LXR linux/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 <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 = ecryptfs_dentry_to_lower(dentry);
  48        int rc = 1;
  49
  50        if (flags & LOOKUP_RCU)
  51                return -ECHILD;
  52
  53        if (lower_dentry->d_flags & DCACHE_OP_REVALIDATE)
  54                rc = lower_dentry->d_op->d_revalidate(lower_dentry, flags);
  55
  56        if (d_really_is_positive(dentry)) {
  57                struct inode *inode = d_inode(dentry);
  58
  59                fsstack_copy_attr_all(inode, ecryptfs_inode_to_lower(inode));
  60                if (!inode->i_nlink)
  61                        return 0;
  62        }
  63        return rc;
  64}
  65
  66struct kmem_cache *ecryptfs_dentry_info_cache;
  67
  68static void ecryptfs_dentry_free_rcu(struct rcu_head *head)
  69{
  70        kmem_cache_free(ecryptfs_dentry_info_cache,
  71                container_of(head, struct ecryptfs_dentry_info, rcu));
  72}
  73
  74/**
  75 * ecryptfs_d_release
  76 * @dentry: The ecryptfs dentry
  77 *
  78 * Called when a dentry is really deallocated.
  79 */
  80static void ecryptfs_d_release(struct dentry *dentry)
  81{
  82        struct ecryptfs_dentry_info *p = dentry->d_fsdata;
  83        if (p) {
  84                path_put(&p->lower_path);
  85                call_rcu(&p->rcu, ecryptfs_dentry_free_rcu);
  86        }
  87}
  88
  89const struct dentry_operations ecryptfs_dops = {
  90        .d_revalidate = ecryptfs_d_revalidate,
  91        .d_release = ecryptfs_d_release,
  92};
  93