[patch] lockdep: annotate vfs_rmdir for filesystems that take i_mutex in delete_inode

[Arjan van de Ven <arjan@linux.intel.com>]

> The VFS takes the directory i_mutex and reiserfs_delete_inode() takes the
> to-be-deleted file's i_mutex.
> 
> That's notabug and lockdep will need to be taught about it.

Actually the annotation is in vfs_rmdir() since that is where the parent
is taken (this may sound odd but the I_MUTEX_* ordering rules require
the parent taking to be annotated rather than the child)

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>

Index: linux-2.6.18-rc2-git5/fs/namei.c
===================================================================
--- linux-2.6.18-rc2-git5.orig/fs/namei.c
+++ linux-2.6.18-rc2-git5/fs/namei.c
@@ -1967,7 +1967,7 @@ int vfs_rmdir(struct inode *dir, struct 
 
 	DQUOT_INIT(dir);
 
-	mutex_lock(&dentry->d_inode->i_mutex);
+	mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_PARENT);
 	dentry_unhash(dentry);
 	if (d_mountpoint(dentry))
 		error = -EBUSY;