Author: kib
Date: Sun Oct 17 16:30:33 2010
New Revision: 213983
URL: http://svn.freebsd.org/changeset/base/213983
Log:
Document vunref(9), add some important notes for vrele(9) and vput(9).
Merge all three manpages to one, removing separate file for vput(9).
MFC after: 1 week
Deleted:
head/share/man/man9/vput.9
Modified:
head/share/man/man9/Makefile
head/share/man/man9/vrele.9
Modified: head/share/man/man9/Makefile
==============================================================================
--- head/share/man/man9/Makefile Sun Oct 17 15:55:46 2010
(r213982)
+++ head/share/man/man9/Makefile Sun Oct 17 16:30:33 2010
(r213983)
@@ -364,7 +364,6 @@ MAN= accept_filter.9 \
VOP_STRATEGY.9 \
VOP_VPTOCNP.9 \
VOP_VPTOFH.9 \
- vput.9 \
vref.9 \
vrefcnt.9 \
vrele.9 \
@@ -1366,6 +1365,8 @@ MLINKS+=VOP_RDWR.9 VOP_READ.9 \
VOP_RDWR.9 VOP_WRITE.9
MLINKS+=VOP_REMOVE.9 VOP_RMDIR.9
MLINKS+=vref.9 VREF.9
+MLINKS+=vrele.9 vput.9 \
+ vrele.9 vunref.9
MLINKS+=vslock.9 vsunlock.9
MLINKS+=zero_copy.9 zero_copy_sockets.9
MLINKS+=zone.9 uma.9 \
Modified: head/share/man/man9/vrele.9
==============================================================================
--- head/share/man/man9/vrele.9 Sun Oct 17 15:55:46 2010 (r213982)
+++ head/share/man/man9/vrele.9 Sun Oct 17 16:30:33 2010 (r213983)
@@ -1,6 +1,7 @@
.\" -*- nroff -*-
.\"
.\" Copyright (c) 1996 Doug Rabson
+.\" Copyright (c) 2010 Konstantin Belousov <k...@freebsd.org>
.\"
.\" All rights reserved.
.\"
@@ -28,17 +29,23 @@
.\"
.\" $FreeBSD$
.\"
-.Dd July 24, 1996
+.Dd October 17, 2010
.Dt VRELE 9
.Os
.Sh NAME
-.Nm vrele
+.Nm vput ,
+.Nm vrele ,
+.Nm vunref
.Nd decrement the use count for a vnode
.Sh SYNOPSIS
.In sys/param.h
.In sys/vnode.h
.Ft void
+.Fn vput "struct vnode *vp"
+.Ft void
.Fn vrele "struct vnode *vp"
+.Ft void
+.Fn vunref "struct vnode *vp"
.Sh DESCRIPTION
Decrement the
.Va v_usecount
@@ -48,18 +55,51 @@ field of a vnode.
the vnode to decrement
.El
.Pp
-Any code in the system which is using a vnode should call
+The
.Fn vrele
-when it is finished with the vnode.
+function takes an unlocked vnode and returns with the vnode unlocked.
+.Pp
+.The
+.Fn vput
+function should be given a locked vnode as argument, the vnode is unlocked
+after the function returned.
+The
+.Fn vput
+is operationally equivalent to calling
+.Xr VOP_UNLOCK 9
+followed by
+.Xr vrele 9 ,
+with less overhead.
+.Pp
+The
+.Fn vunref
+function takes a locked vnode as argument, and returns with the vnode locked.
+Nonetheless, the
+.Fn vunref
+might drop the vnode lock during the operation, so caller should not expect
+that non-doomed vnode is still non-doomed after the function returned.
+.Pp
+Any code in the system which signified its use of a vnode by usecount
+should call one of the listed function to decrement use counter.
If the
.Va v_usecount
-field of the vnode reaches zero, then it will be placed on the free list.
+field of the non-doomed vnode reaches zero, then it will be inactivated
+and placed on the free list.
+Since the functions might need to call VOPs for the vnode, the
+.Va Giant
+mutex should be conditionally locked around the call.
+.Pp
+The hold count for the vnode is always greater or equal to the usecount.
+Non-forced unmount fails when mount point owns a vnode that has non-zero
+usecount, see
+.Xr vflush 9 .
.Sh SEE ALSO
.Xr vget 9 ,
.Xr vnode 9 ,
-.Xr vput 9 ,
.Xr vref 9 ,
.Xr vrefcnt 9
.Sh AUTHORS
This manual page was written by
-.An Doug Rabson .
+.An Doug Rabson
+and
+.An Konstantin Belousov .
_______________________________________________
svn-src-all@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
