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update btrfs-progs for seed device support
[btrfs-progs-unstable/devel.git] / ctree.c
blob0d9797e50b847bfa420d5142af0c512e3f62f534
1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18 #include "ctree.h"
19 #include "disk-io.h"
20 #include "transaction.h"
21 #include "print-tree.h"
22
23 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
24 *root, struct btrfs_path *path, int level);
25 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
26 *root, struct btrfs_key *ins_key,
27 struct btrfs_path *path, int data_size, int extend);
28 static int push_node_left(struct btrfs_trans_handle *trans,
29 struct btrfs_root *root, struct extent_buffer *dst,
30 struct extent_buffer *src, int empty);
31 static int balance_node_right(struct btrfs_trans_handle *trans,
32 struct btrfs_root *root,
33 struct extent_buffer *dst_buf,
34 struct extent_buffer *src_buf);
35 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
36 struct btrfs_path *path, int level, int slot);
37
38 inline void btrfs_init_path(struct btrfs_path *p)
39 {
40 memset(p, 0, sizeof(*p));
41 }
42
43 struct btrfs_path *btrfs_alloc_path(void)
44 {
45 struct btrfs_path *path;
46 path = kmalloc(sizeof(struct btrfs_path), GFP_NOFS);
47 if (path) {
48 btrfs_init_path(path);
49 path->reada = 0;
50 }
51 return path;
52 }
53
54 void btrfs_free_path(struct btrfs_path *p)
55 {
56 btrfs_release_path(NULL, p);
57 kfree(p);
58 }
59
60 void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
61 {
62 int i;
63 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
64 if (!p->nodes[i])
65 break;
66 free_extent_buffer(p->nodes[i]);
67 }
68 memset(p, 0, sizeof(*p));
69 }
70
71 static void add_root_to_dirty_list(struct btrfs_root *root)
72 {
73 if (root->track_dirty && list_empty(&root->dirty_list)) {
74 list_add(&root->dirty_list,
75 &root->fs_info->dirty_cowonly_roots);
76 }
77 }
78
79 int btrfs_copy_root(struct btrfs_trans_handle *trans,
80 struct btrfs_root *root,
81 struct extent_buffer *buf,
82 struct extent_buffer **cow_ret, u64 new_root_objectid)
83 {
84 struct extent_buffer *cow;
85 int ret = 0;
86 int level;
87 struct btrfs_root *new_root;
88
89 new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
90 if (!new_root)
91 return -ENOMEM;
92
93 memcpy(new_root, root, sizeof(*new_root));
94 new_root->root_key.objectid = new_root_objectid;
95
96 WARN_ON(root->ref_cows && trans->transid !=
97 root->fs_info->running_transaction->transid);
98 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
99
100 level = btrfs_header_level(buf);
101 cow = btrfs_alloc_free_block(trans, new_root, buf->len, 0,
102 new_root_objectid, trans->transid,
103 level, buf->start, 0);
104 if (IS_ERR(cow)) {
105 kfree(new_root);
106 return PTR_ERR(cow);
107 }
108
109 copy_extent_buffer(cow, buf, 0, 0, cow->len);
110 btrfs_set_header_bytenr(cow, cow->start);
111 btrfs_set_header_generation(cow, trans->transid);
112 btrfs_set_header_owner(cow, new_root_objectid);
113 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
114
115 write_extent_buffer(cow, root->fs_info->fsid,
116 (unsigned long)btrfs_header_fsid(cow),
117 BTRFS_FSID_SIZE);
118
119 WARN_ON(btrfs_header_generation(buf) > trans->transid);
120 ret = btrfs_inc_ref(trans, new_root, buf, cow, NULL);
121 kfree(new_root);
122
123 if (ret)
124 return ret;
125
126 btrfs_mark_buffer_dirty(cow);
127 *cow_ret = cow;
128 return 0;
129 }
130
131 int __btrfs_cow_block(struct btrfs_trans_handle *trans,
132 struct btrfs_root *root,
133 struct extent_buffer *buf,
134 struct extent_buffer *parent, int parent_slot,
135 struct extent_buffer **cow_ret,
136 u64 search_start, u64 empty_size)
137 {
138 u64 parent_start;
139 struct extent_buffer *cow;
140 u32 nritems;
141 int ret = 0;
142 int different_trans = 0;
143 int level;
144
145 WARN_ON(root->ref_cows && trans->transid !=
146 root->fs_info->running_transaction->transid);
147 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
148
149 if (parent)
150 parent_start = parent->start;
151 else
152 parent_start = 0;
153
154 level = btrfs_header_level(buf);
155 nritems = btrfs_header_nritems(buf);
156 cow = btrfs_alloc_free_block(trans, root, buf->len, parent_start,
157 root->root_key.objectid, trans->transid,
158 level, search_start, empty_size);
159 if (IS_ERR(cow))
160 return PTR_ERR(cow);
161
162 copy_extent_buffer(cow, buf, 0, 0, cow->len);
163 btrfs_set_header_bytenr(cow, cow->start);
164 btrfs_set_header_generation(cow, trans->transid);
165 btrfs_set_header_owner(cow, root->root_key.objectid);
166 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
167
168 write_extent_buffer(cow, root->fs_info->fsid,
169 (unsigned long)btrfs_header_fsid(cow),
170 BTRFS_FSID_SIZE);
171
172 WARN_ON(btrfs_header_generation(buf) > trans->transid);
173 if (btrfs_header_generation(buf) != trans->transid) {
174 different_trans = 1;
175 ret = btrfs_inc_ref(trans, root, buf, cow, NULL);
176 if (ret)
177 return ret;
178 } else {
179 ret = btrfs_update_ref(trans, root, buf, cow, 0, nritems);
180 if (ret)
181 return ret;
182 clean_tree_block(trans, root, buf);
183 }
184
185 if (buf == root->node) {
186 root->node = cow;
187 extent_buffer_get(cow);
188 if (buf != root->commit_root) {
189 btrfs_free_extent(trans, root, buf->start,
190 buf->len, buf->start,
191 root->root_key.objectid,
192 btrfs_header_generation(buf),
193 level, 1);
194 }
195 free_extent_buffer(buf);
196 add_root_to_dirty_list(root);
197 } else {
198 btrfs_set_node_blockptr(parent, parent_slot,
199 cow->start);
200 WARN_ON(trans->transid == 0);
201 btrfs_set_node_ptr_generation(parent, parent_slot,
202 trans->transid);
203 btrfs_mark_buffer_dirty(parent);
204 WARN_ON(btrfs_header_generation(parent) != trans->transid);
205 btrfs_free_extent(trans, root, buf->start, buf->len,
206 parent_start, btrfs_header_owner(parent),
207 btrfs_header_generation(parent), level, 1);
208 }
209 free_extent_buffer(buf);
210 btrfs_mark_buffer_dirty(cow);
211 *cow_ret = cow;
212 return 0;
213 }
214
215 int btrfs_cow_block(struct btrfs_trans_handle *trans,
216 struct btrfs_root *root, struct extent_buffer *buf,
217 struct extent_buffer *parent, int parent_slot,
218 struct extent_buffer **cow_ret)
219 {
220 u64 search_start;
221 int ret;
222 /*
223 if (trans->transaction != root->fs_info->running_transaction) {
224 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
225 root->fs_info->running_transaction->transid);
226 WARN_ON(1);
227 }
228 */
229 if (trans->transid != root->fs_info->generation) {
230 printk(KERN_CRIT "trans %llu running %llu\n",
231 (unsigned long long)trans->transid,
232 (unsigned long long)root->fs_info->generation);
233 WARN_ON(1);
234 }
235 if (btrfs_header_generation(buf) == trans->transid &&
236 !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
237 *cow_ret = buf;
238 return 0;
239 }
240
241 search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
242 ret = __btrfs_cow_block(trans, root, buf, parent,
243 parent_slot, cow_ret, search_start, 0);
244 return ret;
245 }
246
247 /*
248 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
249 {
250 if (blocknr < other && other - (blocknr + blocksize) < 32768)
251 return 1;
252 if (blocknr > other && blocknr - (other + blocksize) < 32768)
253 return 1;
254 return 0;
255 }
256 */
257
258 /*
259 * compare two keys in a memcmp fashion
260 */
261 int btrfs_comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
262 {
263 struct btrfs_key k1;
264
265 btrfs_disk_key_to_cpu(&k1, disk);
266
267 if (k1.objectid > k2->objectid)
268 return 1;
269 if (k1.objectid < k2->objectid)
270 return -1;
271 if (k1.type > k2->type)
272 return 1;
273 if (k1.type < k2->type)
274 return -1;
275 if (k1.offset > k2->offset)
276 return 1;
277 if (k1.offset < k2->offset)
278 return -1;
279 return 0;
280 }
281
282
283 #if 0
284 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
285 struct btrfs_root *root, struct extent_buffer *parent,
286 int start_slot, int cache_only, u64 *last_ret,
287 struct btrfs_key *progress)
288 {
289 struct extent_buffer *cur;
290 struct extent_buffer *tmp;
291 u64 blocknr;
292 u64 gen;
293 u64 search_start = *last_ret;
294 u64 last_block = 0;
295 u64 other;
296 u32 parent_nritems;
297 int end_slot;
298 int i;
299 int err = 0;
300 int parent_level;
301 int uptodate;
302 u32 blocksize;
303 int progress_passed = 0;
304 struct btrfs_disk_key disk_key;
305
306 parent_level = btrfs_header_level(parent);
307 if (cache_only && parent_level != 1)
308 return 0;
309
310 if (trans->transaction != root->fs_info->running_transaction) {
311 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
312 root->fs_info->running_transaction->transid);
313 WARN_ON(1);
314 }
315 if (trans->transid != root->fs_info->generation) {
316 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
317 root->fs_info->generation);
318 WARN_ON(1);
319 }
320
321 parent_nritems = btrfs_header_nritems(parent);
322 blocksize = btrfs_level_size(root, parent_level - 1);
323 end_slot = parent_nritems;
324
325 if (parent_nritems == 1)
326 return 0;
327
328 for (i = start_slot; i < end_slot; i++) {
329 int close = 1;
330
331 if (!parent->map_token) {
332 map_extent_buffer(parent,
333 btrfs_node_key_ptr_offset(i),
334 sizeof(struct btrfs_key_ptr),
335 &parent->map_token, &parent->kaddr,
336 &parent->map_start, &parent->map_len,
337 KM_USER1);
338 }
339 btrfs_node_key(parent, &disk_key, i);
340 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
341 continue;
342
343 progress_passed = 1;
344 blocknr = btrfs_node_blockptr(parent, i);
345 gen = btrfs_node_ptr_generation(parent, i);
346 if (last_block == 0)
347 last_block = blocknr;
348
349 if (i > 0) {
350 other = btrfs_node_blockptr(parent, i - 1);
351 close = close_blocks(blocknr, other, blocksize);
352 }
353 if (close && i < end_slot - 2) {
354 other = btrfs_node_blockptr(parent, i + 1);
355 close = close_blocks(blocknr, other, blocksize);
356 }
357 if (close) {
358 last_block = blocknr;
359 continue;
360 }
361 if (parent->map_token) {
362 unmap_extent_buffer(parent, parent->map_token,
363 KM_USER1);
364 parent->map_token = NULL;
365 }
366
367 cur = btrfs_find_tree_block(root, blocknr, blocksize);
368 if (cur)
369 uptodate = btrfs_buffer_uptodate(cur, gen);
370 else
371 uptodate = 0;
372 if (!cur || !uptodate) {
373 if (cache_only) {
374 free_extent_buffer(cur);
375 continue;
376 }
377 if (!cur) {
378 cur = read_tree_block(root, blocknr,
379 blocksize, gen);
380 } else if (!uptodate) {
381 btrfs_read_buffer(cur, gen);
382 }
383 }
384 if (search_start == 0)
385 search_start = last_block;
386
387 err = __btrfs_cow_block(trans, root, cur, parent, i,
388 &tmp, search_start,
389 min(16 * blocksize,
390 (end_slot - i) * blocksize));
391 if (err) {
392 free_extent_buffer(cur);
393 break;
394 }
395 search_start = tmp->start;
396 last_block = tmp->start;
397 *last_ret = search_start;
398 if (parent_level == 1)
399 btrfs_clear_buffer_defrag(tmp);
400 free_extent_buffer(tmp);
401 }
402 if (parent->map_token) {
403 unmap_extent_buffer(parent, parent->map_token,
404 KM_USER1);
405 parent->map_token = NULL;
406 }
407 return err;
408 }
409 #endif
410
411 /*
412 * The leaf data grows from end-to-front in the node.
413 * this returns the address of the start of the last item,
414 * which is the stop of the leaf data stack
415 */
416 static inline unsigned int leaf_data_end(struct btrfs_root *root,
417 struct extent_buffer *leaf)
418 {
419 u32 nr = btrfs_header_nritems(leaf);
420 if (nr == 0)
421 return BTRFS_LEAF_DATA_SIZE(root);
422 return btrfs_item_offset_nr(leaf, nr - 1);
423 }
424
425 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
426 int level)
427 {
428 struct extent_buffer *parent = NULL;
429 struct extent_buffer *node = path->nodes[level];
430 struct btrfs_disk_key parent_key;
431 struct btrfs_disk_key node_key;
432 int parent_slot;
433 int slot;
434 struct btrfs_key cpukey;
435 u32 nritems = btrfs_header_nritems(node);
436
437 if (path->nodes[level + 1])
438 parent = path->nodes[level + 1];
439
440 slot = path->slots[level];
441 BUG_ON(nritems == 0);
442 if (parent) {
443 parent_slot = path->slots[level + 1];
444 btrfs_node_key(parent, &parent_key, parent_slot);
445 btrfs_node_key(node, &node_key, 0);
446 BUG_ON(memcmp(&parent_key, &node_key,
447 sizeof(struct btrfs_disk_key)));
448 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
449 btrfs_header_bytenr(node));
450 }
451 BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
452 if (slot != 0) {
453 btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
454 btrfs_node_key(node, &node_key, slot);
455 BUG_ON(btrfs_comp_keys(&node_key, &cpukey) <= 0);
456 }
457 if (slot < nritems - 1) {
458 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
459 btrfs_node_key(node, &node_key, slot);
460 BUG_ON(btrfs_comp_keys(&node_key, &cpukey) >= 0);
461 }
462 return 0;
463 }
464
465 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
466 int level)
467 {
468 struct extent_buffer *leaf = path->nodes[level];
469 struct extent_buffer *parent = NULL;
470 int parent_slot;
471 struct btrfs_key cpukey;
472 struct btrfs_disk_key parent_key;
473 struct btrfs_disk_key leaf_key;
474 int slot = path->slots[0];
475
476 u32 nritems = btrfs_header_nritems(leaf);
477
478 if (path->nodes[level + 1])
479 parent = path->nodes[level + 1];
480
481 if (nritems == 0)
482 return 0;
483
484 if (parent) {
485 parent_slot = path->slots[level + 1];
486 btrfs_node_key(parent, &parent_key, parent_slot);
487 btrfs_item_key(leaf, &leaf_key, 0);
488
489 BUG_ON(memcmp(&parent_key, &leaf_key,
490 sizeof(struct btrfs_disk_key)));
491 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
492 btrfs_header_bytenr(leaf));
493 }
494 #if 0
495 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
496 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
497 btrfs_item_key(leaf, &leaf_key, i);
498 if (comp_keys(&leaf_key, &cpukey) >= 0) {
499 btrfs_print_leaf(root, leaf);
500 printk("slot %d offset bad key\n", i);
501 BUG_ON(1);
502 }
503 if (btrfs_item_offset_nr(leaf, i) !=
504 btrfs_item_end_nr(leaf, i + 1)) {
505 btrfs_print_leaf(root, leaf);
506 printk("slot %d offset bad\n", i);
507 BUG_ON(1);
508 }
509 if (i == 0) {
510 if (btrfs_item_offset_nr(leaf, i) +
511 btrfs_item_size_nr(leaf, i) !=
512 BTRFS_LEAF_DATA_SIZE(root)) {
513 btrfs_print_leaf(root, leaf);
514 printk("slot %d first offset bad\n", i);
515 BUG_ON(1);
516 }
517 }
518 }
519 if (nritems > 0) {
520 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
521 btrfs_print_leaf(root, leaf);
522 printk("slot %d bad size \n", nritems - 1);
523 BUG_ON(1);
524 }
525 }
526 #endif
527 if (slot != 0 && slot < nritems - 1) {
528 btrfs_item_key(leaf, &leaf_key, slot);
529 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
530 if (btrfs_comp_keys(&leaf_key, &cpukey) <= 0) {
531 btrfs_print_leaf(root, leaf);
532 printk("slot %d offset bad key\n", slot);
533 BUG_ON(1);
534 }
535 if (btrfs_item_offset_nr(leaf, slot - 1) !=
536 btrfs_item_end_nr(leaf, slot)) {
537 btrfs_print_leaf(root, leaf);
538 printk("slot %d offset bad\n", slot);
539 BUG_ON(1);
540 }
541 }
542 if (slot < nritems - 1) {
543 btrfs_item_key(leaf, &leaf_key, slot);
544 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
545 BUG_ON(btrfs_comp_keys(&leaf_key, &cpukey) >= 0);
546 if (btrfs_item_offset_nr(leaf, slot) !=
547 btrfs_item_end_nr(leaf, slot + 1)) {
548 btrfs_print_leaf(root, leaf);
549 printk("slot %d offset bad\n", slot);
550 BUG_ON(1);
551 }
552 }
553 BUG_ON(btrfs_item_offset_nr(leaf, 0) +
554 btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
555 return 0;
556 }
557
558 static int noinline check_block(struct btrfs_root *root,
559 struct btrfs_path *path, int level)
560 {
561 return 0;
562 #if 0
563 struct extent_buffer *buf = path->nodes[level];
564
565 if (memcmp_extent_buffer(buf, root->fs_info->fsid,
566 (unsigned long)btrfs_header_fsid(buf),
567 BTRFS_FSID_SIZE)) {
568 printk("warning bad block %Lu\n", buf->start);
569 return 1;
570 }
571 #endif
572 if (level == 0)
573 return check_leaf(root, path, level);
574 return check_node(root, path, level);
575 }
576
577 /*
578 * search for key in the extent_buffer. The items start at offset p,
579 * and they are item_size apart. There are 'max' items in p.
580 *
581 * the slot in the array is returned via slot, and it points to
582 * the place where you would insert key if it is not found in
583 * the array.
584 *
585 * slot may point to max if the key is bigger than all of the keys
586 */
587 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
588 int item_size, struct btrfs_key *key,
589 int max, int *slot)
590 {
591 int low = 0;
592 int high = max;
593 int mid;
594 int ret;
595 unsigned long offset;
596 struct btrfs_disk_key *tmp;
597
598 while(low < high) {
599 mid = (low + high) / 2;
600 offset = p + mid * item_size;
601
602 tmp = (struct btrfs_disk_key *)(eb->data + offset);
603 ret = btrfs_comp_keys(tmp, key);
604
605 if (ret < 0)
606 low = mid + 1;
607 else if (ret > 0)
608 high = mid;
609 else {
610 *slot = mid;
611 return 0;
612 }
613 }
614 *slot = low;
615 return 1;
616 }
617
618 /*
619 * simple bin_search frontend that does the right thing for
620 * leaves vs nodes
621 */
622 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
623 int level, int *slot)
624 {
625 if (level == 0) {
626 return generic_bin_search(eb,
627 offsetof(struct btrfs_leaf, items),
628 sizeof(struct btrfs_item),
629 key, btrfs_header_nritems(eb),
630 slot);
631 } else {
632 return generic_bin_search(eb,
633 offsetof(struct btrfs_node, ptrs),
634 sizeof(struct btrfs_key_ptr),
635 key, btrfs_header_nritems(eb),
636 slot);
637 }
638 return -1;
639 }
640
641 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
642 struct extent_buffer *parent, int slot)
643 {
644 int level = btrfs_header_level(parent);
645 if (slot < 0)
646 return NULL;
647 if (slot >= btrfs_header_nritems(parent))
648 return NULL;
649
650 BUG_ON(level == 0);
651
652 return read_tree_block(root, btrfs_node_blockptr(parent, slot),
653 btrfs_level_size(root, level - 1),
654 btrfs_node_ptr_generation(parent, slot));
655 }
656
657 static int balance_level(struct btrfs_trans_handle *trans,
658 struct btrfs_root *root,
659 struct btrfs_path *path, int level)
660 {
661 struct extent_buffer *right = NULL;
662 struct extent_buffer *mid;
663 struct extent_buffer *left = NULL;
664 struct extent_buffer *parent = NULL;
665 int ret = 0;
666 int wret;
667 int pslot;
668 int orig_slot = path->slots[level];
669 int err_on_enospc = 0;
670 u64 orig_ptr;
671
672 if (level == 0)
673 return 0;
674
675 mid = path->nodes[level];
676 WARN_ON(btrfs_header_generation(mid) != trans->transid);
677
678 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
679
680 if (level < BTRFS_MAX_LEVEL - 1)
681 parent = path->nodes[level + 1];
682 pslot = path->slots[level + 1];
683
684 /*
685 * deal with the case where there is only one pointer in the root
686 * by promoting the node below to a root
687 */
688 if (!parent) {
689 struct extent_buffer *child;
690
691 if (btrfs_header_nritems(mid) != 1)
692 return 0;
693
694 /* promote the child to a root */
695 child = read_node_slot(root, mid, 0);
696 BUG_ON(!child);
697 ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
698 BUG_ON(ret);
699
700 root->node = child;
701
702 ret = btrfs_update_extent_ref(trans, root, child->start,
703 mid->start, child->start,
704 root->root_key.objectid,
705 trans->transid, level - 1);
706 BUG_ON(ret);
707
708 add_root_to_dirty_list(root);
709 path->nodes[level] = NULL;
710 clean_tree_block(trans, root, mid);
711 wait_on_tree_block_writeback(root, mid);
712 /* once for the path */
713 free_extent_buffer(mid);
714 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
715 mid->start, root->root_key.objectid,
716 btrfs_header_generation(mid),
717 level, 1);
718 /* once for the root ptr */
719 free_extent_buffer(mid);
720 return ret;
721 }
722 if (btrfs_header_nritems(mid) >
723 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
724 return 0;
725
726 if (btrfs_header_nritems(mid) < 2)
727 err_on_enospc = 1;
728
729 left = read_node_slot(root, parent, pslot - 1);
730 if (left) {
731 wret = btrfs_cow_block(trans, root, left,
732 parent, pslot - 1, &left);
733 if (wret) {
734 ret = wret;
735 goto enospc;
736 }
737 }
738 right = read_node_slot(root, parent, pslot + 1);
739 if (right) {
740 wret = btrfs_cow_block(trans, root, right,
741 parent, pslot + 1, &right);
742 if (wret) {
743 ret = wret;
744 goto enospc;
745 }
746 }
747
748 /* first, try to make some room in the middle buffer */
749 if (left) {
750 orig_slot += btrfs_header_nritems(left);
751 wret = push_node_left(trans, root, left, mid, 1);
752 if (wret < 0)
753 ret = wret;
754 if (btrfs_header_nritems(mid) < 2)
755 err_on_enospc = 1;
756 }
757
758 /*
759 * then try to empty the right most buffer into the middle
760 */
761 if (right) {
762 wret = push_node_left(trans, root, mid, right, 1);
763 if (wret < 0 && wret != -ENOSPC)
764 ret = wret;
765 if (btrfs_header_nritems(right) == 0) {
766 u64 bytenr = right->start;
767 u64 generation = btrfs_header_generation(parent);
768 u32 blocksize = right->len;
769
770 clean_tree_block(trans, root, right);
771 wait_on_tree_block_writeback(root, right);
772 free_extent_buffer(right);
773 right = NULL;
774 wret = del_ptr(trans, root, path, level + 1, pslot +
775 1);
776 if (wret)
777 ret = wret;
778 wret = btrfs_free_extent(trans, root, bytenr,
779 blocksize, parent->start,
780 btrfs_header_owner(parent),
781 generation, level, 1);
782 if (wret)
783 ret = wret;
784 } else {
785 struct btrfs_disk_key right_key;
786 btrfs_node_key(right, &right_key, 0);
787 btrfs_set_node_key(parent, &right_key, pslot + 1);
788 btrfs_mark_buffer_dirty(parent);
789 }
790 }
791 if (btrfs_header_nritems(mid) == 1) {
792 /*
793 * we're not allowed to leave a node with one item in the
794 * tree during a delete. A deletion from lower in the tree
795 * could try to delete the only pointer in this node.
796 * So, pull some keys from the left.
797 * There has to be a left pointer at this point because
798 * otherwise we would have pulled some pointers from the
799 * right
800 */
801 BUG_ON(!left);
802 wret = balance_node_right(trans, root, mid, left);
803 if (wret < 0) {
804 ret = wret;
805 goto enospc;
806 }
807 if (wret == 1) {
808 wret = push_node_left(trans, root, left, mid, 1);
809 if (wret < 0)
810 ret = wret;
811 }
812 BUG_ON(wret == 1);
813 }
814 if (btrfs_header_nritems(mid) == 0) {
815 /* we've managed to empty the middle node, drop it */
816 u64 root_gen = btrfs_header_generation(parent);
817 u64 bytenr = mid->start;
818 u32 blocksize = mid->len;
819 clean_tree_block(trans, root, mid);
820 wait_on_tree_block_writeback(root, mid);
821 free_extent_buffer(mid);
822 mid = NULL;
823 wret = del_ptr(trans, root, path, level + 1, pslot);
824 if (wret)
825 ret = wret;
826 wret = btrfs_free_extent(trans, root, bytenr, blocksize,
827 parent->start,
828 btrfs_header_owner(parent),
829 root_gen, level, 1);
830 if (wret)
831 ret = wret;
832 } else {
833 /* update the parent key to reflect our changes */
834 struct btrfs_disk_key mid_key;
835 btrfs_node_key(mid, &mid_key, 0);
836 btrfs_set_node_key(parent, &mid_key, pslot);
837 btrfs_mark_buffer_dirty(parent);
838 }
839
840 /* update the path */
841 if (left) {
842 if (btrfs_header_nritems(left) > orig_slot) {
843 extent_buffer_get(left);
844 path->nodes[level] = left;
845 path->slots[level + 1] -= 1;
846 path->slots[level] = orig_slot;
847 if (mid)
848 free_extent_buffer(mid);
849 } else {
850 orig_slot -= btrfs_header_nritems(left);
851 path->slots[level] = orig_slot;
852 }
853 }
854 /* double check we haven't messed things up */
855 check_block(root, path, level);
856 if (orig_ptr !=
857 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
858 BUG();
859 enospc:
860 if (right)
861 free_extent_buffer(right);
862 if (left)
863 free_extent_buffer(left);
864 return ret;
865 }
866
867 /* returns zero if the push worked, non-zero otherwise */
868 static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
869 struct btrfs_root *root,
870 struct btrfs_path *path, int level)
871 {
872 struct extent_buffer *right = NULL;
873 struct extent_buffer *mid;
874 struct extent_buffer *left = NULL;
875 struct extent_buffer *parent = NULL;
876 int ret = 0;
877 int wret;
878 int pslot;
879 int orig_slot = path->slots[level];
880 u64 orig_ptr;
881
882 if (level == 0)
883 return 1;
884
885 mid = path->nodes[level];
886 WARN_ON(btrfs_header_generation(mid) != trans->transid);
887 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
888
889 if (level < BTRFS_MAX_LEVEL - 1)
890 parent = path->nodes[level + 1];
891 pslot = path->slots[level + 1];
892
893 if (!parent)
894 return 1;
895
896 left = read_node_slot(root, parent, pslot - 1);
897
898 /* first, try to make some room in the middle buffer */
899 if (left) {
900 u32 left_nr;
901 left_nr = btrfs_header_nritems(left);
902 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
903 wret = 1;
904 } else {
905 ret = btrfs_cow_block(trans, root, left, parent,
906 pslot - 1, &left);
907 if (ret)
908 wret = 1;
909 else {
910 wret = push_node_left(trans, root,
911 left, mid, 0);
912 }
913 }
914 if (wret < 0)
915 ret = wret;
916 if (wret == 0) {
917 struct btrfs_disk_key disk_key;
918 orig_slot += left_nr;
919 btrfs_node_key(mid, &disk_key, 0);
920 btrfs_set_node_key(parent, &disk_key, pslot);
921 btrfs_mark_buffer_dirty(parent);
922 if (btrfs_header_nritems(left) > orig_slot) {
923 path->nodes[level] = left;
924 path->slots[level + 1] -= 1;
925 path->slots[level] = orig_slot;
926 free_extent_buffer(mid);
927 } else {
928 orig_slot -=
929 btrfs_header_nritems(left);
930 path->slots[level] = orig_slot;
931 free_extent_buffer(left);
932 }
933 return 0;
934 }
935 free_extent_buffer(left);
936 }
937 right= read_node_slot(root, parent, pslot + 1);
938
939 /*
940 * then try to empty the right most buffer into the middle
941 */
942 if (right) {
943 u32 right_nr;
944 right_nr = btrfs_header_nritems(right);
945 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
946 wret = 1;
947 } else {
948 ret = btrfs_cow_block(trans, root, right,
949 parent, pslot + 1,
950 &right);
951 if (ret)
952 wret = 1;
953 else {
954 wret = balance_node_right(trans, root,
955 right, mid);
956 }
957 }
958 if (wret < 0)
959 ret = wret;
960 if (wret == 0) {
961 struct btrfs_disk_key disk_key;
962
963 btrfs_node_key(right, &disk_key, 0);
964 btrfs_set_node_key(parent, &disk_key, pslot + 1);
965 btrfs_mark_buffer_dirty(parent);
966
967 if (btrfs_header_nritems(mid) <= orig_slot) {
968 path->nodes[level] = right;
969 path->slots[level + 1] += 1;
970 path->slots[level] = orig_slot -
971 btrfs_header_nritems(mid);
972 free_extent_buffer(mid);
973 } else {
974 free_extent_buffer(right);
975 }
976 return 0;
977 }
978 free_extent_buffer(right);
979 }
980 return 1;
981 }
982
983 /*
984 * readahead one full node of leaves
985 */
986 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
987 int level, int slot, u64 objectid)
988 {
989 struct extent_buffer *node;
990 struct btrfs_disk_key disk_key;
991 u32 nritems;
992 u64 search;
993 u64 lowest_read;
994 u64 highest_read;
995 u64 nread = 0;
996 int direction = path->reada;
997 struct extent_buffer *eb;
998 u32 nr;
999 u32 blocksize;
1000 u32 nscan = 0;
1001
1002 if (level != 1)
1003 return;
1004
1005 if (!path->nodes[level])
1006 return;
1007
1008 node = path->nodes[level];
1009 search = btrfs_node_blockptr(node, slot);
1010 blocksize = btrfs_level_size(root, level - 1);
1011 eb = btrfs_find_tree_block(root, search, blocksize);
1012 if (eb) {
1013 free_extent_buffer(eb);
1014 return;
1015 }
1016
1017 highest_read = search;
1018 lowest_read = search;
1019
1020 nritems = btrfs_header_nritems(node);
1021 nr = slot;
1022 while(1) {
1023 if (direction < 0) {
1024 if (nr == 0)
1025 break;
1026 nr--;
1027 } else if (direction > 0) {
1028 nr++;
1029 if (nr >= nritems)
1030 break;
1031 }
1032 if (path->reada < 0 && objectid) {
1033 btrfs_node_key(node, &disk_key, nr);
1034 if (btrfs_disk_key_objectid(&disk_key) != objectid)
1035 break;
1036 }
1037 search = btrfs_node_blockptr(node, nr);
1038 if ((search >= lowest_read && search <= highest_read) ||
1039 (search < lowest_read && lowest_read - search <= 32768) ||
1040 (search > highest_read && search - highest_read <= 32768)) {
1041 readahead_tree_block(root, search, blocksize,
1042 btrfs_node_ptr_generation(node, nr));
1043 nread += blocksize;
1044 }
1045 nscan++;
1046 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
1047 break;
1048 if(nread > (1024 * 1024) || nscan > 128)
1049 break;
1050
1051 if (search < lowest_read)
1052 lowest_read = search;
1053 if (search > highest_read)
1054 highest_read = search;
1055 }
1056 }
1057
1058 /*
1059 * look for key in the tree. path is filled in with nodes along the way
1060 * if key is found, we return zero and you can find the item in the leaf
1061 * level of the path (level 0)
1062 *
1063 * If the key isn't found, the path points to the slot where it should
1064 * be inserted, and 1 is returned. If there are other errors during the
1065 * search a negative error number is returned.
1066 *
1067 * if ins_len > 0, nodes and leaves will be split as we walk down the
1068 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
1069 * possible)
1070 */
1071 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
1072 *root, struct btrfs_key *key, struct btrfs_path *p, int
1073 ins_len, int cow)
1074 {
1075 struct extent_buffer *b;
1076 int slot;
1077 int ret;
1078 int level;
1079 int should_reada = p->reada;
1080 u8 lowest_level = 0;
1081
1082 lowest_level = p->lowest_level;
1083 WARN_ON(lowest_level && ins_len);
1084 WARN_ON(p->nodes[0] != NULL);
1085 /*
1086 WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
1087 */
1088 again:
1089 b = root->node;
1090 extent_buffer_get(b);
1091 while (b) {
1092 level = btrfs_header_level(b);
1093 if (cow) {
1094 int wret;
1095 wret = btrfs_cow_block(trans, root, b,
1096 p->nodes[level + 1],
1097 p->slots[level + 1],
1098 &b);
1099 if (wret) {
1100 free_extent_buffer(b);
1101 return wret;
1102 }
1103 }
1104 BUG_ON(!cow && ins_len);
1105 if (level != btrfs_header_level(b))
1106 WARN_ON(1);
1107 level = btrfs_header_level(b);
1108 p->nodes[level] = b;
1109 ret = check_block(root, p, level);
1110 if (ret)
1111 return -1;
1112 ret = bin_search(b, key, level, &slot);
1113 if (level != 0) {
1114 if (ret && slot > 0)
1115 slot -= 1;
1116 p->slots[level] = slot;
1117 if (ins_len > 0 && btrfs_header_nritems(b) >=
1118 BTRFS_NODEPTRS_PER_BLOCK(root) - 3) {
1119 int sret = split_node(trans, root, p, level);
1120 BUG_ON(sret > 0);
1121 if (sret)
1122 return sret;
1123 b = p->nodes[level];
1124 slot = p->slots[level];
1125 } else if (ins_len < 0) {
1126 int sret = balance_level(trans, root, p,
1127 level);
1128 if (sret)
1129 return sret;
1130 b = p->nodes[level];
1131 if (!b) {
1132 btrfs_release_path(NULL, p);
1133 goto again;
1134 }
1135 slot = p->slots[level];
1136 BUG_ON(btrfs_header_nritems(b) == 1);
1137 }
1138 /* this is only true while dropping a snapshot */
1139 if (level == lowest_level)
1140 break;
1141
1142 if (should_reada)
1143 reada_for_search(root, p, level, slot,
1144 key->objectid);
1145
1146 b = read_node_slot(root, b, slot);
1147 } else {
1148 p->slots[level] = slot;
1149 if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1150 sizeof(struct btrfs_item) + ins_len) {
1151 int sret = split_leaf(trans, root, key,
1152 p, ins_len, ret == 0);
1153 BUG_ON(sret > 0);
1154 if (sret)
1155 return sret;
1156 }
1157 return ret;
1158 }
1159 }
1160 return 1;
1161 }
1162
1163 /*
1164 * adjust the pointers going up the tree, starting at level
1165 * making sure the right key of each node is points to 'key'.
1166 * This is used after shifting pointers to the left, so it stops
1167 * fixing up pointers when a given leaf/node is not in slot 0 of the
1168 * higher levels
1169 *
1170 * If this fails to write a tree block, it returns -1, but continues
1171 * fixing up the blocks in ram so the tree is consistent.
1172 */
1173 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1174 struct btrfs_root *root, struct btrfs_path *path,
1175 struct btrfs_disk_key *key, int level)
1176 {
1177 int i;
1178 int ret = 0;
1179 struct extent_buffer *t;
1180
1181 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1182 int tslot = path->slots[i];
1183 if (!path->nodes[i])
1184 break;
1185 t = path->nodes[i];
1186 btrfs_set_node_key(t, key, tslot);
1187 btrfs_mark_buffer_dirty(path->nodes[i]);
1188 if (tslot != 0)
1189 break;
1190 }
1191 return ret;
1192 }
1193
1194 /*
1195 * update item key.
1196 *
1197 * This function isn't completely safe. It's the caller's responsibility
1198 * that the new key won't break the order
1199 */
1200 int btrfs_set_item_key_safe(struct btrfs_trans_handle *trans,
1201 struct btrfs_root *root, struct btrfs_path *path,
1202 struct btrfs_key *new_key)
1203 {
1204 struct btrfs_disk_key disk_key;
1205 struct extent_buffer *eb;
1206 int slot;
1207
1208 eb = path->nodes[0];
1209 slot = path->slots[0];
1210 if (slot > 0) {
1211 btrfs_item_key(eb, &disk_key, slot - 1);
1212 if (btrfs_comp_keys(&disk_key, new_key) >= 0)
1213 return -1;
1214 }
1215 if (slot < btrfs_header_nritems(eb) - 1) {
1216 btrfs_item_key(eb, &disk_key, slot + 1);
1217 if (btrfs_comp_keys(&disk_key, new_key) <= 0)
1218 return -1;
1219 }
1220
1221 btrfs_cpu_key_to_disk(&disk_key, new_key);
1222 btrfs_set_item_key(eb, &disk_key, slot);
1223 btrfs_mark_buffer_dirty(eb);
1224 if (slot == 0)
1225 fixup_low_keys(trans, root, path, &disk_key, 1);
1226 return 0;
1227 }
1228
1229 /*
1230 * try to push data from one node into the next node left in the
1231 * tree.
1232 *
1233 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1234 * error, and > 0 if there was no room in the left hand block.
1235 */
1236 static int push_node_left(struct btrfs_trans_handle *trans,
1237 struct btrfs_root *root, struct extent_buffer *dst,
1238 struct extent_buffer *src, int empty)
1239 {
1240 int push_items = 0;
1241 int src_nritems;
1242 int dst_nritems;
1243 int ret = 0;
1244
1245 src_nritems = btrfs_header_nritems(src);
1246 dst_nritems = btrfs_header_nritems(dst);
1247 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1248 WARN_ON(btrfs_header_generation(src) != trans->transid);
1249 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1250
1251 if (!empty && src_nritems <= 8)
1252 return 1;
1253
1254 if (push_items <= 0) {
1255 return 1;
1256 }
1257
1258 if (empty) {
1259 push_items = min(src_nritems, push_items);
1260 if (push_items < src_nritems) {
1261 /* leave at least 8 pointers in the node if
1262 * we aren't going to empty it
1263 */
1264 if (src_nritems - push_items < 8) {
1265 if (push_items <= 8)
1266 return 1;
1267 push_items -= 8;
1268 }
1269 }
1270 } else
1271 push_items = min(src_nritems - 8, push_items);
1272
1273 copy_extent_buffer(dst, src,
1274 btrfs_node_key_ptr_offset(dst_nritems),
1275 btrfs_node_key_ptr_offset(0),
1276 push_items * sizeof(struct btrfs_key_ptr));
1277
1278 if (push_items < src_nritems) {
1279 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1280 btrfs_node_key_ptr_offset(push_items),
1281 (src_nritems - push_items) *
1282 sizeof(struct btrfs_key_ptr));
1283 }
1284 btrfs_set_header_nritems(src, src_nritems - push_items);
1285 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1286 btrfs_mark_buffer_dirty(src);
1287 btrfs_mark_buffer_dirty(dst);
1288
1289 ret = btrfs_update_ref(trans, root, src, dst, dst_nritems, push_items);
1290 BUG_ON(ret);
1291 return ret;
1292 }
1293
1294 /*
1295 * try to push data from one node into the next node right in the
1296 * tree.
1297 *
1298 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1299 * error, and > 0 if there was no room in the right hand block.
1300 *
1301 * this will only push up to 1/2 the contents of the left node over
1302 */
1303 static int balance_node_right(struct btrfs_trans_handle *trans,
1304 struct btrfs_root *root,
1305 struct extent_buffer *dst,
1306 struct extent_buffer *src)
1307 {
1308 int push_items = 0;
1309 int max_push;
1310 int src_nritems;
1311 int dst_nritems;
1312 int ret = 0;
1313
1314 WARN_ON(btrfs_header_generation(src) != trans->transid);
1315 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1316
1317 src_nritems = btrfs_header_nritems(src);
1318 dst_nritems = btrfs_header_nritems(dst);
1319 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1320 if (push_items <= 0) {
1321 return 1;
1322 }
1323
1324 if (src_nritems < 4) {
1325 return 1;
1326 }
1327
1328 max_push = src_nritems / 2 + 1;
1329 /* don't try to empty the node */
1330 if (max_push >= src_nritems) {
1331 return 1;
1332 }
1333
1334 if (max_push < push_items)
1335 push_items = max_push;
1336
1337 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1338 btrfs_node_key_ptr_offset(0),
1339 (dst_nritems) *
1340 sizeof(struct btrfs_key_ptr));
1341
1342 copy_extent_buffer(dst, src,
1343 btrfs_node_key_ptr_offset(0),
1344 btrfs_node_key_ptr_offset(src_nritems - push_items),
1345 push_items * sizeof(struct btrfs_key_ptr));
1346
1347 btrfs_set_header_nritems(src, src_nritems - push_items);
1348 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1349
1350 btrfs_mark_buffer_dirty(src);
1351 btrfs_mark_buffer_dirty(dst);
1352
1353 ret = btrfs_update_ref(trans, root, src, dst, 0, push_items);
1354 BUG_ON(ret);
1355 return ret;
1356 }
1357
1358 /*
1359 * helper function to insert a new root level in the tree.
1360 * A new node is allocated, and a single item is inserted to
1361 * point to the existing root
1362 *
1363 * returns zero on success or < 0 on failure.
1364 */
1365 static int noinline insert_new_root(struct btrfs_trans_handle *trans,
1366 struct btrfs_root *root,
1367 struct btrfs_path *path, int level)
1368 {
1369 u64 lower_gen;
1370 struct extent_buffer *lower;
1371 struct extent_buffer *c;
1372 struct extent_buffer *old;
1373 struct btrfs_disk_key lower_key;
1374 int ret;
1375
1376 BUG_ON(path->nodes[level]);
1377 BUG_ON(path->nodes[level-1] != root->node);
1378
1379 lower = path->nodes[level-1];
1380 if (level == 1)
1381 btrfs_item_key(lower, &lower_key, 0);
1382 else
1383 btrfs_node_key(lower, &lower_key, 0);
1384
1385 c = btrfs_alloc_free_block(trans, root, root->nodesize, 0,
1386 root->root_key.objectid,
1387 trans->transid, level,
1388 root->node->start, 0);
1389 if (IS_ERR(c))
1390 return PTR_ERR(c);
1391
1392 memset_extent_buffer(c, 0, 0, root->nodesize);
1393 btrfs_set_header_nritems(c, 1);
1394 btrfs_set_header_level(c, level);
1395 btrfs_set_header_bytenr(c, c->start);
1396 btrfs_set_header_generation(c, trans->transid);
1397 btrfs_set_header_owner(c, root->root_key.objectid);
1398
1399 write_extent_buffer(c, root->fs_info->fsid,
1400 (unsigned long)btrfs_header_fsid(c),
1401 BTRFS_FSID_SIZE);
1402
1403 write_extent_buffer(c, root->fs_info->chunk_tree_uuid,
1404 (unsigned long)btrfs_header_chunk_tree_uuid(c),
1405 BTRFS_UUID_SIZE);
1406
1407 btrfs_set_node_key(c, &lower_key, 0);
1408 btrfs_set_node_blockptr(c, 0, lower->start);
1409 lower_gen = btrfs_header_generation(lower);
1410 WARN_ON(lower_gen != trans->transid);
1411
1412 btrfs_set_node_ptr_generation(c, 0, lower_gen);
1413
1414 btrfs_mark_buffer_dirty(c);
1415
1416 old = root->node;
1417 root->node = c;
1418
1419 ret = btrfs_update_extent_ref(trans, root, lower->start,
1420 lower->start, c->start,
1421 root->root_key.objectid,
1422 trans->transid, level - 1);
1423 BUG_ON(ret);
1424
1425 /* the super has an extra ref to root->node */
1426 free_extent_buffer(old);
1427
1428 add_root_to_dirty_list(root);
1429 extent_buffer_get(c);
1430 path->nodes[level] = c;
1431 path->slots[level] = 0;
1432 return 0;
1433 }
1434
1435 /*
1436 * worker function to insert a single pointer in a node.
1437 * the node should have enough room for the pointer already
1438 *
1439 * slot and level indicate where you want the key to go, and
1440 * blocknr is the block the key points to.
1441 *
1442 * returns zero on success and < 0 on any error
1443 */
1444 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1445 *root, struct btrfs_path *path, struct btrfs_disk_key
1446 *key, u64 bytenr, int slot, int level)
1447 {
1448 struct extent_buffer *lower;
1449 int nritems;
1450
1451 BUG_ON(!path->nodes[level]);
1452 lower = path->nodes[level];
1453 nritems = btrfs_header_nritems(lower);
1454 if (slot > nritems)
1455 BUG();
1456 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1457 BUG();
1458 if (slot != nritems) {
1459 memmove_extent_buffer(lower,
1460 btrfs_node_key_ptr_offset(slot + 1),
1461 btrfs_node_key_ptr_offset(slot),
1462 (nritems - slot) * sizeof(struct btrfs_key_ptr));
1463 }
1464 btrfs_set_node_key(lower, key, slot);
1465 btrfs_set_node_blockptr(lower, slot, bytenr);
1466 WARN_ON(trans->transid == 0);
1467 btrfs_set_node_ptr_generation(lower, slot, trans->transid);
1468 btrfs_set_header_nritems(lower, nritems + 1);
1469 btrfs_mark_buffer_dirty(lower);
1470 return 0;
1471 }
1472
1473 /*
1474 * split the node at the specified level in path in two.
1475 * The path is corrected to point to the appropriate node after the split
1476 *
1477 * Before splitting this tries to make some room in the node by pushing
1478 * left and right, if either one works, it returns right away.
1479 *
1480 * returns 0 on success and < 0 on failure
1481 */
1482 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1483 *root, struct btrfs_path *path, int level)
1484 {
1485 struct extent_buffer *c;
1486 struct extent_buffer *split;
1487 struct btrfs_disk_key disk_key;
1488 int mid;
1489 int ret;
1490 int wret;
1491 u32 c_nritems;
1492
1493 c = path->nodes[level];
1494 WARN_ON(btrfs_header_generation(c) != trans->transid);
1495 if (c == root->node) {
1496 /* trying to split the root, lets make a new one */
1497 ret = insert_new_root(trans, root, path, level + 1);
1498 if (ret)
1499 return ret;
1500 } else {
1501 ret = push_nodes_for_insert(trans, root, path, level);
1502 c = path->nodes[level];
1503 if (!ret && btrfs_header_nritems(c) <
1504 BTRFS_NODEPTRS_PER_BLOCK(root) - 3)
1505 return 0;
1506 if (ret < 0)
1507 return ret;
1508 }
1509
1510 c_nritems = btrfs_header_nritems(c);
1511
1512 btrfs_node_key(c, &disk_key, 0);
1513 split = btrfs_alloc_free_block(trans, root, root->nodesize,
1514 path->nodes[level + 1]->start,
1515 root->root_key.objectid,
1516 trans->transid, level, c->start, 0);
1517 if (IS_ERR(split))
1518 return PTR_ERR(split);
1519
1520 btrfs_set_header_flags(split, btrfs_header_flags(c));
1521 btrfs_set_header_level(split, btrfs_header_level(c));
1522 btrfs_set_header_bytenr(split, split->start);
1523 btrfs_set_header_generation(split, trans->transid);
1524 btrfs_set_header_owner(split, root->root_key.objectid);
1525 btrfs_set_header_flags(split, 0);
1526 write_extent_buffer(split, root->fs_info->fsid,
1527 (unsigned long)btrfs_header_fsid(split),
1528 BTRFS_FSID_SIZE);
1529 write_extent_buffer(split, root->fs_info->chunk_tree_uuid,
1530 (unsigned long)btrfs_header_chunk_tree_uuid(split),
1531 BTRFS_UUID_SIZE);
1532
1533 mid = (c_nritems + 1) / 2;
1534
1535 copy_extent_buffer(split, c,
1536 btrfs_node_key_ptr_offset(0),
1537 btrfs_node_key_ptr_offset(mid),
1538 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1539 btrfs_set_header_nritems(split, c_nritems - mid);
1540 btrfs_set_header_nritems(c, mid);
1541 ret = 0;
1542
1543 btrfs_mark_buffer_dirty(c);
1544 btrfs_mark_buffer_dirty(split);
1545
1546 btrfs_node_key(split, &disk_key, 0);
1547 wret = insert_ptr(trans, root, path, &disk_key, split->start,
1548 path->slots[level + 1] + 1,
1549 level + 1);
1550 if (wret)
1551 ret = wret;
1552
1553 ret = btrfs_update_ref(trans, root, c, split, 0, c_nritems - mid);
1554 BUG_ON(ret);
1555
1556 if (path->slots[level] >= mid) {
1557 path->slots[level] -= mid;
1558 free_extent_buffer(c);
1559 path->nodes[level] = split;
1560 path->slots[level + 1] += 1;
1561 } else {
1562 free_extent_buffer(split);
1563 }
1564 return ret;
1565 }
1566
1567 /*
1568 * how many bytes are required to store the items in a leaf. start
1569 * and nr indicate which items in the leaf to check. This totals up the
1570 * space used both by the item structs and the item data
1571 */
1572 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1573 {
1574 int data_len;
1575 int nritems = btrfs_header_nritems(l);
1576 int end = min(nritems, start + nr) - 1;
1577
1578 if (!nr)
1579 return 0;
1580 data_len = btrfs_item_end_nr(l, start);
1581 data_len = data_len - btrfs_item_offset_nr(l, end);
1582 data_len += sizeof(struct btrfs_item) * nr;
1583 WARN_ON(data_len < 0);
1584 return data_len;
1585 }
1586
1587 /*
1588 * The space between the end of the leaf items and
1589 * the start of the leaf data. IOW, how much room
1590 * the leaf has left for both items and data
1591 */
1592 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1593 {
1594 int nritems = btrfs_header_nritems(leaf);
1595 int ret;
1596 ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1597 if (ret < 0) {
1598 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1599 ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
1600 leaf_space_used(leaf, 0, nritems), nritems);
1601 }
1602 return ret;
1603 }
1604
1605 /*
1606 * push some data in the path leaf to the right, trying to free up at
1607 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1608 *
1609 * returns 1 if the push failed because the other node didn't have enough
1610 * room, 0 if everything worked out and < 0 if there were major errors.
1611 */
1612 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1613 *root, struct btrfs_path *path, int data_size,
1614 int empty)
1615 {
1616 struct extent_buffer *left = path->nodes[0];
1617 struct extent_buffer *right;
1618 struct extent_buffer *upper;
1619 struct btrfs_disk_key disk_key;
1620 int slot;
1621 u32 i;
1622 int free_space;
1623 int push_space = 0;
1624 int push_items = 0;
1625 struct btrfs_item *item;
1626 u32 left_nritems;
1627 u32 nr;
1628 u32 right_nritems;
1629 u32 data_end;
1630 u32 this_item_size;
1631 int ret;
1632
1633 slot = path->slots[1];
1634 if (!path->nodes[1]) {
1635 return 1;
1636 }
1637 upper = path->nodes[1];
1638 if (slot >= btrfs_header_nritems(upper) - 1)
1639 return 1;
1640
1641 right = read_node_slot(root, upper, slot + 1);
1642 free_space = btrfs_leaf_free_space(root, right);
1643 if (free_space < data_size + sizeof(struct btrfs_item)) {
1644 free_extent_buffer(right);
1645 return 1;
1646 }
1647
1648 /* cow and double check */
1649 ret = btrfs_cow_block(trans, root, right, upper,
1650 slot + 1, &right);
1651 if (ret) {
1652 free_extent_buffer(right);
1653 return 1;
1654 }
1655 free_space = btrfs_leaf_free_space(root, right);
1656 if (free_space < data_size + sizeof(struct btrfs_item)) {
1657 free_extent_buffer(right);
1658 return 1;
1659 }
1660
1661 left_nritems = btrfs_header_nritems(left);
1662 if (left_nritems == 0) {
1663 free_extent_buffer(right);
1664 return 1;
1665 }
1666
1667 if (empty)
1668 nr = 0;
1669 else
1670 nr = 1;
1671
1672 i = left_nritems - 1;
1673 while (i >= nr) {
1674 item = btrfs_item_nr(left, i);
1675
1676 if (path->slots[0] == i)
1677 push_space += data_size + sizeof(*item);
1678
1679 this_item_size = btrfs_item_size(left, item);
1680 if (this_item_size + sizeof(*item) + push_space > free_space)
1681 break;
1682 push_items++;
1683 push_space += this_item_size + sizeof(*item);
1684 if (i == 0)
1685 break;
1686 i--;
1687 }
1688
1689 if (push_items == 0) {
1690 free_extent_buffer(right);
1691 return 1;
1692 }
1693
1694 if (!empty && push_items == left_nritems)
1695 WARN_ON(1);
1696
1697 /* push left to right */
1698 right_nritems = btrfs_header_nritems(right);
1699
1700 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1701 push_space -= leaf_data_end(root, left);
1702
1703 /* make room in the right data area */
1704 data_end = leaf_data_end(root, right);
1705 memmove_extent_buffer(right,
1706 btrfs_leaf_data(right) + data_end - push_space,
1707 btrfs_leaf_data(right) + data_end,
1708 BTRFS_LEAF_DATA_SIZE(root) - data_end);
1709
1710 /* copy from the left data area */
1711 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1712 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1713 btrfs_leaf_data(left) + leaf_data_end(root, left),
1714 push_space);
1715
1716 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1717 btrfs_item_nr_offset(0),
1718 right_nritems * sizeof(struct btrfs_item));
1719
1720 /* copy the items from left to right */
1721 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1722 btrfs_item_nr_offset(left_nritems - push_items),
1723 push_items * sizeof(struct btrfs_item));
1724
1725 /* update the item pointers */
1726 right_nritems += push_items;
1727 btrfs_set_header_nritems(right, right_nritems);
1728 push_space = BTRFS_LEAF_DATA_SIZE(root);
1729 for (i = 0; i < right_nritems; i++) {
1730 item = btrfs_item_nr(right, i);
1731 push_space -= btrfs_item_size(right, item);
1732 btrfs_set_item_offset(right, item, push_space);
1733 }
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 ret = btrfs_update_ref(trans, root, left, right, 0, push_items);
1747 BUG_ON(ret);
1748
1749 /* then fixup the leaf pointer in the path */
1750 if (path->slots[0] >= left_nritems) {
1751 path->slots[0] -= left_nritems;
1752 free_extent_buffer(path->nodes[0]);
1753 path->nodes[0] = right;
1754 path->slots[1] += 1;
1755 } else {
1756 free_extent_buffer(right);
1757 }
1758 return 0;
1759 }
1760 /*
1761 * push some data in the path leaf to the left, trying to free up at
1762 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1763 */
1764 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1765 *root, struct btrfs_path *path, int data_size,
1766 int empty)
1767 {
1768 struct btrfs_disk_key disk_key;
1769 struct extent_buffer *right = path->nodes[0];
1770 struct extent_buffer *left;
1771 int slot;
1772 int i;
1773 int free_space;
1774 int push_space = 0;
1775 int push_items = 0;
1776 struct btrfs_item *item;
1777 u32 old_left_nritems;
1778 u32 right_nritems;
1779 u32 nr;
1780 int ret = 0;
1781 int wret;
1782 u32 this_item_size;
1783 u32 old_left_item_size;
1784
1785 slot = path->slots[1];
1786 if (slot == 0)
1787 return 1;
1788 if (!path->nodes[1])
1789 return 1;
1790
1791 right_nritems = btrfs_header_nritems(right);
1792 if (right_nritems == 0) {
1793 return 1;
1794 }
1795
1796 left = read_node_slot(root, path->nodes[1], slot - 1);
1797 free_space = btrfs_leaf_free_space(root, left);
1798 if (free_space < data_size + sizeof(struct btrfs_item)) {
1799 free_extent_buffer(left);
1800 return 1;
1801 }
1802
1803 /* cow and double check */
1804 ret = btrfs_cow_block(trans, root, left,
1805 path->nodes[1], slot - 1, &left);
1806 if (ret) {
1807 /* we hit -ENOSPC, but it isn't fatal here */
1808 free_extent_buffer(left);
1809 return 1;
1810 }
1811
1812 free_space = btrfs_leaf_free_space(root, left);
1813 if (free_space < data_size + sizeof(struct btrfs_item)) {
1814 free_extent_buffer(left);
1815 return 1;
1816 }
1817
1818 if (empty)
1819 nr = right_nritems;
1820 else
1821 nr = right_nritems - 1;
1822
1823 for (i = 0; i < nr; i++) {
1824 item = btrfs_item_nr(right, i);
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 (push_items == 0) {
1838 free_extent_buffer(left);
1839 return 1;
1840 }
1841 if (!empty && push_items == btrfs_header_nritems(right))
1842 WARN_ON(1);
1843
1844 /* push data from right to left */
1845 copy_extent_buffer(left, right,
1846 btrfs_item_nr_offset(btrfs_header_nritems(left)),
1847 btrfs_item_nr_offset(0),
1848 push_items * sizeof(struct btrfs_item));
1849
1850 push_space = BTRFS_LEAF_DATA_SIZE(root) -
1851 btrfs_item_offset_nr(right, push_items -1);
1852
1853 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
1854 leaf_data_end(root, left) - push_space,
1855 btrfs_leaf_data(right) +
1856 btrfs_item_offset_nr(right, push_items - 1),
1857 push_space);
1858 old_left_nritems = btrfs_header_nritems(left);
1859 BUG_ON(old_left_nritems < 0);
1860
1861 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
1862 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1863 u32 ioff;
1864
1865 item = btrfs_item_nr(left, i);
1866 ioff = btrfs_item_offset(left, item);
1867 btrfs_set_item_offset(left, item,
1868 ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
1869 }
1870 btrfs_set_header_nritems(left, old_left_nritems + push_items);
1871
1872 /* fixup right node */
1873 if (push_items > right_nritems) {
1874 printk("push items %d nr %u\n", push_items, right_nritems);
1875 WARN_ON(1);
1876 }
1877
1878 if (push_items < right_nritems) {
1879 push_space = btrfs_item_offset_nr(right, push_items - 1) -
1880 leaf_data_end(root, right);
1881 memmove_extent_buffer(right, btrfs_leaf_data(right) +
1882 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1883 btrfs_leaf_data(right) +
1884 leaf_data_end(root, right), push_space);
1885
1886 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
1887 btrfs_item_nr_offset(push_items),
1888 (btrfs_header_nritems(right) - push_items) *
1889 sizeof(struct btrfs_item));
1890 }
1891 right_nritems -= push_items;
1892 btrfs_set_header_nritems(right, right_nritems);
1893 push_space = BTRFS_LEAF_DATA_SIZE(root);
1894 for (i = 0; i < right_nritems; i++) {
1895 item = btrfs_item_nr(right, i);
1896 push_space = push_space - btrfs_item_size(right, item);
1897 btrfs_set_item_offset(right, item, push_space);
1898 }
1899
1900 btrfs_mark_buffer_dirty(left);
1901 if (right_nritems)
1902 btrfs_mark_buffer_dirty(right);
1903
1904 btrfs_item_key(right, &disk_key, 0);
1905 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1906 if (wret)
1907 ret = wret;
1908
1909 ret = btrfs_update_ref(trans, root, right, left,
1910 old_left_nritems, push_items);
1911 BUG_ON(ret);
1912
1913 /* then fixup the leaf pointer in the path */
1914 if (path->slots[0] < push_items) {
1915 path->slots[0] += old_left_nritems;
1916 free_extent_buffer(path->nodes[0]);
1917 path->nodes[0] = left;
1918 path->slots[1] -= 1;
1919 } else {
1920 free_extent_buffer(left);
1921 path->slots[0] -= push_items;
1922 }
1923 BUG_ON(path->slots[0] < 0);
1924 return ret;
1925 }
1926
1927 /*
1928 * split the path's leaf in two, making sure there is at least data_size
1929 * available for the resulting leaf level of the path.
1930 *
1931 * returns 0 if all went well and < 0 on failure.
1932 */
1933 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1934 *root, struct btrfs_key *ins_key,
1935 struct btrfs_path *path, int data_size, int extend)
1936 {
1937 struct extent_buffer *l;
1938 u32 nritems;
1939 int mid;
1940 int slot;
1941 struct extent_buffer *right;
1942 int space_needed = data_size + sizeof(struct btrfs_item);
1943 int data_copy_size;
1944 int rt_data_off;
1945 int i;
1946 int ret = 0;
1947 int wret;
1948 int double_split;
1949 int num_doubles = 0;
1950 struct btrfs_disk_key disk_key;
1951
1952 if (extend)
1953 space_needed = data_size;
1954
1955 /* first try to make some room by pushing left and right */
1956 if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
1957 wret = push_leaf_right(trans, root, path, data_size, 0);
1958 if (wret < 0) {
1959 return wret;
1960 }
1961 if (wret) {
1962 wret = push_leaf_left(trans, root, path, data_size, 0);
1963 if (wret < 0)
1964 return wret;
1965 }
1966 l = path->nodes[0];
1967
1968 /* did the pushes work? */
1969 if (btrfs_leaf_free_space(root, l) >= space_needed)
1970 return 0;
1971 }
1972
1973 if (!path->nodes[1]) {
1974 ret = insert_new_root(trans, root, path, 1);
1975 if (ret)
1976 return ret;
1977 }
1978 again:
1979 double_split = 0;
1980 l = path->nodes[0];
1981 slot = path->slots[0];
1982 nritems = btrfs_header_nritems(l);
1983 mid = (nritems + 1)/ 2;
1984
1985 right = btrfs_alloc_free_block(trans, root, root->leafsize,
1986 path->nodes[1]->start,
1987 root->root_key.objectid,
1988 trans->transid, 0, l->start, 0);
1989 if (IS_ERR(right)) {
1990 BUG_ON(1);
1991 return PTR_ERR(right);
1992 }
1993
1994 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
1995 btrfs_set_header_bytenr(right, right->start);
1996 btrfs_set_header_generation(right, trans->transid);
1997 btrfs_set_header_owner(right, root->root_key.objectid);
1998 btrfs_set_header_level(right, 0);
1999 write_extent_buffer(right, root->fs_info->fsid,
2000 (unsigned long)btrfs_header_fsid(right),
2001 BTRFS_FSID_SIZE);
2002
2003 write_extent_buffer(right, root->fs_info->chunk_tree_uuid,
2004 (unsigned long)btrfs_header_chunk_tree_uuid(right),
2005 BTRFS_UUID_SIZE);
2006 if (mid <= slot) {
2007 if (nritems == 1 ||
2008 leaf_space_used(l, mid, nritems - mid) + space_needed >
2009 BTRFS_LEAF_DATA_SIZE(root)) {
2010 if (slot >= nritems) {
2011 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2012 btrfs_set_header_nritems(right, 0);
2013 wret = insert_ptr(trans, root, path,
2014 &disk_key, right->start,
2015 path->slots[1] + 1, 1);
2016 if (wret)
2017 ret = wret;
2018 free_extent_buffer(path->nodes[0]);
2019 path->nodes[0] = right;
2020 path->slots[0] = 0;
2021 path->slots[1] += 1;
2022 return ret;
2023 }
2024 mid = slot;
2025 if (mid != nritems &&
2026 leaf_space_used(l, mid, nritems - mid) +
2027 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2028 double_split = 1;
2029 }
2030 }
2031 } else {
2032 if (leaf_space_used(l, 0, mid + 1) + space_needed >
2033 BTRFS_LEAF_DATA_SIZE(root)) {
2034 if (!extend && slot == 0) {
2035 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2036 btrfs_set_header_nritems(right, 0);
2037 wret = insert_ptr(trans, root, path,
2038 &disk_key,
2039 right->start,
2040 path->slots[1], 1);
2041 if (wret)
2042 ret = wret;
2043 free_extent_buffer(path->nodes[0]);
2044 path->nodes[0] = right;
2045 path->slots[0] = 0;
2046 if (path->slots[1] == 0) {
2047 wret = fixup_low_keys(trans, root,
2048 path, &disk_key, 1);
2049 if (wret)
2050 ret = wret;
2051 }
2052 return ret;
2053 } else if (extend && slot == 0) {
2054 mid = 1;
2055 } else {
2056 mid = slot;
2057 if (mid != nritems &&
2058 leaf_space_used(l, mid, nritems - mid) +
2059 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2060 double_split = 1;
2061 }
2062 }
2063 }
2064 }
2065 nritems = nritems - mid;
2066 btrfs_set_header_nritems(right, nritems);
2067 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
2068
2069 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
2070 btrfs_item_nr_offset(mid),
2071 nritems * sizeof(struct btrfs_item));
2072
2073 copy_extent_buffer(right, l,
2074 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
2075 data_copy_size, btrfs_leaf_data(l) +
2076 leaf_data_end(root, l), data_copy_size);
2077
2078 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
2079 btrfs_item_end_nr(l, mid);
2080
2081 for (i = 0; i < nritems; i++) {
2082 struct btrfs_item *item = btrfs_item_nr(right, i);
2083 u32 ioff = btrfs_item_offset(right, item);
2084 btrfs_set_item_offset(right, item, ioff + rt_data_off);
2085 }
2086
2087 btrfs_set_header_nritems(l, mid);
2088 ret = 0;
2089 btrfs_item_key(right, &disk_key, 0);
2090 wret = insert_ptr(trans, root, path, &disk_key, right->start,
2091 path->slots[1] + 1, 1);
2092 if (wret)
2093 ret = wret;
2094
2095 btrfs_mark_buffer_dirty(right);
2096 btrfs_mark_buffer_dirty(l);
2097 BUG_ON(path->slots[0] != slot);
2098
2099 ret = btrfs_update_ref(trans, root, l, right, 0, nritems);
2100 BUG_ON(ret);
2101
2102 if (mid <= slot) {
2103 free_extent_buffer(path->nodes[0]);
2104 path->nodes[0] = right;
2105 path->slots[0] -= mid;
2106 path->slots[1] += 1;
2107 } else
2108 free_extent_buffer(right);
2109
2110 BUG_ON(path->slots[0] < 0);
2111
2112 if (double_split) {
2113 BUG_ON(num_doubles != 0);
2114 num_doubles++;
2115 goto again;
2116 }
2117 return ret;
2118 }
2119
2120 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
2121 struct btrfs_root *root,
2122 struct btrfs_path *path,
2123 u32 new_size, int from_end)
2124 {
2125 int ret = 0;
2126 int slot;
2127 int slot_orig;
2128 struct extent_buffer *leaf;
2129 struct btrfs_item *item;
2130 u32 nritems;
2131 unsigned int data_end;
2132 unsigned int old_data_start;
2133 unsigned int old_size;
2134 unsigned int size_diff;
2135 int i;
2136
2137 slot_orig = path->slots[0];
2138 leaf = path->nodes[0];
2139 slot = path->slots[0];
2140
2141 old_size = btrfs_item_size_nr(leaf, slot);
2142 if (old_size == new_size)
2143 return 0;
2144
2145 nritems = btrfs_header_nritems(leaf);
2146 data_end = leaf_data_end(root, leaf);
2147
2148 old_data_start = btrfs_item_offset_nr(leaf, slot);
2149
2150 size_diff = old_size - new_size;
2151
2152 BUG_ON(slot < 0);
2153 BUG_ON(slot >= nritems);
2154
2155 /*
2156 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2157 */
2158 /* first correct the data pointers */
2159 for (i = slot; i < nritems; i++) {
2160 u32 ioff;
2161 item = btrfs_item_nr(leaf, i);
2162 ioff = btrfs_item_offset(leaf, item);
2163 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2164 }
2165
2166 /* shift the data */
2167 if (from_end) {
2168 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2169 data_end + size_diff, btrfs_leaf_data(leaf) +
2170 data_end, old_data_start + new_size - data_end);
2171 } else {
2172 struct btrfs_disk_key disk_key;
2173 u64 offset;
2174
2175 btrfs_item_key(leaf, &disk_key, slot);
2176
2177 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2178 unsigned long ptr;
2179 struct btrfs_file_extent_item *fi;
2180
2181 fi = btrfs_item_ptr(leaf, slot,
2182 struct btrfs_file_extent_item);
2183 fi = (struct btrfs_file_extent_item *)(
2184 (unsigned long)fi - size_diff);
2185
2186 if (btrfs_file_extent_type(leaf, fi) ==
2187 BTRFS_FILE_EXTENT_INLINE) {
2188 ptr = btrfs_item_ptr_offset(leaf, slot);
2189 memmove_extent_buffer(leaf, ptr,
2190 (unsigned long)fi,
2191 offsetof(struct btrfs_file_extent_item,
2192 disk_bytenr));
2193 }
2194 }
2195
2196 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2197 data_end + size_diff, btrfs_leaf_data(leaf) +
2198 data_end, old_data_start - data_end);
2199
2200 offset = btrfs_disk_key_offset(&disk_key);
2201 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2202 btrfs_set_item_key(leaf, &disk_key, slot);
2203 if (slot == 0)
2204 fixup_low_keys(trans, root, path, &disk_key, 1);
2205 }
2206
2207 item = btrfs_item_nr(leaf, slot);
2208 btrfs_set_item_size(leaf, item, new_size);
2209 btrfs_mark_buffer_dirty(leaf);
2210
2211 ret = 0;
2212 if (btrfs_leaf_free_space(root, leaf) < 0) {
2213 btrfs_print_leaf(root, leaf);
2214 BUG();
2215 }
2216 return ret;
2217 }
2218
2219 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2220 struct btrfs_root *root, struct btrfs_path *path,
2221 u32 data_size)
2222 {
2223 int ret = 0;
2224 int slot;
2225 int slot_orig;
2226 struct extent_buffer *leaf;
2227 struct btrfs_item *item;
2228 u32 nritems;
2229 unsigned int data_end;
2230 unsigned int old_data;
2231 unsigned int old_size;
2232 int i;
2233
2234 slot_orig = path->slots[0];
2235 leaf = path->nodes[0];
2236
2237 nritems = btrfs_header_nritems(leaf);
2238 data_end = leaf_data_end(root, leaf);
2239
2240 if (btrfs_leaf_free_space(root, leaf) < data_size) {
2241 btrfs_print_leaf(root, leaf);
2242 BUG();
2243 }
2244 slot = path->slots[0];
2245 old_data = btrfs_item_end_nr(leaf, slot);
2246
2247 BUG_ON(slot < 0);
2248 if (slot >= nritems) {
2249 btrfs_print_leaf(root, leaf);
2250 printk("slot %d too large, nritems %d\n", slot, nritems);
2251 BUG_ON(1);
2252 }
2253
2254 /*
2255 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2256 */
2257 /* first correct the data pointers */
2258 for (i = slot; i < nritems; i++) {
2259 u32 ioff;
2260 item = btrfs_item_nr(leaf, i);
2261 ioff = btrfs_item_offset(leaf, item);
2262 btrfs_set_item_offset(leaf, item, ioff - data_size);
2263 }
2264
2265 /* shift the data */
2266 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2267 data_end - data_size, btrfs_leaf_data(leaf) +
2268 data_end, old_data - data_end);
2269
2270 data_end = old_data;
2271 old_size = btrfs_item_size_nr(leaf, slot);
2272 item = btrfs_item_nr(leaf, slot);
2273 btrfs_set_item_size(leaf, item, old_size + data_size);
2274 btrfs_mark_buffer_dirty(leaf);
2275
2276 ret = 0;
2277 if (btrfs_leaf_free_space(root, leaf) < 0) {
2278 btrfs_print_leaf(root, leaf);
2279 BUG();
2280 }
2281 return ret;
2282 }
2283
2284 /*
2285 * Given a key and some data, insert an item into the tree.
2286 * This does all the path init required, making room in the tree if needed.
2287 */
2288 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
2289 struct btrfs_root *root,
2290 struct btrfs_path *path,
2291 struct btrfs_key *cpu_key, u32 *data_size,
2292 int nr)
2293 {
2294 struct extent_buffer *leaf;
2295 struct btrfs_item *item;
2296 int ret = 0;
2297 int slot;
2298 int slot_orig;
2299 int i;
2300 u32 nritems;
2301 u32 total_size = 0;
2302 u32 total_data = 0;
2303 unsigned int data_end;
2304 struct btrfs_disk_key disk_key;
2305
2306 for (i = 0; i < nr; i++) {
2307 total_data += data_size[i];
2308 }
2309
2310 /* create a root if there isn't one */
2311 if (!root->node)
2312 BUG();
2313
2314 total_size = total_data + (nr - 1) * sizeof(struct btrfs_item);
2315 ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
2316 if (ret == 0) {
2317 return -EEXIST;
2318 }
2319 if (ret < 0)
2320 goto out;
2321
2322 slot_orig = path->slots[0];
2323 leaf = path->nodes[0];
2324
2325 nritems = btrfs_header_nritems(leaf);
2326 data_end = leaf_data_end(root, leaf);
2327
2328 if (btrfs_leaf_free_space(root, leaf) <
2329 sizeof(struct btrfs_item) + total_size) {
2330 btrfs_print_leaf(root, leaf);
2331 printk("not enough freespace need %u have %d\n",
2332 total_size, btrfs_leaf_free_space(root, leaf));
2333 BUG();
2334 }
2335
2336 slot = path->slots[0];
2337 BUG_ON(slot < 0);
2338
2339 if (slot != nritems) {
2340 int i;
2341 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2342
2343 if (old_data < data_end) {
2344 btrfs_print_leaf(root, leaf);
2345 printk("slot %d old_data %d data_end %d\n",
2346 slot, old_data, data_end);
2347 BUG_ON(1);
2348 }
2349 /*
2350 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2351 */
2352 /* first correct the data pointers */
2353 for (i = slot; i < nritems; i++) {
2354 u32 ioff;
2355
2356 item = btrfs_item_nr(leaf, i);
2357 ioff = btrfs_item_offset(leaf, item);
2358 btrfs_set_item_offset(leaf, item, ioff - total_data);
2359 }
2360
2361 /* shift the items */
2362 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
2363 btrfs_item_nr_offset(slot),
2364 (nritems - slot) * sizeof(struct btrfs_item));
2365
2366 /* shift the data */
2367 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2368 data_end - total_data, btrfs_leaf_data(leaf) +
2369 data_end, old_data - data_end);
2370 data_end = old_data;
2371 }
2372
2373 /* setup the item for the new data */
2374 for (i = 0; i < nr; i++) {
2375 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
2376 btrfs_set_item_key(leaf, &disk_key, slot + i);
2377 item = btrfs_item_nr(leaf, slot + i);
2378 btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
2379 data_end -= data_size[i];
2380 btrfs_set_item_size(leaf, item, data_size[i]);
2381 }
2382 btrfs_set_header_nritems(leaf, nritems + nr);
2383 btrfs_mark_buffer_dirty(leaf);
2384
2385 ret = 0;
2386 if (slot == 0) {
2387 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2388 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2389 }
2390
2391 if (btrfs_leaf_free_space(root, leaf) < 0) {
2392 btrfs_print_leaf(root, leaf);
2393 BUG();
2394 }
2395
2396 out:
2397 return ret;
2398 }
2399
2400 /*
2401 * Given a key and some data, insert an item into the tree.
2402 * This does all the path init required, making room in the tree if needed.
2403 */
2404 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2405 *root, struct btrfs_key *cpu_key, void *data, u32
2406 data_size)
2407 {
2408 int ret = 0;
2409 struct btrfs_path *path;
2410 struct extent_buffer *leaf;
2411 unsigned long ptr;
2412
2413 path = btrfs_alloc_path();
2414 BUG_ON(!path);
2415 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2416 if (!ret) {
2417 leaf = path->nodes[0];
2418 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2419 write_extent_buffer(leaf, data, ptr, data_size);
2420 btrfs_mark_buffer_dirty(leaf);
2421 }
2422 btrfs_free_path(path);
2423 return ret;
2424 }
2425
2426 /*
2427 * delete the pointer from a given node.
2428 *
2429 * If the delete empties a node, the node is removed from the tree,
2430 * continuing all the way the root if required. The root is converted into
2431 * a leaf if all the nodes are emptied.
2432 */
2433 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2434 struct btrfs_path *path, int level, int slot)
2435 {
2436 struct extent_buffer *parent = path->nodes[level];
2437 u32 nritems;
2438 int ret = 0;
2439 int wret;
2440
2441 nritems = btrfs_header_nritems(parent);
2442 if (slot != nritems -1) {
2443 memmove_extent_buffer(parent,
2444 btrfs_node_key_ptr_offset(slot),
2445 btrfs_node_key_ptr_offset(slot + 1),
2446 sizeof(struct btrfs_key_ptr) *
2447 (nritems - slot - 1));
2448 }
2449 nritems--;
2450 btrfs_set_header_nritems(parent, nritems);
2451 if (nritems == 0 && parent == root->node) {
2452 BUG_ON(btrfs_header_level(root->node) != 1);
2453 /* just turn the root into a leaf and break */
2454 btrfs_set_header_level(root->node, 0);
2455 } else if (slot == 0) {
2456 struct btrfs_disk_key disk_key;
2457
2458 btrfs_node_key(parent, &disk_key, 0);
2459 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2460 if (wret)
2461 ret = wret;
2462 }
2463 btrfs_mark_buffer_dirty(parent);
2464 return ret;
2465 }
2466
2467 /*
2468 * delete the item at the leaf level in path. If that empties
2469 * the leaf, remove it from the tree
2470 */
2471 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2472 struct btrfs_path *path, int slot, int nr)
2473 {
2474 struct extent_buffer *leaf;
2475 struct btrfs_item *item;
2476 int last_off;
2477 int dsize = 0;
2478 int ret = 0;
2479 int wret;
2480 int i;
2481 u32 nritems;
2482
2483 leaf = path->nodes[0];
2484 last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
2485
2486 for (i = 0; i < nr; i++)
2487 dsize += btrfs_item_size_nr(leaf, slot + i);
2488
2489 nritems = btrfs_header_nritems(leaf);
2490
2491 if (slot + nr != nritems) {
2492 int i;
2493 int data_end = leaf_data_end(root, leaf);
2494
2495 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2496 data_end + dsize,
2497 btrfs_leaf_data(leaf) + data_end,
2498 last_off - data_end);
2499
2500 for (i = slot + nr; i < nritems; i++) {
2501 u32 ioff;
2502
2503 item = btrfs_item_nr(leaf, i);
2504 ioff = btrfs_item_offset(leaf, item);
2505 btrfs_set_item_offset(leaf, item, ioff + dsize);
2506 }
2507
2508 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2509 btrfs_item_nr_offset(slot + nr),
2510 sizeof(struct btrfs_item) *
2511 (nritems - slot - nr));
2512 }
2513 btrfs_set_header_nritems(leaf, nritems - nr);
2514 nritems -= nr;
2515
2516 /* delete the leaf if we've emptied it */
2517 if (nritems == 0) {
2518 if (leaf == root->node) {
2519 btrfs_set_header_level(leaf, 0);
2520 } else {
2521 u64 root_gen = btrfs_header_generation(path->nodes[1]);
2522 clean_tree_block(trans, root, leaf);
2523 wait_on_tree_block_writeback(root, leaf);
2524 wret = del_ptr(trans, root, path, 1, path->slots[1]);
2525 if (wret)
2526 ret = wret;
2527 wret = btrfs_free_extent(trans, root,
2528 leaf->start, leaf->len,
2529 path->nodes[1]->start,
2530 btrfs_header_owner(path->nodes[1]),
2531 root_gen, 0, 1);
2532 if (wret)
2533 ret = wret;
2534 }
2535 } else {
2536 int used = leaf_space_used(leaf, 0, nritems);
2537 if (slot == 0) {
2538 struct btrfs_disk_key disk_key;
2539
2540 btrfs_item_key(leaf, &disk_key, 0);
2541 wret = fixup_low_keys(trans, root, path,
2542 &disk_key, 1);
2543 if (wret)
2544 ret = wret;
2545 }
2546
2547 /* delete the leaf if it is mostly empty */
2548 if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
2549 /* push_leaf_left fixes the path.
2550 * make sure the path still points to our leaf
2551 * for possible call to del_ptr below
2552 */
2553 slot = path->slots[1];
2554 extent_buffer_get(leaf);
2555
2556 wret = push_leaf_left(trans, root, path, 1, 1);
2557 if (wret < 0 && wret != -ENOSPC)
2558 ret = wret;
2559
2560 if (path->nodes[0] == leaf &&
2561 btrfs_header_nritems(leaf)) {
2562 wret = push_leaf_right(trans, root, path, 1, 1);
2563 if (wret < 0 && wret != -ENOSPC)
2564 ret = wret;
2565 }
2566
2567 if (btrfs_header_nritems(leaf) == 0) {
2568 u64 root_gen;
2569 u64 bytenr = leaf->start;
2570 u32 blocksize = leaf->len;
2571
2572 root_gen = btrfs_header_generation(
2573 path->nodes[1]);
2574
2575 clean_tree_block(trans, root, leaf);
2576 wait_on_tree_block_writeback(root, leaf);
2577
2578 wret = del_ptr(trans, root, path, 1, slot);
2579 if (wret)
2580 ret = wret;
2581
2582 free_extent_buffer(leaf);
2583 wret = btrfs_free_extent(trans, root, bytenr,
2584 blocksize, path->nodes[1]->start,
2585 btrfs_header_owner(path->nodes[1]),
2586 root_gen, 0, 1);
2587 if (wret)
2588 ret = wret;
2589 } else {
2590 btrfs_mark_buffer_dirty(leaf);
2591 free_extent_buffer(leaf);
2592 }
2593 } else {
2594 btrfs_mark_buffer_dirty(leaf);
2595 }
2596 }
2597 return ret;
2598 }
2599
2600 /*
2601 * walk up the tree as far as required to find the previous leaf.
2602 * returns 0 if it found something or 1 if there are no lesser leaves.
2603 * returns < 0 on io errors.
2604 */
2605 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
2606 {
2607 int slot;
2608 int level = 1;
2609 struct extent_buffer *c;
2610 struct extent_buffer *next = NULL;
2611
2612 while(level < BTRFS_MAX_LEVEL) {
2613 if (!path->nodes[level])
2614 return 1;
2615
2616 slot = path->slots[level];
2617 c = path->nodes[level];
2618 if (slot == 0) {
2619 level++;
2620 if (level == BTRFS_MAX_LEVEL)
2621 return 1;
2622 continue;
2623 }
2624 slot--;
2625
2626 if (next)
2627 free_extent_buffer(next);
2628
2629 next = read_node_slot(root, c, slot);
2630 break;
2631 }
2632 path->slots[level] = slot;
2633 while(1) {
2634 level--;
2635 c = path->nodes[level];
2636 free_extent_buffer(c);
2637 slot = btrfs_header_nritems(next);
2638 if (slot != 0)
2639 slot--;
2640 path->nodes[level] = next;
2641 path->slots[level] = slot;
2642 if (!level)
2643 break;
2644 next = read_node_slot(root, next, slot);
2645 }
2646 return 0;
2647 }
2648
2649 /*
2650 * walk up the tree as far as required to find the next leaf.
2651 * returns 0 if it found something or 1 if there are no greater leaves.
2652 * returns < 0 on io errors.
2653 */
2654 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2655 {
2656 int slot;
2657 int level = 1;
2658 struct extent_buffer *c;
2659 struct extent_buffer *next = NULL;
2660
2661 while(level < BTRFS_MAX_LEVEL) {
2662 if (!path->nodes[level])
2663 return 1;
2664
2665 slot = path->slots[level] + 1;
2666 c = path->nodes[level];
2667 if (slot >= btrfs_header_nritems(c)) {
2668 level++;
2669 if (level == BTRFS_MAX_LEVEL)
2670 return 1;
2671 continue;
2672 }
2673
2674 if (next)
2675 free_extent_buffer(next);
2676
2677 if (path->reada)
2678 reada_for_search(root, path, level, slot, 0);
2679
2680 next = read_node_slot(root, c, slot);
2681 break;
2682 }
2683 path->slots[level] = slot;
2684 while(1) {
2685 level--;
2686 c = path->nodes[level];
2687 free_extent_buffer(c);
2688 path->nodes[level] = next;
2689 path->slots[level] = 0;
2690 if (!level)
2691 break;
2692 if (path->reada)
2693 reada_for_search(root, path, level, 0, 0);
2694 next = read_node_slot(root, next, 0);
2695 }
2696 return 0;
2697 }
2698
2699 int btrfs_previous_item(struct btrfs_root *root,
2700 struct btrfs_path *path, u64 min_objectid,
2701 int type)
2702 {
2703 struct btrfs_key found_key;
2704 struct extent_buffer *leaf;
2705 int ret;
2706
2707 while(1) {
2708 if (path->slots[0] == 0) {
2709 ret = btrfs_prev_leaf(root, path);
2710 if (ret != 0)
2711 return ret;
2712 } else {
2713 path->slots[0]--;
2714 }
2715 leaf = path->nodes[0];
2716 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2717 if (found_key.type == type)
2718 return 0;
2719 }
2720 return 1;
2721 }
2722
(deprecated) Btrfs progs developments and patch integration