Introduce lock-free versions of d_rehash and d_move.

 fs/dcache.c            |   22 ++++++++++++++++++----
 include/linux/dcache.h |    2 ++
 2 files changed, 20 insertions(+), 4 deletions(-)

Index: linux-2.6.10/fs/dcache.c
===================================================================
--- linux-2.6.10.orig/fs/dcache.c	2005-03-31 15:35:26.000000000 +0800
+++ linux-2.6.10/fs/dcache.c	2005-03-31 19:16:50.807244880 +0800
@@ -1116,29 +1116,23 @@
 	spin_unlock(&dcache_lock);
 }
 
-static void __d_rehash(struct dentry * entry, struct hlist_head *list)
+void __d_rehash(struct dentry * entry)
 {
-
- 	entry->d_flags &= ~DCACHE_UNHASHED;
- 	hlist_add_head_rcu(&entry->d_hash, list);
+  	struct hlist_head *list = d_hash(entry->d_parent, entry->d_name.hash);
+  
+  	spin_lock(&entry->d_lock);
+   	entry->d_flags &= ~DCACHE_UNHASHED;
+   	hlist_add_head_rcu(&entry->d_hash, list);
+  	spin_unlock(&entry->d_lock);
 }
-
-/**
- * d_rehash	- add an entry back to the hash
- * @entry: dentry to add to the hash
- *
- * Adds a dentry to the hash according to its name.
- */
  
+EXPORT_SYMBOL(__d_rehash);
+  
 void d_rehash(struct dentry * entry)
 {
-	struct hlist_head *list = d_hash(entry->d_parent, entry->d_name.hash);
-
-	spin_lock(&dcache_lock);
-	spin_lock(&entry->d_lock);
-	__d_rehash(entry, list);
-	spin_unlock(&entry->d_lock);
-	spin_unlock(&dcache_lock);
+ 	spin_lock(&dcache_lock);
+ 	__d_rehash(entry);
+  	spin_unlock(&dcache_lock);
 }
 
 #define do_switch(x,y) do { \
@@ -1213,14 +1207,13 @@
  * dcache entries should not be moved in this way.
  */
 
-void d_move(struct dentry * dentry, struct dentry * target)
+void __d_move(struct dentry * dentry, struct dentry * target)
 {
 	struct hlist_head *list;
 
 	if (!dentry->d_inode)
 		printk(KERN_WARNING "VFS: moving negative dcache entry\n");
 
-	spin_lock(&dcache_lock);
 	write_seqlock(&rename_lock);
 	/*
 	 * XXXX: do we really need to take target->d_lock?
@@ -1241,7 +1234,8 @@
 
 already_unhashed:
 	list = d_hash(target->d_parent, target->d_name.hash);
-	__d_rehash(dentry, list);
+   	dentry->d_flags &= ~DCACHE_UNHASHED;
+   	hlist_add_head_rcu(&dentry->d_hash, list);
 
 	/* Unhash the target: dput() will then get rid of it */
 	__d_drop(target);
@@ -1280,6 +1274,14 @@
 	spin_unlock(&target->d_lock);
 	spin_unlock(&dentry->d_lock);
 	write_sequnlock(&rename_lock);
+}
+
+EXPORT_SYMBOL(__d_move);
+
+void d_move(struct dentry *dentry, struct dentry *target)
+{
+	spin_lock(&dcache_lock);
+	__d_move(dentry, target);
 	spin_unlock(&dcache_lock);
 }
 
Index: linux-2.6.10/include/linux/dcache.h
===================================================================
--- linux-2.6.10.orig/include/linux/dcache.h	2005-03-31 15:35:26.000000000 +0800
+++ linux-2.6.10/include/linux/dcache.h	2005-03-31 19:15:49.684536944 +0800
@@ -228,6 +228,7 @@
  * This adds the entry to the hash queues.
  */
 extern void d_rehash(struct dentry *);
+extern void __d_rehash(struct dentry *);
 
 /**
  * d_add - add dentry to hash queues
@@ -246,6 +247,7 @@
 
 /* used for rename() and baskets */
 extern void d_move(struct dentry *, struct dentry *);
+extern void __d_move(struct dentry *, struct dentry *);
 
 /* appendix may either be NULL or be used for transname suffixes */
 extern struct dentry * d_lookup(struct dentry *, struct qstr *);