Comment 3 for bug 1687273

Not sure if this helps. This is what DebugData looks like after disconnecting.
% cat /proc/fs/cifs/DebugData
Display Internal CIFS Data Structures for Debugging
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CIFS Version 2.08
Features: dfs fscache lanman posix spnego xattr acl
Active VFS Requests: 0
Servers:
Number of credits: 1
1) Name: <redacted> Domain: WORKGROUP Uses: 1 OS: Windows 6.1
        NOS: Samba 4.3.13 Capability: 0x8080f3fc
        SMB session status: 1 TCP status: 4
        Local Users To Server: 1 SecMode: 0x7 Req On Wire: 1
        Shares:
        1) \\<redacted> Mounts: 1 Type: NTFS DevInfo: 0x20 Attributes: 0x1002f
        PathComponentMax: 255 Status: 1 type: DISK DISCONNECTED

        MIDs:
        State: 2 com: 43 pid: 4894 cbdata: ffff88007aee6000 mid 0