[SOLVED] Mount NFS share from Linux to QNAP NAS

mackowiakp · 12-21-2019, 12:04 PM

I use such command to mount NFS share exported from Linux server (Mageia 7 based, 64 bit, 6 core/12 treads, 64 GB RAM) to QNAL NAS (64 bit Intel, 8 GB RAM)

Mount command executed on QNAP:

Code:

mount -w -vvv -t nfs -o rw -o vers=3 -O user=root.password=<pass> 192.168.0.2:/home/maciek/back/RSYNC /share/CACHEDEV2_DATA/mnt

It mounts RSYNC dir from PC to /share/CACHEDEV2_DATA/mnt without problems.
/home/maciek/back/RSYNC is de facto separate filesystem mounted on demand from USB ver 3 connected v3 HDD. The content of /share/CACHEDEV2_DATA/mnt listed on QNAP after mount looks like this:

Code:

[/share/homes/media/Pobrane] # ls -la /share/CACHEDEV2_DATA/mnt/
total 100
drwxrwxrwx 23 admin administrators  4096 2019-12-21 12:50 ./
drwxrwxrwx  6 admin administrators  4096 2019-03-23 09:21 ../
drwxr-xr-x  2 admin administrators  4096 2017-08-26 10:01 Asus/
drwxr-xr-x  3 media media           4096 2019-01-03 07:27 Bioama/
drwxr-xr-x  3 admin administrators  4096 2019-05-16 16:25 Domoticz/
drwxr-xr-x  3 admin administrators  4096 2017-03-17 13:57 Entware/
drwxr-xr--  4 media media           4096 2014-03-07 19:50 EXATEL/
drwxrwxr-x 27 media media           4096 2019-02-26 14:04 Filmy/
drwxrwxr-x  2 media media           4096 2019-12-20 16:47 Gosia_ISO/
drwxr-xr-x 12 admin administrators  4096 2018-08-17 13:10 jffs/
drwxr-xr-x  3 media media           4096 2016-08-05 05:31 LAMIA/
drwx------  8 media media           4096 2014-03-07 10:56 lost+found/
drwxr-xr-x  3 media media           4096 2019-01-03 07:27 Media/
drwxrwxr-x 57 media media           4096 2019-02-26 14:04 Muzyka/
drwxrwxr-x  3 admin administrators  4096 2019-12-18 16:16 NextCloud/
drwxr-xr-x  9 media media           4096 2017-08-17 14:54 Oprogramowanie-Gosia/
drwxrwxr--  6 media media           4096 2015-12-08 07:53 Oprogramowanie-Piotr/
drwxr-xr-x  9 media media           4096 2018-11-09 10:25 Oprogramowanie-Piotr-L/
drwxr-xr-x  2 media media           4096 2019-12-20 16:40 Piotr_ISO/
drwxrwxr-x  2 media media           4096 2019-12-20 16:44 Piotr-L_ISO/
drwxr-xr-x  5 media media          12288 2015-02-08 19:21 PROKOM/
lrwxrwxrwx  1 admin administrators    27 2017-03-08 14:18 @Recycle -> /share/homes/@Recycle/media
drwxr-xr-x  2 media media           4096 2014-03-24 17:57 Stara poczta/
drwxrwxr-x 38 media media           4096 2019-09-13 10:51 Zdjecia/

Looks ok. But it is possible to create/modify/delete file in root exported dir that is /share/CACHEDEV2_DATA/mnt/ directory but not in any subdirectory. For example:

Code:

[/share/homes/media/Pobrane] # touch /share/CACHEDEV2_DATA/mnt/jffs/ttt
touch: /share/CACHEDEV2_DATA/mnt/jffs/ttt: Permission denied

So what I am doing wrong?

The content of /etc/exports on PC:

Code:

[root@Piotr ~]# cat /etc/exports
/home/maciek/back/RSYNC 192.168.0.7(rw,subtree_check,crossmnt)

On both units are users having the same UID/GID, but different names.

Any idea?

berndbausch · 12-21-2019, 04:30 PM

You seem to be root on the NFS client. Normally, root is mapped to a non-root user. Check export option no_root_squash.

mackowiakp · 12-21-2019, 11:07 PM

Yes, I am root. But in QNAP they use name "admin" as user with UID=0 and administrator as GID=0. So admin/administrator stands for root/root. Strange, but QNAP OS is bizarre version of Debian/Ubuntu 14.4

EDIT

Adding no_root_squash to exports resolved problem THX !

But now I have another problem. If I unmount NFS share and than try to mount it again, sometimes error
"Stale file handle" occurs. It seams to say that NFS share was not unmount fully clean and something still try to access unmounted NFS share. If only my assumption but it looks like that.
Any advice what to do wit this without rebooting both client and server?

berndbausch · 12-22-2019, 04:10 AM

I googled this for you (and for me). Plenty of information about this error is available. One of the better resources is https://unix.stackexchange.com/quest...cannot-umount; the second answer provides steps to get rid of the problem.

EDIT: The superuser is UID 0. It's normally named root, but can have other names. Thus, QNAP's admin may be an unusual name, but it's entirely legitimate. The "root" in "no_root_squash" doesn't actually refer to user root, but to UID 0.
As far as I know, anyway.

mackowiakp · 12-22-2019, 05:04 AM

Quote:

The "root" in "no_root_squash" doesn't actually refer to user root, but to UID 0.

Yes, of course I know.

THX for help!

mackowiakp · 12-22-2019, 09:53 PM

Quote:

One of the better resources is https://unix.stackexchange.com/quest...cannot-umount; the second answer provides steps to get rid of the problem.

Disabling NFS v2/3 server compatibility on QNAP NAS resolved the problem. It is strange for me because in this case I use NFS client from NAS to mount share from another NFS server. But NFS server is still running of course in background on NAS.
Nevertheless, it resolved "Stale file handle" problem.
QNAP OS is still bizarre for me.