Module Name:	src
Committed By:	thorpej
Date:		Wed May  5 20:01:13 UTC 1999

Modified Files:
	src/sys/compat/common: vfs_syscalls_12.c vfs_syscalls_43.c
	src/sys/compat/hpux: hpux_net.c
	src/sys/compat/ibcs2: ibcs2_misc.c ibcs2_stat.c
	src/sys/compat/linux/common: linux_misc.c linux_socket.c
	src/sys/compat/netbsd32: netbsd32_netbsd.c
	src/sys/compat/osf1: osf1_descrip.c osf1_mount.c
	src/sys/compat/ossaudio: ossaudio.c
	src/sys/compat/sunos: sunos_misc.c
	src/sys/compat/svr4: svr4_misc.c svr4_net.c
	src/sys/compat/ultrix: ultrix_misc.c ultrix_pathname.c
	src/sys/kern: exec_script.c kern_descrip.c kern_ktrace.c sys_generic.c
	    uipc_syscalls.c uipc_usrreq.c vfs_syscalls.c
	src/sys/miscfs/portal: portal_vfsops.c
	src/sys/nfs: nfs_syscalls.c
	src/sys/sys: file.h
Log Message:
Add "use counting" to file entries.  When closing a file, and it's reference
count is 0, wait for use count to drain before finishing the close.

This is necessary in order for multiple processes to safely share file
descriptor tables.