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 <linux/mount.h>
  28 #include "ecryptfs_kernel.h"
  29
  30 /**
  31  * ecryptfs_d_revalidate - revalidate an ecryptfs dentry
  32  * @dentry: The ecryptfs dentry
  33  * @nd: The associated nameidata
  34  *
  35  * Called when the VFS needs to revalidate a dentry. This
  36  * is called whenever a name lookup finds a dentry in the
  37  * dcache. Most filesystems leave this as NULL, because all their
  38  * dentries in the dcache are valid.
  39  *
  40  * Returns 1 if valid, 0 otherwise.
  41  *
  42  */
  43 static int ecryptfs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
  44 {
  45         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
  46         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
  47         struct dentry *dentry_save;
  48         struct vfsmount *vfsmount_save;
  49         int rc = 1;
  50
  51         if (!lower_dentry->d_op || !lower_dentry->d_op->d_revalidate)
  52                 goto out;
  53         dentry_save = nd->dentry;
  54         vfsmount_save = nd->mnt;
  55         nd->dentry = lower_dentry;
  56         nd->mnt = lower_mnt;
  57         rc = lower_dentry->d_op->d_revalidate(lower_dentry, nd);
  58         nd->dentry = dentry_save;
  59         nd->mnt = vfsmount_save;
  60         if (dentry->d_inode) {
  61                 struct inode *lower_inode =
  62                         ecryptfs_inode_to_lower(dentry->d_inode);
  63
  64                 ecryptfs_copy_attr_all(dentry->d_inode, lower_inode);
  65         }
  66 out:
  67         return rc;
  68 }
  69
  70 struct kmem_cache *ecryptfs_dentry_info_cache;
  71
  72 /**
  73  * ecryptfs_d_release
  74  * @dentry: The ecryptfs dentry
  75  *
  76  * Called when a dentry is really deallocated.
  77  */
  78 static void ecryptfs_d_release(struct dentry *dentry)
  79 {
  80         struct dentry *lower_dentry;
  81
  82         lower_dentry = ecryptfs_dentry_to_lower(dentry);
  83         if (ecryptfs_dentry_to_private(dentry))
  84                 kmem_cache_free(ecryptfs_dentry_info_cache,
  85                                 ecryptfs_dentry_to_private(dentry));
  86         if (lower_dentry) {
  87                 struct vfsmount *lower_mnt =
  88                         ecryptfs_dentry_to_lower_mnt(dentry);
  89
  90                 mntput(lower_mnt);
  91                 dput(lower_dentry);
  92         }
  93         return;
  94 }
  95
  96 struct dentry_operations ecryptfs_dops = {
  97         .d_revalidate = ecryptfs_d_revalidate,
  98         .d_release = ecryptfs_d_release,
  99 };