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Change btrfs_map_block to return a structure with mappings for all stripes
[btrfs-progs-unstable/devel.git] / ctree.c
blob9f904620b0b6f9cc8bfa04a7408afd6e34dc2bfa
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 !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
249 *cow_ret = buf;
250 return 0;
251 }
252
253 search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
254 ret = __btrfs_cow_block(trans, root, buf, parent,
255 parent_slot, cow_ret, search_start, 0);
256 return ret;
257 }
258
259 /*
260 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
261 {
262 if (blocknr < other && other - (blocknr + blocksize) < 32768)
263 return 1;
264 if (blocknr > other && blocknr - (other + blocksize) < 32768)
265 return 1;
266 return 0;
267 }
268 */
269
270 /*
271 * compare two keys in a memcmp fashion
272 */
273 int btrfs_comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
274 {
275 struct btrfs_key k1;
276
277 btrfs_disk_key_to_cpu(&k1, disk);
278
279 if (k1.objectid > k2->objectid)
280 return 1;
281 if (k1.objectid < k2->objectid)
282 return -1;
283 if (k1.type > k2->type)
284 return 1;
285 if (k1.type < k2->type)
286 return -1;
287 if (k1.offset > k2->offset)
288 return 1;
289 if (k1.offset < k2->offset)
290 return -1;
291 return 0;
292 }
293
294
295 #if 0
296 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
297 struct btrfs_root *root, struct extent_buffer *parent,
298 int start_slot, int cache_only, u64 *last_ret,
299 struct btrfs_key *progress)
300 {
301 struct extent_buffer *cur;
302 struct extent_buffer *tmp;
303 u64 blocknr;
304 u64 search_start = *last_ret;
305 u64 last_block = 0;
306 u64 other;
307 u32 parent_nritems;
308 int end_slot;
309 int i;
310 int err = 0;
311 int parent_level;
312 int uptodate;
313 u32 blocksize;
314 int progress_passed = 0;
315 struct btrfs_disk_key disk_key;
316
317 parent_level = btrfs_header_level(parent);
318 if (cache_only && parent_level != 1)
319 return 0;
320
321 if (trans->transaction != root->fs_info->running_transaction) {
322 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
323 root->fs_info->running_transaction->transid);
324 WARN_ON(1);
325 }
326 if (trans->transid != root->fs_info->generation) {
327 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
328 root->fs_info->generation);
329 WARN_ON(1);
330 }
331
332 parent_nritems = btrfs_header_nritems(parent);
333 blocksize = btrfs_level_size(root, parent_level - 1);
334 end_slot = parent_nritems;
335
336 if (parent_nritems == 1)
337 return 0;
338
339 for (i = start_slot; i < end_slot; i++) {
340 int close = 1;
341
342 if (!parent->map_token) {
343 map_extent_buffer(parent,
344 btrfs_node_key_ptr_offset(i),
345 sizeof(struct btrfs_key_ptr),
346 &parent->map_token, &parent->kaddr,
347 &parent->map_start, &parent->map_len,
348 KM_USER1);
349 }
350 btrfs_node_key(parent, &disk_key, i);
351 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
352 continue;
353
354 progress_passed = 1;
355 blocknr = btrfs_node_blockptr(parent, i);
356 if (last_block == 0)
357 last_block = blocknr;
358
359 if (i > 0) {
360 other = btrfs_node_blockptr(parent, i - 1);
361 close = close_blocks(blocknr, other, blocksize);
362 }
363 if (close && i < end_slot - 2) {
364 other = btrfs_node_blockptr(parent, i + 1);
365 close = close_blocks(blocknr, other, blocksize);
366 }
367 if (close) {
368 last_block = blocknr;
369 continue;
370 }
371 if (parent->map_token) {
372 unmap_extent_buffer(parent, parent->map_token,
373 KM_USER1);
374 parent->map_token = NULL;
375 }
376
377 cur = btrfs_find_tree_block(root, blocknr, blocksize);
378 if (cur)
379 uptodate = btrfs_buffer_uptodate(cur);
380 else
381 uptodate = 0;
382 if (!cur || !uptodate) {
383 if (cache_only) {
384 free_extent_buffer(cur);
385 continue;
386 }
387 if (!cur) {
388 cur = read_tree_block(root, blocknr,
389 blocksize);
390 } else if (!uptodate) {
391 btrfs_read_buffer(cur);
392 }
393 }
394 if (search_start == 0)
395 search_start = last_block;
396
397 err = __btrfs_cow_block(trans, root, cur, parent, i,
398 &tmp, search_start,
399 min(16 * blocksize,
400 (end_slot - i) * blocksize));
401 if (err) {
402 free_extent_buffer(cur);
403 break;
404 }
405 search_start = tmp->start;
406 last_block = tmp->start;
407 *last_ret = search_start;
408 if (parent_level == 1)
409 btrfs_clear_buffer_defrag(tmp);
410 free_extent_buffer(tmp);
411 }
412 if (parent->map_token) {
413 unmap_extent_buffer(parent, parent->map_token,
414 KM_USER1);
415 parent->map_token = NULL;
416 }
417 return err;
418 }
419 #endif
420
421 /*
422 * The leaf data grows from end-to-front in the node.
423 * this returns the address of the start of the last item,
424 * which is the stop of the leaf data stack
425 */
426 static inline unsigned int leaf_data_end(struct btrfs_root *root,
427 struct extent_buffer *leaf)
428 {
429 u32 nr = btrfs_header_nritems(leaf);
430 if (nr == 0)
431 return BTRFS_LEAF_DATA_SIZE(root);
432 return btrfs_item_offset_nr(leaf, nr - 1);
433 }
434
435 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
436 int level)
437 {
438 struct extent_buffer *parent = NULL;
439 struct extent_buffer *node = path->nodes[level];
440 struct btrfs_disk_key parent_key;
441 struct btrfs_disk_key node_key;
442 int parent_slot;
443 int slot;
444 struct btrfs_key cpukey;
445 u32 nritems = btrfs_header_nritems(node);
446
447 if (path->nodes[level + 1])
448 parent = path->nodes[level + 1];
449
450 slot = path->slots[level];
451 BUG_ON(nritems == 0);
452 if (parent) {
453 parent_slot = path->slots[level + 1];
454 btrfs_node_key(parent, &parent_key, parent_slot);
455 btrfs_node_key(node, &node_key, 0);
456 BUG_ON(memcmp(&parent_key, &node_key,
457 sizeof(struct btrfs_disk_key)));
458 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
459 btrfs_header_bytenr(node));
460 }
461 BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
462 if (slot != 0) {
463 btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
464 btrfs_node_key(node, &node_key, slot);
465 BUG_ON(btrfs_comp_keys(&node_key, &cpukey) <= 0);
466 }
467 if (slot < nritems - 1) {
468 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
469 btrfs_node_key(node, &node_key, slot);
470 BUG_ON(btrfs_comp_keys(&node_key, &cpukey) >= 0);
471 }
472 return 0;
473 }
474
475 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
476 int level)
477 {
478 struct extent_buffer *leaf = path->nodes[level];
479 struct extent_buffer *parent = NULL;
480 int parent_slot;
481 struct btrfs_key cpukey;
482 struct btrfs_disk_key parent_key;
483 struct btrfs_disk_key leaf_key;
484 int slot = path->slots[0];
485
486 u32 nritems = btrfs_header_nritems(leaf);
487
488 if (path->nodes[level + 1])
489 parent = path->nodes[level + 1];
490
491 if (nritems == 0)
492 return 0;
493
494 if (parent) {
495 parent_slot = path->slots[level + 1];
496 btrfs_node_key(parent, &parent_key, parent_slot);
497 btrfs_item_key(leaf, &leaf_key, 0);
498
499 BUG_ON(memcmp(&parent_key, &leaf_key,
500 sizeof(struct btrfs_disk_key)));
501 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
502 btrfs_header_bytenr(leaf));
503 }
504 #if 0
505 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
506 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
507 btrfs_item_key(leaf, &leaf_key, i);
508 if (comp_keys(&leaf_key, &cpukey) >= 0) {
509 btrfs_print_leaf(root, leaf);
510 printk("slot %d offset bad key\n", i);
511 BUG_ON(1);
512 }
513 if (btrfs_item_offset_nr(leaf, i) !=
514 btrfs_item_end_nr(leaf, i + 1)) {
515 btrfs_print_leaf(root, leaf);
516 printk("slot %d offset bad\n", i);
517 BUG_ON(1);
518 }
519 if (i == 0) {
520 if (btrfs_item_offset_nr(leaf, i) +
521 btrfs_item_size_nr(leaf, i) !=
522 BTRFS_LEAF_DATA_SIZE(root)) {
523 btrfs_print_leaf(root, leaf);
524 printk("slot %d first offset bad\n", i);
525 BUG_ON(1);
526 }
527 }
528 }
529 if (nritems > 0) {
530 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
531 btrfs_print_leaf(root, leaf);
532 printk("slot %d bad size \n", nritems - 1);
533 BUG_ON(1);
534 }
535 }
536 #endif
537 if (slot != 0 && slot < nritems - 1) {
538 btrfs_item_key(leaf, &leaf_key, slot);
539 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
540 if (btrfs_comp_keys(&leaf_key, &cpukey) <= 0) {
541 btrfs_print_leaf(root, leaf);
542 printk("slot %d offset bad key\n", slot);
543 BUG_ON(1);
544 }
545 if (btrfs_item_offset_nr(leaf, slot - 1) !=
546 btrfs_item_end_nr(leaf, slot)) {
547 btrfs_print_leaf(root, leaf);
548 printk("slot %d offset bad\n", slot);
549 BUG_ON(1);
550 }
551 }
552 if (slot < nritems - 1) {
553 btrfs_item_key(leaf, &leaf_key, slot);
554 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
555 BUG_ON(btrfs_comp_keys(&leaf_key, &cpukey) >= 0);
556 if (btrfs_item_offset_nr(leaf, slot) !=
557 btrfs_item_end_nr(leaf, slot + 1)) {
558 btrfs_print_leaf(root, leaf);
559 printk("slot %d offset bad\n", slot);
560 BUG_ON(1);
561 }
562 }
563 BUG_ON(btrfs_item_offset_nr(leaf, 0) +
564 btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
565 return 0;
566 }
567
568 static int noinline check_block(struct btrfs_root *root,
569 struct btrfs_path *path, int level)
570 {
571 return 0;
572 #if 0
573 struct extent_buffer *buf = path->nodes[level];
574
575 if (memcmp_extent_buffer(buf, root->fs_info->fsid,
576 (unsigned long)btrfs_header_fsid(buf),
577 BTRFS_FSID_SIZE)) {
578 printk("warning bad block %Lu\n", buf->start);
579 return 1;
580 }
581 #endif
582 if (level == 0)
583 return check_leaf(root, path, level);
584 return check_node(root, path, level);
585 }
586
587 /*
588 * search for key in the extent_buffer. The items start at offset p,
589 * and they are item_size apart. There are 'max' items in p.
590 *
591 * the slot in the array is returned via slot, and it points to
592 * the place where you would insert key if it is not found in
593 * the array.
594 *
595 * slot may point to max if the key is bigger than all of the keys
596 */
597 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
598 int item_size, struct btrfs_key *key,
599 int max, int *slot)
600 {
601 int low = 0;
602 int high = max;
603 int mid;
604 int ret;
605 unsigned long offset;
606 struct btrfs_disk_key *tmp;
607
608 while(low < high) {
609 mid = (low + high) / 2;
610 offset = p + mid * item_size;
611
612 tmp = (struct btrfs_disk_key *)(eb->data + offset);
613 ret = btrfs_comp_keys(tmp, key);
614
615 if (ret < 0)
616 low = mid + 1;
617 else if (ret > 0)
618 high = mid;
619 else {
620 *slot = mid;
621 return 0;
622 }
623 }
624 *slot = low;
625 return 1;
626 }
627
628 /*
629 * simple bin_search frontend that does the right thing for
630 * leaves vs nodes
631 */
632 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
633 int level, int *slot)
634 {
635 if (level == 0) {
636 return generic_bin_search(eb,
637 offsetof(struct btrfs_leaf, items),
638 sizeof(struct btrfs_item),
639 key, btrfs_header_nritems(eb),
640 slot);
641 } else {
642 return generic_bin_search(eb,
643 offsetof(struct btrfs_node, ptrs),
644 sizeof(struct btrfs_key_ptr),
645 key, btrfs_header_nritems(eb),
646 slot);
647 }
648 return -1;
649 }
650
651 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
652 struct extent_buffer *parent, int slot)
653 {
654 if (slot < 0)
655 return NULL;
656 if (slot >= btrfs_header_nritems(parent))
657 return NULL;
658 return read_tree_block(root, btrfs_node_blockptr(parent, slot),
659 btrfs_level_size(root, btrfs_header_level(parent) - 1));
660 }
661
662 static int balance_level(struct btrfs_trans_handle *trans,
663 struct btrfs_root *root,
664 struct btrfs_path *path, int level)
665 {
666 struct extent_buffer *right = NULL;
667 struct extent_buffer *mid;
668 struct extent_buffer *left = NULL;
669 struct extent_buffer *parent = NULL;
670 int ret = 0;
671 int wret;
672 int pslot;
673 int orig_slot = path->slots[level];
674 int err_on_enospc = 0;
675 u64 orig_ptr;
676
677 if (level == 0)
678 return 0;
679
680 mid = path->nodes[level];
681 WARN_ON(btrfs_header_generation(mid) != trans->transid);
682
683 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
684
685 if (level < BTRFS_MAX_LEVEL - 1)
686 parent = path->nodes[level + 1];
687 pslot = path->slots[level + 1];
688
689 /*
690 * deal with the case where there is only one pointer in the root
691 * by promoting the node below to a root
692 */
693 if (!parent) {
694 struct extent_buffer *child;
695
696 if (btrfs_header_nritems(mid) != 1)
697 return 0;
698
699 /* promote the child to a root */
700 child = read_node_slot(root, mid, 0);
701 BUG_ON(!child);
702 ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
703 BUG_ON(ret);
704
705 root->node = child;
706 add_root_to_dirty_list(root);
707 path->nodes[level] = NULL;
708 clean_tree_block(trans, root, mid);
709 wait_on_tree_block_writeback(root, mid);
710 /* once for the path */
711 free_extent_buffer(mid);
712 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
713 root->root_key.objectid,
714 btrfs_header_generation(mid), 0, 0, 1);
715 /* once for the root ptr */
716 free_extent_buffer(mid);
717 return ret;
718 }
719 if (btrfs_header_nritems(mid) >
720 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
721 return 0;
722
723 if (btrfs_header_nritems(mid) < 2)
724 err_on_enospc = 1;
725
726 left = read_node_slot(root, parent, pslot - 1);
727 if (left) {
728 wret = btrfs_cow_block(trans, root, left,
729 parent, pslot - 1, &left);
730 if (wret) {
731 ret = wret;
732 goto enospc;
733 }
734 }
735 right = read_node_slot(root, parent, pslot + 1);
736 if (right) {
737 wret = btrfs_cow_block(trans, root, right,
738 parent, pslot + 1, &right);
739 if (wret) {
740 ret = wret;
741 goto enospc;
742 }
743 }
744
745 /* first, try to make some room in the middle buffer */
746 if (left) {
747 orig_slot += btrfs_header_nritems(left);
748 wret = push_node_left(trans, root, left, mid);
749 if (wret < 0)
750 ret = wret;
751 if (btrfs_header_nritems(mid) < 2)
752 err_on_enospc = 1;
753 }
754
755 /*
756 * then try to empty the right most buffer into the middle
757 */
758 if (right) {
759 wret = push_node_left(trans, root, mid, right);
760 if (wret < 0 && wret != -ENOSPC)
761 ret = wret;
762 if (btrfs_header_nritems(right) == 0) {
763 u64 bytenr = right->start;
764 u64 generation = btrfs_header_generation(parent);
765 u32 blocksize = right->len;
766
767 clean_tree_block(trans, root, right);
768 wait_on_tree_block_writeback(root, right);
769 free_extent_buffer(right);
770 right = NULL;
771 wret = del_ptr(trans, root, path, level + 1, pslot +
772 1);
773 if (wret)
774 ret = wret;
775 wret = btrfs_free_extent(trans, root, bytenr,
776 blocksize,
777 btrfs_header_owner(parent),
778 generation, 0, 0, 1);
779 if (wret)
780 ret = wret;
781 } else {
782 struct btrfs_disk_key right_key;
783 btrfs_node_key(right, &right_key, 0);
784 btrfs_set_node_key(parent, &right_key, pslot + 1);
785 btrfs_mark_buffer_dirty(parent);
786 }
787 }
788 if (btrfs_header_nritems(mid) == 1) {
789 /*
790 * we're not allowed to leave a node with one item in the
791 * tree during a delete. A deletion from lower in the tree
792 * could try to delete the only pointer in this node.
793 * So, pull some keys from the left.
794 * There has to be a left pointer at this point because
795 * otherwise we would have pulled some pointers from the
796 * right
797 */
798 BUG_ON(!left);
799 wret = balance_node_right(trans, root, mid, left);
800 if (wret < 0) {
801 ret = wret;
802 goto enospc;
803 }
804 BUG_ON(wret == 1);
805 }
806 if (btrfs_header_nritems(mid) == 0) {
807 /* we've managed to empty the middle node, drop it */
808 u64 root_gen = btrfs_header_generation(parent);
809 u64 bytenr = mid->start;
810 u32 blocksize = mid->len;
811 clean_tree_block(trans, root, mid);
812 wait_on_tree_block_writeback(root, mid);
813 free_extent_buffer(mid);
814 mid = NULL;
815 wret = del_ptr(trans, root, path, level + 1, pslot);
816 if (wret)
817 ret = wret;
818 wret = btrfs_free_extent(trans, root, bytenr, blocksize,
819 btrfs_header_owner(parent),
820 root_gen, 0, 0, 1);
821 if (wret)
822 ret = wret;
823 } else {
824 /* update the parent key to reflect our changes */
825 struct btrfs_disk_key mid_key;
826 btrfs_node_key(mid, &mid_key, 0);
827 btrfs_set_node_key(parent, &mid_key, pslot);
828 btrfs_mark_buffer_dirty(parent);
829 }
830
831 /* update the path */
832 if (left) {
833 if (btrfs_header_nritems(left) > orig_slot) {
834 extent_buffer_get(left);
835 path->nodes[level] = left;
836 path->slots[level + 1] -= 1;
837 path->slots[level] = orig_slot;
838 if (mid)
839 free_extent_buffer(mid);
840 } else {
841 orig_slot -= btrfs_header_nritems(left);
842 path->slots[level] = orig_slot;
843 }
844 }
845 /* double check we haven't messed things up */
846 check_block(root, path, level);
847 if (orig_ptr !=
848 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
849 BUG();
850 enospc:
851 if (right)
852 free_extent_buffer(right);
853 if (left)
854 free_extent_buffer(left);
855 return ret;
856 }
857
858 /* returns zero if the push worked, non-zero otherwise */
859 static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
860 struct btrfs_root *root,
861 struct btrfs_path *path, int level)
862 {
863 struct extent_buffer *right = NULL;
864 struct extent_buffer *mid;
865 struct extent_buffer *left = NULL;
866 struct extent_buffer *parent = NULL;
867 int ret = 0;
868 int wret;
869 int pslot;
870 int orig_slot = path->slots[level];
871 u64 orig_ptr;
872
873 if (level == 0)
874 return 1;
875
876 mid = path->nodes[level];
877 WARN_ON(btrfs_header_generation(mid) != trans->transid);
878 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
879
880 if (level < BTRFS_MAX_LEVEL - 1)
881 parent = path->nodes[level + 1];
882 pslot = path->slots[level + 1];
883
884 if (!parent)
885 return 1;
886
887 left = read_node_slot(root, parent, pslot - 1);
888
889 /* first, try to make some room in the middle buffer */
890 if (left) {
891 u32 left_nr;
892 left_nr = btrfs_header_nritems(left);
893 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
894 wret = 1;
895 } else {
896 ret = btrfs_cow_block(trans, root, left, parent,
897 pslot - 1, &left);
898 if (ret)
899 wret = 1;
900 else {
901 wret = push_node_left(trans, root,
902 left, mid);
903 }
904 }
905 if (wret < 0)
906 ret = wret;
907 if (wret == 0) {
908 struct btrfs_disk_key disk_key;
909 orig_slot += left_nr;
910 btrfs_node_key(mid, &disk_key, 0);
911 btrfs_set_node_key(parent, &disk_key, pslot);
912 btrfs_mark_buffer_dirty(parent);
913 if (btrfs_header_nritems(left) > orig_slot) {
914 path->nodes[level] = left;
915 path->slots[level + 1] -= 1;
916 path->slots[level] = orig_slot;
917 free_extent_buffer(mid);
918 } else {
919 orig_slot -=
920 btrfs_header_nritems(left);
921 path->slots[level] = orig_slot;
922 free_extent_buffer(left);
923 }
924 return 0;
925 }
926 free_extent_buffer(left);
927 }
928 right= read_node_slot(root, parent, pslot + 1);
929
930 /*
931 * then try to empty the right most buffer into the middle
932 */
933 if (right) {
934 u32 right_nr;
935 right_nr = btrfs_header_nritems(right);
936 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
937 wret = 1;
938 } else {
939 ret = btrfs_cow_block(trans, root, right,
940 parent, pslot + 1,
941 &right);
942 if (ret)
943 wret = 1;
944 else {
945 wret = balance_node_right(trans, root,
946 right, mid);
947 }
948 }
949 if (wret < 0)
950 ret = wret;
951 if (wret == 0) {
952 struct btrfs_disk_key disk_key;
953
954 btrfs_node_key(right, &disk_key, 0);
955 btrfs_set_node_key(parent, &disk_key, pslot + 1);
956 btrfs_mark_buffer_dirty(parent);
957
958 if (btrfs_header_nritems(mid) <= orig_slot) {
959 path->nodes[level] = right;
960 path->slots[level + 1] += 1;
961 path->slots[level] = orig_slot -
962 btrfs_header_nritems(mid);
963 free_extent_buffer(mid);
964 } else {
965 free_extent_buffer(right);
966 }
967 return 0;
968 }
969 free_extent_buffer(right);
970 }
971 return 1;
972 }
973
974 /*
975 * readahead one full node of leaves
976 */
977 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
978 int level, int slot, u64 objectid)
979 {
980 struct extent_buffer *node;
981 struct btrfs_disk_key disk_key;
982 u32 nritems;
983 u64 search;
984 u64 lowest_read;
985 u64 highest_read;
986 u64 nread = 0;
987 int direction = path->reada;
988 struct extent_buffer *eb;
989 u32 nr;
990 u32 blocksize;
991 u32 nscan = 0;
992
993 if (level != 1)
994 return;
995
996 if (!path->nodes[level])
997 return;
998
999 node = path->nodes[level];
1000 search = btrfs_node_blockptr(node, slot);
1001 blocksize = btrfs_level_size(root, level - 1);
1002 eb = btrfs_find_tree_block(root, search, blocksize);
1003 if (eb) {
1004 free_extent_buffer(eb);
1005 return;
1006 }
1007
1008 highest_read = search;
1009 lowest_read = search;
1010
1011 nritems = btrfs_header_nritems(node);
1012 nr = slot;
1013 while(1) {
1014 if (direction < 0) {
1015 if (nr == 0)
1016 break;
1017 nr--;
1018 } else if (direction > 0) {
1019 nr++;
1020 if (nr >= nritems)
1021 break;
1022 }
1023 if (path->reada < 0 && objectid) {
1024 btrfs_node_key(node, &disk_key, nr);
1025 if (btrfs_disk_key_objectid(&disk_key) != objectid)
1026 break;
1027 }
1028 search = btrfs_node_blockptr(node, nr);
1029 if ((search >= lowest_read && search <= highest_read) ||
1030 (search < lowest_read && lowest_read - search <= 32768) ||
1031 (search > highest_read && search - highest_read <= 32768)) {
1032 readahead_tree_block(root, search, blocksize);
1033 nread += blocksize;
1034 }
1035 nscan++;
1036 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
1037 break;
1038 if(nread > (1024 * 1024) || nscan > 128)
1039 break;
1040
1041 if (search < lowest_read)
1042 lowest_read = search;
1043 if (search > highest_read)
1044 highest_read = search;
1045 }
1046 }
1047
1048 /*
1049 * look for key in the tree. path is filled in with nodes along the way
1050 * if key is found, we return zero and you can find the item in the leaf
1051 * level of the path (level 0)
1052 *
1053 * If the key isn't found, the path points to the slot where it should
1054 * be inserted, and 1 is returned. If there are other errors during the
1055 * search a negative error number is returned.
1056 *
1057 * if ins_len > 0, nodes and leaves will be split as we walk down the
1058 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
1059 * possible)
1060 */
1061 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
1062 *root, struct btrfs_key *key, struct btrfs_path *p, int
1063 ins_len, int cow)
1064 {
1065 struct extent_buffer *b;
1066 u64 bytenr;
1067 u64 ptr_gen;
1068 int slot;
1069 int ret;
1070 int level;
1071 int should_reada = p->reada;
1072 u8 lowest_level = 0;
1073
1074 lowest_level = p->lowest_level;
1075 WARN_ON(lowest_level && ins_len);
1076 WARN_ON(p->nodes[0] != NULL);
1077 /*
1078 WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
1079 */
1080 again:
1081 b = root->node;
1082 extent_buffer_get(b);
1083 while (b) {
1084 level = btrfs_header_level(b);
1085 if (cow) {
1086 int wret;
1087 wret = btrfs_cow_block(trans, root, b,
1088 p->nodes[level + 1],
1089 p->slots[level + 1],
1090 &b);
1091 if (wret) {
1092 free_extent_buffer(b);
1093 return wret;
1094 }
1095 }
1096 BUG_ON(!cow && ins_len);
1097 if (level != btrfs_header_level(b))
1098 WARN_ON(1);
1099 level = btrfs_header_level(b);
1100 p->nodes[level] = b;
1101 ret = check_block(root, p, level);
1102 if (ret)
1103 return -1;
1104 ret = bin_search(b, key, level, &slot);
1105 if (level != 0) {
1106 if (ret && slot > 0)
1107 slot -= 1;
1108 p->slots[level] = slot;
1109 if (ins_len > 0 && btrfs_header_nritems(b) >=
1110 BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1111 int sret = split_node(trans, root, p, level);
1112 BUG_ON(sret > 0);
1113 if (sret)
1114 return sret;
1115 b = p->nodes[level];
1116 slot = p->slots[level];
1117 } else if (ins_len < 0) {
1118 int sret = balance_level(trans, root, p,
1119 level);
1120 if (sret)
1121 return sret;
1122 b = p->nodes[level];
1123 if (!b) {
1124 btrfs_release_path(NULL, p);
1125 goto again;
1126 }
1127 slot = p->slots[level];
1128 BUG_ON(btrfs_header_nritems(b) == 1);
1129 }
1130 /* this is only true while dropping a snapshot */
1131 if (level == lowest_level)
1132 break;
1133 bytenr = btrfs_node_blockptr(b, slot);
1134 ptr_gen = btrfs_node_ptr_generation(b, slot);
1135 if (should_reada)
1136 reada_for_search(root, p, level, slot,
1137 key->objectid);
1138 b = read_tree_block(root, bytenr,
1139 btrfs_level_size(root, level - 1));
1140 if (ptr_gen != btrfs_header_generation(b)) {
1141 printk("block %llu bad gen wanted %llu "
1142 "found %llu\n",
1143 (unsigned long long)b->start,
1144 (unsigned long long)ptr_gen,
1145 (unsigned long long)btrfs_header_generation(b));
1146 }
1147 } else {
1148 p->slots[level] = slot;
1149 if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1150 sizeof(struct btrfs_item) + ins_len) {
1151 int sret = split_leaf(trans, root, key,
1152 p, ins_len, ret == 0);
1153 BUG_ON(sret > 0);
1154 if (sret)
1155 return sret;
1156 }
1157 return ret;
1158 }
1159 }
1160 return 1;
1161 }
1162
1163 /*
1164 * adjust the pointers going up the tree, starting at level
1165 * making sure the right key of each node is points to 'key'.
1166 * This is used after shifting pointers to the left, so it stops
1167 * fixing up pointers when a given leaf/node is not in slot 0 of the
1168 * higher levels
1169 *
1170 * If this fails to write a tree block, it returns -1, but continues
1171 * fixing up the blocks in ram so the tree is consistent.
1172 */
1173 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1174 struct btrfs_root *root, struct btrfs_path *path,
1175 struct btrfs_disk_key *key, int level)
1176 {
1177 int i;
1178 int ret = 0;
1179 struct extent_buffer *t;
1180
1181 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1182 int tslot = path->slots[i];
1183 if (!path->nodes[i])
1184 break;
1185 t = path->nodes[i];
1186 btrfs_set_node_key(t, key, tslot);
1187 btrfs_mark_buffer_dirty(path->nodes[i]);
1188 if (tslot != 0)
1189 break;
1190 }
1191 return ret;
1192 }
1193
1194 /*
1195 * try to push data from one node into the next node left in the
1196 * tree.
1197 *
1198 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1199 * error, and > 0 if there was no room in the left hand block.
1200 */
1201 static int push_node_left(struct btrfs_trans_handle *trans,
1202 struct btrfs_root *root, struct extent_buffer *dst,
1203 struct extent_buffer *src)
1204 {
1205 int push_items = 0;
1206 int src_nritems;
1207 int dst_nritems;
1208 int ret = 0;
1209
1210 src_nritems = btrfs_header_nritems(src);
1211 dst_nritems = btrfs_header_nritems(dst);
1212 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1213 WARN_ON(btrfs_header_generation(src) != trans->transid);
1214 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1215
1216 if (push_items <= 0) {
1217 return 1;
1218 }
1219
1220 if (src_nritems < push_items)
1221 push_items = src_nritems;
1222
1223 copy_extent_buffer(dst, src,
1224 btrfs_node_key_ptr_offset(dst_nritems),
1225 btrfs_node_key_ptr_offset(0),
1226 push_items * sizeof(struct btrfs_key_ptr));
1227
1228 if (push_items < src_nritems) {
1229 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1230 btrfs_node_key_ptr_offset(push_items),
1231 (src_nritems - push_items) *
1232 sizeof(struct btrfs_key_ptr));
1233 }
1234 btrfs_set_header_nritems(src, src_nritems - push_items);
1235 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1236 btrfs_mark_buffer_dirty(src);
1237 btrfs_mark_buffer_dirty(dst);
1238 return ret;
1239 }
1240
1241 /*
1242 * try to push data from one node into the next node right in the
1243 * tree.
1244 *
1245 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1246 * error, and > 0 if there was no room in the right hand block.
1247 *
1248 * this will only push up to 1/2 the contents of the left node over
1249 */
1250 static int balance_node_right(struct btrfs_trans_handle *trans,
1251 struct btrfs_root *root,
1252 struct extent_buffer *dst,
1253 struct extent_buffer *src)
1254 {
1255 int push_items = 0;
1256 int max_push;
1257 int src_nritems;
1258 int dst_nritems;
1259 int ret = 0;
1260
1261 WARN_ON(btrfs_header_generation(src) != trans->transid);
1262 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1263
1264 src_nritems = btrfs_header_nritems(src);
1265 dst_nritems = btrfs_header_nritems(dst);
1266 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1267 if (push_items <= 0)
1268 return 1;
1269
1270 max_push = src_nritems / 2 + 1;
1271 /* don't try to empty the node */
1272 if (max_push >= src_nritems)
1273 return 1;
1274
1275 if (max_push < push_items)
1276 push_items = max_push;
1277
1278 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1279 btrfs_node_key_ptr_offset(0),
1280 (dst_nritems) *
1281 sizeof(struct btrfs_key_ptr));
1282
1283 copy_extent_buffer(dst, src,
1284 btrfs_node_key_ptr_offset(0),
1285 btrfs_node_key_ptr_offset(src_nritems - push_items),
1286 push_items * sizeof(struct btrfs_key_ptr));
1287
1288 btrfs_set_header_nritems(src, src_nritems - push_items);
1289 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1290
1291 btrfs_mark_buffer_dirty(src);
1292 btrfs_mark_buffer_dirty(dst);
1293 return ret;
1294 }
1295
1296 /*
1297 * helper function to insert a new root level in the tree.
1298 * A new node is allocated, and a single item is inserted to
1299 * point to the existing root
1300 *
1301 * returns zero on success or < 0 on failure.
1302 */
1303 static int noinline insert_new_root(struct btrfs_trans_handle *trans,
1304 struct btrfs_root *root,
1305 struct btrfs_path *path, int level)
1306 {
1307 u64 root_gen;
1308 u64 lower_gen;
1309 struct extent_buffer *lower;
1310 struct extent_buffer *c;
1311 struct btrfs_disk_key lower_key;
1312
1313 BUG_ON(path->nodes[level]);
1314 BUG_ON(path->nodes[level-1] != root->node);
1315
1316 if (root->ref_cows)
1317 root_gen = trans->transid;
1318 else
1319 root_gen = 0;
1320
1321 lower = path->nodes[level-1];
1322 if (level == 1)
1323 btrfs_item_key(lower, &lower_key, 0);
1324 else
1325 btrfs_node_key(lower, &lower_key, 0);
1326
1327 c = __btrfs_alloc_free_block(trans, root, root->nodesize,
1328 root->root_key.objectid,
1329 root_gen, lower_key.objectid, level,
1330 root->node->start, 0);
1331 if (IS_ERR(c))
1332 return PTR_ERR(c);
1333 memset_extent_buffer(c, 0, 0, root->nodesize);
1334 btrfs_set_header_nritems(c, 1);
1335 btrfs_set_header_level(c, level);
1336 btrfs_set_header_bytenr(c, c->start);
1337 btrfs_set_header_generation(c, trans->transid);
1338 btrfs_set_header_owner(c, root->root_key.objectid);
1339
1340 write_extent_buffer(c, root->fs_info->fsid,
1341 (unsigned long)btrfs_header_fsid(c),
1342 BTRFS_FSID_SIZE);
1343 btrfs_set_node_key(c, &lower_key, 0);
1344 btrfs_set_node_blockptr(c, 0, lower->start);
1345 lower_gen = btrfs_header_generation(lower);
1346 WARN_ON(lower_gen == 0);
1347
1348 btrfs_set_node_ptr_generation(c, 0, lower_gen);
1349
1350 btrfs_mark_buffer_dirty(c);
1351
1352 /* the super has an extra ref to root->node */
1353 free_extent_buffer(root->node);
1354 root->node = c;
1355 add_root_to_dirty_list(root);
1356 extent_buffer_get(c);
1357 path->nodes[level] = c;
1358 path->slots[level] = 0;
1359
1360 if (root->ref_cows && lower_gen != trans->transid) {
1361 struct btrfs_path *back_path = btrfs_alloc_path();
1362 int ret;
1363 ret = btrfs_insert_extent_backref(trans,
1364 root->fs_info->extent_root,
1365 path, lower->start,
1366 root->root_key.objectid,
1367 trans->transid, 0, 0);
1368 BUG_ON(ret);
1369 btrfs_free_path(back_path);
1370 }
1371 return 0;
1372 }
1373
1374 /*
1375 * worker function to insert a single pointer in a node.
1376 * the node should have enough room for the pointer already
1377 *
1378 * slot and level indicate where you want the key to go, and
1379 * blocknr is the block the key points to.
1380 *
1381 * returns zero on success and < 0 on any error
1382 */
1383 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1384 *root, struct btrfs_path *path, struct btrfs_disk_key
1385 *key, u64 bytenr, int slot, int level)
1386 {
1387 struct extent_buffer *lower;
1388 int nritems;
1389
1390 BUG_ON(!path->nodes[level]);
1391 lower = path->nodes[level];
1392 nritems = btrfs_header_nritems(lower);
1393 if (slot > nritems)
1394 BUG();
1395 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1396 BUG();
1397 if (slot != nritems) {
1398 memmove_extent_buffer(lower,
1399 btrfs_node_key_ptr_offset(slot + 1),
1400 btrfs_node_key_ptr_offset(slot),
1401 (nritems - slot) * sizeof(struct btrfs_key_ptr));
1402 }
1403 btrfs_set_node_key(lower, key, slot);
1404 btrfs_set_node_blockptr(lower, slot, bytenr);
1405 WARN_ON(trans->transid == 0);
1406 btrfs_set_node_ptr_generation(lower, slot, trans->transid);
1407 btrfs_set_header_nritems(lower, nritems + 1);
1408 btrfs_mark_buffer_dirty(lower);
1409 return 0;
1410 }
1411
1412 /*
1413 * split the node at the specified level in path in two.
1414 * The path is corrected to point to the appropriate node after the split
1415 *
1416 * Before splitting this tries to make some room in the node by pushing
1417 * left and right, if either one works, it returns right away.
1418 *
1419 * returns 0 on success and < 0 on failure
1420 */
1421 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1422 *root, struct btrfs_path *path, int level)
1423 {
1424 u64 root_gen;
1425 struct extent_buffer *c;
1426 struct extent_buffer *split;
1427 struct btrfs_disk_key disk_key;
1428 int mid;
1429 int ret;
1430 int wret;
1431 u32 c_nritems;
1432
1433 c = path->nodes[level];
1434 WARN_ON(btrfs_header_generation(c) != trans->transid);
1435 if (c == root->node) {
1436 /* trying to split the root, lets make a new one */
1437 ret = insert_new_root(trans, root, path, level + 1);
1438 if (ret)
1439 return ret;
1440 } else {
1441 ret = push_nodes_for_insert(trans, root, path, level);
1442 c = path->nodes[level];
1443 if (!ret && btrfs_header_nritems(c) <
1444 BTRFS_NODEPTRS_PER_BLOCK(root) - 1)
1445 return 0;
1446 if (ret < 0)
1447 return ret;
1448 }
1449
1450 c_nritems = btrfs_header_nritems(c);
1451 if (root->ref_cows)
1452 root_gen = trans->transid;
1453 else
1454 root_gen = 0;
1455
1456 btrfs_node_key(c, &disk_key, 0);
1457 split = __btrfs_alloc_free_block(trans, root, root->nodesize,
1458 root->root_key.objectid,
1459 root_gen,
1460 btrfs_disk_key_objectid(&disk_key),
1461 level, c->start, 0);
1462 if (IS_ERR(split))
1463 return PTR_ERR(split);
1464
1465 btrfs_set_header_flags(split, btrfs_header_flags(c));
1466 btrfs_set_header_level(split, btrfs_header_level(c));
1467 btrfs_set_header_bytenr(split, split->start);
1468 btrfs_set_header_generation(split, trans->transid);
1469 btrfs_set_header_owner(split, root->root_key.objectid);
1470 btrfs_set_header_flags(split, 0);
1471 write_extent_buffer(split, root->fs_info->fsid,
1472 (unsigned long)btrfs_header_fsid(split),
1473 BTRFS_FSID_SIZE);
1474
1475 mid = (c_nritems + 1) / 2;
1476
1477 copy_extent_buffer(split, c,
1478 btrfs_node_key_ptr_offset(0),
1479 btrfs_node_key_ptr_offset(mid),
1480 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1481 btrfs_set_header_nritems(split, c_nritems - mid);
1482 btrfs_set_header_nritems(c, mid);
1483 ret = 0;
1484
1485 btrfs_mark_buffer_dirty(c);
1486 btrfs_mark_buffer_dirty(split);
1487
1488 btrfs_node_key(split, &disk_key, 0);
1489 wret = insert_ptr(trans, root, path, &disk_key, split->start,
1490 path->slots[level + 1] + 1,
1491 level + 1);
1492 if (wret)
1493 ret = wret;
1494
1495 if (path->slots[level] >= mid) {
1496 path->slots[level] -= mid;
1497 free_extent_buffer(c);
1498 path->nodes[level] = split;
1499 path->slots[level + 1] += 1;
1500 } else {
1501 free_extent_buffer(split);
1502 }
1503 return ret;
1504 }
1505
1506 /*
1507 * how many bytes are required to store the items in a leaf. start
1508 * and nr indicate which items in the leaf to check. This totals up the
1509 * space used both by the item structs and the item data
1510 */
1511 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1512 {
1513 int data_len;
1514 int nritems = btrfs_header_nritems(l);
1515 int end = min(nritems, start + nr) - 1;
1516
1517 if (!nr)
1518 return 0;
1519 data_len = btrfs_item_end_nr(l, start);
1520 data_len = data_len - btrfs_item_offset_nr(l, end);
1521 data_len += sizeof(struct btrfs_item) * nr;
1522 WARN_ON(data_len < 0);
1523 return data_len;
1524 }
1525
1526 /*
1527 * The space between the end of the leaf items and
1528 * the start of the leaf data. IOW, how much room
1529 * the leaf has left for both items and data
1530 */
1531 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1532 {
1533 int nritems = btrfs_header_nritems(leaf);
1534 int ret;
1535 ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1536 if (ret < 0) {
1537 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1538 ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
1539 leaf_space_used(leaf, 0, nritems), nritems);
1540 }
1541 return ret;
1542 }
1543
1544 /*
1545 * push some data in the path leaf to the right, trying to free up at
1546 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1547 *
1548 * returns 1 if the push failed because the other node didn't have enough
1549 * room, 0 if everything worked out and < 0 if there were major errors.
1550 */
1551 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1552 *root, struct btrfs_path *path, int data_size,
1553 int empty)
1554 {
1555 struct extent_buffer *left = path->nodes[0];
1556 struct extent_buffer *right;
1557 struct extent_buffer *upper;
1558 struct btrfs_disk_key disk_key;
1559 int slot;
1560 u32 i;
1561 int free_space;
1562 int push_space = 0;
1563 int push_items = 0;
1564 struct btrfs_item *item;
1565 u32 left_nritems;
1566 u32 nr;
1567 u32 right_nritems;
1568 u32 data_end;
1569 u32 this_item_size;
1570 int ret;
1571
1572 slot = path->slots[1];
1573 if (!path->nodes[1]) {
1574 return 1;
1575 }
1576 upper = path->nodes[1];
1577 if (slot >= btrfs_header_nritems(upper) - 1)
1578 return 1;
1579
1580 right = read_tree_block(root, btrfs_node_blockptr(upper, slot + 1),
1581 root->leafsize);
1582 free_space = btrfs_leaf_free_space(root, right);
1583 if (free_space < data_size + sizeof(struct btrfs_item)) {
1584 free_extent_buffer(right);
1585 return 1;
1586 }
1587
1588 /* cow and double check */
1589 ret = btrfs_cow_block(trans, root, right, upper,
1590 slot + 1, &right);
1591 if (ret) {
1592 free_extent_buffer(right);
1593 return 1;
1594 }
1595 free_space = btrfs_leaf_free_space(root, right);
1596 if (free_space < data_size + sizeof(struct btrfs_item)) {
1597 free_extent_buffer(right);
1598 return 1;
1599 }
1600
1601 left_nritems = btrfs_header_nritems(left);
1602 if (left_nritems == 0) {
1603 free_extent_buffer(right);
1604 return 1;
1605 }
1606
1607 if (empty)
1608 nr = 0;
1609 else
1610 nr = 1;
1611
1612 i = left_nritems - 1;
1613 while (i >= nr) {
1614 item = btrfs_item_nr(left, i);
1615
1616 if (path->slots[0] == i)
1617 push_space += data_size + sizeof(*item);
1618
1619 this_item_size = btrfs_item_size(left, item);
1620 if (this_item_size + sizeof(*item) + push_space > free_space)
1621 break;
1622 push_items++;
1623 push_space += this_item_size + sizeof(*item);
1624 if (i == 0)
1625 break;
1626 i--;
1627 }
1628
1629 if (push_items == 0) {
1630 free_extent_buffer(right);
1631 return 1;
1632 }
1633
1634 if (!empty && push_items == left_nritems)
1635 WARN_ON(1);
1636
1637 /* push left to right */
1638 right_nritems = btrfs_header_nritems(right);
1639
1640 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1641 push_space -= leaf_data_end(root, left);
1642
1643 /* make room in the right data area */
1644 data_end = leaf_data_end(root, right);
1645 memmove_extent_buffer(right,
1646 btrfs_leaf_data(right) + data_end - push_space,
1647 btrfs_leaf_data(right) + data_end,
1648 BTRFS_LEAF_DATA_SIZE(root) - data_end);
1649
1650 /* copy from the left data area */
1651 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1652 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1653 btrfs_leaf_data(left) + leaf_data_end(root, left),
1654 push_space);
1655
1656 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1657 btrfs_item_nr_offset(0),
1658 right_nritems * sizeof(struct btrfs_item));
1659
1660 /* copy the items from left to right */
1661 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1662 btrfs_item_nr_offset(left_nritems - push_items),
1663 push_items * sizeof(struct btrfs_item));
1664
1665 /* update the item pointers */
1666 right_nritems += push_items;
1667 btrfs_set_header_nritems(right, right_nritems);
1668 push_space = BTRFS_LEAF_DATA_SIZE(root);
1669 for (i = 0; i < right_nritems; i++) {
1670 item = btrfs_item_nr(right, i);
1671 push_space -= btrfs_item_size(right, item);
1672 btrfs_set_item_offset(right, item, push_space);
1673 }
1674
1675 left_nritems -= push_items;
1676 btrfs_set_header_nritems(left, left_nritems);
1677
1678 if (left_nritems)
1679 btrfs_mark_buffer_dirty(left);
1680 btrfs_mark_buffer_dirty(right);
1681
1682 btrfs_item_key(right, &disk_key, 0);
1683 btrfs_set_node_key(upper, &disk_key, slot + 1);
1684 btrfs_mark_buffer_dirty(upper);
1685
1686 /* then fixup the leaf pointer in the path */
1687 if (path->slots[0] >= left_nritems) {
1688 path->slots[0] -= left_nritems;
1689 free_extent_buffer(path->nodes[0]);
1690 path->nodes[0] = right;
1691 path->slots[1] += 1;
1692 } else {
1693 free_extent_buffer(right);
1694 }
1695 return 0;
1696 }
1697 /*
1698 * push some data in the path leaf to the left, trying to free up at
1699 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1700 */
1701 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1702 *root, struct btrfs_path *path, int data_size,
1703 int empty)
1704 {
1705 struct btrfs_disk_key disk_key;
1706 struct extent_buffer *right = path->nodes[0];
1707 struct extent_buffer *left;
1708 int slot;
1709 int i;
1710 int free_space;
1711 int push_space = 0;
1712 int push_items = 0;
1713 struct btrfs_item *item;
1714 u32 old_left_nritems;
1715 u32 right_nritems;
1716 u32 nr;
1717 int ret = 0;
1718 int wret;
1719 u32 this_item_size;
1720 u32 old_left_item_size;
1721
1722 slot = path->slots[1];
1723 if (slot == 0)
1724 return 1;
1725 if (!path->nodes[1])
1726 return 1;
1727
1728 right_nritems = btrfs_header_nritems(right);
1729 if (right_nritems == 0) {
1730 return 1;
1731 }
1732
1733 left = read_tree_block(root, btrfs_node_blockptr(path->nodes[1],
1734 slot - 1), root->leafsize);
1735 free_space = btrfs_leaf_free_space(root, left);
1736 if (free_space < data_size + sizeof(struct btrfs_item)) {
1737 free_extent_buffer(left);
1738 return 1;
1739 }
1740
1741 /* cow and double check */
1742 ret = btrfs_cow_block(trans, root, left,
1743 path->nodes[1], slot - 1, &left);
1744 if (ret) {
1745 /* we hit -ENOSPC, but it isn't fatal here */
1746 free_extent_buffer(left);
1747 return 1;
1748 }
1749
1750 free_space = btrfs_leaf_free_space(root, left);
1751 if (free_space < data_size + sizeof(struct btrfs_item)) {
1752 free_extent_buffer(left);
1753 return 1;
1754 }
1755
1756 if (empty)
1757 nr = right_nritems;
1758 else
1759 nr = right_nritems - 1;
1760
1761 for (i = 0; i < nr; i++) {
1762 item = btrfs_item_nr(right, i);
1763
1764 if (path->slots[0] == i)
1765 push_space += data_size + sizeof(*item);
1766
1767 this_item_size = btrfs_item_size(right, item);
1768 if (this_item_size + sizeof(*item) + push_space > free_space)
1769 break;
1770
1771 push_items++;
1772 push_space += this_item_size + sizeof(*item);
1773 }
1774
1775 if (push_items == 0) {
1776 free_extent_buffer(left);
1777 return 1;
1778 }
1779 if (!empty && push_items == btrfs_header_nritems(right))
1780 WARN_ON(1);
1781
1782 /* push data from right to left */
1783 copy_extent_buffer(left, right,
1784 btrfs_item_nr_offset(btrfs_header_nritems(left)),
1785 btrfs_item_nr_offset(0),
1786 push_items * sizeof(struct btrfs_item));
1787
1788 push_space = BTRFS_LEAF_DATA_SIZE(root) -
1789 btrfs_item_offset_nr(right, push_items -1);
1790
1791 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
1792 leaf_data_end(root, left) - push_space,
1793 btrfs_leaf_data(right) +
1794 btrfs_item_offset_nr(right, push_items - 1),
1795 push_space);
1796 old_left_nritems = btrfs_header_nritems(left);
1797 BUG_ON(old_left_nritems < 0);
1798
1799 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
1800 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1801 u32 ioff;
1802
1803 item = btrfs_item_nr(left, i);
1804 ioff = btrfs_item_offset(left, item);
1805 btrfs_set_item_offset(left, item,
1806 ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
1807 }
1808 btrfs_set_header_nritems(left, old_left_nritems + push_items);
1809
1810 /* fixup right node */
1811 if (push_items > right_nritems) {
1812 printk("push items %d nr %u\n", push_items, right_nritems);
1813 WARN_ON(1);
1814 }
1815
1816 if (push_items < right_nritems) {
1817 push_space = btrfs_item_offset_nr(right, push_items - 1) -
1818 leaf_data_end(root, right);
1819 memmove_extent_buffer(right, btrfs_leaf_data(right) +
1820 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1821 btrfs_leaf_data(right) +
1822 leaf_data_end(root, right), push_space);
1823
1824 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
1825 btrfs_item_nr_offset(push_items),
1826 (btrfs_header_nritems(right) - push_items) *
1827 sizeof(struct btrfs_item));
1828 }
1829 right_nritems -= push_items;
1830 btrfs_set_header_nritems(right, right_nritems);
1831 push_space = BTRFS_LEAF_DATA_SIZE(root);
1832 for (i = 0; i < right_nritems; i++) {
1833 item = btrfs_item_nr(right, i);
1834 push_space = push_space - btrfs_item_size(right, item);
1835 btrfs_set_item_offset(right, item, push_space);
1836 }
1837
1838 btrfs_mark_buffer_dirty(left);
1839 if (right_nritems)
1840 btrfs_mark_buffer_dirty(right);
1841
1842 btrfs_item_key(right, &disk_key, 0);
1843 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1844 if (wret)
1845 ret = wret;
1846
1847 /* then fixup the leaf pointer in the path */
1848 if (path->slots[0] < push_items) {
1849 path->slots[0] += old_left_nritems;
1850 free_extent_buffer(path->nodes[0]);
1851 path->nodes[0] = left;
1852 path->slots[1] -= 1;
1853 } else {
1854 free_extent_buffer(left);
1855 path->slots[0] -= push_items;
1856 }
1857 BUG_ON(path->slots[0] < 0);
1858 return ret;
1859 }
1860
1861 /*
1862 * split the path's leaf in two, making sure there is at least data_size
1863 * available for the resulting leaf level of the path.
1864 *
1865 * returns 0 if all went well and < 0 on failure.
1866 */
1867 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1868 *root, struct btrfs_key *ins_key,
1869 struct btrfs_path *path, int data_size, int extend)
1870 {
1871 u64 root_gen;
1872 struct extent_buffer *l;
1873 u32 nritems;
1874 int mid;
1875 int slot;
1876 struct extent_buffer *right;
1877 int space_needed = data_size + sizeof(struct btrfs_item);
1878 int data_copy_size;
1879 int rt_data_off;
1880 int i;
1881 int ret = 0;
1882 int wret;
1883 int double_split;
1884 int num_doubles = 0;
1885 struct btrfs_disk_key disk_key;
1886
1887 if (extend)
1888 space_needed = data_size;
1889
1890 if (root->ref_cows)
1891 root_gen = trans->transid;
1892 else
1893 root_gen = 0;
1894
1895 /* first try to make some room by pushing left and right */
1896 if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
1897 wret = push_leaf_right(trans, root, path, data_size, 0);
1898 if (wret < 0) {
1899 return wret;
1900 }
1901 if (wret) {
1902 wret = push_leaf_left(trans, root, path, data_size, 0);
1903 if (wret < 0)
1904 return wret;
1905 }
1906 l = path->nodes[0];
1907
1908 /* did the pushes work? */
1909 if (btrfs_leaf_free_space(root, l) >= space_needed)
1910 return 0;
1911 }
1912
1913 if (!path->nodes[1]) {
1914 ret = insert_new_root(trans, root, path, 1);
1915 if (ret)
1916 return ret;
1917 }
1918 again:
1919 double_split = 0;
1920 l = path->nodes[0];
1921 slot = path->slots[0];
1922 nritems = btrfs_header_nritems(l);
1923 mid = (nritems + 1)/ 2;
1924
1925 btrfs_item_key(l, &disk_key, 0);
1926
1927 right = __btrfs_alloc_free_block(trans, root, root->leafsize,
1928 root->root_key.objectid,
1929 root_gen, disk_key.objectid, 0,
1930 l->start, 0);
1931 if (IS_ERR(right)) {
1932 BUG_ON(1);
1933 return PTR_ERR(right);
1934 }
1935
1936 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
1937 btrfs_set_header_bytenr(right, right->start);
1938 btrfs_set_header_generation(right, trans->transid);
1939 btrfs_set_header_owner(right, root->root_key.objectid);
1940 btrfs_set_header_level(right, 0);
1941 write_extent_buffer(right, root->fs_info->fsid,
1942 (unsigned long)btrfs_header_fsid(right),
1943 BTRFS_FSID_SIZE);
1944 if (mid <= slot) {
1945 if (nritems == 1 ||
1946 leaf_space_used(l, mid, nritems - mid) + space_needed >
1947 BTRFS_LEAF_DATA_SIZE(root)) {
1948 if (slot >= nritems) {
1949 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1950 btrfs_set_header_nritems(right, 0);
1951 wret = insert_ptr(trans, root, path,
1952 &disk_key, right->start,
1953 path->slots[1] + 1, 1);
1954 if (wret)
1955 ret = wret;
1956 free_extent_buffer(path->nodes[0]);
1957 path->nodes[0] = right;
1958 path->slots[0] = 0;
1959 path->slots[1] += 1;
1960 return ret;
1961 }
1962 mid = slot;
1963 if (mid != nritems &&
1964 leaf_space_used(l, mid, nritems - mid) +
1965 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
1966 double_split = 1;
1967 }
1968 }
1969 } else {
1970 if (leaf_space_used(l, 0, mid + 1) + space_needed >
1971 BTRFS_LEAF_DATA_SIZE(root)) {
1972 if (!extend && slot == 0) {
1973 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1974 btrfs_set_header_nritems(right, 0);
1975 wret = insert_ptr(trans, root, path,
1976 &disk_key,
1977 right->start,
1978 path->slots[1], 1);
1979 if (wret)
1980 ret = wret;
1981 free_extent_buffer(path->nodes[0]);
1982 path->nodes[0] = right;
1983 path->slots[0] = 0;
1984 if (path->slots[1] == 0) {
1985 wret = fixup_low_keys(trans, root,
1986 path, &disk_key, 1);
1987 if (wret)
1988 ret = wret;
1989 }
1990 return ret;
1991 } else if (extend && slot == 0) {
1992 mid = 1;
1993 } else {
1994 mid = slot;
1995 if (mid != nritems &&
1996 leaf_space_used(l, mid, nritems - mid) +
1997 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
1998 double_split = 1;
1999 }
2000 }
2001 }
2002 }
2003 nritems = nritems - mid;
2004 btrfs_set_header_nritems(right, nritems);
2005 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
2006
2007 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
2008 btrfs_item_nr_offset(mid),
2009 nritems * sizeof(struct btrfs_item));
2010
2011 copy_extent_buffer(right, l,
2012 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
2013 data_copy_size, btrfs_leaf_data(l) +
2014 leaf_data_end(root, l), data_copy_size);
2015
2016 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
2017 btrfs_item_end_nr(l, mid);
2018
2019 for (i = 0; i < nritems; i++) {
2020 struct btrfs_item *item = btrfs_item_nr(right, i);
2021 u32 ioff = btrfs_item_offset(right, item);
2022 btrfs_set_item_offset(right, item, ioff + rt_data_off);
2023 }
2024
2025 btrfs_set_header_nritems(l, mid);
2026 ret = 0;
2027 btrfs_item_key(right, &disk_key, 0);
2028 wret = insert_ptr(trans, root, path, &disk_key, right->start,
2029 path->slots[1] + 1, 1);
2030 if (wret)
2031 ret = wret;
2032
2033 btrfs_mark_buffer_dirty(right);
2034 btrfs_mark_buffer_dirty(l);
2035 BUG_ON(path->slots[0] != slot);
2036
2037 if (mid <= slot) {
2038 free_extent_buffer(path->nodes[0]);
2039 path->nodes[0] = right;
2040 path->slots[0] -= mid;
2041 path->slots[1] += 1;
2042 } else
2043 free_extent_buffer(right);
2044
2045 BUG_ON(path->slots[0] < 0);
2046
2047 if (double_split) {
2048 BUG_ON(num_doubles != 0);
2049 num_doubles++;
2050 goto again;
2051 }
2052 return ret;
2053 }
2054
2055 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
2056 struct btrfs_root *root,
2057 struct btrfs_path *path,
2058 u32 new_size, int from_end)
2059 {
2060 int ret = 0;
2061 int slot;
2062 int slot_orig;
2063 struct extent_buffer *leaf;
2064 struct btrfs_item *item;
2065 u32 nritems;
2066 unsigned int data_end;
2067 unsigned int old_data_start;
2068 unsigned int old_size;
2069 unsigned int size_diff;
2070 int i;
2071
2072 slot_orig = path->slots[0];
2073 leaf = path->nodes[0];
2074 slot = path->slots[0];
2075
2076 old_size = btrfs_item_size_nr(leaf, slot);
2077 if (old_size == new_size)
2078 return 0;
2079
2080 nritems = btrfs_header_nritems(leaf);
2081 data_end = leaf_data_end(root, leaf);
2082
2083 old_data_start = btrfs_item_offset_nr(leaf, slot);
2084
2085 size_diff = old_size - new_size;
2086
2087 BUG_ON(slot < 0);
2088 BUG_ON(slot >= nritems);
2089
2090 /*
2091 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2092 */
2093 /* first correct the data pointers */
2094 for (i = slot; i < nritems; i++) {
2095 u32 ioff;
2096 item = btrfs_item_nr(leaf, i);
2097 ioff = btrfs_item_offset(leaf, item);
2098 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2099 }
2100
2101 /* shift the data */
2102 if (from_end) {
2103 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2104 data_end + size_diff, btrfs_leaf_data(leaf) +
2105 data_end, old_data_start + new_size - data_end);
2106 } else {
2107 struct btrfs_disk_key disk_key;
2108 u64 offset;
2109
2110 btrfs_item_key(leaf, &disk_key, slot);
2111
2112 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2113 unsigned long ptr;
2114 struct btrfs_file_extent_item *fi;
2115
2116 fi = btrfs_item_ptr(leaf, slot,
2117 struct btrfs_file_extent_item);
2118 fi = (struct btrfs_file_extent_item *)(
2119 (unsigned long)fi - size_diff);
2120
2121 if (btrfs_file_extent_type(leaf, fi) ==
2122 BTRFS_FILE_EXTENT_INLINE) {
2123 ptr = btrfs_item_ptr_offset(leaf, slot);
2124 memmove_extent_buffer(leaf, ptr,
2125 (unsigned long)fi,
2126 offsetof(struct btrfs_file_extent_item,
2127 disk_bytenr));
2128 }
2129 }
2130
2131 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2132 data_end + size_diff, btrfs_leaf_data(leaf) +
2133 data_end, old_data_start - data_end);
2134
2135 offset = btrfs_disk_key_offset(&disk_key);
2136 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2137 btrfs_set_item_key(leaf, &disk_key, slot);
2138 if (slot == 0)
2139 fixup_low_keys(trans, root, path, &disk_key, 1);
2140 }
2141
2142 item = btrfs_item_nr(leaf, slot);
2143 btrfs_set_item_size(leaf, item, new_size);
2144 btrfs_mark_buffer_dirty(leaf);
2145
2146 ret = 0;
2147 if (btrfs_leaf_free_space(root, leaf) < 0) {
2148 btrfs_print_leaf(root, leaf);
2149 BUG();
2150 }
2151 return ret;
2152 }
2153
2154 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2155 struct btrfs_root *root, struct btrfs_path *path,
2156 u32 data_size)
2157 {
2158 int ret = 0;
2159 int slot;
2160 int slot_orig;
2161 struct extent_buffer *leaf;
2162 struct btrfs_item *item;
2163 u32 nritems;
2164 unsigned int data_end;
2165 unsigned int old_data;
2166 unsigned int old_size;
2167 int i;
2168
2169 slot_orig = path->slots[0];
2170 leaf = path->nodes[0];
2171
2172 nritems = btrfs_header_nritems(leaf);
2173 data_end = leaf_data_end(root, leaf);
2174
2175 if (btrfs_leaf_free_space(root, leaf) < data_size) {
2176 btrfs_print_leaf(root, leaf);
2177 BUG();
2178 }
2179 slot = path->slots[0];
2180 old_data = btrfs_item_end_nr(leaf, slot);
2181
2182 BUG_ON(slot < 0);
2183 if (slot >= nritems) {
2184 btrfs_print_leaf(root, leaf);
2185 printk("slot %d too large, nritems %d\n", slot, nritems);
2186 BUG_ON(1);
2187 }
2188
2189 /*
2190 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2191 */
2192 /* first correct the data pointers */
2193 for (i = slot; i < nritems; i++) {
2194 u32 ioff;
2195 item = btrfs_item_nr(leaf, i);
2196 ioff = btrfs_item_offset(leaf, item);
2197 btrfs_set_item_offset(leaf, item, ioff - data_size);
2198 }
2199
2200 /* shift the data */
2201 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2202 data_end - data_size, btrfs_leaf_data(leaf) +
2203 data_end, old_data - data_end);
2204
2205 data_end = old_data;
2206 old_size = btrfs_item_size_nr(leaf, slot);
2207 item = btrfs_item_nr(leaf, slot);
2208 btrfs_set_item_size(leaf, item, old_size + data_size);
2209 btrfs_mark_buffer_dirty(leaf);
2210
2211 ret = 0;
2212 if (btrfs_leaf_free_space(root, leaf) < 0) {
2213 btrfs_print_leaf(root, leaf);
2214 BUG();
2215 }
2216 return ret;
2217 }
2218
2219 /*
2220 * Given a key and some data, insert an item into the tree.
2221 * This does all the path init required, making room in the tree if needed.
2222 */
2223 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
2224 struct btrfs_root *root,
2225 struct btrfs_path *path,
2226 struct btrfs_key *cpu_key, u32 *data_size,
2227 int nr)
2228 {
2229 struct extent_buffer *leaf;
2230 struct btrfs_item *item;
2231 int ret = 0;
2232 int slot;
2233 int slot_orig;
2234 int i;
2235 u32 nritems;
2236 u32 total_size = 0;
2237 u32 total_data = 0;
2238 unsigned int data_end;
2239 struct btrfs_disk_key disk_key;
2240
2241 for (i = 0; i < nr; i++) {
2242 total_data += data_size[i];
2243 }
2244
2245 /* create a root if there isn't one */
2246 if (!root->node)
2247 BUG();
2248
2249 total_size = total_data + (nr - 1) * sizeof(struct btrfs_item);
2250 ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
2251 if (ret == 0) {
2252 return -EEXIST;
2253 }
2254 if (ret < 0)
2255 goto out;
2256
2257 slot_orig = path->slots[0];
2258 leaf = path->nodes[0];
2259
2260 nritems = btrfs_header_nritems(leaf);
2261 data_end = leaf_data_end(root, leaf);
2262
2263 if (btrfs_leaf_free_space(root, leaf) <
2264 sizeof(struct btrfs_item) + total_size) {
2265 btrfs_print_leaf(root, leaf);
2266 printk("not enough freespace need %u have %d\n",
2267 total_size, btrfs_leaf_free_space(root, leaf));
2268 BUG();
2269 }
2270
2271 slot = path->slots[0];
2272 BUG_ON(slot < 0);
2273
2274 if (slot != nritems) {
2275 int i;
2276 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2277
2278 if (old_data < data_end) {
2279 btrfs_print_leaf(root, leaf);
2280 printk("slot %d old_data %d data_end %d\n",
2281 slot, old_data, data_end);
2282 BUG_ON(1);
2283 }
2284 /*
2285 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2286 */
2287 /* first correct the data pointers */
2288 for (i = slot; i < nritems; i++) {
2289 u32 ioff;
2290
2291 item = btrfs_item_nr(leaf, i);
2292 ioff = btrfs_item_offset(leaf, item);
2293 btrfs_set_item_offset(leaf, item, ioff - total_data);
2294 }
2295
2296 /* shift the items */
2297 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
2298 btrfs_item_nr_offset(slot),
2299 (nritems - slot) * sizeof(struct btrfs_item));
2300
2301 /* shift the data */
2302 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2303 data_end - total_data, btrfs_leaf_data(leaf) +
2304 data_end, old_data - data_end);
2305 data_end = old_data;
2306 }
2307
2308 /* setup the item for the new data */
2309 for (i = 0; i < nr; i++) {
2310 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
2311 btrfs_set_item_key(leaf, &disk_key, slot + i);
2312 item = btrfs_item_nr(leaf, slot + i);
2313 btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
2314 data_end -= data_size[i];
2315 btrfs_set_item_size(leaf, item, data_size[i]);
2316 }
2317 btrfs_set_header_nritems(leaf, nritems + nr);
2318 btrfs_mark_buffer_dirty(leaf);
2319
2320 ret = 0;
2321 if (slot == 0) {
2322 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2323 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2324 }
2325
2326 if (btrfs_leaf_free_space(root, leaf) < 0) {
2327 btrfs_print_leaf(root, leaf);
2328 BUG();
2329 }
2330
2331 out:
2332 return ret;
2333 }
2334
2335 /*
2336 * Given a key and some data, insert an item into the tree.
2337 * This does all the path init required, making room in the tree if needed.
2338 */
2339 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2340 *root, struct btrfs_key *cpu_key, void *data, u32
2341 data_size)
2342 {
2343 int ret = 0;
2344 struct btrfs_path *path;
2345 struct extent_buffer *leaf;
2346 unsigned long ptr;
2347
2348 path = btrfs_alloc_path();
2349 BUG_ON(!path);
2350 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2351 if (!ret) {
2352 leaf = path->nodes[0];
2353 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2354 write_extent_buffer(leaf, data, ptr, data_size);
2355 btrfs_mark_buffer_dirty(leaf);
2356 }
2357 btrfs_free_path(path);
2358 return ret;
2359 }
2360
2361 /*
2362 * delete the pointer from a given node.
2363 *
2364 * If the delete empties a node, the node is removed from the tree,
2365 * continuing all the way the root if required. The root is converted into
2366 * a leaf if all the nodes are emptied.
2367 */
2368 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2369 struct btrfs_path *path, int level, int slot)
2370 {
2371 struct extent_buffer *parent = path->nodes[level];
2372 u32 nritems;
2373 int ret = 0;
2374 int wret;
2375
2376 nritems = btrfs_header_nritems(parent);
2377 if (slot != nritems -1) {
2378 memmove_extent_buffer(parent,
2379 btrfs_node_key_ptr_offset(slot),
2380 btrfs_node_key_ptr_offset(slot + 1),
2381 sizeof(struct btrfs_key_ptr) *
2382 (nritems - slot - 1));
2383 }
2384 nritems--;
2385 btrfs_set_header_nritems(parent, nritems);
2386 if (nritems == 0 && parent == root->node) {
2387 BUG_ON(btrfs_header_level(root->node) != 1);
2388 /* just turn the root into a leaf and break */
2389 btrfs_set_header_level(root->node, 0);
2390 } else if (slot == 0) {
2391 struct btrfs_disk_key disk_key;
2392
2393 btrfs_node_key(parent, &disk_key, 0);
2394 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2395 if (wret)
2396 ret = wret;
2397 }
2398 btrfs_mark_buffer_dirty(parent);
2399 return ret;
2400 }
2401
2402 /*
2403 * delete the item at the leaf level in path. If that empties
2404 * the leaf, remove it from the tree
2405 */
2406 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2407 struct btrfs_path *path, int slot, int nr)
2408 {
2409 struct extent_buffer *leaf;
2410 struct btrfs_item *item;
2411 int last_off;
2412 int dsize = 0;
2413 int ret = 0;
2414 int wret;
2415 int i;
2416 u32 nritems;
2417
2418 leaf = path->nodes[0];
2419 last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
2420
2421 for (i = 0; i < nr; i++)
2422 dsize += btrfs_item_size_nr(leaf, slot + i);
2423
2424 nritems = btrfs_header_nritems(leaf);
2425
2426 if (slot + nr != nritems) {
2427 int i;
2428 int data_end = leaf_data_end(root, leaf);
2429
2430 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2431 data_end + dsize,
2432 btrfs_leaf_data(leaf) + data_end,
2433 last_off - data_end);
2434
2435 for (i = slot + nr; i < nritems; i++) {
2436 u32 ioff;
2437
2438 item = btrfs_item_nr(leaf, i);
2439 ioff = btrfs_item_offset(leaf, item);
2440 btrfs_set_item_offset(leaf, item, ioff + dsize);
2441 }
2442
2443 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2444 btrfs_item_nr_offset(slot + nr),
2445 sizeof(struct btrfs_item) *
2446 (nritems - slot - nr));
2447 }
2448 btrfs_set_header_nritems(leaf, nritems - nr);
2449 nritems -= nr;
2450
2451 /* delete the leaf if we've emptied it */
2452 if (nritems == 0) {
2453 if (leaf == root->node) {
2454 btrfs_set_header_level(leaf, 0);
2455 } else {
2456 u64 root_gen = btrfs_header_generation(path->nodes[1]);
2457 clean_tree_block(trans, root, leaf);
2458 wait_on_tree_block_writeback(root, leaf);
2459 wret = del_ptr(trans, root, path, 1, path->slots[1]);
2460 if (wret)
2461 ret = wret;
2462 wret = btrfs_free_extent(trans, root,
2463 leaf->start, leaf->len,
2464 btrfs_header_owner(path->nodes[1]),
2465 root_gen, 0, 0, 1);
2466 if (wret)
2467 ret = wret;
2468 }
2469 } else {
2470 int used = leaf_space_used(leaf, 0, nritems);
2471 if (slot == 0) {
2472 struct btrfs_disk_key disk_key;
2473
2474 btrfs_item_key(leaf, &disk_key, 0);
2475 wret = fixup_low_keys(trans, root, path,
2476 &disk_key, 1);
2477 if (wret)
2478 ret = wret;
2479 }
2480
2481 /* delete the leaf if it is mostly empty */
2482 if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
2483 /* push_leaf_left fixes the path.
2484 * make sure the path still points to our leaf
2485 * for possible call to del_ptr below
2486 */
2487 slot = path->slots[1];
2488 extent_buffer_get(leaf);
2489
2490 wret = push_leaf_left(trans, root, path, 1, 1);
2491 if (wret < 0 && wret != -ENOSPC)
2492 ret = wret;
2493
2494 if (path->nodes[0] == leaf &&
2495 btrfs_header_nritems(leaf)) {
2496 wret = push_leaf_right(trans, root, path, 1, 1);
2497 if (wret < 0 && wret != -ENOSPC)
2498 ret = wret;
2499 }
2500
2501 if (btrfs_header_nritems(leaf) == 0) {
2502 u64 root_gen;
2503 u64 bytenr = leaf->start;
2504 u32 blocksize = leaf->len;
2505
2506 root_gen = btrfs_header_generation(
2507 path->nodes[1]);
2508
2509 clean_tree_block(trans, root, leaf);
2510 wait_on_tree_block_writeback(root, leaf);
2511
2512 wret = del_ptr(trans, root, path, 1, slot);
2513 if (wret)
2514 ret = wret;
2515
2516 free_extent_buffer(leaf);
2517 wret = btrfs_free_extent(trans, root, bytenr,
2518 blocksize,
2519 btrfs_header_owner(path->nodes[1]),
2520 root_gen, 0, 0, 1);
2521 if (wret)
2522 ret = wret;
2523 } else {
2524 btrfs_mark_buffer_dirty(leaf);
2525 free_extent_buffer(leaf);
2526 }
2527 } else {
2528 btrfs_mark_buffer_dirty(leaf);
2529 }
2530 }
2531 return ret;
2532 }
2533
2534 /*
2535 * walk up the tree as far as required to find the previous leaf.
2536 * returns 0 if it found something or 1 if there are no lesser leaves.
2537 * returns < 0 on io errors.
2538 */
2539 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
2540 {
2541 u64 bytenr;
2542 int slot;
2543 int level = 1;
2544 struct extent_buffer *c;
2545 struct extent_buffer *next = NULL;
2546
2547 while(level < BTRFS_MAX_LEVEL) {
2548 if (!path->nodes[level])
2549 return 1;
2550
2551 slot = path->slots[level];
2552 c = path->nodes[level];
2553 if (slot == 0) {
2554 level++;
2555 if (level == BTRFS_MAX_LEVEL)
2556 return 1;
2557 continue;
2558 }
2559 slot--;
2560
2561 bytenr = btrfs_node_blockptr(c, slot);
2562 if (next)
2563 free_extent_buffer(next);
2564
2565 next = read_tree_block(root, bytenr,
2566 btrfs_level_size(root, level - 1));
2567 break;
2568 }
2569 path->slots[level] = slot;
2570 while(1) {
2571 level--;
2572 c = path->nodes[level];
2573 free_extent_buffer(c);
2574 slot = btrfs_header_nritems(next);
2575 if (slot != 0)
2576 slot--;
2577 path->nodes[level] = next;
2578 path->slots[level] = slot;
2579 if (!level)
2580 break;
2581 next = read_tree_block(root, btrfs_node_blockptr(next, slot),
2582 btrfs_level_size(root, level - 1));
2583 }
2584 return 0;
2585 }
2586
2587 /*
2588 * walk up the tree as far as required to find the next leaf.
2589 * returns 0 if it found something or 1 if there are no greater leaves.
2590 * returns < 0 on io errors.
2591 */
2592 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2593 {
2594 int slot;
2595 int level = 1;
2596 u64 bytenr;
2597 struct extent_buffer *c;
2598 struct extent_buffer *next = NULL;
2599
2600 while(level < BTRFS_MAX_LEVEL) {
2601 if (!path->nodes[level])
2602 return 1;
2603
2604 slot = path->slots[level] + 1;
2605 c = path->nodes[level];
2606 if (slot >= btrfs_header_nritems(c)) {
2607 level++;
2608 if (level == BTRFS_MAX_LEVEL)
2609 return 1;
2610 continue;
2611 }
2612
2613 bytenr = btrfs_node_blockptr(c, slot);
2614 if (next)
2615 free_extent_buffer(next);
2616
2617 if (path->reada)
2618 reada_for_search(root, path, level, slot, 0);
2619
2620 next = read_tree_block(root, bytenr,
2621 btrfs_level_size(root, level -1));
2622 break;
2623 }
2624 path->slots[level] = slot;
2625 while(1) {
2626 level--;
2627 c = path->nodes[level];
2628 free_extent_buffer(c);
2629 path->nodes[level] = next;
2630 path->slots[level] = 0;
2631 if (!level)
2632 break;
2633 if (path->reada)
2634 reada_for_search(root, path, level, 0, 0);
2635 next = read_tree_block(root, btrfs_node_blockptr(next, 0),
2636 btrfs_level_size(root, level - 1));
2637 }
2638 return 0;
2639 }
2640
2641 int btrfs_previous_item(struct btrfs_root *root,
2642 struct btrfs_path *path, u64 min_objectid,
2643 int type)
2644 {
2645 struct btrfs_key found_key;
2646 struct extent_buffer *leaf;
2647 int ret;
2648
2649 while(1) {
2650 if (path->slots[0] == 0) {
2651 ret = btrfs_prev_leaf(root, path);
2652 if (ret != 0)
2653 return ret;
2654 } else {
2655 path->slots[0]--;
2656 }
2657 leaf = path->nodes[0];
2658 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2659 if (found_key.type == type)
2660 return 0;
2661 }
2662 return 1;
2663 }
2664
(deprecated) Btrfs progs developments and patch integration