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Btrfs: Disable extra debugging checks on tree blocks
[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 static void add_root_to_dirty_list(struct btrfs_root *root)
74 {
75 if (root->track_dirty && list_empty(&root->dirty_list)) {
76 list_add(&root->dirty_list,
77 &root->fs_info->dirty_cowonly_roots);
78 }
79 }
80
81 int btrfs_copy_root(struct btrfs_trans_handle *trans,
82 struct btrfs_root *root,
83 struct extent_buffer *buf,
84 struct extent_buffer **cow_ret, u64 new_root_objectid)
85 {
86 struct extent_buffer *cow;
87 u32 nritems;
88 int ret = 0;
89 int level;
90 struct btrfs_key first_key;
91 struct btrfs_root *new_root;
92
93 new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
94 if (!new_root)
95 return -ENOMEM;
96
97 memcpy(new_root, root, sizeof(*new_root));
98 new_root->root_key.objectid = new_root_objectid;
99
100 WARN_ON(root->ref_cows && trans->transid !=
101 root->fs_info->running_transaction->transid);
102 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
103
104 level = btrfs_header_level(buf);
105 nritems = btrfs_header_nritems(buf);
106 if (nritems) {
107 if (level == 0)
108 btrfs_item_key_to_cpu(buf, &first_key, 0);
109 else
110 btrfs_node_key_to_cpu(buf, &first_key, 0);
111 } else {
112 first_key.objectid = 0;
113 }
114 cow = __btrfs_alloc_free_block(trans, new_root, buf->len,
115 new_root_objectid,
116 trans->transid, first_key.objectid,
117 level, buf->start, 0);
118 if (IS_ERR(cow)) {
119 kfree(new_root);
120 return PTR_ERR(cow);
121 }
122
123 copy_extent_buffer(cow, buf, 0, 0, cow->len);
124 btrfs_set_header_bytenr(cow, cow->start);
125 btrfs_set_header_generation(cow, trans->transid);
126 btrfs_set_header_owner(cow, new_root_objectid);
127 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
128
129 WARN_ON(btrfs_header_generation(buf) > trans->transid);
130 ret = btrfs_inc_ref(trans, new_root, buf);
131 kfree(new_root);
132
133 if (ret)
134 return ret;
135
136 btrfs_mark_buffer_dirty(cow);
137 *cow_ret = cow;
138 return 0;
139 }
140
141 int __btrfs_cow_block(struct btrfs_trans_handle *trans,
142 struct btrfs_root *root,
143 struct extent_buffer *buf,
144 struct extent_buffer *parent, int parent_slot,
145 struct extent_buffer **cow_ret,
146 u64 search_start, u64 empty_size)
147 {
148 u64 root_gen;
149 struct extent_buffer *cow;
150 u32 nritems;
151 int ret = 0;
152 int different_trans = 0;
153 int level;
154 struct btrfs_key first_key;
155
156 if (root->ref_cows) {
157 root_gen = trans->transid;
158 } else {
159 root_gen = 0;
160 }
161 WARN_ON(root->ref_cows && trans->transid !=
162 root->fs_info->running_transaction->transid);
163 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
164
165 level = btrfs_header_level(buf);
166 nritems = btrfs_header_nritems(buf);
167 if (nritems) {
168 if (level == 0)
169 btrfs_item_key_to_cpu(buf, &first_key, 0);
170 else
171 btrfs_node_key_to_cpu(buf, &first_key, 0);
172 } else {
173 first_key.objectid = 0;
174 }
175 cow = __btrfs_alloc_free_block(trans, root, buf->len,
176 root->root_key.objectid,
177 root_gen, first_key.objectid, level,
178 search_start, empty_size);
179 if (IS_ERR(cow))
180 return PTR_ERR(cow);
181
182 copy_extent_buffer(cow, buf, 0, 0, cow->len);
183 btrfs_set_header_bytenr(cow, cow->start);
184 btrfs_set_header_generation(cow, trans->transid);
185 btrfs_set_header_owner(cow, root->root_key.objectid);
186 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
187
188 WARN_ON(btrfs_header_generation(buf) > trans->transid);
189 if (btrfs_header_generation(buf) != trans->transid) {
190 different_trans = 1;
191 ret = btrfs_inc_ref(trans, root, buf);
192 if (ret)
193 return ret;
194 } else {
195 clean_tree_block(trans, root, buf);
196 }
197
198 if (buf == root->node) {
199 root_gen = btrfs_header_generation(buf);
200 root->node = cow;
201 extent_buffer_get(cow);
202 if (buf != root->commit_root) {
203 btrfs_free_extent(trans, root, buf->start,
204 buf->len, root->root_key.objectid,
205 root_gen, 0, 0, 1);
206 }
207 free_extent_buffer(buf);
208 add_root_to_dirty_list(root);
209 } else {
210 root_gen = btrfs_header_generation(parent);
211 btrfs_set_node_blockptr(parent, parent_slot,
212 cow->start);
213 WARN_ON(trans->transid == 0);
214 btrfs_set_node_ptr_generation(parent, parent_slot,
215 trans->transid);
216 btrfs_mark_buffer_dirty(parent);
217 WARN_ON(btrfs_header_generation(parent) != trans->transid);
218 btrfs_free_extent(trans, root, buf->start, buf->len,
219 btrfs_header_owner(parent), root_gen,
220 0, 0, 1);
221 }
222 free_extent_buffer(buf);
223 btrfs_mark_buffer_dirty(cow);
224 *cow_ret = cow;
225 return 0;
226 }
227
228 int btrfs_cow_block(struct btrfs_trans_handle *trans,
229 struct btrfs_root *root, struct extent_buffer *buf,
230 struct extent_buffer *parent, int parent_slot,
231 struct extent_buffer **cow_ret)
232 {
233 u64 search_start;
234 u64 header_trans;
235 int ret;
236
237 if (trans->transaction != root->fs_info->running_transaction) {
238 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
239 root->fs_info->running_transaction->transid);
240 WARN_ON(1);
241 }
242 if (trans->transid != root->fs_info->generation) {
243 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
244 root->fs_info->generation);
245 WARN_ON(1);
246 }
247
248 header_trans = btrfs_header_generation(buf);
249 spin_lock(&root->fs_info->hash_lock);
250 if (header_trans == trans->transid &&
251 !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
252 *cow_ret = buf;
253 spin_unlock(&root->fs_info->hash_lock);
254 return 0;
255 }
256 spin_unlock(&root->fs_info->hash_lock);
257 search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
258 ret = __btrfs_cow_block(trans, root, buf, parent,
259 parent_slot, cow_ret, search_start, 0);
260 return ret;
261 }
262
263 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
264 {
265 if (blocknr < other && other - (blocknr + blocksize) < 32768)
266 return 1;
267 if (blocknr > other && blocknr - (other + blocksize) < 32768)
268 return 1;
269 return 0;
270 }
271
272 /*
273 * compare two keys in a memcmp fashion
274 */
275 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
276 {
277 struct btrfs_key k1;
278
279 btrfs_disk_key_to_cpu(&k1, disk);
280
281 if (k1.objectid > k2->objectid)
282 return 1;
283 if (k1.objectid < k2->objectid)
284 return -1;
285 if (k1.type > k2->type)
286 return 1;
287 if (k1.type < k2->type)
288 return -1;
289 if (k1.offset > k2->offset)
290 return 1;
291 if (k1.offset < k2->offset)
292 return -1;
293 return 0;
294 }
295
296
297 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
298 struct btrfs_root *root, struct extent_buffer *parent,
299 int start_slot, int cache_only, u64 *last_ret,
300 struct btrfs_key *progress)
301 {
302 struct extent_buffer *cur;
303 struct extent_buffer *tmp;
304 u64 blocknr;
305 u64 search_start = *last_ret;
306 u64 last_block = 0;
307 u64 other;
308 u32 parent_nritems;
309 int end_slot;
310 int i;
311 int err = 0;
312 int parent_level;
313 int uptodate;
314 u32 blocksize;
315 int progress_passed = 0;
316 struct btrfs_disk_key disk_key;
317
318 parent_level = btrfs_header_level(parent);
319 if (cache_only && parent_level != 1)
320 return 0;
321
322 if (trans->transaction != root->fs_info->running_transaction) {
323 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
324 root->fs_info->running_transaction->transid);
325 WARN_ON(1);
326 }
327 if (trans->transid != root->fs_info->generation) {
328 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
329 root->fs_info->generation);
330 WARN_ON(1);
331 }
332
333 parent_nritems = btrfs_header_nritems(parent);
334 blocksize = btrfs_level_size(root, parent_level - 1);
335 end_slot = parent_nritems;
336
337 if (parent_nritems == 1)
338 return 0;
339
340 for (i = start_slot; i < end_slot; i++) {
341 int close = 1;
342
343 if (!parent->map_token) {
344 map_extent_buffer(parent,
345 btrfs_node_key_ptr_offset(i),
346 sizeof(struct btrfs_key_ptr),
347 &parent->map_token, &parent->kaddr,
348 &parent->map_start, &parent->map_len,
349 KM_USER1);
350 }
351 btrfs_node_key(parent, &disk_key, i);
352 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
353 continue;
354
355 progress_passed = 1;
356 blocknr = btrfs_node_blockptr(parent, i);
357 if (last_block == 0)
358 last_block = blocknr;
359
360 if (i > 0) {
361 other = btrfs_node_blockptr(parent, i - 1);
362 close = close_blocks(blocknr, other, blocksize);
363 }
364 if (close && i < end_slot - 2) {
365 other = btrfs_node_blockptr(parent, i + 1);
366 close = close_blocks(blocknr, other, blocksize);
367 }
368 if (close) {
369 last_block = blocknr;
370 continue;
371 }
372 if (parent->map_token) {
373 unmap_extent_buffer(parent, parent->map_token,
374 KM_USER1);
375 parent->map_token = NULL;
376 }
377
378 cur = btrfs_find_tree_block(root, blocknr, blocksize);
379 if (cur)
380 uptodate = btrfs_buffer_uptodate(cur);
381 else
382 uptodate = 0;
383 if (!cur || !uptodate) {
384 if (cache_only) {
385 free_extent_buffer(cur);
386 continue;
387 }
388 if (!cur) {
389 cur = read_tree_block(root, blocknr,
390 blocksize);
391 } else if (!uptodate) {
392 btrfs_read_buffer(cur);
393 }
394 }
395 if (search_start == 0)
396 search_start = last_block;
397
398 btrfs_verify_block_csum(root, cur);
399 err = __btrfs_cow_block(trans, root, cur, parent, i,
400 &tmp, search_start,
401 min(16 * blocksize,
402 (end_slot - i) * blocksize));
403 if (err) {
404 free_extent_buffer(cur);
405 break;
406 }
407 search_start = tmp->start;
408 last_block = tmp->start;
409 *last_ret = search_start;
410 if (parent_level == 1)
411 btrfs_clear_buffer_defrag(tmp);
412 free_extent_buffer(tmp);
413 }
414 if (parent->map_token) {
415 unmap_extent_buffer(parent, parent->map_token,
416 KM_USER1);
417 parent->map_token = NULL;
418 }
419 return err;
420 }
421
422 /*
423 * The leaf data grows from end-to-front in the node.
424 * this returns the address of the start of the last item,
425 * which is the stop of the leaf data stack
426 */
427 static inline unsigned int leaf_data_end(struct btrfs_root *root,
428 struct extent_buffer *leaf)
429 {
430 u32 nr = btrfs_header_nritems(leaf);
431 if (nr == 0)
432 return BTRFS_LEAF_DATA_SIZE(root);
433 return btrfs_item_offset_nr(leaf, nr - 1);
434 }
435
436 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
437 int level)
438 {
439 struct extent_buffer *parent = NULL;
440 struct extent_buffer *node = path->nodes[level];
441 struct btrfs_disk_key parent_key;
442 struct btrfs_disk_key node_key;
443 int parent_slot;
444 int slot;
445 struct btrfs_key cpukey;
446 u32 nritems = btrfs_header_nritems(node);
447
448 if (path->nodes[level + 1])
449 parent = path->nodes[level + 1];
450
451 slot = path->slots[level];
452 BUG_ON(nritems == 0);
453 if (parent) {
454 parent_slot = path->slots[level + 1];
455 btrfs_node_key(parent, &parent_key, parent_slot);
456 btrfs_node_key(node, &node_key, 0);
457 BUG_ON(memcmp(&parent_key, &node_key,
458 sizeof(struct btrfs_disk_key)));
459 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
460 btrfs_header_bytenr(node));
461 }
462 BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
463 if (slot != 0) {
464 btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
465 btrfs_node_key(node, &node_key, slot);
466 BUG_ON(comp_keys(&node_key, &cpukey) <= 0);
467 }
468 if (slot < nritems - 1) {
469 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
470 btrfs_node_key(node, &node_key, slot);
471 BUG_ON(comp_keys(&node_key, &cpukey) >= 0);
472 }
473 return 0;
474 }
475
476 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
477 int level)
478 {
479 struct extent_buffer *leaf = path->nodes[level];
480 struct extent_buffer *parent = NULL;
481 int parent_slot;
482 struct btrfs_key cpukey;
483 struct btrfs_disk_key parent_key;
484 struct btrfs_disk_key leaf_key;
485 int slot = path->slots[0];
486
487 u32 nritems = btrfs_header_nritems(leaf);
488
489 if (path->nodes[level + 1])
490 parent = path->nodes[level + 1];
491
492 if (nritems == 0)
493 return 0;
494
495 if (parent) {
496 parent_slot = path->slots[level + 1];
497 btrfs_node_key(parent, &parent_key, parent_slot);
498 btrfs_item_key(leaf, &leaf_key, 0);
499
500 BUG_ON(memcmp(&parent_key, &leaf_key,
501 sizeof(struct btrfs_disk_key)));
502 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
503 btrfs_header_bytenr(leaf));
504 }
505 #if 0
506 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
507 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
508 btrfs_item_key(leaf, &leaf_key, i);
509 if (comp_keys(&leaf_key, &cpukey) >= 0) {
510 btrfs_print_leaf(root, leaf);
511 printk("slot %d offset bad key\n", i);
512 BUG_ON(1);
513 }
514 if (btrfs_item_offset_nr(leaf, i) !=
515 btrfs_item_end_nr(leaf, i + 1)) {
516 btrfs_print_leaf(root, leaf);
517 printk("slot %d offset bad\n", i);
518 BUG_ON(1);
519 }
520 if (i == 0) {
521 if (btrfs_item_offset_nr(leaf, i) +
522 btrfs_item_size_nr(leaf, i) !=
523 BTRFS_LEAF_DATA_SIZE(root)) {
524 btrfs_print_leaf(root, leaf);
525 printk("slot %d first offset bad\n", i);
526 BUG_ON(1);
527 }
528 }
529 }
530 if (nritems > 0) {
531 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
532 btrfs_print_leaf(root, leaf);
533 printk("slot %d bad size \n", nritems - 1);
534 BUG_ON(1);
535 }
536 }
537 #endif
538 if (slot != 0 && slot < nritems - 1) {
539 btrfs_item_key(leaf, &leaf_key, slot);
540 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
541 if (comp_keys(&leaf_key, &cpukey) <= 0) {
542 btrfs_print_leaf(root, leaf);
543 printk("slot %d offset bad key\n", slot);
544 BUG_ON(1);
545 }
546 if (btrfs_item_offset_nr(leaf, slot - 1) !=
547 btrfs_item_end_nr(leaf, slot)) {
548 btrfs_print_leaf(root, leaf);
549 printk("slot %d offset bad\n", slot);
550 BUG_ON(1);
551 }
552 }
553 if (slot < nritems - 1) {
554 btrfs_item_key(leaf, &leaf_key, slot);
555 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
556 BUG_ON(comp_keys(&leaf_key, &cpukey) >= 0);
557 if (btrfs_item_offset_nr(leaf, slot) !=
558 btrfs_item_end_nr(leaf, slot + 1)) {
559 btrfs_print_leaf(root, leaf);
560 printk("slot %d offset bad\n", slot);
561 BUG_ON(1);
562 }
563 }
564 BUG_ON(btrfs_item_offset_nr(leaf, 0) +
565 btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
566 return 0;
567 }
568
569 static int noinline check_block(struct btrfs_root *root,
570 struct btrfs_path *path, int level)
571 {
572 u64 found_start;
573 return 0;
574 if (btrfs_header_level(path->nodes[level]) != level)
575 printk("warning: bad level %Lu wanted %d found %d\n",
576 path->nodes[level]->start, level,
577 btrfs_header_level(path->nodes[level]));
578 found_start = btrfs_header_bytenr(path->nodes[level]);
579 if (found_start != path->nodes[level]->start) {
580 printk("warning: bad bytentr %Lu found %Lu\n",
581 path->nodes[level]->start, found_start);
582 }
583 #if 0
584 struct extent_buffer *buf = path->nodes[level];
585
586 if (memcmp_extent_buffer(buf, root->fs_info->fsid,
587 (unsigned long)btrfs_header_fsid(buf),
588 BTRFS_FSID_SIZE)) {
589 printk("warning bad block %Lu\n", buf->start);
590 return 1;
591 }
592 #endif
593 if (level == 0)
594 return check_leaf(root, path, level);
595 return check_node(root, path, level);
596 }
597
598 /*
599 * search for key in the extent_buffer. The items start at offset p,
600 * and they are item_size apart. There are 'max' items in p.
601 *
602 * the slot in the array is returned via slot, and it points to
603 * the place where you would insert key if it is not found in
604 * the array.
605 *
606 * slot may point to max if the key is bigger than all of the keys
607 */
608 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
609 int item_size, struct btrfs_key *key,
610 int max, int *slot)
611 {
612 int low = 0;
613 int high = max;
614 int mid;
615 int ret;
616 struct btrfs_disk_key *tmp = NULL;
617 struct btrfs_disk_key unaligned;
618 unsigned long offset;
619 char *map_token = NULL;
620 char *kaddr = NULL;
621 unsigned long map_start = 0;
622 unsigned long map_len = 0;
623 int err;
624
625 while(low < high) {
626 mid = (low + high) / 2;
627 offset = p + mid * item_size;
628
629 if (!map_token || offset < map_start ||
630 (offset + sizeof(struct btrfs_disk_key)) >
631 map_start + map_len) {
632 if (map_token) {
633 unmap_extent_buffer(eb, map_token, KM_USER0);
634 map_token = NULL;
635 }
636 err = map_extent_buffer(eb, offset,
637 sizeof(struct btrfs_disk_key),
638 &map_token, &kaddr,
639 &map_start, &map_len, KM_USER0);
640
641 if (!err) {
642 tmp = (struct btrfs_disk_key *)(kaddr + offset -
643 map_start);
644 } else {
645 read_extent_buffer(eb, &unaligned,
646 offset, sizeof(unaligned));
647 tmp = &unaligned;
648 }
649
650 } else {
651 tmp = (struct btrfs_disk_key *)(kaddr + offset -
652 map_start);
653 }
654 ret = comp_keys(tmp, key);
655
656 if (ret < 0)
657 low = mid + 1;
658 else if (ret > 0)
659 high = mid;
660 else {
661 *slot = mid;
662 if (map_token)
663 unmap_extent_buffer(eb, map_token, KM_USER0);
664 return 0;
665 }
666 }
667 *slot = low;
668 if (map_token)
669 unmap_extent_buffer(eb, map_token, KM_USER0);
670 return 1;
671 }
672
673 /*
674 * simple bin_search frontend that does the right thing for
675 * leaves vs nodes
676 */
677 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
678 int level, int *slot)
679 {
680 if (level == 0) {
681 return generic_bin_search(eb,
682 offsetof(struct btrfs_leaf, items),
683 sizeof(struct btrfs_item),
684 key, btrfs_header_nritems(eb),
685 slot);
686 } else {
687 return generic_bin_search(eb,
688 offsetof(struct btrfs_node, ptrs),
689 sizeof(struct btrfs_key_ptr),
690 key, btrfs_header_nritems(eb),
691 slot);
692 }
693 return -1;
694 }
695
696 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
697 struct extent_buffer *parent, int slot)
698 {
699 if (slot < 0)
700 return NULL;
701 if (slot >= btrfs_header_nritems(parent))
702 return NULL;
703 return read_tree_block(root, btrfs_node_blockptr(parent, slot),
704 btrfs_level_size(root, btrfs_header_level(parent) - 1));
705 }
706
707 static int balance_level(struct btrfs_trans_handle *trans,
708 struct btrfs_root *root,
709 struct btrfs_path *path, int level)
710 {
711 struct extent_buffer *right = NULL;
712 struct extent_buffer *mid;
713 struct extent_buffer *left = NULL;
714 struct extent_buffer *parent = NULL;
715 int ret = 0;
716 int wret;
717 int pslot;
718 int orig_slot = path->slots[level];
719 int err_on_enospc = 0;
720 u64 orig_ptr;
721
722 if (level == 0)
723 return 0;
724
725 mid = path->nodes[level];
726 WARN_ON(btrfs_header_generation(mid) != trans->transid);
727
728 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
729
730 if (level < BTRFS_MAX_LEVEL - 1)
731 parent = path->nodes[level + 1];
732 pslot = path->slots[level + 1];
733
734 /*
735 * deal with the case where there is only one pointer in the root
736 * by promoting the node below to a root
737 */
738 if (!parent) {
739 struct extent_buffer *child;
740
741 if (btrfs_header_nritems(mid) != 1)
742 return 0;
743
744 /* promote the child to a root */
745 child = read_node_slot(root, mid, 0);
746 BUG_ON(!child);
747 ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
748 BUG_ON(ret);
749
750 root->node = child;
751 add_root_to_dirty_list(root);
752 path->nodes[level] = NULL;
753 clean_tree_block(trans, root, mid);
754 wait_on_tree_block_writeback(root, mid);
755 /* once for the path */
756 free_extent_buffer(mid);
757 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
758 root->root_key.objectid,
759 btrfs_header_generation(mid), 0, 0, 1);
760 /* once for the root ptr */
761 free_extent_buffer(mid);
762 return ret;
763 }
764 if (btrfs_header_nritems(mid) >
765 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
766 return 0;
767
768 if (btrfs_header_nritems(mid) < 2)
769 err_on_enospc = 1;
770
771 left = read_node_slot(root, parent, pslot - 1);
772 if (left) {
773 wret = btrfs_cow_block(trans, root, left,
774 parent, pslot - 1, &left);
775 if (wret) {
776 ret = wret;
777 goto enospc;
778 }
779 }
780 right = read_node_slot(root, parent, pslot + 1);
781 if (right) {
782 wret = btrfs_cow_block(trans, root, right,
783 parent, pslot + 1, &right);
784 if (wret) {
785 ret = wret;
786 goto enospc;
787 }
788 }
789
790 /* first, try to make some room in the middle buffer */
791 if (left) {
792 orig_slot += btrfs_header_nritems(left);
793 wret = push_node_left(trans, root, left, mid);
794 if (wret < 0)
795 ret = wret;
796 if (btrfs_header_nritems(mid) < 2)
797 err_on_enospc = 1;
798 }
799
800 /*
801 * then try to empty the right most buffer into the middle
802 */
803 if (right) {
804 wret = push_node_left(trans, root, mid, right);
805 if (wret < 0 && wret != -ENOSPC)
806 ret = wret;
807 if (btrfs_header_nritems(right) == 0) {
808 u64 bytenr = right->start;
809 u64 generation = btrfs_header_generation(parent);
810 u32 blocksize = right->len;
811
812 clean_tree_block(trans, root, right);
813 wait_on_tree_block_writeback(root, right);
814 free_extent_buffer(right);
815 right = NULL;
816 wret = del_ptr(trans, root, path, level + 1, pslot +
817 1);
818 if (wret)
819 ret = wret;
820 wret = btrfs_free_extent(trans, root, bytenr,
821 blocksize,
822 btrfs_header_owner(parent),
823 generation, 0, 0, 1);
824 if (wret)
825 ret = wret;
826 } else {
827 struct btrfs_disk_key right_key;
828 btrfs_node_key(right, &right_key, 0);
829 btrfs_set_node_key(parent, &right_key, pslot + 1);
830 btrfs_mark_buffer_dirty(parent);
831 }
832 }
833 if (btrfs_header_nritems(mid) == 1) {
834 /*
835 * we're not allowed to leave a node with one item in the
836 * tree during a delete. A deletion from lower in the tree
837 * could try to delete the only pointer in this node.
838 * So, pull some keys from the left.
839 * There has to be a left pointer at this point because
840 * otherwise we would have pulled some pointers from the
841 * right
842 */
843 BUG_ON(!left);
844 wret = balance_node_right(trans, root, mid, left);
845 if (wret < 0) {
846 ret = wret;
847 goto enospc;
848 }
849 BUG_ON(wret == 1);
850 }
851 if (btrfs_header_nritems(mid) == 0) {
852 /* we've managed to empty the middle node, drop it */
853 u64 root_gen = btrfs_header_generation(parent);
854 u64 bytenr = mid->start;
855 u32 blocksize = mid->len;
856 clean_tree_block(trans, root, mid);
857 wait_on_tree_block_writeback(root, mid);
858 free_extent_buffer(mid);
859 mid = NULL;
860 wret = del_ptr(trans, root, path, level + 1, pslot);
861 if (wret)
862 ret = wret;
863 wret = btrfs_free_extent(trans, root, bytenr, blocksize,
864 btrfs_header_owner(parent),
865 root_gen, 0, 0, 1);
866 if (wret)
867 ret = wret;
868 } else {
869 /* update the parent key to reflect our changes */
870 struct btrfs_disk_key mid_key;
871 btrfs_node_key(mid, &mid_key, 0);
872 btrfs_set_node_key(parent, &mid_key, pslot);
873 btrfs_mark_buffer_dirty(parent);
874 }
875
876 /* update the path */
877 if (left) {
878 if (btrfs_header_nritems(left) > orig_slot) {
879 extent_buffer_get(left);
880 path->nodes[level] = left;
881 path->slots[level + 1] -= 1;
882 path->slots[level] = orig_slot;
883 if (mid)
884 free_extent_buffer(mid);
885 } else {
886 orig_slot -= btrfs_header_nritems(left);
887 path->slots[level] = orig_slot;
888 }
889 }
890 /* double check we haven't messed things up */
891 check_block(root, path, level);
892 if (orig_ptr !=
893 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
894 BUG();
895 enospc:
896 if (right)
897 free_extent_buffer(right);
898 if (left)
899 free_extent_buffer(left);
900 return ret;
901 }
902
903 /* returns zero if the push worked, non-zero otherwise */
904 static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
905 struct btrfs_root *root,
906 struct btrfs_path *path, int level)
907 {
908 struct extent_buffer *right = NULL;
909 struct extent_buffer *mid;
910 struct extent_buffer *left = NULL;
911 struct extent_buffer *parent = NULL;
912 int ret = 0;
913 int wret;
914 int pslot;
915 int orig_slot = path->slots[level];
916 u64 orig_ptr;
917
918 if (level == 0)
919 return 1;
920
921 mid = path->nodes[level];
922 WARN_ON(btrfs_header_generation(mid) != trans->transid);
923 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
924
925 if (level < BTRFS_MAX_LEVEL - 1)
926 parent = path->nodes[level + 1];
927 pslot = path->slots[level + 1];
928
929 if (!parent)
930 return 1;
931
932 left = read_node_slot(root, parent, pslot - 1);
933
934 /* first, try to make some room in the middle buffer */
935 if (left) {
936 u32 left_nr;
937 left_nr = btrfs_header_nritems(left);
938 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
939 wret = 1;
940 } else {
941 ret = btrfs_cow_block(trans, root, left, parent,
942 pslot - 1, &left);
943 if (ret)
944 wret = 1;
945 else {
946 wret = push_node_left(trans, root,
947 left, mid);
948 }
949 }
950 if (wret < 0)
951 ret = wret;
952 if (wret == 0) {
953 struct btrfs_disk_key disk_key;
954 orig_slot += left_nr;
955 btrfs_node_key(mid, &disk_key, 0);
956 btrfs_set_node_key(parent, &disk_key, pslot);
957 btrfs_mark_buffer_dirty(parent);
958 if (btrfs_header_nritems(left) > orig_slot) {
959 path->nodes[level] = left;
960 path->slots[level + 1] -= 1;
961 path->slots[level] = orig_slot;
962 free_extent_buffer(mid);
963 } else {
964 orig_slot -=
965 btrfs_header_nritems(left);
966 path->slots[level] = orig_slot;
967 free_extent_buffer(left);
968 }
969 return 0;
970 }
971 free_extent_buffer(left);
972 }
973 right= read_node_slot(root, parent, pslot + 1);
974
975 /*
976 * then try to empty the right most buffer into the middle
977 */
978 if (right) {
979 u32 right_nr;
980 right_nr = btrfs_header_nritems(right);
981 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
982 wret = 1;
983 } else {
984 ret = btrfs_cow_block(trans, root, right,
985 parent, pslot + 1,
986 &right);
987 if (ret)
988 wret = 1;
989 else {
990 wret = balance_node_right(trans, root,
991 right, mid);
992 }
993 }
994 if (wret < 0)
995 ret = wret;
996 if (wret == 0) {
997 struct btrfs_disk_key disk_key;
998
999 btrfs_node_key(right, &disk_key, 0);
1000 btrfs_set_node_key(parent, &disk_key, pslot + 1);
1001 btrfs_mark_buffer_dirty(parent);
1002
1003 if (btrfs_header_nritems(mid) <= orig_slot) {
1004 path->nodes[level] = right;
1005 path->slots[level + 1] += 1;
1006 path->slots[level] = orig_slot -
1007 btrfs_header_nritems(mid);
1008 free_extent_buffer(mid);
1009 } else {
1010 free_extent_buffer(right);
1011 }
1012 return 0;
1013 }
1014 free_extent_buffer(right);
1015 }
1016 return 1;
1017 }
1018
1019 /*
1020 * readahead one full node of leaves
1021 */
1022 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
1023 int level, int slot, u64 objectid)
1024 {
1025 struct extent_buffer *node;
1026 struct btrfs_disk_key disk_key;
1027 u32 nritems;
1028 u64 search;
1029 u64 lowest_read;
1030 u64 highest_read;
1031 u64 nread = 0;
1032 int direction = path->reada;
1033 struct extent_buffer *eb;
1034 u32 nr;
1035 u32 blocksize;
1036 u32 nscan = 0;
1037
1038 if (level != 1)
1039 return;
1040
1041 if (!path->nodes[level])
1042 return;
1043
1044 node = path->nodes[level];
1045 search = btrfs_node_blockptr(node, slot);
1046 blocksize = btrfs_level_size(root, level - 1);
1047 eb = btrfs_find_tree_block(root, search, blocksize);
1048 if (eb) {
1049 free_extent_buffer(eb);
1050 return;
1051 }
1052
1053 highest_read = search;
1054 lowest_read = search;
1055
1056 nritems = btrfs_header_nritems(node);
1057 nr = slot;
1058 while(1) {
1059 if (direction < 0) {
1060 if (nr == 0)
1061 break;
1062 nr--;
1063 } else if (direction > 0) {
1064 nr++;
1065 if (nr >= nritems)
1066 break;
1067 }
1068 if (path->reada < 0 && objectid) {
1069 btrfs_node_key(node, &disk_key, nr);
1070 if (btrfs_disk_key_objectid(&disk_key) != objectid)
1071 break;
1072 }
1073 search = btrfs_node_blockptr(node, nr);
1074 if ((search >= lowest_read && search <= highest_read) ||
1075 (search < lowest_read && lowest_read - search <= 32768) ||
1076 (search > highest_read && search - highest_read <= 32768)) {
1077 readahead_tree_block(root, search, blocksize);
1078 nread += blocksize;
1079 }
1080 nscan++;
1081 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
1082 break;
1083 if(nread > (1024 * 1024) || nscan > 128)
1084 break;
1085
1086 if (search < lowest_read)
1087 lowest_read = search;
1088 if (search > highest_read)
1089 highest_read = search;
1090 }
1091 }
1092 /*
1093 * look for key in the tree. path is filled in with nodes along the way
1094 * if key is found, we return zero and you can find the item in the leaf
1095 * level of the path (level 0)
1096 *
1097 * If the key isn't found, the path points to the slot where it should
1098 * be inserted, and 1 is returned. If there are other errors during the
1099 * search a negative error number is returned.
1100 *
1101 * if ins_len > 0, nodes and leaves will be split as we walk down the
1102 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
1103 * possible)
1104 */
1105 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
1106 *root, struct btrfs_key *key, struct btrfs_path *p, int
1107 ins_len, int cow)
1108 {
1109 struct extent_buffer *b;
1110 u64 bytenr;
1111 u64 ptr_gen;
1112 int slot;
1113 int ret;
1114 int level;
1115 int should_reada = p->reada;
1116 u8 lowest_level = 0;
1117
1118 lowest_level = p->lowest_level;
1119 WARN_ON(lowest_level && ins_len);
1120 WARN_ON(p->nodes[0] != NULL);
1121 WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
1122 again:
1123 b = root->node;
1124 extent_buffer_get(b);
1125 while (b) {
1126 level = btrfs_header_level(b);
1127 if (cow) {
1128 int wret;
1129 wret = btrfs_cow_block(trans, root, b,
1130 p->nodes[level + 1],
1131 p->slots[level + 1],
1132 &b);
1133 if (wret) {
1134 free_extent_buffer(b);
1135 return wret;
1136 }
1137 }
1138 BUG_ON(!cow && ins_len);
1139 if (level != btrfs_header_level(b))
1140 WARN_ON(1);
1141 level = btrfs_header_level(b);
1142 p->nodes[level] = b;
1143 ret = check_block(root, p, level);
1144 if (ret)
1145 return -1;
1146 ret = bin_search(b, key, level, &slot);
1147 if (level != 0) {
1148 if (ret && slot > 0)
1149 slot -= 1;
1150 p->slots[level] = slot;
1151 if (ins_len > 0 && btrfs_header_nritems(b) >=
1152 BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1153 int sret = split_node(trans, root, p, level);
1154 BUG_ON(sret > 0);
1155 if (sret)
1156 return sret;
1157 b = p->nodes[level];
1158 slot = p->slots[level];
1159 } else if (ins_len < 0) {
1160 int sret = balance_level(trans, root, p,
1161 level);
1162 if (sret)
1163 return sret;
1164 b = p->nodes[level];
1165 if (!b) {
1166 btrfs_release_path(NULL, p);
1167 goto again;
1168 }
1169 slot = p->slots[level];
1170 BUG_ON(btrfs_header_nritems(b) == 1);
1171 }
1172 /* this is only true while dropping a snapshot */
1173 if (level == lowest_level)
1174 break;
1175 bytenr = btrfs_node_blockptr(b, slot);
1176 ptr_gen = btrfs_node_ptr_generation(b, slot);
1177 if (should_reada)
1178 reada_for_search(root, p, level, slot,
1179 key->objectid);
1180 b = read_tree_block(root, bytenr,
1181 btrfs_level_size(root, level - 1));
1182 if (ptr_gen != btrfs_header_generation(b)) {
1183 printk("block %llu bad gen wanted %llu "
1184 "found %llu\n",
1185 (unsigned long long)b->start,
1186 (unsigned long long)ptr_gen,
1187 (unsigned long long)btrfs_header_generation(b));
1188 }
1189 } else {
1190 p->slots[level] = slot;
1191 if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1192 sizeof(struct btrfs_item) + ins_len) {
1193 int sret = split_leaf(trans, root, key,
1194 p, ins_len, ret == 0);
1195 BUG_ON(sret > 0);
1196 if (sret)
1197 return sret;
1198 }
1199 return ret;
1200 }
1201 }
1202 return 1;
1203 }
1204
1205 /*
1206 * adjust the pointers going up the tree, starting at level
1207 * making sure the right key of each node is points to 'key'.
1208 * This is used after shifting pointers to the left, so it stops
1209 * fixing up pointers when a given leaf/node is not in slot 0 of the
1210 * higher levels
1211 *
1212 * If this fails to write a tree block, it returns -1, but continues
1213 * fixing up the blocks in ram so the tree is consistent.
1214 */
1215 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1216 struct btrfs_root *root, struct btrfs_path *path,
1217 struct btrfs_disk_key *key, int level)
1218 {
1219 int i;
1220 int ret = 0;
1221 struct extent_buffer *t;
1222
1223 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1224 int tslot = path->slots[i];
1225 if (!path->nodes[i])
1226 break;
1227 t = path->nodes[i];
1228 btrfs_set_node_key(t, key, tslot);
1229 btrfs_mark_buffer_dirty(path->nodes[i]);
1230 if (tslot != 0)
1231 break;
1232 }
1233 return ret;
1234 }
1235
1236 /*
1237 * try to push data from one node into the next node left in the
1238 * tree.
1239 *
1240 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1241 * error, and > 0 if there was no room in the left hand block.
1242 */
1243 static int push_node_left(struct btrfs_trans_handle *trans,
1244 struct btrfs_root *root, struct extent_buffer *dst,
1245 struct extent_buffer *src)
1246 {
1247 int push_items = 0;
1248 int src_nritems;
1249 int dst_nritems;
1250 int ret = 0;
1251
1252 src_nritems = btrfs_header_nritems(src);
1253 dst_nritems = btrfs_header_nritems(dst);
1254 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1255 WARN_ON(btrfs_header_generation(src) != trans->transid);
1256 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1257
1258 if (push_items <= 0) {
1259 return 1;
1260 }
1261
1262 if (src_nritems < push_items)
1263 push_items = src_nritems;
1264
1265 copy_extent_buffer(dst, src,
1266 btrfs_node_key_ptr_offset(dst_nritems),
1267 btrfs_node_key_ptr_offset(0),
1268 push_items * sizeof(struct btrfs_key_ptr));
1269
1270 if (push_items < src_nritems) {
1271 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1272 btrfs_node_key_ptr_offset(push_items),
1273 (src_nritems - push_items) *
1274 sizeof(struct btrfs_key_ptr));
1275 }
1276 btrfs_set_header_nritems(src, src_nritems - push_items);
1277 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1278 btrfs_mark_buffer_dirty(src);
1279 btrfs_mark_buffer_dirty(dst);
1280 return ret;
1281 }
1282
1283 /*
1284 * try to push data from one node into the next node right in the
1285 * tree.
1286 *
1287 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1288 * error, and > 0 if there was no room in the right hand block.
1289 *
1290 * this will only push up to 1/2 the contents of the left node over
1291 */
1292 static int balance_node_right(struct btrfs_trans_handle *trans,
1293 struct btrfs_root *root,
1294 struct extent_buffer *dst,
1295 struct extent_buffer *src)
1296 {
1297 int push_items = 0;
1298 int max_push;
1299 int src_nritems;
1300 int dst_nritems;
1301 int ret = 0;
1302
1303 WARN_ON(btrfs_header_generation(src) != trans->transid);
1304 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1305
1306 src_nritems = btrfs_header_nritems(src);
1307 dst_nritems = btrfs_header_nritems(dst);
1308 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1309 if (push_items <= 0)
1310 return 1;
1311
1312 max_push = src_nritems / 2 + 1;
1313 /* don't try to empty the node */
1314 if (max_push >= src_nritems)
1315 return 1;
1316
1317 if (max_push < push_items)
1318 push_items = max_push;
1319
1320 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1321 btrfs_node_key_ptr_offset(0),
1322 (dst_nritems) *
1323 sizeof(struct btrfs_key_ptr));
1324
1325 copy_extent_buffer(dst, src,
1326 btrfs_node_key_ptr_offset(0),
1327 btrfs_node_key_ptr_offset(src_nritems - push_items),
1328 push_items * sizeof(struct btrfs_key_ptr));
1329
1330 btrfs_set_header_nritems(src, src_nritems - push_items);
1331 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1332
1333 btrfs_mark_buffer_dirty(src);
1334 btrfs_mark_buffer_dirty(dst);
1335 return ret;
1336 }
1337
1338 /*
1339 * helper function to insert a new root level in the tree.
1340 * A new node is allocated, and a single item is inserted to
1341 * point to the existing root
1342 *
1343 * returns zero on success or < 0 on failure.
1344 */
1345 static int noinline insert_new_root(struct btrfs_trans_handle *trans,
1346 struct btrfs_root *root,
1347 struct btrfs_path *path, int level)
1348 {
1349 u64 root_gen;
1350 u64 lower_gen;
1351 struct extent_buffer *lower;
1352 struct extent_buffer *c;
1353 struct btrfs_disk_key lower_key;
1354
1355 BUG_ON(path->nodes[level]);
1356 BUG_ON(path->nodes[level-1] != root->node);
1357
1358 if (root->ref_cows)
1359 root_gen = trans->transid;
1360 else
1361 root_gen = 0;
1362
1363 lower = path->nodes[level-1];
1364 if (level == 1)
1365 btrfs_item_key(lower, &lower_key, 0);
1366 else
1367 btrfs_node_key(lower, &lower_key, 0);
1368
1369 c = __btrfs_alloc_free_block(trans, root, root->nodesize,
1370 root->root_key.objectid,
1371 root_gen, lower_key.objectid, level,
1372 root->node->start, 0);
1373 if (IS_ERR(c))
1374 return PTR_ERR(c);
1375 memset_extent_buffer(c, 0, 0, root->nodesize);
1376 btrfs_set_header_nritems(c, 1);
1377 btrfs_set_header_level(c, level);
1378 btrfs_set_header_bytenr(c, c->start);
1379 btrfs_set_header_generation(c, trans->transid);
1380 btrfs_set_header_owner(c, root->root_key.objectid);
1381
1382 write_extent_buffer(c, root->fs_info->fsid,
1383 (unsigned long)btrfs_header_fsid(c),
1384 BTRFS_FSID_SIZE);
1385 btrfs_set_node_key(c, &lower_key, 0);
1386 btrfs_set_node_blockptr(c, 0, lower->start);
1387 lower_gen = btrfs_header_generation(lower);
1388 WARN_ON(lower_gen == 0);
1389
1390 btrfs_set_node_ptr_generation(c, 0, lower_gen);
1391
1392 btrfs_mark_buffer_dirty(c);
1393
1394 /* the super has an extra ref to root->node */
1395 free_extent_buffer(root->node);
1396 root->node = c;
1397 add_root_to_dirty_list(root);
1398 extent_buffer_get(c);
1399 path->nodes[level] = c;
1400 path->slots[level] = 0;
1401
1402 if (root->ref_cows && lower_gen != trans->transid) {
1403 struct btrfs_path *back_path = btrfs_alloc_path();
1404 int ret;
1405 ret = btrfs_insert_extent_backref(trans,
1406 root->fs_info->extent_root,
1407 path, lower->start,
1408 root->root_key.objectid,
1409 trans->transid, 0, 0);
1410 BUG_ON(ret);
1411 btrfs_free_path(back_path);
1412 }
1413 return 0;
1414 }
1415
1416 /*
1417 * worker function to insert a single pointer in a node.
1418 * the node should have enough room for the pointer already
1419 *
1420 * slot and level indicate where you want the key to go, and
1421 * blocknr is the block the key points to.
1422 *
1423 * returns zero on success and < 0 on any error
1424 */
1425 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1426 *root, struct btrfs_path *path, struct btrfs_disk_key
1427 *key, u64 bytenr, int slot, int level)
1428 {
1429 struct extent_buffer *lower;
1430 int nritems;
1431
1432 BUG_ON(!path->nodes[level]);
1433 lower = path->nodes[level];
1434 nritems = btrfs_header_nritems(lower);
1435 if (slot > nritems)
1436 BUG();
1437 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1438 BUG();
1439 if (slot != nritems) {
1440 memmove_extent_buffer(lower,
1441 btrfs_node_key_ptr_offset(slot + 1),
1442 btrfs_node_key_ptr_offset(slot),
1443 (nritems - slot) * sizeof(struct btrfs_key_ptr));
1444 }
1445 btrfs_set_node_key(lower, key, slot);
1446 btrfs_set_node_blockptr(lower, slot, bytenr);
1447 WARN_ON(trans->transid == 0);
1448 btrfs_set_node_ptr_generation(lower, slot, trans->transid);
1449 btrfs_set_header_nritems(lower, nritems + 1);
1450 btrfs_mark_buffer_dirty(lower);
1451 return 0;
1452 }
1453
1454 /*
1455 * split the node at the specified level in path in two.
1456 * The path is corrected to point to the appropriate node after the split
1457 *
1458 * Before splitting this tries to make some room in the node by pushing
1459 * left and right, if either one works, it returns right away.
1460 *
1461 * returns 0 on success and < 0 on failure
1462 */
1463 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1464 *root, struct btrfs_path *path, int level)
1465 {
1466 u64 root_gen;
1467 struct extent_buffer *c;
1468 struct extent_buffer *split;
1469 struct btrfs_disk_key disk_key;
1470 int mid;
1471 int ret;
1472 int wret;
1473 u32 c_nritems;
1474
1475 c = path->nodes[level];
1476 WARN_ON(btrfs_header_generation(c) != trans->transid);
1477 if (c == root->node) {
1478 /* trying to split the root, lets make a new one */
1479 ret = insert_new_root(trans, root, path, level + 1);
1480 if (ret)
1481 return ret;
1482 } else {
1483 ret = push_nodes_for_insert(trans, root, path, level);
1484 c = path->nodes[level];
1485 if (!ret && btrfs_header_nritems(c) <
1486 BTRFS_NODEPTRS_PER_BLOCK(root) - 1)
1487 return 0;
1488 if (ret < 0)
1489 return ret;
1490 }
1491
1492 c_nritems = btrfs_header_nritems(c);
1493 if (root->ref_cows)
1494 root_gen = trans->transid;
1495 else
1496 root_gen = 0;
1497
1498 btrfs_node_key(c, &disk_key, 0);
1499 split = __btrfs_alloc_free_block(trans, root, root->nodesize,
1500 root->root_key.objectid,
1501 root_gen,
1502 btrfs_disk_key_objectid(&disk_key),
1503 level, c->start, 0);
1504 if (IS_ERR(split))
1505 return PTR_ERR(split);
1506
1507 btrfs_set_header_flags(split, btrfs_header_flags(c));
1508 btrfs_set_header_level(split, btrfs_header_level(c));
1509 btrfs_set_header_bytenr(split, split->start);
1510 btrfs_set_header_generation(split, trans->transid);
1511 btrfs_set_header_owner(split, root->root_key.objectid);
1512 btrfs_set_header_flags(split, 0);
1513 write_extent_buffer(split, root->fs_info->fsid,
1514 (unsigned long)btrfs_header_fsid(split),
1515 BTRFS_FSID_SIZE);
1516
1517 mid = (c_nritems + 1) / 2;
1518
1519 copy_extent_buffer(split, c,
1520 btrfs_node_key_ptr_offset(0),
1521 btrfs_node_key_ptr_offset(mid),
1522 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1523 btrfs_set_header_nritems(split, c_nritems - mid);
1524 btrfs_set_header_nritems(c, mid);
1525 ret = 0;
1526
1527 btrfs_mark_buffer_dirty(c);
1528 btrfs_mark_buffer_dirty(split);
1529
1530 btrfs_node_key(split, &disk_key, 0);
1531 wret = insert_ptr(trans, root, path, &disk_key, split->start,
1532 path->slots[level + 1] + 1,
1533 level + 1);
1534 if (wret)
1535 ret = wret;
1536
1537 if (path->slots[level] >= mid) {
1538 path->slots[level] -= mid;
1539 free_extent_buffer(c);
1540 path->nodes[level] = split;
1541 path->slots[level + 1] += 1;
1542 } else {
1543 free_extent_buffer(split);
1544 }
1545 return ret;
1546 }
1547
1548 /*
1549 * how many bytes are required to store the items in a leaf. start
1550 * and nr indicate which items in the leaf to check. This totals up the
1551 * space used both by the item structs and the item data
1552 */
1553 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1554 {
1555 int data_len;
1556 int nritems = btrfs_header_nritems(l);
1557 int end = min(nritems, start + nr) - 1;
1558
1559 if (!nr)
1560 return 0;
1561 data_len = btrfs_item_end_nr(l, start);
1562 data_len = data_len - btrfs_item_offset_nr(l, end);
1563 data_len += sizeof(struct btrfs_item) * nr;
1564 WARN_ON(data_len < 0);
1565 return data_len;
1566 }
1567
1568 /*
1569 * The space between the end of the leaf items and
1570 * the start of the leaf data. IOW, how much room
1571 * the leaf has left for both items and data
1572 */
1573 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1574 {
1575 int nritems = btrfs_header_nritems(leaf);
1576 int ret;
1577 ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1578 if (ret < 0) {
1579 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1580 ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
1581 leaf_space_used(leaf, 0, nritems), nritems);
1582 }
1583 return ret;
1584 }
1585
1586 /*
1587 * push some data in the path leaf to the right, trying to free up at
1588 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1589 *
1590 * returns 1 if the push failed because the other node didn't have enough
1591 * room, 0 if everything worked out and < 0 if there were major errors.
1592 */
1593 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1594 *root, struct btrfs_path *path, int data_size,
1595 int empty)
1596 {
1597 struct extent_buffer *left = path->nodes[0];
1598 struct extent_buffer *right;
1599 struct extent_buffer *upper;
1600 struct btrfs_disk_key disk_key;
1601 int slot;
1602 u32 i;
1603 int free_space;
1604 int push_space = 0;
1605 int push_items = 0;
1606 struct btrfs_item *item;
1607 u32 left_nritems;
1608 u32 nr;
1609 u32 right_nritems;
1610 u32 data_end;
1611 u32 this_item_size;
1612 int ret;
1613
1614 slot = path->slots[1];
1615 if (!path->nodes[1]) {
1616 return 1;
1617 }
1618 upper = path->nodes[1];
1619 if (slot >= btrfs_header_nritems(upper) - 1)
1620 return 1;
1621
1622 right = read_tree_block(root, btrfs_node_blockptr(upper, slot + 1),
1623 root->leafsize);
1624 free_space = btrfs_leaf_free_space(root, right);
1625 if (free_space < data_size + sizeof(struct btrfs_item)) {
1626 free_extent_buffer(right);
1627 return 1;
1628 }
1629
1630 /* cow and double check */
1631 ret = btrfs_cow_block(trans, root, right, upper,
1632 slot + 1, &right);
1633 if (ret) {
1634 free_extent_buffer(right);
1635 return 1;
1636 }
1637 free_space = btrfs_leaf_free_space(root, right);
1638 if (free_space < data_size + sizeof(struct btrfs_item)) {
1639 free_extent_buffer(right);
1640 return 1;
1641 }
1642
1643 left_nritems = btrfs_header_nritems(left);
1644 if (left_nritems == 0) {
1645 free_extent_buffer(right);
1646 return 1;
1647 }
1648
1649 if (empty)
1650 nr = 0;
1651 else
1652 nr = 1;
1653
1654 i = left_nritems - 1;
1655 while (i >= nr) {
1656 item = btrfs_item_nr(left, i);
1657
1658 if (path->slots[0] == i)
1659 push_space += data_size + sizeof(*item);
1660
1661 if (!left->map_token) {
1662 map_extent_buffer(left, (unsigned long)item,
1663 sizeof(struct btrfs_item),
1664 &left->map_token, &left->kaddr,
1665 &left->map_start, &left->map_len,
1666 KM_USER1);
1667 }
1668
1669 this_item_size = btrfs_item_size(left, item);
1670 if (this_item_size + sizeof(*item) + push_space > free_space)
1671 break;
1672 push_items++;
1673 push_space += this_item_size + sizeof(*item);
1674 if (i == 0)
1675 break;
1676 i--;
1677 }
1678 if (left->map_token) {
1679 unmap_extent_buffer(left, left->map_token, KM_USER1);
1680 left->map_token = NULL;
1681 }
1682
1683 if (push_items == 0) {
1684 free_extent_buffer(right);
1685 return 1;
1686 }
1687
1688 if (!empty && push_items == left_nritems)
1689 WARN_ON(1);
1690
1691 /* push left to right */
1692 right_nritems = btrfs_header_nritems(right);
1693
1694 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1695 push_space -= leaf_data_end(root, left);
1696
1697 /* make room in the right data area */
1698 data_end = leaf_data_end(root, right);
1699 memmove_extent_buffer(right,
1700 btrfs_leaf_data(right) + data_end - push_space,
1701 btrfs_leaf_data(right) + data_end,
1702 BTRFS_LEAF_DATA_SIZE(root) - data_end);
1703
1704 /* copy from the left data area */
1705 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1706 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1707 btrfs_leaf_data(left) + leaf_data_end(root, left),
1708 push_space);
1709
1710 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1711 btrfs_item_nr_offset(0),
1712 right_nritems * sizeof(struct btrfs_item));
1713
1714 /* copy the items from left to right */
1715 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1716 btrfs_item_nr_offset(left_nritems - push_items),
1717 push_items * sizeof(struct btrfs_item));
1718
1719 /* update the item pointers */
1720 right_nritems += push_items;
1721 btrfs_set_header_nritems(right, right_nritems);
1722 push_space = BTRFS_LEAF_DATA_SIZE(root);
1723 for (i = 0; i < right_nritems; i++) {
1724 item = btrfs_item_nr(right, i);
1725 if (!right->map_token) {
1726 map_extent_buffer(right, (unsigned long)item,
1727 sizeof(struct btrfs_item),
1728 &right->map_token, &right->kaddr,
1729 &right->map_start, &right->map_len,
1730 KM_USER1);
1731 }
1732 push_space -= btrfs_item_size(right, item);
1733 btrfs_set_item_offset(right, item, push_space);
1734 }
1735
1736 if (right->map_token) {
1737 unmap_extent_buffer(right, right->map_token, KM_USER1);
1738 right->map_token = NULL;
1739 }
1740 left_nritems -= push_items;
1741 btrfs_set_header_nritems(left, left_nritems);
1742
1743 if (left_nritems)
1744 btrfs_mark_buffer_dirty(left);
1745 btrfs_mark_buffer_dirty(right);
1746
1747 btrfs_item_key(right, &disk_key, 0);
1748 btrfs_set_node_key(upper, &disk_key, slot + 1);
1749 btrfs_mark_buffer_dirty(upper);
1750
1751 /* then fixup the leaf pointer in the path */
1752 if (path->slots[0] >= left_nritems) {
1753 path->slots[0] -= left_nritems;
1754 free_extent_buffer(path->nodes[0]);
1755 path->nodes[0] = right;
1756 path->slots[1] += 1;
1757 } else {
1758 free_extent_buffer(right);
1759 }
1760 return 0;
1761 }
1762 /*
1763 * push some data in the path leaf to the left, trying to free up at
1764 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1765 */
1766 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1767 *root, struct btrfs_path *path, int data_size,
1768 int empty)
1769 {
1770 struct btrfs_disk_key disk_key;
1771 struct extent_buffer *right = path->nodes[0];
1772 struct extent_buffer *left;
1773 int slot;
1774 int i;
1775 int free_space;
1776 int push_space = 0;
1777 int push_items = 0;
1778 struct btrfs_item *item;
1779 u32 old_left_nritems;
1780 u32 right_nritems;
1781 u32 nr;
1782 int ret = 0;
1783 int wret;
1784 u32 this_item_size;
1785 u32 old_left_item_size;
1786
1787 slot = path->slots[1];
1788 if (slot == 0)
1789 return 1;
1790 if (!path->nodes[1])
1791 return 1;
1792
1793 right_nritems = btrfs_header_nritems(right);
1794 if (right_nritems == 0) {
1795 return 1;
1796 }
1797
1798 left = read_tree_block(root, btrfs_node_blockptr(path->nodes[1],
1799 slot - 1), root->leafsize);
1800 free_space = btrfs_leaf_free_space(root, left);
1801 if (free_space < data_size + sizeof(struct btrfs_item)) {
1802 free_extent_buffer(left);
1803 return 1;
1804 }
1805
1806 /* cow and double check */
1807 ret = btrfs_cow_block(trans, root, left,
1808 path->nodes[1], slot - 1, &left);
1809 if (ret) {
1810 /* we hit -ENOSPC, but it isn't fatal here */
1811 free_extent_buffer(left);
1812 return 1;
1813 }
1814
1815 free_space = btrfs_leaf_free_space(root, left);
1816 if (free_space < data_size + sizeof(struct btrfs_item)) {
1817 free_extent_buffer(left);
1818 return 1;
1819 }
1820
1821 if (empty)
1822 nr = right_nritems;
1823 else
1824 nr = right_nritems - 1;
1825
1826 for (i = 0; i < nr; i++) {
1827 item = btrfs_item_nr(right, i);
1828 if (!right->map_token) {
1829 map_extent_buffer(right, (unsigned long)item,
1830 sizeof(struct btrfs_item),
1831 &right->map_token, &right->kaddr,
1832 &right->map_start, &right->map_len,
1833 KM_USER1);
1834 }
1835
1836 if (path->slots[0] == i)
1837 push_space += data_size + sizeof(*item);
1838
1839 this_item_size = btrfs_item_size(right, item);
1840 if (this_item_size + sizeof(*item) + push_space > free_space)
1841 break;
1842
1843 push_items++;
1844 push_space += this_item_size + sizeof(*item);
1845 }
1846
1847 if (right->map_token) {
1848 unmap_extent_buffer(right, right->map_token, KM_USER1);
1849 right->map_token = NULL;
1850 }
1851
1852 if (push_items == 0) {
1853 free_extent_buffer(left);
1854 return 1;
1855 }
1856 if (!empty && push_items == btrfs_header_nritems(right))
1857 WARN_ON(1);
1858
1859 /* push data from right to left */
1860 copy_extent_buffer(left, right,
1861 btrfs_item_nr_offset(btrfs_header_nritems(left)),
1862 btrfs_item_nr_offset(0),
1863 push_items * sizeof(struct btrfs_item));
1864
1865 push_space = BTRFS_LEAF_DATA_SIZE(root) -
1866 btrfs_item_offset_nr(right, push_items -1);
1867
1868 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
1869 leaf_data_end(root, left) - push_space,
1870 btrfs_leaf_data(right) +
1871 btrfs_item_offset_nr(right, push_items - 1),
1872 push_space);
1873 old_left_nritems = btrfs_header_nritems(left);
1874 BUG_ON(old_left_nritems < 0);
1875
1876 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
1877 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1878 u32 ioff;
1879
1880 item = btrfs_item_nr(left, i);
1881 if (!left->map_token) {
1882 map_extent_buffer(left, (unsigned long)item,
1883 sizeof(struct btrfs_item),
1884 &left->map_token, &left->kaddr,
1885 &left->map_start, &left->map_len,
1886 KM_USER1);
1887 }
1888
1889 ioff = btrfs_item_offset(left, item);
1890 btrfs_set_item_offset(left, item,
1891 ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
1892 }
1893 btrfs_set_header_nritems(left, old_left_nritems + push_items);
1894 if (left->map_token) {
1895 unmap_extent_buffer(left, left->map_token, KM_USER1);
1896 left->map_token = NULL;
1897 }
1898
1899 /* fixup right node */
1900 if (push_items > right_nritems) {
1901 printk("push items %d nr %u\n", push_items, right_nritems);
1902 WARN_ON(1);
1903 }
1904
1905 if (push_items < right_nritems) {
1906 push_space = btrfs_item_offset_nr(right, push_items - 1) -
1907 leaf_data_end(root, right);
1908 memmove_extent_buffer(right, btrfs_leaf_data(right) +
1909 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1910 btrfs_leaf_data(right) +
1911 leaf_data_end(root, right), push_space);
1912
1913 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
1914 btrfs_item_nr_offset(push_items),
1915 (btrfs_header_nritems(right) - push_items) *
1916 sizeof(struct btrfs_item));
1917 }
1918 right_nritems -= push_items;
1919 btrfs_set_header_nritems(right, right_nritems);
1920 push_space = BTRFS_LEAF_DATA_SIZE(root);
1921 for (i = 0; i < right_nritems; i++) {
1922 item = btrfs_item_nr(right, i);
1923
1924 if (!right->map_token) {
1925 map_extent_buffer(right, (unsigned long)item,
1926 sizeof(struct btrfs_item),
1927 &right->map_token, &right->kaddr,
1928 &right->map_start, &right->map_len,
1929 KM_USER1);
1930 }
1931
1932 push_space = push_space - btrfs_item_size(right, item);
1933 btrfs_set_item_offset(right, item, push_space);
1934 }
1935 if (right->map_token) {
1936 unmap_extent_buffer(right, right->map_token, KM_USER1);
1937 right->map_token = NULL;
1938 }
1939
1940 btrfs_mark_buffer_dirty(left);
1941 if (right_nritems)
1942 btrfs_mark_buffer_dirty(right);
1943
1944 btrfs_item_key(right, &disk_key, 0);
1945 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1946 if (wret)
1947 ret = wret;
1948
1949 /* then fixup the leaf pointer in the path */
1950 if (path->slots[0] < push_items) {
1951 path->slots[0] += old_left_nritems;
1952 free_extent_buffer(path->nodes[0]);
1953 path->nodes[0] = left;
1954 path->slots[1] -= 1;
1955 } else {
1956 free_extent_buffer(left);
1957 path->slots[0] -= push_items;
1958 }
1959 BUG_ON(path->slots[0] < 0);
1960 return ret;
1961 }
1962
1963 /*
1964 * split the path's leaf in two, making sure there is at least data_size
1965 * available for the resulting leaf level of the path.
1966 *
1967 * returns 0 if all went well and < 0 on failure.
1968 */
1969 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1970 *root, struct btrfs_key *ins_key,
1971 struct btrfs_path *path, int data_size, int extend)
1972 {
1973 u64 root_gen;
1974 struct extent_buffer *l;
1975 u32 nritems;
1976 int mid;
1977 int slot;
1978 struct extent_buffer *right;
1979 int space_needed = data_size + sizeof(struct btrfs_item);
1980 int data_copy_size;
1981 int rt_data_off;
1982 int i;
1983 int ret = 0;
1984 int wret;
1985 int double_split;
1986 int num_doubles = 0;
1987 struct btrfs_disk_key disk_key;
1988
1989 if (extend)
1990 space_needed = data_size;
1991
1992 if (root->ref_cows)
1993 root_gen = trans->transid;
1994 else
1995 root_gen = 0;
1996
1997 /* first try to make some room by pushing left and right */
1998 if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
1999 wret = push_leaf_right(trans, root, path, data_size, 0);
2000 if (wret < 0) {
2001 return wret;
2002 }
2003 if (wret) {
2004 wret = push_leaf_left(trans, root, path, data_size, 0);
2005 if (wret < 0)
2006 return wret;
2007 }
2008 l = path->nodes[0];
2009
2010 /* did the pushes work? */
2011 if (btrfs_leaf_free_space(root, l) >= space_needed)
2012 return 0;
2013 }
2014
2015 if (!path->nodes[1]) {
2016 ret = insert_new_root(trans, root, path, 1);
2017 if (ret)
2018 return ret;
2019 }
2020 again:
2021 double_split = 0;
2022 l = path->nodes[0];
2023 slot = path->slots[0];
2024 nritems = btrfs_header_nritems(l);
2025 mid = (nritems + 1)/ 2;
2026
2027 btrfs_item_key(l, &disk_key, 0);
2028
2029 right = __btrfs_alloc_free_block(trans, root, root->leafsize,
2030 root->root_key.objectid,
2031 root_gen, disk_key.objectid, 0,
2032 l->start, 0);
2033 if (IS_ERR(right)) {
2034 BUG_ON(1);
2035 return PTR_ERR(right);
2036 }
2037
2038 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
2039 btrfs_set_header_bytenr(right, right->start);
2040 btrfs_set_header_generation(right, trans->transid);
2041 btrfs_set_header_owner(right, root->root_key.objectid);
2042 btrfs_set_header_level(right, 0);
2043 write_extent_buffer(right, root->fs_info->fsid,
2044 (unsigned long)btrfs_header_fsid(right),
2045 BTRFS_FSID_SIZE);
2046 if (mid <= slot) {
2047 if (nritems == 1 ||
2048 leaf_space_used(l, mid, nritems - mid) + space_needed >
2049 BTRFS_LEAF_DATA_SIZE(root)) {
2050 if (slot >= nritems) {
2051 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2052 btrfs_set_header_nritems(right, 0);
2053 wret = insert_ptr(trans, root, path,
2054 &disk_key, right->start,
2055 path->slots[1] + 1, 1);
2056 if (wret)
2057 ret = wret;
2058 free_extent_buffer(path->nodes[0]);
2059 path->nodes[0] = right;
2060 path->slots[0] = 0;
2061 path->slots[1] += 1;
2062 btrfs_mark_buffer_dirty(right);
2063 return ret;
2064 }
2065 mid = slot;
2066 if (mid != nritems &&
2067 leaf_space_used(l, mid, nritems - mid) +
2068 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2069 double_split = 1;
2070 }
2071 }
2072 } else {
2073 if (leaf_space_used(l, 0, mid + 1) + space_needed >
2074 BTRFS_LEAF_DATA_SIZE(root)) {
2075 if (!extend && slot == 0) {
2076 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2077 btrfs_set_header_nritems(right, 0);
2078 wret = insert_ptr(trans, root, path,
2079 &disk_key,
2080 right->start,
2081 path->slots[1], 1);
2082 if (wret)
2083 ret = wret;
2084 free_extent_buffer(path->nodes[0]);
2085 path->nodes[0] = right;
2086 path->slots[0] = 0;
2087 if (path->slots[1] == 0) {
2088 wret = fixup_low_keys(trans, root,
2089 path, &disk_key, 1);
2090 if (wret)
2091 ret = wret;
2092 }
2093 btrfs_mark_buffer_dirty(right);
2094 return ret;
2095 } else if (extend && slot == 0) {
2096 mid = 1;
2097 } else {
2098 mid = slot;
2099 if (mid != nritems &&
2100 leaf_space_used(l, mid, nritems - mid) +
2101 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2102 double_split = 1;
2103 }
2104 }
2105 }
2106 }
2107 nritems = nritems - mid;
2108 btrfs_set_header_nritems(right, nritems);
2109 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
2110
2111 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
2112 btrfs_item_nr_offset(mid),
2113 nritems * sizeof(struct btrfs_item));
2114
2115 copy_extent_buffer(right, l,
2116 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
2117 data_copy_size, btrfs_leaf_data(l) +
2118 leaf_data_end(root, l), data_copy_size);
2119
2120 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
2121 btrfs_item_end_nr(l, mid);
2122
2123 for (i = 0; i < nritems; i++) {
2124 struct btrfs_item *item = btrfs_item_nr(right, i);
2125 u32 ioff;
2126
2127 if (!right->map_token) {
2128 map_extent_buffer(right, (unsigned long)item,
2129 sizeof(struct btrfs_item),
2130 &right->map_token, &right->kaddr,
2131 &right->map_start, &right->map_len,
2132 KM_USER1);
2133 }
2134
2135 ioff = btrfs_item_offset(right, item);
2136 btrfs_set_item_offset(right, item, ioff + rt_data_off);
2137 }
2138
2139 if (right->map_token) {
2140 unmap_extent_buffer(right, right->map_token, KM_USER1);
2141 right->map_token = NULL;
2142 }
2143
2144 btrfs_set_header_nritems(l, mid);
2145 ret = 0;
2146 btrfs_item_key(right, &disk_key, 0);
2147 wret = insert_ptr(trans, root, path, &disk_key, right->start,
2148 path->slots[1] + 1, 1);
2149 if (wret)
2150 ret = wret;
2151
2152 btrfs_mark_buffer_dirty(right);
2153 btrfs_mark_buffer_dirty(l);
2154 BUG_ON(path->slots[0] != slot);
2155
2156 if (mid <= slot) {
2157 free_extent_buffer(path->nodes[0]);
2158 path->nodes[0] = right;
2159 path->slots[0] -= mid;
2160 path->slots[1] += 1;
2161 } else
2162 free_extent_buffer(right);
2163
2164 BUG_ON(path->slots[0] < 0);
2165
2166 if (double_split) {
2167 BUG_ON(num_doubles != 0);
2168 num_doubles++;
2169 goto again;
2170 }
2171 return ret;
2172 }
2173
2174 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
2175 struct btrfs_root *root,
2176 struct btrfs_path *path,
2177 u32 new_size, int from_end)
2178 {
2179 int ret = 0;
2180 int slot;
2181 int slot_orig;
2182 struct extent_buffer *leaf;
2183 struct btrfs_item *item;
2184 u32 nritems;
2185 unsigned int data_end;
2186 unsigned int old_data_start;
2187 unsigned int old_size;
2188 unsigned int size_diff;
2189 int i;
2190
2191 slot_orig = path->slots[0];
2192 leaf = path->nodes[0];
2193 slot = path->slots[0];
2194
2195 old_size = btrfs_item_size_nr(leaf, slot);
2196 if (old_size == new_size)
2197 return 0;
2198
2199 nritems = btrfs_header_nritems(leaf);
2200 data_end = leaf_data_end(root, leaf);
2201
2202 old_data_start = btrfs_item_offset_nr(leaf, slot);
2203
2204 size_diff = old_size - new_size;
2205
2206 BUG_ON(slot < 0);
2207 BUG_ON(slot >= nritems);
2208
2209 /*
2210 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2211 */
2212 /* first correct the data pointers */
2213 for (i = slot; i < nritems; i++) {
2214 u32 ioff;
2215 item = btrfs_item_nr(leaf, i);
2216
2217 if (!leaf->map_token) {
2218 map_extent_buffer(leaf, (unsigned long)item,
2219 sizeof(struct btrfs_item),
2220 &leaf->map_token, &leaf->kaddr,
2221 &leaf->map_start, &leaf->map_len,
2222 KM_USER1);
2223 }
2224
2225 ioff = btrfs_item_offset(leaf, item);
2226 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2227 }
2228
2229 if (leaf->map_token) {
2230 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2231 leaf->map_token = NULL;
2232 }
2233
2234 /* shift the data */
2235 if (from_end) {
2236 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2237 data_end + size_diff, btrfs_leaf_data(leaf) +
2238 data_end, old_data_start + new_size - data_end);
2239 } else {
2240 struct btrfs_disk_key disk_key;
2241 u64 offset;
2242
2243 btrfs_item_key(leaf, &disk_key, slot);
2244
2245 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2246 unsigned long ptr;
2247 struct btrfs_file_extent_item *fi;
2248
2249 fi = btrfs_item_ptr(leaf, slot,
2250 struct btrfs_file_extent_item);
2251 fi = (struct btrfs_file_extent_item *)(
2252 (unsigned long)fi - size_diff);
2253
2254 if (btrfs_file_extent_type(leaf, fi) ==
2255 BTRFS_FILE_EXTENT_INLINE) {
2256 ptr = btrfs_item_ptr_offset(leaf, slot);
2257 memmove_extent_buffer(leaf, ptr,
2258 (unsigned long)fi,
2259 offsetof(struct btrfs_file_extent_item,
2260 disk_bytenr));
2261 }
2262 }
2263
2264 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2265 data_end + size_diff, btrfs_leaf_data(leaf) +
2266 data_end, old_data_start - data_end);
2267
2268 offset = btrfs_disk_key_offset(&disk_key);
2269 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2270 btrfs_set_item_key(leaf, &disk_key, slot);
2271 if (slot == 0)
2272 fixup_low_keys(trans, root, path, &disk_key, 1);
2273 }
2274
2275 item = btrfs_item_nr(leaf, slot);
2276 btrfs_set_item_size(leaf, item, new_size);
2277 btrfs_mark_buffer_dirty(leaf);
2278
2279 ret = 0;
2280 if (btrfs_leaf_free_space(root, leaf) < 0) {
2281 btrfs_print_leaf(root, leaf);
2282 BUG();
2283 }
2284 return ret;
2285 }
2286
2287 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2288 struct btrfs_root *root, struct btrfs_path *path,
2289 u32 data_size)
2290 {
2291 int ret = 0;
2292 int slot;
2293 int slot_orig;
2294 struct extent_buffer *leaf;
2295 struct btrfs_item *item;
2296 u32 nritems;
2297 unsigned int data_end;
2298 unsigned int old_data;
2299 unsigned int old_size;
2300 int i;
2301
2302 slot_orig = path->slots[0];
2303 leaf = path->nodes[0];
2304
2305 nritems = btrfs_header_nritems(leaf);
2306 data_end = leaf_data_end(root, leaf);
2307
2308 if (btrfs_leaf_free_space(root, leaf) < data_size) {
2309 btrfs_print_leaf(root, leaf);
2310 BUG();
2311 }
2312 slot = path->slots[0];
2313 old_data = btrfs_item_end_nr(leaf, slot);
2314
2315 BUG_ON(slot < 0);
2316 if (slot >= nritems) {
2317 btrfs_print_leaf(root, leaf);
2318 printk("slot %d too large, nritems %d\n", slot, nritems);
2319 BUG_ON(1);
2320 }
2321
2322 /*
2323 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2324 */
2325 /* first correct the data pointers */
2326 for (i = slot; i < nritems; i++) {
2327 u32 ioff;
2328 item = btrfs_item_nr(leaf, i);
2329
2330 if (!leaf->map_token) {
2331 map_extent_buffer(leaf, (unsigned long)item,
2332 sizeof(struct btrfs_item),
2333 &leaf->map_token, &leaf->kaddr,
2334 &leaf->map_start, &leaf->map_len,
2335 KM_USER1);
2336 }
2337 ioff = btrfs_item_offset(leaf, item);
2338 btrfs_set_item_offset(leaf, item, ioff - data_size);
2339 }
2340
2341 if (leaf->map_token) {
2342 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2343 leaf->map_token = NULL;
2344 }
2345
2346 /* shift the data */
2347 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2348 data_end - data_size, btrfs_leaf_data(leaf) +
2349 data_end, old_data - data_end);
2350
2351 data_end = old_data;
2352 old_size = btrfs_item_size_nr(leaf, slot);
2353 item = btrfs_item_nr(leaf, slot);
2354 btrfs_set_item_size(leaf, item, old_size + data_size);
2355 btrfs_mark_buffer_dirty(leaf);
2356
2357 ret = 0;
2358 if (btrfs_leaf_free_space(root, leaf) < 0) {
2359 btrfs_print_leaf(root, leaf);
2360 BUG();
2361 }
2362 return ret;
2363 }
2364
2365 /*
2366 * Given a key and some data, insert an item into the tree.
2367 * This does all the path init required, making room in the tree if needed.
2368 */
2369 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
2370 struct btrfs_root *root,
2371 struct btrfs_path *path,
2372 struct btrfs_key *cpu_key, u32 *data_size,
2373 int nr)
2374 {
2375 struct extent_buffer *leaf;
2376 struct btrfs_item *item;
2377 int ret = 0;
2378 int slot;
2379 int slot_orig;
2380 int i;
2381 u32 nritems;
2382 u32 total_size = 0;
2383 u32 total_data = 0;
2384 unsigned int data_end;
2385 struct btrfs_disk_key disk_key;
2386
2387 for (i = 0; i < nr; i++) {
2388 total_data += data_size[i];
2389 }
2390
2391 /* create a root if there isn't one */
2392 if (!root->node)
2393 BUG();
2394
2395 total_size = total_data + (nr - 1) * sizeof(struct btrfs_item);
2396 ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
2397 if (ret == 0) {
2398 return -EEXIST;
2399 }
2400 if (ret < 0)
2401 goto out;
2402
2403 slot_orig = path->slots[0];
2404 leaf = path->nodes[0];
2405
2406 nritems = btrfs_header_nritems(leaf);
2407 data_end = leaf_data_end(root, leaf);
2408
2409 if (btrfs_leaf_free_space(root, leaf) <
2410 sizeof(struct btrfs_item) + total_size) {
2411 btrfs_print_leaf(root, leaf);
2412 printk("not enough freespace need %u have %d\n",
2413 total_size, btrfs_leaf_free_space(root, leaf));
2414 BUG();
2415 }
2416
2417 slot = path->slots[0];
2418 BUG_ON(slot < 0);
2419
2420 if (slot != nritems) {
2421 int i;
2422 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2423
2424 if (old_data < data_end) {
2425 btrfs_print_leaf(root, leaf);
2426 printk("slot %d old_data %d data_end %d\n",
2427 slot, old_data, data_end);
2428 BUG_ON(1);
2429 }
2430 /*
2431 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2432 */
2433 /* first correct the data pointers */
2434 WARN_ON(leaf->map_token);
2435 for (i = slot; i < nritems; i++) {
2436 u32 ioff;
2437
2438 item = btrfs_item_nr(leaf, i);
2439 if (!leaf->map_token) {
2440 map_extent_buffer(leaf, (unsigned long)item,
2441 sizeof(struct btrfs_item),
2442 &leaf->map_token, &leaf->kaddr,
2443 &leaf->map_start, &leaf->map_len,
2444 KM_USER1);
2445 }
2446
2447 ioff = btrfs_item_offset(leaf, item);
2448 btrfs_set_item_offset(leaf, item, ioff - total_data);
2449 }
2450 if (leaf->map_token) {
2451 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2452 leaf->map_token = NULL;
2453 }
2454
2455 /* shift the items */
2456 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
2457 btrfs_item_nr_offset(slot),
2458 (nritems - slot) * sizeof(struct btrfs_item));
2459
2460 /* shift the data */
2461 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2462 data_end - total_data, btrfs_leaf_data(leaf) +
2463 data_end, old_data - data_end);
2464 data_end = old_data;
2465 }
2466
2467 /* setup the item for the new data */
2468 for (i = 0; i < nr; i++) {
2469 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
2470 btrfs_set_item_key(leaf, &disk_key, slot + i);
2471 item = btrfs_item_nr(leaf, slot + i);
2472 btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
2473 data_end -= data_size[i];
2474 btrfs_set_item_size(leaf, item, data_size[i]);
2475 }
2476 btrfs_set_header_nritems(leaf, nritems + nr);
2477 btrfs_mark_buffer_dirty(leaf);
2478
2479 ret = 0;
2480 if (slot == 0) {
2481 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2482 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2483 }
2484
2485 if (btrfs_leaf_free_space(root, leaf) < 0) {
2486 btrfs_print_leaf(root, leaf);
2487 BUG();
2488 }
2489
2490 out:
2491 return ret;
2492 }
2493
2494 /*
2495 * Given a key and some data, insert an item into the tree.
2496 * This does all the path init required, making room in the tree if needed.
2497 */
2498 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2499 *root, struct btrfs_key *cpu_key, void *data, u32
2500 data_size)
2501 {
2502 int ret = 0;
2503 struct btrfs_path *path;
2504 struct extent_buffer *leaf;
2505 unsigned long ptr;
2506
2507 path = btrfs_alloc_path();
2508 BUG_ON(!path);
2509 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2510 if (!ret) {
2511 leaf = path->nodes[0];
2512 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2513 write_extent_buffer(leaf, data, ptr, data_size);
2514 btrfs_mark_buffer_dirty(leaf);
2515 }
2516 btrfs_free_path(path);
2517 return ret;
2518 }
2519
2520 /*
2521 * delete the pointer from a given node.
2522 *
2523 * If the delete empties a node, the node is removed from the tree,
2524 * continuing all the way the root if required. The root is converted into
2525 * a leaf if all the nodes are emptied.
2526 */
2527 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2528 struct btrfs_path *path, int level, int slot)
2529 {
2530 struct extent_buffer *parent = path->nodes[level];
2531 u32 nritems;
2532 int ret = 0;
2533 int wret;
2534
2535 nritems = btrfs_header_nritems(parent);
2536 if (slot != nritems -1) {
2537 memmove_extent_buffer(parent,
2538 btrfs_node_key_ptr_offset(slot),
2539 btrfs_node_key_ptr_offset(slot + 1),
2540 sizeof(struct btrfs_key_ptr) *
2541 (nritems - slot - 1));
2542 }
2543 nritems--;
2544 btrfs_set_header_nritems(parent, nritems);
2545 if (nritems == 0 && parent == root->node) {
2546 BUG_ON(btrfs_header_level(root->node) != 1);
2547 /* just turn the root into a leaf and break */
2548 btrfs_set_header_level(root->node, 0);
2549 } else if (slot == 0) {
2550 struct btrfs_disk_key disk_key;
2551
2552 btrfs_node_key(parent, &disk_key, 0);
2553 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2554 if (wret)
2555 ret = wret;
2556 }
2557 btrfs_mark_buffer_dirty(parent);
2558 return ret;
2559 }
2560
2561 /*
2562 * delete the item at the leaf level in path. If that empties
2563 * the leaf, remove it from the tree
2564 */
2565 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2566 struct btrfs_path *path, int slot, int nr)
2567 {
2568 struct extent_buffer *leaf;
2569 struct btrfs_item *item;
2570 int last_off;
2571 int dsize = 0;
2572 int ret = 0;
2573 int wret;
2574 int i;
2575 u32 nritems;
2576
2577 leaf = path->nodes[0];
2578 last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
2579
2580 for (i = 0; i < nr; i++)
2581 dsize += btrfs_item_size_nr(leaf, slot + i);
2582
2583 nritems = btrfs_header_nritems(leaf);
2584
2585 if (slot + nr != nritems) {
2586 int i;
2587 int data_end = leaf_data_end(root, leaf);
2588
2589 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2590 data_end + dsize,
2591 btrfs_leaf_data(leaf) + data_end,
2592 last_off - data_end);
2593
2594 for (i = slot + nr; i < nritems; i++) {
2595 u32 ioff;
2596
2597 item = btrfs_item_nr(leaf, i);
2598 if (!leaf->map_token) {
2599 map_extent_buffer(leaf, (unsigned long)item,
2600 sizeof(struct btrfs_item),
2601 &leaf->map_token, &leaf->kaddr,
2602 &leaf->map_start, &leaf->map_len,
2603 KM_USER1);
2604 }
2605 ioff = btrfs_item_offset(leaf, item);
2606 btrfs_set_item_offset(leaf, item, ioff + dsize);
2607 }
2608
2609 if (leaf->map_token) {
2610 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2611 leaf->map_token = NULL;
2612 }
2613
2614 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2615 btrfs_item_nr_offset(slot + nr),
2616 sizeof(struct btrfs_item) *
2617 (nritems - slot - nr));
2618 }
2619 btrfs_set_header_nritems(leaf, nritems - nr);
2620 nritems -= nr;
2621
2622 /* delete the leaf if we've emptied it */
2623 if (nritems == 0) {
2624 if (leaf == root->node) {
2625 btrfs_set_header_level(leaf, 0);
2626 } else {
2627 u64 root_gen = btrfs_header_generation(path->nodes[1]);
2628 clean_tree_block(trans, root, leaf);
2629 wait_on_tree_block_writeback(root, leaf);
2630 wret = del_ptr(trans, root, path, 1, path->slots[1]);
2631 if (wret)
2632 ret = wret;
2633 wret = btrfs_free_extent(trans, root,
2634 leaf->start, leaf->len,
2635 btrfs_header_owner(path->nodes[1]),
2636 root_gen, 0, 0, 1);
2637 if (wret)
2638 ret = wret;
2639 }
2640 } else {
2641 int used = leaf_space_used(leaf, 0, nritems);
2642 if (slot == 0) {
2643 struct btrfs_disk_key disk_key;
2644
2645 btrfs_item_key(leaf, &disk_key, 0);
2646 wret = fixup_low_keys(trans, root, path,
2647 &disk_key, 1);
2648 if (wret)
2649 ret = wret;
2650 }
2651
2652 /* delete the leaf if it is mostly empty */
2653 if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
2654 /* push_leaf_left fixes the path.
2655 * make sure the path still points to our leaf
2656 * for possible call to del_ptr below
2657 */
2658 slot = path->slots[1];
2659 extent_buffer_get(leaf);
2660
2661 wret = push_leaf_left(trans, root, path, 1, 1);
2662 if (wret < 0 && wret != -ENOSPC)
2663 ret = wret;
2664
2665 if (path->nodes[0] == leaf &&
2666 btrfs_header_nritems(leaf)) {
2667 wret = push_leaf_right(trans, root, path, 1, 1);
2668 if (wret < 0 && wret != -ENOSPC)
2669 ret = wret;
2670 }
2671
2672 if (btrfs_header_nritems(leaf) == 0) {
2673 u64 root_gen;
2674 u64 bytenr = leaf->start;
2675 u32 blocksize = leaf->len;
2676
2677 root_gen = btrfs_header_generation(
2678 path->nodes[1]);
2679
2680 clean_tree_block(trans, root, leaf);
2681 wait_on_tree_block_writeback(root, leaf);
2682
2683 wret = del_ptr(trans, root, path, 1, slot);
2684 if (wret)
2685 ret = wret;
2686
2687 free_extent_buffer(leaf);
2688 wret = btrfs_free_extent(trans, root, bytenr,
2689 blocksize,
2690 btrfs_header_owner(path->nodes[1]),
2691 root_gen, 0, 0, 1);
2692 if (wret)
2693 ret = wret;
2694 } else {
2695 btrfs_mark_buffer_dirty(leaf);
2696 free_extent_buffer(leaf);
2697 }
2698 } else {
2699 btrfs_mark_buffer_dirty(leaf);
2700 }
2701 }
2702 return ret;
2703 }
2704
2705 /*
2706 * walk up the tree as far as required to find the previous leaf.
2707 * returns 0 if it found something or 1 if there are no lesser leaves.
2708 * returns < 0 on io errors.
2709 */
2710 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
2711 {
2712 u64 bytenr;
2713 int slot;
2714 int level = 1;
2715 struct extent_buffer *c;
2716 struct extent_buffer *next = NULL;
2717
2718 while(level < BTRFS_MAX_LEVEL) {
2719 if (!path->nodes[level])
2720 return 1;
2721
2722 slot = path->slots[level];
2723 c = path->nodes[level];
2724 if (slot == 0) {
2725 level++;
2726 if (level == BTRFS_MAX_LEVEL)
2727 return 1;
2728 continue;
2729 }
2730 slot--;
2731
2732 bytenr = btrfs_node_blockptr(c, slot);
2733 if (next)
2734 free_extent_buffer(next);
2735
2736 next = read_tree_block(root, bytenr,
2737 btrfs_level_size(root, level - 1));
2738 break;
2739 }
2740 path->slots[level] = slot;
2741 while(1) {
2742 level--;
2743 c = path->nodes[level];
2744 free_extent_buffer(c);
2745 slot = btrfs_header_nritems(next);
2746 if (slot != 0)
2747 slot--;
2748 path->nodes[level] = next;
2749 path->slots[level] = slot;
2750 if (!level)
2751 break;
2752 next = read_tree_block(root, btrfs_node_blockptr(next, slot),
2753 btrfs_level_size(root, level - 1));
2754 }
2755 return 0;
2756 }
2757
2758 /*
2759 * walk up the tree as far as required to find the next leaf.
2760 * returns 0 if it found something or 1 if there are no greater leaves.
2761 * returns < 0 on io errors.
2762 */
2763 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2764 {
2765 int slot;
2766 int level = 1;
2767 u64 bytenr;
2768 struct extent_buffer *c;
2769 struct extent_buffer *next = NULL;
2770
2771 while(level < BTRFS_MAX_LEVEL) {
2772 if (!path->nodes[level])
2773 return 1;
2774
2775 slot = path->slots[level] + 1;
2776 c = path->nodes[level];
2777 if (slot >= btrfs_header_nritems(c)) {
2778 level++;
2779 if (level == BTRFS_MAX_LEVEL)
2780 return 1;
2781 continue;
2782 }
2783
2784 bytenr = btrfs_node_blockptr(c, slot);
2785 if (next)
2786 free_extent_buffer(next);
2787
2788 if (path->reada)
2789 reada_for_search(root, path, level, slot, 0);
2790
2791 next = read_tree_block(root, bytenr,
2792 btrfs_level_size(root, level -1));
2793 break;
2794 }
2795 path->slots[level] = slot;
2796 while(1) {
2797 level--;
2798 c = path->nodes[level];
2799 free_extent_buffer(c);
2800 path->nodes[level] = next;
2801 path->slots[level] = 0;
2802 if (!level)
2803 break;
2804 if (path->reada)
2805 reada_for_search(root, path, level, 0, 0);
2806 next = read_tree_block(root, btrfs_node_blockptr(next, 0),
2807 btrfs_level_size(root, level - 1));
2808 }
2809 return 0;
2810 }
2811
2812 int btrfs_previous_item(struct btrfs_root *root,
2813 struct btrfs_path *path, u64 min_objectid,
2814 int type)
2815 {
2816 struct btrfs_key found_key;
2817 struct extent_buffer *leaf;
2818 int ret;
2819
2820 while(1) {
2821 if (path->slots[0] == 0) {
2822 ret = btrfs_prev_leaf(root, path);
2823 if (ret != 0)
2824 return ret;
2825 } else {
2826 path->slots[0]--;
2827 }
2828 leaf = path->nodes[0];
2829 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2830 if (found_key.type == type)
2831 return 0;
2832 }
2833 return 1;
2834 }
2835
Linux kernel - Deliverables
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