[PATCH 4/5] mountmgr.sys: Add the ability to query filesystem attributes on a file handle.

[Erich E. Hoover]

This patch adds capability to the new IOCTL_MOUNTMGR_QUERY_VOLUME
ioctl to be able to return volume information on a file handle.  This
code represents the "fallback" case when standard volume information
is unavailable (for more details see the code removed from
dlls/ntdll/unix/file.c in patch 5 in the case where
get_mountmgr_fs_info() fails).

Best,
Erich