Suddenly can't mount Samba/CIFS read-write

[Ken g6]

Something has gone wrong with the following setup.

I have a Samba server on my main Ubuntu 16.04 machine, set with this in /etc/smb.conf:

[multimedia]
path = /multimedia
valid users = ken
read only = no

I mount it from a similar Ubuntu VM with this in /etc/fstab:

//192.168.1.12/multimedia /multimedia cifs username=ken,password=********,rw,auto,user,nodev,noexec,nobrl,uid=1000,gid=1000 0 0

It had been working for months. Now suddenly it only mounts read-only. Why?

 

[dave_the_nerd]

Is it read only on the server as well, or just to the clients? Sometimes I'll see Linux drop a filesystem in r/o mode if there's an I/O interruption.

 

[Ken g6]

I checked; I can write to it on the server.

 

[Ken g6]

In case anyone's wondering, the problem is currently solved by forwarding ports for SFTP from the server to the client, so I can connect the VPN to my workplace from the client but upload/download files from the server.