For some reason, when the monted device is "/dev/mapper/*", a record
in the form "/dev/dm-*" ends up in /etc/mtab and the device cannot be
unmounted.
The reason is unclear, the /dev/mapper name is not a symlink, and the
function doing the name change is not known. No detailed feedback from
the users having met the issue.
The patch changes the name back to the /dev/mapper name after realpath()
is called, and, if there is an actual change, both the name passed to
ntfs-3g and the one passed to fuse and mount are logged in the hope
of getting a clue about what is happening.
But ntfs-3g is probably not the right place for a fix.
571dbc5784