Mounting SMB Shares in Fstab issues

Question

I just upgraded my file server from 16.04 to 20.04 and everything seems to be working except for my SMB mounts on my Ubuntu computer. I can access the SMB shares on my Windows computer but on my Ubuntu 18.04 computer I can't get the shares mounted in fstab.

If I mount the shares from the command line (command below) it is mounted just fine.

sudo mount -t cifs -o username=username,vers=3.0 //192.168.1.116/Share /mnt/Share/

However when I try to mount the share in fstab (command below) the smb share is not mounted.

//192.168.1.116/Share  /mnt/Share  cifs  credentials=/home/user/.smbcredentials,vers=3.0,iocharset=utf8,sec=ntlmssp  0  0

After doing a sudo mount -a and trying a ls I get:

ls: cannot access 'Share': Operation not supported

and when I do a smbclient -L //192.168.1.116 I get:

protocol negotiation failed: NT_STATUS_INVALID_NETWORK_RESPONSE

Update:

When I do a

sudo mount -t cifs -o credentials=/home/user/.smbcredentials,vers=3.0,iocharset=utf8,sec=ntlmssp //192.168.1.116/Share /mnt/Share/

The SMB share is mounted properly.

When I do a

smbclient -L //192.168.1.116 -d 0

I get the same result:

protocol negotiation failed: NT_STATUS_INVALID_NETWORK_RESPONSE.

dmesg -t | grep -e CIFS returns:

CIFS VFS: cifs_mount failed w/return code = -95

When I check dmesg with the debug turned on I get a lot of:

/build/linux-Dh1oQA/linux-4.4.0/fs/cifs/cifsfs.c: CIFS VFS: in cifs_statfs as Xid: 9405245 with uid: 1000

/build/linux-Dh1oQA/linux-4.4.0/fs/cifs/cifsfs.c: CIFS VFS: leaving cifs_statfs (xid = 9405245) rc = -95

/build/linux-Dh1oQA/linux-4.4.0/fs/cifs/inode.c: CIFS VFS: in cifs_revalidate_dentry_attr as Xid: 9405247 with uid: 1000

/build/linux-Dh1oQA/linux-4.4.0/fs/cifs/inode.c: CIFS VFS: leaving cifs_revalidate_dentry_attr (xid = 9405247) rc = -95

Answer 1

Would you try debug for smblient with?

smbclient -L //192.168.1.116 -d 0

Are you able to mount via the command line using the options and credentials file from fstab?

sudo mount -t cifs -o credentials=/home/user/.smbcredentials,vers=3.0,iocharset=utf8,sec=ntlmssp //192.168.1.116/Share /mnt/Share/

What are you getting in dmesg for CIFS errors?

dmesg -t | grep -e CIFS

We can also enable debug of the cifs module.

modprobe cifs
echo 'module cifs +p' > /sys/kernel/debug/dynamic_debug/control
echo 'file fs/cifs/* +p' > /sys/kernel/debug/dynamic_debug/control
echo 7 > /proc/fs/cifs/cifsFYI

and disable it with.

echo 0 > /proc/fs/cifs/cifsFYI

Check dmesg for the cifs module debug output also.

Answer 2

Not sure what happened but I was able to get this issue resolved.

I decided I'd start over and did a sudo umount /mnt/Share(s). After unmounting each directory I was about to use sudo mount -a and have my mount points in fstab all mount properly.

The clue was in an answer that is no longer available. The answer author (iirc @heynnema) asked me to put file_mode=0777,dir_mode=0777 in my fstab for a mount.

Fresh eyes this morning noticed that the directory was highlighted. A quick ls -l showed me it was 777 which wasn't right. I wasn't able to change it by adjusting fstab so I figured I'd start fresh again. Seems it worked this time around.

In the end I added to my;

smb.conf file

min client protocol = NT1
max client protocol = SMB3

/etc/fstab

vers=3.0

Even with min client protocol = NT1. The vers=3.0 was required.