Error mounting a CIFS storage

I was trying to mount several folders from my LAN NAS (Zyxel NAS542) to build an automated backup server and I kept bumping into this error:

$ sudo mount /mnt/nas/bagr
mount error(5): Input/output error
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)

$ dmesg | tail
[426845.904201] CIFS: Attempting to mount //
[426845.914365] CIFS: VFS: \\\bagr validate protocol negotiate failed: -13
[426845.915581] CIFS: VFS: cifs_mount failed w/return code = -5

The other folders from the same server mounted just fine. Just this one kept failing.

Then when I ssh-ed into the NAS I found out that the directory had incorrectly set permissions:

# ls -all
drwxrwxr-x   15 works    works         4096 Jan  9 16:12 works
drwxrwx---   15 bagr     bagr          4096 Jan  9 16:12 bagr

For some reason the directory needs to have the “others” permissions set to read and execute so that the CIFS (SMB/Samba) may access that.

To fix this, I just did:

# chmod o+rx bagr

Done! Now the storage mounts successfully!


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