Bug 117687

Fields in /etc/fstab are separated with spaces and/or TAB characters.
No quoting/escaping mechanism is defined, therefore fields cannot
contain embedded SP or TAB characters.  This is very rarely a problem
but can become a nuisance in dual boot configurations where access to
NTFS and/or VFAT partitions is needed.

The first fstab(5) field (special device name) can contain embedded
spaces when GEOM_LABEL is used.  It is not unusual to name logical
partitions like e.g. "BART'S PICTURES" or "MY MOVIES".  Using
glabel(8) these would result in special devices named like
/dev/msdosfs/BART\'S\ PICTURES and /dev/ntfs/MY\ MOVIES.

Since path names can contain spaces there is obviously a possibility
that a mount point directory's path contains white space.

When all setup/configuration is done manually, one can work around the
cases above by restricting oneself to disk labels and mount paths
without white space.  However why impose that restriction when it can
be lifted trivially with five added lines of code?  And what about the
cases where /etc/fstab is auto-generated by say an installer program
or the auto-configuration script of a live CD/DVD?

Compatibility note: Escaping space as \040 is compatible with Linux's
fstab(5).  Backward compatibility should be no problem, except for the
extremely unlikely case of an existing /etc/fstab which contains a
*literal* pattern of \^C, \M-C, \M^C or \577 (cf. vis(3)).

Fix: Patch below is against RELENG_6 but differences to -current are
minimal.  Manpage patch also removes references to block devices.
They are gone for about 8 years now.