From ee55350db0df9355dc355166596611b59aa29ed1 Mon Sep 17 00:00:00 2001
From: jeff <jeff@FreeBSD.org>
Date: Wed, 13 Apr 2005 10:57:13 +0000
Subject:  - Further simplify lookup; Force all filesystems to relock in the
 DOTDOT    case.  There are bugs in some which didn't unlock in the ISDOTDOT
 case    to begin with that need to be addressed seperately.  This simplifies 
   things anyway.  - Fix relookup() to prevent it from vrele()'ing the dvp
 while the vp    is locked.  Catch up to other lookup changes.

Sponsored by:	Isilon Systems, Inc.
Reported by:	Peter Wemm
---
 sys/kern/vfs_lookup.c | 53 ++++++++++++++++++++++-----------------------------
 1 file changed, 23 insertions(+), 30 deletions(-)

(limited to 'sys/kern')

diff --git a/sys/kern/vfs_lookup.c b/sys/kern/vfs_lookup.c
index ff8ba2d..eaf2fcc 100644
--- a/sys/kern/vfs_lookup.c
+++ b/sys/kern/vfs_lookup.c
@@ -592,12 +592,6 @@ unionlookup:
 	printf("found\n");
 #endif
 	/*
-	 * In the DOTDOT case dp is unlocked, we relock it here even if we
-	 * may not need it to simplify the code below.
-	 */
-	if (cnp->cn_flags & ISDOTDOT)
-		vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td);
-	/*
 	 * Take into account any additional components consumed by
 	 * the underlying filesystem.
 	 */
@@ -746,6 +740,7 @@ relookup(dvp, vpp, cnp)
 	 * Setup: break out flag bits into variables.
 	 */
 	wantparent = cnp->cn_flags & (LOCKPARENT|WANTPARENT);
+	KASSERT(wantparent, ("relookup: parent not wanted."));
 	rdonly = cnp->cn_flags & RDONLY;
 	cnp->cn_flags &= ~ISSYMLINK;
 	dp = dvp;
@@ -826,46 +821,44 @@ relookup(dvp, vpp, cnp)
 		 */
 		return (0);
 	}
-	/*
-	 * In the DOTDOT case dp is unlocked, we may have to relock it if
-	 * LOCKPARENT is set.  Otherwise, unlock the parent.
-	 */
-	if ((cnp->cn_flags & (ISDOTDOT | LOCKPARENT)) ==
-	    (ISDOTDOT | LOCKPARENT))
-		vn_lock(dp, LK_EXCLUSIVE | LK_RETRY, td);
-	else if ((cnp->cn_flags & (ISDOTDOT | LOCKPARENT)) == 0 && dp != *vpp)
-		VOP_UNLOCK(dp, 0, td);
 	dp = *vpp;
 
 	/*
-	 * Check for symbolic link
-	 */
-	KASSERT(dp->v_type != VLNK || !(cnp->cn_flags & FOLLOW),
-	    ("relookup: symlink found.\n"));
-
-	/*
 	 * Disallow directory write attempts on read-only filesystems.
 	 */
 	if (rdonly &&
 	    (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
+		printf("this is it?\n");
+		if (dvp == dp)
+			vrele(dvp);
+		else
+			vput(dvp);
 		error = EROFS;
-		goto bad2;
+		goto bad;
 	}
+	/*
+	 * Set the parent lock/ref state to the requested state.
+	 */
+	if ((cnp->cn_flags & LOCKPARENT) == 0 && dvp != dp) {
+		if (wantparent)
+			VOP_UNLOCK(dvp, 0, td);
+		else
+			vput(dvp);
+	} else if (!wantparent)
+		vrele(dvp);
+	/*
+	 * Check for symbolic link
+	 */
+	KASSERT(dp->v_type != VLNK || !(cnp->cn_flags & FOLLOW),
+	    ("relookup: symlink found.\n"));
+
 	/* ASSERT(dvp == ndp->ni_startdir) */
 	if (cnp->cn_flags & SAVESTART)
 		VREF(dvp);
 	
-	if (!wantparent)
-		vrele(dvp);
-
 	if ((cnp->cn_flags & LOCKLEAF) == 0)
 		VOP_UNLOCK(dp, 0, td);
 	return (0);
-
-bad2:
-	if (cnp->cn_flags & LOCKPARENT)
-		VOP_UNLOCK(dvp, 0, td);
-	vrele(dvp);
 bad:
 	vput(dp);
 	*vpp = NULL;
-- 
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