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authorJosef Bacik <jbacik@redhat.com>2007-11-16 11:45:54 -0500
committerChris Mason <chris.mason@oracle.com>2008-09-25 11:03:57 -0400
commit5103e947b9b7ac18ddb21a04ee3486e94c6504d7 (patch)
tree5d7c0c9ce1d57b988165f87c7bae304cb339589c /fs/btrfs/xattr.c
parent0591fb56fb732c7bf500d1446d0bf927046d7002 (diff)
xattr support for btrfs
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/xattr.c')
-rw-r--r--fs/btrfs/xattr.c497
1 files changed, 497 insertions, 0 deletions
diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c
new file mode 100644
index 000000000000..f4ac5e0bbad1
--- /dev/null
+++ b/fs/btrfs/xattr.c
@@ -0,0 +1,497 @@
1/*
2 * Copyright (C) 2007 Red Hat. All rights reserved.
3 *
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.
7 *
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.
12 *
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.
17 */
18
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 "ctree.h"
25#include "btrfs_inode.h"
26#include "transaction.h"
27#include "xattr.h"
28#include "disk-io.h"
29
30static struct xattr_handler *btrfs_xattr_handler_map[] = {
31 [BTRFS_XATTR_INDEX_USER] = &btrfs_xattr_user_handler,
32 [BTRFS_XATTR_INDEX_POSIX_ACL_ACCESS] = &btrfs_xattr_acl_access_handler,
33 [BTRFS_XATTR_INDEX_POSIX_ACL_DEFAULT] = &btrfs_xattr_acl_default_handler,
34 [BTRFS_XATTR_INDEX_TRUSTED] = &btrfs_xattr_trusted_handler,
35 [BTRFS_XATTR_INDEX_SECURITY] = &btrfs_xattr_security_handler,
36 [BTRFS_XATTR_INDEX_SYSTEM] = &btrfs_xattr_system_handler,
37};
38
39struct xattr_handler *btrfs_xattr_handlers[] = {
40 &btrfs_xattr_user_handler,
41 &btrfs_xattr_acl_access_handler,
42 &btrfs_xattr_acl_default_handler,
43 &btrfs_xattr_trusted_handler,
44 &btrfs_xattr_security_handler,
45 &btrfs_xattr_system_handler,
46 NULL,
47};
48
49/*
50 * @param name - the xattr name
51 * @return - the xattr_handler for the xattr, NULL if its not found
52 *
53 * use this with listxattr where we don't already know the type of xattr we
54 * have
55 */
56static struct xattr_handler *find_btrfs_xattr_handler(struct extent_buffer *l,
57 unsigned long name_ptr,
58 u16 name_len)
59{
60 struct xattr_handler *handler = NULL;
61 int i = 0;
62
63 for (handler = btrfs_xattr_handlers[i]; handler != NULL; i++,
64 handler = btrfs_xattr_handlers[i]) {
65 u16 prefix_len = strlen(handler->prefix);
66
67 if (name_len < prefix_len)
68 continue;
69
70 if (memcmp_extent_buffer(l, handler->prefix, name_ptr,
71 prefix_len) == 0)
72 break;
73 }
74
75 return handler;
76}
77
78/*
79 * @param name_index - the index for the xattr handler
80 * @return the xattr_handler if we found it, NULL otherwise
81 *
82 * use this if we know the type of the xattr already
83 */
84static struct xattr_handler *btrfs_xattr_handler(int name_index)
85{
86 struct xattr_handler *handler = NULL;
87
88 if (name_index >= 0 &&
89 name_index < ARRAY_SIZE(btrfs_xattr_handler_map))
90 handler = btrfs_xattr_handler_map[name_index];
91
92 return handler;
93}
94
95static inline char *get_name(const char *name, int name_index)
96{
97 char *ret = NULL;
98 struct xattr_handler *handler = btrfs_xattr_handler(name_index);
99 int prefix_len;
100
101 if (!handler)
102 return ret;
103
104 prefix_len = strlen(handler->prefix);
105
106 ret = kmalloc(strlen(name) + prefix_len + 1, GFP_KERNEL);
107 if (!ret)
108 return ret;
109
110 memcpy(ret, handler->prefix, prefix_len);
111 memcpy(ret+prefix_len, name, strlen(name));
112 ret[prefix_len + strlen(name)] = '\0';
113
114 return ret;
115}
116
117size_t btrfs_xattr_generic_list(struct inode *inode, char *list,
118 size_t list_size, const char *name,
119 size_t name_len)
120{
121 if (list && (name_len+1) <= list_size) {
122 memcpy(list, name, name_len);
123 list[name_len] = '\0';
124 } else
125 return -ERANGE;
126
127 return name_len+1;
128}
129
130ssize_t btrfs_xattr_get(struct inode *inode, int name_index,
131 const char *attr_name, void *buffer, size_t size)
132{
133 struct btrfs_dir_item *di;
134 struct btrfs_root *root = BTRFS_I(inode)->root;
135 struct btrfs_path *path;
136 struct extent_buffer *leaf;
137 struct xattr_handler *handler = btrfs_xattr_handler(name_index);
138 int ret = 0;
139 unsigned long data_ptr;
140 char *name;
141
142 if (!handler)
143 return -EOPNOTSUPP;
144
145 /* just in case... */
146 if (*attr_name == '\0')
147 return -EINVAL;
148
149 name = get_name(attr_name, name_index);
150 if (!name)
151 return -ENOMEM;
152
153 path = btrfs_alloc_path();
154 if (!path) {
155 kfree(name);
156 return -ENOMEM;
157 }
158
159 mutex_lock(&root->fs_info->fs_mutex);
160 /* lookup the xattr by name */
161 di = btrfs_lookup_xattr(NULL, root, path, inode->i_ino, name,
162 strlen(name), 0);
163 if (!di || IS_ERR(di)) {
164 ret = -ENODATA;
165 goto out;
166 }
167
168 leaf = path->nodes[0];
169 /* if size is 0, that means we want the size of the attr */
170 if (!size) {
171 ret = btrfs_dir_data_len(leaf, di);
172 goto out;
173 }
174
175 /* now get the data out of our dir_item */
176 if (btrfs_dir_data_len(leaf, di) > size) {
177 ret = -ERANGE;
178 goto out;
179 }
180 data_ptr = (unsigned long)((char *)(di + 1) +
181 btrfs_dir_name_len(leaf, di));
182 read_extent_buffer(leaf, buffer, data_ptr,
183 btrfs_dir_name_len(leaf, di));
184 ret = btrfs_dir_data_len(leaf, di);
185
186out:
187 mutex_unlock(&root->fs_info->fs_mutex);
188 kfree(name);
189 btrfs_free_path(path);
190 return ret;
191}
192
193int btrfs_xattr_set(struct inode *inode, int name_index,
194 const char *attr_name, const void *value, size_t size,
195 int flags)
196{
197 struct btrfs_dir_item *di;
198 struct btrfs_root *root = BTRFS_I(inode)->root;
199 struct btrfs_trans_handle *trans;
200 struct btrfs_path *path;
201 struct xattr_handler *handler = btrfs_xattr_handler(name_index);
202 char *name;
203 int ret = 0, mod = 0;
204
205 if (!handler)
206 return -EOPNOTSUPP;
207
208 /* just in case... */
209 if (*attr_name == '\0')
210 return -EINVAL;
211
212 name = get_name(attr_name, name_index);
213 if (!name)
214 return -ENOMEM;
215
216 path = btrfs_alloc_path();
217 if (!path) {
218 kfree(name);
219 return -ENOMEM;
220 }
221
222 mutex_lock(&root->fs_info->fs_mutex);
223 trans = btrfs_start_transaction(root, 1);
224 btrfs_set_trans_block_group(trans, inode);
225
226 /* first lets see if we already have this xattr */
227 di = btrfs_lookup_xattr(trans, root, path, inode->i_ino, name,
228 strlen(name), -1);
229 if (IS_ERR(di)) {
230 ret = PTR_ERR(di);
231 goto out;
232 }
233
234 /* ok we already have this xattr, lets remove it */
235 if (di) {
236 /* if we want create only exit */
237 if (flags & XATTR_CREATE) {
238 ret = -EEXIST;
239 goto out;
240 }
241
242 ret = btrfs_delete_one_dir_name(trans, root, path, di);
243 if (ret)
244 goto out;
245 btrfs_release_path(root, path);
246
247 /* if we don't have a value then we are removing the xattr */
248 if (!value) {
249 mod = 1;
250 goto out;
251 }
252 } else if (flags & XATTR_REPLACE) {
253 /* we couldn't find the attr to replace, so error out */
254 ret = -ENODATA;
255 goto out;
256 }
257
258 /* ok we have to create a completely new xattr */
259 ret = btrfs_insert_xattr_item(trans, root, name, strlen(name),
260 value, size, inode->i_ino);
261 if (ret)
262 goto out;
263 mod = 1;
264
265out:
266 if (mod) {
267 inode->i_ctime = CURRENT_TIME;
268 ret = btrfs_update_inode(trans, root, inode);
269 }
270
271 btrfs_end_transaction(trans, root);
272 mutex_unlock(&root->fs_info->fs_mutex);
273 kfree(name);
274 btrfs_free_path(path);
275
276 return ret;
277}
278
279ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
280{
281 struct btrfs_key key, found_key;
282 struct inode *inode = dentry->d_inode;
283 struct btrfs_root *root = BTRFS_I(inode)->root;
284 struct btrfs_path *path;
285 struct btrfs_item *item;
286 struct extent_buffer *leaf;
287 struct btrfs_dir_item *di;
288 struct xattr_handler *handler;
289 int ret = 0, slot, advance;
290 size_t total_size = 0, size_left = size, written;
291 unsigned long name_ptr;
292 char *name;
293 u32 nritems;
294
295 /*
296 * ok we want all objects associated with this id.
297 * NOTE: we set key.offset = 0; because we want to start with the
298 * first xattr that we find and walk forward
299 */
300 key.objectid = inode->i_ino;
301 btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
302 key.offset = 0;
303
304 path = btrfs_alloc_path();
305 path->reada = 2;
306 if (!path)
307 return -ENOMEM;
308
309 mutex_lock(&root->fs_info->fs_mutex);
310
311 /* search for our xattrs */
312 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
313 if (ret < 0)
314 goto err;
315 ret = 0;
316 advance = 0;
317 while (1) {
318 leaf = path->nodes[0];
319 nritems = btrfs_header_nritems(leaf);
320 slot = path->slots[0];
321
322 /* this is where we start walking through the path */
323 if (advance || slot >= nritems) {
324 /*
325 * if we've reached the last slot in this leaf we need
326 * to go to the next leaf and reset everything
327 */
328 if (slot >= nritems-1) {
329 ret = btrfs_next_leaf(root, path);
330 if (ret)
331 break;
332 leaf = path->nodes[0];
333 nritems = btrfs_header_nritems(leaf);
334 slot = path->slots[0];
335 } else {
336 /*
337 * just walking through the slots on this leaf
338 */
339 slot++;
340 path->slots[0]++;
341 }
342 }
343 advance = 1;
344
345 item = btrfs_item_nr(leaf, slot);
346 btrfs_item_key_to_cpu(leaf, &found_key, slot);
347
348 /* check to make sure this item is what we want */
349 if (found_key.objectid != key.objectid)
350 break;
351 if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
352 break;
353
354 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
355
356 total_size += btrfs_dir_name_len(leaf, di)+1;
357
358 /* we are just looking for how big our buffer needs to be */
359 if (!size)
360 continue;
361
362 /* find our handler for this xattr */
363 name_ptr = (unsigned long)(di + 1);
364 handler = find_btrfs_xattr_handler(leaf, name_ptr,
365 btrfs_dir_name_len(leaf, di));
366 if (!handler) {
367 printk(KERN_ERR "btrfs: unsupported xattr found\n");
368 continue;
369 }
370
371 name = kmalloc(btrfs_dir_name_len(leaf, di), GFP_KERNEL);
372 read_extent_buffer(leaf, name, name_ptr,
373 btrfs_dir_name_len(leaf, di));
374
375 /* call the list function associated with this xattr */
376 written = handler->list(inode, buffer, size_left, name,
377 btrfs_dir_name_len(leaf, di));
378 kfree(name);
379
380 if (written < 0) {
381 ret = -ERANGE;
382 break;
383 }
384
385 size_left -= written;
386 buffer += written;
387 }
388 ret = total_size;
389
390err:
391 mutex_unlock(&root->fs_info->fs_mutex);
392 btrfs_free_path(path);
393
394 return ret;
395}
396
397/*
398 * delete all the xattrs associated with the inode. fs_mutex should be
399 * held when we come into here
400 */
401int btrfs_delete_xattrs(struct btrfs_trans_handle *trans,
402 struct btrfs_root *root, struct inode *inode)
403{
404 struct btrfs_path *path;
405 struct btrfs_key key, found_key;
406 struct btrfs_item *item;
407 struct extent_buffer *leaf;
408 int ret;
409
410 path = btrfs_alloc_path();
411 if (!path)
412 return -ENOMEM;
413
414 key.objectid = inode->i_ino;
415 btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
416 key.offset = (u64)-1;
417
418 while(1) {
419 /* look for our next xattr */
420 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
421 if (ret < 0)
422 goto out;
423 BUG_ON(ret == 0);
424
425 if (path->slots[0] == 0)
426 break;
427
428 path->slots[0]--;
429 leaf = path->nodes[0];
430 item = btrfs_item_nr(leaf, path->slots[0]);
431 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
432
433 if (found_key.objectid != key.objectid)
434 break;
435 if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
436 break;
437
438 ret = btrfs_del_item(trans, root, path);
439 BUG_ON(ret);
440 btrfs_release_path(root, path);
441 }
442 ret = 0;
443out:
444 btrfs_free_path(path);
445
446 return ret;
447}
448
449/*
450 * Handler functions
451 */
452#define BTRFS_XATTR_SETGET_FUNCS(name, index) \
453static int btrfs_xattr_##name##_get(struct inode *inode, \
454 const char *name, void *value, \
455 size_t size) \
456{ \
457 return btrfs_xattr_get(inode, index, name, value, size); \
458} \
459static int btrfs_xattr_##name##_set(struct inode *inode, \
460 const char *name, const void *value,\
461 size_t size, int flags) \
462{ \
463 return btrfs_xattr_set(inode, index, name, value, size, flags); \
464} \
465
466BTRFS_XATTR_SETGET_FUNCS(security, BTRFS_XATTR_INDEX_SECURITY);
467BTRFS_XATTR_SETGET_FUNCS(system, BTRFS_XATTR_INDEX_SYSTEM);
468BTRFS_XATTR_SETGET_FUNCS(user, BTRFS_XATTR_INDEX_USER);
469BTRFS_XATTR_SETGET_FUNCS(trusted, BTRFS_XATTR_INDEX_TRUSTED);
470
471struct xattr_handler btrfs_xattr_security_handler = {
472 .prefix = XATTR_SECURITY_PREFIX,
473 .list = btrfs_xattr_generic_list,
474 .get = btrfs_xattr_security_get,
475 .set = btrfs_xattr_security_set,
476};
477
478struct xattr_handler btrfs_xattr_system_handler = {
479 .prefix = XATTR_SYSTEM_PREFIX,
480 .list = btrfs_xattr_generic_list,
481 .get = btrfs_xattr_system_get,
482 .set = btrfs_xattr_system_set,
483};
484
485struct xattr_handler btrfs_xattr_user_handler = {
486 .prefix = XATTR_USER_PREFIX,
487 .list = btrfs_xattr_generic_list,
488 .get = btrfs_xattr_user_get,
489 .set = btrfs_xattr_user_set,
490};
491
492struct xattr_handler btrfs_xattr_trusted_handler = {
493 .prefix = XATTR_USER_PREFIX,
494 .list = btrfs_xattr_generic_list,
495 .get = btrfs_xattr_trusted_get,
496 .set = btrfs_xattr_trusted_set,
497};