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Btrfs: Fix balance_level to free the middle block if there is room in the left one
[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, int empty);
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 /* once for the path */
755 free_extent_buffer(mid);
756 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
757 root->root_key.objectid,
758 btrfs_header_generation(mid), 0, 0, 1);
759 /* once for the root ptr */
760 free_extent_buffer(mid);
761 return ret;
762 }
763 if (btrfs_header_nritems(mid) >
764 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
765 return 0;
766
767 if (btrfs_header_nritems(mid) < 2)
768 err_on_enospc = 1;
769
770 left = read_node_slot(root, parent, pslot - 1);
771 if (left) {
772 wret = btrfs_cow_block(trans, root, left,
773 parent, pslot - 1, &left);
774 if (wret) {
775 ret = wret;
776 goto enospc;
777 }
778 }
779 right = read_node_slot(root, parent, pslot + 1);
780 if (right) {
781 wret = btrfs_cow_block(trans, root, right,
782 parent, pslot + 1, &right);
783 if (wret) {
784 ret = wret;
785 goto enospc;
786 }
787 }
788
789 /* first, try to make some room in the middle buffer */
790 if (left) {
791 orig_slot += btrfs_header_nritems(left);
792 wret = push_node_left(trans, root, left, mid, 1);
793 if (wret < 0)
794 ret = wret;
795 if (btrfs_header_nritems(mid) < 2)
796 err_on_enospc = 1;
797 }
798
799 /*
800 * then try to empty the right most buffer into the middle
801 */
802 if (right) {
803 wret = push_node_left(trans, root, mid, right, 1);
804 if (wret < 0 && wret != -ENOSPC)
805 ret = wret;
806 if (btrfs_header_nritems(right) == 0) {
807 u64 bytenr = right->start;
808 u64 generation = btrfs_header_generation(parent);
809 u32 blocksize = right->len;
810
811 clean_tree_block(trans, root, right);
812 free_extent_buffer(right);
813 right = NULL;
814 wret = del_ptr(trans, root, path, level + 1, pslot +
815 1);
816 if (wret)
817 ret = wret;
818 wret = btrfs_free_extent(trans, root, bytenr,
819 blocksize,
820 btrfs_header_owner(parent),
821 generation, 0, 0, 1);
822 if (wret)
823 ret = wret;
824 } else {
825 struct btrfs_disk_key right_key;
826 btrfs_node_key(right, &right_key, 0);
827 btrfs_set_node_key(parent, &right_key, pslot + 1);
828 btrfs_mark_buffer_dirty(parent);
829 }
830 }
831 if (btrfs_header_nritems(mid) == 1) {
832 /*
833 * we're not allowed to leave a node with one item in the
834 * tree during a delete. A deletion from lower in the tree
835 * could try to delete the only pointer in this node.
836 * So, pull some keys from the left.
837 * There has to be a left pointer at this point because
838 * otherwise we would have pulled some pointers from the
839 * right
840 */
841 BUG_ON(!left);
842 wret = balance_node_right(trans, root, mid, left);
843 if (wret < 0) {
844 ret = wret;
845 goto enospc;
846 }
847 if (wret == 1) {
848 wret = push_node_left(trans, root, left, mid, 1);
849 if (wret < 0)
850 ret = wret;
851 }
852 BUG_ON(wret == 1);
853 }
854 if (btrfs_header_nritems(mid) == 0) {
855 /* we've managed to empty the middle node, drop it */
856 u64 root_gen = btrfs_header_generation(parent);
857 u64 bytenr = mid->start;
858 u32 blocksize = mid->len;
859 clean_tree_block(trans, root, mid);
860 free_extent_buffer(mid);
861 mid = NULL;
862 wret = del_ptr(trans, root, path, level + 1, pslot);
863 if (wret)
864 ret = wret;
865 wret = btrfs_free_extent(trans, root, bytenr, blocksize,
866 btrfs_header_owner(parent),
867 root_gen, 0, 0, 1);
868 if (wret)
869 ret = wret;
870 } else {
871 /* update the parent key to reflect our changes */
872 struct btrfs_disk_key mid_key;
873 btrfs_node_key(mid, &mid_key, 0);
874 btrfs_set_node_key(parent, &mid_key, pslot);
875 btrfs_mark_buffer_dirty(parent);
876 }
877
878 /* update the path */
879 if (left) {
880 if (btrfs_header_nritems(left) > orig_slot) {
881 extent_buffer_get(left);
882 path->nodes[level] = left;
883 path->slots[level + 1] -= 1;
884 path->slots[level] = orig_slot;
885 if (mid)
886 free_extent_buffer(mid);
887 } else {
888 orig_slot -= btrfs_header_nritems(left);
889 path->slots[level] = orig_slot;
890 }
891 }
892 /* double check we haven't messed things up */
893 check_block(root, path, level);
894 if (orig_ptr !=
895 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
896 BUG();
897 enospc:
898 if (right)
899 free_extent_buffer(right);
900 if (left)
901 free_extent_buffer(left);
902 return ret;
903 }
904
905 /* returns zero if the push worked, non-zero otherwise */
906 static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
907 struct btrfs_root *root,
908 struct btrfs_path *path, int level)
909 {
910 struct extent_buffer *right = NULL;
911 struct extent_buffer *mid;
912 struct extent_buffer *left = NULL;
913 struct extent_buffer *parent = NULL;
914 int ret = 0;
915 int wret;
916 int pslot;
917 int orig_slot = path->slots[level];
918 u64 orig_ptr;
919
920 if (level == 0)
921 return 1;
922
923 mid = path->nodes[level];
924 WARN_ON(btrfs_header_generation(mid) != trans->transid);
925 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
926
927 if (level < BTRFS_MAX_LEVEL - 1)
928 parent = path->nodes[level + 1];
929 pslot = path->slots[level + 1];
930
931 if (!parent)
932 return 1;
933
934 left = read_node_slot(root, parent, pslot - 1);
935
936 /* first, try to make some room in the middle buffer */
937 if (left) {
938 u32 left_nr;
939 left_nr = btrfs_header_nritems(left);
940 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
941 wret = 1;
942 } else {
943 ret = btrfs_cow_block(trans, root, left, parent,
944 pslot - 1, &left);
945 if (ret)
946 wret = 1;
947 else {
948 wret = push_node_left(trans, root,
949 left, mid, 0);
950 }
951 }
952 if (wret < 0)
953 ret = wret;
954 if (wret == 0) {
955 struct btrfs_disk_key disk_key;
956 orig_slot += left_nr;
957 btrfs_node_key(mid, &disk_key, 0);
958 btrfs_set_node_key(parent, &disk_key, pslot);
959 btrfs_mark_buffer_dirty(parent);
960 if (btrfs_header_nritems(left) > orig_slot) {
961 path->nodes[level] = left;
962 path->slots[level + 1] -= 1;
963 path->slots[level] = orig_slot;
964 free_extent_buffer(mid);
965 } else {
966 orig_slot -=
967 btrfs_header_nritems(left);
968 path->slots[level] = orig_slot;
969 free_extent_buffer(left);
970 }
971 return 0;
972 }
973 free_extent_buffer(left);
974 }
975 right= read_node_slot(root, parent, pslot + 1);
976
977 /*
978 * then try to empty the right most buffer into the middle
979 */
980 if (right) {
981 u32 right_nr;
982 right_nr = btrfs_header_nritems(right);
983 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
984 wret = 1;
985 } else {
986 ret = btrfs_cow_block(trans, root, right,
987 parent, pslot + 1,
988 &right);
989 if (ret)
990 wret = 1;
991 else {
992 wret = balance_node_right(trans, root,
993 right, mid);
994 }
995 }
996 if (wret < 0)
997 ret = wret;
998 if (wret == 0) {
999 struct btrfs_disk_key disk_key;
1000
1001 btrfs_node_key(right, &disk_key, 0);
1002 btrfs_set_node_key(parent, &disk_key, pslot + 1);
1003 btrfs_mark_buffer_dirty(parent);
1004
1005 if (btrfs_header_nritems(mid) <= orig_slot) {
1006 path->nodes[level] = right;
1007 path->slots[level + 1] += 1;
1008 path->slots[level] = orig_slot -
1009 btrfs_header_nritems(mid);
1010 free_extent_buffer(mid);
1011 } else {
1012 free_extent_buffer(right);
1013 }
1014 return 0;
1015 }
1016 free_extent_buffer(right);
1017 }
1018 return 1;
1019 }
1020
1021 /*
1022 * readahead one full node of leaves
1023 */
1024 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
1025 int level, int slot, u64 objectid)
1026 {
1027 struct extent_buffer *node;
1028 struct btrfs_disk_key disk_key;
1029 u32 nritems;
1030 u64 search;
1031 u64 lowest_read;
1032 u64 highest_read;
1033 u64 nread = 0;
1034 int direction = path->reada;
1035 struct extent_buffer *eb;
1036 u32 nr;
1037 u32 blocksize;
1038 u32 nscan = 0;
1039
1040 if (level != 1)
1041 return;
1042
1043 if (!path->nodes[level])
1044 return;
1045
1046 node = path->nodes[level];
1047 search = btrfs_node_blockptr(node, slot);
1048 blocksize = btrfs_level_size(root, level - 1);
1049 eb = btrfs_find_tree_block(root, search, blocksize);
1050 if (eb) {
1051 free_extent_buffer(eb);
1052 return;
1053 }
1054
1055 highest_read = search;
1056 lowest_read = search;
1057
1058 nritems = btrfs_header_nritems(node);
1059 nr = slot;
1060 while(1) {
1061 if (direction < 0) {
1062 if (nr == 0)
1063 break;
1064 nr--;
1065 } else if (direction > 0) {
1066 nr++;
1067 if (nr >= nritems)
1068 break;
1069 }
1070 if (path->reada < 0 && objectid) {
1071 btrfs_node_key(node, &disk_key, nr);
1072 if (btrfs_disk_key_objectid(&disk_key) != objectid)
1073 break;
1074 }
1075 search = btrfs_node_blockptr(node, nr);
1076 if ((search >= lowest_read && search <= highest_read) ||
1077 (search < lowest_read && lowest_read - search <= 32768) ||
1078 (search > highest_read && search - highest_read <= 32768)) {
1079 readahead_tree_block(root, search, blocksize);
1080 nread += blocksize;
1081 }
1082 nscan++;
1083 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
1084 break;
1085 if(nread > (1024 * 1024) || nscan > 128)
1086 break;
1087
1088 if (search < lowest_read)
1089 lowest_read = search;
1090 if (search > highest_read)
1091 highest_read = search;
1092 }
1093 }
1094 /*
1095 * look for key in the tree. path is filled in with nodes along the way
1096 * if key is found, we return zero and you can find the item in the leaf
1097 * level of the path (level 0)
1098 *
1099 * If the key isn't found, the path points to the slot where it should
1100 * be inserted, and 1 is returned. If there are other errors during the
1101 * search a negative error number is returned.
1102 *
1103 * if ins_len > 0, nodes and leaves will be split as we walk down the
1104 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
1105 * possible)
1106 */
1107 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
1108 *root, struct btrfs_key *key, struct btrfs_path *p, int
1109 ins_len, int cow)
1110 {
1111 struct extent_buffer *b;
1112 u64 bytenr;
1113 u64 ptr_gen;
1114 int slot;
1115 int ret;
1116 int level;
1117 int should_reada = p->reada;
1118 u8 lowest_level = 0;
1119
1120 lowest_level = p->lowest_level;
1121 WARN_ON(lowest_level && ins_len);
1122 WARN_ON(p->nodes[0] != NULL);
1123 WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
1124 again:
1125 b = root->node;
1126 extent_buffer_get(b);
1127 while (b) {
1128 level = btrfs_header_level(b);
1129 if (cow) {
1130 int wret;
1131 wret = btrfs_cow_block(trans, root, b,
1132 p->nodes[level + 1],
1133 p->slots[level + 1],
1134 &b);
1135 if (wret) {
1136 free_extent_buffer(b);
1137 return wret;
1138 }
1139 }
1140 BUG_ON(!cow && ins_len);
1141 if (level != btrfs_header_level(b))
1142 WARN_ON(1);
1143 level = btrfs_header_level(b);
1144 p->nodes[level] = b;
1145 ret = check_block(root, p, level);
1146 if (ret)
1147 return -1;
1148 ret = bin_search(b, key, level, &slot);
1149 if (level != 0) {
1150 if (ret && slot > 0)
1151 slot -= 1;
1152 p->slots[level] = slot;
1153 if (ins_len > 0 && btrfs_header_nritems(b) >=
1154 BTRFS_NODEPTRS_PER_BLOCK(root) - 3) {
1155 int sret = split_node(trans, root, p, level);
1156 BUG_ON(sret > 0);
1157 if (sret)
1158 return sret;
1159 b = p->nodes[level];
1160 slot = p->slots[level];
1161 } else if (ins_len < 0) {
1162 int sret = balance_level(trans, root, p,
1163 level);
1164 if (sret)
1165 return sret;
1166 b = p->nodes[level];
1167 if (!b) {
1168 btrfs_release_path(NULL, p);
1169 goto again;
1170 }
1171 slot = p->slots[level];
1172 BUG_ON(btrfs_header_nritems(b) == 1);
1173 }
1174 /* this is only true while dropping a snapshot */
1175 if (level == lowest_level)
1176 break;
1177 bytenr = btrfs_node_blockptr(b, slot);
1178 ptr_gen = btrfs_node_ptr_generation(b, slot);
1179 if (should_reada)
1180 reada_for_search(root, p, level, slot,
1181 key->objectid);
1182 b = read_tree_block(root, bytenr,
1183 btrfs_level_size(root, level - 1));
1184 if (ptr_gen != btrfs_header_generation(b)) {
1185 printk("block %llu bad gen wanted %llu "
1186 "found %llu\n",
1187 (unsigned long long)b->start,
1188 (unsigned long long)ptr_gen,
1189 (unsigned long long)btrfs_header_generation(b));
1190 }
1191 } else {
1192 p->slots[level] = slot;
1193 if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1194 sizeof(struct btrfs_item) + ins_len) {
1195 int sret = split_leaf(trans, root, key,
1196 p, ins_len, ret == 0);
1197 BUG_ON(sret > 0);
1198 if (sret)
1199 return sret;
1200 }
1201 return ret;
1202 }
1203 }
1204 return 1;
1205 }
1206
1207 /*
1208 * adjust the pointers going up the tree, starting at level
1209 * making sure the right key of each node is points to 'key'.
1210 * This is used after shifting pointers to the left, so it stops
1211 * fixing up pointers when a given leaf/node is not in slot 0 of the
1212 * higher levels
1213 *
1214 * If this fails to write a tree block, it returns -1, but continues
1215 * fixing up the blocks in ram so the tree is consistent.
1216 */
1217 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1218 struct btrfs_root *root, struct btrfs_path *path,
1219 struct btrfs_disk_key *key, int level)
1220 {
1221 int i;
1222 int ret = 0;
1223 struct extent_buffer *t;
1224
1225 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1226 int tslot = path->slots[i];
1227 if (!path->nodes[i])
1228 break;
1229 t = path->nodes[i];
1230 btrfs_set_node_key(t, key, tslot);
1231 btrfs_mark_buffer_dirty(path->nodes[i]);
1232 if (tslot != 0)
1233 break;
1234 }
1235 return ret;
1236 }
1237
1238 /*
1239 * try to push data from one node into the next node left in the
1240 * tree.
1241 *
1242 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1243 * error, and > 0 if there was no room in the left hand block.
1244 */
1245 static int push_node_left(struct btrfs_trans_handle *trans,
1246 struct btrfs_root *root, struct extent_buffer *dst,
1247 struct extent_buffer *src, int empty)
1248 {
1249 int push_items = 0;
1250 int src_nritems;
1251 int dst_nritems;
1252 int ret = 0;
1253
1254 src_nritems = btrfs_header_nritems(src);
1255 dst_nritems = btrfs_header_nritems(dst);
1256 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1257 WARN_ON(btrfs_header_generation(src) != trans->transid);
1258 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1259
1260 if (!empty && src_nritems <= 8)
1261 return 1;
1262
1263 if (push_items <= 0) {
1264 return 1;
1265 }
1266
1267 if (empty) {
1268 push_items = min(src_nritems, push_items);
1269 if (push_items < src_nritems) {
1270 /* leave at least 8 pointers in the node if
1271 * we aren't going to empty it
1272 */
1273 if (src_nritems - push_items < 8) {
1274 if (push_items <= 8)
1275 return 1;
1276 push_items -= 8;
1277 }
1278 }
1279 } else
1280 push_items = min(src_nritems - 8, push_items);
1281
1282 copy_extent_buffer(dst, src,
1283 btrfs_node_key_ptr_offset(dst_nritems),
1284 btrfs_node_key_ptr_offset(0),
1285 push_items * sizeof(struct btrfs_key_ptr));
1286
1287 if (push_items < src_nritems) {
1288 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1289 btrfs_node_key_ptr_offset(push_items),
1290 (src_nritems - push_items) *
1291 sizeof(struct btrfs_key_ptr));
1292 }
1293 btrfs_set_header_nritems(src, src_nritems - push_items);
1294 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1295 btrfs_mark_buffer_dirty(src);
1296 btrfs_mark_buffer_dirty(dst);
1297 return ret;
1298 }
1299
1300 /*
1301 * try to push data from one node into the next node right in the
1302 * tree.
1303 *
1304 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1305 * error, and > 0 if there was no room in the right hand block.
1306 *
1307 * this will only push up to 1/2 the contents of the left node over
1308 */
1309 static int balance_node_right(struct btrfs_trans_handle *trans,
1310 struct btrfs_root *root,
1311 struct extent_buffer *dst,
1312 struct extent_buffer *src)
1313 {
1314 int push_items = 0;
1315 int max_push;
1316 int src_nritems;
1317 int dst_nritems;
1318 int ret = 0;
1319
1320 WARN_ON(btrfs_header_generation(src) != trans->transid);
1321 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1322
1323 src_nritems = btrfs_header_nritems(src);
1324 dst_nritems = btrfs_header_nritems(dst);
1325 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1326 if (push_items <= 0) {
1327 return 1;
1328 }
1329
1330 if (src_nritems < 4) {
1331 return 1;
1332 }
1333
1334 max_push = src_nritems / 2 + 1;
1335 /* don't try to empty the node */
1336 if (max_push >= src_nritems) {
1337 return 1;
1338 }
1339
1340 if (max_push < push_items)
1341 push_items = max_push;
1342
1343 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1344 btrfs_node_key_ptr_offset(0),
1345 (dst_nritems) *
1346 sizeof(struct btrfs_key_ptr));
1347
1348 copy_extent_buffer(dst, src,
1349 btrfs_node_key_ptr_offset(0),
1350 btrfs_node_key_ptr_offset(src_nritems - push_items),
1351 push_items * sizeof(struct btrfs_key_ptr));
1352
1353 btrfs_set_header_nritems(src, src_nritems - push_items);
1354 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1355
1356 btrfs_mark_buffer_dirty(src);
1357 btrfs_mark_buffer_dirty(dst);
1358 return ret;
1359 }
1360
1361 /*
1362 * helper function to insert a new root level in the tree.
1363 * A new node is allocated, and a single item is inserted to
1364 * point to the existing root
1365 *
1366 * returns zero on success or < 0 on failure.
1367 */
1368 static int noinline insert_new_root(struct btrfs_trans_handle *trans,
1369 struct btrfs_root *root,
1370 struct btrfs_path *path, int level)
1371 {
1372 u64 root_gen;
1373 u64 lower_gen;
1374 struct extent_buffer *lower;
1375 struct extent_buffer *c;
1376 struct btrfs_disk_key lower_key;
1377
1378 BUG_ON(path->nodes[level]);
1379 BUG_ON(path->nodes[level-1] != root->node);
1380
1381 if (root->ref_cows)
1382 root_gen = trans->transid;
1383 else
1384 root_gen = 0;
1385
1386 lower = path->nodes[level-1];
1387 if (level == 1)
1388 btrfs_item_key(lower, &lower_key, 0);
1389 else
1390 btrfs_node_key(lower, &lower_key, 0);
1391
1392 c = __btrfs_alloc_free_block(trans, root, root->nodesize,
1393 root->root_key.objectid,
1394 root_gen, lower_key.objectid, level,
1395 root->node->start, 0);
1396 if (IS_ERR(c))
1397 return PTR_ERR(c);
1398 memset_extent_buffer(c, 0, 0, root->nodesize);
1399 btrfs_set_header_nritems(c, 1);
1400 btrfs_set_header_level(c, level);
1401 btrfs_set_header_bytenr(c, c->start);
1402 btrfs_set_header_generation(c, trans->transid);
1403 btrfs_set_header_owner(c, root->root_key.objectid);
1404
1405 write_extent_buffer(c, root->fs_info->fsid,
1406 (unsigned long)btrfs_header_fsid(c),
1407 BTRFS_FSID_SIZE);
1408
1409 write_extent_buffer(c, root->fs_info->chunk_tree_uuid,
1410 (unsigned long)btrfs_header_chunk_tree_uuid(c),
1411 BTRFS_UUID_SIZE);
1412
1413 btrfs_set_node_key(c, &lower_key, 0);
1414 btrfs_set_node_blockptr(c, 0, lower->start);
1415 lower_gen = btrfs_header_generation(lower);
1416 WARN_ON(lower_gen == 0);
1417
1418 btrfs_set_node_ptr_generation(c, 0, lower_gen);
1419
1420 btrfs_mark_buffer_dirty(c);
1421
1422 /* the super has an extra ref to root->node */
1423 free_extent_buffer(root->node);
1424 root->node = c;
1425 add_root_to_dirty_list(root);
1426 extent_buffer_get(c);
1427 path->nodes[level] = c;
1428 path->slots[level] = 0;
1429
1430 if (root->ref_cows && lower_gen != trans->transid) {
1431 struct btrfs_path *back_path = btrfs_alloc_path();
1432 int ret;
1433 ret = btrfs_insert_extent_backref(trans,
1434 root->fs_info->extent_root,
1435 path, lower->start,
1436 root->root_key.objectid,
1437 trans->transid, 0, 0);
1438 BUG_ON(ret);
1439 btrfs_free_path(back_path);
1440 }
1441 return 0;
1442 }
1443
1444 /*
1445 * worker function to insert a single pointer in a node.
1446 * the node should have enough room for the pointer already
1447 *
1448 * slot and level indicate where you want the key to go, and
1449 * blocknr is the block the key points to.
1450 *
1451 * returns zero on success and < 0 on any error
1452 */
1453 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1454 *root, struct btrfs_path *path, struct btrfs_disk_key
1455 *key, u64 bytenr, int slot, int level)
1456 {
1457 struct extent_buffer *lower;
1458 int nritems;
1459
1460 BUG_ON(!path->nodes[level]);
1461 lower = path->nodes[level];
1462 nritems = btrfs_header_nritems(lower);
1463 if (slot > nritems)
1464 BUG();
1465 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1466 BUG();
1467 if (slot != nritems) {
1468 memmove_extent_buffer(lower,
1469 btrfs_node_key_ptr_offset(slot + 1),
1470 btrfs_node_key_ptr_offset(slot),
1471 (nritems - slot) * sizeof(struct btrfs_key_ptr));
1472 }
1473 btrfs_set_node_key(lower, key, slot);
1474 btrfs_set_node_blockptr(lower, slot, bytenr);
1475 WARN_ON(trans->transid == 0);
1476 btrfs_set_node_ptr_generation(lower, slot, trans->transid);
1477 btrfs_set_header_nritems(lower, nritems + 1);
1478 btrfs_mark_buffer_dirty(lower);
1479 return 0;
1480 }
1481
1482 /*
1483 * split the node at the specified level in path in two.
1484 * The path is corrected to point to the appropriate node after the split
1485 *
1486 * Before splitting this tries to make some room in the node by pushing
1487 * left and right, if either one works, it returns right away.
1488 *
1489 * returns 0 on success and < 0 on failure
1490 */
1491 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1492 *root, struct btrfs_path *path, int level)
1493 {
1494 u64 root_gen;
1495 struct extent_buffer *c;
1496 struct extent_buffer *split;
1497 struct btrfs_disk_key disk_key;
1498 int mid;
1499 int ret;
1500 int wret;
1501 u32 c_nritems;
1502
1503 c = path->nodes[level];
1504 WARN_ON(btrfs_header_generation(c) != trans->transid);
1505 if (c == root->node) {
1506 /* trying to split the root, lets make a new one */
1507 ret = insert_new_root(trans, root, path, level + 1);
1508 if (ret)
1509 return ret;
1510 } else {
1511 ret = push_nodes_for_insert(trans, root, path, level);
1512 c = path->nodes[level];
1513 if (!ret && btrfs_header_nritems(c) <
1514 BTRFS_NODEPTRS_PER_BLOCK(root) - 3)
1515 return 0;
1516 if (ret < 0)
1517 return ret;
1518 }
1519
1520 c_nritems = btrfs_header_nritems(c);
1521 if (root->ref_cows)
1522 root_gen = trans->transid;
1523 else
1524 root_gen = 0;
1525
1526 btrfs_node_key(c, &disk_key, 0);
1527 split = __btrfs_alloc_free_block(trans, root, root->nodesize,
1528 root->root_key.objectid,
1529 root_gen,
1530 btrfs_disk_key_objectid(&disk_key),
1531 level, c->start, 0);
1532 if (IS_ERR(split))
1533 return PTR_ERR(split);
1534
1535 btrfs_set_header_flags(split, btrfs_header_flags(c));
1536 btrfs_set_header_level(split, btrfs_header_level(c));
1537 btrfs_set_header_bytenr(split, split->start);
1538 btrfs_set_header_generation(split, trans->transid);
1539 btrfs_set_header_owner(split, root->root_key.objectid);
1540 btrfs_set_header_flags(split, 0);
1541 write_extent_buffer(split, root->fs_info->fsid,
1542 (unsigned long)btrfs_header_fsid(split),
1543 BTRFS_FSID_SIZE);
1544 write_extent_buffer(split, root->fs_info->chunk_tree_uuid,
1545 (unsigned long)btrfs_header_chunk_tree_uuid(split),
1546 BTRFS_UUID_SIZE);
1547
1548 mid = (c_nritems + 1) / 2;
1549
1550 copy_extent_buffer(split, c,
1551 btrfs_node_key_ptr_offset(0),
1552 btrfs_node_key_ptr_offset(mid),
1553 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1554 btrfs_set_header_nritems(split, c_nritems - mid);
1555 btrfs_set_header_nritems(c, mid);
1556 ret = 0;
1557
1558 btrfs_mark_buffer_dirty(c);
1559 btrfs_mark_buffer_dirty(split);
1560
1561 btrfs_node_key(split, &disk_key, 0);
1562 wret = insert_ptr(trans, root, path, &disk_key, split->start,
1563 path->slots[level + 1] + 1,
1564 level + 1);
1565 if (wret)
1566 ret = wret;
1567
1568 if (path->slots[level] >= mid) {
1569 path->slots[level] -= mid;
1570 free_extent_buffer(c);
1571 path->nodes[level] = split;
1572 path->slots[level + 1] += 1;
1573 } else {
1574 free_extent_buffer(split);
1575 }
1576 return ret;
1577 }
1578
1579 /*
1580 * how many bytes are required to store the items in a leaf. start
1581 * and nr indicate which items in the leaf to check. This totals up the
1582 * space used both by the item structs and the item data
1583 */
1584 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1585 {
1586 int data_len;
1587 int nritems = btrfs_header_nritems(l);
1588 int end = min(nritems, start + nr) - 1;
1589
1590 if (!nr)
1591 return 0;
1592 data_len = btrfs_item_end_nr(l, start);
1593 data_len = data_len - btrfs_item_offset_nr(l, end);
1594 data_len += sizeof(struct btrfs_item) * nr;
1595 WARN_ON(data_len < 0);
1596 return data_len;
1597 }
1598
1599 /*
1600 * The space between the end of the leaf items and
1601 * the start of the leaf data. IOW, how much room
1602 * the leaf has left for both items and data
1603 */
1604 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1605 {
1606 int nritems = btrfs_header_nritems(leaf);
1607 int ret;
1608 ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1609 if (ret < 0) {
1610 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1611 ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
1612 leaf_space_used(leaf, 0, nritems), nritems);
1613 }
1614 return ret;
1615 }
1616
1617 /*
1618 * push some data in the path leaf to the right, trying to free up at
1619 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1620 *
1621 * returns 1 if the push failed because the other node didn't have enough
1622 * room, 0 if everything worked out and < 0 if there were major errors.
1623 */
1624 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1625 *root, struct btrfs_path *path, int data_size,
1626 int empty)
1627 {
1628 struct extent_buffer *left = path->nodes[0];
1629 struct extent_buffer *right;
1630 struct extent_buffer *upper;
1631 struct btrfs_disk_key disk_key;
1632 int slot;
1633 u32 i;
1634 int free_space;
1635 int push_space = 0;
1636 int push_items = 0;
1637 struct btrfs_item *item;
1638 u32 left_nritems;
1639 u32 nr;
1640 u32 right_nritems;
1641 u32 data_end;
1642 u32 this_item_size;
1643 int ret;
1644
1645 slot = path->slots[1];
1646 if (!path->nodes[1]) {
1647 return 1;
1648 }
1649 upper = path->nodes[1];
1650 if (slot >= btrfs_header_nritems(upper) - 1)
1651 return 1;
1652
1653 right = read_tree_block(root, btrfs_node_blockptr(upper, slot + 1),
1654 root->leafsize);
1655 free_space = btrfs_leaf_free_space(root, right);
1656 if (free_space < data_size + sizeof(struct btrfs_item)) {
1657 free_extent_buffer(right);
1658 return 1;
1659 }
1660
1661 /* cow and double check */
1662 ret = btrfs_cow_block(trans, root, right, upper,
1663 slot + 1, &right);
1664 if (ret) {
1665 free_extent_buffer(right);
1666 return 1;
1667 }
1668 free_space = btrfs_leaf_free_space(root, right);
1669 if (free_space < data_size + sizeof(struct btrfs_item)) {
1670 free_extent_buffer(right);
1671 return 1;
1672 }
1673
1674 left_nritems = btrfs_header_nritems(left);
1675 if (left_nritems == 0) {
1676 free_extent_buffer(right);
1677 return 1;
1678 }
1679
1680 if (empty)
1681 nr = 0;
1682 else
1683 nr = 1;
1684
1685 i = left_nritems - 1;
1686 while (i >= nr) {
1687 item = btrfs_item_nr(left, i);
1688
1689 if (path->slots[0] == i)
1690 push_space += data_size + sizeof(*item);
1691
1692 if (!left->map_token) {
1693 map_extent_buffer(left, (unsigned long)item,
1694 sizeof(struct btrfs_item),
1695 &left->map_token, &left->kaddr,
1696 &left->map_start, &left->map_len,
1697 KM_USER1);
1698 }
1699
1700 this_item_size = btrfs_item_size(left, item);
1701 if (this_item_size + sizeof(*item) + push_space > free_space)
1702 break;
1703 push_items++;
1704 push_space += this_item_size + sizeof(*item);
1705 if (i == 0)
1706 break;
1707 i--;
1708 }
1709 if (left->map_token) {
1710 unmap_extent_buffer(left, left->map_token, KM_USER1);
1711 left->map_token = NULL;
1712 }
1713
1714 if (push_items == 0) {
1715 free_extent_buffer(right);
1716 return 1;
1717 }
1718
1719 if (!empty && push_items == left_nritems)
1720 WARN_ON(1);
1721
1722 /* push left to right */
1723 right_nritems = btrfs_header_nritems(right);
1724
1725 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1726 push_space -= leaf_data_end(root, left);
1727
1728 /* make room in the right data area */
1729 data_end = leaf_data_end(root, right);
1730 memmove_extent_buffer(right,
1731 btrfs_leaf_data(right) + data_end - push_space,
1732 btrfs_leaf_data(right) + data_end,
1733 BTRFS_LEAF_DATA_SIZE(root) - data_end);
1734
1735 /* copy from the left data area */
1736 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1737 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1738 btrfs_leaf_data(left) + leaf_data_end(root, left),
1739 push_space);
1740
1741 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1742 btrfs_item_nr_offset(0),
1743 right_nritems * sizeof(struct btrfs_item));
1744
1745 /* copy the items from left to right */
1746 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1747 btrfs_item_nr_offset(left_nritems - push_items),
1748 push_items * sizeof(struct btrfs_item));
1749
1750 /* update the item pointers */
1751 right_nritems += push_items;
1752 btrfs_set_header_nritems(right, right_nritems);
1753 push_space = BTRFS_LEAF_DATA_SIZE(root);
1754 for (i = 0; i < right_nritems; i++) {
1755 item = btrfs_item_nr(right, i);
1756 if (!right->map_token) {
1757 map_extent_buffer(right, (unsigned long)item,
1758 sizeof(struct btrfs_item),
1759 &right->map_token, &right->kaddr,
1760 &right->map_start, &right->map_len,
1761 KM_USER1);
1762 }
1763 push_space -= btrfs_item_size(right, item);
1764 btrfs_set_item_offset(right, item, push_space);
1765 }
1766
1767 if (right->map_token) {
1768 unmap_extent_buffer(right, right->map_token, KM_USER1);
1769 right->map_token = NULL;
1770 }
1771 left_nritems -= push_items;
1772 btrfs_set_header_nritems(left, left_nritems);
1773
1774 if (left_nritems)
1775 btrfs_mark_buffer_dirty(left);
1776 btrfs_mark_buffer_dirty(right);
1777
1778 btrfs_item_key(right, &disk_key, 0);
1779 btrfs_set_node_key(upper, &disk_key, slot + 1);
1780 btrfs_mark_buffer_dirty(upper);
1781
1782 /* then fixup the leaf pointer in the path */
1783 if (path->slots[0] >= left_nritems) {
1784 path->slots[0] -= left_nritems;
1785 free_extent_buffer(path->nodes[0]);
1786 path->nodes[0] = right;
1787 path->slots[1] += 1;
1788 } else {
1789 free_extent_buffer(right);
1790 }
1791 return 0;
1792 }
1793 /*
1794 * push some data in the path leaf to the left, trying to free up at
1795 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1796 */
1797 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1798 *root, struct btrfs_path *path, int data_size,
1799 int empty)
1800 {
1801 struct btrfs_disk_key disk_key;
1802 struct extent_buffer *right = path->nodes[0];
1803 struct extent_buffer *left;
1804 int slot;
1805 int i;
1806 int free_space;
1807 int push_space = 0;
1808 int push_items = 0;
1809 struct btrfs_item *item;
1810 u32 old_left_nritems;
1811 u32 right_nritems;
1812 u32 nr;
1813 int ret = 0;
1814 int wret;
1815 u32 this_item_size;
1816 u32 old_left_item_size;
1817
1818 slot = path->slots[1];
1819 if (slot == 0)
1820 return 1;
1821 if (!path->nodes[1])
1822 return 1;
1823
1824 right_nritems = btrfs_header_nritems(right);
1825 if (right_nritems == 0) {
1826 return 1;
1827 }
1828
1829 left = read_tree_block(root, btrfs_node_blockptr(path->nodes[1],
1830 slot - 1), root->leafsize);
1831 free_space = btrfs_leaf_free_space(root, left);
1832 if (free_space < data_size + sizeof(struct btrfs_item)) {
1833 free_extent_buffer(left);
1834 return 1;
1835 }
1836
1837 /* cow and double check */
1838 ret = btrfs_cow_block(trans, root, left,
1839 path->nodes[1], slot - 1, &left);
1840 if (ret) {
1841 /* we hit -ENOSPC, but it isn't fatal here */
1842 free_extent_buffer(left);
1843 return 1;
1844 }
1845
1846 free_space = btrfs_leaf_free_space(root, left);
1847 if (free_space < data_size + sizeof(struct btrfs_item)) {
1848 free_extent_buffer(left);
1849 return 1;
1850 }
1851
1852 if (empty)
1853 nr = right_nritems;
1854 else
1855 nr = right_nritems - 1;
1856
1857 for (i = 0; i < nr; i++) {
1858 item = btrfs_item_nr(right, i);
1859 if (!right->map_token) {
1860 map_extent_buffer(right, (unsigned long)item,
1861 sizeof(struct btrfs_item),
1862 &right->map_token, &right->kaddr,
1863 &right->map_start, &right->map_len,
1864 KM_USER1);
1865 }
1866
1867 if (path->slots[0] == i)
1868 push_space += data_size + sizeof(*item);
1869
1870 this_item_size = btrfs_item_size(right, item);
1871 if (this_item_size + sizeof(*item) + push_space > free_space)
1872 break;
1873
1874 push_items++;
1875 push_space += this_item_size + sizeof(*item);
1876 }
1877
1878 if (right->map_token) {
1879 unmap_extent_buffer(right, right->map_token, KM_USER1);
1880 right->map_token = NULL;
1881 }
1882
1883 if (push_items == 0) {
1884 free_extent_buffer(left);
1885 return 1;
1886 }
1887 if (!empty && push_items == btrfs_header_nritems(right))
1888 WARN_ON(1);
1889
1890 /* push data from right to left */
1891 copy_extent_buffer(left, right,
1892 btrfs_item_nr_offset(btrfs_header_nritems(left)),
1893 btrfs_item_nr_offset(0),
1894 push_items * sizeof(struct btrfs_item));
1895
1896 push_space = BTRFS_LEAF_DATA_SIZE(root) -
1897 btrfs_item_offset_nr(right, push_items -1);
1898
1899 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
1900 leaf_data_end(root, left) - push_space,
1901 btrfs_leaf_data(right) +
1902 btrfs_item_offset_nr(right, push_items - 1),
1903 push_space);
1904 old_left_nritems = btrfs_header_nritems(left);
1905 BUG_ON(old_left_nritems < 0);
1906
1907 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
1908 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1909 u32 ioff;
1910
1911 item = btrfs_item_nr(left, i);
1912 if (!left->map_token) {
1913 map_extent_buffer(left, (unsigned long)item,
1914 sizeof(struct btrfs_item),
1915 &left->map_token, &left->kaddr,
1916 &left->map_start, &left->map_len,
1917 KM_USER1);
1918 }
1919
1920 ioff = btrfs_item_offset(left, item);
1921 btrfs_set_item_offset(left, item,
1922 ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
1923 }
1924 btrfs_set_header_nritems(left, old_left_nritems + push_items);
1925 if (left->map_token) {
1926 unmap_extent_buffer(left, left->map_token, KM_USER1);
1927 left->map_token = NULL;
1928 }
1929
1930 /* fixup right node */
1931 if (push_items > right_nritems) {
1932 printk("push items %d nr %u\n", push_items, right_nritems);
1933 WARN_ON(1);
1934 }
1935
1936 if (push_items < right_nritems) {
1937 push_space = btrfs_item_offset_nr(right, push_items - 1) -
1938 leaf_data_end(root, right);
1939 memmove_extent_buffer(right, btrfs_leaf_data(right) +
1940 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1941 btrfs_leaf_data(right) +
1942 leaf_data_end(root, right), push_space);
1943
1944 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
1945 btrfs_item_nr_offset(push_items),
1946 (btrfs_header_nritems(right) - push_items) *
1947 sizeof(struct btrfs_item));
1948 }
1949 right_nritems -= push_items;
1950 btrfs_set_header_nritems(right, right_nritems);
1951 push_space = BTRFS_LEAF_DATA_SIZE(root);
1952 for (i = 0; i < right_nritems; i++) {
1953 item = btrfs_item_nr(right, i);
1954
1955 if (!right->map_token) {
1956 map_extent_buffer(right, (unsigned long)item,
1957 sizeof(struct btrfs_item),
1958 &right->map_token, &right->kaddr,
1959 &right->map_start, &right->map_len,
1960 KM_USER1);
1961 }
1962
1963 push_space = push_space - btrfs_item_size(right, item);
1964 btrfs_set_item_offset(right, item, push_space);
1965 }
1966 if (right->map_token) {
1967 unmap_extent_buffer(right, right->map_token, KM_USER1);
1968 right->map_token = NULL;
1969 }
1970
1971 btrfs_mark_buffer_dirty(left);
1972 if (right_nritems)
1973 btrfs_mark_buffer_dirty(right);
1974
1975 btrfs_item_key(right, &disk_key, 0);
1976 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1977 if (wret)
1978 ret = wret;
1979
1980 /* then fixup the leaf pointer in the path */
1981 if (path->slots[0] < push_items) {
1982 path->slots[0] += old_left_nritems;
1983 free_extent_buffer(path->nodes[0]);
1984 path->nodes[0] = left;
1985 path->slots[1] -= 1;
1986 } else {
1987 free_extent_buffer(left);
1988 path->slots[0] -= push_items;
1989 }
1990 BUG_ON(path->slots[0] < 0);
1991 return ret;
1992 }
1993
1994 /*
1995 * split the path's leaf in two, making sure there is at least data_size
1996 * available for the resulting leaf level of the path.
1997 *
1998 * returns 0 if all went well and < 0 on failure.
1999 */
2000 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
2001 *root, struct btrfs_key *ins_key,
2002 struct btrfs_path *path, int data_size, int extend)
2003 {
2004 u64 root_gen;
2005 struct extent_buffer *l;
2006 u32 nritems;
2007 int mid;
2008 int slot;
2009 struct extent_buffer *right;
2010 int space_needed = data_size + sizeof(struct btrfs_item);
2011 int data_copy_size;
2012 int rt_data_off;
2013 int i;
2014 int ret = 0;
2015 int wret;
2016 int double_split;
2017 int num_doubles = 0;
2018 struct btrfs_disk_key disk_key;
2019
2020 if (extend)
2021 space_needed = data_size;
2022
2023 if (root->ref_cows)
2024 root_gen = trans->transid;
2025 else
2026 root_gen = 0;
2027
2028 /* first try to make some room by pushing left and right */
2029 if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
2030 wret = push_leaf_right(trans, root, path, data_size, 0);
2031 if (wret < 0) {
2032 return wret;
2033 }
2034 if (wret) {
2035 wret = push_leaf_left(trans, root, path, data_size, 0);
2036 if (wret < 0)
2037 return wret;
2038 }
2039 l = path->nodes[0];
2040
2041 /* did the pushes work? */
2042 if (btrfs_leaf_free_space(root, l) >= space_needed)
2043 return 0;
2044 }
2045
2046 if (!path->nodes[1]) {
2047 ret = insert_new_root(trans, root, path, 1);
2048 if (ret)
2049 return ret;
2050 }
2051 again:
2052 double_split = 0;
2053 l = path->nodes[0];
2054 slot = path->slots[0];
2055 nritems = btrfs_header_nritems(l);
2056 mid = (nritems + 1)/ 2;
2057
2058 btrfs_item_key(l, &disk_key, 0);
2059
2060 right = __btrfs_alloc_free_block(trans, root, root->leafsize,
2061 root->root_key.objectid,
2062 root_gen, disk_key.objectid, 0,
2063 l->start, 0);
2064 if (IS_ERR(right)) {
2065 BUG_ON(1);
2066 return PTR_ERR(right);
2067 }
2068
2069 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
2070 btrfs_set_header_bytenr(right, right->start);
2071 btrfs_set_header_generation(right, trans->transid);
2072 btrfs_set_header_owner(right, root->root_key.objectid);
2073 btrfs_set_header_level(right, 0);
2074 write_extent_buffer(right, root->fs_info->fsid,
2075 (unsigned long)btrfs_header_fsid(right),
2076 BTRFS_FSID_SIZE);
2077
2078 write_extent_buffer(right, root->fs_info->chunk_tree_uuid,
2079 (unsigned long)btrfs_header_chunk_tree_uuid(right),
2080 BTRFS_UUID_SIZE);
2081 if (mid <= slot) {
2082 if (nritems == 1 ||
2083 leaf_space_used(l, mid, nritems - mid) + space_needed >
2084 BTRFS_LEAF_DATA_SIZE(root)) {
2085 if (slot >= nritems) {
2086 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2087 btrfs_set_header_nritems(right, 0);
2088 wret = insert_ptr(trans, root, path,
2089 &disk_key, right->start,
2090 path->slots[1] + 1, 1);
2091 if (wret)
2092 ret = wret;
2093 free_extent_buffer(path->nodes[0]);
2094 path->nodes[0] = right;
2095 path->slots[0] = 0;
2096 path->slots[1] += 1;
2097 btrfs_mark_buffer_dirty(right);
2098 return ret;
2099 }
2100 mid = slot;
2101 if (mid != nritems &&
2102 leaf_space_used(l, mid, nritems - mid) +
2103 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2104 double_split = 1;
2105 }
2106 }
2107 } else {
2108 if (leaf_space_used(l, 0, mid + 1) + space_needed >
2109 BTRFS_LEAF_DATA_SIZE(root)) {
2110 if (!extend && slot == 0) {
2111 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2112 btrfs_set_header_nritems(right, 0);
2113 wret = insert_ptr(trans, root, path,
2114 &disk_key,
2115 right->start,
2116 path->slots[1], 1);
2117 if (wret)
2118 ret = wret;
2119 free_extent_buffer(path->nodes[0]);
2120 path->nodes[0] = right;
2121 path->slots[0] = 0;
2122 if (path->slots[1] == 0) {
2123 wret = fixup_low_keys(trans, root,
2124 path, &disk_key, 1);
2125 if (wret)
2126 ret = wret;
2127 }
2128 btrfs_mark_buffer_dirty(right);
2129 return ret;
2130 } else if (extend && slot == 0) {
2131 mid = 1;
2132 } else {
2133 mid = slot;
2134 if (mid != nritems &&
2135 leaf_space_used(l, mid, nritems - mid) +
2136 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2137 double_split = 1;
2138 }
2139 }
2140 }
2141 }
2142 nritems = nritems - mid;
2143 btrfs_set_header_nritems(right, nritems);
2144 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
2145
2146 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
2147 btrfs_item_nr_offset(mid),
2148 nritems * sizeof(struct btrfs_item));
2149
2150 copy_extent_buffer(right, l,
2151 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
2152 data_copy_size, btrfs_leaf_data(l) +
2153 leaf_data_end(root, l), data_copy_size);
2154
2155 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
2156 btrfs_item_end_nr(l, mid);
2157
2158 for (i = 0; i < nritems; i++) {
2159 struct btrfs_item *item = btrfs_item_nr(right, i);
2160 u32 ioff;
2161
2162 if (!right->map_token) {
2163 map_extent_buffer(right, (unsigned long)item,
2164 sizeof(struct btrfs_item),
2165 &right->map_token, &right->kaddr,
2166 &right->map_start, &right->map_len,
2167 KM_USER1);
2168 }
2169
2170 ioff = btrfs_item_offset(right, item);
2171 btrfs_set_item_offset(right, item, ioff + rt_data_off);
2172 }
2173
2174 if (right->map_token) {
2175 unmap_extent_buffer(right, right->map_token, KM_USER1);
2176 right->map_token = NULL;
2177 }
2178
2179 btrfs_set_header_nritems(l, mid);
2180 ret = 0;
2181 btrfs_item_key(right, &disk_key, 0);
2182 wret = insert_ptr(trans, root, path, &disk_key, right->start,
2183 path->slots[1] + 1, 1);
2184 if (wret)
2185 ret = wret;
2186
2187 btrfs_mark_buffer_dirty(right);
2188 btrfs_mark_buffer_dirty(l);
2189 BUG_ON(path->slots[0] != slot);
2190
2191 if (mid <= slot) {
2192 free_extent_buffer(path->nodes[0]);
2193 path->nodes[0] = right;
2194 path->slots[0] -= mid;
2195 path->slots[1] += 1;
2196 } else
2197 free_extent_buffer(right);
2198
2199 BUG_ON(path->slots[0] < 0);
2200
2201 if (double_split) {
2202 BUG_ON(num_doubles != 0);
2203 num_doubles++;
2204 goto again;
2205 }
2206 return ret;
2207 }
2208
2209 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
2210 struct btrfs_root *root,
2211 struct btrfs_path *path,
2212 u32 new_size, int from_end)
2213 {
2214 int ret = 0;
2215 int slot;
2216 int slot_orig;
2217 struct extent_buffer *leaf;
2218 struct btrfs_item *item;
2219 u32 nritems;
2220 unsigned int data_end;
2221 unsigned int old_data_start;
2222 unsigned int old_size;
2223 unsigned int size_diff;
2224 int i;
2225
2226 slot_orig = path->slots[0];
2227 leaf = path->nodes[0];
2228 slot = path->slots[0];
2229
2230 old_size = btrfs_item_size_nr(leaf, slot);
2231 if (old_size == new_size)
2232 return 0;
2233
2234 nritems = btrfs_header_nritems(leaf);
2235 data_end = leaf_data_end(root, leaf);
2236
2237 old_data_start = btrfs_item_offset_nr(leaf, slot);
2238
2239 size_diff = old_size - new_size;
2240
2241 BUG_ON(slot < 0);
2242 BUG_ON(slot >= nritems);
2243
2244 /*
2245 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2246 */
2247 /* first correct the data pointers */
2248 for (i = slot; i < nritems; i++) {
2249 u32 ioff;
2250 item = btrfs_item_nr(leaf, i);
2251
2252 if (!leaf->map_token) {
2253 map_extent_buffer(leaf, (unsigned long)item,
2254 sizeof(struct btrfs_item),
2255 &leaf->map_token, &leaf->kaddr,
2256 &leaf->map_start, &leaf->map_len,
2257 KM_USER1);
2258 }
2259
2260 ioff = btrfs_item_offset(leaf, item);
2261 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2262 }
2263
2264 if (leaf->map_token) {
2265 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2266 leaf->map_token = NULL;
2267 }
2268
2269 /* shift the data */
2270 if (from_end) {
2271 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2272 data_end + size_diff, btrfs_leaf_data(leaf) +
2273 data_end, old_data_start + new_size - data_end);
2274 } else {
2275 struct btrfs_disk_key disk_key;
2276 u64 offset;
2277
2278 btrfs_item_key(leaf, &disk_key, slot);
2279
2280 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2281 unsigned long ptr;
2282 struct btrfs_file_extent_item *fi;
2283
2284 fi = btrfs_item_ptr(leaf, slot,
2285 struct btrfs_file_extent_item);
2286 fi = (struct btrfs_file_extent_item *)(
2287 (unsigned long)fi - size_diff);
2288
2289 if (btrfs_file_extent_type(leaf, fi) ==
2290 BTRFS_FILE_EXTENT_INLINE) {
2291 ptr = btrfs_item_ptr_offset(leaf, slot);
2292 memmove_extent_buffer(leaf, ptr,
2293 (unsigned long)fi,
2294 offsetof(struct btrfs_file_extent_item,
2295 disk_bytenr));
2296 }
2297 }
2298
2299 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2300 data_end + size_diff, btrfs_leaf_data(leaf) +
2301 data_end, old_data_start - data_end);
2302
2303 offset = btrfs_disk_key_offset(&disk_key);
2304 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2305 btrfs_set_item_key(leaf, &disk_key, slot);
2306 if (slot == 0)
2307 fixup_low_keys(trans, root, path, &disk_key, 1);
2308 }
2309
2310 item = btrfs_item_nr(leaf, slot);
2311 btrfs_set_item_size(leaf, item, new_size);
2312 btrfs_mark_buffer_dirty(leaf);
2313
2314 ret = 0;
2315 if (btrfs_leaf_free_space(root, leaf) < 0) {
2316 btrfs_print_leaf(root, leaf);
2317 BUG();
2318 }
2319 return ret;
2320 }
2321
2322 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2323 struct btrfs_root *root, struct btrfs_path *path,
2324 u32 data_size)
2325 {
2326 int ret = 0;
2327 int slot;
2328 int slot_orig;
2329 struct extent_buffer *leaf;
2330 struct btrfs_item *item;
2331 u32 nritems;
2332 unsigned int data_end;
2333 unsigned int old_data;
2334 unsigned int old_size;
2335 int i;
2336
2337 slot_orig = path->slots[0];
2338 leaf = path->nodes[0];
2339
2340 nritems = btrfs_header_nritems(leaf);
2341 data_end = leaf_data_end(root, leaf);
2342
2343 if (btrfs_leaf_free_space(root, leaf) < data_size) {
2344 btrfs_print_leaf(root, leaf);
2345 BUG();
2346 }
2347 slot = path->slots[0];
2348 old_data = btrfs_item_end_nr(leaf, slot);
2349
2350 BUG_ON(slot < 0);
2351 if (slot >= nritems) {
2352 btrfs_print_leaf(root, leaf);
2353 printk("slot %d too large, nritems %d\n", slot, nritems);
2354 BUG_ON(1);
2355 }
2356
2357 /*
2358 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2359 */
2360 /* first correct the data pointers */
2361 for (i = slot; i < nritems; i++) {
2362 u32 ioff;
2363 item = btrfs_item_nr(leaf, i);
2364
2365 if (!leaf->map_token) {
2366 map_extent_buffer(leaf, (unsigned long)item,
2367 sizeof(struct btrfs_item),
2368 &leaf->map_token, &leaf->kaddr,
2369 &leaf->map_start, &leaf->map_len,
2370 KM_USER1);
2371 }
2372 ioff = btrfs_item_offset(leaf, item);
2373 btrfs_set_item_offset(leaf, item, ioff - data_size);
2374 }
2375
2376 if (leaf->map_token) {
2377 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2378 leaf->map_token = NULL;
2379 }
2380
2381 /* shift the data */
2382 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2383 data_end - data_size, btrfs_leaf_data(leaf) +
2384 data_end, old_data - data_end);
2385
2386 data_end = old_data;
2387 old_size = btrfs_item_size_nr(leaf, slot);
2388 item = btrfs_item_nr(leaf, slot);
2389 btrfs_set_item_size(leaf, item, old_size + data_size);
2390 btrfs_mark_buffer_dirty(leaf);
2391
2392 ret = 0;
2393 if (btrfs_leaf_free_space(root, leaf) < 0) {
2394 btrfs_print_leaf(root, leaf);
2395 BUG();
2396 }
2397 return ret;
2398 }
2399
2400 /*
2401 * Given a key and some data, insert an item into the tree.
2402 * This does all the path init required, making room in the tree if needed.
2403 */
2404 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
2405 struct btrfs_root *root,
2406 struct btrfs_path *path,
2407 struct btrfs_key *cpu_key, u32 *data_size,
2408 int nr)
2409 {
2410 struct extent_buffer *leaf;
2411 struct btrfs_item *item;
2412 int ret = 0;
2413 int slot;
2414 int slot_orig;
2415 int i;
2416 u32 nritems;
2417 u32 total_size = 0;
2418 u32 total_data = 0;
2419 unsigned int data_end;
2420 struct btrfs_disk_key disk_key;
2421
2422 for (i = 0; i < nr; i++) {
2423 total_data += data_size[i];
2424 }
2425
2426 /* create a root if there isn't one */
2427 if (!root->node)
2428 BUG();
2429
2430 total_size = total_data + (nr - 1) * sizeof(struct btrfs_item);
2431 ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
2432 if (ret == 0) {
2433 return -EEXIST;
2434 }
2435 if (ret < 0)
2436 goto out;
2437
2438 slot_orig = path->slots[0];
2439 leaf = path->nodes[0];
2440
2441 nritems = btrfs_header_nritems(leaf);
2442 data_end = leaf_data_end(root, leaf);
2443
2444 if (btrfs_leaf_free_space(root, leaf) <
2445 sizeof(struct btrfs_item) + total_size) {
2446 btrfs_print_leaf(root, leaf);
2447 printk("not enough freespace need %u have %d\n",
2448 total_size, btrfs_leaf_free_space(root, leaf));
2449 BUG();
2450 }
2451
2452 slot = path->slots[0];
2453 BUG_ON(slot < 0);
2454
2455 if (slot != nritems) {
2456 int i;
2457 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2458
2459 if (old_data < data_end) {
2460 btrfs_print_leaf(root, leaf);
2461 printk("slot %d old_data %d data_end %d\n",
2462 slot, old_data, data_end);
2463 BUG_ON(1);
2464 }
2465 /*
2466 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2467 */
2468 /* first correct the data pointers */
2469 WARN_ON(leaf->map_token);
2470 for (i = slot; i < nritems; i++) {
2471 u32 ioff;
2472
2473 item = btrfs_item_nr(leaf, i);
2474 if (!leaf->map_token) {
2475 map_extent_buffer(leaf, (unsigned long)item,
2476 sizeof(struct btrfs_item),
2477 &leaf->map_token, &leaf->kaddr,
2478 &leaf->map_start, &leaf->map_len,
2479 KM_USER1);
2480 }
2481
2482 ioff = btrfs_item_offset(leaf, item);
2483 btrfs_set_item_offset(leaf, item, ioff - total_data);
2484 }
2485 if (leaf->map_token) {
2486 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2487 leaf->map_token = NULL;
2488 }
2489
2490 /* shift the items */
2491 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
2492 btrfs_item_nr_offset(slot),
2493 (nritems - slot) * sizeof(struct btrfs_item));
2494
2495 /* shift the data */
2496 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2497 data_end - total_data, btrfs_leaf_data(leaf) +
2498 data_end, old_data - data_end);
2499 data_end = old_data;
2500 }
2501
2502 /* setup the item for the new data */
2503 for (i = 0; i < nr; i++) {
2504 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
2505 btrfs_set_item_key(leaf, &disk_key, slot + i);
2506 item = btrfs_item_nr(leaf, slot + i);
2507 btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
2508 data_end -= data_size[i];
2509 btrfs_set_item_size(leaf, item, data_size[i]);
2510 }
2511 btrfs_set_header_nritems(leaf, nritems + nr);
2512 btrfs_mark_buffer_dirty(leaf);
2513
2514 ret = 0;
2515 if (slot == 0) {
2516 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2517 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2518 }
2519
2520 if (btrfs_leaf_free_space(root, leaf) < 0) {
2521 btrfs_print_leaf(root, leaf);
2522 BUG();
2523 }
2524
2525 out:
2526 return ret;
2527 }
2528
2529 /*
2530 * Given a key and some data, insert an item into the tree.
2531 * This does all the path init required, making room in the tree if needed.
2532 */
2533 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2534 *root, struct btrfs_key *cpu_key, void *data, u32
2535 data_size)
2536 {
2537 int ret = 0;
2538 struct btrfs_path *path;
2539 struct extent_buffer *leaf;
2540 unsigned long ptr;
2541
2542 path = btrfs_alloc_path();
2543 BUG_ON(!path);
2544 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2545 if (!ret) {
2546 leaf = path->nodes[0];
2547 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2548 write_extent_buffer(leaf, data, ptr, data_size);
2549 btrfs_mark_buffer_dirty(leaf);
2550 }
2551 btrfs_free_path(path);
2552 return ret;
2553 }
2554
2555 /*
2556 * delete the pointer from a given node.
2557 *
2558 * If the delete empties a node, the node is removed from the tree,
2559 * continuing all the way the root if required. The root is converted into
2560 * a leaf if all the nodes are emptied.
2561 */
2562 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2563 struct btrfs_path *path, int level, int slot)
2564 {
2565 struct extent_buffer *parent = path->nodes[level];
2566 u32 nritems;
2567 int ret = 0;
2568 int wret;
2569
2570 nritems = btrfs_header_nritems(parent);
2571 if (slot != nritems -1) {
2572 memmove_extent_buffer(parent,
2573 btrfs_node_key_ptr_offset(slot),
2574 btrfs_node_key_ptr_offset(slot + 1),
2575 sizeof(struct btrfs_key_ptr) *
2576 (nritems - slot - 1));
2577 }
2578 nritems--;
2579 btrfs_set_header_nritems(parent, nritems);
2580 if (nritems == 0 && parent == root->node) {
2581 BUG_ON(btrfs_header_level(root->node) != 1);
2582 /* just turn the root into a leaf and break */
2583 btrfs_set_header_level(root->node, 0);
2584 } else if (slot == 0) {
2585 struct btrfs_disk_key disk_key;
2586
2587 btrfs_node_key(parent, &disk_key, 0);
2588 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2589 if (wret)
2590 ret = wret;
2591 }
2592 btrfs_mark_buffer_dirty(parent);
2593 return ret;
2594 }
2595
2596 /*
2597 * delete the item at the leaf level in path. If that empties
2598 * the leaf, remove it from the tree
2599 */
2600 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2601 struct btrfs_path *path, int slot, int nr)
2602 {
2603 struct extent_buffer *leaf;
2604 struct btrfs_item *item;
2605 int last_off;
2606 int dsize = 0;
2607 int ret = 0;
2608 int wret;
2609 int i;
2610 u32 nritems;
2611
2612 leaf = path->nodes[0];
2613 last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
2614
2615 for (i = 0; i < nr; i++)
2616 dsize += btrfs_item_size_nr(leaf, slot + i);
2617
2618 nritems = btrfs_header_nritems(leaf);
2619
2620 if (slot + nr != nritems) {
2621 int i;
2622 int data_end = leaf_data_end(root, leaf);
2623
2624 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2625 data_end + dsize,
2626 btrfs_leaf_data(leaf) + data_end,
2627 last_off - data_end);
2628
2629 for (i = slot + nr; i < nritems; i++) {
2630 u32 ioff;
2631
2632 item = btrfs_item_nr(leaf, i);
2633 if (!leaf->map_token) {
2634 map_extent_buffer(leaf, (unsigned long)item,
2635 sizeof(struct btrfs_item),
2636 &leaf->map_token, &leaf->kaddr,
2637 &leaf->map_start, &leaf->map_len,
2638 KM_USER1);
2639 }
2640 ioff = btrfs_item_offset(leaf, item);
2641 btrfs_set_item_offset(leaf, item, ioff + dsize);
2642 }
2643
2644 if (leaf->map_token) {
2645 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2646 leaf->map_token = NULL;
2647 }
2648
2649 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2650 btrfs_item_nr_offset(slot + nr),
2651 sizeof(struct btrfs_item) *
2652 (nritems - slot - nr));
2653 }
2654 btrfs_set_header_nritems(leaf, nritems - nr);
2655 nritems -= nr;
2656
2657 /* delete the leaf if we've emptied it */
2658 if (nritems == 0) {
2659 if (leaf == root->node) {
2660 btrfs_set_header_level(leaf, 0);
2661 } else {
2662 u64 root_gen = btrfs_header_generation(path->nodes[1]);
2663 clean_tree_block(trans, root, leaf);
2664 wret = del_ptr(trans, root, path, 1, path->slots[1]);
2665 if (wret)
2666 ret = wret;
2667 wret = btrfs_free_extent(trans, root,
2668 leaf->start, leaf->len,
2669 btrfs_header_owner(path->nodes[1]),
2670 root_gen, 0, 0, 1);
2671 if (wret)
2672 ret = wret;
2673 }
2674 } else {
2675 int used = leaf_space_used(leaf, 0, nritems);
2676 if (slot == 0) {
2677 struct btrfs_disk_key disk_key;
2678
2679 btrfs_item_key(leaf, &disk_key, 0);
2680 wret = fixup_low_keys(trans, root, path,
2681 &disk_key, 1);
2682 if (wret)
2683 ret = wret;
2684 }
2685
2686 /* delete the leaf if it is mostly empty */
2687 if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
2688 /* push_leaf_left fixes the path.
2689 * make sure the path still points to our leaf
2690 * for possible call to del_ptr below
2691 */
2692 slot = path->slots[1];
2693 extent_buffer_get(leaf);
2694
2695 wret = push_leaf_left(trans, root, path, 1, 1);
2696 if (wret < 0 && wret != -ENOSPC)
2697 ret = wret;
2698
2699 if (path->nodes[0] == leaf &&
2700 btrfs_header_nritems(leaf)) {
2701 wret = push_leaf_right(trans, root, path, 1, 1);
2702 if (wret < 0 && wret != -ENOSPC)
2703 ret = wret;
2704 }
2705
2706 if (btrfs_header_nritems(leaf) == 0) {
2707 u64 root_gen;
2708 u64 bytenr = leaf->start;
2709 u32 blocksize = leaf->len;
2710
2711 root_gen = btrfs_header_generation(
2712 path->nodes[1]);
2713
2714 clean_tree_block(trans, root, leaf);
2715
2716 wret = del_ptr(trans, root, path, 1, slot);
2717 if (wret)
2718 ret = wret;
2719
2720 free_extent_buffer(leaf);
2721 wret = btrfs_free_extent(trans, root, bytenr,
2722 blocksize,
2723 btrfs_header_owner(path->nodes[1]),
2724 root_gen, 0, 0, 1);
2725 if (wret)
2726 ret = wret;
2727 } else {
2728 btrfs_mark_buffer_dirty(leaf);
2729 free_extent_buffer(leaf);
2730 }
2731 } else {
2732 btrfs_mark_buffer_dirty(leaf);
2733 }
2734 }
2735 return ret;
2736 }
2737
2738 /*
2739 * walk up the tree as far as required to find the previous leaf.
2740 * returns 0 if it found something or 1 if there are no lesser leaves.
2741 * returns < 0 on io errors.
2742 */
2743 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
2744 {
2745 u64 bytenr;
2746 int slot;
2747 int level = 1;
2748 struct extent_buffer *c;
2749 struct extent_buffer *next = NULL;
2750
2751 while(level < BTRFS_MAX_LEVEL) {
2752 if (!path->nodes[level])
2753 return 1;
2754
2755 slot = path->slots[level];
2756 c = path->nodes[level];
2757 if (slot == 0) {
2758 level++;
2759 if (level == BTRFS_MAX_LEVEL)
2760 return 1;
2761 continue;
2762 }
2763 slot--;
2764
2765 bytenr = btrfs_node_blockptr(c, slot);
2766 if (next)
2767 free_extent_buffer(next);
2768
2769 next = read_tree_block(root, bytenr,
2770 btrfs_level_size(root, level - 1));
2771 break;
2772 }
2773 path->slots[level] = slot;
2774 while(1) {
2775 level--;
2776 c = path->nodes[level];
2777 free_extent_buffer(c);
2778 slot = btrfs_header_nritems(next);
2779 if (slot != 0)
2780 slot--;
2781 path->nodes[level] = next;
2782 path->slots[level] = slot;
2783 if (!level)
2784 break;
2785 next = read_tree_block(root, btrfs_node_blockptr(next, slot),
2786 btrfs_level_size(root, level - 1));
2787 }
2788 return 0;
2789 }
2790
2791 /*
2792 * walk up the tree as far as required to find the next leaf.
2793 * returns 0 if it found something or 1 if there are no greater leaves.
2794 * returns < 0 on io errors.
2795 */
2796 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2797 {
2798 int slot;
2799 int level = 1;
2800 u64 bytenr;
2801 struct extent_buffer *c;
2802 struct extent_buffer *next = NULL;
2803
2804 while(level < BTRFS_MAX_LEVEL) {
2805 if (!path->nodes[level])
2806 return 1;
2807
2808 slot = path->slots[level] + 1;
2809 c = path->nodes[level];
2810 if (slot >= btrfs_header_nritems(c)) {
2811 level++;
2812 if (level == BTRFS_MAX_LEVEL)
2813 return 1;
2814 continue;
2815 }
2816
2817 bytenr = btrfs_node_blockptr(c, slot);
2818 if (next)
2819 free_extent_buffer(next);
2820
2821 if (path->reada)
2822 reada_for_search(root, path, level, slot, 0);
2823
2824 next = read_tree_block(root, bytenr,
2825 btrfs_level_size(root, level -1));
2826 break;
2827 }
2828 path->slots[level] = slot;
2829 while(1) {
2830 level--;
2831 c = path->nodes[level];
2832 free_extent_buffer(c);
2833 path->nodes[level] = next;
2834 path->slots[level] = 0;
2835 if (!level)
2836 break;
2837 if (path->reada)
2838 reada_for_search(root, path, level, 0, 0);
2839 next = read_tree_block(root, btrfs_node_blockptr(next, 0),
2840 btrfs_level_size(root, level - 1));
2841 }
2842 return 0;
2843 }
2844
2845 int btrfs_previous_item(struct btrfs_root *root,
2846 struct btrfs_path *path, u64 min_objectid,
2847 int type)
2848 {
2849 struct btrfs_key found_key;
2850 struct extent_buffer *leaf;
2851 int ret;
2852
2853 while(1) {
2854 if (path->slots[0] == 0) {
2855 ret = btrfs_prev_leaf(root, path);
2856 if (ret != 0)
2857 return ret;
2858 } else {
2859 path->slots[0]--;
2860 }
2861 leaf = path->nodes[0];
2862 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2863 if (found_key.type == type)
2864 return 0;
2865 }
2866 return 1;
2867 }
2868
Linux kernel - Deliverables
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