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Btrfs: Less aggressive readahead on deletes
[deliverable/linux.git] / fs / btrfs / ctree.c
1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/sched.h>
20 #include "ctree.h"
21 #include "disk-io.h"
22 #include "transaction.h"
23 #include "print-tree.h"
24
25 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
26 *root, struct btrfs_path *path, int level);
27 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
28 *root, struct btrfs_key *ins_key,
29 struct btrfs_path *path, int data_size, int extend);
30 static int push_node_left(struct btrfs_trans_handle *trans,
31 struct btrfs_root *root, struct extent_buffer *dst,
32 struct extent_buffer *src);
33 static int balance_node_right(struct btrfs_trans_handle *trans,
34 struct btrfs_root *root,
35 struct extent_buffer *dst_buf,
36 struct extent_buffer *src_buf);
37 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
38 struct btrfs_path *path, int level, int slot);
39
40 inline void btrfs_init_path(struct btrfs_path *p)
41 {
42 memset(p, 0, sizeof(*p));
43 }
44
45 struct btrfs_path *btrfs_alloc_path(void)
46 {
47 struct btrfs_path *path;
48 path = kmem_cache_alloc(btrfs_path_cachep, GFP_NOFS);
49 if (path) {
50 btrfs_init_path(path);
51 path->reada = 1;
52 }
53 return path;
54 }
55
56 void btrfs_free_path(struct btrfs_path *p)
57 {
58 btrfs_release_path(NULL, p);
59 kmem_cache_free(btrfs_path_cachep, p);
60 }
61
62 void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
63 {
64 int i;
65 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
66 if (!p->nodes[i])
67 break;
68 free_extent_buffer(p->nodes[i]);
69 }
70 memset(p, 0, sizeof(*p));
71 }
72
73 int btrfs_copy_root(struct btrfs_trans_handle *trans,
74 struct btrfs_root *root,
75 struct extent_buffer *buf,
76 struct extent_buffer **cow_ret, u64 new_root_objectid)
77 {
78 struct extent_buffer *cow;
79 u32 nritems;
80 int ret = 0;
81 int level;
82 struct btrfs_key first_key;
83 struct btrfs_root *new_root;
84
85 new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
86 if (!new_root)
87 return -ENOMEM;
88
89 memcpy(new_root, root, sizeof(*new_root));
90 new_root->root_key.objectid = new_root_objectid;
91
92 WARN_ON(root->ref_cows && trans->transid !=
93 root->fs_info->running_transaction->transid);
94 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
95
96 level = btrfs_header_level(buf);
97 nritems = btrfs_header_nritems(buf);
98 if (nritems) {
99 if (level == 0)
100 btrfs_item_key_to_cpu(buf, &first_key, 0);
101 else
102 btrfs_node_key_to_cpu(buf, &first_key, 0);
103 } else {
104 first_key.objectid = 0;
105 }
106 cow = __btrfs_alloc_free_block(trans, new_root, buf->len,
107 new_root_objectid,
108 trans->transid, first_key.objectid,
109 level, buf->start, 0);
110 if (IS_ERR(cow)) {
111 kfree(new_root);
112 return PTR_ERR(cow);
113 }
114
115 copy_extent_buffer(cow, buf, 0, 0, cow->len);
116 btrfs_set_header_bytenr(cow, cow->start);
117 btrfs_set_header_generation(cow, trans->transid);
118 btrfs_set_header_owner(cow, new_root_objectid);
119
120 WARN_ON(btrfs_header_generation(buf) > trans->transid);
121 ret = btrfs_inc_ref(trans, new_root, buf);
122 kfree(new_root);
123
124 if (ret)
125 return ret;
126
127 btrfs_mark_buffer_dirty(cow);
128 *cow_ret = cow;
129 return 0;
130 }
131
132 int __btrfs_cow_block(struct btrfs_trans_handle *trans,
133 struct btrfs_root *root,
134 struct extent_buffer *buf,
135 struct extent_buffer *parent, int parent_slot,
136 struct extent_buffer **cow_ret,
137 u64 search_start, u64 empty_size)
138 {
139 u64 root_gen;
140 struct extent_buffer *cow;
141 u32 nritems;
142 int ret = 0;
143 int different_trans = 0;
144 int level;
145 struct btrfs_key first_key;
146
147 if (root->ref_cows) {
148 root_gen = trans->transid;
149 } else {
150 root_gen = 0;
151 }
152
153 WARN_ON(root->ref_cows && trans->transid !=
154 root->fs_info->running_transaction->transid);
155 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
156
157 level = btrfs_header_level(buf);
158 nritems = btrfs_header_nritems(buf);
159 if (nritems) {
160 if (level == 0)
161 btrfs_item_key_to_cpu(buf, &first_key, 0);
162 else
163 btrfs_node_key_to_cpu(buf, &first_key, 0);
164 } else {
165 first_key.objectid = 0;
166 }
167 cow = __btrfs_alloc_free_block(trans, root, buf->len,
168 root->root_key.objectid,
169 root_gen, first_key.objectid, level,
170 search_start, empty_size);
171 if (IS_ERR(cow))
172 return PTR_ERR(cow);
173
174 copy_extent_buffer(cow, buf, 0, 0, cow->len);
175 btrfs_set_header_bytenr(cow, cow->start);
176 btrfs_set_header_generation(cow, trans->transid);
177 btrfs_set_header_owner(cow, root->root_key.objectid);
178
179 WARN_ON(btrfs_header_generation(buf) > trans->transid);
180 if (btrfs_header_generation(buf) != trans->transid) {
181 different_trans = 1;
182 ret = btrfs_inc_ref(trans, root, buf);
183 if (ret)
184 return ret;
185 } else {
186 clean_tree_block(trans, root, buf);
187 }
188
189 if (buf == root->node) {
190 root_gen = btrfs_header_generation(buf);
191 root->node = cow;
192 extent_buffer_get(cow);
193 if (buf != root->commit_root) {
194 btrfs_free_extent(trans, root, buf->start,
195 buf->len, root->root_key.objectid,
196 root_gen, 0, 0, 1);
197 }
198 free_extent_buffer(buf);
199 } else {
200 root_gen = btrfs_header_generation(parent);
201 btrfs_set_node_blockptr(parent, parent_slot,
202 cow->start);
203 WARN_ON(trans->transid == 0);
204 btrfs_set_node_ptr_generation(parent, parent_slot,
205 trans->transid);
206 btrfs_mark_buffer_dirty(parent);
207 WARN_ON(btrfs_header_generation(parent) != trans->transid);
208 btrfs_free_extent(trans, root, buf->start, buf->len,
209 btrfs_header_owner(parent), root_gen,
210 0, 0, 1);
211 }
212 free_extent_buffer(buf);
213 btrfs_mark_buffer_dirty(cow);
214 *cow_ret = cow;
215 return 0;
216 }
217
218 int btrfs_cow_block(struct btrfs_trans_handle *trans,
219 struct btrfs_root *root, struct extent_buffer *buf,
220 struct extent_buffer *parent, int parent_slot,
221 struct extent_buffer **cow_ret)
222 {
223 u64 search_start;
224 int ret;
225 if (trans->transaction != root->fs_info->running_transaction) {
226 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
227 root->fs_info->running_transaction->transid);
228 WARN_ON(1);
229 }
230 if (trans->transid != root->fs_info->generation) {
231 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
232 root->fs_info->generation);
233 WARN_ON(1);
234 }
235 if (btrfs_header_generation(buf) == trans->transid) {
236 *cow_ret = buf;
237 return 0;
238 }
239
240 search_start = buf->start & ~((u64)BTRFS_BLOCK_GROUP_SIZE - 1);
241 ret = __btrfs_cow_block(trans, root, buf, parent,
242 parent_slot, cow_ret, search_start, 0);
243 return ret;
244 }
245
246 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
247 {
248 if (blocknr < other && other - (blocknr + blocksize) < 32768)
249 return 1;
250 if (blocknr > other && blocknr - (other + blocksize) < 32768)
251 return 1;
252 return 0;
253 }
254
255 /*
256 * compare two keys in a memcmp fashion
257 */
258 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
259 {
260 struct btrfs_key k1;
261
262 btrfs_disk_key_to_cpu(&k1, disk);
263
264 if (k1.objectid > k2->objectid)
265 return 1;
266 if (k1.objectid < k2->objectid)
267 return -1;
268 if (k1.type > k2->type)
269 return 1;
270 if (k1.type < k2->type)
271 return -1;
272 if (k1.offset > k2->offset)
273 return 1;
274 if (k1.offset < k2->offset)
275 return -1;
276 return 0;
277 }
278
279
280 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
281 struct btrfs_root *root, struct extent_buffer *parent,
282 int start_slot, int cache_only, u64 *last_ret,
283 struct btrfs_key *progress)
284 {
285 struct extent_buffer *cur;
286 struct extent_buffer *tmp;
287 u64 blocknr;
288 u64 search_start = *last_ret;
289 u64 last_block = 0;
290 u64 other;
291 u32 parent_nritems;
292 int end_slot;
293 int i;
294 int err = 0;
295 int parent_level;
296 int uptodate;
297 u32 blocksize;
298 int progress_passed = 0;
299 struct btrfs_disk_key disk_key;
300
301 parent_level = btrfs_header_level(parent);
302 if (cache_only && parent_level != 1)
303 return 0;
304
305 if (trans->transaction != root->fs_info->running_transaction) {
306 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
307 root->fs_info->running_transaction->transid);
308 WARN_ON(1);
309 }
310 if (trans->transid != root->fs_info->generation) {
311 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
312 root->fs_info->generation);
313 WARN_ON(1);
314 }
315
316 parent_nritems = btrfs_header_nritems(parent);
317 blocksize = btrfs_level_size(root, parent_level - 1);
318 end_slot = parent_nritems;
319
320 if (parent_nritems == 1)
321 return 0;
322
323 for (i = start_slot; i < end_slot; i++) {
324 int close = 1;
325
326 if (!parent->map_token) {
327 map_extent_buffer(parent,
328 btrfs_node_key_ptr_offset(i),
329 sizeof(struct btrfs_key_ptr),
330 &parent->map_token, &parent->kaddr,
331 &parent->map_start, &parent->map_len,
332 KM_USER1);
333 }
334 btrfs_node_key(parent, &disk_key, i);
335 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
336 continue;
337
338 progress_passed = 1;
339 blocknr = btrfs_node_blockptr(parent, i);
340 if (last_block == 0)
341 last_block = blocknr;
342
343 if (i > 0) {
344 other = btrfs_node_blockptr(parent, i - 1);
345 close = close_blocks(blocknr, other, blocksize);
346 }
347 if (close && i < end_slot - 2) {
348 other = btrfs_node_blockptr(parent, i + 1);
349 close = close_blocks(blocknr, other, blocksize);
350 }
351 if (close) {
352 last_block = blocknr;
353 continue;
354 }
355 if (parent->map_token) {
356 unmap_extent_buffer(parent, parent->map_token,
357 KM_USER1);
358 parent->map_token = NULL;
359 }
360
361 cur = btrfs_find_tree_block(root, blocknr, blocksize);
362 if (cur)
363 uptodate = btrfs_buffer_uptodate(cur);
364 else
365 uptodate = 0;
366 if (!cur || !uptodate) {
367 if (cache_only) {
368 free_extent_buffer(cur);
369 continue;
370 }
371 if (!cur) {
372 cur = read_tree_block(root, blocknr,
373 blocksize);
374 } else if (!uptodate) {
375 btrfs_read_buffer(cur);
376 }
377 }
378 if (search_start == 0)
379 search_start = last_block;
380
381 err = __btrfs_cow_block(trans, root, cur, parent, i,
382 &tmp, search_start,
383 min(16 * blocksize,
384 (end_slot - i) * blocksize));
385 if (err) {
386 free_extent_buffer(cur);
387 break;
388 }
389 search_start = tmp->start;
390 last_block = tmp->start;
391 *last_ret = search_start;
392 if (parent_level == 1)
393 btrfs_clear_buffer_defrag(tmp);
394 free_extent_buffer(tmp);
395 }
396 if (parent->map_token) {
397 unmap_extent_buffer(parent, parent->map_token,
398 KM_USER1);
399 parent->map_token = NULL;
400 }
401 return err;
402 }
403
404 /*
405 * The leaf data grows from end-to-front in the node.
406 * this returns the address of the start of the last item,
407 * which is the stop of the leaf data stack
408 */
409 static inline unsigned int leaf_data_end(struct btrfs_root *root,
410 struct extent_buffer *leaf)
411 {
412 u32 nr = btrfs_header_nritems(leaf);
413 if (nr == 0)
414 return BTRFS_LEAF_DATA_SIZE(root);
415 return btrfs_item_offset_nr(leaf, nr - 1);
416 }
417
418 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
419 int level)
420 {
421 struct extent_buffer *parent = NULL;
422 struct extent_buffer *node = path->nodes[level];
423 struct btrfs_disk_key parent_key;
424 struct btrfs_disk_key node_key;
425 int parent_slot;
426 int slot;
427 struct btrfs_key cpukey;
428 u32 nritems = btrfs_header_nritems(node);
429
430 if (path->nodes[level + 1])
431 parent = path->nodes[level + 1];
432
433 slot = path->slots[level];
434 BUG_ON(nritems == 0);
435 if (parent) {
436 parent_slot = path->slots[level + 1];
437 btrfs_node_key(parent, &parent_key, parent_slot);
438 btrfs_node_key(node, &node_key, 0);
439 BUG_ON(memcmp(&parent_key, &node_key,
440 sizeof(struct btrfs_disk_key)));
441 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
442 btrfs_header_bytenr(node));
443 }
444 BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
445 if (slot != 0) {
446 btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
447 btrfs_node_key(node, &node_key, slot);
448 BUG_ON(comp_keys(&node_key, &cpukey) <= 0);
449 }
450 if (slot < nritems - 1) {
451 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
452 btrfs_node_key(node, &node_key, slot);
453 BUG_ON(comp_keys(&node_key, &cpukey) >= 0);
454 }
455 return 0;
456 }
457
458 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
459 int level)
460 {
461 struct extent_buffer *leaf = path->nodes[level];
462 struct extent_buffer *parent = NULL;
463 int parent_slot;
464 struct btrfs_key cpukey;
465 struct btrfs_disk_key parent_key;
466 struct btrfs_disk_key leaf_key;
467 int slot = path->slots[0];
468
469 u32 nritems = btrfs_header_nritems(leaf);
470
471 if (path->nodes[level + 1])
472 parent = path->nodes[level + 1];
473
474 if (nritems == 0)
475 return 0;
476
477 if (parent) {
478 parent_slot = path->slots[level + 1];
479 btrfs_node_key(parent, &parent_key, parent_slot);
480 btrfs_item_key(leaf, &leaf_key, 0);
481
482 BUG_ON(memcmp(&parent_key, &leaf_key,
483 sizeof(struct btrfs_disk_key)));
484 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
485 btrfs_header_bytenr(leaf));
486 }
487 #if 0
488 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
489 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
490 btrfs_item_key(leaf, &leaf_key, i);
491 if (comp_keys(&leaf_key, &cpukey) >= 0) {
492 btrfs_print_leaf(root, leaf);
493 printk("slot %d offset bad key\n", i);
494 BUG_ON(1);
495 }
496 if (btrfs_item_offset_nr(leaf, i) !=
497 btrfs_item_end_nr(leaf, i + 1)) {
498 btrfs_print_leaf(root, leaf);
499 printk("slot %d offset bad\n", i);
500 BUG_ON(1);
501 }
502 if (i == 0) {
503 if (btrfs_item_offset_nr(leaf, i) +
504 btrfs_item_size_nr(leaf, i) !=
505 BTRFS_LEAF_DATA_SIZE(root)) {
506 btrfs_print_leaf(root, leaf);
507 printk("slot %d first offset bad\n", i);
508 BUG_ON(1);
509 }
510 }
511 }
512 if (nritems > 0) {
513 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
514 btrfs_print_leaf(root, leaf);
515 printk("slot %d bad size \n", nritems - 1);
516 BUG_ON(1);
517 }
518 }
519 #endif
520 if (slot != 0 && slot < nritems - 1) {
521 btrfs_item_key(leaf, &leaf_key, slot);
522 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
523 if (comp_keys(&leaf_key, &cpukey) <= 0) {
524 btrfs_print_leaf(root, leaf);
525 printk("slot %d offset bad key\n", slot);
526 BUG_ON(1);
527 }
528 if (btrfs_item_offset_nr(leaf, slot - 1) !=
529 btrfs_item_end_nr(leaf, slot)) {
530 btrfs_print_leaf(root, leaf);
531 printk("slot %d offset bad\n", slot);
532 BUG_ON(1);
533 }
534 }
535 if (slot < nritems - 1) {
536 btrfs_item_key(leaf, &leaf_key, slot);
537 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
538 BUG_ON(comp_keys(&leaf_key, &cpukey) >= 0);
539 if (btrfs_item_offset_nr(leaf, slot) !=
540 btrfs_item_end_nr(leaf, slot + 1)) {
541 btrfs_print_leaf(root, leaf);
542 printk("slot %d offset bad\n", slot);
543 BUG_ON(1);
544 }
545 }
546 BUG_ON(btrfs_item_offset_nr(leaf, 0) +
547 btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
548 return 0;
549 }
550
551 static int check_block(struct btrfs_root *root, struct btrfs_path *path,
552 int level)
553 {
554 return 0;
555 #if 0
556 struct extent_buffer *buf = path->nodes[level];
557
558 if (memcmp_extent_buffer(buf, root->fs_info->fsid,
559 (unsigned long)btrfs_header_fsid(buf),
560 BTRFS_FSID_SIZE)) {
561 printk("warning bad block %Lu\n", buf->start);
562 return 1;
563 }
564 #endif
565 if (level == 0)
566 return check_leaf(root, path, level);
567 return check_node(root, path, level);
568 }
569
570 /*
571 * search for key in the extent_buffer. The items start at offset p,
572 * and they are item_size apart. There are 'max' items in p.
573 *
574 * the slot in the array is returned via slot, and it points to
575 * the place where you would insert key if it is not found in
576 * the array.
577 *
578 * slot may point to max if the key is bigger than all of the keys
579 */
580 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
581 int item_size, struct btrfs_key *key,
582 int max, int *slot)
583 {
584 int low = 0;
585 int high = max;
586 int mid;
587 int ret;
588 struct btrfs_disk_key *tmp = NULL;
589 struct btrfs_disk_key unaligned;
590 unsigned long offset;
591 char *map_token = NULL;
592 char *kaddr = NULL;
593 unsigned long map_start = 0;
594 unsigned long map_len = 0;
595 int err;
596
597 while(low < high) {
598 mid = (low + high) / 2;
599 offset = p + mid * item_size;
600
601 if (!map_token || offset < map_start ||
602 (offset + sizeof(struct btrfs_disk_key)) >
603 map_start + map_len) {
604 if (map_token) {
605 unmap_extent_buffer(eb, map_token, KM_USER0);
606 map_token = NULL;
607 }
608 err = map_extent_buffer(eb, offset,
609 sizeof(struct btrfs_disk_key),
610 &map_token, &kaddr,
611 &map_start, &map_len, KM_USER0);
612
613 if (!err) {
614 tmp = (struct btrfs_disk_key *)(kaddr + offset -
615 map_start);
616 } else {
617 read_extent_buffer(eb, &unaligned,
618 offset, sizeof(unaligned));
619 tmp = &unaligned;
620 }
621
622 } else {
623 tmp = (struct btrfs_disk_key *)(kaddr + offset -
624 map_start);
625 }
626 ret = comp_keys(tmp, key);
627
628 if (ret < 0)
629 low = mid + 1;
630 else if (ret > 0)
631 high = mid;
632 else {
633 *slot = mid;
634 if (map_token)
635 unmap_extent_buffer(eb, map_token, KM_USER0);
636 return 0;
637 }
638 }
639 *slot = low;
640 if (map_token)
641 unmap_extent_buffer(eb, map_token, KM_USER0);
642 return 1;
643 }
644
645 /*
646 * simple bin_search frontend that does the right thing for
647 * leaves vs nodes
648 */
649 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
650 int level, int *slot)
651 {
652 if (level == 0) {
653 return generic_bin_search(eb,
654 offsetof(struct btrfs_leaf, items),
655 sizeof(struct btrfs_item),
656 key, btrfs_header_nritems(eb),
657 slot);
658 } else {
659 return generic_bin_search(eb,
660 offsetof(struct btrfs_node, ptrs),
661 sizeof(struct btrfs_key_ptr),
662 key, btrfs_header_nritems(eb),
663 slot);
664 }
665 return -1;
666 }
667
668 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
669 struct extent_buffer *parent, int slot)
670 {
671 if (slot < 0)
672 return NULL;
673 if (slot >= btrfs_header_nritems(parent))
674 return NULL;
675 return read_tree_block(root, btrfs_node_blockptr(parent, slot),
676 btrfs_level_size(root, btrfs_header_level(parent) - 1));
677 }
678
679 static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
680 *root, struct btrfs_path *path, int level)
681 {
682 struct extent_buffer *right = NULL;
683 struct extent_buffer *mid;
684 struct extent_buffer *left = NULL;
685 struct extent_buffer *parent = NULL;
686 int ret = 0;
687 int wret;
688 int pslot;
689 int orig_slot = path->slots[level];
690 int err_on_enospc = 0;
691 u64 orig_ptr;
692
693 if (level == 0)
694 return 0;
695
696 mid = path->nodes[level];
697 WARN_ON(btrfs_header_generation(mid) != trans->transid);
698
699 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
700
701 if (level < BTRFS_MAX_LEVEL - 1)
702 parent = path->nodes[level + 1];
703 pslot = path->slots[level + 1];
704
705 /*
706 * deal with the case where there is only one pointer in the root
707 * by promoting the node below to a root
708 */
709 if (!parent) {
710 struct extent_buffer *child;
711
712 if (btrfs_header_nritems(mid) != 1)
713 return 0;
714
715 /* promote the child to a root */
716 child = read_node_slot(root, mid, 0);
717 BUG_ON(!child);
718 root->node = child;
719 path->nodes[level] = NULL;
720 clean_tree_block(trans, root, mid);
721 wait_on_tree_block_writeback(root, mid);
722 /* once for the path */
723 free_extent_buffer(mid);
724 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
725 root->root_key.objectid,
726 btrfs_header_generation(mid), 0, 0, 1);
727 /* once for the root ptr */
728 free_extent_buffer(mid);
729 return ret;
730 }
731 if (btrfs_header_nritems(mid) >
732 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
733 return 0;
734
735 if (btrfs_header_nritems(mid) < 2)
736 err_on_enospc = 1;
737
738 left = read_node_slot(root, parent, pslot - 1);
739 if (left) {
740 wret = btrfs_cow_block(trans, root, left,
741 parent, pslot - 1, &left);
742 if (wret) {
743 ret = wret;
744 goto enospc;
745 }
746 }
747 right = read_node_slot(root, parent, pslot + 1);
748 if (right) {
749 wret = btrfs_cow_block(trans, root, right,
750 parent, pslot + 1, &right);
751 if (wret) {
752 ret = wret;
753 goto enospc;
754 }
755 }
756
757 /* first, try to make some room in the middle buffer */
758 if (left) {
759 orig_slot += btrfs_header_nritems(left);
760 wret = push_node_left(trans, root, left, mid);
761 if (wret < 0)
762 ret = wret;
763 if (btrfs_header_nritems(mid) < 2)
764 err_on_enospc = 1;
765 }
766
767 /*
768 * then try to empty the right most buffer into the middle
769 */
770 if (right) {
771 wret = push_node_left(trans, root, mid, right);
772 if (wret < 0 && wret != -ENOSPC)
773 ret = wret;
774 if (btrfs_header_nritems(right) == 0) {
775 u64 bytenr = right->start;
776 u64 generation = btrfs_header_generation(parent);
777 u32 blocksize = right->len;
778
779 clean_tree_block(trans, root, right);
780 wait_on_tree_block_writeback(root, right);
781 free_extent_buffer(right);
782 right = NULL;
783 wret = del_ptr(trans, root, path, level + 1, pslot +
784 1);
785 if (wret)
786 ret = wret;
787 wret = btrfs_free_extent(trans, root, bytenr,
788 blocksize,
789 btrfs_header_owner(parent),
790 generation, 0, 0, 1);
791 if (wret)
792 ret = wret;
793 } else {
794 struct btrfs_disk_key right_key;
795 btrfs_node_key(right, &right_key, 0);
796 btrfs_set_node_key(parent, &right_key, pslot + 1);
797 btrfs_mark_buffer_dirty(parent);
798 }
799 }
800 if (btrfs_header_nritems(mid) == 1) {
801 /*
802 * we're not allowed to leave a node with one item in the
803 * tree during a delete. A deletion from lower in the tree
804 * could try to delete the only pointer in this node.
805 * So, pull some keys from the left.
806 * There has to be a left pointer at this point because
807 * otherwise we would have pulled some pointers from the
808 * right
809 */
810 BUG_ON(!left);
811 wret = balance_node_right(trans, root, mid, left);
812 if (wret < 0) {
813 ret = wret;
814 goto enospc;
815 }
816 BUG_ON(wret == 1);
817 }
818 if (btrfs_header_nritems(mid) == 0) {
819 /* we've managed to empty the middle node, drop it */
820 u64 root_gen = btrfs_header_generation(parent);
821 u64 bytenr = mid->start;
822 u32 blocksize = mid->len;
823 clean_tree_block(trans, root, mid);
824 wait_on_tree_block_writeback(root, mid);
825 free_extent_buffer(mid);
826 mid = NULL;
827 wret = del_ptr(trans, root, path, level + 1, pslot);
828 if (wret)
829 ret = wret;
830 wret = btrfs_free_extent(trans, root, bytenr, blocksize,
831 btrfs_header_owner(parent),
832 root_gen, 0, 0, 1);
833 if (wret)
834 ret = wret;
835 } else {
836 /* update the parent key to reflect our changes */
837 struct btrfs_disk_key mid_key;
838 btrfs_node_key(mid, &mid_key, 0);
839 btrfs_set_node_key(parent, &mid_key, pslot);
840 btrfs_mark_buffer_dirty(parent);
841 }
842
843 /* update the path */
844 if (left) {
845 if (btrfs_header_nritems(left) > orig_slot) {
846 extent_buffer_get(left);
847 path->nodes[level] = left;
848 path->slots[level + 1] -= 1;
849 path->slots[level] = orig_slot;
850 if (mid)
851 free_extent_buffer(mid);
852 } else {
853 orig_slot -= btrfs_header_nritems(left);
854 path->slots[level] = orig_slot;
855 }
856 }
857 /* double check we haven't messed things up */
858 check_block(root, path, level);
859 if (orig_ptr !=
860 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
861 BUG();
862 enospc:
863 if (right)
864 free_extent_buffer(right);
865 if (left)
866 free_extent_buffer(left);
867 return ret;
868 }
869
870 /* returns zero if the push worked, non-zero otherwise */
871 static int push_nodes_for_insert(struct btrfs_trans_handle *trans,
872 struct btrfs_root *root,
873 struct btrfs_path *path, int level)
874 {
875 struct extent_buffer *right = NULL;
876 struct extent_buffer *mid;
877 struct extent_buffer *left = NULL;
878 struct extent_buffer *parent = NULL;
879 int ret = 0;
880 int wret;
881 int pslot;
882 int orig_slot = path->slots[level];
883 u64 orig_ptr;
884
885 if (level == 0)
886 return 1;
887
888 mid = path->nodes[level];
889 WARN_ON(btrfs_header_generation(mid) != trans->transid);
890 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
891
892 if (level < BTRFS_MAX_LEVEL - 1)
893 parent = path->nodes[level + 1];
894 pslot = path->slots[level + 1];
895
896 if (!parent)
897 return 1;
898
899 left = read_node_slot(root, parent, pslot - 1);
900
901 /* first, try to make some room in the middle buffer */
902 if (left) {
903 u32 left_nr;
904 left_nr = btrfs_header_nritems(left);
905 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
906 wret = 1;
907 } else {
908 ret = btrfs_cow_block(trans, root, left, parent,
909 pslot - 1, &left);
910 if (ret)
911 wret = 1;
912 else {
913 wret = push_node_left(trans, root,
914 left, mid);
915 }
916 }
917 if (wret < 0)
918 ret = wret;
919 if (wret == 0) {
920 struct btrfs_disk_key disk_key;
921 orig_slot += left_nr;
922 btrfs_node_key(mid, &disk_key, 0);
923 btrfs_set_node_key(parent, &disk_key, pslot);
924 btrfs_mark_buffer_dirty(parent);
925 if (btrfs_header_nritems(left) > orig_slot) {
926 path->nodes[level] = left;
927 path->slots[level + 1] -= 1;
928 path->slots[level] = orig_slot;
929 free_extent_buffer(mid);
930 } else {
931 orig_slot -=
932 btrfs_header_nritems(left);
933 path->slots[level] = orig_slot;
934 free_extent_buffer(left);
935 }
936 return 0;
937 }
938 free_extent_buffer(left);
939 }
940 right= read_node_slot(root, parent, pslot + 1);
941
942 /*
943 * then try to empty the right most buffer into the middle
944 */
945 if (right) {
946 u32 right_nr;
947 right_nr = btrfs_header_nritems(right);
948 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
949 wret = 1;
950 } else {
951 ret = btrfs_cow_block(trans, root, right,
952 parent, pslot + 1,
953 &right);
954 if (ret)
955 wret = 1;
956 else {
957 wret = balance_node_right(trans, root,
958 right, mid);
959 }
960 }
961 if (wret < 0)
962 ret = wret;
963 if (wret == 0) {
964 struct btrfs_disk_key disk_key;
965
966 btrfs_node_key(right, &disk_key, 0);
967 btrfs_set_node_key(parent, &disk_key, pslot + 1);
968 btrfs_mark_buffer_dirty(parent);
969
970 if (btrfs_header_nritems(mid) <= orig_slot) {
971 path->nodes[level] = right;
972 path->slots[level + 1] += 1;
973 path->slots[level] = orig_slot -
974 btrfs_header_nritems(mid);
975 free_extent_buffer(mid);
976 } else {
977 free_extent_buffer(right);
978 }
979 return 0;
980 }
981 free_extent_buffer(right);
982 }
983 return 1;
984 }
985
986 /*
987 * readahead one full node of leaves
988 */
989 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
990 int level, int slot, u64 objectid)
991 {
992 struct extent_buffer *node;
993 struct btrfs_disk_key disk_key;
994 u32 nritems;
995 u64 search;
996 u64 lowest_read;
997 u64 highest_read;
998 u64 nread = 0;
999 int direction = path->reada;
1000 struct extent_buffer *eb;
1001 u32 nr;
1002 u32 blocksize;
1003 u32 nscan = 0;
1004
1005 if (level != 1)
1006 return;
1007
1008 if (!path->nodes[level])
1009 return;
1010
1011 node = path->nodes[level];
1012 search = btrfs_node_blockptr(node, slot);
1013 blocksize = btrfs_level_size(root, level - 1);
1014 eb = btrfs_find_tree_block(root, search, blocksize);
1015 if (eb) {
1016 free_extent_buffer(eb);
1017 return;
1018 }
1019
1020 highest_read = search;
1021 lowest_read = search;
1022
1023 nritems = btrfs_header_nritems(node);
1024 nr = slot;
1025 while(1) {
1026 if (direction < 0) {
1027 if (nr == 0)
1028 break;
1029 nr--;
1030 } else if (direction > 0) {
1031 nr++;
1032 if (nr >= nritems)
1033 break;
1034 }
1035 if (path->reada < 0 && objectid) {
1036 btrfs_node_key(node, &disk_key, nr);
1037 if (btrfs_disk_key_objectid(&disk_key) != objectid)
1038 break;
1039 }
1040 search = btrfs_node_blockptr(node, nr);
1041 if ((search >= lowest_read && search <= highest_read) ||
1042 (search < lowest_read && lowest_read - search <= 32768) ||
1043 (search > highest_read && search - highest_read <= 32768)) {
1044 readahead_tree_block(root, search, blocksize);
1045 nread += blocksize;
1046 }
1047 nscan++;
1048 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
1049 break;
1050 if(nread > (1024 * 1024) || nscan > 128)
1051 break;
1052
1053 if (search < lowest_read)
1054 lowest_read = search;
1055 if (search > highest_read)
1056 highest_read = search;
1057 }
1058 }
1059 /*
1060 * look for key in the tree. path is filled in with nodes along the way
1061 * if key is found, we return zero and you can find the item in the leaf
1062 * level of the path (level 0)
1063 *
1064 * If the key isn't found, the path points to the slot where it should
1065 * be inserted, and 1 is returned. If there are other errors during the
1066 * search a negative error number is returned.
1067 *
1068 * if ins_len > 0, nodes and leaves will be split as we walk down the
1069 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
1070 * possible)
1071 */
1072 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
1073 *root, struct btrfs_key *key, struct btrfs_path *p, int
1074 ins_len, int cow)
1075 {
1076 struct extent_buffer *b;
1077 u64 bytenr;
1078 u64 ptr_gen;
1079 int slot;
1080 int ret;
1081 int level;
1082 int should_reada = p->reada;
1083 u8 lowest_level = 0;
1084
1085 lowest_level = p->lowest_level;
1086 WARN_ON(lowest_level && ins_len);
1087 WARN_ON(p->nodes[0] != NULL);
1088 WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
1089 again:
1090 b = root->node;
1091 extent_buffer_get(b);
1092 while (b) {
1093 level = btrfs_header_level(b);
1094 if (cow) {
1095 int wret;
1096 wret = btrfs_cow_block(trans, root, b,
1097 p->nodes[level + 1],
1098 p->slots[level + 1],
1099 &b);
1100 if (wret) {
1101 free_extent_buffer(b);
1102 return wret;
1103 }
1104 }
1105 BUG_ON(!cow && ins_len);
1106 if (level != btrfs_header_level(b))
1107 WARN_ON(1);
1108 level = btrfs_header_level(b);
1109 p->nodes[level] = b;
1110 ret = check_block(root, p, level);
1111 if (ret)
1112 return -1;
1113 ret = bin_search(b, key, level, &slot);
1114 if (level != 0) {
1115 if (ret && slot > 0)
1116 slot -= 1;
1117 p->slots[level] = slot;
1118 if (ins_len > 0 && btrfs_header_nritems(b) >=
1119 BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1120 int sret = split_node(trans, root, p, level);
1121 BUG_ON(sret > 0);
1122 if (sret)
1123 return sret;
1124 b = p->nodes[level];
1125 slot = p->slots[level];
1126 } else if (ins_len < 0) {
1127 int sret = balance_level(trans, root, p,
1128 level);
1129 if (sret)
1130 return sret;
1131 b = p->nodes[level];
1132 if (!b) {
1133 btrfs_release_path(NULL, p);
1134 goto again;
1135 }
1136 slot = p->slots[level];
1137 BUG_ON(btrfs_header_nritems(b) == 1);
1138 }
1139 /* this is only true while dropping a snapshot */
1140 if (level == lowest_level)
1141 break;
1142 bytenr = btrfs_node_blockptr(b, slot);
1143 ptr_gen = btrfs_node_ptr_generation(b, slot);
1144 if (should_reada)
1145 reada_for_search(root, p, level, slot,
1146 key->objectid);
1147 b = read_tree_block(root, bytenr,
1148 btrfs_level_size(root, level - 1));
1149 if (ptr_gen != btrfs_header_generation(b)) {
1150 printk("block %llu bad gen wanted %llu "
1151 "found %llu\n",
1152 (unsigned long long)b->start,
1153 (unsigned long long)ptr_gen,
1154 (unsigned long long)btrfs_header_generation(b));
1155 }
1156 } else {
1157 p->slots[level] = slot;
1158 if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1159 sizeof(struct btrfs_item) + ins_len) {
1160 int sret = split_leaf(trans, root, key,
1161 p, ins_len, ret == 0);
1162 BUG_ON(sret > 0);
1163 if (sret)
1164 return sret;
1165 }
1166 return ret;
1167 }
1168 }
1169 return 1;
1170 }
1171
1172 /*
1173 * adjust the pointers going up the tree, starting at level
1174 * making sure the right key of each node is points to 'key'.
1175 * This is used after shifting pointers to the left, so it stops
1176 * fixing up pointers when a given leaf/node is not in slot 0 of the
1177 * higher levels
1178 *
1179 * If this fails to write a tree block, it returns -1, but continues
1180 * fixing up the blocks in ram so the tree is consistent.
1181 */
1182 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1183 struct btrfs_root *root, struct btrfs_path *path,
1184 struct btrfs_disk_key *key, int level)
1185 {
1186 int i;
1187 int ret = 0;
1188 struct extent_buffer *t;
1189
1190 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1191 int tslot = path->slots[i];
1192 if (!path->nodes[i])
1193 break;
1194 t = path->nodes[i];
1195 btrfs_set_node_key(t, key, tslot);
1196 btrfs_mark_buffer_dirty(path->nodes[i]);
1197 if (tslot != 0)
1198 break;
1199 }
1200 return ret;
1201 }
1202
1203 /*
1204 * try to push data from one node into the next node left in the
1205 * tree.
1206 *
1207 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1208 * error, and > 0 if there was no room in the left hand block.
1209 */
1210 static int push_node_left(struct btrfs_trans_handle *trans, struct btrfs_root
1211 *root, struct extent_buffer *dst,
1212 struct extent_buffer *src)
1213 {
1214 int push_items = 0;
1215 int src_nritems;
1216 int dst_nritems;
1217 int ret = 0;
1218
1219 src_nritems = btrfs_header_nritems(src);
1220 dst_nritems = btrfs_header_nritems(dst);
1221 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1222 WARN_ON(btrfs_header_generation(src) != trans->transid);
1223 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1224
1225 if (push_items <= 0) {
1226 return 1;
1227 }
1228
1229 if (src_nritems < push_items)
1230 push_items = src_nritems;
1231
1232 copy_extent_buffer(dst, src,
1233 btrfs_node_key_ptr_offset(dst_nritems),
1234 btrfs_node_key_ptr_offset(0),
1235 push_items * sizeof(struct btrfs_key_ptr));
1236
1237 if (push_items < src_nritems) {
1238 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1239 btrfs_node_key_ptr_offset(push_items),
1240 (src_nritems - push_items) *
1241 sizeof(struct btrfs_key_ptr));
1242 }
1243 btrfs_set_header_nritems(src, src_nritems - push_items);
1244 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1245 btrfs_mark_buffer_dirty(src);
1246 btrfs_mark_buffer_dirty(dst);
1247 return ret;
1248 }
1249
1250 /*
1251 * try to push data from one node into the next node right in the
1252 * tree.
1253 *
1254 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1255 * error, and > 0 if there was no room in the right hand block.
1256 *
1257 * this will only push up to 1/2 the contents of the left node over
1258 */
1259 static int balance_node_right(struct btrfs_trans_handle *trans,
1260 struct btrfs_root *root,
1261 struct extent_buffer *dst,
1262 struct extent_buffer *src)
1263 {
1264 int push_items = 0;
1265 int max_push;
1266 int src_nritems;
1267 int dst_nritems;
1268 int ret = 0;
1269
1270 WARN_ON(btrfs_header_generation(src) != trans->transid);
1271 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1272
1273 src_nritems = btrfs_header_nritems(src);
1274 dst_nritems = btrfs_header_nritems(dst);
1275 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1276 if (push_items <= 0)
1277 return 1;
1278
1279 max_push = src_nritems / 2 + 1;
1280 /* don't try to empty the node */
1281 if (max_push >= src_nritems)
1282 return 1;
1283
1284 if (max_push < push_items)
1285 push_items = max_push;
1286
1287 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1288 btrfs_node_key_ptr_offset(0),
1289 (dst_nritems) *
1290 sizeof(struct btrfs_key_ptr));
1291
1292 copy_extent_buffer(dst, src,
1293 btrfs_node_key_ptr_offset(0),
1294 btrfs_node_key_ptr_offset(src_nritems - push_items),
1295 push_items * sizeof(struct btrfs_key_ptr));
1296
1297 btrfs_set_header_nritems(src, src_nritems - push_items);
1298 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1299
1300 btrfs_mark_buffer_dirty(src);
1301 btrfs_mark_buffer_dirty(dst);
1302 return ret;
1303 }
1304
1305 /*
1306 * helper function to insert a new root level in the tree.
1307 * A new node is allocated, and a single item is inserted to
1308 * point to the existing root
1309 *
1310 * returns zero on success or < 0 on failure.
1311 */
1312 static int insert_new_root(struct btrfs_trans_handle *trans,
1313 struct btrfs_root *root,
1314 struct btrfs_path *path, int level)
1315 {
1316 u64 root_gen;
1317 u64 lower_gen;
1318 struct extent_buffer *lower;
1319 struct extent_buffer *c;
1320 struct btrfs_disk_key lower_key;
1321
1322 BUG_ON(path->nodes[level]);
1323 BUG_ON(path->nodes[level-1] != root->node);
1324
1325 if (root->ref_cows)
1326 root_gen = trans->transid;
1327 else
1328 root_gen = 0;
1329
1330 lower = path->nodes[level-1];
1331 if (level == 1)
1332 btrfs_item_key(lower, &lower_key, 0);
1333 else
1334 btrfs_node_key(lower, &lower_key, 0);
1335
1336 c = __btrfs_alloc_free_block(trans, root, root->nodesize,
1337 root->root_key.objectid,
1338 root_gen, lower_key.objectid, level,
1339 root->node->start, 0);
1340 if (IS_ERR(c))
1341 return PTR_ERR(c);
1342 memset_extent_buffer(c, 0, 0, root->nodesize);
1343 btrfs_set_header_nritems(c, 1);
1344 btrfs_set_header_level(c, level);
1345 btrfs_set_header_bytenr(c, c->start);
1346 btrfs_set_header_generation(c, trans->transid);
1347 btrfs_set_header_owner(c, root->root_key.objectid);
1348
1349 write_extent_buffer(c, root->fs_info->fsid,
1350 (unsigned long)btrfs_header_fsid(c),
1351 BTRFS_FSID_SIZE);
1352 btrfs_set_node_key(c, &lower_key, 0);
1353 btrfs_set_node_blockptr(c, 0, lower->start);
1354 lower_gen = btrfs_header_generation(lower);
1355 WARN_ON(lower_gen == 0);
1356
1357 btrfs_set_node_ptr_generation(c, 0, lower_gen);
1358
1359 btrfs_mark_buffer_dirty(c);
1360
1361 /* the super has an extra ref to root->node */
1362 free_extent_buffer(root->node);
1363 root->node = c;
1364 extent_buffer_get(c);
1365 path->nodes[level] = c;
1366 path->slots[level] = 0;
1367
1368 if (root->ref_cows && lower_gen != trans->transid) {
1369 struct btrfs_path *back_path = btrfs_alloc_path();
1370 int ret;
1371 ret = btrfs_insert_extent_backref(trans,
1372 root->fs_info->extent_root,
1373 path, lower->start,
1374 root->root_key.objectid,
1375 trans->transid, 0, 0);
1376 BUG_ON(ret);
1377 btrfs_free_path(back_path);
1378 }
1379 return 0;
1380 }
1381
1382 /*
1383 * worker function to insert a single pointer in a node.
1384 * the node should have enough room for the pointer already
1385 *
1386 * slot and level indicate where you want the key to go, and
1387 * blocknr is the block the key points to.
1388 *
1389 * returns zero on success and < 0 on any error
1390 */
1391 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1392 *root, struct btrfs_path *path, struct btrfs_disk_key
1393 *key, u64 bytenr, int slot, int level)
1394 {
1395 struct extent_buffer *lower;
1396 int nritems;
1397
1398 BUG_ON(!path->nodes[level]);
1399 lower = path->nodes[level];
1400 nritems = btrfs_header_nritems(lower);
1401 if (slot > nritems)
1402 BUG();
1403 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1404 BUG();
1405 if (slot != nritems) {
1406 memmove_extent_buffer(lower,
1407 btrfs_node_key_ptr_offset(slot + 1),
1408 btrfs_node_key_ptr_offset(slot),
1409 (nritems - slot) * sizeof(struct btrfs_key_ptr));
1410 }
1411 btrfs_set_node_key(lower, key, slot);
1412 btrfs_set_node_blockptr(lower, slot, bytenr);
1413 WARN_ON(trans->transid == 0);
1414 btrfs_set_node_ptr_generation(lower, slot, trans->transid);
1415 btrfs_set_header_nritems(lower, nritems + 1);
1416 btrfs_mark_buffer_dirty(lower);
1417 return 0;
1418 }
1419
1420 /*
1421 * split the node at the specified level in path in two.
1422 * The path is corrected to point to the appropriate node after the split
1423 *
1424 * Before splitting this tries to make some room in the node by pushing
1425 * left and right, if either one works, it returns right away.
1426 *
1427 * returns 0 on success and < 0 on failure
1428 */
1429 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1430 *root, struct btrfs_path *path, int level)
1431 {
1432 u64 root_gen;
1433 struct extent_buffer *c;
1434 struct extent_buffer *split;
1435 struct btrfs_disk_key disk_key;
1436 int mid;
1437 int ret;
1438 int wret;
1439 u32 c_nritems;
1440
1441 c = path->nodes[level];
1442 WARN_ON(btrfs_header_generation(c) != trans->transid);
1443 if (c == root->node) {
1444 /* trying to split the root, lets make a new one */
1445 ret = insert_new_root(trans, root, path, level + 1);
1446 if (ret)
1447 return ret;
1448 } else {
1449 ret = push_nodes_for_insert(trans, root, path, level);
1450 c = path->nodes[level];
1451 if (!ret && btrfs_header_nritems(c) <
1452 BTRFS_NODEPTRS_PER_BLOCK(root) - 1)
1453 return 0;
1454 if (ret < 0)
1455 return ret;
1456 }
1457
1458 c_nritems = btrfs_header_nritems(c);
1459 if (root->ref_cows)
1460 root_gen = trans->transid;
1461 else
1462 root_gen = 0;
1463
1464 btrfs_node_key(c, &disk_key, 0);
1465 split = __btrfs_alloc_free_block(trans, root, root->nodesize,
1466 root->root_key.objectid,
1467 root_gen,
1468 btrfs_disk_key_objectid(&disk_key),
1469 level, c->start, 0);
1470 if (IS_ERR(split))
1471 return PTR_ERR(split);
1472
1473 btrfs_set_header_flags(split, btrfs_header_flags(c));
1474 btrfs_set_header_level(split, btrfs_header_level(c));
1475 btrfs_set_header_bytenr(split, split->start);
1476 btrfs_set_header_generation(split, trans->transid);
1477 btrfs_set_header_owner(split, root->root_key.objectid);
1478 write_extent_buffer(split, root->fs_info->fsid,
1479 (unsigned long)btrfs_header_fsid(split),
1480 BTRFS_FSID_SIZE);
1481
1482 mid = (c_nritems + 1) / 2;
1483
1484 copy_extent_buffer(split, c,
1485 btrfs_node_key_ptr_offset(0),
1486 btrfs_node_key_ptr_offset(mid),
1487 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1488 btrfs_set_header_nritems(split, c_nritems - mid);
1489 btrfs_set_header_nritems(c, mid);
1490 ret = 0;
1491
1492 btrfs_mark_buffer_dirty(c);
1493 btrfs_mark_buffer_dirty(split);
1494
1495 btrfs_node_key(split, &disk_key, 0);
1496 wret = insert_ptr(trans, root, path, &disk_key, split->start,
1497 path->slots[level + 1] + 1,
1498 level + 1);
1499 if (wret)
1500 ret = wret;
1501
1502 if (path->slots[level] >= mid) {
1503 path->slots[level] -= mid;
1504 free_extent_buffer(c);
1505 path->nodes[level] = split;
1506 path->slots[level + 1] += 1;
1507 } else {
1508 free_extent_buffer(split);
1509 }
1510 return ret;
1511 }
1512
1513 /*
1514 * how many bytes are required to store the items in a leaf. start
1515 * and nr indicate which items in the leaf to check. This totals up the
1516 * space used both by the item structs and the item data
1517 */
1518 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1519 {
1520 int data_len;
1521 int nritems = btrfs_header_nritems(l);
1522 int end = min(nritems, start + nr) - 1;
1523
1524 if (!nr)
1525 return 0;
1526 data_len = btrfs_item_end_nr(l, start);
1527 data_len = data_len - btrfs_item_offset_nr(l, end);
1528 data_len += sizeof(struct btrfs_item) * nr;
1529 WARN_ON(data_len < 0);
1530 return data_len;
1531 }
1532
1533 /*
1534 * The space between the end of the leaf items and
1535 * the start of the leaf data. IOW, how much room
1536 * the leaf has left for both items and data
1537 */
1538 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1539 {
1540 int nritems = btrfs_header_nritems(leaf);
1541 int ret;
1542 ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1543 if (ret < 0) {
1544 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1545 ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
1546 leaf_space_used(leaf, 0, nritems), nritems);
1547 }
1548 return ret;
1549 }
1550
1551 /*
1552 * push some data in the path leaf to the right, trying to free up at
1553 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1554 *
1555 * returns 1 if the push failed because the other node didn't have enough
1556 * room, 0 if everything worked out and < 0 if there were major errors.
1557 */
1558 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1559 *root, struct btrfs_path *path, int data_size,
1560 int empty)
1561 {
1562 struct extent_buffer *left = path->nodes[0];
1563 struct extent_buffer *right;
1564 struct extent_buffer *upper;
1565 struct btrfs_disk_key disk_key;
1566 int slot;
1567 u32 i;
1568 int free_space;
1569 int push_space = 0;
1570 int push_items = 0;
1571 struct btrfs_item *item;
1572 u32 left_nritems;
1573 u32 nr;
1574 u32 right_nritems;
1575 u32 data_end;
1576 u32 this_item_size;
1577 int ret;
1578
1579 slot = path->slots[1];
1580 if (!path->nodes[1]) {
1581 return 1;
1582 }
1583 upper = path->nodes[1];
1584 if (slot >= btrfs_header_nritems(upper) - 1)
1585 return 1;
1586
1587 right = read_tree_block(root, btrfs_node_blockptr(upper, slot + 1),
1588 root->leafsize);
1589 free_space = btrfs_leaf_free_space(root, right);
1590 if (free_space < data_size + sizeof(struct btrfs_item)) {
1591 free_extent_buffer(right);
1592 return 1;
1593 }
1594
1595 /* cow and double check */
1596 ret = btrfs_cow_block(trans, root, right, upper,
1597 slot + 1, &right);
1598 if (ret) {
1599 free_extent_buffer(right);
1600 return 1;
1601 }
1602 free_space = btrfs_leaf_free_space(root, right);
1603 if (free_space < data_size + sizeof(struct btrfs_item)) {
1604 free_extent_buffer(right);
1605 return 1;
1606 }
1607
1608 left_nritems = btrfs_header_nritems(left);
1609 if (left_nritems == 0) {
1610 free_extent_buffer(right);
1611 return 1;
1612 }
1613
1614 if (empty)
1615 nr = 0;
1616 else
1617 nr = 1;
1618
1619 i = left_nritems - 1;
1620 while (i >= nr) {
1621 item = btrfs_item_nr(left, i);
1622
1623 if (path->slots[0] == i)
1624 push_space += data_size + sizeof(*item);
1625
1626 if (!left->map_token) {
1627 map_extent_buffer(left, (unsigned long)item,
1628 sizeof(struct btrfs_item),
1629 &left->map_token, &left->kaddr,
1630 &left->map_start, &left->map_len,
1631 KM_USER1);
1632 }
1633
1634 this_item_size = btrfs_item_size(left, item);
1635 if (this_item_size + sizeof(*item) + push_space > free_space)
1636 break;
1637 push_items++;
1638 push_space += this_item_size + sizeof(*item);
1639 if (i == 0)
1640 break;
1641 i--;
1642 }
1643 if (left->map_token) {
1644 unmap_extent_buffer(left, left->map_token, KM_USER1);
1645 left->map_token = NULL;
1646 }
1647
1648 if (push_items == 0) {
1649 free_extent_buffer(right);
1650 return 1;
1651 }
1652
1653 if (!empty && push_items == left_nritems)
1654 WARN_ON(1);
1655
1656 /* push left to right */
1657 right_nritems = btrfs_header_nritems(right);
1658
1659 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1660 push_space -= leaf_data_end(root, left);
1661
1662 /* make room in the right data area */
1663 data_end = leaf_data_end(root, right);
1664 memmove_extent_buffer(right,
1665 btrfs_leaf_data(right) + data_end - push_space,
1666 btrfs_leaf_data(right) + data_end,
1667 BTRFS_LEAF_DATA_SIZE(root) - data_end);
1668
1669 /* copy from the left data area */
1670 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1671 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1672 btrfs_leaf_data(left) + leaf_data_end(root, left),
1673 push_space);
1674
1675 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1676 btrfs_item_nr_offset(0),
1677 right_nritems * sizeof(struct btrfs_item));
1678
1679 /* copy the items from left to right */
1680 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1681 btrfs_item_nr_offset(left_nritems - push_items),
1682 push_items * sizeof(struct btrfs_item));
1683
1684 /* update the item pointers */
1685 right_nritems += push_items;
1686 btrfs_set_header_nritems(right, right_nritems);
1687 push_space = BTRFS_LEAF_DATA_SIZE(root);
1688 for (i = 0; i < right_nritems; i++) {
1689 item = btrfs_item_nr(right, i);
1690 if (!right->map_token) {
1691 map_extent_buffer(right, (unsigned long)item,
1692 sizeof(struct btrfs_item),
1693 &right->map_token, &right->kaddr,
1694 &right->map_start, &right->map_len,
1695 KM_USER1);
1696 }
1697 push_space -= btrfs_item_size(right, item);
1698 btrfs_set_item_offset(right, item, push_space);
1699 }
1700
1701 if (right->map_token) {
1702 unmap_extent_buffer(right, right->map_token, KM_USER1);
1703 right->map_token = NULL;
1704 }
1705 left_nritems -= push_items;
1706 btrfs_set_header_nritems(left, left_nritems);
1707
1708 if (left_nritems)
1709 btrfs_mark_buffer_dirty(left);
1710 btrfs_mark_buffer_dirty(right);
1711
1712 btrfs_item_key(right, &disk_key, 0);
1713 btrfs_set_node_key(upper, &disk_key, slot + 1);
1714 btrfs_mark_buffer_dirty(upper);
1715
1716 /* then fixup the leaf pointer in the path */
1717 if (path->slots[0] >= left_nritems) {
1718 path->slots[0] -= left_nritems;
1719 free_extent_buffer(path->nodes[0]);
1720 path->nodes[0] = right;
1721 path->slots[1] += 1;
1722 } else {
1723 free_extent_buffer(right);
1724 }
1725 return 0;
1726 }
1727 /*
1728 * push some data in the path leaf to the left, trying to free up at
1729 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1730 */
1731 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1732 *root, struct btrfs_path *path, int data_size,
1733 int empty)
1734 {
1735 struct btrfs_disk_key disk_key;
1736 struct extent_buffer *right = path->nodes[0];
1737 struct extent_buffer *left;
1738 int slot;
1739 int i;
1740 int free_space;
1741 int push_space = 0;
1742 int push_items = 0;
1743 struct btrfs_item *item;
1744 u32 old_left_nritems;
1745 u32 right_nritems;
1746 u32 nr;
1747 int ret = 0;
1748 int wret;
1749 u32 this_item_size;
1750 u32 old_left_item_size;
1751
1752 slot = path->slots[1];
1753 if (slot == 0)
1754 return 1;
1755 if (!path->nodes[1])
1756 return 1;
1757
1758 right_nritems = btrfs_header_nritems(right);
1759 if (right_nritems == 0) {
1760 return 1;
1761 }
1762
1763 left = read_tree_block(root, btrfs_node_blockptr(path->nodes[1],
1764 slot - 1), root->leafsize);
1765 free_space = btrfs_leaf_free_space(root, left);
1766 if (free_space < data_size + sizeof(struct btrfs_item)) {
1767 free_extent_buffer(left);
1768 return 1;
1769 }
1770
1771 /* cow and double check */
1772 ret = btrfs_cow_block(trans, root, left,
1773 path->nodes[1], slot - 1, &left);
1774 if (ret) {
1775 /* we hit -ENOSPC, but it isn't fatal here */
1776 free_extent_buffer(left);
1777 return 1;
1778 }
1779
1780 free_space = btrfs_leaf_free_space(root, left);
1781 if (free_space < data_size + sizeof(struct btrfs_item)) {
1782 free_extent_buffer(left);
1783 return 1;
1784 }
1785
1786 if (empty)
1787 nr = right_nritems;
1788 else
1789 nr = right_nritems - 1;
1790
1791 for (i = 0; i < nr; i++) {
1792 item = btrfs_item_nr(right, i);
1793 if (!right->map_token) {
1794 map_extent_buffer(right, (unsigned long)item,
1795 sizeof(struct btrfs_item),
1796 &right->map_token, &right->kaddr,
1797 &right->map_start, &right->map_len,
1798 KM_USER1);
1799 }
1800
1801 if (path->slots[0] == i)
1802 push_space += data_size + sizeof(*item);
1803
1804 this_item_size = btrfs_item_size(right, item);
1805 if (this_item_size + sizeof(*item) + push_space > free_space)
1806 break;
1807
1808 push_items++;
1809 push_space += this_item_size + sizeof(*item);
1810 }
1811
1812 if (right->map_token) {
1813 unmap_extent_buffer(right, right->map_token, KM_USER1);
1814 right->map_token = NULL;
1815 }
1816
1817 if (push_items == 0) {
1818 free_extent_buffer(left);
1819 return 1;
1820 }
1821 if (!empty && push_items == btrfs_header_nritems(right))
1822 WARN_ON(1);
1823
1824 /* push data from right to left */
1825 copy_extent_buffer(left, right,
1826 btrfs_item_nr_offset(btrfs_header_nritems(left)),
1827 btrfs_item_nr_offset(0),
1828 push_items * sizeof(struct btrfs_item));
1829
1830 push_space = BTRFS_LEAF_DATA_SIZE(root) -
1831 btrfs_item_offset_nr(right, push_items -1);
1832
1833 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
1834 leaf_data_end(root, left) - push_space,
1835 btrfs_leaf_data(right) +
1836 btrfs_item_offset_nr(right, push_items - 1),
1837 push_space);
1838 old_left_nritems = btrfs_header_nritems(left);
1839 BUG_ON(old_left_nritems < 0);
1840
1841 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
1842 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1843 u32 ioff;
1844
1845 item = btrfs_item_nr(left, i);
1846 if (!left->map_token) {
1847 map_extent_buffer(left, (unsigned long)item,
1848 sizeof(struct btrfs_item),
1849 &left->map_token, &left->kaddr,
1850 &left->map_start, &left->map_len,
1851 KM_USER1);
1852 }
1853
1854 ioff = btrfs_item_offset(left, item);
1855 btrfs_set_item_offset(left, item,
1856 ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
1857 }
1858 btrfs_set_header_nritems(left, old_left_nritems + push_items);
1859 if (left->map_token) {
1860 unmap_extent_buffer(left, left->map_token, KM_USER1);
1861 left->map_token = NULL;
1862 }
1863
1864 /* fixup right node */
1865 if (push_items > right_nritems) {
1866 printk("push items %d nr %u\n", push_items, right_nritems);
1867 WARN_ON(1);
1868 }
1869
1870 if (push_items < right_nritems) {
1871 push_space = btrfs_item_offset_nr(right, push_items - 1) -
1872 leaf_data_end(root, right);
1873 memmove_extent_buffer(right, btrfs_leaf_data(right) +
1874 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1875 btrfs_leaf_data(right) +
1876 leaf_data_end(root, right), push_space);
1877
1878 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
1879 btrfs_item_nr_offset(push_items),
1880 (btrfs_header_nritems(right) - push_items) *
1881 sizeof(struct btrfs_item));
1882 }
1883 right_nritems -= push_items;
1884 btrfs_set_header_nritems(right, right_nritems);
1885 push_space = BTRFS_LEAF_DATA_SIZE(root);
1886 for (i = 0; i < right_nritems; i++) {
1887 item = btrfs_item_nr(right, i);
1888
1889 if (!right->map_token) {
1890 map_extent_buffer(right, (unsigned long)item,
1891 sizeof(struct btrfs_item),
1892 &right->map_token, &right->kaddr,
1893 &right->map_start, &right->map_len,
1894 KM_USER1);
1895 }
1896
1897 push_space = push_space - btrfs_item_size(right, item);
1898 btrfs_set_item_offset(right, item, push_space);
1899 }
1900 if (right->map_token) {
1901 unmap_extent_buffer(right, right->map_token, KM_USER1);
1902 right->map_token = NULL;
1903 }
1904
1905 btrfs_mark_buffer_dirty(left);
1906 if (right_nritems)
1907 btrfs_mark_buffer_dirty(right);
1908
1909 btrfs_item_key(right, &disk_key, 0);
1910 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1911 if (wret)
1912 ret = wret;
1913
1914 /* then fixup the leaf pointer in the path */
1915 if (path->slots[0] < push_items) {
1916 path->slots[0] += old_left_nritems;
1917 free_extent_buffer(path->nodes[0]);
1918 path->nodes[0] = left;
1919 path->slots[1] -= 1;
1920 } else {
1921 free_extent_buffer(left);
1922 path->slots[0] -= push_items;
1923 }
1924 BUG_ON(path->slots[0] < 0);
1925 return ret;
1926 }
1927
1928 /*
1929 * split the path's leaf in two, making sure there is at least data_size
1930 * available for the resulting leaf level of the path.
1931 *
1932 * returns 0 if all went well and < 0 on failure.
1933 */
1934 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1935 *root, struct btrfs_key *ins_key,
1936 struct btrfs_path *path, int data_size, int extend)
1937 {
1938 u64 root_gen;
1939 struct extent_buffer *l;
1940 u32 nritems;
1941 int mid;
1942 int slot;
1943 struct extent_buffer *right;
1944 int space_needed = data_size + sizeof(struct btrfs_item);
1945 int data_copy_size;
1946 int rt_data_off;
1947 int i;
1948 int ret = 0;
1949 int wret;
1950 int double_split;
1951 int num_doubles = 0;
1952 struct btrfs_disk_key disk_key;
1953
1954 if (extend)
1955 space_needed = data_size;
1956
1957 if (root->ref_cows)
1958 root_gen = trans->transid;
1959 else
1960 root_gen = 0;
1961
1962 /* first try to make some room by pushing left and right */
1963 if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
1964 wret = push_leaf_right(trans, root, path, data_size, 0);
1965 if (wret < 0) {
1966 return wret;
1967 }
1968 if (wret) {
1969 wret = push_leaf_left(trans, root, path, data_size, 0);
1970 if (wret < 0)
1971 return wret;
1972 }
1973 l = path->nodes[0];
1974
1975 /* did the pushes work? */
1976 if (btrfs_leaf_free_space(root, l) >= space_needed)
1977 return 0;
1978 }
1979
1980 if (!path->nodes[1]) {
1981 ret = insert_new_root(trans, root, path, 1);
1982 if (ret)
1983 return ret;
1984 }
1985 again:
1986 double_split = 0;
1987 l = path->nodes[0];
1988 slot = path->slots[0];
1989 nritems = btrfs_header_nritems(l);
1990 mid = (nritems + 1)/ 2;
1991
1992 btrfs_item_key(l, &disk_key, 0);
1993
1994 right = __btrfs_alloc_free_block(trans, root, root->leafsize,
1995 root->root_key.objectid,
1996 root_gen, disk_key.objectid, 0,
1997 l->start, 0);
1998 if (IS_ERR(right))
1999 return PTR_ERR(right);
2000
2001 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
2002 btrfs_set_header_bytenr(right, right->start);
2003 btrfs_set_header_generation(right, trans->transid);
2004 btrfs_set_header_owner(right, root->root_key.objectid);
2005 btrfs_set_header_level(right, 0);
2006 write_extent_buffer(right, root->fs_info->fsid,
2007 (unsigned long)btrfs_header_fsid(right),
2008 BTRFS_FSID_SIZE);
2009 if (mid <= slot) {
2010 if (nritems == 1 ||
2011 leaf_space_used(l, mid, nritems - mid) + space_needed >
2012 BTRFS_LEAF_DATA_SIZE(root)) {
2013 if (slot >= nritems) {
2014 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2015 btrfs_set_header_nritems(right, 0);
2016 wret = insert_ptr(trans, root, path,
2017 &disk_key, right->start,
2018 path->slots[1] + 1, 1);
2019 if (wret)
2020 ret = wret;
2021 free_extent_buffer(path->nodes[0]);
2022 path->nodes[0] = right;
2023 path->slots[0] = 0;
2024 path->slots[1] += 1;
2025 return ret;
2026 }
2027 mid = slot;
2028 if (mid != nritems &&
2029 leaf_space_used(l, mid, nritems - mid) +
2030 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2031 double_split = 1;
2032 }
2033 }
2034 } else {
2035 if (leaf_space_used(l, 0, mid + 1) + space_needed >
2036 BTRFS_LEAF_DATA_SIZE(root)) {
2037 if (!extend && slot == 0) {
2038 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2039 btrfs_set_header_nritems(right, 0);
2040 wret = insert_ptr(trans, root, path,
2041 &disk_key,
2042 right->start,
2043 path->slots[1], 1);
2044 if (wret)
2045 ret = wret;
2046 free_extent_buffer(path->nodes[0]);
2047 path->nodes[0] = right;
2048 path->slots[0] = 0;
2049 if (path->slots[1] == 0) {
2050 wret = fixup_low_keys(trans, root,
2051 path, &disk_key, 1);
2052 if (wret)
2053 ret = wret;
2054 }
2055 return ret;
2056 } else if (extend && slot == 0) {
2057 mid = 1;
2058 } else {
2059 mid = slot;
2060 if (mid != nritems &&
2061 leaf_space_used(l, mid, nritems - mid) +
2062 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2063 double_split = 1;
2064 }
2065 }
2066 }
2067 }
2068 nritems = nritems - mid;
2069 btrfs_set_header_nritems(right, nritems);
2070 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
2071
2072 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
2073 btrfs_item_nr_offset(mid),
2074 nritems * sizeof(struct btrfs_item));
2075
2076 copy_extent_buffer(right, l,
2077 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
2078 data_copy_size, btrfs_leaf_data(l) +
2079 leaf_data_end(root, l), data_copy_size);
2080
2081 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
2082 btrfs_item_end_nr(l, mid);
2083
2084 for (i = 0; i < nritems; i++) {
2085 struct btrfs_item *item = btrfs_item_nr(right, i);
2086 u32 ioff;
2087
2088 if (!right->map_token) {
2089 map_extent_buffer(right, (unsigned long)item,
2090 sizeof(struct btrfs_item),
2091 &right->map_token, &right->kaddr,
2092 &right->map_start, &right->map_len,
2093 KM_USER1);
2094 }
2095
2096 ioff = btrfs_item_offset(right, item);
2097 btrfs_set_item_offset(right, item, ioff + rt_data_off);
2098 }
2099
2100 if (right->map_token) {
2101 unmap_extent_buffer(right, right->map_token, KM_USER1);
2102 right->map_token = NULL;
2103 }
2104
2105 btrfs_set_header_nritems(l, mid);
2106 ret = 0;
2107 btrfs_item_key(right, &disk_key, 0);
2108 wret = insert_ptr(trans, root, path, &disk_key, right->start,
2109 path->slots[1] + 1, 1);
2110 if (wret)
2111 ret = wret;
2112
2113 btrfs_mark_buffer_dirty(right);
2114 btrfs_mark_buffer_dirty(l);
2115 BUG_ON(path->slots[0] != slot);
2116
2117 if (mid <= slot) {
2118 free_extent_buffer(path->nodes[0]);
2119 path->nodes[0] = right;
2120 path->slots[0] -= mid;
2121 path->slots[1] += 1;
2122 } else
2123 free_extent_buffer(right);
2124
2125 BUG_ON(path->slots[0] < 0);
2126
2127 if (double_split) {
2128 BUG_ON(num_doubles != 0);
2129 num_doubles++;
2130 goto again;
2131 }
2132 return ret;
2133 }
2134
2135 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
2136 struct btrfs_root *root,
2137 struct btrfs_path *path,
2138 u32 new_size, int from_end)
2139 {
2140 int ret = 0;
2141 int slot;
2142 int slot_orig;
2143 struct extent_buffer *leaf;
2144 struct btrfs_item *item;
2145 u32 nritems;
2146 unsigned int data_end;
2147 unsigned int old_data_start;
2148 unsigned int old_size;
2149 unsigned int size_diff;
2150 int i;
2151
2152 slot_orig = path->slots[0];
2153 leaf = path->nodes[0];
2154 slot = path->slots[0];
2155
2156 old_size = btrfs_item_size_nr(leaf, slot);
2157 if (old_size == new_size)
2158 return 0;
2159
2160 nritems = btrfs_header_nritems(leaf);
2161 data_end = leaf_data_end(root, leaf);
2162
2163 old_data_start = btrfs_item_offset_nr(leaf, slot);
2164
2165 size_diff = old_size - new_size;
2166
2167 BUG_ON(slot < 0);
2168 BUG_ON(slot >= nritems);
2169
2170 /*
2171 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2172 */
2173 /* first correct the data pointers */
2174 for (i = slot; i < nritems; i++) {
2175 u32 ioff;
2176 item = btrfs_item_nr(leaf, i);
2177
2178 if (!leaf->map_token) {
2179 map_extent_buffer(leaf, (unsigned long)item,
2180 sizeof(struct btrfs_item),
2181 &leaf->map_token, &leaf->kaddr,
2182 &leaf->map_start, &leaf->map_len,
2183 KM_USER1);
2184 }
2185
2186 ioff = btrfs_item_offset(leaf, item);
2187 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2188 }
2189
2190 if (leaf->map_token) {
2191 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2192 leaf->map_token = NULL;
2193 }
2194
2195 /* shift the data */
2196 if (from_end) {
2197 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2198 data_end + size_diff, btrfs_leaf_data(leaf) +
2199 data_end, old_data_start + new_size - data_end);
2200 } else {
2201 struct btrfs_disk_key disk_key;
2202 u64 offset;
2203
2204 btrfs_item_key(leaf, &disk_key, slot);
2205
2206 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2207 unsigned long ptr;
2208 struct btrfs_file_extent_item *fi;
2209
2210 fi = btrfs_item_ptr(leaf, slot,
2211 struct btrfs_file_extent_item);
2212 fi = (struct btrfs_file_extent_item *)(
2213 (unsigned long)fi - size_diff);
2214
2215 if (btrfs_file_extent_type(leaf, fi) ==
2216 BTRFS_FILE_EXTENT_INLINE) {
2217 ptr = btrfs_item_ptr_offset(leaf, slot);
2218 memmove_extent_buffer(leaf, ptr,
2219 (unsigned long)fi,
2220 offsetof(struct btrfs_file_extent_item,
2221 disk_bytenr));
2222 }
2223 }
2224
2225 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2226 data_end + size_diff, btrfs_leaf_data(leaf) +
2227 data_end, old_data_start - data_end);
2228
2229 offset = btrfs_disk_key_offset(&disk_key);
2230 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2231 btrfs_set_item_key(leaf, &disk_key, slot);
2232 if (slot == 0)
2233 fixup_low_keys(trans, root, path, &disk_key, 1);
2234 }
2235
2236 item = btrfs_item_nr(leaf, slot);
2237 btrfs_set_item_size(leaf, item, new_size);
2238 btrfs_mark_buffer_dirty(leaf);
2239
2240 ret = 0;
2241 if (btrfs_leaf_free_space(root, leaf) < 0) {
2242 btrfs_print_leaf(root, leaf);
2243 BUG();
2244 }
2245 return ret;
2246 }
2247
2248 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2249 struct btrfs_root *root, struct btrfs_path *path,
2250 u32 data_size)
2251 {
2252 int ret = 0;
2253 int slot;
2254 int slot_orig;
2255 struct extent_buffer *leaf;
2256 struct btrfs_item *item;
2257 u32 nritems;
2258 unsigned int data_end;
2259 unsigned int old_data;
2260 unsigned int old_size;
2261 int i;
2262
2263 slot_orig = path->slots[0];
2264 leaf = path->nodes[0];
2265
2266 nritems = btrfs_header_nritems(leaf);
2267 data_end = leaf_data_end(root, leaf);
2268
2269 if (btrfs_leaf_free_space(root, leaf) < data_size) {
2270 btrfs_print_leaf(root, leaf);
2271 BUG();
2272 }
2273 slot = path->slots[0];
2274 old_data = btrfs_item_end_nr(leaf, slot);
2275
2276 BUG_ON(slot < 0);
2277 if (slot >= nritems) {
2278 btrfs_print_leaf(root, leaf);
2279 printk("slot %d too large, nritems %d\n", slot, nritems);
2280 BUG_ON(1);
2281 }
2282
2283 /*
2284 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2285 */
2286 /* first correct the data pointers */
2287 for (i = slot; i < nritems; i++) {
2288 u32 ioff;
2289 item = btrfs_item_nr(leaf, i);
2290
2291 if (!leaf->map_token) {
2292 map_extent_buffer(leaf, (unsigned long)item,
2293 sizeof(struct btrfs_item),
2294 &leaf->map_token, &leaf->kaddr,
2295 &leaf->map_start, &leaf->map_len,
2296 KM_USER1);
2297 }
2298 ioff = btrfs_item_offset(leaf, item);
2299 btrfs_set_item_offset(leaf, item, ioff - data_size);
2300 }
2301
2302 if (leaf->map_token) {
2303 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2304 leaf->map_token = NULL;
2305 }
2306
2307 /* shift the data */
2308 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2309 data_end - data_size, btrfs_leaf_data(leaf) +
2310 data_end, old_data - data_end);
2311
2312 data_end = old_data;
2313 old_size = btrfs_item_size_nr(leaf, slot);
2314 item = btrfs_item_nr(leaf, slot);
2315 btrfs_set_item_size(leaf, item, old_size + data_size);
2316 btrfs_mark_buffer_dirty(leaf);
2317
2318 ret = 0;
2319 if (btrfs_leaf_free_space(root, leaf) < 0) {
2320 btrfs_print_leaf(root, leaf);
2321 BUG();
2322 }
2323 return ret;
2324 }
2325
2326 /*
2327 * Given a key and some data, insert an item into the tree.
2328 * This does all the path init required, making room in the tree if needed.
2329 */
2330 int btrfs_insert_empty_item(struct btrfs_trans_handle *trans,
2331 struct btrfs_root *root,
2332 struct btrfs_path *path,
2333 struct btrfs_key *cpu_key, u32 data_size)
2334 {
2335 struct extent_buffer *leaf;
2336 struct btrfs_item *item;
2337 int ret = 0;
2338 int slot;
2339 int slot_orig;
2340 u32 nritems;
2341 unsigned int data_end;
2342 struct btrfs_disk_key disk_key;
2343
2344 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2345
2346 /* create a root if there isn't one */
2347 if (!root->node)
2348 BUG();
2349
2350 ret = btrfs_search_slot(trans, root, cpu_key, path, data_size, 1);
2351 if (ret == 0) {
2352 return -EEXIST;
2353 }
2354 if (ret < 0)
2355 goto out;
2356
2357 slot_orig = path->slots[0];
2358 leaf = path->nodes[0];
2359
2360 nritems = btrfs_header_nritems(leaf);
2361 data_end = leaf_data_end(root, leaf);
2362
2363 if (btrfs_leaf_free_space(root, leaf) <
2364 sizeof(struct btrfs_item) + data_size) {
2365 btrfs_print_leaf(root, leaf);
2366 printk("not enough freespace need %u have %d\n",
2367 data_size, btrfs_leaf_free_space(root, leaf));
2368 BUG();
2369 }
2370
2371 slot = path->slots[0];
2372 BUG_ON(slot < 0);
2373
2374 if (slot != nritems) {
2375 int i;
2376 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2377
2378 if (old_data < data_end) {
2379 btrfs_print_leaf(root, leaf);
2380 printk("slot %d old_data %d data_end %d\n",
2381 slot, old_data, data_end);
2382 BUG_ON(1);
2383 }
2384 /*
2385 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2386 */
2387 /* first correct the data pointers */
2388 WARN_ON(leaf->map_token);
2389 for (i = slot; i < nritems; i++) {
2390 u32 ioff;
2391
2392 item = btrfs_item_nr(leaf, i);
2393 if (!leaf->map_token) {
2394 map_extent_buffer(leaf, (unsigned long)item,
2395 sizeof(struct btrfs_item),
2396 &leaf->map_token, &leaf->kaddr,
2397 &leaf->map_start, &leaf->map_len,
2398 KM_USER1);
2399 }
2400
2401 ioff = btrfs_item_offset(leaf, item);
2402 btrfs_set_item_offset(leaf, item, ioff - data_size);
2403 }
2404 if (leaf->map_token) {
2405 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2406 leaf->map_token = NULL;
2407 }
2408
2409 /* shift the items */
2410 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1),
2411 btrfs_item_nr_offset(slot),
2412 (nritems - slot) * sizeof(struct btrfs_item));
2413
2414 /* shift the data */
2415 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2416 data_end - data_size, btrfs_leaf_data(leaf) +
2417 data_end, old_data - data_end);
2418 data_end = old_data;
2419 }
2420
2421 /* setup the item for the new data */
2422 btrfs_set_item_key(leaf, &disk_key, slot);
2423 item = btrfs_item_nr(leaf, slot);
2424 btrfs_set_item_offset(leaf, item, data_end - data_size);
2425 btrfs_set_item_size(leaf, item, data_size);
2426 btrfs_set_header_nritems(leaf, nritems + 1);
2427 btrfs_mark_buffer_dirty(leaf);
2428
2429 ret = 0;
2430 if (slot == 0)
2431 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2432
2433 if (btrfs_leaf_free_space(root, leaf) < 0) {
2434 btrfs_print_leaf(root, leaf);
2435 BUG();
2436 }
2437 out:
2438 return ret;
2439 }
2440
2441 /*
2442 * Given a key and some data, insert an item into the tree.
2443 * This does all the path init required, making room in the tree if needed.
2444 */
2445 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2446 *root, struct btrfs_key *cpu_key, void *data, u32
2447 data_size)
2448 {
2449 int ret = 0;
2450 struct btrfs_path *path;
2451 struct extent_buffer *leaf;
2452 unsigned long ptr;
2453
2454 path = btrfs_alloc_path();
2455 BUG_ON(!path);
2456 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2457 if (!ret) {
2458 leaf = path->nodes[0];
2459 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2460 write_extent_buffer(leaf, data, ptr, data_size);
2461 btrfs_mark_buffer_dirty(leaf);
2462 }
2463 btrfs_free_path(path);
2464 return ret;
2465 }
2466
2467 /*
2468 * delete the pointer from a given node.
2469 *
2470 * If the delete empties a node, the node is removed from the tree,
2471 * continuing all the way the root if required. The root is converted into
2472 * a leaf if all the nodes are emptied.
2473 */
2474 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2475 struct btrfs_path *path, int level, int slot)
2476 {
2477 struct extent_buffer *parent = path->nodes[level];
2478 u32 nritems;
2479 int ret = 0;
2480 int wret;
2481
2482 nritems = btrfs_header_nritems(parent);
2483 if (slot != nritems -1) {
2484 memmove_extent_buffer(parent,
2485 btrfs_node_key_ptr_offset(slot),
2486 btrfs_node_key_ptr_offset(slot + 1),
2487 sizeof(struct btrfs_key_ptr) *
2488 (nritems - slot - 1));
2489 }
2490 nritems--;
2491 btrfs_set_header_nritems(parent, nritems);
2492 if (nritems == 0 && parent == root->node) {
2493 BUG_ON(btrfs_header_level(root->node) != 1);
2494 /* just turn the root into a leaf and break */
2495 btrfs_set_header_level(root->node, 0);
2496 } else if (slot == 0) {
2497 struct btrfs_disk_key disk_key;
2498
2499 btrfs_node_key(parent, &disk_key, 0);
2500 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2501 if (wret)
2502 ret = wret;
2503 }
2504 btrfs_mark_buffer_dirty(parent);
2505 return ret;
2506 }
2507
2508 /*
2509 * delete the item at the leaf level in path. If that empties
2510 * the leaf, remove it from the tree
2511 */
2512 int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2513 struct btrfs_path *path)
2514 {
2515 int slot;
2516 struct extent_buffer *leaf;
2517 struct btrfs_item *item;
2518 int doff;
2519 int dsize;
2520 int ret = 0;
2521 int wret;
2522 u32 nritems;
2523
2524 leaf = path->nodes[0];
2525 slot = path->slots[0];
2526 doff = btrfs_item_offset_nr(leaf, slot);
2527 dsize = btrfs_item_size_nr(leaf, slot);
2528 nritems = btrfs_header_nritems(leaf);
2529
2530 if (slot != nritems - 1) {
2531 int i;
2532 int data_end = leaf_data_end(root, leaf);
2533
2534 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2535 data_end + dsize,
2536 btrfs_leaf_data(leaf) + data_end,
2537 doff - data_end);
2538
2539 for (i = slot + 1; i < nritems; i++) {
2540 u32 ioff;
2541
2542 item = btrfs_item_nr(leaf, i);
2543 if (!leaf->map_token) {
2544 map_extent_buffer(leaf, (unsigned long)item,
2545 sizeof(struct btrfs_item),
2546 &leaf->map_token, &leaf->kaddr,
2547 &leaf->map_start, &leaf->map_len,
2548 KM_USER1);
2549 }
2550 ioff = btrfs_item_offset(leaf, item);
2551 btrfs_set_item_offset(leaf, item, ioff + dsize);
2552 }
2553
2554 if (leaf->map_token) {
2555 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2556 leaf->map_token = NULL;
2557 }
2558
2559 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2560 btrfs_item_nr_offset(slot + 1),
2561 sizeof(struct btrfs_item) *
2562 (nritems - slot - 1));
2563 }
2564 btrfs_set_header_nritems(leaf, nritems - 1);
2565 nritems--;
2566
2567 /* delete the leaf if we've emptied it */
2568 if (nritems == 0) {
2569 if (leaf == root->node) {
2570 btrfs_set_header_level(leaf, 0);
2571 } else {
2572 u64 root_gen = btrfs_header_generation(path->nodes[1]);
2573 clean_tree_block(trans, root, leaf);
2574 wait_on_tree_block_writeback(root, leaf);
2575 wret = del_ptr(trans, root, path, 1, path->slots[1]);
2576 if (wret)
2577 ret = wret;
2578 wret = btrfs_free_extent(trans, root,
2579 leaf->start, leaf->len,
2580 btrfs_header_owner(path->nodes[1]),
2581 root_gen, 0, 0, 1);
2582 if (wret)
2583 ret = wret;
2584 }
2585 } else {
2586 int used = leaf_space_used(leaf, 0, nritems);
2587 if (slot == 0) {
2588 struct btrfs_disk_key disk_key;
2589
2590 btrfs_item_key(leaf, &disk_key, 0);
2591 wret = fixup_low_keys(trans, root, path,
2592 &disk_key, 1);
2593 if (wret)
2594 ret = wret;
2595 }
2596
2597 /* delete the leaf if it is mostly empty */
2598 if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) {
2599 /* push_leaf_left fixes the path.
2600 * make sure the path still points to our leaf
2601 * for possible call to del_ptr below
2602 */
2603 slot = path->slots[1];
2604 extent_buffer_get(leaf);
2605
2606 wret = push_leaf_right(trans, root, path, 1, 1);
2607 if (wret < 0 && wret != -ENOSPC)
2608 ret = wret;
2609
2610 if (path->nodes[0] == leaf &&
2611 btrfs_header_nritems(leaf)) {
2612 wret = push_leaf_left(trans, root, path, 1, 1);
2613 if (wret < 0 && wret != -ENOSPC)
2614 ret = wret;
2615 }
2616
2617 if (btrfs_header_nritems(leaf) == 0) {
2618 u64 root_gen;
2619 u64 bytenr = leaf->start;
2620 u32 blocksize = leaf->len;
2621
2622 root_gen = btrfs_header_generation(
2623 path->nodes[1]);
2624
2625 clean_tree_block(trans, root, leaf);
2626 wait_on_tree_block_writeback(root, leaf);
2627
2628 wret = del_ptr(trans, root, path, 1, slot);
2629 if (wret)
2630 ret = wret;
2631
2632 free_extent_buffer(leaf);
2633 wret = btrfs_free_extent(trans, root, bytenr,
2634 blocksize,
2635 btrfs_header_owner(path->nodes[1]),
2636 root_gen, 0, 0, 1);
2637 if (wret)
2638 ret = wret;
2639 } else {
2640 btrfs_mark_buffer_dirty(leaf);
2641 free_extent_buffer(leaf);
2642 }
2643 } else {
2644 btrfs_mark_buffer_dirty(leaf);
2645 }
2646 }
2647 return ret;
2648 }
2649
2650 /*
2651 * walk up the tree as far as required to find the previous leaf.
2652 * returns 0 if it found something or 1 if there are no lesser leaves.
2653 * returns < 0 on io errors.
2654 */
2655 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
2656 {
2657 int slot;
2658 int level = 1;
2659 u64 bytenr;
2660 struct extent_buffer *c;
2661 struct extent_buffer *next = NULL;
2662
2663 while(level < BTRFS_MAX_LEVEL) {
2664 if (!path->nodes[level])
2665 return 1;
2666
2667 slot = path->slots[level];
2668 c = path->nodes[level];
2669 if (slot == 0) {
2670 level++;
2671 if (level == BTRFS_MAX_LEVEL)
2672 return 1;
2673 continue;
2674 }
2675 slot--;
2676
2677 bytenr = btrfs_node_blockptr(c, slot);
2678 if (next)
2679 free_extent_buffer(next);
2680
2681 next = read_tree_block(root, bytenr,
2682 btrfs_level_size(root, level - 1));
2683 break;
2684 }
2685 path->slots[level] = slot;
2686 while(1) {
2687 level--;
2688 c = path->nodes[level];
2689 free_extent_buffer(c);
2690 path->nodes[level] = next;
2691 path->slots[level] = 0;
2692 if (!level)
2693 break;
2694 next = read_tree_block(root, btrfs_node_blockptr(next, 0),
2695 btrfs_level_size(root, level - 1));
2696 }
2697 return 0;
2698 }
2699
2700 /*
2701 * walk up the tree as far as required to find the next leaf.
2702 * returns 0 if it found something or 1 if there are no greater leaves.
2703 * returns < 0 on io errors.
2704 */
2705 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2706 {
2707 int slot;
2708 int level = 1;
2709 u64 bytenr;
2710 struct extent_buffer *c;
2711 struct extent_buffer *next = NULL;
2712
2713 while(level < BTRFS_MAX_LEVEL) {
2714 if (!path->nodes[level])
2715 return 1;
2716
2717 slot = path->slots[level] + 1;
2718 c = path->nodes[level];
2719 if (slot >= btrfs_header_nritems(c)) {
2720 level++;
2721 if (level == BTRFS_MAX_LEVEL)
2722 return 1;
2723 continue;
2724 }
2725
2726 bytenr = btrfs_node_blockptr(c, slot);
2727 if (next)
2728 free_extent_buffer(next);
2729
2730 if (path->reada)
2731 reada_for_search(root, path, level, slot, 0);
2732
2733 next = read_tree_block(root, bytenr,
2734 btrfs_level_size(root, level -1));
2735 break;
2736 }
2737 path->slots[level] = slot;
2738 while(1) {
2739 level--;
2740 c = path->nodes[level];
2741 free_extent_buffer(c);
2742 path->nodes[level] = next;
2743 path->slots[level] = 0;
2744 if (!level)
2745 break;
2746 if (path->reada)
2747 reada_for_search(root, path, level, 0, 0);
2748 next = read_tree_block(root, btrfs_node_blockptr(next, 0),
2749 btrfs_level_size(root, level - 1));
2750 }
2751 return 0;
2752 }
Linux kernel - Deliverables
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