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"
33 ssize_t
__btrfs_getxattr(struct inode
*inode
, const char *name
,
34 void *buffer
, size_t size
)
36 struct btrfs_dir_item
*di
;
37 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
38 struct btrfs_path
*path
;
39 struct extent_buffer
*leaf
;
41 unsigned long data_ptr
;
43 path
= btrfs_alloc_path();
47 /* lookup the xattr by name */
48 di
= btrfs_lookup_xattr(NULL
, root
, path
, btrfs_ino(inode
), name
,
53 } else if (IS_ERR(di
)) {
58 leaf
= path
->nodes
[0];
59 /* if size is 0, that means we want the size of the attr */
61 ret
= btrfs_dir_data_len(leaf
, di
);
65 /* now get the data out of our dir_item */
66 if (btrfs_dir_data_len(leaf
, di
) > size
) {
72 * The way things are packed into the leaf is like this
73 * |struct btrfs_dir_item|name|data|
74 * where name is the xattr name, so security.foo, and data is the
75 * content of the xattr. data_ptr points to the location in memory
76 * where the data starts in the in memory leaf
78 data_ptr
= (unsigned long)((char *)(di
+ 1) +
79 btrfs_dir_name_len(leaf
, di
));
80 read_extent_buffer(leaf
, buffer
, data_ptr
,
81 btrfs_dir_data_len(leaf
, di
));
82 ret
= btrfs_dir_data_len(leaf
, di
);
85 btrfs_free_path(path
);
89 static int do_setxattr(struct btrfs_trans_handle
*trans
,
90 struct inode
*inode
, const char *name
,
91 const void *value
, size_t size
, int flags
)
93 struct btrfs_dir_item
*di
;
94 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
95 struct btrfs_path
*path
;
96 size_t name_len
= strlen(name
);
99 if (name_len
+ size
> BTRFS_MAX_XATTR_SIZE(root
))
102 path
= btrfs_alloc_path();
106 if (flags
& XATTR_REPLACE
) {
107 di
= btrfs_lookup_xattr(trans
, root
, path
, btrfs_ino(inode
), name
,
116 ret
= btrfs_delete_one_dir_name(trans
, root
, path
, di
);
119 btrfs_release_path(path
);
122 * remove the attribute
127 di
= btrfs_lookup_xattr(NULL
, root
, path
, btrfs_ino(inode
),
135 btrfs_release_path(path
);
139 ret
= btrfs_insert_xattr_item(trans
, root
, path
, btrfs_ino(inode
),
140 name
, name_len
, value
, size
);
142 * If we're setting an xattr to a new value but the new value is say
143 * exactly BTRFS_MAX_XATTR_SIZE, we could end up with EOVERFLOW getting
144 * back from split_leaf. This is because it thinks we'll be extending
145 * the existing item size, but we're asking for enough space to add the
146 * item itself. So if we get EOVERFLOW just set ret to EEXIST and let
147 * the rest of the function figure it out.
149 if (ret
== -EOVERFLOW
)
152 if (ret
== -EEXIST
) {
153 if (flags
& XATTR_CREATE
)
156 * We can't use the path we already have since we won't have the
157 * proper locking for a delete, so release the path and
158 * re-lookup to delete the thing.
160 btrfs_release_path(path
);
161 di
= btrfs_lookup_xattr(trans
, root
, path
, btrfs_ino(inode
),
167 /* Shouldn't happen but just in case... */
168 btrfs_release_path(path
);
172 ret
= btrfs_delete_one_dir_name(trans
, root
, path
, di
);
177 * We have a value to set, so go back and try to insert it now.
180 btrfs_release_path(path
);
185 btrfs_free_path(path
);
190 * @value: "" makes the attribute to empty, NULL removes it
192 int __btrfs_setxattr(struct btrfs_trans_handle
*trans
,
193 struct inode
*inode
, const char *name
,
194 const void *value
, size_t size
, int flags
)
196 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
200 return do_setxattr(trans
, inode
, name
, value
, size
, flags
);
202 trans
= btrfs_start_transaction(root
, 2);
204 return PTR_ERR(trans
);
206 ret
= do_setxattr(trans
, inode
, name
, value
, size
, flags
);
210 inode_inc_iversion(inode
);
211 inode
->i_ctime
= CURRENT_TIME
;
212 set_bit(BTRFS_INODE_COPY_EVERYTHING
, &BTRFS_I(inode
)->runtime_flags
);
213 ret
= btrfs_update_inode(trans
, root
, inode
);
216 btrfs_end_transaction(trans
, root
);
220 ssize_t
btrfs_listxattr(struct dentry
*dentry
, char *buffer
, size_t size
)
222 struct btrfs_key key
, found_key
;
223 struct inode
*inode
= dentry
->d_inode
;
224 struct btrfs_root
*root
= BTRFS_I(inode
)->root
;
225 struct btrfs_path
*path
;
226 struct extent_buffer
*leaf
;
227 struct btrfs_dir_item
*di
;
229 size_t total_size
= 0, size_left
= size
;
230 unsigned long name_ptr
;
234 * ok we want all objects associated with this id.
235 * NOTE: we set key.offset = 0; because we want to start with the
236 * first xattr that we find and walk forward
238 key
.objectid
= btrfs_ino(inode
);
239 btrfs_set_key_type(&key
, BTRFS_XATTR_ITEM_KEY
);
242 path
= btrfs_alloc_path();
247 /* search for our xattrs */
248 ret
= btrfs_search_slot(NULL
, root
, &key
, path
, 0, 0);
253 leaf
= path
->nodes
[0];
254 slot
= path
->slots
[0];
256 /* this is where we start walking through the path */
257 if (slot
>= btrfs_header_nritems(leaf
)) {
259 * if we've reached the last slot in this leaf we need
260 * to go to the next leaf and reset everything
262 ret
= btrfs_next_leaf(root
, path
);
270 btrfs_item_key_to_cpu(leaf
, &found_key
, slot
);
272 /* check to make sure this item is what we want */
273 if (found_key
.objectid
!= key
.objectid
)
275 if (btrfs_key_type(&found_key
) != BTRFS_XATTR_ITEM_KEY
)
278 di
= btrfs_item_ptr(leaf
, slot
, struct btrfs_dir_item
);
279 if (verify_dir_item(root
, leaf
, di
))
282 name_len
= btrfs_dir_name_len(leaf
, di
);
283 total_size
+= name_len
+ 1;
285 /* we are just looking for how big our buffer needs to be */
289 if (!buffer
|| (name_len
+ 1) > size_left
) {
294 name_ptr
= (unsigned long)(di
+ 1);
295 read_extent_buffer(leaf
, buffer
, name_ptr
, name_len
);
296 buffer
[name_len
] = '\0';
298 size_left
-= name_len
+ 1;
299 buffer
+= name_len
+ 1;
306 btrfs_free_path(path
);
312 * List of handlers for synthetic system.* attributes. All real ondisk
313 * attributes are handled directly.
315 const struct xattr_handler
*btrfs_xattr_handlers
[] = {
316 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
317 &btrfs_xattr_acl_access_handler
,
318 &btrfs_xattr_acl_default_handler
,
324 * Check if the attribute is in a supported namespace.
326 * This applied after the check for the synthetic attributes in the system
329 static bool btrfs_is_valid_xattr(const char *name
)
331 return !strncmp(name
, XATTR_SECURITY_PREFIX
,
332 XATTR_SECURITY_PREFIX_LEN
) ||
333 !strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
) ||
334 !strncmp(name
, XATTR_TRUSTED_PREFIX
, XATTR_TRUSTED_PREFIX_LEN
) ||
335 !strncmp(name
, XATTR_USER_PREFIX
, XATTR_USER_PREFIX_LEN
) ||
336 !strncmp(name
, XATTR_BTRFS_PREFIX
, XATTR_BTRFS_PREFIX_LEN
);
339 ssize_t
btrfs_getxattr(struct dentry
*dentry
, const char *name
,
340 void *buffer
, size_t size
)
343 * If this is a request for a synthetic attribute in the system.*
344 * namespace use the generic infrastructure to resolve a handler
345 * for it via sb->s_xattr.
347 if (!strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
))
348 return generic_getxattr(dentry
, name
, buffer
, size
);
350 if (!btrfs_is_valid_xattr(name
))
352 return __btrfs_getxattr(dentry
->d_inode
, name
, buffer
, size
);
355 int btrfs_setxattr(struct dentry
*dentry
, const char *name
, const void *value
,
356 size_t size
, int flags
)
358 struct btrfs_root
*root
= BTRFS_I(dentry
->d_inode
)->root
;
361 * The permission on security.* and system.* is not checked
364 if (btrfs_root_readonly(root
))
368 * If this is a request for a synthetic attribute in the system.*
369 * namespace use the generic infrastructure to resolve a handler
370 * for it via sb->s_xattr.
372 if (!strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
))
373 return generic_setxattr(dentry
, name
, value
, size
, flags
);
375 if (!btrfs_is_valid_xattr(name
))
378 if (!strncmp(name
, XATTR_BTRFS_PREFIX
, XATTR_BTRFS_PREFIX_LEN
))
379 return btrfs_set_prop(dentry
->d_inode
, name
,
383 value
= ""; /* empty EA, do not remove */
385 return __btrfs_setxattr(NULL
, dentry
->d_inode
, name
, value
, size
,
389 int btrfs_removexattr(struct dentry
*dentry
, const char *name
)
391 struct btrfs_root
*root
= BTRFS_I(dentry
->d_inode
)->root
;
394 * The permission on security.* and system.* is not checked
397 if (btrfs_root_readonly(root
))
401 * If this is a request for a synthetic attribute in the system.*
402 * namespace use the generic infrastructure to resolve a handler
403 * for it via sb->s_xattr.
405 if (!strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
))
406 return generic_removexattr(dentry
, name
);
408 if (!btrfs_is_valid_xattr(name
))
411 if (!strncmp(name
, XATTR_BTRFS_PREFIX
, XATTR_BTRFS_PREFIX_LEN
))
412 return btrfs_set_prop(dentry
->d_inode
, name
,
413 NULL
, 0, XATTR_REPLACE
);
415 return __btrfs_setxattr(NULL
, dentry
->d_inode
, name
, NULL
, 0,
419 static int btrfs_initxattrs(struct inode
*inode
,
420 const struct xattr
*xattr_array
, void *fs_info
)
422 const struct xattr
*xattr
;
423 struct btrfs_trans_handle
*trans
= fs_info
;
427 for (xattr
= xattr_array
; xattr
->name
!= NULL
; xattr
++) {
428 name
= kmalloc(XATTR_SECURITY_PREFIX_LEN
+
429 strlen(xattr
->name
) + 1, GFP_NOFS
);
434 strcpy(name
, XATTR_SECURITY_PREFIX
);
435 strcpy(name
+ XATTR_SECURITY_PREFIX_LEN
, xattr
->name
);
436 err
= __btrfs_setxattr(trans
, inode
, name
,
437 xattr
->value
, xattr
->value_len
, 0);
445 int btrfs_xattr_security_init(struct btrfs_trans_handle
*trans
,
446 struct inode
*inode
, struct inode
*dir
,
447 const struct qstr
*qstr
)
449 return security_inode_init_security(inode
, dir
, qstr
,
450 &btrfs_initxattrs
, trans
);