linux/fs/ecryptfs/dentry.c
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   1/**
   2 * eCryptfs: Linux filesystem encryption layer
   3 *
   4 * Copyright (C) 1997-2003 Erez Zadok
   5 * Copyright (C) 2001-2003 Stony Brook University
   6 * Copyright (C) 2004-2006 International Business Machines Corp.
   7 *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
   8 *
   9 * This program is free software; you can redistribute it and/or
  10 * modify it under the terms of the GNU General Public License as
  11 * published by the Free Software Foundation; either version 2 of the
  12 * License, or (at your option) any later version.
  13 *
  14 * This program is distributed in the hope that it will be useful, but
  15 * WITHOUT ANY WARRANTY; without even the implied warranty of
  16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17 * General Public License for more details.
  18 *
  19 * You should have received a copy of the GNU General Public License
  20 * along with this program; if not, write to the Free Software
  21 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  22 * 02111-1307, USA.
  23 */
  24
  25#include <linux/dcache.h>
  26#include <linux/namei.h>
  27#include <linux/mount.h>
  28#include <linux/fs_stack.h>
  29#include <linux/slab.h>
  30#include "ecryptfs_kernel.h"
  31
  32/**
  33 * ecryptfs_d_revalidate - revalidate an ecryptfs dentry
  34 * @dentry: The ecryptfs dentry
  35 * @flags: lookup flags
  36 *
  37 * Called when the VFS needs to revalidate a dentry. This
  38 * is called whenever a name lookup finds a dentry in the
  39 * dcache. Most filesystems leave this as NULL, because all their
  40 * dentries in the dcache are valid.
  41 *
  42 * Returns 1 if valid, 0 otherwise.
  43 *
  44 */
  45static int ecryptfs_d_revalidate(struct dentry *dentry, unsigned int flags)
  46{
  47        struct dentry *lower_dentry;
  48        struct vfsmount *lower_mnt;
  49        int rc = 1;
  50
  51        if (flags & LOOKUP_RCU)
  52                return -ECHILD;
  53
  54        lower_dentry = ecryptfs_dentry_to_lower(dentry);
  55        lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
  56        if (!lower_dentry->d_op || !lower_dentry->d_op->d_revalidate)
  57                goto out;
  58        rc = lower_dentry->d_op->d_revalidate(lower_dentry, flags);
  59        if (dentry->d_inode) {
  60                struct inode *lower_inode =
  61                        ecryptfs_inode_to_lower(dentry->d_inode);
  62
  63                fsstack_copy_attr_all(dentry->d_inode, lower_inode);
  64        }
  65out:
  66        return rc;
  67}
  68
  69struct kmem_cache *ecryptfs_dentry_info_cache;
  70
  71/**
  72 * ecryptfs_d_release
  73 * @dentry: The ecryptfs dentry
  74 *
  75 * Called when a dentry is really deallocated.
  76 */
  77static void ecryptfs_d_release(struct dentry *dentry)
  78{
  79        if (ecryptfs_dentry_to_private(dentry)) {
  80                if (ecryptfs_dentry_to_lower(dentry)) {
  81                        dput(ecryptfs_dentry_to_lower(dentry));
  82                        mntput(ecryptfs_dentry_to_lower_mnt(dentry));
  83                }
  84                kmem_cache_free(ecryptfs_dentry_info_cache,
  85                                ecryptfs_dentry_to_private(dentry));
  86        }
  87        return;
  88}
  89
  90const struct dentry_operations ecryptfs_dops = {
  91        .d_revalidate = ecryptfs_d_revalidate,
  92        .d_release = ecryptfs_d_release,
  93};
  94
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