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