Index: linux-2.6/fs/dcache.c
===================================================================
--- linux-2.6.orig/fs/dcache.c	2006-08-31 11:59:09.000000000 +0800
+++ linux-2.6/fs/dcache.c	2006-09-06 14:01:37.000000000 +0800
@@ -226,6 +226,13 @@ 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.
@@ -1242,17 +1249,26 @@ static void __d_rehash(struct dentry * e
  * 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);
 	__d_rehash(entry, list);
 	spin_unlock(&entry->d_lock);
-	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)
Index: linux-2.6/include/linux/dcache.h
===================================================================
--- linux-2.6.orig/include/linux/dcache.h	2006-08-31 12:00:23.000000000 +0800
+++ linux-2.6/include/linux/dcache.h	2006-09-06 14:02:36.000000000 +0800
@@ -176,6 +176,7 @@ d_iput:		no		no		no       yes
 
 #define DCACHE_REFERENCED	0x0008  /* Recently used, don't discard. */
 #define DCACHE_UNHASHED		0x0010	
+#define DCACHE_LUSTRE_INVALID	0x0040  /* Lustre invalidated */
 
 #define DCACHE_INOTIFY_PARENT_WATCHED	0x0020 /* Parent inode is watched */
 
@@ -254,6 +255,7 @@ extern int have_submounts(struct dentry 
  * This adds the entry to the hash queues.
  */
 extern void d_rehash(struct dentry *);
+extern void d_rehash_cond(struct dentry *, int lock);
 
 /**
  * d_add - add dentry to hash queues