VFS Lite2 Changes

1 files changed, 1018 insertions, 212 deletions

diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
index 10ed04c26ca..f265b15051d 100644
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vfs_subr.c,v 1.10 1997/04/25 09:33:24 deraadt Exp $	*/
+/*	$OpenBSD: vfs_subr.c,v 1.11 1997/10/06 15:12:42 csapuntz Exp $	*/
 /*	$NetBSD: vfs_subr.c,v 1.53 1996/04/22 01:39:13 christos Exp $	*/
 
 /*
@@ -51,6 +51,7 @@
 #include <sys/mount.h>
 #include <sys/time.h>
 #include <sys/fcntl.h>
+#include <sys/kernel.h>
 #include <sys/vnode.h>
 #include <sys/stat.h>
 #include <sys/namei.h>
@@ -88,8 +89,28 @@ int suid_clear = 1;		/* 1 => clear SUID / SGID on owner change */
 	LIST_REMOVE(bp, b_vnbufs);					\
 	(bp)->b_vnbufs.le_next = NOLIST;				\
 }  
-TAILQ_HEAD(freelst, vnode) vnode_free_list;	/* vnode free list */
+
+struct freelst vnode_hold_list;   /* list of vnodes referencing buffers */
+struct freelst vnode_free_list;   /* vnode free list */
+
 struct mntlist mountlist;			/* mounted filesystem list */
+struct simplelock mountlist_slock;
+static struct simplelock mntid_slock;
+struct simplelock mntvnode_slock;
+struct simplelock vnode_free_list_slock;
+static struct simplelock spechash_slock;
+
+/*
+ * The workitem queue.
+  */ 
+#define SYNCER_MAXDELAY       32
+int syncer_maxdelay = SYNCER_MAXDELAY;        /* maximum delay time */
+time_t syncdelay = 30;                        /* time to delay syncing vnodes */
+ 
+static int syncer_delayno = 0;
+static long syncer_mask;
+LIST_HEAD(synclist, vnode);
+static struct synclist *syncer_workitem_pending;
 
 int vfs_lock __P((struct mount *));
 void vfs_unlock __P((struct mount *));
@@ -107,15 +128,16 @@ int bdevvp __P((dev_t, struct vnode **));
 int cdevvp __P((dev_t, struct vnode **));
 int getdevvp __P((dev_t, struct vnode **, enum vtype));
 struct vnode *checkalias __P((struct vnode *, dev_t, struct mount *));
-int vget __P((struct vnode *, int));
 void vref __P((struct vnode *));
 void vput __P((struct vnode *));
 void vrele __P((struct vnode *));
+int vunref __P((struct vnode *));
 void vhold __P((struct vnode *));
 void holdrele __P((struct vnode *));
 int vflush __P((struct mount *, struct vnode *, int));
 void vgoneall __P((struct vnode *));
 void vgone __P((struct vnode *));
+void vgonel __P((struct vnode *, struct proc *));
 int vcount __P((struct vnode *));
 void vprint __P((char *, struct vnode *));
 int vfs_mountedon __P((struct vnode *));
@@ -126,10 +148,10 @@ int vaccess __P((mode_t, uid_t, gid_t, mode_t, struct ucred *));
 void vfs_unmountall __P((void));
 void vfs_shutdown __P((void));
 
-static int vfs_hang_addrlist __P((struct mount *, struct netexport *,
+int vfs_hang_addrlist __P((struct mount *, struct netexport *,
 				  struct export_args *));
-static int vfs_free_netcred __P((struct radix_node *, void *));
-static void vfs_free_addrlist __P((struct netexport *));
+int vfs_free_netcred __P((struct radix_node *, void *));
+void vfs_free_addrlist __P((struct netexport *));
 
 #ifdef DEBUG
 void printlockedvnodes __P((void));
@@ -142,124 +164,191 @@ void
 vntblinit()
 {
 
+	simple_lock_init(&mntvnode_slock);
+	simple_lock_init(&mntid_slock);
+	simple_lock_init(&spechash_slock);
+	TAILQ_INIT(&vnode_hold_list);
 	TAILQ_INIT(&vnode_free_list);
+	simple_lock_init(&vnode_free_list_slock);
 	CIRCLEQ_INIT(&mountlist);
+	/*
+	 * Initialize the filesystem syncer.
+	 */
+	syncer_workitem_pending = hashinit(syncer_maxdelay, M_VNODE,
+					   &syncer_mask);
+	syncer_maxdelay = syncer_mask + 1;
+
 }
 
+
 /*
- * Lock a filesystem.
- * Used to prevent access to it while mounting and unmounting.
+ * Mark a mount point as busy. Used to synchornize access and to delay
+ * unmounting. Interlock is not released n failure.
  */
+
 int
-vfs_lock(mp)
-	register struct mount *mp;
+vfs_busy(mp, flags, interlkp, p)
+	struct mount *mp;
+	int flags;
+	struct simplelock *interlkp;
+	struct proc *p;
 {
+	int lkflags;
 
-	while (mp->mnt_flag & MNT_MLOCK) {
+	if (mp->mnt_flag & MNT_UNMOUNT) {
+		if (flags & LK_NOWAIT)
+			return (ENOENT);
 		mp->mnt_flag |= MNT_MWAIT;
-		tsleep((caddr_t)mp, PVFS, "vfslock", 0);
+		if (interlkp)
+			simple_unlock(interlkp);
+		/*
+		 * Since all busy locks are shared except the exclusive
+		 * lock granted when unmounting, the only place that a
+		 * wakeup needs to be done is at the release of the
+		 * exclusive lock at the end of dounmount.
+		 */
+ 		sleep((caddr_t)mp, PVFS);
+		if (interlkp)
+			simple_lock(interlkp);
+		return (ENOENT);
 	}
-	mp->mnt_flag |= MNT_MLOCK;
-	return (0);
+	lkflags = LK_SHARED;
+	if (interlkp)
+		lkflags |= LK_INTERLOCK;
+	if (lockmgr(&mp->mnt_lock, lkflags, interlkp, p))
+		panic("vfs_busy: unexpected lock failure");
+        return (0);
 }
 
+
 /*
- * Unlock a locked filesystem.
- * Panic if filesystem is not locked.
+ * Free a busy file system
  */
 void
-vfs_unlock(mp)
-	register struct mount *mp;
+vfs_unbusy(mp, p)
+	struct mount *mp;
+	struct proc *p;
 {
-
-	if ((mp->mnt_flag & MNT_MLOCK) == 0)
-		panic("vfs_unlock: not locked");
-	mp->mnt_flag &= ~MNT_MLOCK;
-	if (mp->mnt_flag & MNT_MWAIT) {
-		mp->mnt_flag &= ~MNT_MWAIT;
-		wakeup((caddr_t)mp);
-	}
+	lockmgr(&mp->mnt_lock, LK_RELEASE, NULL, p);
 }
 
 /*
- * Mark a mount point as busy.
- * Used to synchronize access and to delay unmounting.
+ * Lookup a filesystem type, and if found allocate and initialize
+ * a mount structure for it.
+ *
+ * Devname is usually updated by mount(8) after booting.
  */
-int
-vfs_busy(mp)
-	register struct mount *mp;
-{
 
-	while(mp->mnt_flag & MNT_MPBUSY) {
-		mp->mnt_flag |= MNT_MPWANT;
-		tsleep((caddr_t)&mp->mnt_flag, PVFS, "vfsbusy", 0);
-	}
-	if (mp->mnt_flag & MNT_UNMOUNT)
-		return (1);
-	mp->mnt_flag |= MNT_MPBUSY;
-	return (0);
-}
+int
+vfs_rootmountalloc(fstypename, devname, mpp)
+	char *fstypename;
+	char *devname;
+	struct mount **mpp;
+ {
+	struct proc *p = curproc;	/* XXX */
+	struct vfsconf *vfsp;
+	struct mount *mp;
+ 
+	for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
+		if (!strcmp(vfsp->vfc_name, fstypename))
+			break;
+	if (vfsp == NULL)
+		return (ENODEV);
+	mp = malloc((u_long)sizeof(struct mount), M_MOUNT, M_WAITOK);
+	bzero((char *)mp, (u_long)sizeof(struct mount));
+	lockinit(&mp->mnt_lock, PVFS, "vfslock", 0, 0);
+	(void)vfs_busy(mp, LK_NOWAIT, 0, p);
+	LIST_INIT(&mp->mnt_vnodelist);
+	mp->mnt_vfc = vfsp;
+	mp->mnt_op = vfsp->vfc_vfsops;
+	mp->mnt_flag = MNT_RDONLY;
+	mp->mnt_vnodecovered = NULLVP;
+	vfsp->vfc_refcount++;
+	mp->mnt_stat.f_type = vfsp->vfc_typenum;
+	mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK;
+	strncpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN);
+	mp->mnt_stat.f_mntonname[0] = '/';
+	(void) copystr(devname, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 0);
+	*mpp = mp;
+ 	return (0);
+ }
 
 /*
- * Free a busy filesystem.
- * Panic if filesystem is not busy.
- */
-void
-vfs_unbusy(mp)
-	register struct mount *mp;
+ * Find an appropriate filesystem to use for the root. If a filesystem
+ * has not been preselected, walk through the list of known filesystems
+ * trying those that have mountroot routines, and try them until one
+ * works or we have tried them all.
+  */
+int
+vfs_mountroot()
 {
-
-	if ((mp->mnt_flag & MNT_MPBUSY) == 0)
-		panic("vfs_unbusy: not busy");
-	mp->mnt_flag &= ~MNT_MPBUSY;
-	if (mp->mnt_flag & MNT_MPWANT) {
-		mp->mnt_flag &= ~MNT_MPWANT;
-		wakeup((caddr_t)&mp->mnt_flag);
-	}
+	struct vfsconf *vfsp;
+	extern int (*mountroot)(void);
+	int error;
+ 
+	if (mountroot != NULL)
+		return ((*mountroot)());
+	for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next) {
+		if (vfsp->vfc_mountroot == NULL)
+			continue;
+		if ((error = (*vfsp->vfc_mountroot)()) == 0)
+			return (0);
+		printf("%s_mountroot failed: %d\n", vfsp->vfc_name, error);
+ 	}
+	return (ENODEV);
 }
-
+ 
 /*
  * Lookup a mount point by filesystem identifier.
  */
 struct mount *
-getvfs(fsid)
+vfs_getvfs(fsid)
 	fsid_t *fsid;
 {
 	register struct mount *mp;
 
+	simple_lock(&mountlist_slock);
 	for (mp = mountlist.cqh_first; mp != (void *)&mountlist;
-	     mp = mp->mnt_list.cqe_next)
+	     mp = mp->mnt_list.cqe_next) {
 		if (mp->mnt_stat.f_fsid.val[0] == fsid->val[0] &&
-		    mp->mnt_stat.f_fsid.val[1] == fsid->val[1])
+		    mp->mnt_stat.f_fsid.val[1] == fsid->val[1]) {
+			simple_unlock(&mountlist_slock);
 			return (mp);
+		}
+	}
+	simple_unlock(&mountlist_slock);
 	return ((struct mount *)0);
 }
 
+
 /*
  * Get a new unique fsid
  */
 void
-getnewfsid(mp, mtype)
+vfs_getnewfsid(mp)
 	struct mount *mp;
-	int mtype;
 {
 	static u_short xxxfs_mntid;
 
 	fsid_t tfsid;
+	int mtype;
 
-	mp->mnt_stat.f_fsid.val[0] = makedev(nblkdev + 11, 0);	/* XXX */
+	simple_lock(&mntid_slock);
+	mtype = mp->mnt_vfc->vfc_typenum;
+	mp->mnt_stat.f_fsid.val[0] = makedev(nblkdev + mtype, 0);
 	mp->mnt_stat.f_fsid.val[1] = mtype;
 	if (xxxfs_mntid == 0)
 		++xxxfs_mntid;
-	tfsid.val[0] = makedev((nblkdev + mtype) & 0xff, xxxfs_mntid);
+	tfsid.val[0] = makedev(nblkdev + mtype, xxxfs_mntid);
 	tfsid.val[1] = mtype;
 	if (mountlist.cqh_first != (void *)&mountlist) {
-		while (getvfs(&tfsid)) {
+		while (vfs_getvfs(&tfsid)) {
 			tfsid.val[0]++;
 			xxxfs_mntid++;
 		}
 	}
 	mp->mnt_stat.f_fsid.val[0] = tfsid.val[0];
+	simple_unlock(&mntid_slock);
 }
 
 /*
@@ -318,20 +407,56 @@ getnewvnode(tag, mp, vops, vpp)
 	int (**vops) __P((void *));
 	struct vnode **vpp;
 {
-	register struct vnode *vp;
+	struct proc *p = curproc;			/* XXX */
+	struct freelst *listhd;
+	static int toggle;
+	struct vnode *vp;
 #ifdef DIAGNOSTIC
 	int s;
 #endif
 
-	if ((vnode_free_list.tqh_first == NULL &&
-	     numvnodes < 2 * desiredvnodes) ||
-	    numvnodes < desiredvnodes) {
+	/*
+	 * We must choose whether to allocate a new vnode or recycle an
+	 * existing one. The criterion for allocating a new one is that
+	 * the total number of vnodes is less than the number desired or
+	 * there are no vnodes on either free list. Generally we only
+	 * want to recycle vnodes that have no buffers associated with
+	 * them, so we look first on the vnode_free_list. If it is empty,
+	 * we next consider vnodes with referencing buffers on the
+	 * vnode_hold_list. The toggle ensures that half the time we
+	 * will use a buffer from the vnode_hold_list, and half the time
+	 * we will allocate a new one unless the list has grown to twice
+	 * the desired size. We are reticent to recycle vnodes from the
+	 * vnode_hold_list because we will lose the identity of all its
+	 * referencing buffers.
+	 */
+	toggle ^= 1;
+	if (numvnodes > 2 * desiredvnodes)
+		toggle = 0;
+
+
+	simple_lock(&vnode_free_list_slock);
+	if ((numvnodes < desiredvnodes) ||
+	    ((TAILQ_FIRST(listhd = &vnode_free_list) == NULL) &&
+	     ((TAILQ_FIRST(listhd = &vnode_hold_list) == NULL) || toggle))) {
+		simple_unlock(&vnode_free_list_slock);
 		vp = (struct vnode *)malloc((u_long)sizeof *vp,
 		    M_VNODE, M_WAITOK);
 		bzero((char *)vp, sizeof *vp);
 		numvnodes++;
 	} else {
-		if ((vp = vnode_free_list.tqh_first) == NULL) {
+		for (vp = TAILQ_FIRST(listhd); vp != NULLVP;
+		     vp = TAILQ_NEXT(vp, v_freelist)) {
+			if (simple_lock_try(&vp->v_interlock))
+				break;
+		}
+		/*
+		 * Unless this is a bad time of the month, at most
+		 * the first NCPUS items on the free list are
+		 * locked, so this is close enough to being empty.
+		 */
+		if (vp == NULLVP) {
+			simple_unlock(&vnode_free_list_slock);
 			tablefull("vnode");
 			*vpp = 0;
 			return (ENFILE);
@@ -340,12 +465,15 @@ getnewvnode(tag, mp, vops, vpp)
 			vprint("free vnode", vp);
 			panic("free vnode isn't");
 		}
-		TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
+		TAILQ_REMOVE(listhd, vp, v_freelist);
 		/* see comment on why 0xdeadb is set at end of vgone (below) */
-		vp->v_freelist.tqe_prev = (struct vnode **)0xdeadb;
+		vp->v_flag |= VGONEHACK;
+		simple_unlock(&vnode_free_list_slock);
 		vp->v_lease = NULL;
 		if (vp->v_type != VBAD)
-			vgone(vp);
+			vgonel(vp, p);
+		else
+			simple_unlock(&vp->v_interlock);
 #ifdef DIAGNOSTIC
 		if (vp->v_data) {
 			vprint("cleaned vnode", vp);
@@ -385,18 +513,19 @@ insmntque(vp, mp)
 	register struct vnode *vp;
 	register struct mount *mp;
 {
-
+	simple_lock(&mntvnode_slock);
 	/*
 	 * Delete from old mount point vnode list, if on one.
 	 */
+	
 	if (vp->v_mount != NULL)
 		LIST_REMOVE(vp, v_mntvnodes);
 	/*
 	 * Insert into list of vnodes for the new mount point, if available.
 	 */
-	if ((vp->v_mount = mp) == NULL)
-		return;
-	LIST_INSERT_HEAD(&mp->mnt_vnodelist, vp, v_mntvnodes);
+	if ((vp->v_mount = mp) != NULL)
+		LIST_INSERT_HEAD(&mp->mnt_vnodelist, vp, v_mntvnodes);
+	simple_unlock(&mntvnode_slock);
 }
 
 /*
@@ -435,14 +564,15 @@ vinvalbuf(vp, flags, cred, p, slpflag, slptimeo)
 	struct buf *nbp, *blist;
 	int s, error;
 
-	if (flags & V_SAVE) {
+	if ((flags & V_SAVE) && vp->v_dirtyblkhd.lh_first != NULL) {
 		if ((error = VOP_FSYNC(vp, cred, MNT_WAIT, p)) != 0)
 			return (error);
 		if (vp->v_dirtyblkhd.lh_first != NULL)
 			panic("vinvalbuf: dirty bufs");
 	}
 	for (;;) {
-		if ((blist = vp->v_cleanblkhd.lh_first) && flags & V_SAVEMETA)
+		if ((blist = vp->v_cleanblkhd.lh_first) && 
+		    (flags & V_SAVEMETA))
 			while (blist && blist->b_lblkno < 0)
 				blist = blist->b_vnbufs.le_next;
 		if (!blist && (blist = vp->v_dirtyblkhd.lh_first) &&
@@ -562,30 +692,140 @@ brelvp(bp)
 	register struct buf *bp;
 {
 	struct vnode *vp;
+	struct buf *wasdirty;
 
-	if (bp->b_vp == (struct vnode *) 0)
+	if ((vp = bp->b_vp) == (struct vnode *) 0)
 		panic("brelvp: NULL");
 	/*
 	 * Delete from old vnode list, if on one.
 	 */
+	wasdirty = vp->v_dirtyblkhd.lh_first;
 	if (bp->b_vnbufs.le_next != NOLIST)
 		bufremvn(bp);
-	vp = bp->b_vp;
+	if (wasdirty && LIST_FIRST(&vp->v_dirtyblkhd) == NULL)
+		LIST_REMOVE(vp, v_synclist);
 	bp->b_vp = (struct vnode *) 0;
 	HOLDRELE(vp);
 }
 
 /*
- * Reassign a buffer from one vnode to another.
- * Used to assign file specific control information
- * (indirect blocks) to the vnode to which they belong.
+ * The workitem queue.
+ * 
+ * It is useful to delay writes of file data and filesystem metadata
+ * for tens of seconds so that quickly created and deleted files need
+ * not waste disk bandwidth being created and removed. To realize this,
+ * we append vnodes to a "workitem" queue. When running with a soft
+ * updates implementation, most pending metadata dependencies should
+ * not wait for more than a few seconds. Thus, mounted on block devices
+ * are delayed only about a half the time that file data is delayed.
+ * Similarly, directory updates are more critical, so are only delayed
+ * about a third the time that file data is delayed. Thus, there are
+ * SYNCER_MAXDELAY queues that are processed round-robin at a rate of
+ * one each second (driven off the filesystem syner process). The
+ * syncer_delayno variable indicates the next queue that is to be processed.
+ * Items that need to be processed soon are placed in this queue:
+ *
+ *	syncer_workitem_pending[syncer_delayno]
+ *
+ * A delay of fifteen seconds is done by placing the request fifteen
+ * entries later in the queue:
+ *
+ *	syncer_workitem_pending[(syncer_delayno + 15) & syncer_mask]
+ *
+ */
+
+/*
+ * Add an item to the syncer work queue.
+ */
+void
+vn_syncer_add_to_worklist(vp, delay)
+	struct vnode *vp;
+	int delay;
+{
+	int s, slot;
+
+	s = splbio();
+	if (delay > syncer_maxdelay - 2)
+		delay = syncer_maxdelay - 2;
+	slot = (syncer_delayno + delay) & syncer_mask;
+	LIST_INSERT_HEAD(&syncer_workitem_pending[slot], vp, v_synclist);
+	splx(s);
+}
+
+/*
+ * System filesystem synchronizer daemon.
+ */
+
+extern int lbolt;
+
+void 
+sched_sync(p)
+	struct proc *p;
+{
+	struct synclist *slp;
+	struct vnode *vp;
+	long starttime;
+	int s;
+
+	for (;;) {
+		starttime = time.tv_sec;
+
+		/*
+		 * Push files whose dirty time has expired.
+		 */
+		s = splbio();
+		slp = &syncer_workitem_pending[syncer_delayno];
+		syncer_delayno += 1;
+		if (syncer_delayno == syncer_maxdelay)
+			syncer_delayno = 0;
+		splx(s);
+		while ((vp = LIST_FIRST(slp)) != NULL) {
+			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
+			(void) VOP_FSYNC(vp, p->p_ucred, MNT_LAZY, p);
+			VOP_UNLOCK(vp, 0, p);
+			if (LIST_FIRST(slp) == vp) {
+				if (LIST_FIRST(&vp->v_dirtyblkhd) == NULL)
+					panic("sched_sync: fsync failed");
+				/*
+				 * Move ourselves to the back of the sync list.
+				 */
+				LIST_REMOVE(vp, v_synclist);
+				vn_syncer_add_to_worklist(vp, syncdelay);
+			}
+		}
+
+		/*
+		 * Do soft update processing.
+		 */
+		if (bioops.io_sync)
+			(*bioops.io_sync)(NULL);
+
+		/*
+		 * If it has taken us less than a second to process the
+		 * current work, then wait. Otherwise start right over
+		 * again. We can still lose time if any single round
+		 * takes more than two seconds, but it does not really
+		 * matter as we are just trying to generally pace the
+		 * filesystem activity.
+		 */
+		if (time.tv_sec == starttime)
+			tsleep(&lbolt, PPAUSE, "syncer", 0);
+	}
+}
+
+/*
+ * Reassign a buffer from one vnode to another. Used to assign buffers
+ * to the appropriate clean or dirty list and to add newly dirty vnodes
+ * to the appropriate filesystem syncer list.
  */
 void
 reassignbuf(bp, newvp)
 	register struct buf *bp;
 	register struct vnode *newvp;
 {
-	register struct buflists *listheadp;
+	struct buflists *listheadp;
+	struct buf *wasdirty;
+	int delay;
 
 	if (newvp == NULL) {
 		printf("reassignbuf: NULL");
@@ -594,16 +834,36 @@ reassignbuf(bp, newvp)
 	/*
 	 * Delete from old vnode list, if on one.
 	 */
+	wasdirty = newvp->v_dirtyblkhd.lh_first;
 	if (bp->b_vnbufs.le_next != NOLIST)
 		bufremvn(bp);
 	/*
 	 * If dirty, put on list of dirty buffers;
 	 * otherwise insert onto list of clean buffers.
 	 */
-	if (bp->b_flags & B_DELWRI)
-		listheadp = &newvp->v_dirtyblkhd;
-	else
+	if ((bp->b_flags & B_DELWRI) == 0) {
 		listheadp = &newvp->v_cleanblkhd;
+		if (wasdirty && LIST_FIRST(&newvp->v_dirtyblkhd) == NULL)
+			LIST_REMOVE(newvp, v_synclist);
+	} else {
+		listheadp = &newvp->v_dirtyblkhd;
+		if (LIST_FIRST(listheadp) == NULL) {
+			switch (newvp->v_type) {
+			case VDIR:
+				delay = syncdelay / 3;
+				break;
+			case VBLK:
+				if (newvp->v_specmountpoint != NULL) {
+					delay = syncdelay / 2;
+					break;
+				}
+				/* fall through */
+			default:
+				delay = syncdelay;
+			}
+			vn_syncer_add_to_worklist(newvp, delay);
+		}
+	}
 	bufinsvn(bp, listheadp);
 }
 
@@ -649,8 +909,10 @@ getdevvp(dev, vpp, type)
 	struct vnode *nvp;
 	int error;
 
-	if (dev == NODEV)
+	if (dev == NODEV) {
+		*vpp = NULLVP;
 		return (0);
+	}
 	error = getnewvnode(VT_NON, NULL, spec_vnodeop_p, &nvp);
 	if (error) {
 		*vpp = NULLVP;
@@ -680,6 +942,7 @@ checkalias(nvp, nvp_rdev, mp)
 	dev_t nvp_rdev;
 	struct mount *mp;
 {
+	struct proc *p = curproc;
 	register struct vnode *vp;
 	struct vnode **vpp;
 
@@ -688,18 +951,23 @@ checkalias(nvp, nvp_rdev, mp)
 
 	vpp = &speclisth[SPECHASH(nvp_rdev)];
 loop:
+	simple_lock(&spechash_slock);
 	for (vp = *vpp; vp; vp = vp->v_specnext) {
+		simple_lock(&vp->v_interlock);
 		if (nvp_rdev != vp->v_rdev || nvp->v_type != vp->v_type)
 			continue;
 		/*
 		 * Alias, but not in use, so flush it out.
 		 */
 		if (vp->v_usecount == 0) {
-			vgone(vp);
+			simple_unlock(&spechash_slock);
+			vgonel(vp, p);
 			goto loop;
 		}
-		if (vget(vp, 1))
+		if (vget(vp, LK_EXCLUSIVE | LK_INTERLOCK, p)) {
+			simple_unlock(&spechash_slock);
 			goto loop;
+		}
 		break;
 	}
 	if (vp == NULL || vp->v_tag != VT_NON || vp->v_type != VBLK) {
@@ -708,18 +976,21 @@ loop:
 		nvp->v_rdev = nvp_rdev;
 		nvp->v_hashchain = vpp;
 		nvp->v_specnext = *vpp;
-		nvp->v_specflags = 0;
+		nvp->v_specmountpoint = NULL;
 		nvp->v_speclockf = NULL;
+		simple_unlock(&spechash_slock);
 		*vpp = nvp;
-		if (vp != NULL) {
+		if (vp != NULLVP) {
 			nvp->v_flag |= VALIASED;
 			vp->v_flag |= VALIASED;
 			vput(vp);
 		}
 		return (NULLVP);
 	}
-	VOP_UNLOCK(vp);
-	vclean(vp, 0);
+	simple_unlock(&spechash_slock);
+	VOP_UNLOCK(vp, 0, p);
+	simple_lock(&vp->v_interlock);
+	vclean(vp, 0, p);
 	vp->v_op = nvp->v_op;
 	vp->v_tag = nvp->v_tag;
 	nvp->v_type = VNON;
@@ -736,91 +1007,260 @@ loop:
  * been changed to a new file system type).
  */
 int
-vget(vp, lockflag)
-	register struct vnode *vp;
-	int lockflag;
+vget(vp, flags, p)
+        struct vnode *vp;
+	int flags;
+	struct proc *p;
 {
-
+	int error;
 	/*
 	 * If the vnode is in the process of being cleaned out for
 	 * another use, we wait for the cleaning to finish and then
-	 * return failure. Cleaning is determined either by checking
-	 * that the VXLOCK flag is set, or that the use count is
-	 * zero with the back pointer set to show that it has been
-	 * removed from the free list by getnewvnode. The VXLOCK
-	 * flag may not have been set yet because vclean is blocked in
-	 * the VOP_LOCK call waiting for the VOP_INACTIVE to complete.
+	 * return failure. Cleaning is determined by checking that
+	 * the VXLOCK flag is set.
 	 */
-	if ((vp->v_flag & VXLOCK) ||
-	    (vp->v_usecount == 0 &&
-	     vp->v_freelist.tqe_prev == (struct vnode **)0xdeadb)) {
-		vp->v_flag |= VXWANT;
+	if ((flags & LK_INTERLOCK) == 0)
+		simple_lock(&vp->v_interlock);
+	if (vp->v_flag & VXLOCK) {
+ 		vp->v_flag |= VXWANT;
+		simple_unlock(&vp->v_interlock);
 		tsleep((caddr_t)vp, PINOD, "vget", 0);
-		return (1);
+		return (ENOENT);
+ 	}
+	if (vp->v_usecount == 0) {
+		simple_lock(&vnode_free_list_slock);
+		if (vp->v_holdcnt > 0)
+			TAILQ_REMOVE(&vnode_hold_list, vp, v_freelist);
+		else
+			TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
+		simple_unlock(&vnode_free_list_slock);
 	}
-	if (vp->v_usecount == 0)
-		TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
-	vp->v_usecount++;
-	if (lockflag)
-		VOP_LOCK(vp);
+ 	vp->v_usecount++;
+	if (flags & LK_TYPE_MASK) {
+		if ((error = vn_lock(vp, flags | LK_INTERLOCK, p)) != 0) {
+			vunref(vp);
+			simple_unlock(&vp->v_interlock);
+		}
+		return (error);
+	}
+	simple_unlock(&vp->v_interlock);
 	return (0);
 }
 
 /*
- * Vnode reference, just increment the count
+ * Stubs to use when there is no locking to be done on the underlying object.
+ * A minimal shared lock is necessary to ensure that the underlying object
+ * is not revoked while an operation is in progress. So, an active shared
+ * count is maintained in an auxillary vnode lock structure.
+ */
+int
+vop_nolock(v)
+	void *v;
+{
+	struct vop_lock_args /* {
+		struct vnode *a_vp;
+		int a_flags;
+		struct proc *a_p;
+	} */ *ap = v;
+
+#ifdef notyet
+	/*
+	 * This code cannot be used until all the non-locking filesystems
+	 * (notably NFS) are converted to properly lock and release nodes.
+	 * Also, certain vnode operations change the locking state within
+	 * the operation (create, mknod, remove, link, rename, mkdir, rmdir,
+	 * and symlink). Ideally these operations should not change the
+	 * lock state, but should be changed to let the caller of the
+	 * function unlock them. Otherwise all intermediate vnode layers
+	 * (such as union, umapfs, etc) must catch these functions to do
+	 * the necessary locking at their layer. Note that the inactive
+	 * and lookup operations also change their lock state, but this 
+	 * cannot be avoided, so these two operations will always need
+	 * to be handled in intermediate layers.
+	 */
+	struct vnode *vp = ap->a_vp;
+	int vnflags, flags = ap->a_flags;
+
+	if (vp->v_vnlock == NULL) {
+		if ((flags & LK_TYPE_MASK) == LK_DRAIN)
+			return (0);
+		MALLOC(vp->v_vnlock, struct lock *, sizeof(struct lock),
+		    M_VNODE, M_WAITOK);
+		lockinit(vp->v_vnlock, PVFS, "vnlock", 0, 0);
+	}
+	switch (flags & LK_TYPE_MASK) {
+	case LK_DRAIN:
+		vnflags = LK_DRAIN;
+		break;
+	case LK_EXCLUSIVE:
+	case LK_SHARED:
+		vnflags = LK_SHARED;
+		break;
+	case LK_UPGRADE:
+	case LK_EXCLUPGRADE:
+	case LK_DOWNGRADE:
+		return (0);
+	case LK_RELEASE:
+	default:
+		panic("vop_nolock: bad operation %d", flags & LK_TYPE_MASK);
+	}
+	if (flags & LK_INTERLOCK)
+		vnflags |= LK_INTERLOCK;
+	return(lockmgr(vp->v_vnlock, vnflags, &vp->v_interlock, ap->a_p));
+#else /* for now */
+	/*
+	 * Since we are not using the lock manager, we must clear
+	 * the interlock here.
+	 */
+	if (ap->a_flags & LK_INTERLOCK)
+		simple_unlock(&ap->a_vp->v_interlock);
+ 	return (0);
+#endif
+}
+ 
+/*
+ * Decrement the active use count.
+ */
+
+int
+vop_nounlock(v)
+	void *v;
+{
+	struct vop_unlock_args /* {
+		struct vnode *a_vp;
+		int a_flags;
+		struct proc *a_p;
+	} */ *ap = v;
+
+	struct vnode *vp = ap->a_vp;
+
+	if (vp->v_vnlock == NULL)
+		return (0);
+	return (lockmgr(vp->v_vnlock, LK_RELEASE, NULL, ap->a_p));
+}
+
+/*
+ * Return whether or not the node is in use.
+ */
+int
+vop_noislocked(v)
+	void *v;
+{
+	struct vop_islocked_args /* {
+		struct vnode *a_vp;
+	} */ *ap = v;
+
+	struct vnode *vp = ap->a_vp;
+
+	if (vp->v_vnlock == NULL)
+		return (0);
+	return (lockstatus(vp->v_vnlock));
+}
+
+/*
+ * Vnode reference.
  */
 void
 vref(vp)
 	struct vnode *vp;
 {
-
+	simple_lock(&vp->v_interlock);
 	if (vp->v_usecount <= 0)
 		panic("vref used where vget required");
 	vp->v_usecount++;
+	simple_unlock(&vp->v_interlock);
 }
 
-/*
- * vput(), just unlock and vrele()
- */
-void
-vput(vp)
-	register struct vnode *vp;
+
+int
+vunref(vp)
+	struct vnode *vp;
 {
+#ifdef DIAGNOSTIC
+	if (vp == NULL)
+		panic("vrele: null vp");
+#endif
+	simple_lock (&vp->v_interlock);
+	vp->v_usecount--;
+	if (vp->v_usecount > 0) {
+		simple_unlock(&vp->v_interlock);
+		return (vp->v_usecount);
+	}
+#ifdef DIAGNOSTIC
+	if (vp->v_usecount < 0 || vp->v_writecount != 0) {
+		vprint("vrele: bad ref count", vp);
+		panic("vrele: ref cnt");
+	}
+#endif
+	/*
+	 * insert at tail of LRU list
+	 */
+	simple_lock(&vnode_free_list_slock);
+	if (vp->v_holdcnt > 0)
+		TAILQ_INSERT_TAIL(&vnode_hold_list, vp, v_freelist);
+	else
+		TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
+	simple_unlock(&vnode_free_list_slock);
 
-	VOP_UNLOCK(vp);
-	vrele(vp);
+	return (0);
 }
 
 /*
- * Vnode release.
- * If count drops to zero, call inactive routine and return to freelist.
+ * vput(), just unlock and vrele()
  */
 void
-vrele(vp)
+vput(vp)
 	register struct vnode *vp;
 {
+	struct proc *p = curproc;	/* XXX */
 
-#ifdef DIAGNOSTIC
+#ifdef DIGANOSTIC
 	if (vp == NULL)
-		panic("vrele: null vp");
+		panic("vput: null vp");
 #endif
+	simple_lock(&vp->v_interlock);
 	vp->v_usecount--;
-	if (vp->v_usecount > 0)
+	if (vp->v_usecount > 0) {
+		simple_unlock(&vp->v_interlock);
+		VOP_UNLOCK(vp, 0, p);
 		return;
+	}
 #ifdef DIAGNOSTIC
-	if (vp->v_usecount != 0 || vp->v_writecount != 0) {
-		vprint("vrele: bad ref count", vp);
-		panic("vrele: ref cnt");
+	if (vp->v_usecount < 0 || vp->v_writecount != 0) {
+		vprint("vput: bad ref count", vp);
+		panic("vput: ref cnt");
 	}
 #endif
 	/*
 	 * insert at tail of LRU list
 	 */
-	TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
-	VOP_INACTIVE(vp);
+	simple_lock(&vnode_free_list_slock);
+	if (vp->v_holdcnt > 0)
+		TAILQ_INSERT_TAIL(&vnode_hold_list, vp, v_freelist);
+	else
+		TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
+	simple_unlock(&vnode_free_list_slock);
+	simple_unlock(&vp->v_interlock);
+	VOP_INACTIVE(vp, p);
 }
 
 /*
+ * Vnode release - use for active VNODES.
+ * If count drops to zero, call inactive routine and return to freelist.
+ */
+void
+vrele(vp)
+	register struct vnode *vp;
+{
+	struct proc *p = curproc;
+
+	if (vunref(vp) == 0 &&
+	    vn_lock(vp, LK_EXCLUSIVE |LK_INTERLOCK, p) == 0)
+		VOP_INACTIVE(vp, p);
+}
+
+#ifdef DIAGNOSTIC
+/*
  * Page or buffer structure gets a reference.
  */
 void
@@ -828,7 +1268,27 @@ vhold(vp)
 	register struct vnode *vp;
 {
 
+	/*
+	 * If it is on the freelist and the hold count is currently
+	 * zero, move it to the hold list.
+	 *
+	 * The VGONEHACK flag reflects a call from getnewvnode,
+	 * which will remove the vnode from the free list, but
+	 * will not increment the ref count until after it calls vgone
+	 * If the ref count we're incremented first, vgone would
+	 * (incorrectly) try to close the previous instance of the
+	 * underlying object.
+	 */
+  	simple_lock(&vp->v_interlock);
+	if (!(vp->v_flag & VGONEHACK) &&
+	    vp->v_holdcnt == 0 && vp->v_usecount == 0) {
+		simple_lock(&vnode_free_list_slock);
+		TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
+		TAILQ_INSERT_TAIL(&vnode_hold_list, vp, v_freelist);
+		simple_unlock(&vnode_free_list_slock);
+	}
 	vp->v_holdcnt++;
+	simple_unlock(&vp->v_interlock);
 }
 
 /*
@@ -839,10 +1299,26 @@ holdrele(vp)
 	register struct vnode *vp;
 {
 
+	simple_lock(&vp->v_interlock);
 	if (vp->v_holdcnt <= 0)
 		panic("holdrele: holdcnt");
 	vp->v_holdcnt--;
+	/*
+	 * If it is on the holdlist and the hold count drops to
+	 * zero, move it to the free list. 
+	 *
+	 * See above for VGONEHACK
+	 */
+	if (!(vp->v_flag & VGONEHACK) &&
+	    vp->v_holdcnt == 0 && vp->v_usecount == 0) {
+		simple_lock(&vnode_free_list_slock);
+		TAILQ_REMOVE(&vnode_hold_list, vp, v_freelist);
+		TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
+		simple_unlock(&vnode_free_list_slock);
+	}
+	simple_unlock(&vp->v_interlock);
 }
+#endif /* DIAGNOSTIC */
 
 /*
  * Remove any vnodes in the vnode table belonging to mount point mp.
@@ -863,11 +1339,11 @@ vflush(mp, skipvp, flags)
 	struct vnode *skipvp;
 	int flags;
 {
+	struct proc *p = curproc;
 	register struct vnode *vp, *nvp;
 	int busy = 0;
 
-	if ((mp->mnt_flag & MNT_MPBUSY) == 0)
-		panic("vflush: not busy");
+	simple_lock(&mntvnode_slock);
 loop:
 	for (vp = mp->mnt_vnodelist.lh_first; vp; vp = nvp) {
 		if (vp->v_mount != mp)
@@ -878,24 +1354,32 @@ loop:
 		 */
 		if (vp == skipvp)
 			continue;
+		
+		simple_lock(&vp->v_interlock);
 		/*
 		 * Skip over a vnodes marked VSYSTEM.
 		 */
-		if ((flags & SKIPSYSTEM) && (vp->v_flag & VSYSTEM))
+		if ((flags & SKIPSYSTEM) && (vp->v_flag & VSYSTEM)) {
+			simple_unlock(&vp->v_interlock);
 			continue;
+		}
 		/*
 		 * If WRITECLOSE is set, only flush out regular file
 		 * vnodes open for writing.
 		 */
 		if ((flags & WRITECLOSE) &&
-		    (vp->v_writecount == 0 || vp->v_type != VREG))
+		    (vp->v_writecount == 0 || vp->v_type != VREG)) {
+			simple_unlock(&vp->v_interlock);
 			continue;
+		}
 		/*
 		 * With v_usecount == 0, all we need to do is clear
 		 * out the vnode data structures and we are done.
 		 */
 		if (vp->v_usecount == 0) {
-			vgone(vp);
+			simple_unlock(&mntvnode_slock);
+			vgonel(vp, p);
+			simple_lock(&mntvnode_slock);
 			continue;
 		}
 		/*
@@ -904,21 +1388,25 @@ loop:
 		 * anonymous device. For all other files, just kill them.
 		 */
 		if (flags & FORCECLOSE) {
+			simple_unlock(&mntvnode_slock);
 			if (vp->v_type != VBLK && vp->v_type != VCHR) {
-				vgone(vp);
+				vgonel(vp, p);
 			} else {
-				vclean(vp, 0);
+				vclean(vp, 0, p);
 				vp->v_op = spec_vnodeop_p;
 				insmntque(vp, (struct mount *)0);
 			}
+			simple_lock(&mntvnode_slock);
 			continue;
 		}
 #ifdef DEBUG
 		if (busyprt)
 			vprint("vflush: busy vnode", vp);
 #endif
+		simple_unlock(&vp->v_interlock);
 		busy++;
 	}
+	simple_unlock(&mntvnode_slock);
 	if (busy)
 		return (EBUSY);
 	return (0);
@@ -926,11 +1414,13 @@ loop:
 
 /*
  * Disassociate the underlying file system from a vnode.
+ * The vnode interlock is held on entry.
  */
 void
-vclean(vp, flags)
+vclean(vp, flags, p)
 	register struct vnode *vp;
 	int flags;
+	struct proc *p;
 {
 	int active;
 
@@ -941,15 +1431,8 @@ vclean(vp, flags)
 	 * race against ourselves to recycle it.
 	 */
 	if ((active = vp->v_usecount) != 0)
-		VREF(vp);
-	/*
-	 * Even if the count is zero, the VOP_INACTIVE routine may still
-	 * have the object locked while it cleans it out. The VOP_LOCK
-	 * ensures that the VOP_INACTIVE routine is done with its work.
-	 * For active vnodes, it ensures that no other activity can
-	 * occur while the underlying object is being cleaned out.
-	 */
-	VOP_LOCK(vp);
+		vp->v_usecount++;
+
 	/*
 	 * Prevent the vnode from being recycled or
 	 * brought into use while we clean it out.
@@ -957,32 +1440,57 @@ vclean(vp, flags)
 	if (vp->v_flag & VXLOCK)
 		panic("vclean: deadlock");
 	vp->v_flag |= VXLOCK;
+
+	
 	/*
-	 * Clean out any buffers associated with the vnode.
+	 * Even if the count is zero, the VOP_INACTIVE routine may still
+	 * have the object locked while it cleans it out. The VOP_LOCK
+	 * ensures that the VOP_INACTIVE routine is done with its work.
+	 * For active vnodes, it ensures that no other activity can
+	 * occur while the underlying object is being cleaned out.
 	 */
-	if (flags & DOCLOSE)
-		vinvalbuf(vp, V_SAVE, NOCRED, NULL, 0, 0);
+	VOP_LOCK(vp, LK_DRAIN | LK_INTERLOCK, p);
+
 	/*
-	 * Any other processes trying to obtain this lock must first
-	 * wait for VXLOCK to clear, then call the new lock operation.
+	 * Clean out any buffers associated with the vnode.
 	 */
-	VOP_UNLOCK(vp);
+	if (flags & DOCLOSE)
+		vinvalbuf(vp, V_SAVE, NOCRED, p, 0, 0);
 	/*
 	 * If purging an active vnode, it must be closed and
-	 * deactivated before being reclaimed.
+	 * deactivated before being reclaimed. Note that the
+	 * VOP_INACTIVE will unlock the vnode
 	 */
 	if (active) {
 		if (flags & DOCLOSE)
-			VOP_CLOSE(vp, FNONBLOCK, NOCRED, NULL);
-		VOP_INACTIVE(vp);
+			VOP_CLOSE(vp, FNONBLOCK, NOCRED, p);
+		VOP_INACTIVE(vp, p);
+	} else {
+		/*
+		 * Any other processes trying to obtain this lock must first
+		 * wait for VXLOCK to clear, then call the new lock operation.
+		 */
+		VOP_UNLOCK(vp, 0, p);
 	}
+
 	/*
 	 * Reclaim the vnode.
 	 */
-	if (VOP_RECLAIM(vp))
+	if (VOP_RECLAIM(vp, p))
 		panic("vclean: cannot reclaim");
-	if (active)
-		vrele(vp);
+	if (active) {
+		if (vunref(vp) == 0 &&
+		    vp->v_holdcnt > 0)
+			panic("vclean: not clean");
+		simple_unlock(&vp->v_interlock);
+	}
+	cache_purge(vp);
+	if (vp->v_vnlock) {
+		if ((vp->v_vnlock->lk_flags & LK_DRAINED) == 0)
+			vprint("vclean: lock not drained", vp);
+		FREE(vp->v_vnlock, M_VNODE);
+		vp->v_vnlock = NULL;
+	}
 
 	/*
 	 * Done with purge, notify sleepers of the grim news.
@@ -1000,12 +1508,25 @@ vclean(vp, flags)
  * Eliminate all activity associated with  the requested vnode
  * and with all vnodes aliased to the requested vnode.
  */
-void
-vgoneall(vp)
-	register struct vnode *vp;
+int
+vop_revoke(v)
+	void *v;
 {
-	register struct vnode *vq;
+	struct vop_revoke_args /* {
+	        struct vnode *a_vp;
+		int a_flags;
+	} */ *ap = v;
+	struct vnode *vp, *vq;
+	struct proc *p = curproc;
+
+#ifdef DIAGNOSTIC
+	if ((ap->a_flags & REVOKEALL) == 0)
+		panic("vop_revoke");
+#endif
 
+	vp = ap->a_vp;
+	simple_lock(&vp->v_interlock);
+ 
 	if (vp->v_flag & VALIASED) {
 		/*
 		 * If a vgone (or vclean) is already in progress,
@@ -1013,19 +1534,23 @@ vgoneall(vp)
 		 */
 		if (vp->v_flag & VXLOCK) {
 			vp->v_flag |= VXWANT;
-			tsleep((caddr_t)vp, PINOD, "vgoneall", 0);
-			return;
+			simple_unlock(&vp->v_interlock);
+			tsleep((caddr_t)vp, PINOD, "vop_revokeall", 0);
+			return(0);
 		}
 		/*
 		 * Ensure that vp will not be vgone'd while we
 		 * are eliminating its aliases.
 		 */
 		vp->v_flag |= VXLOCK;
+		simple_unlock(&vp->v_interlock);
 		while (vp->v_flag & VALIASED) {
+			simple_lock(&spechash_slock);
 			for (vq = *vp->v_hashchain; vq; vq = vq->v_specnext) {
 				if (vq->v_rdev != vp->v_rdev ||
 				    vq->v_type != vp->v_type || vp == vq)
 					continue;
+				simple_unlock(&spechash_slock);
 				vgone(vq);
 				break;
 			}
@@ -1035,9 +1560,34 @@ vgoneall(vp)
 		 * really eliminate the vnode after which time
 		 * vgone will awaken any sleepers.
 		 */
+		simple_lock(&vp->v_interlock);
 		vp->v_flag &= ~VXLOCK;
 	}
-	vgone(vp);
+	vgonel(vp, p);
+	return (0);
+}
+
+
+/*
+ * Recycle an unused vnode to the front of the free list.
+ * Release the passed interlock if the vnode will be recycled.
+ */
+int
+vrecycle(vp, inter_lkp, p)
+	struct vnode *vp;
+	struct simplelock *inter_lkp;
+	struct proc *p;
+{
+
+	simple_lock(&vp->v_interlock);
+	if (vp->v_usecount == 0) {
+		if (inter_lkp)
+			simple_unlock(inter_lkp);
+		vgonel(vp, p);
+		return (1);
+	}
+	simple_unlock(&vp->v_interlock);
+	return (0);
 }
 
 /*
@@ -1048,6 +1598,20 @@ void
 vgone(vp)
 	register struct vnode *vp;
 {
+	struct proc *p = curproc;
+
+	simple_lock (&vp->v_interlock);
+	vgonel(vp, p);
+}
+
+/*
+ * vgone, with the vp interlock held.
+ */
+void
+vgonel(vp, p)
+	struct vnode *vp;
+	struct proc *p;
+{
 	register struct vnode *vq;
 	struct vnode *vx;
 
@@ -1057,21 +1621,25 @@ vgone(vp)
 	 */
 	if (vp->v_flag & VXLOCK) {
 		vp->v_flag |= VXWANT;
+		simple_unlock(&vp->v_interlock);
 		tsleep((caddr_t)vp, PINOD, "vgone", 0);
 		return;
 	}
 	/*
 	 * Clean out the filesystem specific data.
 	 */
-	vclean(vp, DOCLOSE);
+	vclean(vp, DOCLOSE, p);
 	/*
 	 * Delete from old mount point vnode list, if on one.
 	 */
-	insmntque(vp, (struct mount *)0);
+	if (vp->v_mount != NULL)
+		insmntque(vp, (struct mount *)0);
 	/*
-	 * If special device, remove it from special device alias list.
+	 * If special device, remove it from special device alias list 
+	 * if it is on one.
 	 */
-	if (vp->v_type == VBLK || vp->v_type == VCHR) {
+	if ((vp->v_type == VBLK || vp->v_type == VCHR) && vp->v_specinfo != 0) {
+		simple_lock(&spechash_slock);
 		if (*vp->v_hashchain == vp) {
 			*vp->v_hashchain = vp->v_specnext;
 		} else {
@@ -1100,27 +1668,26 @@ vgone(vp)
 				vx->v_flag &= ~VALIASED;
 			vp->v_flag &= ~VALIASED;
 		}
+		simple_unlock(&spechash_slock);
 		FREE(vp->v_specinfo, M_VNODE);
 		vp->v_specinfo = NULL;
 	}
 	/*
 	 * If it is on the freelist and not already at the head,
-	 * move it to the head of the list. The test of the back
-	 * pointer and the reference count of zero is because
-	 * it will be removed from the free list by getnewvnode,
-	 * but will not have its reference count incremented until
-	 * after calling vgone. If the reference count were
-	 * incremented first, vgone would (incorrectly) try to
-	 * close the previous instance of the underlying object.
-	 * So, the back pointer is explicitly set to `0xdeadb' in
-	 * getnewvnode after removing it from the freelist to ensure
-	 * that we do not try to move it here.
+	 * move it to the head of the list. 
+	 *
+	 * See above about the VGONEHACK
 	 */
-	if (vp->v_usecount == 0 &&
-	    vp->v_freelist.tqe_prev != (struct vnode **)0xdeadb &&
-	    vnode_free_list.tqh_first != vp) {
-		TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
-		TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
+	if (vp->v_usecount == 0) {
+		simple_lock(&vnode_free_list_slock);
+		if (vp->v_holdcnt > 0)
+			panic("vgonel: not clean");		
+		if (!(vp->v_flag & VGONEHACK) &&
+		    TAILQ_FIRST(&vnode_free_list) != vp) {
+			TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
+			TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
+		}
+		simple_unlock(&vnode_free_list_slock);
 	}
 	vp->v_type = VBAD;
 }
@@ -1135,14 +1702,18 @@ vfinddev(dev, type, vpp)
 	struct vnode **vpp;
 {
 	register struct vnode *vp;
+	int rc =0;
 
+	simple_lock(&spechash_slock);
 	for (vp = speclisth[SPECHASH(dev)]; vp; vp = vp->v_specnext) {
 		if (dev != vp->v_rdev || type != vp->v_type)
 			continue;
 		*vpp = vp;
-		return (1);
+		rc = 1;
+		break;
 	}
-	return (0);
+	simple_unlock(&spechash_slock);
+	return (rc);
 }
 
 /*
@@ -1150,14 +1721,15 @@ vfinddev(dev, type, vpp)
  */
 int
 vcount(vp)
-	register struct vnode *vp;
+	struct vnode *vp;
 {
-	register struct vnode *vq, *vnext;
+	struct vnode *vq, *vnext;
 	int count;
 
 loop:
 	if ((vp->v_flag & VALIASED) == 0)
 		return (vp->v_usecount);
+	simple_lock(&spechash_slock);
 	for (count = 0, vq = *vp->v_hashchain; vq; vq = vnext) {
 		vnext = vq->v_specnext;
 		if (vq->v_rdev != vp->v_rdev || vq->v_type != vp->v_type)
@@ -1166,11 +1738,13 @@ loop:
 		 * Alias, but not in use, so flush it out.
 		 */
 		if (vq->v_usecount == 0 && vq != vp) {
+			simple_unlock(&spechash_slock);
 			vgone(vq);
 			goto loop;
 		}
 		count += vq->v_usecount;
 	}
+	simple_unlock(&spechash_slock);
 	return (count);
 }
 
@@ -1225,21 +1799,77 @@ vprint(label, vp)
 void
 printlockedvnodes()
 {
-	register struct mount *mp;
+	struct proc *p = curproc;
+	register struct mount *mp, *nmp;
 	register struct vnode *vp;
 
 	printf("Locked vnodes\n");
+	simple_lock(&mountlist_slock);
 	for (mp = mountlist.cqh_first; mp != (void *)&mountlist;
-	     mp = mp->mnt_list.cqe_next) {
+	     mp = nmp) {
+		if (vfs_busy(mp, LK_NOWAIT, &mountlist_slock, p)) { 
+			nmp = mp->mnt_list.cque_next;
+			continue;
+		}
 		for (vp = mp->mnt_vnodelist.lh_first;
 		     vp != NULL;
-		     vp = vp->v_mntvnodes.le_next)
+		     vp = vp->v_mntvnodes.le_next) {
 			if (VOP_ISLOCKED(vp))
 				vprint((char *)0, vp);
-	}
+		simple_lock(&mountlist_slock);
+		nmp = mp->mnt_list.cqe_next;
+		vfs_unbusy(mp, p);
+ 	}
+	simple_unlock(&mountlist_slock);
+
 }
 #endif
 
+/*
+ * Top level filesystem related information gathering.
+ */
+int
+vfs_sysctl(name, namelen, oldp, oldlenp, newp, newlen, p)
+	int *name;
+	u_int namelen;
+	void *oldp;
+	size_t *oldlenp;
+	void *newp;
+	size_t newlen;
+	struct proc *p;
+{
+	struct vfsconf *vfsp;
+
+	/* all sysctl names at this level are at least name and field */
+	if (namelen < 2)
+		return (ENOTDIR);		/* overloaded */
+	if (name[0] != VFS_GENERIC) {
+		for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
+			if (vfsp->vfc_typenum == name[0])
+				break;
+		if (vfsp == NULL)
+			return (EOPNOTSUPP);
+		return ((*vfsp->vfc_vfsops->vfs_sysctl)(&name[1], namelen - 1,
+		    oldp, oldlenp, newp, newlen, p));
+	}
+	switch (name[1]) {
+	case VFS_MAXTYPENUM:
+		return (sysctl_rdint(oldp, oldlenp, newp, maxvfsconf));
+	case VFS_CONF:
+		if (namelen < 3)
+			return (ENOTDIR);	/* overloaded */
+		for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
+			if (vfsp->vfc_typenum == name[2])
+				break;
+		if (vfsp == NULL)
+			return (EOPNOTSUPP);
+		return (sysctl_rdstruct(oldp, oldlenp, newp, vfsp,
+		    sizeof(struct vfsconf)));
+	}
+	return (EOPNOTSUPP);
+}
+
+
 int kinfo_vdebug = 1;
 int kinfo_vgetfailed;
 #define KINFO_VNODESLOP	10
@@ -1249,12 +1879,13 @@ int kinfo_vgetfailed;
  */
 /* ARGSUSED */
 int
-sysctl_vnode(where, sizep)
+sysctl_vnode(where, sizep, p)
 	char *where;
 	size_t *sizep;
+	struct proc *p;
 {
 	register struct mount *mp, *nmp;
-	struct vnode *vp;
+	struct vnode *vp, *nvp;
 	register char *bp = where, *savebp;
 	char *ewhere;
 	int error;
@@ -1267,27 +1898,32 @@ sysctl_vnode(where, sizep)
 	}
 	ewhere = where + *sizep;
 		
+	simple_lock(&mountlist_slock);
 	for (mp = mountlist.cqh_first; mp != (void *)&mountlist; mp = nmp) {
-		nmp = mp->mnt_list.cqe_next;
-		if (vfs_busy(mp))
+		if (vfs_busy(mp, LK_NOWAIT, &mountlist_slock, p)) {
+			nmp = mp->mnt_list.cqe_next;
 			continue;
+		}
 		savebp = bp;
 again:
 		for (vp = mp->mnt_vnodelist.lh_first;
 		     vp != NULL;
-		     vp = vp->v_mntvnodes.le_next) {
+		     vp = nvp) {
 			/*
 			 * Check that the vp is still associated with
 			 * this filesystem.  RACE: could have been
 			 * recycled onto the same filesystem.
 			 */
 			if (vp->v_mount != mp) {
+				simple_unlock(&mntvnode_slock);
 				if (kinfo_vdebug)
 					printf("kinfo: vp changed\n");
 				bp = savebp;
 				goto again;
 			}
+			nvp = vp->v_mntvnodes.le_next;
 			if (bp + VPTRSZ + VNODESZ > ewhere) {
+				simple_unlock(&mntvnode_slock);
 				*sizep = bp - where;
 				return (ENOMEM);
 			}
@@ -1295,10 +1931,17 @@ again:
 			   (error = copyout((caddr_t)vp, bp + VPTRSZ, VNODESZ)))
 				return (error);
 			bp += VPTRSZ + VNODESZ;
+			simple_lock(&mntvnode_slock);
 		}
-		vfs_unbusy(mp);
+
+		simple_unlock(&mntvnode_slock);
+		simple_lock(&mountlist_slock);
+		nmp = mp->mnt_list.cqe_next;
+		vfs_unbusy(mp, p);
 	}
 
+	simple_unlock(&mountlist_slock);
+
 	*sizep = bp - where;
 	return (0);
 }
@@ -1311,26 +1954,31 @@ vfs_mountedon(vp)
 	register struct vnode *vp;
 {
 	register struct vnode *vq;
+	int error = 0;
 
-	if (vp->v_specflags & SI_MOUNTEDON)
+ 	if (vp->v_specmountpoint != NULL)
 		return (EBUSY);
 	if (vp->v_flag & VALIASED) {
+		simple_lock(&spechash_slock);
 		for (vq = *vp->v_hashchain; vq; vq = vq->v_specnext) {
 			if (vq->v_rdev != vp->v_rdev ||
 			    vq->v_type != vp->v_type)
 				continue;
-			if (vq->v_specflags & SI_MOUNTEDON)
-				return (EBUSY);
-		}
+			if (vq->v_specmountpoint != NULL) {
+				error = EBUSY;
+				break;
+			}
+ 		}
+		simple_unlock(&spechash_slock);
 	}
-	return (0);
+	return (error);
 }
 
 /*
  * Build hash lists of net addresses and hang them off the mount point.
  * Called by ufs_mount() to set up the lists of export addresses.
  */
-static int
+int
 vfs_hang_addrlist(mp, nep, argp)
 	struct mount *mp;
 	struct netexport *nep;
@@ -1404,7 +2052,7 @@ out:
 }
 
 /* ARGSUSED */
-static int
+int
 vfs_free_netcred(rn, w)
 	struct radix_node *rn;
 	void *w;
@@ -1419,7 +2067,7 @@ vfs_free_netcred(rn, w)
 /*
  * Free the net address hash lists that are hanging off the mount points.
  */
-static void
+void
 vfs_free_addrlist(nep)
 	struct netexport *nep;
 {
@@ -1666,3 +2314,161 @@ fs_sysctl(name, namelen, oldp, oldlenp, newp, newlen, p)
 	}
 	return (*fn)(name + 1, namelen - 1, oldp, oldlenp, newp, newlen, p);
 }
+
+/*
+ * Routine to create and manage a filesystem syncer vnode.
+ */
+#define sync_close nullop
+int   sync_fsync __P((void *));
+int   sync_inactive __P((void *));
+#define sync_reclaim nullop
+#define sync_lock vop_nolock
+#define sync_unlock vop_nounlock
+int   sync_print __P((void *));
+#define sync_islocked vop_noislocked
+ 
+int (**sync_vnodeop_p) __P((void *));
+struct vnodeopv_entry_desc sync_vnodeop_entries[] = {
+      { &vop_default_desc, vn_default_error },
+      { &vop_close_desc, sync_close },                /* close */
+      { &vop_fsync_desc, sync_fsync },                /* fsync */
+      { &vop_inactive_desc, sync_inactive },          /* inactive */
+      { &vop_reclaim_desc, sync_reclaim },            /* reclaim */
+      { &vop_lock_desc, sync_lock },                  /* lock */
+      { &vop_unlock_desc, sync_unlock },              /* unlock */
+      { &vop_print_desc, sync_print },                /* print */
+      { &vop_islocked_desc, sync_islocked },          /* islocked */
+      { (struct vnodeop_desc*)NULL, (int(*) __P((void *)))NULL }
+};
+struct vnodeopv_desc sync_vnodeop_opv_desc =
+      { &sync_vnodeop_p, sync_vnodeop_entries };
+
+/*
+ * Create a new filesystem syncer vnode for the specified mount point.
+ */
+int
+vfs_allocate_syncvnode(mp)
+      struct mount *mp;
+{
+      struct vnode *vp;
+      static long start, incr, next;
+      int error;
+
+      /* Allocate a new vnode */
+      if ((error = getnewvnode(VT_VFS, mp, sync_vnodeop_p, &vp)) != 0) {
+              mp->mnt_syncer = NULL;
+              return (error);
+      }
+      vp->v_writecount = 1;
+      vp->v_type = VNON;
+      /*
+       * Place the vnode onto the syncer worklist. We attempt to
+       * scatter them about on the list so that they will go off
+       * at evenly distributed times even if all the filesystems
+       * are mounted at once.
+       */
+      next += incr;
+      if (next == 0 || next > syncer_maxdelay) {
+              start /= 2;
+              incr /= 2;
+              if (start == 0) {
+                      start = syncer_maxdelay / 2;
+                      incr = syncer_maxdelay;
+              }
+              next = start;
+      }
+      vn_syncer_add_to_worklist(vp, next);
+      mp->mnt_syncer = vp;
+      return (0);
+}
+
+/*
+ * Do a lazy sync of the filesystem.
+ */
+int
+sync_fsync(v)
+	void *v;
+{
+      struct vop_fsync_args /* {
+              struct vnode *a_vp;
+              struct ucred *a_cred;
+              int a_waitfor;
+              struct proc *a_p;
+      } */ *ap = v;
+
+      struct vnode *syncvp = ap->a_vp;
+      struct mount *mp = syncvp->v_mount;
+      int asyncflag;
+
+      /*
+       * We only need to do something if this is a lazy evaluation.
+       */
+      if (ap->a_waitfor != MNT_LAZY)
+              return (0);
+
+      /*
+       * Move ourselves to the back of the sync list.
+       */
+      LIST_REMOVE(syncvp, v_synclist);
+      vn_syncer_add_to_worklist(syncvp, syncdelay);
+
+      /*
+       * Walk the list of vnodes pushing all that are dirty and
+       * not already on the sync list.
+       */
+      simple_lock(&mountlist_slock);
+      if (vfs_busy(mp, LK_NOWAIT, &mountlist_slock, ap->a_p) == 0) {
+              asyncflag = mp->mnt_flag & MNT_ASYNC;
+              mp->mnt_flag &= ~MNT_ASYNC;
+              VFS_SYNC(mp, MNT_LAZY, ap->a_cred, ap->a_p);
+              if (asyncflag)
+                      mp->mnt_flag |= MNT_ASYNC;
+              vfs_unbusy(mp, ap->a_p);
+      }
+      return (0);
+}
+
+/*
+ * The syncer vnode is no longer needed and is being decommissioned.
+ */
+int
+sync_inactive(v)
+	void *v;
+	
+{
+      struct vop_inactive_args /* {
+               struct vnode *a_vp;
+               struct proc *a_p;
+      } */ *ap = v;
+
+      struct vnode *vp = ap->a_vp;
+
+      if (vp->v_usecount == 0)
+              return (0);
+      vp->v_mount->mnt_syncer = NULL;
+      LIST_REMOVE(vp, v_synclist);
+      vp->v_writecount = 0;
+      vput(vp);
+      return (0);
+}
+
+/*
+ * Print out a syncer vnode.
+ */
+int
+sync_print(v)
+	void *v;
+
+{
+      struct vop_print_args /* {
+              struct vnode *a_vp;
+      } */ *ap = v;
+      struct vnode *vp = ap->a_vp;
+
+      printf("syncer vnode");
+      if (vp->v_vnlock != NULL)
+              lockmgr_printinfo(vp->v_vnlock);
+      printf("\n");
+      return (0);
+}
+