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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                 :            :  */
      45                 :          0 : static int ecryptfs_d_revalidate(struct dentry *dentry, unsigned int flags)
      46                 :            : {
      47                 :            :         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
      48                 :            :         int rc;
      49                 :            : 
      50         [ #  # ]:          0 :         if (!(lower_dentry->d_flags & DCACHE_OP_REVALIDATE))
      51                 :            :                 return 1;
      52                 :            : 
      53         [ #  # ]:          0 :         if (flags & LOOKUP_RCU)
      54                 :            :                 return -ECHILD;
      55                 :            : 
      56                 :          0 :         rc = lower_dentry->d_op->d_revalidate(lower_dentry, flags);
      57         [ #  # ]:          0 :         if (dentry->d_inode) {
      58                 :            :                 struct inode *lower_inode =
      59                 :            :                         ecryptfs_inode_to_lower(dentry->d_inode);
      60                 :            : 
      61                 :          0 :                 fsstack_copy_attr_all(dentry->d_inode, lower_inode);
      62                 :            :         }
      63                 :          0 :         return rc;
      64                 :            : }
      65                 :            : 
      66                 :            : struct kmem_cache *ecryptfs_dentry_info_cache;
      67                 :            : 
      68                 :          0 : static void ecryptfs_dentry_free_rcu(struct rcu_head *head)
      69                 :            : {
      70                 :          0 :         kmem_cache_free(ecryptfs_dentry_info_cache,
      71                 :          0 :                 container_of(head, struct ecryptfs_dentry_info, rcu));
      72                 :          0 : }
      73                 :            : 
      74                 :            : /**
      75                 :            :  * ecryptfs_d_release
      76                 :            :  * @dentry: The ecryptfs dentry
      77                 :            :  *
      78                 :            :  * Called when a dentry is really deallocated.
      79                 :            :  */
      80                 :          0 : static void ecryptfs_d_release(struct dentry *dentry)
      81                 :            : {
      82                 :          0 :         struct ecryptfs_dentry_info *p = dentry->d_fsdata;
      83         [ #  # ]:          0 :         if (p) {
      84                 :          0 :                 path_put(&p->lower_path);
      85                 :          0 :                 call_rcu(&p->rcu, ecryptfs_dentry_free_rcu);
      86                 :            :         }
      87                 :          0 : }
      88                 :            : 
      89                 :            : const struct dentry_operations ecryptfs_dops = {
      90                 :            :         .d_revalidate = ecryptfs_d_revalidate,
      91                 :            :         .d_release = ecryptfs_d_release,
      92                 :            : };