Created attachment 7998 [details]
Step creating a multicase directories with the same case-insensitive name

NTFS (and thus Explorer) supports case sensitive filesystem pathing semantics [1], so the statement in smb.conf that claims the following...

       case sensitive = yes/no/auto

           ...

           case sensitive semantics). No Windows or DOS system supports
                                      ^^^^^^^^^^        ^^^^^^^^^^^^^^^
           case-sensitive filename so setting this option to auto is that same
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
           as setting it to no for them. Default auto.
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

... is bogus on some versions of Windows (I know for certain it's bogus on Windows 7/Windows 2008 R2). The problem is that once upon a time (and on some supported Windows versions still, e.g. XP) the Win32 filesystem APIs were/are busted; I suspect that that's no longer an issue with non-Win32 apps on Windows x64 edition, but CIFS 1.x also does support case sensitivity depending upon the underlying filesystem (see FILE_CASE_SENSITIVE_SEARCH in [2]; FILE_CASE_SENSITIVE_SEARCH and FILE_CASE_PRESERVED_NAMES in [3]).

Some CIFS implementations claim to explicitly only support case-preservation (see NetApp's documentation), whereas Solaris supports mixed-case support, depending on the filesystem mode [2]. Isilon's release versions of OneFS don't appear to support mixed mode/case sensitivity [out-of-the-box] with the Likewise SMB `engine`, but they permit directory merging (`a` exists and `A` is being created/moved -- do you want to merge the views of the 2 directories?). Samba 3.6.7 does something unintuitive to Windows users and only presents the contents of whichever case wins in the path sorting algorithm employed if two or more paths exist with the same case insensitive contents, e.g. if I have `a` and `A`, samba 3.7.3 will only show me the contents of `A` and not `a`. Unfortunately this isn't helpful and is confusing when admins are dealing with mixed case client environments (Unix + Windows).

My smb.conf is as follows:

$ testparm 2>/dev/null < /dev/null
[global]
        server string = BAYONETTA
        max log size = 50
        socket options = SO_RCVBUF=64240 SO_SNDBUF=64240 TCP_NODELAY IPTOS_LOWDELAY IPTOS_THROUGHPUT
        load printers = No
        preferred master = Yes
        idmap config * : backend = tdb
        inherit acls = Yes
        aio read size = 65536
        aio write size = 65536
        map acl inherit = Yes
        directory name cache size = 0
        write cache size = 65536
        case sensitive = Yes

[scratch]
        path = /scratch
        read only = No
        veto files = /.snap/.windows/.zfs/
        vfs objects = zfsacl, shadow_copy2

[store]
        path = /store
        read only = No
        veto files = /.snap/.windows/.zfs/
        vfs objects = zfsacl, shadow_copy2
$ testparm --version
Version 3.6.7

I've attached screenshots will better illustrate what's going on with Samba.

Procedure:

1. Set `case sensitive = Yes` in the global configuration for smb.conf to force Samba to differentiate mixed-case paths.
2. Reload your samba configuration in smbd/nmbd.
3. On a unix host, cd to the share under inspection, and run `mkdir Foo foo; touch Foo/bar1 foo/bar2`.
4. Go back to Windows and note that there will be 2 separate paths available in Explorer: Foo and foo.
5. Go into each of the directories and you'll note that one set of contents is available, either bar1 or bar2 -- in my case it was equivalent to "bar1", I assume because strcmp("Foo", "foo") < 0.

References:

1. http://support.microsoft.com/kb/100625
2. http://msdn.microsoft.com/en-us/library/cc246322%28prot.20%29.aspx
3. http://msdn.microsoft.com/en-us/library/cc246323%28prot.20%29.aspx
3. http://docs.oracle.com/cd/E19082-01/820-2429/smbenvironmentoverview/index.html