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Michael Halcrow237fead2006-10-04 02:16:22 -07001/**
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 * Michael C. Thompson <mcthomps@us.ibm.com>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation; either version 2 of the
13 * License, or (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
23 * 02111-1307, USA.
24 */
25
26#include <linux/fs.h>
27#include <linux/mount.h>
28#include <linux/key.h>
29#include <linux/seq_file.h>
30#include <linux/crypto.h>
31#include "ecryptfs_kernel.h"
32
33struct kmem_cache *ecryptfs_inode_info_cache;
34
35/**
36 * ecryptfs_alloc_inode - allocate an ecryptfs inode
37 * @sb: Pointer to the ecryptfs super block
38 *
39 * Called to bring an inode into existence.
40 *
41 * Only handle allocation, setting up structures should be done in
42 * ecryptfs_read_inode. This is because the kernel, between now and
43 * then, will 0 out the private data pointer.
44 *
45 * Returns a pointer to a newly allocated inode, NULL otherwise
46 */
47static struct inode *ecryptfs_alloc_inode(struct super_block *sb)
48{
49 struct ecryptfs_inode_info *ecryptfs_inode;
50 struct inode *inode = NULL;
51
52 ecryptfs_inode = kmem_cache_alloc(ecryptfs_inode_info_cache,
Christoph Lametere94b1762006-12-06 20:33:17 -080053 GFP_KERNEL);
Michael Halcrow237fead2006-10-04 02:16:22 -070054 if (unlikely(!ecryptfs_inode))
55 goto out;
56 ecryptfs_init_crypt_stat(&ecryptfs_inode->crypt_stat);
57 inode = &ecryptfs_inode->vfs_inode;
58out:
59 return inode;
60}
61
62/**
63 * ecryptfs_destroy_inode
64 * @inode: The ecryptfs inode
65 *
66 * This is used during the final destruction of the inode.
67 * All allocation of memory related to the inode, including allocated
68 * memory in the crypt_stat struct, will be released here.
69 * There should be no chance that this deallocation will be missed.
70 */
71static void ecryptfs_destroy_inode(struct inode *inode)
72{
73 struct ecryptfs_inode_info *inode_info;
74
75 inode_info = ecryptfs_inode_to_private(inode);
76 ecryptfs_destruct_crypt_stat(&inode_info->crypt_stat);
77 kmem_cache_free(ecryptfs_inode_info_cache, inode_info);
78}
79
80/**
81 * ecryptfs_init_inode
82 * @inode: The ecryptfs inode
83 *
84 * Set up the ecryptfs inode.
85 */
86void ecryptfs_init_inode(struct inode *inode, struct inode *lower_inode)
87{
88 ecryptfs_set_inode_lower(inode, lower_inode);
89 inode->i_ino = lower_inode->i_ino;
90 inode->i_version++;
91 inode->i_op = &ecryptfs_main_iops;
92 inode->i_fop = &ecryptfs_main_fops;
93 inode->i_mapping->a_ops = &ecryptfs_aops;
94}
95
96/**
97 * ecryptfs_put_super
98 * @sb: Pointer to the ecryptfs super block
99 *
100 * Final actions when unmounting a file system.
101 * This will handle deallocation and release of our private data.
102 */
103static void ecryptfs_put_super(struct super_block *sb)
104{
105 struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
106
107 ecryptfs_destruct_mount_crypt_stat(&sb_info->mount_crypt_stat);
108 kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
109 ecryptfs_set_superblock_private(sb, NULL);
110}
111
112/**
113 * ecryptfs_statfs
114 * @sb: The ecryptfs super block
115 * @buf: The struct kstatfs to fill in with stats
116 *
117 * Get the filesystem statistics. Currently, we let this pass right through
118 * to the lower filesystem and take no action ourselves.
119 */
120static int ecryptfs_statfs(struct dentry *dentry, struct kstatfs *buf)
121{
122 return vfs_statfs(ecryptfs_dentry_to_lower(dentry), buf);
123}
124
125/**
126 * ecryptfs_clear_inode
127 * @inode - The ecryptfs inode
128 *
129 * Called by iput() when the inode reference count reached zero
130 * and the inode is not hashed anywhere. Used to clear anything
131 * that needs to be, before the inode is completely destroyed and put
132 * on the inode free list. We use this to drop out reference to the
133 * lower inode.
134 */
135static void ecryptfs_clear_inode(struct inode *inode)
136{
137 iput(ecryptfs_inode_to_lower(inode));
138}
139
140/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700141 * ecryptfs_show_options
142 *
143 * Prints the directory we are currently mounted over.
144 * Returns zero on success; non-zero otherwise
145 */
146static int ecryptfs_show_options(struct seq_file *m, struct vfsmount *mnt)
147{
148 struct super_block *sb = mnt->mnt_sb;
149 struct dentry *lower_root_dentry = ecryptfs_dentry_to_lower(sb->s_root);
150 struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(sb->s_root);
151 char *tmp_page;
152 char *path;
153 int rc = 0;
154
155 tmp_page = (char *)__get_free_page(GFP_KERNEL);
156 if (!tmp_page) {
157 rc = -ENOMEM;
158 goto out;
159 }
160 path = d_path(lower_root_dentry, lower_mnt, tmp_page, PAGE_SIZE);
161 if (IS_ERR(path)) {
162 rc = PTR_ERR(path);
163 goto out;
164 }
165 seq_printf(m, ",dir=%s", path);
166 free_page((unsigned long)tmp_page);
167out:
168 return rc;
169}
170
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -0800171const struct super_operations ecryptfs_sops = {
Michael Halcrow237fead2006-10-04 02:16:22 -0700172 .alloc_inode = ecryptfs_alloc_inode,
173 .destroy_inode = ecryptfs_destroy_inode,
174 .drop_inode = generic_delete_inode,
175 .put_super = ecryptfs_put_super,
176 .statfs = ecryptfs_statfs,
177 .remount_fs = NULL,
178 .clear_inode = ecryptfs_clear_inode,
Michael Halcrow237fead2006-10-04 02:16:22 -0700179 .show_options = ecryptfs_show_options
180};