SMB2.0 won't mount using CIFS, works on smbclient

Since the recent disabling of SMB1, I've tried to update my mounts to use SMB2.

The top level mounts (\server\share$) work OK.

The subdirectory mounts, however,(\server\files\service\subfolder) no longer mount with the vers=2.0 option. I instead get the error message:

//fs01/files/Users/Nick /mnt/Nick cifs defaults,uid=1001,gid=1001,credentials=/etc/smb_auth,vers=2.0 0 0
mount error(38): Function not implemented

I can view the share using smbclient directly, with

smbclient -m SMB2 \\\\fs01\files\Users -D Nick -A /etc/smb_auth

but I cannot get it to work with mount.cifs or mount.

EDIT

I have now got it to work with:

//fs01/Users$/Nick /mnt/Nick cifs defaults,uid=1001,gid=1001,credentials=/etc/smb_auth,vers=2.0 0 0

Which is odd, as the top line worked fine with SMB1.0.

1 Answer

I had to use Linux 4.11.0 on Xenial to get SMB2 and DFS to work with automount/cifs-utils (we're using MIT krb5 for auth). 4.10.0, 4.8.0 and 4.4.0 gave "Function not implemented" IIRC.