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Update find_free_extent for the ext3 conversion tool
[btrfs-progs-unstable.git] / ctree.c
blob2f6bee1504dc6a708faa51680d3e2716cd461c6f
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 = kmalloc(sizeof(struct btrfs_path), GFP_NOFS);
49 if (path) {
50 btrfs_init_path(path);
51 path->reada = 0;
52 }
53 return path;
54 }
55
56 void btrfs_free_path(struct btrfs_path *p)
57 {
58 btrfs_release_path(NULL, p);
59 kfree(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 int btrfs_copy_root(struct btrfs_trans_handle *trans,
74 struct btrfs_root *root,
75 struct extent_buffer *buf,
76 struct extent_buffer **cow_ret, u64 new_root_objectid)
77 {
78 struct extent_buffer *cow;
79 u32 nritems;
80 int ret = 0;
81 int level;
82 struct btrfs_key first_key;
83 struct btrfs_root *new_root;
84
85 new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
86 if (!new_root)
87 return -ENOMEM;
88
89 memcpy(new_root, root, sizeof(*new_root));
90 new_root->root_key.objectid = new_root_objectid;
91
92 WARN_ON(root->ref_cows && trans->transid !=
93 root->fs_info->running_transaction->transid);
94 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
95
96 level = btrfs_header_level(buf);
97 nritems = btrfs_header_nritems(buf);
98 if (nritems) {
99 if (level == 0)
100 btrfs_item_key_to_cpu(buf, &first_key, 0);
101 else
102 btrfs_node_key_to_cpu(buf, &first_key, 0);
103 } else {
104 first_key.objectid = 0;
105 }
106 cow = __btrfs_alloc_free_block(trans, new_root, buf->len,
107 new_root_objectid,
108 trans->transid, first_key.objectid,
109 level, buf->start, 0);
110 if (IS_ERR(cow)) {
111 kfree(new_root);
112 return PTR_ERR(cow);
113 }
114
115 copy_extent_buffer(cow, buf, 0, 0, cow->len);
116 btrfs_set_header_bytenr(cow, cow->start);
117 btrfs_set_header_generation(cow, trans->transid);
118 btrfs_set_header_owner(cow, new_root_objectid);
119
120 WARN_ON(btrfs_header_generation(buf) > trans->transid);
121 ret = btrfs_inc_ref(trans, new_root, buf);
122 kfree(new_root);
123
124 if (ret)
125 return ret;
126
127 btrfs_mark_buffer_dirty(cow);
128 *cow_ret = cow;
129 return 0;
130 }
131
132 int __btrfs_cow_block(struct btrfs_trans_handle *trans,
133 struct btrfs_root *root,
134 struct extent_buffer *buf,
135 struct extent_buffer *parent, int parent_slot,
136 struct extent_buffer **cow_ret,
137 u64 search_start, u64 empty_size)
138 {
139 u64 root_gen;
140 struct extent_buffer *cow;
141 u32 nritems;
142 int ret = 0;
143 int different_trans = 0;
144 int level;
145 struct btrfs_key first_key;
146
147 if (root->ref_cows) {
148 root_gen = trans->transid;
149 } else {
150 root_gen = 0;
151 }
152
153 WARN_ON(root->ref_cows && trans->transid !=
154 root->fs_info->running_transaction->transid);
155 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
156
157 level = btrfs_header_level(buf);
158 nritems = btrfs_header_nritems(buf);
159 if (nritems) {
160 if (level == 0)
161 btrfs_item_key_to_cpu(buf, &first_key, 0);
162 else
163 btrfs_node_key_to_cpu(buf, &first_key, 0);
164 } else {
165 first_key.objectid = 0;
166 }
167 cow = __btrfs_alloc_free_block(trans, root, buf->len,
168 root->root_key.objectid,
169 root_gen, first_key.objectid, level,
170 search_start, empty_size);
171 if (IS_ERR(cow))
172 return PTR_ERR(cow);
173
174 copy_extent_buffer(cow, buf, 0, 0, cow->len);
175 btrfs_set_header_bytenr(cow, cow->start);
176 btrfs_set_header_generation(cow, trans->transid);
177 btrfs_set_header_owner(cow, root->root_key.objectid);
178
179 WARN_ON(btrfs_header_generation(buf) > trans->transid);
180 if (btrfs_header_generation(buf) != trans->transid) {
181 different_trans = 1;
182 ret = btrfs_inc_ref(trans, root, buf);
183 if (ret)
184 return ret;
185 } else {
186 clean_tree_block(trans, root, buf);
187 }
188
189 if (buf == root->node) {
190 root_gen = btrfs_header_generation(buf);
191 root->node = cow;
192 extent_buffer_get(cow);
193 if (buf != root->commit_root) {
194 btrfs_free_extent(trans, root, buf->start,
195 buf->len, root->root_key.objectid,
196 root_gen, 0, 0, 1);
197 }
198 free_extent_buffer(buf);
199 } else {
200 root_gen = btrfs_header_generation(parent);
201 btrfs_set_node_blockptr(parent, parent_slot,
202 cow->start);
203 WARN_ON(trans->transid == 0);
204 btrfs_set_node_ptr_generation(parent, parent_slot,
205 trans->transid);
206 btrfs_mark_buffer_dirty(parent);
207 WARN_ON(btrfs_header_generation(parent) != trans->transid);
208 btrfs_free_extent(trans, root, buf->start, buf->len,
209 btrfs_header_owner(parent), root_gen,
210 0, 0, 1);
211 }
212 free_extent_buffer(buf);
213 btrfs_mark_buffer_dirty(cow);
214 *cow_ret = cow;
215 return 0;
216 }
217
218 int btrfs_cow_block(struct btrfs_trans_handle *trans,
219 struct btrfs_root *root, struct extent_buffer *buf,
220 struct extent_buffer *parent, int parent_slot,
221 struct extent_buffer **cow_ret)
222 {
223 u64 search_start;
224 int ret;
225 /*
226 if (trans->transaction != root->fs_info->running_transaction) {
227 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
228 root->fs_info->running_transaction->transid);
229 WARN_ON(1);
230 }
231 */
232 if (trans->transid != root->fs_info->generation) {
233 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
234 root->fs_info->generation);
235 WARN_ON(1);
236 }
237 if (btrfs_header_generation(buf) == trans->transid) {
238 *cow_ret = buf;
239 return 0;
240 }
241
242 search_start = buf->start & ~((u64)BTRFS_BLOCK_GROUP_SIZE - 1);
243 ret = __btrfs_cow_block(trans, root, buf, parent,
244 parent_slot, cow_ret, search_start, 0);
245 return ret;
246 }
247
248 /*
249 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
250 {
251 if (blocknr < other && other - (blocknr + blocksize) < 32768)
252 return 1;
253 if (blocknr > other && blocknr - (other + blocksize) < 32768)
254 return 1;
255 return 0;
256 }
257 */
258
259 /*
260 * compare two keys in a memcmp fashion
261 */
262 int btrfs_comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
263 {
264 struct btrfs_key k1;
265
266 btrfs_disk_key_to_cpu(&k1, disk);
267
268 if (k1.objectid > k2->objectid)
269 return 1;
270 if (k1.objectid < k2->objectid)
271 return -1;
272 if (k1.type > k2->type)
273 return 1;
274 if (k1.type < k2->type)
275 return -1;
276 if (k1.offset > k2->offset)
277 return 1;
278 if (k1.offset < k2->offset)
279 return -1;
280 return 0;
281 }
282
283
284 #if 0
285 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
286 struct btrfs_root *root, struct extent_buffer *parent,
287 int start_slot, int cache_only, u64 *last_ret,
288 struct btrfs_key *progress)
289 {
290 struct extent_buffer *cur;
291 struct extent_buffer *tmp;
292 u64 blocknr;
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 if (last_block == 0)
346 last_block = blocknr;
347
348 if (i > 0) {
349 other = btrfs_node_blockptr(parent, i - 1);
350 close = close_blocks(blocknr, other, blocksize);
351 }
352 if (close && i < end_slot - 2) {
353 other = btrfs_node_blockptr(parent, i + 1);
354 close = close_blocks(blocknr, other, blocksize);
355 }
356 if (close) {
357 last_block = blocknr;
358 continue;
359 }
360 if (parent->map_token) {
361 unmap_extent_buffer(parent, parent->map_token,
362 KM_USER1);
363 parent->map_token = NULL;
364 }
365
366 cur = btrfs_find_tree_block(root, blocknr, blocksize);
367 if (cur)
368 uptodate = btrfs_buffer_uptodate(cur);
369 else
370 uptodate = 0;
371 if (!cur || !uptodate) {
372 if (cache_only) {
373 free_extent_buffer(cur);
374 continue;
375 }
376 if (!cur) {
377 cur = read_tree_block(root, blocknr,
378 blocksize);
379 } else if (!uptodate) {
380 btrfs_read_buffer(cur);
381 }
382 }
383 if (search_start == 0)
384 search_start = last_block;
385
386 err = __btrfs_cow_block(trans, root, cur, parent, i,
387 &tmp, search_start,
388 min(16 * blocksize,
389 (end_slot - i) * blocksize));
390 if (err) {
391 free_extent_buffer(cur);
392 break;
393 }
394 search_start = tmp->start;
395 last_block = tmp->start;
396 *last_ret = search_start;
397 if (parent_level == 1)
398 btrfs_clear_buffer_defrag(tmp);
399 free_extent_buffer(tmp);
400 }
401 if (parent->map_token) {
402 unmap_extent_buffer(parent, parent->map_token,
403 KM_USER1);
404 parent->map_token = NULL;
405 }
406 return err;
407 }
408 #endif
409
410 /*
411 * The leaf data grows from end-to-front in the node.
412 * this returns the address of the start of the last item,
413 * which is the stop of the leaf data stack
414 */
415 static inline unsigned int leaf_data_end(struct btrfs_root *root,
416 struct extent_buffer *leaf)
417 {
418 u32 nr = btrfs_header_nritems(leaf);
419 if (nr == 0)
420 return BTRFS_LEAF_DATA_SIZE(root);
421 return btrfs_item_offset_nr(leaf, nr - 1);
422 }
423
424 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
425 int level)
426 {
427 struct extent_buffer *parent = NULL;
428 struct extent_buffer *node = path->nodes[level];
429 struct btrfs_disk_key parent_key;
430 struct btrfs_disk_key node_key;
431 int parent_slot;
432 int slot;
433 struct btrfs_key cpukey;
434 u32 nritems = btrfs_header_nritems(node);
435
436 if (path->nodes[level + 1])
437 parent = path->nodes[level + 1];
438
439 slot = path->slots[level];
440 BUG_ON(nritems == 0);
441 if (parent) {
442 parent_slot = path->slots[level + 1];
443 btrfs_node_key(parent, &parent_key, parent_slot);
444 btrfs_node_key(node, &node_key, 0);
445 BUG_ON(memcmp(&parent_key, &node_key,
446 sizeof(struct btrfs_disk_key)));
447 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
448 btrfs_header_bytenr(node));
449 }
450 BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
451 if (slot != 0) {
452 btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
453 btrfs_node_key(node, &node_key, slot);
454 BUG_ON(btrfs_comp_keys(&node_key, &cpukey) <= 0);
455 }
456 if (slot < nritems - 1) {
457 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
458 btrfs_node_key(node, &node_key, slot);
459 BUG_ON(btrfs_comp_keys(&node_key, &cpukey) >= 0);
460 }
461 return 0;
462 }
463
464 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
465 int level)
466 {
467 struct extent_buffer *leaf = path->nodes[level];
468 struct extent_buffer *parent = NULL;
469 int parent_slot;
470 struct btrfs_key cpukey;
471 struct btrfs_disk_key parent_key;
472 struct btrfs_disk_key leaf_key;
473 int slot = path->slots[0];
474
475 u32 nritems = btrfs_header_nritems(leaf);
476
477 if (path->nodes[level + 1])
478 parent = path->nodes[level + 1];
479
480 if (nritems == 0)
481 return 0;
482
483 if (parent) {
484 parent_slot = path->slots[level + 1];
485 btrfs_node_key(parent, &parent_key, parent_slot);
486 btrfs_item_key(leaf, &leaf_key, 0);
487
488 BUG_ON(memcmp(&parent_key, &leaf_key,
489 sizeof(struct btrfs_disk_key)));
490 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
491 btrfs_header_bytenr(leaf));
492 }
493 #if 0
494 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
495 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
496 btrfs_item_key(leaf, &leaf_key, i);
497 if (comp_keys(&leaf_key, &cpukey) >= 0) {
498 btrfs_print_leaf(root, leaf);
499 printk("slot %d offset bad key\n", i);
500 BUG_ON(1);
501 }
502 if (btrfs_item_offset_nr(leaf, i) !=
503 btrfs_item_end_nr(leaf, i + 1)) {
504 btrfs_print_leaf(root, leaf);
505 printk("slot %d offset bad\n", i);
506 BUG_ON(1);
507 }
508 if (i == 0) {
509 if (btrfs_item_offset_nr(leaf, i) +
510 btrfs_item_size_nr(leaf, i) !=
511 BTRFS_LEAF_DATA_SIZE(root)) {
512 btrfs_print_leaf(root, leaf);
513 printk("slot %d first offset bad\n", i);
514 BUG_ON(1);
515 }
516 }
517 }
518 if (nritems > 0) {
519 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
520 btrfs_print_leaf(root, leaf);
521 printk("slot %d bad size \n", nritems - 1);
522 BUG_ON(1);
523 }
524 }
525 #endif
526 if (slot != 0 && slot < nritems - 1) {
527 btrfs_item_key(leaf, &leaf_key, slot);
528 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
529 if (btrfs_comp_keys(&leaf_key, &cpukey) <= 0) {
530 btrfs_print_leaf(root, leaf);
531 printk("slot %d offset bad key\n", slot);
532 BUG_ON(1);
533 }
534 if (btrfs_item_offset_nr(leaf, slot - 1) !=
535 btrfs_item_end_nr(leaf, slot)) {
536 btrfs_print_leaf(root, leaf);
537 printk("slot %d offset bad\n", slot);
538 BUG_ON(1);
539 }
540 }
541 if (slot < nritems - 1) {
542 btrfs_item_key(leaf, &leaf_key, slot);
543 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
544 BUG_ON(btrfs_comp_keys(&leaf_key, &cpukey) >= 0);
545 if (btrfs_item_offset_nr(leaf, slot) !=
546 btrfs_item_end_nr(leaf, slot + 1)) {
547 btrfs_print_leaf(root, leaf);
548 printk("slot %d offset bad\n", slot);
549 BUG_ON(1);
550 }
551 }
552 BUG_ON(btrfs_item_offset_nr(leaf, 0) +
553 btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
554 return 0;
555 }
556
557 static int noinline check_block(struct btrfs_root *root,
558 struct btrfs_path *path, int level)
559 {
560 return 0;
561 #if 0
562 struct extent_buffer *buf = path->nodes[level];
563
564 if (memcmp_extent_buffer(buf, root->fs_info->fsid,
565 (unsigned long)btrfs_header_fsid(buf),
566 BTRFS_FSID_SIZE)) {
567 printk("warning bad block %Lu\n", buf->start);
568 return 1;
569 }
570 #endif
571 if (level == 0)
572 return check_leaf(root, path, level);
573 return check_node(root, path, level);
574 }
575
576 /*
577 * search for key in the extent_buffer. The items start at offset p,
578 * and they are item_size apart. There are 'max' items in p.
579 *
580 * the slot in the array is returned via slot, and it points to
581 * the place where you would insert key if it is not found in
582 * the array.
583 *
584 * slot may point to max if the key is bigger than all of the keys
585 */
586 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
587 int item_size, struct btrfs_key *key,
588 int max, int *slot)
589 {
590 int low = 0;
591 int high = max;
592 int mid;
593 int ret;
594 unsigned long offset;
595 struct btrfs_disk_key *tmp;
596
597 while(low < high) {
598 mid = (low + high) / 2;
599 offset = p + mid * item_size;
600
601 tmp = (struct btrfs_disk_key *)(eb->data + offset);
602 ret = btrfs_comp_keys(tmp, key);
603
604 if (ret < 0)
605 low = mid + 1;
606 else if (ret > 0)
607 high = mid;
608 else {
609 *slot = mid;
610 return 0;
611 }
612 }
613 *slot = low;
614 return 1;
615 }
616
617 /*
618 * simple bin_search frontend that does the right thing for
619 * leaves vs nodes
620 */
621 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
622 int level, int *slot)
623 {
624 if (level == 0) {
625 return generic_bin_search(eb,
626 offsetof(struct btrfs_leaf, items),
627 sizeof(struct btrfs_item),
628 key, btrfs_header_nritems(eb),
629 slot);
630 } else {
631 return generic_bin_search(eb,
632 offsetof(struct btrfs_node, ptrs),
633 sizeof(struct btrfs_key_ptr),
634 key, btrfs_header_nritems(eb),
635 slot);
636 }
637 return -1;
638 }
639
640 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
641 struct extent_buffer *parent, int slot)
642 {
643 if (slot < 0)
644 return NULL;
645 if (slot >= btrfs_header_nritems(parent))
646 return NULL;
647 return read_tree_block(root, btrfs_node_blockptr(parent, slot),
648 btrfs_level_size(root, btrfs_header_level(parent) - 1));
649 }
650
651 static int balance_level(struct btrfs_trans_handle *trans,
652 struct btrfs_root *root,
653 struct btrfs_path *path, int level)
654 {
655 struct extent_buffer *right = NULL;
656 struct extent_buffer *mid;
657 struct extent_buffer *left = NULL;
658 struct extent_buffer *parent = NULL;
659 int ret = 0;
660 int wret;
661 int pslot;
662 int orig_slot = path->slots[level];
663 int err_on_enospc = 0;
664 u64 orig_ptr;
665
666 if (level == 0)
667 return 0;
668
669 mid = path->nodes[level];
670 WARN_ON(btrfs_header_generation(mid) != trans->transid);
671
672 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
673
674 if (level < BTRFS_MAX_LEVEL - 1)
675 parent = path->nodes[level + 1];
676 pslot = path->slots[level + 1];
677
678 /*
679 * deal with the case where there is only one pointer in the root
680 * by promoting the node below to a root
681 */
682 if (!parent) {
683 struct extent_buffer *child;
684
685 if (btrfs_header_nritems(mid) != 1)
686 return 0;
687
688 /* promote the child to a root */
689 child = read_node_slot(root, mid, 0);
690 BUG_ON(!child);
691 root->node = child;
692 path->nodes[level] = NULL;
693 clean_tree_block(trans, root, mid);
694 wait_on_tree_block_writeback(root, mid);
695 /* once for the path */
696 free_extent_buffer(mid);
697 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
698 root->root_key.objectid,
699 btrfs_header_generation(mid), 0, 0, 1);
700 /* once for the root ptr */
701 free_extent_buffer(mid);
702 return ret;
703 }
704 if (btrfs_header_nritems(mid) >
705 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
706 return 0;
707
708 if (btrfs_header_nritems(mid) < 2)
709 err_on_enospc = 1;
710
711 left = read_node_slot(root, parent, pslot - 1);
712 if (left) {
713 wret = btrfs_cow_block(trans, root, left,
714 parent, pslot - 1, &left);
715 if (wret) {
716 ret = wret;
717 goto enospc;
718 }
719 }
720 right = read_node_slot(root, parent, pslot + 1);
721 if (right) {
722 wret = btrfs_cow_block(trans, root, right,
723 parent, pslot + 1, &right);
724 if (wret) {
725 ret = wret;
726 goto enospc;
727 }
728 }
729
730 /* first, try to make some room in the middle buffer */
731 if (left) {
732 orig_slot += btrfs_header_nritems(left);
733 wret = push_node_left(trans, root, left, mid);
734 if (wret < 0)
735 ret = wret;
736 if (btrfs_header_nritems(mid) < 2)
737 err_on_enospc = 1;
738 }
739
740 /*
741 * then try to empty the right most buffer into the middle
742 */
743 if (right) {
744 wret = push_node_left(trans, root, mid, right);
745 if (wret < 0 && wret != -ENOSPC)
746 ret = wret;
747 if (btrfs_header_nritems(right) == 0) {
748 u64 bytenr = right->start;
749 u64 generation = btrfs_header_generation(parent);
750 u32 blocksize = right->len;
751
752 clean_tree_block(trans, root, right);
753 wait_on_tree_block_writeback(root, right);
754 free_extent_buffer(right);
755 right = NULL;
756 wret = del_ptr(trans, root, path, level + 1, pslot +
757 1);
758 if (wret)
759 ret = wret;
760 wret = btrfs_free_extent(trans, root, bytenr,
761 blocksize,
762 btrfs_header_owner(parent),
763 generation, 0, 0, 1);
764 if (wret)
765 ret = wret;
766 } else {
767 struct btrfs_disk_key right_key;
768 btrfs_node_key(right, &right_key, 0);
769 btrfs_set_node_key(parent, &right_key, pslot + 1);
770 btrfs_mark_buffer_dirty(parent);
771 }
772 }
773 if (btrfs_header_nritems(mid) == 1) {
774 /*
775 * we're not allowed to leave a node with one item in the
776 * tree during a delete. A deletion from lower in the tree
777 * could try to delete the only pointer in this node.
778 * So, pull some keys from the left.
779 * There has to be a left pointer at this point because
780 * otherwise we would have pulled some pointers from the
781 * right
782 */
783 BUG_ON(!left);
784 wret = balance_node_right(trans, root, mid, left);
785 if (wret < 0) {
786 ret = wret;
787 goto enospc;
788 }
789 BUG_ON(wret == 1);
790 }
791 if (btrfs_header_nritems(mid) == 0) {
792 /* we've managed to empty the middle node, drop it */
793 u64 root_gen = btrfs_header_generation(parent);
794 u64 bytenr = mid->start;
795 u32 blocksize = mid->len;
796 clean_tree_block(trans, root, mid);
797 wait_on_tree_block_writeback(root, mid);
798 free_extent_buffer(mid);
799 mid = NULL;
800 wret = del_ptr(trans, root, path, level + 1, pslot);
801 if (wret)
802 ret = wret;
803 wret = btrfs_free_extent(trans, root, bytenr, blocksize,
804 btrfs_header_owner(parent),
805 root_gen, 0, 0, 1);
806 if (wret)
807 ret = wret;
808 } else {
809 /* update the parent key to reflect our changes */
810 struct btrfs_disk_key mid_key;
811 btrfs_node_key(mid, &mid_key, 0);
812 btrfs_set_node_key(parent, &mid_key, pslot);
813 btrfs_mark_buffer_dirty(parent);
814 }
815
816 /* update the path */
817 if (left) {
818 if (btrfs_header_nritems(left) > orig_slot) {
819 extent_buffer_get(left);
820 path->nodes[level] = left;
821 path->slots[level + 1] -= 1;
822 path->slots[level] = orig_slot;
823 if (mid)
824 free_extent_buffer(mid);
825 } else {
826 orig_slot -= btrfs_header_nritems(left);
827 path->slots[level] = orig_slot;
828 }
829 }
830 /* double check we haven't messed things up */
831 check_block(root, path, level);
832 if (orig_ptr !=
833 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
834 BUG();
835 enospc:
836 if (right)
837 free_extent_buffer(right);
838 if (left)
839 free_extent_buffer(left);
840 return ret;
841 }
842
843 /* returns zero if the push worked, non-zero otherwise */
844 static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
845 struct btrfs_root *root,
846 struct btrfs_path *path, int level)
847 {
848 struct extent_buffer *right = NULL;
849 struct extent_buffer *mid;
850 struct extent_buffer *left = NULL;
851 struct extent_buffer *parent = NULL;
852 int ret = 0;
853 int wret;
854 int pslot;
855 int orig_slot = path->slots[level];
856 u64 orig_ptr;
857
858 if (level == 0)
859 return 1;
860
861 mid = path->nodes[level];
862 WARN_ON(btrfs_header_generation(mid) != trans->transid);
863 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
864
865 if (level < BTRFS_MAX_LEVEL - 1)
866 parent = path->nodes[level + 1];
867 pslot = path->slots[level + 1];
868
869 if (!parent)
870 return 1;
871
872 left = read_node_slot(root, parent, pslot - 1);
873
874 /* first, try to make some room in the middle buffer */
875 if (left) {
876 u32 left_nr;
877 left_nr = btrfs_header_nritems(left);
878 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
879 wret = 1;
880 } else {
881 ret = btrfs_cow_block(trans, root, left, parent,
882 pslot - 1, &left);
883 if (ret)
884 wret = 1;
885 else {
886 wret = push_node_left(trans, root,
887 left, mid);
888 }
889 }
890 if (wret < 0)
891 ret = wret;
892 if (wret == 0) {
893 struct btrfs_disk_key disk_key;
894 orig_slot += left_nr;
895 btrfs_node_key(mid, &disk_key, 0);
896 btrfs_set_node_key(parent, &disk_key, pslot);
897 btrfs_mark_buffer_dirty(parent);
898 if (btrfs_header_nritems(left) > orig_slot) {
899 path->nodes[level] = left;
900 path->slots[level + 1] -= 1;
901 path->slots[level] = orig_slot;
902 free_extent_buffer(mid);
903 } else {
904 orig_slot -=
905 btrfs_header_nritems(left);
906 path->slots[level] = orig_slot;
907 free_extent_buffer(left);
908 }
909 return 0;
910 }
911 free_extent_buffer(left);
912 }
913 right= read_node_slot(root, parent, pslot + 1);
914
915 /*
916 * then try to empty the right most buffer into the middle
917 */
918 if (right) {
919 u32 right_nr;
920 right_nr = btrfs_header_nritems(right);
921 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
922 wret = 1;
923 } else {
924 ret = btrfs_cow_block(trans, root, right,
925 parent, pslot + 1,
926 &right);
927 if (ret)
928 wret = 1;
929 else {
930 wret = balance_node_right(trans, root,
931 right, mid);
932 }
933 }
934 if (wret < 0)
935 ret = wret;
936 if (wret == 0) {
937 struct btrfs_disk_key disk_key;
938
939 btrfs_node_key(right, &disk_key, 0);
940 btrfs_set_node_key(parent, &disk_key, pslot + 1);
941 btrfs_mark_buffer_dirty(parent);
942
943 if (btrfs_header_nritems(mid) <= orig_slot) {
944 path->nodes[level] = right;
945 path->slots[level + 1] += 1;
946 path->slots[level] = orig_slot -
947 btrfs_header_nritems(mid);
948 free_extent_buffer(mid);
949 } else {
950 free_extent_buffer(right);
951 }
952 return 0;
953 }
954 free_extent_buffer(right);
955 }
956 return 1;
957 }
958
959 /*
960 * readahead one full node of leaves
961 */
962 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
963 int level, int slot, u64 objectid)
964 {
965 struct extent_buffer *node;
966 struct btrfs_disk_key disk_key;
967 u32 nritems;
968 u64 search;
969 u64 lowest_read;
970 u64 highest_read;
971 u64 nread = 0;
972 int direction = path->reada;
973 struct extent_buffer *eb;
974 u32 nr;
975 u32 blocksize;
976 u32 nscan = 0;
977
978 if (level != 1)
979 return;
980
981 if (!path->nodes[level])
982 return;
983
984 node = path->nodes[level];
985 search = btrfs_node_blockptr(node, slot);
986 blocksize = btrfs_level_size(root, level - 1);
987 eb = btrfs_find_tree_block(root, search, blocksize);
988 if (eb) {
989 free_extent_buffer(eb);
990 return;
991 }
992
993 highest_read = search;
994 lowest_read = search;
995
996 nritems = btrfs_header_nritems(node);
997 nr = slot;
998 while(1) {
999 if (direction < 0) {
1000 if (nr == 0)
1001 break;
1002 nr--;
1003 } else if (direction > 0) {
1004 nr++;
1005 if (nr >= nritems)
1006 break;
1007 }
1008 if (path->reada < 0 && objectid) {
1009 btrfs_node_key(node, &disk_key, nr);
1010 if (btrfs_disk_key_objectid(&disk_key) != objectid)
1011 break;
1012 }
1013 search = btrfs_node_blockptr(node, nr);
1014 if ((search >= lowest_read && search <= highest_read) ||
1015 (search < lowest_read && lowest_read - search <= 32768) ||
1016 (search > highest_read && search - highest_read <= 32768)) {
1017 readahead_tree_block(root, search, blocksize);
1018 nread += blocksize;
1019 }
1020 nscan++;
1021 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
1022 break;
1023 if(nread > (1024 * 1024) || nscan > 128)
1024 break;
1025
1026 if (search < lowest_read)
1027 lowest_read = search;
1028 if (search > highest_read)
1029 highest_read = search;
1030 }
1031 }
1032
1033 /*
1034 * look for key in the tree. path is filled in with nodes along the way
1035 * if key is found, we return zero and you can find the item in the leaf
1036 * level of the path (level 0)
1037 *
1038 * If the key isn't found, the path points to the slot where it should
1039 * be inserted, and 1 is returned. If there are other errors during the
1040 * search a negative error number is returned.
1041 *
1042 * if ins_len > 0, nodes and leaves will be split as we walk down the
1043 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
1044 * possible)
1045 */
1046 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
1047 *root, struct btrfs_key *key, struct btrfs_path *p, int
1048 ins_len, int cow)
1049 {
1050 struct extent_buffer *b;
1051 u64 bytenr;
1052 u64 ptr_gen;
1053 int slot;
1054 int ret;
1055 int level;
1056 int should_reada = p->reada;
1057 u8 lowest_level = 0;
1058
1059 lowest_level = p->lowest_level;
1060 WARN_ON(lowest_level && ins_len);
1061 WARN_ON(p->nodes[0] != NULL);
1062 /*
1063 WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
1064 */
1065 again:
1066 b = root->node;
1067 extent_buffer_get(b);
1068 while (b) {
1069 level = btrfs_header_level(b);
1070 if (cow) {
1071 int wret;
1072 wret = btrfs_cow_block(trans, root, b,
1073 p->nodes[level + 1],
1074 p->slots[level + 1],
1075 &b);
1076 if (wret) {
1077 free_extent_buffer(b);
1078 return wret;
1079 }
1080 }
1081 BUG_ON(!cow && ins_len);
1082 if (level != btrfs_header_level(b))
1083 WARN_ON(1);
1084 level = btrfs_header_level(b);
1085 p->nodes[level] = b;
1086 ret = check_block(root, p, level);
1087 if (ret)
1088 return -1;
1089 ret = bin_search(b, key, level, &slot);
1090 if (level != 0) {
1091 if (ret && slot > 0)
1092 slot -= 1;
1093 p->slots[level] = slot;
1094 if (ins_len > 0 && btrfs_header_nritems(b) >=
1095 BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1096 int sret = split_node(trans, root, p, level);
1097 BUG_ON(sret > 0);
1098 if (sret)
1099 return sret;
1100 b = p->nodes[level];
1101 slot = p->slots[level];
1102 } else if (ins_len < 0) {
1103 int sret = balance_level(trans, root, p,
1104 level);
1105 if (sret)
1106 return sret;
1107 b = p->nodes[level];
1108 if (!b) {
1109 btrfs_release_path(NULL, p);
1110 goto again;
1111 }
1112 slot = p->slots[level];
1113 BUG_ON(btrfs_header_nritems(b) == 1);
1114 }
1115 /* this is only true while dropping a snapshot */
1116 if (level == lowest_level)
1117 break;
1118 bytenr = btrfs_node_blockptr(b, slot);
1119 ptr_gen = btrfs_node_ptr_generation(b, slot);
1120 if (should_reada)
1121 reada_for_search(root, p, level, slot,
1122 key->objectid);
1123 b = read_tree_block(root, bytenr,
1124 btrfs_level_size(root, level - 1));
1125 if (ptr_gen != btrfs_header_generation(b)) {
1126 printk("block %llu bad gen wanted %llu "
1127 "found %llu\n",
1128 (unsigned long long)b->start,
1129 (unsigned long long)ptr_gen,
1130 (unsigned long long)btrfs_header_generation(b));
1131 }
1132 } else {
1133 p->slots[level] = slot;
1134 if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1135 sizeof(struct btrfs_item) + ins_len) {
1136 int sret = split_leaf(trans, root, key,
1137 p, ins_len, ret == 0);
1138 BUG_ON(sret > 0);
1139 if (sret)
1140 return sret;
1141 }
1142 return ret;
1143 }
1144 }
1145 return 1;
1146 }
1147
1148 /*
1149 * adjust the pointers going up the tree, starting at level
1150 * making sure the right key of each node is points to 'key'.
1151 * This is used after shifting pointers to the left, so it stops
1152 * fixing up pointers when a given leaf/node is not in slot 0 of the
1153 * higher levels
1154 *
1155 * If this fails to write a tree block, it returns -1, but continues
1156 * fixing up the blocks in ram so the tree is consistent.
1157 */
1158 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1159 struct btrfs_root *root, struct btrfs_path *path,
1160 struct btrfs_disk_key *key, int level)
1161 {
1162 int i;
1163 int ret = 0;
1164 struct extent_buffer *t;
1165
1166 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1167 int tslot = path->slots[i];
1168 if (!path->nodes[i])
1169 break;
1170 t = path->nodes[i];
1171 btrfs_set_node_key(t, key, tslot);
1172 btrfs_mark_buffer_dirty(path->nodes[i]);
1173 if (tslot != 0)
1174 break;
1175 }
1176 return ret;
1177 }
1178
1179 /*
1180 * try to push data from one node into the next node left in the
1181 * tree.
1182 *
1183 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1184 * error, and > 0 if there was no room in the left hand block.
1185 */
1186 static int push_node_left(struct btrfs_trans_handle *trans,
1187 struct btrfs_root *root, struct extent_buffer *dst,
1188 struct extent_buffer *src)
1189 {
1190 int push_items = 0;
1191 int src_nritems;
1192 int dst_nritems;
1193 int ret = 0;
1194
1195 src_nritems = btrfs_header_nritems(src);
1196 dst_nritems = btrfs_header_nritems(dst);
1197 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1198 WARN_ON(btrfs_header_generation(src) != trans->transid);
1199 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1200
1201 if (push_items <= 0) {
1202 return 1;
1203 }
1204
1205 if (src_nritems < push_items)
1206 push_items = src_nritems;
1207
1208 copy_extent_buffer(dst, src,
1209 btrfs_node_key_ptr_offset(dst_nritems),
1210 btrfs_node_key_ptr_offset(0),
1211 push_items * sizeof(struct btrfs_key_ptr));
1212
1213 if (push_items < src_nritems) {
1214 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1215 btrfs_node_key_ptr_offset(push_items),
1216 (src_nritems - push_items) *
1217 sizeof(struct btrfs_key_ptr));
1218 }
1219 btrfs_set_header_nritems(src, src_nritems - push_items);
1220 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1221 btrfs_mark_buffer_dirty(src);
1222 btrfs_mark_buffer_dirty(dst);
1223 return ret;
1224 }
1225
1226 /*
1227 * try to push data from one node into the next node right in the
1228 * tree.
1229 *
1230 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1231 * error, and > 0 if there was no room in the right hand block.
1232 *
1233 * this will only push up to 1/2 the contents of the left node over
1234 */
1235 static int balance_node_right(struct btrfs_trans_handle *trans,
1236 struct btrfs_root *root,
1237 struct extent_buffer *dst,
1238 struct extent_buffer *src)
1239 {
1240 int push_items = 0;
1241 int max_push;
1242 int src_nritems;
1243 int dst_nritems;
1244 int ret = 0;
1245
1246 WARN_ON(btrfs_header_generation(src) != trans->transid);
1247 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1248
1249 src_nritems = btrfs_header_nritems(src);
1250 dst_nritems = btrfs_header_nritems(dst);
1251 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1252 if (push_items <= 0)
1253 return 1;
1254
1255 max_push = src_nritems / 2 + 1;
1256 /* don't try to empty the node */
1257 if (max_push >= src_nritems)
1258 return 1;
1259
1260 if (max_push < push_items)
1261 push_items = max_push;
1262
1263 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1264 btrfs_node_key_ptr_offset(0),
1265 (dst_nritems) *
1266 sizeof(struct btrfs_key_ptr));
1267
1268 copy_extent_buffer(dst, src,
1269 btrfs_node_key_ptr_offset(0),
1270 btrfs_node_key_ptr_offset(src_nritems - push_items),
1271 push_items * sizeof(struct btrfs_key_ptr));
1272
1273 btrfs_set_header_nritems(src, src_nritems - push_items);
1274 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1275
1276 btrfs_mark_buffer_dirty(src);
1277 btrfs_mark_buffer_dirty(dst);
1278 return ret;
1279 }
1280
1281 /*
1282 * helper function to insert a new root level in the tree.
1283 * A new node is allocated, and a single item is inserted to
1284 * point to the existing root
1285 *
1286 * returns zero on success or < 0 on failure.
1287 */
1288 static int noinline insert_new_root(struct btrfs_trans_handle *trans,
1289 struct btrfs_root *root,
1290 struct btrfs_path *path, int level)
1291 {
1292 u64 root_gen;
1293 u64 lower_gen;
1294 struct extent_buffer *lower;
1295 struct extent_buffer *c;
1296 struct btrfs_disk_key lower_key;
1297
1298 BUG_ON(path->nodes[level]);
1299 BUG_ON(path->nodes[level-1] != root->node);
1300
1301 if (root->ref_cows)
1302 root_gen = trans->transid;
1303 else
1304 root_gen = 0;
1305
1306 lower = path->nodes[level-1];
1307 if (level == 1)
1308 btrfs_item_key(lower, &lower_key, 0);
1309 else
1310 btrfs_node_key(lower, &lower_key, 0);
1311
1312 c = __btrfs_alloc_free_block(trans, root, root->nodesize,
1313 root->root_key.objectid,
1314 root_gen, lower_key.objectid, level,
1315 root->node->start, 0);
1316 if (IS_ERR(c))
1317 return PTR_ERR(c);
1318 memset_extent_buffer(c, 0, 0, root->nodesize);
1319 btrfs_set_header_nritems(c, 1);
1320 btrfs_set_header_level(c, level);
1321 btrfs_set_header_bytenr(c, c->start);
1322 btrfs_set_header_generation(c, trans->transid);
1323 btrfs_set_header_owner(c, root->root_key.objectid);
1324
1325 write_extent_buffer(c, root->fs_info->fsid,
1326 (unsigned long)btrfs_header_fsid(c),
1327 BTRFS_FSID_SIZE);
1328 btrfs_set_node_key(c, &lower_key, 0);
1329 btrfs_set_node_blockptr(c, 0, lower->start);
1330 lower_gen = btrfs_header_generation(lower);
1331 WARN_ON(lower_gen == 0);
1332
1333 btrfs_set_node_ptr_generation(c, 0, lower_gen);
1334
1335 btrfs_mark_buffer_dirty(c);
1336
1337 /* the super has an extra ref to root->node */
1338 free_extent_buffer(root->node);
1339 root->node = c;
1340 extent_buffer_get(c);
1341 path->nodes[level] = c;
1342 path->slots[level] = 0;
1343
1344 if (root->ref_cows && lower_gen != trans->transid) {
1345 struct btrfs_path *back_path = btrfs_alloc_path();
1346 int ret;
1347 ret = btrfs_insert_extent_backref(trans,
1348 root->fs_info->extent_root,
1349 path, lower->start,
1350 root->root_key.objectid,
1351 trans->transid, 0, 0);
1352 BUG_ON(ret);
1353 btrfs_free_path(back_path);
1354 }
1355 return 0;
1356 }
1357
1358 /*
1359 * worker function to insert a single pointer in a node.
1360 * the node should have enough room for the pointer already
1361 *
1362 * slot and level indicate where you want the key to go, and
1363 * blocknr is the block the key points to.
1364 *
1365 * returns zero on success and < 0 on any error
1366 */
1367 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1368 *root, struct btrfs_path *path, struct btrfs_disk_key
1369 *key, u64 bytenr, int slot, int level)
1370 {
1371 struct extent_buffer *lower;
1372 int nritems;
1373
1374 BUG_ON(!path->nodes[level]);
1375 lower = path->nodes[level];
1376 nritems = btrfs_header_nritems(lower);
1377 if (slot > nritems)
1378 BUG();
1379 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1380 BUG();
1381 if (slot != nritems) {
1382 memmove_extent_buffer(lower,
1383 btrfs_node_key_ptr_offset(slot + 1),
1384 btrfs_node_key_ptr_offset(slot),
1385 (nritems - slot) * sizeof(struct btrfs_key_ptr));
1386 }
1387 btrfs_set_node_key(lower, key, slot);
1388 btrfs_set_node_blockptr(lower, slot, bytenr);
1389 WARN_ON(trans->transid == 0);
1390 btrfs_set_node_ptr_generation(lower, slot, trans->transid);
1391 btrfs_set_header_nritems(lower, nritems + 1);
1392 btrfs_mark_buffer_dirty(lower);
1393 return 0;
1394 }
1395
1396 /*
1397 * split the node at the specified level in path in two.
1398 * The path is corrected to point to the appropriate node after the split
1399 *
1400 * Before splitting this tries to make some room in the node by pushing
1401 * left and right, if either one works, it returns right away.
1402 *
1403 * returns 0 on success and < 0 on failure
1404 */
1405 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1406 *root, struct btrfs_path *path, int level)
1407 {
1408 u64 root_gen;
1409 struct extent_buffer *c;
1410 struct extent_buffer *split;
1411 struct btrfs_disk_key disk_key;
1412 int mid;
1413 int ret;
1414 int wret;
1415 u32 c_nritems;
1416
1417 c = path->nodes[level];
1418 WARN_ON(btrfs_header_generation(c) != trans->transid);
1419 if (c == root->node) {
1420 /* trying to split the root, lets make a new one */
1421 ret = insert_new_root(trans, root, path, level + 1);
1422 if (ret)
1423 return ret;
1424 } else {
1425 ret = push_nodes_for_insert(trans, root, path, level);
1426 c = path->nodes[level];
1427 if (!ret && btrfs_header_nritems(c) <
1428 BTRFS_NODEPTRS_PER_BLOCK(root) - 1)
1429 return 0;
1430 if (ret < 0)
1431 return ret;
1432 }
1433
1434 c_nritems = btrfs_header_nritems(c);
1435 if (root->ref_cows)
1436 root_gen = trans->transid;
1437 else
1438 root_gen = 0;
1439
1440 btrfs_node_key(c, &disk_key, 0);
1441 split = __btrfs_alloc_free_block(trans, root, root->nodesize,
1442 root->root_key.objectid,
1443 root_gen,
1444 btrfs_disk_key_objectid(&disk_key),
1445 level, c->start, 0);
1446 if (IS_ERR(split))
1447 return PTR_ERR(split);
1448
1449 btrfs_set_header_flags(split, btrfs_header_flags(c));
1450 btrfs_set_header_level(split, btrfs_header_level(c));
1451 btrfs_set_header_bytenr(split, split->start);
1452 btrfs_set_header_generation(split, trans->transid);
1453 btrfs_set_header_owner(split, root->root_key.objectid);
1454 write_extent_buffer(split, root->fs_info->fsid,
1455 (unsigned long)btrfs_header_fsid(split),
1456 BTRFS_FSID_SIZE);
1457
1458 mid = (c_nritems + 1) / 2;
1459
1460 copy_extent_buffer(split, c,
1461 btrfs_node_key_ptr_offset(0),
1462 btrfs_node_key_ptr_offset(mid),
1463 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1464 btrfs_set_header_nritems(split, c_nritems - mid);
1465 btrfs_set_header_nritems(c, mid);
1466 ret = 0;
1467
1468 btrfs_mark_buffer_dirty(c);
1469 btrfs_mark_buffer_dirty(split);
1470
1471 btrfs_node_key(split, &disk_key, 0);
1472 wret = insert_ptr(trans, root, path, &disk_key, split->start,
1473 path->slots[level + 1] + 1,
1474 level + 1);
1475 if (wret)
1476 ret = wret;
1477
1478 if (path->slots[level] >= mid) {
1479 path->slots[level] -= mid;
1480 free_extent_buffer(c);
1481 path->nodes[level] = split;
1482 path->slots[level + 1] += 1;
1483 } else {
1484 free_extent_buffer(split);
1485 }
1486 return ret;
1487 }
1488
1489 /*
1490 * how many bytes are required to store the items in a leaf. start
1491 * and nr indicate which items in the leaf to check. This totals up the
1492 * space used both by the item structs and the item data
1493 */
1494 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1495 {
1496 int data_len;
1497 int nritems = btrfs_header_nritems(l);
1498 int end = min(nritems, start + nr) - 1;
1499
1500 if (!nr)
1501 return 0;
1502 data_len = btrfs_item_end_nr(l, start);
1503 data_len = data_len - btrfs_item_offset_nr(l, end);
1504 data_len += sizeof(struct btrfs_item) * nr;
1505 WARN_ON(data_len < 0);
1506 return data_len;
1507 }
1508
1509 /*
1510 * The space between the end of the leaf items and
1511 * the start of the leaf data. IOW, how much room
1512 * the leaf has left for both items and data
1513 */
1514 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1515 {
1516 int nritems = btrfs_header_nritems(leaf);
1517 int ret;
1518 ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1519 if (ret < 0) {
1520 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1521 ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
1522 leaf_space_used(leaf, 0, nritems), nritems);
1523 }
1524 return ret;
1525 }
1526
1527 /*
1528 * push some data in the path leaf to the right, trying to free up at
1529 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1530 *
1531 * returns 1 if the push failed because the other node didn't have enough
1532 * room, 0 if everything worked out and < 0 if there were major errors.
1533 */
1534 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1535 *root, struct btrfs_path *path, int data_size,
1536 int empty)
1537 {
1538 struct extent_buffer *left = path->nodes[0];
1539 struct extent_buffer *right;
1540 struct extent_buffer *upper;
1541 struct btrfs_disk_key disk_key;
1542 int slot;
1543 u32 i;
1544 int free_space;
1545 int push_space = 0;
1546 int push_items = 0;
1547 struct btrfs_item *item;
1548 u32 left_nritems;
1549 u32 nr;
1550 u32 right_nritems;
1551 u32 data_end;
1552 u32 this_item_size;
1553 int ret;
1554
1555 slot = path->slots[1];
1556 if (!path->nodes[1]) {
1557 return 1;
1558 }
1559 upper = path->nodes[1];
1560 if (slot >= btrfs_header_nritems(upper) - 1)
1561 return 1;
1562
1563 right = read_tree_block(root, btrfs_node_blockptr(upper, slot + 1),
1564 root->leafsize);
1565 free_space = btrfs_leaf_free_space(root, right);
1566 if (free_space < data_size + sizeof(struct btrfs_item)) {
1567 free_extent_buffer(right);
1568 return 1;
1569 }
1570
1571 /* cow and double check */
1572 ret = btrfs_cow_block(trans, root, right, upper,
1573 slot + 1, &right);
1574 if (ret) {
1575 free_extent_buffer(right);
1576 return 1;
1577 }
1578 free_space = btrfs_leaf_free_space(root, right);
1579 if (free_space < data_size + sizeof(struct btrfs_item)) {
1580 free_extent_buffer(right);
1581 return 1;
1582 }
1583
1584 left_nritems = btrfs_header_nritems(left);
1585 if (left_nritems == 0) {
1586 free_extent_buffer(right);
1587 return 1;
1588 }
1589
1590 if (empty)
1591 nr = 0;
1592 else
1593 nr = 1;
1594
1595 i = left_nritems - 1;
1596 while (i >= nr) {
1597 item = btrfs_item_nr(left, i);
1598
1599 if (path->slots[0] == i)
1600 push_space += data_size + sizeof(*item);
1601
1602 this_item_size = btrfs_item_size(left, item);
1603 if (this_item_size + sizeof(*item) + push_space > free_space)
1604 break;
1605 push_items++;
1606 push_space += this_item_size + sizeof(*item);
1607 if (i == 0)
1608 break;
1609 i--;
1610 }
1611
1612 if (push_items == 0) {
1613 free_extent_buffer(right);
1614 return 1;
1615 }
1616
1617 if (!empty && push_items == left_nritems)
1618 WARN_ON(1);
1619
1620 /* push left to right */
1621 right_nritems = btrfs_header_nritems(right);
1622
1623 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1624 push_space -= leaf_data_end(root, left);
1625
1626 /* make room in the right data area */
1627 data_end = leaf_data_end(root, right);
1628 memmove_extent_buffer(right,
1629 btrfs_leaf_data(right) + data_end - push_space,
1630 btrfs_leaf_data(right) + data_end,
1631 BTRFS_LEAF_DATA_SIZE(root) - data_end);
1632
1633 /* copy from the left data area */
1634 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1635 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1636 btrfs_leaf_data(left) + leaf_data_end(root, left),
1637 push_space);
1638
1639 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1640 btrfs_item_nr_offset(0),
1641 right_nritems * sizeof(struct btrfs_item));
1642
1643 /* copy the items from left to right */
1644 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1645 btrfs_item_nr_offset(left_nritems - push_items),
1646 push_items * sizeof(struct btrfs_item));
1647
1648 /* update the item pointers */
1649 right_nritems += push_items;
1650 btrfs_set_header_nritems(right, right_nritems);
1651 push_space = BTRFS_LEAF_DATA_SIZE(root);
1652 for (i = 0; i < right_nritems; i++) {
1653 item = btrfs_item_nr(right, i);
1654 push_space -= btrfs_item_size(right, item);
1655 btrfs_set_item_offset(right, item, push_space);
1656 }
1657
1658 left_nritems -= push_items;
1659 btrfs_set_header_nritems(left, left_nritems);
1660
1661 if (left_nritems)
1662 btrfs_mark_buffer_dirty(left);
1663 btrfs_mark_buffer_dirty(right);
1664
1665 btrfs_item_key(right, &disk_key, 0);
1666 btrfs_set_node_key(upper, &disk_key, slot + 1);
1667 btrfs_mark_buffer_dirty(upper);
1668
1669 /* then fixup the leaf pointer in the path */
1670 if (path->slots[0] >= left_nritems) {
1671 path->slots[0] -= left_nritems;
1672 free_extent_buffer(path->nodes[0]);
1673 path->nodes[0] = right;
1674 path->slots[1] += 1;
1675 } else {
1676 free_extent_buffer(right);
1677 }
1678 return 0;
1679 }
1680 /*
1681 * push some data in the path leaf to the left, trying to free up at
1682 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1683 */
1684 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1685 *root, struct btrfs_path *path, int data_size,
1686 int empty)
1687 {
1688 struct btrfs_disk_key disk_key;
1689 struct extent_buffer *right = path->nodes[0];
1690 struct extent_buffer *left;
1691 int slot;
1692 int i;
1693 int free_space;
1694 int push_space = 0;
1695 int push_items = 0;
1696 struct btrfs_item *item;
1697 u32 old_left_nritems;
1698 u32 right_nritems;
1699 u32 nr;
1700 int ret = 0;
1701 int wret;
1702 u32 this_item_size;
1703 u32 old_left_item_size;
1704
1705 slot = path->slots[1];
1706 if (slot == 0)
1707 return 1;
1708 if (!path->nodes[1])
1709 return 1;
1710
1711 right_nritems = btrfs_header_nritems(right);
1712 if (right_nritems == 0) {
1713 return 1;
1714 }
1715
1716 left = read_tree_block(root, btrfs_node_blockptr(path->nodes[1],
1717 slot - 1), root->leafsize);
1718 free_space = btrfs_leaf_free_space(root, left);
1719 if (free_space < data_size + sizeof(struct btrfs_item)) {
1720 free_extent_buffer(left);
1721 return 1;
1722 }
1723
1724 /* cow and double check */
1725 ret = btrfs_cow_block(trans, root, left,
1726 path->nodes[1], slot - 1, &left);
1727 if (ret) {
1728 /* we hit -ENOSPC, but it isn't fatal here */
1729 free_extent_buffer(left);
1730 return 1;
1731 }
1732
1733 free_space = btrfs_leaf_free_space(root, left);
1734 if (free_space < data_size + sizeof(struct btrfs_item)) {
1735 free_extent_buffer(left);
1736 return 1;
1737 }
1738
1739 if (empty)
1740 nr = right_nritems;
1741 else
1742 nr = right_nritems - 1;
1743
1744 for (i = 0; i < nr; i++) {
1745 item = btrfs_item_nr(right, i);
1746
1747 if (path->slots[0] == i)
1748 push_space += data_size + sizeof(*item);
1749
1750 this_item_size = btrfs_item_size(right, item);
1751 if (this_item_size + sizeof(*item) + push_space > free_space)
1752 break;
1753
1754 push_items++;
1755 push_space += this_item_size + sizeof(*item);
1756 }
1757
1758 if (push_items == 0) {
1759 free_extent_buffer(left);
1760 return 1;
1761 }
1762 if (!empty && push_items == btrfs_header_nritems(right))
1763 WARN_ON(1);
1764
1765 /* push data from right to left */
1766 copy_extent_buffer(left, right,
1767 btrfs_item_nr_offset(btrfs_header_nritems(left)),
1768 btrfs_item_nr_offset(0),
1769 push_items * sizeof(struct btrfs_item));
1770
1771 push_space = BTRFS_LEAF_DATA_SIZE(root) -
1772 btrfs_item_offset_nr(right, push_items -1);
1773
1774 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
1775 leaf_data_end(root, left) - push_space,
1776 btrfs_leaf_data(right) +
1777 btrfs_item_offset_nr(right, push_items - 1),
1778 push_space);
1779 old_left_nritems = btrfs_header_nritems(left);
1780 BUG_ON(old_left_nritems < 0);
1781
1782 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
1783 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1784 u32 ioff;
1785
1786 item = btrfs_item_nr(left, i);
1787 ioff = btrfs_item_offset(left, item);
1788 btrfs_set_item_offset(left, item,
1789 ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
1790 }
1791 btrfs_set_header_nritems(left, old_left_nritems + push_items);
1792
1793 /* fixup right node */
1794 if (push_items > right_nritems) {
1795 printk("push items %d nr %u\n", push_items, right_nritems);
1796 WARN_ON(1);
1797 }
1798
1799 if (push_items < right_nritems) {
1800 push_space = btrfs_item_offset_nr(right, push_items - 1) -
1801 leaf_data_end(root, right);
1802 memmove_extent_buffer(right, btrfs_leaf_data(right) +
1803 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1804 btrfs_leaf_data(right) +
1805 leaf_data_end(root, right), push_space);
1806
1807 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
1808 btrfs_item_nr_offset(push_items),
1809 (btrfs_header_nritems(right) - push_items) *
1810 sizeof(struct btrfs_item));
1811 }
1812 right_nritems -= push_items;
1813 btrfs_set_header_nritems(right, right_nritems);
1814 push_space = BTRFS_LEAF_DATA_SIZE(root);
1815 for (i = 0; i < right_nritems; i++) {
1816 item = btrfs_item_nr(right, i);
1817 push_space = push_space - btrfs_item_size(right, item);
1818 btrfs_set_item_offset(right, item, push_space);
1819 }
1820
1821 btrfs_mark_buffer_dirty(left);
1822 if (right_nritems)
1823 btrfs_mark_buffer_dirty(right);
1824
1825 btrfs_item_key(right, &disk_key, 0);
1826 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1827 if (wret)
1828 ret = wret;
1829
1830 /* then fixup the leaf pointer in the path */
1831 if (path->slots[0] < push_items) {
1832 path->slots[0] += old_left_nritems;
1833 free_extent_buffer(path->nodes[0]);
1834 path->nodes[0] = left;
1835 path->slots[1] -= 1;
1836 } else {
1837 free_extent_buffer(left);
1838 path->slots[0] -= push_items;
1839 }
1840 BUG_ON(path->slots[0] < 0);
1841 return ret;
1842 }
1843
1844 /*
1845 * split the path's leaf in two, making sure there is at least data_size
1846 * available for the resulting leaf level of the path.
1847 *
1848 * returns 0 if all went well and < 0 on failure.
1849 */
1850 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1851 *root, struct btrfs_key *ins_key,
1852 struct btrfs_path *path, int data_size, int extend)
1853 {
1854 u64 root_gen;
1855 struct extent_buffer *l;
1856 u32 nritems;
1857 int mid;
1858 int slot;
1859 struct extent_buffer *right;
1860 int space_needed = data_size + sizeof(struct btrfs_item);
1861 int data_copy_size;
1862 int rt_data_off;
1863 int i;
1864 int ret = 0;
1865 int wret;
1866 int double_split;
1867 int num_doubles = 0;
1868 struct btrfs_disk_key disk_key;
1869
1870 if (extend)
1871 space_needed = data_size;
1872
1873 if (root->ref_cows)
1874 root_gen = trans->transid;
1875 else
1876 root_gen = 0;
1877
1878 /* first try to make some room by pushing left and right */
1879 if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
1880 wret = push_leaf_right(trans, root, path, data_size, 0);
1881 if (wret < 0) {
1882 return wret;
1883 }
1884 if (wret) {
1885 wret = push_leaf_left(trans, root, path, data_size, 0);
1886 if (wret < 0)
1887 return wret;
1888 }
1889 l = path->nodes[0];
1890
1891 /* did the pushes work? */
1892 if (btrfs_leaf_free_space(root, l) >= space_needed)
1893 return 0;
1894 }
1895
1896 if (!path->nodes[1]) {
1897 ret = insert_new_root(trans, root, path, 1);
1898 if (ret)
1899 return ret;
1900 }
1901 again:
1902 double_split = 0;
1903 l = path->nodes[0];
1904 slot = path->slots[0];
1905 nritems = btrfs_header_nritems(l);
1906 mid = (nritems + 1)/ 2;
1907
1908 btrfs_item_key(l, &disk_key, 0);
1909
1910 right = __btrfs_alloc_free_block(trans, root, root->leafsize,
1911 root->root_key.objectid,
1912 root_gen, disk_key.objectid, 0,
1913 l->start, 0);
1914 if (IS_ERR(right))
1915 return PTR_ERR(right);
1916
1917 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
1918 btrfs_set_header_bytenr(right, right->start);
1919 btrfs_set_header_generation(right, trans->transid);
1920 btrfs_set_header_owner(right, root->root_key.objectid);
1921 btrfs_set_header_level(right, 0);
1922 write_extent_buffer(right, root->fs_info->fsid,
1923 (unsigned long)btrfs_header_fsid(right),
1924 BTRFS_FSID_SIZE);
1925 if (mid <= slot) {
1926 if (nritems == 1 ||
1927 leaf_space_used(l, mid, nritems - mid) + space_needed >
1928 BTRFS_LEAF_DATA_SIZE(root)) {
1929 if (slot >= nritems) {
1930 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1931 btrfs_set_header_nritems(right, 0);
1932 wret = insert_ptr(trans, root, path,
1933 &disk_key, right->start,
1934 path->slots[1] + 1, 1);
1935 if (wret)
1936 ret = wret;
1937 free_extent_buffer(path->nodes[0]);
1938 path->nodes[0] = right;
1939 path->slots[0] = 0;
1940 path->slots[1] += 1;
1941 return ret;
1942 }
1943 mid = slot;
1944 if (mid != nritems &&
1945 leaf_space_used(l, mid, nritems - mid) +
1946 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
1947 double_split = 1;
1948 }
1949 }
1950 } else {
1951 if (leaf_space_used(l, 0, mid + 1) + space_needed >
1952 BTRFS_LEAF_DATA_SIZE(root)) {
1953 if (!extend && slot == 0) {
1954 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1955 btrfs_set_header_nritems(right, 0);
1956 wret = insert_ptr(trans, root, path,
1957 &disk_key,
1958 right->start,
1959 path->slots[1], 1);
1960 if (wret)
1961 ret = wret;
1962 free_extent_buffer(path->nodes[0]);
1963 path->nodes[0] = right;
1964 path->slots[0] = 0;
1965 if (path->slots[1] == 0) {
1966 wret = fixup_low_keys(trans, root,
1967 path, &disk_key, 1);
1968 if (wret)
1969 ret = wret;
1970 }
1971 return ret;
1972 } else if (extend && slot == 0) {
1973 mid = 1;
1974 } else {
1975 mid = slot;
1976 if (mid != nritems &&
1977 leaf_space_used(l, mid, nritems - mid) +
1978 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
1979 double_split = 1;
1980 }
1981 }
1982 }
1983 }
1984 nritems = nritems - mid;
1985 btrfs_set_header_nritems(right, nritems);
1986 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
1987
1988 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
1989 btrfs_item_nr_offset(mid),
1990 nritems * sizeof(struct btrfs_item));
1991
1992 copy_extent_buffer(right, l,
1993 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
1994 data_copy_size, btrfs_leaf_data(l) +
1995 leaf_data_end(root, l), data_copy_size);
1996
1997 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
1998 btrfs_item_end_nr(l, mid);
1999
2000 for (i = 0; i < nritems; i++) {
2001 struct btrfs_item *item = btrfs_item_nr(right, i);
2002 u32 ioff = btrfs_item_offset(right, item);
2003 btrfs_set_item_offset(right, item, ioff + rt_data_off);
2004 }
2005
2006 btrfs_set_header_nritems(l, mid);
2007 ret = 0;
2008 btrfs_item_key(right, &disk_key, 0);
2009 wret = insert_ptr(trans, root, path, &disk_key, right->start,
2010 path->slots[1] + 1, 1);
2011 if (wret)
2012 ret = wret;
2013
2014 btrfs_mark_buffer_dirty(right);
2015 btrfs_mark_buffer_dirty(l);
2016 BUG_ON(path->slots[0] != slot);
2017
2018 if (mid <= slot) {
2019 free_extent_buffer(path->nodes[0]);
2020 path->nodes[0] = right;
2021 path->slots[0] -= mid;
2022 path->slots[1] += 1;
2023 } else
2024 free_extent_buffer(right);
2025
2026 BUG_ON(path->slots[0] < 0);
2027
2028 if (double_split) {
2029 BUG_ON(num_doubles != 0);
2030 num_doubles++;
2031 goto again;
2032 }
2033 return ret;
2034 }
2035
2036 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
2037 struct btrfs_root *root,
2038 struct btrfs_path *path,
2039 u32 new_size, int from_end)
2040 {
2041 int ret = 0;
2042 int slot;
2043 int slot_orig;
2044 struct extent_buffer *leaf;
2045 struct btrfs_item *item;
2046 u32 nritems;
2047 unsigned int data_end;
2048 unsigned int old_data_start;
2049 unsigned int old_size;
2050 unsigned int size_diff;
2051 int i;
2052
2053 slot_orig = path->slots[0];
2054 leaf = path->nodes[0];
2055 slot = path->slots[0];
2056
2057 old_size = btrfs_item_size_nr(leaf, slot);
2058 if (old_size == new_size)
2059 return 0;
2060
2061 nritems = btrfs_header_nritems(leaf);
2062 data_end = leaf_data_end(root, leaf);
2063
2064 old_data_start = btrfs_item_offset_nr(leaf, slot);
2065
2066 size_diff = old_size - new_size;
2067
2068 BUG_ON(slot < 0);
2069 BUG_ON(slot >= nritems);
2070
2071 /*
2072 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2073 */
2074 /* first correct the data pointers */
2075 for (i = slot; i < nritems; i++) {
2076 u32 ioff;
2077 item = btrfs_item_nr(leaf, i);
2078 ioff = btrfs_item_offset(leaf, item);
2079 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2080 }
2081
2082 /* shift the data */
2083 if (from_end) {
2084 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2085 data_end + size_diff, btrfs_leaf_data(leaf) +
2086 data_end, old_data_start + new_size - data_end);
2087 } else {
2088 struct btrfs_disk_key disk_key;
2089 u64 offset;
2090
2091 btrfs_item_key(leaf, &disk_key, slot);
2092
2093 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2094 unsigned long ptr;
2095 struct btrfs_file_extent_item *fi;
2096
2097 fi = btrfs_item_ptr(leaf, slot,
2098 struct btrfs_file_extent_item);
2099 fi = (struct btrfs_file_extent_item *)(
2100 (unsigned long)fi - size_diff);
2101
2102 if (btrfs_file_extent_type(leaf, fi) ==
2103 BTRFS_FILE_EXTENT_INLINE) {
2104 ptr = btrfs_item_ptr_offset(leaf, slot);
2105 memmove_extent_buffer(leaf, ptr,
2106 (unsigned long)fi,
2107 offsetof(struct btrfs_file_extent_item,
2108 disk_bytenr));
2109 }
2110 }
2111
2112 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2113 data_end + size_diff, btrfs_leaf_data(leaf) +
2114 data_end, old_data_start - data_end);
2115
2116 offset = btrfs_disk_key_offset(&disk_key);
2117 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2118 btrfs_set_item_key(leaf, &disk_key, slot);
2119 if (slot == 0)
2120 fixup_low_keys(trans, root, path, &disk_key, 1);
2121 }
2122
2123 item = btrfs_item_nr(leaf, slot);
2124 btrfs_set_item_size(leaf, item, new_size);
2125 btrfs_mark_buffer_dirty(leaf);
2126
2127 ret = 0;
2128 if (btrfs_leaf_free_space(root, leaf) < 0) {
2129 btrfs_print_leaf(root, leaf);
2130 BUG();
2131 }
2132 return ret;
2133 }
2134
2135 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2136 struct btrfs_root *root, struct btrfs_path *path,
2137 u32 data_size)
2138 {
2139 int ret = 0;
2140 int slot;
2141 int slot_orig;
2142 struct extent_buffer *leaf;
2143 struct btrfs_item *item;
2144 u32 nritems;
2145 unsigned int data_end;
2146 unsigned int old_data;
2147 unsigned int old_size;
2148 int i;
2149
2150 slot_orig = path->slots[0];
2151 leaf = path->nodes[0];
2152
2153 nritems = btrfs_header_nritems(leaf);
2154 data_end = leaf_data_end(root, leaf);
2155
2156 if (btrfs_leaf_free_space(root, leaf) < data_size) {
2157 btrfs_print_leaf(root, leaf);
2158 BUG();
2159 }
2160 slot = path->slots[0];
2161 old_data = btrfs_item_end_nr(leaf, slot);
2162
2163 BUG_ON(slot < 0);
2164 if (slot >= nritems) {
2165 btrfs_print_leaf(root, leaf);
2166 printk("slot %d too large, nritems %d\n", slot, nritems);
2167 BUG_ON(1);
2168 }
2169
2170 /*
2171 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2172 */
2173 /* first correct the data pointers */
2174 for (i = slot; i < nritems; i++) {
2175 u32 ioff;
2176 item = btrfs_item_nr(leaf, i);
2177 ioff = btrfs_item_offset(leaf, item);
2178 btrfs_set_item_offset(leaf, item, ioff - data_size);
2179 }
2180
2181 /* shift the data */
2182 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2183 data_end - data_size, btrfs_leaf_data(leaf) +
2184 data_end, old_data - data_end);
2185
2186 data_end = old_data;
2187 old_size = btrfs_item_size_nr(leaf, slot);
2188 item = btrfs_item_nr(leaf, slot);
2189 btrfs_set_item_size(leaf, item, old_size + data_size);
2190 btrfs_mark_buffer_dirty(leaf);
2191
2192 ret = 0;
2193 if (btrfs_leaf_free_space(root, leaf) < 0) {
2194 btrfs_print_leaf(root, leaf);
2195 BUG();
2196 }
2197 return ret;
2198 }
2199
2200 /*
2201 * Given a key and some data, insert an item into the tree.
2202 * This does all the path init required, making room in the tree if needed.
2203 */
2204 int btrfs_insert_empty_item(struct btrfs_trans_handle *trans,
2205 struct btrfs_root *root,
2206 struct btrfs_path *path,
2207 struct btrfs_key *cpu_key, u32 data_size)
2208 {
2209 struct extent_buffer *leaf;
2210 struct btrfs_item *item;
2211 int ret = 0;
2212 int slot;
2213 int slot_orig;
2214 u32 nritems;
2215 unsigned int data_end;
2216 struct btrfs_disk_key disk_key;
2217
2218 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2219
2220 /* create a root if there isn't one */
2221 if (!root->node)
2222 BUG();
2223
2224 ret = btrfs_search_slot(trans, root, cpu_key, path, data_size, 1);
2225 if (ret == 0) {
2226 return -EEXIST;
2227 }
2228 if (ret < 0)
2229 goto out;
2230
2231 slot_orig = path->slots[0];
2232 leaf = path->nodes[0];
2233
2234 nritems = btrfs_header_nritems(leaf);
2235 data_end = leaf_data_end(root, leaf);
2236
2237 if (btrfs_leaf_free_space(root, leaf) <
2238 sizeof(struct btrfs_item) + data_size) {
2239 btrfs_print_leaf(root, leaf);
2240 printk("not enough freespace need %u have %d\n",
2241 data_size, btrfs_leaf_free_space(root, leaf));
2242 BUG();
2243 }
2244
2245 slot = path->slots[0];
2246 BUG_ON(slot < 0);
2247
2248 if (slot != nritems) {
2249 int i;
2250 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2251
2252 if (old_data < data_end) {
2253 btrfs_print_leaf(root, leaf);
2254 printk("slot %d old_data %d data_end %d\n",
2255 slot, old_data, data_end);
2256 BUG_ON(1);
2257 }
2258 /*
2259 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2260 */
2261 /* first correct the data pointers */
2262 for (i = slot; i < nritems; i++) {
2263 u32 ioff;
2264
2265 item = btrfs_item_nr(leaf, i);
2266 ioff = btrfs_item_offset(leaf, item);
2267 btrfs_set_item_offset(leaf, item, ioff - data_size);
2268 }
2269
2270 /* shift the items */
2271 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1),
2272 btrfs_item_nr_offset(slot),
2273 (nritems - slot) * sizeof(struct btrfs_item));
2274
2275 /* shift the data */
2276 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2277 data_end - data_size, btrfs_leaf_data(leaf) +
2278 data_end, old_data - data_end);
2279 data_end = old_data;
2280 }
2281
2282 /* setup the item for the new data */
2283 btrfs_set_item_key(leaf, &disk_key, slot);
2284 item = btrfs_item_nr(leaf, slot);
2285 btrfs_set_item_offset(leaf, item, data_end - data_size);
2286 btrfs_set_item_size(leaf, item, data_size);
2287 btrfs_set_header_nritems(leaf, nritems + 1);
2288 btrfs_mark_buffer_dirty(leaf);
2289
2290 ret = 0;
2291 if (slot == 0)
2292 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2293
2294 if (btrfs_leaf_free_space(root, leaf) < 0) {
2295 btrfs_print_leaf(root, leaf);
2296 BUG();
2297 }
2298 out:
2299 return ret;
2300 }
2301
2302 /*
2303 * Given a key and some data, insert an item into the tree.
2304 * This does all the path init required, making room in the tree if needed.
2305 */
2306 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2307 *root, struct btrfs_key *cpu_key, void *data, u32
2308 data_size)
2309 {
2310 int ret = 0;
2311 struct btrfs_path *path;
2312 struct extent_buffer *leaf;
2313 unsigned long ptr;
2314
2315 path = btrfs_alloc_path();
2316 BUG_ON(!path);
2317 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2318 if (!ret) {
2319 leaf = path->nodes[0];
2320 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2321 write_extent_buffer(leaf, data, ptr, data_size);
2322 btrfs_mark_buffer_dirty(leaf);
2323 }
2324 btrfs_free_path(path);
2325 return ret;
2326 }
2327
2328 /*
2329 * delete the pointer from a given node.
2330 *
2331 * If the delete empties a node, the node is removed from the tree,
2332 * continuing all the way the root if required. The root is converted into
2333 * a leaf if all the nodes are emptied.
2334 */
2335 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2336 struct btrfs_path *path, int level, int slot)
2337 {
2338 struct extent_buffer *parent = path->nodes[level];
2339 u32 nritems;
2340 int ret = 0;
2341 int wret;
2342
2343 nritems = btrfs_header_nritems(parent);
2344 if (slot != nritems -1) {
2345 memmove_extent_buffer(parent,
2346 btrfs_node_key_ptr_offset(slot),
2347 btrfs_node_key_ptr_offset(slot + 1),
2348 sizeof(struct btrfs_key_ptr) *
2349 (nritems - slot - 1));
2350 }
2351 nritems--;
2352 btrfs_set_header_nritems(parent, nritems);
2353 if (nritems == 0 && parent == root->node) {
2354 BUG_ON(btrfs_header_level(root->node) != 1);
2355 /* just turn the root into a leaf and break */
2356 btrfs_set_header_level(root->node, 0);
2357 } else if (slot == 0) {
2358 struct btrfs_disk_key disk_key;
2359
2360 btrfs_node_key(parent, &disk_key, 0);
2361 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2362 if (wret)
2363 ret = wret;
2364 }
2365 btrfs_mark_buffer_dirty(parent);
2366 return ret;
2367 }
2368
2369 /*
2370 * delete the item at the leaf level in path. If that empties
2371 * the leaf, remove it from the tree
2372 */
2373 int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2374 struct btrfs_path *path)
2375 {
2376 int slot;
2377 struct extent_buffer *leaf;
2378 struct btrfs_item *item;
2379 int doff;
2380 int dsize;
2381 int ret = 0;
2382 int wret;
2383 u32 nritems;
2384
2385 leaf = path->nodes[0];
2386 slot = path->slots[0];
2387 doff = btrfs_item_offset_nr(leaf, slot);
2388 dsize = btrfs_item_size_nr(leaf, slot);
2389 nritems = btrfs_header_nritems(leaf);
2390
2391 if (slot != nritems - 1) {
2392 int i;
2393 int data_end = leaf_data_end(root, leaf);
2394
2395 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2396 data_end + dsize,
2397 btrfs_leaf_data(leaf) + data_end,
2398 doff - data_end);
2399
2400 for (i = slot + 1; i < nritems; i++) {
2401 u32 ioff;
2402
2403 item = btrfs_item_nr(leaf, i);
2404 ioff = btrfs_item_offset(leaf, item);
2405 btrfs_set_item_offset(leaf, item, ioff + dsize);
2406 }
2407
2408 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2409 btrfs_item_nr_offset(slot + 1),
2410 sizeof(struct btrfs_item) *
2411 (nritems - slot - 1));
2412 }
2413 btrfs_set_header_nritems(leaf, nritems - 1);
2414 nritems--;
2415
2416 /* delete the leaf if we've emptied it */
2417 if (nritems == 0) {
2418 if (leaf == root->node) {
2419 btrfs_set_header_level(leaf, 0);
2420 } else {
2421 u64 root_gen = btrfs_header_generation(path->nodes[1]);
2422 clean_tree_block(trans, root, leaf);
2423 wait_on_tree_block_writeback(root, leaf);
2424 wret = del_ptr(trans, root, path, 1, path->slots[1]);
2425 if (wret)
2426 ret = wret;
2427 wret = btrfs_free_extent(trans, root,
2428 leaf->start, leaf->len,
2429 btrfs_header_owner(path->nodes[1]),
2430 root_gen, 0, 0, 1);
2431 if (wret)
2432 ret = wret;
2433 }
2434 } else {
2435 int used = leaf_space_used(leaf, 0, nritems);
2436 if (slot == 0) {
2437 struct btrfs_disk_key disk_key;
2438
2439 btrfs_item_key(leaf, &disk_key, 0);
2440 wret = fixup_low_keys(trans, root, path,
2441 &disk_key, 1);
2442 if (wret)
2443 ret = wret;
2444 }
2445
2446 /* delete the leaf if it is mostly empty */
2447 if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) {
2448 /* push_leaf_left fixes the path.
2449 * make sure the path still points to our leaf
2450 * for possible call to del_ptr below
2451 */
2452 slot = path->slots[1];
2453 extent_buffer_get(leaf);
2454
2455 wret = push_leaf_right(trans, root, path, 1, 1);
2456 if (wret < 0 && wret != -ENOSPC)
2457 ret = wret;
2458
2459 if (path->nodes[0] == leaf &&
2460 btrfs_header_nritems(leaf)) {
2461 wret = push_leaf_left(trans, root, path, 1, 1);
2462 if (wret < 0 && wret != -ENOSPC)
2463 ret = wret;
2464 }
2465
2466 if (btrfs_header_nritems(leaf) == 0) {
2467 u64 root_gen;
2468 u64 bytenr = leaf->start;
2469 u32 blocksize = leaf->len;
2470
2471 root_gen = btrfs_header_generation(
2472 path->nodes[1]);
2473
2474 clean_tree_block(trans, root, leaf);
2475 wait_on_tree_block_writeback(root, leaf);
2476
2477 wret = del_ptr(trans, root, path, 1, slot);
2478 if (wret)
2479 ret = wret;
2480
2481 free_extent_buffer(leaf);
2482 wret = btrfs_free_extent(trans, root, bytenr,
2483 blocksize,
2484 btrfs_header_owner(path->nodes[1]),
2485 root_gen, 0, 0, 1);
2486 if (wret)
2487 ret = wret;
2488 } else {
2489 btrfs_mark_buffer_dirty(leaf);
2490 free_extent_buffer(leaf);
2491 }
2492 } else {
2493 btrfs_mark_buffer_dirty(leaf);
2494 }
2495 }
2496 return ret;
2497 }
2498
2499 /*
2500 * walk up the tree as far as required to find the previous leaf.
2501 * returns 0 if it found something or 1 if there are no lesser leaves.
2502 * returns < 0 on io errors.
2503 */
2504 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
2505 {
2506 u64 bytenr;
2507 int slot;
2508 int level = 1;
2509 struct extent_buffer *c;
2510 struct extent_buffer *next = NULL;
2511
2512 while(level < BTRFS_MAX_LEVEL) {
2513 if (!path->nodes[level])
2514 return 1;
2515
2516 slot = path->slots[level];
2517 c = path->nodes[level];
2518 if (slot == 0) {
2519 level++;
2520 if (level == BTRFS_MAX_LEVEL)
2521 return 1;
2522 continue;
2523 }
2524 slot--;
2525
2526 bytenr = btrfs_node_blockptr(c, slot);
2527 if (next)
2528 free_extent_buffer(next);
2529
2530 next = read_tree_block(root, bytenr,
2531 btrfs_level_size(root, level - 1));
2532 break;
2533 }
2534 path->slots[level] = slot;
2535 while(1) {
2536 level--;
2537 c = path->nodes[level];
2538 free_extent_buffer(c);
2539 slot = btrfs_header_nritems(next);
2540 if (slot != 0)
2541 slot--;
2542 path->nodes[level] = next;
2543 path->slots[level] = slot;
2544 if (!level)
2545 break;
2546 next = read_tree_block(root, btrfs_node_blockptr(next, slot),
2547 btrfs_level_size(root, level - 1));
2548 }
2549 return 0;
2550 }
2551
2552 /*
2553 * walk up the tree as far as required to find the next leaf.
2554 * returns 0 if it found something or 1 if there are no greater leaves.
2555 * returns < 0 on io errors.
2556 */
2557 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2558 {
2559 int slot;
2560 int level = 1;
2561 u64 bytenr;
2562 struct extent_buffer *c;
2563 struct extent_buffer *next = NULL;
2564
2565 while(level < BTRFS_MAX_LEVEL) {
2566 if (!path->nodes[level])
2567 return 1;
2568
2569 slot = path->slots[level] + 1;
2570 c = path->nodes[level];
2571 if (slot >= btrfs_header_nritems(c)) {
2572 level++;
2573 if (level == BTRFS_MAX_LEVEL)
2574 return 1;
2575 continue;
2576 }
2577
2578 bytenr = btrfs_node_blockptr(c, slot);
2579 if (next)
2580 free_extent_buffer(next);
2581
2582 if (path->reada)
2583 reada_for_search(root, path, level, slot, 0);
2584
2585 next = read_tree_block(root, bytenr,
2586 btrfs_level_size(root, level -1));
2587 break;
2588 }
2589 path->slots[level] = slot;
2590 while(1) {
2591 level--;
2592 c = path->nodes[level];
2593 free_extent_buffer(c);
2594 path->nodes[level] = next;
2595 path->slots[level] = 0;
2596 if (!level)
2597 break;
2598 if (path->reada)
2599 reada_for_search(root, path, level, 0, 0);
2600 next = read_tree_block(root, btrfs_node_blockptr(next, 0),
2601 btrfs_level_size(root, level - 1));
2602 }
2603 return 0;
2604 }
Btrfs-progs-unstable mirror