Line data Source code
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 : */
21 0 : static 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 0 : struct btrfs_fs_info *fs_info = root->fs_info;
31 0 : int ret;
32 0 : char *ptr;
33 0 : struct extent_buffer *leaf;
34 :
35 0 : ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
36 0 : if (ret == -EEXIST) {
37 0 : struct btrfs_dir_item *di;
38 0 : di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
39 0 : if (di)
40 : return ERR_PTR(-EEXIST);
41 0 : btrfs_extend_item(path, data_size);
42 0 : } else if (ret < 0)
43 0 : return ERR_PTR(ret);
44 0 : WARN_ON(ret > 0);
45 0 : leaf = path->nodes[0];
46 0 : ptr = btrfs_item_ptr(leaf, path->slots[0], char);
47 0 : ASSERT(data_size <= btrfs_item_size(leaf, path->slots[0]));
48 0 : ptr += btrfs_item_size(leaf, path->slots[0]) - data_size;
49 0 : 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 : */
56 0 : int 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 0 : int ret = 0;
63 0 : struct btrfs_dir_item *dir_item;
64 0 : unsigned long name_ptr, data_ptr;
65 0 : struct btrfs_key key, location;
66 0 : struct btrfs_disk_key disk_key;
67 0 : struct extent_buffer *leaf;
68 0 : u32 data_size;
69 :
70 0 : if (name_len + data_len > BTRFS_MAX_XATTR_SIZE(root->fs_info))
71 : return -ENOSPC;
72 :
73 0 : key.objectid = objectid;
74 0 : key.type = BTRFS_XATTR_ITEM_KEY;
75 0 : key.offset = btrfs_name_hash(name, name_len);
76 :
77 0 : data_size = sizeof(*dir_item) + name_len + data_len;
78 0 : dir_item = insert_with_overflow(trans, root, path, &key, data_size,
79 : name, name_len);
80 0 : if (IS_ERR(dir_item))
81 0 : return PTR_ERR(dir_item);
82 0 : memset(&location, 0, sizeof(location));
83 :
84 0 : leaf = path->nodes[0];
85 0 : btrfs_cpu_key_to_disk(&disk_key, &location);
86 0 : btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
87 0 : btrfs_set_dir_flags(leaf, dir_item, BTRFS_FT_XATTR);
88 0 : btrfs_set_dir_name_len(leaf, dir_item, name_len);
89 0 : btrfs_set_dir_transid(leaf, dir_item, trans->transid);
90 0 : btrfs_set_dir_data_len(leaf, dir_item, data_len);
91 0 : name_ptr = (unsigned long)(dir_item + 1);
92 0 : data_ptr = (unsigned long)((char *)name_ptr + name_len);
93 :
94 0 : write_extent_buffer(leaf, name, name_ptr, name_len);
95 0 : write_extent_buffer(leaf, data, data_ptr, data_len);
96 0 : btrfs_mark_buffer_dirty(path->nodes[0]);
97 :
98 0 : 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 : */
109 0 : int 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 0 : int ret = 0;
114 0 : int ret2 = 0;
115 0 : struct btrfs_root *root = dir->root;
116 0 : struct btrfs_path *path;
117 0 : struct btrfs_dir_item *dir_item;
118 0 : struct extent_buffer *leaf;
119 0 : unsigned long name_ptr;
120 0 : struct btrfs_key key;
121 0 : struct btrfs_disk_key disk_key;
122 0 : u32 data_size;
123 :
124 0 : key.objectid = btrfs_ino(dir);
125 0 : key.type = BTRFS_DIR_ITEM_KEY;
126 0 : key.offset = btrfs_name_hash(name->name, name->len);
127 :
128 0 : path = btrfs_alloc_path();
129 0 : if (!path)
130 : return -ENOMEM;
131 :
132 0 : btrfs_cpu_key_to_disk(&disk_key, location);
133 :
134 0 : data_size = sizeof(*dir_item) + name->len;
135 0 : dir_item = insert_with_overflow(trans, root, path, &key, data_size,
136 0 : name->name, name->len);
137 0 : if (IS_ERR(dir_item)) {
138 0 : ret = PTR_ERR(dir_item);
139 0 : if (ret == -EEXIST)
140 0 : goto second_insert;
141 0 : goto out_free;
142 : }
143 :
144 0 : if (IS_ENCRYPTED(&dir->vfs_inode))
145 0 : type |= BTRFS_FT_ENCRYPTED;
146 :
147 0 : leaf = path->nodes[0];
148 0 : btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
149 0 : btrfs_set_dir_flags(leaf, dir_item, type);
150 0 : btrfs_set_dir_data_len(leaf, dir_item, 0);
151 0 : btrfs_set_dir_name_len(leaf, dir_item, name->len);
152 0 : btrfs_set_dir_transid(leaf, dir_item, trans->transid);
153 0 : name_ptr = (unsigned long)(dir_item + 1);
154 :
155 0 : write_extent_buffer(leaf, name->name, name_ptr, name->len);
156 0 : btrfs_mark_buffer_dirty(leaf);
157 :
158 0 : second_insert:
159 : /* FIXME, use some real flag for selecting the extra index */
160 0 : if (root == root->fs_info->tree_root) {
161 0 : ret = 0;
162 0 : goto out_free;
163 : }
164 0 : btrfs_release_path(path);
165 :
166 0 : ret2 = btrfs_insert_delayed_dir_index(trans, name->name, name->len, dir,
167 : &disk_key, type, index);
168 0 : out_free:
169 0 : btrfs_free_path(path);
170 0 : if (ret)
171 : return ret;
172 0 : if (ret2)
173 0 : return ret2;
174 : return 0;
175 : }
176 :
177 0 : static 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 0 : const int ins_len = (mod < 0 ? -1 : 0);
184 0 : const int cow = (mod != 0);
185 0 : int ret;
186 :
187 0 : ret = btrfs_search_slot(trans, root, key, path, ins_len, cow);
188 0 : if (ret < 0)
189 0 : return ERR_PTR(ret);
190 0 : if (ret > 0)
191 : return ERR_PTR(-ENOENT);
192 :
193 0 : 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 : */
212 0 : struct 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 0 : struct btrfs_key key;
219 0 : struct btrfs_dir_item *di;
220 :
221 0 : key.objectid = dir;
222 0 : key.type = BTRFS_DIR_ITEM_KEY;
223 0 : key.offset = btrfs_name_hash(name->name, name->len);
224 :
225 0 : di = btrfs_lookup_match_dir(trans, root, path, &key, name->name,
226 0 : name->len, mod);
227 0 : if (IS_ERR(di) && PTR_ERR(di) == -ENOENT)
228 0 : return NULL;
229 :
230 : return di;
231 : }
232 :
233 0 : int btrfs_check_dir_item_collision(struct btrfs_root *root, u64 dir,
234 : const struct fscrypt_str *name)
235 : {
236 0 : int ret;
237 0 : struct btrfs_key key;
238 0 : struct btrfs_dir_item *di;
239 0 : int data_size;
240 0 : struct extent_buffer *leaf;
241 0 : int slot;
242 0 : struct btrfs_path *path;
243 :
244 0 : path = btrfs_alloc_path();
245 0 : if (!path)
246 : return -ENOMEM;
247 :
248 0 : key.objectid = dir;
249 0 : key.type = BTRFS_DIR_ITEM_KEY;
250 0 : key.offset = btrfs_name_hash(name->name, name->len);
251 :
252 0 : di = btrfs_lookup_match_dir(NULL, root, path, &key, name->name,
253 0 : name->len, 0);
254 0 : if (IS_ERR(di)) {
255 0 : ret = PTR_ERR(di);
256 : /* Nothing found, we're safe */
257 0 : if (ret == -ENOENT) {
258 0 : ret = 0;
259 0 : goto out;
260 : }
261 :
262 0 : if (ret < 0)
263 0 : goto out;
264 : }
265 :
266 : /* we found an item, look for our name in the item */
267 0 : if (di) {
268 : /* our exact name was found */
269 0 : ret = -EEXIST;
270 0 : goto out;
271 : }
272 :
273 : /* See if there is room in the item to insert this name. */
274 0 : data_size = sizeof(*di) + name->len;
275 0 : leaf = path->nodes[0];
276 0 : slot = path->slots[0];
277 0 : if (data_size + btrfs_item_size(leaf, slot) +
278 0 : sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root->fs_info)) {
279 : ret = -EOVERFLOW;
280 : } else {
281 : /* plenty of insertion room */
282 0 : ret = 0;
283 : }
284 0 : out:
285 0 : btrfs_free_path(path);
286 0 : 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 : */
307 : struct btrfs_dir_item *
308 0 : btrfs_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 0 : struct btrfs_dir_item *di;
314 0 : struct btrfs_key key;
315 :
316 0 : key.objectid = dir;
317 0 : key.type = BTRFS_DIR_INDEX_KEY;
318 0 : key.offset = index;
319 :
320 0 : di = btrfs_lookup_match_dir(trans, root, path, &key, name->name,
321 0 : name->len, mod);
322 0 : if (di == ERR_PTR(-ENOENT))
323 0 : return NULL;
324 :
325 : return di;
326 : }
327 :
328 : struct btrfs_dir_item *
329 0 : btrfs_search_dir_index_item(struct btrfs_root *root, struct btrfs_path *path,
330 : u64 dirid, const struct fscrypt_str *name)
331 : {
332 0 : struct btrfs_dir_item *di;
333 0 : struct btrfs_key key;
334 0 : int ret;
335 :
336 0 : key.objectid = dirid;
337 0 : key.type = BTRFS_DIR_INDEX_KEY;
338 0 : key.offset = 0;
339 :
340 0 : btrfs_for_each_slot(root, &key, &key, path, ret) {
341 0 : if (key.objectid != dirid || key.type != BTRFS_DIR_INDEX_KEY)
342 : break;
343 :
344 0 : di = btrfs_match_dir_item_name(root->fs_info, path,
345 0 : name->name, name->len);
346 0 : if (di)
347 0 : return di;
348 : }
349 : /* Adjust return code if the key was not found in the next leaf. */
350 0 : if (ret > 0)
351 : ret = 0;
352 :
353 0 : return ERR_PTR(ret);
354 : }
355 :
356 0 : struct 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 0 : struct btrfs_key key;
363 0 : struct btrfs_dir_item *di;
364 :
365 0 : key.objectid = dir;
366 0 : key.type = BTRFS_XATTR_ITEM_KEY;
367 0 : key.offset = btrfs_name_hash(name, name_len);
368 :
369 0 : di = btrfs_lookup_match_dir(trans, root, path, &key, name, name_len, mod);
370 0 : if (IS_ERR(di) && PTR_ERR(di) == -ENOENT)
371 0 : 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 : */
381 0 : struct 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 0 : struct btrfs_dir_item *dir_item;
386 0 : unsigned long name_ptr;
387 0 : u32 total_len;
388 0 : u32 cur = 0;
389 0 : u32 this_len;
390 0 : struct extent_buffer *leaf;
391 :
392 0 : leaf = path->nodes[0];
393 0 : dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
394 :
395 0 : total_len = btrfs_item_size(leaf, path->slots[0]);
396 0 : while (cur < total_len) {
397 0 : this_len = sizeof(*dir_item) +
398 0 : btrfs_dir_name_len(leaf, dir_item) +
399 0 : btrfs_dir_data_len(leaf, dir_item);
400 0 : name_ptr = (unsigned long)(dir_item + 1);
401 :
402 0 : if (btrfs_dir_name_len(leaf, dir_item) == name_len &&
403 0 : memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
404 0 : return dir_item;
405 :
406 0 : cur += this_len;
407 0 : 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 : */
417 0 : int 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 0 : struct extent_buffer *leaf;
424 0 : u32 sub_item_len;
425 0 : u32 item_len;
426 0 : int ret = 0;
427 :
428 0 : leaf = path->nodes[0];
429 0 : sub_item_len = sizeof(*di) + btrfs_dir_name_len(leaf, di) +
430 0 : btrfs_dir_data_len(leaf, di);
431 0 : item_len = btrfs_item_size(leaf, path->slots[0]);
432 0 : if (sub_item_len == item_len) {
433 0 : ret = btrfs_del_item(trans, root, path);
434 : } else {
435 : /* MARKER */
436 0 : unsigned long ptr = (unsigned long)di;
437 0 : unsigned long start;
438 :
439 0 : start = btrfs_item_ptr_offset(leaf, path->slots[0]);
440 0 : memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
441 0 : item_len - (ptr + sub_item_len - start));
442 0 : btrfs_truncate_item(path, item_len - sub_item_len, 1);
443 : }
444 0 : return ret;
445 : }
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