/**
   * eCryptfs: Linux filesystem encryption layer
   *
   * Copyright (C) 1997-2003 Erez Zadok
   * Copyright (C) 2001-2003 Stony Brook University
   * Copyright (C) 2004-2006 International Business Machines Corp.
   *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License as
   * published by the Free Software Foundation; either version 2 of the
   * License, or (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
   * 02111-1307, USA.
   */
  
  #include <linux/dcache.h>
  #include <linux/namei.h>
  #include <linux/mount.h>
  #include <linux/fs_stack.h>
  #include <linux/slab.h>
  #include "ecryptfs_kernel.h"
  
  /**
   * ecryptfs_d_revalidate - revalidate an ecryptfs dentry
   * @dentry: The ecryptfs dentry
   * @flags: lookup flags
   *
   * Called when the VFS needs to revalidate a dentry. This
   * is called whenever a name lookup finds a dentry in the
   * dcache. Most filesystems leave this as NULL, because all their
   * dentries in the dcache are valid.
   *
   * Returns 1 if valid, 0 otherwise.
   *
   */
  static int ecryptfs_d_revalidate(struct dentry *dentry, unsigned int flags)
  {
  	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
  	int rc;
  
  	if (!(lower_dentry->d_flags & DCACHE_OP_REVALIDATE))
  		return 1;
  
  	if (flags & LOOKUP_RCU)
  		return -ECHILD;
  
  	rc = lower_dentry->d_op->d_revalidate(lower_dentry, flags);
  	if (dentry->d_inode) {
  		struct inode *lower_inode =
  			ecryptfs_inode_to_lower(dentry->d_inode);
  
  		fsstack_copy_attr_all(dentry->d_inode, lower_inode);
  	}
  	return rc;
  }
  
  struct kmem_cache *ecryptfs_dentry_info_cache;
  
  static void ecryptfs_dentry_free_rcu(struct rcu_head *head)
  {
  	kmem_cache_free(ecryptfs_dentry_info_cache,
  		container_of(head, struct ecryptfs_dentry_info, rcu));
  }
  
  /**
   * ecryptfs_d_release
   * @dentry: The ecryptfs dentry
   *
   * Called when a dentry is really deallocated.
   */
  static void ecryptfs_d_release(struct dentry *dentry)
  {
  	struct ecryptfs_dentry_info *p = dentry->d_fsdata;
  	if (p) {
  		path_put(&p->lower_path);
  		call_rcu(&p->rcu, ecryptfs_dentry_free_rcu);
  	}
  }
  
  const struct dentry_operations ecryptfs_dops = {
  	.d_revalidate = ecryptfs_d_revalidate,
  	.d_release = ecryptfs_d_release,
  };