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Btrfs: Large block related defrag optimizations
[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 btrfs_set_buffer_defrag_done(tmp);
284 free_extent_buffer(tmp);
285 }
286 return err;
287 }
288
289 /*
290 * The leaf data grows from end-to-front in the node.
291 * this returns the address of the start of the last item,
292 * which is the stop of the leaf data stack
293 */
294 static inline unsigned int leaf_data_end(struct btrfs_root *root,
295 struct extent_buffer *leaf)
296 {
297 u32 nr = btrfs_header_nritems(leaf);
298 if (nr == 0)
299 return BTRFS_LEAF_DATA_SIZE(root);
300 return btrfs_item_offset_nr(leaf, nr - 1);
301 }
302
303 /*
304 * compare two keys in a memcmp fashion
305 */
306 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
307 {
308 struct btrfs_key k1;
309
310 btrfs_disk_key_to_cpu(&k1, disk);
311
312 if (k1.objectid > k2->objectid)
313 return 1;
314 if (k1.objectid < k2->objectid)
315 return -1;
316 if (k1.type > k2->type)
317 return 1;
318 if (k1.type < k2->type)
319 return -1;
320 if (k1.offset > k2->offset)
321 return 1;
322 if (k1.offset < k2->offset)
323 return -1;
324 return 0;
325 }
326
327 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
328 int level)
329 {
330 struct extent_buffer *parent = NULL;
331 struct extent_buffer *node = path->nodes[level];
332 struct btrfs_disk_key parent_key;
333 struct btrfs_disk_key node_key;
334 int parent_slot;
335 int slot;
336 struct btrfs_key cpukey;
337 u32 nritems = btrfs_header_nritems(node);
338
339 if (path->nodes[level + 1])
340 parent = path->nodes[level + 1];
341
342 slot = path->slots[level];
343 BUG_ON(nritems == 0);
344 if (parent) {
345 parent_slot = path->slots[level + 1];
346 btrfs_node_key(parent, &parent_key, parent_slot);
347 btrfs_node_key(node, &node_key, 0);
348 BUG_ON(memcmp(&parent_key, &node_key,
349 sizeof(struct btrfs_disk_key)));
350 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
351 btrfs_header_bytenr(node));
352 }
353 BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
354 if (slot != 0) {
355 btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
356 btrfs_node_key(node, &node_key, slot);
357 BUG_ON(comp_keys(&node_key, &cpukey) <= 0);
358 }
359 if (slot < nritems - 1) {
360 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
361 btrfs_node_key(node, &node_key, slot);
362 BUG_ON(comp_keys(&node_key, &cpukey) >= 0);
363 }
364 return 0;
365 }
366
367 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
368 int level)
369 {
370 struct extent_buffer *leaf = path->nodes[level];
371 struct extent_buffer *parent = NULL;
372 int parent_slot;
373 struct btrfs_key cpukey;
374 struct btrfs_disk_key parent_key;
375 struct btrfs_disk_key leaf_key;
376 int slot = path->slots[0];
377
378 u32 nritems = btrfs_header_nritems(leaf);
379
380 if (path->nodes[level + 1])
381 parent = path->nodes[level + 1];
382
383 if (nritems == 0)
384 return 0;
385
386 if (parent) {
387 parent_slot = path->slots[level + 1];
388 btrfs_node_key(parent, &parent_key, parent_slot);
389 btrfs_item_key(leaf, &leaf_key, 0);
390
391 BUG_ON(memcmp(&parent_key, &leaf_key,
392 sizeof(struct btrfs_disk_key)));
393 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
394 btrfs_header_bytenr(leaf));
395 }
396 #if 0
397 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
398 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
399 btrfs_item_key(leaf, &leaf_key, i);
400 if (comp_keys(&leaf_key, &cpukey) >= 0) {
401 btrfs_print_leaf(root, leaf);
402 printk("slot %d offset bad key\n", i);
403 BUG_ON(1);
404 }
405 if (btrfs_item_offset_nr(leaf, i) !=
406 btrfs_item_end_nr(leaf, i + 1)) {
407 btrfs_print_leaf(root, leaf);
408 printk("slot %d offset bad\n", i);
409 BUG_ON(1);
410 }
411 if (i == 0) {
412 if (btrfs_item_offset_nr(leaf, i) +
413 btrfs_item_size_nr(leaf, i) !=
414 BTRFS_LEAF_DATA_SIZE(root)) {
415 btrfs_print_leaf(root, leaf);
416 printk("slot %d first offset bad\n", i);
417 BUG_ON(1);
418 }
419 }
420 }
421 if (nritems > 0) {
422 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
423 btrfs_print_leaf(root, leaf);
424 printk("slot %d bad size \n", nritems - 1);
425 BUG_ON(1);
426 }
427 }
428 #endif
429 if (slot != 0 && slot < nritems - 1) {
430 btrfs_item_key(leaf, &leaf_key, slot);
431 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
432 if (comp_keys(&leaf_key, &cpukey) <= 0) {
433 btrfs_print_leaf(root, leaf);
434 printk("slot %d offset bad key\n", slot);
435 BUG_ON(1);
436 }
437 if (btrfs_item_offset_nr(leaf, slot - 1) !=
438 btrfs_item_end_nr(leaf, slot)) {
439 btrfs_print_leaf(root, leaf);
440 printk("slot %d offset bad\n", slot);
441 BUG_ON(1);
442 }
443 }
444 if (slot < nritems - 1) {
445 btrfs_item_key(leaf, &leaf_key, slot);
446 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
447 BUG_ON(comp_keys(&leaf_key, &cpukey) >= 0);
448 if (btrfs_item_offset_nr(leaf, slot) !=
449 btrfs_item_end_nr(leaf, slot + 1)) {
450 btrfs_print_leaf(root, leaf);
451 printk("slot %d offset bad\n", slot);
452 BUG_ON(1);
453 }
454 }
455 BUG_ON(btrfs_item_offset_nr(leaf, 0) +
456 btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
457 return 0;
458 }
459
460 static int check_block(struct btrfs_root *root, struct btrfs_path *path,
461 int level)
462 {
463 return 0;
464 #if 0
465 struct extent_buffer *buf = path->nodes[level];
466
467 if (memcmp_extent_buffer(buf, root->fs_info->fsid,
468 (unsigned long)btrfs_header_fsid(buf),
469 BTRFS_FSID_SIZE)) {
470 printk("warning bad block %Lu\n", buf->start);
471 return 1;
472 }
473 #endif
474 if (level == 0)
475 return check_leaf(root, path, level);
476 return check_node(root, path, level);
477 }
478
479 /*
480 * search for key in the extent_buffer. The items start at offset p,
481 * and they are item_size apart. There are 'max' items in p.
482 *
483 * the slot in the array is returned via slot, and it points to
484 * the place where you would insert key if it is not found in
485 * the array.
486 *
487 * slot may point to max if the key is bigger than all of the keys
488 */
489 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
490 int item_size, struct btrfs_key *key,
491 int max, int *slot)
492 {
493 int low = 0;
494 int high = max;
495 int mid;
496 int ret;
497 struct btrfs_disk_key *tmp = NULL;
498 struct btrfs_disk_key unaligned;
499 unsigned long offset;
500 char *map_token = NULL;
501 char *kaddr = NULL;
502 unsigned long map_start = 0;
503 unsigned long map_len = 0;
504 int err;
505
506 while(low < high) {
507 mid = (low + high) / 2;
508 offset = p + mid * item_size;
509
510 if (!map_token || offset < map_start ||
511 (offset + sizeof(struct btrfs_disk_key)) >
512 map_start + map_len) {
513 if (map_token) {
514 unmap_extent_buffer(eb, map_token, KM_USER0);
515 map_token = NULL;
516 }
517 err = map_extent_buffer(eb, offset,
518 sizeof(struct btrfs_disk_key),
519 &map_token, &kaddr,
520 &map_start, &map_len, KM_USER0);
521
522 if (!err) {
523 tmp = (struct btrfs_disk_key *)(kaddr + offset -
524 map_start);
525 } else {
526 read_extent_buffer(eb, &unaligned,
527 offset, sizeof(unaligned));
528 tmp = &unaligned;
529 }
530
531 } else {
532 tmp = (struct btrfs_disk_key *)(kaddr + offset -
533 map_start);
534 }
535 ret = comp_keys(tmp, key);
536
537 if (ret < 0)
538 low = mid + 1;
539 else if (ret > 0)
540 high = mid;
541 else {
542 *slot = mid;
543 if (map_token)
544 unmap_extent_buffer(eb, map_token, KM_USER0);
545 return 0;
546 }
547 }
548 *slot = low;
549 if (map_token)
550 unmap_extent_buffer(eb, map_token, KM_USER0);
551 return 1;
552 }
553
554 /*
555 * simple bin_search frontend that does the right thing for
556 * leaves vs nodes
557 */
558 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
559 int level, int *slot)
560 {
561 if (level == 0) {
562 return generic_bin_search(eb,
563 offsetof(struct btrfs_leaf, items),
564 sizeof(struct btrfs_item),
565 key, btrfs_header_nritems(eb),
566 slot);
567 } else {
568 return generic_bin_search(eb,
569 offsetof(struct btrfs_node, ptrs),
570 sizeof(struct btrfs_key_ptr),
571 key, btrfs_header_nritems(eb),
572 slot);
573 }
574 return -1;
575 }
576
577 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
578 struct extent_buffer *parent, int slot)
579 {
580 if (slot < 0)
581 return NULL;
582 if (slot >= btrfs_header_nritems(parent))
583 return NULL;
584 return read_tree_block(root, btrfs_node_blockptr(parent, slot),
585 btrfs_level_size(root, btrfs_header_level(parent) - 1));
586 }
587
588 static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
589 *root, struct btrfs_path *path, int level)
590 {
591 struct extent_buffer *right = NULL;
592 struct extent_buffer *mid;
593 struct extent_buffer *left = NULL;
594 struct extent_buffer *parent = NULL;
595 int ret = 0;
596 int wret;
597 int pslot;
598 int orig_slot = path->slots[level];
599 int err_on_enospc = 0;
600 u64 orig_ptr;
601
602 if (level == 0)
603 return 0;
604
605 mid = path->nodes[level];
606 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
607
608 if (level < BTRFS_MAX_LEVEL - 1)
609 parent = path->nodes[level + 1];
610 pslot = path->slots[level + 1];
611
612 /*
613 * deal with the case where there is only one pointer in the root
614 * by promoting the node below to a root
615 */
616 if (!parent) {
617 struct extent_buffer *child;
618
619 if (btrfs_header_nritems(mid) != 1)
620 return 0;
621
622 /* promote the child to a root */
623 child = read_node_slot(root, mid, 0);
624 BUG_ON(!child);
625 root->node = child;
626 path->nodes[level] = NULL;
627 clean_tree_block(trans, root, mid);
628 wait_on_tree_block_writeback(root, mid);
629 /* once for the path */
630 free_extent_buffer(mid);
631 ret = btrfs_free_extent(trans, root, mid->start, mid->len, 1);
632 /* once for the root ptr */
633 free_extent_buffer(mid);
634 return ret;
635 }
636 if (btrfs_header_nritems(mid) >
637 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
638 return 0;
639
640 if (btrfs_header_nritems(mid) < 2)
641 err_on_enospc = 1;
642
643 left = read_node_slot(root, parent, pslot - 1);
644 if (left) {
645 wret = btrfs_cow_block(trans, root, left,
646 parent, pslot - 1, &left);
647 if (wret) {
648 ret = wret;
649 goto enospc;
650 }
651 }
652 right = read_node_slot(root, parent, pslot + 1);
653 if (right) {
654 wret = btrfs_cow_block(trans, root, right,
655 parent, pslot + 1, &right);
656 if (wret) {
657 ret = wret;
658 goto enospc;
659 }
660 }
661
662 /* first, try to make some room in the middle buffer */
663 if (left) {
664 orig_slot += btrfs_header_nritems(left);
665 wret = push_node_left(trans, root, left, mid);
666 if (wret < 0)
667 ret = wret;
668 if (btrfs_header_nritems(mid) < 2)
669 err_on_enospc = 1;
670 }
671
672 /*
673 * then try to empty the right most buffer into the middle
674 */
675 if (right) {
676 wret = push_node_left(trans, root, mid, right);
677 if (wret < 0 && wret != -ENOSPC)
678 ret = wret;
679 if (btrfs_header_nritems(right) == 0) {
680 u64 bytenr = right->start;
681 u32 blocksize = right->len;
682
683 clean_tree_block(trans, root, right);
684 wait_on_tree_block_writeback(root, right);
685 free_extent_buffer(right);
686 right = NULL;
687 wret = del_ptr(trans, root, path, level + 1, pslot +
688 1);
689 if (wret)
690 ret = wret;
691 wret = btrfs_free_extent(trans, root, bytenr,
692 blocksize, 1);
693 if (wret)
694 ret = wret;
695 } else {
696 struct btrfs_disk_key right_key;
697 btrfs_node_key(right, &right_key, 0);
698 btrfs_set_node_key(parent, &right_key, pslot + 1);
699 btrfs_mark_buffer_dirty(parent);
700 }
701 }
702 if (btrfs_header_nritems(mid) == 1) {
703 /*
704 * we're not allowed to leave a node with one item in the
705 * tree during a delete. A deletion from lower in the tree
706 * could try to delete the only pointer in this node.
707 * So, pull some keys from the left.
708 * There has to be a left pointer at this point because
709 * otherwise we would have pulled some pointers from the
710 * right
711 */
712 BUG_ON(!left);
713 wret = balance_node_right(trans, root, mid, left);
714 if (wret < 0) {
715 ret = wret;
716 goto enospc;
717 }
718 BUG_ON(wret == 1);
719 }
720 if (btrfs_header_nritems(mid) == 0) {
721 /* we've managed to empty the middle node, drop it */
722 u64 bytenr = mid->start;
723 u32 blocksize = mid->len;
724 clean_tree_block(trans, root, mid);
725 wait_on_tree_block_writeback(root, mid);
726 free_extent_buffer(mid);
727 mid = NULL;
728 wret = del_ptr(trans, root, path, level + 1, pslot);
729 if (wret)
730 ret = wret;
731 wret = btrfs_free_extent(trans, root, bytenr, blocksize, 1);
732 if (wret)
733 ret = wret;
734 } else {
735 /* update the parent key to reflect our changes */
736 struct btrfs_disk_key mid_key;
737 btrfs_node_key(mid, &mid_key, 0);
738 btrfs_set_node_key(parent, &mid_key, pslot);
739 btrfs_mark_buffer_dirty(parent);
740 }
741
742 /* update the path */
743 if (left) {
744 if (btrfs_header_nritems(left) > orig_slot) {
745 extent_buffer_get(left);
746 path->nodes[level] = left;
747 path->slots[level + 1] -= 1;
748 path->slots[level] = orig_slot;
749 if (mid)
750 free_extent_buffer(mid);
751 } else {
752 orig_slot -= btrfs_header_nritems(left);
753 path->slots[level] = orig_slot;
754 }
755 }
756 /* double check we haven't messed things up */
757 check_block(root, path, level);
758 if (orig_ptr !=
759 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
760 BUG();
761 enospc:
762 if (right)
763 free_extent_buffer(right);
764 if (left)
765 free_extent_buffer(left);
766 return ret;
767 }
768
769 /* returns zero if the push worked, non-zero otherwise */
770 static int push_nodes_for_insert(struct btrfs_trans_handle *trans,
771 struct btrfs_root *root,
772 struct btrfs_path *path, int level)
773 {
774 struct extent_buffer *right = NULL;
775 struct extent_buffer *mid;
776 struct extent_buffer *left = NULL;
777 struct extent_buffer *parent = NULL;
778 int ret = 0;
779 int wret;
780 int pslot;
781 int orig_slot = path->slots[level];
782 u64 orig_ptr;
783
784 if (level == 0)
785 return 1;
786
787 mid = path->nodes[level];
788 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
789
790 if (level < BTRFS_MAX_LEVEL - 1)
791 parent = path->nodes[level + 1];
792 pslot = path->slots[level + 1];
793
794 if (!parent)
795 return 1;
796
797 left = read_node_slot(root, parent, pslot - 1);
798
799 /* first, try to make some room in the middle buffer */
800 if (left) {
801 u32 left_nr;
802 left_nr = btrfs_header_nritems(left);
803 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
804 wret = 1;
805 } else {
806 ret = btrfs_cow_block(trans, root, left, parent,
807 pslot - 1, &left);
808 if (ret)
809 wret = 1;
810 else {
811 wret = push_node_left(trans, root,
812 left, mid);
813 }
814 }
815 if (wret < 0)
816 ret = wret;
817 if (wret == 0) {
818 struct btrfs_disk_key disk_key;
819 orig_slot += left_nr;
820 btrfs_node_key(mid, &disk_key, 0);
821 btrfs_set_node_key(parent, &disk_key, pslot);
822 btrfs_mark_buffer_dirty(parent);
823 if (btrfs_header_nritems(left) > orig_slot) {
824 path->nodes[level] = left;
825 path->slots[level + 1] -= 1;
826 path->slots[level] = orig_slot;
827 free_extent_buffer(mid);
828 } else {
829 orig_slot -=
830 btrfs_header_nritems(left);
831 path->slots[level] = orig_slot;
832 free_extent_buffer(left);
833 }
834 return 0;
835 }
836 free_extent_buffer(left);
837 }
838 right= read_node_slot(root, parent, pslot + 1);
839
840 /*
841 * then try to empty the right most buffer into the middle
842 */
843 if (right) {
844 u32 right_nr;
845 right_nr = btrfs_header_nritems(right);
846 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
847 wret = 1;
848 } else {
849 ret = btrfs_cow_block(trans, root, right,
850 parent, pslot + 1,
851 &right);
852 if (ret)
853 wret = 1;
854 else {
855 wret = balance_node_right(trans, root,
856 right, mid);
857 }
858 }
859 if (wret < 0)
860 ret = wret;
861 if (wret == 0) {
862 struct btrfs_disk_key disk_key;
863
864 btrfs_node_key(right, &disk_key, 0);
865 btrfs_set_node_key(parent, &disk_key, pslot + 1);
866 btrfs_mark_buffer_dirty(parent);
867
868 if (btrfs_header_nritems(mid) <= orig_slot) {
869 path->nodes[level] = right;
870 path->slots[level + 1] += 1;
871 path->slots[level] = orig_slot -
872 btrfs_header_nritems(mid);
873 free_extent_buffer(mid);
874 } else {
875 free_extent_buffer(right);
876 }
877 return 0;
878 }
879 free_extent_buffer(right);
880 }
881 return 1;
882 }
883
884 /*
885 * readahead one full node of leaves
886 */
887 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
888 int level, int slot)
889 {
890 struct extent_buffer *node;
891 u32 nritems;
892 u64 search;
893 u64 lowest_read;
894 u64 highest_read;
895 u64 nread = 0;
896 int direction = path->reada;
897 struct extent_buffer *eb;
898 u32 nr;
899 u32 blocksize;
900 u32 nscan = 0;
901
902 if (level == 0)
903 return;
904
905 if (!path->nodes[level])
906 return;
907
908 node = path->nodes[level];
909 search = btrfs_node_blockptr(node, slot);
910 blocksize = btrfs_level_size(root, level - 1);
911 eb = btrfs_find_tree_block(root, search, blocksize);
912 if (eb) {
913 free_extent_buffer(eb);
914 return;
915 }
916
917 highest_read = search;
918 lowest_read = search;
919
920 nritems = btrfs_header_nritems(node);
921 nr = slot;
922 while(1) {
923 if (direction < 0) {
924 if (nr == 0)
925 break;
926 nr--;
927 } else if (direction > 0) {
928 nr++;
929 if (nr >= nritems)
930 break;
931 }
932 search = btrfs_node_blockptr(node, nr);
933 if ((search >= lowest_read && search <= highest_read) ||
934 (search < lowest_read && lowest_read - search <= 32768) ||
935 (search > highest_read && search - highest_read <= 32768)) {
936 readahead_tree_block(root, search, blocksize);
937 nread += blocksize;
938 }
939 nscan++;
940 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
941 break;
942 if(nread > (1024 * 1024) || nscan > 128)
943 break;
944
945 if (search < lowest_read)
946 lowest_read = search;
947 if (search > highest_read)
948 highest_read = search;
949 }
950 }
951 /*
952 * look for key in the tree. path is filled in with nodes along the way
953 * if key is found, we return zero and you can find the item in the leaf
954 * level of the path (level 0)
955 *
956 * If the key isn't found, the path points to the slot where it should
957 * be inserted, and 1 is returned. If there are other errors during the
958 * search a negative error number is returned.
959 *
960 * if ins_len > 0, nodes and leaves will be split as we walk down the
961 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
962 * possible)
963 */
964 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
965 *root, struct btrfs_key *key, struct btrfs_path *p, int
966 ins_len, int cow)
967 {
968 struct extent_buffer *b;
969 u64 bytenr;
970 int slot;
971 int ret;
972 int level;
973 int should_reada = p->reada;
974 u8 lowest_level = 0;
975
976 lowest_level = p->lowest_level;
977 WARN_ON(lowest_level && ins_len);
978 WARN_ON(p->nodes[0] != NULL);
979 WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
980 again:
981 b = root->node;
982 extent_buffer_get(b);
983 while (b) {
984 level = btrfs_header_level(b);
985 if (cow) {
986 int wret;
987 wret = btrfs_cow_block(trans, root, b,
988 p->nodes[level + 1],
989 p->slots[level + 1],
990 &b);
991 if (wret) {
992 free_extent_buffer(b);
993 return wret;
994 }
995 }
996 BUG_ON(!cow && ins_len);
997 if (level != btrfs_header_level(b))
998 WARN_ON(1);
999 level = btrfs_header_level(b);
1000 p->nodes[level] = b;
1001 ret = check_block(root, p, level);
1002 if (ret)
1003 return -1;
1004 ret = bin_search(b, key, level, &slot);
1005 if (level != 0) {
1006 if (ret && slot > 0)
1007 slot -= 1;
1008 p->slots[level] = slot;
1009 if (ins_len > 0 && btrfs_header_nritems(b) >=
1010 BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1011 int sret = split_node(trans, root, p, level);
1012 BUG_ON(sret > 0);
1013 if (sret)
1014 return sret;
1015 b = p->nodes[level];
1016 slot = p->slots[level];
1017 } else if (ins_len < 0) {
1018 int sret = balance_level(trans, root, p,
1019 level);
1020 if (sret)
1021 return sret;
1022 b = p->nodes[level];
1023 if (!b) {
1024 btrfs_release_path(NULL, p);
1025 goto again;
1026 }
1027 slot = p->slots[level];
1028 BUG_ON(btrfs_header_nritems(b) == 1);
1029 }
1030 /* this is only true while dropping a snapshot */
1031 if (level == lowest_level)
1032 break;
1033 bytenr = btrfs_node_blockptr(b, slot);
1034 if (should_reada)
1035 reada_for_search(root, p, level, slot);
1036 b = read_tree_block(root, bytenr,
1037 btrfs_level_size(root, level - 1));
1038 } else {
1039 p->slots[level] = slot;
1040 if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1041 sizeof(struct btrfs_item) + ins_len) {
1042 int sret = split_leaf(trans, root, key,
1043 p, ins_len);
1044 BUG_ON(sret > 0);
1045 if (sret)
1046 return sret;
1047 }
1048 return ret;
1049 }
1050 }
1051 return 1;
1052 }
1053
1054 /*
1055 * adjust the pointers going up the tree, starting at level
1056 * making sure the right key of each node is points to 'key'.
1057 * This is used after shifting pointers to the left, so it stops
1058 * fixing up pointers when a given leaf/node is not in slot 0 of the
1059 * higher levels
1060 *
1061 * If this fails to write a tree block, it returns -1, but continues
1062 * fixing up the blocks in ram so the tree is consistent.
1063 */
1064 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1065 struct btrfs_root *root, struct btrfs_path *path,
1066 struct btrfs_disk_key *key, int level)
1067 {
1068 int i;
1069 int ret = 0;
1070 struct extent_buffer *t;
1071
1072 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1073 int tslot = path->slots[i];
1074 if (!path->nodes[i])
1075 break;
1076 t = path->nodes[i];
1077 btrfs_set_node_key(t, key, tslot);
1078 btrfs_mark_buffer_dirty(path->nodes[i]);
1079 if (tslot != 0)
1080 break;
1081 }
1082 return ret;
1083 }
1084
1085 /*
1086 * try to push data from one node into the next node left in the
1087 * tree.
1088 *
1089 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1090 * error, and > 0 if there was no room in the left hand block.
1091 */
1092 static int push_node_left(struct btrfs_trans_handle *trans, struct btrfs_root
1093 *root, struct extent_buffer *dst,
1094 struct extent_buffer *src)
1095 {
1096 int push_items = 0;
1097 int src_nritems;
1098 int dst_nritems;
1099 int ret = 0;
1100
1101 src_nritems = btrfs_header_nritems(src);
1102 dst_nritems = btrfs_header_nritems(dst);
1103 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1104
1105 if (push_items <= 0) {
1106 return 1;
1107 }
1108
1109 if (src_nritems < push_items)
1110 push_items = src_nritems;
1111
1112 copy_extent_buffer(dst, src,
1113 btrfs_node_key_ptr_offset(dst_nritems),
1114 btrfs_node_key_ptr_offset(0),
1115 push_items * sizeof(struct btrfs_key_ptr));
1116
1117 if (push_items < src_nritems) {
1118 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1119 btrfs_node_key_ptr_offset(push_items),
1120 (src_nritems - push_items) *
1121 sizeof(struct btrfs_key_ptr));
1122 }
1123 btrfs_set_header_nritems(src, src_nritems - push_items);
1124 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1125 btrfs_mark_buffer_dirty(src);
1126 btrfs_mark_buffer_dirty(dst);
1127 return ret;
1128 }
1129
1130 /*
1131 * try to push data from one node into the next node right in the
1132 * tree.
1133 *
1134 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1135 * error, and > 0 if there was no room in the right hand block.
1136 *
1137 * this will only push up to 1/2 the contents of the left node over
1138 */
1139 static int balance_node_right(struct btrfs_trans_handle *trans,
1140 struct btrfs_root *root,
1141 struct extent_buffer *dst,
1142 struct extent_buffer *src)
1143 {
1144 int push_items = 0;
1145 int max_push;
1146 int src_nritems;
1147 int dst_nritems;
1148 int ret = 0;
1149
1150 src_nritems = btrfs_header_nritems(src);
1151 dst_nritems = btrfs_header_nritems(dst);
1152 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1153 if (push_items <= 0)
1154 return 1;
1155
1156 max_push = src_nritems / 2 + 1;
1157 /* don't try to empty the node */
1158 if (max_push >= src_nritems)
1159 return 1;
1160
1161 if (max_push < push_items)
1162 push_items = max_push;
1163
1164 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1165 btrfs_node_key_ptr_offset(0),
1166 (dst_nritems) *
1167 sizeof(struct btrfs_key_ptr));
1168
1169 copy_extent_buffer(dst, src,
1170 btrfs_node_key_ptr_offset(0),
1171 btrfs_node_key_ptr_offset(src_nritems - push_items),
1172 push_items * sizeof(struct btrfs_key_ptr));
1173
1174 btrfs_set_header_nritems(src, src_nritems - push_items);
1175 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1176
1177 btrfs_mark_buffer_dirty(src);
1178 btrfs_mark_buffer_dirty(dst);
1179 return ret;
1180 }
1181
1182 /*
1183 * helper function to insert a new root level in the tree.
1184 * A new node is allocated, and a single item is inserted to
1185 * point to the existing root
1186 *
1187 * returns zero on success or < 0 on failure.
1188 */
1189 static int insert_new_root(struct btrfs_trans_handle *trans,
1190 struct btrfs_root *root,
1191 struct btrfs_path *path, int level)
1192 {
1193 struct extent_buffer *lower;
1194 struct extent_buffer *c;
1195 struct btrfs_disk_key lower_key;
1196
1197 BUG_ON(path->nodes[level]);
1198 BUG_ON(path->nodes[level-1] != root->node);
1199
1200 c = btrfs_alloc_free_block(trans, root, root->nodesize,
1201 root->node->start, 0);
1202 if (IS_ERR(c))
1203 return PTR_ERR(c);
1204 memset_extent_buffer(c, 0, 0, root->nodesize);
1205 btrfs_set_header_nritems(c, 1);
1206 btrfs_set_header_level(c, level);
1207 btrfs_set_header_bytenr(c, c->start);
1208 btrfs_set_header_generation(c, trans->transid);
1209 btrfs_set_header_owner(c, root->root_key.objectid);
1210 lower = path->nodes[level-1];
1211
1212 write_extent_buffer(c, root->fs_info->fsid,
1213 (unsigned long)btrfs_header_fsid(c),
1214 BTRFS_FSID_SIZE);
1215 if (level == 1)
1216 btrfs_item_key(lower, &lower_key, 0);
1217 else
1218 btrfs_node_key(lower, &lower_key, 0);
1219 btrfs_set_node_key(c, &lower_key, 0);
1220 btrfs_set_node_blockptr(c, 0, lower->start);
1221
1222 btrfs_mark_buffer_dirty(c);
1223
1224 /* the super has an extra ref to root->node */
1225 free_extent_buffer(root->node);
1226 root->node = c;
1227 extent_buffer_get(c);
1228 path->nodes[level] = c;
1229 path->slots[level] = 0;
1230 return 0;
1231 }
1232
1233 /*
1234 * worker function to insert a single pointer in a node.
1235 * the node should have enough room for the pointer already
1236 *
1237 * slot and level indicate where you want the key to go, and
1238 * blocknr is the block the key points to.
1239 *
1240 * returns zero on success and < 0 on any error
1241 */
1242 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1243 *root, struct btrfs_path *path, struct btrfs_disk_key
1244 *key, u64 bytenr, int slot, int level)
1245 {
1246 struct extent_buffer *lower;
1247 int nritems;
1248
1249 BUG_ON(!path->nodes[level]);
1250 lower = path->nodes[level];
1251 nritems = btrfs_header_nritems(lower);
1252 if (slot > nritems)
1253 BUG();
1254 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1255 BUG();
1256 if (slot != nritems) {
1257 memmove_extent_buffer(lower,
1258 btrfs_node_key_ptr_offset(slot + 1),
1259 btrfs_node_key_ptr_offset(slot),
1260 (nritems - slot) * sizeof(struct btrfs_key_ptr));
1261 }
1262 btrfs_set_node_key(lower, key, slot);
1263 btrfs_set_node_blockptr(lower, slot, bytenr);
1264 btrfs_set_header_nritems(lower, nritems + 1);
1265 btrfs_mark_buffer_dirty(lower);
1266 return 0;
1267 }
1268
1269 /*
1270 * split the node at the specified level in path in two.
1271 * The path is corrected to point to the appropriate node after the split
1272 *
1273 * Before splitting this tries to make some room in the node by pushing
1274 * left and right, if either one works, it returns right away.
1275 *
1276 * returns 0 on success and < 0 on failure
1277 */
1278 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1279 *root, struct btrfs_path *path, int level)
1280 {
1281 struct extent_buffer *c;
1282 struct extent_buffer *split;
1283 struct btrfs_disk_key disk_key;
1284 int mid;
1285 int ret;
1286 int wret;
1287 u32 c_nritems;
1288
1289 c = path->nodes[level];
1290 if (c == root->node) {
1291 /* trying to split the root, lets make a new one */
1292 ret = insert_new_root(trans, root, path, level + 1);
1293 if (ret)
1294 return ret;
1295 } else {
1296 ret = push_nodes_for_insert(trans, root, path, level);
1297 c = path->nodes[level];
1298 if (!ret && btrfs_header_nritems(c) <
1299 BTRFS_NODEPTRS_PER_BLOCK(root) - 1)
1300 return 0;
1301 if (ret < 0)
1302 return ret;
1303 }
1304
1305 c_nritems = btrfs_header_nritems(c);
1306 split = btrfs_alloc_free_block(trans, root, root->nodesize,
1307 c->start, 0);
1308 if (IS_ERR(split))
1309 return PTR_ERR(split);
1310
1311 btrfs_set_header_flags(split, btrfs_header_flags(c));
1312 btrfs_set_header_level(split, btrfs_header_level(c));
1313 btrfs_set_header_bytenr(split, split->start);
1314 btrfs_set_header_generation(split, trans->transid);
1315 btrfs_set_header_owner(split, root->root_key.objectid);
1316 write_extent_buffer(split, root->fs_info->fsid,
1317 (unsigned long)btrfs_header_fsid(split),
1318 BTRFS_FSID_SIZE);
1319
1320 mid = (c_nritems + 1) / 2;
1321
1322 copy_extent_buffer(split, c,
1323 btrfs_node_key_ptr_offset(0),
1324 btrfs_node_key_ptr_offset(mid),
1325 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1326 btrfs_set_header_nritems(split, c_nritems - mid);
1327 btrfs_set_header_nritems(c, mid);
1328 ret = 0;
1329
1330 btrfs_mark_buffer_dirty(c);
1331 btrfs_mark_buffer_dirty(split);
1332
1333 btrfs_node_key(split, &disk_key, 0);
1334 wret = insert_ptr(trans, root, path, &disk_key, split->start,
1335 path->slots[level + 1] + 1,
1336 level + 1);
1337 if (wret)
1338 ret = wret;
1339
1340 if (path->slots[level] >= mid) {
1341 path->slots[level] -= mid;
1342 free_extent_buffer(c);
1343 path->nodes[level] = split;
1344 path->slots[level + 1] += 1;
1345 } else {
1346 free_extent_buffer(split);
1347 }
1348 return ret;
1349 }
1350
1351 /*
1352 * how many bytes are required to store the items in a leaf. start
1353 * and nr indicate which items in the leaf to check. This totals up the
1354 * space used both by the item structs and the item data
1355 */
1356 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1357 {
1358 int data_len;
1359 int nritems = btrfs_header_nritems(l);
1360 int end = min(nritems, start + nr) - 1;
1361
1362 if (!nr)
1363 return 0;
1364 data_len = btrfs_item_end_nr(l, start);
1365 data_len = data_len - btrfs_item_offset_nr(l, end);
1366 data_len += sizeof(struct btrfs_item) * nr;
1367 WARN_ON(data_len < 0);
1368 return data_len;
1369 }
1370
1371 /*
1372 * The space between the end of the leaf items and
1373 * the start of the leaf data. IOW, how much room
1374 * the leaf has left for both items and data
1375 */
1376 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1377 {
1378 int nritems = btrfs_header_nritems(leaf);
1379 int ret;
1380 ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1381 if (ret < 0) {
1382 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1383 ret, BTRFS_LEAF_DATA_SIZE(root),
1384 leaf_space_used(leaf, 0, nritems), nritems);
1385 }
1386 return ret;
1387 }
1388
1389 /*
1390 * push some data in the path leaf to the right, trying to free up at
1391 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1392 *
1393 * returns 1 if the push failed because the other node didn't have enough
1394 * room, 0 if everything worked out and < 0 if there were major errors.
1395 */
1396 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1397 *root, struct btrfs_path *path, int data_size)
1398 {
1399 struct extent_buffer *left = path->nodes[0];
1400 struct extent_buffer *right;
1401 struct extent_buffer *upper;
1402 struct btrfs_disk_key disk_key;
1403 int slot;
1404 int i;
1405 int free_space;
1406 int push_space = 0;
1407 int push_items = 0;
1408 struct btrfs_item *item;
1409 u32 left_nritems;
1410 u32 right_nritems;
1411 u32 data_end;
1412 u32 this_item_size;
1413 int ret;
1414
1415 slot = path->slots[1];
1416 if (!path->nodes[1]) {
1417 return 1;
1418 }
1419 upper = path->nodes[1];
1420 if (slot >= btrfs_header_nritems(upper) - 1)
1421 return 1;
1422
1423 right = read_tree_block(root, btrfs_node_blockptr(upper, slot + 1),
1424 root->leafsize);
1425 free_space = btrfs_leaf_free_space(root, right);
1426 if (free_space < data_size + sizeof(struct btrfs_item)) {
1427 free_extent_buffer(right);
1428 return 1;
1429 }
1430
1431 /* cow and double check */
1432 ret = btrfs_cow_block(trans, root, right, upper,
1433 slot + 1, &right);
1434 if (ret) {
1435 free_extent_buffer(right);
1436 return 1;
1437 }
1438 free_space = btrfs_leaf_free_space(root, right);
1439 if (free_space < data_size + sizeof(struct btrfs_item)) {
1440 free_extent_buffer(right);
1441 return 1;
1442 }
1443
1444 left_nritems = btrfs_header_nritems(left);
1445 if (left_nritems == 0) {
1446 free_extent_buffer(right);
1447 return 1;
1448 }
1449
1450 for (i = left_nritems - 1; i >= 1; i--) {
1451 item = btrfs_item_nr(left, i);
1452
1453 if (path->slots[0] == i)
1454 push_space += data_size + sizeof(*item);
1455
1456 if (!left->map_token) {
1457 map_extent_buffer(left, (unsigned long)item,
1458 sizeof(struct btrfs_item),
1459 &left->map_token, &left->kaddr,
1460 &left->map_start, &left->map_len,
1461 KM_USER1);
1462 }
1463
1464 this_item_size = btrfs_item_size(left, item);
1465 if (this_item_size + sizeof(*item) + push_space > free_space)
1466 break;
1467 push_items++;
1468 push_space += this_item_size + sizeof(*item);
1469 }
1470 if (left->map_token) {
1471 unmap_extent_buffer(left, left->map_token, KM_USER1);
1472 left->map_token = NULL;
1473 }
1474
1475 if (push_items == 0) {
1476 free_extent_buffer(right);
1477 return 1;
1478 }
1479
1480 if (push_items == left_nritems)
1481 WARN_ON(1);
1482
1483 /* push left to right */
1484 right_nritems = btrfs_header_nritems(right);
1485 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1486 push_space -= leaf_data_end(root, left);
1487
1488 /* make room in the right data area */
1489 data_end = leaf_data_end(root, right);
1490 memmove_extent_buffer(right,
1491 btrfs_leaf_data(right) + data_end - push_space,
1492 btrfs_leaf_data(right) + data_end,
1493 BTRFS_LEAF_DATA_SIZE(root) - data_end);
1494
1495 /* copy from the left data area */
1496 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1497 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1498 btrfs_leaf_data(left) + leaf_data_end(root, left),
1499 push_space);
1500
1501 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1502 btrfs_item_nr_offset(0),
1503 right_nritems * sizeof(struct btrfs_item));
1504
1505 /* copy the items from left to right */
1506 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1507 btrfs_item_nr_offset(left_nritems - push_items),
1508 push_items * sizeof(struct btrfs_item));
1509
1510 /* update the item pointers */
1511 right_nritems += push_items;
1512 btrfs_set_header_nritems(right, right_nritems);
1513 push_space = BTRFS_LEAF_DATA_SIZE(root);
1514
1515 for (i = 0; i < right_nritems; i++) {
1516 item = btrfs_item_nr(right, i);
1517 if (!right->map_token) {
1518 map_extent_buffer(right, (unsigned long)item,
1519 sizeof(struct btrfs_item),
1520 &right->map_token, &right->kaddr,
1521 &right->map_start, &right->map_len,
1522 KM_USER1);
1523 }
1524 push_space -= btrfs_item_size(right, item);
1525 btrfs_set_item_offset(right, item, push_space);
1526 }
1527
1528 if (right->map_token) {
1529 unmap_extent_buffer(right, right->map_token, KM_USER1);
1530 right->map_token = NULL;
1531 }
1532 left_nritems -= push_items;
1533 btrfs_set_header_nritems(left, left_nritems);
1534
1535 btrfs_mark_buffer_dirty(left);
1536 btrfs_mark_buffer_dirty(right);
1537
1538 btrfs_item_key(right, &disk_key, 0);
1539 btrfs_set_node_key(upper, &disk_key, slot + 1);
1540 btrfs_mark_buffer_dirty(upper);
1541
1542 /* then fixup the leaf pointer in the path */
1543 if (path->slots[0] >= left_nritems) {
1544 path->slots[0] -= left_nritems;
1545 free_extent_buffer(path->nodes[0]);
1546 path->nodes[0] = right;
1547 path->slots[1] += 1;
1548 } else {
1549 free_extent_buffer(right);
1550 }
1551 return 0;
1552 }
1553 /*
1554 * push some data in the path leaf to the left, trying to free up at
1555 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1556 */
1557 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1558 *root, struct btrfs_path *path, int data_size)
1559 {
1560 struct btrfs_disk_key disk_key;
1561 struct extent_buffer *right = path->nodes[0];
1562 struct extent_buffer *left;
1563 int slot;
1564 int i;
1565 int free_space;
1566 int push_space = 0;
1567 int push_items = 0;
1568 struct btrfs_item *item;
1569 u32 old_left_nritems;
1570 u32 right_nritems;
1571 int ret = 0;
1572 int wret;
1573 u32 this_item_size;
1574 u32 old_left_item_size;
1575
1576 slot = path->slots[1];
1577 if (slot == 0)
1578 return 1;
1579 if (!path->nodes[1])
1580 return 1;
1581
1582 left = read_tree_block(root, btrfs_node_blockptr(path->nodes[1],
1583 slot - 1), root->leafsize);
1584 free_space = btrfs_leaf_free_space(root, left);
1585 if (free_space < data_size + sizeof(struct btrfs_item)) {
1586 free_extent_buffer(left);
1587 return 1;
1588 }
1589
1590 /* cow and double check */
1591 ret = btrfs_cow_block(trans, root, left,
1592 path->nodes[1], slot - 1, &left);
1593 if (ret) {
1594 /* we hit -ENOSPC, but it isn't fatal here */
1595 free_extent_buffer(left);
1596 return 1;
1597 }
1598 free_space = btrfs_leaf_free_space(root, left);
1599 if (free_space < data_size + sizeof(struct btrfs_item)) {
1600 free_extent_buffer(left);
1601 return 1;
1602 }
1603
1604 right_nritems = btrfs_header_nritems(right);
1605 if (right_nritems == 0) {
1606 free_extent_buffer(left);
1607 return 1;
1608 }
1609
1610 for (i = 0; i < right_nritems - 1; i++) {
1611 item = btrfs_item_nr(right, i);
1612 if (!right->map_token) {
1613 map_extent_buffer(right, (unsigned long)item,
1614 sizeof(struct btrfs_item),
1615 &right->map_token, &right->kaddr,
1616 &right->map_start, &right->map_len,
1617 KM_USER1);
1618 }
1619
1620 if (path->slots[0] == i)
1621 push_space += data_size + sizeof(*item);
1622
1623 this_item_size = btrfs_item_size(right, item);
1624 if (this_item_size + sizeof(*item) + push_space > free_space)
1625 break;
1626
1627 push_items++;
1628 push_space += this_item_size + sizeof(*item);
1629 }
1630
1631 if (right->map_token) {
1632 unmap_extent_buffer(right, right->map_token, KM_USER1);
1633 right->map_token = NULL;
1634 }
1635
1636 if (push_items == 0) {
1637 free_extent_buffer(left);
1638 return 1;
1639 }
1640 if (push_items == btrfs_header_nritems(right))
1641 WARN_ON(1);
1642
1643 /* push data from right to left */
1644 copy_extent_buffer(left, right,
1645 btrfs_item_nr_offset(btrfs_header_nritems(left)),
1646 btrfs_item_nr_offset(0),
1647 push_items * sizeof(struct btrfs_item));
1648
1649 push_space = BTRFS_LEAF_DATA_SIZE(root) -
1650 btrfs_item_offset_nr(right, push_items -1);
1651
1652 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
1653 leaf_data_end(root, left) - push_space,
1654 btrfs_leaf_data(right) +
1655 btrfs_item_offset_nr(right, push_items - 1),
1656 push_space);
1657 old_left_nritems = btrfs_header_nritems(left);
1658 BUG_ON(old_left_nritems < 0);
1659
1660 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
1661 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1662 u32 ioff;
1663
1664 item = btrfs_item_nr(left, i);
1665 if (!left->map_token) {
1666 map_extent_buffer(left, (unsigned long)item,
1667 sizeof(struct btrfs_item),
1668 &left->map_token, &left->kaddr,
1669 &left->map_start, &left->map_len,
1670 KM_USER1);
1671 }
1672
1673 ioff = btrfs_item_offset(left, item);
1674 btrfs_set_item_offset(left, item,
1675 ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
1676 }
1677 btrfs_set_header_nritems(left, old_left_nritems + push_items);
1678 if (left->map_token) {
1679 unmap_extent_buffer(left, left->map_token, KM_USER1);
1680 left->map_token = NULL;
1681 }
1682
1683 /* fixup right node */
1684 push_space = btrfs_item_offset_nr(right, push_items - 1) -
1685 leaf_data_end(root, right);
1686 memmove_extent_buffer(right, btrfs_leaf_data(right) +
1687 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1688 btrfs_leaf_data(right) +
1689 leaf_data_end(root, right), push_space);
1690
1691 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
1692 btrfs_item_nr_offset(push_items),
1693 (btrfs_header_nritems(right) - push_items) *
1694 sizeof(struct btrfs_item));
1695
1696 right_nritems = btrfs_header_nritems(right) - push_items;
1697 btrfs_set_header_nritems(right, right_nritems);
1698 push_space = BTRFS_LEAF_DATA_SIZE(root);
1699
1700 for (i = 0; i < right_nritems; i++) {
1701 item = btrfs_item_nr(right, i);
1702
1703 if (!right->map_token) {
1704 map_extent_buffer(right, (unsigned long)item,
1705 sizeof(struct btrfs_item),
1706 &right->map_token, &right->kaddr,
1707 &right->map_start, &right->map_len,
1708 KM_USER1);
1709 }
1710
1711 push_space = push_space - btrfs_item_size(right, item);
1712 btrfs_set_item_offset(right, item, push_space);
1713 }
1714 if (right->map_token) {
1715 unmap_extent_buffer(right, right->map_token, KM_USER1);
1716 right->map_token = NULL;
1717 }
1718
1719 btrfs_mark_buffer_dirty(left);
1720 btrfs_mark_buffer_dirty(right);
1721
1722 btrfs_item_key(right, &disk_key, 0);
1723 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1724 if (wret)
1725 ret = wret;
1726
1727 /* then fixup the leaf pointer in the path */
1728 if (path->slots[0] < push_items) {
1729 path->slots[0] += old_left_nritems;
1730 free_extent_buffer(path->nodes[0]);
1731 path->nodes[0] = left;
1732 path->slots[1] -= 1;
1733 } else {
1734 free_extent_buffer(left);
1735 path->slots[0] -= push_items;
1736 }
1737 BUG_ON(path->slots[0] < 0);
1738 return ret;
1739 }
1740
1741 /*
1742 * split the path's leaf in two, making sure there is at least data_size
1743 * available for the resulting leaf level of the path.
1744 *
1745 * returns 0 if all went well and < 0 on failure.
1746 */
1747 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1748 *root, struct btrfs_key *ins_key,
1749 struct btrfs_path *path, int data_size)
1750 {
1751 struct extent_buffer *l;
1752 u32 nritems;
1753 int mid;
1754 int slot;
1755 struct extent_buffer *right;
1756 int space_needed = data_size + sizeof(struct btrfs_item);
1757 int data_copy_size;
1758 int rt_data_off;
1759 int i;
1760 int ret = 0;
1761 int wret;
1762 int double_split = 0;
1763 struct btrfs_disk_key disk_key;
1764
1765 /* first try to make some room by pushing left and right */
1766 wret = push_leaf_left(trans, root, path, data_size);
1767 if (wret < 0) {
1768 return wret;
1769 }
1770 if (wret) {
1771 wret = push_leaf_right(trans, root, path, data_size);
1772 if (wret < 0)
1773 return wret;
1774 }
1775 l = path->nodes[0];
1776
1777 /* did the pushes work? */
1778 if (btrfs_leaf_free_space(root, l) >=
1779 sizeof(struct btrfs_item) + data_size) {
1780 return 0;
1781 }
1782
1783 if (!path->nodes[1]) {
1784 ret = insert_new_root(trans, root, path, 1);
1785 if (ret)
1786 return ret;
1787 }
1788 slot = path->slots[0];
1789 nritems = btrfs_header_nritems(l);
1790 mid = (nritems + 1)/ 2;
1791
1792 right = btrfs_alloc_free_block(trans, root, root->leafsize,
1793 l->start, 0);
1794 if (IS_ERR(right))
1795 return PTR_ERR(right);
1796
1797 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
1798 btrfs_set_header_bytenr(right, right->start);
1799 btrfs_set_header_generation(right, trans->transid);
1800 btrfs_set_header_owner(right, root->root_key.objectid);
1801 btrfs_set_header_level(right, 0);
1802 write_extent_buffer(right, root->fs_info->fsid,
1803 (unsigned long)btrfs_header_fsid(right),
1804 BTRFS_FSID_SIZE);
1805
1806 if (mid <= slot) {
1807 if (nritems == 1 ||
1808 leaf_space_used(l, mid, nritems - mid) + space_needed >
1809 BTRFS_LEAF_DATA_SIZE(root)) {
1810 if (slot >= nritems) {
1811 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1812 btrfs_set_header_nritems(right, 0);
1813 wret = insert_ptr(trans, root, path,
1814 &disk_key, right->start,
1815 path->slots[1] + 1, 1);
1816 if (wret)
1817 ret = wret;
1818 free_extent_buffer(path->nodes[0]);
1819 path->nodes[0] = right;
1820 path->slots[0] = 0;
1821 path->slots[1] += 1;
1822 return ret;
1823 }
1824 mid = slot;
1825 if (mid != nritems &&
1826 leaf_space_used(l, mid, nritems - mid) +
1827 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
1828 double_split = 1;
1829 }
1830 }
1831 } else {
1832 if (leaf_space_used(l, 0, mid + 1) + space_needed >
1833 BTRFS_LEAF_DATA_SIZE(root)) {
1834 if (slot == 0) {
1835 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1836 btrfs_set_header_nritems(right, 0);
1837 wret = insert_ptr(trans, root, path,
1838 &disk_key,
1839 right->start,
1840 path->slots[1], 1);
1841 if (wret)
1842 ret = wret;
1843 free_extent_buffer(path->nodes[0]);
1844 path->nodes[0] = right;
1845 path->slots[0] = 0;
1846 if (path->slots[1] == 0) {
1847 wret = fixup_low_keys(trans, root,
1848 path, &disk_key, 1);
1849 if (wret)
1850 ret = wret;
1851 }
1852 return ret;
1853 }
1854 mid = slot;
1855 double_split = 1;
1856 }
1857 }
1858 nritems = nritems - mid;
1859 btrfs_set_header_nritems(right, nritems);
1860 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
1861
1862 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
1863 btrfs_item_nr_offset(mid),
1864 nritems * sizeof(struct btrfs_item));
1865
1866 copy_extent_buffer(right, l,
1867 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
1868 data_copy_size, btrfs_leaf_data(l) +
1869 leaf_data_end(root, l), data_copy_size);
1870
1871 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
1872 btrfs_item_end_nr(l, mid);
1873
1874 for (i = 0; i < nritems; i++) {
1875 struct btrfs_item *item = btrfs_item_nr(right, i);
1876 u32 ioff;
1877
1878 if (!right->map_token) {
1879 map_extent_buffer(right, (unsigned long)item,
1880 sizeof(struct btrfs_item),
1881 &right->map_token, &right->kaddr,
1882 &right->map_start, &right->map_len,
1883 KM_USER1);
1884 }
1885
1886 ioff = btrfs_item_offset(right, item);
1887 btrfs_set_item_offset(right, item, ioff + rt_data_off);
1888 }
1889
1890 if (right->map_token) {
1891 unmap_extent_buffer(right, right->map_token, KM_USER1);
1892 right->map_token = NULL;
1893 }
1894
1895 btrfs_set_header_nritems(l, mid);
1896 ret = 0;
1897 btrfs_item_key(right, &disk_key, 0);
1898 wret = insert_ptr(trans, root, path, &disk_key, right->start,
1899 path->slots[1] + 1, 1);
1900 if (wret)
1901 ret = wret;
1902
1903 btrfs_mark_buffer_dirty(right);
1904 btrfs_mark_buffer_dirty(l);
1905 BUG_ON(path->slots[0] != slot);
1906
1907 if (mid <= slot) {
1908 free_extent_buffer(path->nodes[0]);
1909 path->nodes[0] = right;
1910 path->slots[0] -= mid;
1911 path->slots[1] += 1;
1912 } else
1913 free_extent_buffer(right);
1914
1915 BUG_ON(path->slots[0] < 0);
1916
1917 if (!double_split) {
1918 return ret;
1919 }
1920
1921 right = btrfs_alloc_free_block(trans, root, root->leafsize,
1922 l->start, 0);
1923 if (IS_ERR(right))
1924 return PTR_ERR(right);
1925
1926 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
1927 btrfs_set_header_bytenr(right, right->start);
1928 btrfs_set_header_generation(right, trans->transid);
1929 btrfs_set_header_owner(right, root->root_key.objectid);
1930 btrfs_set_header_level(right, 0);
1931 write_extent_buffer(right, root->fs_info->fsid,
1932 (unsigned long)btrfs_header_fsid(right),
1933 BTRFS_FSID_SIZE);
1934
1935 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1936 btrfs_set_header_nritems(right, 0);
1937 wret = insert_ptr(trans, root, path,
1938 &disk_key, right->start,
1939 path->slots[1], 1);
1940 if (wret)
1941 ret = wret;
1942 if (path->slots[1] == 0) {
1943 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1944 if (wret)
1945 ret = wret;
1946 }
1947 free_extent_buffer(path->nodes[0]);
1948 path->nodes[0] = right;
1949 path->slots[0] = 0;
1950 return ret;
1951 }
1952
1953 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
1954 struct btrfs_root *root,
1955 struct btrfs_path *path,
1956 u32 new_size)
1957 {
1958 int ret = 0;
1959 int slot;
1960 int slot_orig;
1961 struct extent_buffer *leaf;
1962 struct btrfs_item *item;
1963 u32 nritems;
1964 unsigned int data_end;
1965 unsigned int old_data_start;
1966 unsigned int old_size;
1967 unsigned int size_diff;
1968 int i;
1969
1970 slot_orig = path->slots[0];
1971 leaf = path->nodes[0];
1972
1973 nritems = btrfs_header_nritems(leaf);
1974 data_end = leaf_data_end(root, leaf);
1975
1976 slot = path->slots[0];
1977 old_data_start = btrfs_item_offset_nr(leaf, slot);
1978 old_size = btrfs_item_size_nr(leaf, slot);
1979 BUG_ON(old_size <= new_size);
1980 size_diff = old_size - new_size;
1981
1982 BUG_ON(slot < 0);
1983 BUG_ON(slot >= nritems);
1984
1985 /*
1986 * item0..itemN ... dataN.offset..dataN.size .. data0.size
1987 */
1988 /* first correct the data pointers */
1989 for (i = slot; i < nritems; i++) {
1990 u32 ioff;
1991 item = btrfs_item_nr(leaf, i);
1992
1993 if (!leaf->map_token) {
1994 map_extent_buffer(leaf, (unsigned long)item,
1995 sizeof(struct btrfs_item),
1996 &leaf->map_token, &leaf->kaddr,
1997 &leaf->map_start, &leaf->map_len,
1998 KM_USER1);
1999 }
2000
2001 ioff = btrfs_item_offset(leaf, item);
2002 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2003 }
2004
2005 if (leaf->map_token) {
2006 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2007 leaf->map_token = NULL;
2008 }
2009
2010 /* shift the data */
2011 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2012 data_end + size_diff, btrfs_leaf_data(leaf) +
2013 data_end, old_data_start + new_size - data_end);
2014
2015 item = btrfs_item_nr(leaf, slot);
2016 btrfs_set_item_size(leaf, item, new_size);
2017 btrfs_mark_buffer_dirty(leaf);
2018
2019 ret = 0;
2020 if (btrfs_leaf_free_space(root, leaf) < 0) {
2021 btrfs_print_leaf(root, leaf);
2022 BUG();
2023 }
2024 return ret;
2025 }
2026
2027 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2028 struct btrfs_root *root, struct btrfs_path *path,
2029 u32 data_size)
2030 {
2031 int ret = 0;
2032 int slot;
2033 int slot_orig;
2034 struct extent_buffer *leaf;
2035 struct btrfs_item *item;
2036 u32 nritems;
2037 unsigned int data_end;
2038 unsigned int old_data;
2039 unsigned int old_size;
2040 int i;
2041
2042 slot_orig = path->slots[0];
2043 leaf = path->nodes[0];
2044
2045 nritems = btrfs_header_nritems(leaf);
2046 data_end = leaf_data_end(root, leaf);
2047
2048 if (btrfs_leaf_free_space(root, leaf) < data_size) {
2049 btrfs_print_leaf(root, leaf);
2050 BUG();
2051 }
2052 slot = path->slots[0];
2053 old_data = btrfs_item_end_nr(leaf, slot);
2054
2055 BUG_ON(slot < 0);
2056 if (slot >= nritems) {
2057 btrfs_print_leaf(root, leaf);
2058 printk("slot %d too large, nritems %d\n", slot, nritems);
2059 BUG_ON(1);
2060 }
2061
2062 /*
2063 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2064 */
2065 /* first correct the data pointers */
2066 for (i = slot; i < nritems; i++) {
2067 u32 ioff;
2068 item = btrfs_item_nr(leaf, i);
2069
2070 if (!leaf->map_token) {
2071 map_extent_buffer(leaf, (unsigned long)item,
2072 sizeof(struct btrfs_item),
2073 &leaf->map_token, &leaf->kaddr,
2074 &leaf->map_start, &leaf->map_len,
2075 KM_USER1);
2076 }
2077 ioff = btrfs_item_offset(leaf, item);
2078 btrfs_set_item_offset(leaf, item, ioff - data_size);
2079 }
2080
2081 if (leaf->map_token) {
2082 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2083 leaf->map_token = NULL;
2084 }
2085
2086 /* shift the data */
2087 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2088 data_end - data_size, btrfs_leaf_data(leaf) +
2089 data_end, old_data - data_end);
2090
2091 data_end = old_data;
2092 old_size = btrfs_item_size_nr(leaf, slot);
2093 item = btrfs_item_nr(leaf, slot);
2094 btrfs_set_item_size(leaf, item, old_size + data_size);
2095 btrfs_mark_buffer_dirty(leaf);
2096
2097 ret = 0;
2098 if (btrfs_leaf_free_space(root, leaf) < 0) {
2099 btrfs_print_leaf(root, leaf);
2100 BUG();
2101 }
2102 return ret;
2103 }
2104
2105 /*
2106 * Given a key and some data, insert an item into the tree.
2107 * This does all the path init required, making room in the tree if needed.
2108 */
2109 int btrfs_insert_empty_item(struct btrfs_trans_handle *trans,
2110 struct btrfs_root *root,
2111 struct btrfs_path *path,
2112 struct btrfs_key *cpu_key, u32 data_size)
2113 {
2114 struct extent_buffer *leaf;
2115 struct btrfs_item *item;
2116 int ret = 0;
2117 int slot;
2118 int slot_orig;
2119 u32 nritems;
2120 unsigned int data_end;
2121 struct btrfs_disk_key disk_key;
2122
2123 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2124
2125 /* create a root if there isn't one */
2126 if (!root->node)
2127 BUG();
2128
2129 ret = btrfs_search_slot(trans, root, cpu_key, path, data_size, 1);
2130 if (ret == 0) {
2131 return -EEXIST;
2132 }
2133 if (ret < 0)
2134 goto out;
2135
2136 slot_orig = path->slots[0];
2137 leaf = path->nodes[0];
2138
2139 nritems = btrfs_header_nritems(leaf);
2140 data_end = leaf_data_end(root, leaf);
2141
2142 if (btrfs_leaf_free_space(root, leaf) <
2143 sizeof(struct btrfs_item) + data_size) {
2144 btrfs_print_leaf(root, leaf);
2145 printk("not enough freespace need %u have %d\n",
2146 data_size, btrfs_leaf_free_space(root, leaf));
2147 BUG();
2148 }
2149
2150 slot = path->slots[0];
2151 BUG_ON(slot < 0);
2152
2153 if (slot != nritems) {
2154 int i;
2155 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2156
2157 if (old_data < data_end) {
2158 btrfs_print_leaf(root, leaf);
2159 printk("slot %d old_data %d data_end %d\n",
2160 slot, old_data, data_end);
2161 BUG_ON(1);
2162 }
2163 /*
2164 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2165 */
2166 /* first correct the data pointers */
2167 WARN_ON(leaf->map_token);
2168 for (i = slot; i < nritems; i++) {
2169 u32 ioff;
2170
2171 item = btrfs_item_nr(leaf, i);
2172 if (!leaf->map_token) {
2173 map_extent_buffer(leaf, (unsigned long)item,
2174 sizeof(struct btrfs_item),
2175 &leaf->map_token, &leaf->kaddr,
2176 &leaf->map_start, &leaf->map_len,
2177 KM_USER1);
2178 }
2179
2180 ioff = btrfs_item_offset(leaf, item);
2181 btrfs_set_item_offset(leaf, item, ioff - data_size);
2182 }
2183 if (leaf->map_token) {
2184 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2185 leaf->map_token = NULL;
2186 }
2187
2188 /* shift the items */
2189 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1),
2190 btrfs_item_nr_offset(slot),
2191 (nritems - slot) * sizeof(struct btrfs_item));
2192
2193 /* shift the data */
2194 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2195 data_end - data_size, btrfs_leaf_data(leaf) +
2196 data_end, old_data - data_end);
2197 data_end = old_data;
2198 }
2199
2200 /* setup the item for the new data */
2201 btrfs_set_item_key(leaf, &disk_key, slot);
2202 item = btrfs_item_nr(leaf, slot);
2203 btrfs_set_item_offset(leaf, item, data_end - data_size);
2204 btrfs_set_item_size(leaf, item, data_size);
2205 btrfs_set_header_nritems(leaf, nritems + 1);
2206 btrfs_mark_buffer_dirty(leaf);
2207
2208 ret = 0;
2209 if (slot == 0)
2210 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2211
2212 if (btrfs_leaf_free_space(root, leaf) < 0) {
2213 btrfs_print_leaf(root, leaf);
2214 BUG();
2215 }
2216 out:
2217 return ret;
2218 }
2219
2220 /*
2221 * Given a key and some data, insert an item into the tree.
2222 * This does all the path init required, making room in the tree if needed.
2223 */
2224 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2225 *root, struct btrfs_key *cpu_key, void *data, u32
2226 data_size)
2227 {
2228 int ret = 0;
2229 struct btrfs_path *path;
2230 struct extent_buffer *leaf;
2231 unsigned long ptr;
2232
2233 path = btrfs_alloc_path();
2234 BUG_ON(!path);
2235 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2236 if (!ret) {
2237 leaf = path->nodes[0];
2238 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2239 write_extent_buffer(leaf, data, ptr, data_size);
2240 btrfs_mark_buffer_dirty(leaf);
2241 }
2242 btrfs_free_path(path);
2243 return ret;
2244 }
2245
2246 /*
2247 * delete the pointer from a given node.
2248 *
2249 * If the delete empties a node, the node is removed from the tree,
2250 * continuing all the way the root if required. The root is converted into
2251 * a leaf if all the nodes are emptied.
2252 */
2253 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2254 struct btrfs_path *path, int level, int slot)
2255 {
2256 struct extent_buffer *parent = path->nodes[level];
2257 u32 nritems;
2258 int ret = 0;
2259 int wret;
2260
2261 nritems = btrfs_header_nritems(parent);
2262 if (slot != nritems -1) {
2263 memmove_extent_buffer(parent,
2264 btrfs_node_key_ptr_offset(slot),
2265 btrfs_node_key_ptr_offset(slot + 1),
2266 sizeof(struct btrfs_key_ptr) *
2267 (nritems - slot - 1));
2268 }
2269 nritems--;
2270 btrfs_set_header_nritems(parent, nritems);
2271 if (nritems == 0 && parent == root->node) {
2272 BUG_ON(btrfs_header_level(root->node) != 1);
2273 /* just turn the root into a leaf and break */
2274 btrfs_set_header_level(root->node, 0);
2275 } else if (slot == 0) {
2276 struct btrfs_disk_key disk_key;
2277
2278 btrfs_node_key(parent, &disk_key, 0);
2279 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2280 if (wret)
2281 ret = wret;
2282 }
2283 btrfs_mark_buffer_dirty(parent);
2284 return ret;
2285 }
2286
2287 /*
2288 * delete the item at the leaf level in path. If that empties
2289 * the leaf, remove it from the tree
2290 */
2291 int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2292 struct btrfs_path *path)
2293 {
2294 int slot;
2295 struct extent_buffer *leaf;
2296 struct btrfs_item *item;
2297 int doff;
2298 int dsize;
2299 int ret = 0;
2300 int wret;
2301 u32 nritems;
2302
2303 leaf = path->nodes[0];
2304 slot = path->slots[0];
2305 doff = btrfs_item_offset_nr(leaf, slot);
2306 dsize = btrfs_item_size_nr(leaf, slot);
2307 nritems = btrfs_header_nritems(leaf);
2308
2309 if (slot != nritems - 1) {
2310 int i;
2311 int data_end = leaf_data_end(root, leaf);
2312
2313 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2314 data_end + dsize,
2315 btrfs_leaf_data(leaf) + data_end,
2316 doff - data_end);
2317
2318 for (i = slot + 1; i < nritems; i++) {
2319 u32 ioff;
2320
2321 item = btrfs_item_nr(leaf, i);
2322 if (!leaf->map_token) {
2323 map_extent_buffer(leaf, (unsigned long)item,
2324 sizeof(struct btrfs_item),
2325 &leaf->map_token, &leaf->kaddr,
2326 &leaf->map_start, &leaf->map_len,
2327 KM_USER1);
2328 }
2329 ioff = btrfs_item_offset(leaf, item);
2330 btrfs_set_item_offset(leaf, item, ioff + dsize);
2331 }
2332
2333 if (leaf->map_token) {
2334 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2335 leaf->map_token = NULL;
2336 }
2337
2338 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2339 btrfs_item_nr_offset(slot + 1),
2340 sizeof(struct btrfs_item) *
2341 (nritems - slot - 1));
2342 }
2343 btrfs_set_header_nritems(leaf, nritems - 1);
2344 nritems--;
2345
2346 /* delete the leaf if we've emptied it */
2347 if (nritems == 0) {
2348 if (leaf == root->node) {
2349 btrfs_set_header_level(leaf, 0);
2350 } else {
2351 clean_tree_block(trans, root, leaf);
2352 wait_on_tree_block_writeback(root, leaf);
2353 wret = del_ptr(trans, root, path, 1, path->slots[1]);
2354 if (wret)
2355 ret = wret;
2356 wret = btrfs_free_extent(trans, root,
2357 leaf->start, leaf->len, 1);
2358 if (wret)
2359 ret = wret;
2360 }
2361 } else {
2362 int used = leaf_space_used(leaf, 0, nritems);
2363 if (slot == 0) {
2364 struct btrfs_disk_key disk_key;
2365
2366 btrfs_item_key(leaf, &disk_key, 0);
2367 wret = fixup_low_keys(trans, root, path,
2368 &disk_key, 1);
2369 if (wret)
2370 ret = wret;
2371 }
2372
2373 /* delete the leaf if it is mostly empty */
2374 if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) {
2375 /* push_leaf_left fixes the path.
2376 * make sure the path still points to our leaf
2377 * for possible call to del_ptr below
2378 */
2379 slot = path->slots[1];
2380 extent_buffer_get(leaf);
2381
2382 wret = push_leaf_left(trans, root, path, 1);
2383 if (wret < 0 && wret != -ENOSPC)
2384 ret = wret;
2385
2386 if (path->nodes[0] == leaf &&
2387 btrfs_header_nritems(leaf)) {
2388 wret = push_leaf_right(trans, root, path, 1);
2389 if (wret < 0 && wret != -ENOSPC)
2390 ret = wret;
2391 }
2392
2393 if (btrfs_header_nritems(leaf) == 0) {
2394 u64 bytenr = leaf->start;
2395 u32 blocksize = leaf->len;
2396
2397 clean_tree_block(trans, root, leaf);
2398 wait_on_tree_block_writeback(root, leaf);
2399
2400 wret = del_ptr(trans, root, path, 1, slot);
2401 if (wret)
2402 ret = wret;
2403
2404 free_extent_buffer(leaf);
2405 wret = btrfs_free_extent(trans, root, bytenr,
2406 blocksize, 1);
2407 if (wret)
2408 ret = wret;
2409 } else {
2410 btrfs_mark_buffer_dirty(leaf);
2411 free_extent_buffer(leaf);
2412 }
2413 } else {
2414 btrfs_mark_buffer_dirty(leaf);
2415 }
2416 }
2417 return ret;
2418 }
2419
2420 /*
2421 * walk up the tree as far as required to find the next leaf.
2422 * returns 0 if it found something or 1 if there are no greater leaves.
2423 * returns < 0 on io errors.
2424 */
2425 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2426 {
2427 int slot;
2428 int level = 1;
2429 u64 bytenr;
2430 struct extent_buffer *c;
2431 struct extent_buffer *next = NULL;
2432
2433 while(level < BTRFS_MAX_LEVEL) {
2434 if (!path->nodes[level])
2435 return 1;
2436
2437 slot = path->slots[level] + 1;
2438 c = path->nodes[level];
2439 if (slot >= btrfs_header_nritems(c)) {
2440 level++;
2441 continue;
2442 }
2443
2444 bytenr = btrfs_node_blockptr(c, slot);
2445 if (next)
2446 free_extent_buffer(next);
2447
2448 if (path->reada)
2449 reada_for_search(root, path, level, slot);
2450
2451 next = read_tree_block(root, bytenr,
2452 btrfs_level_size(root, level -1));
2453 break;
2454 }
2455 path->slots[level] = slot;
2456 while(1) {
2457 level--;
2458 c = path->nodes[level];
2459 free_extent_buffer(c);
2460 path->nodes[level] = next;
2461 path->slots[level] = 0;
2462 if (!level)
2463 break;
2464 if (path->reada)
2465 reada_for_search(root, path, level, 0);
2466 next = read_tree_block(root, btrfs_node_blockptr(next, 0),
2467 btrfs_level_size(root, level - 1));
2468 }
2469 return 0;
2470 }
Linux kernel - Deliverables
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