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btrfs-progs: Fix printf format casting errors
[btrfs-progs-unstable/devel.git] / ctree.c
blob5e423754be8acd3cfe3b74ae2883d7029f50612e
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);
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 u32 nritems;
86 int ret = 0;
87 int level;
88 struct btrfs_key first_key;
89 struct btrfs_root *new_root;
90
91 new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
92 if (!new_root)
93 return -ENOMEM;
94
95 memcpy(new_root, root, sizeof(*new_root));
96 new_root->root_key.objectid = new_root_objectid;
97
98 WARN_ON(root->ref_cows && trans->transid !=
99 root->fs_info->running_transaction->transid);
100 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
101
102 level = btrfs_header_level(buf);
103 nritems = btrfs_header_nritems(buf);
104 if (nritems) {
105 if (level == 0)
106 btrfs_item_key_to_cpu(buf, &first_key, 0);
107 else
108 btrfs_node_key_to_cpu(buf, &first_key, 0);
109 } else {
110 first_key.objectid = 0;
111 }
112 cow = __btrfs_alloc_free_block(trans, new_root, buf->len,
113 new_root_objectid,
114 trans->transid, first_key.objectid,
115 level, buf->start, 0);
116 if (IS_ERR(cow)) {
117 kfree(new_root);
118 return PTR_ERR(cow);
119 }
120
121 copy_extent_buffer(cow, buf, 0, 0, cow->len);
122 btrfs_set_header_bytenr(cow, cow->start);
123 btrfs_set_header_generation(cow, trans->transid);
124 btrfs_set_header_owner(cow, new_root_objectid);
125 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
126
127 WARN_ON(btrfs_header_generation(buf) > trans->transid);
128 ret = btrfs_inc_ref(trans, new_root, buf);
129 kfree(new_root);
130
131 if (ret)
132 return ret;
133
134 btrfs_mark_buffer_dirty(cow);
135 *cow_ret = cow;
136 return 0;
137 }
138
139 int __btrfs_cow_block(struct btrfs_trans_handle *trans,
140 struct btrfs_root *root,
141 struct extent_buffer *buf,
142 struct extent_buffer *parent, int parent_slot,
143 struct extent_buffer **cow_ret,
144 u64 search_start, u64 empty_size)
145 {
146 u64 root_gen;
147 struct extent_buffer *cow;
148 u32 nritems;
149 int ret = 0;
150 int different_trans = 0;
151 int level;
152 struct btrfs_key first_key;
153
154 if (root->ref_cows) {
155 root_gen = trans->transid;
156 } else {
157 root_gen = 0;
158 }
159
160 WARN_ON(root->ref_cows && trans->transid !=
161 root->fs_info->running_transaction->transid);
162 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
163
164 level = btrfs_header_level(buf);
165 nritems = btrfs_header_nritems(buf);
166 if (nritems) {
167 if (level == 0)
168 btrfs_item_key_to_cpu(buf, &first_key, 0);
169 else
170 btrfs_node_key_to_cpu(buf, &first_key, 0);
171 } else {
172 first_key.objectid = 0;
173 }
174 cow = __btrfs_alloc_free_block(trans, root, buf->len,
175 root->root_key.objectid,
176 root_gen, first_key.objectid, level,
177 search_start, empty_size);
178 if (IS_ERR(cow))
179 return PTR_ERR(cow);
180
181 copy_extent_buffer(cow, buf, 0, 0, cow->len);
182 btrfs_set_header_bytenr(cow, cow->start);
183 btrfs_set_header_generation(cow, trans->transid);
184 btrfs_set_header_owner(cow, root->root_key.objectid);
185 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
186
187 WARN_ON(btrfs_header_generation(buf) > trans->transid);
188 if (btrfs_header_generation(buf) != trans->transid) {
189 different_trans = 1;
190 ret = btrfs_inc_ref(trans, root, buf);
191 if (ret)
192 return ret;
193 } else {
194 clean_tree_block(trans, root, buf);
195 }
196
197 if (buf == root->node) {
198 root_gen = btrfs_header_generation(buf);
199 root->node = cow;
200 extent_buffer_get(cow);
201 if (buf != root->commit_root) {
202 btrfs_free_extent(trans, root, buf->start,
203 buf->len, root->root_key.objectid,
204 root_gen, 0, 0, 1);
205 }
206 free_extent_buffer(buf);
207 add_root_to_dirty_list(root);
208 } else {
209 root_gen = btrfs_header_generation(parent);
210 btrfs_set_node_blockptr(parent, parent_slot,
211 cow->start);
212 WARN_ON(trans->transid == 0);
213 btrfs_set_node_ptr_generation(parent, parent_slot,
214 trans->transid);
215 btrfs_mark_buffer_dirty(parent);
216 WARN_ON(btrfs_header_generation(parent) != trans->transid);
217 btrfs_free_extent(trans, root, buf->start, buf->len,
218 btrfs_header_owner(parent), root_gen,
219 0, 0, 1);
220 }
221 free_extent_buffer(buf);
222 btrfs_mark_buffer_dirty(cow);
223 *cow_ret = cow;
224 return 0;
225 }
226
227 int btrfs_cow_block(struct btrfs_trans_handle *trans,
228 struct btrfs_root *root, struct extent_buffer *buf,
229 struct extent_buffer *parent, int parent_slot,
230 struct extent_buffer **cow_ret)
231 {
232 u64 search_start;
233 int ret;
234 /*
235 if (trans->transaction != root->fs_info->running_transaction) {
236 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
237 root->fs_info->running_transaction->transid);
238 WARN_ON(1);
239 }
240 */
241 if (trans->transid != root->fs_info->generation) {
242 printk(KERN_CRIT "trans %llu running %llu\n",
243 (unsigned long long)trans->transid,
244 (unsigned long long)root->fs_info->generation);
245 WARN_ON(1);
246 }
247 if (btrfs_header_generation(buf) == trans->transid) {
248 #if 0
249 &&
250 !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
251 #endif
252 *cow_ret = buf;
253 return 0;
254 }
255
256 search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
257 ret = __btrfs_cow_block(trans, root, buf, parent,
258 parent_slot, cow_ret, search_start, 0);
259 return ret;
260 }
261
262 /*
263 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
264 {
265 if (blocknr < other && other - (blocknr + blocksize) < 32768)
266 return 1;
267 if (blocknr > other && blocknr - (other + blocksize) < 32768)
268 return 1;
269 return 0;
270 }
271 */
272
273 /*
274 * compare two keys in a memcmp fashion
275 */
276 int btrfs_comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
277 {
278 struct btrfs_key k1;
279
280 btrfs_disk_key_to_cpu(&k1, disk);
281
282 if (k1.objectid > k2->objectid)
283 return 1;
284 if (k1.objectid < k2->objectid)
285 return -1;
286 if (k1.type > k2->type)
287 return 1;
288 if (k1.type < k2->type)
289 return -1;
290 if (k1.offset > k2->offset)
291 return 1;
292 if (k1.offset < k2->offset)
293 return -1;
294 return 0;
295 }
296
297
298 #if 0
299 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
300 struct btrfs_root *root, struct extent_buffer *parent,
301 int start_slot, int cache_only, u64 *last_ret,
302 struct btrfs_key *progress)
303 {
304 struct extent_buffer *cur;
305 struct extent_buffer *tmp;
306 u64 blocknr;
307 u64 search_start = *last_ret;
308 u64 last_block = 0;
309 u64 other;
310 u32 parent_nritems;
311 int end_slot;
312 int i;
313 int err = 0;
314 int parent_level;
315 int uptodate;
316 u32 blocksize;
317 int progress_passed = 0;
318 struct btrfs_disk_key disk_key;
319
320 parent_level = btrfs_header_level(parent);
321 if (cache_only && parent_level != 1)
322 return 0;
323
324 if (trans->transaction != root->fs_info->running_transaction) {
325 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
326 root->fs_info->running_transaction->transid);
327 WARN_ON(1);
328 }
329 if (trans->transid != root->fs_info->generation) {
330 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
331 root->fs_info->generation);
332 WARN_ON(1);
333 }
334
335 parent_nritems = btrfs_header_nritems(parent);
336 blocksize = btrfs_level_size(root, parent_level - 1);
337 end_slot = parent_nritems;
338
339 if (parent_nritems == 1)
340 return 0;
341
342 for (i = start_slot; i < end_slot; i++) {
343 int close = 1;
344
345 if (!parent->map_token) {
346 map_extent_buffer(parent,
347 btrfs_node_key_ptr_offset(i),
348 sizeof(struct btrfs_key_ptr),
349 &parent->map_token, &parent->kaddr,
350 &parent->map_start, &parent->map_len,
351 KM_USER1);
352 }
353 btrfs_node_key(parent, &disk_key, i);
354 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
355 continue;
356
357 progress_passed = 1;
358 blocknr = btrfs_node_blockptr(parent, i);
359 if (last_block == 0)
360 last_block = blocknr;
361
362 if (i > 0) {
363 other = btrfs_node_blockptr(parent, i - 1);
364 close = close_blocks(blocknr, other, blocksize);
365 }
366 if (close && i < end_slot - 2) {
367 other = btrfs_node_blockptr(parent, i + 1);
368 close = close_blocks(blocknr, other, blocksize);
369 }
370 if (close) {
371 last_block = blocknr;
372 continue;
373 }
374 if (parent->map_token) {
375 unmap_extent_buffer(parent, parent->map_token,
376 KM_USER1);
377 parent->map_token = NULL;
378 }
379
380 cur = btrfs_find_tree_block(root, blocknr, blocksize);
381 if (cur)
382 uptodate = btrfs_buffer_uptodate(cur);
383 else
384 uptodate = 0;
385 if (!cur || !uptodate) {
386 if (cache_only) {
387 free_extent_buffer(cur);
388 continue;
389 }
390 if (!cur) {
391 cur = read_tree_block(root, blocknr,
392 blocksize);
393 } else if (!uptodate) {
394 btrfs_read_buffer(cur);
395 }
396 }
397 if (search_start == 0)
398 search_start = last_block;
399
400 err = __btrfs_cow_block(trans, root, cur, parent, i,
401 &tmp, search_start,
402 min(16 * blocksize,
403 (end_slot - i) * blocksize));
404 if (err) {
405 free_extent_buffer(cur);
406 break;
407 }
408 search_start = tmp->start;
409 last_block = tmp->start;
410 *last_ret = search_start;
411 if (parent_level == 1)
412 btrfs_clear_buffer_defrag(tmp);
413 free_extent_buffer(tmp);
414 }
415 if (parent->map_token) {
416 unmap_extent_buffer(parent, parent->map_token,
417 KM_USER1);
418 parent->map_token = NULL;
419 }
420 return err;
421 }
422 #endif
423
424 /*
425 * The leaf data grows from end-to-front in the node.
426 * this returns the address of the start of the last item,
427 * which is the stop of the leaf data stack
428 */
429 static inline unsigned int leaf_data_end(struct btrfs_root *root,
430 struct extent_buffer *leaf)
431 {
432 u32 nr = btrfs_header_nritems(leaf);
433 if (nr == 0)
434 return BTRFS_LEAF_DATA_SIZE(root);
435 return btrfs_item_offset_nr(leaf, nr - 1);
436 }
437
438 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
439 int level)
440 {
441 struct extent_buffer *parent = NULL;
442 struct extent_buffer *node = path->nodes[level];
443 struct btrfs_disk_key parent_key;
444 struct btrfs_disk_key node_key;
445 int parent_slot;
446 int slot;
447 struct btrfs_key cpukey;
448 u32 nritems = btrfs_header_nritems(node);
449
450 if (path->nodes[level + 1])
451 parent = path->nodes[level + 1];
452
453 slot = path->slots[level];
454 BUG_ON(nritems == 0);
455 if (parent) {
456 parent_slot = path->slots[level + 1];
457 btrfs_node_key(parent, &parent_key, parent_slot);
458 btrfs_node_key(node, &node_key, 0);
459 BUG_ON(memcmp(&parent_key, &node_key,
460 sizeof(struct btrfs_disk_key)));
461 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
462 btrfs_header_bytenr(node));
463 }
464 BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
465 if (slot != 0) {
466 btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
467 btrfs_node_key(node, &node_key, slot);
468 BUG_ON(btrfs_comp_keys(&node_key, &cpukey) <= 0);
469 }
470 if (slot < nritems - 1) {
471 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
472 btrfs_node_key(node, &node_key, slot);
473 BUG_ON(btrfs_comp_keys(&node_key, &cpukey) >= 0);
474 }
475 return 0;
476 }
477
478 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
479 int level)
480 {
481 struct extent_buffer *leaf = path->nodes[level];
482 struct extent_buffer *parent = NULL;
483 int parent_slot;
484 struct btrfs_key cpukey;
485 struct btrfs_disk_key parent_key;
486 struct btrfs_disk_key leaf_key;
487 int slot = path->slots[0];
488
489 u32 nritems = btrfs_header_nritems(leaf);
490
491 if (path->nodes[level + 1])
492 parent = path->nodes[level + 1];
493
494 if (nritems == 0)
495 return 0;
496
497 if (parent) {
498 parent_slot = path->slots[level + 1];
499 btrfs_node_key(parent, &parent_key, parent_slot);
500 btrfs_item_key(leaf, &leaf_key, 0);
501
502 BUG_ON(memcmp(&parent_key, &leaf_key,
503 sizeof(struct btrfs_disk_key)));
504 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
505 btrfs_header_bytenr(leaf));
506 }
507 #if 0
508 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
509 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
510 btrfs_item_key(leaf, &leaf_key, i);
511 if (comp_keys(&leaf_key, &cpukey) >= 0) {
512 btrfs_print_leaf(root, leaf);
513 printk("slot %d offset bad key\n", i);
514 BUG_ON(1);
515 }
516 if (btrfs_item_offset_nr(leaf, i) !=
517 btrfs_item_end_nr(leaf, i + 1)) {
518 btrfs_print_leaf(root, leaf);
519 printk("slot %d offset bad\n", i);
520 BUG_ON(1);
521 }
522 if (i == 0) {
523 if (btrfs_item_offset_nr(leaf, i) +
524 btrfs_item_size_nr(leaf, i) !=
525 BTRFS_LEAF_DATA_SIZE(root)) {
526 btrfs_print_leaf(root, leaf);
527 printk("slot %d first offset bad\n", i);
528 BUG_ON(1);
529 }
530 }
531 }
532 if (nritems > 0) {
533 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
534 btrfs_print_leaf(root, leaf);
535 printk("slot %d bad size \n", nritems - 1);
536 BUG_ON(1);
537 }
538 }
539 #endif
540 if (slot != 0 && slot < nritems - 1) {
541 btrfs_item_key(leaf, &leaf_key, slot);
542 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
543 if (btrfs_comp_keys(&leaf_key, &cpukey) <= 0) {
544 btrfs_print_leaf(root, leaf);
545 printk("slot %d offset bad key\n", slot);
546 BUG_ON(1);
547 }
548 if (btrfs_item_offset_nr(leaf, slot - 1) !=
549 btrfs_item_end_nr(leaf, slot)) {
550 btrfs_print_leaf(root, leaf);
551 printk("slot %d offset bad\n", slot);
552 BUG_ON(1);
553 }
554 }
555 if (slot < nritems - 1) {
556 btrfs_item_key(leaf, &leaf_key, slot);
557 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
558 BUG_ON(btrfs_comp_keys(&leaf_key, &cpukey) >= 0);
559 if (btrfs_item_offset_nr(leaf, slot) !=
560 btrfs_item_end_nr(leaf, slot + 1)) {
561 btrfs_print_leaf(root, leaf);
562 printk("slot %d offset bad\n", slot);
563 BUG_ON(1);
564 }
565 }
566 BUG_ON(btrfs_item_offset_nr(leaf, 0) +
567 btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
568 return 0;
569 }
570
571 static int noinline check_block(struct btrfs_root *root,
572 struct btrfs_path *path, int level)
573 {
574 return 0;
575 #if 0
576 struct extent_buffer *buf = path->nodes[level];
577
578 if (memcmp_extent_buffer(buf, root->fs_info->fsid,
579 (unsigned long)btrfs_header_fsid(buf),
580 BTRFS_FSID_SIZE)) {
581 printk("warning bad block %Lu\n", buf->start);
582 return 1;
583 }
584 #endif
585 if (level == 0)
586 return check_leaf(root, path, level);
587 return check_node(root, path, level);
588 }
589
590 /*
591 * search for key in the extent_buffer. The items start at offset p,
592 * and they are item_size apart. There are 'max' items in p.
593 *
594 * the slot in the array is returned via slot, and it points to
595 * the place where you would insert key if it is not found in
596 * the array.
597 *
598 * slot may point to max if the key is bigger than all of the keys
599 */
600 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
601 int item_size, struct btrfs_key *key,
602 int max, int *slot)
603 {
604 int low = 0;
605 int high = max;
606 int mid;
607 int ret;
608 unsigned long offset;
609 struct btrfs_disk_key *tmp;
610
611 while(low < high) {
612 mid = (low + high) / 2;
613 offset = p + mid * item_size;
614
615 tmp = (struct btrfs_disk_key *)(eb->data + offset);
616 ret = btrfs_comp_keys(tmp, key);
617
618 if (ret < 0)
619 low = mid + 1;
620 else if (ret > 0)
621 high = mid;
622 else {
623 *slot = mid;
624 return 0;
625 }
626 }
627 *slot = low;
628 return 1;
629 }
630
631 /*
632 * simple bin_search frontend that does the right thing for
633 * leaves vs nodes
634 */
635 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
636 int level, int *slot)
637 {
638 if (level == 0) {
639 return generic_bin_search(eb,
640 offsetof(struct btrfs_leaf, items),
641 sizeof(struct btrfs_item),
642 key, btrfs_header_nritems(eb),
643 slot);
644 } else {
645 return generic_bin_search(eb,
646 offsetof(struct btrfs_node, ptrs),
647 sizeof(struct btrfs_key_ptr),
648 key, btrfs_header_nritems(eb),
649 slot);
650 }
651 return -1;
652 }
653
654 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
655 struct extent_buffer *parent, int slot)
656 {
657 if (slot < 0)
658 return NULL;
659 if (slot >= btrfs_header_nritems(parent))
660 return NULL;
661 return read_tree_block(root, btrfs_node_blockptr(parent, slot),
662 btrfs_level_size(root, btrfs_header_level(parent) - 1));
663 }
664
665 static int balance_level(struct btrfs_trans_handle *trans,
666 struct btrfs_root *root,
667 struct btrfs_path *path, int level)
668 {
669 struct extent_buffer *right = NULL;
670 struct extent_buffer *mid;
671 struct extent_buffer *left = NULL;
672 struct extent_buffer *parent = NULL;
673 int ret = 0;
674 int wret;
675 int pslot;
676 int orig_slot = path->slots[level];
677 int err_on_enospc = 0;
678 u64 orig_ptr;
679
680 if (level == 0)
681 return 0;
682
683 mid = path->nodes[level];
684 WARN_ON(btrfs_header_generation(mid) != trans->transid);
685
686 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
687
688 if (level < BTRFS_MAX_LEVEL - 1)
689 parent = path->nodes[level + 1];
690 pslot = path->slots[level + 1];
691
692 /*
693 * deal with the case where there is only one pointer in the root
694 * by promoting the node below to a root
695 */
696 if (!parent) {
697 struct extent_buffer *child;
698
699 if (btrfs_header_nritems(mid) != 1)
700 return 0;
701
702 /* promote the child to a root */
703 child = read_node_slot(root, mid, 0);
704 BUG_ON(!child);
705 ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
706 BUG_ON(ret);
707
708 root->node = child;
709 add_root_to_dirty_list(root);
710 path->nodes[level] = NULL;
711 clean_tree_block(trans, root, mid);
712 wait_on_tree_block_writeback(root, mid);
713 /* once for the path */
714 free_extent_buffer(mid);
715 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
716 root->root_key.objectid,
717 btrfs_header_generation(mid), 0, 0, 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);
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);
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,
780 btrfs_header_owner(parent),
781 generation, 0, 0, 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 BUG_ON(wret == 1);
808 }
809 if (btrfs_header_nritems(mid) == 0) {
810 /* we've managed to empty the middle node, drop it */
811 u64 root_gen = btrfs_header_generation(parent);
812 u64 bytenr = mid->start;
813 u32 blocksize = mid->len;
814 clean_tree_block(trans, root, mid);
815 wait_on_tree_block_writeback(root, mid);
816 free_extent_buffer(mid);
817 mid = NULL;
818 wret = del_ptr(trans, root, path, level + 1, pslot);
819 if (wret)
820 ret = wret;
821 wret = btrfs_free_extent(trans, root, bytenr, blocksize,
822 btrfs_header_owner(parent),
823 root_gen, 0, 0, 1);
824 if (wret)
825 ret = wret;
826 } else {
827 /* update the parent key to reflect our changes */
828 struct btrfs_disk_key mid_key;
829 btrfs_node_key(mid, &mid_key, 0);
830 btrfs_set_node_key(parent, &mid_key, pslot);
831 btrfs_mark_buffer_dirty(parent);
832 }
833
834 /* update the path */
835 if (left) {
836 if (btrfs_header_nritems(left) > orig_slot) {
837 extent_buffer_get(left);
838 path->nodes[level] = left;
839 path->slots[level + 1] -= 1;
840 path->slots[level] = orig_slot;
841 if (mid)
842 free_extent_buffer(mid);
843 } else {
844 orig_slot -= btrfs_header_nritems(left);
845 path->slots[level] = orig_slot;
846 }
847 }
848 /* double check we haven't messed things up */
849 check_block(root, path, level);
850 if (orig_ptr !=
851 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
852 BUG();
853 enospc:
854 if (right)
855 free_extent_buffer(right);
856 if (left)
857 free_extent_buffer(left);
858 return ret;
859 }
860
861 /* returns zero if the push worked, non-zero otherwise */
862 static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
863 struct btrfs_root *root,
864 struct btrfs_path *path, int level)
865 {
866 struct extent_buffer *right = NULL;
867 struct extent_buffer *mid;
868 struct extent_buffer *left = NULL;
869 struct extent_buffer *parent = NULL;
870 int ret = 0;
871 int wret;
872 int pslot;
873 int orig_slot = path->slots[level];
874 u64 orig_ptr;
875
876 if (level == 0)
877 return 1;
878
879 mid = path->nodes[level];
880 WARN_ON(btrfs_header_generation(mid) != trans->transid);
881 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
882
883 if (level < BTRFS_MAX_LEVEL - 1)
884 parent = path->nodes[level + 1];
885 pslot = path->slots[level + 1];
886
887 if (!parent)
888 return 1;
889
890 left = read_node_slot(root, parent, pslot - 1);
891
892 /* first, try to make some room in the middle buffer */
893 if (left) {
894 u32 left_nr;
895 left_nr = btrfs_header_nritems(left);
896 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
897 wret = 1;
898 } else {
899 ret = btrfs_cow_block(trans, root, left, parent,
900 pslot - 1, &left);
901 if (ret)
902 wret = 1;
903 else {
904 wret = push_node_left(trans, root,
905 left, mid);
906 }
907 }
908 if (wret < 0)
909 ret = wret;
910 if (wret == 0) {
911 struct btrfs_disk_key disk_key;
912 orig_slot += left_nr;
913 btrfs_node_key(mid, &disk_key, 0);
914 btrfs_set_node_key(parent, &disk_key, pslot);
915 btrfs_mark_buffer_dirty(parent);
916 if (btrfs_header_nritems(left) > orig_slot) {
917 path->nodes[level] = left;
918 path->slots[level + 1] -= 1;
919 path->slots[level] = orig_slot;
920 free_extent_buffer(mid);
921 } else {
922 orig_slot -=
923 btrfs_header_nritems(left);
924 path->slots[level] = orig_slot;
925 free_extent_buffer(left);
926 }
927 return 0;
928 }
929 free_extent_buffer(left);
930 }
931 right= read_node_slot(root, parent, pslot + 1);
932
933 /*
934 * then try to empty the right most buffer into the middle
935 */
936 if (right) {
937 u32 right_nr;
938 right_nr = btrfs_header_nritems(right);
939 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
940 wret = 1;
941 } else {
942 ret = btrfs_cow_block(trans, root, right,
943 parent, pslot + 1,
944 &right);
945 if (ret)
946 wret = 1;
947 else {
948 wret = balance_node_right(trans, root,
949 right, mid);
950 }
951 }
952 if (wret < 0)
953 ret = wret;
954 if (wret == 0) {
955 struct btrfs_disk_key disk_key;
956
957 btrfs_node_key(right, &disk_key, 0);
958 btrfs_set_node_key(parent, &disk_key, pslot + 1);
959 btrfs_mark_buffer_dirty(parent);
960
961 if (btrfs_header_nritems(mid) <= orig_slot) {
962 path->nodes[level] = right;
963 path->slots[level + 1] += 1;
964 path->slots[level] = orig_slot -
965 btrfs_header_nritems(mid);
966 free_extent_buffer(mid);
967 } else {
968 free_extent_buffer(right);
969 }
970 return 0;
971 }
972 free_extent_buffer(right);
973 }
974 return 1;
975 }
976
977 /*
978 * readahead one full node of leaves
979 */
980 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
981 int level, int slot, u64 objectid)
982 {
983 struct extent_buffer *node;
984 struct btrfs_disk_key disk_key;
985 u32 nritems;
986 u64 search;
987 u64 lowest_read;
988 u64 highest_read;
989 u64 nread = 0;
990 int direction = path->reada;
991 struct extent_buffer *eb;
992 u32 nr;
993 u32 blocksize;
994 u32 nscan = 0;
995
996 if (level != 1)
997 return;
998
999 if (!path->nodes[level])
1000 return;
1001
1002 node = path->nodes[level];
1003 search = btrfs_node_blockptr(node, slot);
1004 blocksize = btrfs_level_size(root, level - 1);
1005 eb = btrfs_find_tree_block(root, search, blocksize);
1006 if (eb) {
1007 free_extent_buffer(eb);
1008 return;
1009 }
1010
1011 highest_read = search;
1012 lowest_read = search;
1013
1014 nritems = btrfs_header_nritems(node);
1015 nr = slot;
1016 while(1) {
1017 if (direction < 0) {
1018 if (nr == 0)
1019 break;
1020 nr--;
1021 } else if (direction > 0) {
1022 nr++;
1023 if (nr >= nritems)
1024 break;
1025 }
1026 if (path->reada < 0 && objectid) {
1027 btrfs_node_key(node, &disk_key, nr);
1028 if (btrfs_disk_key_objectid(&disk_key) != objectid)
1029 break;
1030 }
1031 search = btrfs_node_blockptr(node, nr);
1032 if ((search >= lowest_read && search <= highest_read) ||
1033 (search < lowest_read && lowest_read - search <= 32768) ||
1034 (search > highest_read && search - highest_read <= 32768)) {
1035 readahead_tree_block(root, search, blocksize);
1036 nread += blocksize;
1037 }
1038 nscan++;
1039 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
1040 break;
1041 if(nread > (1024 * 1024) || nscan > 128)
1042 break;
1043
1044 if (search < lowest_read)
1045 lowest_read = search;
1046 if (search > highest_read)
1047 highest_read = search;
1048 }
1049 }
1050
1051 /*
1052 * look for key in the tree. path is filled in with nodes along the way
1053 * if key is found, we return zero and you can find the item in the leaf
1054 * level of the path (level 0)
1055 *
1056 * If the key isn't found, the path points to the slot where it should
1057 * be inserted, and 1 is returned. If there are other errors during the
1058 * search a negative error number is returned.
1059 *
1060 * if ins_len > 0, nodes and leaves will be split as we walk down the
1061 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
1062 * possible)
1063 */
1064 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
1065 *root, struct btrfs_key *key, struct btrfs_path *p, int
1066 ins_len, int cow)
1067 {
1068 struct extent_buffer *b;
1069 u64 bytenr;
1070 u64 ptr_gen;
1071 int slot;
1072 int ret;
1073 int level;
1074 int should_reada = p->reada;
1075 u8 lowest_level = 0;
1076
1077 lowest_level = p->lowest_level;
1078 WARN_ON(lowest_level && ins_len);
1079 WARN_ON(p->nodes[0] != NULL);
1080 /*
1081 WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
1082 */
1083 again:
1084 b = root->node;
1085 extent_buffer_get(b);
1086 while (b) {
1087 level = btrfs_header_level(b);
1088 if (cow) {
1089 int wret;
1090 wret = btrfs_cow_block(trans, root, b,
1091 p->nodes[level + 1],
1092 p->slots[level + 1],
1093 &b);
1094 if (wret) {
1095 free_extent_buffer(b);
1096 return wret;
1097 }
1098 }
1099 BUG_ON(!cow && ins_len);
1100 if (level != btrfs_header_level(b))
1101 WARN_ON(1);
1102 level = btrfs_header_level(b);
1103 p->nodes[level] = b;
1104 ret = check_block(root, p, level);
1105 if (ret)
1106 return -1;
1107 ret = bin_search(b, key, level, &slot);
1108 if (level != 0) {
1109 if (ret && slot > 0)
1110 slot -= 1;
1111 p->slots[level] = slot;
1112 if (ins_len > 0 && btrfs_header_nritems(b) >=
1113 BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1114 int sret = split_node(trans, root, p, level);
1115 BUG_ON(sret > 0);
1116 if (sret)
1117 return sret;
1118 b = p->nodes[level];
1119 slot = p->slots[level];
1120 } else if (ins_len < 0) {
1121 int sret = balance_level(trans, root, p,
1122 level);
1123 if (sret)
1124 return sret;
1125 b = p->nodes[level];
1126 if (!b) {
1127 btrfs_release_path(NULL, p);
1128 goto again;
1129 }
1130 slot = p->slots[level];
1131 BUG_ON(btrfs_header_nritems(b) == 1);
1132 }
1133 /* this is only true while dropping a snapshot */
1134 if (level == lowest_level)
1135 break;
1136 bytenr = btrfs_node_blockptr(b, slot);
1137 ptr_gen = btrfs_node_ptr_generation(b, slot);
1138 if (should_reada)
1139 reada_for_search(root, p, level, slot,
1140 key->objectid);
1141 b = read_tree_block(root, bytenr,
1142 btrfs_level_size(root, level - 1));
1143 if (ptr_gen != btrfs_header_generation(b)) {
1144 printk("block %llu bad gen wanted %llu "
1145 "found %llu\n",
1146 (unsigned long long)b->start,
1147 (unsigned long long)ptr_gen,
1148 (unsigned long long)btrfs_header_generation(b));
1149 }
1150 } else {
1151 p->slots[level] = slot;
1152 if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1153 sizeof(struct btrfs_item) + ins_len) {
1154 int sret = split_leaf(trans, root, key,
1155 p, ins_len, ret == 0);
1156 BUG_ON(sret > 0);
1157 if (sret)
1158 return sret;
1159 }
1160 return ret;
1161 }
1162 }
1163 return 1;
1164 }
1165
1166 /*
1167 * adjust the pointers going up the tree, starting at level
1168 * making sure the right key of each node is points to 'key'.
1169 * This is used after shifting pointers to the left, so it stops
1170 * fixing up pointers when a given leaf/node is not in slot 0 of the
1171 * higher levels
1172 *
1173 * If this fails to write a tree block, it returns -1, but continues
1174 * fixing up the blocks in ram so the tree is consistent.
1175 */
1176 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1177 struct btrfs_root *root, struct btrfs_path *path,
1178 struct btrfs_disk_key *key, int level)
1179 {
1180 int i;
1181 int ret = 0;
1182 struct extent_buffer *t;
1183
1184 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1185 int tslot = path->slots[i];
1186 if (!path->nodes[i])
1187 break;
1188 t = path->nodes[i];
1189 btrfs_set_node_key(t, key, tslot);
1190 btrfs_mark_buffer_dirty(path->nodes[i]);
1191 if (tslot != 0)
1192 break;
1193 }
1194 return ret;
1195 }
1196
1197 /*
1198 * try to push data from one node into the next node left in the
1199 * tree.
1200 *
1201 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1202 * error, and > 0 if there was no room in the left hand block.
1203 */
1204 static int push_node_left(struct btrfs_trans_handle *trans,
1205 struct btrfs_root *root, struct extent_buffer *dst,
1206 struct extent_buffer *src)
1207 {
1208 int push_items = 0;
1209 int src_nritems;
1210 int dst_nritems;
1211 int ret = 0;
1212
1213 src_nritems = btrfs_header_nritems(src);
1214 dst_nritems = btrfs_header_nritems(dst);
1215 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1216 WARN_ON(btrfs_header_generation(src) != trans->transid);
1217 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1218
1219 if (push_items <= 0) {
1220 return 1;
1221 }
1222
1223 if (src_nritems < push_items)
1224 push_items = src_nritems;
1225
1226 copy_extent_buffer(dst, src,
1227 btrfs_node_key_ptr_offset(dst_nritems),
1228 btrfs_node_key_ptr_offset(0),
1229 push_items * sizeof(struct btrfs_key_ptr));
1230
1231 if (push_items < src_nritems) {
1232 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1233 btrfs_node_key_ptr_offset(push_items),
1234 (src_nritems - push_items) *
1235 sizeof(struct btrfs_key_ptr));
1236 }
1237 btrfs_set_header_nritems(src, src_nritems - push_items);
1238 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1239 btrfs_mark_buffer_dirty(src);
1240 btrfs_mark_buffer_dirty(dst);
1241 return ret;
1242 }
1243
1244 /*
1245 * try to push data from one node into the next node right in the
1246 * tree.
1247 *
1248 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1249 * error, and > 0 if there was no room in the right hand block.
1250 *
1251 * this will only push up to 1/2 the contents of the left node over
1252 */
1253 static int balance_node_right(struct btrfs_trans_handle *trans,
1254 struct btrfs_root *root,
1255 struct extent_buffer *dst,
1256 struct extent_buffer *src)
1257 {
1258 int push_items = 0;
1259 int max_push;
1260 int src_nritems;
1261 int dst_nritems;
1262 int ret = 0;
1263
1264 WARN_ON(btrfs_header_generation(src) != trans->transid);
1265 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1266
1267 src_nritems = btrfs_header_nritems(src);
1268 dst_nritems = btrfs_header_nritems(dst);
1269 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1270 if (push_items <= 0)
1271 return 1;
1272
1273 max_push = src_nritems / 2 + 1;
1274 /* don't try to empty the node */
1275 if (max_push >= src_nritems)
1276 return 1;
1277
1278 if (max_push < push_items)
1279 push_items = max_push;
1280
1281 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1282 btrfs_node_key_ptr_offset(0),
1283 (dst_nritems) *
1284 sizeof(struct btrfs_key_ptr));
1285
1286 copy_extent_buffer(dst, src,
1287 btrfs_node_key_ptr_offset(0),
1288 btrfs_node_key_ptr_offset(src_nritems - push_items),
1289 push_items * sizeof(struct btrfs_key_ptr));
1290
1291 btrfs_set_header_nritems(src, src_nritems - push_items);
1292 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1293
1294 btrfs_mark_buffer_dirty(src);
1295 btrfs_mark_buffer_dirty(dst);
1296 return ret;
1297 }
1298
1299 /*
1300 * helper function to insert a new root level in the tree.
1301 * A new node is allocated, and a single item is inserted to
1302 * point to the existing root
1303 *
1304 * returns zero on success or < 0 on failure.
1305 */
1306 static int noinline insert_new_root(struct btrfs_trans_handle *trans,
1307 struct btrfs_root *root,
1308 struct btrfs_path *path, int level)
1309 {
1310 u64 root_gen;
1311 u64 lower_gen;
1312 struct extent_buffer *lower;
1313 struct extent_buffer *c;
1314 struct btrfs_disk_key lower_key;
1315
1316 BUG_ON(path->nodes[level]);
1317 BUG_ON(path->nodes[level-1] != root->node);
1318
1319 if (root->ref_cows)
1320 root_gen = trans->transid;
1321 else
1322 root_gen = 0;
1323
1324 lower = path->nodes[level-1];
1325 if (level == 1)
1326 btrfs_item_key(lower, &lower_key, 0);
1327 else
1328 btrfs_node_key(lower, &lower_key, 0);
1329
1330 c = __btrfs_alloc_free_block(trans, root, root->nodesize,
1331 root->root_key.objectid,
1332 root_gen, lower_key.objectid, level,
1333 root->node->start, 0);
1334 if (IS_ERR(c))
1335 return PTR_ERR(c);
1336 memset_extent_buffer(c, 0, 0, root->nodesize);
1337 btrfs_set_header_nritems(c, 1);
1338 btrfs_set_header_level(c, level);
1339 btrfs_set_header_bytenr(c, c->start);
1340 btrfs_set_header_generation(c, trans->transid);
1341 btrfs_set_header_owner(c, root->root_key.objectid);
1342
1343 write_extent_buffer(c, root->fs_info->fsid,
1344 (unsigned long)btrfs_header_fsid(c),
1345 BTRFS_FSID_SIZE);
1346 btrfs_set_node_key(c, &lower_key, 0);
1347 btrfs_set_node_blockptr(c, 0, lower->start);
1348 lower_gen = btrfs_header_generation(lower);
1349 WARN_ON(lower_gen == 0);
1350
1351 btrfs_set_node_ptr_generation(c, 0, lower_gen);
1352
1353 btrfs_mark_buffer_dirty(c);
1354
1355 /* the super has an extra ref to root->node */
1356 free_extent_buffer(root->node);
1357 root->node = c;
1358 add_root_to_dirty_list(root);
1359 extent_buffer_get(c);
1360 path->nodes[level] = c;
1361 path->slots[level] = 0;
1362
1363 if (root->ref_cows && lower_gen != trans->transid) {
1364 struct btrfs_path *back_path = btrfs_alloc_path();
1365 int ret;
1366 ret = btrfs_insert_extent_backref(trans,
1367 root->fs_info->extent_root,
1368 path, lower->start,
1369 root->root_key.objectid,
1370 trans->transid, 0, 0);
1371 BUG_ON(ret);
1372 btrfs_free_path(back_path);
1373 }
1374 return 0;
1375 }
1376
1377 /*
1378 * worker function to insert a single pointer in a node.
1379 * the node should have enough room for the pointer already
1380 *
1381 * slot and level indicate where you want the key to go, and
1382 * blocknr is the block the key points to.
1383 *
1384 * returns zero on success and < 0 on any error
1385 */
1386 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1387 *root, struct btrfs_path *path, struct btrfs_disk_key
1388 *key, u64 bytenr, int slot, int level)
1389 {
1390 struct extent_buffer *lower;
1391 int nritems;
1392
1393 BUG_ON(!path->nodes[level]);
1394 lower = path->nodes[level];
1395 nritems = btrfs_header_nritems(lower);
1396 if (slot > nritems)
1397 BUG();
1398 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1399 BUG();
1400 if (slot != nritems) {
1401 memmove_extent_buffer(lower,
1402 btrfs_node_key_ptr_offset(slot + 1),
1403 btrfs_node_key_ptr_offset(slot),
1404 (nritems - slot) * sizeof(struct btrfs_key_ptr));
1405 }
1406 btrfs_set_node_key(lower, key, slot);
1407 btrfs_set_node_blockptr(lower, slot, bytenr);
1408 WARN_ON(trans->transid == 0);
1409 btrfs_set_node_ptr_generation(lower, slot, trans->transid);
1410 btrfs_set_header_nritems(lower, nritems + 1);
1411 btrfs_mark_buffer_dirty(lower);
1412 return 0;
1413 }
1414
1415 /*
1416 * split the node at the specified level in path in two.
1417 * The path is corrected to point to the appropriate node after the split
1418 *
1419 * Before splitting this tries to make some room in the node by pushing
1420 * left and right, if either one works, it returns right away.
1421 *
1422 * returns 0 on success and < 0 on failure
1423 */
1424 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1425 *root, struct btrfs_path *path, int level)
1426 {
1427 u64 root_gen;
1428 struct extent_buffer *c;
1429 struct extent_buffer *split;
1430 struct btrfs_disk_key disk_key;
1431 int mid;
1432 int ret;
1433 int wret;
1434 u32 c_nritems;
1435
1436 c = path->nodes[level];
1437 WARN_ON(btrfs_header_generation(c) != trans->transid);
1438 if (c == root->node) {
1439 /* trying to split the root, lets make a new one */
1440 ret = insert_new_root(trans, root, path, level + 1);
1441 if (ret)
1442 return ret;
1443 } else {
1444 ret = push_nodes_for_insert(trans, root, path, level);
1445 c = path->nodes[level];
1446 if (!ret && btrfs_header_nritems(c) <
1447 BTRFS_NODEPTRS_PER_BLOCK(root) - 1)
1448 return 0;
1449 if (ret < 0)
1450 return ret;
1451 }
1452
1453 c_nritems = btrfs_header_nritems(c);
1454 if (root->ref_cows)
1455 root_gen = trans->transid;
1456 else
1457 root_gen = 0;
1458
1459 btrfs_node_key(c, &disk_key, 0);
1460 split = __btrfs_alloc_free_block(trans, root, root->nodesize,
1461 root->root_key.objectid,
1462 root_gen,
1463 btrfs_disk_key_objectid(&disk_key),
1464 level, c->start, 0);
1465 if (IS_ERR(split))
1466 return PTR_ERR(split);
1467
1468 btrfs_set_header_flags(split, btrfs_header_flags(c));
1469 btrfs_set_header_level(split, btrfs_header_level(c));
1470 btrfs_set_header_bytenr(split, split->start);
1471 btrfs_set_header_generation(split, trans->transid);
1472 btrfs_set_header_owner(split, root->root_key.objectid);
1473 btrfs_set_header_flags(split, 0);
1474 write_extent_buffer(split, root->fs_info->fsid,
1475 (unsigned long)btrfs_header_fsid(split),
1476 BTRFS_FSID_SIZE);
1477
1478 mid = (c_nritems + 1) / 2;
1479
1480 copy_extent_buffer(split, c,
1481 btrfs_node_key_ptr_offset(0),
1482 btrfs_node_key_ptr_offset(mid),
1483 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1484 btrfs_set_header_nritems(split, c_nritems - mid);
1485 btrfs_set_header_nritems(c, mid);
1486 ret = 0;
1487
1488 btrfs_mark_buffer_dirty(c);
1489 btrfs_mark_buffer_dirty(split);
1490
1491 btrfs_node_key(split, &disk_key, 0);
1492 wret = insert_ptr(trans, root, path, &disk_key, split->start,
1493 path->slots[level + 1] + 1,
1494 level + 1);
1495 if (wret)
1496 ret = wret;
1497
1498 if (path->slots[level] >= mid) {
1499 path->slots[level] -= mid;
1500 free_extent_buffer(c);
1501 path->nodes[level] = split;
1502 path->slots[level + 1] += 1;
1503 } else {
1504 free_extent_buffer(split);
1505 }
1506 return ret;
1507 }
1508
1509 /*
1510 * how many bytes are required to store the items in a leaf. start
1511 * and nr indicate which items in the leaf to check. This totals up the
1512 * space used both by the item structs and the item data
1513 */
1514 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1515 {
1516 int data_len;
1517 int nritems = btrfs_header_nritems(l);
1518 int end = min(nritems, start + nr) - 1;
1519
1520 if (!nr)
1521 return 0;
1522 data_len = btrfs_item_end_nr(l, start);
1523 data_len = data_len - btrfs_item_offset_nr(l, end);
1524 data_len += sizeof(struct btrfs_item) * nr;
1525 WARN_ON(data_len < 0);
1526 return data_len;
1527 }
1528
1529 /*
1530 * The space between the end of the leaf items and
1531 * the start of the leaf data. IOW, how much room
1532 * the leaf has left for both items and data
1533 */
1534 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1535 {
1536 int nritems = btrfs_header_nritems(leaf);
1537 int ret;
1538 ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1539 if (ret < 0) {
1540 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1541 ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
1542 leaf_space_used(leaf, 0, nritems), nritems);
1543 }
1544 return ret;
1545 }
1546
1547 /*
1548 * push some data in the path leaf to the right, trying to free up at
1549 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1550 *
1551 * returns 1 if the push failed because the other node didn't have enough
1552 * room, 0 if everything worked out and < 0 if there were major errors.
1553 */
1554 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1555 *root, struct btrfs_path *path, int data_size,
1556 int empty)
1557 {
1558 struct extent_buffer *left = path->nodes[0];
1559 struct extent_buffer *right;
1560 struct extent_buffer *upper;
1561 struct btrfs_disk_key disk_key;
1562 int slot;
1563 u32 i;
1564 int free_space;
1565 int push_space = 0;
1566 int push_items = 0;
1567 struct btrfs_item *item;
1568 u32 left_nritems;
1569 u32 nr;
1570 u32 right_nritems;
1571 u32 data_end;
1572 u32 this_item_size;
1573 int ret;
1574
1575 slot = path->slots[1];
1576 if (!path->nodes[1]) {
1577 return 1;
1578 }
1579 upper = path->nodes[1];
1580 if (slot >= btrfs_header_nritems(upper) - 1)
1581 return 1;
1582
1583 right = read_tree_block(root, btrfs_node_blockptr(upper, slot + 1),
1584 root->leafsize);
1585 free_space = btrfs_leaf_free_space(root, right);
1586 if (free_space < data_size + sizeof(struct btrfs_item)) {
1587 free_extent_buffer(right);
1588 return 1;
1589 }
1590
1591 /* cow and double check */
1592 ret = btrfs_cow_block(trans, root, right, upper,
1593 slot + 1, &right);
1594 if (ret) {
1595 free_extent_buffer(right);
1596 return 1;
1597 }
1598 free_space = btrfs_leaf_free_space(root, right);
1599 if (free_space < data_size + sizeof(struct btrfs_item)) {
1600 free_extent_buffer(right);
1601 return 1;
1602 }
1603
1604 left_nritems = btrfs_header_nritems(left);
1605 if (left_nritems == 0) {
1606 free_extent_buffer(right);
1607 return 1;
1608 }
1609
1610 if (empty)
1611 nr = 0;
1612 else
1613 nr = 1;
1614
1615 i = left_nritems - 1;
1616 while (i >= nr) {
1617 item = btrfs_item_nr(left, i);
1618
1619 if (path->slots[0] == i)
1620 push_space += data_size + sizeof(*item);
1621
1622 this_item_size = btrfs_item_size(left, item);
1623 if (this_item_size + sizeof(*item) + push_space > free_space)
1624 break;
1625 push_items++;
1626 push_space += this_item_size + sizeof(*item);
1627 if (i == 0)
1628 break;
1629 i--;
1630 }
1631
1632 if (push_items == 0) {
1633 free_extent_buffer(right);
1634 return 1;
1635 }
1636
1637 if (!empty && push_items == left_nritems)
1638 WARN_ON(1);
1639
1640 /* push left to right */
1641 right_nritems = btrfs_header_nritems(right);
1642
1643 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1644 push_space -= leaf_data_end(root, left);
1645
1646 /* make room in the right data area */
1647 data_end = leaf_data_end(root, right);
1648 memmove_extent_buffer(right,
1649 btrfs_leaf_data(right) + data_end - push_space,
1650 btrfs_leaf_data(right) + data_end,
1651 BTRFS_LEAF_DATA_SIZE(root) - data_end);
1652
1653 /* copy from the left data area */
1654 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1655 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1656 btrfs_leaf_data(left) + leaf_data_end(root, left),
1657 push_space);
1658
1659 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1660 btrfs_item_nr_offset(0),
1661 right_nritems * sizeof(struct btrfs_item));
1662
1663 /* copy the items from left to right */
1664 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1665 btrfs_item_nr_offset(left_nritems - push_items),
1666 push_items * sizeof(struct btrfs_item));
1667
1668 /* update the item pointers */
1669 right_nritems += push_items;
1670 btrfs_set_header_nritems(right, right_nritems);
1671 push_space = BTRFS_LEAF_DATA_SIZE(root);
1672 for (i = 0; i < right_nritems; i++) {
1673 item = btrfs_item_nr(right, i);
1674 push_space -= btrfs_item_size(right, item);
1675 btrfs_set_item_offset(right, item, push_space);
1676 }
1677
1678 left_nritems -= push_items;
1679 btrfs_set_header_nritems(left, left_nritems);
1680
1681 if (left_nritems)
1682 btrfs_mark_buffer_dirty(left);
1683 btrfs_mark_buffer_dirty(right);
1684
1685 btrfs_item_key(right, &disk_key, 0);
1686 btrfs_set_node_key(upper, &disk_key, slot + 1);
1687 btrfs_mark_buffer_dirty(upper);
1688
1689 /* then fixup the leaf pointer in the path */
1690 if (path->slots[0] >= left_nritems) {
1691 path->slots[0] -= left_nritems;
1692 free_extent_buffer(path->nodes[0]);
1693 path->nodes[0] = right;
1694 path->slots[1] += 1;
1695 } else {
1696 free_extent_buffer(right);
1697 }
1698 return 0;
1699 }
1700 /*
1701 * push some data in the path leaf to the left, trying to free up at
1702 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1703 */
1704 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1705 *root, struct btrfs_path *path, int data_size,
1706 int empty)
1707 {
1708 struct btrfs_disk_key disk_key;
1709 struct extent_buffer *right = path->nodes[0];
1710 struct extent_buffer *left;
1711 int slot;
1712 int i;
1713 int free_space;
1714 int push_space = 0;
1715 int push_items = 0;
1716 struct btrfs_item *item;
1717 u32 old_left_nritems;
1718 u32 right_nritems;
1719 u32 nr;
1720 int ret = 0;
1721 int wret;
1722 u32 this_item_size;
1723 u32 old_left_item_size;
1724
1725 slot = path->slots[1];
1726 if (slot == 0)
1727 return 1;
1728 if (!path->nodes[1])
1729 return 1;
1730
1731 right_nritems = btrfs_header_nritems(right);
1732 if (right_nritems == 0) {
1733 return 1;
1734 }
1735
1736 left = read_tree_block(root, btrfs_node_blockptr(path->nodes[1],
1737 slot - 1), root->leafsize);
1738 free_space = btrfs_leaf_free_space(root, left);
1739 if (free_space < data_size + sizeof(struct btrfs_item)) {
1740 free_extent_buffer(left);
1741 return 1;
1742 }
1743
1744 /* cow and double check */
1745 ret = btrfs_cow_block(trans, root, left,
1746 path->nodes[1], slot - 1, &left);
1747 if (ret) {
1748 /* we hit -ENOSPC, but it isn't fatal here */
1749 free_extent_buffer(left);
1750 return 1;
1751 }
1752
1753 free_space = btrfs_leaf_free_space(root, left);
1754 if (free_space < data_size + sizeof(struct btrfs_item)) {
1755 free_extent_buffer(left);
1756 return 1;
1757 }
1758
1759 if (empty)
1760 nr = right_nritems;
1761 else
1762 nr = right_nritems - 1;
1763
1764 for (i = 0; i < nr; i++) {
1765 item = btrfs_item_nr(right, i);
1766
1767 if (path->slots[0] == i)
1768 push_space += data_size + sizeof(*item);
1769
1770 this_item_size = btrfs_item_size(right, item);
1771 if (this_item_size + sizeof(*item) + push_space > free_space)
1772 break;
1773
1774 push_items++;
1775 push_space += this_item_size + sizeof(*item);
1776 }
1777
1778 if (push_items == 0) {
1779 free_extent_buffer(left);
1780 return 1;
1781 }
1782 if (!empty && push_items == btrfs_header_nritems(right))
1783 WARN_ON(1);
1784
1785 /* push data from right to left */
1786 copy_extent_buffer(left, right,
1787 btrfs_item_nr_offset(btrfs_header_nritems(left)),
1788 btrfs_item_nr_offset(0),
1789 push_items * sizeof(struct btrfs_item));
1790
1791 push_space = BTRFS_LEAF_DATA_SIZE(root) -
1792 btrfs_item_offset_nr(right, push_items -1);
1793
1794 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
1795 leaf_data_end(root, left) - push_space,
1796 btrfs_leaf_data(right) +
1797 btrfs_item_offset_nr(right, push_items - 1),
1798 push_space);
1799 old_left_nritems = btrfs_header_nritems(left);
1800 BUG_ON(old_left_nritems < 0);
1801
1802 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
1803 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1804 u32 ioff;
1805
1806 item = btrfs_item_nr(left, i);
1807 ioff = btrfs_item_offset(left, item);
1808 btrfs_set_item_offset(left, item,
1809 ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
1810 }
1811 btrfs_set_header_nritems(left, old_left_nritems + push_items);
1812
1813 /* fixup right node */
1814 if (push_items > right_nritems) {
1815 printk("push items %d nr %u\n", push_items, right_nritems);
1816 WARN_ON(1);
1817 }
1818
1819 if (push_items < right_nritems) {
1820 push_space = btrfs_item_offset_nr(right, push_items - 1) -
1821 leaf_data_end(root, right);
1822 memmove_extent_buffer(right, btrfs_leaf_data(right) +
1823 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1824 btrfs_leaf_data(right) +
1825 leaf_data_end(root, right), push_space);
1826
1827 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
1828 btrfs_item_nr_offset(push_items),
1829 (btrfs_header_nritems(right) - push_items) *
1830 sizeof(struct btrfs_item));
1831 }
1832 right_nritems -= push_items;
1833 btrfs_set_header_nritems(right, right_nritems);
1834 push_space = BTRFS_LEAF_DATA_SIZE(root);
1835 for (i = 0; i < right_nritems; i++) {
1836 item = btrfs_item_nr(right, i);
1837 push_space = push_space - btrfs_item_size(right, item);
1838 btrfs_set_item_offset(right, item, push_space);
1839 }
1840
1841 btrfs_mark_buffer_dirty(left);
1842 if (right_nritems)
1843 btrfs_mark_buffer_dirty(right);
1844
1845 btrfs_item_key(right, &disk_key, 0);
1846 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1847 if (wret)
1848 ret = wret;
1849
1850 /* then fixup the leaf pointer in the path */
1851 if (path->slots[0] < push_items) {
1852 path->slots[0] += old_left_nritems;
1853 free_extent_buffer(path->nodes[0]);
1854 path->nodes[0] = left;
1855 path->slots[1] -= 1;
1856 } else {
1857 free_extent_buffer(left);
1858 path->slots[0] -= push_items;
1859 }
1860 BUG_ON(path->slots[0] < 0);
1861 return ret;
1862 }
1863
1864 /*
1865 * split the path's leaf in two, making sure there is at least data_size
1866 * available for the resulting leaf level of the path.
1867 *
1868 * returns 0 if all went well and < 0 on failure.
1869 */
1870 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1871 *root, struct btrfs_key *ins_key,
1872 struct btrfs_path *path, int data_size, int extend)
1873 {
1874 u64 root_gen;
1875 struct extent_buffer *l;
1876 u32 nritems;
1877 int mid;
1878 int slot;
1879 struct extent_buffer *right;
1880 int space_needed = data_size + sizeof(struct btrfs_item);
1881 int data_copy_size;
1882 int rt_data_off;
1883 int i;
1884 int ret = 0;
1885 int wret;
1886 int double_split;
1887 int num_doubles = 0;
1888 struct btrfs_disk_key disk_key;
1889
1890 if (extend)
1891 space_needed = data_size;
1892
1893 if (root->ref_cows)
1894 root_gen = trans->transid;
1895 else
1896 root_gen = 0;
1897
1898 /* first try to make some room by pushing left and right */
1899 if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
1900 wret = push_leaf_right(trans, root, path, data_size, 0);
1901 if (wret < 0) {
1902 return wret;
1903 }
1904 if (wret) {
1905 wret = push_leaf_left(trans, root, path, data_size, 0);
1906 if (wret < 0)
1907 return wret;
1908 }
1909 l = path->nodes[0];
1910
1911 /* did the pushes work? */
1912 if (btrfs_leaf_free_space(root, l) >= space_needed)
1913 return 0;
1914 }
1915
1916 if (!path->nodes[1]) {
1917 ret = insert_new_root(trans, root, path, 1);
1918 if (ret)
1919 return ret;
1920 }
1921 again:
1922 double_split = 0;
1923 l = path->nodes[0];
1924 slot = path->slots[0];
1925 nritems = btrfs_header_nritems(l);
1926 mid = (nritems + 1)/ 2;
1927
1928 btrfs_item_key(l, &disk_key, 0);
1929
1930 right = __btrfs_alloc_free_block(trans, root, root->leafsize,
1931 root->root_key.objectid,
1932 root_gen, disk_key.objectid, 0,
1933 l->start, 0);
1934 if (IS_ERR(right))
1935 return PTR_ERR(right);
1936
1937 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
1938 btrfs_set_header_bytenr(right, right->start);
1939 btrfs_set_header_generation(right, trans->transid);
1940 btrfs_set_header_owner(right, root->root_key.objectid);
1941 btrfs_set_header_level(right, 0);
1942 write_extent_buffer(right, root->fs_info->fsid,
1943 (unsigned long)btrfs_header_fsid(right),
1944 BTRFS_FSID_SIZE);
1945 if (mid <= slot) {
1946 if (nritems == 1 ||
1947 leaf_space_used(l, mid, nritems - mid) + space_needed >
1948 BTRFS_LEAF_DATA_SIZE(root)) {
1949 if (slot >= nritems) {
1950 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1951 btrfs_set_header_nritems(right, 0);
1952 wret = insert_ptr(trans, root, path,
1953 &disk_key, right->start,
1954 path->slots[1] + 1, 1);
1955 if (wret)
1956 ret = wret;
1957 free_extent_buffer(path->nodes[0]);
1958 path->nodes[0] = right;
1959 path->slots[0] = 0;
1960 path->slots[1] += 1;
1961 return ret;
1962 }
1963 mid = slot;
1964 if (mid != nritems &&
1965 leaf_space_used(l, mid, nritems - mid) +
1966 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
1967 double_split = 1;
1968 }
1969 }
1970 } else {
1971 if (leaf_space_used(l, 0, mid + 1) + space_needed >
1972 BTRFS_LEAF_DATA_SIZE(root)) {
1973 if (!extend && slot == 0) {
1974 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1975 btrfs_set_header_nritems(right, 0);
1976 wret = insert_ptr(trans, root, path,
1977 &disk_key,
1978 right->start,
1979 path->slots[1], 1);
1980 if (wret)
1981 ret = wret;
1982 free_extent_buffer(path->nodes[0]);
1983 path->nodes[0] = right;
1984 path->slots[0] = 0;
1985 if (path->slots[1] == 0) {
1986 wret = fixup_low_keys(trans, root,
1987 path, &disk_key, 1);
1988 if (wret)
1989 ret = wret;
1990 }
1991 return ret;
1992 } else if (extend && slot == 0) {
1993 mid = 1;
1994 } else {
1995 mid = slot;
1996 if (mid != nritems &&
1997 leaf_space_used(l, mid, nritems - mid) +
1998 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
1999 double_split = 1;
2000 }
2001 }
2002 }
2003 }
2004 nritems = nritems - mid;
2005 btrfs_set_header_nritems(right, nritems);
2006 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
2007
2008 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
2009 btrfs_item_nr_offset(mid),
2010 nritems * sizeof(struct btrfs_item));
2011
2012 copy_extent_buffer(right, l,
2013 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
2014 data_copy_size, btrfs_leaf_data(l) +
2015 leaf_data_end(root, l), data_copy_size);
2016
2017 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
2018 btrfs_item_end_nr(l, mid);
2019
2020 for (i = 0; i < nritems; i++) {
2021 struct btrfs_item *item = btrfs_item_nr(right, i);
2022 u32 ioff = btrfs_item_offset(right, item);
2023 btrfs_set_item_offset(right, item, ioff + rt_data_off);
2024 }
2025
2026 btrfs_set_header_nritems(l, mid);
2027 ret = 0;
2028 btrfs_item_key(right, &disk_key, 0);
2029 wret = insert_ptr(trans, root, path, &disk_key, right->start,
2030 path->slots[1] + 1, 1);
2031 if (wret)
2032 ret = wret;
2033
2034 btrfs_mark_buffer_dirty(right);
2035 btrfs_mark_buffer_dirty(l);
2036 BUG_ON(path->slots[0] != slot);
2037
2038 if (mid <= slot) {
2039 free_extent_buffer(path->nodes[0]);
2040 path->nodes[0] = right;
2041 path->slots[0] -= mid;
2042 path->slots[1] += 1;
2043 } else
2044 free_extent_buffer(right);
2045
2046 BUG_ON(path->slots[0] < 0);
2047
2048 if (double_split) {
2049 BUG_ON(num_doubles != 0);
2050 num_doubles++;
2051 goto again;
2052 }
2053 return ret;
2054 }
2055
2056 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
2057 struct btrfs_root *root,
2058 struct btrfs_path *path,
2059 u32 new_size, int from_end)
2060 {
2061 int ret = 0;
2062 int slot;
2063 int slot_orig;
2064 struct extent_buffer *leaf;
2065 struct btrfs_item *item;
2066 u32 nritems;
2067 unsigned int data_end;
2068 unsigned int old_data_start;
2069 unsigned int old_size;
2070 unsigned int size_diff;
2071 int i;
2072
2073 slot_orig = path->slots[0];
2074 leaf = path->nodes[0];
2075 slot = path->slots[0];
2076
2077 old_size = btrfs_item_size_nr(leaf, slot);
2078 if (old_size == new_size)
2079 return 0;
2080
2081 nritems = btrfs_header_nritems(leaf);
2082 data_end = leaf_data_end(root, leaf);
2083
2084 old_data_start = btrfs_item_offset_nr(leaf, slot);
2085
2086 size_diff = old_size - new_size;
2087
2088 BUG_ON(slot < 0);
2089 BUG_ON(slot >= nritems);
2090
2091 /*
2092 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2093 */
2094 /* first correct the data pointers */
2095 for (i = slot; i < nritems; i++) {
2096 u32 ioff;
2097 item = btrfs_item_nr(leaf, i);
2098 ioff = btrfs_item_offset(leaf, item);
2099 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2100 }
2101
2102 /* shift the data */
2103 if (from_end) {
2104 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2105 data_end + size_diff, btrfs_leaf_data(leaf) +
2106 data_end, old_data_start + new_size - data_end);
2107 } else {
2108 struct btrfs_disk_key disk_key;
2109 u64 offset;
2110
2111 btrfs_item_key(leaf, &disk_key, slot);
2112
2113 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2114 unsigned long ptr;
2115 struct btrfs_file_extent_item *fi;
2116
2117 fi = btrfs_item_ptr(leaf, slot,
2118 struct btrfs_file_extent_item);
2119 fi = (struct btrfs_file_extent_item *)(
2120 (unsigned long)fi - size_diff);
2121
2122 if (btrfs_file_extent_type(leaf, fi) ==
2123 BTRFS_FILE_EXTENT_INLINE) {
2124 ptr = btrfs_item_ptr_offset(leaf, slot);
2125 memmove_extent_buffer(leaf, ptr,
2126 (unsigned long)fi,
2127 offsetof(struct btrfs_file_extent_item,
2128 disk_bytenr));
2129 }
2130 }
2131
2132 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2133 data_end + size_diff, btrfs_leaf_data(leaf) +
2134 data_end, old_data_start - data_end);
2135
2136 offset = btrfs_disk_key_offset(&disk_key);
2137 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2138 btrfs_set_item_key(leaf, &disk_key, slot);
2139 if (slot == 0)
2140 fixup_low_keys(trans, root, path, &disk_key, 1);
2141 }
2142
2143 item = btrfs_item_nr(leaf, slot);
2144 btrfs_set_item_size(leaf, item, new_size);
2145 btrfs_mark_buffer_dirty(leaf);
2146
2147 ret = 0;
2148 if (btrfs_leaf_free_space(root, leaf) < 0) {
2149 btrfs_print_leaf(root, leaf);
2150 BUG();
2151 }
2152 return ret;
2153 }
2154
2155 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2156 struct btrfs_root *root, struct btrfs_path *path,
2157 u32 data_size)
2158 {
2159 int ret = 0;
2160 int slot;
2161 int slot_orig;
2162 struct extent_buffer *leaf;
2163 struct btrfs_item *item;
2164 u32 nritems;
2165 unsigned int data_end;
2166 unsigned int old_data;
2167 unsigned int old_size;
2168 int i;
2169
2170 slot_orig = path->slots[0];
2171 leaf = path->nodes[0];
2172
2173 nritems = btrfs_header_nritems(leaf);
2174 data_end = leaf_data_end(root, leaf);
2175
2176 if (btrfs_leaf_free_space(root, leaf) < data_size) {
2177 btrfs_print_leaf(root, leaf);
2178 BUG();
2179 }
2180 slot = path->slots[0];
2181 old_data = btrfs_item_end_nr(leaf, slot);
2182
2183 BUG_ON(slot < 0);
2184 if (slot >= nritems) {
2185 btrfs_print_leaf(root, leaf);
2186 printk("slot %d too large, nritems %d\n", slot, nritems);
2187 BUG_ON(1);
2188 }
2189
2190 /*
2191 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2192 */
2193 /* first correct the data pointers */
2194 for (i = slot; i < nritems; i++) {
2195 u32 ioff;
2196 item = btrfs_item_nr(leaf, i);
2197 ioff = btrfs_item_offset(leaf, item);
2198 btrfs_set_item_offset(leaf, item, ioff - data_size);
2199 }
2200
2201 /* shift the data */
2202 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2203 data_end - data_size, btrfs_leaf_data(leaf) +
2204 data_end, old_data - data_end);
2205
2206 data_end = old_data;
2207 old_size = btrfs_item_size_nr(leaf, slot);
2208 item = btrfs_item_nr(leaf, slot);
2209 btrfs_set_item_size(leaf, item, old_size + data_size);
2210 btrfs_mark_buffer_dirty(leaf);
2211
2212 ret = 0;
2213 if (btrfs_leaf_free_space(root, leaf) < 0) {
2214 btrfs_print_leaf(root, leaf);
2215 BUG();
2216 }
2217 return ret;
2218 }
2219
2220 /*
2221 * Given a key and some data, insert an item into the tree.
2222 * This does all the path init required, making room in the tree if needed.
2223 */
2224 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
2225 struct btrfs_root *root,
2226 struct btrfs_path *path,
2227 struct btrfs_key *cpu_key, u32 *data_size,
2228 int nr)
2229 {
2230 struct extent_buffer *leaf;
2231 struct btrfs_item *item;
2232 int ret = 0;
2233 int slot;
2234 int slot_orig;
2235 int i;
2236 u32 nritems;
2237 u32 total_size = 0;
2238 u32 total_data = 0;
2239 unsigned int data_end;
2240 struct btrfs_disk_key disk_key;
2241
2242 for (i = 0; i < nr; i++) {
2243 total_data += data_size[i];
2244 }
2245
2246 /* create a root if there isn't one */
2247 if (!root->node)
2248 BUG();
2249
2250 total_size = total_data + (nr - 1) * sizeof(struct btrfs_item);
2251 ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
2252 if (ret == 0) {
2253 return -EEXIST;
2254 }
2255 if (ret < 0)
2256 goto out;
2257
2258 slot_orig = path->slots[0];
2259 leaf = path->nodes[0];
2260
2261 nritems = btrfs_header_nritems(leaf);
2262 data_end = leaf_data_end(root, leaf);
2263
2264 if (btrfs_leaf_free_space(root, leaf) <
2265 sizeof(struct btrfs_item) + total_size) {
2266 btrfs_print_leaf(root, leaf);
2267 printk("not enough freespace need %u have %d\n",
2268 total_size, btrfs_leaf_free_space(root, leaf));
2269 BUG();
2270 }
2271
2272 slot = path->slots[0];
2273 BUG_ON(slot < 0);
2274
2275 if (slot != nritems) {
2276 int i;
2277 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2278
2279 if (old_data < data_end) {
2280 btrfs_print_leaf(root, leaf);
2281 printk("slot %d old_data %d data_end %d\n",
2282 slot, old_data, data_end);
2283 BUG_ON(1);
2284 }
2285 /*
2286 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2287 */
2288 /* first correct the data pointers */
2289 for (i = slot; i < nritems; i++) {
2290 u32 ioff;
2291
2292 item = btrfs_item_nr(leaf, i);
2293 ioff = btrfs_item_offset(leaf, item);
2294 btrfs_set_item_offset(leaf, item, ioff - total_data);
2295 }
2296
2297 /* shift the items */
2298 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
2299 btrfs_item_nr_offset(slot),
2300 (nritems - slot) * sizeof(struct btrfs_item));
2301
2302 /* shift the data */
2303 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2304 data_end - total_data, btrfs_leaf_data(leaf) +
2305 data_end, old_data - data_end);
2306 data_end = old_data;
2307 }
2308
2309 /* setup the item for the new data */
2310 for (i = 0; i < nr; i++) {
2311 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
2312 btrfs_set_item_key(leaf, &disk_key, slot + i);
2313 item = btrfs_item_nr(leaf, slot + i);
2314 btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
2315 data_end -= data_size[i];
2316 btrfs_set_item_size(leaf, item, data_size[i]);
2317 }
2318 btrfs_set_header_nritems(leaf, nritems + nr);
2319 btrfs_mark_buffer_dirty(leaf);
2320
2321 ret = 0;
2322 if (slot == 0) {
2323 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2324 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2325 }
2326
2327 if (btrfs_leaf_free_space(root, leaf) < 0) {
2328 btrfs_print_leaf(root, leaf);
2329 BUG();
2330 }
2331
2332 out:
2333 return ret;
2334 }
2335
2336 /*
2337 * Given a key and some data, insert an item into the tree.
2338 * This does all the path init required, making room in the tree if needed.
2339 */
2340 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2341 *root, struct btrfs_key *cpu_key, void *data, u32
2342 data_size)
2343 {
2344 int ret = 0;
2345 struct btrfs_path *path;
2346 struct extent_buffer *leaf;
2347 unsigned long ptr;
2348
2349 path = btrfs_alloc_path();
2350 BUG_ON(!path);
2351 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2352 if (!ret) {
2353 leaf = path->nodes[0];
2354 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2355 write_extent_buffer(leaf, data, ptr, data_size);
2356 btrfs_mark_buffer_dirty(leaf);
2357 }
2358 btrfs_free_path(path);
2359 return ret;
2360 }
2361
2362 /*
2363 * delete the pointer from a given node.
2364 *
2365 * If the delete empties a node, the node is removed from the tree,
2366 * continuing all the way the root if required. The root is converted into
2367 * a leaf if all the nodes are emptied.
2368 */
2369 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2370 struct btrfs_path *path, int level, int slot)
2371 {
2372 struct extent_buffer *parent = path->nodes[level];
2373 u32 nritems;
2374 int ret = 0;
2375 int wret;
2376
2377 nritems = btrfs_header_nritems(parent);
2378 if (slot != nritems -1) {
2379 memmove_extent_buffer(parent,
2380 btrfs_node_key_ptr_offset(slot),
2381 btrfs_node_key_ptr_offset(slot + 1),
2382 sizeof(struct btrfs_key_ptr) *
2383 (nritems - slot - 1));
2384 }
2385 nritems--;
2386 btrfs_set_header_nritems(parent, nritems);
2387 if (nritems == 0 && parent == root->node) {
2388 BUG_ON(btrfs_header_level(root->node) != 1);
2389 /* just turn the root into a leaf and break */
2390 btrfs_set_header_level(root->node, 0);
2391 } else if (slot == 0) {
2392 struct btrfs_disk_key disk_key;
2393
2394 btrfs_node_key(parent, &disk_key, 0);
2395 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2396 if (wret)
2397 ret = wret;
2398 }
2399 btrfs_mark_buffer_dirty(parent);
2400 return ret;
2401 }
2402
2403 /*
2404 * delete the item at the leaf level in path. If that empties
2405 * the leaf, remove it from the tree
2406 */
2407 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2408 struct btrfs_path *path, int slot, int nr)
2409 {
2410 struct extent_buffer *leaf;
2411 struct btrfs_item *item;
2412 int last_off;
2413 int dsize = 0;
2414 int ret = 0;
2415 int wret;
2416 int i;
2417 u32 nritems;
2418
2419 leaf = path->nodes[0];
2420 last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
2421
2422 for (i = 0; i < nr; i++)
2423 dsize += btrfs_item_size_nr(leaf, slot + i);
2424
2425 nritems = btrfs_header_nritems(leaf);
2426
2427 if (slot + nr != nritems) {
2428 int i;
2429 int data_end = leaf_data_end(root, leaf);
2430
2431 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2432 data_end + dsize,
2433 btrfs_leaf_data(leaf) + data_end,
2434 last_off - data_end);
2435
2436 for (i = slot + nr; i < nritems; i++) {
2437 u32 ioff;
2438
2439 item = btrfs_item_nr(leaf, i);
2440 ioff = btrfs_item_offset(leaf, item);
2441 btrfs_set_item_offset(leaf, item, ioff + dsize);
2442 }
2443
2444 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2445 btrfs_item_nr_offset(slot + nr),
2446 sizeof(struct btrfs_item) *
2447 (nritems - slot - nr));
2448 }
2449 btrfs_set_header_nritems(leaf, nritems - nr);
2450 nritems -= nr;
2451
2452 /* delete the leaf if we've emptied it */
2453 if (nritems == 0) {
2454 if (leaf == root->node) {
2455 btrfs_set_header_level(leaf, 0);
2456 } else {
2457 u64 root_gen = btrfs_header_generation(path->nodes[1]);
2458 clean_tree_block(trans, root, leaf);
2459 wait_on_tree_block_writeback(root, leaf);
2460 wret = del_ptr(trans, root, path, 1, path->slots[1]);
2461 if (wret)
2462 ret = wret;
2463 wret = btrfs_free_extent(trans, root,
2464 leaf->start, leaf->len,
2465 btrfs_header_owner(path->nodes[1]),
2466 root_gen, 0, 0, 1);
2467 if (wret)
2468 ret = wret;
2469 }
2470 } else {
2471 int used = leaf_space_used(leaf, 0, nritems);
2472 if (slot == 0) {
2473 struct btrfs_disk_key disk_key;
2474
2475 btrfs_item_key(leaf, &disk_key, 0);
2476 wret = fixup_low_keys(trans, root, path,
2477 &disk_key, 1);
2478 if (wret)
2479 ret = wret;
2480 }
2481
2482 /* delete the leaf if it is mostly empty */
2483 if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
2484 /* push_leaf_left fixes the path.
2485 * make sure the path still points to our leaf
2486 * for possible call to del_ptr below
2487 */
2488 slot = path->slots[1];
2489 extent_buffer_get(leaf);
2490
2491 wret = push_leaf_left(trans, root, path, 1, 1);
2492 if (wret < 0 && wret != -ENOSPC)
2493 ret = wret;
2494
2495 if (path->nodes[0] == leaf &&
2496 btrfs_header_nritems(leaf)) {
2497 wret = push_leaf_right(trans, root, path, 1, 1);
2498 if (wret < 0 && wret != -ENOSPC)
2499 ret = wret;
2500 }
2501
2502 if (btrfs_header_nritems(leaf) == 0) {
2503 u64 root_gen;
2504 u64 bytenr = leaf->start;
2505 u32 blocksize = leaf->len;
2506
2507 root_gen = btrfs_header_generation(
2508 path->nodes[1]);
2509
2510 clean_tree_block(trans, root, leaf);
2511 wait_on_tree_block_writeback(root, leaf);
2512
2513 wret = del_ptr(trans, root, path, 1, slot);
2514 if (wret)
2515 ret = wret;
2516
2517 free_extent_buffer(leaf);
2518 wret = btrfs_free_extent(trans, root, bytenr,
2519 blocksize,
2520 btrfs_header_owner(path->nodes[1]),
2521 root_gen, 0, 0, 1);
2522 if (wret)
2523 ret = wret;
2524 } else {
2525 btrfs_mark_buffer_dirty(leaf);
2526 free_extent_buffer(leaf);
2527 }
2528 } else {
2529 btrfs_mark_buffer_dirty(leaf);
2530 }
2531 }
2532 return ret;
2533 }
2534
2535 /*
2536 * walk up the tree as far as required to find the previous leaf.
2537 * returns 0 if it found something or 1 if there are no lesser leaves.
2538 * returns < 0 on io errors.
2539 */
2540 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
2541 {
2542 u64 bytenr;
2543 int slot;
2544 int level = 1;
2545 struct extent_buffer *c;
2546 struct extent_buffer *next = NULL;
2547
2548 while(level < BTRFS_MAX_LEVEL) {
2549 if (!path->nodes[level])
2550 return 1;
2551
2552 slot = path->slots[level];
2553 c = path->nodes[level];
2554 if (slot == 0) {
2555 level++;
2556 if (level == BTRFS_MAX_LEVEL)
2557 return 1;
2558 continue;
2559 }
2560 slot--;
2561
2562 bytenr = btrfs_node_blockptr(c, slot);
2563 if (next)
2564 free_extent_buffer(next);
2565
2566 next = read_tree_block(root, bytenr,
2567 btrfs_level_size(root, level - 1));
2568 break;
2569 }
2570 path->slots[level] = slot;
2571 while(1) {
2572 level--;
2573 c = path->nodes[level];
2574 free_extent_buffer(c);
2575 slot = btrfs_header_nritems(next);
2576 if (slot != 0)
2577 slot--;
2578 path->nodes[level] = next;
2579 path->slots[level] = slot;
2580 if (!level)
2581 break;
2582 next = read_tree_block(root, btrfs_node_blockptr(next, slot),
2583 btrfs_level_size(root, level - 1));
2584 }
2585 return 0;
2586 }
2587
2588 /*
2589 * walk up the tree as far as required to find the next leaf.
2590 * returns 0 if it found something or 1 if there are no greater leaves.
2591 * returns < 0 on io errors.
2592 */
2593 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2594 {
2595 int slot;
2596 int level = 1;
2597 u64 bytenr;
2598 struct extent_buffer *c;
2599 struct extent_buffer *next = NULL;
2600
2601 while(level < BTRFS_MAX_LEVEL) {
2602 if (!path->nodes[level])
2603 return 1;
2604
2605 slot = path->slots[level] + 1;
2606 c = path->nodes[level];
2607 if (slot >= btrfs_header_nritems(c)) {
2608 level++;
2609 if (level == BTRFS_MAX_LEVEL)
2610 return 1;
2611 continue;
2612 }
2613
2614 bytenr = btrfs_node_blockptr(c, slot);
2615 if (next)
2616 free_extent_buffer(next);
2617
2618 if (path->reada)
2619 reada_for_search(root, path, level, slot, 0);
2620
2621 next = read_tree_block(root, bytenr,
2622 btrfs_level_size(root, level -1));
2623 break;
2624 }
2625 path->slots[level] = slot;
2626 while(1) {
2627 level--;
2628 c = path->nodes[level];
2629 free_extent_buffer(c);
2630 path->nodes[level] = next;
2631 path->slots[level] = 0;
2632 if (!level)
2633 break;
2634 if (path->reada)
2635 reada_for_search(root, path, level, 0, 0);
2636 next = read_tree_block(root, btrfs_node_blockptr(next, 0),
2637 btrfs_level_size(root, level - 1));
2638 }
2639 return 0;
2640 }
2641
2642 int btrfs_previous_item(struct btrfs_root *root,
2643 struct btrfs_path *path, u64 min_objectid,
2644 int type)
2645 {
2646 struct btrfs_key found_key;
2647 struct extent_buffer *leaf;
2648 int ret;
2649
2650 while(1) {
2651 if (path->slots[0] == 0) {
2652 ret = btrfs_prev_leaf(root, path);
2653 if (ret != 0)
2654 return ret;
2655 } else {
2656 path->slots[0]--;
2657 }
2658 leaf = path->nodes[0];
2659 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2660 if (found_key.type == type)
2661 return 0;
2662 }
2663 return 1;
2664 }
2665
(deprecated) Btrfs progs developments and patch integration