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,const char * name,u16 name_len,const void * data,u16 data_len,u64 dir)70 int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,
71 struct btrfs_root *root, const char *name,
72 u16 name_len, const void *data, u16 data_len,
73 u64 dir)
74 {
75 int ret = 0;
76 struct btrfs_path *path;
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 key.objectid = dir;
85 btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
86 key.offset = btrfs_name_hash(name, name_len);
87 path = btrfs_alloc_path();
88 if (!path)
89 return -ENOMEM;
90 if (name_len + data_len + sizeof(struct btrfs_dir_item) >
91 BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item))
92 return -ENOSPC;
93
94 data_size = sizeof(*dir_item) + name_len + data_len;
95 dir_item = insert_with_overflow(trans, root, path, &key, data_size,
96 name, name_len);
97 /*
98 * FIXME: at some point we should handle xattr's that are larger than
99 * what we can fit in our leaf. We set location to NULL b/c we arent
100 * pointing at anything else, that will change if we store the xattr
101 * data in a separate inode.
102 */
103 BUG_ON(IS_ERR(dir_item));
104 memset(&location, 0, sizeof(location));
105
106 leaf = path->nodes[0];
107 btrfs_cpu_key_to_disk(&disk_key, &location);
108 btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
109 btrfs_set_dir_type(leaf, dir_item, BTRFS_FT_XATTR);
110 btrfs_set_dir_name_len(leaf, dir_item, name_len);
111 btrfs_set_dir_transid(leaf, dir_item, trans->transid);
112 btrfs_set_dir_data_len(leaf, dir_item, data_len);
113 name_ptr = (unsigned long)(dir_item + 1);
114 data_ptr = (unsigned long)((char *)name_ptr + name_len);
115
116 write_extent_buffer(leaf, name, name_ptr, name_len);
117 write_extent_buffer(leaf, data, data_ptr, data_len);
118 btrfs_mark_buffer_dirty(path->nodes[0]);
119
120 btrfs_free_path(path);
121 return ret;
122 }
123
124 /*
125 * insert a directory item in the tree, doing all the magic for
126 * both indexes. 'dir' indicates which objectid to insert it into,
127 * 'location' is the key to stuff into the directory item, 'type' is the
128 * type of the inode we're pointing to, and 'index' is the sequence number
129 * to use for the second index (if one is created).
130 */
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)131 int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
132 *root, const char *name, int name_len, u64 dir,
133 struct btrfs_key *location, u8 type, u64 index)
134 {
135 int ret = 0;
136 int ret2 = 0;
137 struct btrfs_path *path;
138 struct btrfs_dir_item *dir_item;
139 struct extent_buffer *leaf;
140 unsigned long name_ptr;
141 struct btrfs_key key;
142 struct btrfs_disk_key disk_key;
143 u32 data_size;
144
145 key.objectid = dir;
146 btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
147 key.offset = btrfs_name_hash(name, name_len);
148 path = btrfs_alloc_path();
149 data_size = sizeof(*dir_item) + name_len;
150 dir_item = insert_with_overflow(trans, root, path, &key, data_size,
151 name, name_len);
152 if (IS_ERR(dir_item)) {
153 ret = PTR_ERR(dir_item);
154 if (ret == -EEXIST)
155 goto second_insert;
156 goto out;
157 }
158
159 leaf = path->nodes[0];
160 btrfs_cpu_key_to_disk(&disk_key, location);
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
171 second_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;
176 }
177 btrfs_release_path(root, path);
178
179 btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
180 key.offset = index;
181 dir_item = insert_with_overflow(trans, root, path, &key, data_size,
182 name, name_len);
183 if (IS_ERR(dir_item)) {
184 ret2 = PTR_ERR(dir_item);
185 goto out;
186 }
187 leaf = path->nodes[0];
188 btrfs_cpu_key_to_disk(&disk_key, location);
189 btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
190 btrfs_set_dir_type(leaf, dir_item, type);
191 btrfs_set_dir_data_len(leaf, dir_item, 0);
192 btrfs_set_dir_name_len(leaf, dir_item, name_len);
193 btrfs_set_dir_transid(leaf, dir_item, trans->transid);
194 name_ptr = (unsigned long)(dir_item + 1);
195 write_extent_buffer(leaf, name, name_ptr, name_len);
196 btrfs_mark_buffer_dirty(leaf);
197 out:
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
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)281 struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,
282 struct btrfs_root *root,
283 struct btrfs_path *path, u64 dir,
284 const char *name, u16 name_len,
285 int mod)
286 {
287 int ret;
288 struct btrfs_key key;
289 int ins_len = mod < 0 ? -1 : 0;
290 int cow = mod != 0;
291 struct btrfs_key found_key;
292 struct extent_buffer *leaf;
293
294 key.objectid = dir;
295 btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
296 key.offset = btrfs_name_hash(name, name_len);
297 ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
298 if (ret < 0)
299 return ERR_PTR(ret);
300 if (ret > 0) {
301 if (path->slots[0] == 0)
302 return NULL;
303 path->slots[0]--;
304 }
305
306 leaf = path->nodes[0];
307 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
308
309 if (found_key.objectid != dir ||
310 btrfs_key_type(&found_key) != BTRFS_XATTR_ITEM_KEY ||
311 found_key.offset != key.offset)
312 return NULL;
313
314 return btrfs_match_dir_item_name(root, path, name, name_len);
315 }
316
317 /*
318 * helper function to look at the directory item pointed to by 'path'
319 * this walks through all the entries in a dir item and finds one
320 * for a specific name.
321 */
btrfs_match_dir_item_name(struct btrfs_root * root,struct btrfs_path * path,const char * name,int name_len)322 struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
323 struct btrfs_path *path,
324 const char *name, int name_len)
325 {
326 struct btrfs_dir_item *dir_item;
327 unsigned long name_ptr;
328 u32 total_len;
329 u32 cur = 0;
330 u32 this_len;
331 struct extent_buffer *leaf;
332
333 leaf = path->nodes[0];
334 dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
335 total_len = btrfs_item_size_nr(leaf, path->slots[0]);
336 while (cur < total_len) {
337 this_len = sizeof(*dir_item) +
338 btrfs_dir_name_len(leaf, dir_item) +
339 btrfs_dir_data_len(leaf, dir_item);
340 name_ptr = (unsigned long)(dir_item + 1);
341
342 if (btrfs_dir_name_len(leaf, dir_item) == name_len &&
343 memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
344 return dir_item;
345
346 cur += this_len;
347 dir_item = (struct btrfs_dir_item *)((char *)dir_item +
348 this_len);
349 }
350 return NULL;
351 }
352
353 /*
354 * given a pointer into a directory item, delete it. This
355 * handles items that have more than one entry in them.
356 */
btrfs_delete_one_dir_name(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_path * path,struct btrfs_dir_item * di)357 int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
358 struct btrfs_root *root,
359 struct btrfs_path *path,
360 struct btrfs_dir_item *di)
361 {
362
363 struct extent_buffer *leaf;
364 u32 sub_item_len;
365 u32 item_len;
366 int ret = 0;
367
368 leaf = path->nodes[0];
369 sub_item_len = sizeof(*di) + btrfs_dir_name_len(leaf, di) +
370 btrfs_dir_data_len(leaf, di);
371 item_len = btrfs_item_size_nr(leaf, path->slots[0]);
372 if (sub_item_len == item_len) {
373 ret = btrfs_del_item(trans, root, path);
374 } else {
375 /* MARKER */
376 unsigned long ptr = (unsigned long)di;
377 unsigned long start;
378
379 start = btrfs_item_ptr_offset(leaf, path->slots[0]);
380 memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
381 item_len - (ptr + sub_item_len - start));
382 ret = btrfs_truncate_item(trans, root, path,
383 item_len - sub_item_len, 1);
384 }
385 return 0;
386 }
387