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Source at commit caeeeecfdaeada2998eb3c29c3ebd59afb79ef06 created 16 years 2 months ago. By Michael Halcrow, eCryptfs: fix dentry handling on create error, unlink, and inode destroy | |
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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 | * 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/file.h> |
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 | { |
50 | struct ecryptfs_inode_info *inode_info; |
51 | struct inode *inode = NULL; |
52 | |
53 | inode_info = kmem_cache_alloc(ecryptfs_inode_info_cache, GFP_KERNEL); |
54 | if (unlikely(!inode_info)) |
55 | goto out; |
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; |
60 | out: |
61 | return inode; |
62 | } |
63 | |
64 | /** |
65 | * ecryptfs_destroy_inode |
66 | * @inode: The ecryptfs inode |
67 | * |
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. |
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); |
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 | } |
90 | } |
91 | mutex_unlock(&inode_info->lower_file_mutex); |
92 | ecryptfs_destroy_crypt_stat(&inode_info->crypt_stat); |
93 | kmem_cache_free(ecryptfs_inode_info_cache, inode_info); |
94 | } |
95 | |
96 | /** |
97 | * ecryptfs_init_inode |
98 | * @inode: The ecryptfs inode |
99 | * |
100 | * Set up the ecryptfs inode. |
101 | */ |
102 | void ecryptfs_init_inode(struct inode *inode, struct inode *lower_inode) |
103 | { |
104 | ecryptfs_set_inode_lower(inode, lower_inode); |
105 | inode->i_ino = lower_inode->i_ino; |
106 | inode->i_version++; |
107 | inode->i_op = &ecryptfs_main_iops; |
108 | inode->i_fop = &ecryptfs_main_fops; |
109 | inode->i_mapping->a_ops = &ecryptfs_aops; |
110 | } |
111 | |
112 | /** |
113 | * ecryptfs_put_super |
114 | * @sb: Pointer to the ecryptfs super block |
115 | * |
116 | * Final actions when unmounting a file system. |
117 | * This will handle deallocation and release of our private data. |
118 | */ |
119 | static void ecryptfs_put_super(struct super_block *sb) |
120 | { |
121 | struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb); |
122 | |
123 | ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat); |
124 | kmem_cache_free(ecryptfs_sb_info_cache, sb_info); |
125 | ecryptfs_set_superblock_private(sb, NULL); |
126 | } |
127 | |
128 | /** |
129 | * ecryptfs_statfs |
130 | * @sb: The ecryptfs super block |
131 | * @buf: The struct kstatfs to fill in with stats |
132 | * |
133 | * Get the filesystem statistics. Currently, we let this pass right through |
134 | * to the lower filesystem and take no action ourselves. |
135 | */ |
136 | static int ecryptfs_statfs(struct dentry *dentry, struct kstatfs *buf) |
137 | { |
138 | return vfs_statfs(ecryptfs_dentry_to_lower(dentry), buf); |
139 | } |
140 | |
141 | /** |
142 | * ecryptfs_clear_inode |
143 | * @inode - The ecryptfs inode |
144 | * |
145 | * Called by iput() when the inode reference count reached zero |
146 | * and the inode is not hashed anywhere. Used to clear anything |
147 | * that needs to be, before the inode is completely destroyed and put |
148 | * on the inode free list. We use this to drop out reference to the |
149 | * lower inode. |
150 | */ |
151 | static void ecryptfs_clear_inode(struct inode *inode) |
152 | { |
153 | iput(ecryptfs_inode_to_lower(inode)); |
154 | } |
155 | |
156 | /** |
157 | * ecryptfs_show_options |
158 | * |
159 | * Prints the directory we are currently mounted over. |
160 | * Returns zero on success; non-zero otherwise |
161 | */ |
162 | static int ecryptfs_show_options(struct seq_file *m, struct vfsmount *mnt) |
163 | { |
164 | struct super_block *sb = mnt->mnt_sb; |
165 | struct dentry *lower_root_dentry = ecryptfs_dentry_to_lower(sb->s_root); |
166 | struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(sb->s_root); |
167 | char *tmp_page; |
168 | char *path; |
169 | int rc = 0; |
170 | |
171 | tmp_page = (char *)__get_free_page(GFP_KERNEL); |
172 | if (!tmp_page) { |
173 | rc = -ENOMEM; |
174 | goto out; |
175 | } |
176 | path = d_path(lower_root_dentry, lower_mnt, tmp_page, PAGE_SIZE); |
177 | if (IS_ERR(path)) { |
178 | rc = PTR_ERR(path); |
179 | goto out; |
180 | } |
181 | seq_printf(m, ",dir=%s", path); |
182 | free_page((unsigned long)tmp_page); |
183 | out: |
184 | return rc; |
185 | } |
186 | |
187 | const struct super_operations ecryptfs_sops = { |
188 | .alloc_inode = ecryptfs_alloc_inode, |
189 | .destroy_inode = ecryptfs_destroy_inode, |
190 | .drop_inode = generic_delete_inode, |
191 | .put_super = ecryptfs_put_super, |
192 | .statfs = ecryptfs_statfs, |
193 | .remount_fs = NULL, |
194 | .clear_inode = ecryptfs_clear_inode, |
195 | .show_options = ecryptfs_show_options |
196 | }; |
197 |
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