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Update struct btrfs_header flags, and use it to indicate buffers are written
[btrfs-progs-unstable.git] / ctree.c
blobd172875ae683d7bd55c99b9ec358518e2c106fd5
1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18 #include "ctree.h"
19 #include "disk-io.h"
20 #include "transaction.h"
21 #include "print-tree.h"
22
23 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
24 *root, struct btrfs_path *path, int level);
25 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
26 *root, struct btrfs_key *ins_key,
27 struct btrfs_path *path, int data_size, int extend);
28 static int push_node_left(struct btrfs_trans_handle *trans,
29 struct btrfs_root *root, struct extent_buffer *dst,
30 struct extent_buffer *src);
31 static int balance_node_right(struct btrfs_trans_handle *trans,
32 struct btrfs_root *root,
33 struct extent_buffer *dst_buf,
34 struct extent_buffer *src_buf);
35 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
36 struct btrfs_path *path, int level, int slot);
37
38 inline void btrfs_init_path(struct btrfs_path *p)
39 {
40 memset(p, 0, sizeof(*p));
41 }
42
43 struct btrfs_path *btrfs_alloc_path(void)
44 {
45 struct btrfs_path *path;
46 path = kmalloc(sizeof(struct btrfs_path), GFP_NOFS);
47 if (path) {
48 btrfs_init_path(path);
49 path->reada = 0;
50 }
51 return path;
52 }
53
54 void btrfs_free_path(struct btrfs_path *p)
55 {
56 btrfs_release_path(NULL, p);
57 kfree(p);
58 }
59
60 void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
61 {
62 int i;
63 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
64 if (!p->nodes[i])
65 break;
66 free_extent_buffer(p->nodes[i]);
67 }
68 memset(p, 0, sizeof(*p));
69 }
70
71 static void add_root_to_dirty_list(struct btrfs_root *root)
72 {
73 if (root->track_dirty && list_empty(&root->dirty_list)) {
74 list_add(&root->dirty_list,
75 &root->fs_info->dirty_cowonly_roots);
76 }
77 }
78
79 int btrfs_copy_root(struct btrfs_trans_handle *trans,
80 struct btrfs_root *root,
81 struct extent_buffer *buf,
82 struct extent_buffer **cow_ret, u64 new_root_objectid)
83 {
84 struct extent_buffer *cow;
85 u32 nritems;
86 int ret = 0;
87 int level;
88 struct btrfs_key first_key;
89 struct btrfs_root *new_root;
90
91 new_root = kmalloc(sizeof(*new_root), GFP_NOFS);
92 if (!new_root)
93 return -ENOMEM;
94
95 memcpy(new_root, root, sizeof(*new_root));
96 new_root->root_key.objectid = new_root_objectid;
97
98 WARN_ON(root->ref_cows && trans->transid !=
99 root->fs_info->running_transaction->transid);
100 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
101
102 level = btrfs_header_level(buf);
103 nritems = btrfs_header_nritems(buf);
104 if (nritems) {
105 if (level == 0)
106 btrfs_item_key_to_cpu(buf, &first_key, 0);
107 else
108 btrfs_node_key_to_cpu(buf, &first_key, 0);
109 } else {
110 first_key.objectid = 0;
111 }
112 cow = __btrfs_alloc_free_block(trans, new_root, buf->len,
113 new_root_objectid,
114 trans->transid, first_key.objectid,
115 level, buf->start, 0);
116 if (IS_ERR(cow)) {
117 kfree(new_root);
118 return PTR_ERR(cow);
119 }
120
121 copy_extent_buffer(cow, buf, 0, 0, cow->len);
122 btrfs_set_header_bytenr(cow, cow->start);
123 btrfs_set_header_generation(cow, trans->transid);
124 btrfs_set_header_owner(cow, new_root_objectid);
125 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
126
127 WARN_ON(btrfs_header_generation(buf) > trans->transid);
128 ret = btrfs_inc_ref(trans, new_root, buf);
129 kfree(new_root);
130
131 if (ret)
132 return ret;
133
134 btrfs_mark_buffer_dirty(cow);
135 *cow_ret = cow;
136 return 0;
137 }
138
139 int __btrfs_cow_block(struct btrfs_trans_handle *trans,
140 struct btrfs_root *root,
141 struct extent_buffer *buf,
142 struct extent_buffer *parent, int parent_slot,
143 struct extent_buffer **cow_ret,
144 u64 search_start, u64 empty_size)
145 {
146 u64 root_gen;
147 struct extent_buffer *cow;
148 u32 nritems;
149 int ret = 0;
150 int different_trans = 0;
151 int level;
152 struct btrfs_key first_key;
153
154 if (root->ref_cows) {
155 root_gen = trans->transid;
156 } else {
157 root_gen = 0;
158 }
159
160 WARN_ON(root->ref_cows && trans->transid !=
161 root->fs_info->running_transaction->transid);
162 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
163
164 level = btrfs_header_level(buf);
165 nritems = btrfs_header_nritems(buf);
166 if (nritems) {
167 if (level == 0)
168 btrfs_item_key_to_cpu(buf, &first_key, 0);
169 else
170 btrfs_node_key_to_cpu(buf, &first_key, 0);
171 } else {
172 first_key.objectid = 0;
173 }
174 cow = __btrfs_alloc_free_block(trans, root, buf->len,
175 root->root_key.objectid,
176 root_gen, first_key.objectid, level,
177 search_start, empty_size);
178 if (IS_ERR(cow))
179 return PTR_ERR(cow);
180
181 copy_extent_buffer(cow, buf, 0, 0, cow->len);
182 btrfs_set_header_bytenr(cow, cow->start);
183 btrfs_set_header_generation(cow, trans->transid);
184 btrfs_set_header_owner(cow, root->root_key.objectid);
185 btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN);
186
187 WARN_ON(btrfs_header_generation(buf) > trans->transid);
188 if (btrfs_header_generation(buf) != trans->transid) {
189 different_trans = 1;
190 ret = btrfs_inc_ref(trans, root, buf);
191 if (ret)
192 return ret;
193 } else {
194 clean_tree_block(trans, root, buf);
195 }
196
197 if (buf == root->node) {
198 root_gen = btrfs_header_generation(buf);
199 root->node = cow;
200 extent_buffer_get(cow);
201 if (buf != root->commit_root) {
202 btrfs_free_extent(trans, root, buf->start,
203 buf->len, root->root_key.objectid,
204 root_gen, 0, 0, 1);
205 }
206 free_extent_buffer(buf);
207 add_root_to_dirty_list(root);
208 } else {
209 root_gen = btrfs_header_generation(parent);
210 btrfs_set_node_blockptr(parent, parent_slot,
211 cow->start);
212 WARN_ON(trans->transid == 0);
213 btrfs_set_node_ptr_generation(parent, parent_slot,
214 trans->transid);
215 btrfs_mark_buffer_dirty(parent);
216 WARN_ON(btrfs_header_generation(parent) != trans->transid);
217 btrfs_free_extent(trans, root, buf->start, buf->len,
218 btrfs_header_owner(parent), root_gen,
219 0, 0, 1);
220 }
221 free_extent_buffer(buf);
222 btrfs_mark_buffer_dirty(cow);
223 *cow_ret = cow;
224 return 0;
225 }
226
227 int btrfs_cow_block(struct btrfs_trans_handle *trans,
228 struct btrfs_root *root, struct extent_buffer *buf,
229 struct extent_buffer *parent, int parent_slot,
230 struct extent_buffer **cow_ret)
231 {
232 u64 search_start;
233 int ret;
234 /*
235 if (trans->transaction != root->fs_info->running_transaction) {
236 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
237 root->fs_info->running_transaction->transid);
238 WARN_ON(1);
239 }
240 */
241 if (trans->transid != root->fs_info->generation) {
242 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
243 root->fs_info->generation);
244 WARN_ON(1);
245 }
246 if (btrfs_header_generation(buf) == trans->transid) {
247 #if 0
248 &&
249 !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
250 #endif
251 *cow_ret = buf;
252 return 0;
253 }
254
255 search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
256 ret = __btrfs_cow_block(trans, root, buf, parent,
257 parent_slot, cow_ret, search_start, 0);
258 return ret;
259 }
260
261 /*
262 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
263 {
264 if (blocknr < other && other - (blocknr + blocksize) < 32768)
265 return 1;
266 if (blocknr > other && blocknr - (other + blocksize) < 32768)
267 return 1;
268 return 0;
269 }
270 */
271
272 /*
273 * compare two keys in a memcmp fashion
274 */
275 int btrfs_comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
276 {
277 struct btrfs_key k1;
278
279 btrfs_disk_key_to_cpu(&k1, disk);
280
281 if (k1.objectid > k2->objectid)
282 return 1;
283 if (k1.objectid < k2->objectid)
284 return -1;
285 if (k1.type > k2->type)
286 return 1;
287 if (k1.type < k2->type)
288 return -1;
289 if (k1.offset > k2->offset)
290 return 1;
291 if (k1.offset < k2->offset)
292 return -1;
293 return 0;
294 }
295
296
297 #if 0
298 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
299 struct btrfs_root *root, struct extent_buffer *parent,
300 int start_slot, int cache_only, u64 *last_ret,
301 struct btrfs_key *progress)
302 {
303 struct extent_buffer *cur;
304 struct extent_buffer *tmp;
305 u64 blocknr;
306 u64 search_start = *last_ret;
307 u64 last_block = 0;
308 u64 other;
309 u32 parent_nritems;
310 int end_slot;
311 int i;
312 int err = 0;
313 int parent_level;
314 int uptodate;
315 u32 blocksize;
316 int progress_passed = 0;
317 struct btrfs_disk_key disk_key;
318
319 parent_level = btrfs_header_level(parent);
320 if (cache_only && parent_level != 1)
321 return 0;
322
323 if (trans->transaction != root->fs_info->running_transaction) {
324 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
325 root->fs_info->running_transaction->transid);
326 WARN_ON(1);
327 }
328 if (trans->transid != root->fs_info->generation) {
329 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
330 root->fs_info->generation);
331 WARN_ON(1);
332 }
333
334 parent_nritems = btrfs_header_nritems(parent);
335 blocksize = btrfs_level_size(root, parent_level - 1);
336 end_slot = parent_nritems;
337
338 if (parent_nritems == 1)
339 return 0;
340
341 for (i = start_slot; i < end_slot; i++) {
342 int close = 1;
343
344 if (!parent->map_token) {
345 map_extent_buffer(parent,
346 btrfs_node_key_ptr_offset(i),
347 sizeof(struct btrfs_key_ptr),
348 &parent->map_token, &parent->kaddr,
349 &parent->map_start, &parent->map_len,
350 KM_USER1);
351 }
352 btrfs_node_key(parent, &disk_key, i);
353 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
354 continue;
355
356 progress_passed = 1;
357 blocknr = btrfs_node_blockptr(parent, i);
358 if (last_block == 0)
359 last_block = blocknr;
360
361 if (i > 0) {
362 other = btrfs_node_blockptr(parent, i - 1);
363 close = close_blocks(blocknr, other, blocksize);
364 }
365 if (close && i < end_slot - 2) {
366 other = btrfs_node_blockptr(parent, i + 1);
367 close = close_blocks(blocknr, other, blocksize);
368 }
369 if (close) {
370 last_block = blocknr;
371 continue;
372 }
373 if (parent->map_token) {
374 unmap_extent_buffer(parent, parent->map_token,
375 KM_USER1);
376 parent->map_token = NULL;
377 }
378
379 cur = btrfs_find_tree_block(root, blocknr, blocksize);
380 if (cur)
381 uptodate = btrfs_buffer_uptodate(cur);
382 else
383 uptodate = 0;
384 if (!cur || !uptodate) {
385 if (cache_only) {
386 free_extent_buffer(cur);
387 continue;
388 }
389 if (!cur) {
390 cur = read_tree_block(root, blocknr,
391 blocksize);
392 } else if (!uptodate) {
393 btrfs_read_buffer(cur);
394 }
395 }
396 if (search_start == 0)
397 search_start = last_block;
398
399 err = __btrfs_cow_block(trans, root, cur, parent, i,
400 &tmp, search_start,
401 min(16 * blocksize,
402 (end_slot - i) * blocksize));
403 if (err) {
404 free_extent_buffer(cur);
405 break;
406 }
407 search_start = tmp->start;
408 last_block = tmp->start;
409 *last_ret = search_start;
410 if (parent_level == 1)
411 btrfs_clear_buffer_defrag(tmp);
412 free_extent_buffer(tmp);
413 }
414 if (parent->map_token) {
415 unmap_extent_buffer(parent, parent->map_token,
416 KM_USER1);
417 parent->map_token = NULL;
418 }
419 return err;
420 }
421 #endif
422
423 /*
424 * The leaf data grows from end-to-front in the node.
425 * this returns the address of the start of the last item,
426 * which is the stop of the leaf data stack
427 */
428 static inline unsigned int leaf_data_end(struct btrfs_root *root,
429 struct extent_buffer *leaf)
430 {
431 u32 nr = btrfs_header_nritems(leaf);
432 if (nr == 0)
433 return BTRFS_LEAF_DATA_SIZE(root);
434 return btrfs_item_offset_nr(leaf, nr - 1);
435 }
436
437 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
438 int level)
439 {
440 struct extent_buffer *parent = NULL;
441 struct extent_buffer *node = path->nodes[level];
442 struct btrfs_disk_key parent_key;
443 struct btrfs_disk_key node_key;
444 int parent_slot;
445 int slot;
446 struct btrfs_key cpukey;
447 u32 nritems = btrfs_header_nritems(node);
448
449 if (path->nodes[level + 1])
450 parent = path->nodes[level + 1];
451
452 slot = path->slots[level];
453 BUG_ON(nritems == 0);
454 if (parent) {
455 parent_slot = path->slots[level + 1];
456 btrfs_node_key(parent, &parent_key, parent_slot);
457 btrfs_node_key(node, &node_key, 0);
458 BUG_ON(memcmp(&parent_key, &node_key,
459 sizeof(struct btrfs_disk_key)));
460 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
461 btrfs_header_bytenr(node));
462 }
463 BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
464 if (slot != 0) {
465 btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
466 btrfs_node_key(node, &node_key, slot);
467 BUG_ON(btrfs_comp_keys(&node_key, &cpukey) <= 0);
468 }
469 if (slot < nritems - 1) {
470 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
471 btrfs_node_key(node, &node_key, slot);
472 BUG_ON(btrfs_comp_keys(&node_key, &cpukey) >= 0);
473 }
474 return 0;
475 }
476
477 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
478 int level)
479 {
480 struct extent_buffer *leaf = path->nodes[level];
481 struct extent_buffer *parent = NULL;
482 int parent_slot;
483 struct btrfs_key cpukey;
484 struct btrfs_disk_key parent_key;
485 struct btrfs_disk_key leaf_key;
486 int slot = path->slots[0];
487
488 u32 nritems = btrfs_header_nritems(leaf);
489
490 if (path->nodes[level + 1])
491 parent = path->nodes[level + 1];
492
493 if (nritems == 0)
494 return 0;
495
496 if (parent) {
497 parent_slot = path->slots[level + 1];
498 btrfs_node_key(parent, &parent_key, parent_slot);
499 btrfs_item_key(leaf, &leaf_key, 0);
500
501 BUG_ON(memcmp(&parent_key, &leaf_key,
502 sizeof(struct btrfs_disk_key)));
503 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
504 btrfs_header_bytenr(leaf));
505 }
506 #if 0
507 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
508 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
509 btrfs_item_key(leaf, &leaf_key, i);
510 if (comp_keys(&leaf_key, &cpukey) >= 0) {
511 btrfs_print_leaf(root, leaf);
512 printk("slot %d offset bad key\n", i);
513 BUG_ON(1);
514 }
515 if (btrfs_item_offset_nr(leaf, i) !=
516 btrfs_item_end_nr(leaf, i + 1)) {
517 btrfs_print_leaf(root, leaf);
518 printk("slot %d offset bad\n", i);
519 BUG_ON(1);
520 }
521 if (i == 0) {
522 if (btrfs_item_offset_nr(leaf, i) +
523 btrfs_item_size_nr(leaf, i) !=
524 BTRFS_LEAF_DATA_SIZE(root)) {
525 btrfs_print_leaf(root, leaf);
526 printk("slot %d first offset bad\n", i);
527 BUG_ON(1);
528 }
529 }
530 }
531 if (nritems > 0) {
532 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
533 btrfs_print_leaf(root, leaf);
534 printk("slot %d bad size \n", nritems - 1);
535 BUG_ON(1);
536 }
537 }
538 #endif
539 if (slot != 0 && slot < nritems - 1) {
540 btrfs_item_key(leaf, &leaf_key, slot);
541 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
542 if (btrfs_comp_keys(&leaf_key, &cpukey) <= 0) {
543 btrfs_print_leaf(root, leaf);
544 printk("slot %d offset bad key\n", slot);
545 BUG_ON(1);
546 }
547 if (btrfs_item_offset_nr(leaf, slot - 1) !=
548 btrfs_item_end_nr(leaf, slot)) {
549 btrfs_print_leaf(root, leaf);
550 printk("slot %d offset bad\n", slot);
551 BUG_ON(1);
552 }
553 }
554 if (slot < nritems - 1) {
555 btrfs_item_key(leaf, &leaf_key, slot);
556 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
557 BUG_ON(btrfs_comp_keys(&leaf_key, &cpukey) >= 0);
558 if (btrfs_item_offset_nr(leaf, slot) !=
559 btrfs_item_end_nr(leaf, slot + 1)) {
560 btrfs_print_leaf(root, leaf);
561 printk("slot %d offset bad\n", slot);
562 BUG_ON(1);
563 }
564 }
565 BUG_ON(btrfs_item_offset_nr(leaf, 0) +
566 btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
567 return 0;
568 }
569
570 static int noinline check_block(struct btrfs_root *root,
571 struct btrfs_path *path, int level)
572 {
573 return 0;
574 #if 0
575 struct extent_buffer *buf = path->nodes[level];
576
577 if (memcmp_extent_buffer(buf, root->fs_info->fsid,
578 (unsigned long)btrfs_header_fsid(buf),
579 BTRFS_FSID_SIZE)) {
580 printk("warning bad block %Lu\n", buf->start);
581 return 1;
582 }
583 #endif
584 if (level == 0)
585 return check_leaf(root, path, level);
586 return check_node(root, path, level);
587 }
588
589 /*
590 * search for key in the extent_buffer. The items start at offset p,
591 * and they are item_size apart. There are 'max' items in p.
592 *
593 * the slot in the array is returned via slot, and it points to
594 * the place where you would insert key if it is not found in
595 * the array.
596 *
597 * slot may point to max if the key is bigger than all of the keys
598 */
599 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
600 int item_size, struct btrfs_key *key,
601 int max, int *slot)
602 {
603 int low = 0;
604 int high = max;
605 int mid;
606 int ret;
607 unsigned long offset;
608 struct btrfs_disk_key *tmp;
609
610 while(low < high) {
611 mid = (low + high) / 2;
612 offset = p + mid * item_size;
613
614 tmp = (struct btrfs_disk_key *)(eb->data + offset);
615 ret = btrfs_comp_keys(tmp, key);
616
617 if (ret < 0)
618 low = mid + 1;
619 else if (ret > 0)
620 high = mid;
621 else {
622 *slot = mid;
623 return 0;
624 }
625 }
626 *slot = low;
627 return 1;
628 }
629
630 /*
631 * simple bin_search frontend that does the right thing for
632 * leaves vs nodes
633 */
634 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
635 int level, int *slot)
636 {
637 if (level == 0) {
638 return generic_bin_search(eb,
639 offsetof(struct btrfs_leaf, items),
640 sizeof(struct btrfs_item),
641 key, btrfs_header_nritems(eb),
642 slot);
643 } else {
644 return generic_bin_search(eb,
645 offsetof(struct btrfs_node, ptrs),
646 sizeof(struct btrfs_key_ptr),
647 key, btrfs_header_nritems(eb),
648 slot);
649 }
650 return -1;
651 }
652
653 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
654 struct extent_buffer *parent, int slot)
655 {
656 if (slot < 0)
657 return NULL;
658 if (slot >= btrfs_header_nritems(parent))
659 return NULL;
660 return read_tree_block(root, btrfs_node_blockptr(parent, slot),
661 btrfs_level_size(root, btrfs_header_level(parent) - 1));
662 }
663
664 static int balance_level(struct btrfs_trans_handle *trans,
665 struct btrfs_root *root,
666 struct btrfs_path *path, int level)
667 {
668 struct extent_buffer *right = NULL;
669 struct extent_buffer *mid;
670 struct extent_buffer *left = NULL;
671 struct extent_buffer *parent = NULL;
672 int ret = 0;
673 int wret;
674 int pslot;
675 int orig_slot = path->slots[level];
676 int err_on_enospc = 0;
677 u64 orig_ptr;
678
679 if (level == 0)
680 return 0;
681
682 mid = path->nodes[level];
683 WARN_ON(btrfs_header_generation(mid) != trans->transid);
684
685 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
686
687 if (level < BTRFS_MAX_LEVEL - 1)
688 parent = path->nodes[level + 1];
689 pslot = path->slots[level + 1];
690
691 /*
692 * deal with the case where there is only one pointer in the root
693 * by promoting the node below to a root
694 */
695 if (!parent) {
696 struct extent_buffer *child;
697
698 if (btrfs_header_nritems(mid) != 1)
699 return 0;
700
701 /* promote the child to a root */
702 child = read_node_slot(root, mid, 0);
703 BUG_ON(!child);
704 ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
705 BUG_ON(ret);
706
707 root->node = child;
708 add_root_to_dirty_list(root);
709 path->nodes[level] = NULL;
710 clean_tree_block(trans, root, mid);
711 wait_on_tree_block_writeback(root, mid);
712 /* once for the path */
713 free_extent_buffer(mid);
714 ret = btrfs_free_extent(trans, root, mid->start, mid->len,
715 root->root_key.objectid,
716 btrfs_header_generation(mid), 0, 0, 1);
717 /* once for the root ptr */
718 free_extent_buffer(mid);
719 return ret;
720 }
721 if (btrfs_header_nritems(mid) >
722 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
723 return 0;
724
725 if (btrfs_header_nritems(mid) < 2)
726 err_on_enospc = 1;
727
728 left = read_node_slot(root, parent, pslot - 1);
729 if (left) {
730 wret = btrfs_cow_block(trans, root, left,
731 parent, pslot - 1, &left);
732 if (wret) {
733 ret = wret;
734 goto enospc;
735 }
736 }
737 right = read_node_slot(root, parent, pslot + 1);
738 if (right) {
739 wret = btrfs_cow_block(trans, root, right,
740 parent, pslot + 1, &right);
741 if (wret) {
742 ret = wret;
743 goto enospc;
744 }
745 }
746
747 /* first, try to make some room in the middle buffer */
748 if (left) {
749 orig_slot += btrfs_header_nritems(left);
750 wret = push_node_left(trans, root, left, mid);
751 if (wret < 0)
752 ret = wret;
753 if (btrfs_header_nritems(mid) < 2)
754 err_on_enospc = 1;
755 }
756
757 /*
758 * then try to empty the right most buffer into the middle
759 */
760 if (right) {
761 wret = push_node_left(trans, root, mid, right);
762 if (wret < 0 && wret != -ENOSPC)
763 ret = wret;
764 if (btrfs_header_nritems(right) == 0) {
765 u64 bytenr = right->start;
766 u64 generation = btrfs_header_generation(parent);
767 u32 blocksize = right->len;
768
769 clean_tree_block(trans, root, right);
770 wait_on_tree_block_writeback(root, right);
771 free_extent_buffer(right);
772 right = NULL;
773 wret = del_ptr(trans, root, path, level + 1, pslot +
774 1);
775 if (wret)
776 ret = wret;
777 wret = btrfs_free_extent(trans, root, bytenr,
778 blocksize,
779 btrfs_header_owner(parent),
780 generation, 0, 0, 1);
781 if (wret)
782 ret = wret;
783 } else {
784 struct btrfs_disk_key right_key;
785 btrfs_node_key(right, &right_key, 0);
786 btrfs_set_node_key(parent, &right_key, pslot + 1);
787 btrfs_mark_buffer_dirty(parent);
788 }
789 }
790 if (btrfs_header_nritems(mid) == 1) {
791 /*
792 * we're not allowed to leave a node with one item in the
793 * tree during a delete. A deletion from lower in the tree
794 * could try to delete the only pointer in this node.
795 * So, pull some keys from the left.
796 * There has to be a left pointer at this point because
797 * otherwise we would have pulled some pointers from the
798 * right
799 */
800 BUG_ON(!left);
801 wret = balance_node_right(trans, root, mid, left);
802 if (wret < 0) {
803 ret = wret;
804 goto enospc;
805 }
806 BUG_ON(wret == 1);
807 }
808 if (btrfs_header_nritems(mid) == 0) {
809 /* we've managed to empty the middle node, drop it */
810 u64 root_gen = btrfs_header_generation(parent);
811 u64 bytenr = mid->start;
812 u32 blocksize = mid->len;
813 clean_tree_block(trans, root, mid);
814 wait_on_tree_block_writeback(root, mid);
815 free_extent_buffer(mid);
816 mid = NULL;
817 wret = del_ptr(trans, root, path, level + 1, pslot);
818 if (wret)
819 ret = wret;
820 wret = btrfs_free_extent(trans, root, bytenr, blocksize,
821 btrfs_header_owner(parent),
822 root_gen, 0, 0, 1);
823 if (wret)
824 ret = wret;
825 } else {
826 /* update the parent key to reflect our changes */
827 struct btrfs_disk_key mid_key;
828 btrfs_node_key(mid, &mid_key, 0);
829 btrfs_set_node_key(parent, &mid_key, pslot);
830 btrfs_mark_buffer_dirty(parent);
831 }
832
833 /* update the path */
834 if (left) {
835 if (btrfs_header_nritems(left) > orig_slot) {
836 extent_buffer_get(left);
837 path->nodes[level] = left;
838 path->slots[level + 1] -= 1;
839 path->slots[level] = orig_slot;
840 if (mid)
841 free_extent_buffer(mid);
842 } else {
843 orig_slot -= btrfs_header_nritems(left);
844 path->slots[level] = orig_slot;
845 }
846 }
847 /* double check we haven't messed things up */
848 check_block(root, path, level);
849 if (orig_ptr !=
850 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
851 BUG();
852 enospc:
853 if (right)
854 free_extent_buffer(right);
855 if (left)
856 free_extent_buffer(left);
857 return ret;
858 }
859
860 /* returns zero if the push worked, non-zero otherwise */
861 static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
862 struct btrfs_root *root,
863 struct btrfs_path *path, int level)
864 {
865 struct extent_buffer *right = NULL;
866 struct extent_buffer *mid;
867 struct extent_buffer *left = NULL;
868 struct extent_buffer *parent = NULL;
869 int ret = 0;
870 int wret;
871 int pslot;
872 int orig_slot = path->slots[level];
873 u64 orig_ptr;
874
875 if (level == 0)
876 return 1;
877
878 mid = path->nodes[level];
879 WARN_ON(btrfs_header_generation(mid) != trans->transid);
880 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
881
882 if (level < BTRFS_MAX_LEVEL - 1)
883 parent = path->nodes[level + 1];
884 pslot = path->slots[level + 1];
885
886 if (!parent)
887 return 1;
888
889 left = read_node_slot(root, parent, pslot - 1);
890
891 /* first, try to make some room in the middle buffer */
892 if (left) {
893 u32 left_nr;
894 left_nr = btrfs_header_nritems(left);
895 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
896 wret = 1;
897 } else {
898 ret = btrfs_cow_block(trans, root, left, parent,
899 pslot - 1, &left);
900 if (ret)
901 wret = 1;
902 else {
903 wret = push_node_left(trans, root,
904 left, mid);
905 }
906 }
907 if (wret < 0)
908 ret = wret;
909 if (wret == 0) {
910 struct btrfs_disk_key disk_key;
911 orig_slot += left_nr;
912 btrfs_node_key(mid, &disk_key, 0);
913 btrfs_set_node_key(parent, &disk_key, pslot);
914 btrfs_mark_buffer_dirty(parent);
915 if (btrfs_header_nritems(left) > orig_slot) {
916 path->nodes[level] = left;
917 path->slots[level + 1] -= 1;
918 path->slots[level] = orig_slot;
919 free_extent_buffer(mid);
920 } else {
921 orig_slot -=
922 btrfs_header_nritems(left);
923 path->slots[level] = orig_slot;
924 free_extent_buffer(left);
925 }
926 return 0;
927 }
928 free_extent_buffer(left);
929 }
930 right= read_node_slot(root, parent, pslot + 1);
931
932 /*
933 * then try to empty the right most buffer into the middle
934 */
935 if (right) {
936 u32 right_nr;
937 right_nr = btrfs_header_nritems(right);
938 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
939 wret = 1;
940 } else {
941 ret = btrfs_cow_block(trans, root, right,
942 parent, pslot + 1,
943 &right);
944 if (ret)
945 wret = 1;
946 else {
947 wret = balance_node_right(trans, root,
948 right, mid);
949 }
950 }
951 if (wret < 0)
952 ret = wret;
953 if (wret == 0) {
954 struct btrfs_disk_key disk_key;
955
956 btrfs_node_key(right, &disk_key, 0);
957 btrfs_set_node_key(parent, &disk_key, pslot + 1);
958 btrfs_mark_buffer_dirty(parent);
959
960 if (btrfs_header_nritems(mid) <= orig_slot) {
961 path->nodes[level] = right;
962 path->slots[level + 1] += 1;
963 path->slots[level] = orig_slot -
964 btrfs_header_nritems(mid);
965 free_extent_buffer(mid);
966 } else {
967 free_extent_buffer(right);
968 }
969 return 0;
970 }
971 free_extent_buffer(right);
972 }
973 return 1;
974 }
975
976 /*
977 * readahead one full node of leaves
978 */
979 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
980 int level, int slot, u64 objectid)
981 {
982 struct extent_buffer *node;
983 struct btrfs_disk_key disk_key;
984 u32 nritems;
985 u64 search;
986 u64 lowest_read;
987 u64 highest_read;
988 u64 nread = 0;
989 int direction = path->reada;
990 struct extent_buffer *eb;
991 u32 nr;
992 u32 blocksize;
993 u32 nscan = 0;
994
995 if (level != 1)
996 return;
997
998 if (!path->nodes[level])
999 return;
1000
1001 node = path->nodes[level];
1002 search = btrfs_node_blockptr(node, slot);
1003 blocksize = btrfs_level_size(root, level - 1);
1004 eb = btrfs_find_tree_block(root, search, blocksize);
1005 if (eb) {
1006 free_extent_buffer(eb);
1007 return;
1008 }
1009
1010 highest_read = search;
1011 lowest_read = search;
1012
1013 nritems = btrfs_header_nritems(node);
1014 nr = slot;
1015 while(1) {
1016 if (direction < 0) {
1017 if (nr == 0)
1018 break;
1019 nr--;
1020 } else if (direction > 0) {
1021 nr++;
1022 if (nr >= nritems)
1023 break;
1024 }
1025 if (path->reada < 0 && objectid) {
1026 btrfs_node_key(node, &disk_key, nr);
1027 if (btrfs_disk_key_objectid(&disk_key) != objectid)
1028 break;
1029 }
1030 search = btrfs_node_blockptr(node, nr);
1031 if ((search >= lowest_read && search <= highest_read) ||
1032 (search < lowest_read && lowest_read - search <= 32768) ||
1033 (search > highest_read && search - highest_read <= 32768)) {
1034 readahead_tree_block(root, search, blocksize);
1035 nread += blocksize;
1036 }
1037 nscan++;
1038 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
1039 break;
1040 if(nread > (1024 * 1024) || nscan > 128)
1041 break;
1042
1043 if (search < lowest_read)
1044 lowest_read = search;
1045 if (search > highest_read)
1046 highest_read = search;
1047 }
1048 }
1049
1050 /*
1051 * look for key in the tree. path is filled in with nodes along the way
1052 * if key is found, we return zero and you can find the item in the leaf
1053 * level of the path (level 0)
1054 *
1055 * If the key isn't found, the path points to the slot where it should
1056 * be inserted, and 1 is returned. If there are other errors during the
1057 * search a negative error number is returned.
1058 *
1059 * if ins_len > 0, nodes and leaves will be split as we walk down the
1060 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
1061 * possible)
1062 */
1063 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
1064 *root, struct btrfs_key *key, struct btrfs_path *p, int
1065 ins_len, int cow)
1066 {
1067 struct extent_buffer *b;
1068 u64 bytenr;
1069 u64 ptr_gen;
1070 int slot;
1071 int ret;
1072 int level;
1073 int should_reada = p->reada;
1074 u8 lowest_level = 0;
1075
1076 lowest_level = p->lowest_level;
1077 WARN_ON(lowest_level && ins_len);
1078 WARN_ON(p->nodes[0] != NULL);
1079 /*
1080 WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
1081 */
1082 again:
1083 b = root->node;
1084 extent_buffer_get(b);
1085 while (b) {
1086 level = btrfs_header_level(b);
1087 if (cow) {
1088 int wret;
1089 wret = btrfs_cow_block(trans, root, b,
1090 p->nodes[level + 1],
1091 p->slots[level + 1],
1092 &b);
1093 if (wret) {
1094 free_extent_buffer(b);
1095 return wret;
1096 }
1097 }
1098 BUG_ON(!cow && ins_len);
1099 if (level != btrfs_header_level(b))
1100 WARN_ON(1);
1101 level = btrfs_header_level(b);
1102 p->nodes[level] = b;
1103 ret = check_block(root, p, level);
1104 if (ret)
1105 return -1;
1106 ret = bin_search(b, key, level, &slot);
1107 if (level != 0) {
1108 if (ret && slot > 0)
1109 slot -= 1;
1110 p->slots[level] = slot;
1111 if (ins_len > 0 && btrfs_header_nritems(b) >=
1112 BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1113 int sret = split_node(trans, root, p, level);
1114 BUG_ON(sret > 0);
1115 if (sret)
1116 return sret;
1117 b = p->nodes[level];
1118 slot = p->slots[level];
1119 } else if (ins_len < 0) {
1120 int sret = balance_level(trans, root, p,
1121 level);
1122 if (sret)
1123 return sret;
1124 b = p->nodes[level];
1125 if (!b) {
1126 btrfs_release_path(NULL, p);
1127 goto again;
1128 }
1129 slot = p->slots[level];
1130 BUG_ON(btrfs_header_nritems(b) == 1);
1131 }
1132 /* this is only true while dropping a snapshot */
1133 if (level == lowest_level)
1134 break;
1135 bytenr = btrfs_node_blockptr(b, slot);
1136 ptr_gen = btrfs_node_ptr_generation(b, slot);
1137 if (should_reada)
1138 reada_for_search(root, p, level, slot,
1139 key->objectid);
1140 b = read_tree_block(root, bytenr,
1141 btrfs_level_size(root, level - 1));
1142 if (ptr_gen != btrfs_header_generation(b)) {
1143 printk("block %llu bad gen wanted %llu "
1144 "found %llu\n",
1145 (unsigned long long)b->start,
1146 (unsigned long long)ptr_gen,
1147 (unsigned long long)btrfs_header_generation(b));
1148 }
1149 } else {
1150 p->slots[level] = slot;
1151 if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1152 sizeof(struct btrfs_item) + ins_len) {
1153 int sret = split_leaf(trans, root, key,
1154 p, ins_len, ret == 0);
1155 BUG_ON(sret > 0);
1156 if (sret)
1157 return sret;
1158 }
1159 return ret;
1160 }
1161 }
1162 return 1;
1163 }
1164
1165 /*
1166 * adjust the pointers going up the tree, starting at level
1167 * making sure the right key of each node is points to 'key'.
1168 * This is used after shifting pointers to the left, so it stops
1169 * fixing up pointers when a given leaf/node is not in slot 0 of the
1170 * higher levels
1171 *
1172 * If this fails to write a tree block, it returns -1, but continues
1173 * fixing up the blocks in ram so the tree is consistent.
1174 */
1175 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1176 struct btrfs_root *root, struct btrfs_path *path,
1177 struct btrfs_disk_key *key, int level)
1178 {
1179 int i;
1180 int ret = 0;
1181 struct extent_buffer *t;
1182
1183 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1184 int tslot = path->slots[i];
1185 if (!path->nodes[i])
1186 break;
1187 t = path->nodes[i];
1188 btrfs_set_node_key(t, key, tslot);
1189 btrfs_mark_buffer_dirty(path->nodes[i]);
1190 if (tslot != 0)
1191 break;
1192 }
1193 return ret;
1194 }
1195
1196 /*
1197 * try to push data from one node into the next node left in the
1198 * tree.
1199 *
1200 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1201 * error, and > 0 if there was no room in the left hand block.
1202 */
1203 static int push_node_left(struct btrfs_trans_handle *trans,
1204 struct btrfs_root *root, struct extent_buffer *dst,
1205 struct extent_buffer *src)
1206 {
1207 int push_items = 0;
1208 int src_nritems;
1209 int dst_nritems;
1210 int ret = 0;
1211
1212 src_nritems = btrfs_header_nritems(src);
1213 dst_nritems = btrfs_header_nritems(dst);
1214 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1215 WARN_ON(btrfs_header_generation(src) != trans->transid);
1216 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1217
1218 if (push_items <= 0) {
1219 return 1;
1220 }
1221
1222 if (src_nritems < push_items)
1223 push_items = src_nritems;
1224
1225 copy_extent_buffer(dst, src,
1226 btrfs_node_key_ptr_offset(dst_nritems),
1227 btrfs_node_key_ptr_offset(0),
1228 push_items * sizeof(struct btrfs_key_ptr));
1229
1230 if (push_items < src_nritems) {
1231 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1232 btrfs_node_key_ptr_offset(push_items),
1233 (src_nritems - push_items) *
1234 sizeof(struct btrfs_key_ptr));
1235 }
1236 btrfs_set_header_nritems(src, src_nritems - push_items);
1237 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1238 btrfs_mark_buffer_dirty(src);
1239 btrfs_mark_buffer_dirty(dst);
1240 return ret;
1241 }
1242
1243 /*
1244 * try to push data from one node into the next node right in the
1245 * tree.
1246 *
1247 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1248 * error, and > 0 if there was no room in the right hand block.
1249 *
1250 * this will only push up to 1/2 the contents of the left node over
1251 */
1252 static int balance_node_right(struct btrfs_trans_handle *trans,
1253 struct btrfs_root *root,
1254 struct extent_buffer *dst,
1255 struct extent_buffer *src)
1256 {
1257 int push_items = 0;
1258 int max_push;
1259 int src_nritems;
1260 int dst_nritems;
1261 int ret = 0;
1262
1263 WARN_ON(btrfs_header_generation(src) != trans->transid);
1264 WARN_ON(btrfs_header_generation(dst) != trans->transid);
1265
1266 src_nritems = btrfs_header_nritems(src);
1267 dst_nritems = btrfs_header_nritems(dst);
1268 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1269 if (push_items <= 0)
1270 return 1;
1271
1272 max_push = src_nritems / 2 + 1;
1273 /* don't try to empty the node */
1274 if (max_push >= src_nritems)
1275 return 1;
1276
1277 if (max_push < push_items)
1278 push_items = max_push;
1279
1280 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1281 btrfs_node_key_ptr_offset(0),
1282 (dst_nritems) *
1283 sizeof(struct btrfs_key_ptr));
1284
1285 copy_extent_buffer(dst, src,
1286 btrfs_node_key_ptr_offset(0),
1287 btrfs_node_key_ptr_offset(src_nritems - push_items),
1288 push_items * sizeof(struct btrfs_key_ptr));
1289
1290 btrfs_set_header_nritems(src, src_nritems - push_items);
1291 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1292
1293 btrfs_mark_buffer_dirty(src);
1294 btrfs_mark_buffer_dirty(dst);
1295 return ret;
1296 }
1297
1298 /*
1299 * helper function to insert a new root level in the tree.
1300 * A new node is allocated, and a single item is inserted to
1301 * point to the existing root
1302 *
1303 * returns zero on success or < 0 on failure.
1304 */
1305 static int noinline insert_new_root(struct btrfs_trans_handle *trans,
1306 struct btrfs_root *root,
1307 struct btrfs_path *path, int level)
1308 {
1309 u64 root_gen;
1310 u64 lower_gen;
1311 struct extent_buffer *lower;
1312 struct extent_buffer *c;
1313 struct btrfs_disk_key lower_key;
1314
1315 BUG_ON(path->nodes[level]);
1316 BUG_ON(path->nodes[level-1] != root->node);
1317
1318 if (root->ref_cows)
1319 root_gen = trans->transid;
1320 else
1321 root_gen = 0;
1322
1323 lower = path->nodes[level-1];
1324 if (level == 1)
1325 btrfs_item_key(lower, &lower_key, 0);
1326 else
1327 btrfs_node_key(lower, &lower_key, 0);
1328
1329 c = __btrfs_alloc_free_block(trans, root, root->nodesize,
1330 root->root_key.objectid,
1331 root_gen, lower_key.objectid, level,
1332 root->node->start, 0);
1333 if (IS_ERR(c))
1334 return PTR_ERR(c);
1335 memset_extent_buffer(c, 0, 0, root->nodesize);
1336 btrfs_set_header_nritems(c, 1);
1337 btrfs_set_header_level(c, level);
1338 btrfs_set_header_bytenr(c, c->start);
1339 btrfs_set_header_generation(c, trans->transid);
1340 btrfs_set_header_owner(c, root->root_key.objectid);
1341
1342 write_extent_buffer(c, root->fs_info->fsid,
1343 (unsigned long)btrfs_header_fsid(c),
1344 BTRFS_FSID_SIZE);
1345 btrfs_set_node_key(c, &lower_key, 0);
1346 btrfs_set_node_blockptr(c, 0, lower->start);
1347 lower_gen = btrfs_header_generation(lower);
1348 WARN_ON(lower_gen == 0);
1349
1350 btrfs_set_node_ptr_generation(c, 0, lower_gen);
1351
1352 btrfs_mark_buffer_dirty(c);
1353
1354 /* the super has an extra ref to root->node */
1355 free_extent_buffer(root->node);
1356 root->node = c;
1357 add_root_to_dirty_list(root);
1358 extent_buffer_get(c);
1359 path->nodes[level] = c;
1360 path->slots[level] = 0;
1361
1362 if (root->ref_cows && lower_gen != trans->transid) {
1363 struct btrfs_path *back_path = btrfs_alloc_path();
1364 int ret;
1365 ret = btrfs_insert_extent_backref(trans,
1366 root->fs_info->extent_root,
1367 path, lower->start,
1368 root->root_key.objectid,
1369 trans->transid, 0, 0);
1370 BUG_ON(ret);
1371 btrfs_free_path(back_path);
1372 }
1373 return 0;
1374 }
1375
1376 /*
1377 * worker function to insert a single pointer in a node.
1378 * the node should have enough room for the pointer already
1379 *
1380 * slot and level indicate where you want the key to go, and
1381 * blocknr is the block the key points to.
1382 *
1383 * returns zero on success and < 0 on any error
1384 */
1385 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1386 *root, struct btrfs_path *path, struct btrfs_disk_key
1387 *key, u64 bytenr, int slot, int level)
1388 {
1389 struct extent_buffer *lower;
1390 int nritems;
1391
1392 BUG_ON(!path->nodes[level]);
1393 lower = path->nodes[level];
1394 nritems = btrfs_header_nritems(lower);
1395 if (slot > nritems)
1396 BUG();
1397 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1398 BUG();
1399 if (slot != nritems) {
1400 memmove_extent_buffer(lower,
1401 btrfs_node_key_ptr_offset(slot + 1),
1402 btrfs_node_key_ptr_offset(slot),
1403 (nritems - slot) * sizeof(struct btrfs_key_ptr));
1404 }
1405 btrfs_set_node_key(lower, key, slot);
1406 btrfs_set_node_blockptr(lower, slot, bytenr);
1407 WARN_ON(trans->transid == 0);
1408 btrfs_set_node_ptr_generation(lower, slot, trans->transid);
1409 btrfs_set_header_nritems(lower, nritems + 1);
1410 btrfs_mark_buffer_dirty(lower);
1411 return 0;
1412 }
1413
1414 /*
1415 * split the node at the specified level in path in two.
1416 * The path is corrected to point to the appropriate node after the split
1417 *
1418 * Before splitting this tries to make some room in the node by pushing
1419 * left and right, if either one works, it returns right away.
1420 *
1421 * returns 0 on success and < 0 on failure
1422 */
1423 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1424 *root, struct btrfs_path *path, int level)
1425 {
1426 u64 root_gen;
1427 struct extent_buffer *c;
1428 struct extent_buffer *split;
1429 struct btrfs_disk_key disk_key;
1430 int mid;
1431 int ret;
1432 int wret;
1433 u32 c_nritems;
1434
1435 c = path->nodes[level];
1436 WARN_ON(btrfs_header_generation(c) != trans->transid);
1437 if (c == root->node) {
1438 /* trying to split the root, lets make a new one */
1439 ret = insert_new_root(trans, root, path, level + 1);
1440 if (ret)
1441 return ret;
1442 } else {
1443 ret = push_nodes_for_insert(trans, root, path, level);
1444 c = path->nodes[level];
1445 if (!ret && btrfs_header_nritems(c) <
1446 BTRFS_NODEPTRS_PER_BLOCK(root) - 1)
1447 return 0;
1448 if (ret < 0)
1449 return ret;
1450 }
1451
1452 c_nritems = btrfs_header_nritems(c);
1453 if (root->ref_cows)
1454 root_gen = trans->transid;
1455 else
1456 root_gen = 0;
1457
1458 btrfs_node_key(c, &disk_key, 0);
1459 split = __btrfs_alloc_free_block(trans, root, root->nodesize,
1460 root->root_key.objectid,
1461 root_gen,
1462 btrfs_disk_key_objectid(&disk_key),
1463 level, c->start, 0);
1464 if (IS_ERR(split))
1465 return PTR_ERR(split);
1466
1467 btrfs_set_header_flags(split, btrfs_header_flags(c));
1468 btrfs_set_header_level(split, btrfs_header_level(c));
1469 btrfs_set_header_bytenr(split, split->start);
1470 btrfs_set_header_generation(split, trans->transid);
1471 btrfs_set_header_owner(split, root->root_key.objectid);
1472 btrfs_set_header_flags(split, 0);
1473 write_extent_buffer(split, root->fs_info->fsid,
1474 (unsigned long)btrfs_header_fsid(split),
1475 BTRFS_FSID_SIZE);
1476
1477 mid = (c_nritems + 1) / 2;
1478
1479 copy_extent_buffer(split, c,
1480 btrfs_node_key_ptr_offset(0),
1481 btrfs_node_key_ptr_offset(mid),
1482 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1483 btrfs_set_header_nritems(split, c_nritems - mid);
1484 btrfs_set_header_nritems(c, mid);
1485 ret = 0;
1486
1487 btrfs_mark_buffer_dirty(c);
1488 btrfs_mark_buffer_dirty(split);
1489
1490 btrfs_node_key(split, &disk_key, 0);
1491 wret = insert_ptr(trans, root, path, &disk_key, split->start,
1492 path->slots[level + 1] + 1,
1493 level + 1);
1494 if (wret)
1495 ret = wret;
1496
1497 if (path->slots[level] >= mid) {
1498 path->slots[level] -= mid;
1499 free_extent_buffer(c);
1500 path->nodes[level] = split;
1501 path->slots[level + 1] += 1;
1502 } else {
1503 free_extent_buffer(split);
1504 }
1505 return ret;
1506 }
1507
1508 /*
1509 * how many bytes are required to store the items in a leaf. start
1510 * and nr indicate which items in the leaf to check. This totals up the
1511 * space used both by the item structs and the item data
1512 */
1513 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1514 {
1515 int data_len;
1516 int nritems = btrfs_header_nritems(l);
1517 int end = min(nritems, start + nr) - 1;
1518
1519 if (!nr)
1520 return 0;
1521 data_len = btrfs_item_end_nr(l, start);
1522 data_len = data_len - btrfs_item_offset_nr(l, end);
1523 data_len += sizeof(struct btrfs_item) * nr;
1524 WARN_ON(data_len < 0);
1525 return data_len;
1526 }
1527
1528 /*
1529 * The space between the end of the leaf items and
1530 * the start of the leaf data. IOW, how much room
1531 * the leaf has left for both items and data
1532 */
1533 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1534 {
1535 int nritems = btrfs_header_nritems(leaf);
1536 int ret;
1537 ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1538 if (ret < 0) {
1539 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1540 ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
1541 leaf_space_used(leaf, 0, nritems), nritems);
1542 }
1543 return ret;
1544 }
1545
1546 /*
1547 * push some data in the path leaf to the right, trying to free up at
1548 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1549 *
1550 * returns 1 if the push failed because the other node didn't have enough
1551 * room, 0 if everything worked out and < 0 if there were major errors.
1552 */
1553 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1554 *root, struct btrfs_path *path, int data_size,
1555 int empty)
1556 {
1557 struct extent_buffer *left = path->nodes[0];
1558 struct extent_buffer *right;
1559 struct extent_buffer *upper;
1560 struct btrfs_disk_key disk_key;
1561 int slot;
1562 u32 i;
1563 int free_space;
1564 int push_space = 0;
1565 int push_items = 0;
1566 struct btrfs_item *item;
1567 u32 left_nritems;
1568 u32 nr;
1569 u32 right_nritems;
1570 u32 data_end;
1571 u32 this_item_size;
1572 int ret;
1573
1574 slot = path->slots[1];
1575 if (!path->nodes[1]) {
1576 return 1;
1577 }
1578 upper = path->nodes[1];
1579 if (slot >= btrfs_header_nritems(upper) - 1)
1580 return 1;
1581
1582 right = read_tree_block(root, btrfs_node_blockptr(upper, slot + 1),
1583 root->leafsize);
1584 free_space = btrfs_leaf_free_space(root, right);
1585 if (free_space < data_size + sizeof(struct btrfs_item)) {
1586 free_extent_buffer(right);
1587 return 1;
1588 }
1589
1590 /* cow and double check */
1591 ret = btrfs_cow_block(trans, root, right, upper,
1592 slot + 1, &right);
1593 if (ret) {
1594 free_extent_buffer(right);
1595 return 1;
1596 }
1597 free_space = btrfs_leaf_free_space(root, right);
1598 if (free_space < data_size + sizeof(struct btrfs_item)) {
1599 free_extent_buffer(right);
1600 return 1;
1601 }
1602
1603 left_nritems = btrfs_header_nritems(left);
1604 if (left_nritems == 0) {
1605 free_extent_buffer(right);
1606 return 1;
1607 }
1608
1609 if (empty)
1610 nr = 0;
1611 else
1612 nr = 1;
1613
1614 i = left_nritems - 1;
1615 while (i >= nr) {
1616 item = btrfs_item_nr(left, i);
1617
1618 if (path->slots[0] == i)
1619 push_space += data_size + sizeof(*item);
1620
1621 this_item_size = btrfs_item_size(left, item);
1622 if (this_item_size + sizeof(*item) + push_space > free_space)
1623 break;
1624 push_items++;
1625 push_space += this_item_size + sizeof(*item);
1626 if (i == 0)
1627 break;
1628 i--;
1629 }
1630
1631 if (push_items == 0) {
1632 free_extent_buffer(right);
1633 return 1;
1634 }
1635
1636 if (!empty && push_items == left_nritems)
1637 WARN_ON(1);
1638
1639 /* push left to right */
1640 right_nritems = btrfs_header_nritems(right);
1641
1642 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1643 push_space -= leaf_data_end(root, left);
1644
1645 /* make room in the right data area */
1646 data_end = leaf_data_end(root, right);
1647 memmove_extent_buffer(right,
1648 btrfs_leaf_data(right) + data_end - push_space,
1649 btrfs_leaf_data(right) + data_end,
1650 BTRFS_LEAF_DATA_SIZE(root) - data_end);
1651
1652 /* copy from the left data area */
1653 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1654 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1655 btrfs_leaf_data(left) + leaf_data_end(root, left),
1656 push_space);
1657
1658 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1659 btrfs_item_nr_offset(0),
1660 right_nritems * sizeof(struct btrfs_item));
1661
1662 /* copy the items from left to right */
1663 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1664 btrfs_item_nr_offset(left_nritems - push_items),
1665 push_items * sizeof(struct btrfs_item));
1666
1667 /* update the item pointers */
1668 right_nritems += push_items;
1669 btrfs_set_header_nritems(right, right_nritems);
1670 push_space = BTRFS_LEAF_DATA_SIZE(root);
1671 for (i = 0; i < right_nritems; i++) {
1672 item = btrfs_item_nr(right, i);
1673 push_space -= btrfs_item_size(right, item);
1674 btrfs_set_item_offset(right, item, push_space);
1675 }
1676
1677 left_nritems -= push_items;
1678 btrfs_set_header_nritems(left, left_nritems);
1679
1680 if (left_nritems)
1681 btrfs_mark_buffer_dirty(left);
1682 btrfs_mark_buffer_dirty(right);
1683
1684 btrfs_item_key(right, &disk_key, 0);
1685 btrfs_set_node_key(upper, &disk_key, slot + 1);
1686 btrfs_mark_buffer_dirty(upper);
1687
1688 /* then fixup the leaf pointer in the path */
1689 if (path->slots[0] >= left_nritems) {
1690 path->slots[0] -= left_nritems;
1691 free_extent_buffer(path->nodes[0]);
1692 path->nodes[0] = right;
1693 path->slots[1] += 1;
1694 } else {
1695 free_extent_buffer(right);
1696 }
1697 return 0;
1698 }
1699 /*
1700 * push some data in the path leaf to the left, trying to free up at
1701 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1702 */
1703 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1704 *root, struct btrfs_path *path, int data_size,
1705 int empty)
1706 {
1707 struct btrfs_disk_key disk_key;
1708 struct extent_buffer *right = path->nodes[0];
1709 struct extent_buffer *left;
1710 int slot;
1711 int i;
1712 int free_space;
1713 int push_space = 0;
1714 int push_items = 0;
1715 struct btrfs_item *item;
1716 u32 old_left_nritems;
1717 u32 right_nritems;
1718 u32 nr;
1719 int ret = 0;
1720 int wret;
1721 u32 this_item_size;
1722 u32 old_left_item_size;
1723
1724 slot = path->slots[1];
1725 if (slot == 0)
1726 return 1;
1727 if (!path->nodes[1])
1728 return 1;
1729
1730 right_nritems = btrfs_header_nritems(right);
1731 if (right_nritems == 0) {
1732 return 1;
1733 }
1734
1735 left = read_tree_block(root, btrfs_node_blockptr(path->nodes[1],
1736 slot - 1), root->leafsize);
1737 free_space = btrfs_leaf_free_space(root, left);
1738 if (free_space < data_size + sizeof(struct btrfs_item)) {
1739 free_extent_buffer(left);
1740 return 1;
1741 }
1742
1743 /* cow and double check */
1744 ret = btrfs_cow_block(trans, root, left,
1745 path->nodes[1], slot - 1, &left);
1746 if (ret) {
1747 /* we hit -ENOSPC, but it isn't fatal here */
1748 free_extent_buffer(left);
1749 return 1;
1750 }
1751
1752 free_space = btrfs_leaf_free_space(root, left);
1753 if (free_space < data_size + sizeof(struct btrfs_item)) {
1754 free_extent_buffer(left);
1755 return 1;
1756 }
1757
1758 if (empty)
1759 nr = right_nritems;
1760 else
1761 nr = right_nritems - 1;
1762
1763 for (i = 0; i < nr; i++) {
1764 item = btrfs_item_nr(right, i);
1765
1766 if (path->slots[0] == i)
1767 push_space += data_size + sizeof(*item);
1768
1769 this_item_size = btrfs_item_size(right, item);
1770 if (this_item_size + sizeof(*item) + push_space > free_space)
1771 break;
1772
1773 push_items++;
1774 push_space += this_item_size + sizeof(*item);
1775 }
1776
1777 if (push_items == 0) {
1778 free_extent_buffer(left);
1779 return 1;
1780 }
1781 if (!empty && push_items == btrfs_header_nritems(right))
1782 WARN_ON(1);
1783
1784 /* push data from right to left */
1785 copy_extent_buffer(left, right,
1786 btrfs_item_nr_offset(btrfs_header_nritems(left)),
1787 btrfs_item_nr_offset(0),
1788 push_items * sizeof(struct btrfs_item));
1789
1790 push_space = BTRFS_LEAF_DATA_SIZE(root) -
1791 btrfs_item_offset_nr(right, push_items -1);
1792
1793 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
1794 leaf_data_end(root, left) - push_space,
1795 btrfs_leaf_data(right) +
1796 btrfs_item_offset_nr(right, push_items - 1),
1797 push_space);
1798 old_left_nritems = btrfs_header_nritems(left);
1799 BUG_ON(old_left_nritems < 0);
1800
1801 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
1802 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1803 u32 ioff;
1804
1805 item = btrfs_item_nr(left, i);
1806 ioff = btrfs_item_offset(left, item);
1807 btrfs_set_item_offset(left, item,
1808 ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
1809 }
1810 btrfs_set_header_nritems(left, old_left_nritems + push_items);
1811
1812 /* fixup right node */
1813 if (push_items > right_nritems) {
1814 printk("push items %d nr %u\n", push_items, right_nritems);
1815 WARN_ON(1);
1816 }
1817
1818 if (push_items < right_nritems) {
1819 push_space = btrfs_item_offset_nr(right, push_items - 1) -
1820 leaf_data_end(root, right);
1821 memmove_extent_buffer(right, btrfs_leaf_data(right) +
1822 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1823 btrfs_leaf_data(right) +
1824 leaf_data_end(root, right), push_space);
1825
1826 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
1827 btrfs_item_nr_offset(push_items),
1828 (btrfs_header_nritems(right) - push_items) *
1829 sizeof(struct btrfs_item));
1830 }
1831 right_nritems -= push_items;
1832 btrfs_set_header_nritems(right, right_nritems);
1833 push_space = BTRFS_LEAF_DATA_SIZE(root);
1834 for (i = 0; i < right_nritems; i++) {
1835 item = btrfs_item_nr(right, i);
1836 push_space = push_space - btrfs_item_size(right, item);
1837 btrfs_set_item_offset(right, item, push_space);
1838 }
1839
1840 btrfs_mark_buffer_dirty(left);
1841 if (right_nritems)
1842 btrfs_mark_buffer_dirty(right);
1843
1844 btrfs_item_key(right, &disk_key, 0);
1845 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1846 if (wret)
1847 ret = wret;
1848
1849 /* then fixup the leaf pointer in the path */
1850 if (path->slots[0] < push_items) {
1851 path->slots[0] += old_left_nritems;
1852 free_extent_buffer(path->nodes[0]);
1853 path->nodes[0] = left;
1854 path->slots[1] -= 1;
1855 } else {
1856 free_extent_buffer(left);
1857 path->slots[0] -= push_items;
1858 }
1859 BUG_ON(path->slots[0] < 0);
1860 return ret;
1861 }
1862
1863 /*
1864 * split the path's leaf in two, making sure there is at least data_size
1865 * available for the resulting leaf level of the path.
1866 *
1867 * returns 0 if all went well and < 0 on failure.
1868 */
1869 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1870 *root, struct btrfs_key *ins_key,
1871 struct btrfs_path *path, int data_size, int extend)
1872 {
1873 u64 root_gen;
1874 struct extent_buffer *l;
1875 u32 nritems;
1876 int mid;
1877 int slot;
1878 struct extent_buffer *right;
1879 int space_needed = data_size + sizeof(struct btrfs_item);
1880 int data_copy_size;
1881 int rt_data_off;
1882 int i;
1883 int ret = 0;
1884 int wret;
1885 int double_split;
1886 int num_doubles = 0;
1887 struct btrfs_disk_key disk_key;
1888
1889 if (extend)
1890 space_needed = data_size;
1891
1892 if (root->ref_cows)
1893 root_gen = trans->transid;
1894 else
1895 root_gen = 0;
1896
1897 /* first try to make some room by pushing left and right */
1898 if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
1899 wret = push_leaf_right(trans, root, path, data_size, 0);
1900 if (wret < 0) {
1901 return wret;
1902 }
1903 if (wret) {
1904 wret = push_leaf_left(trans, root, path, data_size, 0);
1905 if (wret < 0)
1906 return wret;
1907 }
1908 l = path->nodes[0];
1909
1910 /* did the pushes work? */
1911 if (btrfs_leaf_free_space(root, l) >= space_needed)
1912 return 0;
1913 }
1914
1915 if (!path->nodes[1]) {
1916 ret = insert_new_root(trans, root, path, 1);
1917 if (ret)
1918 return ret;
1919 }
1920 again:
1921 double_split = 0;
1922 l = path->nodes[0];
1923 slot = path->slots[0];
1924 nritems = btrfs_header_nritems(l);
1925 mid = (nritems + 1)/ 2;
1926
1927 btrfs_item_key(l, &disk_key, 0);
1928
1929 right = __btrfs_alloc_free_block(trans, root, root->leafsize,
1930 root->root_key.objectid,
1931 root_gen, disk_key.objectid, 0,
1932 l->start, 0);
1933 if (IS_ERR(right))
1934 return PTR_ERR(right);
1935
1936 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
1937 btrfs_set_header_bytenr(right, right->start);
1938 btrfs_set_header_generation(right, trans->transid);
1939 btrfs_set_header_owner(right, root->root_key.objectid);
1940 btrfs_set_header_level(right, 0);
1941 write_extent_buffer(right, root->fs_info->fsid,
1942 (unsigned long)btrfs_header_fsid(right),
1943 BTRFS_FSID_SIZE);
1944 if (mid <= slot) {
1945 if (nritems == 1 ||
1946 leaf_space_used(l, mid, nritems - mid) + space_needed >
1947 BTRFS_LEAF_DATA_SIZE(root)) {
1948 if (slot >= nritems) {
1949 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1950 btrfs_set_header_nritems(right, 0);
1951 wret = insert_ptr(trans, root, path,
1952 &disk_key, right->start,
1953 path->slots[1] + 1, 1);
1954 if (wret)
1955 ret = wret;
1956 free_extent_buffer(path->nodes[0]);
1957 path->nodes[0] = right;
1958 path->slots[0] = 0;
1959 path->slots[1] += 1;
1960 return ret;
1961 }
1962 mid = slot;
1963 if (mid != nritems &&
1964 leaf_space_used(l, mid, nritems - mid) +
1965 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
1966 double_split = 1;
1967 }
1968 }
1969 } else {
1970 if (leaf_space_used(l, 0, mid + 1) + space_needed >
1971 BTRFS_LEAF_DATA_SIZE(root)) {
1972 if (!extend && slot == 0) {
1973 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1974 btrfs_set_header_nritems(right, 0);
1975 wret = insert_ptr(trans, root, path,
1976 &disk_key,
1977 right->start,
1978 path->slots[1], 1);
1979 if (wret)
1980 ret = wret;
1981 free_extent_buffer(path->nodes[0]);
1982 path->nodes[0] = right;
1983 path->slots[0] = 0;
1984 if (path->slots[1] == 0) {
1985 wret = fixup_low_keys(trans, root,
1986 path, &disk_key, 1);
1987 if (wret)
1988 ret = wret;
1989 }
1990 return ret;
1991 } else if (extend && slot == 0) {
1992 mid = 1;
1993 } else {
1994 mid = slot;
1995 if (mid != nritems &&
1996 leaf_space_used(l, mid, nritems - mid) +
1997 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
1998 double_split = 1;
1999 }
2000 }
2001 }
2002 }
2003 nritems = nritems - mid;
2004 btrfs_set_header_nritems(right, nritems);
2005 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
2006
2007 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
2008 btrfs_item_nr_offset(mid),
2009 nritems * sizeof(struct btrfs_item));
2010
2011 copy_extent_buffer(right, l,
2012 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
2013 data_copy_size, btrfs_leaf_data(l) +
2014 leaf_data_end(root, l), data_copy_size);
2015
2016 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
2017 btrfs_item_end_nr(l, mid);
2018
2019 for (i = 0; i < nritems; i++) {
2020 struct btrfs_item *item = btrfs_item_nr(right, i);
2021 u32 ioff = btrfs_item_offset(right, item);
2022 btrfs_set_item_offset(right, item, ioff + rt_data_off);
2023 }
2024
2025 btrfs_set_header_nritems(l, mid);
2026 ret = 0;
2027 btrfs_item_key(right, &disk_key, 0);
2028 wret = insert_ptr(trans, root, path, &disk_key, right->start,
2029 path->slots[1] + 1, 1);
2030 if (wret)
2031 ret = wret;
2032
2033 btrfs_mark_buffer_dirty(right);
2034 btrfs_mark_buffer_dirty(l);
2035 BUG_ON(path->slots[0] != slot);
2036
2037 if (mid <= slot) {
2038 free_extent_buffer(path->nodes[0]);
2039 path->nodes[0] = right;
2040 path->slots[0] -= mid;
2041 path->slots[1] += 1;
2042 } else
2043 free_extent_buffer(right);
2044
2045 BUG_ON(path->slots[0] < 0);
2046
2047 if (double_split) {
2048 BUG_ON(num_doubles != 0);
2049 num_doubles++;
2050 goto again;
2051 }
2052 return ret;
2053 }
2054
2055 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
2056 struct btrfs_root *root,
2057 struct btrfs_path *path,
2058 u32 new_size, int from_end)
2059 {
2060 int ret = 0;
2061 int slot;
2062 int slot_orig;
2063 struct extent_buffer *leaf;
2064 struct btrfs_item *item;
2065 u32 nritems;
2066 unsigned int data_end;
2067 unsigned int old_data_start;
2068 unsigned int old_size;
2069 unsigned int size_diff;
2070 int i;
2071
2072 slot_orig = path->slots[0];
2073 leaf = path->nodes[0];
2074 slot = path->slots[0];
2075
2076 old_size = btrfs_item_size_nr(leaf, slot);
2077 if (old_size == new_size)
2078 return 0;
2079
2080 nritems = btrfs_header_nritems(leaf);
2081 data_end = leaf_data_end(root, leaf);
2082
2083 old_data_start = btrfs_item_offset_nr(leaf, slot);
2084
2085 size_diff = old_size - new_size;
2086
2087 BUG_ON(slot < 0);
2088 BUG_ON(slot >= nritems);
2089
2090 /*
2091 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2092 */
2093 /* first correct the data pointers */
2094 for (i = slot; i < nritems; i++) {
2095 u32 ioff;
2096 item = btrfs_item_nr(leaf, i);
2097 ioff = btrfs_item_offset(leaf, item);
2098 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2099 }
2100
2101 /* shift the data */
2102 if (from_end) {
2103 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2104 data_end + size_diff, btrfs_leaf_data(leaf) +
2105 data_end, old_data_start + new_size - data_end);
2106 } else {
2107 struct btrfs_disk_key disk_key;
2108 u64 offset;
2109
2110 btrfs_item_key(leaf, &disk_key, slot);
2111
2112 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2113 unsigned long ptr;
2114 struct btrfs_file_extent_item *fi;
2115
2116 fi = btrfs_item_ptr(leaf, slot,
2117 struct btrfs_file_extent_item);
2118 fi = (struct btrfs_file_extent_item *)(
2119 (unsigned long)fi - size_diff);
2120
2121 if (btrfs_file_extent_type(leaf, fi) ==
2122 BTRFS_FILE_EXTENT_INLINE) {
2123 ptr = btrfs_item_ptr_offset(leaf, slot);
2124 memmove_extent_buffer(leaf, ptr,
2125 (unsigned long)fi,
2126 offsetof(struct btrfs_file_extent_item,
2127 disk_bytenr));
2128 }
2129 }
2130
2131 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2132 data_end + size_diff, btrfs_leaf_data(leaf) +
2133 data_end, old_data_start - data_end);
2134
2135 offset = btrfs_disk_key_offset(&disk_key);
2136 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2137 btrfs_set_item_key(leaf, &disk_key, slot);
2138 if (slot == 0)
2139 fixup_low_keys(trans, root, path, &disk_key, 1);
2140 }
2141
2142 item = btrfs_item_nr(leaf, slot);
2143 btrfs_set_item_size(leaf, item, new_size);
2144 btrfs_mark_buffer_dirty(leaf);
2145
2146 ret = 0;
2147 if (btrfs_leaf_free_space(root, leaf) < 0) {
2148 btrfs_print_leaf(root, leaf);
2149 BUG();
2150 }
2151 return ret;
2152 }
2153
2154 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2155 struct btrfs_root *root, struct btrfs_path *path,
2156 u32 data_size)
2157 {
2158 int ret = 0;
2159 int slot;
2160 int slot_orig;
2161 struct extent_buffer *leaf;
2162 struct btrfs_item *item;
2163 u32 nritems;
2164 unsigned int data_end;
2165 unsigned int old_data;
2166 unsigned int old_size;
2167 int i;
2168
2169 slot_orig = path->slots[0];
2170 leaf = path->nodes[0];
2171
2172 nritems = btrfs_header_nritems(leaf);
2173 data_end = leaf_data_end(root, leaf);
2174
2175 if (btrfs_leaf_free_space(root, leaf) < data_size) {
2176 btrfs_print_leaf(root, leaf);
2177 BUG();
2178 }
2179 slot = path->slots[0];
2180 old_data = btrfs_item_end_nr(leaf, slot);
2181
2182 BUG_ON(slot < 0);
2183 if (slot >= nritems) {
2184 btrfs_print_leaf(root, leaf);
2185 printk("slot %d too large, nritems %d\n", slot, nritems);
2186 BUG_ON(1);
2187 }
2188
2189 /*
2190 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2191 */
2192 /* first correct the data pointers */
2193 for (i = slot; i < nritems; i++) {
2194 u32 ioff;
2195 item = btrfs_item_nr(leaf, i);
2196 ioff = btrfs_item_offset(leaf, item);
2197 btrfs_set_item_offset(leaf, item, ioff - data_size);
2198 }
2199
2200 /* shift the data */
2201 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2202 data_end - data_size, btrfs_leaf_data(leaf) +
2203 data_end, old_data - data_end);
2204
2205 data_end = old_data;
2206 old_size = btrfs_item_size_nr(leaf, slot);
2207 item = btrfs_item_nr(leaf, slot);
2208 btrfs_set_item_size(leaf, item, old_size + data_size);
2209 btrfs_mark_buffer_dirty(leaf);
2210
2211 ret = 0;
2212 if (btrfs_leaf_free_space(root, leaf) < 0) {
2213 btrfs_print_leaf(root, leaf);
2214 BUG();
2215 }
2216 return ret;
2217 }
2218
2219 /*
2220 * Given a key and some data, insert an item into the tree.
2221 * This does all the path init required, making room in the tree if needed.
2222 */
2223 int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
2224 struct btrfs_root *root,
2225 struct btrfs_path *path,
2226 struct btrfs_key *cpu_key, u32 *data_size,
2227 int nr)
2228 {
2229 struct extent_buffer *leaf;
2230 struct btrfs_item *item;
2231 int ret = 0;
2232 int slot;
2233 int slot_orig;
2234 int i;
2235 u32 nritems;
2236 u32 total_size = 0;
2237 u32 total_data = 0;
2238 unsigned int data_end;
2239 struct btrfs_disk_key disk_key;
2240
2241 for (i = 0; i < nr; i++) {
2242 total_data += data_size[i];
2243 }
2244
2245 /* create a root if there isn't one */
2246 if (!root->node)
2247 BUG();
2248
2249 total_size = total_data + (nr - 1) * sizeof(struct btrfs_item);
2250 ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
2251 if (ret == 0) {
2252 return -EEXIST;
2253 }
2254 if (ret < 0)
2255 goto out;
2256
2257 slot_orig = path->slots[0];
2258 leaf = path->nodes[0];
2259
2260 nritems = btrfs_header_nritems(leaf);
2261 data_end = leaf_data_end(root, leaf);
2262
2263 if (btrfs_leaf_free_space(root, leaf) <
2264 sizeof(struct btrfs_item) + total_size) {
2265 btrfs_print_leaf(root, leaf);
2266 printk("not enough freespace need %u have %d\n",
2267 total_size, btrfs_leaf_free_space(root, leaf));
2268 BUG();
2269 }
2270
2271 slot = path->slots[0];
2272 BUG_ON(slot < 0);
2273
2274 if (slot != nritems) {
2275 int i;
2276 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2277
2278 if (old_data < data_end) {
2279 btrfs_print_leaf(root, leaf);
2280 printk("slot %d old_data %d data_end %d\n",
2281 slot, old_data, data_end);
2282 BUG_ON(1);
2283 }
2284 /*
2285 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2286 */
2287 /* first correct the data pointers */
2288 for (i = slot; i < nritems; i++) {
2289 u32 ioff;
2290
2291 item = btrfs_item_nr(leaf, i);
2292 ioff = btrfs_item_offset(leaf, item);
2293 btrfs_set_item_offset(leaf, item, ioff - total_data);
2294 }
2295
2296 /* shift the items */
2297 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
2298 btrfs_item_nr_offset(slot),
2299 (nritems - slot) * sizeof(struct btrfs_item));
2300
2301 /* shift the data */
2302 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2303 data_end - total_data, btrfs_leaf_data(leaf) +
2304 data_end, old_data - data_end);
2305 data_end = old_data;
2306 }
2307
2308 /* setup the item for the new data */
2309 for (i = 0; i < nr; i++) {
2310 btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
2311 btrfs_set_item_key(leaf, &disk_key, slot + i);
2312 item = btrfs_item_nr(leaf, slot + i);
2313 btrfs_set_item_offset(leaf, item, data_end - data_size[i]);
2314 data_end -= data_size[i];
2315 btrfs_set_item_size(leaf, item, data_size[i]);
2316 }
2317 btrfs_set_header_nritems(leaf, nritems + nr);
2318 btrfs_mark_buffer_dirty(leaf);
2319
2320 ret = 0;
2321 if (slot == 0) {
2322 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2323 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2324 }
2325
2326 if (btrfs_leaf_free_space(root, leaf) < 0) {
2327 btrfs_print_leaf(root, leaf);
2328 BUG();
2329 }
2330
2331 out:
2332 return ret;
2333 }
2334
2335 /*
2336 * Given a key and some data, insert an item into the tree.
2337 * This does all the path init required, making room in the tree if needed.
2338 */
2339 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2340 *root, struct btrfs_key *cpu_key, void *data, u32
2341 data_size)
2342 {
2343 int ret = 0;
2344 struct btrfs_path *path;
2345 struct extent_buffer *leaf;
2346 unsigned long ptr;
2347
2348 path = btrfs_alloc_path();
2349 BUG_ON(!path);
2350 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2351 if (!ret) {
2352 leaf = path->nodes[0];
2353 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2354 write_extent_buffer(leaf, data, ptr, data_size);
2355 btrfs_mark_buffer_dirty(leaf);
2356 }
2357 btrfs_free_path(path);
2358 return ret;
2359 }
2360
2361 /*
2362 * delete the pointer from a given node.
2363 *
2364 * If the delete empties a node, the node is removed from the tree,
2365 * continuing all the way the root if required. The root is converted into
2366 * a leaf if all the nodes are emptied.
2367 */
2368 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2369 struct btrfs_path *path, int level, int slot)
2370 {
2371 struct extent_buffer *parent = path->nodes[level];
2372 u32 nritems;
2373 int ret = 0;
2374 int wret;
2375
2376 nritems = btrfs_header_nritems(parent);
2377 if (slot != nritems -1) {
2378 memmove_extent_buffer(parent,
2379 btrfs_node_key_ptr_offset(slot),
2380 btrfs_node_key_ptr_offset(slot + 1),
2381 sizeof(struct btrfs_key_ptr) *
2382 (nritems - slot - 1));
2383 }
2384 nritems--;
2385 btrfs_set_header_nritems(parent, nritems);
2386 if (nritems == 0 && parent == root->node) {
2387 BUG_ON(btrfs_header_level(root->node) != 1);
2388 /* just turn the root into a leaf and break */
2389 btrfs_set_header_level(root->node, 0);
2390 } else if (slot == 0) {
2391 struct btrfs_disk_key disk_key;
2392
2393 btrfs_node_key(parent, &disk_key, 0);
2394 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2395 if (wret)
2396 ret = wret;
2397 }
2398 btrfs_mark_buffer_dirty(parent);
2399 return ret;
2400 }
2401
2402 /*
2403 * delete the item at the leaf level in path. If that empties
2404 * the leaf, remove it from the tree
2405 */
2406 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2407 struct btrfs_path *path, int slot, int nr)
2408 {
2409 struct extent_buffer *leaf;
2410 struct btrfs_item *item;
2411 int last_off;
2412 int dsize = 0;
2413 int ret = 0;
2414 int wret;
2415 int i;
2416 u32 nritems;
2417
2418 leaf = path->nodes[0];
2419 last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
2420
2421 for (i = 0; i < nr; i++)
2422 dsize += btrfs_item_size_nr(leaf, slot + i);
2423
2424 nritems = btrfs_header_nritems(leaf);
2425
2426 if (slot + nr != nritems) {
2427 int i;
2428 int data_end = leaf_data_end(root, leaf);
2429
2430 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2431 data_end + dsize,
2432 btrfs_leaf_data(leaf) + data_end,
2433 last_off - data_end);
2434
2435 for (i = slot + nr; i < nritems; i++) {
2436 u32 ioff;
2437
2438 item = btrfs_item_nr(leaf, i);
2439 ioff = btrfs_item_offset(leaf, item);
2440 btrfs_set_item_offset(leaf, item, ioff + dsize);
2441 }
2442
2443 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2444 btrfs_item_nr_offset(slot + nr),
2445 sizeof(struct btrfs_item) *
2446 (nritems - slot - nr));
2447 }
2448 btrfs_set_header_nritems(leaf, nritems - nr);
2449 nritems -= nr;
2450
2451 /* delete the leaf if we've emptied it */
2452 if (nritems == 0) {
2453 if (leaf == root->node) {
2454 btrfs_set_header_level(leaf, 0);
2455 } else {
2456 u64 root_gen = btrfs_header_generation(path->nodes[1]);
2457 clean_tree_block(trans, root, leaf);
2458 wait_on_tree_block_writeback(root, leaf);
2459 wret = del_ptr(trans, root, path, 1, path->slots[1]);
2460 if (wret)
2461 ret = wret;
2462 wret = btrfs_free_extent(trans, root,
2463 leaf->start, leaf->len,
2464 btrfs_header_owner(path->nodes[1]),
2465 root_gen, 0, 0, 1);
2466 if (wret)
2467 ret = wret;
2468 }
2469 } else {
2470 int used = leaf_space_used(leaf, 0, nritems);
2471 if (slot == 0) {
2472 struct btrfs_disk_key disk_key;
2473
2474 btrfs_item_key(leaf, &disk_key, 0);
2475 wret = fixup_low_keys(trans, root, path,
2476 &disk_key, 1);
2477 if (wret)
2478 ret = wret;
2479 }
2480
2481 /* delete the leaf if it is mostly empty */
2482 if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
2483 /* push_leaf_left fixes the path.
2484 * make sure the path still points to our leaf
2485 * for possible call to del_ptr below
2486 */
2487 slot = path->slots[1];
2488 extent_buffer_get(leaf);
2489
2490 wret = push_leaf_left(trans, root, path, 1, 1);
2491 if (wret < 0 && wret != -ENOSPC)
2492 ret = wret;
2493
2494 if (path->nodes[0] == leaf &&
2495 btrfs_header_nritems(leaf)) {
2496 wret = push_leaf_right(trans, root, path, 1, 1);
2497 if (wret < 0 && wret != -ENOSPC)
2498 ret = wret;
2499 }
2500
2501 if (btrfs_header_nritems(leaf) == 0) {
2502 u64 root_gen;
2503 u64 bytenr = leaf->start;
2504 u32 blocksize = leaf->len;
2505
2506 root_gen = btrfs_header_generation(
2507 path->nodes[1]);
2508
2509 clean_tree_block(trans, root, leaf);
2510 wait_on_tree_block_writeback(root, leaf);
2511
2512 wret = del_ptr(trans, root, path, 1, slot);
2513 if (wret)
2514 ret = wret;
2515
2516 free_extent_buffer(leaf);
2517 wret = btrfs_free_extent(trans, root, bytenr,
2518 blocksize,
2519 btrfs_header_owner(path->nodes[1]),
2520 root_gen, 0, 0, 1);
2521 if (wret)
2522 ret = wret;
2523 } else {
2524 btrfs_mark_buffer_dirty(leaf);
2525 free_extent_buffer(leaf);
2526 }
2527 } else {
2528 btrfs_mark_buffer_dirty(leaf);
2529 }
2530 }
2531 return ret;
2532 }
2533
2534 /*
2535 * walk up the tree as far as required to find the previous leaf.
2536 * returns 0 if it found something or 1 if there are no lesser leaves.
2537 * returns < 0 on io errors.
2538 */
2539 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
2540 {
2541 u64 bytenr;
2542 int slot;
2543 int level = 1;
2544 struct extent_buffer *c;
2545 struct extent_buffer *next = NULL;
2546
2547 while(level < BTRFS_MAX_LEVEL) {
2548 if (!path->nodes[level])
2549 return 1;
2550
2551 slot = path->slots[level];
2552 c = path->nodes[level];
2553 if (slot == 0) {
2554 level++;
2555 if (level == BTRFS_MAX_LEVEL)
2556 return 1;
2557 continue;
2558 }
2559 slot--;
2560
2561 bytenr = btrfs_node_blockptr(c, slot);
2562 if (next)
2563 free_extent_buffer(next);
2564
2565 next = read_tree_block(root, bytenr,
2566 btrfs_level_size(root, level - 1));
2567 break;
2568 }
2569 path->slots[level] = slot;
2570 while(1) {
2571 level--;
2572 c = path->nodes[level];
2573 free_extent_buffer(c);
2574 slot = btrfs_header_nritems(next);
2575 if (slot != 0)
2576 slot--;
2577 path->nodes[level] = next;
2578 path->slots[level] = slot;
2579 if (!level)
2580 break;
2581 next = read_tree_block(root, btrfs_node_blockptr(next, slot),
2582 btrfs_level_size(root, level - 1));
2583 }
2584 return 0;
2585 }
2586
2587 /*
2588 * walk up the tree as far as required to find the next leaf.
2589 * returns 0 if it found something or 1 if there are no greater leaves.
2590 * returns < 0 on io errors.
2591 */
2592 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2593 {
2594 int slot;
2595 int level = 1;
2596 u64 bytenr;
2597 struct extent_buffer *c;
2598 struct extent_buffer *next = NULL;
2599
2600 while(level < BTRFS_MAX_LEVEL) {
2601 if (!path->nodes[level])
2602 return 1;
2603
2604 slot = path->slots[level] + 1;
2605 c = path->nodes[level];
2606 if (slot >= btrfs_header_nritems(c)) {
2607 level++;
2608 if (level == BTRFS_MAX_LEVEL)
2609 return 1;
2610 continue;
2611 }
2612
2613 bytenr = btrfs_node_blockptr(c, slot);
2614 if (next)
2615 free_extent_buffer(next);
2616
2617 if (path->reada)
2618 reada_for_search(root, path, level, slot, 0);
2619
2620 next = read_tree_block(root, bytenr,
2621 btrfs_level_size(root, level -1));
2622 break;
2623 }
2624 path->slots[level] = slot;
2625 while(1) {
2626 level--;
2627 c = path->nodes[level];
2628 free_extent_buffer(c);
2629 path->nodes[level] = next;
2630 path->slots[level] = 0;
2631 if (!level)
2632 break;
2633 if (path->reada)
2634 reada_for_search(root, path, level, 0, 0);
2635 next = read_tree_block(root, btrfs_node_blockptr(next, 0),
2636 btrfs_level_size(root, level - 1));
2637 }
2638 return 0;
2639 }
2640
2641 int btrfs_previous_item(struct btrfs_root *root,
2642 struct btrfs_path *path, u64 min_objectid,
2643 int type)
2644 {
2645 struct btrfs_key found_key;
2646 struct extent_buffer *leaf;
2647 int ret;
2648
2649 while(1) {
2650 if (path->slots[0] == 0) {
2651 ret = btrfs_prev_leaf(root, path);
2652 if (ret != 0)
2653 return ret;
2654 } else {
2655 path->slots[0]--;
2656 }
2657 leaf = path->nodes[0];
2658 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2659 if (found_key.type == type)
2660 return 0;
2661 }
2662 return 1;
2663 }
2664
Btrfs-progs-unstable mirror