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"
34 ssize_t
__btrfs_getxattr(struct inode
*inode
, const char *name
,
35 void *buffer
, size_t size
)
37 struct btrfs_dir_item
*di
;
38 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
39 struct btrfs_path
*path
;
40 struct extent_buffer
*leaf
;
42 unsigned long data_ptr
;
44 path
= btrfs_alloc_path();
48 /* lookup the xattr by name */
49 di
= btrfs_lookup_xattr(NULL
, root
, path
, btrfs_ino(inode
), name
,
54 } else if (IS_ERR(di
)) {
59 leaf
= path
->nodes
[0];
60 /* if size is 0, that means we want the size of the attr */
62 ret
= btrfs_dir_data_len(leaf
, di
);
66 /* now get the data out of our dir_item */
67 if (btrfs_dir_data_len(leaf
, di
) > size
) {
73 * The way things are packed into the leaf is like this
74 * |struct btrfs_dir_item|name|data|
75 * where name is the xattr name, so security.foo, and data is the
76 * content of the xattr. data_ptr points to the location in memory
77 * where the data starts in the in memory leaf
79 data_ptr
= (unsigned long)((char *)(di
+ 1) +
80 btrfs_dir_name_len(leaf
, di
));
81 read_extent_buffer(leaf
, buffer
, data_ptr
,
82 btrfs_dir_data_len(leaf
, di
));
83 ret
= btrfs_dir_data_len(leaf
, di
);
86 btrfs_free_path(path
);
90 static int do_setxattr(struct btrfs_trans_handle
*trans
,
91 struct inode
*inode
, const char *name
,
92 const void *value
, size_t size
, int flags
)
94 struct btrfs_dir_item
*di
;
95 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
96 struct btrfs_path
*path
;
97 size_t name_len
= strlen(name
);
100 if (name_len
+ size
> BTRFS_MAX_XATTR_SIZE(root
))
103 path
= btrfs_alloc_path();
107 if (flags
& XATTR_REPLACE
) {
108 di
= btrfs_lookup_xattr(trans
, root
, path
, btrfs_ino(inode
), name
,
117 ret
= btrfs_delete_one_dir_name(trans
, root
, path
, di
);
120 btrfs_release_path(path
);
123 * remove the attribute
128 di
= btrfs_lookup_xattr(NULL
, root
, path
, btrfs_ino(inode
),
136 btrfs_release_path(path
);
140 ret
= btrfs_insert_xattr_item(trans
, root
, path
, btrfs_ino(inode
),
141 name
, name_len
, value
, size
);
143 * If we're setting an xattr to a new value but the new value is say
144 * exactly BTRFS_MAX_XATTR_SIZE, we could end up with EOVERFLOW getting
145 * back from split_leaf. This is because it thinks we'll be extending
146 * the existing item size, but we're asking for enough space to add the
147 * item itself. So if we get EOVERFLOW just set ret to EEXIST and let
148 * the rest of the function figure it out.
150 if (ret
== -EOVERFLOW
)
153 if (ret
== -EEXIST
) {
154 if (flags
& XATTR_CREATE
)
157 * We can't use the path we already have since we won't have the
158 * proper locking for a delete, so release the path and
159 * re-lookup to delete the thing.
161 btrfs_release_path(path
);
162 di
= btrfs_lookup_xattr(trans
, root
, path
, btrfs_ino(inode
),
168 /* Shouldn't happen but just in case... */
169 btrfs_release_path(path
);
173 ret
= btrfs_delete_one_dir_name(trans
, root
, path
, di
);
178 * We have a value to set, so go back and try to insert it now.
181 btrfs_release_path(path
);
186 btrfs_free_path(path
);
191 * @value: "" makes the attribute to empty, NULL removes it
193 int __btrfs_setxattr(struct btrfs_trans_handle
*trans
,
194 struct inode
*inode
, const char *name
,
195 const void *value
, size_t size
, int flags
)
197 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
201 return do_setxattr(trans
, inode
, name
, value
, size
, flags
);
203 trans
= btrfs_start_transaction(root
, 2);
205 return PTR_ERR(trans
);
207 ret
= do_setxattr(trans
, inode
, name
, value
, size
, flags
);
211 inode_inc_iversion(inode
);
212 inode
->i_ctime
= CURRENT_TIME
;
213 set_bit(BTRFS_INODE_COPY_EVERYTHING
, &BTRFS_I(inode
)->runtime_flags
);
214 ret
= btrfs_update_inode(trans
, root
, inode
);
217 btrfs_end_transaction(trans
, root
);
221 ssize_t
btrfs_listxattr(struct dentry
*dentry
, char *buffer
, size_t size
)
223 struct btrfs_key key
, found_key
;
224 struct inode
*inode
= dentry
->d_inode
;
225 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
226 struct btrfs_path
*path
;
227 struct extent_buffer
*leaf
;
228 struct btrfs_dir_item
*di
;
230 size_t total_size
= 0, size_left
= size
;
231 unsigned long name_ptr
;
235 * ok we want all objects associated with this id.
236 * NOTE: we set key.offset = 0; because we want to start with the
237 * first xattr that we find and walk forward
239 key
.objectid
= btrfs_ino(inode
);
240 key
.type
= BTRFS_XATTR_ITEM_KEY
;
243 path
= btrfs_alloc_path();
248 /* search for our xattrs */
249 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
254 leaf
= path
->nodes
[0];
255 slot
= path
->slots
[0];
257 /* this is where we start walking through the path */
258 if (slot
>= btrfs_header_nritems(leaf
)) {
260 * if we've reached the last slot in this leaf we need
261 * to go to the next leaf and reset everything
263 ret
= btrfs_next_leaf(root
, path
);
271 btrfs_item_key_to_cpu(leaf
, &found_key
, slot
);
273 /* check to make sure this item is what we want */
274 if (found_key
.objectid
!= key
.objectid
)
276 if (found_key
.type
!= BTRFS_XATTR_ITEM_KEY
)
279 di
= btrfs_item_ptr(leaf
, slot
, struct btrfs_dir_item
);
280 if (verify_dir_item(root
, leaf
, di
))
283 name_len
= btrfs_dir_name_len(leaf
, di
);
284 total_size
+= name_len
+ 1;
286 /* we are just looking for how big our buffer needs to be */
290 if (!buffer
|| (name_len
+ 1) > size_left
) {
295 name_ptr
= (unsigned long)(di
+ 1);
296 read_extent_buffer(leaf
, buffer
, name_ptr
, name_len
);
297 buffer
[name_len
] = '\0';
299 size_left
-= name_len
+ 1;
300 buffer
+= name_len
+ 1;
307 btrfs_free_path(path
);
313 * List of handlers for synthetic system.* attributes. All real ondisk
314 * attributes are handled directly.
316 const struct xattr_handler
*btrfs_xattr_handlers
[] = {
317 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
318 &posix_acl_access_xattr_handler
,
319 &posix_acl_default_xattr_handler
,
325 * Check if the attribute is in a supported namespace.
327 * This applied after the check for the synthetic attributes in the system
330 static bool btrfs_is_valid_xattr(const char *name
)
332 return !strncmp(name
, XATTR_SECURITY_PREFIX
,
333 XATTR_SECURITY_PREFIX_LEN
) ||
334 !strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
) ||
335 !strncmp(name
, XATTR_TRUSTED_PREFIX
, XATTR_TRUSTED_PREFIX_LEN
) ||
336 !strncmp(name
, XATTR_USER_PREFIX
, XATTR_USER_PREFIX_LEN
) ||
337 !strncmp(name
, XATTR_BTRFS_PREFIX
, XATTR_BTRFS_PREFIX_LEN
);
340 ssize_t
btrfs_getxattr(struct dentry
*dentry
, const char *name
,
341 void *buffer
, size_t size
)
344 * If this is a request for a synthetic attribute in the system.*
345 * namespace use the generic infrastructure to resolve a handler
346 * for it via sb->s_xattr.
348 if (!strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
))
349 return generic_getxattr(dentry
, name
, buffer
, size
);
351 if (!btrfs_is_valid_xattr(name
))
353 return __btrfs_getxattr(dentry
->d_inode
, name
, buffer
, size
);
356 int btrfs_setxattr(struct dentry
*dentry
, const char *name
, const void *value
,
357 size_t size
, int flags
)
359 struct btrfs_root
*root
= BTRFS_I(dentry
->d_inode
)->root
;
362 * The permission on security.* and system.* is not checked
365 if (btrfs_root_readonly(root
))
369 * If this is a request for a synthetic attribute in the system.*
370 * namespace use the generic infrastructure to resolve a handler
371 * for it via sb->s_xattr.
373 if (!strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
))
374 return generic_setxattr(dentry
, name
, value
, size
, flags
);
376 if (!btrfs_is_valid_xattr(name
))
379 if (!strncmp(name
, XATTR_BTRFS_PREFIX
, XATTR_BTRFS_PREFIX_LEN
))
380 return btrfs_set_prop(dentry
->d_inode
, name
,
384 value
= ""; /* empty EA, do not remove */
386 return __btrfs_setxattr(NULL
, dentry
->d_inode
, name
, value
, size
,
390 int btrfs_removexattr(struct dentry
*dentry
, const char *name
)
392 struct btrfs_root
*root
= BTRFS_I(dentry
->d_inode
)->root
;
395 * The permission on security.* and system.* is not checked
398 if (btrfs_root_readonly(root
))
402 * If this is a request for a synthetic attribute in the system.*
403 * namespace use the generic infrastructure to resolve a handler
404 * for it via sb->s_xattr.
406 if (!strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
))
407 return generic_removexattr(dentry
, name
);
409 if (!btrfs_is_valid_xattr(name
))
412 if (!strncmp(name
, XATTR_BTRFS_PREFIX
, XATTR_BTRFS_PREFIX_LEN
))
413 return btrfs_set_prop(dentry
->d_inode
, name
,
414 NULL
, 0, XATTR_REPLACE
);
416 return __btrfs_setxattr(NULL
, dentry
->d_inode
, name
, NULL
, 0,
420 static int btrfs_initxattrs(struct inode
*inode
,
421 const struct xattr
*xattr_array
, void *fs_info
)
423 const struct xattr
*xattr
;
424 struct btrfs_trans_handle
*trans
= fs_info
;
428 for (xattr
= xattr_array
; xattr
->name
!= NULL
; xattr
++) {
429 name
= kmalloc(XATTR_SECURITY_PREFIX_LEN
+
430 strlen(xattr
->name
) + 1, GFP_NOFS
);
435 strcpy(name
, XATTR_SECURITY_PREFIX
);
436 strcpy(name
+ XATTR_SECURITY_PREFIX_LEN
, xattr
->name
);
437 err
= __btrfs_setxattr(trans
, inode
, name
,
438 xattr
->value
, xattr
->value_len
, 0);
446 int btrfs_xattr_security_init(struct btrfs_trans_handle
*trans
,
447 struct inode
*inode
, struct inode
*dir
,
448 const struct qstr
*qstr
)
450 return security_inode_init_security(inode
, dir
, qstr
,
451 &btrfs_initxattrs
, trans
);