--- a/usr/src/uts/common/fs/zfs/zfs_acl.c	Mon Mar 02 11:23:31 2009 -0500
+++ b/usr/src/uts/common/fs/zfs/zfs_acl.c	Mon Mar 02 09:47:43 2009 -0700
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -65,15 +65,16 @@
     ACE_WRITE_ATTRIBUTES|ACE_WRITE_NAMED_ATTRS)
 #define	OWNER_ALLOW_MASK (ACE_WRITE_ACL | ACE_WRITE_OWNER | \
     ACE_WRITE_ATTRIBUTES|ACE_WRITE_NAMED_ATTRS)
-#define	WRITE_MASK_DATA (ACE_WRITE_DATA|ACE_APPEND_DATA|ACE_WRITE_NAMED_ATTRS)
 
 #define	ZFS_CHECKED_MASKS (ACE_READ_ACL|ACE_READ_ATTRIBUTES|ACE_READ_DATA| \
     ACE_READ_NAMED_ATTRS|ACE_WRITE_DATA|ACE_WRITE_ATTRIBUTES| \
     ACE_WRITE_NAMED_ATTRS|ACE_APPEND_DATA|ACE_EXECUTE|ACE_WRITE_OWNER| \
     ACE_WRITE_ACL|ACE_DELETE|ACE_DELETE_CHILD|ACE_SYNCHRONIZE)
 
-#define	WRITE_MASK (WRITE_MASK_DATA|ACE_WRITE_ATTRIBUTES|ACE_WRITE_ACL|\
-    ACE_WRITE_OWNER|ACE_DELETE|ACE_DELETE_CHILD)
+#define	WRITE_MASK_DATA (ACE_WRITE_DATA|ACE_APPEND_DATA|ACE_WRITE_NAMED_ATTRS)
+#define	WRITE_MASK_ATTRS (ACE_WRITE_ACL|ACE_WRITE_OWNER|ACE_WRITE_ATTRIBUTES| \
+    ACE_DELETE|ACE_DELETE_CHILD)
+#define	WRITE_MASK (WRITE_MASK_DATA|WRITE_MASK_ATTRS)
 
 #define	OGE_CLEAR	(ACE_READ_DATA|ACE_LIST_DIRECTORY|ACE_WRITE_DATA| \
     ACE_ADD_FILE|ACE_APPEND_DATA|ACE_ADD_SUBDIRECTORY|ACE_EXECUTE)
@@ -2217,7 +2218,8 @@
 
 	if ((v4_mode & WRITE_MASK) &&
 	    (zp->z_zfsvfs->z_vfs->vfs_flag & VFS_RDONLY) &&
-	    (!IS_DEVVP(ZTOV(zp)))) {
+	    (!IS_DEVVP(ZTOV(zp)) ||
+	    (IS_DEVVP(ZTOV(zp)) && (v4_mode & WRITE_MASK_ATTRS)))) {
 		*check_privs = B_FALSE;
 		return (EROFS);
 	}