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>
25 #include "btrfs_inode.h"
26 #include "transaction.h"
31 ssize_t __btrfs_getxattr(struct inode *inode, const char *name,
32 void *buffer, size_t size)
34 struct btrfs_dir_item *di;
35 struct btrfs_root *root = BTRFS_I(inode)->root;
36 struct btrfs_path *path;
37 struct extent_buffer *leaf;
39 unsigned long data_ptr;
41 path = btrfs_alloc_path();
45 /* lookup the xattr by name */
46 di = btrfs_lookup_xattr(NULL, root, path, inode->i_ino, name,
51 } else if (IS_ERR(di)) {
56 leaf = path->nodes[0];
57 /* if size is 0, that means we want the size of the attr */
59 ret = btrfs_dir_data_len(leaf, di);
63 /* now get the data out of our dir_item */
64 if (btrfs_dir_data_len(leaf, di) > size) {
70 * The way things are packed into the leaf is like this
71 * |struct btrfs_dir_item|name|data|
72 * where name is the xattr name, so security.foo, and data is the
73 * content of the xattr. data_ptr points to the location in memory
74 * where the data starts in the in memory leaf
76 data_ptr = (unsigned long)((char *)(di + 1) +
77 btrfs_dir_name_len(leaf, di));
78 read_extent_buffer(leaf, buffer, data_ptr,
79 btrfs_dir_data_len(leaf, di));
80 ret = btrfs_dir_data_len(leaf, di);
83 btrfs_free_path(path);
87 int __btrfs_setxattr(struct inode *inode, const char *name,
88 const void *value, size_t size, int flags)
90 struct btrfs_dir_item *di;
91 struct btrfs_root *root = BTRFS_I(inode)->root;
92 struct btrfs_trans_handle *trans;
93 struct btrfs_path *path;
96 path = btrfs_alloc_path();
100 trans = btrfs_start_transaction(root, 1);
101 btrfs_set_trans_block_group(trans, inode);
103 /* first lets see if we already have this xattr */
104 di = btrfs_lookup_xattr(trans, root, path, inode->i_ino, name,
111 /* ok we already have this xattr, lets remove it */
113 /* if we want create only exit */
114 if (flags & XATTR_CREATE) {
119 ret = btrfs_delete_one_dir_name(trans, root, path, di);
122 btrfs_release_path(root, path);
124 /* if we don't have a value then we are removing the xattr */
130 btrfs_release_path(root, path);
132 if (flags & XATTR_REPLACE) {
133 /* we couldn't find the attr to replace */
139 /* ok we have to create a completely new xattr */
140 ret = btrfs_insert_xattr_item(trans, root, name, strlen(name),
141 value, size, inode->i_ino);
148 inode->i_ctime = CURRENT_TIME;
149 ret = btrfs_update_inode(trans, root, inode);
152 btrfs_end_transaction(trans, root);
153 btrfs_free_path(path);
157 ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
159 struct btrfs_key key, found_key;
160 struct inode *inode = dentry->d_inode;
161 struct btrfs_root *root = BTRFS_I(inode)->root;
162 struct btrfs_path *path;
163 struct btrfs_item *item;
164 struct extent_buffer *leaf;
165 struct btrfs_dir_item *di;
166 int ret = 0, slot, advance;
167 size_t total_size = 0, size_left = size;
168 unsigned long name_ptr;
173 * ok we want all objects associated with this id.
174 * NOTE: we set key.offset = 0; because we want to start with the
175 * first xattr that we find and walk forward
177 key.objectid = inode->i_ino;
178 btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
181 path = btrfs_alloc_path();
186 /* search for our xattrs */
187 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
192 leaf = path->nodes[0];
193 nritems = btrfs_header_nritems(leaf);
194 slot = path->slots[0];
196 /* this is where we start walking through the path */
197 if (advance || slot >= nritems) {
199 * if we've reached the last slot in this leaf we need
200 * to go to the next leaf and reset everything
202 if (slot >= nritems-1) {
203 ret = btrfs_next_leaf(root, path);
206 leaf = path->nodes[0];
207 nritems = btrfs_header_nritems(leaf);
208 slot = path->slots[0];
211 * just walking through the slots on this leaf
219 item = btrfs_item_nr(leaf, slot);
220 btrfs_item_key_to_cpu(leaf, &found_key, slot);
222 /* check to make sure this item is what we want */
223 if (found_key.objectid != key.objectid)
225 if (btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY)
228 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
230 name_len = btrfs_dir_name_len(leaf, di);
231 total_size += name_len + 1;
233 /* we are just looking for how big our buffer needs to be */
237 if (!buffer || (name_len + 1) > size_left) {
242 name_ptr = (unsigned long)(di + 1);
243 read_extent_buffer(leaf, buffer, name_ptr, name_len);
244 buffer[name_len] = '\0';
246 size_left -= name_len + 1;
247 buffer += name_len + 1;
252 btrfs_free_path(path);
258 * List of handlers for synthetic system.* attributes. All real ondisk
259 * attributes are handled directly.
261 struct xattr_handler *btrfs_xattr_handlers[] = {
262 #ifdef CONFIG_FS_POSIX_ACL
263 &btrfs_xattr_acl_access_handler,
264 &btrfs_xattr_acl_default_handler,
270 * Check if the attribute is in a supported namespace.
272 * This applied after the check for the synthetic attributes in the system
275 static bool btrfs_is_valid_xattr(const char *name)
277 return !strncmp(name, XATTR_SECURITY_PREFIX,
278 XATTR_SECURITY_PREFIX_LEN) ||
279 !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) ||
280 !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) ||
281 !strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN);
284 ssize_t btrfs_getxattr(struct dentry *dentry, const char *name,
285 void *buffer, size_t size)
288 * If this is a request for a synthetic attribute in the system.*
289 * namespace use the generic infrastructure to resolve a handler
290 * for it via sb->s_xattr.
292 if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
293 return generic_getxattr(dentry, name, buffer, size);
295 if (!btrfs_is_valid_xattr(name))
297 return __btrfs_getxattr(dentry->d_inode, name, buffer, size);
300 int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value,
301 size_t size, int flags)
304 * If this is a request for a synthetic attribute in the system.*
305 * namespace use the generic infrastructure to resolve a handler
306 * for it via sb->s_xattr.
308 if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
309 return generic_setxattr(dentry, name, value, size, flags);
311 if (!btrfs_is_valid_xattr(name))
315 value = ""; /* empty EA, do not remove */
316 return __btrfs_setxattr(dentry->d_inode, name, value, size, flags);
319 int btrfs_removexattr(struct dentry *dentry, const char *name)
322 * If this is a request for a synthetic attribute in the system.*
323 * namespace use the generic infrastructure to resolve a handler
324 * for it via sb->s_xattr.
326 if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
327 return generic_removexattr(dentry, name);
329 if (!btrfs_is_valid_xattr(name))
331 return __btrfs_setxattr(dentry->d_inode, name, NULL, 0, XATTR_REPLACE);