svn commit: r208773 - head/sys/kern

[Konstantin Belousov]

Author: kib
Date: Thu Jun  3 10:20:08 2010
New Revision: 208773
URL: http://svn.freebsd.org/changeset/base/208773

Log:
  Sometimes vnodes share the lock despite being different vnodes on
  different mount points, e.g. the nullfs vnode and the covered vnode
  from the lower filesystem. In this case, existing assertion in
  vop_rename_pre() may be triggered.
  
  Check for vnode locks equiality instead of the vnodes itself to
  not trip over the situation.
  
  Submitted by:	Mikolaj Golub <to.my.trociny at gmail.com>
  Tested by:	pho
  MFC after:	2 weeks

Modified:
  head/sys/kern/vfs_subr.c

Modified: head/sys/kern/vfs_subr.c
==============================================================================
--- head/sys/kern/vfs_subr.c	Thu Jun  3 10:11:45 2010	(r208772)
+++ head/sys/kern/vfs_subr.c	Thu Jun  3 10:20:08 2010	(r208773)
@@ -3793,9 +3793,10 @@ vop_rename_pre(void *ap)
 	ASSERT_VI_UNLOCKED(a->a_fdvp, "VOP_RENAME");
 
 	/* Check the source (from). */
-	if (a->a_tdvp != a->a_fdvp && a->a_tvp != a->a_fdvp)
+	if (a->a_tdvp->v_vnlock != a->a_fdvp->v_vnlock &&
+	    (a->a_tvp == NULL || a->a_tvp->v_vnlock != a->a_fdvp->v_vnlock))
 		ASSERT_VOP_UNLOCKED(a->a_fdvp, "vop_rename: fdvp locked");
-	if (a->a_tvp != a->a_fvp)
+	if (a->a_tvp == NULL || a->a_tvp->v_vnlock != a->a_fvp->v_vnlock)
 		ASSERT_VOP_UNLOCKED(a->a_fvp, "vop_rename: fvp locked");
 
 	/* Check the target. */