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237fead6 MH |
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 | * 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> | |
4981e081 | 30 | #include <linux/file.h> |
237fead6 MH |
31 | #include <linux/crypto.h> |
32 | #include "ecryptfs_kernel.h" | |
33 | ||
34 | struct kmem_cache *ecryptfs_inode_info_cache; | |
35 | ||
36 | /** | |
37 | * ecryptfs_alloc_inode - allocate an ecryptfs inode | |
38 | * @sb: Pointer to the ecryptfs super block | |
39 | * | |
40 | * Called to bring an inode into existence. | |
41 | * | |
42 | * Only handle allocation, setting up structures should be done in | |
43 | * ecryptfs_read_inode. This is because the kernel, between now and | |
44 | * then, will 0 out the private data pointer. | |
45 | * | |
46 | * Returns a pointer to a newly allocated inode, NULL otherwise | |
47 | */ | |
48 | static struct inode *ecryptfs_alloc_inode(struct super_block *sb) | |
49 | { | |
035241d3 | 50 | struct ecryptfs_inode_info *inode_info; |
237fead6 MH |
51 | struct inode *inode = NULL; |
52 | ||
035241d3 MH |
53 | inode_info = kmem_cache_alloc(ecryptfs_inode_info_cache, GFP_KERNEL); |
54 | if (unlikely(!inode_info)) | |
237fead6 | 55 | goto out; |
035241d3 MH |
56 | ecryptfs_init_crypt_stat(&inode_info->crypt_stat); |
57 | mutex_init(&inode_info->lower_file_mutex); | |
58 | inode_info->lower_file = NULL; | |
59 | inode = &inode_info->vfs_inode; | |
237fead6 MH |
60 | out: |
61 | return inode; | |
62 | } | |
63 | ||
64 | /** | |
65 | * ecryptfs_destroy_inode | |
66 | * @inode: The ecryptfs inode | |
67 | * | |
4981e081 MH |
68 | * This is used during the final destruction of the inode. All |
69 | * allocation of memory related to the inode, including allocated | |
70 | * memory in the crypt_stat struct, will be released here. This | |
71 | * function also fput()'s the persistent file for the lower inode. | |
237fead6 MH |
72 | * There should be no chance that this deallocation will be missed. |
73 | */ | |
74 | static void ecryptfs_destroy_inode(struct inode *inode) | |
75 | { | |
76 | struct ecryptfs_inode_info *inode_info; | |
77 | ||
78 | inode_info = ecryptfs_inode_to_private(inode); | |
4981e081 MH |
79 | mutex_lock(&inode_info->lower_file_mutex); |
80 | if (inode_info->lower_file) { | |
81 | struct dentry *lower_dentry = | |
82 | inode_info->lower_file->f_dentry; | |
83 | ||
84 | BUG_ON(!lower_dentry); | |
85 | if (lower_dentry->d_inode) { | |
86 | fput(inode_info->lower_file); | |
87 | inode_info->lower_file = NULL; | |
88 | d_drop(lower_dentry); | |
89 | d_delete(lower_dentry); | |
90 | } | |
91 | } | |
92 | mutex_unlock(&inode_info->lower_file_mutex); | |
fcd12835 | 93 | ecryptfs_destroy_crypt_stat(&inode_info->crypt_stat); |
237fead6 MH |
94 | kmem_cache_free(ecryptfs_inode_info_cache, inode_info); |
95 | } | |
96 | ||
97 | /** | |
98 | * ecryptfs_init_inode | |
99 | * @inode: The ecryptfs inode | |
100 | * | |
101 | * Set up the ecryptfs inode. | |
102 | */ | |
103 | void ecryptfs_init_inode(struct inode *inode, struct inode *lower_inode) | |
104 | { | |
105 | ecryptfs_set_inode_lower(inode, lower_inode); | |
106 | inode->i_ino = lower_inode->i_ino; | |
107 | inode->i_version++; | |
108 | inode->i_op = &ecryptfs_main_iops; | |
109 | inode->i_fop = &ecryptfs_main_fops; | |
110 | inode->i_mapping->a_ops = &ecryptfs_aops; | |
111 | } | |
112 | ||
113 | /** | |
114 | * ecryptfs_put_super | |
115 | * @sb: Pointer to the ecryptfs super block | |
116 | * | |
117 | * Final actions when unmounting a file system. | |
118 | * This will handle deallocation and release of our private data. | |
119 | */ | |
120 | static void ecryptfs_put_super(struct super_block *sb) | |
121 | { | |
122 | struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb); | |
123 | ||
fcd12835 | 124 | ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat); |
237fead6 MH |
125 | kmem_cache_free(ecryptfs_sb_info_cache, sb_info); |
126 | ecryptfs_set_superblock_private(sb, NULL); | |
127 | } | |
128 | ||
129 | /** | |
130 | * ecryptfs_statfs | |
131 | * @sb: The ecryptfs super block | |
132 | * @buf: The struct kstatfs to fill in with stats | |
133 | * | |
134 | * Get the filesystem statistics. Currently, we let this pass right through | |
135 | * to the lower filesystem and take no action ourselves. | |
136 | */ | |
137 | static int ecryptfs_statfs(struct dentry *dentry, struct kstatfs *buf) | |
138 | { | |
139 | return vfs_statfs(ecryptfs_dentry_to_lower(dentry), buf); | |
140 | } | |
141 | ||
142 | /** | |
143 | * ecryptfs_clear_inode | |
144 | * @inode - The ecryptfs inode | |
145 | * | |
146 | * Called by iput() when the inode reference count reached zero | |
147 | * and the inode is not hashed anywhere. Used to clear anything | |
148 | * that needs to be, before the inode is completely destroyed and put | |
149 | * on the inode free list. We use this to drop out reference to the | |
150 | * lower inode. | |
151 | */ | |
152 | static void ecryptfs_clear_inode(struct inode *inode) | |
153 | { | |
154 | iput(ecryptfs_inode_to_lower(inode)); | |
155 | } | |
156 | ||
237fead6 MH |
157 | /** |
158 | * ecryptfs_show_options | |
159 | * | |
160 | * Prints the directory we are currently mounted over. | |
161 | * Returns zero on success; non-zero otherwise | |
162 | */ | |
163 | static int ecryptfs_show_options(struct seq_file *m, struct vfsmount *mnt) | |
164 | { | |
165 | struct super_block *sb = mnt->mnt_sb; | |
166 | struct dentry *lower_root_dentry = ecryptfs_dentry_to_lower(sb->s_root); | |
167 | struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(sb->s_root); | |
168 | char *tmp_page; | |
169 | char *path; | |
170 | int rc = 0; | |
171 | ||
172 | tmp_page = (char *)__get_free_page(GFP_KERNEL); | |
173 | if (!tmp_page) { | |
174 | rc = -ENOMEM; | |
175 | goto out; | |
176 | } | |
177 | path = d_path(lower_root_dentry, lower_mnt, tmp_page, PAGE_SIZE); | |
178 | if (IS_ERR(path)) { | |
179 | rc = PTR_ERR(path); | |
180 | goto out; | |
181 | } | |
182 | seq_printf(m, ",dir=%s", path); | |
183 | free_page((unsigned long)tmp_page); | |
184 | out: | |
185 | return rc; | |
186 | } | |
187 | ||
ee9b6d61 | 188 | const struct super_operations ecryptfs_sops = { |
237fead6 MH |
189 | .alloc_inode = ecryptfs_alloc_inode, |
190 | .destroy_inode = ecryptfs_destroy_inode, | |
191 | .drop_inode = generic_delete_inode, | |
192 | .put_super = ecryptfs_put_super, | |
193 | .statfs = ecryptfs_statfs, | |
194 | .remount_fs = NULL, | |
195 | .clear_inode = ecryptfs_clear_inode, | |
237fead6 MH |
196 | .show_options = ecryptfs_show_options |
197 | }; |