Linux 2.6.32.17
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / btrfs / xattr.c
blobb6dd5967c48a2785074f75db2dacd6a7370a9ec2
1 /*
2 * Copyright (C) 2007 Red Hat. All rights reserved.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
19 #include <linux/init.h>
20 #include <linux/fs.h>
21 #include <linux/slab.h>
22 #include <linux/rwsem.h>
23 #include <linux/xattr.h>
24 #include <linux/security.h>
25 #include "ctree.h"
26 #include "btrfs_inode.h"
27 #include "transaction.h"
28 #include "xattr.h"
29 #include "disk-io.h"
32 ssize_t __btrfs_getxattr(struct inode *inode, const char *name,
33 void *buffer, size_t size)
35 struct btrfs_dir_item *di;
36 struct btrfs_root *root = BTRFS_I(inode)->root;
37 struct btrfs_path *path;
38 struct extent_buffer *leaf;
39 int ret = 0;
40 unsigned long data_ptr;
42 path = btrfs_alloc_path();
43 if (!path)
44 return -ENOMEM;
46 /* lookup the xattr by name */
47 di = btrfs_lookup_xattr(NULL, root, path, inode->i_ino, name,
48 strlen(name), 0);
49 if (!di) {
50 ret = -ENODATA;
51 goto out;
52 } else if (IS_ERR(di)) {
53 ret = PTR_ERR(di);
54 goto out;
57 leaf = path->nodes[0];
58 /* if size is 0, that means we want the size of the attr */
59 if (!size) {
60 ret = btrfs_dir_data_len(leaf, di);
61 goto out;
64 /* now get the data out of our dir_item */
65 if (btrfs_dir_data_len(leaf, di) > size) {
66 ret = -ERANGE;
67 goto out;
71 * The way things are packed into the leaf is like this
72 * |struct btrfs_dir_item|name|data|
73 * where name is the xattr name, so security.foo, and data is the
74 * content of the xattr. data_ptr points to the location in memory
75 * where the data starts in the in memory leaf
77 data_ptr = (unsigned long)((char *)(di + 1) +
78 btrfs_dir_name_len(leaf, di));
79 read_extent_buffer(leaf, buffer, data_ptr,
80 btrfs_dir_data_len(leaf, di));
81 ret = btrfs_dir_data_len(leaf, di);
83 out:
84 btrfs_free_path(path);
85 return ret;
88 int __btrfs_setxattr(struct inode *inode, const char *name,
89 const void *value, size_t size, int flags)
91 struct btrfs_dir_item *di;
92 struct btrfs_root *root = BTRFS_I(inode)->root;
93 struct btrfs_trans_handle *trans;
94 struct btrfs_path *path;
95 int ret = 0, mod = 0;
97 path = btrfs_alloc_path();
98 if (!path)
99 return -ENOMEM;
101 trans = btrfs_join_transaction(root, 1);
102 btrfs_set_trans_block_group(trans, inode);
104 /* first lets see if we already have this xattr */
105 di = btrfs_lookup_xattr(trans, root, path, inode->i_ino, name,
106 strlen(name), -1);
107 if (IS_ERR(di)) {
108 ret = PTR_ERR(di);
109 goto out;
112 /* ok we already have this xattr, lets remove it */
113 if (di) {
114 /* if we want create only exit */
115 if (flags & XATTR_CREATE) {
116 ret = -EEXIST;
117 goto out;
120 ret = btrfs_delete_one_dir_name(trans, root, path, di);
121 if (ret)
122 goto out;
123 btrfs_release_path(root, path);
125 /* if we don't have a value then we are removing the xattr */
126 if (!value) {
127 mod = 1;
128 goto out;
130 } else {
131 btrfs_release_path(root, path);
133 if (flags & XATTR_REPLACE) {
134 /* we couldn't find the attr to replace */
135 ret = -ENODATA;
136 goto out;
140 /* ok we have to create a completely new xattr */
141 ret = btrfs_insert_xattr_item(trans, root, name, strlen(name),
142 value, size, inode->i_ino);
143 if (ret)
144 goto out;
145 mod = 1;
147 out:
148 if (mod) {
149 inode->i_ctime = CURRENT_TIME;
150 ret = btrfs_update_inode(trans, root, inode);
153 btrfs_end_transaction(trans, root);
154 btrfs_free_path(path);
155 return ret;
158 ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
160 struct btrfs_key key, found_key;
161 struct inode *inode = dentry->d_inode;
162 struct btrfs_root *root = BTRFS_I(inode)->root;
163 struct btrfs_path *path;
164 struct btrfs_item *item;
165 struct extent_buffer *leaf;
166 struct btrfs_dir_item *di;
167 int ret = 0, slot, advance;
168 size_t total_size = 0, size_left = size;
169 unsigned long name_ptr;
170 size_t name_len;
171 u32 nritems;
174 * ok we want all objects associated with this id.
175 * NOTE: we set key.offset = 0; because we want to start with the
176 * first xattr that we find and walk forward
178 key.objectid = inode->i_ino;
179 btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
180 key.offset = 0;
182 path = btrfs_alloc_path();
183 if (!path)
184 return -ENOMEM;
185 path->reada = 2;
187 /* search for our xattrs */
188 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
189 if (ret < 0)
190 goto err;
191 advance = 0;
192 while (1) {
193 leaf = path->nodes[0];
194 nritems = btrfs_header_nritems(leaf);
195 slot = path->slots[0];
197 /* this is where we start walking through the path */
198 if (advance || slot >= nritems) {
200 * if we've reached the last slot in this leaf we need
201 * to go to the next leaf and reset everything
203 if (slot >= nritems-1) {
204 ret = btrfs_next_leaf(root, path);
205 if (ret)
206 break;
207 leaf = path->nodes[0];
208 nritems = btrfs_header_nritems(leaf);
209 slot = path->slots[0];
210 } else {
212 * just walking through the slots on this leaf
214 slot++;
215 path->slots[0]++;
218 advance = 1;
220 item = btrfs_item_nr(leaf, slot);
221 btrfs_item_key_to_cpu(leaf, &found_key, slot);
223 /* check to make sure this item is what we want */
224 if (found_key.objectid != key.objectid)
225 break;
226 if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
227 break;
229 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
231 name_len = btrfs_dir_name_len(leaf, di);
232 total_size += name_len + 1;
234 /* we are just looking for how big our buffer needs to be */
235 if (!size)
236 continue;
238 if (!buffer || (name_len + 1) > size_left) {
239 ret = -ERANGE;
240 goto err;
243 name_ptr = (unsigned long)(di + 1);
244 read_extent_buffer(leaf, buffer, name_ptr, name_len);
245 buffer[name_len] = '\0';
247 size_left -= name_len + 1;
248 buffer += name_len + 1;
250 ret = total_size;
252 err:
253 btrfs_free_path(path);
255 return ret;
259 * List of handlers for synthetic system.* attributes. All real ondisk
260 * attributes are handled directly.
262 struct xattr_handler *btrfs_xattr_handlers[] = {
263 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
264 &btrfs_xattr_acl_access_handler,
265 &btrfs_xattr_acl_default_handler,
266 #endif
267 NULL,
271 * Check if the attribute is in a supported namespace.
273 * This applied after the check for the synthetic attributes in the system
274 * namespace.
276 static bool btrfs_is_valid_xattr(const char *name)
278 return !strncmp(name, XATTR_SECURITY_PREFIX,
279 XATTR_SECURITY_PREFIX_LEN) ||
280 !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) ||
281 !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) ||
282 !strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
285 ssize_t btrfs_getxattr(struct dentry *dentry, const char *name,
286 void *buffer, size_t size)
289 * If this is a request for a synthetic attribute in the system.*
290 * namespace use the generic infrastructure to resolve a handler
291 * for it via sb->s_xattr.
293 if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
294 return generic_getxattr(dentry, name, buffer, size);
296 if (!btrfs_is_valid_xattr(name))
297 return -EOPNOTSUPP;
298 return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
301 int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value,
302 size_t size, int flags)
305 * If this is a request for a synthetic attribute in the system.*
306 * namespace use the generic infrastructure to resolve a handler
307 * for it via sb->s_xattr.
309 if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
310 return generic_setxattr(dentry, name, value, size, flags);
312 if (!btrfs_is_valid_xattr(name))
313 return -EOPNOTSUPP;
315 if (size == 0)
316 value = ""; /* empty EA, do not remove */
317 return __btrfs_setxattr(dentry->d_inode, name, value, size, flags);
320 int btrfs_removexattr(struct dentry *dentry, const char *name)
323 * If this is a request for a synthetic attribute in the system.*
324 * namespace use the generic infrastructure to resolve a handler
325 * for it via sb->s_xattr.
327 if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
328 return generic_removexattr(dentry, name);
330 if (!btrfs_is_valid_xattr(name))
331 return -EOPNOTSUPP;
332 return __btrfs_setxattr(dentry->d_inode, name, NULL, 0, XATTR_REPLACE);
335 int btrfs_xattr_security_init(struct inode *inode, struct inode *dir)
337 int err;
338 size_t len;
339 void *value;
340 char *suffix;
341 char *name;
343 err = security_inode_init_security(inode, dir, &suffix, &value, &len);
344 if (err) {
345 if (err == -EOPNOTSUPP)
346 return 0;
347 return err;
350 name = kmalloc(XATTR_SECURITY_PREFIX_LEN + strlen(suffix) + 1,
351 GFP_NOFS);
352 if (!name) {
353 err = -ENOMEM;
354 } else {
355 strcpy(name, XATTR_SECURITY_PREFIX);
356 strcpy(name + XATTR_SECURITY_PREFIX_LEN, suffix);
357 err = __btrfs_setxattr(inode, name, value, len, 0);
358 kfree(name);
361 kfree(suffix);
362 kfree(value);
363 return err;