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ef8809c1e69c3896655a64ee43d6713f7fc1f3ab
[deliverable/linux.git] / fs / btrfs / ctree.c
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 <linux/sched.h>
20 #include "ctree.h"
21 #include "disk-io.h"
22 #include "transaction.h"
23 #include "print-tree.h"
24
25 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
26 *root, struct btrfs_path *path, int level);
27 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
28 *root, struct btrfs_key *ins_key,
29 struct btrfs_path *path, int data_size, int extend);
30 static int push_node_left(struct btrfs_trans_handle *trans,
31 struct btrfs_root *root, struct extent_buffer *dst,
32 struct extent_buffer *src);
33 static int balance_node_right(struct btrfs_trans_handle *trans,
34 struct btrfs_root *root,
35 struct extent_buffer *dst_buf,
36 struct extent_buffer *src_buf);
37 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
38 struct btrfs_path *path, int level, int slot);
39
40 inline void btrfs_init_path(struct btrfs_path *p)
41 {
42 memset(p, 0, sizeof(*p));
43 }
44
45 struct btrfs_path *btrfs_alloc_path(void)
46 {
47 struct btrfs_path *path;
48 path = kmem_cache_alloc(btrfs_path_cachep, GFP_NOFS);
49 if (path) {
50 btrfs_init_path(path);
51 path->reada = 1;
52 }
53 return path;
54 }
55
56 void btrfs_free_path(struct btrfs_path *p)
57 {
58 btrfs_release_path(NULL, p);
59 kmem_cache_free(btrfs_path_cachep, p);
60 }
61
62 void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
63 {
64 int i;
65 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
66 if (!p->nodes[i])
67 break;
68 free_extent_buffer(p->nodes[i]);
69 }
70 memset(p, 0, sizeof(*p));
71 }
72
73 int btrfs_copy_root(struct btrfs_trans_handle *trans,
74 struct btrfs_root *root,
75 struct extent_buffer *buf,
76 struct extent_buffer **cow_ret, u64 new_root_objectid)
77 {
78 struct extent_buffer *cow;
79 u32 nritems;
80 int ret = 0;
81 int level;
82 struct btrfs_key first_key;
83 struct btrfs_root *new_root;
84
85 new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
86 if (!new_root)
87 return -ENOMEM;
88
89 memcpy(new_root, root, sizeof(*new_root));
90 new_root->root_key.objectid = new_root_objectid;
91
92 WARN_ON(root->ref_cows && trans->transid !=
93 root->fs_info->running_transaction->transid);
94 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
95
96 level = btrfs_header_level(buf);
97 nritems = btrfs_header_nritems(buf);
98 if (nritems) {
99 if (level == 0)
100 btrfs_item_key_to_cpu(buf, &first_key, 0);
101 else
102 btrfs_node_key_to_cpu(buf, &first_key, 0);
103 } else {
104 first_key.objectid = 0;
105 }
106 cow = __btrfs_alloc_free_block(trans, new_root, buf->len,
107 new_root_objectid,
108 trans->transid, first_key.objectid,
109 level, buf->start, 0);
110 if (IS_ERR(cow)) {
111 kfree(new_root);
112 return PTR_ERR(cow);
113 }
114
115 copy_extent_buffer(cow, buf, 0, 0, cow->len);
116 btrfs_set_header_bytenr(cow, cow->start);
117 btrfs_set_header_generation(cow, trans->transid);
118 btrfs_set_header_owner(cow, new_root_objectid);
119
120 WARN_ON(btrfs_header_generation(buf) > trans->transid);
121 ret = btrfs_inc_ref(trans, new_root, buf);
122 kfree(new_root);
123
124 if (ret)
125 return ret;
126
127 btrfs_mark_buffer_dirty(cow);
128 *cow_ret = cow;
129 return 0;
130 }
131
132 int __btrfs_cow_block(struct btrfs_trans_handle *trans,
133 struct btrfs_root *root,
134 struct extent_buffer *buf,
135 struct extent_buffer *parent, int parent_slot,
136 struct extent_buffer **cow_ret,
137 u64 search_start, u64 empty_size)
138 {
139 u64 root_gen;
140 struct extent_buffer *cow;
141 u32 nritems;
142 int ret = 0;
143 int different_trans = 0;
144 int level;
145 struct btrfs_key first_key;
146
147 if (root->ref_cows) {
148 root_gen = trans->transid;
149 } else {
150 root_gen = 0;
151 }
152
153 WARN_ON(root->ref_cows && trans->transid !=
154 root->fs_info->running_transaction->transid);
155 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
156
157 level = btrfs_header_level(buf);
158 nritems = btrfs_header_nritems(buf);
159 if (nritems) {
160 if (level == 0)
161 btrfs_item_key_to_cpu(buf, &first_key, 0);
162 else
163 btrfs_node_key_to_cpu(buf, &first_key, 0);
164 } else {
165 first_key.objectid = 0;
166 }
167 cow = __btrfs_alloc_free_block(trans, root, buf->len,
168 root->root_key.objectid,
169 root_gen, first_key.objectid, level,
170 search_start, empty_size);
171 if (IS_ERR(cow))
172 return PTR_ERR(cow);
173
174 copy_extent_buffer(cow, buf, 0, 0, cow->len);
175 btrfs_set_header_bytenr(cow, cow->start);
176 btrfs_set_header_generation(cow, trans->transid);
177 btrfs_set_header_owner(cow, root->root_key.objectid);
178
179 WARN_ON(btrfs_header_generation(buf) > trans->transid);
180 if (btrfs_header_generation(buf) != trans->transid) {
181 different_trans = 1;
182 ret = btrfs_inc_ref(trans, root, buf);
183 if (ret)
184 return ret;
185 } else {
186 clean_tree_block(trans, root, buf);
187 }
188
189 if (buf == root->node) {
190 root_gen = btrfs_header_generation(buf);
191 root->node = cow;
192 extent_buffer_get(cow);
193 if (buf != root->commit_root) {
194 btrfs_free_extent(trans, root, buf->start,
195 buf->len, root->root_key.objectid,
196 root_gen, 0, 0, 1);
197 }
198 free_extent_buffer(buf);
199 } else {
200 root_gen = btrfs_header_generation(parent);
201 btrfs_set_node_blockptr(parent, parent_slot,
202 cow->start);
203 WARN_ON(trans->transid == 0);
204 btrfs_set_node_ptr_generation(parent, parent_slot,
205 trans->transid);
206 btrfs_mark_buffer_dirty(parent);
207 WARN_ON(btrfs_header_generation(parent) != trans->transid);
208 btrfs_free_extent(trans, root, buf->start, buf->len,
209 btrfs_header_owner(parent), root_gen,
210 0, 0, 1);
211 }
212 free_extent_buffer(buf);
213 btrfs_mark_buffer_dirty(cow);
214 *cow_ret = cow;
215 return 0;
216 }
217
218 int btrfs_cow_block(struct btrfs_trans_handle *trans,
219 struct btrfs_root *root, struct extent_buffer *buf,
220 struct extent_buffer *parent, int parent_slot,
221 struct extent_buffer **cow_ret)
222 {
223 u64 search_start;
224 u64 header_trans;
225 int ret;
226
227 if (trans->transaction != root->fs_info->running_transaction) {
228 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
229 root->fs_info->running_transaction->transid);
230 WARN_ON(1);
231 }
232 if (trans->transid != root->fs_info->generation) {
233 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
234 root->fs_info->generation);
235 WARN_ON(1);
236 }
237
238 header_trans = btrfs_header_generation(buf);
239 if (header_trans == trans->transid) {
240 *cow_ret = buf;
241 return 0;
242 }
243
244 search_start = buf->start & ~((u64)BTRFS_BLOCK_GROUP_SIZE - 1);
245 ret = __btrfs_cow_block(trans, root, buf, parent,
246 parent_slot, cow_ret, search_start, 0);
247 return ret;
248 }
249
250 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
251 {
252 if (blocknr < other && other - (blocknr + blocksize) < 32768)
253 return 1;
254 if (blocknr > other && blocknr - (other + blocksize) < 32768)
255 return 1;
256 return 0;
257 }
258
259 /*
260 * compare two keys in a memcmp fashion
261 */
262 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
263 {
264 struct btrfs_key k1;
265
266 btrfs_disk_key_to_cpu(&k1, disk);
267
268 if (k1.objectid > k2->objectid)
269 return 1;
270 if (k1.objectid < k2->objectid)
271 return -1;
272 if (k1.type > k2->type)
273 return 1;
274 if (k1.type < k2->type)
275 return -1;
276 if (k1.offset > k2->offset)
277 return 1;
278 if (k1.offset < k2->offset)
279 return -1;
280 return 0;
281 }
282
283
284 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
285 struct btrfs_root *root, struct extent_buffer *parent,
286 int start_slot, int cache_only, u64 *last_ret,
287 struct btrfs_key *progress)
288 {
289 struct extent_buffer *cur;
290 struct extent_buffer *tmp;
291 u64 blocknr;
292 u64 search_start = *last_ret;
293 u64 last_block = 0;
294 u64 other;
295 u32 parent_nritems;
296 int end_slot;
297 int i;
298 int err = 0;
299 int parent_level;
300 int uptodate;
301 u32 blocksize;
302 int progress_passed = 0;
303 struct btrfs_disk_key disk_key;
304
305 parent_level = btrfs_header_level(parent);
306 if (cache_only && parent_level != 1)
307 return 0;
308
309 if (trans->transaction != root->fs_info->running_transaction) {
310 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
311 root->fs_info->running_transaction->transid);
312 WARN_ON(1);
313 }
314 if (trans->transid != root->fs_info->generation) {
315 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
316 root->fs_info->generation);
317 WARN_ON(1);
318 }
319
320 parent_nritems = btrfs_header_nritems(parent);
321 blocksize = btrfs_level_size(root, parent_level - 1);
322 end_slot = parent_nritems;
323
324 if (parent_nritems == 1)
325 return 0;
326
327 for (i = start_slot; i < end_slot; i++) {
328 int close = 1;
329
330 if (!parent->map_token) {
331 map_extent_buffer(parent,
332 btrfs_node_key_ptr_offset(i),
333 sizeof(struct btrfs_key_ptr),
334 &parent->map_token, &parent->kaddr,
335 &parent->map_start, &parent->map_len,
336 KM_USER1);
337 }
338 btrfs_node_key(parent, &disk_key, i);
339 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
340 continue;
341
342 progress_passed = 1;
343 blocknr = btrfs_node_blockptr(parent, i);
344 if (last_block == 0)
345 last_block = blocknr;
346
347 if (i > 0) {
348 other = btrfs_node_blockptr(parent, i - 1);
349 close = close_blocks(blocknr, other, blocksize);
350 }
351 if (close && i < end_slot - 2) {
352 other = btrfs_node_blockptr(parent, i + 1);
353 close = close_blocks(blocknr, other, blocksize);
354 }
355 if (close) {
356 last_block = blocknr;
357 continue;
358 }
359 if (parent->map_token) {
360 unmap_extent_buffer(parent, parent->map_token,
361 KM_USER1);
362 parent->map_token = NULL;
363 }
364
365 cur = btrfs_find_tree_block(root, blocknr, blocksize);
366 if (cur)
367 uptodate = btrfs_buffer_uptodate(cur);
368 else
369 uptodate = 0;
370 if (!cur || !uptodate) {
371 if (cache_only) {
372 free_extent_buffer(cur);
373 continue;
374 }
375 if (!cur) {
376 cur = read_tree_block(root, blocknr,
377 blocksize);
378 } else if (!uptodate) {
379 btrfs_read_buffer(cur);
380 }
381 }
382 if (search_start == 0)
383 search_start = last_block;
384
385 err = __btrfs_cow_block(trans, root, cur, parent, i,
386 &tmp, search_start,
387 min(16 * blocksize,
388 (end_slot - i) * blocksize));
389 if (err) {
390 free_extent_buffer(cur);
391 break;
392 }
393 search_start = tmp->start;
394 last_block = tmp->start;
395 *last_ret = search_start;
396 if (parent_level == 1)
397 btrfs_clear_buffer_defrag(tmp);
398 free_extent_buffer(tmp);
399 }
400 if (parent->map_token) {
401 unmap_extent_buffer(parent, parent->map_token,
402 KM_USER1);
403 parent->map_token = NULL;
404 }
405 return err;
406 }
407
408 /*
409 * The leaf data grows from end-to-front in the node.
410 * this returns the address of the start of the last item,
411 * which is the stop of the leaf data stack
412 */
413 static inline unsigned int leaf_data_end(struct btrfs_root *root,
414 struct extent_buffer *leaf)
415 {
416 u32 nr = btrfs_header_nritems(leaf);
417 if (nr == 0)
418 return BTRFS_LEAF_DATA_SIZE(root);
419 return btrfs_item_offset_nr(leaf, nr - 1);
420 }
421
422 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
423 int level)
424 {
425 struct extent_buffer *parent = NULL;
426 struct extent_buffer *node = path->nodes[level];
427 struct btrfs_disk_key parent_key;
428 struct btrfs_disk_key node_key;
429 int parent_slot;
430 int slot;
431 struct btrfs_key cpukey;
432 u32 nritems = btrfs_header_nritems(node);
433
434 if (path->nodes[level + 1])
435 parent = path->nodes[level + 1];
436
437 slot = path->slots[level];
438 BUG_ON(nritems == 0);
439 if (parent) {
440 parent_slot = path->slots[level + 1];
441 btrfs_node_key(parent, &parent_key, parent_slot);
442 btrfs_node_key(node, &node_key, 0);
443 BUG_ON(memcmp(&parent_key, &node_key,
444 sizeof(struct btrfs_disk_key)));
445 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
446 btrfs_header_bytenr(node));
447 }
448 BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
449 if (slot != 0) {
450 btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
451 btrfs_node_key(node, &node_key, slot);
452 BUG_ON(comp_keys(&node_key, &cpukey) <= 0);
453 }
454 if (slot < nritems - 1) {
455 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
456 btrfs_node_key(node, &node_key, slot);
457 BUG_ON(comp_keys(&node_key, &cpukey) >= 0);
458 }
459 return 0;
460 }
461
462 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
463 int level)
464 {
465 struct extent_buffer *leaf = path->nodes[level];
466 struct extent_buffer *parent = NULL;
467 int parent_slot;
468 struct btrfs_key cpukey;
469 struct btrfs_disk_key parent_key;
470 struct btrfs_disk_key leaf_key;
471 int slot = path->slots[0];
472
473 u32 nritems = btrfs_header_nritems(leaf);
474
475 if (path->nodes[level + 1])
476 parent = path->nodes[level + 1];
477
478 if (nritems == 0)
479 return 0;
480
481 if (parent) {
482 parent_slot = path->slots[level + 1];
483 btrfs_node_key(parent, &parent_key, parent_slot);
484 btrfs_item_key(leaf, &leaf_key, 0);
485
486 BUG_ON(memcmp(&parent_key, &leaf_key,
487 sizeof(struct btrfs_disk_key)));
488 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
489 btrfs_header_bytenr(leaf));
490 }
491 #if 0
492 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
493 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
494 btrfs_item_key(leaf, &leaf_key, i);
495 if (comp_keys(&leaf_key, &cpukey) >= 0) {
496 btrfs_print_leaf(root, leaf);
497 printk("slot %d offset bad key\n", i);
498 BUG_ON(1);
499 }
500 if (btrfs_item_offset_nr(leaf, i) !=
501 btrfs_item_end_nr(leaf, i + 1)) {
502 btrfs_print_leaf(root, leaf);
503 printk("slot %d offset bad\n", i);
504 BUG_ON(1);
505 }
506 if (i == 0) {
507 if (btrfs_item_offset_nr(leaf, i) +
508 btrfs_item_size_nr(leaf, i) !=
509 BTRFS_LEAF_DATA_SIZE(root)) {
510 btrfs_print_leaf(root, leaf);
511 printk("slot %d first offset bad\n", i);
512 BUG_ON(1);
513 }
514 }
515 }
516 if (nritems > 0) {
517 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
518 btrfs_print_leaf(root, leaf);
519 printk("slot %d bad size \n", nritems - 1);
520 BUG_ON(1);
521 }
522 }
523 #endif
524 if (slot != 0 && slot < nritems - 1) {
525 btrfs_item_key(leaf, &leaf_key, slot);
526 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
527 if (comp_keys(&leaf_key, &cpukey) <= 0) {
528 btrfs_print_leaf(root, leaf);
529 printk("slot %d offset bad key\n", slot);
530 BUG_ON(1);
531 }
532 if (btrfs_item_offset_nr(leaf, slot - 1) !=
533 btrfs_item_end_nr(leaf, slot)) {
534 btrfs_print_leaf(root, leaf);
535 printk("slot %d offset bad\n", slot);
536 BUG_ON(1);
537 }
538 }
539 if (slot < nritems - 1) {
540 btrfs_item_key(leaf, &leaf_key, slot);
541 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
542 BUG_ON(comp_keys(&leaf_key, &cpukey) >= 0);
543 if (btrfs_item_offset_nr(leaf, slot) !=
544 btrfs_item_end_nr(leaf, slot + 1)) {
545 btrfs_print_leaf(root, leaf);
546 printk("slot %d offset bad\n", slot);
547 BUG_ON(1);
548 }
549 }
550 BUG_ON(btrfs_item_offset_nr(leaf, 0) +
551 btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
552 return 0;
553 }
554
555 static int noinline check_block(struct btrfs_root *root,
556 struct btrfs_path *path, int level)
557 {
558 return 0;
559 #if 0
560 struct extent_buffer *buf = path->nodes[level];
561
562 if (memcmp_extent_buffer(buf, root->fs_info->fsid,
563 (unsigned long)btrfs_header_fsid(buf),
564 BTRFS_FSID_SIZE)) {
565 printk("warning bad block %Lu\n", buf->start);
566 return 1;
567 }
568 #endif
569 if (level == 0)
570 return check_leaf(root, path, level);
571 return check_node(root, path, level);
572 }
573
574 /*
575 * search for key in the extent_buffer. The items start at offset p,
576 * and they are item_size apart. There are 'max' items in p.
577 *
578 * the slot in the array is returned via slot, and it points to
579 * the place where you would insert key if it is not found in
580 * the array.
581 *
582 * slot may point to max if the key is bigger than all of the keys
583 */
584 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
585 int item_size, struct btrfs_key *key,
586 int max, int *slot)
587 {
588 int low = 0;
589 int high = max;
590 int mid;
591 int ret;
592 struct btrfs_disk_key *tmp = NULL;
593 struct btrfs_disk_key unaligned;
594 unsigned long offset;
595 char *map_token = NULL;
596 char *kaddr = NULL;
597 unsigned long map_start = 0;
598 unsigned long map_len = 0;
599 int err;
600
601 while(low < high) {
602 mid = (low + high) / 2;
603 offset = p + mid * item_size;
604
605 if (!map_token || offset < map_start ||
606 (offset + sizeof(struct btrfs_disk_key)) >
607 map_start + map_len) {
608 if (map_token) {
609 unmap_extent_buffer(eb, map_token, KM_USER0);
610 map_token = NULL;
611 }
612 err = map_extent_buffer(eb, offset,
613 sizeof(struct btrfs_disk_key),
614 &map_token, &kaddr,
615 &map_start, &map_len, KM_USER0);
616
617 if (!err) {
618 tmp = (struct btrfs_disk_key *)(kaddr + offset -
619 map_start);
620 } else {
621 read_extent_buffer(eb, &unaligned,
622 offset, sizeof(unaligned));
623 tmp = &unaligned;
624 }
625
626 } else {
627 tmp = (struct btrfs_disk_key *)(kaddr + offset -
628 map_start);
629 }
630 ret = comp_keys(tmp, key);
631
632 if (ret < 0)
633 low = mid + 1;
634 else if (ret > 0)
635 high = mid;
636 else {
637 *slot = mid;
638 if (map_token)
639 unmap_extent_buffer(eb, map_token, KM_USER0);
640 return 0;
641 }
642 }
643 *slot = low;
644 if (map_token)
645 unmap_extent_buffer(eb, map_token, KM_USER0);
646 return 1;
647 }
648
649 /*
650 * simple bin_search frontend that does the right thing for
651 * leaves vs nodes
652 */
653 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
654 int level, int *slot)
655 {
656 if (level == 0) {
657 return generic_bin_search(eb,
658 offsetof(struct btrfs_leaf, items),
659 sizeof(struct btrfs_item),
660 key, btrfs_header_nritems(eb),
661 slot);
662 } else {
663 return generic_bin_search(eb,
664 offsetof(struct btrfs_node, ptrs),
665 sizeof(struct btrfs_key_ptr),
666 key, btrfs_header_nritems(eb),
667 slot);
668 }
669 return -1;
670 }
671
672 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
673 struct extent_buffer *parent, int slot)
674 {
675 if (slot < 0)
676 return NULL;
677 if (slot >= btrfs_header_nritems(parent))
678 return NULL;
679 return read_tree_block(root, btrfs_node_blockptr(parent, slot),
680 btrfs_level_size(root, btrfs_header_level(parent) - 1));
681 }
682
683 static int balance_level(struct btrfs_trans_handle *trans,
684 struct btrfs_root *root,
685 struct btrfs_path *path, int level)
686 {
687 struct extent_buffer *right = NULL;
688 struct extent_buffer *mid;
689 struct extent_buffer *left = NULL;
690 struct extent_buffer *parent = NULL;
691 int ret = 0;
692 int wret;
693 int pslot;
694 int orig_slot = path->slots[level];
695 int err_on_enospc = 0;
696 u64 orig_ptr;
697
698 if (level == 0)
699 return 0;
700
701 mid = path->nodes[level];
702 WARN_ON(btrfs_header_generation(mid) != trans->transid);
703
704 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
705
706 if (level < BTRFS_MAX_LEVEL - 1)
707 parent = path->nodes[level + 1];
708 pslot = path->slots[level + 1];
709
710 /*
711 * deal with the case where there is only one pointer in the root
712 * by promoting the node below to a root
713 */
714 if (!parent) {
715 struct extent_buffer *child;
716
717 if (btrfs_header_nritems(mid) != 1)
718 return 0;
719
720 /* promote the child to a root */
721 child = read_node_slot(root, mid, 0);
722 BUG_ON(!child);
723 ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
724 BUG_ON(ret);
725
726 root->node = child;
727 path->nodes[level] = NULL;
728 clean_tree_block(trans, root, mid);
729 wait_on_tree_block_writeback(root, mid);
730 /* once for the path */
731 free_extent_buffer(mid);
732 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
733 root->root_key.objectid,
734 btrfs_header_generation(mid), 0, 0, 1);
735 /* once for the root ptr */
736 free_extent_buffer(mid);
737 return ret;
738 }
739 if (btrfs_header_nritems(mid) >
740 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
741 return 0;
742
743 if (btrfs_header_nritems(mid) < 2)
744 err_on_enospc = 1;
745
746 left = read_node_slot(root, parent, pslot - 1);
747 if (left) {
748 wret = btrfs_cow_block(trans, root, left,
749 parent, pslot - 1, &left);
750 if (wret) {
751 ret = wret;
752 goto enospc;
753 }
754 }
755 right = read_node_slot(root, parent, pslot + 1);
756 if (right) {
757 wret = btrfs_cow_block(trans, root, right,
758 parent, pslot + 1, &right);
759 if (wret) {
760 ret = wret;
761 goto enospc;
762 }
763 }
764
765 /* first, try to make some room in the middle buffer */
766 if (left) {
767 orig_slot += btrfs_header_nritems(left);
768 wret = push_node_left(trans, root, left, mid);
769 if (wret < 0)
770 ret = wret;
771 if (btrfs_header_nritems(mid) < 2)
772 err_on_enospc = 1;
773 }
774
775 /*
776 * then try to empty the right most buffer into the middle
777 */
778 if (right) {
779 wret = push_node_left(trans, root, mid, right);
780 if (wret < 0 && wret != -ENOSPC)
781 ret = wret;
782 if (btrfs_header_nritems(right) == 0) {
783 u64 bytenr = right->start;
784 u64 generation = btrfs_header_generation(parent);
785 u32 blocksize = right->len;
786
787 clean_tree_block(trans, root, right);
788 wait_on_tree_block_writeback(root, right);
789 free_extent_buffer(right);
790 right = NULL;
791 wret = del_ptr(trans, root, path, level + 1, pslot +
792 1);
793 if (wret)
794 ret = wret;
795 wret = btrfs_free_extent(trans, root, bytenr,
796 blocksize,
797 btrfs_header_owner(parent),
798 generation, 0, 0, 1);
799 if (wret)
800 ret = wret;
801 } else {
802 struct btrfs_disk_key right_key;
803 btrfs_node_key(right, &right_key, 0);
804 btrfs_set_node_key(parent, &right_key, pslot + 1);
805 btrfs_mark_buffer_dirty(parent);
806 }
807 }
808 if (btrfs_header_nritems(mid) == 1) {
809 /*
810 * we're not allowed to leave a node with one item in the
811 * tree during a delete. A deletion from lower in the tree
812 * could try to delete the only pointer in this node.
813 * So, pull some keys from the left.
814 * There has to be a left pointer at this point because
815 * otherwise we would have pulled some pointers from the
816 * right
817 */
818 BUG_ON(!left);
819 wret = balance_node_right(trans, root, mid, left);
820 if (wret < 0) {
821 ret = wret;
822 goto enospc;
823 }
824 BUG_ON(wret == 1);
825 }
826 if (btrfs_header_nritems(mid) == 0) {
827 /* we've managed to empty the middle node, drop it */
828 u64 root_gen = btrfs_header_generation(parent);
829 u64 bytenr = mid->start;
830 u32 blocksize = mid->len;
831 clean_tree_block(trans, root, mid);
832 wait_on_tree_block_writeback(root, mid);
833 free_extent_buffer(mid);
834 mid = NULL;
835 wret = del_ptr(trans, root, path, level + 1, pslot);
836 if (wret)
837 ret = wret;
838 wret = btrfs_free_extent(trans, root, bytenr, blocksize,
839 btrfs_header_owner(parent),
840 root_gen, 0, 0, 1);
841 if (wret)
842 ret = wret;
843 } else {
844 /* update the parent key to reflect our changes */
845 struct btrfs_disk_key mid_key;
846 btrfs_node_key(mid, &mid_key, 0);
847 btrfs_set_node_key(parent, &mid_key, pslot);
848 btrfs_mark_buffer_dirty(parent);
849 }
850
851 /* update the path */
852 if (left) {
853 if (btrfs_header_nritems(left) > orig_slot) {
854 extent_buffer_get(left);
855 path->nodes[level] = left;
856 path->slots[level + 1] -= 1;
857 path->slots[level] = orig_slot;
858 if (mid)
859 free_extent_buffer(mid);
860 } else {
861 orig_slot -= btrfs_header_nritems(left);
862 path->slots[level] = orig_slot;
863 }
864 }
865 /* double check we haven't messed things up */
866 check_block(root, path, level);
867 if (orig_ptr !=
868 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
869 BUG();
870 enospc:
871 if (right)
872 free_extent_buffer(right);
873 if (left)
874 free_extent_buffer(left);
875 return ret;
876 }
877
878 /* returns zero if the push worked, non-zero otherwise */
879 static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
880 struct btrfs_root *root,
881 struct btrfs_path *path, int level)
882 {
883 struct extent_buffer *right = NULL;
884 struct extent_buffer *mid;
885 struct extent_buffer *left = NULL;
886 struct extent_buffer *parent = NULL;
887 int ret = 0;
888 int wret;
889 int pslot;
890 int orig_slot = path->slots[level];
891 u64 orig_ptr;
892
893 if (level == 0)
894 return 1;
895
896 mid = path->nodes[level];
897 WARN_ON(btrfs_header_generation(mid) != trans->transid);
898 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
899
900 if (level < BTRFS_MAX_LEVEL - 1)
901 parent = path->nodes[level + 1];
902 pslot = path->slots[level + 1];
903
904 if (!parent)
905 return 1;
906
907 left = read_node_slot(root, parent, pslot - 1);
908
909 /* first, try to make some room in the middle buffer */
910 if (left) {
911 u32 left_nr;
912 left_nr = btrfs_header_nritems(left);
913 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
914 wret = 1;
915 } else {
916 ret = btrfs_cow_block(trans, root, left, parent,
917 pslot - 1, &left);
918 if (ret)
919 wret = 1;
920 else {
921 wret = push_node_left(trans, root,
922 left, mid);
923 }
924 }
925 if (wret < 0)
926 ret = wret;
927 if (wret == 0) {
928 struct btrfs_disk_key disk_key;
929 orig_slot += left_nr;
930 btrfs_node_key(mid, &disk_key, 0);
931 btrfs_set_node_key(parent, &disk_key, pslot);
932 btrfs_mark_buffer_dirty(parent);
933 if (btrfs_header_nritems(left) > orig_slot) {
934 path->nodes[level] = left;
935 path->slots[level + 1] -= 1;
936 path->slots[level] = orig_slot;
937 free_extent_buffer(mid);
938 } else {
939 orig_slot -=
940 btrfs_header_nritems(left);
941 path->slots[level] = orig_slot;
942 free_extent_buffer(left);
943 }
944 return 0;
945 }
946 free_extent_buffer(left);
947 }
948 right= read_node_slot(root, parent, pslot + 1);
949
950 /*
951 * then try to empty the right most buffer into the middle
952 */
953 if (right) {
954 u32 right_nr;
955 right_nr = btrfs_header_nritems(right);
956 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
957 wret = 1;
958 } else {
959 ret = btrfs_cow_block(trans, root, right,
960 parent, pslot + 1,
961 &right);
962 if (ret)
963 wret = 1;
964 else {
965 wret = balance_node_right(trans, root,
966 right, mid);
967 }
968 }
969 if (wret < 0)
970 ret = wret;
971 if (wret == 0) {
972 struct btrfs_disk_key disk_key;
973
974 btrfs_node_key(right, &disk_key, 0);
975 btrfs_set_node_key(parent, &disk_key, pslot + 1);
976 btrfs_mark_buffer_dirty(parent);
977
978 if (btrfs_header_nritems(mid) <= orig_slot) {
979 path->nodes[level] = right;
980 path->slots[level + 1] += 1;
981 path->slots[level] = orig_slot -
982 btrfs_header_nritems(mid);
983 free_extent_buffer(mid);
984 } else {
985 free_extent_buffer(right);
986 }
987 return 0;
988 }
989 free_extent_buffer(right);
990 }
991 return 1;
992 }
993
994 /*
995 * readahead one full node of leaves
996 */
997 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
998 int level, int slot, u64 objectid)
999 {
1000 struct extent_buffer *node;
1001 struct btrfs_disk_key disk_key;
1002 u32 nritems;
1003 u64 search;
1004 u64 lowest_read;
1005 u64 highest_read;
1006 u64 nread = 0;
1007 int direction = path->reada;
1008 struct extent_buffer *eb;
1009 u32 nr;
1010 u32 blocksize;
1011 u32 nscan = 0;
1012
1013 if (level != 1)
1014 return;
1015
1016 if (!path->nodes[level])
1017 return;
1018
1019 node = path->nodes[level];
1020 search = btrfs_node_blockptr(node, slot);
1021 blocksize = btrfs_level_size(root, level - 1);
1022 eb = btrfs_find_tree_block(root, search, blocksize);
1023 if (eb) {
1024 free_extent_buffer(eb);
1025 return;
1026 }
1027
1028 highest_read = search;
1029 lowest_read = search;
1030
1031 nritems = btrfs_header_nritems(node);
1032 nr = slot;
1033 while(1) {
1034 if (direction < 0) {
1035 if (nr == 0)
1036 break;
1037 nr--;
1038 } else if (direction > 0) {
1039 nr++;
1040 if (nr >= nritems)
1041 break;
1042 }
1043 if (path->reada < 0 && objectid) {
1044 btrfs_node_key(node, &disk_key, nr);
1045 if (btrfs_disk_key_objectid(&disk_key) != objectid)
1046 break;
1047 }
1048 search = btrfs_node_blockptr(node, nr);
1049 if ((search >= lowest_read && search <= highest_read) ||
1050 (search < lowest_read && lowest_read - search <= 32768) ||
1051 (search > highest_read && search - highest_read <= 32768)) {
1052 readahead_tree_block(root, search, blocksize);
1053 nread += blocksize;
1054 }
1055 nscan++;
1056 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
1057 break;
1058 if(nread > (1024 * 1024) || nscan > 128)
1059 break;
1060
1061 if (search < lowest_read)
1062 lowest_read = search;
1063 if (search > highest_read)
1064 highest_read = search;
1065 }
1066 }
1067 /*
1068 * look for key in the tree. path is filled in with nodes along the way
1069 * if key is found, we return zero and you can find the item in the leaf
1070 * level of the path (level 0)
1071 *
1072 * If the key isn't found, the path points to the slot where it should
1073 * be inserted, and 1 is returned. If there are other errors during the
1074 * search a negative error number is returned.
1075 *
1076 * if ins_len > 0, nodes and leaves will be split as we walk down the
1077 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
1078 * possible)
1079 */
1080 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
1081 *root, struct btrfs_key *key, struct btrfs_path *p, int
1082 ins_len, int cow)
1083 {
1084 struct extent_buffer *b;
1085 u64 bytenr;
1086 u64 ptr_gen;
1087 int slot;
1088 int ret;
1089 int level;
1090 int should_reada = p->reada;
1091 u8 lowest_level = 0;
1092
1093 lowest_level = p->lowest_level;
1094 WARN_ON(lowest_level && ins_len);
1095 WARN_ON(p->nodes[0] != NULL);
1096 WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
1097 again:
1098 b = root->node;
1099 extent_buffer_get(b);
1100 while (b) {
1101 level = btrfs_header_level(b);
1102 if (cow) {
1103 int wret;
1104 wret = btrfs_cow_block(trans, root, b,
1105 p->nodes[level + 1],
1106 p->slots[level + 1],
1107 &b);
1108 if (wret) {
1109 free_extent_buffer(b);
1110 return wret;
1111 }
1112 }
1113 BUG_ON(!cow && ins_len);
1114 if (level != btrfs_header_level(b))
1115 WARN_ON(1);
1116 level = btrfs_header_level(b);
1117 p->nodes[level] = b;
1118 ret = check_block(root, p, level);
1119 if (ret)
1120 return -1;
1121 ret = bin_search(b, key, level, &slot);
1122 if (level != 0) {
1123 if (ret && slot > 0)
1124 slot -= 1;
1125 p->slots[level] = slot;
1126 if (ins_len > 0 && btrfs_header_nritems(b) >=
1127 BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1128 int sret = split_node(trans, root, p, level);
1129 BUG_ON(sret > 0);
1130 if (sret)
1131 return sret;
1132 b = p->nodes[level];
1133 slot = p->slots[level];
1134 } else if (ins_len < 0) {
1135 int sret = balance_level(trans, root, p,
1136 level);
1137 if (sret)
1138 return sret;
1139 b = p->nodes[level];
1140 if (!b) {
1141 btrfs_release_path(NULL, p);
1142 goto again;
1143 }
1144 slot = p->slots[level];
1145 BUG_ON(btrfs_header_nritems(b) == 1);
1146 }
1147 /* this is only true while dropping a snapshot */
1148 if (level == lowest_level)
1149 break;
1150 bytenr = btrfs_node_blockptr(b, slot);
1151 ptr_gen = btrfs_node_ptr_generation(b, slot);
1152 if (should_reada)
1153 reada_for_search(root, p, level, slot,
1154 key->objectid);
1155 b = read_tree_block(root, bytenr,
1156 btrfs_level_size(root, level - 1));
1157 if (ptr_gen != btrfs_header_generation(b)) {
1158 printk("block %llu bad gen wanted %llu "
1159 "found %llu\n",
1160 (unsigned long long)b->start,
1161 (unsigned long long)ptr_gen,
1162 (unsigned long long)btrfs_header_generation(b));
1163 }
1164 } else {
1165 p->slots[level] = slot;
1166 if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1167 sizeof(struct btrfs_item) + ins_len) {
1168 int sret = split_leaf(trans, root, key,
1169 p, ins_len, ret == 0);
1170 BUG_ON(sret > 0);
1171 if (sret)
1172 return sret;
1173 }
1174 return ret;
1175 }
1176 }
1177 return 1;
1178 }
1179
1180 /*
1181 * adjust the pointers going up the tree, starting at level
1182 * making sure the right key of each node is points to 'key'.
1183 * This is used after shifting pointers to the left, so it stops
1184 * fixing up pointers when a given leaf/node is not in slot 0 of the
1185 * higher levels
1186 *
1187 * If this fails to write a tree block, it returns -1, but continues
1188 * fixing up the blocks in ram so the tree is consistent.
1189 */
1190 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1191 struct btrfs_root *root, struct btrfs_path *path,
1192 struct btrfs_disk_key *key, int level)
1193 {
1194 int i;
1195 int ret = 0;
1196 struct extent_buffer *t;
1197
1198 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1199 int tslot = path->slots[i];
1200 if (!path->nodes[i])
1201 break;
1202 t = path->nodes[i];
1203 btrfs_set_node_key(t, key, tslot);
1204 btrfs_mark_buffer_dirty(path->nodes[i]);
1205 if (tslot != 0)
1206 break;
1207 }
1208 return ret;
1209 }
1210
1211 /*
1212 * try to push data from one node into the next node left in the
1213 * tree.
1214 *
1215 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1216 * error, and > 0 if there was no room in the left hand block.
1217 */
1218 static int push_node_left(struct btrfs_trans_handle *trans,
1219 struct btrfs_root *root, struct extent_buffer *dst,
1220 struct extent_buffer *src)
1221 {
1222 int push_items = 0;
1223 int src_nritems;
1224 int dst_nritems;
1225 int ret = 0;
1226
1227 src_nritems = btrfs_header_nritems(src);
1228 dst_nritems = btrfs_header_nritems(dst);
1229 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1230 WARN_ON(btrfs_header_generation(src) != trans->transid);
1231 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1232
1233 if (push_items <= 0) {
1234 return 1;
1235 }
1236
1237 if (src_nritems < push_items)
1238 push_items = src_nritems;
1239
1240 copy_extent_buffer(dst, src,
1241 btrfs_node_key_ptr_offset(dst_nritems),
1242 btrfs_node_key_ptr_offset(0),
1243 push_items * sizeof(struct btrfs_key_ptr));
1244
1245 if (push_items < src_nritems) {
1246 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1247 btrfs_node_key_ptr_offset(push_items),
1248 (src_nritems - push_items) *
1249 sizeof(struct btrfs_key_ptr));
1250 }
1251 btrfs_set_header_nritems(src, src_nritems - push_items);
1252 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1253 btrfs_mark_buffer_dirty(src);
1254 btrfs_mark_buffer_dirty(dst);
1255 return ret;
1256 }
1257
1258 /*
1259 * try to push data from one node into the next node right in the
1260 * tree.
1261 *
1262 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1263 * error, and > 0 if there was no room in the right hand block.
1264 *
1265 * this will only push up to 1/2 the contents of the left node over
1266 */
1267 static int balance_node_right(struct btrfs_trans_handle *trans,
1268 struct btrfs_root *root,
1269 struct extent_buffer *dst,
1270 struct extent_buffer *src)
1271 {
1272 int push_items = 0;
1273 int max_push;
1274 int src_nritems;
1275 int dst_nritems;
1276 int ret = 0;
1277
1278 WARN_ON(btrfs_header_generation(src) != trans->transid);
1279 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1280
1281 src_nritems = btrfs_header_nritems(src);
1282 dst_nritems = btrfs_header_nritems(dst);
1283 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1284 if (push_items <= 0)
1285 return 1;
1286
1287 max_push = src_nritems / 2 + 1;
1288 /* don't try to empty the node */
1289 if (max_push >= src_nritems)
1290 return 1;
1291
1292 if (max_push < push_items)
1293 push_items = max_push;
1294
1295 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1296 btrfs_node_key_ptr_offset(0),
1297 (dst_nritems) *
1298 sizeof(struct btrfs_key_ptr));
1299
1300 copy_extent_buffer(dst, src,
1301 btrfs_node_key_ptr_offset(0),
1302 btrfs_node_key_ptr_offset(src_nritems - push_items),
1303 push_items * sizeof(struct btrfs_key_ptr));
1304
1305 btrfs_set_header_nritems(src, src_nritems - push_items);
1306 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1307
1308 btrfs_mark_buffer_dirty(src);
1309 btrfs_mark_buffer_dirty(dst);
1310 return ret;
1311 }
1312
1313 /*
1314 * helper function to insert a new root level in the tree.
1315 * A new node is allocated, and a single item is inserted to
1316 * point to the existing root
1317 *
1318 * returns zero on success or < 0 on failure.
1319 */
1320 static int noinline insert_new_root(struct btrfs_trans_handle *trans,
1321 struct btrfs_root *root,
1322 struct btrfs_path *path, int level)
1323 {
1324 u64 root_gen;
1325 u64 lower_gen;
1326 struct extent_buffer *lower;
1327 struct extent_buffer *c;
1328 struct btrfs_disk_key lower_key;
1329
1330 BUG_ON(path->nodes[level]);
1331 BUG_ON(path->nodes[level-1] != root->node);
1332
1333 if (root->ref_cows)
1334 root_gen = trans->transid;
1335 else
1336 root_gen = 0;
1337
1338 lower = path->nodes[level-1];
1339 if (level == 1)
1340 btrfs_item_key(lower, &lower_key, 0);
1341 else
1342 btrfs_node_key(lower, &lower_key, 0);
1343
1344 c = __btrfs_alloc_free_block(trans, root, root->nodesize,
1345 root->root_key.objectid,
1346 root_gen, lower_key.objectid, level,
1347 root->node->start, 0);
1348 if (IS_ERR(c))
1349 return PTR_ERR(c);
1350 memset_extent_buffer(c, 0, 0, root->nodesize);
1351 btrfs_set_header_nritems(c, 1);
1352 btrfs_set_header_level(c, level);
1353 btrfs_set_header_bytenr(c, c->start);
1354 btrfs_set_header_generation(c, trans->transid);
1355 btrfs_set_header_owner(c, root->root_key.objectid);
1356
1357 write_extent_buffer(c, root->fs_info->fsid,
1358 (unsigned long)btrfs_header_fsid(c),
1359 BTRFS_FSID_SIZE);
1360 btrfs_set_node_key(c, &lower_key, 0);
1361 btrfs_set_node_blockptr(c, 0, lower->start);
1362 lower_gen = btrfs_header_generation(lower);
1363 WARN_ON(lower_gen == 0);
1364
1365 btrfs_set_node_ptr_generation(c, 0, lower_gen);
1366
1367 btrfs_mark_buffer_dirty(c);
1368
1369 /* the super has an extra ref to root->node */
1370 free_extent_buffer(root->node);
1371 root->node = c;
1372 extent_buffer_get(c);
1373 path->nodes[level] = c;
1374 path->slots[level] = 0;
1375
1376 if (root->ref_cows && lower_gen != trans->transid) {
1377 struct btrfs_path *back_path = btrfs_alloc_path();
1378 int ret;
1379 ret = btrfs_insert_extent_backref(trans,
1380 root->fs_info->extent_root,
1381 path, lower->start,
1382 root->root_key.objectid,
1383 trans->transid, 0, 0);
1384 BUG_ON(ret);
1385 btrfs_free_path(back_path);
1386 }
1387 return 0;
1388 }
1389
1390 /*
1391 * worker function to insert a single pointer in a node.
1392 * the node should have enough room for the pointer already
1393 *
1394 * slot and level indicate where you want the key to go, and
1395 * blocknr is the block the key points to.
1396 *
1397 * returns zero on success and < 0 on any error
1398 */
1399 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1400 *root, struct btrfs_path *path, struct btrfs_disk_key
1401 *key, u64 bytenr, int slot, int level)
1402 {
1403 struct extent_buffer *lower;
1404 int nritems;
1405
1406 BUG_ON(!path->nodes[level]);
1407 lower = path->nodes[level];
1408 nritems = btrfs_header_nritems(lower);
1409 if (slot > nritems)
1410 BUG();
1411 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1412 BUG();
1413 if (slot != nritems) {
1414 memmove_extent_buffer(lower,
1415 btrfs_node_key_ptr_offset(slot + 1),
1416 btrfs_node_key_ptr_offset(slot),
1417 (nritems - slot) * sizeof(struct btrfs_key_ptr));
1418 }
1419 btrfs_set_node_key(lower, key, slot);
1420 btrfs_set_node_blockptr(lower, slot, bytenr);
1421 WARN_ON(trans->transid == 0);
1422 btrfs_set_node_ptr_generation(lower, slot, trans->transid);
1423 btrfs_set_header_nritems(lower, nritems + 1);
1424 btrfs_mark_buffer_dirty(lower);
1425 return 0;
1426 }
1427
1428 /*
1429 * split the node at the specified level in path in two.
1430 * The path is corrected to point to the appropriate node after the split
1431 *
1432 * Before splitting this tries to make some room in the node by pushing
1433 * left and right, if either one works, it returns right away.
1434 *
1435 * returns 0 on success and < 0 on failure
1436 */
1437 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1438 *root, struct btrfs_path *path, int level)
1439 {
1440 u64 root_gen;
1441 struct extent_buffer *c;
1442 struct extent_buffer *split;
1443 struct btrfs_disk_key disk_key;
1444 int mid;
1445 int ret;
1446 int wret;
1447 u32 c_nritems;
1448
1449 c = path->nodes[level];
1450 WARN_ON(btrfs_header_generation(c) != trans->transid);
1451 if (c == root->node) {
1452 /* trying to split the root, lets make a new one */
1453 ret = insert_new_root(trans, root, path, level + 1);
1454 if (ret)
1455 return ret;
1456 } else {
1457 ret = push_nodes_for_insert(trans, root, path, level);
1458 c = path->nodes[level];
1459 if (!ret && btrfs_header_nritems(c) <
1460 BTRFS_NODEPTRS_PER_BLOCK(root) - 1)
1461 return 0;
1462 if (ret < 0)
1463 return ret;
1464 }
1465
1466 c_nritems = btrfs_header_nritems(c);
1467 if (root->ref_cows)
1468 root_gen = trans->transid;
1469 else
1470 root_gen = 0;
1471
1472 btrfs_node_key(c, &disk_key, 0);
1473 split = __btrfs_alloc_free_block(trans, root, root->nodesize,
1474 root->root_key.objectid,
1475 root_gen,
1476 btrfs_disk_key_objectid(&disk_key),
1477 level, c->start, 0);
1478 if (IS_ERR(split))
1479 return PTR_ERR(split);
1480
1481 btrfs_set_header_flags(split, btrfs_header_flags(c));
1482 btrfs_set_header_level(split, btrfs_header_level(c));
1483 btrfs_set_header_bytenr(split, split->start);
1484 btrfs_set_header_generation(split, trans->transid);
1485 btrfs_set_header_owner(split, root->root_key.objectid);
1486 write_extent_buffer(split, root->fs_info->fsid,
1487 (unsigned long)btrfs_header_fsid(split),
1488 BTRFS_FSID_SIZE);
1489
1490 mid = (c_nritems + 1) / 2;
1491
1492 copy_extent_buffer(split, c,
1493 btrfs_node_key_ptr_offset(0),
1494 btrfs_node_key_ptr_offset(mid),
1495 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1496 btrfs_set_header_nritems(split, c_nritems - mid);
1497 btrfs_set_header_nritems(c, mid);
1498 ret = 0;
1499
1500 btrfs_mark_buffer_dirty(c);
1501 btrfs_mark_buffer_dirty(split);
1502
1503 btrfs_node_key(split, &disk_key, 0);
1504 wret = insert_ptr(trans, root, path, &disk_key, split->start,
1505 path->slots[level + 1] + 1,
1506 level + 1);
1507 if (wret)
1508 ret = wret;
1509
1510 if (path->slots[level] >= mid) {
1511 path->slots[level] -= mid;
1512 free_extent_buffer(c);
1513 path->nodes[level] = split;
1514 path->slots[level + 1] += 1;
1515 } else {
1516 free_extent_buffer(split);
1517 }
1518 return ret;
1519 }
1520
1521 /*
1522 * how many bytes are required to store the items in a leaf. start
1523 * and nr indicate which items in the leaf to check. This totals up the
1524 * space used both by the item structs and the item data
1525 */
1526 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1527 {
1528 int data_len;
1529 int nritems = btrfs_header_nritems(l);
1530 int end = min(nritems, start + nr) - 1;
1531
1532 if (!nr)
1533 return 0;
1534 data_len = btrfs_item_end_nr(l, start);
1535 data_len = data_len - btrfs_item_offset_nr(l, end);
1536 data_len += sizeof(struct btrfs_item) * nr;
1537 WARN_ON(data_len < 0);
1538 return data_len;
1539 }
1540
1541 /*
1542 * The space between the end of the leaf items and
1543 * the start of the leaf data. IOW, how much room
1544 * the leaf has left for both items and data
1545 */
1546 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1547 {
1548 int nritems = btrfs_header_nritems(leaf);
1549 int ret;
1550 ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1551 if (ret < 0) {
1552 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1553 ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
1554 leaf_space_used(leaf, 0, nritems), nritems);
1555 }
1556 return ret;
1557 }
1558
1559 /*
1560 * push some data in the path leaf to the right, trying to free up at
1561 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1562 *
1563 * returns 1 if the push failed because the other node didn't have enough
1564 * room, 0 if everything worked out and < 0 if there were major errors.
1565 */
1566 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1567 *root, struct btrfs_path *path, int data_size,
1568 int empty)
1569 {
1570 struct extent_buffer *left = path->nodes[0];
1571 struct extent_buffer *right;
1572 struct extent_buffer *upper;
1573 struct btrfs_disk_key disk_key;
1574 int slot;
1575 u32 i;
1576 int free_space;
1577 int push_space = 0;
1578 int push_items = 0;
1579 struct btrfs_item *item;
1580 u32 left_nritems;
1581 u32 nr;
1582 u32 right_nritems;
1583 u32 data_end;
1584 u32 this_item_size;
1585 int ret;
1586
1587 slot = path->slots[1];
1588 if (!path->nodes[1]) {
1589 return 1;
1590 }
1591 upper = path->nodes[1];
1592 if (slot >= btrfs_header_nritems(upper) - 1)
1593 return 1;
1594
1595 right = read_tree_block(root, btrfs_node_blockptr(upper, slot + 1),
1596 root->leafsize);
1597 free_space = btrfs_leaf_free_space(root, right);
1598 if (free_space < data_size + sizeof(struct btrfs_item)) {
1599 free_extent_buffer(right);
1600 return 1;
1601 }
1602
1603 /* cow and double check */
1604 ret = btrfs_cow_block(trans, root, right, upper,
1605 slot + 1, &right);
1606 if (ret) {
1607 free_extent_buffer(right);
1608 return 1;
1609 }
1610 free_space = btrfs_leaf_free_space(root, right);
1611 if (free_space < data_size + sizeof(struct btrfs_item)) {
1612 free_extent_buffer(right);
1613 return 1;
1614 }
1615
1616 left_nritems = btrfs_header_nritems(left);
1617 if (left_nritems == 0) {
1618 free_extent_buffer(right);
1619 return 1;
1620 }
1621
1622 if (empty)
1623 nr = 0;
1624 else
1625 nr = 1;
1626
1627 i = left_nritems - 1;
1628 while (i >= nr) {
1629 item = btrfs_item_nr(left, i);
1630
1631 if (path->slots[0] == i)
1632 push_space += data_size + sizeof(*item);
1633
1634 if (!left->map_token) {
1635 map_extent_buffer(left, (unsigned long)item,
1636 sizeof(struct btrfs_item),
1637 &left->map_token, &left->kaddr,
1638 &left->map_start, &left->map_len,
1639 KM_USER1);
1640 }
1641
1642 this_item_size = btrfs_item_size(left, item);
1643 if (this_item_size + sizeof(*item) + push_space > free_space)
1644 break;
1645 push_items++;
1646 push_space += this_item_size + sizeof(*item);
1647 if (i == 0)
1648 break;
1649 i--;
1650 }
1651 if (left->map_token) {
1652 unmap_extent_buffer(left, left->map_token, KM_USER1);
1653 left->map_token = NULL;
1654 }
1655
1656 if (push_items == 0) {
1657 free_extent_buffer(right);
1658 return 1;
1659 }
1660
1661 if (!empty && push_items == left_nritems)
1662 WARN_ON(1);
1663
1664 /* push left to right */
1665 right_nritems = btrfs_header_nritems(right);
1666
1667 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1668 push_space -= leaf_data_end(root, left);
1669
1670 /* make room in the right data area */
1671 data_end = leaf_data_end(root, right);
1672 memmove_extent_buffer(right,
1673 btrfs_leaf_data(right) + data_end - push_space,
1674 btrfs_leaf_data(right) + data_end,
1675 BTRFS_LEAF_DATA_SIZE(root) - data_end);
1676
1677 /* copy from the left data area */
1678 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1679 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1680 btrfs_leaf_data(left) + leaf_data_end(root, left),
1681 push_space);
1682
1683 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1684 btrfs_item_nr_offset(0),
1685 right_nritems * sizeof(struct btrfs_item));
1686
1687 /* copy the items from left to right */
1688 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1689 btrfs_item_nr_offset(left_nritems - push_items),
1690 push_items * sizeof(struct btrfs_item));
1691
1692 /* update the item pointers */
1693 right_nritems += push_items;
1694 btrfs_set_header_nritems(right, right_nritems);
1695 push_space = BTRFS_LEAF_DATA_SIZE(root);
1696 for (i = 0; i < right_nritems; i++) {
1697 item = btrfs_item_nr(right, i);
1698 if (!right->map_token) {
1699 map_extent_buffer(right, (unsigned long)item,
1700 sizeof(struct btrfs_item),
1701 &right->map_token, &right->kaddr,
1702 &right->map_start, &right->map_len,
1703 KM_USER1);
1704 }
1705 push_space -= btrfs_item_size(right, item);
1706 btrfs_set_item_offset(right, item, push_space);
1707 }
1708
1709 if (right->map_token) {
1710 unmap_extent_buffer(right, right->map_token, KM_USER1);
1711 right->map_token = NULL;
1712 }
1713 left_nritems -= push_items;
1714 btrfs_set_header_nritems(left, left_nritems);
1715
1716 if (left_nritems)
1717 btrfs_mark_buffer_dirty(left);
1718 btrfs_mark_buffer_dirty(right);
1719
1720 btrfs_item_key(right, &disk_key, 0);
1721 btrfs_set_node_key(upper, &disk_key, slot + 1);
1722 btrfs_mark_buffer_dirty(upper);
1723
1724 /* then fixup the leaf pointer in the path */
1725 if (path->slots[0] >= left_nritems) {
1726 path->slots[0] -= left_nritems;
1727 free_extent_buffer(path->nodes[0]);
1728 path->nodes[0] = right;
1729 path->slots[1] += 1;
1730 } else {
1731 free_extent_buffer(right);
1732 }
1733 return 0;
1734 }
1735 /*
1736 * push some data in the path leaf to the left, trying to free up at
1737 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1738 */
1739 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1740 *root, struct btrfs_path *path, int data_size,
1741 int empty)
1742 {
1743 struct btrfs_disk_key disk_key;
1744 struct extent_buffer *right = path->nodes[0];
1745 struct extent_buffer *left;
1746 int slot;
1747 int i;
1748 int free_space;
1749 int push_space = 0;
1750 int push_items = 0;
1751 struct btrfs_item *item;
1752 u32 old_left_nritems;
1753 u32 right_nritems;
1754 u32 nr;
1755 int ret = 0;
1756 int wret;
1757 u32 this_item_size;
1758 u32 old_left_item_size;
1759
1760 slot = path->slots[1];
1761 if (slot == 0)
1762 return 1;
1763 if (!path->nodes[1])
1764 return 1;
1765
1766 right_nritems = btrfs_header_nritems(right);
1767 if (right_nritems == 0) {
1768 return 1;
1769 }
1770
1771 left = read_tree_block(root, btrfs_node_blockptr(path->nodes[1],
1772 slot - 1), root->leafsize);
1773 free_space = btrfs_leaf_free_space(root, left);
1774 if (free_space < data_size + sizeof(struct btrfs_item)) {
1775 free_extent_buffer(left);
1776 return 1;
1777 }
1778
1779 /* cow and double check */
1780 ret = btrfs_cow_block(trans, root, left,
1781 path->nodes[1], slot - 1, &left);
1782 if (ret) {
1783 /* we hit -ENOSPC, but it isn't fatal here */
1784 free_extent_buffer(left);
1785 return 1;
1786 }
1787
1788 free_space = btrfs_leaf_free_space(root, left);
1789 if (free_space < data_size + sizeof(struct btrfs_item)) {
1790 free_extent_buffer(left);
1791 return 1;
1792 }
1793
1794 if (empty)
1795 nr = right_nritems;
1796 else
1797 nr = right_nritems - 1;
1798
1799 for (i = 0; i < nr; i++) {
1800 item = btrfs_item_nr(right, i);
1801 if (!right->map_token) {
1802 map_extent_buffer(right, (unsigned long)item,
1803 sizeof(struct btrfs_item),
1804 &right->map_token, &right->kaddr,
1805 &right->map_start, &right->map_len,
1806 KM_USER1);
1807 }
1808
1809 if (path->slots[0] == i)
1810 push_space += data_size + sizeof(*item);
1811
1812 this_item_size = btrfs_item_size(right, item);
1813 if (this_item_size + sizeof(*item) + push_space > free_space)
1814 break;
1815
1816 push_items++;
1817 push_space += this_item_size + sizeof(*item);
1818 }
1819
1820 if (right->map_token) {
1821 unmap_extent_buffer(right, right->map_token, KM_USER1);
1822 right->map_token = NULL;
1823 }
1824
1825 if (push_items == 0) {
1826 free_extent_buffer(left);
1827 return 1;
1828 }
1829 if (!empty && push_items == btrfs_header_nritems(right))
1830 WARN_ON(1);
1831
1832 /* push data from right to left */
1833 copy_extent_buffer(left, right,
1834 btrfs_item_nr_offset(btrfs_header_nritems(left)),
1835 btrfs_item_nr_offset(0),
1836 push_items * sizeof(struct btrfs_item));
1837
1838 push_space = BTRFS_LEAF_DATA_SIZE(root) -
1839 btrfs_item_offset_nr(right, push_items -1);
1840
1841 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
1842 leaf_data_end(root, left) - push_space,
1843 btrfs_leaf_data(right) +
1844 btrfs_item_offset_nr(right, push_items - 1),
1845 push_space);
1846 old_left_nritems = btrfs_header_nritems(left);
1847 BUG_ON(old_left_nritems < 0);
1848
1849 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
1850 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1851 u32 ioff;
1852
1853 item = btrfs_item_nr(left, i);
1854 if (!left->map_token) {
1855 map_extent_buffer(left, (unsigned long)item,
1856 sizeof(struct btrfs_item),
1857 &left->map_token, &left->kaddr,
1858 &left->map_start, &left->map_len,
1859 KM_USER1);
1860 }
1861
1862 ioff = btrfs_item_offset(left, item);
1863 btrfs_set_item_offset(left, item,
1864 ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
1865 }
1866 btrfs_set_header_nritems(left, old_left_nritems + push_items);
1867 if (left->map_token) {
1868 unmap_extent_buffer(left, left->map_token, KM_USER1);
1869 left->map_token = NULL;
1870 }
1871
1872 /* fixup right node */
1873 if (push_items > right_nritems) {
1874 printk("push items %d nr %u\n", push_items, right_nritems);
1875 WARN_ON(1);
1876 }
1877
1878 if (push_items < right_nritems) {
1879 push_space = btrfs_item_offset_nr(right, push_items - 1) -
1880 leaf_data_end(root, right);
1881 memmove_extent_buffer(right, btrfs_leaf_data(right) +
1882 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1883 btrfs_leaf_data(right) +
1884 leaf_data_end(root, right), push_space);
1885
1886 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
1887 btrfs_item_nr_offset(push_items),
1888 (btrfs_header_nritems(right) - push_items) *
1889 sizeof(struct btrfs_item));
1890 }
1891 right_nritems -= push_items;
1892 btrfs_set_header_nritems(right, right_nritems);
1893 push_space = BTRFS_LEAF_DATA_SIZE(root);
1894 for (i = 0; i < right_nritems; i++) {
1895 item = btrfs_item_nr(right, i);
1896
1897 if (!right->map_token) {
1898 map_extent_buffer(right, (unsigned long)item,
1899 sizeof(struct btrfs_item),
1900 &right->map_token, &right->kaddr,
1901 &right->map_start, &right->map_len,
1902 KM_USER1);
1903 }
1904
1905 push_space = push_space - btrfs_item_size(right, item);
1906 btrfs_set_item_offset(right, item, push_space);
1907 }
1908 if (right->map_token) {
1909 unmap_extent_buffer(right, right->map_token, KM_USER1);
1910 right->map_token = NULL;
1911 }
1912
1913 btrfs_mark_buffer_dirty(left);
1914 if (right_nritems)
1915 btrfs_mark_buffer_dirty(right);
1916
1917 btrfs_item_key(right, &disk_key, 0);
1918 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1919 if (wret)
1920 ret = wret;
1921
1922 /* then fixup the leaf pointer in the path */
1923 if (path->slots[0] < push_items) {
1924 path->slots[0] += old_left_nritems;
1925 free_extent_buffer(path->nodes[0]);
1926 path->nodes[0] = left;
1927 path->slots[1] -= 1;
1928 } else {
1929 free_extent_buffer(left);
1930 path->slots[0] -= push_items;
1931 }
1932 BUG_ON(path->slots[0] < 0);
1933 return ret;
1934 }
1935
1936 /*
1937 * split the path's leaf in two, making sure there is at least data_size
1938 * available for the resulting leaf level of the path.
1939 *
1940 * returns 0 if all went well and < 0 on failure.
1941 */
1942 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1943 *root, struct btrfs_key *ins_key,
1944 struct btrfs_path *path, int data_size, int extend)
1945 {
1946 u64 root_gen;
1947 struct extent_buffer *l;
1948 u32 nritems;
1949 int mid;
1950 int slot;
1951 struct extent_buffer *right;
1952 int space_needed = data_size + sizeof(struct btrfs_item);
1953 int data_copy_size;
1954 int rt_data_off;
1955 int i;
1956 int ret = 0;
1957 int wret;
1958 int double_split;
1959 int num_doubles = 0;
1960 struct btrfs_disk_key disk_key;
1961
1962 if (extend)
1963 space_needed = data_size;
1964
1965 if (root->ref_cows)
1966 root_gen = trans->transid;
1967 else
1968 root_gen = 0;
1969
1970 /* first try to make some room by pushing left and right */
1971 if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
1972 wret = push_leaf_right(trans, root, path, data_size, 0);
1973 if (wret < 0) {
1974 return wret;
1975 }
1976 if (wret) {
1977 wret = push_leaf_left(trans, root, path, data_size, 0);
1978 if (wret < 0)
1979 return wret;
1980 }
1981 l = path->nodes[0];
1982
1983 /* did the pushes work? */
1984 if (btrfs_leaf_free_space(root, l) >= space_needed)
1985 return 0;
1986 }
1987
1988 if (!path->nodes[1]) {
1989 ret = insert_new_root(trans, root, path, 1);
1990 if (ret)
1991 return ret;
1992 }
1993 again:
1994 double_split = 0;
1995 l = path->nodes[0];
1996 slot = path->slots[0];
1997 nritems = btrfs_header_nritems(l);
1998 mid = (nritems + 1)/ 2;
1999
2000 btrfs_item_key(l, &disk_key, 0);
2001
2002 right = __btrfs_alloc_free_block(trans, root, root->leafsize,
2003 root->root_key.objectid,
2004 root_gen, disk_key.objectid, 0,
2005 l->start, 0);
2006 if (IS_ERR(right))
2007 return PTR_ERR(right);
2008
2009 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
2010 btrfs_set_header_bytenr(right, right->start);
2011 btrfs_set_header_generation(right, trans->transid);
2012 btrfs_set_header_owner(right, root->root_key.objectid);
2013 btrfs_set_header_level(right, 0);
2014 write_extent_buffer(right, root->fs_info->fsid,
2015 (unsigned long)btrfs_header_fsid(right),
2016 BTRFS_FSID_SIZE);
2017 if (mid <= slot) {
2018 if (nritems == 1 ||
2019 leaf_space_used(l, mid, nritems - mid) + space_needed >
2020 BTRFS_LEAF_DATA_SIZE(root)) {
2021 if (slot >= nritems) {
2022 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2023 btrfs_set_header_nritems(right, 0);
2024 wret = insert_ptr(trans, root, path,
2025 &disk_key, right->start,
2026 path->slots[1] + 1, 1);
2027 if (wret)
2028 ret = wret;
2029 free_extent_buffer(path->nodes[0]);
2030 path->nodes[0] = right;
2031 path->slots[0] = 0;
2032 path->slots[1] += 1;
2033 return ret;
2034 }
2035 mid = slot;
2036 if (mid != nritems &&
2037 leaf_space_used(l, mid, nritems - mid) +
2038 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2039 double_split = 1;
2040 }
2041 }
2042 } else {
2043 if (leaf_space_used(l, 0, mid + 1) + space_needed >
2044 BTRFS_LEAF_DATA_SIZE(root)) {
2045 if (!extend && slot == 0) {
2046 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2047 btrfs_set_header_nritems(right, 0);
2048 wret = insert_ptr(trans, root, path,
2049 &disk_key,
2050 right->start,
2051 path->slots[1], 1);
2052 if (wret)
2053 ret = wret;
2054 free_extent_buffer(path->nodes[0]);
2055 path->nodes[0] = right;
2056 path->slots[0] = 0;
2057 if (path->slots[1] == 0) {
2058 wret = fixup_low_keys(trans, root,
2059 path, &disk_key, 1);
2060 if (wret)
2061 ret = wret;
2062 }
2063 return ret;
2064 } else if (extend && slot == 0) {
2065 mid = 1;
2066 } else {
2067 mid = slot;
2068 if (mid != nritems &&
2069 leaf_space_used(l, mid, nritems - mid) +
2070 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2071 double_split = 1;
2072 }
2073 }
2074 }
2075 }
2076 nritems = nritems - mid;
2077 btrfs_set_header_nritems(right, nritems);
2078 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
2079
2080 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
2081 btrfs_item_nr_offset(mid),
2082 nritems * sizeof(struct btrfs_item));
2083
2084 copy_extent_buffer(right, l,
2085 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
2086 data_copy_size, btrfs_leaf_data(l) +
2087 leaf_data_end(root, l), data_copy_size);
2088
2089 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
2090 btrfs_item_end_nr(l, mid);
2091
2092 for (i = 0; i < nritems; i++) {
2093 struct btrfs_item *item = btrfs_item_nr(right, i);
2094 u32 ioff;
2095
2096 if (!right->map_token) {
2097 map_extent_buffer(right, (unsigned long)item,
2098 sizeof(struct btrfs_item),
2099 &right->map_token, &right->kaddr,
2100 &right->map_start, &right->map_len,
2101 KM_USER1);
2102 }
2103
2104 ioff = btrfs_item_offset(right, item);
2105 btrfs_set_item_offset(right, item, ioff + rt_data_off);
2106 }
2107
2108 if (right->map_token) {
2109 unmap_extent_buffer(right, right->map_token, KM_USER1);
2110 right->map_token = NULL;
2111 }
2112
2113 btrfs_set_header_nritems(l, mid);
2114 ret = 0;
2115 btrfs_item_key(right, &disk_key, 0);
2116 wret = insert_ptr(trans, root, path, &disk_key, right->start,
2117 path->slots[1] + 1, 1);
2118 if (wret)
2119 ret = wret;
2120
2121 btrfs_mark_buffer_dirty(right);
2122 btrfs_mark_buffer_dirty(l);
2123 BUG_ON(path->slots[0] != slot);
2124
2125 if (mid <= slot) {
2126 free_extent_buffer(path->nodes[0]);
2127 path->nodes[0] = right;
2128 path->slots[0] -= mid;
2129 path->slots[1] += 1;
2130 } else
2131 free_extent_buffer(right);
2132
2133 BUG_ON(path->slots[0] < 0);
2134
2135 if (double_split) {
2136 BUG_ON(num_doubles != 0);
2137 num_doubles++;
2138 goto again;
2139 }
2140 return ret;
2141 }
2142
2143 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
2144 struct btrfs_root *root,
2145 struct btrfs_path *path,
2146 u32 new_size, int from_end)
2147 {
2148 int ret = 0;
2149 int slot;
2150 int slot_orig;
2151 struct extent_buffer *leaf;
2152 struct btrfs_item *item;
2153 u32 nritems;
2154 unsigned int data_end;
2155 unsigned int old_data_start;
2156 unsigned int old_size;
2157 unsigned int size_diff;
2158 int i;
2159
2160 slot_orig = path->slots[0];
2161 leaf = path->nodes[0];
2162 slot = path->slots[0];
2163
2164 old_size = btrfs_item_size_nr(leaf, slot);
2165 if (old_size == new_size)
2166 return 0;
2167
2168 nritems = btrfs_header_nritems(leaf);
2169 data_end = leaf_data_end(root, leaf);
2170
2171 old_data_start = btrfs_item_offset_nr(leaf, slot);
2172
2173 size_diff = old_size - new_size;
2174
2175 BUG_ON(slot < 0);
2176 BUG_ON(slot >= nritems);
2177
2178 /*
2179 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2180 */
2181 /* first correct the data pointers */
2182 for (i = slot; i < nritems; i++) {
2183 u32 ioff;
2184 item = btrfs_item_nr(leaf, i);
2185
2186 if (!leaf->map_token) {
2187 map_extent_buffer(leaf, (unsigned long)item,
2188 sizeof(struct btrfs_item),
2189 &leaf->map_token, &leaf->kaddr,
2190 &leaf->map_start, &leaf->map_len,
2191 KM_USER1);
2192 }
2193
2194 ioff = btrfs_item_offset(leaf, item);
2195 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2196 }
2197
2198 if (leaf->map_token) {
2199 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2200 leaf->map_token = NULL;
2201 }
2202
2203 /* shift the data */
2204 if (from_end) {
2205 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2206 data_end + size_diff, btrfs_leaf_data(leaf) +
2207 data_end, old_data_start + new_size - data_end);
2208 } else {
2209 struct btrfs_disk_key disk_key;
2210 u64 offset;
2211
2212 btrfs_item_key(leaf, &disk_key, slot);
2213
2214 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2215 unsigned long ptr;
2216 struct btrfs_file_extent_item *fi;
2217
2218 fi = btrfs_item_ptr(leaf, slot,
2219 struct btrfs_file_extent_item);
2220 fi = (struct btrfs_file_extent_item *)(
2221 (unsigned long)fi - size_diff);
2222
2223 if (btrfs_file_extent_type(leaf, fi) ==
2224 BTRFS_FILE_EXTENT_INLINE) {
2225 ptr = btrfs_item_ptr_offset(leaf, slot);
2226 memmove_extent_buffer(leaf, ptr,
2227 (unsigned long)fi,
2228 offsetof(struct btrfs_file_extent_item,
2229 disk_bytenr));
2230 }
2231 }
2232
2233 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2234 data_end + size_diff, btrfs_leaf_data(leaf) +
2235 data_end, old_data_start - data_end);
2236
2237 offset = btrfs_disk_key_offset(&disk_key);
2238 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2239 btrfs_set_item_key(leaf, &disk_key, slot);
2240 if (slot == 0)
2241 fixup_low_keys(trans, root, path, &disk_key, 1);
2242 }
2243
2244 item = btrfs_item_nr(leaf, slot);
2245 btrfs_set_item_size(leaf, item, new_size);
2246 btrfs_mark_buffer_dirty(leaf);
2247
2248 ret = 0;
2249 if (btrfs_leaf_free_space(root, leaf) < 0) {
2250 btrfs_print_leaf(root, leaf);
2251 BUG();
2252 }
2253 return ret;
2254 }
2255
2256 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2257 struct btrfs_root *root, struct btrfs_path *path,
2258 u32 data_size)
2259 {
2260 int ret = 0;
2261 int slot;
2262 int slot_orig;
2263 struct extent_buffer *leaf;
2264 struct btrfs_item *item;
2265 u32 nritems;
2266 unsigned int data_end;
2267 unsigned int old_data;
2268 unsigned int old_size;
2269 int i;
2270
2271 slot_orig = path->slots[0];
2272 leaf = path->nodes[0];
2273
2274 nritems = btrfs_header_nritems(leaf);
2275 data_end = leaf_data_end(root, leaf);
2276
2277 if (btrfs_leaf_free_space(root, leaf) < data_size) {
2278 btrfs_print_leaf(root, leaf);
2279 BUG();
2280 }
2281 slot = path->slots[0];
2282 old_data = btrfs_item_end_nr(leaf, slot);
2283
2284 BUG_ON(slot < 0);
2285 if (slot >= nritems) {
2286 btrfs_print_leaf(root, leaf);
2287 printk("slot %d too large, nritems %d\n", slot, nritems);
2288 BUG_ON(1);
2289 }
2290
2291 /*
2292 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2293 */
2294 /* first correct the data pointers */
2295 for (i = slot; i < nritems; i++) {
2296 u32 ioff;
2297 item = btrfs_item_nr(leaf, i);
2298
2299 if (!leaf->map_token) {
2300 map_extent_buffer(leaf, (unsigned long)item,
2301 sizeof(struct btrfs_item),
2302 &leaf->map_token, &leaf->kaddr,
2303 &leaf->map_start, &leaf->map_len,
2304 KM_USER1);
2305 }
2306 ioff = btrfs_item_offset(leaf, item);
2307 btrfs_set_item_offset(leaf, item, ioff - data_size);
2308 }
2309
2310 if (leaf->map_token) {
2311 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2312 leaf->map_token = NULL;
2313 }
2314
2315 /* shift the data */
2316 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2317 data_end - data_size, btrfs_leaf_data(leaf) +
2318 data_end, old_data - data_end);
2319
2320 data_end = old_data;
2321 old_size = btrfs_item_size_nr(leaf, slot);
2322 item = btrfs_item_nr(leaf, slot);
2323 btrfs_set_item_size(leaf, item, old_size + data_size);
2324 btrfs_mark_buffer_dirty(leaf);
2325
2326 ret = 0;
2327 if (btrfs_leaf_free_space(root, leaf) < 0) {
2328 btrfs_print_leaf(root, leaf);
2329 BUG();
2330 }
2331 return ret;
2332 }
2333
2334 /*
2335 * Given a key and some data, insert an item into the tree.
2336 * This does all the path init required, making room in the tree if needed.
2337 */
2338 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
2339 struct btrfs_root *root,
2340 struct btrfs_path *path,
2341 struct btrfs_key *cpu_key, u32 *data_size,
2342 int nr)
2343 {
2344 struct extent_buffer *leaf;
2345 struct btrfs_item *item;
2346 int ret = 0;
2347 int slot;
2348 int slot_orig;
2349 int i;
2350 u32 nritems;
2351 u32 total_size = 0;
2352 u32 total_data = 0;
2353 unsigned int data_end;
2354 struct btrfs_disk_key disk_key;
2355
2356 for (i = 0; i < nr; i++) {
2357 total_data += data_size[i];
2358 }
2359
2360 /* create a root if there isn't one */
2361 if (!root->node)
2362 BUG();
2363
2364 total_size = total_data + (nr - 1) * sizeof(struct btrfs_item);
2365 ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
2366 if (ret == 0) {
2367 return -EEXIST;
2368 }
2369 if (ret < 0)
2370 goto out;
2371
2372 slot_orig = path->slots[0];
2373 leaf = path->nodes[0];
2374
2375 nritems = btrfs_header_nritems(leaf);
2376 data_end = leaf_data_end(root, leaf);
2377
2378 if (btrfs_leaf_free_space(root, leaf) <
2379 sizeof(struct btrfs_item) + total_size) {
2380 btrfs_print_leaf(root, leaf);
2381 printk("not enough freespace need %u have %d\n",
2382 total_size, btrfs_leaf_free_space(root, leaf));
2383 BUG();
2384 }
2385
2386 slot = path->slots[0];
2387 BUG_ON(slot < 0);
2388
2389 if (slot != nritems) {
2390 int i;
2391 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2392
2393 if (old_data < data_end) {
2394 btrfs_print_leaf(root, leaf);
2395 printk("slot %d old_data %d data_end %d\n",
2396 slot, old_data, data_end);
2397 BUG_ON(1);
2398 }
2399 /*
2400 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2401 */
2402 /* first correct the data pointers */
2403 WARN_ON(leaf->map_token);
2404 for (i = slot; i < nritems; i++) {
2405 u32 ioff;
2406
2407 item = btrfs_item_nr(leaf, i);
2408 if (!leaf->map_token) {
2409 map_extent_buffer(leaf, (unsigned long)item,
2410 sizeof(struct btrfs_item),
2411 &leaf->map_token, &leaf->kaddr,
2412 &leaf->map_start, &leaf->map_len,
2413 KM_USER1);
2414 }
2415
2416 ioff = btrfs_item_offset(leaf, item);
2417 btrfs_set_item_offset(leaf, item, ioff - total_data);
2418 }
2419 if (leaf->map_token) {
2420 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2421 leaf->map_token = NULL;
2422 }
2423
2424 /* shift the items */
2425 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
2426 btrfs_item_nr_offset(slot),
2427 (nritems - slot) * sizeof(struct btrfs_item));
2428
2429 /* shift the data */
2430 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2431 data_end - total_data, btrfs_leaf_data(leaf) +
2432 data_end, old_data - data_end);
2433 data_end = old_data;
2434 }
2435
2436 /* setup the item for the new data */
2437 for (i = 0; i < nr; i++) {
2438 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
2439 btrfs_set_item_key(leaf, &disk_key, slot + i);
2440 item = btrfs_item_nr(leaf, slot + i);
2441 btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
2442 data_end -= data_size[i];
2443 btrfs_set_item_size(leaf, item, data_size[i]);
2444 }
2445 btrfs_set_header_nritems(leaf, nritems + nr);
2446 btrfs_mark_buffer_dirty(leaf);
2447
2448 ret = 0;
2449 if (slot == 0) {
2450 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2451 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2452 }
2453
2454 if (btrfs_leaf_free_space(root, leaf) < 0) {
2455 btrfs_print_leaf(root, leaf);
2456 BUG();
2457 }
2458
2459 out:
2460 return ret;
2461 }
2462
2463 /*
2464 * Given a key and some data, insert an item into the tree.
2465 * This does all the path init required, making room in the tree if needed.
2466 */
2467 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2468 *root, struct btrfs_key *cpu_key, void *data, u32
2469 data_size)
2470 {
2471 int ret = 0;
2472 struct btrfs_path *path;
2473 struct extent_buffer *leaf;
2474 unsigned long ptr;
2475
2476 path = btrfs_alloc_path();
2477 BUG_ON(!path);
2478 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2479 if (!ret) {
2480 leaf = path->nodes[0];
2481 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2482 write_extent_buffer(leaf, data, ptr, data_size);
2483 btrfs_mark_buffer_dirty(leaf);
2484 }
2485 btrfs_free_path(path);
2486 return ret;
2487 }
2488
2489 /*
2490 * delete the pointer from a given node.
2491 *
2492 * If the delete empties a node, the node is removed from the tree,
2493 * continuing all the way the root if required. The root is converted into
2494 * a leaf if all the nodes are emptied.
2495 */
2496 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2497 struct btrfs_path *path, int level, int slot)
2498 {
2499 struct extent_buffer *parent = path->nodes[level];
2500 u32 nritems;
2501 int ret = 0;
2502 int wret;
2503
2504 nritems = btrfs_header_nritems(parent);
2505 if (slot != nritems -1) {
2506 memmove_extent_buffer(parent,
2507 btrfs_node_key_ptr_offset(slot),
2508 btrfs_node_key_ptr_offset(slot + 1),
2509 sizeof(struct btrfs_key_ptr) *
2510 (nritems - slot - 1));
2511 }
2512 nritems--;
2513 btrfs_set_header_nritems(parent, nritems);
2514 if (nritems == 0 && parent == root->node) {
2515 BUG_ON(btrfs_header_level(root->node) != 1);
2516 /* just turn the root into a leaf and break */
2517 btrfs_set_header_level(root->node, 0);
2518 } else if (slot == 0) {
2519 struct btrfs_disk_key disk_key;
2520
2521 btrfs_node_key(parent, &disk_key, 0);
2522 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2523 if (wret)
2524 ret = wret;
2525 }
2526 btrfs_mark_buffer_dirty(parent);
2527 return ret;
2528 }
2529
2530 /*
2531 * delete the item at the leaf level in path. If that empties
2532 * the leaf, remove it from the tree
2533 */
2534 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2535 struct btrfs_path *path, int slot, int nr)
2536 {
2537 struct extent_buffer *leaf;
2538 struct btrfs_item *item;
2539 int last_off;
2540 int dsize = 0;
2541 int ret = 0;
2542 int wret;
2543 int i;
2544 u32 nritems;
2545
2546 leaf = path->nodes[0];
2547 last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
2548
2549 for (i = 0; i < nr; i++)
2550 dsize += btrfs_item_size_nr(leaf, slot + i);
2551
2552 nritems = btrfs_header_nritems(leaf);
2553
2554 if (slot + nr != nritems) {
2555 int i;
2556 int data_end = leaf_data_end(root, leaf);
2557
2558 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2559 data_end + dsize,
2560 btrfs_leaf_data(leaf) + data_end,
2561 last_off - data_end);
2562
2563 for (i = slot + nr; i < nritems; i++) {
2564 u32 ioff;
2565
2566 item = btrfs_item_nr(leaf, i);
2567 if (!leaf->map_token) {
2568 map_extent_buffer(leaf, (unsigned long)item,
2569 sizeof(struct btrfs_item),
2570 &leaf->map_token, &leaf->kaddr,
2571 &leaf->map_start, &leaf->map_len,
2572 KM_USER1);
2573 }
2574 ioff = btrfs_item_offset(leaf, item);
2575 btrfs_set_item_offset(leaf, item, ioff + dsize);
2576 }
2577
2578 if (leaf->map_token) {
2579 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2580 leaf->map_token = NULL;
2581 }
2582
2583 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2584 btrfs_item_nr_offset(slot + nr),
2585 sizeof(struct btrfs_item) *
2586 (nritems - slot - nr));
2587 }
2588 btrfs_set_header_nritems(leaf, nritems - nr);
2589 nritems -= nr;
2590
2591 /* delete the leaf if we've emptied it */
2592 if (nritems == 0) {
2593 if (leaf == root->node) {
2594 btrfs_set_header_level(leaf, 0);
2595 } else {
2596 u64 root_gen = btrfs_header_generation(path->nodes[1]);
2597 clean_tree_block(trans, root, leaf);
2598 wait_on_tree_block_writeback(root, leaf);
2599 wret = del_ptr(trans, root, path, 1, path->slots[1]);
2600 if (wret)
2601 ret = wret;
2602 wret = btrfs_free_extent(trans, root,
2603 leaf->start, leaf->len,
2604 btrfs_header_owner(path->nodes[1]),
2605 root_gen, 0, 0, 1);
2606 if (wret)
2607 ret = wret;
2608 }
2609 } else {
2610 int used = leaf_space_used(leaf, 0, nritems);
2611 if (slot == 0) {
2612 struct btrfs_disk_key disk_key;
2613
2614 btrfs_item_key(leaf, &disk_key, 0);
2615 wret = fixup_low_keys(trans, root, path,
2616 &disk_key, 1);
2617 if (wret)
2618 ret = wret;
2619 }
2620
2621 /* delete the leaf if it is mostly empty */
2622 if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
2623 /* push_leaf_left fixes the path.
2624 * make sure the path still points to our leaf
2625 * for possible call to del_ptr below
2626 */
2627 slot = path->slots[1];
2628 extent_buffer_get(leaf);
2629
2630 wret = push_leaf_left(trans, root, path, 1, 1);
2631 if (wret < 0 && wret != -ENOSPC)
2632 ret = wret;
2633
2634 if (path->nodes[0] == leaf &&
2635 btrfs_header_nritems(leaf)) {
2636 wret = push_leaf_right(trans, root, path, 1, 1);
2637 if (wret < 0 && wret != -ENOSPC)
2638 ret = wret;
2639 }
2640
2641 if (btrfs_header_nritems(leaf) == 0) {
2642 u64 root_gen;
2643 u64 bytenr = leaf->start;
2644 u32 blocksize = leaf->len;
2645
2646 root_gen = btrfs_header_generation(
2647 path->nodes[1]);
2648
2649 clean_tree_block(trans, root, leaf);
2650 wait_on_tree_block_writeback(root, leaf);
2651
2652 wret = del_ptr(trans, root, path, 1, slot);
2653 if (wret)
2654 ret = wret;
2655
2656 free_extent_buffer(leaf);
2657 wret = btrfs_free_extent(trans, root, bytenr,
2658 blocksize,
2659 btrfs_header_owner(path->nodes[1]),
2660 root_gen, 0, 0, 1);
2661 if (wret)
2662 ret = wret;
2663 } else {
2664 btrfs_mark_buffer_dirty(leaf);
2665 free_extent_buffer(leaf);
2666 }
2667 } else {
2668 btrfs_mark_buffer_dirty(leaf);
2669 }
2670 }
2671 return ret;
2672 }
2673
2674 /*
2675 * walk up the tree as far as required to find the previous leaf.
2676 * returns 0 if it found something or 1 if there are no lesser leaves.
2677 * returns < 0 on io errors.
2678 */
2679 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
2680 {
2681 u64 bytenr;
2682 int slot;
2683 int level = 1;
2684 struct extent_buffer *c;
2685 struct extent_buffer *next = NULL;
2686
2687 while(level < BTRFS_MAX_LEVEL) {
2688 if (!path->nodes[level])
2689 return 1;
2690
2691 slot = path->slots[level];
2692 c = path->nodes[level];
2693 if (slot == 0) {
2694 level++;
2695 if (level == BTRFS_MAX_LEVEL)
2696 return 1;
2697 continue;
2698 }
2699 slot--;
2700
2701 bytenr = btrfs_node_blockptr(c, slot);
2702 if (next)
2703 free_extent_buffer(next);
2704
2705 next = read_tree_block(root, bytenr,
2706 btrfs_level_size(root, level - 1));
2707 break;
2708 }
2709 path->slots[level] = slot;
2710 while(1) {
2711 level--;
2712 c = path->nodes[level];
2713 free_extent_buffer(c);
2714 slot = btrfs_header_nritems(next);
2715 if (slot != 0)
2716 slot--;
2717 path->nodes[level] = next;
2718 path->slots[level] = slot;
2719 if (!level)
2720 break;
2721 next = read_tree_block(root, btrfs_node_blockptr(next, slot),
2722 btrfs_level_size(root, level - 1));
2723 }
2724 return 0;
2725 }
2726
2727 /*
2728 * walk up the tree as far as required to find the next leaf.
2729 * returns 0 if it found something or 1 if there are no greater leaves.
2730 * returns < 0 on io errors.
2731 */
2732 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2733 {
2734 int slot;
2735 int level = 1;
2736 u64 bytenr;
2737 struct extent_buffer *c;
2738 struct extent_buffer *next = NULL;
2739
2740 while(level < BTRFS_MAX_LEVEL) {
2741 if (!path->nodes[level])
2742 return 1;
2743
2744 slot = path->slots[level] + 1;
2745 c = path->nodes[level];
2746 if (slot >= btrfs_header_nritems(c)) {
2747 level++;
2748 if (level == BTRFS_MAX_LEVEL)
2749 return 1;
2750 continue;
2751 }
2752
2753 bytenr = btrfs_node_blockptr(c, slot);
2754 if (next)
2755 free_extent_buffer(next);
2756
2757 if (path->reada)
2758 reada_for_search(root, path, level, slot, 0);
2759
2760 next = read_tree_block(root, bytenr,
2761 btrfs_level_size(root, level -1));
2762 break;
2763 }
2764 path->slots[level] = slot;
2765 while(1) {
2766 level--;
2767 c = path->nodes[level];
2768 free_extent_buffer(c);
2769 path->nodes[level] = next;
2770 path->slots[level] = 0;
2771 if (!level)
2772 break;
2773 if (path->reada)
2774 reada_for_search(root, path, level, 0, 0);
2775 next = read_tree_block(root, btrfs_node_blockptr(next, 0),
2776 btrfs_level_size(root, level - 1));
2777 }
2778 return 0;
2779 }
Linux kernel - Deliverables
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