Module Name:	syssrc
Committed By:	wrstuden
Date:		Thu Jul  8 01:19:08 UTC 1999

Modified Files:
	syssrc/sys/miscfs/genfs: Makefile genfs.h genfs_vnops.c
	syssrc/sys/miscfs/nullfs: null.h null_vfsops.c null_vnops.c
	syssrc/sys/miscfs/umapfs: umap.h umap_subr.c umap_vfsops.c umap_vnops.c
Added Files:
	syssrc/sys/miscfs/genfs: layer.h layer_extern.h layer_subr.c
	    layer_vfsops.c layer_vnops.c
Removed Files:
	syssrc/sys/miscfs/nullfs: null_subr.c

Log Message:
Introduce layer library in genfs. This set of files abstracts most of
the functionality of nullfs. The latter is now just a mount & unmount
routine, and a few tables. umapfs borrow most of this infrastructure.

Both fs's are now nfs-exportable.

All layered fs's share a common format to private mount & private
vnode structs (which a particular fs can extend).

Also add genfs_noerr_rele(), a vnode op which will vrele/vput
operand vnodes appropriately.


To generate a diff of this commit:
cvs rdiff -r1.1 -r1.2 syssrc/sys/miscfs/genfs/Makefile
cvs rdiff -r1.8 -r1.9 syssrc/sys/miscfs/genfs/genfs.h
cvs rdiff -r1.11 -r1.12 syssrc/sys/miscfs/genfs/genfs_vnops.c
cvs rdiff -r0 -r1.1 syssrc/sys/miscfs/genfs/layer.h \
    syssrc/sys/miscfs/genfs/layer_extern.h \
    syssrc/sys/miscfs/genfs/layer_subr.c \
    syssrc/sys/miscfs/genfs/layer_vfsops.c \
    syssrc/sys/miscfs/genfs/layer_vnops.c
cvs rdiff -r1.9 -r1.10 syssrc/sys/miscfs/nullfs/null.h
cvs rdiff -r1.14 -r0 syssrc/sys/miscfs/nullfs/null_subr.c
cvs rdiff -r1.23 -r1.24 syssrc/sys/miscfs/nullfs/null_vfsops.c
cvs rdiff -r1.15 -r1.16 syssrc/sys/miscfs/nullfs/null_vnops.c
cvs rdiff -r1.8 -r1.9 syssrc/sys/miscfs/umapfs/umap.h
cvs rdiff -r1.14 -r1.15 syssrc/sys/miscfs/umapfs/umap_subr.c \
    syssrc/sys/miscfs/umapfs/umap_vnops.c
cvs rdiff -r1.22 -r1.23 syssrc/sys/miscfs/umapfs/umap_vfsops.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.