Add three new VOPs: VOP_CREATEVOBJECT, VOP_DESTROYVOBJECT and VOP_GETVOBJECT.

They will be used by nullfs and other stacked filesystems to support full
cache coherency.

Reviewed in general by:	mckusick, dillon

13 files changed, 201 insertions, 166 deletions

diff --git a/sys/kern/imgact_aout.c b/sys/kern/imgact_aout.c
index 6d93a72..80ecc0c 100644
--- a/sys/kern/imgact_aout.c
+++ b/sys/kern/imgact_aout.c
@@ -179,7 +179,7 @@ exec_aout_imgact(imgp)
 	vp = imgp->vp;
 	map = &vmspace->vm_map;
 	vm_map_lock(map);
-	object = vp->v_object;
+	VOP_GETVOBJECT(vp, &object);
 	vm_object_reference(object);
 
 	text_end = virtual_offset + a_out->a_text;
diff --git a/sys/kern/imgact_elf.c b/sys/kern/imgact_elf.c
index f692c80..dac862a 100644
--- a/sys/kern/imgact_elf.c
+++ b/sys/kern/imgact_elf.c
@@ -187,7 +187,7 @@ elf_load_section(struct proc *p, struct vmspace *vmspace, struct vnode *vp, vm_o
 	vm_offset_t file_addr;
 	vm_offset_t data_buf = 0;
 
-	object = vp->v_object;
+	VOP_GETVOBJECT(vp, &object);
 	error = 0;
 
 	/*
diff --git a/sys/kern/kern_exec.c b/sys/kern/kern_exec.c
index 5f6d2be..453447d 100644
--- a/sys/kern/kern_exec.c
+++ b/sys/kern/kern_exec.c
@@ -401,7 +401,7 @@ exec_map_first_page(imgp)
 		exec_unmap_first_page(imgp);
 	}
 
-	object = imgp->vp->v_object;
+	VOP_GETVOBJECT(imgp->vp, &object);
 	s = splvm();
 
 	ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
diff --git a/sys/kern/uipc_syscalls.c b/sys/kern/uipc_syscalls.c
index ed9d691..e231a83 100644
--- a/sys/kern/uipc_syscalls.c
+++ b/sys/kern/uipc_syscalls.c
@@ -1434,8 +1434,7 @@ sendfile(struct proc *p, struct sendfile_args *uap)
 	}
 	vp = (struct vnode *)fp->f_data;
 	vref(vp);
-	obj = vp->v_object;
-	if (vp->v_type != VREG || obj == NULL) {
+	if (vp->v_type != VREG || VOP_GETVOBJECT(vp, &obj) != 0) {
 		error = EINVAL;
 		goto done;
 	}
diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c
index 34cff17..11e9183 100644
--- a/sys/kern/vfs_bio.c
+++ b/sys/kern/vfs_bio.c
@@ -1027,7 +1027,7 @@ brelse(struct buf * bp)
 			vm_page_flag_clear(m, PG_ZERO);
 			if (m == bogus_page) {
 
-				obj = (vm_object_t) vp->v_object;
+				VOP_GETVOBJECT(vp, &obj);
 				poff = OFF_TO_IDX(bp->b_offset);
 
 				for (j = i; j < bp->b_npages; j++) {
@@ -1905,10 +1905,9 @@ inmem(struct vnode * vp, daddr_t blkno)
 		return 1;
 	if (vp->v_mount == NULL)
 		return 0;
-	if ((vp->v_object == NULL) || (vp->v_flag & VOBJBUF) == 0)
+	if (VOP_GETVOBJECT(vp, &obj) != 0 || (vp->v_flag & VOBJBUF) == 0)
 		return 0;
 
-	obj = vp->v_object;
 	size = PAGE_SIZE;
 	if (size > vp->v_mount->mnt_stat.f_iosize)
 		size = vp->v_mount->mnt_stat.f_iosize;
@@ -2193,7 +2192,7 @@ loop:
 			bsize = size;
 
 		offset = (off_t)blkno * bsize;
-		vmio = (vp->v_object != 0) && (vp->v_flag & VOBJBUF);
+		vmio = (VOP_GETVOBJECT(vp, NULL) == 0) && (vp->v_flag & VOBJBUF);
 		maxsize = vmio ? size + (offset & PAGE_MASK) : size;
 		maxsize = imax(maxsize, bsize);
 
@@ -2462,7 +2461,7 @@ allocbuf(struct buf *bp, int size)
 			 */
 
 			vp = bp->b_vp;
-			obj = vp->v_object;
+			VOP_GETVOBJECT(vp, &obj);
 
 			while (bp->b_npages < desiredpages) {
 				vm_page_t m;
@@ -2641,7 +2640,7 @@ bufdonebio(struct bio *bp)
 void
 bufdone(struct buf *bp)
 {
-	int s;
+	int s, error;
 	void    (*biodone) __P((struct buf *));
 
 	s = splbio();
@@ -2680,14 +2679,14 @@ bufdone(struct buf *bp)
 		int iosize;
 		struct vnode *vp = bp->b_vp;
 
-		obj = vp->v_object;
+		error = VOP_GETVOBJECT(vp, &obj);
 
 #if defined(VFS_BIO_DEBUG)
 		if (vp->v_usecount == 0) {
 			panic("biodone: zero vnode ref count");
 		}
 
-		if (vp->v_object == NULL) {
+		if (error) {
 			panic("biodone: missing VM object");
 		}
 
@@ -2700,7 +2699,7 @@ bufdone(struct buf *bp)
 		KASSERT(bp->b_offset != NOOFFSET,
 		    ("biodone: no buffer offset"));
 
-		if (!obj) {
+		if (error) {
 			panic("biodone: no object");
 		}
 #if defined(VFS_BIO_DEBUG)
@@ -2821,7 +2820,9 @@ vfs_unbusy_pages(struct buf * bp)
 
 	if (bp->b_flags & B_VMIO) {
 		struct vnode *vp = bp->b_vp;
-		vm_object_t obj = vp->v_object;
+		vm_object_t obj;
+
+		VOP_GETVOBJECT(vp, &obj);
 
 		for (i = 0; i < bp->b_npages; i++) {
 			vm_page_t m = bp->b_pages[i];
@@ -2898,9 +2899,10 @@ vfs_busy_pages(struct buf * bp, int clear_modify)
 
 	if (bp->b_flags & B_VMIO) {
 		struct vnode *vp = bp->b_vp;
-		vm_object_t obj = vp->v_object;
+		vm_object_t obj;
 		vm_ooffset_t foff;
 
+		VOP_GETVOBJECT(vp, &obj);
 		foff = bp->b_offset;
 		KASSERT(bp->b_offset != NOOFFSET,
 		    ("vfs_busy_pages: no buffer offset"));
diff --git a/sys/kern/vfs_default.c b/sys/kern/vfs_default.c
index e95e7e2..2b651c8 100644
--- a/sys/kern/vfs_default.c
+++ b/sys/kern/vfs_default.c
@@ -43,6 +43,7 @@
 #include <sys/systm.h>
 #include <sys/bio.h>
 #include <sys/buf.h>
+#include <sys/conf.h>
 #include <sys/kernel.h>
 #include <sys/lock.h>
 #include <sys/malloc.h>
@@ -51,6 +52,18 @@
 #include <sys/vnode.h>
 #include <sys/poll.h>
 
+#include <machine/limits.h>
+
+#include <vm/vm.h>
+#include <vm/vm_object.h>
+#include <vm/vm_extern.h>
+#include <vm/pmap.h>
+#include <vm/vm_map.h>
+#include <vm/vm_page.h>
+#include <vm/vm_pager.h>
+#include <vm/vnode_pager.h>
+#include <vm/vm_zone.h>
+
 static int vop_nostrategy __P((struct vop_strategy_args *));
 
 /*
@@ -67,7 +80,10 @@ static struct vnodeopv_entry_desc default_vnodeop_entries[] = {
 	{ &vop_advlock_desc,		(vop_t *) vop_einval },
 	{ &vop_bwrite_desc,		(vop_t *) vop_stdbwrite },
 	{ &vop_close_desc,		(vop_t *) vop_null },
+	{ &vop_createvobject_desc,	(vop_t *) vop_stdcreatevobject },
+	{ &vop_destroyvobject_desc,	(vop_t *) vop_stddestroyvobject },
 	{ &vop_fsync_desc,		(vop_t *) vop_null },
+	{ &vop_getvobject_desc,		(vop_t *) vop_stdgetvobject },
 	{ &vop_inactive_desc,		(vop_t *) vop_stdinactive },
 	{ &vop_ioctl_desc,		(vop_t *) vop_enotty },
 	{ &vop_islocked_desc,		(vop_t *) vop_noislocked },
@@ -522,6 +538,106 @@ vop_stdgetwritemount(ap)
 	return (0);
 }
 
+int
+vop_stdcreatevobject(ap)
+	struct vop_createvobject_args /* {
+		struct vnode *vp;
+		struct ucred *cred;
+		struct proc *p;
+	} */ *ap;
+{
+	struct vnode *vp = ap->a_vp;
+	struct ucred *cred = ap->a_cred;
+	struct proc *p = ap->a_p;
+	struct vattr vat;
+	vm_object_t object;
+	int error = 0;
+
+	if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE)
+		return (0);
+
+retry:
+	if ((object = vp->v_object) == NULL) {
+		if (vp->v_type == VREG || vp->v_type == VDIR) {
+			if ((error = VOP_GETATTR(vp, &vat, cred, p)) != 0)
+				goto retn;
+			object = vnode_pager_alloc(vp, vat.va_size, 0, 0);
+		} else if (devsw(vp->v_rdev) != NULL) {
+			/*
+			 * This simply allocates the biggest object possible
+			 * for a disk vnode.  This should be fixed, but doesn't
+			 * cause any problems (yet).
+			 */
+			object = vnode_pager_alloc(vp, IDX_TO_OFF(INT_MAX), 0, 0);
+		} else {
+			goto retn;
+		}
+		/*
+		 * Dereference the reference we just created.  This assumes
+		 * that the object is associated with the vp.
+		 */
+		object->ref_count--;
+		vp->v_usecount--;
+	} else {
+		if (object->flags & OBJ_DEAD) {
+			VOP_UNLOCK(vp, 0, p);
+			tsleep(object, PVM, "vodead", 0);
+			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
+			goto retry;
+		}
+	}
+
+	KASSERT(vp->v_object != NULL, ("vfs_object_create: NULL object"));
+	vp->v_flag |= VOBJBUF;
+
+retn:
+	return (error);
+}
+
+int
+vop_stddestroyvobject(ap)
+	struct vop_destroyvobject_args /* {
+		struct vnode *vp;
+	} */ *ap;
+{
+	struct vnode *vp = ap->a_vp;
+	vm_object_t obj = vp->v_object;
+
+	if (vp->v_object == NULL)
+		return (0);
+
+	if (obj->ref_count == 0) {
+		/*
+		 * vclean() may be called twice. The first time
+		 * removes the primary reference to the object,
+		 * the second time goes one further and is a
+		 * special-case to terminate the object.
+		 */
+		vm_object_terminate(obj);
+	} else {
+		/*
+		 * Woe to the process that tries to page now :-).
+		 */
+		vm_pager_deallocate(obj);
+	}
+	return (0);
+}
+
+int
+vop_stdgetvobject(ap)
+	struct vop_getvobject_args /* {
+		struct vnode *vp;
+		struct vm_object **objpp;
+	} */ *ap;
+{
+	struct vnode *vp = ap->a_vp;
+	struct vm_object **objpp = ap->a_objpp;
+
+	if (objpp)
+		*objpp = vp->v_object;
+	return (vp->v_object ? 0 : EINVAL);
+}
+
 /* 
  * vfs default ops
  * used to fill the vfs fucntion table to get reasonable default return values.
diff --git a/sys/kern/vfs_export.c b/sys/kern/vfs_export.c
index 52ad0ef..bebc3c9 100644
--- a/sys/kern/vfs_export.c
+++ b/sys/kern/vfs_export.c
@@ -484,10 +484,9 @@ getnewvnode(tag, mp, vops, vpp)
 		 * if it still has cached pages or we cannot get
 		 * its interlock.
 		 */
-		object = vp->v_object;
 		if (LIST_FIRST(&vp->v_cache_src) != NULL ||
-		    (object && (object->resident_page_count ||
-		     object->ref_count)) ||
+		    (VOP_GETVOBJECT(vp, &object) == 0 &&
+		     (object->resident_page_count || object->ref_count)) ||
 		    !simple_lock_try(&vp->v_interlock)) {
 			TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
 			vp = NULL;
@@ -711,8 +710,7 @@ vinvalbuf(vp, flags, cred, p, slpflag, slptimeo)
 	 * Destroy the copy in the VM cache, too.
 	 */
 	simple_lock(&vp->v_interlock);
-	object = vp->v_object;
-	if (object != NULL) {
+	if (VOP_GETVOBJECT(vp, &object) == 0) {
 		vm_object_page_remove(object, 0, 0,
 			(flags & V_SAVE) ? TRUE : FALSE);
 	}
@@ -1649,7 +1647,6 @@ vclean(vp, flags, p)
 	struct proc *p;
 {
 	int active;
-	vm_object_t obj;
 
 	/*
 	 * Check to see if the vnode is in use. If so we have to reference it
@@ -1686,22 +1683,7 @@ vclean(vp, flags, p)
 			vinvalbuf(vp, 0, NOCRED, p, 0, 0);
 	}
 
-	if ((obj = vp->v_object) != NULL) {
-		if (obj->ref_count == 0) {
-			/*
-			 * vclean() may be called twice. The first time
-			 * removes the primary reference to the object,
-			 * the second time goes one further and is a
-			 * special-case to terminate the object.
-			 */
-			vm_object_terminate(obj);
-		} else {
-			/*
-			 * Woe to the process that tries to page now :-).
-			 */
-			vm_pager_deallocate(obj);
-		}
-	}
+	VOP_DESTROYVOBJECT(vp);
 
 	/*
 	 * If purging an active vnode, it must be closed and
@@ -2523,20 +2505,20 @@ loop:
 			continue;
 
 		if (flags != MNT_WAIT) {
-			obj = vp->v_object;
-			if (obj == NULL || (obj->flags & OBJ_MIGHTBEDIRTY) == 0)
+			if (VOP_GETVOBJECT(vp, &obj) != 0 ||
+			    (obj->flags & OBJ_MIGHTBEDIRTY) == 0)
 				continue;
 			if (VOP_ISLOCKED(vp, NULL))
 				continue;
 		}
 
 		simple_lock(&vp->v_interlock);
-		if (vp->v_object &&
-		   (vp->v_object->flags & OBJ_MIGHTBEDIRTY)) {
+		if (VOP_GETVOBJECT(vp, &obj) == 0 &&
+		    (obj->flags & OBJ_MIGHTBEDIRTY)) {
 			if (!vget(vp,
 				LK_INTERLOCK | LK_EXCLUSIVE | LK_RETRY | LK_NOOBJ, curproc)) {
-				if (vp->v_object) {
-					vm_object_page_clean(vp->v_object, 0, 0, flags == MNT_WAIT ? OBJPC_SYNC : OBJPC_NOSYNC);
+				if (VOP_GETVOBJECT(vp, &obj) == 0) {
+					vm_object_page_clean(obj, 0, 0, flags == MNT_WAIT ? OBJPC_SYNC : OBJPC_NOSYNC);
 					anyio = 1;
 				}
 				vput(vp);
@@ -2563,49 +2545,7 @@ vfs_object_create(vp, p, cred)
 	struct proc *p;
 	struct ucred *cred;
 {
-	struct vattr vat;
-	vm_object_t object;
-	int error = 0;
-
-	if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE)
-		return 0;
-
-retry:
-	if ((object = vp->v_object) == NULL) {
-		if (vp->v_type == VREG || vp->v_type == VDIR) {
-			if ((error = VOP_GETATTR(vp, &vat, cred, p)) != 0)
-				goto retn;
-			object = vnode_pager_alloc(vp, vat.va_size, 0, 0);
-		} else if (devsw(vp->v_rdev) != NULL) {
-			/*
-			 * This simply allocates the biggest object possible
-			 * for a disk vnode.  This should be fixed, but doesn't
-			 * cause any problems (yet).
-			 */
-			object = vnode_pager_alloc(vp, IDX_TO_OFF(INT_MAX), 0, 0);
-		} else {
-			goto retn;
-		}
-		/*
-		 * Dereference the reference we just created.  This assumes
-		 * that the object is associated with the vp.
-		 */
-		object->ref_count--;
-		vp->v_usecount--;
-	} else {
-		if (object->flags & OBJ_DEAD) {
-			VOP_UNLOCK(vp, 0, p);
-			tsleep(object, PVM, "vodead", 0);
-			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
-			goto retry;
-		}
-	}
-
-	KASSERT(vp->v_object != NULL, ("vfs_object_create: NULL object"));
-	vp->v_flag |= VOBJBUF;
-
-retn:
-	return error;
+	return (VOP_CREATEVOBJECT(vp, cred, p));
 }
 
 void
diff --git a/sys/kern/vfs_extattr.c b/sys/kern/vfs_extattr.c
index 7f4c6bc0..4064fa3 100644
--- a/sys/kern/vfs_extattr.c
+++ b/sys/kern/vfs_extattr.c
@@ -1068,7 +1068,7 @@ open(p, uap)
 			goto bad;
 	}
 	/* assert that vn_open created a backing object if one is needed */
-	KASSERT(!vn_canvmio(vp) || vp->v_object != NULL,
+	KASSERT(!vn_canvmio(vp) || VOP_GETVOBJECT(vp, NULL) == 0,
 		("open: vmio vnode has no backing object after vn_open"));
 	p->p_retval[0] = indx;
 	return (0);
@@ -2637,6 +2637,7 @@ fsync(p, uap)
 	struct vnode *vp;
 	struct mount *mp;
 	struct file *fp;
+	vm_object_t obj;
 	int error;
 
 	if ((error = getvnode(p->p_fd, SCARG(uap, fd), &fp)) != 0)
@@ -2645,8 +2646,8 @@ fsync(p, uap)
 	if ((error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0)
 		return (error);
 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
-	if (vp->v_object)
-		vm_object_page_clean(vp->v_object, 0, 0, 0);
+	if (VOP_GETVOBJECT(vp, &obj) == 0)
+		vm_object_page_clean(obj, 0, 0, 0);
 	error = VOP_FSYNC(vp, fp->f_cred, MNT_WAIT, p);
 #ifdef SOFTUPDATES
 	if (error == 0 && vp->v_mount && (vp->v_mount->mnt_flag & MNT_SOFTDEP))
@@ -3415,7 +3416,7 @@ fhopen(p, uap)
 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
 		fp->f_flag |= FHASLOCK;
 	}
-	if ((vp->v_type == VREG) && (vp->v_object == NULL))
+	if ((vp->v_type == VREG) && (VOP_GETVOBJECT(vp, NULL) != 0))
 		vfs_object_create(vp, p, p->p_ucred);
 
 	VOP_UNLOCK(vp, 0, p);
diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
index 52ad0ef..bebc3c9 100644
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -484,10 +484,9 @@ getnewvnode(tag, mp, vops, vpp)
 		 * if it still has cached pages or we cannot get
 		 * its interlock.
 		 */
-		object = vp->v_object;
 		if (LIST_FIRST(&vp->v_cache_src) != NULL ||
-		    (object && (object->resident_page_count ||
-		     object->ref_count)) ||
+		    (VOP_GETVOBJECT(vp, &object) == 0 &&
+		     (object->resident_page_count || object->ref_count)) ||
 		    !simple_lock_try(&vp->v_interlock)) {
 			TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
 			vp = NULL;
@@ -711,8 +710,7 @@ vinvalbuf(vp, flags, cred, p, slpflag, slptimeo)
 	 * Destroy the copy in the VM cache, too.
 	 */
 	simple_lock(&vp->v_interlock);
-	object = vp->v_object;
-	if (object != NULL) {
+	if (VOP_GETVOBJECT(vp, &object) == 0) {
 		vm_object_page_remove(object, 0, 0,
 			(flags & V_SAVE) ? TRUE : FALSE);
 	}
@@ -1649,7 +1647,6 @@ vclean(vp, flags, p)
 	struct proc *p;
 {
 	int active;
-	vm_object_t obj;
 
 	/*
 	 * Check to see if the vnode is in use. If so we have to reference it
@@ -1686,22 +1683,7 @@ vclean(vp, flags, p)
 			vinvalbuf(vp, 0, NOCRED, p, 0, 0);
 	}
 
-	if ((obj = vp->v_object) != NULL) {
-		if (obj->ref_count == 0) {
-			/*
-			 * vclean() may be called twice. The first time
-			 * removes the primary reference to the object,
-			 * the second time goes one further and is a
-			 * special-case to terminate the object.
-			 */
-			vm_object_terminate(obj);
-		} else {
-			/*
-			 * Woe to the process that tries to page now :-).
-			 */
-			vm_pager_deallocate(obj);
-		}
-	}
+	VOP_DESTROYVOBJECT(vp);
 
 	/*
 	 * If purging an active vnode, it must be closed and
@@ -2523,20 +2505,20 @@ loop:
 			continue;
 
 		if (flags != MNT_WAIT) {
-			obj = vp->v_object;
-			if (obj == NULL || (obj->flags & OBJ_MIGHTBEDIRTY) == 0)
+			if (VOP_GETVOBJECT(vp, &obj) != 0 ||
+			    (obj->flags & OBJ_MIGHTBEDIRTY) == 0)
 				continue;
 			if (VOP_ISLOCKED(vp, NULL))
 				continue;
 		}
 
 		simple_lock(&vp->v_interlock);
-		if (vp->v_object &&
-		   (vp->v_object->flags & OBJ_MIGHTBEDIRTY)) {
+		if (VOP_GETVOBJECT(vp, &obj) == 0 &&
+		    (obj->flags & OBJ_MIGHTBEDIRTY)) {
 			if (!vget(vp,
 				LK_INTERLOCK | LK_EXCLUSIVE | LK_RETRY | LK_NOOBJ, curproc)) {
-				if (vp->v_object) {
-					vm_object_page_clean(vp->v_object, 0, 0, flags == MNT_WAIT ? OBJPC_SYNC : OBJPC_NOSYNC);
+				if (VOP_GETVOBJECT(vp, &obj) == 0) {
+					vm_object_page_clean(obj, 0, 0, flags == MNT_WAIT ? OBJPC_SYNC : OBJPC_NOSYNC);
 					anyio = 1;
 				}
 				vput(vp);
@@ -2563,49 +2545,7 @@ vfs_object_create(vp, p, cred)
 	struct proc *p;
 	struct ucred *cred;
 {
-	struct vattr vat;
-	vm_object_t object;
-	int error = 0;
-
-	if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE)
-		return 0;
-
-retry:
-	if ((object = vp->v_object) == NULL) {
-		if (vp->v_type == VREG || vp->v_type == VDIR) {
-			if ((error = VOP_GETATTR(vp, &vat, cred, p)) != 0)
-				goto retn;
-			object = vnode_pager_alloc(vp, vat.va_size, 0, 0);
-		} else if (devsw(vp->v_rdev) != NULL) {
-			/*
-			 * This simply allocates the biggest object possible
-			 * for a disk vnode.  This should be fixed, but doesn't
-			 * cause any problems (yet).
-			 */
-			object = vnode_pager_alloc(vp, IDX_TO_OFF(INT_MAX), 0, 0);
-		} else {
-			goto retn;
-		}
-		/*
-		 * Dereference the reference we just created.  This assumes
-		 * that the object is associated with the vp.
-		 */
-		object->ref_count--;
-		vp->v_usecount--;
-	} else {
-		if (object->flags & OBJ_DEAD) {
-			VOP_UNLOCK(vp, 0, p);
-			tsleep(object, PVM, "vodead", 0);
-			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
-			goto retry;
-		}
-	}
-
-	KASSERT(vp->v_object != NULL, ("vfs_object_create: NULL object"));
-	vp->v_flag |= VOBJBUF;
-
-retn:
-	return error;
+	return (VOP_CREATEVOBJECT(vp, cred, p));
 }
 
 void
diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c
index 7f4c6bc0..4064fa3 100644
--- a/sys/kern/vfs_syscalls.c
+++ b/sys/kern/vfs_syscalls.c
@@ -1068,7 +1068,7 @@ open(p, uap)
 			goto bad;
 	}
 	/* assert that vn_open created a backing object if one is needed */
-	KASSERT(!vn_canvmio(vp) || vp->v_object != NULL,
+	KASSERT(!vn_canvmio(vp) || VOP_GETVOBJECT(vp, NULL) == 0,
 		("open: vmio vnode has no backing object after vn_open"));
 	p->p_retval[0] = indx;
 	return (0);
@@ -2637,6 +2637,7 @@ fsync(p, uap)
 	struct vnode *vp;
 	struct mount *mp;
 	struct file *fp;
+	vm_object_t obj;
 	int error;
 
 	if ((error = getvnode(p->p_fd, SCARG(uap, fd), &fp)) != 0)
@@ -2645,8 +2646,8 @@ fsync(p, uap)
 	if ((error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0)
 		return (error);
 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
-	if (vp->v_object)
-		vm_object_page_clean(vp->v_object, 0, 0, 0);
+	if (VOP_GETVOBJECT(vp, &obj) == 0)
+		vm_object_page_clean(obj, 0, 0, 0);
 	error = VOP_FSYNC(vp, fp->f_cred, MNT_WAIT, p);
 #ifdef SOFTUPDATES
 	if (error == 0 && vp->v_mount && (vp->v_mount->mnt_flag & MNT_SOFTDEP))
@@ -3415,7 +3416,7 @@ fhopen(p, uap)
 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
 		fp->f_flag |= FHASLOCK;
 	}
-	if ((vp->v_type == VREG) && (vp->v_object == NULL))
+	if ((vp->v_type == VREG) && (VOP_GETVOBJECT(vp, NULL) != 0))
 		vfs_object_create(vp, p, p->p_ucred);
 
 	VOP_UNLOCK(vp, 0, p);
diff --git a/sys/kern/vnode_if.src b/sys/kern/vnode_if.src
index 9ccba54..7a6d8ae 100644
--- a/sys/kern/vnode_if.src
+++ b/sys/kern/vnode_if.src
@@ -555,3 +555,27 @@ vop_setextattr {
 	IN struct ucred *cred;
 	IN struct proc *p;
 };
+
+#
+#% createvobject	vp	L L L
+#
+vop_createvobject {
+	IN struct vnode *vp;
+	IN struct ucred *cred;
+	IN struct proc *p;
+};
+
+#
+#% destroyvobject	vp	L L L
+#
+vop_destroyvobject {
+	IN struct vnode *vp;
+};
+
+#
+#% getvobject	vp	L L L
+#
+vop_getvobject {
+	IN struct vnode *vp;
+	OUT struct vm_object **objpp;
+};
diff --git a/sys/sys/vnode.h b/sys/sys/vnode.h
index 08de778..41ca09b 100644
--- a/sys/sys/vnode.h
+++ b/sys/sys/vnode.h
@@ -629,6 +629,9 @@ int	vop_enotty __P((struct vop_generic_args *ap));
 int	vop_defaultop __P((struct vop_generic_args *ap));
 int	vop_null __P((struct vop_generic_args *ap));
 int	vop_panic __P((struct vop_generic_args *ap));
+int	vop_stdcreatevobject __P((struct vop_createvobject_args *ap));
+int	vop_stddestroyvobject __P((struct vop_destroyvobject_args *ap));
+int	vop_stdgetvobject __P((struct vop_getvobject_args *ap));
 
 void	vfree __P((struct vnode *));
 void 	vput __P((struct vnode *vp));
diff --git a/sys/vm/vm_mmap.c b/sys/vm/vm_mmap.c
index 79b6b72..43d75a5 100644
--- a/sys/vm/vm_mmap.c
+++ b/sys/vm/vm_mmap.c
@@ -198,6 +198,7 @@ mmap(p, uap)
 	int disablexworkaround;
 	off_t pos;
 	struct vmspace *vms = p->p_vmspace;
+	vm_object_t obj;
 
 	addr = (vm_offset_t) uap->addr;
 	size = uap->len;
@@ -295,6 +296,14 @@ mmap(p, uap)
 		vp = (struct vnode *) fp->f_data;
 		if (vp->v_type != VREG && vp->v_type != VCHR)
 			return (EINVAL);
+		if (vp->v_type == VREG) {
+			/*
+			 * Get the proper underlying object
+			 */
+			if (VOP_GETVOBJECT(vp, &obj) != 0)
+				return (EINVAL);
+			vp = (struct vnode*)obj->handle;
+		}
 		/*
 		 * XXX hack to handle use of /dev/zero to map anon memory (ala
 		 * SunOS).