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 * @nd: The associated nameidata
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 */
ecryptfs_d_revalidate(struct dentry * dentry,struct nameidata * nd)45 static int ecryptfs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
46 {
47 struct dentry *lower_dentry;
48 struct vfsmount *lower_mnt;
49 struct dentry *dentry_save = NULL;
50 struct vfsmount *vfsmount_save = NULL;
51 int rc = 1;
52
53 if (nd && nd->flags & LOOKUP_RCU)
54 return -ECHILD;
55
56 lower_dentry = ecryptfs_dentry_to_lower(dentry);
57 lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
58 if (!lower_dentry->d_op || !lower_dentry->d_op->d_revalidate)
59 goto out;
60 if (nd) {
61 dentry_save = nd->path.dentry;
62 vfsmount_save = nd->path.mnt;
63 nd->path.dentry = lower_dentry;
64 nd->path.mnt = lower_mnt;
65 }
66 rc = lower_dentry->d_op->d_revalidate(lower_dentry, nd);
67 if (nd) {
68 nd->path.dentry = dentry_save;
69 nd->path.mnt = vfsmount_save;
70 }
71 if (dentry->d_inode) {
72 struct inode *lower_inode =
73 ecryptfs_inode_to_lower(dentry->d_inode);
74
75 fsstack_copy_attr_all(dentry->d_inode, lower_inode);
76 }
77 out:
78 return rc;
79 }
80
81 struct kmem_cache *ecryptfs_dentry_info_cache;
82
83 /**
84 * ecryptfs_d_release
85 * @dentry: The ecryptfs dentry
86 *
87 * Called when a dentry is really deallocated.
88 */
ecryptfs_d_release(struct dentry * dentry)89 static void ecryptfs_d_release(struct dentry *dentry)
90 {
91 if (ecryptfs_dentry_to_private(dentry)) {
92 if (ecryptfs_dentry_to_lower(dentry)) {
93 dput(ecryptfs_dentry_to_lower(dentry));
94 mntput(ecryptfs_dentry_to_lower_mnt(dentry));
95 }
96 kmem_cache_free(ecryptfs_dentry_info_cache,
97 ecryptfs_dentry_to_private(dentry));
98 }
99 return;
100 }
101
102 const struct dentry_operations ecryptfs_dops = {
103 .d_revalidate = ecryptfs_d_revalidate,
104 .d_release = ecryptfs_d_release,
105 };
106