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