vnode.9: Document vnode_if.awk and vnode_if.src

Discussed with:	bjk, imp
Reviewed by:	kib
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D27196

share/man/man9/vnode.9

@@ -24,7 +24,7 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd February 12, 2014
+.Dd October 9, 2024
 .Dt VNODE 9
 .Os
 .Sh NAME
@@ -104,9 +104,21 @@ the vnode.
 The
 .Va v_op
 field is used by the
-.Dv VOP_*
-macros to call functions in the file system which implement the vnode's
+.Fn VOP_*
+functions to call functions in the file system which implement the vnode's
 functionality.
+.Pp
+The
+.Fn VOP_*
+function declarations and definitions are generated from
+.Pa sys/kern/vnode_if.src
+by the
+.Pa sys/tools/vndoe_if.awk
+script.
+The interfaces are documented in their respective manual pages like
+.Xr VOP_READ 9
+and
+.Xr VOP_WRITE 9 .
 .Sh VNODE TYPES
 .Bl -tag -width VSOCK
 .It Dv VNON
@@ -154,6 +166,16 @@ when holding a
 .Nm
 interlock, will cause a LOR (Lock Order Reversal) due to the
 intertwining of VM Objects and Vnodes.
+.Sh FILES
+.Bl -tag -width "sys/tools/vnode_if.awk" -compact
+.It Pa sys/kern/vnode_if.src
+The input file for
+.Pa sys/tools/vnode_if.awk .
+.It Pa sys/tools/vnode_if.awk
+The script generating the source code of the
+.Fn VOP_*
+functions.
+.El
 .Sh SEE ALSO
 .Xr malloc 9 ,
 .Xr VFS 9 ,