mm: fix exec activate_mm vs TLB shootdown and lazy tlb switching race
[linux/fpc-iii.git] / fs / btrfs / dir-item.c
blob41cb9196eaa82c553fc16fafc331bf37eb294c7e
1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
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.
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.
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.
19 #include "ctree.h"
20 #include "disk-io.h"
21 #include "hash.h"
22 #include "transaction.h"
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.
30 * The name is not copied into the dir item, you have to do that yourself.
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)
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;
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;
66 * xattrs work a lot like directories, this inserts an xattr item
67 * into the tree
69 int 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)
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;
83 if (name_len + data_len > BTRFS_MAX_XATTR_SIZE(root->fs_info))
84 return -ENOSPC;
86 key.objectid = objectid;
87 key.type = BTRFS_XATTR_ITEM_KEY;
88 key.offset = btrfs_name_hash(name, name_len);
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 if (IS_ERR(dir_item))
94 return PTR_ERR(dir_item);
95 memset(&location, 0, sizeof(location));
97 leaf = path->nodes[0];
98 btrfs_cpu_key_to_disk(&disk_key, &location);
99 btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
100 btrfs_set_dir_type(leaf, dir_item, BTRFS_FT_XATTR);
101 btrfs_set_dir_name_len(leaf, dir_item, name_len);
102 btrfs_set_dir_transid(leaf, dir_item, trans->transid);
103 btrfs_set_dir_data_len(leaf, dir_item, data_len);
104 name_ptr = (unsigned long)(dir_item + 1);
105 data_ptr = (unsigned long)((char *)name_ptr + name_len);
107 write_extent_buffer(leaf, name, name_ptr, name_len);
108 write_extent_buffer(leaf, data, data_ptr, data_len);
109 btrfs_mark_buffer_dirty(path->nodes[0]);
111 return ret;
115 * insert a directory item in the tree, doing all the magic for
116 * both indexes. 'dir' indicates which objectid to insert it into,
117 * 'location' is the key to stuff into the directory item, 'type' is the
118 * type of the inode we're pointing to, and 'index' is the sequence number
119 * to use for the second index (if one is created).
120 * Will return 0 or -ENOMEM
122 int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
123 *root, const char *name, int name_len,
124 struct btrfs_inode *dir, struct btrfs_key *location,
125 u8 type, u64 index)
127 int ret = 0;
128 int ret2 = 0;
129 struct btrfs_path *path;
130 struct btrfs_dir_item *dir_item;
131 struct extent_buffer *leaf;
132 unsigned long name_ptr;
133 struct btrfs_key key;
134 struct btrfs_disk_key disk_key;
135 u32 data_size;
137 key.objectid = btrfs_ino(dir);
138 key.type = BTRFS_DIR_ITEM_KEY;
139 key.offset = btrfs_name_hash(name, name_len);
141 path = btrfs_alloc_path();
142 if (!path)
143 return -ENOMEM;
144 path->leave_spinning = 1;
146 btrfs_cpu_key_to_disk(&disk_key, location);
148 data_size = sizeof(*dir_item) + name_len;
149 dir_item = insert_with_overflow(trans, root, path, &key, data_size,
150 name, name_len);
151 if (IS_ERR(dir_item)) {
152 ret = PTR_ERR(dir_item);
153 if (ret == -EEXIST)
154 goto second_insert;
155 goto out_free;
158 leaf = path->nodes[0];
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);
166 write_extent_buffer(leaf, name, name_ptr, name_len);
167 btrfs_mark_buffer_dirty(leaf);
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;
175 btrfs_release_path(path);
177 ret2 = btrfs_insert_delayed_dir_index(trans, root->fs_info, name,
178 name_len, dir, &disk_key, type, index);
179 out_free:
180 btrfs_free_path(path);
181 if (ret)
182 return ret;
183 if (ret2)
184 return ret2;
185 return 0;
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)
193 struct 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)
199 int ret;
200 struct btrfs_key key;
201 int ins_len = mod < 0 ? -1 : 0;
202 int cow = mod != 0;
204 key.objectid = dir;
205 key.type = BTRFS_DIR_ITEM_KEY;
207 key.offset = btrfs_name_hash(name, name_len);
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;
215 return btrfs_match_dir_item_name(root->fs_info, path, name, name_len);
218 int btrfs_check_dir_item_collision(struct btrfs_root *root, u64 dir,
219 const char *name, int name_len)
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;
230 path = btrfs_alloc_path();
231 if (!path)
232 return -ENOMEM;
234 key.objectid = dir;
235 key.type = BTRFS_DIR_ITEM_KEY;
236 key.offset = btrfs_name_hash(name, name_len);
238 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
240 /* return back any errors */
241 if (ret < 0)
242 goto out;
244 /* nothing found, we're safe */
245 if (ret > 0) {
246 ret = 0;
247 goto out;
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;
259 * see if there is room in the item to insert this
260 * name
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;
272 out:
273 btrfs_free_path(path);
274 return ret;
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)
282 * The name is used to make sure the index really points to the name you were
283 * looking for.
285 struct btrfs_dir_item *
286 btrfs_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)
292 int ret;
293 struct btrfs_key key;
294 int ins_len = mod < 0 ? -1 : 0;
295 int cow = mod != 0;
297 key.objectid = dir;
298 key.type = BTRFS_DIR_INDEX_KEY;
299 key.offset = objectid;
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);
309 struct btrfs_dir_item *
310 btrfs_search_dir_index_item(struct btrfs_root *root,
311 struct btrfs_path *path, u64 dirid,
312 const char *name, int name_len)
314 struct extent_buffer *leaf;
315 struct btrfs_dir_item *di;
316 struct btrfs_key key;
317 u32 nritems;
318 int ret;
320 key.objectid = dirid;
321 key.type = BTRFS_DIR_INDEX_KEY;
322 key.offset = 0;
324 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
325 if (ret < 0)
326 return ERR_PTR(ret);
328 leaf = path->nodes[0];
329 nritems = btrfs_header_nritems(leaf);
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;
343 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
344 if (key.objectid != dirid || key.type != BTRFS_DIR_INDEX_KEY)
345 break;
347 di = btrfs_match_dir_item_name(root->fs_info, path,
348 name, name_len);
349 if (di)
350 return di;
352 path->slots[0]++;
354 return NULL;
357 struct 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)
363 int ret;
364 struct btrfs_key key;
365 int ins_len = mod < 0 ? -1 : 0;
366 int cow = mod != 0;
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;
377 return btrfs_match_dir_item_name(root->fs_info, path, name, name_len);
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.
385 struct 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)
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;
396 leaf = path->nodes[0];
397 dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
399 total_len = btrfs_item_size_nr(leaf, path->slots[0]);
400 while (cur < total_len) {
401 this_len = sizeof(*dir_item) +
402 btrfs_dir_name_len(leaf, dir_item) +
403 btrfs_dir_data_len(leaf, dir_item);
404 name_ptr = (unsigned long)(dir_item + 1);
406 if (verify_dir_item(fs_info, leaf, path->slots[0], dir_item))
407 return NULL;
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;
412 cur += this_len;
413 dir_item = (struct btrfs_dir_item *)((char *)dir_item +
414 this_len);
416 return NULL;
420 * given a pointer into a directory item, delete it. This
421 * handles items that have more than one entry in them.
423 int 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)
429 struct extent_buffer *leaf;
430 u32 sub_item_len;
431 u32 item_len;
432 int ret = 0;
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;
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);
451 return ret;
454 int verify_dir_item(struct btrfs_fs_info *fs_info,
455 struct extent_buffer *leaf,
456 int slot,
457 struct btrfs_dir_item *dir_item)
459 u16 namelen = BTRFS_NAME_LEN;
460 int ret;
461 u8 type = btrfs_dir_type(leaf, dir_item);
463 if (type >= BTRFS_FT_MAX) {
464 btrfs_crit(fs_info, "invalid dir item type: %d", (int)type);
465 return 1;
468 if (type == BTRFS_FT_XATTR)
469 namelen = XATTR_NAME_MAX;
471 if (btrfs_dir_name_len(leaf, dir_item) > namelen) {
472 btrfs_crit(fs_info, "invalid dir item name len: %u",
473 (unsigned)btrfs_dir_name_len(leaf, dir_item));
474 return 1;
477 namelen = btrfs_dir_name_len(leaf, dir_item);
478 ret = btrfs_is_name_len_valid(leaf, slot,
479 (unsigned long)(dir_item + 1), namelen);
480 if (!ret)
481 return 1;
483 /* BTRFS_MAX_XATTR_SIZE is the same for all dir items */
484 if ((btrfs_dir_data_len(leaf, dir_item) +
485 btrfs_dir_name_len(leaf, dir_item)) >
486 BTRFS_MAX_XATTR_SIZE(fs_info)) {
487 btrfs_crit(fs_info, "invalid dir item name + data len: %u + %u",
488 (unsigned)btrfs_dir_name_len(leaf, dir_item),
489 (unsigned)btrfs_dir_data_len(leaf, dir_item));
490 return 1;
493 return 0;
496 bool btrfs_is_name_len_valid(struct extent_buffer *leaf, int slot,
497 unsigned long start, u16 name_len)
499 struct btrfs_fs_info *fs_info = leaf->fs_info;
500 struct btrfs_key key;
501 u32 read_start;
502 u32 read_end;
503 u32 item_start;
504 u32 item_end;
505 u32 size;
506 bool ret = true;
508 ASSERT(start > BTRFS_LEAF_DATA_OFFSET);
510 read_start = start - BTRFS_LEAF_DATA_OFFSET;
511 read_end = read_start + name_len;
512 item_start = btrfs_item_offset_nr(leaf, slot);
513 item_end = btrfs_item_end_nr(leaf, slot);
515 btrfs_item_key_to_cpu(leaf, &key, slot);
517 switch (key.type) {
518 case BTRFS_DIR_ITEM_KEY:
519 case BTRFS_XATTR_ITEM_KEY:
520 case BTRFS_DIR_INDEX_KEY:
521 size = sizeof(struct btrfs_dir_item);
522 break;
523 case BTRFS_INODE_REF_KEY:
524 size = sizeof(struct btrfs_inode_ref);
525 break;
526 case BTRFS_INODE_EXTREF_KEY:
527 size = sizeof(struct btrfs_inode_extref);
528 break;
529 case BTRFS_ROOT_REF_KEY:
530 case BTRFS_ROOT_BACKREF_KEY:
531 size = sizeof(struct btrfs_root_ref);
532 break;
533 default:
534 ret = false;
535 goto out;
538 if (read_start < item_start) {
539 ret = false;
540 goto out;
542 if (read_end > item_end) {
543 ret = false;
544 goto out;
547 /* there shall be item(s) before name */
548 if (read_start - item_start < size) {
549 ret = false;
550 goto out;
553 out:
554 if (!ret)
555 btrfs_crit(fs_info, "invalid dir item name len: %u",
556 (unsigned int)name_len);
557 return ret;