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