[src/trunk]: src/sys/fs/union VOP_ABORTOP() has no specific lock requirements...

[hannken <hannken%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/cc95c144f84f
branches:  trunk
changeset: 771219:cc95c144f84f
user:      hannken <hannken%NetBSD.org@localhost>
date:      Mon Nov 14 18:42:57 2011 +0000

description:
VOP_ABORTOP() has no specific lock requirements so there is no need
to force locked vnodes here.  It should be impossible to come here
with a nil upper node.

Relock the directory vnode after copyup.  A locked union node with an
unlocked upper vnode can no longer exist so make FIXUP() an assertion.

diffstat:

 sys/fs/union/union_vnops.c |  44 +++++++++++---------------------------------
 1 files changed, 11 insertions(+), 33 deletions(-)

diffs (91 lines):

diff -r f21a639794dc -r cc95c144f84f sys/fs/union/union_vnops.c
--- a/sys/fs/union/union_vnops.c        Mon Nov 14 18:38:13 2011 +0000
+++ b/sys/fs/union/union_vnops.c        Mon Nov 14 18:42:57 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: union_vnops.c,v 1.47 2011/10/18 09:22:53 hannken Exp $ */
+/*     $NetBSD: union_vnops.c,v 1.48 2011/11/14 18:42:57 hannken Exp $ */
 
 /*
  * Copyright (c) 1992, 1993, 1994, 1995
@@ -72,7 +72,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: union_vnops.c,v 1.47 2011/10/18 09:22:53 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: union_vnops.c,v 1.48 2011/11/14 18:42:57 hannken Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -134,7 +134,6 @@
 int union_putpages(void *);
 int union_kqfilter(void *);
 
-static void union_fixup(struct union_node *);
 static int union_lookup1(struct vnode *, struct vnode **,
                              struct vnode **, struct componentname *);
 
@@ -190,23 +189,12 @@
 const struct vnodeopv_desc union_vnodeop_opv_desc =
        { &union_vnodeop_p, union_vnodeop_entries };
 
-#define FIXUP(un) { \
-       if (((un)->un_flags & UN_ULOCK) == 0) { \
-               union_fixup(un); \
-       } \
-}
+#define FIXUP(un) \
+       KASSERT(((un)->un_flags & UN_ULOCK) == UN_ULOCK)
 #define NODE_IS_SPECIAL(vp) \
        ((vp)->v_type == VBLK || (vp)->v_type == VCHR || \
        (vp)->v_type == VSOCK || (vp)->v_type == VFIFO)
 
-static void
-union_fixup(struct union_node *un)
-{
-
-       vn_lock(un->un_uppervp, LK_EXCLUSIVE | LK_RETRY);
-       un->un_flags |= UN_ULOCK;
-}
-
 static int
 union_lookup1(struct vnode *udvp, struct vnode **dvpp, struct vnode **vpp,
        struct componentname *cnp)
@@ -1248,6 +1236,9 @@
                        }
                        error = union_copyup(un, 1, cnp->cn_cred, curlwp);
                        if (dun->un_uppervp == un->un_dirvp) {
+                               vn_lock(dun->un_uppervp,
+                                   LK_EXCLUSIVE | LK_RETRY);
+                               dun->un_flags |= UN_ULOCK;
                                /*
                                 * During copyup, we dropped the lock on the
                                 * dir and invalidated any saved namei lookup
@@ -1583,24 +1574,11 @@
                struct vnode *a_dvp;
                struct componentname *a_cnp;
        } */ *ap = v;
-       int error;
-       struct vnode *vp = OTHERVP(ap->a_dvp);
-       struct union_node *un = VTOUNION(ap->a_dvp);
-       int islocked = un->un_flags & UN_LOCKED;
-       int dolock = (vp == LOWERVP(ap->a_dvp));
+
+       KASSERT(UPPERVP(ap->a_dvp) != NULL);
 
-       if (islocked) {
-               if (dolock)
-                       vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
-               else
-                       FIXUP(VTOUNION(ap->a_dvp));
-       }
-       ap->a_dvp = vp;
-       error = VCALL(vp, VOFFSET(vop_abortop), ap);
-       if (islocked && dolock)
-               VOP_UNLOCK(vp);
-
-       return (error);
+       ap->a_dvp = UPPERVP(ap->a_dvp);
+       return VCALL(ap->a_dvp, VOFFSET(vop_abortop), ap);
 }
 
 int