[src/trunk]: src/sys/miscfs/genfs Restructure layer_lock() to always lock bef...

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

details:   https://anonhg.NetBSD.org/src/rev/0868af7ba5d1
branches:  trunk
changeset: 794334:0868af7ba5d1
user:      hannken <hannken%NetBSD.org@localhost>
date:      Wed Mar 12 09:39:23 2014 +0000

description:
Restructure layer_lock() to always lock before testing for dead node.
Use ISSET() to test flags, add assertions.

diffstat:

 sys/miscfs/genfs/layer_vnops.c |  34 +++++++++++++++++++++-------------
 1 files changed, 21 insertions(+), 13 deletions(-)

diffs (64 lines):

diff -r 58c82e7b84c9 -r 0868af7ba5d1 sys/miscfs/genfs/layer_vnops.c
--- a/sys/miscfs/genfs/layer_vnops.c    Wed Mar 12 09:38:51 2014 +0000
+++ b/sys/miscfs/genfs/layer_vnops.c    Wed Mar 12 09:39:23 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: layer_vnops.c,v 1.55 2014/02/27 16:51:38 hannken Exp $ */
+/*     $NetBSD: layer_vnops.c,v 1.56 2014/03/12 09:39:23 hannken Exp $ */
 
 /*
  * Copyright (c) 1999 National Aeronautics & Space Administration
@@ -170,7 +170,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: layer_vnops.c,v 1.55 2014/02/27 16:51:38 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: layer_vnops.c,v 1.56 2014/03/12 09:39:23 hannken Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -718,15 +718,23 @@
        int flags = ap->a_flags;
        int error;
 
-       if ((flags & LK_NOWAIT) != 0) {
-               if (!mutex_tryenter(vp->v_interlock))
-                       return EBUSY;
-               if ((vp->v_iflag & (VI_XLOCK | VI_CLEAN)) != 0) {
+       if (ISSET(flags, LK_NOWAIT)) {
+               error = VOP_LOCK(lowervp, flags);
+               if (error)
+                       return error;
+               if (mutex_tryenter(vp->v_interlock)) {
+                       if (ISSET(vp->v_iflag, VI_XLOCK))
+                               error = EBUSY;
+                       else if (ISSET(vp->v_iflag, VI_CLEAN))
+                               error = ENOENT;
+                       else
+                               error = 0;
                        mutex_exit(vp->v_interlock);
-                       return EBUSY;
-               }
-               mutex_exit(vp->v_interlock);
-               return VOP_LOCK(lowervp, flags);
+               } else
+                       error = EBUSY;
+               if (error)
+                       VOP_UNLOCK(lowervp);
+               return error;
        }
 
        error = VOP_LOCK(lowervp, flags);
@@ -734,10 +742,10 @@
                return error;
 
        mutex_enter(vp->v_interlock);
-       if ((vp->v_iflag & (VI_XLOCK | VI_CLEAN)) != 0) {
+       if (ISSET(vp->v_iflag, VI_XLOCK) || ISSET(vp->v_iflag, VI_CLEAN)) {
                VOP_UNLOCK(lowervp);
-               if ((vp->v_iflag & VI_XLOCK))
-                       vwait(vp, VI_XLOCK);
+               vwait(vp, VI_XLOCK);
+               KASSERT(ISSET(vp->v_iflag, VI_CLEAN));
                mutex_exit(vp->v_interlock);
                return ENOENT;
        }