In the words of the submitter:

---------
Make callers of namei() responsible for releasing references or locks
instead of having the underlying filesystems do it.  This eliminates
redundancy in all terminal filesystems and makes it possible for stacked
transport layers such as umapfs or nullfs to operate correctly.

Quality testing was done with testvn, and lat_fs from the lmbench suite.

Some NFS client testing courtesy of Patrik Kudo.

vop_mknod and vop_symlink still release the returned vpp.  vop_rename
still releases 4 vnode arguments before it returns.  These remaining cases
will be corrected in the next set of patches.
---------

Submitted by:	Michael Hancock <michaelh@cet.co.jp>

5 files changed, 75 insertions, 59 deletions

diff --git a/sys/kern/uipc_usrreq.c b/sys/kern/uipc_usrreq.c
index 8ca43f5..b225c7c 100644
--- a/sys/kern/uipc_usrreq.c
+++ b/sys/kern/uipc_usrreq.c
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	From: @(#)uipc_usrreq.c	8.3 (Berkeley) 1/4/94
- *	$Id: uipc_usrreq.c,v 1.32 1998/02/06 12:13:28 eivind Exp $
+ *	$Id: uipc_usrreq.c,v 1.33 1998/04/17 22:36:50 des Exp $
  */
 
 #include <sys/param.h>
@@ -549,7 +549,9 @@ unp_bind(unp, nam, p)
 	vattr.va_type = VSOCK;
 	vattr.va_mode = (ACCESSPERMS & ~p->p_fd->fd_cmask);
 	VOP_LEASE(nd.ni_dvp, p, p->p_ucred, LEASE_WRITE);
-	if (error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr))
+	error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr);
+	vput(nd.ni_dvp);
+	if (error)
 		return (error);
 	vp = nd.ni_vp;
 	vp->v_socket = unp->unp_socket;
diff --git a/sys/kern/vfs_extattr.c b/sys/kern/vfs_extattr.c
index e96b515..7fd30cc 100644
--- a/sys/kern/vfs_extattr.c
+++ b/sys/kern/vfs_extattr.c
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)vfs_syscalls.c	8.13 (Berkeley) 4/15/94
- * $Id: vfs_syscalls.c,v 1.97 1998/04/08 18:31:57 wosch Exp $
+ * $Id: vfs_syscalls.c,v 1.99 1998/04/19 22:20:32 des Exp $
  */
 
 /* For 4.3 integer FS ID compatibility */
@@ -1042,6 +1042,7 @@ mknod(p, uap)
 		} else {
 			error = VOP_MKNOD(nd.ni_dvp, &nd.ni_vp,
 						&nd.ni_cnd, &vattr);
+			vput(nd.ni_dvp);
 		}
 	} else {
 		VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
@@ -1095,7 +1096,9 @@ mkfifo(p, uap)
 	vattr.va_type = VFIFO;
 	vattr.va_mode = (SCARG(uap, mode) & ALLPERMS) &~ p->p_fd->fd_cmask;
 	VOP_LEASE(nd.ni_dvp, p, p->p_ucred, LEASE_WRITE);
-	return (VOP_MKNOD(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr));
+	error = VOP_MKNOD(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr);
+	vput(nd.ni_dvp);
+	return (error);
 }
 
 /*
@@ -1132,10 +1135,6 @@ link(p, uap)
 		if (!error) {
 			if (nd.ni_vp != NULL) {
 				VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
-				if (nd.ni_dvp == nd.ni_vp)
-					vrele(nd.ni_dvp);
-				else
-					vput(nd.ni_dvp);
 				if (nd.ni_vp)
 					vrele(nd.ni_vp);
 				error = EEXIST;
@@ -1145,6 +1144,10 @@ link(p, uap)
 				VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
 				error = VOP_LINK(nd.ni_dvp, vp, &nd.ni_cnd);
 			}
+			if (nd.ni_dvp == nd.ni_vp)
+				vrele(nd.ni_dvp);
+			else
+				vput(nd.ni_dvp);
 		}
 	}
 	vrele(vp);
@@ -1196,6 +1199,7 @@ symlink(p, uap)
 	vattr.va_mode = ACCESSPERMS &~ p->p_fd->fd_cmask;
 	VOP_LEASE(nd.ni_dvp, p, p->p_ucred, LEASE_WRITE);
 	error = VOP_SYMLINK(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr, path);
+	vput(nd.ni_dvp);
 	ASSERT_VOP_UNLOCKED(nd.ni_dvp, "symlink");
 	ASSERT_VOP_UNLOCKED(nd.ni_vp, "symlink");
 out:
@@ -1287,13 +1291,13 @@ unlink(p, uap)
 		error = VOP_REMOVE(nd.ni_dvp, vp, &nd.ni_cnd);
 	} else {
 		VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
-		if (nd.ni_dvp == vp)
-			vrele(nd.ni_dvp);
-		else
-			vput(nd.ni_dvp);
-		if (vp != NULLVP)
-			vput(vp);
 	}
+	if (nd.ni_dvp == vp)
+		vrele(nd.ni_dvp);
+	else
+		vput(nd.ni_dvp);
+	if (vp != NULLVP)
+		vput(vp);
 	ASSERT_VOP_UNLOCKED(nd.ni_dvp, "unlink");
 	ASSERT_VOP_UNLOCKED(nd.ni_vp, "unlink");
 	return (error);
@@ -2334,6 +2338,7 @@ mkdir(p, uap)
 	vattr.va_mode = (SCARG(uap, mode) & ACCESSPERMS) &~ p->p_fd->fd_cmask;
 	VOP_LEASE(nd.ni_dvp, p, p->p_ucred, LEASE_WRITE);
 	error = VOP_MKDIR(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr);
+	vput(nd.ni_dvp);
 	if (!error)
 		vput(nd.ni_vp);
 	ASSERT_VOP_UNLOCKED(nd.ni_dvp, "mkdir");
@@ -2389,12 +2394,13 @@ out:
 		error = VOP_RMDIR(nd.ni_dvp, nd.ni_vp, &nd.ni_cnd);
 	} else {
 		VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
-		if (nd.ni_dvp == vp)
-			vrele(nd.ni_dvp);
-		else
-			vput(nd.ni_dvp);
-		vput(vp);
 	}
+	if (nd.ni_dvp == vp)
+		vrele(nd.ni_dvp);
+	else
+		vput(nd.ni_dvp);
+	if (vp != NULLVP)
+		vput(vp);
 	ASSERT_VOP_UNLOCKED(nd.ni_dvp, "rmdir");
 	ASSERT_VOP_UNLOCKED(nd.ni_vp, "rmdir");
 	return (error);
diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c
index e96b515..7fd30cc 100644
--- a/sys/kern/vfs_syscalls.c
+++ b/sys/kern/vfs_syscalls.c
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)vfs_syscalls.c	8.13 (Berkeley) 4/15/94
- * $Id: vfs_syscalls.c,v 1.97 1998/04/08 18:31:57 wosch Exp $
+ * $Id: vfs_syscalls.c,v 1.99 1998/04/19 22:20:32 des Exp $
  */
 
 /* For 4.3 integer FS ID compatibility */
@@ -1042,6 +1042,7 @@ mknod(p, uap)
 		} else {
 			error = VOP_MKNOD(nd.ni_dvp, &nd.ni_vp,
 						&nd.ni_cnd, &vattr);
+			vput(nd.ni_dvp);
 		}
 	} else {
 		VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
@@ -1095,7 +1096,9 @@ mkfifo(p, uap)
 	vattr.va_type = VFIFO;
 	vattr.va_mode = (SCARG(uap, mode) & ALLPERMS) &~ p->p_fd->fd_cmask;
 	VOP_LEASE(nd.ni_dvp, p, p->p_ucred, LEASE_WRITE);
-	return (VOP_MKNOD(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr));
+	error = VOP_MKNOD(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr);
+	vput(nd.ni_dvp);
+	return (error);
 }
 
 /*
@@ -1132,10 +1135,6 @@ link(p, uap)
 		if (!error) {
 			if (nd.ni_vp != NULL) {
 				VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
-				if (nd.ni_dvp == nd.ni_vp)
-					vrele(nd.ni_dvp);
-				else
-					vput(nd.ni_dvp);
 				if (nd.ni_vp)
 					vrele(nd.ni_vp);
 				error = EEXIST;
@@ -1145,6 +1144,10 @@ link(p, uap)
 				VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
 				error = VOP_LINK(nd.ni_dvp, vp, &nd.ni_cnd);
 			}
+			if (nd.ni_dvp == nd.ni_vp)
+				vrele(nd.ni_dvp);
+			else
+				vput(nd.ni_dvp);
 		}
 	}
 	vrele(vp);
@@ -1196,6 +1199,7 @@ symlink(p, uap)
 	vattr.va_mode = ACCESSPERMS &~ p->p_fd->fd_cmask;
 	VOP_LEASE(nd.ni_dvp, p, p->p_ucred, LEASE_WRITE);
 	error = VOP_SYMLINK(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr, path);
+	vput(nd.ni_dvp);
 	ASSERT_VOP_UNLOCKED(nd.ni_dvp, "symlink");
 	ASSERT_VOP_UNLOCKED(nd.ni_vp, "symlink");
 out:
@@ -1287,13 +1291,13 @@ unlink(p, uap)
 		error = VOP_REMOVE(nd.ni_dvp, vp, &nd.ni_cnd);
 	} else {
 		VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
-		if (nd.ni_dvp == vp)
-			vrele(nd.ni_dvp);
-		else
-			vput(nd.ni_dvp);
-		if (vp != NULLVP)
-			vput(vp);
 	}
+	if (nd.ni_dvp == vp)
+		vrele(nd.ni_dvp);
+	else
+		vput(nd.ni_dvp);
+	if (vp != NULLVP)
+		vput(vp);
 	ASSERT_VOP_UNLOCKED(nd.ni_dvp, "unlink");
 	ASSERT_VOP_UNLOCKED(nd.ni_vp, "unlink");
 	return (error);
@@ -2334,6 +2338,7 @@ mkdir(p, uap)
 	vattr.va_mode = (SCARG(uap, mode) & ACCESSPERMS) &~ p->p_fd->fd_cmask;
 	VOP_LEASE(nd.ni_dvp, p, p->p_ucred, LEASE_WRITE);
 	error = VOP_MKDIR(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr);
+	vput(nd.ni_dvp);
 	if (!error)
 		vput(nd.ni_vp);
 	ASSERT_VOP_UNLOCKED(nd.ni_dvp, "mkdir");
@@ -2389,12 +2394,13 @@ out:
 		error = VOP_RMDIR(nd.ni_dvp, nd.ni_vp, &nd.ni_cnd);
 	} else {
 		VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
-		if (nd.ni_dvp == vp)
-			vrele(nd.ni_dvp);
-		else
-			vput(nd.ni_dvp);
-		vput(vp);
 	}
+	if (nd.ni_dvp == vp)
+		vrele(nd.ni_dvp);
+	else
+		vput(nd.ni_dvp);
+	if (vp != NULLVP)
+		vput(vp);
 	ASSERT_VOP_UNLOCKED(nd.ni_dvp, "rmdir");
 	ASSERT_VOP_UNLOCKED(nd.ni_vp, "rmdir");
 	return (error);
diff --git a/sys/kern/vfs_vnops.c b/sys/kern/vfs_vnops.c
index 31d4f2c..efee10e 100644
--- a/sys/kern/vfs_vnops.c
+++ b/sys/kern/vfs_vnops.c
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)vfs_vnops.c	8.2 (Berkeley) 1/21/94
- * $Id: vfs_vnops.c,v 1.55 1998/04/08 18:31:58 wosch Exp $
+ * $Id: vfs_vnops.c,v 1.56 1998/04/10 00:09:04 alex Exp $
  */
 
 #include <sys/param.h>
@@ -95,8 +95,10 @@ vn_open(ndp, fmode, cmode)
 			if (fmode & O_EXCL)
 				vap->va_vaflags |= VA_EXCLUSIVE;
 			VOP_LEASE(ndp->ni_dvp, p, cred, LEASE_WRITE);
-			if (error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp,
-			    &ndp->ni_cnd, vap))
+			error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp,
+					   &ndp->ni_cnd, vap);
+			vput(ndp->ni_dvp);
+			if (error)
 				return (error);
 			ASSERT_VOP_UNLOCKED(ndp->ni_dvp, "create");
 			ASSERT_VOP_LOCKED(ndp->ni_vp, "create");
diff --git a/sys/kern/vnode_if.src b/sys/kern/vnode_if.src
index 922e060..c97d2ad 100644
--- a/sys/kern/vnode_if.src
+++ b/sys/kern/vnode_if.src
@@ -31,7 +31,7 @@
 # SUCH DAMAGE.
 #
 #	@(#)vnode_if.src	8.12 (Berkeley) 5/14/95
-# $Id: vnode_if.src,v 1.15 1997/10/16 20:32:23 phk Exp $
+# $Id: vnode_if.src,v 1.16 1998/03/08 09:57:26 julian Exp $
 #
 
 #
@@ -77,11 +77,11 @@ vop_cachedlookup {
 };
 
 #
-#% create	dvp	L U U
+#% create	dvp	L L L
 #% create	vpp	- L -
 #
 vop_create {
-	IN WILLRELE struct vnode *dvp;
+	IN struct vnode *dvp;
 	OUT struct vnode **vpp;
 	IN struct componentname *cnp;
 	IN struct vattr *vap;
@@ -93,17 +93,17 @@ vop_create {
 #% whiteout	flag	- - -
 #
 vop_whiteout {
-	IN WILLRELE struct vnode *dvp;
+	IN struct vnode *dvp;
 	IN struct componentname *cnp;
 	IN int flags;
 };
 
 #
-#% mknod	dvp	L U U
+#% mknod	dvp	L L L
 #% mknod	vpp	- X -
 #
 vop_mknod {
-	IN WILLRELE struct vnode *dvp;
+	IN struct vnode *dvp;
 	OUT WILLRELE struct vnode **vpp;
 	IN struct componentname *cnp;
 	IN struct vattr *vap;
@@ -240,21 +240,21 @@ vop_fsync {
 };
 
 #
-#% remove	dvp	L U U
-#% remove	vp	L U U
+#% remove	dvp	L L L
+#% remove	vp	L L L
 #
 vop_remove {
-	IN WILLRELE struct vnode *dvp;
-	IN WILLRELE struct vnode *vp;
+	IN struct vnode *dvp;
+	IN struct vnode *vp;
 	IN struct componentname *cnp;
 };
 
 #
+#% link		tdvp	L L L
 #% link		vp	U U U
-#% link		tdvp	L U U
 #
 vop_link {
-	IN WILLRELE struct vnode *tdvp;
+	IN struct vnode *tdvp;
 	IN struct vnode *vp;
 	IN struct componentname *cnp;
 };
@@ -275,28 +275,28 @@ vop_rename {
 };
 
 #
-#% mkdir	dvp	L U U
+#% mkdir	dvp	L L L
 #% mkdir	vpp	- L -
 #
 vop_mkdir {
-	IN WILLRELE struct vnode *dvp;
+	IN struct vnode *dvp;
 	OUT struct vnode **vpp;
 	IN struct componentname *cnp;
 	IN struct vattr *vap;
 };
 
 #
-#% rmdir	dvp	L U U
-#% rmdir	vp	L U U
+#% rmdir	dvp	L L L
+#% rmdir	vp	L L L
 #
 vop_rmdir {
-	IN WILLRELE struct vnode *dvp;
-	IN WILLRELE struct vnode *vp;
+	IN struct vnode *dvp;
+	IN struct vnode *vp;
 	IN struct componentname *cnp;
 };
 
 #
-#% symlink	dvp	L U U
+#% symlink	dvp	L L L
 #% symlink	vpp	- U -
 #
 # XXX - note that the return vnode has already been VRELE'ed
@@ -304,7 +304,7 @@ vop_rmdir {
 #	possibly with a further namei.
 #
 vop_symlink {
-	IN WILLRELE struct vnode *dvp;
+	IN struct vnode *dvp;
 	OUT WILLRELE struct vnode **vpp;
 	IN struct componentname *cnp;
 	IN struct vattr *vap;