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>
21 #include <linux/slab.h>
22 #include <linux/rwsem.h>
23 #include <linux/xattr.h>
24 #include <linux/security.h>
25 #include <linux/posix_acl_xattr.h>
27 #include "btrfs_inode.h"
28 #include "transaction.h"
35 ssize_t __btrfs_getxattr(struct inode *inode, const char *name,
36 void *buffer, size_t size)
38 struct btrfs_dir_item *di;
39 struct btrfs_root *root = BTRFS_I(inode)->root;
40 struct btrfs_path *path;
41 struct extent_buffer *leaf;
43 unsigned long data_ptr;
45 path = btrfs_alloc_path();
49 /* lookup the xattr by name */
50 di = btrfs_lookup_xattr(NULL, root, path, btrfs_ino(BTRFS_I(inode)),
51 name, strlen(name), 0);
55 } else if (IS_ERR(di)) {
60 leaf = path->nodes[0];
61 /* if size is 0, that means we want the size of the attr */
63 ret = btrfs_dir_data_len(leaf, di);
67 /* now get the data out of our dir_item */
68 if (btrfs_dir_data_len(leaf, di) > size) {
74 * The way things are packed into the leaf is like this
75 * |struct btrfs_dir_item|name|data|
76 * where name is the xattr name, so security.foo, and data is the
77 * content of the xattr. data_ptr points to the location in memory
78 * where the data starts in the in memory leaf
80 data_ptr = (unsigned long)((char *)(di + 1) +
81 btrfs_dir_name_len(leaf, di));
82 read_extent_buffer(leaf, buffer, data_ptr,
83 btrfs_dir_data_len(leaf, di));
84 ret = btrfs_dir_data_len(leaf, di);
87 btrfs_free_path(path);
91 static int do_setxattr(struct btrfs_trans_handle *trans,
92 struct inode *inode, const char *name,
93 const void *value, size_t size, int flags)
95 struct btrfs_dir_item *di = NULL;
96 struct btrfs_root *root = BTRFS_I(inode)->root;
97 struct btrfs_fs_info *fs_info = root->fs_info;
98 struct btrfs_path *path;
99 size_t name_len = strlen(name);
102 if (name_len + size > BTRFS_MAX_XATTR_SIZE(root->fs_info))
105 path = btrfs_alloc_path();
108 path->skip_release_on_error = 1;
111 di = btrfs_lookup_xattr(trans, root, path,
112 btrfs_ino(BTRFS_I(inode)), name, name_len, -1);
113 if (!di && (flags & XATTR_REPLACE))
118 ret = btrfs_delete_one_dir_name(trans, root, path, di);
123 * For a replace we can't just do the insert blindly.
124 * Do a lookup first (read-only btrfs_search_slot), and return if xattr
125 * doesn't exist. If it exists, fall down below to the insert/replace
126 * path - we can't race with a concurrent xattr delete, because the VFS
127 * locks the inode's i_mutex before calling setxattr or removexattr.
129 if (flags & XATTR_REPLACE) {
130 ASSERT(inode_is_locked(inode));
131 di = btrfs_lookup_xattr(NULL, root, path,
132 btrfs_ino(BTRFS_I(inode)), name, name_len, 0);
139 btrfs_release_path(path);
143 ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(BTRFS_I(inode)),
144 name, name_len, value, size);
145 if (ret == -EOVERFLOW) {
147 * We have an existing item in a leaf, split_leaf couldn't
148 * expand it. That item might have or not a dir_item that
149 * matches our target xattr, so lets check.
152 btrfs_assert_tree_locked(path->nodes[0]);
153 di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
154 if (!di && !(flags & XATTR_REPLACE)) {
158 } else if (ret == -EEXIST) {
160 di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
161 ASSERT(di); /* logic error */
166 if (di && (flags & XATTR_CREATE)) {
173 * We're doing a replace, and it must be atomic, that is, at
174 * any point in time we have either the old or the new xattr
175 * value in the tree. We don't want readers (getxattr and
176 * listxattrs) to miss a value, this is specially important
179 const int slot = path->slots[0];
180 struct extent_buffer *leaf = path->nodes[0];
181 const u16 old_data_len = btrfs_dir_data_len(leaf, di);
182 const u32 item_size = btrfs_item_size_nr(leaf, slot);
183 const u32 data_size = sizeof(*di) + name_len + size;
184 struct btrfs_item *item;
185 unsigned long data_ptr;
188 if (size > old_data_len) {
189 if (btrfs_leaf_free_space(fs_info, leaf) <
190 (size - old_data_len)) {
196 if (old_data_len + name_len + sizeof(*di) == item_size) {
197 /* No other xattrs packed in the same leaf item. */
198 if (size > old_data_len)
199 btrfs_extend_item(fs_info, path,
200 size - old_data_len);
201 else if (size < old_data_len)
202 btrfs_truncate_item(fs_info, path,
205 /* There are other xattrs packed in the same item. */
206 ret = btrfs_delete_one_dir_name(trans, root, path, di);
209 btrfs_extend_item(fs_info, path, data_size);
212 item = btrfs_item_nr(slot);
213 ptr = btrfs_item_ptr(leaf, slot, char);
214 ptr += btrfs_item_size(leaf, item) - data_size;
215 di = (struct btrfs_dir_item *)ptr;
216 btrfs_set_dir_data_len(leaf, di, size);
217 data_ptr = ((unsigned long)(di + 1)) + name_len;
218 write_extent_buffer(leaf, value, data_ptr, size);
219 btrfs_mark_buffer_dirty(leaf);
222 * Insert, and we had space for the xattr, so path->slots[0] is
223 * where our xattr dir_item is and btrfs_insert_xattr_item()
228 btrfs_free_path(path);
233 * @value: "" makes the attribute to empty, NULL removes it
235 int __btrfs_setxattr(struct btrfs_trans_handle *trans,
236 struct inode *inode, const char *name,
237 const void *value, size_t size, int flags)
239 struct btrfs_root *root = BTRFS_I(inode)->root;
242 if (btrfs_root_readonly(root))
246 return do_setxattr(trans, inode, name, value, size, flags);
248 trans = btrfs_start_transaction(root, 2);
250 return PTR_ERR(trans);
252 ret = do_setxattr(trans, inode, name, value, size, flags);
256 inode_inc_iversion(inode);
257 inode->i_ctime = current_time(inode);
258 set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
259 ret = btrfs_update_inode(trans, root, inode);
262 btrfs_end_transaction(trans);
266 ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
268 struct btrfs_key key;
269 struct inode *inode = d_inode(dentry);
270 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
271 struct btrfs_root *root = BTRFS_I(inode)->root;
272 struct btrfs_path *path;
274 size_t total_size = 0, size_left = size;
277 * ok we want all objects associated with this id.
278 * NOTE: we set key.offset = 0; because we want to start with the
279 * first xattr that we find and walk forward
281 key.objectid = btrfs_ino(BTRFS_I(inode));
282 key.type = BTRFS_XATTR_ITEM_KEY;
285 path = btrfs_alloc_path();
288 path->reada = READA_FORWARD;
290 /* search for our xattrs */
291 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
296 struct extent_buffer *leaf;
298 struct btrfs_dir_item *di;
299 struct btrfs_key found_key;
303 leaf = path->nodes[0];
304 slot = path->slots[0];
306 /* this is where we start walking through the path */
307 if (slot >= btrfs_header_nritems(leaf)) {
309 * if we've reached the last slot in this leaf we need
310 * to go to the next leaf and reset everything
312 ret = btrfs_next_leaf(root, path);
320 btrfs_item_key_to_cpu(leaf, &found_key, slot);
322 /* check to make sure this item is what we want */
323 if (found_key.objectid != key.objectid)
325 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
327 if (found_key.type < BTRFS_XATTR_ITEM_KEY)
330 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
331 item_size = btrfs_item_size_nr(leaf, slot);
333 while (cur < item_size) {
334 u16 name_len = btrfs_dir_name_len(leaf, di);
335 u16 data_len = btrfs_dir_data_len(leaf, di);
336 u32 this_len = sizeof(*di) + name_len + data_len;
337 unsigned long name_ptr = (unsigned long)(di + 1);
339 if (verify_dir_item(fs_info, leaf, di)) {
344 total_size += name_len + 1;
346 * We are just looking for how big our buffer needs to
352 if (!buffer || (name_len + 1) > size_left) {
357 read_extent_buffer(leaf, buffer, name_ptr, name_len);
358 buffer[name_len] = '\0';
360 size_left -= name_len + 1;
361 buffer += name_len + 1;
364 di = (struct btrfs_dir_item *)((char *)di + this_len);
372 btrfs_free_path(path);
377 static int btrfs_xattr_handler_get(const struct xattr_handler *handler,
378 struct dentry *unused, struct inode *inode,
379 const char *name, void *buffer, size_t size)
381 name = xattr_full_name(handler, name);
382 return __btrfs_getxattr(inode, name, buffer, size);
385 static int btrfs_xattr_handler_set(const struct xattr_handler *handler,
386 struct dentry *unused, struct inode *inode,
387 const char *name, const void *buffer,
388 size_t size, int flags)
390 name = xattr_full_name(handler, name);
391 return __btrfs_setxattr(NULL, inode, name, buffer, size, flags);
394 static int btrfs_xattr_handler_set_prop(const struct xattr_handler *handler,
395 struct dentry *unused, struct inode *inode,
396 const char *name, const void *value,
397 size_t size, int flags)
399 name = xattr_full_name(handler, name);
400 return btrfs_set_prop(inode, name, value, size, flags);
403 static const struct xattr_handler btrfs_security_xattr_handler = {
404 .prefix = XATTR_SECURITY_PREFIX,
405 .get = btrfs_xattr_handler_get,
406 .set = btrfs_xattr_handler_set,
409 static const struct xattr_handler btrfs_trusted_xattr_handler = {
410 .prefix = XATTR_TRUSTED_PREFIX,
411 .get = btrfs_xattr_handler_get,
412 .set = btrfs_xattr_handler_set,
415 static const struct xattr_handler btrfs_user_xattr_handler = {
416 .prefix = XATTR_USER_PREFIX,
417 .get = btrfs_xattr_handler_get,
418 .set = btrfs_xattr_handler_set,
421 static const struct xattr_handler btrfs_btrfs_xattr_handler = {
422 .prefix = XATTR_BTRFS_PREFIX,
423 .get = btrfs_xattr_handler_get,
424 .set = btrfs_xattr_handler_set_prop,
427 const struct xattr_handler *btrfs_xattr_handlers[] = {
428 &btrfs_security_xattr_handler,
429 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
430 &posix_acl_access_xattr_handler,
431 &posix_acl_default_xattr_handler,
433 &btrfs_trusted_xattr_handler,
434 &btrfs_user_xattr_handler,
435 &btrfs_btrfs_xattr_handler,
439 static int btrfs_initxattrs(struct inode *inode,
440 const struct xattr *xattr_array, void *fs_info)
442 const struct xattr *xattr;
443 struct btrfs_trans_handle *trans = fs_info;
447 for (xattr = xattr_array; xattr->name != NULL; xattr++) {
448 name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
449 strlen(xattr->name) + 1, GFP_KERNEL);
454 strcpy(name, XATTR_SECURITY_PREFIX);
455 strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
456 err = __btrfs_setxattr(trans, inode, name,
457 xattr->value, xattr->value_len, 0);
465 int btrfs_xattr_security_init(struct btrfs_trans_handle *trans,
466 struct inode *inode, struct inode *dir,
467 const struct qstr *qstr)
469 return security_inode_init_security(inode, dir, qstr,
470 &btrfs_initxattrs, trans);