fs/ecryptfs/dentry.c

   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 "ecryptfs_kernel.h"
  28
  29 /**
  30  * ecryptfs_d_revalidate - revalidate an ecryptfs dentry
  31  * @dentry: The ecryptfs dentry
  32  * @nd: The associated nameidata
  33  *
  34  * Called when the VFS needs to revalidate a dentry. This
  35  * is called whenever a name lookup finds a dentry in the
  36  * dcache. Most filesystems leave this as NULL, because all their
  37  * dentries in the dcache are valid.
  38  *
  39  * Returns 1 if valid, 0 otherwise.
  40  *
  41  */
  42 static int ecryptfs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
  43 {
  44         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
  45         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
  46         struct dentry *dentry_save;
  47         struct vfsmount *vfsmount_save;
  48         int rc = 1;
  49
  50         if (!lower_dentry->d_op || !lower_dentry->d_op->d_revalidate)
  51                 goto out;
  52         dentry_save = nd->dentry;
  53         vfsmount_save = nd->mnt;
  54         nd->dentry = lower_dentry;
  55         nd->mnt = lower_mnt;
  56         rc = lower_dentry->d_op->d_revalidate(lower_dentry, nd);
  57         nd->dentry = dentry_save;
  58         nd->mnt = vfsmount_save;
  59 out:
  60         return rc;
  61 }
  62
  63 struct kmem_cache *ecryptfs_dentry_info_cache;
  64
  65 /**
  66  * ecryptfs_d_release
  67  * @dentry: The ecryptfs dentry
  68  *
  69  * Called when a dentry is really deallocated.
  70  */
  71 static void ecryptfs_d_release(struct dentry *dentry)
  72 {
  73         struct dentry *lower_dentry;
  74
  75         lower_dentry = ecryptfs_dentry_to_lower(dentry);
  76         if (ecryptfs_dentry_to_private(dentry))
  77                 kmem_cache_free(ecryptfs_dentry_info_cache,
  78                                 ecryptfs_dentry_to_private(dentry));
  79         if (lower_dentry)
  80                 dput(lower_dentry);
  81         return;
  82 }
  83
  84 struct dentry_operations ecryptfs_dops = {
  85         .d_revalidate = ecryptfs_d_revalidate,
  86         .d_release = ecryptfs_d_release,
  87 };