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