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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2007 Oracle. All rights reserved.
4 */
5
6#include "messages.h"
7#include "ctree.h"
8#include "disk-io.h"
9#include "transaction.h"
10#include "accessors.h"
11#include "dir-item.h"
12
13/*
14 * insert a name into a directory, doing overflow properly if there is a hash
15 * collision. data_size indicates how big the item inserted should be. On
16 * success a struct btrfs_dir_item pointer is returned, otherwise it is
17 * an ERR_PTR.
18 *
19 * The name is not copied into the dir item, you have to do that yourself.
20 */
21static struct btrfs_dir_item *insert_with_overflow(struct btrfs_trans_handle
22 *trans,
23 struct btrfs_root *root,
24 struct btrfs_path *path,
25 struct btrfs_key *cpu_key,
26 u32 data_size,
27 const char *name,
28 int name_len)
29{
30 struct btrfs_fs_info *fs_info = root->fs_info;
31 int ret;
32 char *ptr;
33 struct extent_buffer *leaf;
34
35 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
36 if (ret == -EEXIST) {
37 struct btrfs_dir_item *di;
38 di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
39 if (di)
40 return ERR_PTR(-EEXIST);
41 btrfs_extend_item(trans, path, data_size);
42 } else if (ret < 0)
43 return ERR_PTR(ret);
44 WARN_ON(ret > 0);
45 leaf = path->nodes[0];
46 ptr = btrfs_item_ptr(leaf, path->slots[0], char);
47 ASSERT(data_size <= btrfs_item_size(leaf, path->slots[0]));
48 ptr += btrfs_item_size(leaf, path->slots[0]) - data_size;
49 return (struct btrfs_dir_item *)ptr;
50}
51
52/*
53 * xattrs work a lot like directories, this inserts an xattr item
54 * into the tree
55 */
56int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,
57 struct btrfs_root *root,
58 struct btrfs_path *path, u64 objectid,
59 const char *name, u16 name_len,
60 const void *data, u16 data_len)
61{
62 int ret = 0;
63 struct btrfs_dir_item *dir_item;
64 unsigned long name_ptr, data_ptr;
65 struct btrfs_key key, location;
66 struct btrfs_disk_key disk_key;
67 struct extent_buffer *leaf;
68 u32 data_size;
69
70 if (name_len + data_len > BTRFS_MAX_XATTR_SIZE(root->fs_info))
71 return -ENOSPC;
72
73 key.objectid = objectid;
74 key.type = BTRFS_XATTR_ITEM_KEY;
75 key.offset = btrfs_name_hash(name, name_len);
76
77 data_size = sizeof(*dir_item) + name_len + data_len;
78 dir_item = insert_with_overflow(trans, root, path, &key, data_size,
79 name, name_len);
80 if (IS_ERR(dir_item))
81 return PTR_ERR(dir_item);
82 memset(&location, 0, sizeof(location));
83
84 leaf = path->nodes[0];
85 btrfs_cpu_key_to_disk(&disk_key, &location);
86 btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
87 btrfs_set_dir_flags(leaf, dir_item, BTRFS_FT_XATTR);
88 btrfs_set_dir_name_len(leaf, dir_item, name_len);
89 btrfs_set_dir_transid(leaf, dir_item, trans->transid);
90 btrfs_set_dir_data_len(leaf, dir_item, data_len);
91 name_ptr = (unsigned long)(dir_item + 1);
92 data_ptr = (unsigned long)((char *)name_ptr + name_len);
93
94 write_extent_buffer(leaf, name, name_ptr, name_len);
95 write_extent_buffer(leaf, data, data_ptr, data_len);
96 btrfs_mark_buffer_dirty(trans, path->nodes[0]);
97
98 return ret;
99}
100
101/*
102 * insert a directory item in the tree, doing all the magic for
103 * both indexes. 'dir' indicates which objectid to insert it into,
104 * 'location' is the key to stuff into the directory item, 'type' is the
105 * type of the inode we're pointing to, and 'index' is the sequence number
106 * to use for the second index (if one is created).
107 * Will return 0 or -ENOMEM
108 */
109int btrfs_insert_dir_item(struct btrfs_trans_handle *trans,
110 const struct fscrypt_str *name, struct btrfs_inode *dir,
111 struct btrfs_key *location, u8 type, u64 index)
112{
113 int ret = 0;
114 int ret2 = 0;
115 struct btrfs_root *root = dir->root;
116 struct btrfs_path *path;
117 struct btrfs_dir_item *dir_item;
118 struct extent_buffer *leaf;
119 unsigned long name_ptr;
120 struct btrfs_key key;
121 struct btrfs_disk_key disk_key;
122 u32 data_size;
123
124 key.objectid = btrfs_ino(dir);
125 key.type = BTRFS_DIR_ITEM_KEY;
126 key.offset = btrfs_name_hash(name->name, name->len);
127
128 path = btrfs_alloc_path();
129 if (!path)
130 return -ENOMEM;
131
132 btrfs_cpu_key_to_disk(&disk_key, location);
133
134 data_size = sizeof(*dir_item) + name->len;
135 dir_item = insert_with_overflow(trans, root, path, &key, data_size,
136 name->name, name->len);
137 if (IS_ERR(dir_item)) {
138 ret = PTR_ERR(dir_item);
139 if (ret == -EEXIST)
140 goto second_insert;
141 goto out_free;
142 }
143
144 if (IS_ENCRYPTED(&dir->vfs_inode))
145 type |= BTRFS_FT_ENCRYPTED;
146
147 leaf = path->nodes[0];
148 btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
149 btrfs_set_dir_flags(leaf, dir_item, type);
150 btrfs_set_dir_data_len(leaf, dir_item, 0);
151 btrfs_set_dir_name_len(leaf, dir_item, name->len);
152 btrfs_set_dir_transid(leaf, dir_item, trans->transid);
153 name_ptr = (unsigned long)(dir_item + 1);
154
155 write_extent_buffer(leaf, name->name, name_ptr, name->len);
156 btrfs_mark_buffer_dirty(trans, leaf);
157
158second_insert:
159 /* FIXME, use some real flag for selecting the extra index */
160 if (root == root->fs_info->tree_root) {
161 ret = 0;
162 goto out_free;
163 }
164 btrfs_release_path(path);
165
166 ret2 = btrfs_insert_delayed_dir_index(trans, name->name, name->len, dir,
167 &disk_key, type, index);
168out_free:
169 btrfs_free_path(path);
170 if (ret)
171 return ret;
172 if (ret2)
173 return ret2;
174 return 0;
175}
176
177static struct btrfs_dir_item *btrfs_lookup_match_dir(
178 struct btrfs_trans_handle *trans,
179 struct btrfs_root *root, struct btrfs_path *path,
180 struct btrfs_key *key, const char *name,
181 int name_len, int mod)
182{
183 const int ins_len = (mod < 0 ? -1 : 0);
184 const int cow = (mod != 0);
185 int ret;
186
187 ret = btrfs_search_slot(trans, root, key, path, ins_len, cow);
188 if (ret < 0)
189 return ERR_PTR(ret);
190 if (ret > 0)
191 return ERR_PTR(-ENOENT);
192
193 return btrfs_match_dir_item_name(root->fs_info, path, name, name_len);
194}
195
196/*
197 * Lookup for a directory item by name.
198 *
199 * @trans: The transaction handle to use. Can be NULL if @mod is 0.
200 * @root: The root of the target tree.
201 * @path: Path to use for the search.
202 * @dir: The inode number (objectid) of the directory.
203 * @name: The name associated to the directory entry we are looking for.
204 * @name_len: The length of the name.
205 * @mod: Used to indicate if the tree search is meant for a read only
206 * lookup, for a modification lookup or for a deletion lookup, so
207 * its value should be 0, 1 or -1, respectively.
208 *
209 * Returns: NULL if the dir item does not exists, an error pointer if an error
210 * happened, or a pointer to a dir item if a dir item exists for the given name.
211 */
212struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
213 struct btrfs_root *root,
214 struct btrfs_path *path, u64 dir,
215 const struct fscrypt_str *name,
216 int mod)
217{
218 struct btrfs_key key;
219 struct btrfs_dir_item *di;
220
221 key.objectid = dir;
222 key.type = BTRFS_DIR_ITEM_KEY;
223 key.offset = btrfs_name_hash(name->name, name->len);
224
225 di = btrfs_lookup_match_dir(trans, root, path, &key, name->name,
226 name->len, mod);
227 if (IS_ERR(di) && PTR_ERR(di) == -ENOENT)
228 return NULL;
229
230 return di;
231}
232
233int btrfs_check_dir_item_collision(struct btrfs_root *root, u64 dir,
234 const struct fscrypt_str *name)
235{
236 int ret;
237 struct btrfs_key key;
238 struct btrfs_dir_item *di;
239 int data_size;
240 struct extent_buffer *leaf;
241 int slot;
242 struct btrfs_path *path;
243
244 path = btrfs_alloc_path();
245 if (!path)
246 return -ENOMEM;
247
248 key.objectid = dir;
249 key.type = BTRFS_DIR_ITEM_KEY;
250 key.offset = btrfs_name_hash(name->name, name->len);
251
252 di = btrfs_lookup_match_dir(NULL, root, path, &key, name->name,
253 name->len, 0);
254 if (IS_ERR(di)) {
255 ret = PTR_ERR(di);
256 /* Nothing found, we're safe */
257 if (ret == -ENOENT) {
258 ret = 0;
259 goto out;
260 }
261
262 if (ret < 0)
263 goto out;
264 }
265
266 /* we found an item, look for our name in the item */
267 if (di) {
268 /* our exact name was found */
269 ret = -EEXIST;
270 goto out;
271 }
272
273 /* See if there is room in the item to insert this name. */
274 data_size = sizeof(*di) + name->len;
275 leaf = path->nodes[0];
276 slot = path->slots[0];
277 if (data_size + btrfs_item_size(leaf, slot) +
278 sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root->fs_info)) {
279 ret = -EOVERFLOW;
280 } else {
281 /* plenty of insertion room */
282 ret = 0;
283 }
284out:
285 btrfs_free_path(path);
286 return ret;
287}
288
289/*
290 * Lookup for a directory index item by name and index number.
291 *
292 * @trans: The transaction handle to use. Can be NULL if @mod is 0.
293 * @root: The root of the target tree.
294 * @path: Path to use for the search.
295 * @dir: The inode number (objectid) of the directory.
296 * @index: The index number.
297 * @name: The name associated to the directory entry we are looking for.
298 * @name_len: The length of the name.
299 * @mod: Used to indicate if the tree search is meant for a read only
300 * lookup, for a modification lookup or for a deletion lookup, so
301 * its value should be 0, 1 or -1, respectively.
302 *
303 * Returns: NULL if the dir index item does not exists, an error pointer if an
304 * error happened, or a pointer to a dir item if the dir index item exists and
305 * matches the criteria (name and index number).
306 */
307struct btrfs_dir_item *
308btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
309 struct btrfs_root *root,
310 struct btrfs_path *path, u64 dir,
311 u64 index, const struct fscrypt_str *name, int mod)
312{
313 struct btrfs_dir_item *di;
314 struct btrfs_key key;
315
316 key.objectid = dir;
317 key.type = BTRFS_DIR_INDEX_KEY;
318 key.offset = index;
319
320 di = btrfs_lookup_match_dir(trans, root, path, &key, name->name,
321 name->len, mod);
322 if (di == ERR_PTR(-ENOENT))
323 return NULL;
324
325 return di;
326}
327
328struct btrfs_dir_item *
329btrfs_search_dir_index_item(struct btrfs_root *root, struct btrfs_path *path,
330 u64 dirid, const struct fscrypt_str *name)
331{
332 struct btrfs_dir_item *di;
333 struct btrfs_key key;
334 int ret;
335
336 key.objectid = dirid;
337 key.type = BTRFS_DIR_INDEX_KEY;
338 key.offset = 0;
339
340 btrfs_for_each_slot(root, &key, &key, path, ret) {
341 if (key.objectid != dirid || key.type != BTRFS_DIR_INDEX_KEY)
342 break;
343
344 di = btrfs_match_dir_item_name(root->fs_info, path,
345 name->name, name->len);
346 if (di)
347 return di;
348 }
349 /* Adjust return code if the key was not found in the next leaf. */
350 if (ret > 0)
351 ret = 0;
352
353 return ERR_PTR(ret);
354}
355
356struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,
357 struct btrfs_root *root,
358 struct btrfs_path *path, u64 dir,
359 const char *name, u16 name_len,
360 int mod)
361{
362 struct btrfs_key key;
363 struct btrfs_dir_item *di;
364
365 key.objectid = dir;
366 key.type = BTRFS_XATTR_ITEM_KEY;
367 key.offset = btrfs_name_hash(name, name_len);
368
369 di = btrfs_lookup_match_dir(trans, root, path, &key, name, name_len, mod);
370 if (IS_ERR(di) && PTR_ERR(di) == -ENOENT)
371 return NULL;
372
373 return di;
374}
375
376/*
377 * helper function to look at the directory item pointed to by 'path'
378 * this walks through all the entries in a dir item and finds one
379 * for a specific name.
380 */
381struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_fs_info *fs_info,
382 struct btrfs_path *path,
383 const char *name, int name_len)
384{
385 struct btrfs_dir_item *dir_item;
386 unsigned long name_ptr;
387 u32 total_len;
388 u32 cur = 0;
389 u32 this_len;
390 struct extent_buffer *leaf;
391
392 leaf = path->nodes[0];
393 dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
394
395 total_len = btrfs_item_size(leaf, path->slots[0]);
396 while (cur < total_len) {
397 this_len = sizeof(*dir_item) +
398 btrfs_dir_name_len(leaf, dir_item) +
399 btrfs_dir_data_len(leaf, dir_item);
400 name_ptr = (unsigned long)(dir_item + 1);
401
402 if (btrfs_dir_name_len(leaf, dir_item) == name_len &&
403 memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
404 return dir_item;
405
406 cur += this_len;
407 dir_item = (struct btrfs_dir_item *)((char *)dir_item +
408 this_len);
409 }
410 return NULL;
411}
412
413/*
414 * given a pointer into a directory item, delete it. This
415 * handles items that have more than one entry in them.
416 */
417int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
418 struct btrfs_root *root,
419 struct btrfs_path *path,
420 struct btrfs_dir_item *di)
421{
422
423 struct extent_buffer *leaf;
424 u32 sub_item_len;
425 u32 item_len;
426 int ret = 0;
427
428 leaf = path->nodes[0];
429 sub_item_len = sizeof(*di) + btrfs_dir_name_len(leaf, di) +
430 btrfs_dir_data_len(leaf, di);
431 item_len = btrfs_item_size(leaf, path->slots[0]);
432 if (sub_item_len == item_len) {
433 ret = btrfs_del_item(trans, root, path);
434 } else {
435 /* MARKER */
436 unsigned long ptr = (unsigned long)di;
437 unsigned long start;
438
439 start = btrfs_item_ptr_offset(leaf, path->slots[0]);
440 memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
441 item_len - (ptr + sub_item_len - start));
442 btrfs_truncate_item(trans, path, item_len - sub_item_len, 1);
443 }
444 return ret;
445}
1/*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
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.
7 *
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.
12 *
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.
17 */
18
19#include "ctree.h"
20#include "disk-io.h"
21#include "hash.h"
22#include "transaction.h"
23
24static struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
25 struct btrfs_path *path,
26 const char *name, int name_len);
27
28/*
29 * insert a name into a directory, doing overflow properly if there is a hash
30 * collision. data_size indicates how big the item inserted should be. On
31 * success a struct btrfs_dir_item pointer is returned, otherwise it is
32 * an ERR_PTR.
33 *
34 * The name is not copied into the dir item, you have to do that yourself.
35 */
36static struct btrfs_dir_item *insert_with_overflow(struct btrfs_trans_handle
37 *trans,
38 struct btrfs_root *root,
39 struct btrfs_path *path,
40 struct btrfs_key *cpu_key,
41 u32 data_size,
42 const char *name,
43 int name_len)
44{
45 int ret;
46 char *ptr;
47 struct btrfs_item *item;
48 struct extent_buffer *leaf;
49
50 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
51 if (ret == -EEXIST) {
52 struct btrfs_dir_item *di;
53 di = btrfs_match_dir_item_name(root, path, name, name_len);
54 if (di)
55 return ERR_PTR(-EEXIST);
56 btrfs_extend_item(root, path, data_size);
57 } else if (ret < 0)
58 return ERR_PTR(ret);
59 WARN_ON(ret > 0);
60 leaf = path->nodes[0];
61 item = btrfs_item_nr(path->slots[0]);
62 ptr = btrfs_item_ptr(leaf, path->slots[0], char);
63 BUG_ON(data_size > btrfs_item_size(leaf, item));
64 ptr += btrfs_item_size(leaf, item) - data_size;
65 return (struct btrfs_dir_item *)ptr;
66}
67
68/*
69 * xattrs work a lot like directories, this inserts an xattr item
70 * into the tree
71 */
72int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,
73 struct btrfs_root *root,
74 struct btrfs_path *path, u64 objectid,
75 const char *name, u16 name_len,
76 const void *data, u16 data_len)
77{
78 int ret = 0;
79 struct btrfs_dir_item *dir_item;
80 unsigned long name_ptr, data_ptr;
81 struct btrfs_key key, location;
82 struct btrfs_disk_key disk_key;
83 struct extent_buffer *leaf;
84 u32 data_size;
85
86 BUG_ON(name_len + data_len > BTRFS_MAX_XATTR_SIZE(root));
87
88 key.objectid = objectid;
89 btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
90 key.offset = btrfs_name_hash(name, name_len);
91
92 data_size = sizeof(*dir_item) + name_len + data_len;
93 dir_item = insert_with_overflow(trans, root, path, &key, data_size,
94 name, name_len);
95 if (IS_ERR(dir_item))
96 return PTR_ERR(dir_item);
97 memset(&location, 0, sizeof(location));
98
99 leaf = path->nodes[0];
100 btrfs_cpu_key_to_disk(&disk_key, &location);
101 btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
102 btrfs_set_dir_type(leaf, dir_item, BTRFS_FT_XATTR);
103 btrfs_set_dir_name_len(leaf, dir_item, name_len);
104 btrfs_set_dir_transid(leaf, dir_item, trans->transid);
105 btrfs_set_dir_data_len(leaf, dir_item, data_len);
106 name_ptr = (unsigned long)(dir_item + 1);
107 data_ptr = (unsigned long)((char *)name_ptr + name_len);
108
109 write_extent_buffer(leaf, name, name_ptr, name_len);
110 write_extent_buffer(leaf, data, data_ptr, data_len);
111 btrfs_mark_buffer_dirty(path->nodes[0]);
112
113 return ret;
114}
115
116/*
117 * insert a directory item in the tree, doing all the magic for
118 * both indexes. 'dir' indicates which objectid to insert it into,
119 * 'location' is the key to stuff into the directory item, 'type' is the
120 * type of the inode we're pointing to, and 'index' is the sequence number
121 * to use for the second index (if one is created).
122 * Will return 0 or -ENOMEM
123 */
124int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
125 *root, const char *name, int name_len,
126 struct inode *dir, struct btrfs_key *location,
127 u8 type, u64 index)
128{
129 int ret = 0;
130 int ret2 = 0;
131 struct btrfs_path *path;
132 struct btrfs_dir_item *dir_item;
133 struct extent_buffer *leaf;
134 unsigned long name_ptr;
135 struct btrfs_key key;
136 struct btrfs_disk_key disk_key;
137 u32 data_size;
138
139 key.objectid = btrfs_ino(dir);
140 btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
141 key.offset = btrfs_name_hash(name, name_len);
142
143 path = btrfs_alloc_path();
144 if (!path)
145 return -ENOMEM;
146 path->leave_spinning = 1;
147
148 btrfs_cpu_key_to_disk(&disk_key, location);
149
150 data_size = sizeof(*dir_item) + name_len;
151 dir_item = insert_with_overflow(trans, root, path, &key, data_size,
152 name, name_len);
153 if (IS_ERR(dir_item)) {
154 ret = PTR_ERR(dir_item);
155 if (ret == -EEXIST)
156 goto second_insert;
157 goto out_free;
158 }
159
160 leaf = path->nodes[0];
161 btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
162 btrfs_set_dir_type(leaf, dir_item, type);
163 btrfs_set_dir_data_len(leaf, dir_item, 0);
164 btrfs_set_dir_name_len(leaf, dir_item, name_len);
165 btrfs_set_dir_transid(leaf, dir_item, trans->transid);
166 name_ptr = (unsigned long)(dir_item + 1);
167
168 write_extent_buffer(leaf, name, name_ptr, name_len);
169 btrfs_mark_buffer_dirty(leaf);
170
171second_insert:
172 /* FIXME, use some real flag for selecting the extra index */
173 if (root == root->fs_info->tree_root) {
174 ret = 0;
175 goto out_free;
176 }
177 btrfs_release_path(path);
178
179 ret2 = btrfs_insert_delayed_dir_index(trans, root, name, name_len, dir,
180 &disk_key, type, index);
181out_free:
182 btrfs_free_path(path);
183 if (ret)
184 return ret;
185 if (ret2)
186 return ret2;
187 return 0;
188}
189
190/*
191 * lookup a directory item based on name. 'dir' is the objectid
192 * we're searching in, and 'mod' tells us if you plan on deleting the
193 * item (use mod < 0) or changing the options (use mod > 0)
194 */
195struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
196 struct btrfs_root *root,
197 struct btrfs_path *path, u64 dir,
198 const char *name, int name_len,
199 int mod)
200{
201 int ret;
202 struct btrfs_key key;
203 int ins_len = mod < 0 ? -1 : 0;
204 int cow = mod != 0;
205
206 key.objectid = dir;
207 btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
208
209 key.offset = btrfs_name_hash(name, name_len);
210
211 ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
212 if (ret < 0)
213 return ERR_PTR(ret);
214 if (ret > 0)
215 return NULL;
216
217 return btrfs_match_dir_item_name(root, path, name, name_len);
218}
219
220int btrfs_check_dir_item_collision(struct btrfs_root *root, u64 dir,
221 const char *name, int name_len)
222{
223 int ret;
224 struct btrfs_key key;
225 struct btrfs_dir_item *di;
226 int data_size;
227 struct extent_buffer *leaf;
228 int slot;
229 struct btrfs_path *path;
230
231
232 path = btrfs_alloc_path();
233 if (!path)
234 return -ENOMEM;
235
236 key.objectid = dir;
237 btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
238 key.offset = btrfs_name_hash(name, name_len);
239
240 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
241
242 /* return back any errors */
243 if (ret < 0)
244 goto out;
245
246 /* nothing found, we're safe */
247 if (ret > 0) {
248 ret = 0;
249 goto out;
250 }
251
252 /* we found an item, look for our name in the item */
253 di = btrfs_match_dir_item_name(root, path, name, name_len);
254 if (di) {
255 /* our exact name was found */
256 ret = -EEXIST;
257 goto out;
258 }
259
260 /*
261 * see if there is room in the item to insert this
262 * name
263 */
264 data_size = sizeof(*di) + name_len;
265 leaf = path->nodes[0];
266 slot = path->slots[0];
267 if (data_size + btrfs_item_size_nr(leaf, slot) +
268 sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root)) {
269 ret = -EOVERFLOW;
270 } else {
271 /* plenty of insertion room */
272 ret = 0;
273 }
274out:
275 btrfs_free_path(path);
276 return ret;
277}
278
279/*
280 * lookup a directory item based on index. 'dir' is the objectid
281 * we're searching in, and 'mod' tells us if you plan on deleting the
282 * item (use mod < 0) or changing the options (use mod > 0)
283 *
284 * The name is used to make sure the index really points to the name you were
285 * looking for.
286 */
287struct btrfs_dir_item *
288btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
289 struct btrfs_root *root,
290 struct btrfs_path *path, u64 dir,
291 u64 objectid, const char *name, int name_len,
292 int mod)
293{
294 int ret;
295 struct btrfs_key key;
296 int ins_len = mod < 0 ? -1 : 0;
297 int cow = mod != 0;
298
299 key.objectid = dir;
300 btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
301 key.offset = objectid;
302
303 ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
304 if (ret < 0)
305 return ERR_PTR(ret);
306 if (ret > 0)
307 return ERR_PTR(-ENOENT);
308 return btrfs_match_dir_item_name(root, path, name, name_len);
309}
310
311struct btrfs_dir_item *
312btrfs_search_dir_index_item(struct btrfs_root *root,
313 struct btrfs_path *path, u64 dirid,
314 const char *name, int name_len)
315{
316 struct extent_buffer *leaf;
317 struct btrfs_dir_item *di;
318 struct btrfs_key key;
319 u32 nritems;
320 int ret;
321
322 key.objectid = dirid;
323 key.type = BTRFS_DIR_INDEX_KEY;
324 key.offset = 0;
325
326 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
327 if (ret < 0)
328 return ERR_PTR(ret);
329
330 leaf = path->nodes[0];
331 nritems = btrfs_header_nritems(leaf);
332
333 while (1) {
334 if (path->slots[0] >= nritems) {
335 ret = btrfs_next_leaf(root, path);
336 if (ret < 0)
337 return ERR_PTR(ret);
338 if (ret > 0)
339 break;
340 leaf = path->nodes[0];
341 nritems = btrfs_header_nritems(leaf);
342 continue;
343 }
344
345 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
346 if (key.objectid != dirid || key.type != BTRFS_DIR_INDEX_KEY)
347 break;
348
349 di = btrfs_match_dir_item_name(root, path, name, name_len);
350 if (di)
351 return di;
352
353 path->slots[0]++;
354 }
355 return NULL;
356}
357
358struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,
359 struct btrfs_root *root,
360 struct btrfs_path *path, u64 dir,
361 const char *name, u16 name_len,
362 int mod)
363{
364 int ret;
365 struct btrfs_key key;
366 int ins_len = mod < 0 ? -1 : 0;
367 int cow = mod != 0;
368
369 key.objectid = dir;
370 btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
371 key.offset = btrfs_name_hash(name, name_len);
372 ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
373 if (ret < 0)
374 return ERR_PTR(ret);
375 if (ret > 0)
376 return NULL;
377
378 return btrfs_match_dir_item_name(root, path, name, name_len);
379}
380
381/*
382 * helper function to look at the directory item pointed to by 'path'
383 * this walks through all the entries in a dir item and finds one
384 * for a specific name.
385 */
386static struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
387 struct btrfs_path *path,
388 const char *name, int name_len)
389{
390 struct btrfs_dir_item *dir_item;
391 unsigned long name_ptr;
392 u32 total_len;
393 u32 cur = 0;
394 u32 this_len;
395 struct extent_buffer *leaf;
396
397 leaf = path->nodes[0];
398 dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
399 if (verify_dir_item(root, leaf, dir_item))
400 return NULL;
401
402 total_len = btrfs_item_size_nr(leaf, path->slots[0]);
403 while (cur < total_len) {
404 this_len = sizeof(*dir_item) +
405 btrfs_dir_name_len(leaf, dir_item) +
406 btrfs_dir_data_len(leaf, dir_item);
407 name_ptr = (unsigned long)(dir_item + 1);
408
409 if (btrfs_dir_name_len(leaf, dir_item) == name_len &&
410 memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
411 return dir_item;
412
413 cur += this_len;
414 dir_item = (struct btrfs_dir_item *)((char *)dir_item +
415 this_len);
416 }
417 return NULL;
418}
419
420/*
421 * given a pointer into a directory item, delete it. This
422 * handles items that have more than one entry in them.
423 */
424int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
425 struct btrfs_root *root,
426 struct btrfs_path *path,
427 struct btrfs_dir_item *di)
428{
429
430 struct extent_buffer *leaf;
431 u32 sub_item_len;
432 u32 item_len;
433 int ret = 0;
434
435 leaf = path->nodes[0];
436 sub_item_len = sizeof(*di) + btrfs_dir_name_len(leaf, di) +
437 btrfs_dir_data_len(leaf, di);
438 item_len = btrfs_item_size_nr(leaf, path->slots[0]);
439 if (sub_item_len == item_len) {
440 ret = btrfs_del_item(trans, root, path);
441 } else {
442 /* MARKER */
443 unsigned long ptr = (unsigned long)di;
444 unsigned long start;
445
446 start = btrfs_item_ptr_offset(leaf, path->slots[0]);
447 memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
448 item_len - (ptr + sub_item_len - start));
449 btrfs_truncate_item(root, path, item_len - sub_item_len, 1);
450 }
451 return ret;
452}
453
454int verify_dir_item(struct btrfs_root *root,
455 struct extent_buffer *leaf,
456 struct btrfs_dir_item *dir_item)
457{
458 u16 namelen = BTRFS_NAME_LEN;
459 u8 type = btrfs_dir_type(leaf, dir_item);
460
461 if (type >= BTRFS_FT_MAX) {
462 btrfs_crit(root->fs_info, "invalid dir item type: %d",
463 (int)type);
464 return 1;
465 }
466
467 if (type == BTRFS_FT_XATTR)
468 namelen = XATTR_NAME_MAX;
469
470 if (btrfs_dir_name_len(leaf, dir_item) > namelen) {
471 btrfs_crit(root->fs_info, "invalid dir item name len: %u",
472 (unsigned)btrfs_dir_data_len(leaf, dir_item));
473 return 1;
474 }
475
476 /* BTRFS_MAX_XATTR_SIZE is the same for all dir items */
477 if ((btrfs_dir_data_len(leaf, dir_item) +
478 btrfs_dir_name_len(leaf, dir_item)) > BTRFS_MAX_XATTR_SIZE(root)) {
479 btrfs_crit(root->fs_info, "invalid dir item name + data len: %u + %u",
480 (unsigned)btrfs_dir_name_len(leaf, dir_item),
481 (unsigned)btrfs_dir_data_len(leaf, dir_item));
482 return 1;
483 }
484
485 return 0;
486}