This is the kernel Lite/2 commit. There are some requisite userland

changes, so don't expect to be able to run the kernel as-is (very well)
without the appropriate Lite/2 userland changes.

The system boots and can mount UFS filesystems.

Untested: ext2fs, msdosfs, NFS
Known problems: Incorrect Berkeley ID strings in some files.
		Mount_std mounts will not work until the getfsent
		library routine is changed.

Reviewed by:	various people
Submitted by:	Jeffery Hsu <hsu@freebsd.org>

4 files changed, 236 insertions, 72 deletions

diff --git a/sys/fs/nullfs/null.h b/sys/fs/nullfs/null.h
index beadb42..70a81b2 100644
--- a/sys/fs/nullfs/null.h
+++ b/sys/fs/nullfs/null.h
@@ -33,7 +33,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	@(#)null.h	8.2 (Berkeley) 1/21/94
+ *	@(#)null.h	8.3 (Berkeley) 8/20/94
  *
  * $FreeBSD$
  */
@@ -52,8 +52,7 @@ struct null_mount {
  * A cache of vnode references
  */
 struct null_node {
-	struct null_node	*null_forw;	/* Hash chain */
-	struct null_node	*null_back;
+	LIST_ENTRY(null_node)	null_hash;	/* Hash list */
 	struct vnode	        *null_lowervp;	/* VREFed once */
 	struct vnode		*null_vnode;	/* Back pointer */
 };
diff --git a/sys/fs/nullfs/null_subr.c b/sys/fs/nullfs/null_subr.c
index a14a7e4..4418631 100644
--- a/sys/fs/nullfs/null_subr.c
+++ b/sys/fs/nullfs/null_subr.c
@@ -33,13 +33,14 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	@(#)null_subr.c	8.4 (Berkeley) 1/21/94
+ *	@(#)null_subr.c	8.7 (Berkeley) 5/14/95
  *
  * $FreeBSD$
  */
 
 #include <sys/param.h>
 #include <sys/systm.h>
+#include <sys/proc.h>
 #include <sys/time.h>
 #include <sys/types.h>
 #include <sys/vnode.h>
@@ -48,11 +49,8 @@
 #include <sys/malloc.h>
 #include <miscfs/nullfs/null.h>
 
-extern int	nullfs_init __P((void));
-
 #define LOG2_SIZEVNODE 7		/* log2(sizeof struct vnode) */
 #define	NNULLNODECACHE 16
-#define	NULL_NHASH(vp) ((((u_long)vp)>>LOG2_SIZEVNODE) & (NNULLNODECACHE-1))
 
 /*
  * Null layer cache:
@@ -62,51 +60,32 @@ extern int	nullfs_init __P((void));
  * alias is removed the lower vnode is vrele'd.
  */
 
-/*
- * Cache head
- */
-struct null_node_cache {
-	struct null_node	*ac_forw;
-	struct null_node	*ac_back;
-};
-
-static struct null_node_cache null_node_cache[NNULLNODECACHE];
+#define	NULL_NHASH(vp) \
+	(&null_node_hashtbl[(((u_long)vp)>>LOG2_SIZEVNODE) & null_node_hash])
+LIST_HEAD(null_node_hashhead, null_node) *null_node_hashtbl;
+u_long null_node_hash;
 
 static int	null_node_alloc __P((struct mount *mp, struct vnode *lowervp,
 				     struct vnode **vpp));
 static struct vnode *
 		null_node_find __P((struct mount *mp, struct vnode *lowervp));
-static struct null_node_cache *
-		null_node_hash __P((struct vnode *lowervp));
 
 /*
  * Initialise cache headers
  */
 int
-nullfs_init()
+nullfs_init(vfsp)
+	struct vfsconf *vfsp;
 {
-	struct null_node_cache *ac;
+
 #ifdef NULLFS_DIAGNOSTIC
 	printf("nullfs_init\n");		/* printed during system boot */
 #endif
-
-	for (ac = null_node_cache; ac < null_node_cache + NNULLNODECACHE; ac++)
-		ac->ac_forw = ac->ac_back = (struct null_node *) ac;
+	null_node_hashtbl = hashinit(NNULLNODECACHE, M_CACHE, &null_node_hash);
 	return (0);
 }
 
 /*
- * Compute hash list for given lower vnode
- */
-static struct null_node_cache *
-null_node_hash(lowervp)
-struct vnode *lowervp;
-{
-
-	return (&null_node_cache[NULL_NHASH(lowervp)]);
-}
-
-/*
  * Return a VREF'ed alias for lower vnode if already exists, else 0.
  */
 static struct vnode *
@@ -114,7 +93,8 @@ null_node_find(mp, lowervp)
 	struct mount *mp;
 	struct vnode *lowervp;
 {
-	struct null_node_cache *hd;
+	struct proc *p = curproc;	/* XXX */
+	struct null_node_hashhead *hd;
 	struct null_node *a;
 	struct vnode *vp;
 
@@ -124,9 +104,9 @@ null_node_find(mp, lowervp)
 	 * the lower vnode.  If found, the increment the null_node
 	 * reference count (but NOT the lower vnode's VREF counter).
 	 */
-	hd = null_node_hash(lowervp);
+	hd = NULL_NHASH(lowervp);
 loop:
-	for (a = hd->ac_forw; a != (struct null_node *) hd; a = a->null_forw) {
+	for (a = hd->lh_first; a != 0; a = a->null_hash.le_next) {
 		if (a->null_lowervp == lowervp && NULLTOV(a)->v_mount == mp) {
 			vp = NULLTOV(a);
 			/*
@@ -134,7 +114,7 @@ loop:
 			 * stuff, but we don't want to lock
 			 * the lower node.
 			 */
-			if (vget(vp, 0)) {
+			if (vget(vp, 0, p)) {
 				printf ("null_node_find: vget failed.\n");
 				goto loop;
 			};
@@ -157,7 +137,7 @@ null_node_alloc(mp, lowervp, vpp)
 	struct vnode *lowervp;
 	struct vnode **vpp;
 {
-	struct null_node_cache *hd;
+	struct null_node_hashhead *hd;
 	struct null_node *xp;
 	struct vnode *othervp, *vp;
 	int error;
@@ -194,8 +174,8 @@ null_node_alloc(mp, lowervp, vpp)
 		return 0;
 	};
 	VREF(lowervp);   /* Extra VREF will be vrele'd in null_node_create */
-	hd = null_node_hash(lowervp);
-	insque(xp, hd);
+	hd = NULL_NHASH(lowervp);
+	LIST_INSERT_HEAD(hd, xp, null_hash);
 	return 0;
 }
 
@@ -250,9 +230,8 @@ null_node_create(mp, lowervp, newvpp)
 #ifdef DIAGNOSTIC
 	if (lowervp->v_usecount < 1) {
 		/* Should never happen... */
-		vprint ("null_node_create: alias ",aliasvp);
-		vprint ("null_node_create: lower ",lowervp);
-		printf ("null_node_create: lower has 0 usecount.\n");
+		vprint ("null_node_create: alias ", aliasvp);
+		vprint ("null_node_create: lower ", lowervp);
 		panic ("null_node_create: lower has 0 usecount.");
 	};
 #endif
diff --git a/sys/fs/nullfs/null_vfsops.c b/sys/fs/nullfs/null_vfsops.c
index e2aeeba..339b7c1 100644
--- a/sys/fs/nullfs/null_vfsops.c
+++ b/sys/fs/nullfs/null_vfsops.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1992, 1993
+ * Copyright (c) 1992, 1993, 1995
  *	The Regents of the University of California.  All rights reserved.
  *
  * This code is derived from software donated to Berkeley by
@@ -46,7 +46,7 @@
 
 #include <sys/param.h>
 #include <sys/systm.h>
-#include <sys/kernel.h>
+#include <sys/proc.h>
 #include <sys/time.h>
 #include <sys/types.h>
 #include <sys/vnode.h>
@@ -55,7 +55,7 @@
 #include <sys/malloc.h>
 #include <miscfs/nullfs/null.h>
 
-extern int	nullfs_init __P((void));
+extern int	nullfs_init __P((struct vfsconf *));
 
 static int	nullfs_fhtovp __P((struct mount *mp, struct fid *fidp,
 				   struct mbuf *nam, struct vnode **vpp,
@@ -146,7 +146,7 @@ nullfs_mount(mp, path, data, ndp, p)
 	/*
 	 * Unlock the node (either the lower or the alias)
 	 */
-	VOP_UNLOCK(vp);
+	VOP_UNLOCK(vp, 0, p);
 	/*
 	 * Make sure the node alias worked
 	 */
@@ -166,7 +166,7 @@ nullfs_mount(mp, path, data, ndp, p)
 	if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL)
 		mp->mnt_flag |= MNT_LOCAL;
 	mp->mnt_data = (qaddr_t) xmp;
-	getnewfsid(mp, MOUNT_LOFS);
+	vfs_getnewfsid(mp);
 
 	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
 	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
@@ -212,12 +212,8 @@ nullfs_unmount(mp, mntflags, p)
 	printf("nullfs_unmount(mp = %x)\n", mp);
 #endif
 
-	if (mntflags & MNT_FORCE) {
-		/* lofs can never be rootfs so don't check for it */
-		if (!doforce)
-			return (EINVAL);
+	if (mntflags & MNT_FORCE)
 		flags |= FORCECLOSE;
-	}
 
 	/*
 	 * Clear out buffer cache.  I don't think we
@@ -259,6 +255,7 @@ nullfs_root(mp, vpp)
 	struct mount *mp;
 	struct vnode **vpp;
 {
+	struct proc *p = curproc;	/* XXX */
 	struct vnode *vp;
 
 #ifdef NULLFS_DIAGNOSTIC
@@ -273,7 +270,7 @@ nullfs_root(mp, vpp)
 	 */
 	vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
 	VREF(vp);
-	VOP_LOCK(vp);
+	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
 	*vpp = vp;
 	return 0;
 }
diff --git a/sys/fs/nullfs/null_vnops.c b/sys/fs/nullfs/null_vnops.c
index ec279bc..c1af96f 100644
--- a/sys/fs/nullfs/null_vnops.c
+++ b/sys/fs/nullfs/null_vnops.c
@@ -33,7 +33,13 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	@(#)null_vnops.c	8.1 (Berkeley) 6/10/93
+ *	@(#)null_vnops.c	8.6 (Berkeley) 5/27/95
+ *
+ * Ancestors:
+ *	@(#)lofs_vnops.c	1.2 (Berkeley) 6/18/92
+ *	$Id: null_vnops.c,v 1.11.2000.1 1996/09/17 14:32:31 peter Exp $
+ *	...and...
+ *	@(#)null_vnodeops.c 1.20 92/07/07 UCLA Ficus project
  *
  * $FreeBSD$
  */
@@ -88,13 +94,21 @@
  * in the arguments and, if a vnode is return by the operation,
  * stacks a null-node on top of the returned vnode.
  *
- * Although bypass handles most operations,
- * vop_getattr, _inactive, _reclaim, and _print are not bypassed.
- * Vop_getattr must change the fsid being returned.
+ * Although bypass handles most operations, vop_getattr, vop_lock,
+ * vop_unlock, vop_inactive, vop_reclaim, and vop_print are not
+ * bypassed. Vop_getattr must change the fsid being returned.
+ * Vop_lock and vop_unlock must handle any locking for the
+ * current vnode as well as pass the lock request down.
  * Vop_inactive and vop_reclaim are not bypassed so that
- * they can handle freeing null-layer specific data.
- * Vop_print is not bypassed to avoid excessive debugging
- * information.
+ * they can handle freeing null-layer specific data. Vop_print
+ * is not bypassed to avoid excessive debugging information.
+ * 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.
  *
  *
  * INSTANTIATING VNODE STACKS
@@ -178,7 +192,7 @@ static int null_bug_bypass = 0;   /* for debugging: enables bypass printf'ing */
 SYSCTL_INT(_debug, OID_AUTO, nullfs_bug_bypass, CTLFLAG_RW, 
 	&null_bug_bypass, 0, "");
 
-static int	null_bypass __P((struct vop_generic_args *ap));
+int		null_bypass __P((struct vop_generic_args *ap));
 static int	null_bwrite __P((struct vop_bwrite_args *ap));
 static int	null_getattr __P((struct vop_getattr_args *ap));
 static int	null_inactive __P((struct vop_inactive_args *ap));
@@ -211,7 +225,7 @@ static int	null_strategy __P((struct vop_strategy_args *ap));
  * - all mapped vnodes are of our vnode-type (NEEDSWORK:
  *   problems on rmdir'ing mount points and renaming?)
  */
-static int
+int
 null_bypass(ap)
 	struct vop_generic_args /* {
 		struct vnodeop_desc *a_desc;
@@ -254,7 +268,8 @@ null_bypass(ap)
 		 * are of our type.  Check for and don't map any
 		 * that aren't.  (We must always map first vp or vclean fails.)
 		 */
-		if (i && (*this_vp_p)->v_op != null_vnodeop_p) {
+		if (i && (*this_vp_p == NULL ||
+		    (*this_vp_p)->v_op != null_vnodeop_p)) {
 			old_vps[i] = NULL;
 		} else {
 			old_vps[i] = *this_vp_p;
@@ -317,6 +332,105 @@ null_bypass(ap)
 	return (error);
 }
 
+/*
+ * We have to carry on the locking protocol on the null layer vnodes
+ * as we progress through the tree. We also have to enforce read-only
+ * if this layer is mounted read-only.
+ */
+static int
+null_lookup(ap)
+	struct vop_lookup_args /* {
+		struct vnode * a_dvp;
+		struct vnode ** a_vpp;
+		struct componentname * a_cnp;
+	} */ *ap;
+{
+	struct componentname *cnp = ap->a_cnp;
+	struct proc *p = cnp->cn_proc;
+	int flags = cnp->cn_flags;
+	struct vop_lock_args lockargs;
+	struct vop_unlock_args unlockargs;
+	struct vnode *dvp, *vp;
+	int error;
+
+	if ((flags & ISLASTCN) && (ap->a_dvp->v_mount->mnt_flag & MNT_RDONLY) &&
+	    (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME))
+		return (EROFS);
+	error = null_bypass(ap);
+	if (error == EJUSTRETURN && (flags & ISLASTCN) &&
+	    (ap->a_dvp->v_mount->mnt_flag & MNT_RDONLY) &&
+	    (cnp->cn_nameiop == CREATE || cnp->cn_nameiop == RENAME))
+		error = EROFS;
+	/*
+	 * We must do the same locking and unlocking at this layer as 
+	 * is done in the layers below us. We could figure this out 
+	 * based on the error return and the LASTCN, LOCKPARENT, and
+	 * LOCKLEAF flags. However, it is more expidient to just find 
+	 * out the state of the lower level vnodes and set ours to the
+	 * same state.
+	 */
+	dvp = ap->a_dvp;
+	vp = *ap->a_vpp;
+	if (dvp == vp)
+		return (error);
+	if (!VOP_ISLOCKED(dvp)) {
+		unlockargs.a_vp = dvp;
+		unlockargs.a_flags = 0;
+		unlockargs.a_p = p;
+		vop_nounlock(&unlockargs);
+	}
+	if (vp != NULL && VOP_ISLOCKED(vp)) {
+		lockargs.a_vp = vp;
+		lockargs.a_flags = LK_SHARED;
+		lockargs.a_p = p;
+		vop_nolock(&lockargs);
+	}
+	return (error);
+}
+
+/*
+ * Setattr call. Disallow write attempts if the layer is mounted read-only.
+ */
+int
+null_setattr(ap)
+	struct vop_setattr_args /* {
+		struct vnodeop_desc *a_desc;
+		struct vnode *a_vp;
+		struct vattr *a_vap;
+		struct ucred *a_cred;
+		struct proc *a_p;
+	} */ *ap;
+{
+	struct vnode *vp = ap->a_vp;
+	struct vattr *vap = ap->a_vap;
+
+  	if ((vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL ||
+	    vap->va_gid != (gid_t)VNOVAL || vap->va_atime.ts_sec != VNOVAL ||
+	    vap->va_mtime.ts_sec != VNOVAL || vap->va_mode != (mode_t)VNOVAL) &&
+	    (vp->v_mount->mnt_flag & MNT_RDONLY))
+		return (EROFS);
+	if (vap->va_size != VNOVAL) {
+ 		switch (vp->v_type) {
+ 		case VDIR:
+ 			return (EISDIR);
+ 		case VCHR:
+ 		case VBLK:
+ 		case VSOCK:
+ 		case VFIFO:
+			return (0);
+		case VREG:
+		case VLNK:
+ 		default:
+			/*
+			 * Disallow write attempts if the filesystem is
+			 * mounted read-only.
+			 */
+			if (vp->v_mount->mnt_flag & MNT_RDONLY)
+				return (EROFS);
+		}
+	}
+	return (null_bypass(ap));
+}
 
 /*
  *  We handle getattr only to change the fsid.
@@ -331,19 +445,90 @@ null_getattr(ap)
 	} */ *ap;
 {
 	int error;
-	error = null_bypass(ap);
-	if (error)
+
+	if (error = null_bypass(ap))
 		return (error);
 	/* Requires that arguments be restored. */
 	ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];
 	return (0);
 }
 
-
 static int
+null_access(ap)
+	struct vop_access_args /* {
+		struct vnode *a_vp;
+		int  a_mode;
+		struct ucred *a_cred;
+		struct proc *a_p;
+	} */ *ap;
+{
+	struct vnode *vp = ap->a_vp;
+	mode_t mode = ap->a_mode;
+
+	/*
+	 * Disallow write attempts on read-only layers;
+	 * unless the file is a socket, fifo, or a block or
+	 * character device resident on the file system.
+	 */
+	if (mode & VWRITE) {
+		switch (vp->v_type) {
+		case VDIR:
+		case VLNK:
+		case VREG:
+			if (vp->v_mount->mnt_flag & MNT_RDONLY)
+				return (EROFS);
+			break;
+		}
+	}
+	return (null_bypass(ap));
+}
+
+/*
+ * We need to process our own vnode lock and then clear the
+ * interlock flag as it applies only to our vnode, not the
+ * vnodes below us on the stack.
+ */
+int
+null_lock(ap)
+	struct vop_lock_args /* {
+		struct vnode *a_vp;
+		int a_flags;
+		struct proc *a_p;
+	} */ *ap;
+{
+
+	vop_nolock(ap);
+	if ((ap->a_flags & LK_TYPE_MASK) == LK_DRAIN)
+		return (0);
+	ap->a_flags &= ~LK_INTERLOCK;
+	return (null_bypass(ap));
+}
+
+/*
+ * We need to process our own vnode unlock and then clear the
+ * interlock flag as it applies only to our vnode, not the
+ * vnodes below us on the stack.
+ */
+int
+null_unlock(ap)
+	struct vop_unlock_args /* {
+		struct vnode *a_vp;
+		int a_flags;
+		struct proc *a_p;
+	} */ *ap;
+{
+	struct vnode *vp = ap->a_vp;
+
+	vop_nounlock(ap);
+	ap->a_flags &= ~LK_INTERLOCK;
+	return (null_bypass(ap));
+}
+
+int
 null_inactive(ap)
 	struct vop_inactive_args /* {
 		struct vnode *a_vp;
+		struct proc *a_p;
 	} */ *ap;
 {
 	/*
@@ -358,6 +543,7 @@ null_inactive(ap)
 	 * like they do in the name lookup cache code.
 	 * That's too much work for now.
 	 */
+	VOP_UNLOCK(ap->a_vp, 0, ap->a_p);
 	return (0);
 }
 
@@ -365,6 +551,7 @@ static int
 null_reclaim(ap)
 	struct vop_reclaim_args /* {
 		struct vnode *a_vp;
+		struct proc *a_p;
 	} */ *ap;
 {
 	struct vnode *vp = ap->a_vp;
@@ -377,14 +564,13 @@ null_reclaim(ap)
 	 */
 	/* After this assignment, this node will not be re-used. */
 	xp->null_lowervp = NULL;
-	remque(xp);
+	LIST_REMOVE(xp, null_hash);
 	FREE(vp->v_data, M_TEMP);
 	vp->v_data = NULL;
 	vrele (lowervp);
 	return (0);
 }
 
-
 static int
 null_print(ap)
 	struct vop_print_args /* {
@@ -396,7 +582,6 @@ null_print(ap)
 	return (0);
 }
 
-
 /*
  * XXX - vop_strategy must be hand coded because it has no
  * vnode in its arguments.
@@ -422,7 +607,6 @@ null_strategy(ap)
 	return (error);
 }
 
-
 /*
  * XXX - like vop_strategy, vop_bwrite must be hand coded because it has no
  * vnode in its arguments.
@@ -455,7 +639,12 @@ vop_t **null_vnodeop_p;
 static struct vnodeopv_entry_desc null_vnodeop_entries[] = {
 	{ &vop_default_desc, (vop_t *)null_bypass },
 
+	{ &vop_lookup_desc, (vop_t *)null_lookup },
+	{ &vop_setattr_desc, (vop_t *)null_setattr },
 	{ &vop_getattr_desc, (vop_t *)null_getattr },
+	{ &vop_access_desc, (vop_t *)null_access },
+	{ &vop_lock_desc, (vop_t *)null_lock },
+	{ &vop_unlock_desc, (vop_t *)null_unlock },
 	{ &vop_inactive_desc, (vop_t *)null_inactive },
 	{ &vop_reclaim_desc, (vop_t *)null_reclaim },
 	{ &vop_print_desc, (vop_t *)null_print },