Comment 0 for bug 1638448

1) Ubu version is 14.04.1 but testing confirms this problem exists in other versions.
2) On 14.04.1 the cifs-utils version is 6.4 (though I include more on that via a link).
3) Files and folders with ? or : should be accessible (and have been up until at least 12.04).
4) File/folder not found errors and other behaviors outlined at the below link.

Ok. I've been working at sussing out this problem for a while now, and I think I'm finally getting close to the source of the matter.

In short, I have an Ubuntu server which is serving a number of shares using Samba. When I access any of those shares with, say, a 12.04 machine I have no problem with certain characters in file or folder names. However, newer versions of Ubuntu are not playing so nicely.

When those locations are mounted by mount (whether via fstab or no) using a 12.04 client machine the files and the folders which contain either (or both) of those characters in their respective paths are accessible as would be expected for any such file share.

There are at least two characters at odds with these newer versions of Ubuntu: the colon (:) and the question mark (?). I have mangled file names disabled, and remember Ubuntu 12.04 is accessing these files and folders without any trouble. Newer versions may error (can't find object) on either or both a file or folder name.

I have created a complete testing matrix here.

http://jamesisin.com/a_high-tech_blech/index.php/2016/10/notes-from-possible-cifs-utils-bug/

There you will find Ubuntu versions, cifs-utils versions, and comparisons of the behaviors for each character and comparisons with mounts created using Nautilus.

I am happy to help in any way I am able.