diff -urp RH_2_6_9_42_0_3.orig/fs/dcache.c RH_2_6_9_42_0_3/fs/dcache.c
--- RH_2_6_9_42_0_3.orig/fs/dcache.c
+++ RH_2_6_9_42_0_3/fs/dcache.c
@@ -229,7 +229,14 @@ int d_invalidate(struct dentry * dentry)
 		spin_unlock(&dcache_lock);
 		return 0;
 	}
-	/*
+
+        /* network invalidation by Lustre */
+	if (dentry->d_flags & DCACHE_LUSTRE_INVALID) {
+		spin_unlock(&dcache_lock);
+		return 0;
+	}
+
+        /*
 	 * Check whether to do a partial shrink_dcache
 	 * to get rid of unused child entries.
 	 */
@@ -1187,19 +1194,28 @@ void d_delete(struct dentry * dentry)
  * Adds a dentry to the hash according to its name.
  */
  
-void d_rehash(struct dentry * entry)
+void d_rehash_cond(struct dentry * entry, int lock)
 {
 	struct hlist_head *list = d_hash(entry->d_parent, entry->d_name.hash);
 
-	spin_lock(&dcache_lock);
+	if (lock)
+		spin_lock(&dcache_lock);
 	spin_lock(&entry->d_lock);
  	entry->d_flags &= ~DCACHE_UNHASHED;
 	spin_unlock(&entry->d_lock);
 	entry->d_bucket = list;
  	hlist_add_head_rcu(&entry->d_hash, list);
-	spin_unlock(&dcache_lock);
+	if (lock)
+		spin_unlock(&dcache_lock);
 }
 
+EXPORT_SYMBOL(d_rehash_cond);
+
+void d_rehash(struct dentry * entry)
+{
+	d_rehash_cond(entry, 1);
+}
+
 #define do_switch(x,y) do { \
 	__typeof__ (x) __tmp = x; \
 	x = y; y = __tmp; } while (0)
diff -urp RH_2_6_9_42_0_3.orig/include/linux/dcache.h RH_2_6_9_42_0_3/include/linux/dcache.h
--- RH_2_6_9_42_0_3.orig/include/linux/dcache.h
+++ RH_2_6_9_42_0_3/include/linux/dcache.h
@@ -157,6 +157,8 @@ d_iput:		no		no		no       yes
 
 #define DCACHE_REFERENCED	0x0008  /* Recently used, don't discard. */
 #define DCACHE_UNHASHED		0x0010	
+#define DCACHE_LUSTRE_INVALID     0x0020  /* Lustre invalidated */
+
 
 extern spinlock_t dcache_lock;