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
126 di
= btrfs_lookup_xattr(NULL
, root
, path
, btrfs_ino(inode
),
134 btrfs_release_path(path
);
138 ret
= btrfs_insert_xattr_item(trans
, root
, path
, btrfs_ino(inode
),
139 name
, name_len
, value
, size
);
141 * If we're setting an xattr to a new value but the new value is say
142 * exactly BTRFS_MAX_XATTR_SIZE, we could end up with EOVERFLOW getting
143 * back from split_leaf. This is because it thinks we'll be extending
144 * the existing item size, but we're asking for enough space to add the
145 * item itself. So if we get EOVERFLOW just set ret to EEXIST and let
146 * the rest of the function figure it out.
148 if (ret
== -EOVERFLOW
)
151 if (ret
== -EEXIST
) {
152 if (flags
& XATTR_CREATE
)
155 * We can't use the path we already have since we won't have the
156 * proper locking for a delete, so release the path and
157 * re-lookup to delete the thing.
159 btrfs_release_path(path
);
160 di
= btrfs_lookup_xattr(trans
, root
, path
, btrfs_ino(inode
),
166 /* Shouldn't happen but just in case... */
167 btrfs_release_path(path
);
171 ret
= btrfs_delete_one_dir_name(trans
, root
, path
, di
);
176 * We have a value to set, so go back and try to insert it now.
179 btrfs_release_path(path
);
184 btrfs_free_path(path
);
189 * @value: "" makes the attribute to empty, NULL removes it
191 int __btrfs_setxattr(struct btrfs_trans_handle
*trans
,
192 struct inode
*inode
, const char *name
,
193 const void *value
, size_t size
, int flags
)
195 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
199 return do_setxattr(trans
, inode
, name
, value
, size
, flags
);
201 trans
= btrfs_start_transaction(root
, 2);
203 return PTR_ERR(trans
);
205 ret
= do_setxattr(trans
, inode
, name
, value
, size
, flags
);
209 inode_inc_iversion(inode
);
210 inode
->i_ctime
= CURRENT_TIME
;
211 ret
= btrfs_update_inode(trans
, root
, inode
);
214 btrfs_end_transaction(trans
, root
);
218 ssize_t
btrfs_listxattr(struct dentry
*dentry
, char *buffer
, size_t size
)
220 struct btrfs_key key
, found_key
;
221 struct inode
*inode
= dentry
->d_inode
;
222 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
223 struct btrfs_path
*path
;
224 struct extent_buffer
*leaf
;
225 struct btrfs_dir_item
*di
;
227 size_t total_size
= 0, size_left
= size
;
228 unsigned long name_ptr
;
232 * ok we want all objects associated with this id.
233 * NOTE: we set key.offset = 0; because we want to start with the
234 * first xattr that we find and walk forward
236 key
.objectid
= btrfs_ino(inode
);
237 btrfs_set_key_type(&key
, BTRFS_XATTR_ITEM_KEY
);
240 path
= btrfs_alloc_path();
245 /* search for our xattrs */
246 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
251 leaf
= path
->nodes
[0];
252 slot
= path
->slots
[0];
254 /* this is where we start walking through the path */
255 if (slot
>= btrfs_header_nritems(leaf
)) {
257 * if we've reached the last slot in this leaf we need
258 * to go to the next leaf and reset everything
260 ret
= btrfs_next_leaf(root
, path
);
268 btrfs_item_key_to_cpu(leaf
, &found_key
, slot
);
270 /* check to make sure this item is what we want */
271 if (found_key
.objectid
!= key
.objectid
)
273 if (btrfs_key_type(&found_key
) != BTRFS_XATTR_ITEM_KEY
)
276 di
= btrfs_item_ptr(leaf
, slot
, struct btrfs_dir_item
);
277 if (verify_dir_item(root
, leaf
, di
))
280 name_len
= btrfs_dir_name_len(leaf
, di
);
281 total_size
+= name_len
+ 1;
283 /* we are just looking for how big our buffer needs to be */
287 if (!buffer
|| (name_len
+ 1) > size_left
) {
292 name_ptr
= (unsigned long)(di
+ 1);
293 read_extent_buffer(leaf
, buffer
, name_ptr
, name_len
);
294 buffer
[name_len
] = '\0';
296 size_left
-= name_len
+ 1;
297 buffer
+= name_len
+ 1;
304 btrfs_free_path(path
);
310 * List of handlers for synthetic system.* attributes. All real ondisk
311 * attributes are handled directly.
313 const struct xattr_handler
*btrfs_xattr_handlers
[] = {
314 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
315 &btrfs_xattr_acl_access_handler
,
316 &btrfs_xattr_acl_default_handler
,
322 * Check if the attribute is in a supported namespace.
324 * This applied after the check for the synthetic attributes in the system
327 static bool btrfs_is_valid_xattr(const char *name
)
329 return !strncmp(name
, XATTR_SECURITY_PREFIX
,
330 XATTR_SECURITY_PREFIX_LEN
) ||
331 !strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
) ||
332 !strncmp(name
, XATTR_TRUSTED_PREFIX
, XATTR_TRUSTED_PREFIX_LEN
) ||
333 !strncmp(name
, XATTR_USER_PREFIX
, XATTR_USER_PREFIX_LEN
);
336 ssize_t
btrfs_getxattr(struct dentry
*dentry
, const char *name
,
337 void *buffer
, size_t size
)
340 * If this is a request for a synthetic attribute in the system.*
341 * namespace use the generic infrastructure to resolve a handler
342 * for it via sb->s_xattr.
344 if (!strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
))
345 return generic_getxattr(dentry
, name
, buffer
, size
);
347 if (!btrfs_is_valid_xattr(name
))
349 return __btrfs_getxattr(dentry
->d_inode
, name
, buffer
, size
);
352 int btrfs_setxattr(struct dentry
*dentry
, const char *name
, const void *value
,
353 size_t size
, int flags
)
355 struct btrfs_root
*root
= BTRFS_I(dentry
->d_inode
)->root
;
358 * The permission on security.* and system.* is not checked
361 if (btrfs_root_readonly(root
))
365 * If this is a request for a synthetic attribute in the system.*
366 * namespace use the generic infrastructure to resolve a handler
367 * for it via sb->s_xattr.
369 if (!strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
))
370 return generic_setxattr(dentry
, name
, value
, size
, flags
);
372 if (!btrfs_is_valid_xattr(name
))
376 value
= ""; /* empty EA, do not remove */
378 return __btrfs_setxattr(NULL
, dentry
->d_inode
, name
, value
, size
,
382 int btrfs_removexattr(struct dentry
*dentry
, const char *name
)
384 struct btrfs_root
*root
= BTRFS_I(dentry
->d_inode
)->root
;
387 * The permission on security.* and system.* is not checked
390 if (btrfs_root_readonly(root
))
394 * If this is a request for a synthetic attribute in the system.*
395 * namespace use the generic infrastructure to resolve a handler
396 * for it via sb->s_xattr.
398 if (!strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
))
399 return generic_removexattr(dentry
, name
);
401 if (!btrfs_is_valid_xattr(name
))
404 return __btrfs_setxattr(NULL
, dentry
->d_inode
, name
, NULL
, 0,
408 int btrfs_initxattrs(struct inode
*inode
, const struct xattr
*xattr_array
,
411 const struct xattr
*xattr
;
412 struct btrfs_trans_handle
*trans
= fs_info
;
416 for (xattr
= xattr_array
; xattr
->name
!= NULL
; xattr
++) {
417 name
= kmalloc(XATTR_SECURITY_PREFIX_LEN
+
418 strlen(xattr
->name
) + 1, GFP_NOFS
);
423 strcpy(name
, XATTR_SECURITY_PREFIX
);
424 strcpy(name
+ XATTR_SECURITY_PREFIX_LEN
, xattr
->name
);
425 err
= __btrfs_setxattr(trans
, inode
, name
,
426 xattr
->value
, xattr
->value_len
, 0);
434 int btrfs_xattr_security_init(struct btrfs_trans_handle
*trans
,
435 struct inode
*inode
, struct inode
*dir
,
436 const struct qstr
*qstr
)
438 return security_inode_init_security(inode
, dir
, qstr
,
439 &btrfs_initxattrs
, trans
);