From 162ce1a75f68a8b2b1c107fe4a8a30973c8ad0ba Mon Sep 17 00:00:00 2001
From: Pawel Jakub Dawidek <pjd@FreeBSD.org>
Date: Sat, 4 Nov 2006 23:59:51 +0000
Subject: [PATCH] When the source and destination objects for VOP_RENAME() are
 the same, POSIX advice to just ignore the operation and return 0. We already
 handle this case in kern_rename(), but don't give bad example - the source is
 not removed.

---
 share/man/man9/VOP_RENAME.9 | 33 ++++++---------------------------
 1 file changed, 6 insertions(+), 27 deletions(-)

diff --git a/share/man/man9/VOP_RENAME.9 b/share/man/man9/VOP_RENAME.9
index 2d8b4508bc85..4c2e58a65a3c 100644
--- a/share/man/man9/VOP_RENAME.9
+++ b/share/man/man9/VOP_RENAME.9
@@ -104,34 +104,13 @@ vop_rename(struct vnode *fdvp, struct vnode *fvp, struct componentname *fcnp,
     }
 
     /*
-     * Check if just deleting a link name.
+     * POSIX: "If the old argument and the new argument
+     * both refer to links to the same existing file,
+     * the rename() function shall return successfully
+     * and perform no other action."
+     * The upper layers already handle this case.
      */
-    if (fvp == tvp) {
-	if (fvp->v_type == VDIR) {
-	    error = EINVAL;
-	    goto abortit;
-	}
-
-	/*
-	 * Release destination.
-	 */
-	vput(tdvp);
-	vput(tvp);
-
-	/*
-	 * Delete source.  Pretty bizarre stuff.
-	 */
-	vrele(fdvp);
-	vrele(fvp);
-	fcnp->cn_flags &= ~MODMASK;
-	fcnp->cn_flags |= LOCKPARENT | LOCKLEAF;
-	fcnp->cn_nameiop = DELETE;
-	VREF(fdvp);
-	error = relookup(fdvp, &fvp, fcnp);
-	if (error == 0)
-	    vrele(fdvp);
-	return VOP_REMOVE(fdvp, fvp, fcnp);
-    }
+    KASSERT(fvp != tvp, ("vop_rename: source and destination are the same"));
 
     if (fvp is immutable) {
 	error = EPERM;