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>
26 #include "btrfs_inode.h"
27 #include "transaction.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
;
40 unsigned long data_ptr
;
42 path
= btrfs_alloc_path();
46 /* lookup the xattr by name */
47 di
= btrfs_lookup_xattr(NULL
, root
, path
, btrfs_ino(inode
), name
,
52 } else if (IS_ERR(di
)) {
57 leaf
= path
->nodes
[0];
58 /* if size is 0, that means we want the size of the attr */
60 ret
= btrfs_dir_data_len(leaf
, di
);
64 /* now get the data out of our dir_item */
65 if (btrfs_dir_data_len(leaf
, di
) > size
) {
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
);
84 btrfs_free_path(path
);
88 static int do_setxattr(struct btrfs_trans_handle
*trans
,
89 struct inode
*inode
, const char *name
,
90 const void *value
, size_t size
, int flags
)
92 struct btrfs_dir_item
*di
;
93 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
94 struct btrfs_path
*path
;
95 size_t name_len
= strlen(name
);
98 if (name_len
+ size
> BTRFS_MAX_XATTR_SIZE(root
))
101 path
= btrfs_alloc_path();
105 if (flags
& XATTR_REPLACE
) {
106 di
= btrfs_lookup_xattr(trans
, root
, path
, btrfs_ino(inode
), name
,
115 ret
= btrfs_delete_one_dir_name(trans
, root
, path
, di
);
118 btrfs_release_path(path
);
121 * remove the attribute
128 ret
= btrfs_insert_xattr_item(trans
, root
, path
, btrfs_ino(inode
),
129 name
, name_len
, value
, size
);
131 * If we're setting an xattr to a new value but the new value is say
132 * exactly BTRFS_MAX_XATTR_SIZE, we could end up with EOVERFLOW getting
133 * back from split_leaf. This is because it thinks we'll be extending
134 * the existing item size, but we're asking for enough space to add the
135 * item itself. So if we get EOVERFLOW just set ret to EEXIST and let
136 * the rest of the function figure it out.
138 if (ret
== -EOVERFLOW
)
141 if (ret
== -EEXIST
) {
142 if (flags
& XATTR_CREATE
)
145 * We can't use the path we already have since we won't have the
146 * proper locking for a delete, so release the path and
147 * re-lookup to delete the thing.
149 btrfs_release_path(path
);
150 di
= btrfs_lookup_xattr(trans
, root
, path
, btrfs_ino(inode
),
156 /* Shouldn't happen but just in case... */
157 btrfs_release_path(path
);
161 ret
= btrfs_delete_one_dir_name(trans
, root
, path
, di
);
166 * We have a value to set, so go back and try to insert it now.
169 btrfs_release_path(path
);
174 btrfs_free_path(path
);
179 * @value: "" makes the attribute to empty, NULL removes it
181 int __btrfs_setxattr(struct btrfs_trans_handle
*trans
,
182 struct inode
*inode
, const char *name
,
183 const void *value
, size_t size
, int flags
)
185 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
189 return do_setxattr(trans
, inode
, name
, value
, size
, flags
);
191 trans
= btrfs_start_transaction(root
, 2);
193 return PTR_ERR(trans
);
195 ret
= do_setxattr(trans
, inode
, name
, value
, size
, flags
);
199 inode
->i_ctime
= CURRENT_TIME
;
200 ret
= btrfs_update_inode(trans
, root
, inode
);
203 btrfs_end_transaction_throttle(trans
, root
);
207 ssize_t
btrfs_listxattr(struct dentry
*dentry
, char *buffer
, size_t size
)
209 struct btrfs_key key
, found_key
;
210 struct inode
*inode
= dentry
->d_inode
;
211 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
212 struct btrfs_path
*path
;
213 struct extent_buffer
*leaf
;
214 struct btrfs_dir_item
*di
;
216 size_t total_size
= 0, size_left
= size
;
217 unsigned long name_ptr
;
221 * ok we want all objects associated with this id.
222 * NOTE: we set key.offset = 0; because we want to start with the
223 * first xattr that we find and walk forward
225 key
.objectid
= btrfs_ino(inode
);
226 btrfs_set_key_type(&key
, BTRFS_XATTR_ITEM_KEY
);
229 path
= btrfs_alloc_path();
234 /* search for our xattrs */
235 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
240 leaf
= path
->nodes
[0];
241 slot
= path
->slots
[0];
243 /* this is where we start walking through the path */
244 if (slot
>= btrfs_header_nritems(leaf
)) {
246 * if we've reached the last slot in this leaf we need
247 * to go to the next leaf and reset everything
249 ret
= btrfs_next_leaf(root
, path
);
257 btrfs_item_key_to_cpu(leaf
, &found_key
, slot
);
259 /* check to make sure this item is what we want */
260 if (found_key
.objectid
!= key
.objectid
)
262 if (btrfs_key_type(&found_key
) != BTRFS_XATTR_ITEM_KEY
)
265 di
= btrfs_item_ptr(leaf
, slot
, struct btrfs_dir_item
);
266 if (verify_dir_item(root
, leaf
, di
))
269 name_len
= btrfs_dir_name_len(leaf
, di
);
270 total_size
+= name_len
+ 1;
272 /* we are just looking for how big our buffer needs to be */
276 if (!buffer
|| (name_len
+ 1) > size_left
) {
281 name_ptr
= (unsigned long)(di
+ 1);
282 read_extent_buffer(leaf
, buffer
, name_ptr
, name_len
);
283 buffer
[name_len
] = '\0';
285 size_left
-= name_len
+ 1;
286 buffer
+= name_len
+ 1;
293 btrfs_free_path(path
);
299 * List of handlers for synthetic system.* attributes. All real ondisk
300 * attributes are handled directly.
302 const struct xattr_handler
*btrfs_xattr_handlers
[] = {
303 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
304 &btrfs_xattr_acl_access_handler
,
305 &btrfs_xattr_acl_default_handler
,
311 * Check if the attribute is in a supported namespace.
313 * This applied after the check for the synthetic attributes in the system
316 static bool btrfs_is_valid_xattr(const char *name
)
318 return !strncmp(name
, XATTR_SECURITY_PREFIX
,
319 XATTR_SECURITY_PREFIX_LEN
) ||
320 !strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
) ||
321 !strncmp(name
, XATTR_TRUSTED_PREFIX
, XATTR_TRUSTED_PREFIX_LEN
) ||
322 !strncmp(name
, XATTR_USER_PREFIX
, XATTR_USER_PREFIX_LEN
);
325 ssize_t
btrfs_getxattr(struct dentry
*dentry
, const char *name
,
326 void *buffer
, size_t size
)
329 * If this is a request for a synthetic attribute in the system.*
330 * namespace use the generic infrastructure to resolve a handler
331 * for it via sb->s_xattr.
333 if (!strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
))
334 return generic_getxattr(dentry
, name
, buffer
, size
);
336 if (!btrfs_is_valid_xattr(name
))
338 return __btrfs_getxattr(dentry
->d_inode
, name
, buffer
, size
);
341 int btrfs_setxattr(struct dentry
*dentry
, const char *name
, const void *value
,
342 size_t size
, int flags
)
344 struct btrfs_root
*root
= BTRFS_I(dentry
->d_inode
)->root
;
347 * The permission on security.* and system.* is not checked
350 if (btrfs_root_readonly(root
))
354 * If this is a request for a synthetic attribute in the system.*
355 * namespace use the generic infrastructure to resolve a handler
356 * for it via sb->s_xattr.
358 if (!strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
))
359 return generic_setxattr(dentry
, name
, value
, size
, flags
);
361 if (!btrfs_is_valid_xattr(name
))
365 value
= ""; /* empty EA, do not remove */
367 return __btrfs_setxattr(NULL
, dentry
->d_inode
, name
, value
, size
,
371 int btrfs_removexattr(struct dentry
*dentry
, const char *name
)
373 struct btrfs_root
*root
= BTRFS_I(dentry
->d_inode
)->root
;
376 * The permission on security.* and system.* is not checked
379 if (btrfs_root_readonly(root
))
383 * If this is a request for a synthetic attribute in the system.*
384 * namespace use the generic infrastructure to resolve a handler
385 * for it via sb->s_xattr.
387 if (!strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
))
388 return generic_removexattr(dentry
, name
);
390 if (!btrfs_is_valid_xattr(name
))
393 return __btrfs_setxattr(NULL
, dentry
->d_inode
, name
, NULL
, 0,
397 int btrfs_initxattrs(struct inode
*inode
, const struct xattr
*xattr_array
,
400 const struct xattr
*xattr
;
401 struct btrfs_trans_handle
*trans
= fs_info
;
405 for (xattr
= xattr_array
; xattr
->name
!= NULL
; xattr
++) {
406 name
= kmalloc(XATTR_SECURITY_PREFIX_LEN
+
407 strlen(xattr
->name
) + 1, GFP_NOFS
);
412 strcpy(name
, XATTR_SECURITY_PREFIX
);
413 strcpy(name
+ XATTR_SECURITY_PREFIX_LEN
, xattr
->name
);
414 err
= __btrfs_setxattr(trans
, inode
, name
,
415 xattr
->value
, xattr
->value_len
, 0);
423 int btrfs_xattr_security_init(struct btrfs_trans_handle
*trans
,
424 struct inode
*inode
, struct inode
*dir
,
425 const struct qstr
*qstr
)
427 return security_inode_init_security(inode
, dir
, qstr
,
428 &btrfs_initxattrs
, trans
);