Re: Here's One - NFS - Mounting Over Share = Nada

On 4/2/25 8:19 AM, Carlos E.R. wrote:

On 2025-04-02 13:39, c186282 wrote:

On 4/2/25 7:14 AM, Carlos E.R. wrote:

On 2025-04-02 12:49, vallor wrote:

On Tue, 1 Apr 2025 21:29:48 -0400, c186282 <c186282@nnada.net> wrote in
<UQ-dndQV6amaDnH6nZ2dnZfqnPednZ2d@giganews.com>:
>

Here's an interesting problem ....
>
I re-mount USB drives onto NFS share points. The problem is that NFS
doesn't SEE that - it only sees the previously empty dir instead.
Add a tag file to that dir and that's ALL you will see in the share on
another PC.
>
Tried variations of exportfs ... including the '-r' and '-au' then '-a'
AFTER doing the mount. Sorry, the clients can't see the mount. The NFS
stuff seems to cut in very early - before the USB re-mounts (done
@reboot). If you look on the host machine you DO see the USB drives, but
NEVER over the NFS share.
>
Why re-mount the USBs ? Because you can't always rely on Linux to mount
them in the same order, used to be even the same place.
'/media/<user>/whatever' seems hard-wired these days, but with multiple
USB drives you still can't count on drive 1 being the drive 1 in
/media/<user>. Kinda depends on which comes online first.
Naming the drives helps, but even then.
>
And no, symlinks to some other mount point don't work ... NFS just
shares a link to nowhere on the clients. 'hard' links ???
>
Have ONE share that's not a re-mounted anything - THAT always shows
perfectly on the clients. Weird thing, somehow, at one point I DID get
it to work - but not sure HOW. Just commented-out the old NFS and fstab
stuff, so I've been able to re-try, but now none work. Set everything to
775 or 777 for development work, but that doesn't help.
>
SAMBA - this sort of thing works fine, but I've had horrible probs with
SAMBA with the latest distros, ALWAYS intractable permissions issues no
matter the tweaks, hence using NFS.
>
So ... any insights on how to get NFS to "see" whatever IS mounted to
the share point AT THE MOMENT ???
>
Oh, latest MX Linux.

>
Take a look at "man exports" under the "nohide" option.

>
Ah, yes.
>
Last line says "not if you use NFSv4". The hiding doesn't happen with version 4.
>
Reminds me of something. How does one know what version is actually used?

>
>
   /var/libs/nfs/etab reads "NFS4"

 No such file here, not even the directory. It is "/var/lib/nfs/etab" here.
 But no, the version is not there:
 /data/hoard_1   

   You FIRST have to set up NFS and then edit /etc/exports and
   finally "exportfs -a". THEN the file will be in var/libs/nfs.
   That's what NFS really uses.

192.168.2.0/24(rw,sync,wdelay,hide,nocrossmnt,secure,no_root_squash,no_all_squash,subtree_check,secure_locks,acl,no_pnfs,fsid=10,anonuid=65534,anongid=65534,sec=sys,rw,secure,no_root_squash,no_all_squash)  

>
   But remounts to the shared dir still do
   not register.
>
   I'd LIKE NFS to reflect WHATEVER THE HELL I currently
   have mounted to that share dir.
>
   Or maybe it just CAN'T ??? There ARE reasons I stuck
   with SAMBA so long ... it (used to) Just Work.

  As I said, I restart the server. Or perhaps, "exportfs -r".

   Sorry, restarts do NOT work.
   It's kind of a TIMING problem.
   NFS seems to start up VERY early - and then fixates
   on whatever it finds. Re-mounts to the share dir
   come LATER and are NOT seen by NFS.

 Actually, I have a server machine with external disks, and they are just mounted and exported properly, no issues.
 Except that if the disk is not mounted, nfs doesn't start.

   Well, you got lucky.
   I'm not being so lucky.
   The share dirs DO exist, and NFS finds them, but
   NFS is not flexible about what's mounted there
   AT THE MOMENT.
   Being able to mount and re-mount and share
   whatever the hell is mounted NOW can be VERY
   useful and flexible. Should be SOME way to
   make NFS re-eval what's there. Been at this
   for days now and have 20 years of Linux
   experience - Slack and RH on FLOPPIES ...
   But I always figured NFS was ancient crap ...
   Anyway, today, I'm gonna try a HARD link to
   a 3rd dir where I can mount/re-mount as
   needed. Perhaps THAT link will work ?