mount -t nfs -o port=4444 10.10.0.10:/backups /var/backups
you could use
mount -t nfs 10.10.0.10@4444:/backups /var/backups
The same applies to refer= - just change from "hostname" to
"hostport", and the text-based mountd downcall can stay the same (e.g.
so "foobarhost" changes to "foobarhost@444" in the mountd download.)
My suggestion is you and Roland attend the next Bakeathon, this
spring, which will have remote access for testing and
talk about this on one of @2pm talks.
steved.
