I hit this error while adding a samba mount to my fstab, but mounting the same end point would work when executed from command line. For my scenario it turns out that it might be an issue with cifs-utils or kernel if your mount point is under more than one sub-directory. My solution was to go with option 3 and have my target as a share
"//host.IPAddress/share/subdir/subdir/target" - This failed with error "CIFS VFS: cifs_mount failed w/return code = -2"
"//host.IPAddress/share/target" - This worked
"//host.IPAddress/target" - This worked