svn commit: r232643 - stable/9/sys/fs/nullfs

[Konstantin Belousov]

Author: kib
Date: Wed Mar  7 07:59:30 2012
New Revision: 232643
URL: http://svn.freebsd.org/changeset/base/232643

Log:
  MFC r232299:
  Move the code to destroy half-contructed nullfs vnode into helper
  function null_destroy_proto() from null_insmntque_dtr(). Also
  apply null_destroy_proto() in null_nodeget() when we raced and a vnode
  is found in the hash, so the currently allocated protonode shall be
  destroyed.
  
  Lock the vnode interlock around reassigning the v_vnlock.
  
  MFC r232383:
  Do not expose unlocked unconstructed nullfs vnode on mount list.
  Lock the native nullfs vnode lock before switching the locks.

Modified:
  stable/9/sys/fs/nullfs/null_subr.c
Directory Properties:
  stable/9/sys/   (props changed)

Modified: stable/9/sys/fs/nullfs/null_subr.c
==============================================================================
--- stable/9/sys/fs/nullfs/null_subr.c	Wed Mar  7 07:55:35 2012	(r232642)
+++ stable/9/sys/fs/nullfs/null_subr.c	Wed Mar  7 07:59:30 2012	(r232643)
@@ -169,17 +169,26 @@ null_hashins(mp, xp)
 }
 
 static void
-null_insmntque_dtr(struct vnode *vp, void *xp)
+null_destroy_proto(struct vnode *vp, void *xp)
 {
 
-	vput(((struct null_node *)xp)->null_lowervp);
+	lockmgr(&vp->v_lock, LK_EXCLUSIVE, NULL);
+	VI_LOCK(vp);
 	vp->v_data = NULL;
 	vp->v_vnlock = &vp->v_lock;
-	free(xp, M_NULLFSNODE);
 	vp->v_op = &dead_vnodeops;
-	(void) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
+	VI_UNLOCK(vp);
 	vgone(vp);
 	vput(vp);
+	free(xp, M_NULLFSNODE);
+}
+
+static void
+null_insmntque_dtr(struct vnode *vp, void *xp)
+{
+
+	vput(((struct null_node *)xp)->null_lowervp);
+	null_destroy_proto(vp, xp);
 }
 
 /*
@@ -247,9 +256,7 @@ null_nodeget(mp, lowervp, vpp)
 	*vpp = null_hashins(mp, xp);
 	if (*vpp != NULL) {
 		vrele(lowervp);
-		vp->v_vnlock = &vp->v_lock;
-		xp->null_lowervp = NULL;
-		vrele(vp);
+		null_destroy_proto(vp, xp);
 		return (0);
 	}
 	*vpp = vp;