diff -Nurb linux-2.6.22-20/fs/inode.c linux-2.6.22-40/fs/inode.c
--- linux-2.6.22-20/fs/inode.c	2007-07-08 19:32:17.000000000 -0400
+++ linux-2.6.22-40/fs/inode.c	2008-04-03 16:41:53.000000000 -0400
@@ -122,6 +122,7 @@
 		inode->i_fop = &empty_fops;
 		inode->i_nlink = 1;
 		atomic_set(&inode->i_writecount, 0);
+		mutex_init(&inode->i_mutex);
 		inode->i_size = 0;
 		inode->i_blocks = 0;
 		inode->i_bytes = 0;
@@ -1102,6 +1103,7 @@
 
 	if (op && op->drop_inode)
 		drop = op->drop_inode;
+	BUG_ON(atomic_read(&inode->i_mutex.count)!=1);
 	drop(inode);
 }