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