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Fix mispatch of the experimental warnings
[btrfs-progs-unstable/devel.git] / ctree.c
blob0c029a8c82f054682024a96c424dc72faa501814
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 #include "ctree.h"
19 #include "disk-io.h"
20 #include "transaction.h"
21 #include "print-tree.h"
22
23 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
24 *root, struct btrfs_path *path, int level);
25 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
26 *root, struct btrfs_key *ins_key,
27 struct btrfs_path *path, int data_size, int extend);
28 static int push_node_left(struct btrfs_trans_handle *trans,
29 struct btrfs_root *root, struct extent_buffer *dst,
30 struct extent_buffer *src, int empty);
31 static int balance_node_right(struct btrfs_trans_handle *trans,
32 struct btrfs_root *root,
33 struct extent_buffer *dst_buf,
34 struct extent_buffer *src_buf);
35 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
36 struct btrfs_path *path, int level, int slot);
37
38 inline void btrfs_init_path(struct btrfs_path *p)
39 {
40 memset(p, 0, sizeof(*p));
41 }
42
43 struct btrfs_path *btrfs_alloc_path(void)
44 {
45 struct btrfs_path *path;
46 path = kmalloc(sizeof(struct btrfs_path), GFP_NOFS);
47 if (path) {
48 btrfs_init_path(path);
49 path->reada = 0;
50 }
51 return path;
52 }
53
54 void btrfs_free_path(struct btrfs_path *p)
55 {
56 btrfs_release_path(NULL, p);
57 kfree(p);
58 }
59
60 void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
61 {
62 int i;
63 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
64 if (!p->nodes[i])
65 continue;
66 free_extent_buffer(p->nodes[i]);
67 }
68 memset(p, 0, sizeof(*p));
69 }
70
71 static void add_root_to_dirty_list(struct btrfs_root *root)
72 {
73 if (root->track_dirty && list_empty(&root->dirty_list)) {
74 list_add(&root->dirty_list,
75 &root->fs_info->dirty_cowonly_roots);
76 }
77 }
78
79 int btrfs_copy_root(struct btrfs_trans_handle *trans,
80 struct btrfs_root *root,
81 struct extent_buffer *buf,
82 struct extent_buffer **cow_ret, u64 new_root_objectid)
83 {
84 struct extent_buffer *cow;
85 int ret = 0;
86 int level;
87 struct btrfs_root *new_root;
88
89 new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
90 if (!new_root)
91 return -ENOMEM;
92
93 memcpy(new_root, root, sizeof(*new_root));
94 new_root->root_key.objectid = new_root_objectid;
95
96 WARN_ON(root->ref_cows && trans->transid !=
97 root->fs_info->running_transaction->transid);
98 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
99
100 level = btrfs_header_level(buf);
101 cow = btrfs_alloc_free_block(trans, new_root, buf->len, 0,
102 new_root_objectid, trans->transid,
103 level, buf->start, 0);
104 if (IS_ERR(cow)) {
105 kfree(new_root);
106 return PTR_ERR(cow);
107 }
108
109 copy_extent_buffer(cow, buf, 0, 0, cow->len);
110 btrfs_set_header_bytenr(cow, cow->start);
111 btrfs_set_header_generation(cow, trans->transid);
112 btrfs_set_header_owner(cow, new_root_objectid);
113 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
114
115 write_extent_buffer(cow, root->fs_info->fsid,
116 (unsigned long)btrfs_header_fsid(cow),
117 BTRFS_FSID_SIZE);
118
119 WARN_ON(btrfs_header_generation(buf) > trans->transid);
120 ret = btrfs_inc_ref(trans, new_root, buf, cow, NULL);
121 kfree(new_root);
122
123 if (ret)
124 return ret;
125
126 btrfs_mark_buffer_dirty(cow);
127 *cow_ret = cow;
128 return 0;
129 }
130
131 int __btrfs_cow_block(struct btrfs_trans_handle *trans,
132 struct btrfs_root *root,
133 struct extent_buffer *buf,
134 struct extent_buffer *parent, int parent_slot,
135 struct extent_buffer **cow_ret,
136 u64 search_start, u64 empty_size)
137 {
138 u64 parent_start;
139 struct extent_buffer *cow;
140 u32 nritems;
141 int ret = 0;
142 int different_trans = 0;
143 int level;
144
145 WARN_ON(root->ref_cows && trans->transid !=
146 root->fs_info->running_transaction->transid);
147 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
148
149 if (parent)
150 parent_start = parent->start;
151 else
152 parent_start = 0;
153
154 level = btrfs_header_level(buf);
155 nritems = btrfs_header_nritems(buf);
156 cow = btrfs_alloc_free_block(trans, root, buf->len, parent_start,
157 root->root_key.objectid, trans->transid,
158 level, search_start, empty_size);
159 if (IS_ERR(cow))
160 return PTR_ERR(cow);
161
162 copy_extent_buffer(cow, buf, 0, 0, cow->len);
163 btrfs_set_header_bytenr(cow, cow->start);
164 btrfs_set_header_generation(cow, trans->transid);
165 btrfs_set_header_owner(cow, root->root_key.objectid);
166 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
167
168 write_extent_buffer(cow, root->fs_info->fsid,
169 (unsigned long)btrfs_header_fsid(cow),
170 BTRFS_FSID_SIZE);
171
172 WARN_ON(btrfs_header_generation(buf) > trans->transid);
173 if (btrfs_header_generation(buf) != trans->transid) {
174 different_trans = 1;
175 ret = btrfs_inc_ref(trans, root, buf, cow, NULL);
176 if (ret)
177 return ret;
178 } else {
179 ret = btrfs_update_ref(trans, root, buf, cow, 0, nritems);
180 if (ret)
181 return ret;
182 clean_tree_block(trans, root, buf);
183 }
184
185 if (buf == root->node) {
186 root->node = cow;
187 extent_buffer_get(cow);
188 if (buf != root->commit_root) {
189 btrfs_free_extent(trans, root, buf->start,
190 buf->len, buf->start,
191 root->root_key.objectid,
192 btrfs_header_generation(buf),
193 level, 1);
194 }
195 free_extent_buffer(buf);
196 add_root_to_dirty_list(root);
197 } else {
198 btrfs_set_node_blockptr(parent, parent_slot,
199 cow->start);
200 WARN_ON(trans->transid == 0);
201 btrfs_set_node_ptr_generation(parent, parent_slot,
202 trans->transid);
203 btrfs_mark_buffer_dirty(parent);
204 WARN_ON(btrfs_header_generation(parent) != trans->transid);
205 btrfs_free_extent(trans, root, buf->start, buf->len,
206 parent_start, btrfs_header_owner(parent),
207 btrfs_header_generation(parent), level, 1);
208 }
209 free_extent_buffer(buf);
210 btrfs_mark_buffer_dirty(cow);
211 *cow_ret = cow;
212 return 0;
213 }
214
215 int btrfs_cow_block(struct btrfs_trans_handle *trans,
216 struct btrfs_root *root, struct extent_buffer *buf,
217 struct extent_buffer *parent, int parent_slot,
218 struct extent_buffer **cow_ret)
219 {
220 u64 search_start;
221 int ret;
222 /*
223 if (trans->transaction != root->fs_info->running_transaction) {
224 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
225 root->fs_info->running_transaction->transid);
226 WARN_ON(1);
227 }
228 */
229 if (trans->transid != root->fs_info->generation) {
230 printk(KERN_CRIT "trans %llu running %llu\n",
231 (unsigned long long)trans->transid,
232 (unsigned long long)root->fs_info->generation);
233 WARN_ON(1);
234 }
235 if (btrfs_header_generation(buf) == trans->transid &&
236 !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
237 *cow_ret = buf;
238 return 0;
239 }
240
241 search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
242 ret = __btrfs_cow_block(trans, root, buf, parent,
243 parent_slot, cow_ret, search_start, 0);
244 return ret;
245 }
246
247 /*
248 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
249 {
250 if (blocknr < other && other - (blocknr + blocksize) < 32768)
251 return 1;
252 if (blocknr > other && blocknr - (other + blocksize) < 32768)
253 return 1;
254 return 0;
255 }
256 */
257
258 /*
259 * compare two keys in a memcmp fashion
260 */
261 int btrfs_comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
262 {
263 struct btrfs_key k1;
264
265 btrfs_disk_key_to_cpu(&k1, disk);
266
267 if (k1.objectid > k2->objectid)
268 return 1;
269 if (k1.objectid < k2->objectid)
270 return -1;
271 if (k1.type > k2->type)
272 return 1;
273 if (k1.type < k2->type)
274 return -1;
275 if (k1.offset > k2->offset)
276 return 1;
277 if (k1.offset < k2->offset)
278 return -1;
279 return 0;
280 }
281
282
283 #if 0
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 gen;
293 u64 search_start = *last_ret;
294 u64 last_block = 0;
295 u64 other;
296 u32 parent_nritems;
297 int end_slot;
298 int i;
299 int err = 0;
300 int parent_level;
301 int uptodate;
302 u32 blocksize;
303 int progress_passed = 0;
304 struct btrfs_disk_key disk_key;
305
306 parent_level = btrfs_header_level(parent);
307 if (cache_only && parent_level != 1)
308 return 0;
309
310 if (trans->transaction != root->fs_info->running_transaction) {
311 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
312 root->fs_info->running_transaction->transid);
313 WARN_ON(1);
314 }
315 if (trans->transid != root->fs_info->generation) {
316 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
317 root->fs_info->generation);
318 WARN_ON(1);
319 }
320
321 parent_nritems = btrfs_header_nritems(parent);
322 blocksize = btrfs_level_size(root, parent_level - 1);
323 end_slot = parent_nritems;
324
325 if (parent_nritems == 1)
326 return 0;
327
328 for (i = start_slot; i < end_slot; i++) {
329 int close = 1;
330
331 if (!parent->map_token) {
332 map_extent_buffer(parent,
333 btrfs_node_key_ptr_offset(i),
334 sizeof(struct btrfs_key_ptr),
335 &parent->map_token, &parent->kaddr,
336 &parent->map_start, &parent->map_len,
337 KM_USER1);
338 }
339 btrfs_node_key(parent, &disk_key, i);
340 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
341 continue;
342
343 progress_passed = 1;
344 blocknr = btrfs_node_blockptr(parent, i);
345 gen = btrfs_node_ptr_generation(parent, i);
346 if (last_block == 0)
347 last_block = blocknr;
348
349 if (i > 0) {
350 other = btrfs_node_blockptr(parent, i - 1);
351 close = close_blocks(blocknr, other, blocksize);
352 }
353 if (close && i < end_slot - 2) {
354 other = btrfs_node_blockptr(parent, i + 1);
355 close = close_blocks(blocknr, other, blocksize);
356 }
357 if (close) {
358 last_block = blocknr;
359 continue;
360 }
361 if (parent->map_token) {
362 unmap_extent_buffer(parent, parent->map_token,
363 KM_USER1);
364 parent->map_token = NULL;
365 }
366
367 cur = btrfs_find_tree_block(root, blocknr, blocksize);
368 if (cur)
369 uptodate = btrfs_buffer_uptodate(cur, gen);
370 else
371 uptodate = 0;
372 if (!cur || !uptodate) {
373 if (cache_only) {
374 free_extent_buffer(cur);
375 continue;
376 }
377 if (!cur) {
378 cur = read_tree_block(root, blocknr,
379 blocksize, gen);
380 } else if (!uptodate) {
381 btrfs_read_buffer(cur, gen);
382 }
383 }
384 if (search_start == 0)
385 search_start = last_block;
386
387 err = __btrfs_cow_block(trans, root, cur, parent, i,
388 &tmp, search_start,
389 min(16 * blocksize,
390 (end_slot - i) * blocksize));
391 if (err) {
392 free_extent_buffer(cur);
393 break;
394 }
395 search_start = tmp->start;
396 last_block = tmp->start;
397 *last_ret = search_start;
398 if (parent_level == 1)
399 btrfs_clear_buffer_defrag(tmp);
400 free_extent_buffer(tmp);
401 }
402 if (parent->map_token) {
403 unmap_extent_buffer(parent, parent->map_token,
404 KM_USER1);
405 parent->map_token = NULL;
406 }
407 return err;
408 }
409 #endif
410
411 /*
412 * The leaf data grows from end-to-front in the node.
413 * this returns the address of the start of the last item,
414 * which is the stop of the leaf data stack
415 */
416 static inline unsigned int leaf_data_end(struct btrfs_root *root,
417 struct extent_buffer *leaf)
418 {
419 u32 nr = btrfs_header_nritems(leaf);
420 if (nr == 0)
421 return BTRFS_LEAF_DATA_SIZE(root);
422 return btrfs_item_offset_nr(leaf, nr - 1);
423 }
424
425 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
426 int level)
427 {
428 struct extent_buffer *parent = NULL;
429 struct extent_buffer *node = path->nodes[level];
430 struct btrfs_disk_key parent_key;
431 struct btrfs_disk_key node_key;
432 int parent_slot;
433 int slot;
434 struct btrfs_key cpukey;
435 u32 nritems = btrfs_header_nritems(node);
436
437 if (path->nodes[level + 1])
438 parent = path->nodes[level + 1];
439
440 slot = path->slots[level];
441 BUG_ON(nritems == 0);
442 if (parent) {
443 parent_slot = path->slots[level + 1];
444 btrfs_node_key(parent, &parent_key, parent_slot);
445 btrfs_node_key(node, &node_key, 0);
446 BUG_ON(memcmp(&parent_key, &node_key,
447 sizeof(struct btrfs_disk_key)));
448 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
449 btrfs_header_bytenr(node));
450 }
451 BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
452 if (slot != 0) {
453 btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
454 btrfs_node_key(node, &node_key, slot);
455 BUG_ON(btrfs_comp_keys(&node_key, &cpukey) <= 0);
456 }
457 if (slot < nritems - 1) {
458 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
459 btrfs_node_key(node, &node_key, slot);
460 BUG_ON(btrfs_comp_keys(&node_key, &cpukey) >= 0);
461 }
462 return 0;
463 }
464
465 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
466 int level)
467 {
468 struct extent_buffer *leaf = path->nodes[level];
469 struct extent_buffer *parent = NULL;
470 int parent_slot;
471 struct btrfs_key cpukey;
472 struct btrfs_disk_key parent_key;
473 struct btrfs_disk_key leaf_key;
474 int slot = path->slots[0];
475
476 u32 nritems = btrfs_header_nritems(leaf);
477
478 if (path->nodes[level + 1])
479 parent = path->nodes[level + 1];
480
481 if (nritems == 0)
482 return 0;
483
484 if (parent) {
485 parent_slot = path->slots[level + 1];
486 btrfs_node_key(parent, &parent_key, parent_slot);
487 btrfs_item_key(leaf, &leaf_key, 0);
488
489 BUG_ON(memcmp(&parent_key, &leaf_key,
490 sizeof(struct btrfs_disk_key)));
491 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
492 btrfs_header_bytenr(leaf));
493 }
494 #if 0
495 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
496 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
497 btrfs_item_key(leaf, &leaf_key, i);
498 if (comp_keys(&leaf_key, &cpukey) >= 0) {
499 btrfs_print_leaf(root, leaf);
500 printk("slot %d offset bad key\n", i);
501 BUG_ON(1);
502 }
503 if (btrfs_item_offset_nr(leaf, i) !=
504 btrfs_item_end_nr(leaf, i + 1)) {
505 btrfs_print_leaf(root, leaf);
506 printk("slot %d offset bad\n", i);
507 BUG_ON(1);
508 }
509 if (i == 0) {
510 if (btrfs_item_offset_nr(leaf, i) +
511 btrfs_item_size_nr(leaf, i) !=
512 BTRFS_LEAF_DATA_SIZE(root)) {
513 btrfs_print_leaf(root, leaf);
514 printk("slot %d first offset bad\n", i);
515 BUG_ON(1);
516 }
517 }
518 }
519 if (nritems > 0) {
520 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
521 btrfs_print_leaf(root, leaf);
522 printk("slot %d bad size \n", nritems - 1);
523 BUG_ON(1);
524 }
525 }
526 #endif
527 if (slot != 0 && slot < nritems - 1) {
528 btrfs_item_key(leaf, &leaf_key, slot);
529 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
530 if (btrfs_comp_keys(&leaf_key, &cpukey) <= 0) {
531 btrfs_print_leaf(root, leaf);
532 printk("slot %d offset bad key\n", slot);
533 BUG_ON(1);
534 }
535 if (btrfs_item_offset_nr(leaf, slot - 1) !=
536 btrfs_item_end_nr(leaf, slot)) {
537 btrfs_print_leaf(root, leaf);
538 printk("slot %d offset bad\n", slot);
539 BUG_ON(1);
540 }
541 }
542 if (slot < nritems - 1) {
543 btrfs_item_key(leaf, &leaf_key, slot);
544 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
545 BUG_ON(btrfs_comp_keys(&leaf_key, &cpukey) >= 0);
546 if (btrfs_item_offset_nr(leaf, slot) !=
547 btrfs_item_end_nr(leaf, slot + 1)) {
548 btrfs_print_leaf(root, leaf);
549 printk("slot %d offset bad\n", slot);
550 BUG_ON(1);
551 }
552 }
553 BUG_ON(btrfs_item_offset_nr(leaf, 0) +
554 btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
555 return 0;
556 }
557
558 static int noinline check_block(struct btrfs_root *root,
559 struct btrfs_path *path, int level)
560 {
561 return 0;
562 #if 0
563 struct extent_buffer *buf = path->nodes[level];
564
565 if (memcmp_extent_buffer(buf, root->fs_info->fsid,
566 (unsigned long)btrfs_header_fsid(buf),
567 BTRFS_FSID_SIZE)) {
568 printk("warning bad block %Lu\n", buf->start);
569 return 1;
570 }
571 #endif
572 if (level == 0)
573 return check_leaf(root, path, level);
574 return check_node(root, path, level);
575 }
576
577 /*
578 * search for key in the extent_buffer. The items start at offset p,
579 * and they are item_size apart. There are 'max' items in p.
580 *
581 * the slot in the array is returned via slot, and it points to
582 * the place where you would insert key if it is not found in
583 * the array.
584 *
585 * slot may point to max if the key is bigger than all of the keys
586 */
587 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
588 int item_size, struct btrfs_key *key,
589 int max, int *slot)
590 {
591 int low = 0;
592 int high = max;
593 int mid;
594 int ret;
595 unsigned long offset;
596 struct btrfs_disk_key *tmp;
597
598 while(low < high) {
599 mid = (low + high) / 2;
600 offset = p + mid * item_size;
601
602 tmp = (struct btrfs_disk_key *)(eb->data + offset);
603 ret = btrfs_comp_keys(tmp, key);
604
605 if (ret < 0)
606 low = mid + 1;
607 else if (ret > 0)
608 high = mid;
609 else {
610 *slot = mid;
611 return 0;
612 }
613 }
614 *slot = low;
615 return 1;
616 }
617
618 /*
619 * simple bin_search frontend that does the right thing for
620 * leaves vs nodes
621 */
622 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
623 int level, int *slot)
624 {
625 if (level == 0) {
626 return generic_bin_search(eb,
627 offsetof(struct btrfs_leaf, items),
628 sizeof(struct btrfs_item),
629 key, btrfs_header_nritems(eb),
630 slot);
631 } else {
632 return generic_bin_search(eb,
633 offsetof(struct btrfs_node, ptrs),
634 sizeof(struct btrfs_key_ptr),
635 key, btrfs_header_nritems(eb),
636 slot);
637 }
638 return -1;
639 }
640
641 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
642 struct extent_buffer *parent, int slot)
643 {
644 int level = btrfs_header_level(parent);
645 if (slot < 0)
646 return NULL;
647 if (slot >= btrfs_header_nritems(parent))
648 return NULL;
649
650 BUG_ON(level == 0);
651
652 return read_tree_block(root, btrfs_node_blockptr(parent, slot),
653 btrfs_level_size(root, level - 1),
654 btrfs_node_ptr_generation(parent, slot));
655 }
656
657 static int balance_level(struct btrfs_trans_handle *trans,
658 struct btrfs_root *root,
659 struct btrfs_path *path, int level)
660 {
661 struct extent_buffer *right = NULL;
662 struct extent_buffer *mid;
663 struct extent_buffer *left = NULL;
664 struct extent_buffer *parent = NULL;
665 int ret = 0;
666 int wret;
667 int pslot;
668 int orig_slot = path->slots[level];
669 int err_on_enospc = 0;
670 u64 orig_ptr;
671
672 if (level == 0)
673 return 0;
674
675 mid = path->nodes[level];
676 WARN_ON(btrfs_header_generation(mid) != trans->transid);
677
678 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
679
680 if (level < BTRFS_MAX_LEVEL - 1)
681 parent = path->nodes[level + 1];
682 pslot = path->slots[level + 1];
683
684 /*
685 * deal with the case where there is only one pointer in the root
686 * by promoting the node below to a root
687 */
688 if (!parent) {
689 struct extent_buffer *child;
690
691 if (btrfs_header_nritems(mid) != 1)
692 return 0;
693
694 /* promote the child to a root */
695 child = read_node_slot(root, mid, 0);
696 BUG_ON(!child);
697 ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
698 BUG_ON(ret);
699
700 root->node = child;
701
702 ret = btrfs_update_extent_ref(trans, root, child->start,
703 mid->start, child->start,
704 root->root_key.objectid,
705 trans->transid, level - 1);
706 BUG_ON(ret);
707
708 add_root_to_dirty_list(root);
709 path->nodes[level] = NULL;
710 clean_tree_block(trans, root, mid);
711 wait_on_tree_block_writeback(root, mid);
712 /* once for the path */
713 free_extent_buffer(mid);
714 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
715 mid->start, root->root_key.objectid,
716 btrfs_header_generation(mid),
717 level, 1);
718 /* once for the root ptr */
719 free_extent_buffer(mid);
720 return ret;
721 }
722 if (btrfs_header_nritems(mid) >
723 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
724 return 0;
725
726 if (btrfs_header_nritems(mid) < 2)
727 err_on_enospc = 1;
728
729 left = read_node_slot(root, parent, pslot - 1);
730 if (left) {
731 wret = btrfs_cow_block(trans, root, left,
732 parent, pslot - 1, &left);
733 if (wret) {
734 ret = wret;
735 goto enospc;
736 }
737 }
738 right = read_node_slot(root, parent, pslot + 1);
739 if (right) {
740 wret = btrfs_cow_block(trans, root, right,
741 parent, pslot + 1, &right);
742 if (wret) {
743 ret = wret;
744 goto enospc;
745 }
746 }
747
748 /* first, try to make some room in the middle buffer */
749 if (left) {
750 orig_slot += btrfs_header_nritems(left);
751 wret = push_node_left(trans, root, left, mid, 1);
752 if (wret < 0)
753 ret = wret;
754 if (btrfs_header_nritems(mid) < 2)
755 err_on_enospc = 1;
756 }
757
758 /*
759 * then try to empty the right most buffer into the middle
760 */
761 if (right) {
762 wret = push_node_left(trans, root, mid, right, 1);
763 if (wret < 0 && wret != -ENOSPC)
764 ret = wret;
765 if (btrfs_header_nritems(right) == 0) {
766 u64 bytenr = right->start;
767 u64 generation = btrfs_header_generation(parent);
768 u32 blocksize = right->len;
769
770 clean_tree_block(trans, root, right);
771 wait_on_tree_block_writeback(root, right);
772 free_extent_buffer(right);
773 right = NULL;
774 wret = del_ptr(trans, root, path, level + 1, pslot +
775 1);
776 if (wret)
777 ret = wret;
778 wret = btrfs_free_extent(trans, root, bytenr,
779 blocksize, parent->start,
780 btrfs_header_owner(parent),
781 generation, level, 1);
782 if (wret)
783 ret = wret;
784 } else {
785 struct btrfs_disk_key right_key;
786 btrfs_node_key(right, &right_key, 0);
787 btrfs_set_node_key(parent, &right_key, pslot + 1);
788 btrfs_mark_buffer_dirty(parent);
789 }
790 }
791 if (btrfs_header_nritems(mid) == 1) {
792 /*
793 * we're not allowed to leave a node with one item in the
794 * tree during a delete. A deletion from lower in the tree
795 * could try to delete the only pointer in this node.
796 * So, pull some keys from the left.
797 * There has to be a left pointer at this point because
798 * otherwise we would have pulled some pointers from the
799 * right
800 */
801 BUG_ON(!left);
802 wret = balance_node_right(trans, root, mid, left);
803 if (wret < 0) {
804 ret = wret;
805 goto enospc;
806 }
807 if (wret == 1) {
808 wret = push_node_left(trans, root, left, mid, 1);
809 if (wret < 0)
810 ret = wret;
811 }
812 BUG_ON(wret == 1);
813 }
814 if (btrfs_header_nritems(mid) == 0) {
815 /* we've managed to empty the middle node, drop it */
816 u64 root_gen = btrfs_header_generation(parent);
817 u64 bytenr = mid->start;
818 u32 blocksize = mid->len;
819 clean_tree_block(trans, root, mid);
820 wait_on_tree_block_writeback(root, mid);
821 free_extent_buffer(mid);
822 mid = NULL;
823 wret = del_ptr(trans, root, path, level + 1, pslot);
824 if (wret)
825 ret = wret;
826 wret = btrfs_free_extent(trans, root, bytenr, blocksize,
827 parent->start,
828 btrfs_header_owner(parent),
829 root_gen, level, 1);
830 if (wret)
831 ret = wret;
832 } else {
833 /* update the parent key to reflect our changes */
834 struct btrfs_disk_key mid_key;
835 btrfs_node_key(mid, &mid_key, 0);
836 btrfs_set_node_key(parent, &mid_key, pslot);
837 btrfs_mark_buffer_dirty(parent);
838 }
839
840 /* update the path */
841 if (left) {
842 if (btrfs_header_nritems(left) > orig_slot) {
843 extent_buffer_get(left);
844 path->nodes[level] = left;
845 path->slots[level + 1] -= 1;
846 path->slots[level] = orig_slot;
847 if (mid)
848 free_extent_buffer(mid);
849 } else {
850 orig_slot -= btrfs_header_nritems(left);
851 path->slots[level] = orig_slot;
852 }
853 }
854 /* double check we haven't messed things up */
855 check_block(root, path, level);
856 if (orig_ptr !=
857 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
858 BUG();
859 enospc:
860 if (right)
861 free_extent_buffer(right);
862 if (left)
863 free_extent_buffer(left);
864 return ret;
865 }
866
867 /* returns zero if the push worked, non-zero otherwise */
868 static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
869 struct btrfs_root *root,
870 struct btrfs_path *path, int level)
871 {
872 struct extent_buffer *right = NULL;
873 struct extent_buffer *mid;
874 struct extent_buffer *left = NULL;
875 struct extent_buffer *parent = NULL;
876 int ret = 0;
877 int wret;
878 int pslot;
879 int orig_slot = path->slots[level];
880 u64 orig_ptr;
881
882 if (level == 0)
883 return 1;
884
885 mid = path->nodes[level];
886 WARN_ON(btrfs_header_generation(mid) != trans->transid);
887 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
888
889 if (level < BTRFS_MAX_LEVEL - 1)
890 parent = path->nodes[level + 1];
891 pslot = path->slots[level + 1];
892
893 if (!parent)
894 return 1;
895
896 left = read_node_slot(root, parent, pslot - 1);
897
898 /* first, try to make some room in the middle buffer */
899 if (left) {
900 u32 left_nr;
901 left_nr = btrfs_header_nritems(left);
902 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
903 wret = 1;
904 } else {
905 ret = btrfs_cow_block(trans, root, left, parent,
906 pslot - 1, &left);
907 if (ret)
908 wret = 1;
909 else {
910 wret = push_node_left(trans, root,
911 left, mid, 0);
912 }
913 }
914 if (wret < 0)
915 ret = wret;
916 if (wret == 0) {
917 struct btrfs_disk_key disk_key;
918 orig_slot += left_nr;
919 btrfs_node_key(mid, &disk_key, 0);
920 btrfs_set_node_key(parent, &disk_key, pslot);
921 btrfs_mark_buffer_dirty(parent);
922 if (btrfs_header_nritems(left) > orig_slot) {
923 path->nodes[level] = left;
924 path->slots[level + 1] -= 1;
925 path->slots[level] = orig_slot;
926 free_extent_buffer(mid);
927 } else {
928 orig_slot -=
929 btrfs_header_nritems(left);
930 path->slots[level] = orig_slot;
931 free_extent_buffer(left);
932 }
933 return 0;
934 }
935 free_extent_buffer(left);
936 }
937 right= read_node_slot(root, parent, pslot + 1);
938
939 /*
940 * then try to empty the right most buffer into the middle
941 */
942 if (right) {
943 u32 right_nr;
944 right_nr = btrfs_header_nritems(right);
945 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
946 wret = 1;
947 } else {
948 ret = btrfs_cow_block(trans, root, right,
949 parent, pslot + 1,
950 &right);
951 if (ret)
952 wret = 1;
953 else {
954 wret = balance_node_right(trans, root,
955 right, mid);
956 }
957 }
958 if (wret < 0)
959 ret = wret;
960 if (wret == 0) {
961 struct btrfs_disk_key disk_key;
962
963 btrfs_node_key(right, &disk_key, 0);
964 btrfs_set_node_key(parent, &disk_key, pslot + 1);
965 btrfs_mark_buffer_dirty(parent);
966
967 if (btrfs_header_nritems(mid) <= orig_slot) {
968 path->nodes[level] = right;
969 path->slots[level + 1] += 1;
970 path->slots[level] = orig_slot -
971 btrfs_header_nritems(mid);
972 free_extent_buffer(mid);
973 } else {
974 free_extent_buffer(right);
975 }
976 return 0;
977 }
978 free_extent_buffer(right);
979 }
980 return 1;
981 }
982
983 /*
984 * readahead one full node of leaves
985 */
986 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
987 int level, int slot, u64 objectid)
988 {
989 struct extent_buffer *node;
990 struct btrfs_disk_key disk_key;
991 u32 nritems;
992 u64 search;
993 u64 lowest_read;
994 u64 highest_read;
995 u64 nread = 0;
996 int direction = path->reada;
997 struct extent_buffer *eb;
998 u32 nr;
999 u32 blocksize;
1000 u32 nscan = 0;
1001
1002 if (level != 1)
1003 return;
1004
1005 if (!path->nodes[level])
1006 return;
1007
1008 node = path->nodes[level];
1009 search = btrfs_node_blockptr(node, slot);
1010 blocksize = btrfs_level_size(root, level - 1);
1011 eb = btrfs_find_tree_block(root, search, blocksize);
1012 if (eb) {
1013 free_extent_buffer(eb);
1014 return;
1015 }
1016
1017 highest_read = search;
1018 lowest_read = search;
1019
1020 nritems = btrfs_header_nritems(node);
1021 nr = slot;
1022 while(1) {
1023 if (direction < 0) {
1024 if (nr == 0)
1025 break;
1026 nr--;
1027 } else if (direction > 0) {
1028 nr++;
1029 if (nr >= nritems)
1030 break;
1031 }
1032 if (path->reada < 0 && objectid) {
1033 btrfs_node_key(node, &disk_key, nr);
1034 if (btrfs_disk_key_objectid(&disk_key) != objectid)
1035 break;
1036 }
1037 search = btrfs_node_blockptr(node, nr);
1038 if ((search >= lowest_read && search <= highest_read) ||
1039 (search < lowest_read && lowest_read - search <= 32768) ||
1040 (search > highest_read && search - highest_read <= 32768)) {
1041 readahead_tree_block(root, search, blocksize,
1042 btrfs_node_ptr_generation(node, nr));
1043 nread += blocksize;
1044 }
1045 nscan++;
1046 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
1047 break;
1048 if(nread > (1024 * 1024) || nscan > 128)
1049 break;
1050
1051 if (search < lowest_read)
1052 lowest_read = search;
1053 if (search > highest_read)
1054 highest_read = search;
1055 }
1056 }
1057
1058 /*
1059 * look for key in the tree. path is filled in with nodes along the way
1060 * if key is found, we return zero and you can find the item in the leaf
1061 * level of the path (level 0)
1062 *
1063 * If the key isn't found, the path points to the slot where it should
1064 * be inserted, and 1 is returned. If there are other errors during the
1065 * search a negative error number is returned.
1066 *
1067 * if ins_len > 0, nodes and leaves will be split as we walk down the
1068 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
1069 * possible)
1070 */
1071 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
1072 *root, struct btrfs_key *key, struct btrfs_path *p, int
1073 ins_len, int cow)
1074 {
1075 struct extent_buffer *b;
1076 int slot;
1077 int ret;
1078 int level;
1079 int should_reada = p->reada;
1080 u8 lowest_level = 0;
1081
1082 lowest_level = p->lowest_level;
1083 WARN_ON(lowest_level && ins_len);
1084 WARN_ON(p->nodes[0] != NULL);
1085 /*
1086 WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
1087 */
1088 again:
1089 b = root->node;
1090 extent_buffer_get(b);
1091 while (b) {
1092 level = btrfs_header_level(b);
1093 if (cow) {
1094 int wret;
1095 wret = btrfs_cow_block(trans, root, b,
1096 p->nodes[level + 1],
1097 p->slots[level + 1],
1098 &b);
1099 if (wret) {
1100 free_extent_buffer(b);
1101 return wret;
1102 }
1103 }
1104 BUG_ON(!cow && ins_len);
1105 if (level != btrfs_header_level(b))
1106 WARN_ON(1);
1107 level = btrfs_header_level(b);
1108 p->nodes[level] = b;
1109 ret = check_block(root, p, level);
1110 if (ret)
1111 return -1;
1112 ret = bin_search(b, key, level, &slot);
1113 if (level != 0) {
1114 if (ret && slot > 0)
1115 slot -= 1;
1116 p->slots[level] = slot;
1117 if ((p->search_for_split || ins_len > 0) &&
1118 btrfs_header_nritems(b) >=
1119 BTRFS_NODEPTRS_PER_BLOCK(root) - 3) {
1120 int sret = split_node(trans, root, p, level);
1121 BUG_ON(sret > 0);
1122 if (sret)
1123 return sret;
1124 b = p->nodes[level];
1125 slot = p->slots[level];
1126 } else if (ins_len < 0) {
1127 int sret = balance_level(trans, root, p,
1128 level);
1129 if (sret)
1130 return sret;
1131 b = p->nodes[level];
1132 if (!b) {
1133 btrfs_release_path(NULL, p);
1134 goto again;
1135 }
1136 slot = p->slots[level];
1137 BUG_ON(btrfs_header_nritems(b) == 1);
1138 }
1139 /* this is only true while dropping a snapshot */
1140 if (level == lowest_level)
1141 break;
1142
1143 if (should_reada)
1144 reada_for_search(root, p, level, slot,
1145 key->objectid);
1146
1147 b = read_node_slot(root, b, slot);
1148 } else {
1149 p->slots[level] = slot;
1150 if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1151 sizeof(struct btrfs_item) + ins_len) {
1152 int sret = split_leaf(trans, root, key,
1153 p, ins_len, ret == 0);
1154 BUG_ON(sret > 0);
1155 if (sret)
1156 return sret;
1157 }
1158 return ret;
1159 }
1160 }
1161 return 1;
1162 }
1163
1164 /*
1165 * adjust the pointers going up the tree, starting at level
1166 * making sure the right key of each node is points to 'key'.
1167 * This is used after shifting pointers to the left, so it stops
1168 * fixing up pointers when a given leaf/node is not in slot 0 of the
1169 * higher levels
1170 *
1171 * If this fails to write a tree block, it returns -1, but continues
1172 * fixing up the blocks in ram so the tree is consistent.
1173 */
1174 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1175 struct btrfs_root *root, struct btrfs_path *path,
1176 struct btrfs_disk_key *key, int level)
1177 {
1178 int i;
1179 int ret = 0;
1180 struct extent_buffer *t;
1181
1182 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1183 int tslot = path->slots[i];
1184 if (!path->nodes[i])
1185 break;
1186 t = path->nodes[i];
1187 btrfs_set_node_key(t, key, tslot);
1188 btrfs_mark_buffer_dirty(path->nodes[i]);
1189 if (tslot != 0)
1190 break;
1191 }
1192 return ret;
1193 }
1194
1195 /*
1196 * update item key.
1197 *
1198 * This function isn't completely safe. It's the caller's responsibility
1199 * that the new key won't break the order
1200 */
1201 int btrfs_set_item_key_safe(struct btrfs_trans_handle *trans,
1202 struct btrfs_root *root, struct btrfs_path *path,
1203 struct btrfs_key *new_key)
1204 {
1205 struct btrfs_disk_key disk_key;
1206 struct extent_buffer *eb;
1207 int slot;
1208
1209 eb = path->nodes[0];
1210 slot = path->slots[0];
1211 if (slot > 0) {
1212 btrfs_item_key(eb, &disk_key, slot - 1);
1213 if (btrfs_comp_keys(&disk_key, new_key) >= 0)
1214 return -1;
1215 }
1216 if (slot < btrfs_header_nritems(eb) - 1) {
1217 btrfs_item_key(eb, &disk_key, slot + 1);
1218 if (btrfs_comp_keys(&disk_key, new_key) <= 0)
1219 return -1;
1220 }
1221
1222 btrfs_cpu_key_to_disk(&disk_key, new_key);
1223 btrfs_set_item_key(eb, &disk_key, slot);
1224 btrfs_mark_buffer_dirty(eb);
1225 if (slot == 0)
1226 fixup_low_keys(trans, root, path, &disk_key, 1);
1227 return 0;
1228 }
1229
1230 /*
1231 * try to push data from one node into the next node left in the
1232 * tree.
1233 *
1234 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1235 * error, and > 0 if there was no room in the left hand block.
1236 */
1237 static int push_node_left(struct btrfs_trans_handle *trans,
1238 struct btrfs_root *root, struct extent_buffer *dst,
1239 struct extent_buffer *src, int empty)
1240 {
1241 int push_items = 0;
1242 int src_nritems;
1243 int dst_nritems;
1244 int ret = 0;
1245
1246 src_nritems = btrfs_header_nritems(src);
1247 dst_nritems = btrfs_header_nritems(dst);
1248 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1249 WARN_ON(btrfs_header_generation(src) != trans->transid);
1250 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1251
1252 if (!empty && src_nritems <= 8)
1253 return 1;
1254
1255 if (push_items <= 0) {
1256 return 1;
1257 }
1258
1259 if (empty) {
1260 push_items = min(src_nritems, push_items);
1261 if (push_items < src_nritems) {
1262 /* leave at least 8 pointers in the node if
1263 * we aren't going to empty it
1264 */
1265 if (src_nritems - push_items < 8) {
1266 if (push_items <= 8)
1267 return 1;
1268 push_items -= 8;
1269 }
1270 }
1271 } else
1272 push_items = min(src_nritems - 8, push_items);
1273
1274 copy_extent_buffer(dst, src,
1275 btrfs_node_key_ptr_offset(dst_nritems),
1276 btrfs_node_key_ptr_offset(0),
1277 push_items * sizeof(struct btrfs_key_ptr));
1278
1279 if (push_items < src_nritems) {
1280 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1281 btrfs_node_key_ptr_offset(push_items),
1282 (src_nritems - push_items) *
1283 sizeof(struct btrfs_key_ptr));
1284 }
1285 btrfs_set_header_nritems(src, src_nritems - push_items);
1286 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1287 btrfs_mark_buffer_dirty(src);
1288 btrfs_mark_buffer_dirty(dst);
1289
1290 ret = btrfs_update_ref(trans, root, src, dst, dst_nritems, push_items);
1291 BUG_ON(ret);
1292 return ret;
1293 }
1294
1295 /*
1296 * try to push data from one node into the next node right in the
1297 * tree.
1298 *
1299 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1300 * error, and > 0 if there was no room in the right hand block.
1301 *
1302 * this will only push up to 1/2 the contents of the left node over
1303 */
1304 static int balance_node_right(struct btrfs_trans_handle *trans,
1305 struct btrfs_root *root,
1306 struct extent_buffer *dst,
1307 struct extent_buffer *src)
1308 {
1309 int push_items = 0;
1310 int max_push;
1311 int src_nritems;
1312 int dst_nritems;
1313 int ret = 0;
1314
1315 WARN_ON(btrfs_header_generation(src) != trans->transid);
1316 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1317
1318 src_nritems = btrfs_header_nritems(src);
1319 dst_nritems = btrfs_header_nritems(dst);
1320 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1321 if (push_items <= 0) {
1322 return 1;
1323 }
1324
1325 if (src_nritems < 4) {
1326 return 1;
1327 }
1328
1329 max_push = src_nritems / 2 + 1;
1330 /* don't try to empty the node */
1331 if (max_push >= src_nritems) {
1332 return 1;
1333 }
1334
1335 if (max_push < push_items)
1336 push_items = max_push;
1337
1338 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1339 btrfs_node_key_ptr_offset(0),
1340 (dst_nritems) *
1341 sizeof(struct btrfs_key_ptr));
1342
1343 copy_extent_buffer(dst, src,
1344 btrfs_node_key_ptr_offset(0),
1345 btrfs_node_key_ptr_offset(src_nritems - push_items),
1346 push_items * sizeof(struct btrfs_key_ptr));
1347
1348 btrfs_set_header_nritems(src, src_nritems - push_items);
1349 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1350
1351 btrfs_mark_buffer_dirty(src);
1352 btrfs_mark_buffer_dirty(dst);
1353
1354 ret = btrfs_update_ref(trans, root, src, dst, 0, push_items);
1355 BUG_ON(ret);
1356 return ret;
1357 }
1358
1359 /*
1360 * helper function to insert a new root level in the tree.
1361 * A new node is allocated, and a single item is inserted to
1362 * point to the existing root
1363 *
1364 * returns zero on success or < 0 on failure.
1365 */
1366 static int noinline insert_new_root(struct btrfs_trans_handle *trans,
1367 struct btrfs_root *root,
1368 struct btrfs_path *path, int level)
1369 {
1370 u64 lower_gen;
1371 struct extent_buffer *lower;
1372 struct extent_buffer *c;
1373 struct extent_buffer *old;
1374 struct btrfs_disk_key lower_key;
1375 int ret;
1376
1377 BUG_ON(path->nodes[level]);
1378 BUG_ON(path->nodes[level-1] != root->node);
1379
1380 lower = path->nodes[level-1];
1381 if (level == 1)
1382 btrfs_item_key(lower, &lower_key, 0);
1383 else
1384 btrfs_node_key(lower, &lower_key, 0);
1385
1386 c = btrfs_alloc_free_block(trans, root, root->nodesize, 0,
1387 root->root_key.objectid,
1388 trans->transid, level,
1389 root->node->start, 0);
1390 if (IS_ERR(c))
1391 return PTR_ERR(c);
1392
1393 memset_extent_buffer(c, 0, 0, root->nodesize);
1394 btrfs_set_header_nritems(c, 1);
1395 btrfs_set_header_level(c, level);
1396 btrfs_set_header_bytenr(c, c->start);
1397 btrfs_set_header_generation(c, trans->transid);
1398 btrfs_set_header_owner(c, root->root_key.objectid);
1399
1400 write_extent_buffer(c, root->fs_info->fsid,
1401 (unsigned long)btrfs_header_fsid(c),
1402 BTRFS_FSID_SIZE);
1403
1404 write_extent_buffer(c, root->fs_info->chunk_tree_uuid,
1405 (unsigned long)btrfs_header_chunk_tree_uuid(c),
1406 BTRFS_UUID_SIZE);
1407
1408 btrfs_set_node_key(c, &lower_key, 0);
1409 btrfs_set_node_blockptr(c, 0, lower->start);
1410 lower_gen = btrfs_header_generation(lower);
1411 WARN_ON(lower_gen != trans->transid);
1412
1413 btrfs_set_node_ptr_generation(c, 0, lower_gen);
1414
1415 btrfs_mark_buffer_dirty(c);
1416
1417 old = root->node;
1418 root->node = c;
1419
1420 ret = btrfs_update_extent_ref(trans, root, lower->start,
1421 lower->start, c->start,
1422 root->root_key.objectid,
1423 trans->transid, level - 1);
1424 BUG_ON(ret);
1425
1426 /* the super has an extra ref to root->node */
1427 free_extent_buffer(old);
1428
1429 add_root_to_dirty_list(root);
1430 extent_buffer_get(c);
1431 path->nodes[level] = c;
1432 path->slots[level] = 0;
1433 return 0;
1434 }
1435
1436 /*
1437 * worker function to insert a single pointer in a node.
1438 * the node should have enough room for the pointer already
1439 *
1440 * slot and level indicate where you want the key to go, and
1441 * blocknr is the block the key points to.
1442 *
1443 * returns zero on success and < 0 on any error
1444 */
1445 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1446 *root, struct btrfs_path *path, struct btrfs_disk_key
1447 *key, u64 bytenr, int slot, int level)
1448 {
1449 struct extent_buffer *lower;
1450 int nritems;
1451
1452 BUG_ON(!path->nodes[level]);
1453 lower = path->nodes[level];
1454 nritems = btrfs_header_nritems(lower);
1455 if (slot > nritems)
1456 BUG();
1457 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1458 BUG();
1459 if (slot != nritems) {
1460 memmove_extent_buffer(lower,
1461 btrfs_node_key_ptr_offset(slot + 1),
1462 btrfs_node_key_ptr_offset(slot),
1463 (nritems - slot) * sizeof(struct btrfs_key_ptr));
1464 }
1465 btrfs_set_node_key(lower, key, slot);
1466 btrfs_set_node_blockptr(lower, slot, bytenr);
1467 WARN_ON(trans->transid == 0);
1468 btrfs_set_node_ptr_generation(lower, slot, trans->transid);
1469 btrfs_set_header_nritems(lower, nritems + 1);
1470 btrfs_mark_buffer_dirty(lower);
1471 return 0;
1472 }
1473
1474 /*
1475 * split the node at the specified level in path in two.
1476 * The path is corrected to point to the appropriate node after the split
1477 *
1478 * Before splitting this tries to make some room in the node by pushing
1479 * left and right, if either one works, it returns right away.
1480 *
1481 * returns 0 on success and < 0 on failure
1482 */
1483 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1484 *root, struct btrfs_path *path, int level)
1485 {
1486 struct extent_buffer *c;
1487 struct extent_buffer *split;
1488 struct btrfs_disk_key disk_key;
1489 int mid;
1490 int ret;
1491 int wret;
1492 u32 c_nritems;
1493
1494 c = path->nodes[level];
1495 WARN_ON(btrfs_header_generation(c) != trans->transid);
1496 if (c == root->node) {
1497 /* trying to split the root, lets make a new one */
1498 ret = insert_new_root(trans, root, path, level + 1);
1499 if (ret)
1500 return ret;
1501 } else {
1502 ret = push_nodes_for_insert(trans, root, path, level);
1503 c = path->nodes[level];
1504 if (!ret && btrfs_header_nritems(c) <
1505 BTRFS_NODEPTRS_PER_BLOCK(root) - 3)
1506 return 0;
1507 if (ret < 0)
1508 return ret;
1509 }
1510
1511 c_nritems = btrfs_header_nritems(c);
1512
1513 btrfs_node_key(c, &disk_key, 0);
1514 split = btrfs_alloc_free_block(trans, root, root->nodesize,
1515 path->nodes[level + 1]->start,
1516 root->root_key.objectid,
1517 trans->transid, level, c->start, 0);
1518 if (IS_ERR(split))
1519 return PTR_ERR(split);
1520
1521 btrfs_set_header_flags(split, btrfs_header_flags(c));
1522 btrfs_set_header_level(split, btrfs_header_level(c));
1523 btrfs_set_header_bytenr(split, split->start);
1524 btrfs_set_header_generation(split, trans->transid);
1525 btrfs_set_header_owner(split, root->root_key.objectid);
1526 btrfs_set_header_flags(split, 0);
1527 write_extent_buffer(split, root->fs_info->fsid,
1528 (unsigned long)btrfs_header_fsid(split),
1529 BTRFS_FSID_SIZE);
1530 write_extent_buffer(split, root->fs_info->chunk_tree_uuid,
1531 (unsigned long)btrfs_header_chunk_tree_uuid(split),
1532 BTRFS_UUID_SIZE);
1533
1534 mid = (c_nritems + 1) / 2;
1535
1536 copy_extent_buffer(split, c,
1537 btrfs_node_key_ptr_offset(0),
1538 btrfs_node_key_ptr_offset(mid),
1539 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1540 btrfs_set_header_nritems(split, c_nritems - mid);
1541 btrfs_set_header_nritems(c, mid);
1542 ret = 0;
1543
1544 btrfs_mark_buffer_dirty(c);
1545 btrfs_mark_buffer_dirty(split);
1546
1547 btrfs_node_key(split, &disk_key, 0);
1548 wret = insert_ptr(trans, root, path, &disk_key, split->start,
1549 path->slots[level + 1] + 1,
1550 level + 1);
1551 if (wret)
1552 ret = wret;
1553
1554 ret = btrfs_update_ref(trans, root, c, split, 0, c_nritems - mid);
1555 BUG_ON(ret);
1556
1557 if (path->slots[level] >= mid) {
1558 path->slots[level] -= mid;
1559 free_extent_buffer(c);
1560 path->nodes[level] = split;
1561 path->slots[level + 1] += 1;
1562 } else {
1563 free_extent_buffer(split);
1564 }
1565 return ret;
1566 }
1567
1568 /*
1569 * how many bytes are required to store the items in a leaf. start
1570 * and nr indicate which items in the leaf to check. This totals up the
1571 * space used both by the item structs and the item data
1572 */
1573 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1574 {
1575 int data_len;
1576 int nritems = btrfs_header_nritems(l);
1577 int end = min(nritems, start + nr) - 1;
1578
1579 if (!nr)
1580 return 0;
1581 data_len = btrfs_item_end_nr(l, start);
1582 data_len = data_len - btrfs_item_offset_nr(l, end);
1583 data_len += sizeof(struct btrfs_item) * nr;
1584 WARN_ON(data_len < 0);
1585 return data_len;
1586 }
1587
1588 /*
1589 * The space between the end of the leaf items and
1590 * the start of the leaf data. IOW, how much room
1591 * the leaf has left for both items and data
1592 */
1593 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1594 {
1595 int nritems = btrfs_header_nritems(leaf);
1596 int ret;
1597 ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1598 if (ret < 0) {
1599 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1600 ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
1601 leaf_space_used(leaf, 0, nritems), nritems);
1602 }
1603 return ret;
1604 }
1605
1606 /*
1607 * push some data in the path leaf to the right, trying to free up at
1608 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1609 *
1610 * returns 1 if the push failed because the other node didn't have enough
1611 * room, 0 if everything worked out and < 0 if there were major errors.
1612 */
1613 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1614 *root, struct btrfs_path *path, int data_size,
1615 int empty)
1616 {
1617 struct extent_buffer *left = path->nodes[0];
1618 struct extent_buffer *right;
1619 struct extent_buffer *upper;
1620 struct btrfs_disk_key disk_key;
1621 int slot;
1622 u32 i;
1623 int free_space;
1624 int push_space = 0;
1625 int push_items = 0;
1626 struct btrfs_item *item;
1627 u32 left_nritems;
1628 u32 nr;
1629 u32 right_nritems;
1630 u32 data_end;
1631 u32 this_item_size;
1632 int ret;
1633
1634 slot = path->slots[1];
1635 if (!path->nodes[1]) {
1636 return 1;
1637 }
1638 upper = path->nodes[1];
1639 if (slot >= btrfs_header_nritems(upper) - 1)
1640 return 1;
1641
1642 right = read_node_slot(root, upper, slot + 1);
1643 free_space = btrfs_leaf_free_space(root, right);
1644 if (free_space < data_size + sizeof(struct btrfs_item)) {
1645 free_extent_buffer(right);
1646 return 1;
1647 }
1648
1649 /* cow and double check */
1650 ret = btrfs_cow_block(trans, root, right, upper,
1651 slot + 1, &right);
1652 if (ret) {
1653 free_extent_buffer(right);
1654 return 1;
1655 }
1656 free_space = btrfs_leaf_free_space(root, right);
1657 if (free_space < data_size + sizeof(struct btrfs_item)) {
1658 free_extent_buffer(right);
1659 return 1;
1660 }
1661
1662 left_nritems = btrfs_header_nritems(left);
1663 if (left_nritems == 0) {
1664 free_extent_buffer(right);
1665 return 1;
1666 }
1667
1668 if (empty)
1669 nr = 0;
1670 else
1671 nr = 1;
1672
1673 i = left_nritems - 1;
1674 while (i >= nr) {
1675 item = btrfs_item_nr(left, i);
1676
1677 if (path->slots[0] == i)
1678 push_space += data_size + sizeof(*item);
1679
1680 this_item_size = btrfs_item_size(left, item);
1681 if (this_item_size + sizeof(*item) + push_space > free_space)
1682 break;
1683 push_items++;
1684 push_space += this_item_size + sizeof(*item);
1685 if (i == 0)
1686 break;
1687 i--;
1688 }
1689
1690 if (push_items == 0) {
1691 free_extent_buffer(right);
1692 return 1;
1693 }
1694
1695 if (!empty && push_items == left_nritems)
1696 WARN_ON(1);
1697
1698 /* push left to right */
1699 right_nritems = btrfs_header_nritems(right);
1700
1701 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1702 push_space -= leaf_data_end(root, left);
1703
1704 /* make room in the right data area */
1705 data_end = leaf_data_end(root, right);
1706 memmove_extent_buffer(right,
1707 btrfs_leaf_data(right) + data_end - push_space,
1708 btrfs_leaf_data(right) + data_end,
1709 BTRFS_LEAF_DATA_SIZE(root) - data_end);
1710
1711 /* copy from the left data area */
1712 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1713 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1714 btrfs_leaf_data(left) + leaf_data_end(root, left),
1715 push_space);
1716
1717 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1718 btrfs_item_nr_offset(0),
1719 right_nritems * sizeof(struct btrfs_item));
1720
1721 /* copy the items from left to right */
1722 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1723 btrfs_item_nr_offset(left_nritems - push_items),
1724 push_items * sizeof(struct btrfs_item));
1725
1726 /* update the item pointers */
1727 right_nritems += push_items;
1728 btrfs_set_header_nritems(right, right_nritems);
1729 push_space = BTRFS_LEAF_DATA_SIZE(root);
1730 for (i = 0; i < right_nritems; i++) {
1731 item = btrfs_item_nr(right, i);
1732 push_space -= btrfs_item_size(right, item);
1733 btrfs_set_item_offset(right, item, push_space);
1734 }
1735
1736 left_nritems -= push_items;
1737 btrfs_set_header_nritems(left, left_nritems);
1738
1739 if (left_nritems)
1740 btrfs_mark_buffer_dirty(left);
1741 btrfs_mark_buffer_dirty(right);
1742
1743 btrfs_item_key(right, &disk_key, 0);
1744 btrfs_set_node_key(upper, &disk_key, slot + 1);
1745 btrfs_mark_buffer_dirty(upper);
1746
1747 ret = btrfs_update_ref(trans, root, left, right, 0, push_items);
1748 BUG_ON(ret);
1749
1750 /* then fixup the leaf pointer in the path */
1751 if (path->slots[0] >= left_nritems) {
1752 path->slots[0] -= left_nritems;
1753 free_extent_buffer(path->nodes[0]);
1754 path->nodes[0] = right;
1755 path->slots[1] += 1;
1756 } else {
1757 free_extent_buffer(right);
1758 }
1759 return 0;
1760 }
1761 /*
1762 * push some data in the path leaf to the left, trying to free up at
1763 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1764 */
1765 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1766 *root, struct btrfs_path *path, int data_size,
1767 int empty)
1768 {
1769 struct btrfs_disk_key disk_key;
1770 struct extent_buffer *right = path->nodes[0];
1771 struct extent_buffer *left;
1772 int slot;
1773 int i;
1774 int free_space;
1775 int push_space = 0;
1776 int push_items = 0;
1777 struct btrfs_item *item;
1778 u32 old_left_nritems;
1779 u32 right_nritems;
1780 u32 nr;
1781 int ret = 0;
1782 int wret;
1783 u32 this_item_size;
1784 u32 old_left_item_size;
1785
1786 slot = path->slots[1];
1787 if (slot == 0)
1788 return 1;
1789 if (!path->nodes[1])
1790 return 1;
1791
1792 right_nritems = btrfs_header_nritems(right);
1793 if (right_nritems == 0) {
1794 return 1;
1795 }
1796
1797 left = read_node_slot(root, path->nodes[1], slot - 1);
1798 free_space = btrfs_leaf_free_space(root, left);
1799 if (free_space < data_size + sizeof(struct btrfs_item)) {
1800 free_extent_buffer(left);
1801 return 1;
1802 }
1803
1804 /* cow and double check */
1805 ret = btrfs_cow_block(trans, root, left,
1806 path->nodes[1], slot - 1, &left);
1807 if (ret) {
1808 /* we hit -ENOSPC, but it isn't fatal here */
1809 free_extent_buffer(left);
1810 return 1;
1811 }
1812
1813 free_space = btrfs_leaf_free_space(root, left);
1814 if (free_space < data_size + sizeof(struct btrfs_item)) {
1815 free_extent_buffer(left);
1816 return 1;
1817 }
1818
1819 if (empty)
1820 nr = right_nritems;
1821 else
1822 nr = right_nritems - 1;
1823
1824 for (i = 0; i < nr; i++) {
1825 item = btrfs_item_nr(right, i);
1826
1827 if (path->slots[0] == i)
1828 push_space += data_size + sizeof(*item);
1829
1830 this_item_size = btrfs_item_size(right, item);
1831 if (this_item_size + sizeof(*item) + push_space > free_space)
1832 break;
1833
1834 push_items++;
1835 push_space += this_item_size + sizeof(*item);
1836 }
1837
1838 if (push_items == 0) {
1839 free_extent_buffer(left);
1840 return 1;
1841 }
1842 if (!empty && push_items == btrfs_header_nritems(right))
1843 WARN_ON(1);
1844
1845 /* push data from right to left */
1846 copy_extent_buffer(left, right,
1847 btrfs_item_nr_offset(btrfs_header_nritems(left)),
1848 btrfs_item_nr_offset(0),
1849 push_items * sizeof(struct btrfs_item));
1850
1851 push_space = BTRFS_LEAF_DATA_SIZE(root) -
1852 btrfs_item_offset_nr(right, push_items -1);
1853
1854 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
1855 leaf_data_end(root, left) - push_space,
1856 btrfs_leaf_data(right) +
1857 btrfs_item_offset_nr(right, push_items - 1),
1858 push_space);
1859 old_left_nritems = btrfs_header_nritems(left);
1860 BUG_ON(old_left_nritems < 0);
1861
1862 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
1863 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1864 u32 ioff;
1865
1866 item = btrfs_item_nr(left, i);
1867 ioff = btrfs_item_offset(left, item);
1868 btrfs_set_item_offset(left, item,
1869 ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
1870 }
1871 btrfs_set_header_nritems(left, old_left_nritems + push_items);
1872
1873 /* fixup right node */
1874 if (push_items > right_nritems) {
1875 printk("push items %d nr %u\n", push_items, right_nritems);
1876 WARN_ON(1);
1877 }
1878
1879 if (push_items < right_nritems) {
1880 push_space = btrfs_item_offset_nr(right, push_items - 1) -
1881 leaf_data_end(root, right);
1882 memmove_extent_buffer(right, btrfs_leaf_data(right) +
1883 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1884 btrfs_leaf_data(right) +
1885 leaf_data_end(root, right), push_space);
1886
1887 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
1888 btrfs_item_nr_offset(push_items),
1889 (btrfs_header_nritems(right) - push_items) *
1890 sizeof(struct btrfs_item));
1891 }
1892 right_nritems -= push_items;
1893 btrfs_set_header_nritems(right, right_nritems);
1894 push_space = BTRFS_LEAF_DATA_SIZE(root);
1895 for (i = 0; i < right_nritems; i++) {
1896 item = btrfs_item_nr(right, i);
1897 push_space = push_space - btrfs_item_size(right, item);
1898 btrfs_set_item_offset(right, item, push_space);
1899 }
1900
1901 btrfs_mark_buffer_dirty(left);
1902 if (right_nritems)
1903 btrfs_mark_buffer_dirty(right);
1904
1905 btrfs_item_key(right, &disk_key, 0);
1906 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1907 if (wret)
1908 ret = wret;
1909
1910 ret = btrfs_update_ref(trans, root, right, left,
1911 old_left_nritems, push_items);
1912 BUG_ON(ret);
1913
1914 /* then fixup the leaf pointer in the path */
1915 if (path->slots[0] < push_items) {
1916 path->slots[0] += old_left_nritems;
1917 free_extent_buffer(path->nodes[0]);
1918 path->nodes[0] = left;
1919 path->slots[1] -= 1;
1920 } else {
1921 free_extent_buffer(left);
1922 path->slots[0] -= push_items;
1923 }
1924 BUG_ON(path->slots[0] < 0);
1925 return ret;
1926 }
1927
1928 /*
1929 * split the path's leaf in two, making sure there is at least data_size
1930 * available for the resulting leaf level of the path.
1931 *
1932 * returns 0 if all went well and < 0 on failure.
1933 */
1934 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1935 *root, struct btrfs_key *ins_key,
1936 struct btrfs_path *path, int data_size, int extend)
1937 {
1938 struct extent_buffer *l;
1939 u32 nritems;
1940 int mid;
1941 int slot;
1942 struct extent_buffer *right;
1943 int space_needed = data_size + sizeof(struct btrfs_item);
1944 int data_copy_size;
1945 int rt_data_off;
1946 int i;
1947 int ret = 0;
1948 int wret;
1949 int double_split;
1950 int num_doubles = 0;
1951 struct btrfs_disk_key disk_key;
1952
1953 if (extend && data_size)
1954 space_needed = data_size;
1955
1956 /* first try to make some room by pushing left and right */
1957 if (data_size && ins_key->type != BTRFS_DIR_ITEM_KEY) {
1958 wret = push_leaf_right(trans, root, path, data_size, 0);
1959 if (wret < 0) {
1960 return wret;
1961 }
1962 if (wret) {
1963 wret = push_leaf_left(trans, root, path, data_size, 0);
1964 if (wret < 0)
1965 return wret;
1966 }
1967 l = path->nodes[0];
1968
1969 /* did the pushes work? */
1970 if (btrfs_leaf_free_space(root, l) >= space_needed)
1971 return 0;
1972 }
1973
1974 if (!path->nodes[1]) {
1975 ret = insert_new_root(trans, root, path, 1);
1976 if (ret)
1977 return ret;
1978 }
1979 again:
1980 double_split = 0;
1981 l = path->nodes[0];
1982 slot = path->slots[0];
1983 nritems = btrfs_header_nritems(l);
1984 mid = (nritems + 1)/ 2;
1985
1986 right = btrfs_alloc_free_block(trans, root, root->leafsize,
1987 path->nodes[1]->start,
1988 root->root_key.objectid,
1989 trans->transid, 0, l->start, 0);
1990 if (IS_ERR(right)) {
1991 BUG_ON(1);
1992 return PTR_ERR(right);
1993 }
1994
1995 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
1996 btrfs_set_header_bytenr(right, right->start);
1997 btrfs_set_header_generation(right, trans->transid);
1998 btrfs_set_header_owner(right, root->root_key.objectid);
1999 btrfs_set_header_level(right, 0);
2000 write_extent_buffer(right, root->fs_info->fsid,
2001 (unsigned long)btrfs_header_fsid(right),
2002 BTRFS_FSID_SIZE);
2003
2004 write_extent_buffer(right, root->fs_info->chunk_tree_uuid,
2005 (unsigned long)btrfs_header_chunk_tree_uuid(right),
2006 BTRFS_UUID_SIZE);
2007 if (mid <= slot) {
2008 if (nritems == 1 ||
2009 leaf_space_used(l, mid, nritems - mid) + space_needed >
2010 BTRFS_LEAF_DATA_SIZE(root)) {
2011 if (slot >= nritems) {
2012 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2013 btrfs_set_header_nritems(right, 0);
2014 wret = insert_ptr(trans, root, path,
2015 &disk_key, right->start,
2016 path->slots[1] + 1, 1);
2017 if (wret)
2018 ret = wret;
2019 free_extent_buffer(path->nodes[0]);
2020 path->nodes[0] = right;
2021 path->slots[0] = 0;
2022 path->slots[1] += 1;
2023 return ret;
2024 }
2025 mid = slot;
2026 if (mid != nritems &&
2027 leaf_space_used(l, mid, nritems - mid) +
2028 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2029 double_split = 1;
2030 }
2031 }
2032 } else {
2033 if (leaf_space_used(l, 0, mid + 1) + space_needed >
2034 BTRFS_LEAF_DATA_SIZE(root)) {
2035 if (!extend && data_size && slot == 0) {
2036 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2037 btrfs_set_header_nritems(right, 0);
2038 wret = insert_ptr(trans, root, path,
2039 &disk_key,
2040 right->start,
2041 path->slots[1], 1);
2042 if (wret)
2043 ret = wret;
2044 free_extent_buffer(path->nodes[0]);
2045 path->nodes[0] = right;
2046 path->slots[0] = 0;
2047 if (path->slots[1] == 0) {
2048 wret = fixup_low_keys(trans, root,
2049 path, &disk_key, 1);
2050 if (wret)
2051 ret = wret;
2052 }
2053 return ret;
2054 } else if ((extend || !data_size) && slot == 0) {
2055 mid = 1;
2056 } else {
2057 mid = slot;
2058 if (mid != nritems &&
2059 leaf_space_used(l, mid, nritems - mid) +
2060 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2061 double_split = 1;
2062 }
2063 }
2064 }
2065 }
2066 nritems = nritems - mid;
2067 btrfs_set_header_nritems(right, nritems);
2068 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
2069
2070 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
2071 btrfs_item_nr_offset(mid),
2072 nritems * sizeof(struct btrfs_item));
2073
2074 copy_extent_buffer(right, l,
2075 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
2076 data_copy_size, btrfs_leaf_data(l) +
2077 leaf_data_end(root, l), data_copy_size);
2078
2079 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
2080 btrfs_item_end_nr(l, mid);
2081
2082 for (i = 0; i < nritems; i++) {
2083 struct btrfs_item *item = btrfs_item_nr(right, i);
2084 u32 ioff = btrfs_item_offset(right, item);
2085 btrfs_set_item_offset(right, item, ioff + rt_data_off);
2086 }
2087
2088 btrfs_set_header_nritems(l, mid);
2089 ret = 0;
2090 btrfs_item_key(right, &disk_key, 0);
2091 wret = insert_ptr(trans, root, path, &disk_key, right->start,
2092 path->slots[1] + 1, 1);
2093 if (wret)
2094 ret = wret;
2095
2096 btrfs_mark_buffer_dirty(right);
2097 btrfs_mark_buffer_dirty(l);
2098 BUG_ON(path->slots[0] != slot);
2099
2100 ret = btrfs_update_ref(trans, root, l, right, 0, nritems);
2101 BUG_ON(ret);
2102
2103 if (mid <= slot) {
2104 free_extent_buffer(path->nodes[0]);
2105 path->nodes[0] = right;
2106 path->slots[0] -= mid;
2107 path->slots[1] += 1;
2108 } else
2109 free_extent_buffer(right);
2110
2111 BUG_ON(path->slots[0] < 0);
2112
2113 if (double_split) {
2114 BUG_ON(num_doubles != 0);
2115 num_doubles++;
2116 goto again;
2117 }
2118 return ret;
2119 }
2120
2121 /*
2122 * This function splits a single item into two items,
2123 * giving 'new_key' to the new item and splitting the
2124 * old one at split_offset (from the start of the item).
2125 *
2126 * The path may be released by this operation. After
2127 * the split, the path is pointing to the old item. The
2128 * new item is going to be in the same node as the old one.
2129 *
2130 * Note, the item being split must be smaller enough to live alone on
2131 * a tree block with room for one extra struct btrfs_item
2132 *
2133 * This allows us to split the item in place, keeping a lock on the
2134 * leaf the entire time.
2135 */
2136 int btrfs_split_item(struct btrfs_trans_handle *trans,
2137 struct btrfs_root *root,
2138 struct btrfs_path *path,
2139 struct btrfs_key *new_key,
2140 unsigned long split_offset)
2141 {
2142 u32 item_size;
2143 struct extent_buffer *leaf;
2144 struct btrfs_key orig_key;
2145 struct btrfs_item *item;
2146 struct btrfs_item *new_item;
2147 int ret = 0;
2148 int slot;
2149 u32 nritems;
2150 u32 orig_offset;
2151 struct btrfs_disk_key disk_key;
2152 char *buf;
2153
2154 leaf = path->nodes[0];
2155 btrfs_item_key_to_cpu(leaf, &orig_key, path->slots[0]);
2156 if (btrfs_leaf_free_space(root, leaf) >= sizeof(struct btrfs_item))
2157 goto split;
2158
2159 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2160 btrfs_release_path(root, path);
2161
2162 path->search_for_split = 1;
2163
2164 ret = btrfs_search_slot(trans, root, &orig_key, path, 0, 1);
2165 path->search_for_split = 0;
2166
2167 /* if our item isn't there or got smaller, return now */
2168 if (ret != 0 || item_size != btrfs_item_size_nr(path->nodes[0],
2169 path->slots[0])) {
2170 return -EAGAIN;
2171 }
2172
2173 ret = split_leaf(trans, root, &orig_key, path, 0, 0);
2174 BUG_ON(ret);
2175
2176 BUG_ON(btrfs_leaf_free_space(root, leaf) < sizeof(struct btrfs_item));
2177 leaf = path->nodes[0];
2178
2179 split:
2180 item = btrfs_item_nr(leaf, path->slots[0]);
2181 orig_offset = btrfs_item_offset(leaf, item);
2182 item_size = btrfs_item_size(leaf, item);
2183
2184
2185 buf = kmalloc(item_size, GFP_NOFS);
2186 read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf,
2187 path->slots[0]), item_size);
2188 slot = path->slots[0] + 1;
2189 leaf = path->nodes[0];
2190
2191 nritems = btrfs_header_nritems(leaf);
2192
2193 if (slot != nritems) {
2194 /* shift the items */
2195 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1),
2196 btrfs_item_nr_offset(slot),
2197 (nritems - slot) * sizeof(struct btrfs_item));
2198
2199 }
2200
2201 btrfs_cpu_key_to_disk(&disk_key, new_key);
2202 btrfs_set_item_key(leaf, &disk_key, slot);
2203
2204 new_item = btrfs_item_nr(leaf, slot);
2205
2206 btrfs_set_item_offset(leaf, new_item, orig_offset);
2207 btrfs_set_item_size(leaf, new_item, item_size - split_offset);
2208
2209 btrfs_set_item_offset(leaf, item,
2210 orig_offset + item_size - split_offset);
2211 btrfs_set_item_size(leaf, item, split_offset);
2212
2213 btrfs_set_header_nritems(leaf, nritems + 1);
2214
2215 /* write the data for the start of the original item */
2216 write_extent_buffer(leaf, buf,
2217 btrfs_item_ptr_offset(leaf, path->slots[0]),
2218 split_offset);
2219
2220 /* write the data for the new item */
2221 write_extent_buffer(leaf, buf + split_offset,
2222 btrfs_item_ptr_offset(leaf, slot),
2223 item_size - split_offset);
2224 btrfs_mark_buffer_dirty(leaf);
2225
2226 ret = 0;
2227 if (btrfs_leaf_free_space(root, leaf) < 0) {
2228 btrfs_print_leaf(root, leaf);
2229 BUG();
2230 }
2231 kfree(buf);
2232 return ret;
2233 }
2234
2235 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
2236 struct btrfs_root *root,
2237 struct btrfs_path *path,
2238 u32 new_size, int from_end)
2239 {
2240 int ret = 0;
2241 int slot;
2242 int slot_orig;
2243 struct extent_buffer *leaf;
2244 struct btrfs_item *item;
2245 u32 nritems;
2246 unsigned int data_end;
2247 unsigned int old_data_start;
2248 unsigned int old_size;
2249 unsigned int size_diff;
2250 int i;
2251
2252 slot_orig = path->slots[0];
2253 leaf = path->nodes[0];
2254 slot = path->slots[0];
2255
2256 old_size = btrfs_item_size_nr(leaf, slot);
2257 if (old_size == new_size)
2258 return 0;
2259
2260 nritems = btrfs_header_nritems(leaf);
2261 data_end = leaf_data_end(root, leaf);
2262
2263 old_data_start = btrfs_item_offset_nr(leaf, slot);
2264
2265 size_diff = old_size - new_size;
2266
2267 BUG_ON(slot < 0);
2268 BUG_ON(slot >= nritems);
2269
2270 /*
2271 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2272 */
2273 /* first correct the data pointers */
2274 for (i = slot; i < nritems; i++) {
2275 u32 ioff;
2276 item = btrfs_item_nr(leaf, i);
2277 ioff = btrfs_item_offset(leaf, item);
2278 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2279 }
2280
2281 /* shift the data */
2282 if (from_end) {
2283 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2284 data_end + size_diff, btrfs_leaf_data(leaf) +
2285 data_end, old_data_start + new_size - data_end);
2286 } else {
2287 struct btrfs_disk_key disk_key;
2288 u64 offset;
2289
2290 btrfs_item_key(leaf, &disk_key, slot);
2291
2292 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2293 unsigned long ptr;
2294 struct btrfs_file_extent_item *fi;
2295
2296 fi = btrfs_item_ptr(leaf, slot,
2297 struct btrfs_file_extent_item);
2298 fi = (struct btrfs_file_extent_item *)(
2299 (unsigned long)fi - size_diff);
2300
2301 if (btrfs_file_extent_type(leaf, fi) ==
2302 BTRFS_FILE_EXTENT_INLINE) {
2303 ptr = btrfs_item_ptr_offset(leaf, slot);
2304 memmove_extent_buffer(leaf, ptr,
2305 (unsigned long)fi,
2306 offsetof(struct btrfs_file_extent_item,
2307 disk_bytenr));
2308 }
2309 }
2310
2311 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2312 data_end + size_diff, btrfs_leaf_data(leaf) +
2313 data_end, old_data_start - data_end);
2314
2315 offset = btrfs_disk_key_offset(&disk_key);
2316 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2317 btrfs_set_item_key(leaf, &disk_key, slot);
2318 if (slot == 0)
2319 fixup_low_keys(trans, root, path, &disk_key, 1);
2320 }
2321
2322 item = btrfs_item_nr(leaf, slot);
2323 btrfs_set_item_size(leaf, item, new_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 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2335 struct btrfs_root *root, struct btrfs_path *path,
2336 u32 data_size)
2337 {
2338 int ret = 0;
2339 int slot;
2340 int slot_orig;
2341 struct extent_buffer *leaf;
2342 struct btrfs_item *item;
2343 u32 nritems;
2344 unsigned int data_end;
2345 unsigned int old_data;
2346 unsigned int old_size;
2347 int i;
2348
2349 slot_orig = path->slots[0];
2350 leaf = path->nodes[0];
2351
2352 nritems = btrfs_header_nritems(leaf);
2353 data_end = leaf_data_end(root, leaf);
2354
2355 if (btrfs_leaf_free_space(root, leaf) < data_size) {
2356 btrfs_print_leaf(root, leaf);
2357 BUG();
2358 }
2359 slot = path->slots[0];
2360 old_data = btrfs_item_end_nr(leaf, slot);
2361
2362 BUG_ON(slot < 0);
2363 if (slot >= nritems) {
2364 btrfs_print_leaf(root, leaf);
2365 printk("slot %d too large, nritems %d\n", slot, nritems);
2366 BUG_ON(1);
2367 }
2368
2369 /*
2370 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2371 */
2372 /* first correct the data pointers */
2373 for (i = slot; i < nritems; i++) {
2374 u32 ioff;
2375 item = btrfs_item_nr(leaf, i);
2376 ioff = btrfs_item_offset(leaf, item);
2377 btrfs_set_item_offset(leaf, item, ioff - data_size);
2378 }
2379
2380 /* shift the data */
2381 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2382 data_end - data_size, btrfs_leaf_data(leaf) +
2383 data_end, old_data - data_end);
2384
2385 data_end = old_data;
2386 old_size = btrfs_item_size_nr(leaf, slot);
2387 item = btrfs_item_nr(leaf, slot);
2388 btrfs_set_item_size(leaf, item, old_size + data_size);
2389 btrfs_mark_buffer_dirty(leaf);
2390
2391 ret = 0;
2392 if (btrfs_leaf_free_space(root, leaf) < 0) {
2393 btrfs_print_leaf(root, leaf);
2394 BUG();
2395 }
2396 return ret;
2397 }
2398
2399 /*
2400 * Given a key and some data, insert an item into the tree.
2401 * This does all the path init required, making room in the tree if needed.
2402 */
2403 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
2404 struct btrfs_root *root,
2405 struct btrfs_path *path,
2406 struct btrfs_key *cpu_key, u32 *data_size,
2407 int nr)
2408 {
2409 struct extent_buffer *leaf;
2410 struct btrfs_item *item;
2411 int ret = 0;
2412 int slot;
2413 int slot_orig;
2414 int i;
2415 u32 nritems;
2416 u32 total_size = 0;
2417 u32 total_data = 0;
2418 unsigned int data_end;
2419 struct btrfs_disk_key disk_key;
2420
2421 for (i = 0; i < nr; i++) {
2422 total_data += data_size[i];
2423 }
2424
2425 /* create a root if there isn't one */
2426 if (!root->node)
2427 BUG();
2428
2429 total_size = total_data + (nr - 1) * sizeof(struct btrfs_item);
2430 ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
2431 if (ret == 0) {
2432 return -EEXIST;
2433 }
2434 if (ret < 0)
2435 goto out;
2436
2437 slot_orig = path->slots[0];
2438 leaf = path->nodes[0];
2439
2440 nritems = btrfs_header_nritems(leaf);
2441 data_end = leaf_data_end(root, leaf);
2442
2443 if (btrfs_leaf_free_space(root, leaf) <
2444 sizeof(struct btrfs_item) + total_size) {
2445 btrfs_print_leaf(root, leaf);
2446 printk("not enough freespace need %u have %d\n",
2447 total_size, btrfs_leaf_free_space(root, leaf));
2448 BUG();
2449 }
2450
2451 slot = path->slots[0];
2452 BUG_ON(slot < 0);
2453
2454 if (slot != nritems) {
2455 int i;
2456 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2457
2458 if (old_data < data_end) {
2459 btrfs_print_leaf(root, leaf);
2460 printk("slot %d old_data %d data_end %d\n",
2461 slot, old_data, data_end);
2462 BUG_ON(1);
2463 }
2464 /*
2465 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2466 */
2467 /* first correct the data pointers */
2468 for (i = slot; i < nritems; i++) {
2469 u32 ioff;
2470
2471 item = btrfs_item_nr(leaf, i);
2472 ioff = btrfs_item_offset(leaf, item);
2473 btrfs_set_item_offset(leaf, item, ioff - total_data);
2474 }
2475
2476 /* shift the items */
2477 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
2478 btrfs_item_nr_offset(slot),
2479 (nritems - slot) * sizeof(struct btrfs_item));
2480
2481 /* shift the data */
2482 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2483 data_end - total_data, btrfs_leaf_data(leaf) +
2484 data_end, old_data - data_end);
2485 data_end = old_data;
2486 }
2487
2488 /* setup the item for the new data */
2489 for (i = 0; i < nr; i++) {
2490 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
2491 btrfs_set_item_key(leaf, &disk_key, slot + i);
2492 item = btrfs_item_nr(leaf, slot + i);
2493 btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
2494 data_end -= data_size[i];
2495 btrfs_set_item_size(leaf, item, data_size[i]);
2496 }
2497 btrfs_set_header_nritems(leaf, nritems + nr);
2498 btrfs_mark_buffer_dirty(leaf);
2499
2500 ret = 0;
2501 if (slot == 0) {
2502 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2503 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2504 }
2505
2506 if (btrfs_leaf_free_space(root, leaf) < 0) {
2507 btrfs_print_leaf(root, leaf);
2508 BUG();
2509 }
2510
2511 out:
2512 return ret;
2513 }
2514
2515 /*
2516 * Given a key and some data, insert an item into the tree.
2517 * This does all the path init required, making room in the tree if needed.
2518 */
2519 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2520 *root, struct btrfs_key *cpu_key, void *data, u32
2521 data_size)
2522 {
2523 int ret = 0;
2524 struct btrfs_path *path;
2525 struct extent_buffer *leaf;
2526 unsigned long ptr;
2527
2528 path = btrfs_alloc_path();
2529 BUG_ON(!path);
2530 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2531 if (!ret) {
2532 leaf = path->nodes[0];
2533 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2534 write_extent_buffer(leaf, data, ptr, data_size);
2535 btrfs_mark_buffer_dirty(leaf);
2536 }
2537 btrfs_free_path(path);
2538 return ret;
2539 }
2540
2541 /*
2542 * delete the pointer from a given node.
2543 *
2544 * If the delete empties a node, the node is removed from the tree,
2545 * continuing all the way the root if required. The root is converted into
2546 * a leaf if all the nodes are emptied.
2547 */
2548 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2549 struct btrfs_path *path, int level, int slot)
2550 {
2551 struct extent_buffer *parent = path->nodes[level];
2552 u32 nritems;
2553 int ret = 0;
2554 int wret;
2555
2556 nritems = btrfs_header_nritems(parent);
2557 if (slot != nritems -1) {
2558 memmove_extent_buffer(parent,
2559 btrfs_node_key_ptr_offset(slot),
2560 btrfs_node_key_ptr_offset(slot + 1),
2561 sizeof(struct btrfs_key_ptr) *
2562 (nritems - slot - 1));
2563 }
2564 nritems--;
2565 btrfs_set_header_nritems(parent, nritems);
2566 if (nritems == 0 && parent == root->node) {
2567 BUG_ON(btrfs_header_level(root->node) != 1);
2568 /* just turn the root into a leaf and break */
2569 btrfs_set_header_level(root->node, 0);
2570 } else if (slot == 0) {
2571 struct btrfs_disk_key disk_key;
2572
2573 btrfs_node_key(parent, &disk_key, 0);
2574 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2575 if (wret)
2576 ret = wret;
2577 }
2578 btrfs_mark_buffer_dirty(parent);
2579 return ret;
2580 }
2581
2582 /*
2583 * delete the item at the leaf level in path. If that empties
2584 * the leaf, remove it from the tree
2585 */
2586 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2587 struct btrfs_path *path, int slot, int nr)
2588 {
2589 struct extent_buffer *leaf;
2590 struct btrfs_item *item;
2591 int last_off;
2592 int dsize = 0;
2593 int ret = 0;
2594 int wret;
2595 int i;
2596 u32 nritems;
2597
2598 leaf = path->nodes[0];
2599 last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
2600
2601 for (i = 0; i < nr; i++)
2602 dsize += btrfs_item_size_nr(leaf, slot + i);
2603
2604 nritems = btrfs_header_nritems(leaf);
2605
2606 if (slot + nr != nritems) {
2607 int i;
2608 int data_end = leaf_data_end(root, leaf);
2609
2610 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2611 data_end + dsize,
2612 btrfs_leaf_data(leaf) + data_end,
2613 last_off - data_end);
2614
2615 for (i = slot + nr; i < nritems; i++) {
2616 u32 ioff;
2617
2618 item = btrfs_item_nr(leaf, i);
2619 ioff = btrfs_item_offset(leaf, item);
2620 btrfs_set_item_offset(leaf, item, ioff + dsize);
2621 }
2622
2623 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2624 btrfs_item_nr_offset(slot + nr),
2625 sizeof(struct btrfs_item) *
2626 (nritems - slot - nr));
2627 }
2628 btrfs_set_header_nritems(leaf, nritems - nr);
2629 nritems -= nr;
2630
2631 /* delete the leaf if we've emptied it */
2632 if (nritems == 0) {
2633 if (leaf == root->node) {
2634 btrfs_set_header_level(leaf, 0);
2635 } else {
2636 u64 root_gen = btrfs_header_generation(path->nodes[1]);
2637 clean_tree_block(trans, root, leaf);
2638 wait_on_tree_block_writeback(root, leaf);
2639 wret = del_ptr(trans, root, path, 1, path->slots[1]);
2640 if (wret)
2641 ret = wret;
2642 wret = btrfs_free_extent(trans, root,
2643 leaf->start, leaf->len,
2644 path->nodes[1]->start,
2645 btrfs_header_owner(path->nodes[1]),
2646 root_gen, 0, 1);
2647 if (wret)
2648 ret = wret;
2649 }
2650 } else {
2651 int used = leaf_space_used(leaf, 0, nritems);
2652 if (slot == 0) {
2653 struct btrfs_disk_key disk_key;
2654
2655 btrfs_item_key(leaf, &disk_key, 0);
2656 wret = fixup_low_keys(trans, root, path,
2657 &disk_key, 1);
2658 if (wret)
2659 ret = wret;
2660 }
2661
2662 /* delete the leaf if it is mostly empty */
2663 if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
2664 /* push_leaf_left fixes the path.
2665 * make sure the path still points to our leaf
2666 * for possible call to del_ptr below
2667 */
2668 slot = path->slots[1];
2669 extent_buffer_get(leaf);
2670
2671 wret = push_leaf_left(trans, root, path, 1, 1);
2672 if (wret < 0 && wret != -ENOSPC)
2673 ret = wret;
2674
2675 if (path->nodes[0] == leaf &&
2676 btrfs_header_nritems(leaf)) {
2677 wret = push_leaf_right(trans, root, path, 1, 1);
2678 if (wret < 0 && wret != -ENOSPC)
2679 ret = wret;
2680 }
2681
2682 if (btrfs_header_nritems(leaf) == 0) {
2683 u64 root_gen;
2684 u64 bytenr = leaf->start;
2685 u32 blocksize = leaf->len;
2686
2687 root_gen = btrfs_header_generation(
2688 path->nodes[1]);
2689
2690 clean_tree_block(trans, root, leaf);
2691 wait_on_tree_block_writeback(root, leaf);
2692
2693 wret = del_ptr(trans, root, path, 1, slot);
2694 if (wret)
2695 ret = wret;
2696
2697 free_extent_buffer(leaf);
2698 wret = btrfs_free_extent(trans, root, bytenr,
2699 blocksize, path->nodes[1]->start,
2700 btrfs_header_owner(path->nodes[1]),
2701 root_gen, 0, 1);
2702 if (wret)
2703 ret = wret;
2704 } else {
2705 btrfs_mark_buffer_dirty(leaf);
2706 free_extent_buffer(leaf);
2707 }
2708 } else {
2709 btrfs_mark_buffer_dirty(leaf);
2710 }
2711 }
2712 return ret;
2713 }
2714
2715 /*
2716 * walk up the tree as far as required to find the previous leaf.
2717 * returns 0 if it found something or 1 if there are no lesser leaves.
2718 * returns < 0 on io errors.
2719 */
2720 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
2721 {
2722 int slot;
2723 int level = 1;
2724 struct extent_buffer *c;
2725 struct extent_buffer *next = NULL;
2726
2727 while(level < BTRFS_MAX_LEVEL) {
2728 if (!path->nodes[level])
2729 return 1;
2730
2731 slot = path->slots[level];
2732 c = path->nodes[level];
2733 if (slot == 0) {
2734 level++;
2735 if (level == BTRFS_MAX_LEVEL)
2736 return 1;
2737 continue;
2738 }
2739 slot--;
2740
2741 if (next)
2742 free_extent_buffer(next);
2743
2744 next = read_node_slot(root, c, slot);
2745 break;
2746 }
2747 path->slots[level] = slot;
2748 while(1) {
2749 level--;
2750 c = path->nodes[level];
2751 free_extent_buffer(c);
2752 slot = btrfs_header_nritems(next);
2753 if (slot != 0)
2754 slot--;
2755 path->nodes[level] = next;
2756 path->slots[level] = slot;
2757 if (!level)
2758 break;
2759 next = read_node_slot(root, next, slot);
2760 }
2761 return 0;
2762 }
2763
2764 /*
2765 * walk up the tree as far as required to find the next leaf.
2766 * returns 0 if it found something or 1 if there are no greater leaves.
2767 * returns < 0 on io errors.
2768 */
2769 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2770 {
2771 int slot;
2772 int level = 1;
2773 struct extent_buffer *c;
2774 struct extent_buffer *next = NULL;
2775
2776 while(level < BTRFS_MAX_LEVEL) {
2777 if (!path->nodes[level])
2778 return 1;
2779
2780 slot = path->slots[level] + 1;
2781 c = path->nodes[level];
2782 if (slot >= btrfs_header_nritems(c)) {
2783 level++;
2784 if (level == BTRFS_MAX_LEVEL)
2785 return 1;
2786 continue;
2787 }
2788
2789 if (next)
2790 free_extent_buffer(next);
2791
2792 if (path->reada)
2793 reada_for_search(root, path, level, slot, 0);
2794
2795 next = read_node_slot(root, c, slot);
2796 break;
2797 }
2798 path->slots[level] = slot;
2799 while(1) {
2800 level--;
2801 c = path->nodes[level];
2802 free_extent_buffer(c);
2803 path->nodes[level] = next;
2804 path->slots[level] = 0;
2805 if (!level)
2806 break;
2807 if (path->reada)
2808 reada_for_search(root, path, level, 0, 0);
2809 next = read_node_slot(root, next, 0);
2810 }
2811 return 0;
2812 }
2813
2814 int btrfs_previous_item(struct btrfs_root *root,
2815 struct btrfs_path *path, u64 min_objectid,
2816 int type)
2817 {
2818 struct btrfs_key found_key;
2819 struct extent_buffer *leaf;
2820 int ret;
2821
2822 while(1) {
2823 if (path->slots[0] == 0) {
2824 ret = btrfs_prev_leaf(root, path);
2825 if (ret != 0)
2826 return ret;
2827 } else {
2828 path->slots[0]--;
2829 }
2830 leaf = path->nodes[0];
2831 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2832 if (found_key.type == type)
2833 return 0;
2834 }
2835 return 1;
2836 }
2837
(deprecated) Btrfs progs developments and patch integration