Improve and revise fixes for locking violation.

Obtained from:	NetBSD/pc98

4 files changed, 104 insertions, 66 deletions

diff --git a/sys/fs/unionfs/union_vfsops.c b/sys/fs/unionfs/union_vfsops.c
index 753afd6..90da301 100644
--- a/sys/fs/unionfs/union_vfsops.c
+++ b/sys/fs/unionfs/union_vfsops.c
@@ -35,7 +35,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)union_vfsops.c	8.20 (Berkeley) 5/20/95
- * $Id: union_vfsops.c,v 1.21 1997/10/12 20:24:57 phk Exp $
+ * $Id: union_vfsops.c,v 1.22 1997/11/18 15:07:35 phk Exp $
  */
 
 /*
@@ -132,12 +132,9 @@ union_mount(mp, path, data, ndp, p)
 
 	/*
 	 * Unlock lower node to avoid deadlock.
-	 * (XXX) VOP_ISLOCKED is needed?
 	 */
-	if ((lowerrootvp->v_op == union_vnodeop_p) && VOP_ISLOCKED(lowerrootvp)) {
+	if (lowerrootvp->v_op == union_vnodeop_p)
 		VOP_UNLOCK(lowerrootvp, 0, p);
-		islowerunlocked = 1;
-	}
 
 	/*
 	 * Find upper node.
@@ -146,11 +143,7 @@ union_mount(mp, path, data, ndp, p)
 	       UIO_USERSPACE, args.target, p);
 
 	error = namei(ndp);
-	/*
-	 * Re-lock vnode.
-	 * (XXX) VOP_ISLOCKED is needed?
-	 */
-	if (islowerunlocked && !VOP_ISLOCKED(lowerrootvp))
+	if (lowerrootvp->v_op == union_vnodeop_p)
 		vn_lock(lowerrootvp, LK_EXCLUSIVE | LK_RETRY, p);
 	if (error)
 		goto bad;
@@ -404,27 +397,24 @@ union_root(mp, vpp)
 	struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
 	int error;
 	int loselock;
+	int lockadj = 0;
+
+	if (um->um_lowervp && um->um_op != UNMNT_BELOW &&
+		VOP_ISLOCKED(um->um_lowervp)) {
+		VREF(um->um_lowervp);
+		VOP_UNLOCK(um->um_lowervp, 0, p);
+		lockadj = 1;
+	}
 
 	/*
 	 * Return locked reference to root.
 	 */
 	VREF(um->um_uppervp);
 	if ((um->um_op == UNMNT_BELOW) &&
-	     VOP_ISLOCKED(um->um_uppervp)) {
+	    VOP_ISLOCKED(um->um_uppervp)) {
 		loselock = 1;
 	} else {
-		if (VOP_ISLOCKED(um->um_uppervp)) {
-			/*
-			 * XXX
-			 * Should we check type of node?
-			 */
-#ifdef DIAGNOSTIC
-			printf("union_root: multi union mount?");
-#endif
-			vrele(um->um_uppervp);
-			return EDEADLK;
-		} else
-			vn_lock(um->um_uppervp, LK_EXCLUSIVE | LK_RETRY, p);
+		vn_lock(um->um_uppervp, LK_EXCLUSIVE | LK_RETRY, p);
 		loselock = 0;
 	}
 	if (um->um_lowervp)
@@ -448,6 +438,10 @@ union_root(mp, vpp)
 		if (loselock)
 			VTOUNION(*vpp)->un_flags &= ~UN_ULOCK;
 	}
+	if (lockadj) {
+		vn_lock(um->um_lowervp, LK_EXCLUSIVE | LK_RETRY, p);
+		vrele(um->um_lowervp);
+	}
 
 	return (error);
 }
diff --git a/sys/fs/unionfs/union_vnops.c b/sys/fs/unionfs/union_vnops.c
index 83dcb3e..434b6a0 100644
--- a/sys/fs/unionfs/union_vnops.c
+++ b/sys/fs/unionfs/union_vnops.c
@@ -35,7 +35,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)union_vnops.c	8.32 (Berkeley) 6/23/95
- * $Id: union_vnops.c,v 1.45 1997/10/16 20:32:30 phk Exp $
+ * $Id: union_vnops.c,v 1.46 1997/10/26 20:55:26 phk Exp $
  */
 
 #include <sys/param.h>
@@ -244,6 +244,13 @@ union_lookup(ap)
 	lowervp = NULLVP;
 	iswhiteout = 0;
 
+	if (cnp->cn_flags & ISDOTDOT) {
+		if (upperdvp != NULL)
+			VREF(upperdvp);
+		if (lowerdvp != NULL)
+			VREF(lowerdvp);
+	}
+
 	/*
 	 * do the lookup in the upper level.
 	 * if that level comsumes additional pathnames,
@@ -305,7 +312,8 @@ union_lookup(ap)
 			*ap->a_vpp = uppervp;
 			if (!lockparent)
 				cnp->cn_flags &= ~LOCKPARENT;
-			return (uerror);
+			error = uerror;
+			goto out;
 		}
 		if (uerror == ENOENT || uerror == EJUSTRETURN) {
 			if (cnp->cn_flags & ISWHITEOUT) {
@@ -371,7 +379,8 @@ union_lookup(ap)
 			*ap->a_vpp = lowervp;
 			if (!lockparent)
 				cnp->cn_flags &= ~LOCKPARENT;
-			return (lerror);
+			error = lerror;
+			goto out;
 		}
 	} else {
 		lerror = ENOENT;
@@ -416,7 +425,8 @@ union_lookup(ap)
 
 	/* case 1. */
 	if ((uerror != 0) && (lerror != 0)) {
-		return (uerror);
+		error = uerror;
+		goto out;
 	}
 
 	/* case 2. */
@@ -433,7 +443,8 @@ union_lookup(ap)
 					vput(lowervp);
 					lowervp = NULLVP;
 				}
-				return (uerror);
+				error = uerror;
+				goto out;
 			}
 		}
 	}
@@ -463,6 +474,14 @@ union_lookup(ap)
 #endif
 	}
 
+out:
+    if (cnp->cn_flags & ISDOTDOT) {
+        if (upperdvp != NULL)
+            vrele(upperdvp);
+        if (lowerdvp != NULL)
+            vrele(lowerdvp);
+    }
+
 	return (error);
 }
 
@@ -1015,12 +1034,18 @@ union_fsync(ap)
 		un = VTOUNION(ap->a_vp);
 		if (dolock)
 			vn_lock(targetvp, LK_EXCLUSIVE | LK_RETRY, p);
-		else if ((un->un_flags & UN_ULOCK) == 0 &&
-				 VOP_ISLOCKED(targetvp) == 0) {
-			isupperlocked = 1;
-			vn_lock(targetvp, LK_EXCLUSIVE | LK_RETRY, p);
-			un->un_flags |= UN_ULOCK;
+		else  {
+			un = VTOUNION(ap->a_vp);
+			if ((un->un_flags & UN_ULOCK) == 0 &&
+			    targetvp->v_data != NULL &&
+			    ((struct lock *)targetvp->v_data)->lk_lockholder
+			        == curproc->p_pid &&
+			    VOP_ISLOCKED(targetvp) != 0)
+				return 0;   /* XXX */
+
+			FIXUP(un, p);
 		}
+
 		error = VOP_FSYNC(targetvp, ap->a_cred, ap->a_waitfor, p);
 		if (dolock)
 			VOP_UNLOCK(targetvp, 0, p);
diff --git a/sys/miscfs/union/union_vfsops.c b/sys/miscfs/union/union_vfsops.c
index 753afd6..90da301 100644
--- a/sys/miscfs/union/union_vfsops.c
+++ b/sys/miscfs/union/union_vfsops.c
@@ -35,7 +35,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)union_vfsops.c	8.20 (Berkeley) 5/20/95
- * $Id: union_vfsops.c,v 1.21 1997/10/12 20:24:57 phk Exp $
+ * $Id: union_vfsops.c,v 1.22 1997/11/18 15:07:35 phk Exp $
  */
 
 /*
@@ -132,12 +132,9 @@ union_mount(mp, path, data, ndp, p)
 
 	/*
 	 * Unlock lower node to avoid deadlock.
-	 * (XXX) VOP_ISLOCKED is needed?
 	 */
-	if ((lowerrootvp->v_op == union_vnodeop_p) && VOP_ISLOCKED(lowerrootvp)) {
+	if (lowerrootvp->v_op == union_vnodeop_p)
 		VOP_UNLOCK(lowerrootvp, 0, p);
-		islowerunlocked = 1;
-	}
 
 	/*
 	 * Find upper node.
@@ -146,11 +143,7 @@ union_mount(mp, path, data, ndp, p)
 	       UIO_USERSPACE, args.target, p);
 
 	error = namei(ndp);
-	/*
-	 * Re-lock vnode.
-	 * (XXX) VOP_ISLOCKED is needed?
-	 */
-	if (islowerunlocked && !VOP_ISLOCKED(lowerrootvp))
+	if (lowerrootvp->v_op == union_vnodeop_p)
 		vn_lock(lowerrootvp, LK_EXCLUSIVE | LK_RETRY, p);
 	if (error)
 		goto bad;
@@ -404,27 +397,24 @@ union_root(mp, vpp)
 	struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
 	int error;
 	int loselock;
+	int lockadj = 0;
+
+	if (um->um_lowervp && um->um_op != UNMNT_BELOW &&
+		VOP_ISLOCKED(um->um_lowervp)) {
+		VREF(um->um_lowervp);
+		VOP_UNLOCK(um->um_lowervp, 0, p);
+		lockadj = 1;
+	}
 
 	/*
 	 * Return locked reference to root.
 	 */
 	VREF(um->um_uppervp);
 	if ((um->um_op == UNMNT_BELOW) &&
-	     VOP_ISLOCKED(um->um_uppervp)) {
+	    VOP_ISLOCKED(um->um_uppervp)) {
 		loselock = 1;
 	} else {
-		if (VOP_ISLOCKED(um->um_uppervp)) {
-			/*
-			 * XXX
-			 * Should we check type of node?
-			 */
-#ifdef DIAGNOSTIC
-			printf("union_root: multi union mount?");
-#endif
-			vrele(um->um_uppervp);
-			return EDEADLK;
-		} else
-			vn_lock(um->um_uppervp, LK_EXCLUSIVE | LK_RETRY, p);
+		vn_lock(um->um_uppervp, LK_EXCLUSIVE | LK_RETRY, p);
 		loselock = 0;
 	}
 	if (um->um_lowervp)
@@ -448,6 +438,10 @@ union_root(mp, vpp)
 		if (loselock)
 			VTOUNION(*vpp)->un_flags &= ~UN_ULOCK;
 	}
+	if (lockadj) {
+		vn_lock(um->um_lowervp, LK_EXCLUSIVE | LK_RETRY, p);
+		vrele(um->um_lowervp);
+	}
 
 	return (error);
 }
diff --git a/sys/miscfs/union/union_vnops.c b/sys/miscfs/union/union_vnops.c
index 83dcb3e..434b6a0 100644
--- a/sys/miscfs/union/union_vnops.c
+++ b/sys/miscfs/union/union_vnops.c
@@ -35,7 +35,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)union_vnops.c	8.32 (Berkeley) 6/23/95
- * $Id: union_vnops.c,v 1.45 1997/10/16 20:32:30 phk Exp $
+ * $Id: union_vnops.c,v 1.46 1997/10/26 20:55:26 phk Exp $
  */
 
 #include <sys/param.h>
@@ -244,6 +244,13 @@ union_lookup(ap)
 	lowervp = NULLVP;
 	iswhiteout = 0;
 
+	if (cnp->cn_flags & ISDOTDOT) {
+		if (upperdvp != NULL)
+			VREF(upperdvp);
+		if (lowerdvp != NULL)
+			VREF(lowerdvp);
+	}
+
 	/*
 	 * do the lookup in the upper level.
 	 * if that level comsumes additional pathnames,
@@ -305,7 +312,8 @@ union_lookup(ap)
 			*ap->a_vpp = uppervp;
 			if (!lockparent)
 				cnp->cn_flags &= ~LOCKPARENT;
-			return (uerror);
+			error = uerror;
+			goto out;
 		}
 		if (uerror == ENOENT || uerror == EJUSTRETURN) {
 			if (cnp->cn_flags & ISWHITEOUT) {
@@ -371,7 +379,8 @@ union_lookup(ap)
 			*ap->a_vpp = lowervp;
 			if (!lockparent)
 				cnp->cn_flags &= ~LOCKPARENT;
-			return (lerror);
+			error = lerror;
+			goto out;
 		}
 	} else {
 		lerror = ENOENT;
@@ -416,7 +425,8 @@ union_lookup(ap)
 
 	/* case 1. */
 	if ((uerror != 0) && (lerror != 0)) {
-		return (uerror);
+		error = uerror;
+		goto out;
 	}
 
 	/* case 2. */
@@ -433,7 +443,8 @@ union_lookup(ap)
 					vput(lowervp);
 					lowervp = NULLVP;
 				}
-				return (uerror);
+				error = uerror;
+				goto out;
 			}
 		}
 	}
@@ -463,6 +474,14 @@ union_lookup(ap)
 #endif
 	}
 
+out:
+    if (cnp->cn_flags & ISDOTDOT) {
+        if (upperdvp != NULL)
+            vrele(upperdvp);
+        if (lowerdvp != NULL)
+            vrele(lowerdvp);
+    }
+
 	return (error);
 }
 
@@ -1015,12 +1034,18 @@ union_fsync(ap)
 		un = VTOUNION(ap->a_vp);
 		if (dolock)
 			vn_lock(targetvp, LK_EXCLUSIVE | LK_RETRY, p);
-		else if ((un->un_flags & UN_ULOCK) == 0 &&
-				 VOP_ISLOCKED(targetvp) == 0) {
-			isupperlocked = 1;
-			vn_lock(targetvp, LK_EXCLUSIVE | LK_RETRY, p);
-			un->un_flags |= UN_ULOCK;
+		else  {
+			un = VTOUNION(ap->a_vp);
+			if ((un->un_flags & UN_ULOCK) == 0 &&
+			    targetvp->v_data != NULL &&
+			    ((struct lock *)targetvp->v_data)->lk_lockholder
+			        == curproc->p_pid &&
+			    VOP_ISLOCKED(targetvp) != 0)
+				return 0;   /* XXX */
+
+			FIXUP(un, p);
 		}
+
 		error = VOP_FSYNC(targetvp, ap->a_cred, ap->a_waitfor, p);
 		if (dolock)
 			VOP_UNLOCK(targetvp, 0, p);