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Btrfs: Replace the big fs_mutex with a collection of other locks
[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 #include "locking.h"
25
26 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
27 *root, struct btrfs_path *path, int level);
28 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
29 *root, struct btrfs_key *ins_key,
30 struct btrfs_path *path, int data_size, int extend);
31 static int push_node_left(struct btrfs_trans_handle *trans,
32 struct btrfs_root *root, struct extent_buffer *dst,
33 struct extent_buffer *src, int empty);
34 static int balance_node_right(struct btrfs_trans_handle *trans,
35 struct btrfs_root *root,
36 struct extent_buffer *dst_buf,
37 struct extent_buffer *src_buf);
38 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
39 struct btrfs_path *path, int level, int slot);
40
41 inline void btrfs_init_path(struct btrfs_path *p)
42 {
43 memset(p, 0, sizeof(*p));
44 }
45
46 struct btrfs_path *btrfs_alloc_path(void)
47 {
48 struct btrfs_path *path;
49 path = kmem_cache_alloc(btrfs_path_cachep, GFP_NOFS);
50 if (path) {
51 btrfs_init_path(path);
52 path->reada = 1;
53 }
54 return path;
55 }
56
57 void btrfs_free_path(struct btrfs_path *p)
58 {
59 btrfs_release_path(NULL, p);
60 kmem_cache_free(btrfs_path_cachep, p);
61 }
62
63 void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
64 {
65 int i;
66 int skip = p->skip_locking;
67 int keep = p->keep_locks;
68
69 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
70 if (!p->nodes[i])
71 continue;
72 if (p->locks[i]) {
73 btrfs_tree_unlock(p->nodes[i]);
74 p->locks[i] = 0;
75 }
76 free_extent_buffer(p->nodes[i]);
77 }
78 memset(p, 0, sizeof(*p));
79 p->skip_locking = skip;
80 p->keep_locks = keep;
81 }
82
83 struct extent_buffer *btrfs_root_node(struct btrfs_root *root)
84 {
85 struct extent_buffer *eb;
86 spin_lock(&root->node_lock);
87 eb = root->node;
88 extent_buffer_get(eb);
89 spin_unlock(&root->node_lock);
90 return eb;
91 }
92
93 struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root)
94 {
95 struct extent_buffer *eb;
96
97 while(1) {
98 eb = btrfs_root_node(root);
99 btrfs_tree_lock(eb);
100
101 spin_lock(&root->node_lock);
102 if (eb == root->node) {
103 spin_unlock(&root->node_lock);
104 break;
105 }
106 spin_unlock(&root->node_lock);
107
108 btrfs_tree_unlock(eb);
109 free_extent_buffer(eb);
110 }
111 return eb;
112 }
113
114 static void add_root_to_dirty_list(struct btrfs_root *root)
115 {
116 if (root->track_dirty && list_empty(&root->dirty_list)) {
117 list_add(&root->dirty_list,
118 &root->fs_info->dirty_cowonly_roots);
119 }
120 }
121
122 int btrfs_copy_root(struct btrfs_trans_handle *trans,
123 struct btrfs_root *root,
124 struct extent_buffer *buf,
125 struct extent_buffer **cow_ret, u64 new_root_objectid)
126 {
127 struct extent_buffer *cow;
128 u32 nritems;
129 int ret = 0;
130 int level;
131 struct btrfs_key first_key;
132 struct btrfs_root *new_root;
133
134 new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
135 if (!new_root)
136 return -ENOMEM;
137
138 memcpy(new_root, root, sizeof(*new_root));
139 new_root->root_key.objectid = new_root_objectid;
140
141 WARN_ON(root->ref_cows && trans->transid !=
142 root->fs_info->running_transaction->transid);
143 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
144
145 level = btrfs_header_level(buf);
146 nritems = btrfs_header_nritems(buf);
147 if (nritems) {
148 if (level == 0)
149 btrfs_item_key_to_cpu(buf, &first_key, 0);
150 else
151 btrfs_node_key_to_cpu(buf, &first_key, 0);
152 } else {
153 first_key.objectid = 0;
154 }
155 cow = btrfs_alloc_free_block(trans, new_root, buf->len,
156 new_root_objectid,
157 trans->transid, first_key.objectid,
158 level, buf->start, 0);
159 if (IS_ERR(cow)) {
160 kfree(new_root);
161 return PTR_ERR(cow);
162 }
163
164 copy_extent_buffer(cow, buf, 0, 0, cow->len);
165 btrfs_set_header_bytenr(cow, cow->start);
166 btrfs_set_header_generation(cow, trans->transid);
167 btrfs_set_header_owner(cow, new_root_objectid);
168 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
169
170 WARN_ON(btrfs_header_generation(buf) > trans->transid);
171 ret = btrfs_inc_ref(trans, new_root, buf);
172 kfree(new_root);
173
174 if (ret)
175 return ret;
176
177 btrfs_mark_buffer_dirty(cow);
178 *cow_ret = cow;
179 return 0;
180 }
181
182 int __btrfs_cow_block(struct btrfs_trans_handle *trans,
183 struct btrfs_root *root,
184 struct extent_buffer *buf,
185 struct extent_buffer *parent, int parent_slot,
186 struct extent_buffer **cow_ret,
187 u64 search_start, u64 empty_size)
188 {
189 u64 root_gen;
190 struct extent_buffer *cow;
191 u32 nritems;
192 int ret = 0;
193 int different_trans = 0;
194 int level;
195 int unlock_orig = 0;
196 struct btrfs_key first_key;
197
198 if (*cow_ret == buf)
199 unlock_orig = 1;
200
201 WARN_ON(!btrfs_tree_locked(buf));
202
203 if (root->ref_cows) {
204 root_gen = trans->transid;
205 } else {
206 root_gen = 0;
207 }
208 WARN_ON(root->ref_cows && trans->transid !=
209 root->fs_info->running_transaction->transid);
210 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
211
212 level = btrfs_header_level(buf);
213 nritems = btrfs_header_nritems(buf);
214 if (nritems) {
215 if (level == 0)
216 btrfs_item_key_to_cpu(buf, &first_key, 0);
217 else
218 btrfs_node_key_to_cpu(buf, &first_key, 0);
219 } else {
220 first_key.objectid = 0;
221 }
222 cow = btrfs_alloc_free_block(trans, root, buf->len,
223 root->root_key.objectid,
224 root_gen, first_key.objectid, level,
225 search_start, empty_size);
226 if (IS_ERR(cow))
227 return PTR_ERR(cow);
228
229 copy_extent_buffer(cow, buf, 0, 0, cow->len);
230 btrfs_set_header_bytenr(cow, cow->start);
231 btrfs_set_header_generation(cow, trans->transid);
232 btrfs_set_header_owner(cow, root->root_key.objectid);
233 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
234
235 WARN_ON(btrfs_header_generation(buf) > trans->transid);
236 if (btrfs_header_generation(buf) != trans->transid) {
237 different_trans = 1;
238 ret = btrfs_inc_ref(trans, root, buf);
239 if (ret)
240 return ret;
241 } else {
242 clean_tree_block(trans, root, buf);
243 }
244
245 if (buf == root->node) {
246 WARN_ON(parent && parent != buf);
247 root_gen = btrfs_header_generation(buf);
248
249 spin_lock(&root->node_lock);
250 root->node = cow;
251 extent_buffer_get(cow);
252 spin_unlock(&root->node_lock);
253
254 if (buf != root->commit_root) {
255 btrfs_free_extent(trans, root, buf->start,
256 buf->len, root->root_key.objectid,
257 root_gen, 0, 0, 1);
258 }
259 free_extent_buffer(buf);
260 add_root_to_dirty_list(root);
261 } else {
262 root_gen = btrfs_header_generation(parent);
263 btrfs_set_node_blockptr(parent, parent_slot,
264 cow->start);
265 WARN_ON(trans->transid == 0);
266 btrfs_set_node_ptr_generation(parent, parent_slot,
267 trans->transid);
268 btrfs_mark_buffer_dirty(parent);
269 WARN_ON(btrfs_header_generation(parent) != trans->transid);
270 btrfs_free_extent(trans, root, buf->start, buf->len,
271 btrfs_header_owner(parent), root_gen,
272 0, 0, 1);
273 }
274 if (unlock_orig)
275 btrfs_tree_unlock(buf);
276 free_extent_buffer(buf);
277 btrfs_mark_buffer_dirty(cow);
278 *cow_ret = cow;
279 return 0;
280 }
281
282 int btrfs_cow_block(struct btrfs_trans_handle *trans,
283 struct btrfs_root *root, struct extent_buffer *buf,
284 struct extent_buffer *parent, int parent_slot,
285 struct extent_buffer **cow_ret)
286 {
287 u64 search_start;
288 u64 header_trans;
289 int ret;
290
291 if (trans->transaction != root->fs_info->running_transaction) {
292 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
293 root->fs_info->running_transaction->transid);
294 WARN_ON(1);
295 }
296 if (trans->transid != root->fs_info->generation) {
297 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
298 root->fs_info->generation);
299 WARN_ON(1);
300 }
301
302 header_trans = btrfs_header_generation(buf);
303 spin_lock(&root->fs_info->hash_lock);
304 if (header_trans == trans->transid &&
305 !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
306 *cow_ret = buf;
307 spin_unlock(&root->fs_info->hash_lock);
308 return 0;
309 }
310 spin_unlock(&root->fs_info->hash_lock);
311 search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
312 ret = __btrfs_cow_block(trans, root, buf, parent,
313 parent_slot, cow_ret, search_start, 0);
314 return ret;
315 }
316
317 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
318 {
319 if (blocknr < other && other - (blocknr + blocksize) < 32768)
320 return 1;
321 if (blocknr > other && blocknr - (other + blocksize) < 32768)
322 return 1;
323 return 0;
324 }
325
326 /*
327 * compare two keys in a memcmp fashion
328 */
329 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
330 {
331 struct btrfs_key k1;
332
333 btrfs_disk_key_to_cpu(&k1, disk);
334
335 if (k1.objectid > k2->objectid)
336 return 1;
337 if (k1.objectid < k2->objectid)
338 return -1;
339 if (k1.type > k2->type)
340 return 1;
341 if (k1.type < k2->type)
342 return -1;
343 if (k1.offset > k2->offset)
344 return 1;
345 if (k1.offset < k2->offset)
346 return -1;
347 return 0;
348 }
349
350
351 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
352 struct btrfs_root *root, struct extent_buffer *parent,
353 int start_slot, int cache_only, u64 *last_ret,
354 struct btrfs_key *progress)
355 {
356 struct extent_buffer *cur;
357 struct extent_buffer *tmp;
358 u64 blocknr;
359 u64 gen;
360 u64 search_start = *last_ret;
361 u64 last_block = 0;
362 u64 other;
363 u32 parent_nritems;
364 int end_slot;
365 int i;
366 int err = 0;
367 int parent_level;
368 int uptodate;
369 u32 blocksize;
370 int progress_passed = 0;
371 struct btrfs_disk_key disk_key;
372
373 /* FIXME this code needs locking */
374 return 0;
375
376 parent_level = btrfs_header_level(parent);
377 if (cache_only && parent_level != 1)
378 return 0;
379
380 if (trans->transaction != root->fs_info->running_transaction) {
381 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
382 root->fs_info->running_transaction->transid);
383 WARN_ON(1);
384 }
385 if (trans->transid != root->fs_info->generation) {
386 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
387 root->fs_info->generation);
388 WARN_ON(1);
389 }
390
391 parent_nritems = btrfs_header_nritems(parent);
392 blocksize = btrfs_level_size(root, parent_level - 1);
393 end_slot = parent_nritems;
394
395 if (parent_nritems == 1)
396 return 0;
397
398 for (i = start_slot; i < end_slot; i++) {
399 int close = 1;
400
401 if (!parent->map_token) {
402 map_extent_buffer(parent,
403 btrfs_node_key_ptr_offset(i),
404 sizeof(struct btrfs_key_ptr),
405 &parent->map_token, &parent->kaddr,
406 &parent->map_start, &parent->map_len,
407 KM_USER1);
408 }
409 btrfs_node_key(parent, &disk_key, i);
410 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
411 continue;
412
413 progress_passed = 1;
414 blocknr = btrfs_node_blockptr(parent, i);
415 gen = btrfs_node_ptr_generation(parent, i);
416 if (last_block == 0)
417 last_block = blocknr;
418
419 if (i > 0) {
420 other = btrfs_node_blockptr(parent, i - 1);
421 close = close_blocks(blocknr, other, blocksize);
422 }
423 if (!close && i < end_slot - 2) {
424 other = btrfs_node_blockptr(parent, i + 1);
425 close = close_blocks(blocknr, other, blocksize);
426 }
427 if (close) {
428 last_block = blocknr;
429 continue;
430 }
431 if (parent->map_token) {
432 unmap_extent_buffer(parent, parent->map_token,
433 KM_USER1);
434 parent->map_token = NULL;
435 }
436
437 cur = btrfs_find_tree_block(root, blocknr, blocksize);
438 if (cur)
439 uptodate = btrfs_buffer_uptodate(cur, gen);
440 else
441 uptodate = 0;
442 if (!cur || !uptodate) {
443 if (cache_only) {
444 free_extent_buffer(cur);
445 continue;
446 }
447 if (!cur) {
448 cur = read_tree_block(root, blocknr,
449 blocksize, gen);
450 } else if (!uptodate) {
451 btrfs_read_buffer(cur, gen);
452 }
453 }
454 if (search_start == 0)
455 search_start = last_block;
456
457 err = __btrfs_cow_block(trans, root, cur, parent, i,
458 &tmp, search_start,
459 min(16 * blocksize,
460 (end_slot - i) * blocksize));
461 if (err) {
462 free_extent_buffer(cur);
463 break;
464 }
465 search_start = tmp->start;
466 last_block = tmp->start;
467 *last_ret = search_start;
468 if (parent_level == 1)
469 btrfs_clear_buffer_defrag(tmp);
470 free_extent_buffer(tmp);
471 }
472 if (parent->map_token) {
473 unmap_extent_buffer(parent, parent->map_token,
474 KM_USER1);
475 parent->map_token = NULL;
476 }
477 return err;
478 }
479
480 /*
481 * The leaf data grows from end-to-front in the node.
482 * this returns the address of the start of the last item,
483 * which is the stop of the leaf data stack
484 */
485 static inline unsigned int leaf_data_end(struct btrfs_root *root,
486 struct extent_buffer *leaf)
487 {
488 u32 nr = btrfs_header_nritems(leaf);
489 if (nr == 0)
490 return BTRFS_LEAF_DATA_SIZE(root);
491 return btrfs_item_offset_nr(leaf, nr - 1);
492 }
493
494 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
495 int level)
496 {
497 struct extent_buffer *parent = NULL;
498 struct extent_buffer *node = path->nodes[level];
499 struct btrfs_disk_key parent_key;
500 struct btrfs_disk_key node_key;
501 int parent_slot;
502 int slot;
503 struct btrfs_key cpukey;
504 u32 nritems = btrfs_header_nritems(node);
505
506 if (path->nodes[level + 1])
507 parent = path->nodes[level + 1];
508
509 slot = path->slots[level];
510 BUG_ON(nritems == 0);
511 if (parent) {
512 parent_slot = path->slots[level + 1];
513 btrfs_node_key(parent, &parent_key, parent_slot);
514 btrfs_node_key(node, &node_key, 0);
515 BUG_ON(memcmp(&parent_key, &node_key,
516 sizeof(struct btrfs_disk_key)));
517 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
518 btrfs_header_bytenr(node));
519 }
520 BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
521 if (slot != 0) {
522 btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
523 btrfs_node_key(node, &node_key, slot);
524 BUG_ON(comp_keys(&node_key, &cpukey) <= 0);
525 }
526 if (slot < nritems - 1) {
527 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
528 btrfs_node_key(node, &node_key, slot);
529 BUG_ON(comp_keys(&node_key, &cpukey) >= 0);
530 }
531 return 0;
532 }
533
534 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
535 int level)
536 {
537 struct extent_buffer *leaf = path->nodes[level];
538 struct extent_buffer *parent = NULL;
539 int parent_slot;
540 struct btrfs_key cpukey;
541 struct btrfs_disk_key parent_key;
542 struct btrfs_disk_key leaf_key;
543 int slot = path->slots[0];
544
545 u32 nritems = btrfs_header_nritems(leaf);
546
547 if (path->nodes[level + 1])
548 parent = path->nodes[level + 1];
549
550 if (nritems == 0)
551 return 0;
552
553 if (parent) {
554 parent_slot = path->slots[level + 1];
555 btrfs_node_key(parent, &parent_key, parent_slot);
556 btrfs_item_key(leaf, &leaf_key, 0);
557
558 BUG_ON(memcmp(&parent_key, &leaf_key,
559 sizeof(struct btrfs_disk_key)));
560 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
561 btrfs_header_bytenr(leaf));
562 }
563 #if 0
564 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
565 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
566 btrfs_item_key(leaf, &leaf_key, i);
567 if (comp_keys(&leaf_key, &cpukey) >= 0) {
568 btrfs_print_leaf(root, leaf);
569 printk("slot %d offset bad key\n", i);
570 BUG_ON(1);
571 }
572 if (btrfs_item_offset_nr(leaf, i) !=
573 btrfs_item_end_nr(leaf, i + 1)) {
574 btrfs_print_leaf(root, leaf);
575 printk("slot %d offset bad\n", i);
576 BUG_ON(1);
577 }
578 if (i == 0) {
579 if (btrfs_item_offset_nr(leaf, i) +
580 btrfs_item_size_nr(leaf, i) !=
581 BTRFS_LEAF_DATA_SIZE(root)) {
582 btrfs_print_leaf(root, leaf);
583 printk("slot %d first offset bad\n", i);
584 BUG_ON(1);
585 }
586 }
587 }
588 if (nritems > 0) {
589 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
590 btrfs_print_leaf(root, leaf);
591 printk("slot %d bad size \n", nritems - 1);
592 BUG_ON(1);
593 }
594 }
595 #endif
596 if (slot != 0 && slot < nritems - 1) {
597 btrfs_item_key(leaf, &leaf_key, slot);
598 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
599 if (comp_keys(&leaf_key, &cpukey) <= 0) {
600 btrfs_print_leaf(root, leaf);
601 printk("slot %d offset bad key\n", slot);
602 BUG_ON(1);
603 }
604 if (btrfs_item_offset_nr(leaf, slot - 1) !=
605 btrfs_item_end_nr(leaf, slot)) {
606 btrfs_print_leaf(root, leaf);
607 printk("slot %d offset bad\n", slot);
608 BUG_ON(1);
609 }
610 }
611 if (slot < nritems - 1) {
612 btrfs_item_key(leaf, &leaf_key, slot);
613 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
614 BUG_ON(comp_keys(&leaf_key, &cpukey) >= 0);
615 if (btrfs_item_offset_nr(leaf, slot) !=
616 btrfs_item_end_nr(leaf, slot + 1)) {
617 btrfs_print_leaf(root, leaf);
618 printk("slot %d offset bad\n", slot);
619 BUG_ON(1);
620 }
621 }
622 BUG_ON(btrfs_item_offset_nr(leaf, 0) +
623 btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
624 return 0;
625 }
626
627 static int noinline check_block(struct btrfs_root *root,
628 struct btrfs_path *path, int level)
629 {
630 u64 found_start;
631 return 0;
632 if (btrfs_header_level(path->nodes[level]) != level)
633 printk("warning: bad level %Lu wanted %d found %d\n",
634 path->nodes[level]->start, level,
635 btrfs_header_level(path->nodes[level]));
636 found_start = btrfs_header_bytenr(path->nodes[level]);
637 if (found_start != path->nodes[level]->start) {
638 printk("warning: bad bytentr %Lu found %Lu\n",
639 path->nodes[level]->start, found_start);
640 }
641 #if 0
642 struct extent_buffer *buf = path->nodes[level];
643
644 if (memcmp_extent_buffer(buf, root->fs_info->fsid,
645 (unsigned long)btrfs_header_fsid(buf),
646 BTRFS_FSID_SIZE)) {
647 printk("warning bad block %Lu\n", buf->start);
648 return 1;
649 }
650 #endif
651 if (level == 0)
652 return check_leaf(root, path, level);
653 return check_node(root, path, level);
654 }
655
656 /*
657 * search for key in the extent_buffer. The items start at offset p,
658 * and they are item_size apart. There are 'max' items in p.
659 *
660 * the slot in the array is returned via slot, and it points to
661 * the place where you would insert key if it is not found in
662 * the array.
663 *
664 * slot may point to max if the key is bigger than all of the keys
665 */
666 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
667 int item_size, struct btrfs_key *key,
668 int max, int *slot)
669 {
670 int low = 0;
671 int high = max;
672 int mid;
673 int ret;
674 struct btrfs_disk_key *tmp = NULL;
675 struct btrfs_disk_key unaligned;
676 unsigned long offset;
677 char *map_token = NULL;
678 char *kaddr = NULL;
679 unsigned long map_start = 0;
680 unsigned long map_len = 0;
681 int err;
682
683 while(low < high) {
684 mid = (low + high) / 2;
685 offset = p + mid * item_size;
686
687 if (!map_token || offset < map_start ||
688 (offset + sizeof(struct btrfs_disk_key)) >
689 map_start + map_len) {
690 if (map_token) {
691 unmap_extent_buffer(eb, map_token, KM_USER0);
692 map_token = NULL;
693 }
694 err = map_extent_buffer(eb, offset,
695 sizeof(struct btrfs_disk_key),
696 &map_token, &kaddr,
697 &map_start, &map_len, KM_USER0);
698
699 if (!err) {
700 tmp = (struct btrfs_disk_key *)(kaddr + offset -
701 map_start);
702 } else {
703 read_extent_buffer(eb, &unaligned,
704 offset, sizeof(unaligned));
705 tmp = &unaligned;
706 }
707
708 } else {
709 tmp = (struct btrfs_disk_key *)(kaddr + offset -
710 map_start);
711 }
712 ret = comp_keys(tmp, key);
713
714 if (ret < 0)
715 low = mid + 1;
716 else if (ret > 0)
717 high = mid;
718 else {
719 *slot = mid;
720 if (map_token)
721 unmap_extent_buffer(eb, map_token, KM_USER0);
722 return 0;
723 }
724 }
725 *slot = low;
726 if (map_token)
727 unmap_extent_buffer(eb, map_token, KM_USER0);
728 return 1;
729 }
730
731 /*
732 * simple bin_search frontend that does the right thing for
733 * leaves vs nodes
734 */
735 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
736 int level, int *slot)
737 {
738 if (level == 0) {
739 return generic_bin_search(eb,
740 offsetof(struct btrfs_leaf, items),
741 sizeof(struct btrfs_item),
742 key, btrfs_header_nritems(eb),
743 slot);
744 } else {
745 return generic_bin_search(eb,
746 offsetof(struct btrfs_node, ptrs),
747 sizeof(struct btrfs_key_ptr),
748 key, btrfs_header_nritems(eb),
749 slot);
750 }
751 return -1;
752 }
753
754 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
755 struct extent_buffer *parent, int slot)
756 {
757 int level = btrfs_header_level(parent);
758 if (slot < 0)
759 return NULL;
760 if (slot >= btrfs_header_nritems(parent))
761 return NULL;
762
763 BUG_ON(level == 0);
764
765 return read_tree_block(root, btrfs_node_blockptr(parent, slot),
766 btrfs_level_size(root, level - 1),
767 btrfs_node_ptr_generation(parent, slot));
768 }
769
770 static int balance_level(struct btrfs_trans_handle *trans,
771 struct btrfs_root *root,
772 struct btrfs_path *path, int level)
773 {
774 struct extent_buffer *right = NULL;
775 struct extent_buffer *mid;
776 struct extent_buffer *left = NULL;
777 struct extent_buffer *parent = NULL;
778 int ret = 0;
779 int wret;
780 int pslot;
781 int orig_slot = path->slots[level];
782 int err_on_enospc = 0;
783 u64 orig_ptr;
784
785 if (level == 0)
786 return 0;
787
788 mid = path->nodes[level];
789 WARN_ON(!path->locks[level]);
790 WARN_ON(btrfs_header_generation(mid) != trans->transid);
791
792 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
793
794 if (level < BTRFS_MAX_LEVEL - 1)
795 parent = path->nodes[level + 1];
796 pslot = path->slots[level + 1];
797
798 /*
799 * deal with the case where there is only one pointer in the root
800 * by promoting the node below to a root
801 */
802 if (!parent) {
803 struct extent_buffer *child;
804
805 if (btrfs_header_nritems(mid) != 1)
806 return 0;
807
808 /* promote the child to a root */
809 child = read_node_slot(root, mid, 0);
810 btrfs_tree_lock(child);
811 BUG_ON(!child);
812 ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
813 BUG_ON(ret);
814
815 spin_lock(&root->node_lock);
816 root->node = child;
817 spin_unlock(&root->node_lock);
818
819 add_root_to_dirty_list(root);
820 btrfs_tree_unlock(child);
821 path->locks[level] = 0;
822 path->nodes[level] = NULL;
823 clean_tree_block(trans, root, mid);
824 btrfs_tree_unlock(mid);
825 /* once for the path */
826 free_extent_buffer(mid);
827 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
828 root->root_key.objectid,
829 btrfs_header_generation(mid), 0, 0, 1);
830 /* once for the root ptr */
831 free_extent_buffer(mid);
832 return ret;
833 }
834 if (btrfs_header_nritems(mid) >
835 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
836 return 0;
837
838 if (btrfs_header_nritems(mid) < 2)
839 err_on_enospc = 1;
840
841 left = read_node_slot(root, parent, pslot - 1);
842 if (left) {
843 btrfs_tree_lock(left);
844 wret = btrfs_cow_block(trans, root, left,
845 parent, pslot - 1, &left);
846 if (wret) {
847 ret = wret;
848 goto enospc;
849 }
850 }
851 right = read_node_slot(root, parent, pslot + 1);
852 if (right) {
853 btrfs_tree_lock(right);
854 wret = btrfs_cow_block(trans, root, right,
855 parent, pslot + 1, &right);
856 if (wret) {
857 ret = wret;
858 goto enospc;
859 }
860 }
861
862 /* first, try to make some room in the middle buffer */
863 if (left) {
864 orig_slot += btrfs_header_nritems(left);
865 wret = push_node_left(trans, root, left, mid, 1);
866 if (wret < 0)
867 ret = wret;
868 if (btrfs_header_nritems(mid) < 2)
869 err_on_enospc = 1;
870 }
871
872 /*
873 * then try to empty the right most buffer into the middle
874 */
875 if (right) {
876 wret = push_node_left(trans, root, mid, right, 1);
877 if (wret < 0 && wret != -ENOSPC)
878 ret = wret;
879 if (btrfs_header_nritems(right) == 0) {
880 u64 bytenr = right->start;
881 u64 generation = btrfs_header_generation(parent);
882 u32 blocksize = right->len;
883
884 clean_tree_block(trans, root, right);
885 btrfs_tree_unlock(right);
886 free_extent_buffer(right);
887 right = NULL;
888 wret = del_ptr(trans, root, path, level + 1, pslot +
889 1);
890 if (wret)
891 ret = wret;
892 wret = btrfs_free_extent(trans, root, bytenr,
893 blocksize,
894 btrfs_header_owner(parent),
895 generation, 0, 0, 1);
896 if (wret)
897 ret = wret;
898 } else {
899 struct btrfs_disk_key right_key;
900 btrfs_node_key(right, &right_key, 0);
901 btrfs_set_node_key(parent, &right_key, pslot + 1);
902 btrfs_mark_buffer_dirty(parent);
903 }
904 }
905 if (btrfs_header_nritems(mid) == 1) {
906 /*
907 * we're not allowed to leave a node with one item in the
908 * tree during a delete. A deletion from lower in the tree
909 * could try to delete the only pointer in this node.
910 * So, pull some keys from the left.
911 * There has to be a left pointer at this point because
912 * otherwise we would have pulled some pointers from the
913 * right
914 */
915 BUG_ON(!left);
916 wret = balance_node_right(trans, root, mid, left);
917 if (wret < 0) {
918 ret = wret;
919 goto enospc;
920 }
921 if (wret == 1) {
922 wret = push_node_left(trans, root, left, mid, 1);
923 if (wret < 0)
924 ret = wret;
925 }
926 BUG_ON(wret == 1);
927 }
928 if (btrfs_header_nritems(mid) == 0) {
929 /* we've managed to empty the middle node, drop it */
930 u64 root_gen = btrfs_header_generation(parent);
931 u64 bytenr = mid->start;
932 u32 blocksize = mid->len;
933
934 clean_tree_block(trans, root, mid);
935 btrfs_tree_unlock(mid);
936 free_extent_buffer(mid);
937 mid = NULL;
938 wret = del_ptr(trans, root, path, level + 1, pslot);
939 if (wret)
940 ret = wret;
941 wret = btrfs_free_extent(trans, root, bytenr, blocksize,
942 btrfs_header_owner(parent),
943 root_gen, 0, 0, 1);
944 if (wret)
945 ret = wret;
946 } else {
947 /* update the parent key to reflect our changes */
948 struct btrfs_disk_key mid_key;
949 btrfs_node_key(mid, &mid_key, 0);
950 btrfs_set_node_key(parent, &mid_key, pslot);
951 btrfs_mark_buffer_dirty(parent);
952 }
953
954 /* update the path */
955 if (left) {
956 if (btrfs_header_nritems(left) > orig_slot) {
957 extent_buffer_get(left);
958 /* left was locked after cow */
959 path->nodes[level] = left;
960 path->slots[level + 1] -= 1;
961 path->slots[level] = orig_slot;
962 if (mid) {
963 btrfs_tree_unlock(mid);
964 free_extent_buffer(mid);
965 }
966 } else {
967 orig_slot -= btrfs_header_nritems(left);
968 path->slots[level] = orig_slot;
969 }
970 }
971 /* double check we haven't messed things up */
972 check_block(root, path, level);
973 if (orig_ptr !=
974 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
975 BUG();
976 enospc:
977 if (right) {
978 btrfs_tree_unlock(right);
979 free_extent_buffer(right);
980 }
981 if (left) {
982 if (path->nodes[level] != left)
983 btrfs_tree_unlock(left);
984 free_extent_buffer(left);
985 }
986 return ret;
987 }
988
989 /* returns zero if the push worked, non-zero otherwise */
990 static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
991 struct btrfs_root *root,
992 struct btrfs_path *path, int level)
993 {
994 struct extent_buffer *right = NULL;
995 struct extent_buffer *mid;
996 struct extent_buffer *left = NULL;
997 struct extent_buffer *parent = NULL;
998 int ret = 0;
999 int wret;
1000 int pslot;
1001 int orig_slot = path->slots[level];
1002 u64 orig_ptr;
1003
1004 if (level == 0)
1005 return 1;
1006
1007 mid = path->nodes[level];
1008 WARN_ON(btrfs_header_generation(mid) != trans->transid);
1009 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
1010
1011 if (level < BTRFS_MAX_LEVEL - 1)
1012 parent = path->nodes[level + 1];
1013 pslot = path->slots[level + 1];
1014
1015 if (!parent)
1016 return 1;
1017
1018 left = read_node_slot(root, parent, pslot - 1);
1019
1020 /* first, try to make some room in the middle buffer */
1021 if (left) {
1022 u32 left_nr;
1023
1024 btrfs_tree_lock(left);
1025 left_nr = btrfs_header_nritems(left);
1026 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1027 wret = 1;
1028 } else {
1029 ret = btrfs_cow_block(trans, root, left, parent,
1030 pslot - 1, &left);
1031 if (ret)
1032 wret = 1;
1033 else {
1034 wret = push_node_left(trans, root,
1035 left, mid, 0);
1036 }
1037 }
1038 if (wret < 0)
1039 ret = wret;
1040 if (wret == 0) {
1041 struct btrfs_disk_key disk_key;
1042 orig_slot += left_nr;
1043 btrfs_node_key(mid, &disk_key, 0);
1044 btrfs_set_node_key(parent, &disk_key, pslot);
1045 btrfs_mark_buffer_dirty(parent);
1046 if (btrfs_header_nritems(left) > orig_slot) {
1047 path->nodes[level] = left;
1048 path->slots[level + 1] -= 1;
1049 path->slots[level] = orig_slot;
1050 btrfs_tree_unlock(mid);
1051 free_extent_buffer(mid);
1052 } else {
1053 orig_slot -=
1054 btrfs_header_nritems(left);
1055 path->slots[level] = orig_slot;
1056 btrfs_tree_unlock(left);
1057 free_extent_buffer(left);
1058 }
1059 return 0;
1060 }
1061 btrfs_tree_unlock(left);
1062 free_extent_buffer(left);
1063 }
1064 right = read_node_slot(root, parent, pslot + 1);
1065
1066 /*
1067 * then try to empty the right most buffer into the middle
1068 */
1069 if (right) {
1070 u32 right_nr;
1071 btrfs_tree_lock(right);
1072 right_nr = btrfs_header_nritems(right);
1073 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1074 wret = 1;
1075 } else {
1076 ret = btrfs_cow_block(trans, root, right,
1077 parent, pslot + 1,
1078 &right);
1079 if (ret)
1080 wret = 1;
1081 else {
1082 wret = balance_node_right(trans, root,
1083 right, mid);
1084 }
1085 }
1086 if (wret < 0)
1087 ret = wret;
1088 if (wret == 0) {
1089 struct btrfs_disk_key disk_key;
1090
1091 btrfs_node_key(right, &disk_key, 0);
1092 btrfs_set_node_key(parent, &disk_key, pslot + 1);
1093 btrfs_mark_buffer_dirty(parent);
1094
1095 if (btrfs_header_nritems(mid) <= orig_slot) {
1096 path->nodes[level] = right;
1097 path->slots[level + 1] += 1;
1098 path->slots[level] = orig_slot -
1099 btrfs_header_nritems(mid);
1100 btrfs_tree_unlock(mid);
1101 free_extent_buffer(mid);
1102 } else {
1103 btrfs_tree_unlock(right);
1104 free_extent_buffer(right);
1105 }
1106 return 0;
1107 }
1108 btrfs_tree_unlock(right);
1109 free_extent_buffer(right);
1110 }
1111 return 1;
1112 }
1113
1114 /*
1115 * readahead one full node of leaves
1116 */
1117 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
1118 int level, int slot, u64 objectid)
1119 {
1120 struct extent_buffer *node;
1121 struct btrfs_disk_key disk_key;
1122 u32 nritems;
1123 u64 search;
1124 u64 lowest_read;
1125 u64 highest_read;
1126 u64 nread = 0;
1127 int direction = path->reada;
1128 struct extent_buffer *eb;
1129 u32 nr;
1130 u32 blocksize;
1131 u32 nscan = 0;
1132
1133 if (level != 1)
1134 return;
1135
1136 if (!path->nodes[level])
1137 return;
1138
1139 node = path->nodes[level];
1140 WARN_ON(!path->skip_locking && !btrfs_tree_locked(node));
1141
1142 search = btrfs_node_blockptr(node, slot);
1143 blocksize = btrfs_level_size(root, level - 1);
1144 eb = btrfs_find_tree_block(root, search, blocksize);
1145 if (eb) {
1146 free_extent_buffer(eb);
1147 return;
1148 }
1149
1150 highest_read = search;
1151 lowest_read = search;
1152
1153 nritems = btrfs_header_nritems(node);
1154 nr = slot;
1155 while(1) {
1156 if (direction < 0) {
1157 if (nr == 0)
1158 break;
1159 nr--;
1160 } else if (direction > 0) {
1161 nr++;
1162 if (nr >= nritems)
1163 break;
1164 }
1165 if (path->reada < 0 && objectid) {
1166 btrfs_node_key(node, &disk_key, nr);
1167 if (btrfs_disk_key_objectid(&disk_key) != objectid)
1168 break;
1169 }
1170 search = btrfs_node_blockptr(node, nr);
1171 if ((search >= lowest_read && search <= highest_read) ||
1172 (search < lowest_read && lowest_read - search <= 32768) ||
1173 (search > highest_read && search - highest_read <= 32768)) {
1174 readahead_tree_block(root, search, blocksize,
1175 btrfs_node_ptr_generation(node, nr));
1176 nread += blocksize;
1177 }
1178 nscan++;
1179 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
1180 break;
1181 if(nread > (1024 * 1024) || nscan > 128)
1182 break;
1183
1184 if (search < lowest_read)
1185 lowest_read = search;
1186 if (search > highest_read)
1187 highest_read = search;
1188 }
1189 }
1190
1191 static void unlock_up(struct btrfs_path *path, int level, int lowest_unlock)
1192 {
1193 int i;
1194 int skip_level = level;
1195 struct extent_buffer *t;
1196
1197 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1198 if (!path->nodes[i])
1199 break;
1200 if (!path->locks[i])
1201 break;
1202 if (path->slots[i] == 0) {
1203 skip_level = i + 1;
1204 continue;
1205 }
1206 if (path->keep_locks) {
1207 u32 nritems;
1208 t = path->nodes[i];
1209 nritems = btrfs_header_nritems(t);
1210 if (nritems < 2 || path->slots[i] >= nritems - 2) {
1211 if (path->keep_locks) {
1212 //printk("path %p skip level now %d\n", path, skip_level);
1213 }
1214 skip_level = i + 1;
1215 continue;
1216 }
1217 }
1218 t = path->nodes[i];
1219 if (i >= lowest_unlock && i > skip_level && path->locks[i]) {
1220 if (path->keep_locks) {
1221 //printk("path %p unlocking level %d slot %d nritems %d skip_level %d\n", path, i, path->slots[i], btrfs_header_nritems(t), skip_level);
1222 }
1223 btrfs_tree_unlock(t);
1224 path->locks[i] = 0;
1225 }
1226 }
1227 }
1228
1229 /*
1230 * look for key in the tree. path is filled in with nodes along the way
1231 * if key is found, we return zero and you can find the item in the leaf
1232 * level of the path (level 0)
1233 *
1234 * If the key isn't found, the path points to the slot where it should
1235 * be inserted, and 1 is returned. If there are other errors during the
1236 * search a negative error number is returned.
1237 *
1238 * if ins_len > 0, nodes and leaves will be split as we walk down the
1239 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
1240 * possible)
1241 */
1242 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
1243 *root, struct btrfs_key *key, struct btrfs_path *p, int
1244 ins_len, int cow)
1245 {
1246 struct extent_buffer *b;
1247 int slot;
1248 int ret;
1249 int level;
1250 int should_reada = p->reada;
1251 int lowest_unlock = 1;
1252 u8 lowest_level = 0;
1253
1254 lowest_level = p->lowest_level;
1255 WARN_ON(lowest_level && ins_len);
1256 WARN_ON(p->nodes[0] != NULL);
1257 WARN_ON(root == root->fs_info->extent_root &&
1258 !mutex_is_locked(&root->fs_info->alloc_mutex));
1259 WARN_ON(root == root->fs_info->chunk_root &&
1260 !mutex_is_locked(&root->fs_info->chunk_mutex));
1261 WARN_ON(root == root->fs_info->dev_root &&
1262 !mutex_is_locked(&root->fs_info->chunk_mutex));
1263 if (ins_len < 0)
1264 lowest_unlock = 2;
1265 again:
1266 if (!p->skip_locking)
1267 b = btrfs_lock_root_node(root);
1268 else
1269 b = btrfs_root_node(root);
1270
1271 while (b) {
1272 level = btrfs_header_level(b);
1273 if (cow) {
1274 int wret;
1275 wret = btrfs_cow_block(trans, root, b,
1276 p->nodes[level + 1],
1277 p->slots[level + 1],
1278 &b);
1279 if (wret) {
1280 free_extent_buffer(b);
1281 return wret;
1282 }
1283 }
1284 BUG_ON(!cow && ins_len);
1285 if (level != btrfs_header_level(b))
1286 WARN_ON(1);
1287 level = btrfs_header_level(b);
1288 p->nodes[level] = b;
1289 if (!p->skip_locking)
1290 p->locks[level] = 1;
1291 ret = check_block(root, p, level);
1292 if (ret)
1293 return -1;
1294
1295 ret = bin_search(b, key, level, &slot);
1296 if (level != 0) {
1297 if (ret && slot > 0)
1298 slot -= 1;
1299 p->slots[level] = slot;
1300 if (ins_len > 0 && btrfs_header_nritems(b) >=
1301 BTRFS_NODEPTRS_PER_BLOCK(root) - 3) {
1302 int sret = split_node(trans, root, p, level);
1303 BUG_ON(sret > 0);
1304 if (sret)
1305 return sret;
1306 b = p->nodes[level];
1307 slot = p->slots[level];
1308 } else if (ins_len < 0) {
1309 int sret = balance_level(trans, root, p,
1310 level);
1311 if (sret)
1312 return sret;
1313 b = p->nodes[level];
1314 if (!b) {
1315 btrfs_release_path(NULL, p);
1316 goto again;
1317 }
1318 slot = p->slots[level];
1319 BUG_ON(btrfs_header_nritems(b) == 1);
1320 }
1321 /* this is only true while dropping a snapshot */
1322 if (level == lowest_level) {
1323 unlock_up(p, level, lowest_unlock);
1324 break;
1325 }
1326
1327 if (should_reada)
1328 reada_for_search(root, p, level, slot,
1329 key->objectid);
1330
1331 b = read_node_slot(root, b, slot);
1332 if (!p->skip_locking)
1333 btrfs_tree_lock(b);
1334 unlock_up(p, level + 1, lowest_unlock);
1335 } else {
1336 p->slots[level] = slot;
1337 if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1338 sizeof(struct btrfs_item) + ins_len) {
1339 int sret = split_leaf(trans, root, key,
1340 p, ins_len, ret == 0);
1341 BUG_ON(sret > 0);
1342 if (sret)
1343 return sret;
1344 }
1345 unlock_up(p, level, lowest_unlock);
1346 return ret;
1347 }
1348 }
1349 return 1;
1350 }
1351
1352 /*
1353 * adjust the pointers going up the tree, starting at level
1354 * making sure the right key of each node is points to 'key'.
1355 * This is used after shifting pointers to the left, so it stops
1356 * fixing up pointers when a given leaf/node is not in slot 0 of the
1357 * higher levels
1358 *
1359 * If this fails to write a tree block, it returns -1, but continues
1360 * fixing up the blocks in ram so the tree is consistent.
1361 */
1362 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1363 struct btrfs_root *root, struct btrfs_path *path,
1364 struct btrfs_disk_key *key, int level)
1365 {
1366 int i;
1367 int ret = 0;
1368 struct extent_buffer *t;
1369
1370 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1371 int tslot = path->slots[i];
1372 if (!path->nodes[i])
1373 break;
1374 t = path->nodes[i];
1375 btrfs_set_node_key(t, key, tslot);
1376 if (!btrfs_tree_locked(path->nodes[i])) {
1377 int ii;
1378 printk("fixup without lock on level %d\n", btrfs_header_level(path->nodes[i]));
1379 for (ii = 0; ii < BTRFS_MAX_LEVEL; ii++) {
1380 printk("level %d slot %d\n", ii, path->slots[ii]);
1381 }
1382 }
1383 btrfs_mark_buffer_dirty(path->nodes[i]);
1384 if (tslot != 0)
1385 break;
1386 }
1387 return ret;
1388 }
1389
1390 /*
1391 * try to push data from one node into the next node left in the
1392 * tree.
1393 *
1394 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1395 * error, and > 0 if there was no room in the left hand block.
1396 */
1397 static int push_node_left(struct btrfs_trans_handle *trans,
1398 struct btrfs_root *root, struct extent_buffer *dst,
1399 struct extent_buffer *src, int empty)
1400 {
1401 int push_items = 0;
1402 int src_nritems;
1403 int dst_nritems;
1404 int ret = 0;
1405
1406 src_nritems = btrfs_header_nritems(src);
1407 dst_nritems = btrfs_header_nritems(dst);
1408 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1409 WARN_ON(btrfs_header_generation(src) != trans->transid);
1410 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1411
1412 if (!empty && src_nritems <= 8)
1413 return 1;
1414
1415 if (push_items <= 0) {
1416 return 1;
1417 }
1418
1419 if (empty) {
1420 push_items = min(src_nritems, push_items);
1421 if (push_items < src_nritems) {
1422 /* leave at least 8 pointers in the node if
1423 * we aren't going to empty it
1424 */
1425 if (src_nritems - push_items < 8) {
1426 if (push_items <= 8)
1427 return 1;
1428 push_items -= 8;
1429 }
1430 }
1431 } else
1432 push_items = min(src_nritems - 8, push_items);
1433
1434 copy_extent_buffer(dst, src,
1435 btrfs_node_key_ptr_offset(dst_nritems),
1436 btrfs_node_key_ptr_offset(0),
1437 push_items * sizeof(struct btrfs_key_ptr));
1438
1439 if (push_items < src_nritems) {
1440 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1441 btrfs_node_key_ptr_offset(push_items),
1442 (src_nritems - push_items) *
1443 sizeof(struct btrfs_key_ptr));
1444 }
1445 btrfs_set_header_nritems(src, src_nritems - push_items);
1446 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1447 btrfs_mark_buffer_dirty(src);
1448 btrfs_mark_buffer_dirty(dst);
1449 return ret;
1450 }
1451
1452 /*
1453 * try to push data from one node into the next node right in the
1454 * tree.
1455 *
1456 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1457 * error, and > 0 if there was no room in the right hand block.
1458 *
1459 * this will only push up to 1/2 the contents of the left node over
1460 */
1461 static int balance_node_right(struct btrfs_trans_handle *trans,
1462 struct btrfs_root *root,
1463 struct extent_buffer *dst,
1464 struct extent_buffer *src)
1465 {
1466 int push_items = 0;
1467 int max_push;
1468 int src_nritems;
1469 int dst_nritems;
1470 int ret = 0;
1471
1472 WARN_ON(btrfs_header_generation(src) != trans->transid);
1473 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1474
1475 src_nritems = btrfs_header_nritems(src);
1476 dst_nritems = btrfs_header_nritems(dst);
1477 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1478 if (push_items <= 0) {
1479 return 1;
1480 }
1481
1482 if (src_nritems < 4) {
1483 return 1;
1484 }
1485
1486 max_push = src_nritems / 2 + 1;
1487 /* don't try to empty the node */
1488 if (max_push >= src_nritems) {
1489 return 1;
1490 }
1491
1492 if (max_push < push_items)
1493 push_items = max_push;
1494
1495 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1496 btrfs_node_key_ptr_offset(0),
1497 (dst_nritems) *
1498 sizeof(struct btrfs_key_ptr));
1499
1500 copy_extent_buffer(dst, src,
1501 btrfs_node_key_ptr_offset(0),
1502 btrfs_node_key_ptr_offset(src_nritems - push_items),
1503 push_items * sizeof(struct btrfs_key_ptr));
1504
1505 btrfs_set_header_nritems(src, src_nritems - push_items);
1506 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1507
1508 btrfs_mark_buffer_dirty(src);
1509 btrfs_mark_buffer_dirty(dst);
1510 return ret;
1511 }
1512
1513 /*
1514 * helper function to insert a new root level in the tree.
1515 * A new node is allocated, and a single item is inserted to
1516 * point to the existing root
1517 *
1518 * returns zero on success or < 0 on failure.
1519 */
1520 static int noinline insert_new_root(struct btrfs_trans_handle *trans,
1521 struct btrfs_root *root,
1522 struct btrfs_path *path, int level)
1523 {
1524 u64 root_gen;
1525 u64 lower_gen;
1526 struct extent_buffer *lower;
1527 struct extent_buffer *c;
1528 struct extent_buffer *old;
1529 struct btrfs_disk_key lower_key;
1530
1531 BUG_ON(path->nodes[level]);
1532 BUG_ON(path->nodes[level-1] != root->node);
1533
1534 if (root->ref_cows)
1535 root_gen = trans->transid;
1536 else
1537 root_gen = 0;
1538
1539 lower = path->nodes[level-1];
1540 if (level == 1)
1541 btrfs_item_key(lower, &lower_key, 0);
1542 else
1543 btrfs_node_key(lower, &lower_key, 0);
1544
1545 c = btrfs_alloc_free_block(trans, root, root->nodesize,
1546 root->root_key.objectid,
1547 root_gen, lower_key.objectid, level,
1548 root->node->start, 0);
1549 if (IS_ERR(c))
1550 return PTR_ERR(c);
1551
1552 memset_extent_buffer(c, 0, 0, root->nodesize);
1553 btrfs_set_header_nritems(c, 1);
1554 btrfs_set_header_level(c, level);
1555 btrfs_set_header_bytenr(c, c->start);
1556 btrfs_set_header_generation(c, trans->transid);
1557 btrfs_set_header_owner(c, root->root_key.objectid);
1558
1559 write_extent_buffer(c, root->fs_info->fsid,
1560 (unsigned long)btrfs_header_fsid(c),
1561 BTRFS_FSID_SIZE);
1562
1563 write_extent_buffer(c, root->fs_info->chunk_tree_uuid,
1564 (unsigned long)btrfs_header_chunk_tree_uuid(c),
1565 BTRFS_UUID_SIZE);
1566
1567 btrfs_set_node_key(c, &lower_key, 0);
1568 btrfs_set_node_blockptr(c, 0, lower->start);
1569 lower_gen = btrfs_header_generation(lower);
1570 WARN_ON(lower_gen == 0);
1571
1572 btrfs_set_node_ptr_generation(c, 0, lower_gen);
1573
1574 btrfs_mark_buffer_dirty(c);
1575
1576 spin_lock(&root->node_lock);
1577 old = root->node;
1578 root->node = c;
1579 spin_unlock(&root->node_lock);
1580
1581 /* the super has an extra ref to root->node */
1582 free_extent_buffer(old);
1583
1584 add_root_to_dirty_list(root);
1585 extent_buffer_get(c);
1586 path->nodes[level] = c;
1587 path->locks[level] = 1;
1588 path->slots[level] = 0;
1589
1590 if (root->ref_cows && lower_gen != trans->transid) {
1591 struct btrfs_path *back_path = btrfs_alloc_path();
1592 int ret;
1593 mutex_lock(&root->fs_info->alloc_mutex);
1594 ret = btrfs_insert_extent_backref(trans,
1595 root->fs_info->extent_root,
1596 path, lower->start,
1597 root->root_key.objectid,
1598 trans->transid, 0, 0);
1599 BUG_ON(ret);
1600 mutex_unlock(&root->fs_info->alloc_mutex);
1601 btrfs_free_path(back_path);
1602 }
1603 return 0;
1604 }
1605
1606 /*
1607 * worker function to insert a single pointer in a node.
1608 * the node should have enough room for the pointer already
1609 *
1610 * slot and level indicate where you want the key to go, and
1611 * blocknr is the block the key points to.
1612 *
1613 * returns zero on success and < 0 on any error
1614 */
1615 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1616 *root, struct btrfs_path *path, struct btrfs_disk_key
1617 *key, u64 bytenr, int slot, int level)
1618 {
1619 struct extent_buffer *lower;
1620 int nritems;
1621
1622 BUG_ON(!path->nodes[level]);
1623 lower = path->nodes[level];
1624 nritems = btrfs_header_nritems(lower);
1625 if (slot > nritems)
1626 BUG();
1627 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1628 BUG();
1629 if (slot != nritems) {
1630 memmove_extent_buffer(lower,
1631 btrfs_node_key_ptr_offset(slot + 1),
1632 btrfs_node_key_ptr_offset(slot),
1633 (nritems - slot) * sizeof(struct btrfs_key_ptr));
1634 }
1635 btrfs_set_node_key(lower, key, slot);
1636 btrfs_set_node_blockptr(lower, slot, bytenr);
1637 WARN_ON(trans->transid == 0);
1638 btrfs_set_node_ptr_generation(lower, slot, trans->transid);
1639 btrfs_set_header_nritems(lower, nritems + 1);
1640 btrfs_mark_buffer_dirty(lower);
1641 return 0;
1642 }
1643
1644 /*
1645 * split the node at the specified level in path in two.
1646 * The path is corrected to point to the appropriate node after the split
1647 *
1648 * Before splitting this tries to make some room in the node by pushing
1649 * left and right, if either one works, it returns right away.
1650 *
1651 * returns 0 on success and < 0 on failure
1652 */
1653 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1654 *root, struct btrfs_path *path, int level)
1655 {
1656 u64 root_gen;
1657 struct extent_buffer *c;
1658 struct extent_buffer *split;
1659 struct btrfs_disk_key disk_key;
1660 int mid;
1661 int ret;
1662 int wret;
1663 u32 c_nritems;
1664
1665 c = path->nodes[level];
1666 WARN_ON(btrfs_header_generation(c) != trans->transid);
1667 if (c == root->node) {
1668 /* trying to split the root, lets make a new one */
1669 ret = insert_new_root(trans, root, path, level + 1);
1670 if (ret)
1671 return ret;
1672 } else {
1673 ret = push_nodes_for_insert(trans, root, path, level);
1674 c = path->nodes[level];
1675 if (!ret && btrfs_header_nritems(c) <
1676 BTRFS_NODEPTRS_PER_BLOCK(root) - 3)
1677 return 0;
1678 if (ret < 0)
1679 return ret;
1680 }
1681
1682 c_nritems = btrfs_header_nritems(c);
1683 if (root->ref_cows)
1684 root_gen = trans->transid;
1685 else
1686 root_gen = 0;
1687
1688 btrfs_node_key(c, &disk_key, 0);
1689 split = btrfs_alloc_free_block(trans, root, root->nodesize,
1690 root->root_key.objectid,
1691 root_gen,
1692 btrfs_disk_key_objectid(&disk_key),
1693 level, c->start, 0);
1694 if (IS_ERR(split))
1695 return PTR_ERR(split);
1696
1697 btrfs_set_header_flags(split, btrfs_header_flags(c));
1698 btrfs_set_header_level(split, btrfs_header_level(c));
1699 btrfs_set_header_bytenr(split, split->start);
1700 btrfs_set_header_generation(split, trans->transid);
1701 btrfs_set_header_owner(split, root->root_key.objectid);
1702 btrfs_set_header_flags(split, 0);
1703 write_extent_buffer(split, root->fs_info->fsid,
1704 (unsigned long)btrfs_header_fsid(split),
1705 BTRFS_FSID_SIZE);
1706 write_extent_buffer(split, root->fs_info->chunk_tree_uuid,
1707 (unsigned long)btrfs_header_chunk_tree_uuid(split),
1708 BTRFS_UUID_SIZE);
1709
1710 mid = (c_nritems + 1) / 2;
1711
1712 copy_extent_buffer(split, c,
1713 btrfs_node_key_ptr_offset(0),
1714 btrfs_node_key_ptr_offset(mid),
1715 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1716 btrfs_set_header_nritems(split, c_nritems - mid);
1717 btrfs_set_header_nritems(c, mid);
1718 ret = 0;
1719
1720 btrfs_mark_buffer_dirty(c);
1721 btrfs_mark_buffer_dirty(split);
1722
1723 btrfs_node_key(split, &disk_key, 0);
1724 wret = insert_ptr(trans, root, path, &disk_key, split->start,
1725 path->slots[level + 1] + 1,
1726 level + 1);
1727 if (wret)
1728 ret = wret;
1729
1730 if (path->slots[level] >= mid) {
1731 path->slots[level] -= mid;
1732 btrfs_tree_unlock(c);
1733 free_extent_buffer(c);
1734 path->nodes[level] = split;
1735 path->slots[level + 1] += 1;
1736 } else {
1737 btrfs_tree_unlock(split);
1738 free_extent_buffer(split);
1739 }
1740 return ret;
1741 }
1742
1743 /*
1744 * how many bytes are required to store the items in a leaf. start
1745 * and nr indicate which items in the leaf to check. This totals up the
1746 * space used both by the item structs and the item data
1747 */
1748 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1749 {
1750 int data_len;
1751 int nritems = btrfs_header_nritems(l);
1752 int end = min(nritems, start + nr) - 1;
1753
1754 if (!nr)
1755 return 0;
1756 data_len = btrfs_item_end_nr(l, start);
1757 data_len = data_len - btrfs_item_offset_nr(l, end);
1758 data_len += sizeof(struct btrfs_item) * nr;
1759 WARN_ON(data_len < 0);
1760 return data_len;
1761 }
1762
1763 /*
1764 * The space between the end of the leaf items and
1765 * the start of the leaf data. IOW, how much room
1766 * the leaf has left for both items and data
1767 */
1768 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1769 {
1770 int nritems = btrfs_header_nritems(leaf);
1771 int ret;
1772 ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1773 if (ret < 0) {
1774 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1775 ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
1776 leaf_space_used(leaf, 0, nritems), nritems);
1777 }
1778 return ret;
1779 }
1780
1781 /*
1782 * push some data in the path leaf to the right, trying to free up at
1783 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1784 *
1785 * returns 1 if the push failed because the other node didn't have enough
1786 * room, 0 if everything worked out and < 0 if there were major errors.
1787 */
1788 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1789 *root, struct btrfs_path *path, int data_size,
1790 int empty)
1791 {
1792 struct extent_buffer *left = path->nodes[0];
1793 struct extent_buffer *right;
1794 struct extent_buffer *upper;
1795 struct btrfs_disk_key disk_key;
1796 int slot;
1797 u32 i;
1798 int free_space;
1799 int push_space = 0;
1800 int push_items = 0;
1801 struct btrfs_item *item;
1802 u32 left_nritems;
1803 u32 nr;
1804 u32 right_nritems;
1805 u32 data_end;
1806 u32 this_item_size;
1807 int ret;
1808
1809 slot = path->slots[1];
1810 if (!path->nodes[1]) {
1811 return 1;
1812 }
1813 upper = path->nodes[1];
1814 if (slot >= btrfs_header_nritems(upper) - 1)
1815 return 1;
1816
1817 WARN_ON(!btrfs_tree_locked(path->nodes[1]));
1818
1819 right = read_node_slot(root, upper, slot + 1);
1820 btrfs_tree_lock(right);
1821 free_space = btrfs_leaf_free_space(root, right);
1822 if (free_space < data_size + sizeof(struct btrfs_item))
1823 goto out_unlock;
1824
1825 /* cow and double check */
1826 ret = btrfs_cow_block(trans, root, right, upper,
1827 slot + 1, &right);
1828 if (ret)
1829 goto out_unlock;
1830
1831 free_space = btrfs_leaf_free_space(root, right);
1832 if (free_space < data_size + sizeof(struct btrfs_item))
1833 goto out_unlock;
1834
1835 left_nritems = btrfs_header_nritems(left);
1836 if (left_nritems == 0)
1837 goto out_unlock;
1838
1839 if (empty)
1840 nr = 0;
1841 else
1842 nr = 1;
1843
1844 i = left_nritems - 1;
1845 while (i >= nr) {
1846 item = btrfs_item_nr(left, i);
1847
1848 if (path->slots[0] == i)
1849 push_space += data_size + sizeof(*item);
1850
1851 if (!left->map_token) {
1852 map_extent_buffer(left, (unsigned long)item,
1853 sizeof(struct btrfs_item),
1854 &left->map_token, &left->kaddr,
1855 &left->map_start, &left->map_len,
1856 KM_USER1);
1857 }
1858
1859 this_item_size = btrfs_item_size(left, item);
1860 if (this_item_size + sizeof(*item) + push_space > free_space)
1861 break;
1862 push_items++;
1863 push_space += this_item_size + sizeof(*item);
1864 if (i == 0)
1865 break;
1866 i--;
1867 }
1868 if (left->map_token) {
1869 unmap_extent_buffer(left, left->map_token, KM_USER1);
1870 left->map_token = NULL;
1871 }
1872
1873 if (push_items == 0)
1874 goto out_unlock;
1875
1876 if (!empty && push_items == left_nritems)
1877 WARN_ON(1);
1878
1879 /* push left to right */
1880 right_nritems = btrfs_header_nritems(right);
1881
1882 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1883 push_space -= leaf_data_end(root, left);
1884
1885 /* make room in the right data area */
1886 data_end = leaf_data_end(root, right);
1887 memmove_extent_buffer(right,
1888 btrfs_leaf_data(right) + data_end - push_space,
1889 btrfs_leaf_data(right) + data_end,
1890 BTRFS_LEAF_DATA_SIZE(root) - data_end);
1891
1892 /* copy from the left data area */
1893 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1894 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1895 btrfs_leaf_data(left) + leaf_data_end(root, left),
1896 push_space);
1897
1898 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1899 btrfs_item_nr_offset(0),
1900 right_nritems * sizeof(struct btrfs_item));
1901
1902 /* copy the items from left to right */
1903 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1904 btrfs_item_nr_offset(left_nritems - push_items),
1905 push_items * sizeof(struct btrfs_item));
1906
1907 /* update the item pointers */
1908 right_nritems += push_items;
1909 btrfs_set_header_nritems(right, right_nritems);
1910 push_space = BTRFS_LEAF_DATA_SIZE(root);
1911 for (i = 0; i < right_nritems; i++) {
1912 item = btrfs_item_nr(right, i);
1913 if (!right->map_token) {
1914 map_extent_buffer(right, (unsigned long)item,
1915 sizeof(struct btrfs_item),
1916 &right->map_token, &right->kaddr,
1917 &right->map_start, &right->map_len,
1918 KM_USER1);
1919 }
1920 push_space -= btrfs_item_size(right, item);
1921 btrfs_set_item_offset(right, item, push_space);
1922 }
1923
1924 if (right->map_token) {
1925 unmap_extent_buffer(right, right->map_token, KM_USER1);
1926 right->map_token = NULL;
1927 }
1928 left_nritems -= push_items;
1929 btrfs_set_header_nritems(left, left_nritems);
1930
1931 if (left_nritems)
1932 btrfs_mark_buffer_dirty(left);
1933 btrfs_mark_buffer_dirty(right);
1934
1935 btrfs_item_key(right, &disk_key, 0);
1936 btrfs_set_node_key(upper, &disk_key, slot + 1);
1937 btrfs_mark_buffer_dirty(upper);
1938
1939 /* then fixup the leaf pointer in the path */
1940 if (path->slots[0] >= left_nritems) {
1941 path->slots[0] -= left_nritems;
1942 if (btrfs_header_nritems(path->nodes[0]) == 0)
1943 clean_tree_block(trans, root, path->nodes[0]);
1944 btrfs_tree_unlock(path->nodes[0]);
1945 free_extent_buffer(path->nodes[0]);
1946 path->nodes[0] = right;
1947 path->slots[1] += 1;
1948 } else {
1949 btrfs_tree_unlock(right);
1950 free_extent_buffer(right);
1951 }
1952 return 0;
1953
1954 out_unlock:
1955 btrfs_tree_unlock(right);
1956 free_extent_buffer(right);
1957 return 1;
1958 }
1959
1960 /*
1961 * push some data in the path leaf to the left, trying to free up at
1962 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1963 */
1964 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1965 *root, struct btrfs_path *path, int data_size,
1966 int empty)
1967 {
1968 struct btrfs_disk_key disk_key;
1969 struct extent_buffer *right = path->nodes[0];
1970 struct extent_buffer *left;
1971 int slot;
1972 int i;
1973 int free_space;
1974 int push_space = 0;
1975 int push_items = 0;
1976 struct btrfs_item *item;
1977 u32 old_left_nritems;
1978 u32 right_nritems;
1979 u32 nr;
1980 int ret = 0;
1981 int wret;
1982 u32 this_item_size;
1983 u32 old_left_item_size;
1984
1985 slot = path->slots[1];
1986 if (slot == 0)
1987 return 1;
1988 if (!path->nodes[1])
1989 return 1;
1990
1991 right_nritems = btrfs_header_nritems(right);
1992 if (right_nritems == 0) {
1993 return 1;
1994 }
1995
1996 WARN_ON(!btrfs_tree_locked(path->nodes[1]));
1997
1998 left = read_node_slot(root, path->nodes[1], slot - 1);
1999 btrfs_tree_lock(left);
2000 free_space = btrfs_leaf_free_space(root, left);
2001 if (free_space < data_size + sizeof(struct btrfs_item)) {
2002 ret = 1;
2003 goto out;
2004 }
2005
2006 /* cow and double check */
2007 ret = btrfs_cow_block(trans, root, left,
2008 path->nodes[1], slot - 1, &left);
2009 if (ret) {
2010 /* we hit -ENOSPC, but it isn't fatal here */
2011 ret = 1;
2012 goto out;
2013 }
2014
2015 free_space = btrfs_leaf_free_space(root, left);
2016 if (free_space < data_size + sizeof(struct btrfs_item)) {
2017 ret = 1;
2018 goto out;
2019 }
2020
2021 if (empty)
2022 nr = right_nritems;
2023 else
2024 nr = right_nritems - 1;
2025
2026 for (i = 0; i < nr; i++) {
2027 item = btrfs_item_nr(right, i);
2028 if (!right->map_token) {
2029 map_extent_buffer(right, (unsigned long)item,
2030 sizeof(struct btrfs_item),
2031 &right->map_token, &right->kaddr,
2032 &right->map_start, &right->map_len,
2033 KM_USER1);
2034 }
2035
2036 if (path->slots[0] == i)
2037 push_space += data_size + sizeof(*item);
2038
2039 this_item_size = btrfs_item_size(right, item);
2040 if (this_item_size + sizeof(*item) + push_space > free_space)
2041 break;
2042
2043 push_items++;
2044 push_space += this_item_size + sizeof(*item);
2045 }
2046
2047 if (right->map_token) {
2048 unmap_extent_buffer(right, right->map_token, KM_USER1);
2049 right->map_token = NULL;
2050 }
2051
2052 if (push_items == 0) {
2053 ret = 1;
2054 goto out;
2055 }
2056 if (!empty && push_items == btrfs_header_nritems(right))
2057 WARN_ON(1);
2058
2059 /* push data from right to left */
2060 copy_extent_buffer(left, right,
2061 btrfs_item_nr_offset(btrfs_header_nritems(left)),
2062 btrfs_item_nr_offset(0),
2063 push_items * sizeof(struct btrfs_item));
2064
2065 push_space = BTRFS_LEAF_DATA_SIZE(root) -
2066 btrfs_item_offset_nr(right, push_items -1);
2067
2068 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
2069 leaf_data_end(root, left) - push_space,
2070 btrfs_leaf_data(right) +
2071 btrfs_item_offset_nr(right, push_items - 1),
2072 push_space);
2073 old_left_nritems = btrfs_header_nritems(left);
2074 BUG_ON(old_left_nritems < 0);
2075
2076 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
2077 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
2078 u32 ioff;
2079
2080 item = btrfs_item_nr(left, i);
2081 if (!left->map_token) {
2082 map_extent_buffer(left, (unsigned long)item,
2083 sizeof(struct btrfs_item),
2084 &left->map_token, &left->kaddr,
2085 &left->map_start, &left->map_len,
2086 KM_USER1);
2087 }
2088
2089 ioff = btrfs_item_offset(left, item);
2090 btrfs_set_item_offset(left, item,
2091 ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
2092 }
2093 btrfs_set_header_nritems(left, old_left_nritems + push_items);
2094 if (left->map_token) {
2095 unmap_extent_buffer(left, left->map_token, KM_USER1);
2096 left->map_token = NULL;
2097 }
2098
2099 /* fixup right node */
2100 if (push_items > right_nritems) {
2101 printk("push items %d nr %u\n", push_items, right_nritems);
2102 WARN_ON(1);
2103 }
2104
2105 if (push_items < right_nritems) {
2106 push_space = btrfs_item_offset_nr(right, push_items - 1) -
2107 leaf_data_end(root, right);
2108 memmove_extent_buffer(right, btrfs_leaf_data(right) +
2109 BTRFS_LEAF_DATA_SIZE(root) - push_space,
2110 btrfs_leaf_data(right) +
2111 leaf_data_end(root, right), push_space);
2112
2113 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
2114 btrfs_item_nr_offset(push_items),
2115 (btrfs_header_nritems(right) - push_items) *
2116 sizeof(struct btrfs_item));
2117 }
2118 right_nritems -= push_items;
2119 btrfs_set_header_nritems(right, right_nritems);
2120 push_space = BTRFS_LEAF_DATA_SIZE(root);
2121 for (i = 0; i < right_nritems; i++) {
2122 item = btrfs_item_nr(right, i);
2123
2124 if (!right->map_token) {
2125 map_extent_buffer(right, (unsigned long)item,
2126 sizeof(struct btrfs_item),
2127 &right->map_token, &right->kaddr,
2128 &right->map_start, &right->map_len,
2129 KM_USER1);
2130 }
2131
2132 push_space = push_space - btrfs_item_size(right, item);
2133 btrfs_set_item_offset(right, item, push_space);
2134 }
2135 if (right->map_token) {
2136 unmap_extent_buffer(right, right->map_token, KM_USER1);
2137 right->map_token = NULL;
2138 }
2139
2140 btrfs_mark_buffer_dirty(left);
2141 if (right_nritems)
2142 btrfs_mark_buffer_dirty(right);
2143
2144 btrfs_item_key(right, &disk_key, 0);
2145 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
2146 if (wret)
2147 ret = wret;
2148
2149 /* then fixup the leaf pointer in the path */
2150 if (path->slots[0] < push_items) {
2151 path->slots[0] += old_left_nritems;
2152 if (btrfs_header_nritems(path->nodes[0]) == 0)
2153 clean_tree_block(trans, root, path->nodes[0]);
2154 btrfs_tree_unlock(path->nodes[0]);
2155 free_extent_buffer(path->nodes[0]);
2156 path->nodes[0] = left;
2157 path->slots[1] -= 1;
2158 } else {
2159 btrfs_tree_unlock(left);
2160 free_extent_buffer(left);
2161 path->slots[0] -= push_items;
2162 }
2163 BUG_ON(path->slots[0] < 0);
2164 return ret;
2165 out:
2166 btrfs_tree_unlock(left);
2167 free_extent_buffer(left);
2168 return ret;
2169 }
2170
2171 /*
2172 * split the path's leaf in two, making sure there is at least data_size
2173 * available for the resulting leaf level of the path.
2174 *
2175 * returns 0 if all went well and < 0 on failure.
2176 */
2177 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
2178 *root, struct btrfs_key *ins_key,
2179 struct btrfs_path *path, int data_size, int extend)
2180 {
2181 u64 root_gen;
2182 struct extent_buffer *l;
2183 u32 nritems;
2184 int mid;
2185 int slot;
2186 struct extent_buffer *right;
2187 int space_needed = data_size + sizeof(struct btrfs_item);
2188 int data_copy_size;
2189 int rt_data_off;
2190 int i;
2191 int ret = 0;
2192 int wret;
2193 int double_split;
2194 int num_doubles = 0;
2195 struct btrfs_disk_key disk_key;
2196
2197 if (extend)
2198 space_needed = data_size;
2199
2200 if (root->ref_cows)
2201 root_gen = trans->transid;
2202 else
2203 root_gen = 0;
2204
2205 /* first try to make some room by pushing left and right */
2206 if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
2207 wret = push_leaf_right(trans, root, path, data_size, 0);
2208 if (wret < 0) {
2209 return wret;
2210 }
2211 if (wret) {
2212 wret = push_leaf_left(trans, root, path, data_size, 0);
2213 if (wret < 0)
2214 return wret;
2215 }
2216 l = path->nodes[0];
2217
2218 /* did the pushes work? */
2219 if (btrfs_leaf_free_space(root, l) >= space_needed)
2220 return 0;
2221 }
2222
2223 if (!path->nodes[1]) {
2224 ret = insert_new_root(trans, root, path, 1);
2225 if (ret)
2226 return ret;
2227 }
2228 again:
2229 double_split = 0;
2230 l = path->nodes[0];
2231 slot = path->slots[0];
2232 nritems = btrfs_header_nritems(l);
2233 mid = (nritems + 1)/ 2;
2234
2235 btrfs_item_key(l, &disk_key, 0);
2236
2237 right = btrfs_alloc_free_block(trans, root, root->leafsize,
2238 root->root_key.objectid,
2239 root_gen, disk_key.objectid, 0,
2240 l->start, 0);
2241 if (IS_ERR(right)) {
2242 BUG_ON(1);
2243 return PTR_ERR(right);
2244 }
2245
2246 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
2247 btrfs_set_header_bytenr(right, right->start);
2248 btrfs_set_header_generation(right, trans->transid);
2249 btrfs_set_header_owner(right, root->root_key.objectid);
2250 btrfs_set_header_level(right, 0);
2251 write_extent_buffer(right, root->fs_info->fsid,
2252 (unsigned long)btrfs_header_fsid(right),
2253 BTRFS_FSID_SIZE);
2254
2255 write_extent_buffer(right, root->fs_info->chunk_tree_uuid,
2256 (unsigned long)btrfs_header_chunk_tree_uuid(right),
2257 BTRFS_UUID_SIZE);
2258 if (mid <= slot) {
2259 if (nritems == 1 ||
2260 leaf_space_used(l, mid, nritems - mid) + space_needed >
2261 BTRFS_LEAF_DATA_SIZE(root)) {
2262 if (slot >= nritems) {
2263 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2264 btrfs_set_header_nritems(right, 0);
2265 wret = insert_ptr(trans, root, path,
2266 &disk_key, right->start,
2267 path->slots[1] + 1, 1);
2268 if (wret)
2269 ret = wret;
2270
2271 btrfs_tree_unlock(path->nodes[0]);
2272 free_extent_buffer(path->nodes[0]);
2273 path->nodes[0] = right;
2274 path->slots[0] = 0;
2275 path->slots[1] += 1;
2276 btrfs_mark_buffer_dirty(right);
2277 return ret;
2278 }
2279 mid = slot;
2280 if (mid != nritems &&
2281 leaf_space_used(l, mid, nritems - mid) +
2282 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2283 double_split = 1;
2284 }
2285 }
2286 } else {
2287 if (leaf_space_used(l, 0, mid + 1) + space_needed >
2288 BTRFS_LEAF_DATA_SIZE(root)) {
2289 if (!extend && slot == 0) {
2290 btrfs_cpu_key_to_disk(&disk_key, ins_key);
2291 btrfs_set_header_nritems(right, 0);
2292 wret = insert_ptr(trans, root, path,
2293 &disk_key,
2294 right->start,
2295 path->slots[1], 1);
2296 if (wret)
2297 ret = wret;
2298 btrfs_tree_unlock(path->nodes[0]);
2299 free_extent_buffer(path->nodes[0]);
2300 path->nodes[0] = right;
2301 path->slots[0] = 0;
2302 if (path->slots[1] == 0) {
2303 wret = fixup_low_keys(trans, root,
2304 path, &disk_key, 1);
2305 if (wret)
2306 ret = wret;
2307 }
2308 btrfs_mark_buffer_dirty(right);
2309 return ret;
2310 } else if (extend && slot == 0) {
2311 mid = 1;
2312 } else {
2313 mid = slot;
2314 if (mid != nritems &&
2315 leaf_space_used(l, mid, nritems - mid) +
2316 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
2317 double_split = 1;
2318 }
2319 }
2320 }
2321 }
2322 nritems = nritems - mid;
2323 btrfs_set_header_nritems(right, nritems);
2324 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
2325
2326 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
2327 btrfs_item_nr_offset(mid),
2328 nritems * sizeof(struct btrfs_item));
2329
2330 copy_extent_buffer(right, l,
2331 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
2332 data_copy_size, btrfs_leaf_data(l) +
2333 leaf_data_end(root, l), data_copy_size);
2334
2335 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
2336 btrfs_item_end_nr(l, mid);
2337
2338 for (i = 0; i < nritems; i++) {
2339 struct btrfs_item *item = btrfs_item_nr(right, i);
2340 u32 ioff;
2341
2342 if (!right->map_token) {
2343 map_extent_buffer(right, (unsigned long)item,
2344 sizeof(struct btrfs_item),
2345 &right->map_token, &right->kaddr,
2346 &right->map_start, &right->map_len,
2347 KM_USER1);
2348 }
2349
2350 ioff = btrfs_item_offset(right, item);
2351 btrfs_set_item_offset(right, item, ioff + rt_data_off);
2352 }
2353
2354 if (right->map_token) {
2355 unmap_extent_buffer(right, right->map_token, KM_USER1);
2356 right->map_token = NULL;
2357 }
2358
2359 btrfs_set_header_nritems(l, mid);
2360 ret = 0;
2361 btrfs_item_key(right, &disk_key, 0);
2362 wret = insert_ptr(trans, root, path, &disk_key, right->start,
2363 path->slots[1] + 1, 1);
2364 if (wret)
2365 ret = wret;
2366
2367 btrfs_mark_buffer_dirty(right);
2368 btrfs_mark_buffer_dirty(l);
2369 BUG_ON(path->slots[0] != slot);
2370
2371 if (mid <= slot) {
2372 btrfs_tree_unlock(path->nodes[0]);
2373 free_extent_buffer(path->nodes[0]);
2374 path->nodes[0] = right;
2375 path->slots[0] -= mid;
2376 path->slots[1] += 1;
2377 } else {
2378 btrfs_tree_unlock(right);
2379 free_extent_buffer(right);
2380 }
2381
2382 BUG_ON(path->slots[0] < 0);
2383
2384 if (double_split) {
2385 BUG_ON(num_doubles != 0);
2386 num_doubles++;
2387 goto again;
2388 }
2389 return ret;
2390 }
2391
2392 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
2393 struct btrfs_root *root,
2394 struct btrfs_path *path,
2395 u32 new_size, int from_end)
2396 {
2397 int ret = 0;
2398 int slot;
2399 int slot_orig;
2400 struct extent_buffer *leaf;
2401 struct btrfs_item *item;
2402 u32 nritems;
2403 unsigned int data_end;
2404 unsigned int old_data_start;
2405 unsigned int old_size;
2406 unsigned int size_diff;
2407 int i;
2408
2409 slot_orig = path->slots[0];
2410 leaf = path->nodes[0];
2411 slot = path->slots[0];
2412
2413 old_size = btrfs_item_size_nr(leaf, slot);
2414 if (old_size == new_size)
2415 return 0;
2416
2417 nritems = btrfs_header_nritems(leaf);
2418 data_end = leaf_data_end(root, leaf);
2419
2420 old_data_start = btrfs_item_offset_nr(leaf, slot);
2421
2422 size_diff = old_size - new_size;
2423
2424 BUG_ON(slot < 0);
2425 BUG_ON(slot >= nritems);
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(leaf, i);
2434
2435 if (!leaf->map_token) {
2436 map_extent_buffer(leaf, (unsigned long)item,
2437 sizeof(struct btrfs_item),
2438 &leaf->map_token, &leaf->kaddr,
2439 &leaf->map_start, &leaf->map_len,
2440 KM_USER1);
2441 }
2442
2443 ioff = btrfs_item_offset(leaf, item);
2444 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2445 }
2446
2447 if (leaf->map_token) {
2448 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2449 leaf->map_token = NULL;
2450 }
2451
2452 /* shift the data */
2453 if (from_end) {
2454 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2455 data_end + size_diff, btrfs_leaf_data(leaf) +
2456 data_end, old_data_start + new_size - data_end);
2457 } else {
2458 struct btrfs_disk_key disk_key;
2459 u64 offset;
2460
2461 btrfs_item_key(leaf, &disk_key, slot);
2462
2463 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2464 unsigned long ptr;
2465 struct btrfs_file_extent_item *fi;
2466
2467 fi = btrfs_item_ptr(leaf, slot,
2468 struct btrfs_file_extent_item);
2469 fi = (struct btrfs_file_extent_item *)(
2470 (unsigned long)fi - size_diff);
2471
2472 if (btrfs_file_extent_type(leaf, fi) ==
2473 BTRFS_FILE_EXTENT_INLINE) {
2474 ptr = btrfs_item_ptr_offset(leaf, slot);
2475 memmove_extent_buffer(leaf, ptr,
2476 (unsigned long)fi,
2477 offsetof(struct btrfs_file_extent_item,
2478 disk_bytenr));
2479 }
2480 }
2481
2482 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2483 data_end + size_diff, btrfs_leaf_data(leaf) +
2484 data_end, old_data_start - data_end);
2485
2486 offset = btrfs_disk_key_offset(&disk_key);
2487 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2488 btrfs_set_item_key(leaf, &disk_key, slot);
2489 if (slot == 0)
2490 fixup_low_keys(trans, root, path, &disk_key, 1);
2491 }
2492
2493 item = btrfs_item_nr(leaf, slot);
2494 btrfs_set_item_size(leaf, item, new_size);
2495 btrfs_mark_buffer_dirty(leaf);
2496
2497 ret = 0;
2498 if (btrfs_leaf_free_space(root, leaf) < 0) {
2499 btrfs_print_leaf(root, leaf);
2500 BUG();
2501 }
2502 return ret;
2503 }
2504
2505 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2506 struct btrfs_root *root, struct btrfs_path *path,
2507 u32 data_size)
2508 {
2509 int ret = 0;
2510 int slot;
2511 int slot_orig;
2512 struct extent_buffer *leaf;
2513 struct btrfs_item *item;
2514 u32 nritems;
2515 unsigned int data_end;
2516 unsigned int old_data;
2517 unsigned int old_size;
2518 int i;
2519
2520 slot_orig = path->slots[0];
2521 leaf = path->nodes[0];
2522
2523 nritems = btrfs_header_nritems(leaf);
2524 data_end = leaf_data_end(root, leaf);
2525
2526 if (btrfs_leaf_free_space(root, leaf) < data_size) {
2527 btrfs_print_leaf(root, leaf);
2528 BUG();
2529 }
2530 slot = path->slots[0];
2531 old_data = btrfs_item_end_nr(leaf, slot);
2532
2533 BUG_ON(slot < 0);
2534 if (slot >= nritems) {
2535 btrfs_print_leaf(root, leaf);
2536 printk("slot %d too large, nritems %d\n", slot, nritems);
2537 BUG_ON(1);
2538 }
2539
2540 /*
2541 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2542 */
2543 /* first correct the data pointers */
2544 for (i = slot; i < nritems; i++) {
2545 u32 ioff;
2546 item = btrfs_item_nr(leaf, i);
2547
2548 if (!leaf->map_token) {
2549 map_extent_buffer(leaf, (unsigned long)item,
2550 sizeof(struct btrfs_item),
2551 &leaf->map_token, &leaf->kaddr,
2552 &leaf->map_start, &leaf->map_len,
2553 KM_USER1);
2554 }
2555 ioff = btrfs_item_offset(leaf, item);
2556 btrfs_set_item_offset(leaf, item, ioff - data_size);
2557 }
2558
2559 if (leaf->map_token) {
2560 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2561 leaf->map_token = NULL;
2562 }
2563
2564 /* shift the data */
2565 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2566 data_end - data_size, btrfs_leaf_data(leaf) +
2567 data_end, old_data - data_end);
2568
2569 data_end = old_data;
2570 old_size = btrfs_item_size_nr(leaf, slot);
2571 item = btrfs_item_nr(leaf, slot);
2572 btrfs_set_item_size(leaf, item, old_size + data_size);
2573 btrfs_mark_buffer_dirty(leaf);
2574
2575 ret = 0;
2576 if (btrfs_leaf_free_space(root, leaf) < 0) {
2577 btrfs_print_leaf(root, leaf);
2578 BUG();
2579 }
2580 return ret;
2581 }
2582
2583 /*
2584 * Given a key and some data, insert an item into the tree.
2585 * This does all the path init required, making room in the tree if needed.
2586 */
2587 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
2588 struct btrfs_root *root,
2589 struct btrfs_path *path,
2590 struct btrfs_key *cpu_key, u32 *data_size,
2591 int nr)
2592 {
2593 struct extent_buffer *leaf;
2594 struct btrfs_item *item;
2595 int ret = 0;
2596 int slot;
2597 int slot_orig;
2598 int i;
2599 u32 nritems;
2600 u32 total_size = 0;
2601 u32 total_data = 0;
2602 unsigned int data_end;
2603 struct btrfs_disk_key disk_key;
2604
2605 for (i = 0; i < nr; i++) {
2606 total_data += data_size[i];
2607 }
2608
2609 total_size = total_data + (nr - 1) * sizeof(struct btrfs_item);
2610 ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
2611 if (ret == 0) {
2612 return -EEXIST;
2613 }
2614 if (ret < 0)
2615 goto out;
2616
2617 slot_orig = path->slots[0];
2618 leaf = path->nodes[0];
2619
2620 nritems = btrfs_header_nritems(leaf);
2621 data_end = leaf_data_end(root, leaf);
2622
2623 if (btrfs_leaf_free_space(root, leaf) <
2624 sizeof(struct btrfs_item) + total_size) {
2625 btrfs_print_leaf(root, leaf);
2626 printk("not enough freespace need %u have %d\n",
2627 total_size, btrfs_leaf_free_space(root, leaf));
2628 BUG();
2629 }
2630
2631 slot = path->slots[0];
2632 BUG_ON(slot < 0);
2633
2634 if (slot != nritems) {
2635 int i;
2636 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2637
2638 if (old_data < data_end) {
2639 btrfs_print_leaf(root, leaf);
2640 printk("slot %d old_data %d data_end %d\n",
2641 slot, old_data, data_end);
2642 BUG_ON(1);
2643 }
2644 /*
2645 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2646 */
2647 /* first correct the data pointers */
2648 WARN_ON(leaf->map_token);
2649 for (i = slot; i < nritems; i++) {
2650 u32 ioff;
2651
2652 item = btrfs_item_nr(leaf, i);
2653 if (!leaf->map_token) {
2654 map_extent_buffer(leaf, (unsigned long)item,
2655 sizeof(struct btrfs_item),
2656 &leaf->map_token, &leaf->kaddr,
2657 &leaf->map_start, &leaf->map_len,
2658 KM_USER1);
2659 }
2660
2661 ioff = btrfs_item_offset(leaf, item);
2662 btrfs_set_item_offset(leaf, item, ioff - total_data);
2663 }
2664 if (leaf->map_token) {
2665 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2666 leaf->map_token = NULL;
2667 }
2668
2669 /* shift the items */
2670 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
2671 btrfs_item_nr_offset(slot),
2672 (nritems - slot) * sizeof(struct btrfs_item));
2673
2674 /* shift the data */
2675 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2676 data_end - total_data, btrfs_leaf_data(leaf) +
2677 data_end, old_data - data_end);
2678 data_end = old_data;
2679 }
2680
2681 /* setup the item for the new data */
2682 for (i = 0; i < nr; i++) {
2683 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
2684 btrfs_set_item_key(leaf, &disk_key, slot + i);
2685 item = btrfs_item_nr(leaf, slot + i);
2686 btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
2687 data_end -= data_size[i];
2688 btrfs_set_item_size(leaf, item, data_size[i]);
2689 }
2690 btrfs_set_header_nritems(leaf, nritems + nr);
2691 btrfs_mark_buffer_dirty(leaf);
2692
2693 ret = 0;
2694 if (slot == 0) {
2695 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2696 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2697 }
2698
2699 if (btrfs_leaf_free_space(root, leaf) < 0) {
2700 btrfs_print_leaf(root, leaf);
2701 BUG();
2702 }
2703 out:
2704 return ret;
2705 }
2706
2707 /*
2708 * Given a key and some data, insert an item into the tree.
2709 * This does all the path init required, making room in the tree if needed.
2710 */
2711 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2712 *root, struct btrfs_key *cpu_key, void *data, u32
2713 data_size)
2714 {
2715 int ret = 0;
2716 struct btrfs_path *path;
2717 struct extent_buffer *leaf;
2718 unsigned long ptr;
2719
2720 path = btrfs_alloc_path();
2721 BUG_ON(!path);
2722 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2723 if (!ret) {
2724 leaf = path->nodes[0];
2725 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2726 write_extent_buffer(leaf, data, ptr, data_size);
2727 btrfs_mark_buffer_dirty(leaf);
2728 }
2729 btrfs_free_path(path);
2730 return ret;
2731 }
2732
2733 /*
2734 * delete the pointer from a given node.
2735 *
2736 * If the delete empties a node, the node is removed from the tree,
2737 * continuing all the way the root if required. The root is converted into
2738 * a leaf if all the nodes are emptied.
2739 */
2740 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2741 struct btrfs_path *path, int level, int slot)
2742 {
2743 struct extent_buffer *parent = path->nodes[level];
2744 u32 nritems;
2745 int ret = 0;
2746 int wret;
2747
2748 nritems = btrfs_header_nritems(parent);
2749 if (slot != nritems -1) {
2750 memmove_extent_buffer(parent,
2751 btrfs_node_key_ptr_offset(slot),
2752 btrfs_node_key_ptr_offset(slot + 1),
2753 sizeof(struct btrfs_key_ptr) *
2754 (nritems - slot - 1));
2755 }
2756 nritems--;
2757 btrfs_set_header_nritems(parent, nritems);
2758 if (nritems == 0 && parent == root->node) {
2759 BUG_ON(btrfs_header_level(root->node) != 1);
2760 /* just turn the root into a leaf and break */
2761 btrfs_set_header_level(root->node, 0);
2762 } else if (slot == 0) {
2763 struct btrfs_disk_key disk_key;
2764
2765 btrfs_node_key(parent, &disk_key, 0);
2766 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2767 if (wret)
2768 ret = wret;
2769 }
2770 btrfs_mark_buffer_dirty(parent);
2771 return ret;
2772 }
2773
2774 /*
2775 * delete the item at the leaf level in path. If that empties
2776 * the leaf, remove it from the tree
2777 */
2778 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2779 struct btrfs_path *path, int slot, int nr)
2780 {
2781 struct extent_buffer *leaf;
2782 struct btrfs_item *item;
2783 int last_off;
2784 int dsize = 0;
2785 int ret = 0;
2786 int wret;
2787 int i;
2788 u32 nritems;
2789
2790 leaf = path->nodes[0];
2791 last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
2792
2793 for (i = 0; i < nr; i++)
2794 dsize += btrfs_item_size_nr(leaf, slot + i);
2795
2796 nritems = btrfs_header_nritems(leaf);
2797
2798 if (slot + nr != nritems) {
2799 int i;
2800 int data_end = leaf_data_end(root, leaf);
2801
2802 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2803 data_end + dsize,
2804 btrfs_leaf_data(leaf) + data_end,
2805 last_off - data_end);
2806
2807 for (i = slot + nr; i < nritems; i++) {
2808 u32 ioff;
2809
2810 item = btrfs_item_nr(leaf, i);
2811 if (!leaf->map_token) {
2812 map_extent_buffer(leaf, (unsigned long)item,
2813 sizeof(struct btrfs_item),
2814 &leaf->map_token, &leaf->kaddr,
2815 &leaf->map_start, &leaf->map_len,
2816 KM_USER1);
2817 }
2818 ioff = btrfs_item_offset(leaf, item);
2819 btrfs_set_item_offset(leaf, item, ioff + dsize);
2820 }
2821
2822 if (leaf->map_token) {
2823 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2824 leaf->map_token = NULL;
2825 }
2826
2827 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2828 btrfs_item_nr_offset(slot + nr),
2829 sizeof(struct btrfs_item) *
2830 (nritems - slot - nr));
2831 }
2832 btrfs_set_header_nritems(leaf, nritems - nr);
2833 nritems -= nr;
2834
2835 /* delete the leaf if we've emptied it */
2836 if (nritems == 0) {
2837 if (leaf == root->node) {
2838 btrfs_set_header_level(leaf, 0);
2839 } else {
2840 u64 root_gen = btrfs_header_generation(path->nodes[1]);
2841 wret = del_ptr(trans, root, path, 1, path->slots[1]);
2842 if (wret)
2843 ret = wret;
2844 wret = btrfs_free_extent(trans, root,
2845 leaf->start, leaf->len,
2846 btrfs_header_owner(path->nodes[1]),
2847 root_gen, 0, 0, 1);
2848 if (wret)
2849 ret = wret;
2850 }
2851 } else {
2852 int used = leaf_space_used(leaf, 0, nritems);
2853 if (slot == 0) {
2854 struct btrfs_disk_key disk_key;
2855
2856 btrfs_item_key(leaf, &disk_key, 0);
2857 wret = fixup_low_keys(trans, root, path,
2858 &disk_key, 1);
2859 if (wret)
2860 ret = wret;
2861 }
2862
2863 /* delete the leaf if it is mostly empty */
2864 if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
2865 /* push_leaf_left fixes the path.
2866 * make sure the path still points to our leaf
2867 * for possible call to del_ptr below
2868 */
2869 slot = path->slots[1];
2870 extent_buffer_get(leaf);
2871
2872 wret = push_leaf_left(trans, root, path, 1, 1);
2873 if (wret < 0 && wret != -ENOSPC)
2874 ret = wret;
2875
2876 if (path->nodes[0] == leaf &&
2877 btrfs_header_nritems(leaf)) {
2878 wret = push_leaf_right(trans, root, path, 1, 1);
2879 if (wret < 0 && wret != -ENOSPC)
2880 ret = wret;
2881 }
2882
2883 if (btrfs_header_nritems(leaf) == 0) {
2884 u64 root_gen;
2885 u64 bytenr = leaf->start;
2886 u32 blocksize = leaf->len;
2887
2888 root_gen = btrfs_header_generation(
2889 path->nodes[1]);
2890
2891 wret = del_ptr(trans, root, path, 1, slot);
2892 if (wret)
2893 ret = wret;
2894
2895 free_extent_buffer(leaf);
2896 wret = btrfs_free_extent(trans, root, bytenr,
2897 blocksize,
2898 btrfs_header_owner(path->nodes[1]),
2899 root_gen, 0, 0, 1);
2900 if (wret)
2901 ret = wret;
2902 } else {
2903 /* if we're still in the path, make sure
2904 * we're dirty. Otherwise, one of the
2905 * push_leaf functions must have already
2906 * dirtied this buffer
2907 */
2908 if (path->nodes[0] == leaf)
2909 btrfs_mark_buffer_dirty(leaf);
2910 free_extent_buffer(leaf);
2911 }
2912 } else {
2913 btrfs_mark_buffer_dirty(leaf);
2914 }
2915 }
2916 return ret;
2917 }
2918
2919 /*
2920 * search the tree again to find a leaf with lesser keys
2921 * returns 0 if it found something or 1 if there are no lesser leaves.
2922 * returns < 0 on io errors.
2923 */
2924 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
2925 {
2926 struct btrfs_key key;
2927 struct btrfs_disk_key found_key;
2928 int ret;
2929
2930 btrfs_item_key_to_cpu(path->nodes[0], &key, 0);
2931
2932 if (key.offset > 0)
2933 key.offset--;
2934 else if (key.type > 0)
2935 key.type--;
2936 else if (key.objectid > 0)
2937 key.objectid--;
2938 else
2939 return 1;
2940
2941 btrfs_release_path(root, path);
2942 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2943 if (ret < 0)
2944 return ret;
2945 btrfs_item_key(path->nodes[0], &found_key, 0);
2946 ret = comp_keys(&found_key, &key);
2947 if (ret < 0)
2948 return 0;
2949 return 1;
2950 }
2951
2952 /*
2953 * search the tree again to find a leaf with greater keys
2954 * returns 0 if it found something or 1 if there are no greater leaves.
2955 * returns < 0 on io errors.
2956 */
2957 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2958 {
2959 int slot;
2960 int level = 1;
2961 struct extent_buffer *c;
2962 struct extent_buffer *next = NULL;
2963 struct btrfs_key key;
2964 u32 nritems;
2965 int ret;
2966
2967 nritems = btrfs_header_nritems(path->nodes[0]);
2968 if (nritems == 0) {
2969 return 1;
2970 }
2971
2972 btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1);
2973
2974 btrfs_release_path(root, path);
2975 path->keep_locks = 1;
2976 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2977 path->keep_locks = 0;
2978
2979 if (ret < 0)
2980 return ret;
2981
2982 nritems = btrfs_header_nritems(path->nodes[0]);
2983 if (nritems > 0 && path->slots[0] < nritems - 1) {
2984 goto done;
2985 }
2986
2987 while(level < BTRFS_MAX_LEVEL) {
2988 if (!path->nodes[level])
2989 return 1;
2990
2991 slot = path->slots[level] + 1;
2992 c = path->nodes[level];
2993 if (slot >= btrfs_header_nritems(c)) {
2994 level++;
2995 if (level == BTRFS_MAX_LEVEL) {
2996 return 1;
2997 }
2998 continue;
2999 }
3000
3001 if (next) {
3002 btrfs_tree_unlock(next);
3003 free_extent_buffer(next);
3004 }
3005
3006 if (level == 1 && path->locks[1] && path->reada)
3007 reada_for_search(root, path, level, slot, 0);
3008
3009 next = read_node_slot(root, c, slot);
3010 if (!path->skip_locking) {
3011 if (!btrfs_tree_locked(c)) {
3012 int i;
3013 WARN_ON(1);
3014 printk("path %p no lock on level %d\n", path, level);
3015 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
3016 printk("path %p level %d slot %d nritems %d\n", path, i, path->slots[i], btrfs_header_nritems(path->nodes[i]));
3017 }
3018 }
3019 btrfs_tree_lock(next);
3020 }
3021 break;
3022 }
3023 path->slots[level] = slot;
3024 while(1) {
3025 level--;
3026 c = path->nodes[level];
3027 if (path->locks[level])
3028 btrfs_tree_unlock(c);
3029 free_extent_buffer(c);
3030 path->nodes[level] = next;
3031 path->slots[level] = 0;
3032 path->locks[level] = 1;
3033 if (!level)
3034 break;
3035 if (level == 1 && path->locks[1] && path->reada)
3036 reada_for_search(root, path, level, slot, 0);
3037 next = read_node_slot(root, next, 0);
3038 if (!path->skip_locking) {
3039 WARN_ON(!btrfs_tree_locked(path->nodes[level]));
3040 btrfs_tree_lock(next);
3041 }
3042 }
3043 done:
3044 unlock_up(path, 0, 1);
3045 return 0;
3046 }
3047
3048 int btrfs_previous_item(struct btrfs_root *root,
3049 struct btrfs_path *path, u64 min_objectid,
3050 int type)
3051 {
3052 struct btrfs_key found_key;
3053 struct extent_buffer *leaf;
3054 int ret;
3055
3056 while(1) {
3057 if (path->slots[0] == 0) {
3058 ret = btrfs_prev_leaf(root, path);
3059 if (ret != 0)
3060 return ret;
3061 } else {
3062 path->slots[0]--;
3063 }
3064 leaf = path->nodes[0];
3065 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3066 if (found_key.type == type)
3067 return 0;
3068 }
3069 return 1;
3070 }
3071
Linux kernel - Deliverables
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