Mount.cifs giving "operation not supported" after OS5 upgrade

[rlduffy]

Mounts of shares by Raspberry Pi quit working after OS5 upgrade. Meanwhile Win10 access is just fine. Needless to say the Pi was unchanged across the OS5 upgrade.

The fstab line is:

//nas/Public /nas cifs cred=/home/pi/.nas,rw 0 0

Mount fails:

pi1:~$ mount /nas
mount error(95): Operation not supported
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)
pi1:~$

Running v5.7 mount.cifs on the Pi.

I have tried every variation of the mount command I can think of. My Pi application is 100% down because of this. Any help appreciated.

[SBrown]

@rlduffy CIFS and NFS mount options are supported in My Cloud OS 5 5.08.115 firmware.
Please update your OS 5 device firmware to 5.08.115

[rlduffy]

@SBrown

w

Thanks for the reply. I am indeed running 5.08.115. I have no problem mounting the shares from Windows 10 and other Linux systems, but the mounts from the Raspberry Pi (which hasn’t changed from before the OS5 upgrade) consistently fail with the “Operation not supported” error.

[dhearns]

@rlduffy, I think SMB version 1 which you’re trying to use, is disabled by default in the My Cloud firmware now. I believe the default is version 2 & 3. Verify which SMB versions are enabled in the network settings of your NAS. If it’s infact set to ver 2 &3 try this:

//nas/Public /nas cifs vers=2.0,cred=/home/pi/.nas,rw 0 0

or

//nas/Public /nas cifs vers=3.0,cred=/home/pi/.nas,rw 0 0

I wouldn’t recommend it but you could also change your NAS settings to allow SMB 1, 2 & 3, etc.

[rlduffy]

Thank you, thank you, thank you. That did the trick. It never occurred to me that a protocol version conflict might yield the “operation not permitted” error. Thus far I haven’t found any documentation for “vers=” mount option, but I shall continue to research that.

Again THANKS.

[dhearns]

Glad it worked @rlduffy. From https://manpages.debian.org/testing/cifs-utils/mount.cifs.8.en.html

vers=arg

SMB protocol version. Allowed values are:

• 1.0 - The classic CIFS/SMBv1 protocol.
• 2.0 - The SMBv2.002 protocol. This was initially introduced in Windows Vista Service Pack 1, and Windows Server 2008. Note that the initial release version of Windows Vista spoke a slightly different dialect (2.000) that is not supported.
• 2.1 - The SMBv2.1 protocol that was introduced in Microsoft Windows 7 and Windows Server 2008R2.
• 3.0 - The SMBv3.0 protocol that was introduced in Microsoft Windows 8 and Windows Server 2012.
• 3.02 or 3.0.2 - The SMBv3.0.2 protocol that was introduced in Microsoft Windows 8.1 and Windows Server 2012R2.
• 3.1.1 or 3.11 - The SMBv3.1.1 protocol that was introduced in Microsoft Windows 10 and Windows Server 2016.
• 3 - The SMBv3.0 protocol version and above.
• default - Tries to negotiate the highest SMB2+ version supported by both the client and server.

If no dialect is specified on mount vers=default is used. To check Dialect refer to /proc/fs/cifs/DebugData

Note too that while this option governs the protocol version used, not all features of each version are available.

The default since v4.13.5 is for the client and server to negotiate the highest possible version greater than or equal to 2.1 . In kernels prior to v4.13, the default was 1.0 . For kernels between v4.13 and v4.13.5 the default is 3.0 .

[rlduffy]

And thank you once again for the documentation reference. Not an easy thing to find.