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 */
insert_with_overflow(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_path * path,struct btrfs_key * cpu_key,u32 data_size,const char * name,int name_len)32 static 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 int ret;
42 char *ptr;
43 struct btrfs_item *item;
44 struct extent_buffer *leaf;
45
46 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
47 if (ret == -EEXIST) {
48 struct btrfs_dir_item *di;
49 di = btrfs_match_dir_item_name(root, path, name, name_len);
50 if (di)
51 return ERR_PTR(-EEXIST);
52 ret = btrfs_extend_item(trans, root, path, data_size);
53 WARN_ON(ret > 0);
54 }
55 if (ret < 0)
56 return ERR_PTR(ret);
57 WARN_ON(ret > 0);
58 leaf = path->nodes[0];
59 item = btrfs_item_nr(leaf, path->slots[0]);
60 ptr = btrfs_item_ptr(leaf, path->slots[0], char);
61 BUG_ON(data_size > btrfs_item_size(leaf, item));
62 ptr += btrfs_item_size(leaf, item) - data_size;
63 return (struct btrfs_dir_item *)ptr;
64 }
65
66 /*
67 * xattrs work a lot like directories, this inserts an xattr item
68 * into the tree
69 */
btrfs_insert_xattr_item(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_path * path,u64 objectid,const char * name,u16 name_len,const void * data,u16 data_len)70 int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,
71 struct btrfs_root *root,
72 struct btrfs_path *path, u64 objectid,
73 const char *name, u16 name_len,
74 const void *data, u16 data_len)
75 {
76 int ret = 0;
77 struct btrfs_dir_item *dir_item;
78 unsigned long name_ptr, data_ptr;
79 struct btrfs_key key, location;
80 struct btrfs_disk_key disk_key;
81 struct extent_buffer *leaf;
82 u32 data_size;
83
84 BUG_ON(name_len + data_len > BTRFS_MAX_XATTR_SIZE(root));
85
86 key.objectid = objectid;
87 btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
88 key.offset = btrfs_name_hash(name, name_len);
89
90 data_size = sizeof(*dir_item) + name_len + data_len;
91 dir_item = insert_with_overflow(trans, root, path, &key, data_size,
92 name, name_len);
93 /*
94 * FIXME: at some point we should handle xattr's that are larger than
95 * what we can fit in our leaf. We set location to NULL b/c we arent
96 * pointing at anything else, that will change if we store the xattr
97 * data in a separate inode.
98 */
99 BUG_ON(IS_ERR(dir_item));
100 memset(&location, 0, sizeof(location));
101
102 leaf = path->nodes[0];
103 btrfs_cpu_key_to_disk(&disk_key, &location);
104 btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
105 btrfs_set_dir_type(leaf, dir_item, BTRFS_FT_XATTR);
106 btrfs_set_dir_name_len(leaf, dir_item, name_len);
107 btrfs_set_dir_transid(leaf, dir_item, trans->transid);
108 btrfs_set_dir_data_len(leaf, dir_item, data_len);
109 name_ptr = (unsigned long)(dir_item + 1);
110 data_ptr = (unsigned long)((char *)name_ptr + name_len);
111
112 write_extent_buffer(leaf, name, name_ptr, name_len);
113 write_extent_buffer(leaf, data, data_ptr, data_len);
114 btrfs_mark_buffer_dirty(path->nodes[0]);
115
116 return ret;
117 }
118
119 /*
120 * insert a directory item in the tree, doing all the magic for
121 * both indexes. 'dir' indicates which objectid to insert it into,
122 * 'location' is the key to stuff into the directory item, 'type' is the
123 * type of the inode we're pointing to, and 'index' is the sequence number
124 * to use for the second index (if one is created).
125 */
btrfs_insert_dir_item(struct btrfs_trans_handle * trans,struct btrfs_root * root,const char * name,int name_len,u64 dir,struct btrfs_key * location,u8 type,u64 index)126 int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
127 *root, const char *name, int name_len, u64 dir,
128 struct btrfs_key *location, u8 type, u64 index)
129 {
130 int ret = 0;
131 int ret2 = 0;
132 struct btrfs_path *path;
133 struct btrfs_dir_item *dir_item;
134 struct extent_buffer *leaf;
135 unsigned long name_ptr;
136 struct btrfs_key key;
137 struct btrfs_disk_key disk_key;
138 u32 data_size;
139
140 key.objectid = dir;
141 btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
142 key.offset = btrfs_name_hash(name, name_len);
143
144 path = btrfs_alloc_path();
145 path->leave_spinning = 1;
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_cpu_key_to_disk(&disk_key, location);
159 btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
160 btrfs_set_dir_type(leaf, dir_item, type);
161 btrfs_set_dir_data_len(leaf, dir_item, 0);
162 btrfs_set_dir_name_len(leaf, dir_item, name_len);
163 btrfs_set_dir_transid(leaf, dir_item, trans->transid);
164 name_ptr = (unsigned long)(dir_item + 1);
165
166 write_extent_buffer(leaf, name, name_ptr, name_len);
167 btrfs_mark_buffer_dirty(leaf);
168
169 second_insert:
170 /* FIXME, use some real flag for selecting the extra index */
171 if (root == root->fs_info->tree_root) {
172 ret = 0;
173 goto out_free;
174 }
175 btrfs_release_path(root, path);
176
177 btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
178 key.offset = index;
179 dir_item = insert_with_overflow(trans, root, path, &key, data_size,
180 name, name_len);
181 if (IS_ERR(dir_item)) {
182 ret2 = PTR_ERR(dir_item);
183 goto out_free;
184 }
185 leaf = path->nodes[0];
186 btrfs_cpu_key_to_disk(&disk_key, location);
187 btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
188 btrfs_set_dir_type(leaf, dir_item, type);
189 btrfs_set_dir_data_len(leaf, dir_item, 0);
190 btrfs_set_dir_name_len(leaf, dir_item, name_len);
191 btrfs_set_dir_transid(leaf, dir_item, trans->transid);
192 name_ptr = (unsigned long)(dir_item + 1);
193 write_extent_buffer(leaf, name, name_ptr, name_len);
194 btrfs_mark_buffer_dirty(leaf);
195
196 out_free:
197
198 btrfs_free_path(path);
199 if (ret)
200 return ret;
201 if (ret2)
202 return ret2;
203 return 0;
204 }
205
206 /*
207 * lookup a directory item based on name. 'dir' is the objectid
208 * we're searching in, and 'mod' tells us if you plan on deleting the
209 * item (use mod < 0) or changing the options (use mod > 0)
210 */
btrfs_lookup_dir_item(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_path * path,u64 dir,const char * name,int name_len,int mod)211 struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
212 struct btrfs_root *root,
213 struct btrfs_path *path, u64 dir,
214 const char *name, int name_len,
215 int mod)
216 {
217 int ret;
218 struct btrfs_key key;
219 int ins_len = mod < 0 ? -1 : 0;
220 int cow = mod != 0;
221 struct btrfs_key found_key;
222 struct extent_buffer *leaf;
223
224 key.objectid = dir;
225 btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
226
227 key.offset = btrfs_name_hash(name, name_len);
228
229 ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
230 if (ret < 0)
231 return ERR_PTR(ret);
232 if (ret > 0) {
233 if (path->slots[0] == 0)
234 return NULL;
235 path->slots[0]--;
236 }
237
238 leaf = path->nodes[0];
239 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
240
241 if (found_key.objectid != dir ||
242 btrfs_key_type(&found_key) != BTRFS_DIR_ITEM_KEY ||
243 found_key.offset != key.offset)
244 return NULL;
245
246 return btrfs_match_dir_item_name(root, path, name, name_len);
247 }
248
249 /*
250 * lookup a directory item based on index. 'dir' is the objectid
251 * we're searching in, and 'mod' tells us if you plan on deleting the
252 * item (use mod < 0) or changing the options (use mod > 0)
253 *
254 * The name is used to make sure the index really points to the name you were
255 * looking for.
256 */
257 struct btrfs_dir_item *
btrfs_lookup_dir_index_item(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_path * path,u64 dir,u64 objectid,const char * name,int name_len,int mod)258 btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
259 struct btrfs_root *root,
260 struct btrfs_path *path, u64 dir,
261 u64 objectid, const char *name, int name_len,
262 int mod)
263 {
264 int ret;
265 struct btrfs_key key;
266 int ins_len = mod < 0 ? -1 : 0;
267 int cow = mod != 0;
268
269 key.objectid = dir;
270 btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
271 key.offset = objectid;
272
273 ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
274 if (ret < 0)
275 return ERR_PTR(ret);
276 if (ret > 0)
277 return ERR_PTR(-ENOENT);
278 return btrfs_match_dir_item_name(root, path, name, name_len);
279 }
280
281 struct btrfs_dir_item *
btrfs_search_dir_index_item(struct btrfs_root * root,struct btrfs_path * path,u64 dirid,const char * name,int name_len)282 btrfs_search_dir_index_item(struct btrfs_root *root,
283 struct btrfs_path *path, u64 dirid,
284 const char *name, int name_len)
285 {
286 struct extent_buffer *leaf;
287 struct btrfs_dir_item *di;
288 struct btrfs_key key;
289 u32 nritems;
290 int ret;
291
292 key.objectid = dirid;
293 key.type = BTRFS_DIR_INDEX_KEY;
294 key.offset = 0;
295
296 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
297 if (ret < 0)
298 return ERR_PTR(ret);
299
300 leaf = path->nodes[0];
301 nritems = btrfs_header_nritems(leaf);
302
303 while (1) {
304 if (path->slots[0] >= nritems) {
305 ret = btrfs_next_leaf(root, path);
306 if (ret < 0)
307 return ERR_PTR(ret);
308 if (ret > 0)
309 break;
310 leaf = path->nodes[0];
311 nritems = btrfs_header_nritems(leaf);
312 continue;
313 }
314
315 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
316 if (key.objectid != dirid || key.type != BTRFS_DIR_INDEX_KEY)
317 break;
318
319 di = btrfs_match_dir_item_name(root, path, name, name_len);
320 if (di)
321 return di;
322
323 path->slots[0]++;
324 }
325 return NULL;
326 }
327
btrfs_lookup_xattr(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_path * path,u64 dir,const char * name,u16 name_len,int mod)328 struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,
329 struct btrfs_root *root,
330 struct btrfs_path *path, u64 dir,
331 const char *name, u16 name_len,
332 int mod)
333 {
334 int ret;
335 struct btrfs_key key;
336 int ins_len = mod < 0 ? -1 : 0;
337 int cow = mod != 0;
338 struct btrfs_key found_key;
339 struct extent_buffer *leaf;
340
341 key.objectid = dir;
342 btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
343 key.offset = btrfs_name_hash(name, name_len);
344 ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
345 if (ret < 0)
346 return ERR_PTR(ret);
347 if (ret > 0) {
348 if (path->slots[0] == 0)
349 return NULL;
350 path->slots[0]--;
351 }
352
353 leaf = path->nodes[0];
354 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
355
356 if (found_key.objectid != dir ||
357 btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY ||
358 found_key.offset != key.offset)
359 return NULL;
360
361 return btrfs_match_dir_item_name(root, path, name, name_len);
362 }
363
364 /*
365 * helper function to look at the directory item pointed to by 'path'
366 * this walks through all the entries in a dir item and finds one
367 * for a specific name.
368 */
btrfs_match_dir_item_name(struct btrfs_root * root,struct btrfs_path * path,const char * name,int name_len)369 struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
370 struct btrfs_path *path,
371 const char *name, int name_len)
372 {
373 struct btrfs_dir_item *dir_item;
374 unsigned long name_ptr;
375 u32 total_len;
376 u32 cur = 0;
377 u32 this_len;
378 struct extent_buffer *leaf;
379
380 leaf = path->nodes[0];
381 dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
382 if (verify_dir_item(root, leaf, dir_item))
383 return NULL;
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 */
btrfs_delete_one_dir_name(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_path * path,struct btrfs_dir_item * di)407 int 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 ret = btrfs_truncate_item(trans, root, path,
433 item_len - sub_item_len, 1);
434 }
435 return ret;
436 }
437
verify_dir_item(struct btrfs_root * root,struct extent_buffer * leaf,struct btrfs_dir_item * dir_item)438 int verify_dir_item(struct btrfs_root *root,
439 struct extent_buffer *leaf,
440 struct btrfs_dir_item *dir_item)
441 {
442 u16 namelen = BTRFS_NAME_LEN;
443 u8 type = btrfs_dir_type(leaf, dir_item);
444
445 if (type >= BTRFS_FT_MAX) {
446 printk(KERN_CRIT "btrfs: invalid dir item type: %d\n",
447 (int)type);
448 return 1;
449 }
450
451 if (type == BTRFS_FT_XATTR)
452 namelen = XATTR_NAME_MAX;
453
454 if (btrfs_dir_name_len(leaf, dir_item) > namelen) {
455 printk(KERN_CRIT "btrfS: invalid dir item name len: %u\n",
456 (unsigned)btrfs_dir_data_len(leaf, dir_item));
457 return 1;
458 }
459
460 /* BTRFS_MAX_XATTR_SIZE is the same for all dir items */
461 if (btrfs_dir_data_len(leaf, dir_item) > BTRFS_MAX_XATTR_SIZE(root)) {
462 printk(KERN_CRIT "btrfs: invalid dir item data len: %u\n",
463 (unsigned)btrfs_dir_data_len(leaf, dir_item));
464 return 1;
465 }
466
467 return 0;
468 }
469