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btrfs-progs: update CHANGES for 4.7.3
[btrfs-progs-unstable/devel.git] / ctree.c
bloba98ad185e4ff840b2c9a4ff03fe3869a80f29022
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 #include "repair.h"
23 #include "internal.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, int empty);
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
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 = kzalloc(sizeof(struct btrfs_path), GFP_NOFS);
47 return path;
48 }
49
50 void btrfs_free_path(struct btrfs_path *p)
51 {
52 if (!p)
53 return;
54 btrfs_release_path(p);
55 kfree(p);
56 }
57
58 void btrfs_release_path(struct btrfs_path *p)
59 {
60 int i;
61 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
62 if (!p->nodes[i])
63 continue;
64 free_extent_buffer(p->nodes[i]);
65 }
66 memset(p, 0, sizeof(*p));
67 }
68
69 void add_root_to_dirty_list(struct btrfs_root *root)
70 {
71 if (root->track_dirty && list_empty(&root->dirty_list)) {
72 list_add(&root->dirty_list,
73 &root->fs_info->dirty_cowonly_roots);
74 }
75 }
76
77 int btrfs_copy_root(struct btrfs_trans_handle *trans,
78 struct btrfs_root *root,
79 struct extent_buffer *buf,
80 struct extent_buffer **cow_ret, u64 new_root_objectid)
81 {
82 struct extent_buffer *cow;
83 int ret = 0;
84 int level;
85 struct btrfs_root *new_root;
86 struct btrfs_disk_key disk_key;
87
88 new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
89 if (!new_root)
90 return -ENOMEM;
91
92 memcpy(new_root, root, sizeof(*new_root));
93 new_root->root_key.objectid = new_root_objectid;
94
95 WARN_ON(root->ref_cows && trans->transid !=
96 root->fs_info->running_transaction->transid);
97 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
98
99 level = btrfs_header_level(buf);
100 if (level == 0)
101 btrfs_item_key(buf, &disk_key, 0);
102 else
103 btrfs_node_key(buf, &disk_key, 0);
104 cow = btrfs_alloc_free_block(trans, new_root, buf->len,
105 new_root_objectid, &disk_key,
106 level, buf->start, 0);
107 if (IS_ERR(cow)) {
108 kfree(new_root);
109 return PTR_ERR(cow);
110 }
111
112 copy_extent_buffer(cow, buf, 0, 0, cow->len);
113 btrfs_set_header_bytenr(cow, cow->start);
114 btrfs_set_header_generation(cow, trans->transid);
115 btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV);
116 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN |
117 BTRFS_HEADER_FLAG_RELOC);
118 if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID)
119 btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC);
120 else
121 btrfs_set_header_owner(cow, new_root_objectid);
122
123 write_extent_buffer(cow, root->fs_info->fsid,
124 btrfs_header_fsid(), BTRFS_FSID_SIZE);
125
126 WARN_ON(btrfs_header_generation(buf) > trans->transid);
127 ret = btrfs_inc_ref(trans, new_root, cow, 0);
128 kfree(new_root);
129
130 if (ret)
131 return ret;
132
133 btrfs_mark_buffer_dirty(cow);
134 *cow_ret = cow;
135 return 0;
136 }
137
138 /*
139 * check if the tree block can be shared by multiple trees
140 */
141 static int btrfs_block_can_be_shared(struct btrfs_root *root,
142 struct extent_buffer *buf)
143 {
144 /*
145 * Tree blocks not in reference counted trees and tree roots
146 * are never shared. If a block was allocated after the last
147 * snapshot and the block was not allocated by tree relocation,
148 * we know the block is not shared.
149 */
150 if (root->ref_cows &&
151 buf != root->node && buf != root->commit_root &&
152 (btrfs_header_generation(buf) <=
153 btrfs_root_last_snapshot(&root->root_item) ||
154 btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)))
155 return 1;
156 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
157 if (root->ref_cows &&
158 btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
159 return 1;
160 #endif
161 return 0;
162 }
163
164 static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
165 struct btrfs_root *root,
166 struct extent_buffer *buf,
167 struct extent_buffer *cow)
168 {
169 u64 refs;
170 u64 owner;
171 u64 flags;
172 u64 new_flags = 0;
173 int ret;
174
175 /*
176 * Backrefs update rules:
177 *
178 * Always use full backrefs for extent pointers in tree block
179 * allocated by tree relocation.
180 *
181 * If a shared tree block is no longer referenced by its owner
182 * tree (btrfs_header_owner(buf) == root->root_key.objectid),
183 * use full backrefs for extent pointers in tree block.
184 *
185 * If a tree block is been relocating
186 * (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID),
187 * use full backrefs for extent pointers in tree block.
188 * The reason for this is some operations (such as drop tree)
189 * are only allowed for blocks use full backrefs.
190 */
191
192 if (btrfs_block_can_be_shared(root, buf)) {
193 ret = btrfs_lookup_extent_info(trans, root, buf->start,
194 btrfs_header_level(buf), 1,
195 &refs, &flags);
196 BUG_ON(ret);
197 BUG_ON(refs == 0);
198 } else {
199 refs = 1;
200 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
201 btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
202 flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
203 else
204 flags = 0;
205 }
206
207 owner = btrfs_header_owner(buf);
208 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) &&
209 owner == BTRFS_TREE_RELOC_OBJECTID);
210
211 if (refs > 1) {
212 if ((owner == root->root_key.objectid ||
213 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) &&
214 !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) {
215 ret = btrfs_inc_ref(trans, root, buf, 1);
216 BUG_ON(ret);
217
218 if (root->root_key.objectid ==
219 BTRFS_TREE_RELOC_OBJECTID) {
220 ret = btrfs_dec_ref(trans, root, buf, 0);
221 BUG_ON(ret);
222 ret = btrfs_inc_ref(trans, root, cow, 1);
223 BUG_ON(ret);
224 }
225 new_flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
226 } else {
227
228 if (root->root_key.objectid ==
229 BTRFS_TREE_RELOC_OBJECTID)
230 ret = btrfs_inc_ref(trans, root, cow, 1);
231 else
232 ret = btrfs_inc_ref(trans, root, cow, 0);
233 BUG_ON(ret);
234 }
235 if (new_flags != 0) {
236 ret = btrfs_set_block_flags(trans, root, buf->start,
237 btrfs_header_level(buf),
238 new_flags);
239 BUG_ON(ret);
240 }
241 } else {
242 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
243 if (root->root_key.objectid ==
244 BTRFS_TREE_RELOC_OBJECTID)
245 ret = btrfs_inc_ref(trans, root, cow, 1);
246 else
247 ret = btrfs_inc_ref(trans, root, cow, 0);
248 BUG_ON(ret);
249 ret = btrfs_dec_ref(trans, root, buf, 1);
250 BUG_ON(ret);
251 }
252 clean_tree_block(trans, root, buf);
253 }
254 return 0;
255 }
256
257 int __btrfs_cow_block(struct btrfs_trans_handle *trans,
258 struct btrfs_root *root,
259 struct extent_buffer *buf,
260 struct extent_buffer *parent, int parent_slot,
261 struct extent_buffer **cow_ret,
262 u64 search_start, u64 empty_size)
263 {
264 struct extent_buffer *cow;
265 struct btrfs_disk_key disk_key;
266 int level;
267
268 WARN_ON(root->ref_cows && trans->transid !=
269 root->fs_info->running_transaction->transid);
270 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
271
272 level = btrfs_header_level(buf);
273
274 if (level == 0)
275 btrfs_item_key(buf, &disk_key, 0);
276 else
277 btrfs_node_key(buf, &disk_key, 0);
278
279 cow = btrfs_alloc_free_block(trans, root, buf->len,
280 root->root_key.objectid, &disk_key,
281 level, search_start, empty_size);
282 if (IS_ERR(cow))
283 return PTR_ERR(cow);
284
285 copy_extent_buffer(cow, buf, 0, 0, cow->len);
286 btrfs_set_header_bytenr(cow, cow->start);
287 btrfs_set_header_generation(cow, trans->transid);
288 btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV);
289 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN |
290 BTRFS_HEADER_FLAG_RELOC);
291 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
292 btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC);
293 else
294 btrfs_set_header_owner(cow, root->root_key.objectid);
295
296 write_extent_buffer(cow, root->fs_info->fsid,
297 btrfs_header_fsid(), BTRFS_FSID_SIZE);
298
299 WARN_ON(!(buf->flags & EXTENT_BAD_TRANSID) &&
300 btrfs_header_generation(buf) > trans->transid);
301
302 update_ref_for_cow(trans, root, buf, cow);
303
304 if (buf == root->node) {
305 root->node = cow;
306 extent_buffer_get(cow);
307
308 btrfs_free_extent(trans, root, buf->start, buf->len,
309 0, root->root_key.objectid, level, 0);
310 free_extent_buffer(buf);
311 add_root_to_dirty_list(root);
312 } else {
313 btrfs_set_node_blockptr(parent, parent_slot,
314 cow->start);
315 WARN_ON(trans->transid == 0);
316 btrfs_set_node_ptr_generation(parent, parent_slot,
317 trans->transid);
318 btrfs_mark_buffer_dirty(parent);
319 WARN_ON(btrfs_header_generation(parent) != trans->transid);
320
321 btrfs_free_extent(trans, root, buf->start, buf->len,
322 0, root->root_key.objectid, level, 1);
323 }
324 if (!list_empty(&buf->recow)) {
325 list_del_init(&buf->recow);
326 free_extent_buffer(buf);
327 }
328 free_extent_buffer(buf);
329 btrfs_mark_buffer_dirty(cow);
330 *cow_ret = cow;
331 return 0;
332 }
333
334 static inline int should_cow_block(struct btrfs_trans_handle *trans,
335 struct btrfs_root *root,
336 struct extent_buffer *buf)
337 {
338 if (btrfs_header_generation(buf) == trans->transid &&
339 !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN) &&
340 !(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID &&
341 btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)))
342 return 0;
343 return 1;
344 }
345
346 int btrfs_cow_block(struct btrfs_trans_handle *trans,
347 struct btrfs_root *root, struct extent_buffer *buf,
348 struct extent_buffer *parent, int parent_slot,
349 struct extent_buffer **cow_ret)
350 {
351 u64 search_start;
352 int ret;
353 /*
354 if (trans->transaction != root->fs_info->running_transaction) {
355 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
356 root->fs_info->running_transaction->transid);
357 WARN_ON(1);
358 }
359 */
360 if (trans->transid != root->fs_info->generation) {
361 printk(KERN_CRIT "trans %llu running %llu\n",
362 (unsigned long long)trans->transid,
363 (unsigned long long)root->fs_info->generation);
364 WARN_ON(1);
365 }
366 if (!should_cow_block(trans, root, buf)) {
367 *cow_ret = buf;
368 return 0;
369 }
370
371 search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
372 ret = __btrfs_cow_block(trans, root, buf, parent,
373 parent_slot, cow_ret, search_start, 0);
374 return ret;
375 }
376
377 int btrfs_comp_cpu_keys(struct btrfs_key *k1, struct btrfs_key *k2)
378 {
379 if (k1->objectid > k2->objectid)
380 return 1;
381 if (k1->objectid < k2->objectid)
382 return -1;
383 if (k1->type > k2->type)
384 return 1;
385 if (k1->type < k2->type)
386 return -1;
387 if (k1->offset > k2->offset)
388 return 1;
389 if (k1->offset < k2->offset)
390 return -1;
391 return 0;
392 }
393
394 /*
395 * compare two keys in a memcmp fashion
396 */
397 static int btrfs_comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
398 {
399 struct btrfs_key k1;
400
401 btrfs_disk_key_to_cpu(&k1, disk);
402 return btrfs_comp_cpu_keys(&k1, k2);
403 }
404
405 /*
406 * The leaf data grows from end-to-front in the node.
407 * this returns the address of the start of the last item,
408 * which is the stop of the leaf data stack
409 */
410 static inline unsigned int leaf_data_end(struct btrfs_root *root,
411 struct extent_buffer *leaf)
412 {
413 u32 nr = btrfs_header_nritems(leaf);
414 if (nr == 0)
415 return BTRFS_LEAF_DATA_SIZE(root);
416 return btrfs_item_offset_nr(leaf, nr - 1);
417 }
418
419 enum btrfs_tree_block_status
420 btrfs_check_node(struct btrfs_root *root, struct btrfs_disk_key *parent_key,
421 struct extent_buffer *buf)
422 {
423 int i;
424 struct btrfs_key cpukey;
425 struct btrfs_disk_key key;
426 u32 nritems = btrfs_header_nritems(buf);
427 enum btrfs_tree_block_status ret = BTRFS_TREE_BLOCK_INVALID_NRITEMS;
428
429 if (nritems == 0 || nritems > BTRFS_NODEPTRS_PER_BLOCK(root))
430 goto fail;
431
432 ret = BTRFS_TREE_BLOCK_INVALID_PARENT_KEY;
433 if (parent_key && parent_key->type) {
434 btrfs_node_key(buf, &key, 0);
435 if (memcmp(parent_key, &key, sizeof(key)))
436 goto fail;
437 }
438 ret = BTRFS_TREE_BLOCK_BAD_KEY_ORDER;
439 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
440 btrfs_node_key(buf, &key, i);
441 btrfs_node_key_to_cpu(buf, &cpukey, i + 1);
442 if (btrfs_comp_keys(&key, &cpukey) >= 0)
443 goto fail;
444 }
445 return BTRFS_TREE_BLOCK_CLEAN;
446 fail:
447 if (btrfs_header_owner(buf) == BTRFS_EXTENT_TREE_OBJECTID) {
448 if (parent_key)
449 btrfs_disk_key_to_cpu(&cpukey, parent_key);
450 else
451 btrfs_node_key_to_cpu(buf, &cpukey, 0);
452 btrfs_add_corrupt_extent_record(root->fs_info, &cpukey,
453 buf->start, buf->len,
454 btrfs_header_level(buf));
455 }
456 return ret;
457 }
458
459 enum btrfs_tree_block_status
460 btrfs_check_leaf(struct btrfs_root *root, struct btrfs_disk_key *parent_key,
461 struct extent_buffer *buf)
462 {
463 int i;
464 struct btrfs_key cpukey;
465 struct btrfs_disk_key key;
466 u32 nritems = btrfs_header_nritems(buf);
467 enum btrfs_tree_block_status ret = BTRFS_TREE_BLOCK_INVALID_NRITEMS;
468
469 if (nritems * sizeof(struct btrfs_item) > buf->len) {
470 fprintf(stderr, "invalid number of items %llu\n",
471 (unsigned long long)buf->start);
472 goto fail;
473 }
474
475 if (btrfs_header_level(buf) != 0) {
476 ret = BTRFS_TREE_BLOCK_INVALID_LEVEL;
477 fprintf(stderr, "leaf is not a leaf %llu\n",
478 (unsigned long long)btrfs_header_bytenr(buf));
479 goto fail;
480 }
481 if (btrfs_leaf_free_space(root, buf) < 0) {
482 ret = BTRFS_TREE_BLOCK_INVALID_FREE_SPACE;
483 fprintf(stderr, "leaf free space incorrect %llu %d\n",
484 (unsigned long long)btrfs_header_bytenr(buf),
485 btrfs_leaf_free_space(root, buf));
486 goto fail;
487 }
488
489 if (nritems == 0)
490 return BTRFS_TREE_BLOCK_CLEAN;
491
492 btrfs_item_key(buf, &key, 0);
493 if (parent_key && parent_key->type &&
494 memcmp(parent_key, &key, sizeof(key))) {
495 ret = BTRFS_TREE_BLOCK_INVALID_PARENT_KEY;
496 fprintf(stderr, "leaf parent key incorrect %llu\n",
497 (unsigned long long)btrfs_header_bytenr(buf));
498 goto fail;
499 }
500 for (i = 0; nritems > 1 && i < nritems - 1; i++) {
501 btrfs_item_key(buf, &key, i);
502 btrfs_item_key_to_cpu(buf, &cpukey, i + 1);
503 if (btrfs_comp_keys(&key, &cpukey) >= 0) {
504 ret = BTRFS_TREE_BLOCK_BAD_KEY_ORDER;
505 fprintf(stderr, "bad key ordering %d %d\n", i, i+1);
506 goto fail;
507 }
508 if (btrfs_item_offset_nr(buf, i) !=
509 btrfs_item_end_nr(buf, i + 1)) {
510 ret = BTRFS_TREE_BLOCK_INVALID_OFFSETS;
511 fprintf(stderr, "incorrect offsets %u %u\n",
512 btrfs_item_offset_nr(buf, i),
513 btrfs_item_end_nr(buf, i + 1));
514 goto fail;
515 }
516 if (i == 0 && btrfs_item_end_nr(buf, i) !=
517 BTRFS_LEAF_DATA_SIZE(root)) {
518 ret = BTRFS_TREE_BLOCK_INVALID_OFFSETS;
519 fprintf(stderr, "bad item end %u wanted %u\n",
520 btrfs_item_end_nr(buf, i),
521 (unsigned)BTRFS_LEAF_DATA_SIZE(root));
522 goto fail;
523 }
524 }
525
526 for (i = 0; i < nritems; i++) {
527 if (btrfs_item_end_nr(buf, i) > BTRFS_LEAF_DATA_SIZE(root)) {
528 btrfs_item_key(buf, &key, 0);
529 btrfs_print_key(&key);
530 fflush(stdout);
531 ret = BTRFS_TREE_BLOCK_INVALID_OFFSETS;
532 fprintf(stderr, "slot end outside of leaf %llu > %llu\n",
533 (unsigned long long)btrfs_item_end_nr(buf, i),
534 (unsigned long long)BTRFS_LEAF_DATA_SIZE(root));
535 goto fail;
536 }
537 }
538
539 return BTRFS_TREE_BLOCK_CLEAN;
540 fail:
541 if (btrfs_header_owner(buf) == BTRFS_EXTENT_TREE_OBJECTID) {
542 if (parent_key)
543 btrfs_disk_key_to_cpu(&cpukey, parent_key);
544 else
545 btrfs_item_key_to_cpu(buf, &cpukey, 0);
546
547 btrfs_add_corrupt_extent_record(root->fs_info, &cpukey,
548 buf->start, buf->len, 0);
549 }
550 return ret;
551 }
552
553 static int noinline check_block(struct btrfs_root *root,
554 struct btrfs_path *path, int level)
555 {
556 struct btrfs_disk_key key;
557 struct btrfs_disk_key *key_ptr = NULL;
558 struct extent_buffer *parent;
559 enum btrfs_tree_block_status ret;
560
561 if (path->skip_check_block)
562 return 0;
563 if (path->nodes[level + 1]) {
564 parent = path->nodes[level + 1];
565 btrfs_node_key(parent, &key, path->slots[level + 1]);
566 key_ptr = &key;
567 }
568 if (level == 0)
569 ret = btrfs_check_leaf(root, key_ptr, path->nodes[0]);
570 else
571 ret = btrfs_check_node(root, key_ptr, path->nodes[level]);
572 if (ret == BTRFS_TREE_BLOCK_CLEAN)
573 return 0;
574 return -EIO;
575 }
576
577 /*
578 * search for key in the extent_buffer. The items start at offset p,
579 * and they are item_size apart. There are 'max' items in p.
580 *
581 * the slot in the array is returned via slot, and it points to
582 * the place where you would insert key if it is not found in
583 * the array.
584 *
585 * slot may point to max if the key is bigger than all of the keys
586 */
587 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
588 int item_size, struct btrfs_key *key,
589 int max, int *slot)
590 {
591 int low = 0;
592 int high = max;
593 int mid;
594 int ret;
595 unsigned long offset;
596 struct btrfs_disk_key *tmp;
597
598 while(low < high) {
599 mid = (low + high) / 2;
600 offset = p + mid * item_size;
601
602 tmp = (struct btrfs_disk_key *)(eb->data + offset);
603 ret = btrfs_comp_keys(tmp, key);
604
605 if (ret < 0)
606 low = mid + 1;
607 else if (ret > 0)
608 high = mid;
609 else {
610 *slot = mid;
611 return 0;
612 }
613 }
614 *slot = low;
615 return 1;
616 }
617
618 /*
619 * simple bin_search frontend that does the right thing for
620 * leaves vs nodes
621 */
622 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
623 int level, int *slot)
624 {
625 if (level == 0)
626 return generic_bin_search(eb,
627 offsetof(struct btrfs_leaf, items),
628 sizeof(struct btrfs_item),
629 key, btrfs_header_nritems(eb),
630 slot);
631 else
632 return generic_bin_search(eb,
633 offsetof(struct btrfs_node, ptrs),
634 sizeof(struct btrfs_key_ptr),
635 key, btrfs_header_nritems(eb),
636 slot);
637 }
638
639 struct extent_buffer *read_node_slot(struct btrfs_root *root,
640 struct extent_buffer *parent, int slot)
641 {
642 int level = btrfs_header_level(parent);
643 if (slot < 0)
644 return NULL;
645 if (slot >= btrfs_header_nritems(parent))
646 return NULL;
647
648 if (level == 0)
649 return NULL;
650
651 return read_tree_block(root, btrfs_node_blockptr(parent, slot),
652 root->nodesize,
653 btrfs_node_ptr_generation(parent, slot));
654 }
655
656 static int balance_level(struct btrfs_trans_handle *trans,
657 struct btrfs_root *root,
658 struct btrfs_path *path, int level)
659 {
660 struct extent_buffer *right = NULL;
661 struct extent_buffer *mid;
662 struct extent_buffer *left = NULL;
663 struct extent_buffer *parent = NULL;
664 int ret = 0;
665 int wret;
666 int pslot;
667 int orig_slot = path->slots[level];
668 u64 orig_ptr;
669
670 if (level == 0)
671 return 0;
672
673 mid = path->nodes[level];
674 WARN_ON(btrfs_header_generation(mid) != trans->transid);
675
676 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
677
678 if (level < BTRFS_MAX_LEVEL - 1) {
679 parent = path->nodes[level + 1];
680 pslot = path->slots[level + 1];
681 }
682
683 /*
684 * deal with the case where there is only one pointer in the root
685 * by promoting the node below to a root
686 */
687 if (!parent) {
688 struct extent_buffer *child;
689
690 if (btrfs_header_nritems(mid) != 1)
691 return 0;
692
693 /* promote the child to a root */
694 child = read_node_slot(root, mid, 0);
695 BUG_ON(!extent_buffer_uptodate(child));
696 ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
697 BUG_ON(ret);
698
699 root->node = child;
700 add_root_to_dirty_list(root);
701 path->nodes[level] = NULL;
702 clean_tree_block(trans, root, mid);
703 wait_on_tree_block_writeback(root, mid);
704 /* once for the path */
705 free_extent_buffer(mid);
706
707 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
708 0, root->root_key.objectid,
709 level, 1);
710 /* once for the root ptr */
711 free_extent_buffer(mid);
712 return ret;
713 }
714 if (btrfs_header_nritems(mid) >
715 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
716 return 0;
717
718 left = read_node_slot(root, parent, pslot - 1);
719 if (extent_buffer_uptodate(left)) {
720 wret = btrfs_cow_block(trans, root, left,
721 parent, pslot - 1, &left);
722 if (wret) {
723 ret = wret;
724 goto enospc;
725 }
726 }
727 right = read_node_slot(root, parent, pslot + 1);
728 if (extent_buffer_uptodate(right)) {
729 wret = btrfs_cow_block(trans, root, right,
730 parent, pslot + 1, &right);
731 if (wret) {
732 ret = wret;
733 goto enospc;
734 }
735 }
736
737 /* first, try to make some room in the middle buffer */
738 if (left) {
739 orig_slot += btrfs_header_nritems(left);
740 wret = push_node_left(trans, root, left, mid, 1);
741 if (wret < 0)
742 ret = wret;
743 }
744
745 /*
746 * then try to empty the right most buffer into the middle
747 */
748 if (right) {
749 wret = push_node_left(trans, root, mid, right, 1);
750 if (wret < 0 && wret != -ENOSPC)
751 ret = wret;
752 if (btrfs_header_nritems(right) == 0) {
753 u64 bytenr = right->start;
754 u32 blocksize = right->len;
755
756 clean_tree_block(trans, root, right);
757 wait_on_tree_block_writeback(root, right);
758 free_extent_buffer(right);
759 right = NULL;
760 wret = btrfs_del_ptr(trans, root, path,
761 level + 1, pslot + 1);
762 if (wret)
763 ret = wret;
764 wret = btrfs_free_extent(trans, root, bytenr,
765 blocksize, 0,
766 root->root_key.objectid,
767 level, 0);
768 if (wret)
769 ret = wret;
770 } else {
771 struct btrfs_disk_key right_key;
772 btrfs_node_key(right, &right_key, 0);
773 btrfs_set_node_key(parent, &right_key, pslot + 1);
774 btrfs_mark_buffer_dirty(parent);
775 }
776 }
777 if (btrfs_header_nritems(mid) == 1) {
778 /*
779 * we're not allowed to leave a node with one item in the
780 * tree during a delete. A deletion from lower in the tree
781 * could try to delete the only pointer in this node.
782 * So, pull some keys from the left.
783 * There has to be a left pointer at this point because
784 * otherwise we would have pulled some pointers from the
785 * right
786 */
787 BUG_ON(!left);
788 wret = balance_node_right(trans, root, mid, left);
789 if (wret < 0) {
790 ret = wret;
791 goto enospc;
792 }
793 if (wret == 1) {
794 wret = push_node_left(trans, root, left, mid, 1);
795 if (wret < 0)
796 ret = wret;
797 }
798 BUG_ON(wret == 1);
799 }
800 if (btrfs_header_nritems(mid) == 0) {
801 /* we've managed to empty the middle node, drop it */
802 u64 bytenr = mid->start;
803 u32 blocksize = mid->len;
804 clean_tree_block(trans, root, mid);
805 wait_on_tree_block_writeback(root, mid);
806 free_extent_buffer(mid);
807 mid = NULL;
808 wret = btrfs_del_ptr(trans, root, path, level + 1, pslot);
809 if (wret)
810 ret = wret;
811 wret = btrfs_free_extent(trans, root, bytenr, blocksize,
812 0, root->root_key.objectid,
813 level, 0);
814 if (wret)
815 ret = wret;
816 } else {
817 /* update the parent key to reflect our changes */
818 struct btrfs_disk_key mid_key;
819 btrfs_node_key(mid, &mid_key, 0);
820 btrfs_set_node_key(parent, &mid_key, pslot);
821 btrfs_mark_buffer_dirty(parent);
822 }
823
824 /* update the path */
825 if (left) {
826 if (btrfs_header_nritems(left) > orig_slot) {
827 extent_buffer_get(left);
828 path->nodes[level] = left;
829 path->slots[level + 1] -= 1;
830 path->slots[level] = orig_slot;
831 if (mid)
832 free_extent_buffer(mid);
833 } else {
834 orig_slot -= btrfs_header_nritems(left);
835 path->slots[level] = orig_slot;
836 }
837 }
838 /* double check we haven't messed things up */
839 check_block(root, path, level);
840 if (orig_ptr !=
841 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
842 BUG();
843 enospc:
844 if (right)
845 free_extent_buffer(right);
846 if (left)
847 free_extent_buffer(left);
848 return ret;
849 }
850
851 /* returns zero if the push worked, non-zero otherwise */
852 static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
853 struct btrfs_root *root,
854 struct btrfs_path *path, int level)
855 {
856 struct extent_buffer *right = NULL;
857 struct extent_buffer *mid;
858 struct extent_buffer *left = NULL;
859 struct extent_buffer *parent = NULL;
860 int ret = 0;
861 int wret;
862 int pslot;
863 int orig_slot = path->slots[level];
864
865 if (level == 0)
866 return 1;
867
868 mid = path->nodes[level];
869 WARN_ON(btrfs_header_generation(mid) != trans->transid);
870
871 if (level < BTRFS_MAX_LEVEL - 1) {
872 parent = path->nodes[level + 1];
873 pslot = path->slots[level + 1];
874 }
875
876 if (!parent)
877 return 1;
878
879 left = read_node_slot(root, parent, pslot - 1);
880
881 /* first, try to make some room in the middle buffer */
882 if (extent_buffer_uptodate(left)) {
883 u32 left_nr;
884 left_nr = btrfs_header_nritems(left);
885 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
886 wret = 1;
887 } else {
888 ret = btrfs_cow_block(trans, root, left, parent,
889 pslot - 1, &left);
890 if (ret)
891 wret = 1;
892 else {
893 wret = push_node_left(trans, root,
894 left, mid, 0);
895 }
896 }
897 if (wret < 0)
898 ret = wret;
899 if (wret == 0) {
900 struct btrfs_disk_key disk_key;
901 orig_slot += left_nr;
902 btrfs_node_key(mid, &disk_key, 0);
903 btrfs_set_node_key(parent, &disk_key, pslot);
904 btrfs_mark_buffer_dirty(parent);
905 if (btrfs_header_nritems(left) > orig_slot) {
906 path->nodes[level] = left;
907 path->slots[level + 1] -= 1;
908 path->slots[level] = orig_slot;
909 free_extent_buffer(mid);
910 } else {
911 orig_slot -=
912 btrfs_header_nritems(left);
913 path->slots[level] = orig_slot;
914 free_extent_buffer(left);
915 }
916 return 0;
917 }
918 free_extent_buffer(left);
919 }
920 right= read_node_slot(root, parent, pslot + 1);
921
922 /*
923 * then try to empty the right most buffer into the middle
924 */
925 if (extent_buffer_uptodate(right)) {
926 u32 right_nr;
927 right_nr = btrfs_header_nritems(right);
928 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
929 wret = 1;
930 } else {
931 ret = btrfs_cow_block(trans, root, right,
932 parent, pslot + 1,
933 &right);
934 if (ret)
935 wret = 1;
936 else {
937 wret = balance_node_right(trans, root,
938 right, mid);
939 }
940 }
941 if (wret < 0)
942 ret = wret;
943 if (wret == 0) {
944 struct btrfs_disk_key disk_key;
945
946 btrfs_node_key(right, &disk_key, 0);
947 btrfs_set_node_key(parent, &disk_key, pslot + 1);
948 btrfs_mark_buffer_dirty(parent);
949
950 if (btrfs_header_nritems(mid) <= orig_slot) {
951 path->nodes[level] = right;
952 path->slots[level + 1] += 1;
953 path->slots[level] = orig_slot -
954 btrfs_header_nritems(mid);
955 free_extent_buffer(mid);
956 } else {
957 free_extent_buffer(right);
958 }
959 return 0;
960 }
961 free_extent_buffer(right);
962 }
963 return 1;
964 }
965
966 /*
967 * readahead one full node of leaves
968 */
969 void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
970 int level, int slot, u64 objectid)
971 {
972 struct extent_buffer *node;
973 struct btrfs_disk_key disk_key;
974 u32 nritems;
975 u64 search;
976 u64 lowest_read;
977 u64 highest_read;
978 u64 nread = 0;
979 int direction = path->reada;
980 struct extent_buffer *eb;
981 u32 nr;
982 u32 blocksize;
983 u32 nscan = 0;
984
985 if (level != 1)
986 return;
987
988 if (!path->nodes[level])
989 return;
990
991 node = path->nodes[level];
992 search = btrfs_node_blockptr(node, slot);
993 blocksize = root->nodesize;
994 eb = btrfs_find_tree_block(root, search, blocksize);
995 if (eb) {
996 free_extent_buffer(eb);
997 return;
998 }
999
1000 highest_read = search;
1001 lowest_read = search;
1002
1003 nritems = btrfs_header_nritems(node);
1004 nr = slot;
1005 while(1) {
1006 if (direction < 0) {
1007 if (nr == 0)
1008 break;
1009 nr--;
1010 } else if (direction > 0) {
1011 nr++;
1012 if (nr >= nritems)
1013 break;
1014 }
1015 if (path->reada < 0 && objectid) {
1016 btrfs_node_key(node, &disk_key, nr);
1017 if (btrfs_disk_key_objectid(&disk_key) != objectid)
1018 break;
1019 }
1020 search = btrfs_node_blockptr(node, nr);
1021 if ((search >= lowest_read && search <= highest_read) ||
1022 (search < lowest_read && lowest_read - search <= 32768) ||
1023 (search > highest_read && search - highest_read <= 32768)) {
1024 readahead_tree_block(root, search, blocksize,
1025 btrfs_node_ptr_generation(node, nr));
1026 nread += blocksize;
1027 }
1028 nscan++;
1029 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
1030 break;
1031 if(nread > (1024 * 1024) || nscan > 128)
1032 break;
1033
1034 if (search < lowest_read)
1035 lowest_read = search;
1036 if (search > highest_read)
1037 highest_read = search;
1038 }
1039 }
1040
1041 int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *found_path,
1042 u64 iobjectid, u64 ioff, u8 key_type,
1043 struct btrfs_key *found_key)
1044 {
1045 int ret;
1046 struct btrfs_key key;
1047 struct extent_buffer *eb;
1048 struct btrfs_path *path;
1049
1050 key.type = key_type;
1051 key.objectid = iobjectid;
1052 key.offset = ioff;
1053
1054 if (found_path == NULL) {
1055 path = btrfs_alloc_path();
1056 if (!path)
1057 return -ENOMEM;
1058 } else
1059 path = found_path;
1060
1061 ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
1062 if ((ret < 0) || (found_key == NULL))
1063 goto out;
1064
1065 eb = path->nodes[0];
1066 if (ret && path->slots[0] >= btrfs_header_nritems(eb)) {
1067 ret = btrfs_next_leaf(fs_root, path);
1068 if (ret)
1069 goto out;
1070 eb = path->nodes[0];
1071 }
1072
1073 btrfs_item_key_to_cpu(eb, found_key, path->slots[0]);
1074 if (found_key->type != key.type ||
1075 found_key->objectid != key.objectid) {
1076 ret = 1;
1077 goto out;
1078 }
1079
1080 out:
1081 if (path != found_path)
1082 btrfs_free_path(path);
1083 return ret;
1084 }
1085
1086 /*
1087 * look for key in the tree. path is filled in with nodes along the way
1088 * if key is found, we return zero and you can find the item in the leaf
1089 * level of the path (level 0)
1090 *
1091 * If the key isn't found, the path points to the slot where it should
1092 * be inserted, and 1 is returned. If there are other errors during the
1093 * search a negative error number is returned.
1094 *
1095 * if ins_len > 0, nodes and leaves will be split as we walk down the
1096 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
1097 * possible)
1098 */
1099 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
1100 *root, struct btrfs_key *key, struct btrfs_path *p, int
1101 ins_len, int cow)
1102 {
1103 struct extent_buffer *b;
1104 int slot;
1105 int ret;
1106 int level;
1107 int should_reada = p->reada;
1108 u8 lowest_level = 0;
1109
1110 lowest_level = p->lowest_level;
1111 WARN_ON(lowest_level && ins_len > 0);
1112 WARN_ON(p->nodes[0] != NULL);
1113 /*
1114 WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
1115 */
1116 again:
1117 b = root->node;
1118 extent_buffer_get(b);
1119 while (b) {
1120 level = btrfs_header_level(b);
1121 if (cow) {
1122 int wret;
1123 wret = btrfs_cow_block(trans, root, b,
1124 p->nodes[level + 1],
1125 p->slots[level + 1],
1126 &b);
1127 if (wret) {
1128 free_extent_buffer(b);
1129 return wret;
1130 }
1131 }
1132 BUG_ON(!cow && ins_len);
1133 if (level != btrfs_header_level(b))
1134 WARN_ON(1);
1135 level = btrfs_header_level(b);
1136 p->nodes[level] = b;
1137 ret = check_block(root, p, level);
1138 if (ret)
1139 return -1;
1140 ret = bin_search(b, key, level, &slot);
1141 if (level != 0) {
1142 if (ret && slot > 0)
1143 slot -= 1;
1144 p->slots[level] = slot;
1145 if ((p->search_for_split || ins_len > 0) &&
1146 btrfs_header_nritems(b) >=
1147 BTRFS_NODEPTRS_PER_BLOCK(root) - 3) {
1148 int sret = split_node(trans, root, p, level);
1149 BUG_ON(sret > 0);
1150 if (sret)
1151 return sret;
1152 b = p->nodes[level];
1153 slot = p->slots[level];
1154 } else if (ins_len < 0) {
1155 int sret = balance_level(trans, root, p,
1156 level);
1157 if (sret)
1158 return sret;
1159 b = p->nodes[level];
1160 if (!b) {
1161 btrfs_release_path(p);
1162 goto again;
1163 }
1164 slot = p->slots[level];
1165 BUG_ON(btrfs_header_nritems(b) == 1);
1166 }
1167 /* this is only true while dropping a snapshot */
1168 if (level == lowest_level)
1169 break;
1170
1171 if (should_reada)
1172 reada_for_search(root, p, level, slot,
1173 key->objectid);
1174
1175 b = read_node_slot(root, b, slot);
1176 if (!extent_buffer_uptodate(b))
1177 return -EIO;
1178 } else {
1179 p->slots[level] = slot;
1180 if (ins_len > 0 &&
1181 ins_len > btrfs_leaf_free_space(root, b)) {
1182 int sret = split_leaf(trans, root, key,
1183 p, ins_len, ret == 0);
1184 BUG_ON(sret > 0);
1185 if (sret)
1186 return sret;
1187 }
1188 return ret;
1189 }
1190 }
1191 return 1;
1192 }
1193
1194 /*
1195 * adjust the pointers going up the tree, starting at level
1196 * making sure the right key of each node is points to 'key'.
1197 * This is used after shifting pointers to the left, so it stops
1198 * fixing up pointers when a given leaf/node is not in slot 0 of the
1199 * higher levels
1200 */
1201 void btrfs_fixup_low_keys(struct btrfs_root *root, struct btrfs_path *path,
1202 struct btrfs_disk_key *key, int level)
1203 {
1204 int i;
1205 struct extent_buffer *t;
1206
1207 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1208 int tslot = path->slots[i];
1209 if (!path->nodes[i])
1210 break;
1211 t = path->nodes[i];
1212 btrfs_set_node_key(t, key, tslot);
1213 btrfs_mark_buffer_dirty(path->nodes[i]);
1214 if (tslot != 0)
1215 break;
1216 }
1217 }
1218
1219 /*
1220 * update item key.
1221 *
1222 * This function isn't completely safe. It's the caller's responsibility
1223 * that the new key won't break the order
1224 */
1225 int btrfs_set_item_key_safe(struct btrfs_root *root, struct btrfs_path *path,
1226 struct btrfs_key *new_key)
1227 {
1228 struct btrfs_disk_key disk_key;
1229 struct extent_buffer *eb;
1230 int slot;
1231
1232 eb = path->nodes[0];
1233 slot = path->slots[0];
1234 if (slot > 0) {
1235 btrfs_item_key(eb, &disk_key, slot - 1);
1236 if (btrfs_comp_keys(&disk_key, new_key) >= 0)
1237 return -1;
1238 }
1239 if (slot < btrfs_header_nritems(eb) - 1) {
1240 btrfs_item_key(eb, &disk_key, slot + 1);
1241 if (btrfs_comp_keys(&disk_key, new_key) <= 0)
1242 return -1;
1243 }
1244
1245 btrfs_cpu_key_to_disk(&disk_key, new_key);
1246 btrfs_set_item_key(eb, &disk_key, slot);
1247 btrfs_mark_buffer_dirty(eb);
1248 if (slot == 0)
1249 btrfs_fixup_low_keys(root, path, &disk_key, 1);
1250 return 0;
1251 }
1252
1253 /*
1254 * update an item key without the safety checks. This is meant to be called by
1255 * fsck only.
1256 */
1257 void btrfs_set_item_key_unsafe(struct btrfs_root *root,
1258 struct btrfs_path *path,
1259 struct btrfs_key *new_key)
1260 {
1261 struct btrfs_disk_key disk_key;
1262 struct extent_buffer *eb;
1263 int slot;
1264
1265 eb = path->nodes[0];
1266 slot = path->slots[0];
1267
1268 btrfs_cpu_key_to_disk(&disk_key, new_key);
1269 btrfs_set_item_key(eb, &disk_key, slot);
1270 btrfs_mark_buffer_dirty(eb);
1271 if (slot == 0)
1272 btrfs_fixup_low_keys(root, path, &disk_key, 1);
1273 }
1274
1275 /*
1276 * try to push data from one node into the next node left in the
1277 * tree.
1278 *
1279 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1280 * error, and > 0 if there was no room in the left hand block.
1281 */
1282 static int push_node_left(struct btrfs_trans_handle *trans,
1283 struct btrfs_root *root, struct extent_buffer *dst,
1284 struct extent_buffer *src, int empty)
1285 {
1286 int push_items = 0;
1287 int src_nritems;
1288 int dst_nritems;
1289 int ret = 0;
1290
1291 src_nritems = btrfs_header_nritems(src);
1292 dst_nritems = btrfs_header_nritems(dst);
1293 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1294 WARN_ON(btrfs_header_generation(src) != trans->transid);
1295 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1296
1297 if (!empty && src_nritems <= 8)
1298 return 1;
1299
1300 if (push_items <= 0) {
1301 return 1;
1302 }
1303
1304 if (empty) {
1305 push_items = min(src_nritems, push_items);
1306 if (push_items < src_nritems) {
1307 /* leave at least 8 pointers in the node if
1308 * we aren't going to empty it
1309 */
1310 if (src_nritems - push_items < 8) {
1311 if (push_items <= 8)
1312 return 1;
1313 push_items -= 8;
1314 }
1315 }
1316 } else
1317 push_items = min(src_nritems - 8, push_items);
1318
1319 copy_extent_buffer(dst, src,
1320 btrfs_node_key_ptr_offset(dst_nritems),
1321 btrfs_node_key_ptr_offset(0),
1322 push_items * sizeof(struct btrfs_key_ptr));
1323
1324 if (push_items < src_nritems) {
1325 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1326 btrfs_node_key_ptr_offset(push_items),
1327 (src_nritems - push_items) *
1328 sizeof(struct btrfs_key_ptr));
1329 }
1330 btrfs_set_header_nritems(src, src_nritems - push_items);
1331 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1332 btrfs_mark_buffer_dirty(src);
1333 btrfs_mark_buffer_dirty(dst);
1334
1335 return ret;
1336 }
1337
1338 /*
1339 * try to push data from one node into the next node right in the
1340 * tree.
1341 *
1342 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1343 * error, and > 0 if there was no room in the right hand block.
1344 *
1345 * this will only push up to 1/2 the contents of the left node over
1346 */
1347 static int balance_node_right(struct btrfs_trans_handle *trans,
1348 struct btrfs_root *root,
1349 struct extent_buffer *dst,
1350 struct extent_buffer *src)
1351 {
1352 int push_items = 0;
1353 int max_push;
1354 int src_nritems;
1355 int dst_nritems;
1356 int ret = 0;
1357
1358 WARN_ON(btrfs_header_generation(src) != trans->transid);
1359 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1360
1361 src_nritems = btrfs_header_nritems(src);
1362 dst_nritems = btrfs_header_nritems(dst);
1363 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1364 if (push_items <= 0) {
1365 return 1;
1366 }
1367
1368 if (src_nritems < 4) {
1369 return 1;
1370 }
1371
1372 max_push = src_nritems / 2 + 1;
1373 /* don't try to empty the node */
1374 if (max_push >= src_nritems) {
1375 return 1;
1376 }
1377
1378 if (max_push < push_items)
1379 push_items = max_push;
1380
1381 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1382 btrfs_node_key_ptr_offset(0),
1383 (dst_nritems) *
1384 sizeof(struct btrfs_key_ptr));
1385
1386 copy_extent_buffer(dst, src,
1387 btrfs_node_key_ptr_offset(0),
1388 btrfs_node_key_ptr_offset(src_nritems - push_items),
1389 push_items * sizeof(struct btrfs_key_ptr));
1390
1391 btrfs_set_header_nritems(src, src_nritems - push_items);
1392 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1393
1394 btrfs_mark_buffer_dirty(src);
1395 btrfs_mark_buffer_dirty(dst);
1396
1397 return ret;
1398 }
1399
1400 /*
1401 * helper function to insert a new root level in the tree.
1402 * A new node is allocated, and a single item is inserted to
1403 * point to the existing root
1404 *
1405 * returns zero on success or < 0 on failure.
1406 */
1407 static int noinline insert_new_root(struct btrfs_trans_handle *trans,
1408 struct btrfs_root *root,
1409 struct btrfs_path *path, int level)
1410 {
1411 u64 lower_gen;
1412 struct extent_buffer *lower;
1413 struct extent_buffer *c;
1414 struct extent_buffer *old;
1415 struct btrfs_disk_key lower_key;
1416
1417 BUG_ON(path->nodes[level]);
1418 BUG_ON(path->nodes[level-1] != root->node);
1419
1420 lower = path->nodes[level-1];
1421 if (level == 1)
1422 btrfs_item_key(lower, &lower_key, 0);
1423 else
1424 btrfs_node_key(lower, &lower_key, 0);
1425
1426 c = btrfs_alloc_free_block(trans, root, root->nodesize,
1427 root->root_key.objectid, &lower_key,
1428 level, root->node->start, 0);
1429
1430 if (IS_ERR(c))
1431 return PTR_ERR(c);
1432
1433 memset_extent_buffer(c, 0, 0, sizeof(struct btrfs_header));
1434 btrfs_set_header_nritems(c, 1);
1435 btrfs_set_header_level(c, level);
1436 btrfs_set_header_bytenr(c, c->start);
1437 btrfs_set_header_generation(c, trans->transid);
1438 btrfs_set_header_backref_rev(c, BTRFS_MIXED_BACKREF_REV);
1439 btrfs_set_header_owner(c, root->root_key.objectid);
1440
1441 write_extent_buffer(c, root->fs_info->fsid,
1442 btrfs_header_fsid(), BTRFS_FSID_SIZE);
1443
1444 write_extent_buffer(c, root->fs_info->chunk_tree_uuid,
1445 btrfs_header_chunk_tree_uuid(c),
1446 BTRFS_UUID_SIZE);
1447
1448 btrfs_set_node_key(c, &lower_key, 0);
1449 btrfs_set_node_blockptr(c, 0, lower->start);
1450 lower_gen = btrfs_header_generation(lower);
1451 WARN_ON(lower_gen != trans->transid);
1452
1453 btrfs_set_node_ptr_generation(c, 0, lower_gen);
1454
1455 btrfs_mark_buffer_dirty(c);
1456
1457 old = root->node;
1458 root->node = c;
1459
1460 /* the super has an extra ref to root->node */
1461 free_extent_buffer(old);
1462
1463 add_root_to_dirty_list(root);
1464 extent_buffer_get(c);
1465 path->nodes[level] = c;
1466 path->slots[level] = 0;
1467 return 0;
1468 }
1469
1470 /*
1471 * worker function to insert a single pointer in a node.
1472 * the node should have enough room for the pointer already
1473 *
1474 * slot and level indicate where you want the key to go, and
1475 * blocknr is the block the key points to.
1476 *
1477 * returns zero on success and < 0 on any error
1478 */
1479 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1480 *root, struct btrfs_path *path, struct btrfs_disk_key
1481 *key, u64 bytenr, int slot, int level)
1482 {
1483 struct extent_buffer *lower;
1484 int nritems;
1485
1486 BUG_ON(!path->nodes[level]);
1487 lower = path->nodes[level];
1488 nritems = btrfs_header_nritems(lower);
1489 if (slot > nritems)
1490 BUG();
1491 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1492 BUG();
1493 if (slot != nritems) {
1494 memmove_extent_buffer(lower,
1495 btrfs_node_key_ptr_offset(slot + 1),
1496 btrfs_node_key_ptr_offset(slot),
1497 (nritems - slot) * sizeof(struct btrfs_key_ptr));
1498 }
1499 btrfs_set_node_key(lower, key, slot);
1500 btrfs_set_node_blockptr(lower, slot, bytenr);
1501 WARN_ON(trans->transid == 0);
1502 btrfs_set_node_ptr_generation(lower, slot, trans->transid);
1503 btrfs_set_header_nritems(lower, nritems + 1);
1504 btrfs_mark_buffer_dirty(lower);
1505 return 0;
1506 }
1507
1508 /*
1509 * split the node at the specified level in path in two.
1510 * The path is corrected to point to the appropriate node after the split
1511 *
1512 * Before splitting this tries to make some room in the node by pushing
1513 * left and right, if either one works, it returns right away.
1514 *
1515 * returns 0 on success and < 0 on failure
1516 */
1517 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1518 *root, struct btrfs_path *path, int level)
1519 {
1520 struct extent_buffer *c;
1521 struct extent_buffer *split;
1522 struct btrfs_disk_key disk_key;
1523 int mid;
1524 int ret;
1525 int wret;
1526 u32 c_nritems;
1527
1528 c = path->nodes[level];
1529 WARN_ON(btrfs_header_generation(c) != trans->transid);
1530 if (c == root->node) {
1531 /* trying to split the root, lets make a new one */
1532 ret = insert_new_root(trans, root, path, level + 1);
1533 if (ret)
1534 return ret;
1535 } else {
1536 ret = push_nodes_for_insert(trans, root, path, level);
1537 c = path->nodes[level];
1538 if (!ret && btrfs_header_nritems(c) <
1539 BTRFS_NODEPTRS_PER_BLOCK(root) - 3)
1540 return 0;
1541 if (ret < 0)
1542 return ret;
1543 }
1544
1545 c_nritems = btrfs_header_nritems(c);
1546 mid = (c_nritems + 1) / 2;
1547 btrfs_node_key(c, &disk_key, mid);
1548
1549 split = btrfs_alloc_free_block(trans, root, root->nodesize,
1550 root->root_key.objectid,
1551 &disk_key, level, c->start, 0);
1552 if (IS_ERR(split))
1553 return PTR_ERR(split);
1554
1555 memset_extent_buffer(split, 0, 0, sizeof(struct btrfs_header));
1556 btrfs_set_header_level(split, btrfs_header_level(c));
1557 btrfs_set_header_bytenr(split, split->start);
1558 btrfs_set_header_generation(split, trans->transid);
1559 btrfs_set_header_backref_rev(split, BTRFS_MIXED_BACKREF_REV);
1560 btrfs_set_header_owner(split, root->root_key.objectid);
1561 write_extent_buffer(split, root->fs_info->fsid,
1562 btrfs_header_fsid(), BTRFS_FSID_SIZE);
1563 write_extent_buffer(split, root->fs_info->chunk_tree_uuid,
1564 btrfs_header_chunk_tree_uuid(split),
1565 BTRFS_UUID_SIZE);
1566
1567
1568 copy_extent_buffer(split, c,
1569 btrfs_node_key_ptr_offset(0),
1570 btrfs_node_key_ptr_offset(mid),
1571 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1572 btrfs_set_header_nritems(split, c_nritems - mid);
1573 btrfs_set_header_nritems(c, mid);
1574 ret = 0;
1575
1576 btrfs_mark_buffer_dirty(c);
1577 btrfs_mark_buffer_dirty(split);
1578
1579 wret = insert_ptr(trans, root, path, &disk_key, split->start,
1580 path->slots[level + 1] + 1,
1581 level + 1);
1582 if (wret)
1583 ret = wret;
1584
1585 if (path->slots[level] >= mid) {
1586 path->slots[level] -= mid;
1587 free_extent_buffer(c);
1588 path->nodes[level] = split;
1589 path->slots[level + 1] += 1;
1590 } else {
1591 free_extent_buffer(split);
1592 }
1593 return ret;
1594 }
1595
1596 /*
1597 * how many bytes are required to store the items in a leaf. start
1598 * and nr indicate which items in the leaf to check. This totals up the
1599 * space used both by the item structs and the item data
1600 */
1601 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1602 {
1603 int data_len;
1604 int nritems = btrfs_header_nritems(l);
1605 int end = min(nritems, start + nr) - 1;
1606
1607 if (!nr)
1608 return 0;
1609 data_len = btrfs_item_end_nr(l, start);
1610 data_len = data_len - btrfs_item_offset_nr(l, end);
1611 data_len += sizeof(struct btrfs_item) * nr;
1612 WARN_ON(data_len < 0);
1613 return data_len;
1614 }
1615
1616 /*
1617 * The space between the end of the leaf items and
1618 * the start of the leaf data. IOW, how much room
1619 * the leaf has left for both items and data
1620 */
1621 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1622 {
1623 u32 nodesize = (root ? BTRFS_LEAF_DATA_SIZE(root) : leaf->len);
1624 int nritems = btrfs_header_nritems(leaf);
1625 int ret;
1626 ret = nodesize - leaf_space_used(leaf, 0, nritems);
1627 if (ret < 0) {
1628 printk("leaf free space ret %d, leaf data size %u, used %d nritems %d\n",
1629 ret, nodesize, leaf_space_used(leaf, 0, nritems),
1630 nritems);
1631 }
1632 return ret;
1633 }
1634
1635 /*
1636 * push some data in the path leaf to the right, trying to free up at
1637 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1638 *
1639 * returns 1 if the push failed because the other node didn't have enough
1640 * room, 0 if everything worked out and < 0 if there were major errors.
1641 */
1642 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1643 *root, struct btrfs_path *path, int data_size,
1644 int empty)
1645 {
1646 struct extent_buffer *left = path->nodes[0];
1647 struct extent_buffer *right;
1648 struct extent_buffer *upper;
1649 struct btrfs_disk_key disk_key;
1650 int slot;
1651 u32 i;
1652 int free_space;
1653 int push_space = 0;
1654 int push_items = 0;
1655 struct btrfs_item *item;
1656 u32 left_nritems;
1657 u32 nr;
1658 u32 right_nritems;
1659 u32 data_end;
1660 u32 this_item_size;
1661 int ret;
1662
1663 slot = path->slots[1];
1664 if (!path->nodes[1]) {
1665 return 1;
1666 }
1667 upper = path->nodes[1];
1668 if (slot >= btrfs_header_nritems(upper) - 1)
1669 return 1;
1670
1671 right = read_node_slot(root, upper, slot + 1);
1672 if (!extent_buffer_uptodate(right)) {
1673 if (IS_ERR(right))
1674 return PTR_ERR(right);
1675 return -EIO;
1676 }
1677 free_space = btrfs_leaf_free_space(root, right);
1678 if (free_space < data_size) {
1679 free_extent_buffer(right);
1680 return 1;
1681 }
1682
1683 /* cow and double check */
1684 ret = btrfs_cow_block(trans, root, right, upper,
1685 slot + 1, &right);
1686 if (ret) {
1687 free_extent_buffer(right);
1688 return 1;
1689 }
1690 free_space = btrfs_leaf_free_space(root, right);
1691 if (free_space < data_size) {
1692 free_extent_buffer(right);
1693 return 1;
1694 }
1695
1696 left_nritems = btrfs_header_nritems(left);
1697 if (left_nritems == 0) {
1698 free_extent_buffer(right);
1699 return 1;
1700 }
1701
1702 if (empty)
1703 nr = 0;
1704 else
1705 nr = 1;
1706
1707 i = left_nritems - 1;
1708 while (i >= nr) {
1709 item = btrfs_item_nr(i);
1710
1711 if (path->slots[0] == i)
1712 push_space += data_size + sizeof(*item);
1713
1714 this_item_size = btrfs_item_size(left, item);
1715 if (this_item_size + sizeof(*item) + push_space > free_space)
1716 break;
1717 push_items++;
1718 push_space += this_item_size + sizeof(*item);
1719 if (i == 0)
1720 break;
1721 i--;
1722 }
1723
1724 if (push_items == 0) {
1725 free_extent_buffer(right);
1726 return 1;
1727 }
1728
1729 if (!empty && push_items == left_nritems)
1730 WARN_ON(1);
1731
1732 /* push left to right */
1733 right_nritems = btrfs_header_nritems(right);
1734
1735 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1736 push_space -= leaf_data_end(root, left);
1737
1738 /* make room in the right data area */
1739 data_end = leaf_data_end(root, right);
1740 memmove_extent_buffer(right,
1741 btrfs_leaf_data(right) + data_end - push_space,
1742 btrfs_leaf_data(right) + data_end,
1743 BTRFS_LEAF_DATA_SIZE(root) - data_end);
1744
1745 /* copy from the left data area */
1746 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1747 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1748 btrfs_leaf_data(left) + leaf_data_end(root, left),
1749 push_space);
1750
1751 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1752 btrfs_item_nr_offset(0),
1753 right_nritems * sizeof(struct btrfs_item));
1754
1755 /* copy the items from left to right */
1756 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1757 btrfs_item_nr_offset(left_nritems - push_items),
1758 push_items * sizeof(struct btrfs_item));
1759
1760 /* update the item pointers */
1761 right_nritems += push_items;
1762 btrfs_set_header_nritems(right, right_nritems);
1763 push_space = BTRFS_LEAF_DATA_SIZE(root);
1764 for (i = 0; i < right_nritems; i++) {
1765 item = btrfs_item_nr(i);
1766 push_space -= btrfs_item_size(right, item);
1767 btrfs_set_item_offset(right, item, push_space);
1768 }
1769
1770 left_nritems -= push_items;
1771 btrfs_set_header_nritems(left, left_nritems);
1772
1773 if (left_nritems)
1774 btrfs_mark_buffer_dirty(left);
1775 btrfs_mark_buffer_dirty(right);
1776
1777 btrfs_item_key(right, &disk_key, 0);
1778 btrfs_set_node_key(upper, &disk_key, slot + 1);
1779 btrfs_mark_buffer_dirty(upper);
1780
1781 /* then fixup the leaf pointer in the path */
1782 if (path->slots[0] >= left_nritems) {
1783 path->slots[0] -= left_nritems;
1784 free_extent_buffer(path->nodes[0]);
1785 path->nodes[0] = right;
1786 path->slots[1] += 1;
1787 } else {
1788 free_extent_buffer(right);
1789 }
1790 return 0;
1791 }
1792 /*
1793 * push some data in the path leaf to the left, trying to free up at
1794 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1795 */
1796 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1797 *root, struct btrfs_path *path, int data_size,
1798 int empty)
1799 {
1800 struct btrfs_disk_key disk_key;
1801 struct extent_buffer *right = path->nodes[0];
1802 struct extent_buffer *left;
1803 int slot;
1804 int i;
1805 int free_space;
1806 int push_space = 0;
1807 int push_items = 0;
1808 struct btrfs_item *item;
1809 u32 old_left_nritems;
1810 u32 right_nritems;
1811 u32 nr;
1812 int ret = 0;
1813 u32 this_item_size;
1814 u32 old_left_item_size;
1815
1816 slot = path->slots[1];
1817 if (slot == 0)
1818 return 1;
1819 if (!path->nodes[1])
1820 return 1;
1821
1822 right_nritems = btrfs_header_nritems(right);
1823 if (right_nritems == 0) {
1824 return 1;
1825 }
1826
1827 left = read_node_slot(root, path->nodes[1], slot - 1);
1828 free_space = btrfs_leaf_free_space(root, left);
1829 if (free_space < data_size) {
1830 free_extent_buffer(left);
1831 return 1;
1832 }
1833
1834 /* cow and double check */
1835 ret = btrfs_cow_block(trans, root, left,
1836 path->nodes[1], slot - 1, &left);
1837 if (ret) {
1838 /* we hit -ENOSPC, but it isn't fatal here */
1839 free_extent_buffer(left);
1840 return 1;
1841 }
1842
1843 free_space = btrfs_leaf_free_space(root, left);
1844 if (free_space < data_size) {
1845 free_extent_buffer(left);
1846 return 1;
1847 }
1848
1849 if (empty)
1850 nr = right_nritems;
1851 else
1852 nr = right_nritems - 1;
1853
1854 for (i = 0; i < nr; i++) {
1855 item = btrfs_item_nr(i);
1856
1857 if (path->slots[0] == i)
1858 push_space += data_size + sizeof(*item);
1859
1860 this_item_size = btrfs_item_size(right, item);
1861 if (this_item_size + sizeof(*item) + push_space > free_space)
1862 break;
1863
1864 push_items++;
1865 push_space += this_item_size + sizeof(*item);
1866 }
1867
1868 if (push_items == 0) {
1869 free_extent_buffer(left);
1870 return 1;
1871 }
1872 if (!empty && push_items == btrfs_header_nritems(right))
1873 WARN_ON(1);
1874
1875 /* push data from right to left */
1876 copy_extent_buffer(left, right,
1877 btrfs_item_nr_offset(btrfs_header_nritems(left)),
1878 btrfs_item_nr_offset(0),
1879 push_items * sizeof(struct btrfs_item));
1880
1881 push_space = BTRFS_LEAF_DATA_SIZE(root) -
1882 btrfs_item_offset_nr(right, push_items -1);
1883
1884 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
1885 leaf_data_end(root, left) - push_space,
1886 btrfs_leaf_data(right) +
1887 btrfs_item_offset_nr(right, push_items - 1),
1888 push_space);
1889 old_left_nritems = btrfs_header_nritems(left);
1890 BUG_ON(old_left_nritems == 0);
1891
1892 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
1893 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1894 u32 ioff;
1895
1896 item = btrfs_item_nr(i);
1897 ioff = btrfs_item_offset(left, item);
1898 btrfs_set_item_offset(left, item,
1899 ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
1900 }
1901 btrfs_set_header_nritems(left, old_left_nritems + push_items);
1902
1903 /* fixup right node */
1904 if (push_items > right_nritems) {
1905 printk("push items %d nr %u\n", push_items, right_nritems);
1906 WARN_ON(1);
1907 }
1908
1909 if (push_items < right_nritems) {
1910 push_space = btrfs_item_offset_nr(right, push_items - 1) -
1911 leaf_data_end(root, right);
1912 memmove_extent_buffer(right, btrfs_leaf_data(right) +
1913 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1914 btrfs_leaf_data(right) +
1915 leaf_data_end(root, right), push_space);
1916
1917 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
1918 btrfs_item_nr_offset(push_items),
1919 (btrfs_header_nritems(right) - push_items) *
1920 sizeof(struct btrfs_item));
1921 }
1922 right_nritems -= push_items;
1923 btrfs_set_header_nritems(right, right_nritems);
1924 push_space = BTRFS_LEAF_DATA_SIZE(root);
1925 for (i = 0; i < right_nritems; i++) {
1926 item = btrfs_item_nr(i);
1927 push_space = push_space - btrfs_item_size(right, item);
1928 btrfs_set_item_offset(right, item, push_space);
1929 }
1930
1931 btrfs_mark_buffer_dirty(left);
1932 if (right_nritems)
1933 btrfs_mark_buffer_dirty(right);
1934
1935 btrfs_item_key(right, &disk_key, 0);
1936 btrfs_fixup_low_keys(root, path, &disk_key, 1);
1937
1938 /* then fixup the leaf pointer in the path */
1939 if (path->slots[0] < push_items) {
1940 path->slots[0] += old_left_nritems;
1941 free_extent_buffer(path->nodes[0]);
1942 path->nodes[0] = left;
1943 path->slots[1] -= 1;
1944 } else {
1945 free_extent_buffer(left);
1946 path->slots[0] -= push_items;
1947 }
1948 BUG_ON(path->slots[0] < 0);
1949 return ret;
1950 }
1951
1952 /*
1953 * split the path's leaf in two, making sure there is at least data_size
1954 * available for the resulting leaf level of the path.
1955 *
1956 * returns 0 if all went well and < 0 on failure.
1957 */
1958 static noinline int copy_for_split(struct btrfs_trans_handle *trans,
1959 struct btrfs_root *root,
1960 struct btrfs_path *path,
1961 struct extent_buffer *l,
1962 struct extent_buffer *right,
1963 int slot, int mid, int nritems)
1964 {
1965 int data_copy_size;
1966 int rt_data_off;
1967 int i;
1968 int ret = 0;
1969 int wret;
1970 struct btrfs_disk_key disk_key;
1971
1972 nritems = nritems - mid;
1973 btrfs_set_header_nritems(right, nritems);
1974 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
1975
1976 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
1977 btrfs_item_nr_offset(mid),
1978 nritems * sizeof(struct btrfs_item));
1979
1980 copy_extent_buffer(right, l,
1981 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
1982 data_copy_size, btrfs_leaf_data(l) +
1983 leaf_data_end(root, l), data_copy_size);
1984
1985 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
1986 btrfs_item_end_nr(l, mid);
1987
1988 for (i = 0; i < nritems; i++) {
1989 struct btrfs_item *item = btrfs_item_nr(i);
1990 u32 ioff = btrfs_item_offset(right, item);
1991 btrfs_set_item_offset(right, item, ioff + rt_data_off);
1992 }
1993
1994 btrfs_set_header_nritems(l, mid);
1995 ret = 0;
1996 btrfs_item_key(right, &disk_key, 0);
1997 wret = insert_ptr(trans, root, path, &disk_key, right->start,
1998 path->slots[1] + 1, 1);
1999 if (wret)
2000 ret = wret;
2001
2002 btrfs_mark_buffer_dirty(right);
2003 btrfs_mark_buffer_dirty(l);
2004 BUG_ON(path->slots[0] != slot);
2005
2006 if (mid <= slot) {
2007 free_extent_buffer(path->nodes[0]);
2008 path->nodes[0] = right;
2009 path->slots[0] -= mid;
2010 path->slots[1] += 1;
2011 } else {
2012 free_extent_buffer(right);
2013 }
2014
2015 BUG_ON(path->slots[0] < 0);
2016
2017 return ret;
2018 }
2019
2020 /*
2021 * split the path's leaf in two, making sure there is at least data_size
2022 * available for the resulting leaf level of the path.
2023 *
2024 * returns 0 if all went well and < 0 on failure.
2025 */
2026 static noinline int split_leaf(struct btrfs_trans_handle *trans,
2027 struct btrfs_root *root,
2028 struct btrfs_key *ins_key,
2029 struct btrfs_path *path, int data_size,
2030 int extend)
2031 {
2032 struct btrfs_disk_key disk_key;
2033 struct extent_buffer *l;
2034 u32 nritems;
2035 int mid;
2036 int slot;
2037 struct extent_buffer *right;
2038 int ret = 0;
2039 int wret;
2040 int split;
2041 int num_doubles = 0;
2042
2043 l = path->nodes[0];
2044 slot = path->slots[0];
2045 if (extend && data_size + btrfs_item_size_nr(l, slot) +
2046 sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root))
2047 return -EOVERFLOW;
2048
2049 /* first try to make some room by pushing left and right */
2050 if (data_size && ins_key->type != BTRFS_DIR_ITEM_KEY) {
2051 wret = push_leaf_right(trans, root, path, data_size, 0);
2052 if (wret < 0)
2053 return wret;
2054 if (wret) {
2055 wret = push_leaf_left(trans, root, path, data_size, 0);
2056 if (wret < 0)
2057 return wret;
2058 }
2059 l = path->nodes[0];
2060
2061 /* did the pushes work? */
2062 if (btrfs_leaf_free_space(root, l) >= data_size)
2063 return 0;
2064 }
2065
2066 if (!path->nodes[1]) {
2067 ret = insert_new_root(trans, root, path, 1);
2068 if (ret)
2069 return ret;
2070 }
2071 again:
2072 split = 1;
2073 l = path->nodes[0];
2074 slot = path->slots[0];
2075 nritems = btrfs_header_nritems(l);
2076 mid = (nritems + 1) / 2;
2077
2078 if (mid <= slot) {
2079 if (nritems == 1 ||
2080 leaf_space_used(l, mid, nritems - mid) + data_size >
2081 BTRFS_LEAF_DATA_SIZE(root)) {
2082 if (slot >= nritems) {
2083 split = 0;
2084 } else {
2085 mid = slot;
2086 if (mid != nritems &&
2087 leaf_space_used(l, mid, nritems - mid) +
2088 data_size > BTRFS_LEAF_DATA_SIZE(root)) {
2089 split = 2;
2090 }
2091 }
2092 }
2093 } else {
2094 if (leaf_space_used(l, 0, mid) + data_size >
2095 BTRFS_LEAF_DATA_SIZE(root)) {
2096 if (!extend && data_size && slot == 0) {
2097 split = 0;
2098 } else if ((extend || !data_size) && slot == 0) {
2099 mid = 1;
2100 } else {
2101 mid = slot;
2102 if (mid != nritems &&
2103 leaf_space_used(l, mid, nritems - mid) +
2104 data_size > BTRFS_LEAF_DATA_SIZE(root)) {
2105 split = 2 ;
2106 }
2107 }
2108 }
2109 }
2110
2111 if (split == 0)
2112 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2113 else
2114 btrfs_item_key(l, &disk_key, mid);
2115
2116 right = btrfs_alloc_free_block(trans, root, root->nodesize,
2117 root->root_key.objectid,
2118 &disk_key, 0, l->start, 0);
2119 if (IS_ERR(right)) {
2120 BUG_ON(1);
2121 return PTR_ERR(right);
2122 }
2123
2124 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
2125 btrfs_set_header_bytenr(right, right->start);
2126 btrfs_set_header_generation(right, trans->transid);
2127 btrfs_set_header_backref_rev(right, BTRFS_MIXED_BACKREF_REV);
2128 btrfs_set_header_owner(right, root->root_key.objectid);
2129 btrfs_set_header_level(right, 0);
2130 write_extent_buffer(right, root->fs_info->fsid,
2131 btrfs_header_fsid(), BTRFS_FSID_SIZE);
2132
2133 write_extent_buffer(right, root->fs_info->chunk_tree_uuid,
2134 btrfs_header_chunk_tree_uuid(right),
2135 BTRFS_UUID_SIZE);
2136
2137 if (split == 0) {
2138 if (mid <= slot) {
2139 btrfs_set_header_nritems(right, 0);
2140 wret = insert_ptr(trans, root, path,
2141 &disk_key, right->start,
2142 path->slots[1] + 1, 1);
2143 if (wret)
2144 ret = wret;
2145
2146 free_extent_buffer(path->nodes[0]);
2147 path->nodes[0] = right;
2148 path->slots[0] = 0;
2149 path->slots[1] += 1;
2150 } else {
2151 btrfs_set_header_nritems(right, 0);
2152 wret = insert_ptr(trans, root, path,
2153 &disk_key,
2154 right->start,
2155 path->slots[1], 1);
2156 if (wret)
2157 ret = wret;
2158 free_extent_buffer(path->nodes[0]);
2159 path->nodes[0] = right;
2160 path->slots[0] = 0;
2161 if (path->slots[1] == 0) {
2162 btrfs_fixup_low_keys(root, path,
2163 &disk_key, 1);
2164 }
2165 }
2166 btrfs_mark_buffer_dirty(right);
2167 return ret;
2168 }
2169
2170 ret = copy_for_split(trans, root, path, l, right, slot, mid, nritems);
2171 BUG_ON(ret);
2172
2173 if (split == 2) {
2174 BUG_ON(num_doubles != 0);
2175 num_doubles++;
2176 goto again;
2177 }
2178
2179 return ret;
2180 }
2181
2182 /*
2183 * This function splits a single item into two items,
2184 * giving 'new_key' to the new item and splitting the
2185 * old one at split_offset (from the start of the item).
2186 *
2187 * The path may be released by this operation. After
2188 * the split, the path is pointing to the old item. The
2189 * new item is going to be in the same node as the old one.
2190 *
2191 * Note, the item being split must be smaller enough to live alone on
2192 * a tree block with room for one extra struct btrfs_item
2193 *
2194 * This allows us to split the item in place, keeping a lock on the
2195 * leaf the entire time.
2196 */
2197 int btrfs_split_item(struct btrfs_trans_handle *trans,
2198 struct btrfs_root *root,
2199 struct btrfs_path *path,
2200 struct btrfs_key *new_key,
2201 unsigned long split_offset)
2202 {
2203 u32 item_size;
2204 struct extent_buffer *leaf;
2205 struct btrfs_key orig_key;
2206 struct btrfs_item *item;
2207 struct btrfs_item *new_item;
2208 int ret = 0;
2209 int slot;
2210 u32 nritems;
2211 u32 orig_offset;
2212 struct btrfs_disk_key disk_key;
2213 char *buf;
2214
2215 leaf = path->nodes[0];
2216 btrfs_item_key_to_cpu(leaf, &orig_key, path->slots[0]);
2217 if (btrfs_leaf_free_space(root, leaf) >= sizeof(struct btrfs_item))
2218 goto split;
2219
2220 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2221 btrfs_release_path(path);
2222
2223 path->search_for_split = 1;
2224
2225 ret = btrfs_search_slot(trans, root, &orig_key, path, 0, 1);
2226 path->search_for_split = 0;
2227
2228 /* if our item isn't there or got smaller, return now */
2229 if (ret != 0 || item_size != btrfs_item_size_nr(path->nodes[0],
2230 path->slots[0])) {
2231 return -EAGAIN;
2232 }
2233
2234 ret = split_leaf(trans, root, &orig_key, path, 0, 0);
2235 BUG_ON(ret);
2236
2237 BUG_ON(btrfs_leaf_free_space(root, leaf) < sizeof(struct btrfs_item));
2238 leaf = path->nodes[0];
2239
2240 split:
2241 item = btrfs_item_nr(path->slots[0]);
2242 orig_offset = btrfs_item_offset(leaf, item);
2243 item_size = btrfs_item_size(leaf, item);
2244
2245
2246 buf = kmalloc(item_size, GFP_NOFS);
2247 BUG_ON(!buf);
2248 read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf,
2249 path->slots[0]), item_size);
2250 slot = path->slots[0] + 1;
2251 leaf = path->nodes[0];
2252
2253 nritems = btrfs_header_nritems(leaf);
2254
2255 if (slot != nritems) {
2256 /* shift the items */
2257 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1),
2258 btrfs_item_nr_offset(slot),
2259 (nritems - slot) * sizeof(struct btrfs_item));
2260
2261 }
2262
2263 btrfs_cpu_key_to_disk(&disk_key, new_key);
2264 btrfs_set_item_key(leaf, &disk_key, slot);
2265
2266 new_item = btrfs_item_nr(slot);
2267
2268 btrfs_set_item_offset(leaf, new_item, orig_offset);
2269 btrfs_set_item_size(leaf, new_item, item_size - split_offset);
2270
2271 btrfs_set_item_offset(leaf, item,
2272 orig_offset + item_size - split_offset);
2273 btrfs_set_item_size(leaf, item, split_offset);
2274
2275 btrfs_set_header_nritems(leaf, nritems + 1);
2276
2277 /* write the data for the start of the original item */
2278 write_extent_buffer(leaf, buf,
2279 btrfs_item_ptr_offset(leaf, path->slots[0]),
2280 split_offset);
2281
2282 /* write the data for the new item */
2283 write_extent_buffer(leaf, buf + split_offset,
2284 btrfs_item_ptr_offset(leaf, slot),
2285 item_size - split_offset);
2286 btrfs_mark_buffer_dirty(leaf);
2287
2288 ret = 0;
2289 if (btrfs_leaf_free_space(root, leaf) < 0) {
2290 btrfs_print_leaf(root, leaf);
2291 BUG();
2292 }
2293 kfree(buf);
2294 return ret;
2295 }
2296
2297 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
2298 struct btrfs_root *root,
2299 struct btrfs_path *path,
2300 u32 new_size, int from_end)
2301 {
2302 int ret = 0;
2303 int slot;
2304 struct extent_buffer *leaf;
2305 struct btrfs_item *item;
2306 u32 nritems;
2307 unsigned int data_end;
2308 unsigned int old_data_start;
2309 unsigned int old_size;
2310 unsigned int size_diff;
2311 int i;
2312
2313 leaf = path->nodes[0];
2314 slot = path->slots[0];
2315
2316 old_size = btrfs_item_size_nr(leaf, slot);
2317 if (old_size == new_size)
2318 return 0;
2319
2320 nritems = btrfs_header_nritems(leaf);
2321 data_end = leaf_data_end(root, leaf);
2322
2323 old_data_start = btrfs_item_offset_nr(leaf, slot);
2324
2325 size_diff = old_size - new_size;
2326
2327 BUG_ON(slot < 0);
2328 BUG_ON(slot >= nritems);
2329
2330 /*
2331 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2332 */
2333 /* first correct the data pointers */
2334 for (i = slot; i < nritems; i++) {
2335 u32 ioff;
2336 item = btrfs_item_nr(i);
2337 ioff = btrfs_item_offset(leaf, item);
2338 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2339 }
2340
2341 /* shift the data */
2342 if (from_end) {
2343 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2344 data_end + size_diff, btrfs_leaf_data(leaf) +
2345 data_end, old_data_start + new_size - data_end);
2346 } else {
2347 struct btrfs_disk_key disk_key;
2348 u64 offset;
2349
2350 btrfs_item_key(leaf, &disk_key, slot);
2351
2352 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2353 unsigned long ptr;
2354 struct btrfs_file_extent_item *fi;
2355
2356 fi = btrfs_item_ptr(leaf, slot,
2357 struct btrfs_file_extent_item);
2358 fi = (struct btrfs_file_extent_item *)(
2359 (unsigned long)fi - size_diff);
2360
2361 if (btrfs_file_extent_type(leaf, fi) ==
2362 BTRFS_FILE_EXTENT_INLINE) {
2363 ptr = btrfs_item_ptr_offset(leaf, slot);
2364 memmove_extent_buffer(leaf, ptr,
2365 (unsigned long)fi,
2366 offsetof(struct btrfs_file_extent_item,
2367 disk_bytenr));
2368 }
2369 }
2370
2371 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2372 data_end + size_diff, btrfs_leaf_data(leaf) +
2373 data_end, old_data_start - data_end);
2374
2375 offset = btrfs_disk_key_offset(&disk_key);
2376 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2377 btrfs_set_item_key(leaf, &disk_key, slot);
2378 if (slot == 0)
2379 btrfs_fixup_low_keys(root, path, &disk_key, 1);
2380 }
2381
2382 item = btrfs_item_nr(slot);
2383 btrfs_set_item_size(leaf, item, new_size);
2384 btrfs_mark_buffer_dirty(leaf);
2385
2386 ret = 0;
2387 if (btrfs_leaf_free_space(root, leaf) < 0) {
2388 btrfs_print_leaf(root, leaf);
2389 BUG();
2390 }
2391 return ret;
2392 }
2393
2394 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2395 struct btrfs_root *root, struct btrfs_path *path,
2396 u32 data_size)
2397 {
2398 int ret = 0;
2399 int slot;
2400 struct extent_buffer *leaf;
2401 struct btrfs_item *item;
2402 u32 nritems;
2403 unsigned int data_end;
2404 unsigned int old_data;
2405 unsigned int old_size;
2406 int i;
2407
2408 leaf = path->nodes[0];
2409
2410 nritems = btrfs_header_nritems(leaf);
2411 data_end = leaf_data_end(root, leaf);
2412
2413 if (btrfs_leaf_free_space(root, leaf) < data_size) {
2414 btrfs_print_leaf(root, leaf);
2415 BUG();
2416 }
2417 slot = path->slots[0];
2418 old_data = btrfs_item_end_nr(leaf, slot);
2419
2420 BUG_ON(slot < 0);
2421 if (slot >= nritems) {
2422 btrfs_print_leaf(root, leaf);
2423 printk("slot %d too large, nritems %d\n", slot, nritems);
2424 BUG_ON(1);
2425 }
2426
2427 /*
2428 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2429 */
2430 /* first correct the data pointers */
2431 for (i = slot; i < nritems; i++) {
2432 u32 ioff;
2433 item = btrfs_item_nr(i);
2434 ioff = btrfs_item_offset(leaf, item);
2435 btrfs_set_item_offset(leaf, item, ioff - data_size);
2436 }
2437
2438 /* shift the data */
2439 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2440 data_end - data_size, btrfs_leaf_data(leaf) +
2441 data_end, old_data - data_end);
2442
2443 data_end = old_data;
2444 old_size = btrfs_item_size_nr(leaf, slot);
2445 item = btrfs_item_nr(slot);
2446 btrfs_set_item_size(leaf, item, old_size + data_size);
2447 btrfs_mark_buffer_dirty(leaf);
2448
2449 ret = 0;
2450 if (btrfs_leaf_free_space(root, leaf) < 0) {
2451 btrfs_print_leaf(root, leaf);
2452 BUG();
2453 }
2454 return ret;
2455 }
2456
2457 /*
2458 * Given a key and some data, insert an item into the tree.
2459 * This does all the path init required, making room in the tree if needed.
2460 */
2461 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
2462 struct btrfs_root *root,
2463 struct btrfs_path *path,
2464 struct btrfs_key *cpu_key, u32 *data_size,
2465 int nr)
2466 {
2467 struct extent_buffer *leaf;
2468 struct btrfs_item *item;
2469 int ret = 0;
2470 int slot;
2471 int i;
2472 u32 nritems;
2473 u32 total_size = 0;
2474 u32 total_data = 0;
2475 unsigned int data_end;
2476 struct btrfs_disk_key disk_key;
2477
2478 for (i = 0; i < nr; i++) {
2479 total_data += data_size[i];
2480 }
2481
2482 /* create a root if there isn't one */
2483 if (!root->node)
2484 BUG();
2485
2486 total_size = total_data + nr * sizeof(struct btrfs_item);
2487 ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
2488 if (ret == 0) {
2489 return -EEXIST;
2490 }
2491 if (ret < 0)
2492 goto out;
2493
2494 leaf = path->nodes[0];
2495
2496 nritems = btrfs_header_nritems(leaf);
2497 data_end = leaf_data_end(root, leaf);
2498
2499 if (btrfs_leaf_free_space(root, leaf) < total_size) {
2500 btrfs_print_leaf(root, leaf);
2501 printk("not enough freespace need %u have %d\n",
2502 total_size, btrfs_leaf_free_space(root, leaf));
2503 BUG();
2504 }
2505
2506 slot = path->slots[0];
2507 BUG_ON(slot < 0);
2508
2509 if (slot != nritems) {
2510 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2511
2512 if (old_data < data_end) {
2513 btrfs_print_leaf(root, leaf);
2514 printk("slot %d old_data %d data_end %d\n",
2515 slot, old_data, data_end);
2516 BUG_ON(1);
2517 }
2518 /*
2519 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2520 */
2521 /* first correct the data pointers */
2522 for (i = slot; i < nritems; i++) {
2523 u32 ioff;
2524
2525 item = btrfs_item_nr(i);
2526 ioff = btrfs_item_offset(leaf, item);
2527 btrfs_set_item_offset(leaf, item, ioff - total_data);
2528 }
2529
2530 /* shift the items */
2531 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
2532 btrfs_item_nr_offset(slot),
2533 (nritems - slot) * sizeof(struct btrfs_item));
2534
2535 /* shift the data */
2536 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2537 data_end - total_data, btrfs_leaf_data(leaf) +
2538 data_end, old_data - data_end);
2539 data_end = old_data;
2540 }
2541
2542 /* setup the item for the new data */
2543 for (i = 0; i < nr; i++) {
2544 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
2545 btrfs_set_item_key(leaf, &disk_key, slot + i);
2546 item = btrfs_item_nr(slot + i);
2547 btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
2548 data_end -= data_size[i];
2549 btrfs_set_item_size(leaf, item, data_size[i]);
2550 }
2551 btrfs_set_header_nritems(leaf, nritems + nr);
2552 btrfs_mark_buffer_dirty(leaf);
2553
2554 ret = 0;
2555 if (slot == 0) {
2556 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2557 btrfs_fixup_low_keys(root, path, &disk_key, 1);
2558 }
2559
2560 if (btrfs_leaf_free_space(root, leaf) < 0) {
2561 btrfs_print_leaf(root, leaf);
2562 BUG();
2563 }
2564
2565 out:
2566 return ret;
2567 }
2568
2569 /*
2570 * Given a key and some data, insert an item into the tree.
2571 * This does all the path init required, making room in the tree if needed.
2572 */
2573 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2574 *root, struct btrfs_key *cpu_key, void *data, u32
2575 data_size)
2576 {
2577 int ret = 0;
2578 struct btrfs_path *path;
2579 struct extent_buffer *leaf;
2580 unsigned long ptr;
2581
2582 path = btrfs_alloc_path();
2583 BUG_ON(!path);
2584 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2585 if (!ret) {
2586 leaf = path->nodes[0];
2587 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2588 write_extent_buffer(leaf, data, ptr, data_size);
2589 btrfs_mark_buffer_dirty(leaf);
2590 }
2591 btrfs_free_path(path);
2592 return ret;
2593 }
2594
2595 /*
2596 * delete the pointer from a given node.
2597 *
2598 * If the delete empties a node, the node is removed from the tree,
2599 * continuing all the way the root if required. The root is converted into
2600 * a leaf if all the nodes are emptied.
2601 */
2602 int btrfs_del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2603 struct btrfs_path *path, int level, int slot)
2604 {
2605 struct extent_buffer *parent = path->nodes[level];
2606 u32 nritems;
2607 int ret = 0;
2608
2609 nritems = btrfs_header_nritems(parent);
2610 if (slot != nritems -1) {
2611 memmove_extent_buffer(parent,
2612 btrfs_node_key_ptr_offset(slot),
2613 btrfs_node_key_ptr_offset(slot + 1),
2614 sizeof(struct btrfs_key_ptr) *
2615 (nritems - slot - 1));
2616 }
2617 nritems--;
2618 btrfs_set_header_nritems(parent, nritems);
2619 if (nritems == 0 && parent == root->node) {
2620 BUG_ON(btrfs_header_level(root->node) != 1);
2621 /* just turn the root into a leaf and break */
2622 btrfs_set_header_level(root->node, 0);
2623 } else if (slot == 0) {
2624 struct btrfs_disk_key disk_key;
2625
2626 btrfs_node_key(parent, &disk_key, 0);
2627 btrfs_fixup_low_keys(root, path, &disk_key, level + 1);
2628 }
2629 btrfs_mark_buffer_dirty(parent);
2630 return ret;
2631 }
2632
2633 /*
2634 * a helper function to delete the leaf pointed to by path->slots[1] and
2635 * path->nodes[1].
2636 *
2637 * This deletes the pointer in path->nodes[1] and frees the leaf
2638 * block extent. zero is returned if it all worked out, < 0 otherwise.
2639 *
2640 * The path must have already been setup for deleting the leaf, including
2641 * all the proper balancing. path->nodes[1] must be locked.
2642 */
2643 static noinline int btrfs_del_leaf(struct btrfs_trans_handle *trans,
2644 struct btrfs_root *root,
2645 struct btrfs_path *path,
2646 struct extent_buffer *leaf)
2647 {
2648 int ret;
2649
2650 WARN_ON(btrfs_header_generation(leaf) != trans->transid);
2651 ret = btrfs_del_ptr(trans, root, path, 1, path->slots[1]);
2652 if (ret)
2653 return ret;
2654
2655 ret = btrfs_free_extent(trans, root, leaf->start, leaf->len,
2656 0, root->root_key.objectid, 0, 0);
2657 return ret;
2658 }
2659
2660 /*
2661 * delete the item at the leaf level in path. If that empties
2662 * the leaf, remove it from the tree
2663 */
2664 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2665 struct btrfs_path *path, int slot, int nr)
2666 {
2667 struct extent_buffer *leaf;
2668 struct btrfs_item *item;
2669 int last_off;
2670 int dsize = 0;
2671 int ret = 0;
2672 int wret;
2673 int i;
2674 u32 nritems;
2675
2676 leaf = path->nodes[0];
2677 last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
2678
2679 for (i = 0; i < nr; i++)
2680 dsize += btrfs_item_size_nr(leaf, slot + i);
2681
2682 nritems = btrfs_header_nritems(leaf);
2683
2684 if (slot + nr != nritems) {
2685 int data_end = leaf_data_end(root, leaf);
2686
2687 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2688 data_end + dsize,
2689 btrfs_leaf_data(leaf) + data_end,
2690 last_off - data_end);
2691
2692 for (i = slot + nr; i < nritems; i++) {
2693 u32 ioff;
2694
2695 item = btrfs_item_nr(i);
2696 ioff = btrfs_item_offset(leaf, item);
2697 btrfs_set_item_offset(leaf, item, ioff + dsize);
2698 }
2699
2700 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2701 btrfs_item_nr_offset(slot + nr),
2702 sizeof(struct btrfs_item) *
2703 (nritems - slot - nr));
2704 }
2705 btrfs_set_header_nritems(leaf, nritems - nr);
2706 nritems -= nr;
2707
2708 /* delete the leaf if we've emptied it */
2709 if (nritems == 0) {
2710 if (leaf == root->node) {
2711 btrfs_set_header_level(leaf, 0);
2712 } else {
2713 clean_tree_block(trans, root, leaf);
2714 wait_on_tree_block_writeback(root, leaf);
2715
2716 wret = btrfs_del_leaf(trans, root, path, leaf);
2717 BUG_ON(ret);
2718 if (wret)
2719 ret = wret;
2720 }
2721 } else {
2722 int used = leaf_space_used(leaf, 0, nritems);
2723 if (slot == 0) {
2724 struct btrfs_disk_key disk_key;
2725
2726 btrfs_item_key(leaf, &disk_key, 0);
2727 btrfs_fixup_low_keys(root, path, &disk_key, 1);
2728 }
2729
2730 /* delete the leaf if it is mostly empty */
2731 if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
2732 /* push_leaf_left fixes the path.
2733 * make sure the path still points to our leaf
2734 * for possible call to del_ptr below
2735 */
2736 slot = path->slots[1];
2737 extent_buffer_get(leaf);
2738
2739 wret = push_leaf_left(trans, root, path, 1, 1);
2740 if (wret < 0 && wret != -ENOSPC)
2741 ret = wret;
2742
2743 if (path->nodes[0] == leaf &&
2744 btrfs_header_nritems(leaf)) {
2745 wret = push_leaf_right(trans, root, path, 1, 1);
2746 if (wret < 0 && wret != -ENOSPC)
2747 ret = wret;
2748 }
2749
2750 if (btrfs_header_nritems(leaf) == 0) {
2751 clean_tree_block(trans, root, leaf);
2752 wait_on_tree_block_writeback(root, leaf);
2753
2754 path->slots[1] = slot;
2755 ret = btrfs_del_leaf(trans, root, path, leaf);
2756 BUG_ON(ret);
2757 free_extent_buffer(leaf);
2758
2759 } else {
2760 btrfs_mark_buffer_dirty(leaf);
2761 free_extent_buffer(leaf);
2762 }
2763 } else {
2764 btrfs_mark_buffer_dirty(leaf);
2765 }
2766 }
2767 return ret;
2768 }
2769
2770 /*
2771 * walk up the tree as far as required to find the previous leaf.
2772 * returns 0 if it found something or 1 if there are no lesser leaves.
2773 * returns < 0 on io errors.
2774 */
2775 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
2776 {
2777 int slot;
2778 int level = 1;
2779 struct extent_buffer *c;
2780 struct extent_buffer *next = NULL;
2781
2782 while(level < BTRFS_MAX_LEVEL) {
2783 if (!path->nodes[level])
2784 return 1;
2785
2786 slot = path->slots[level];
2787 c = path->nodes[level];
2788 if (slot == 0) {
2789 level++;
2790 if (level == BTRFS_MAX_LEVEL)
2791 return 1;
2792 continue;
2793 }
2794 slot--;
2795
2796 next = read_node_slot(root, c, slot);
2797 if (!extent_buffer_uptodate(next)) {
2798 if (IS_ERR(next))
2799 return PTR_ERR(next);
2800 return -EIO;
2801 }
2802 break;
2803 }
2804 path->slots[level] = slot;
2805 while(1) {
2806 level--;
2807 c = path->nodes[level];
2808 free_extent_buffer(c);
2809 slot = btrfs_header_nritems(next);
2810 if (slot != 0)
2811 slot--;
2812 path->nodes[level] = next;
2813 path->slots[level] = slot;
2814 if (!level)
2815 break;
2816 next = read_node_slot(root, next, slot);
2817 if (!extent_buffer_uptodate(next)) {
2818 if (IS_ERR(next))
2819 return PTR_ERR(next);
2820 return -EIO;
2821 }
2822 }
2823 return 0;
2824 }
2825
2826 /*
2827 * walk up the tree as far as required to find the next leaf.
2828 * returns 0 if it found something or 1 if there are no greater leaves.
2829 * returns < 0 on io errors.
2830 */
2831 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2832 {
2833 int slot;
2834 int level = 1;
2835 struct extent_buffer *c;
2836 struct extent_buffer *next = NULL;
2837
2838 while(level < BTRFS_MAX_LEVEL) {
2839 if (!path->nodes[level])
2840 return 1;
2841
2842 slot = path->slots[level] + 1;
2843 c = path->nodes[level];
2844 if (slot >= btrfs_header_nritems(c)) {
2845 level++;
2846 if (level == BTRFS_MAX_LEVEL)
2847 return 1;
2848 continue;
2849 }
2850
2851 if (path->reada)
2852 reada_for_search(root, path, level, slot, 0);
2853
2854 next = read_node_slot(root, c, slot);
2855 if (!extent_buffer_uptodate(next))
2856 return -EIO;
2857 break;
2858 }
2859 path->slots[level] = slot;
2860 while(1) {
2861 level--;
2862 c = path->nodes[level];
2863 free_extent_buffer(c);
2864 path->nodes[level] = next;
2865 path->slots[level] = 0;
2866 if (!level)
2867 break;
2868 if (path->reada)
2869 reada_for_search(root, path, level, 0, 0);
2870 next = read_node_slot(root, next, 0);
2871 if (!extent_buffer_uptodate(next))
2872 return -EIO;
2873 }
2874 return 0;
2875 }
2876
2877 int btrfs_previous_item(struct btrfs_root *root,
2878 struct btrfs_path *path, u64 min_objectid,
2879 int type)
2880 {
2881 struct btrfs_key found_key;
2882 struct extent_buffer *leaf;
2883 u32 nritems;
2884 int ret;
2885
2886 while(1) {
2887 if (path->slots[0] == 0) {
2888 ret = btrfs_prev_leaf(root, path);
2889 if (ret != 0)
2890 return ret;
2891 } else {
2892 path->slots[0]--;
2893 }
2894 leaf = path->nodes[0];
2895 nritems = btrfs_header_nritems(leaf);
2896 if (nritems == 0)
2897 return 1;
2898 if (path->slots[0] == nritems)
2899 path->slots[0]--;
2900
2901 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2902 if (found_key.objectid < min_objectid)
2903 break;
2904 if (found_key.type == type)
2905 return 0;
2906 if (found_key.objectid == min_objectid &&
2907 found_key.type < type)
2908 break;
2909 }
2910 return 1;
2911 }
2912
2913 /*
2914 * search in extent tree to find a previous Metadata/Data extent item with
2915 * min objecitd.
2916 *
2917 * returns 0 if something is found, 1 if nothing was found and < 0 on error
2918 */
2919 int btrfs_previous_extent_item(struct btrfs_root *root,
2920 struct btrfs_path *path, u64 min_objectid)
2921 {
2922 struct btrfs_key found_key;
2923 struct extent_buffer *leaf;
2924 u32 nritems;
2925 int ret;
2926
2927 while (1) {
2928 if (path->slots[0] == 0) {
2929 ret = btrfs_prev_leaf(root, path);
2930 if (ret != 0)
2931 return ret;
2932 } else {
2933 path->slots[0]--;
2934 }
2935 leaf = path->nodes[0];
2936 nritems = btrfs_header_nritems(leaf);
2937 if (nritems == 0)
2938 return 1;
2939 if (path->slots[0] == nritems)
2940 path->slots[0]--;
2941
2942 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2943 if (found_key.objectid < min_objectid)
2944 break;
2945 if (found_key.type == BTRFS_EXTENT_ITEM_KEY ||
2946 found_key.type == BTRFS_METADATA_ITEM_KEY)
2947 return 0;
2948 if (found_key.objectid == min_objectid &&
2949 found_key.type < BTRFS_EXTENT_ITEM_KEY)
2950 break;
2951 }
2952 return 1;
2953 }
2954
2955 /*
2956 * Search in extent tree to found next meta/data extent
2957 * Caller needs to check for no-hole or skinny metadata features.
2958 */
2959 int btrfs_next_extent_item(struct btrfs_root *root,
2960 struct btrfs_path *path, u64 max_objectid)
2961 {
2962 struct btrfs_key found_key;
2963 int ret;
2964
2965 while (1) {
2966 ret = btrfs_next_item(root, path);
2967 if (ret)
2968 return ret;
2969 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
2970 path->slots[0]);
2971 if (found_key.objectid > max_objectid)
2972 return 1;
2973 if (found_key.type == BTRFS_EXTENT_ITEM_KEY ||
2974 found_key.type == BTRFS_METADATA_ITEM_KEY)
2975 return 0;
2976 }
2977 }
(deprecated) Btrfs progs developments and patch integration