[PATCH vfs-2.6 3/6] vfs: add __d_instantiate() helper

This adds __d_instantiate() for users which is already taking
dcache_lock, and replace with it.

The part of d_add_ci() isn't equivalent. But it should be needed
fsnotify_d_instantiate() actually, because the path is to add the
inode to negative dentry.  fsnotify_d_instantiate() should be called
after change from negative to positive.
Signed-off-by: NOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

fs/dcache.c

@@ -981,6 +981,15 @@ struct dentry *d_alloc_name(struct dentry *parent, const char *name)
 	return d_alloc(parent, &q);
 }
 
+/* the caller must hold dcache_lock */
+static void __d_instantiate(struct dentry *dentry, struct inode *inode)
+{
+	if (inode)
+		list_add(&dentry->d_alias, &inode->i_dentry);
+	dentry->d_inode = inode;
+	fsnotify_d_instantiate(dentry, inode);
+}
+
 /**
  * d_instantiate - fill in inode information for a dentry
  * @entry: dentry to complete
@@ -1000,10 +1009,7 @@ void d_instantiate(struct dentry *entry, struct inode * inode)
 {
 	BUG_ON(!list_empty(&entry->d_alias));
 	spin_lock(&dcache_lock);
-	if (inode)
-		list_add(&entry->d_alias, &inode->i_dentry);
-	entry->d_inode = inode;
-	fsnotify_d_instantiate(entry, inode);
+	__d_instantiate(entry, inode);
 	spin_unlock(&dcache_lock);
 	security_d_instantiate(entry, inode);
 }
@@ -1033,7 +1039,7 @@ static struct dentry *__d_instantiate_unique(struct dentry *entry,
 	unsigned int hash = entry->d_name.hash;
 
 	if (!inode) {
-		entry->d_inode = NULL;
+		__d_instantiate(entry, NULL);
 		return NULL;
 	}
 
@@ -1052,9 +1058,7 @@ static struct dentry *__d_instantiate_unique(struct dentry *entry,
 		return alias;
 	}
 
-	list_add(&entry->d_alias, &inode->i_dentry);
-	entry->d_inode = inode;
-	fsnotify_d_instantiate(entry, inode);
+	__d_instantiate(entry, inode);
 	return NULL;
 }
 
@@ -1213,10 +1217,8 @@ struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry)
 			d_move(new, dentry);
 			iput(inode);
 		} else {
-			/* d_instantiate takes dcache_lock, so we do it by hand */
-			list_add(&dentry->d_alias, &inode->i_dentry);
-			dentry->d_inode = inode;
-			fsnotify_d_instantiate(dentry, inode);
+			/* already taking dcache_lock, so d_add() by hand */
+			__d_instantiate(dentry, inode);
 			spin_unlock(&dcache_lock);
 			security_d_instantiate(dentry, inode);
 			d_rehash(dentry);
@@ -1299,8 +1301,7 @@ struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode,
 		 * d_instantiate() by hand because it takes dcache_lock which
 		 * we already hold.
 		 */
-		list_add(&found->d_alias, &inode->i_dentry);
-		found->d_inode = inode;
+		__d_instantiate(found, inode);
 		spin_unlock(&dcache_lock);
 		security_d_instantiate(found, inode);
 		return found;
@@ -1833,7 +1834,7 @@ struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode)
 
 	if (!inode) {
 		actual = dentry;
-		dentry->d_inode = NULL;
+		__d_instantiate(dentry, NULL);
 		goto found_lock;
 	}