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efce173a935c5d284595a7bf6e8a6c2266a7e34e
[deliverable/linux.git] / fs / btrfs / ctree.c
1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/sched.h>
20 #include "ctree.h"
21 #include "disk-io.h"
22 #include "transaction.h"
23 #include "print-tree.h"
24
25 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
26 *root, struct btrfs_path *path, int level);
27 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
28 *root, struct btrfs_key *ins_key,
29 struct btrfs_path *path, int data_size, int extend);
30 static int push_node_left(struct btrfs_trans_handle *trans,
31 struct btrfs_root *root, struct extent_buffer *dst,
32 struct extent_buffer *src);
33 static int balance_node_right(struct btrfs_trans_handle *trans,
34 struct btrfs_root *root,
35 struct extent_buffer *dst_buf,
36 struct extent_buffer *src_buf);
37 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
38 struct btrfs_path *path, int level, int slot);
39
40 inline void btrfs_init_path(struct btrfs_path *p)
41 {
42 memset(p, 0, sizeof(*p));
43 }
44
45 struct btrfs_path *btrfs_alloc_path(void)
46 {
47 struct btrfs_path *path;
48 path = kmem_cache_alloc(btrfs_path_cachep, GFP_NOFS);
49 if (path) {
50 btrfs_init_path(path);
51 path->reada = 1;
52 }
53 return path;
54 }
55
56 void btrfs_free_path(struct btrfs_path *p)
57 {
58 btrfs_release_path(NULL, p);
59 kmem_cache_free(btrfs_path_cachep, p);
60 }
61
62 void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
63 {
64 int i;
65 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
66 if (!p->nodes[i])
67 break;
68 free_extent_buffer(p->nodes[i]);
69 }
70 memset(p, 0, sizeof(*p));
71 }
72
73 static void add_root_to_dirty_list(struct btrfs_root *root)
74 {
75 if (root->track_dirty && list_empty(&root->dirty_list)) {
76 list_add(&root->dirty_list,
77 &root->fs_info->dirty_cowonly_roots);
78 }
79 }
80
81 int btrfs_copy_root(struct btrfs_trans_handle *trans,
82 struct btrfs_root *root,
83 struct extent_buffer *buf,
84 struct extent_buffer **cow_ret, u64 new_root_objectid)
85 {
86 struct extent_buffer *cow;
87 u32 nritems;
88 int ret = 0;
89 int level;
90 struct btrfs_key first_key;
91 struct btrfs_root *new_root;
92
93 new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
94 if (!new_root)
95 return -ENOMEM;
96
97 memcpy(new_root, root, sizeof(*new_root));
98 new_root->root_key.objectid = new_root_objectid;
99
100 WARN_ON(root->ref_cows && trans->transid !=
101 root->fs_info->running_transaction->transid);
102 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
103
104 level = btrfs_header_level(buf);
105 nritems = btrfs_header_nritems(buf);
106 if (nritems) {
107 if (level == 0)
108 btrfs_item_key_to_cpu(buf, &first_key, 0);
109 else
110 btrfs_node_key_to_cpu(buf, &first_key, 0);
111 } else {
112 first_key.objectid = 0;
113 }
114 cow = __btrfs_alloc_free_block(trans, new_root, buf->len,
115 new_root_objectid,
116 trans->transid, first_key.objectid,
117 level, buf->start, 0);
118 if (IS_ERR(cow)) {
119 kfree(new_root);
120 return PTR_ERR(cow);
121 }
122
123 copy_extent_buffer(cow, buf, 0, 0, cow->len);
124 btrfs_set_header_bytenr(cow, cow->start);
125 btrfs_set_header_generation(cow, trans->transid);
126 btrfs_set_header_owner(cow, new_root_objectid);
127 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
128
129 WARN_ON(btrfs_header_generation(buf) > trans->transid);
130 ret = btrfs_inc_ref(trans, new_root, buf);
131 kfree(new_root);
132
133 if (ret)
134 return ret;
135
136 btrfs_mark_buffer_dirty(cow);
137 *cow_ret = cow;
138 return 0;
139 }
140
141 int __btrfs_cow_block(struct btrfs_trans_handle *trans,
142 struct btrfs_root *root,
143 struct extent_buffer *buf,
144 struct extent_buffer *parent, int parent_slot,
145 struct extent_buffer **cow_ret,
146 u64 search_start, u64 empty_size)
147 {
148 u64 root_gen;
149 struct extent_buffer *cow;
150 u32 nritems;
151 int ret = 0;
152 int different_trans = 0;
153 int level;
154 struct btrfs_key first_key;
155
156 if (root->ref_cows) {
157 root_gen = trans->transid;
158 } else {
159 root_gen = 0;
160 }
161 WARN_ON(root->ref_cows && trans->transid !=
162 root->fs_info->running_transaction->transid);
163 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
164
165 level = btrfs_header_level(buf);
166 nritems = btrfs_header_nritems(buf);
167 if (nritems) {
168 if (level == 0)
169 btrfs_item_key_to_cpu(buf, &first_key, 0);
170 else
171 btrfs_node_key_to_cpu(buf, &first_key, 0);
172 } else {
173 first_key.objectid = 0;
174 }
175 cow = __btrfs_alloc_free_block(trans, root, buf->len,
176 root->root_key.objectid,
177 root_gen, first_key.objectid, level,
178 search_start, empty_size);
179 if (IS_ERR(cow))
180 return PTR_ERR(cow);
181
182 copy_extent_buffer(cow, buf, 0, 0, cow->len);
183 btrfs_set_header_bytenr(cow, cow->start);
184 btrfs_set_header_generation(cow, trans->transid);
185 btrfs_set_header_owner(cow, root->root_key.objectid);
186 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
187
188 WARN_ON(btrfs_header_generation(buf) > trans->transid);
189 if (btrfs_header_generation(buf) != trans->transid) {
190 different_trans = 1;
191 ret = btrfs_inc_ref(trans, root, buf);
192 if (ret)
193 return ret;
194 } else {
195 clean_tree_block(trans, root, buf);
196 }
197
198 if (buf == root->node) {
199 root_gen = btrfs_header_generation(buf);
200 root->node = cow;
201 extent_buffer_get(cow);
202 if (buf != root->commit_root) {
203 btrfs_free_extent(trans, root, buf->start,
204 buf->len, root->root_key.objectid,
205 root_gen, 0, 0, 1);
206 }
207 free_extent_buffer(buf);
208 add_root_to_dirty_list(root);
209 } else {
210 root_gen = btrfs_header_generation(parent);
211 btrfs_set_node_blockptr(parent, parent_slot,
212 cow->start);
213 WARN_ON(trans->transid == 0);
214 btrfs_set_node_ptr_generation(parent, parent_slot,
215 trans->transid);
216 btrfs_mark_buffer_dirty(parent);
217 WARN_ON(btrfs_header_generation(parent) != trans->transid);
218 btrfs_free_extent(trans, root, buf->start, buf->len,
219 btrfs_header_owner(parent), root_gen,
220 0, 0, 1);
221 }
222 free_extent_buffer(buf);
223 btrfs_mark_buffer_dirty(cow);
224 *cow_ret = cow;
225 return 0;
226 }
227
228 int btrfs_cow_block(struct btrfs_trans_handle *trans,
229 struct btrfs_root *root, struct extent_buffer *buf,
230 struct extent_buffer *parent, int parent_slot,
231 struct extent_buffer **cow_ret)
232 {
233 u64 search_start;
234 u64 header_trans;
235 int ret;
236
237 if (trans->transaction != root->fs_info->running_transaction) {
238 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
239 root->fs_info->running_transaction->transid);
240 WARN_ON(1);
241 }
242 if (trans->transid != root->fs_info->generation) {
243 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
244 root->fs_info->generation);
245 WARN_ON(1);
246 }
247
248 header_trans = btrfs_header_generation(buf);
249 spin_lock(&root->fs_info->hash_lock);
250 if (header_trans == trans->transid &&
251 !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
252 *cow_ret = buf;
253 spin_unlock(&root->fs_info->hash_lock);
254 return 0;
255 }
256 spin_unlock(&root->fs_info->hash_lock);
257 search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
258 ret = __btrfs_cow_block(trans, root, buf, parent,
259 parent_slot, cow_ret, search_start, 0);
260 return ret;
261 }
262
263 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
264 {
265 if (blocknr < other && other - (blocknr + blocksize) < 32768)
266 return 1;
267 if (blocknr > other && blocknr - (other + blocksize) < 32768)
268 return 1;
269 return 0;
270 }
271
272 /*
273 * compare two keys in a memcmp fashion
274 */
275 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
276 {
277 struct btrfs_key k1;
278
279 btrfs_disk_key_to_cpu(&k1, disk);
280
281 if (k1.objectid > k2->objectid)
282 return 1;
283 if (k1.objectid < k2->objectid)
284 return -1;
285 if (k1.type > k2->type)
286 return 1;
287 if (k1.type < k2->type)
288 return -1;
289 if (k1.offset > k2->offset)
290 return 1;
291 if (k1.offset < k2->offset)
292 return -1;
293 return 0;
294 }
295
296
297 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
298 struct btrfs_root *root, struct extent_buffer *parent,
299 int start_slot, int cache_only, u64 *last_ret,
300 struct btrfs_key *progress)
301 {
302 struct extent_buffer *cur;
303 struct extent_buffer *tmp;
304 u64 blocknr;
305 u64 search_start = *last_ret;
306 u64 last_block = 0;
307 u64 other;
308 u32 parent_nritems;
309 int end_slot;
310 int i;
311 int err = 0;
312 int parent_level;
313 int uptodate;
314 u32 blocksize;
315 int progress_passed = 0;
316 struct btrfs_disk_key disk_key;
317
318 parent_level = btrfs_header_level(parent);
319 if (cache_only && parent_level != 1)
320 return 0;
321
322 if (trans->transaction != root->fs_info->running_transaction) {
323 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
324 root->fs_info->running_transaction->transid);
325 WARN_ON(1);
326 }
327 if (trans->transid != root->fs_info->generation) {
328 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
329 root->fs_info->generation);
330 WARN_ON(1);
331 }
332
333 parent_nritems = btrfs_header_nritems(parent);
334 blocksize = btrfs_level_size(root, parent_level - 1);
335 end_slot = parent_nritems;
336
337 if (parent_nritems == 1)
338 return 0;
339
340 for (i = start_slot; i < end_slot; i++) {
341 int close = 1;
342
343 if (!parent->map_token) {
344 map_extent_buffer(parent,
345 btrfs_node_key_ptr_offset(i),
346 sizeof(struct btrfs_key_ptr),
347 &parent->map_token, &parent->kaddr,
348 &parent->map_start, &parent->map_len,
349 KM_USER1);
350 }
351 btrfs_node_key(parent, &disk_key, i);
352 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
353 continue;
354
355 progress_passed = 1;
356 blocknr = btrfs_node_blockptr(parent, i);
357 if (last_block == 0)
358 last_block = blocknr;
359
360 if (i > 0) {
361 other = btrfs_node_blockptr(parent, i - 1);
362 close = close_blocks(blocknr, other, blocksize);
363 }
364 if (close && i < end_slot - 2) {
365 other = btrfs_node_blockptr(parent, i + 1);
366 close = close_blocks(blocknr, other, blocksize);
367 }
368 if (close) {
369 last_block = blocknr;
370 continue;
371 }
372 if (parent->map_token) {
373 unmap_extent_buffer(parent, parent->map_token,
374 KM_USER1);
375 parent->map_token = NULL;
376 }
377
378 cur = btrfs_find_tree_block(root, blocknr, blocksize);
379 if (cur)
380 uptodate = btrfs_buffer_uptodate(cur);
381 else
382 uptodate = 0;
383 if (!cur || !uptodate) {
384 if (cache_only) {
385 free_extent_buffer(cur);
386 continue;
387 }
388 if (!cur) {
389 cur = read_tree_block(root, blocknr,
390 blocksize);
391 } else if (!uptodate) {
392 btrfs_read_buffer(cur);
393 }
394 }
395 if (search_start == 0)
396 search_start = last_block;
397
398 btrfs_verify_block_csum(root, cur);
399 err = __btrfs_cow_block(trans, root, cur, parent, i,
400 &tmp, search_start,
401 min(16 * blocksize,
402 (end_slot - i) * blocksize));
403 if (err) {
404 free_extent_buffer(cur);
405 break;
406 }
407 search_start = tmp->start;
408 last_block = tmp->start;
409 *last_ret = search_start;
410 if (parent_level == 1)
411 btrfs_clear_buffer_defrag(tmp);
412 free_extent_buffer(tmp);
413 }
414 if (parent->map_token) {
415 unmap_extent_buffer(parent, parent->map_token,
416 KM_USER1);
417 parent->map_token = NULL;
418 }
419 return err;
420 }
421
422 /*
423 * The leaf data grows from end-to-front in the node.
424 * this returns the address of the start of the last item,
425 * which is the stop of the leaf data stack
426 */
427 static inline unsigned int leaf_data_end(struct btrfs_root *root,
428 struct extent_buffer *leaf)
429 {
430 u32 nr = btrfs_header_nritems(leaf);
431 if (nr == 0)
432 return BTRFS_LEAF_DATA_SIZE(root);
433 return btrfs_item_offset_nr(leaf, nr - 1);
434 }
435
436 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
437 int level)
438 {
439 struct extent_buffer *parent = NULL;
440 struct extent_buffer *node = path->nodes[level];
441 struct btrfs_disk_key parent_key;
442 struct btrfs_disk_key node_key;
443 int parent_slot;
444 int slot;
445 struct btrfs_key cpukey;
446 u32 nritems = btrfs_header_nritems(node);
447
448 if (path->nodes[level + 1])
449 parent = path->nodes[level + 1];
450
451 slot = path->slots[level];
452 BUG_ON(nritems == 0);
453 if (parent) {
454 parent_slot = path->slots[level + 1];
455 btrfs_node_key(parent, &parent_key, parent_slot);
456 btrfs_node_key(node, &node_key, 0);
457 BUG_ON(memcmp(&parent_key, &node_key,
458 sizeof(struct btrfs_disk_key)));
459 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
460 btrfs_header_bytenr(node));
461 }
462 BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
463 if (slot != 0) {
464 btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
465 btrfs_node_key(node, &node_key, slot);
466 BUG_ON(comp_keys(&node_key, &cpukey) <= 0);
467 }
468 if (slot < nritems - 1) {
469 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
470 btrfs_node_key(node, &node_key, slot);
471 BUG_ON(comp_keys(&node_key, &cpukey) >= 0);
472 }
473 return 0;
474 }
475
476 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
477 int level)
478 {
479 struct extent_buffer *leaf = path->nodes[level];
480 struct extent_buffer *parent = NULL;
481 int parent_slot;
482 struct btrfs_key cpukey;
483 struct btrfs_disk_key parent_key;
484 struct btrfs_disk_key leaf_key;
485 int slot = path->slots[0];
486
487 u32 nritems = btrfs_header_nritems(leaf);
488
489 if (path->nodes[level + 1])
490 parent = path->nodes[level + 1];
491
492 if (nritems == 0)
493 return 0;
494
495 if (parent) {
496 parent_slot = path->slots[level + 1];
497 btrfs_node_key(parent, &parent_key, parent_slot);
498 btrfs_item_key(leaf, &leaf_key, 0);
499
500 BUG_ON(memcmp(&parent_key, &leaf_key,
501 sizeof(struct btrfs_disk_key)));
502 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
503 btrfs_header_bytenr(leaf));
504 }
505 #if 0
506 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
507 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
508 btrfs_item_key(leaf, &leaf_key, i);
509 if (comp_keys(&leaf_key, &cpukey) >= 0) {
510 btrfs_print_leaf(root, leaf);
511 printk("slot %d offset bad key\n", i);
512 BUG_ON(1);
513 }
514 if (btrfs_item_offset_nr(leaf, i) !=
515 btrfs_item_end_nr(leaf, i + 1)) {
516 btrfs_print_leaf(root, leaf);
517 printk("slot %d offset bad\n", i);
518 BUG_ON(1);
519 }
520 if (i == 0) {
521 if (btrfs_item_offset_nr(leaf, i) +
522 btrfs_item_size_nr(leaf, i) !=
523 BTRFS_LEAF_DATA_SIZE(root)) {
524 btrfs_print_leaf(root, leaf);
525 printk("slot %d first offset bad\n", i);
526 BUG_ON(1);
527 }
528 }
529 }
530 if (nritems > 0) {
531 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
532 btrfs_print_leaf(root, leaf);
533 printk("slot %d bad size \n", nritems - 1);
534 BUG_ON(1);
535 }
536 }
537 #endif
538 if (slot != 0 && slot < nritems - 1) {
539 btrfs_item_key(leaf, &leaf_key, slot);
540 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
541 if (comp_keys(&leaf_key, &cpukey) <= 0) {
542 btrfs_print_leaf(root, leaf);
543 printk("slot %d offset bad key\n", slot);
544 BUG_ON(1);
545 }
546 if (btrfs_item_offset_nr(leaf, slot - 1) !=
547 btrfs_item_end_nr(leaf, slot)) {
548 btrfs_print_leaf(root, leaf);
549 printk("slot %d offset bad\n", slot);
550 BUG_ON(1);
551 }
552 }
553 if (slot < nritems - 1) {
554 btrfs_item_key(leaf, &leaf_key, slot);
555 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
556 BUG_ON(comp_keys(&leaf_key, &cpukey) >= 0);
557 if (btrfs_item_offset_nr(leaf, slot) !=
558 btrfs_item_end_nr(leaf, slot + 1)) {
559 btrfs_print_leaf(root, leaf);
560 printk("slot %d offset bad\n", slot);
561 BUG_ON(1);
562 }
563 }
564 BUG_ON(btrfs_item_offset_nr(leaf, 0) +
565 btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
566 return 0;
567 }
568
569 static int noinline check_block(struct btrfs_root *root,
570 struct btrfs_path *path, int level)
571 {
572 return 0;
573 #if 0
574 struct extent_buffer *buf = path->nodes[level];
575
576 if (memcmp_extent_buffer(buf, root->fs_info->fsid,
577 (unsigned long)btrfs_header_fsid(buf),
578 BTRFS_FSID_SIZE)) {
579 printk("warning bad block %Lu\n", buf->start);
580 return 1;
581 }
582 #endif
583 if (level == 0)
584 return check_leaf(root, path, level);
585 return check_node(root, path, level);
586 }
587
588 /*
589 * search for key in the extent_buffer. The items start at offset p,
590 * and they are item_size apart. There are 'max' items in p.
591 *
592 * the slot in the array is returned via slot, and it points to
593 * the place where you would insert key if it is not found in
594 * the array.
595 *
596 * slot may point to max if the key is bigger than all of the keys
597 */
598 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
599 int item_size, struct btrfs_key *key,
600 int max, int *slot)
601 {
602 int low = 0;
603 int high = max;
604 int mid;
605 int ret;
606 struct btrfs_disk_key *tmp = NULL;
607 struct btrfs_disk_key unaligned;
608 unsigned long offset;
609 char *map_token = NULL;
610 char *kaddr = NULL;
611 unsigned long map_start = 0;
612 unsigned long map_len = 0;
613 int err;
614
615 while(low < high) {
616 mid = (low + high) / 2;
617 offset = p + mid * item_size;
618
619 if (!map_token || offset < map_start ||
620 (offset + sizeof(struct btrfs_disk_key)) >
621 map_start + map_len) {
622 if (map_token) {
623 unmap_extent_buffer(eb, map_token, KM_USER0);
624 map_token = NULL;
625 }
626 err = map_extent_buffer(eb, offset,
627 sizeof(struct btrfs_disk_key),
628 &map_token, &kaddr,
629 &map_start, &map_len, KM_USER0);
630
631 if (!err) {
632 tmp = (struct btrfs_disk_key *)(kaddr + offset -
633 map_start);
634 } else {
635 read_extent_buffer(eb, &unaligned,
636 offset, sizeof(unaligned));
637 tmp = &unaligned;
638 }
639
640 } else {
641 tmp = (struct btrfs_disk_key *)(kaddr + offset -
642 map_start);
643 }
644 ret = comp_keys(tmp, key);
645
646 if (ret < 0)
647 low = mid + 1;
648 else if (ret > 0)
649 high = mid;
650 else {
651 *slot = mid;
652 if (map_token)
653 unmap_extent_buffer(eb, map_token, KM_USER0);
654 return 0;
655 }
656 }
657 *slot = low;
658 if (map_token)
659 unmap_extent_buffer(eb, map_token, KM_USER0);
660 return 1;
661 }
662
663 /*
664 * simple bin_search frontend that does the right thing for
665 * leaves vs nodes
666 */
667 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
668 int level, int *slot)
669 {
670 if (level == 0) {
671 return generic_bin_search(eb,
672 offsetof(struct btrfs_leaf, items),
673 sizeof(struct btrfs_item),
674 key, btrfs_header_nritems(eb),
675 slot);
676 } else {
677 return generic_bin_search(eb,
678 offsetof(struct btrfs_node, ptrs),
679 sizeof(struct btrfs_key_ptr),
680 key, btrfs_header_nritems(eb),
681 slot);
682 }
683 return -1;
684 }
685
686 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
687 struct extent_buffer *parent, int slot)
688 {
689 if (slot < 0)
690 return NULL;
691 if (slot >= btrfs_header_nritems(parent))
692 return NULL;
693 return read_tree_block(root, btrfs_node_blockptr(parent, slot),
694 btrfs_level_size(root, btrfs_header_level(parent) - 1));
695 }
696
697 static int balance_level(struct btrfs_trans_handle *trans,
698 struct btrfs_root *root,
699 struct btrfs_path *path, int level)
700 {
701 struct extent_buffer *right = NULL;
702 struct extent_buffer *mid;
703 struct extent_buffer *left = NULL;
704 struct extent_buffer *parent = NULL;
705 int ret = 0;
706 int wret;
707 int pslot;
708 int orig_slot = path->slots[level];
709 int err_on_enospc = 0;
710 u64 orig_ptr;
711
712 if (level == 0)
713 return 0;
714
715 mid = path->nodes[level];
716 WARN_ON(btrfs_header_generation(mid) != trans->transid);
717
718 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
719
720 if (level < BTRFS_MAX_LEVEL - 1)
721 parent = path->nodes[level + 1];
722 pslot = path->slots[level + 1];
723
724 /*
725 * deal with the case where there is only one pointer in the root
726 * by promoting the node below to a root
727 */
728 if (!parent) {
729 struct extent_buffer *child;
730
731 if (btrfs_header_nritems(mid) != 1)
732 return 0;
733
734 /* promote the child to a root */
735 child = read_node_slot(root, mid, 0);
736 BUG_ON(!child);
737 ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
738 BUG_ON(ret);
739
740 root->node = child;
741 add_root_to_dirty_list(root);
742 path->nodes[level] = NULL;
743 clean_tree_block(trans, root, mid);
744 wait_on_tree_block_writeback(root, mid);
745 /* once for the path */
746 free_extent_buffer(mid);
747 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
748 root->root_key.objectid,
749 btrfs_header_generation(mid), 0, 0, 1);
750 /* once for the root ptr */
751 free_extent_buffer(mid);
752 return ret;
753 }
754 if (btrfs_header_nritems(mid) >
755 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
756 return 0;
757
758 if (btrfs_header_nritems(mid) < 2)
759 err_on_enospc = 1;
760
761 left = read_node_slot(root, parent, pslot - 1);
762 if (left) {
763 wret = btrfs_cow_block(trans, root, left,
764 parent, pslot - 1, &left);
765 if (wret) {
766 ret = wret;
767 goto enospc;
768 }
769 }
770 right = read_node_slot(root, parent, pslot + 1);
771 if (right) {
772 wret = btrfs_cow_block(trans, root, right,
773 parent, pslot + 1, &right);
774 if (wret) {
775 ret = wret;
776 goto enospc;
777 }
778 }
779
780 /* first, try to make some room in the middle buffer */
781 if (left) {
782 orig_slot += btrfs_header_nritems(left);
783 wret = push_node_left(trans, root, left, mid);
784 if (wret < 0)
785 ret = wret;
786 if (btrfs_header_nritems(mid) < 2)
787 err_on_enospc = 1;
788 }
789
790 /*
791 * then try to empty the right most buffer into the middle
792 */
793 if (right) {
794 wret = push_node_left(trans, root, mid, right);
795 if (wret < 0 && wret != -ENOSPC)
796 ret = wret;
797 if (btrfs_header_nritems(right) == 0) {
798 u64 bytenr = right->start;
799 u64 generation = btrfs_header_generation(parent);
800 u32 blocksize = right->len;
801
802 clean_tree_block(trans, root, right);
803 wait_on_tree_block_writeback(root, right);
804 free_extent_buffer(right);
805 right = NULL;
806 wret = del_ptr(trans, root, path, level + 1, pslot +
807 1);
808 if (wret)
809 ret = wret;
810 wret = btrfs_free_extent(trans, root, bytenr,
811 blocksize,
812 btrfs_header_owner(parent),
813 generation, 0, 0, 1);
814 if (wret)
815 ret = wret;
816 } else {
817 struct btrfs_disk_key right_key;
818 btrfs_node_key(right, &right_key, 0);
819 btrfs_set_node_key(parent, &right_key, pslot + 1);
820 btrfs_mark_buffer_dirty(parent);
821 }
822 }
823 if (btrfs_header_nritems(mid) == 1) {
824 /*
825 * we're not allowed to leave a node with one item in the
826 * tree during a delete. A deletion from lower in the tree
827 * could try to delete the only pointer in this node.
828 * So, pull some keys from the left.
829 * There has to be a left pointer at this point because
830 * otherwise we would have pulled some pointers from the
831 * right
832 */
833 BUG_ON(!left);
834 wret = balance_node_right(trans, root, mid, left);
835 if (wret < 0) {
836 ret = wret;
837 goto enospc;
838 }
839 BUG_ON(wret == 1);
840 }
841 if (btrfs_header_nritems(mid) == 0) {
842 /* we've managed to empty the middle node, drop it */
843 u64 root_gen = btrfs_header_generation(parent);
844 u64 bytenr = mid->start;
845 u32 blocksize = mid->len;
846 clean_tree_block(trans, root, mid);
847 wait_on_tree_block_writeback(root, mid);
848 free_extent_buffer(mid);
849 mid = NULL;
850 wret = del_ptr(trans, root, path, level + 1, pslot);
851 if (wret)
852 ret = wret;
853 wret = btrfs_free_extent(trans, root, bytenr, blocksize,
854 btrfs_header_owner(parent),
855 root_gen, 0, 0, 1);
856 if (wret)
857 ret = wret;
858 } else {
859 /* update the parent key to reflect our changes */
860 struct btrfs_disk_key mid_key;
861 btrfs_node_key(mid, &mid_key, 0);
862 btrfs_set_node_key(parent, &mid_key, pslot);
863 btrfs_mark_buffer_dirty(parent);
864 }
865
866 /* update the path */
867 if (left) {
868 if (btrfs_header_nritems(left) > orig_slot) {
869 extent_buffer_get(left);
870 path->nodes[level] = left;
871 path->slots[level + 1] -= 1;
872 path->slots[level] = orig_slot;
873 if (mid)
874 free_extent_buffer(mid);
875 } else {
876 orig_slot -= btrfs_header_nritems(left);
877 path->slots[level] = orig_slot;
878 }
879 }
880 /* double check we haven't messed things up */
881 check_block(root, path, level);
882 if (orig_ptr !=
883 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
884 BUG();
885 enospc:
886 if (right)
887 free_extent_buffer(right);
888 if (left)
889 free_extent_buffer(left);
890 return ret;
891 }
892
893 /* returns zero if the push worked, non-zero otherwise */
894 static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
895 struct btrfs_root *root,
896 struct btrfs_path *path, int level)
897 {
898 struct extent_buffer *right = NULL;
899 struct extent_buffer *mid;
900 struct extent_buffer *left = NULL;
901 struct extent_buffer *parent = NULL;
902 int ret = 0;
903 int wret;
904 int pslot;
905 int orig_slot = path->slots[level];
906 u64 orig_ptr;
907
908 if (level == 0)
909 return 1;
910
911 mid = path->nodes[level];
912 WARN_ON(btrfs_header_generation(mid) != trans->transid);
913 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
914
915 if (level < BTRFS_MAX_LEVEL - 1)
916 parent = path->nodes[level + 1];
917 pslot = path->slots[level + 1];
918
919 if (!parent)
920 return 1;
921
922 left = read_node_slot(root, parent, pslot - 1);
923
924 /* first, try to make some room in the middle buffer */
925 if (left) {
926 u32 left_nr;
927 left_nr = btrfs_header_nritems(left);
928 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
929 wret = 1;
930 } else {
931 ret = btrfs_cow_block(trans, root, left, parent,
932 pslot - 1, &left);
933 if (ret)
934 wret = 1;
935 else {
936 wret = push_node_left(trans, root,
937 left, mid);
938 }
939 }
940 if (wret < 0)
941 ret = wret;
942 if (wret == 0) {
943 struct btrfs_disk_key disk_key;
944 orig_slot += left_nr;
945 btrfs_node_key(mid, &disk_key, 0);
946 btrfs_set_node_key(parent, &disk_key, pslot);
947 btrfs_mark_buffer_dirty(parent);
948 if (btrfs_header_nritems(left) > orig_slot) {
949 path->nodes[level] = left;
950 path->slots[level + 1] -= 1;
951 path->slots[level] = orig_slot;
952 free_extent_buffer(mid);
953 } else {
954 orig_slot -=
955 btrfs_header_nritems(left);
956 path->slots[level] = orig_slot;
957 free_extent_buffer(left);
958 }
959 return 0;
960 }
961 free_extent_buffer(left);
962 }
963 right= read_node_slot(root, parent, pslot + 1);
964
965 /*
966 * then try to empty the right most buffer into the middle
967 */
968 if (right) {
969 u32 right_nr;
970 right_nr = btrfs_header_nritems(right);
971 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
972 wret = 1;
973 } else {
974 ret = btrfs_cow_block(trans, root, right,
975 parent, pslot + 1,
976 &right);
977 if (ret)
978 wret = 1;
979 else {
980 wret = balance_node_right(trans, root,
981 right, mid);
982 }
983 }
984 if (wret < 0)
985 ret = wret;
986 if (wret == 0) {
987 struct btrfs_disk_key disk_key;
988
989 btrfs_node_key(right, &disk_key, 0);
990 btrfs_set_node_key(parent, &disk_key, pslot + 1);
991 btrfs_mark_buffer_dirty(parent);
992
993 if (btrfs_header_nritems(mid) <= orig_slot) {
994 path->nodes[level] = right;
995 path->slots[level + 1] += 1;
996 path->slots[level] = orig_slot -
997 btrfs_header_nritems(mid);
998 free_extent_buffer(mid);
999 } else {
1000 free_extent_buffer(right);
1001 }
1002 return 0;
1003 }
1004 free_extent_buffer(right);
1005 }
1006 return 1;
1007 }
1008
1009 /*
1010 * readahead one full node of leaves
1011 */
1012 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
1013 int level, int slot, u64 objectid)
1014 {
1015 struct extent_buffer *node;
1016 struct btrfs_disk_key disk_key;
1017 u32 nritems;
1018 u64 search;
1019 u64 lowest_read;
1020 u64 highest_read;
1021 u64 nread = 0;
1022 int direction = path->reada;
1023 struct extent_buffer *eb;
1024 u32 nr;
1025 u32 blocksize;
1026 u32 nscan = 0;
1027
1028 if (level != 1)
1029 return;
1030
1031 if (!path->nodes[level])
1032 return;
1033
1034 node = path->nodes[level];
1035 search = btrfs_node_blockptr(node, slot);
1036 blocksize = btrfs_level_size(root, level - 1);
1037 eb = btrfs_find_tree_block(root, search, blocksize);
1038 if (eb) {
1039 free_extent_buffer(eb);
1040 return;
1041 }
1042
1043 highest_read = search;
1044 lowest_read = search;
1045
1046 nritems = btrfs_header_nritems(node);
1047 nr = slot;
1048 while(1) {
1049 if (direction < 0) {
1050 if (nr == 0)
1051 break;
1052 nr--;
1053 } else if (direction > 0) {
1054 nr++;
1055 if (nr >= nritems)
1056 break;
1057 }
1058 if (path->reada < 0 && objectid) {
1059 btrfs_node_key(node, &disk_key, nr);
1060 if (btrfs_disk_key_objectid(&disk_key) != objectid)
1061 break;
1062 }
1063 search = btrfs_node_blockptr(node, nr);
1064 if ((search >= lowest_read && search <= highest_read) ||
1065 (search < lowest_read && lowest_read - search <= 32768) ||
1066 (search > highest_read && search - highest_read <= 32768)) {
1067 readahead_tree_block(root, search, blocksize);
1068 nread += blocksize;
1069 }
1070 nscan++;
1071 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
1072 break;
1073 if(nread > (1024 * 1024) || nscan > 128)
1074 break;
1075
1076 if (search < lowest_read)
1077 lowest_read = search;
1078 if (search > highest_read)
1079 highest_read = search;
1080 }
1081 }
1082 /*
1083 * look for key in the tree. path is filled in with nodes along the way
1084 * if key is found, we return zero and you can find the item in the leaf
1085 * level of the path (level 0)
1086 *
1087 * If the key isn't found, the path points to the slot where it should
1088 * be inserted, and 1 is returned. If there are other errors during the
1089 * search a negative error number is returned.
1090 *
1091 * if ins_len > 0, nodes and leaves will be split as we walk down the
1092 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
1093 * possible)
1094 */
1095 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
1096 *root, struct btrfs_key *key, struct btrfs_path *p, int
1097 ins_len, int cow)
1098 {
1099 struct extent_buffer *b;
1100 u64 bytenr;
1101 u64 ptr_gen;
1102 int slot;
1103 int ret;
1104 int level;
1105 int should_reada = p->reada;
1106 u8 lowest_level = 0;
1107
1108 lowest_level = p->lowest_level;
1109 WARN_ON(lowest_level && ins_len);
1110 WARN_ON(p->nodes[0] != NULL);
1111 WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
1112 again:
1113 b = root->node;
1114 extent_buffer_get(b);
1115 while (b) {
1116 level = btrfs_header_level(b);
1117 if (cow) {
1118 int wret;
1119 wret = btrfs_cow_block(trans, root, b,
1120 p->nodes[level + 1],
1121 p->slots[level + 1],
1122 &b);
1123 if (wret) {
1124 free_extent_buffer(b);
1125 return wret;
1126 }
1127 }
1128 BUG_ON(!cow && ins_len);
1129 if (level != btrfs_header_level(b))
1130 WARN_ON(1);
1131 level = btrfs_header_level(b);
1132 p->nodes[level] = b;
1133 ret = check_block(root, p, level);
1134 if (ret)
1135 return -1;
1136 ret = bin_search(b, key, level, &slot);
1137 if (level != 0) {
1138 if (ret && slot > 0)
1139 slot -= 1;
1140 p->slots[level] = slot;
1141 if (ins_len > 0 && btrfs_header_nritems(b) >=
1142 BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1143 int sret = split_node(trans, root, p, level);
1144 BUG_ON(sret > 0);
1145 if (sret)
1146 return sret;
1147 b = p->nodes[level];
1148 slot = p->slots[level];
1149 } else if (ins_len < 0) {
1150 int sret = balance_level(trans, root, p,
1151 level);
1152 if (sret)
1153 return sret;
1154 b = p->nodes[level];
1155 if (!b) {
1156 btrfs_release_path(NULL, p);
1157 goto again;
1158 }
1159 slot = p->slots[level];
1160 BUG_ON(btrfs_header_nritems(b) == 1);
1161 }
1162 /* this is only true while dropping a snapshot */
1163 if (level == lowest_level)
1164 break;
1165 bytenr = btrfs_node_blockptr(b, slot);
1166 ptr_gen = btrfs_node_ptr_generation(b, slot);
1167 if (should_reada)
1168 reada_for_search(root, p, level, slot,
1169 key->objectid);
1170 b = read_tree_block(root, bytenr,
1171 btrfs_level_size(root, level - 1));
1172 if (ptr_gen != btrfs_header_generation(b)) {
1173 printk("block %llu bad gen wanted %llu "
1174 "found %llu\n",
1175 (unsigned long long)b->start,
1176 (unsigned long long)ptr_gen,
1177 (unsigned long long)btrfs_header_generation(b));
1178 }
1179 } else {
1180 p->slots[level] = slot;
1181 if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1182 sizeof(struct btrfs_item) + ins_len) {
1183 int sret = split_leaf(trans, root, key,
1184 p, ins_len, ret == 0);
1185 BUG_ON(sret > 0);
1186 if (sret)
1187 return sret;
1188 }
1189 return ret;
1190 }
1191 }
1192 return 1;
1193 }
1194
1195 /*
1196 * adjust the pointers going up the tree, starting at level
1197 * making sure the right key of each node is points to 'key'.
1198 * This is used after shifting pointers to the left, so it stops
1199 * fixing up pointers when a given leaf/node is not in slot 0 of the
1200 * higher levels
1201 *
1202 * If this fails to write a tree block, it returns -1, but continues
1203 * fixing up the blocks in ram so the tree is consistent.
1204 */
1205 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1206 struct btrfs_root *root, struct btrfs_path *path,
1207 struct btrfs_disk_key *key, int level)
1208 {
1209 int i;
1210 int ret = 0;
1211 struct extent_buffer *t;
1212
1213 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1214 int tslot = path->slots[i];
1215 if (!path->nodes[i])
1216 break;
1217 t = path->nodes[i];
1218 btrfs_set_node_key(t, key, tslot);
1219 btrfs_mark_buffer_dirty(path->nodes[i]);
1220 if (tslot != 0)
1221 break;
1222 }
1223 return ret;
1224 }
1225
1226 /*
1227 * try to push data from one node into the next node left in the
1228 * tree.
1229 *
1230 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1231 * error, and > 0 if there was no room in the left hand block.
1232 */
1233 static int push_node_left(struct btrfs_trans_handle *trans,
1234 struct btrfs_root *root, struct extent_buffer *dst,
1235 struct extent_buffer *src)
1236 {
1237 int push_items = 0;
1238 int src_nritems;
1239 int dst_nritems;
1240 int ret = 0;
1241
1242 src_nritems = btrfs_header_nritems(src);
1243 dst_nritems = btrfs_header_nritems(dst);
1244 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1245 WARN_ON(btrfs_header_generation(src) != trans->transid);
1246 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1247
1248 if (push_items <= 0) {
1249 return 1;
1250 }
1251
1252 if (src_nritems < push_items)
1253 push_items = src_nritems;
1254
1255 copy_extent_buffer(dst, src,
1256 btrfs_node_key_ptr_offset(dst_nritems),
1257 btrfs_node_key_ptr_offset(0),
1258 push_items * sizeof(struct btrfs_key_ptr));
1259
1260 if (push_items < src_nritems) {
1261 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1262 btrfs_node_key_ptr_offset(push_items),
1263 (src_nritems - push_items) *
1264 sizeof(struct btrfs_key_ptr));
1265 }
1266 btrfs_set_header_nritems(src, src_nritems - push_items);
1267 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1268 btrfs_mark_buffer_dirty(src);
1269 btrfs_mark_buffer_dirty(dst);
1270 return ret;
1271 }
1272
1273 /*
1274 * try to push data from one node into the next node right in the
1275 * tree.
1276 *
1277 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1278 * error, and > 0 if there was no room in the right hand block.
1279 *
1280 * this will only push up to 1/2 the contents of the left node over
1281 */
1282 static int balance_node_right(struct btrfs_trans_handle *trans,
1283 struct btrfs_root *root,
1284 struct extent_buffer *dst,
1285 struct extent_buffer *src)
1286 {
1287 int push_items = 0;
1288 int max_push;
1289 int src_nritems;
1290 int dst_nritems;
1291 int ret = 0;
1292
1293 WARN_ON(btrfs_header_generation(src) != trans->transid);
1294 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1295
1296 src_nritems = btrfs_header_nritems(src);
1297 dst_nritems = btrfs_header_nritems(dst);
1298 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1299 if (push_items <= 0)
1300 return 1;
1301
1302 max_push = src_nritems / 2 + 1;
1303 /* don't try to empty the node */
1304 if (max_push >= src_nritems)
1305 return 1;
1306
1307 if (max_push < push_items)
1308 push_items = max_push;
1309
1310 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1311 btrfs_node_key_ptr_offset(0),
1312 (dst_nritems) *
1313 sizeof(struct btrfs_key_ptr));
1314
1315 copy_extent_buffer(dst, src,
1316 btrfs_node_key_ptr_offset(0),
1317 btrfs_node_key_ptr_offset(src_nritems - push_items),
1318 push_items * sizeof(struct btrfs_key_ptr));
1319
1320 btrfs_set_header_nritems(src, src_nritems - push_items);
1321 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1322
1323 btrfs_mark_buffer_dirty(src);
1324 btrfs_mark_buffer_dirty(dst);
1325 return ret;
1326 }
1327
1328 /*
1329 * helper function to insert a new root level in the tree.
1330 * A new node is allocated, and a single item is inserted to
1331 * point to the existing root
1332 *
1333 * returns zero on success or < 0 on failure.
1334 */
1335 static int noinline insert_new_root(struct btrfs_trans_handle *trans,
1336 struct btrfs_root *root,
1337 struct btrfs_path *path, int level)
1338 {
1339 u64 root_gen;
1340 u64 lower_gen;
1341 struct extent_buffer *lower;
1342 struct extent_buffer *c;
1343 struct btrfs_disk_key lower_key;
1344
1345 BUG_ON(path->nodes[level]);
1346 BUG_ON(path->nodes[level-1] != root->node);
1347
1348 if (root->ref_cows)
1349 root_gen = trans->transid;
1350 else
1351 root_gen = 0;
1352
1353 lower = path->nodes[level-1];
1354 if (level == 1)
1355 btrfs_item_key(lower, &lower_key, 0);
1356 else
1357 btrfs_node_key(lower, &lower_key, 0);
1358
1359 c = __btrfs_alloc_free_block(trans, root, root->nodesize,
1360 root->root_key.objectid,
1361 root_gen, lower_key.objectid, level,
1362 root->node->start, 0);
1363 if (IS_ERR(c))
1364 return PTR_ERR(c);
1365 memset_extent_buffer(c, 0, 0, root->nodesize);
1366 btrfs_set_header_nritems(c, 1);
1367 btrfs_set_header_level(c, level);
1368 btrfs_set_header_bytenr(c, c->start);
1369 btrfs_set_header_generation(c, trans->transid);
1370 btrfs_set_header_owner(c, root->root_key.objectid);
1371
1372 write_extent_buffer(c, root->fs_info->fsid,
1373 (unsigned long)btrfs_header_fsid(c),
1374 BTRFS_FSID_SIZE);
1375 btrfs_set_node_key(c, &lower_key, 0);
1376 btrfs_set_node_blockptr(c, 0, lower->start);
1377 lower_gen = btrfs_header_generation(lower);
1378 WARN_ON(lower_gen == 0);
1379
1380 btrfs_set_node_ptr_generation(c, 0, lower_gen);
1381
1382 btrfs_mark_buffer_dirty(c);
1383
1384 /* the super has an extra ref to root->node */
1385 free_extent_buffer(root->node);
1386 root->node = c;
1387 add_root_to_dirty_list(root);
1388 extent_buffer_get(c);
1389 path->nodes[level] = c;
1390 path->slots[level] = 0;
1391
1392 if (root->ref_cows && lower_gen != trans->transid) {
1393 struct btrfs_path *back_path = btrfs_alloc_path();
1394 int ret;
1395 ret = btrfs_insert_extent_backref(trans,
1396 root->fs_info->extent_root,
1397 path, lower->start,
1398 root->root_key.objectid,
1399 trans->transid, 0, 0);
1400 BUG_ON(ret);
1401 btrfs_free_path(back_path);
1402 }
1403 return 0;
1404 }
1405
1406 /*
1407 * worker function to insert a single pointer in a node.
1408 * the node should have enough room for the pointer already
1409 *
1410 * slot and level indicate where you want the key to go, and
1411 * blocknr is the block the key points to.
1412 *
1413 * returns zero on success and < 0 on any error
1414 */
1415 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1416 *root, struct btrfs_path *path, struct btrfs_disk_key
1417 *key, u64 bytenr, int slot, int level)
1418 {
1419 struct extent_buffer *lower;
1420 int nritems;
1421
1422 BUG_ON(!path->nodes[level]);
1423 lower = path->nodes[level];
1424 nritems = btrfs_header_nritems(lower);
1425 if (slot > nritems)
1426 BUG();
1427 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1428 BUG();
1429 if (slot != nritems) {
1430 memmove_extent_buffer(lower,
1431 btrfs_node_key_ptr_offset(slot + 1),
1432 btrfs_node_key_ptr_offset(slot),
1433 (nritems - slot) * sizeof(struct btrfs_key_ptr));
1434 }
1435 btrfs_set_node_key(lower, key, slot);
1436 btrfs_set_node_blockptr(lower, slot, bytenr);
1437 WARN_ON(trans->transid == 0);
1438 btrfs_set_node_ptr_generation(lower, slot, trans->transid);
1439 btrfs_set_header_nritems(lower, nritems + 1);
1440 btrfs_mark_buffer_dirty(lower);
1441 return 0;
1442 }
1443
1444 /*
1445 * split the node at the specified level in path in two.
1446 * The path is corrected to point to the appropriate node after the split
1447 *
1448 * Before splitting this tries to make some room in the node by pushing
1449 * left and right, if either one works, it returns right away.
1450 *
1451 * returns 0 on success and < 0 on failure
1452 */
1453 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1454 *root, struct btrfs_path *path, int level)
1455 {
1456 u64 root_gen;
1457 struct extent_buffer *c;
1458 struct extent_buffer *split;
1459 struct btrfs_disk_key disk_key;
1460 int mid;
1461 int ret;
1462 int wret;
1463 u32 c_nritems;
1464
1465 c = path->nodes[level];
1466 WARN_ON(btrfs_header_generation(c) != trans->transid);
1467 if (c == root->node) {
1468 /* trying to split the root, lets make a new one */
1469 ret = insert_new_root(trans, root, path, level + 1);
1470 if (ret)
1471 return ret;
1472 } else {
1473 ret = push_nodes_for_insert(trans, root, path, level);
1474 c = path->nodes[level];
1475 if (!ret && btrfs_header_nritems(c) <
1476 BTRFS_NODEPTRS_PER_BLOCK(root) - 1)
1477 return 0;
1478 if (ret < 0)
1479 return ret;
1480 }
1481
1482 c_nritems = btrfs_header_nritems(c);
1483 if (root->ref_cows)
1484 root_gen = trans->transid;
1485 else
1486 root_gen = 0;
1487
1488 btrfs_node_key(c, &disk_key, 0);
1489 split = __btrfs_alloc_free_block(trans, root, root->nodesize,
1490 root->root_key.objectid,
1491 root_gen,
1492 btrfs_disk_key_objectid(&disk_key),
1493 level, c->start, 0);
1494 if (IS_ERR(split))
1495 return PTR_ERR(split);
1496
1497 btrfs_set_header_flags(split, btrfs_header_flags(c));
1498 btrfs_set_header_level(split, btrfs_header_level(c));
1499 btrfs_set_header_bytenr(split, split->start);
1500 btrfs_set_header_generation(split, trans->transid);
1501 btrfs_set_header_owner(split, root->root_key.objectid);
1502 btrfs_set_header_flags(split, 0);
1503 write_extent_buffer(split, root->fs_info->fsid,
1504 (unsigned long)btrfs_header_fsid(split),
1505 BTRFS_FSID_SIZE);
1506
1507 mid = (c_nritems + 1) / 2;
1508
1509 copy_extent_buffer(split, c,
1510 btrfs_node_key_ptr_offset(0),
1511 btrfs_node_key_ptr_offset(mid),
1512 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1513 btrfs_set_header_nritems(split, c_nritems - mid);
1514 btrfs_set_header_nritems(c, mid);
1515 ret = 0;
1516
1517 btrfs_mark_buffer_dirty(c);
1518 btrfs_mark_buffer_dirty(split);
1519
1520 btrfs_node_key(split, &disk_key, 0);
1521 wret = insert_ptr(trans, root, path, &disk_key, split->start,
1522 path->slots[level + 1] + 1,
1523 level + 1);
1524 if (wret)
1525 ret = wret;
1526
1527 if (path->slots[level] >= mid) {
1528 path->slots[level] -= mid;
1529 free_extent_buffer(c);
1530 path->nodes[level] = split;
1531 path->slots[level + 1] += 1;
1532 } else {
1533 free_extent_buffer(split);
1534 }
1535 return ret;
1536 }
1537
1538 /*
1539 * how many bytes are required to store the items in a leaf. start
1540 * and nr indicate which items in the leaf to check. This totals up the
1541 * space used both by the item structs and the item data
1542 */
1543 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1544 {
1545 int data_len;
1546 int nritems = btrfs_header_nritems(l);
1547 int end = min(nritems, start + nr) - 1;
1548
1549 if (!nr)
1550 return 0;
1551 data_len = btrfs_item_end_nr(l, start);
1552 data_len = data_len - btrfs_item_offset_nr(l, end);
1553 data_len += sizeof(struct btrfs_item) * nr;
1554 WARN_ON(data_len < 0);
1555 return data_len;
1556 }
1557
1558 /*
1559 * The space between the end of the leaf items and
1560 * the start of the leaf data. IOW, how much room
1561 * the leaf has left for both items and data
1562 */
1563 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1564 {
1565 int nritems = btrfs_header_nritems(leaf);
1566 int ret;
1567 ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1568 if (ret < 0) {
1569 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1570 ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
1571 leaf_space_used(leaf, 0, nritems), nritems);
1572 }
1573 return ret;
1574 }
1575
1576 /*
1577 * push some data in the path leaf to the right, trying to free up at
1578 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1579 *
1580 * returns 1 if the push failed because the other node didn't have enough
1581 * room, 0 if everything worked out and < 0 if there were major errors.
1582 */
1583 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1584 *root, struct btrfs_path *path, int data_size,
1585 int empty)
1586 {
1587 struct extent_buffer *left = path->nodes[0];
1588 struct extent_buffer *right;
1589 struct extent_buffer *upper;
1590 struct btrfs_disk_key disk_key;
1591 int slot;
1592 u32 i;
1593 int free_space;
1594 int push_space = 0;
1595 int push_items = 0;
1596 struct btrfs_item *item;
1597 u32 left_nritems;
1598 u32 nr;
1599 u32 right_nritems;
1600 u32 data_end;
1601 u32 this_item_size;
1602 int ret;
1603
1604 slot = path->slots[1];
1605 if (!path->nodes[1]) {
1606 return 1;
1607 }
1608 upper = path->nodes[1];
1609 if (slot >= btrfs_header_nritems(upper) - 1)
1610 return 1;
1611
1612 right = read_tree_block(root, btrfs_node_blockptr(upper, slot + 1),
1613 root->leafsize);
1614 free_space = btrfs_leaf_free_space(root, right);
1615 if (free_space < data_size + sizeof(struct btrfs_item)) {
1616 free_extent_buffer(right);
1617 return 1;
1618 }
1619
1620 /* cow and double check */
1621 ret = btrfs_cow_block(trans, root, right, upper,
1622 slot + 1, &right);
1623 if (ret) {
1624 free_extent_buffer(right);
1625 return 1;
1626 }
1627 free_space = btrfs_leaf_free_space(root, right);
1628 if (free_space < data_size + sizeof(struct btrfs_item)) {
1629 free_extent_buffer(right);
1630 return 1;
1631 }
1632
1633 left_nritems = btrfs_header_nritems(left);
1634 if (left_nritems == 0) {
1635 free_extent_buffer(right);
1636 return 1;
1637 }
1638
1639 if (empty)
1640 nr = 0;
1641 else
1642 nr = 1;
1643
1644 i = left_nritems - 1;
1645 while (i >= nr) {
1646 item = btrfs_item_nr(left, i);
1647
1648 if (path->slots[0] == i)
1649 push_space += data_size + sizeof(*item);
1650
1651 if (!left->map_token) {
1652 map_extent_buffer(left, (unsigned long)item,
1653 sizeof(struct btrfs_item),
1654 &left->map_token, &left->kaddr,
1655 &left->map_start, &left->map_len,
1656 KM_USER1);
1657 }
1658
1659 this_item_size = btrfs_item_size(left, item);
1660 if (this_item_size + sizeof(*item) + push_space > free_space)
1661 break;
1662 push_items++;
1663 push_space += this_item_size + sizeof(*item);
1664 if (i == 0)
1665 break;
1666 i--;
1667 }
1668 if (left->map_token) {
1669 unmap_extent_buffer(left, left->map_token, KM_USER1);
1670 left->map_token = NULL;
1671 }
1672
1673 if (push_items == 0) {
1674 free_extent_buffer(right);
1675 return 1;
1676 }
1677
1678 if (!empty && push_items == left_nritems)
1679 WARN_ON(1);
1680
1681 /* push left to right */
1682 right_nritems = btrfs_header_nritems(right);
1683
1684 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1685 push_space -= leaf_data_end(root, left);
1686
1687 /* make room in the right data area */
1688 data_end = leaf_data_end(root, right);
1689 memmove_extent_buffer(right,
1690 btrfs_leaf_data(right) + data_end - push_space,
1691 btrfs_leaf_data(right) + data_end,
1692 BTRFS_LEAF_DATA_SIZE(root) - data_end);
1693
1694 /* copy from the left data area */
1695 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1696 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1697 btrfs_leaf_data(left) + leaf_data_end(root, left),
1698 push_space);
1699
1700 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1701 btrfs_item_nr_offset(0),
1702 right_nritems * sizeof(struct btrfs_item));
1703
1704 /* copy the items from left to right */
1705 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1706 btrfs_item_nr_offset(left_nritems - push_items),
1707 push_items * sizeof(struct btrfs_item));
1708
1709 /* update the item pointers */
1710 right_nritems += push_items;
1711 btrfs_set_header_nritems(right, right_nritems);
1712 push_space = BTRFS_LEAF_DATA_SIZE(root);
1713 for (i = 0; i < right_nritems; i++) {
1714 item = btrfs_item_nr(right, i);
1715 if (!right->map_token) {
1716 map_extent_buffer(right, (unsigned long)item,
1717 sizeof(struct btrfs_item),
1718 &right->map_token, &right->kaddr,
1719 &right->map_start, &right->map_len,
1720 KM_USER1);
1721 }
1722 push_space -= btrfs_item_size(right, item);
1723 btrfs_set_item_offset(right, item, push_space);
1724 }
1725
1726 if (right->map_token) {
1727 unmap_extent_buffer(right, right->map_token, KM_USER1);
1728 right->map_token = NULL;
1729 }
1730 left_nritems -= push_items;
1731 btrfs_set_header_nritems(left, left_nritems);
1732
1733 if (left_nritems)
1734 btrfs_mark_buffer_dirty(left);
1735 btrfs_mark_buffer_dirty(right);
1736
1737 btrfs_item_key(right, &disk_key, 0);
1738 btrfs_set_node_key(upper, &disk_key, slot + 1);
1739 btrfs_mark_buffer_dirty(upper);
1740
1741 /* then fixup the leaf pointer in the path */
1742 if (path->slots[0] >= left_nritems) {
1743 path->slots[0] -= left_nritems;
1744 free_extent_buffer(path->nodes[0]);
1745 path->nodes[0] = right;
1746 path->slots[1] += 1;
1747 } else {
1748 free_extent_buffer(right);
1749 }
1750 return 0;
1751 }
1752 /*
1753 * push some data in the path leaf to the left, trying to free up at
1754 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1755 */
1756 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1757 *root, struct btrfs_path *path, int data_size,
1758 int empty)
1759 {
1760 struct btrfs_disk_key disk_key;
1761 struct extent_buffer *right = path->nodes[0];
1762 struct extent_buffer *left;
1763 int slot;
1764 int i;
1765 int free_space;
1766 int push_space = 0;
1767 int push_items = 0;
1768 struct btrfs_item *item;
1769 u32 old_left_nritems;
1770 u32 right_nritems;
1771 u32 nr;
1772 int ret = 0;
1773 int wret;
1774 u32 this_item_size;
1775 u32 old_left_item_size;
1776
1777 slot = path->slots[1];
1778 if (slot == 0)
1779 return 1;
1780 if (!path->nodes[1])
1781 return 1;
1782
1783 right_nritems = btrfs_header_nritems(right);
1784 if (right_nritems == 0) {
1785 return 1;
1786 }
1787
1788 left = read_tree_block(root, btrfs_node_blockptr(path->nodes[1],
1789 slot - 1), root->leafsize);
1790 free_space = btrfs_leaf_free_space(root, left);
1791 if (free_space < data_size + sizeof(struct btrfs_item)) {
1792 free_extent_buffer(left);
1793 return 1;
1794 }
1795
1796 /* cow and double check */
1797 ret = btrfs_cow_block(trans, root, left,
1798 path->nodes[1], slot - 1, &left);
1799 if (ret) {
1800 /* we hit -ENOSPC, but it isn't fatal here */
1801 free_extent_buffer(left);
1802 return 1;
1803 }
1804
1805 free_space = btrfs_leaf_free_space(root, left);
1806 if (free_space < data_size + sizeof(struct btrfs_item)) {
1807 free_extent_buffer(left);
1808 return 1;
1809 }
1810
1811 if (empty)
1812 nr = right_nritems;
1813 else
1814 nr = right_nritems - 1;
1815
1816 for (i = 0; i < nr; i++) {
1817 item = btrfs_item_nr(right, i);
1818 if (!right->map_token) {
1819 map_extent_buffer(right, (unsigned long)item,
1820 sizeof(struct btrfs_item),
1821 &right->map_token, &right->kaddr,
1822 &right->map_start, &right->map_len,
1823 KM_USER1);
1824 }
1825
1826 if (path->slots[0] == i)
1827 push_space += data_size + sizeof(*item);
1828
1829 this_item_size = btrfs_item_size(right, item);
1830 if (this_item_size + sizeof(*item) + push_space > free_space)
1831 break;
1832
1833 push_items++;
1834 push_space += this_item_size + sizeof(*item);
1835 }
1836
1837 if (right->map_token) {
1838 unmap_extent_buffer(right, right->map_token, KM_USER1);
1839 right->map_token = NULL;
1840 }
1841
1842 if (push_items == 0) {
1843 free_extent_buffer(left);
1844 return 1;
1845 }
1846 if (!empty && push_items == btrfs_header_nritems(right))
1847 WARN_ON(1);
1848
1849 /* push data from right to left */
1850 copy_extent_buffer(left, right,
1851 btrfs_item_nr_offset(btrfs_header_nritems(left)),
1852 btrfs_item_nr_offset(0),
1853 push_items * sizeof(struct btrfs_item));
1854
1855 push_space = BTRFS_LEAF_DATA_SIZE(root) -
1856 btrfs_item_offset_nr(right, push_items -1);
1857
1858 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
1859 leaf_data_end(root, left) - push_space,
1860 btrfs_leaf_data(right) +
1861 btrfs_item_offset_nr(right, push_items - 1),
1862 push_space);
1863 old_left_nritems = btrfs_header_nritems(left);
1864 BUG_ON(old_left_nritems < 0);
1865
1866 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
1867 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1868 u32 ioff;
1869
1870 item = btrfs_item_nr(left, i);
1871 if (!left->map_token) {
1872 map_extent_buffer(left, (unsigned long)item,
1873 sizeof(struct btrfs_item),
1874 &left->map_token, &left->kaddr,
1875 &left->map_start, &left->map_len,
1876 KM_USER1);
1877 }
1878
1879 ioff = btrfs_item_offset(left, item);
1880 btrfs_set_item_offset(left, item,
1881 ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
1882 }
1883 btrfs_set_header_nritems(left, old_left_nritems + push_items);
1884 if (left->map_token) {
1885 unmap_extent_buffer(left, left->map_token, KM_USER1);
1886 left->map_token = NULL;
1887 }
1888
1889 /* fixup right node */
1890 if (push_items > right_nritems) {
1891 printk("push items %d nr %u\n", push_items, right_nritems);
1892 WARN_ON(1);
1893 }
1894
1895 if (push_items < right_nritems) {
1896 push_space = btrfs_item_offset_nr(right, push_items - 1) -
1897 leaf_data_end(root, right);
1898 memmove_extent_buffer(right, btrfs_leaf_data(right) +
1899 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1900 btrfs_leaf_data(right) +
1901 leaf_data_end(root, right), push_space);
1902
1903 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
1904 btrfs_item_nr_offset(push_items),
1905 (btrfs_header_nritems(right) - push_items) *
1906 sizeof(struct btrfs_item));
1907 }
1908 right_nritems -= push_items;
1909 btrfs_set_header_nritems(right, right_nritems);
1910 push_space = BTRFS_LEAF_DATA_SIZE(root);
1911 for (i = 0; i < right_nritems; i++) {
1912 item = btrfs_item_nr(right, i);
1913
1914 if (!right->map_token) {
1915 map_extent_buffer(right, (unsigned long)item,
1916 sizeof(struct btrfs_item),
1917 &right->map_token, &right->kaddr,
1918 &right->map_start, &right->map_len,
1919 KM_USER1);
1920 }
1921
1922 push_space = push_space - btrfs_item_size(right, item);
1923 btrfs_set_item_offset(right, item, push_space);
1924 }
1925 if (right->map_token) {
1926 unmap_extent_buffer(right, right->map_token, KM_USER1);
1927 right->map_token = NULL;
1928 }
1929
1930 btrfs_mark_buffer_dirty(left);
1931 if (right_nritems)
1932 btrfs_mark_buffer_dirty(right);
1933
1934 btrfs_item_key(right, &disk_key, 0);
1935 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1936 if (wret)
1937 ret = wret;
1938
1939 /* then fixup the leaf pointer in the path */
1940 if (path->slots[0] < push_items) {
1941 path->slots[0] += old_left_nritems;
1942 free_extent_buffer(path->nodes[0]);
1943 path->nodes[0] = left;
1944 path->slots[1] -= 1;
1945 } else {
1946 free_extent_buffer(left);
1947 path->slots[0] -= push_items;
1948 }
1949 BUG_ON(path->slots[0] < 0);
1950 return ret;
1951 }
1952
1953 /*
1954 * split the path's leaf in two, making sure there is at least data_size
1955 * available for the resulting leaf level of the path.
1956 *
1957 * returns 0 if all went well and < 0 on failure.
1958 */
1959 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1960 *root, struct btrfs_key *ins_key,
1961 struct btrfs_path *path, int data_size, int extend)
1962 {
1963 u64 root_gen;
1964 struct extent_buffer *l;
1965 u32 nritems;
1966 int mid;
1967 int slot;
1968 struct extent_buffer *right;
1969 int space_needed = data_size + sizeof(struct btrfs_item);
1970 int data_copy_size;
1971 int rt_data_off;
1972 int i;
1973 int ret = 0;
1974 int wret;
1975 int double_split;
1976 int num_doubles = 0;
1977 struct btrfs_disk_key disk_key;
1978
1979 if (extend)
1980 space_needed = data_size;
1981
1982 if (root->ref_cows)
1983 root_gen = trans->transid;
1984 else
1985 root_gen = 0;
1986
1987 /* first try to make some room by pushing left and right */
1988 if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
1989 wret = push_leaf_right(trans, root, path, data_size, 0);
1990 if (wret < 0) {
1991 return wret;
1992 }
1993 if (wret) {
1994 wret = push_leaf_left(trans, root, path, data_size, 0);
1995 if (wret < 0)
1996 return wret;
1997 }
1998 l = path->nodes[0];
1999
2000 /* did the pushes work? */
2001 if (btrfs_leaf_free_space(root, l) >= space_needed)
2002 return 0;
2003 }
2004
2005 if (!path->nodes[1]) {
2006 ret = insert_new_root(trans, root, path, 1);
2007 if (ret)
2008 return ret;
2009 }
2010 again:
2011 double_split = 0;
2012 l = path->nodes[0];
2013 slot = path->slots[0];
2014 nritems = btrfs_header_nritems(l);
2015 mid = (nritems + 1)/ 2;
2016
2017 btrfs_item_key(l, &disk_key, 0);
2018
2019 right = __btrfs_alloc_free_block(trans, root, root->leafsize,
2020 root->root_key.objectid,
2021 root_gen, disk_key.objectid, 0,
2022 l->start, 0);
2023 if (IS_ERR(right)) {
2024 BUG_ON(1);
2025 return PTR_ERR(right);
2026 }
2027
2028 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
2029 btrfs_set_header_bytenr(right, right->start);
2030 btrfs_set_header_generation(right, trans->transid);
2031 btrfs_set_header_owner(right, root->root_key.objectid);
2032 btrfs_set_header_level(right, 0);
2033 write_extent_buffer(right, root->fs_info->fsid,
2034 (unsigned long)btrfs_header_fsid(right),
2035 BTRFS_FSID_SIZE);
2036 if (mid <= slot) {
2037 if (nritems == 1 ||
2038 leaf_space_used(l, mid, nritems - mid) + space_needed >
2039 BTRFS_LEAF_DATA_SIZE(root)) {
2040 if (slot >= nritems) {
2041 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2042 btrfs_set_header_nritems(right, 0);
2043 wret = insert_ptr(trans, root, path,
2044 &disk_key, right->start,
2045 path->slots[1] + 1, 1);
2046 if (wret)
2047 ret = wret;
2048 free_extent_buffer(path->nodes[0]);
2049 path->nodes[0] = right;
2050 path->slots[0] = 0;
2051 path->slots[1] += 1;
2052 btrfs_mark_buffer_dirty(right);
2053 return ret;
2054 }
2055 mid = slot;
2056 if (mid != nritems &&
2057 leaf_space_used(l, mid, nritems - mid) +
2058 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2059 double_split = 1;
2060 }
2061 }
2062 } else {
2063 if (leaf_space_used(l, 0, mid + 1) + space_needed >
2064 BTRFS_LEAF_DATA_SIZE(root)) {
2065 if (!extend && slot == 0) {
2066 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2067 btrfs_set_header_nritems(right, 0);
2068 wret = insert_ptr(trans, root, path,
2069 &disk_key,
2070 right->start,
2071 path->slots[1], 1);
2072 if (wret)
2073 ret = wret;
2074 free_extent_buffer(path->nodes[0]);
2075 path->nodes[0] = right;
2076 path->slots[0] = 0;
2077 if (path->slots[1] == 0) {
2078 wret = fixup_low_keys(trans, root,
2079 path, &disk_key, 1);
2080 if (wret)
2081 ret = wret;
2082 }
2083 btrfs_mark_buffer_dirty(right);
2084 return ret;
2085 } else if (extend && slot == 0) {
2086 mid = 1;
2087 } else {
2088 mid = slot;
2089 if (mid != nritems &&
2090 leaf_space_used(l, mid, nritems - mid) +
2091 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2092 double_split = 1;
2093 }
2094 }
2095 }
2096 }
2097 nritems = nritems - mid;
2098 btrfs_set_header_nritems(right, nritems);
2099 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
2100
2101 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
2102 btrfs_item_nr_offset(mid),
2103 nritems * sizeof(struct btrfs_item));
2104
2105 copy_extent_buffer(right, l,
2106 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
2107 data_copy_size, btrfs_leaf_data(l) +
2108 leaf_data_end(root, l), data_copy_size);
2109
2110 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
2111 btrfs_item_end_nr(l, mid);
2112
2113 for (i = 0; i < nritems; i++) {
2114 struct btrfs_item *item = btrfs_item_nr(right, i);
2115 u32 ioff;
2116
2117 if (!right->map_token) {
2118 map_extent_buffer(right, (unsigned long)item,
2119 sizeof(struct btrfs_item),
2120 &right->map_token, &right->kaddr,
2121 &right->map_start, &right->map_len,
2122 KM_USER1);
2123 }
2124
2125 ioff = btrfs_item_offset(right, item);
2126 btrfs_set_item_offset(right, item, ioff + rt_data_off);
2127 }
2128
2129 if (right->map_token) {
2130 unmap_extent_buffer(right, right->map_token, KM_USER1);
2131 right->map_token = NULL;
2132 }
2133
2134 btrfs_set_header_nritems(l, mid);
2135 ret = 0;
2136 btrfs_item_key(right, &disk_key, 0);
2137 wret = insert_ptr(trans, root, path, &disk_key, right->start,
2138 path->slots[1] + 1, 1);
2139 if (wret)
2140 ret = wret;
2141
2142 btrfs_mark_buffer_dirty(right);
2143 btrfs_mark_buffer_dirty(l);
2144 BUG_ON(path->slots[0] != slot);
2145
2146 if (mid <= slot) {
2147 free_extent_buffer(path->nodes[0]);
2148 path->nodes[0] = right;
2149 path->slots[0] -= mid;
2150 path->slots[1] += 1;
2151 } else
2152 free_extent_buffer(right);
2153
2154 BUG_ON(path->slots[0] < 0);
2155
2156 if (double_split) {
2157 BUG_ON(num_doubles != 0);
2158 num_doubles++;
2159 goto again;
2160 }
2161 return ret;
2162 }
2163
2164 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
2165 struct btrfs_root *root,
2166 struct btrfs_path *path,
2167 u32 new_size, int from_end)
2168 {
2169 int ret = 0;
2170 int slot;
2171 int slot_orig;
2172 struct extent_buffer *leaf;
2173 struct btrfs_item *item;
2174 u32 nritems;
2175 unsigned int data_end;
2176 unsigned int old_data_start;
2177 unsigned int old_size;
2178 unsigned int size_diff;
2179 int i;
2180
2181 slot_orig = path->slots[0];
2182 leaf = path->nodes[0];
2183 slot = path->slots[0];
2184
2185 old_size = btrfs_item_size_nr(leaf, slot);
2186 if (old_size == new_size)
2187 return 0;
2188
2189 nritems = btrfs_header_nritems(leaf);
2190 data_end = leaf_data_end(root, leaf);
2191
2192 old_data_start = btrfs_item_offset_nr(leaf, slot);
2193
2194 size_diff = old_size - new_size;
2195
2196 BUG_ON(slot < 0);
2197 BUG_ON(slot >= nritems);
2198
2199 /*
2200 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2201 */
2202 /* first correct the data pointers */
2203 for (i = slot; i < nritems; i++) {
2204 u32 ioff;
2205 item = btrfs_item_nr(leaf, i);
2206
2207 if (!leaf->map_token) {
2208 map_extent_buffer(leaf, (unsigned long)item,
2209 sizeof(struct btrfs_item),
2210 &leaf->map_token, &leaf->kaddr,
2211 &leaf->map_start, &leaf->map_len,
2212 KM_USER1);
2213 }
2214
2215 ioff = btrfs_item_offset(leaf, item);
2216 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2217 }
2218
2219 if (leaf->map_token) {
2220 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2221 leaf->map_token = NULL;
2222 }
2223
2224 /* shift the data */
2225 if (from_end) {
2226 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2227 data_end + size_diff, btrfs_leaf_data(leaf) +
2228 data_end, old_data_start + new_size - data_end);
2229 } else {
2230 struct btrfs_disk_key disk_key;
2231 u64 offset;
2232
2233 btrfs_item_key(leaf, &disk_key, slot);
2234
2235 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2236 unsigned long ptr;
2237 struct btrfs_file_extent_item *fi;
2238
2239 fi = btrfs_item_ptr(leaf, slot,
2240 struct btrfs_file_extent_item);
2241 fi = (struct btrfs_file_extent_item *)(
2242 (unsigned long)fi - size_diff);
2243
2244 if (btrfs_file_extent_type(leaf, fi) ==
2245 BTRFS_FILE_EXTENT_INLINE) {
2246 ptr = btrfs_item_ptr_offset(leaf, slot);
2247 memmove_extent_buffer(leaf, ptr,
2248 (unsigned long)fi,
2249 offsetof(struct btrfs_file_extent_item,
2250 disk_bytenr));
2251 }
2252 }
2253
2254 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2255 data_end + size_diff, btrfs_leaf_data(leaf) +
2256 data_end, old_data_start - data_end);
2257
2258 offset = btrfs_disk_key_offset(&disk_key);
2259 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2260 btrfs_set_item_key(leaf, &disk_key, slot);
2261 if (slot == 0)
2262 fixup_low_keys(trans, root, path, &disk_key, 1);
2263 }
2264
2265 item = btrfs_item_nr(leaf, slot);
2266 btrfs_set_item_size(leaf, item, new_size);
2267 btrfs_mark_buffer_dirty(leaf);
2268
2269 ret = 0;
2270 if (btrfs_leaf_free_space(root, leaf) < 0) {
2271 btrfs_print_leaf(root, leaf);
2272 BUG();
2273 }
2274 return ret;
2275 }
2276
2277 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2278 struct btrfs_root *root, struct btrfs_path *path,
2279 u32 data_size)
2280 {
2281 int ret = 0;
2282 int slot;
2283 int slot_orig;
2284 struct extent_buffer *leaf;
2285 struct btrfs_item *item;
2286 u32 nritems;
2287 unsigned int data_end;
2288 unsigned int old_data;
2289 unsigned int old_size;
2290 int i;
2291
2292 slot_orig = path->slots[0];
2293 leaf = path->nodes[0];
2294
2295 nritems = btrfs_header_nritems(leaf);
2296 data_end = leaf_data_end(root, leaf);
2297
2298 if (btrfs_leaf_free_space(root, leaf) < data_size) {
2299 btrfs_print_leaf(root, leaf);
2300 BUG();
2301 }
2302 slot = path->slots[0];
2303 old_data = btrfs_item_end_nr(leaf, slot);
2304
2305 BUG_ON(slot < 0);
2306 if (slot >= nritems) {
2307 btrfs_print_leaf(root, leaf);
2308 printk("slot %d too large, nritems %d\n", slot, nritems);
2309 BUG_ON(1);
2310 }
2311
2312 /*
2313 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2314 */
2315 /* first correct the data pointers */
2316 for (i = slot; i < nritems; i++) {
2317 u32 ioff;
2318 item = btrfs_item_nr(leaf, i);
2319
2320 if (!leaf->map_token) {
2321 map_extent_buffer(leaf, (unsigned long)item,
2322 sizeof(struct btrfs_item),
2323 &leaf->map_token, &leaf->kaddr,
2324 &leaf->map_start, &leaf->map_len,
2325 KM_USER1);
2326 }
2327 ioff = btrfs_item_offset(leaf, item);
2328 btrfs_set_item_offset(leaf, item, ioff - data_size);
2329 }
2330
2331 if (leaf->map_token) {
2332 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2333 leaf->map_token = NULL;
2334 }
2335
2336 /* shift the data */
2337 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2338 data_end - data_size, btrfs_leaf_data(leaf) +
2339 data_end, old_data - data_end);
2340
2341 data_end = old_data;
2342 old_size = btrfs_item_size_nr(leaf, slot);
2343 item = btrfs_item_nr(leaf, slot);
2344 btrfs_set_item_size(leaf, item, old_size + data_size);
2345 btrfs_mark_buffer_dirty(leaf);
2346
2347 ret = 0;
2348 if (btrfs_leaf_free_space(root, leaf) < 0) {
2349 btrfs_print_leaf(root, leaf);
2350 BUG();
2351 }
2352 return ret;
2353 }
2354
2355 /*
2356 * Given a key and some data, insert an item into the tree.
2357 * This does all the path init required, making room in the tree if needed.
2358 */
2359 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
2360 struct btrfs_root *root,
2361 struct btrfs_path *path,
2362 struct btrfs_key *cpu_key, u32 *data_size,
2363 int nr)
2364 {
2365 struct extent_buffer *leaf;
2366 struct btrfs_item *item;
2367 int ret = 0;
2368 int slot;
2369 int slot_orig;
2370 int i;
2371 u32 nritems;
2372 u32 total_size = 0;
2373 u32 total_data = 0;
2374 unsigned int data_end;
2375 struct btrfs_disk_key disk_key;
2376
2377 for (i = 0; i < nr; i++) {
2378 total_data += data_size[i];
2379 }
2380
2381 /* create a root if there isn't one */
2382 if (!root->node)
2383 BUG();
2384
2385 total_size = total_data + (nr - 1) * sizeof(struct btrfs_item);
2386 ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
2387 if (ret == 0) {
2388 return -EEXIST;
2389 }
2390 if (ret < 0)
2391 goto out;
2392
2393 slot_orig = path->slots[0];
2394 leaf = path->nodes[0];
2395
2396 nritems = btrfs_header_nritems(leaf);
2397 data_end = leaf_data_end(root, leaf);
2398
2399 if (btrfs_leaf_free_space(root, leaf) <
2400 sizeof(struct btrfs_item) + total_size) {
2401 btrfs_print_leaf(root, leaf);
2402 printk("not enough freespace need %u have %d\n",
2403 total_size, btrfs_leaf_free_space(root, leaf));
2404 BUG();
2405 }
2406
2407 slot = path->slots[0];
2408 BUG_ON(slot < 0);
2409
2410 if (slot != nritems) {
2411 int i;
2412 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2413
2414 if (old_data < data_end) {
2415 btrfs_print_leaf(root, leaf);
2416 printk("slot %d old_data %d data_end %d\n",
2417 slot, old_data, data_end);
2418 BUG_ON(1);
2419 }
2420 /*
2421 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2422 */
2423 /* first correct the data pointers */
2424 WARN_ON(leaf->map_token);
2425 for (i = slot; i < nritems; i++) {
2426 u32 ioff;
2427
2428 item = btrfs_item_nr(leaf, i);
2429 if (!leaf->map_token) {
2430 map_extent_buffer(leaf, (unsigned long)item,
2431 sizeof(struct btrfs_item),
2432 &leaf->map_token, &leaf->kaddr,
2433 &leaf->map_start, &leaf->map_len,
2434 KM_USER1);
2435 }
2436
2437 ioff = btrfs_item_offset(leaf, item);
2438 btrfs_set_item_offset(leaf, item, ioff - total_data);
2439 }
2440 if (leaf->map_token) {
2441 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2442 leaf->map_token = NULL;
2443 }
2444
2445 /* shift the items */
2446 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
2447 btrfs_item_nr_offset(slot),
2448 (nritems - slot) * sizeof(struct btrfs_item));
2449
2450 /* shift the data */
2451 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2452 data_end - total_data, btrfs_leaf_data(leaf) +
2453 data_end, old_data - data_end);
2454 data_end = old_data;
2455 }
2456
2457 /* setup the item for the new data */
2458 for (i = 0; i < nr; i++) {
2459 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
2460 btrfs_set_item_key(leaf, &disk_key, slot + i);
2461 item = btrfs_item_nr(leaf, slot + i);
2462 btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
2463 data_end -= data_size[i];
2464 btrfs_set_item_size(leaf, item, data_size[i]);
2465 }
2466 btrfs_set_header_nritems(leaf, nritems + nr);
2467 btrfs_mark_buffer_dirty(leaf);
2468
2469 ret = 0;
2470 if (slot == 0) {
2471 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2472 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2473 }
2474
2475 if (btrfs_leaf_free_space(root, leaf) < 0) {
2476 btrfs_print_leaf(root, leaf);
2477 BUG();
2478 }
2479
2480 out:
2481 return ret;
2482 }
2483
2484 /*
2485 * Given a key and some data, insert an item into the tree.
2486 * This does all the path init required, making room in the tree if needed.
2487 */
2488 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2489 *root, struct btrfs_key *cpu_key, void *data, u32
2490 data_size)
2491 {
2492 int ret = 0;
2493 struct btrfs_path *path;
2494 struct extent_buffer *leaf;
2495 unsigned long ptr;
2496
2497 path = btrfs_alloc_path();
2498 BUG_ON(!path);
2499 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2500 if (!ret) {
2501 leaf = path->nodes[0];
2502 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2503 write_extent_buffer(leaf, data, ptr, data_size);
2504 btrfs_mark_buffer_dirty(leaf);
2505 }
2506 btrfs_free_path(path);
2507 return ret;
2508 }
2509
2510 /*
2511 * delete the pointer from a given node.
2512 *
2513 * If the delete empties a node, the node is removed from the tree,
2514 * continuing all the way the root if required. The root is converted into
2515 * a leaf if all the nodes are emptied.
2516 */
2517 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2518 struct btrfs_path *path, int level, int slot)
2519 {
2520 struct extent_buffer *parent = path->nodes[level];
2521 u32 nritems;
2522 int ret = 0;
2523 int wret;
2524
2525 nritems = btrfs_header_nritems(parent);
2526 if (slot != nritems -1) {
2527 memmove_extent_buffer(parent,
2528 btrfs_node_key_ptr_offset(slot),
2529 btrfs_node_key_ptr_offset(slot + 1),
2530 sizeof(struct btrfs_key_ptr) *
2531 (nritems - slot - 1));
2532 }
2533 nritems--;
2534 btrfs_set_header_nritems(parent, nritems);
2535 if (nritems == 0 && parent == root->node) {
2536 BUG_ON(btrfs_header_level(root->node) != 1);
2537 /* just turn the root into a leaf and break */
2538 btrfs_set_header_level(root->node, 0);
2539 } else if (slot == 0) {
2540 struct btrfs_disk_key disk_key;
2541
2542 btrfs_node_key(parent, &disk_key, 0);
2543 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2544 if (wret)
2545 ret = wret;
2546 }
2547 btrfs_mark_buffer_dirty(parent);
2548 return ret;
2549 }
2550
2551 /*
2552 * delete the item at the leaf level in path. If that empties
2553 * the leaf, remove it from the tree
2554 */
2555 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2556 struct btrfs_path *path, int slot, int nr)
2557 {
2558 struct extent_buffer *leaf;
2559 struct btrfs_item *item;
2560 int last_off;
2561 int dsize = 0;
2562 int ret = 0;
2563 int wret;
2564 int i;
2565 u32 nritems;
2566
2567 leaf = path->nodes[0];
2568 last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
2569
2570 for (i = 0; i < nr; i++)
2571 dsize += btrfs_item_size_nr(leaf, slot + i);
2572
2573 nritems = btrfs_header_nritems(leaf);
2574
2575 if (slot + nr != nritems) {
2576 int i;
2577 int data_end = leaf_data_end(root, leaf);
2578
2579 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2580 data_end + dsize,
2581 btrfs_leaf_data(leaf) + data_end,
2582 last_off - data_end);
2583
2584 for (i = slot + nr; i < nritems; i++) {
2585 u32 ioff;
2586
2587 item = btrfs_item_nr(leaf, i);
2588 if (!leaf->map_token) {
2589 map_extent_buffer(leaf, (unsigned long)item,
2590 sizeof(struct btrfs_item),
2591 &leaf->map_token, &leaf->kaddr,
2592 &leaf->map_start, &leaf->map_len,
2593 KM_USER1);
2594 }
2595 ioff = btrfs_item_offset(leaf, item);
2596 btrfs_set_item_offset(leaf, item, ioff + dsize);
2597 }
2598
2599 if (leaf->map_token) {
2600 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2601 leaf->map_token = NULL;
2602 }
2603
2604 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2605 btrfs_item_nr_offset(slot + nr),
2606 sizeof(struct btrfs_item) *
2607 (nritems - slot - nr));
2608 }
2609 btrfs_set_header_nritems(leaf, nritems - nr);
2610 nritems -= nr;
2611
2612 /* delete the leaf if we've emptied it */
2613 if (nritems == 0) {
2614 if (leaf == root->node) {
2615 btrfs_set_header_level(leaf, 0);
2616 } else {
2617 u64 root_gen = btrfs_header_generation(path->nodes[1]);
2618 clean_tree_block(trans, root, leaf);
2619 wait_on_tree_block_writeback(root, leaf);
2620 wret = del_ptr(trans, root, path, 1, path->slots[1]);
2621 if (wret)
2622 ret = wret;
2623 wret = btrfs_free_extent(trans, root,
2624 leaf->start, leaf->len,
2625 btrfs_header_owner(path->nodes[1]),
2626 root_gen, 0, 0, 1);
2627 if (wret)
2628 ret = wret;
2629 }
2630 } else {
2631 int used = leaf_space_used(leaf, 0, nritems);
2632 if (slot == 0) {
2633 struct btrfs_disk_key disk_key;
2634
2635 btrfs_item_key(leaf, &disk_key, 0);
2636 wret = fixup_low_keys(trans, root, path,
2637 &disk_key, 1);
2638 if (wret)
2639 ret = wret;
2640 }
2641
2642 /* delete the leaf if it is mostly empty */
2643 if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
2644 /* push_leaf_left fixes the path.
2645 * make sure the path still points to our leaf
2646 * for possible call to del_ptr below
2647 */
2648 slot = path->slots[1];
2649 extent_buffer_get(leaf);
2650
2651 wret = push_leaf_left(trans, root, path, 1, 1);
2652 if (wret < 0 && wret != -ENOSPC)
2653 ret = wret;
2654
2655 if (path->nodes[0] == leaf &&
2656 btrfs_header_nritems(leaf)) {
2657 wret = push_leaf_right(trans, root, path, 1, 1);
2658 if (wret < 0 && wret != -ENOSPC)
2659 ret = wret;
2660 }
2661
2662 if (btrfs_header_nritems(leaf) == 0) {
2663 u64 root_gen;
2664 u64 bytenr = leaf->start;
2665 u32 blocksize = leaf->len;
2666
2667 root_gen = btrfs_header_generation(
2668 path->nodes[1]);
2669
2670 clean_tree_block(trans, root, leaf);
2671 wait_on_tree_block_writeback(root, leaf);
2672
2673 wret = del_ptr(trans, root, path, 1, slot);
2674 if (wret)
2675 ret = wret;
2676
2677 free_extent_buffer(leaf);
2678 wret = btrfs_free_extent(trans, root, bytenr,
2679 blocksize,
2680 btrfs_header_owner(path->nodes[1]),
2681 root_gen, 0, 0, 1);
2682 if (wret)
2683 ret = wret;
2684 } else {
2685 btrfs_mark_buffer_dirty(leaf);
2686 free_extent_buffer(leaf);
2687 }
2688 } else {
2689 btrfs_mark_buffer_dirty(leaf);
2690 }
2691 }
2692 return ret;
2693 }
2694
2695 /*
2696 * walk up the tree as far as required to find the previous leaf.
2697 * returns 0 if it found something or 1 if there are no lesser leaves.
2698 * returns < 0 on io errors.
2699 */
2700 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
2701 {
2702 u64 bytenr;
2703 int slot;
2704 int level = 1;
2705 struct extent_buffer *c;
2706 struct extent_buffer *next = NULL;
2707
2708 while(level < BTRFS_MAX_LEVEL) {
2709 if (!path->nodes[level])
2710 return 1;
2711
2712 slot = path->slots[level];
2713 c = path->nodes[level];
2714 if (slot == 0) {
2715 level++;
2716 if (level == BTRFS_MAX_LEVEL)
2717 return 1;
2718 continue;
2719 }
2720 slot--;
2721
2722 bytenr = btrfs_node_blockptr(c, slot);
2723 if (next)
2724 free_extent_buffer(next);
2725
2726 next = read_tree_block(root, bytenr,
2727 btrfs_level_size(root, level - 1));
2728 break;
2729 }
2730 path->slots[level] = slot;
2731 while(1) {
2732 level--;
2733 c = path->nodes[level];
2734 free_extent_buffer(c);
2735 slot = btrfs_header_nritems(next);
2736 if (slot != 0)
2737 slot--;
2738 path->nodes[level] = next;
2739 path->slots[level] = slot;
2740 if (!level)
2741 break;
2742 next = read_tree_block(root, btrfs_node_blockptr(next, slot),
2743 btrfs_level_size(root, level - 1));
2744 }
2745 return 0;
2746 }
2747
2748 /*
2749 * walk up the tree as far as required to find the next leaf.
2750 * returns 0 if it found something or 1 if there are no greater leaves.
2751 * returns < 0 on io errors.
2752 */
2753 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2754 {
2755 int slot;
2756 int level = 1;
2757 u64 bytenr;
2758 struct extent_buffer *c;
2759 struct extent_buffer *next = NULL;
2760
2761 while(level < BTRFS_MAX_LEVEL) {
2762 if (!path->nodes[level])
2763 return 1;
2764
2765 slot = path->slots[level] + 1;
2766 c = path->nodes[level];
2767 if (slot >= btrfs_header_nritems(c)) {
2768 level++;
2769 if (level == BTRFS_MAX_LEVEL)
2770 return 1;
2771 continue;
2772 }
2773
2774 bytenr = btrfs_node_blockptr(c, slot);
2775 if (next)
2776 free_extent_buffer(next);
2777
2778 if (path->reada)
2779 reada_for_search(root, path, level, slot, 0);
2780
2781 next = read_tree_block(root, bytenr,
2782 btrfs_level_size(root, level -1));
2783 break;
2784 }
2785 path->slots[level] = slot;
2786 while(1) {
2787 level--;
2788 c = path->nodes[level];
2789 free_extent_buffer(c);
2790 path->nodes[level] = next;
2791 path->slots[level] = 0;
2792 if (!level)
2793 break;
2794 if (path->reada)
2795 reada_for_search(root, path, level, 0, 0);
2796 next = read_tree_block(root, btrfs_node_blockptr(next, 0),
2797 btrfs_level_size(root, level - 1));
2798 }
2799 return 0;
2800 }
2801
2802 int btrfs_previous_item(struct btrfs_root *root,
2803 struct btrfs_path *path, u64 min_objectid,
2804 int type)
2805 {
2806 struct btrfs_key found_key;
2807 struct extent_buffer *leaf;
2808 int ret;
2809
2810 while(1) {
2811 if (path->slots[0] == 0) {
2812 ret = btrfs_prev_leaf(root, path);
2813 if (ret != 0)
2814 return ret;
2815 } else {
2816 path->slots[0]--;
2817 }
2818 leaf = path->nodes[0];
2819 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2820 if (found_key.type == type)
2821 return 0;
2822 }
2823 return 1;
2824 }
2825
Linux kernel - Deliverables
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