decouple file system server start/termination from mount/umount

man/man2/mount.2

@@ -8,6 +8,7 @@ mount, umount \- mount or umount a file system
 
 int mount(char *\fIspecial\fP, char *\fIname\fP, int \fImountflags\fP, char *\fItype\fP, char *\fIargs\fP)
 int umount(char *\fIname\fP)
+int umount2(char *\fIname\fP, int \fIflags)
 .fi
 .ft P
 .SH DESCRIPTION
@@ -38,6 +39,11 @@ Mount file system read-only, rather than read-write.
 .TP
 .B MS_REUSE
 Reuse the file system server image if possible.
+.TP
+.B MS_EXISTING
+Do not start the file system server, but use existing one. The label of 
+the running file server is specified in 
+.I Type.
 .PP
 .I Type
 is the type of the file system (e.g. "mfs"), used to pick a file system server.
@@ -55,7 +61,18 @@ same mount point then unmounting at the mount point removes the last mounted
 device, unmounting a device removes precisely that device.  The unmount will
 only succeed if none of the files on the device are in use.
 .PP
-Both calls may only be executed by the super-user.
+.B Umount2()
+Same as Umount(), but takes an additional 
+.I flags
+parameter. 
+.I Flags 
+may be a bitwise combination of the following flags:
+.TP 2
+.B MS_EXISTING
+Umount the file system but do not terminate the the file system server.
+.PP
+.TO
+These calls may only be executed by the super-user.
 .SH "SEE ALSO"
 .BR mount (1),
 .BR umount (1).