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[deliverable/linux.git] / fs / btrfs / ctree.c
1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/sched.h>
20 #include "ctree.h"
21 #include "disk-io.h"
22 #include "transaction.h"
23 #include "print-tree.h"
24
25 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
26 *root, struct btrfs_path *path, int level);
27 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
28 *root, struct btrfs_key *ins_key,
29 struct btrfs_path *path, int data_size);
30 static int push_node_left(struct btrfs_trans_handle *trans,
31 struct btrfs_root *root, struct extent_buffer *dst,
32 struct extent_buffer *src);
33 static int balance_node_right(struct btrfs_trans_handle *trans,
34 struct btrfs_root *root,
35 struct extent_buffer *dst_buf,
36 struct extent_buffer *src_buf);
37 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
38 struct btrfs_path *path, int level, int slot);
39
40 inline void btrfs_init_path(struct btrfs_path *p)
41 {
42 memset(p, 0, sizeof(*p));
43 }
44
45 struct btrfs_path *btrfs_alloc_path(void)
46 {
47 struct btrfs_path *path;
48 path = kmem_cache_alloc(btrfs_path_cachep, GFP_NOFS);
49 if (path) {
50 btrfs_init_path(path);
51 path->reada = 1;
52 }
53 return path;
54 }
55
56 void btrfs_free_path(struct btrfs_path *p)
57 {
58 btrfs_release_path(NULL, p);
59 kmem_cache_free(btrfs_path_cachep, p);
60 }
61
62 void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
63 {
64 int i;
65 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
66 if (!p->nodes[i])
67 break;
68 free_extent_buffer(p->nodes[i]);
69 }
70 memset(p, 0, sizeof(*p));
71 }
72
73 static int __btrfs_cow_block(struct btrfs_trans_handle *trans,
74 struct btrfs_root *root,
75 struct extent_buffer *buf,
76 struct extent_buffer *parent, int parent_slot,
77 struct extent_buffer **cow_ret,
78 u64 search_start, u64 empty_size)
79 {
80 struct extent_buffer *cow;
81 int ret = 0;
82 int different_trans = 0;
83
84 WARN_ON(root->ref_cows && trans->transid != root->last_trans);
85
86 cow = btrfs_alloc_free_block(trans, root, buf->len,
87 search_start, empty_size);
88 if (IS_ERR(cow))
89 return PTR_ERR(cow);
90
91 copy_extent_buffer(cow, buf, 0, 0, cow->len);
92 btrfs_set_header_bytenr(cow, cow->start);
93 btrfs_set_header_generation(cow, trans->transid);
94 btrfs_set_header_owner(cow, root->root_key.objectid);
95
96 WARN_ON(btrfs_header_generation(buf) > trans->transid);
97 if (btrfs_header_generation(buf) != trans->transid) {
98 different_trans = 1;
99 ret = btrfs_inc_ref(trans, root, buf);
100 if (ret)
101 return ret;
102 } else {
103 clean_tree_block(trans, root, buf);
104 }
105
106 if (buf == root->node) {
107 root->node = cow;
108 extent_buffer_get(cow);
109 if (buf != root->commit_root) {
110 btrfs_free_extent(trans, root, buf->start,
111 buf->len, 1);
112 }
113 free_extent_buffer(buf);
114 } else {
115 btrfs_set_node_blockptr(parent, parent_slot,
116 cow->start);
117 btrfs_mark_buffer_dirty(parent);
118 WARN_ON(btrfs_header_generation(parent) != trans->transid);
119 btrfs_free_extent(trans, root, buf->start, buf->len, 1);
120 }
121 free_extent_buffer(buf);
122 btrfs_mark_buffer_dirty(cow);
123 *cow_ret = cow;
124 return 0;
125 }
126
127 int btrfs_cow_block(struct btrfs_trans_handle *trans,
128 struct btrfs_root *root, struct extent_buffer *buf,
129 struct extent_buffer *parent, int parent_slot,
130 struct extent_buffer **cow_ret)
131 {
132 u64 search_start;
133 int ret;
134 if (trans->transaction != root->fs_info->running_transaction) {
135 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
136 root->fs_info->running_transaction->transid);
137 WARN_ON(1);
138 }
139 if (trans->transid != root->fs_info->generation) {
140 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
141 root->fs_info->generation);
142 WARN_ON(1);
143 }
144 if (btrfs_header_generation(buf) == trans->transid) {
145 *cow_ret = buf;
146 return 0;
147 }
148
149 search_start = buf->start & ~((u64)BTRFS_BLOCK_GROUP_SIZE - 1);
150 ret = __btrfs_cow_block(trans, root, buf, parent,
151 parent_slot, cow_ret, search_start, 0);
152 return ret;
153 }
154
155 static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
156 {
157 if (blocknr < other && other - (blocknr + blocksize) < 32768)
158 return 1;
159 if (blocknr > other && blocknr - (other + blocksize) < 32768)
160 return 1;
161 return 0;
162 }
163
164 static int should_defrag_leaf(struct extent_buffer *leaf)
165 {
166 struct btrfs_key key;
167 u32 nritems;
168
169 if (btrfs_buffer_defrag(leaf))
170 return 1;
171
172 nritems = btrfs_header_nritems(leaf);
173 if (nritems == 0)
174 return 0;
175
176 btrfs_item_key_to_cpu(leaf, &key, 0);
177 if (key.type == BTRFS_DIR_ITEM_KEY)
178 return 1;
179
180
181 btrfs_item_key_to_cpu(leaf, &key, nritems - 1);
182 if (key.type == BTRFS_DIR_ITEM_KEY)
183 return 1;
184 if (nritems > 4) {
185 btrfs_item_key_to_cpu(leaf, &key, nritems / 2);
186 if (key.type == BTRFS_DIR_ITEM_KEY)
187 return 1;
188 }
189 return 0;
190 }
191
192 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
193 struct btrfs_root *root, struct extent_buffer *parent,
194 int start_slot, int cache_only, u64 *last_ret,
195 struct btrfs_key *progress)
196 {
197 struct extent_buffer *cur;
198 struct extent_buffer *tmp;
199 u64 blocknr;
200 u64 search_start = *last_ret;
201 u64 last_block = 0;
202 u64 other;
203 u32 parent_nritems;
204 int end_slot;
205 int i;
206 int err = 0;
207 int parent_level;
208 int uptodate;
209 u32 blocksize;
210
211 if (trans->transaction != root->fs_info->running_transaction) {
212 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
213 root->fs_info->running_transaction->transid);
214 WARN_ON(1);
215 }
216 if (trans->transid != root->fs_info->generation) {
217 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
218 root->fs_info->generation);
219 WARN_ON(1);
220 }
221 parent_level = btrfs_header_level(parent);
222
223 parent_nritems = btrfs_header_nritems(parent);
224 blocksize = btrfs_level_size(root, parent_level - 1);
225 end_slot = parent_nritems;
226
227 if (parent_nritems == 1)
228 return 0;
229
230 if (root != root->fs_info->extent_root) {
231 struct btrfs_key first_key;
232 struct btrfs_key last_key;
233
234 btrfs_node_key_to_cpu(parent, &first_key, 0);
235 btrfs_node_key_to_cpu(parent, &last_key, parent_nritems - 1);
236 if (first_key.objectid != last_key.objectid)
237 return 0;
238 }
239
240 for (i = start_slot; i < end_slot; i++) {
241 int close = 1;
242
243 blocknr = btrfs_node_blockptr(parent, i);
244 if (last_block == 0)
245 last_block = blocknr;
246 if (i > 0) {
247 other = btrfs_node_blockptr(parent, i - 1);
248 close = close_blocks(blocknr, other, blocksize);
249 }
250 if (close && i < end_slot - 1) {
251 other = btrfs_node_blockptr(parent, i + 1);
252 close = close_blocks(blocknr, other, blocksize);
253 }
254 if (close) {
255 last_block = blocknr;
256 continue;
257 }
258
259 cur = btrfs_find_tree_block(root, blocknr, blocksize);
260 if (cur)
261 uptodate = btrfs_buffer_uptodate(cur);
262 else
263 uptodate = 0;
264 if (!cur || !uptodate ||
265 (parent_level != 1 && !btrfs_buffer_defrag(cur)) ||
266 (parent_level == 1 && !should_defrag_leaf(cur))) {
267 if (cache_only) {
268 free_extent_buffer(cur);
269 continue;
270 }
271 if (!cur) {
272 cur = read_tree_block(root, blocknr,
273 blocksize);
274 } else if (!uptodate) {
275 btrfs_read_buffer(cur);
276 }
277 }
278 if (search_start == 0)
279 search_start = last_block;
280
281 err = __btrfs_cow_block(trans, root, cur, parent, i,
282 &tmp, search_start,
283 min(16 * blocksize,
284 (end_slot - i) * blocksize));
285 if (err) {
286 free_extent_buffer(cur);
287 break;
288 }
289 search_start = tmp->start;
290 *last_ret = search_start;
291 if (parent_level == 1)
292 btrfs_clear_buffer_defrag(tmp);
293 free_extent_buffer(tmp);
294 }
295 return err;
296 }
297
298 /*
299 * The leaf data grows from end-to-front in the node.
300 * this returns the address of the start of the last item,
301 * which is the stop of the leaf data stack
302 */
303 static inline unsigned int leaf_data_end(struct btrfs_root *root,
304 struct extent_buffer *leaf)
305 {
306 u32 nr = btrfs_header_nritems(leaf);
307 if (nr == 0)
308 return BTRFS_LEAF_DATA_SIZE(root);
309 return btrfs_item_offset_nr(leaf, nr - 1);
310 }
311
312 /*
313 * compare two keys in a memcmp fashion
314 */
315 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
316 {
317 struct btrfs_key k1;
318
319 btrfs_disk_key_to_cpu(&k1, disk);
320
321 if (k1.objectid > k2->objectid)
322 return 1;
323 if (k1.objectid < k2->objectid)
324 return -1;
325 if (k1.type > k2->type)
326 return 1;
327 if (k1.type < k2->type)
328 return -1;
329 if (k1.offset > k2->offset)
330 return 1;
331 if (k1.offset < k2->offset)
332 return -1;
333 return 0;
334 }
335
336 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
337 int level)
338 {
339 struct extent_buffer *parent = NULL;
340 struct extent_buffer *node = path->nodes[level];
341 struct btrfs_disk_key parent_key;
342 struct btrfs_disk_key node_key;
343 int parent_slot;
344 int slot;
345 struct btrfs_key cpukey;
346 u32 nritems = btrfs_header_nritems(node);
347
348 if (path->nodes[level + 1])
349 parent = path->nodes[level + 1];
350
351 slot = path->slots[level];
352 BUG_ON(nritems == 0);
353 if (parent) {
354 parent_slot = path->slots[level + 1];
355 btrfs_node_key(parent, &parent_key, parent_slot);
356 btrfs_node_key(node, &node_key, 0);
357 BUG_ON(memcmp(&parent_key, &node_key,
358 sizeof(struct btrfs_disk_key)));
359 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
360 btrfs_header_bytenr(node));
361 }
362 BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
363 if (slot != 0) {
364 btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
365 btrfs_node_key(node, &node_key, slot);
366 BUG_ON(comp_keys(&node_key, &cpukey) <= 0);
367 }
368 if (slot < nritems - 1) {
369 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
370 btrfs_node_key(node, &node_key, slot);
371 BUG_ON(comp_keys(&node_key, &cpukey) >= 0);
372 }
373 return 0;
374 }
375
376 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
377 int level)
378 {
379 struct extent_buffer *leaf = path->nodes[level];
380 struct extent_buffer *parent = NULL;
381 int parent_slot;
382 struct btrfs_key cpukey;
383 struct btrfs_disk_key parent_key;
384 struct btrfs_disk_key leaf_key;
385 int slot = path->slots[0];
386
387 u32 nritems = btrfs_header_nritems(leaf);
388
389 if (path->nodes[level + 1])
390 parent = path->nodes[level + 1];
391
392 if (nritems == 0)
393 return 0;
394
395 if (parent) {
396 parent_slot = path->slots[level + 1];
397 btrfs_node_key(parent, &parent_key, parent_slot);
398 btrfs_item_key(leaf, &leaf_key, 0);
399
400 BUG_ON(memcmp(&parent_key, &leaf_key,
401 sizeof(struct btrfs_disk_key)));
402 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
403 btrfs_header_bytenr(leaf));
404 }
405 #if 0
406 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
407 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
408 btrfs_item_key(leaf, &leaf_key, i);
409 if (comp_keys(&leaf_key, &cpukey) >= 0) {
410 btrfs_print_leaf(root, leaf);
411 printk("slot %d offset bad key\n", i);
412 BUG_ON(1);
413 }
414 if (btrfs_item_offset_nr(leaf, i) !=
415 btrfs_item_end_nr(leaf, i + 1)) {
416 btrfs_print_leaf(root, leaf);
417 printk("slot %d offset bad\n", i);
418 BUG_ON(1);
419 }
420 if (i == 0) {
421 if (btrfs_item_offset_nr(leaf, i) +
422 btrfs_item_size_nr(leaf, i) !=
423 BTRFS_LEAF_DATA_SIZE(root)) {
424 btrfs_print_leaf(root, leaf);
425 printk("slot %d first offset bad\n", i);
426 BUG_ON(1);
427 }
428 }
429 }
430 if (nritems > 0) {
431 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
432 btrfs_print_leaf(root, leaf);
433 printk("slot %d bad size \n", nritems - 1);
434 BUG_ON(1);
435 }
436 }
437 #endif
438 if (slot != 0 && slot < nritems - 1) {
439 btrfs_item_key(leaf, &leaf_key, slot);
440 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
441 if (comp_keys(&leaf_key, &cpukey) <= 0) {
442 btrfs_print_leaf(root, leaf);
443 printk("slot %d offset bad key\n", slot);
444 BUG_ON(1);
445 }
446 if (btrfs_item_offset_nr(leaf, slot - 1) !=
447 btrfs_item_end_nr(leaf, slot)) {
448 btrfs_print_leaf(root, leaf);
449 printk("slot %d offset bad\n", slot);
450 BUG_ON(1);
451 }
452 }
453 if (slot < nritems - 1) {
454 btrfs_item_key(leaf, &leaf_key, slot);
455 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
456 BUG_ON(comp_keys(&leaf_key, &cpukey) >= 0);
457 if (btrfs_item_offset_nr(leaf, slot) !=
458 btrfs_item_end_nr(leaf, slot + 1)) {
459 btrfs_print_leaf(root, leaf);
460 printk("slot %d offset bad\n", slot);
461 BUG_ON(1);
462 }
463 }
464 BUG_ON(btrfs_item_offset_nr(leaf, 0) +
465 btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
466 return 0;
467 }
468
469 static int check_block(struct btrfs_root *root, struct btrfs_path *path,
470 int level)
471 {
472 return 0;
473 #if 0
474 struct extent_buffer *buf = path->nodes[level];
475
476 if (memcmp_extent_buffer(buf, root->fs_info->fsid,
477 (unsigned long)btrfs_header_fsid(buf),
478 BTRFS_FSID_SIZE)) {
479 printk("warning bad block %Lu\n", buf->start);
480 return 1;
481 }
482 #endif
483 if (level == 0)
484 return check_leaf(root, path, level);
485 return check_node(root, path, level);
486 }
487
488 /*
489 * search for key in the extent_buffer. The items start at offset p,
490 * and they are item_size apart. There are 'max' items in p.
491 *
492 * the slot in the array is returned via slot, and it points to
493 * the place where you would insert key if it is not found in
494 * the array.
495 *
496 * slot may point to max if the key is bigger than all of the keys
497 */
498 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
499 int item_size, struct btrfs_key *key,
500 int max, int *slot)
501 {
502 int low = 0;
503 int high = max;
504 int mid;
505 int ret;
506 struct btrfs_disk_key *tmp = NULL;
507 struct btrfs_disk_key unaligned;
508 unsigned long offset;
509 char *map_token = NULL;
510 char *kaddr = NULL;
511 unsigned long map_start = 0;
512 unsigned long map_len = 0;
513 int err;
514
515 while(low < high) {
516 mid = (low + high) / 2;
517 offset = p + mid * item_size;
518
519 if (!map_token || offset < map_start ||
520 (offset + sizeof(struct btrfs_disk_key)) >
521 map_start + map_len) {
522 if (map_token) {
523 unmap_extent_buffer(eb, map_token, KM_USER0);
524 map_token = NULL;
525 }
526 err = map_extent_buffer(eb, offset,
527 sizeof(struct btrfs_disk_key),
528 &map_token, &kaddr,
529 &map_start, &map_len, KM_USER0);
530
531 if (!err) {
532 tmp = (struct btrfs_disk_key *)(kaddr + offset -
533 map_start);
534 } else {
535 read_extent_buffer(eb, &unaligned,
536 offset, sizeof(unaligned));
537 tmp = &unaligned;
538 }
539
540 } else {
541 tmp = (struct btrfs_disk_key *)(kaddr + offset -
542 map_start);
543 }
544 ret = comp_keys(tmp, key);
545
546 if (ret < 0)
547 low = mid + 1;
548 else if (ret > 0)
549 high = mid;
550 else {
551 *slot = mid;
552 if (map_token)
553 unmap_extent_buffer(eb, map_token, KM_USER0);
554 return 0;
555 }
556 }
557 *slot = low;
558 if (map_token)
559 unmap_extent_buffer(eb, map_token, KM_USER0);
560 return 1;
561 }
562
563 /*
564 * simple bin_search frontend that does the right thing for
565 * leaves vs nodes
566 */
567 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
568 int level, int *slot)
569 {
570 if (level == 0) {
571 return generic_bin_search(eb,
572 offsetof(struct btrfs_leaf, items),
573 sizeof(struct btrfs_item),
574 key, btrfs_header_nritems(eb),
575 slot);
576 } else {
577 return generic_bin_search(eb,
578 offsetof(struct btrfs_node, ptrs),
579 sizeof(struct btrfs_key_ptr),
580 key, btrfs_header_nritems(eb),
581 slot);
582 }
583 return -1;
584 }
585
586 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
587 struct extent_buffer *parent, int slot)
588 {
589 if (slot < 0)
590 return NULL;
591 if (slot >= btrfs_header_nritems(parent))
592 return NULL;
593 return read_tree_block(root, btrfs_node_blockptr(parent, slot),
594 btrfs_level_size(root, btrfs_header_level(parent) - 1));
595 }
596
597 static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
598 *root, struct btrfs_path *path, int level)
599 {
600 struct extent_buffer *right = NULL;
601 struct extent_buffer *mid;
602 struct extent_buffer *left = NULL;
603 struct extent_buffer *parent = NULL;
604 int ret = 0;
605 int wret;
606 int pslot;
607 int orig_slot = path->slots[level];
608 int err_on_enospc = 0;
609 u64 orig_ptr;
610
611 if (level == 0)
612 return 0;
613
614 mid = path->nodes[level];
615 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
616
617 if (level < BTRFS_MAX_LEVEL - 1)
618 parent = path->nodes[level + 1];
619 pslot = path->slots[level + 1];
620
621 /*
622 * deal with the case where there is only one pointer in the root
623 * by promoting the node below to a root
624 */
625 if (!parent) {
626 struct extent_buffer *child;
627
628 if (btrfs_header_nritems(mid) != 1)
629 return 0;
630
631 /* promote the child to a root */
632 child = read_node_slot(root, mid, 0);
633 BUG_ON(!child);
634 root->node = child;
635 path->nodes[level] = NULL;
636 clean_tree_block(trans, root, mid);
637 wait_on_tree_block_writeback(root, mid);
638 /* once for the path */
639 free_extent_buffer(mid);
640 ret = btrfs_free_extent(trans, root, mid->start, mid->len, 1);
641 /* once for the root ptr */
642 free_extent_buffer(mid);
643 return ret;
644 }
645 if (btrfs_header_nritems(mid) >
646 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
647 return 0;
648
649 if (btrfs_header_nritems(mid) < 2)
650 err_on_enospc = 1;
651
652 left = read_node_slot(root, parent, pslot - 1);
653 if (left) {
654 wret = btrfs_cow_block(trans, root, left,
655 parent, pslot - 1, &left);
656 if (wret) {
657 ret = wret;
658 goto enospc;
659 }
660 }
661 right = read_node_slot(root, parent, pslot + 1);
662 if (right) {
663 wret = btrfs_cow_block(trans, root, right,
664 parent, pslot + 1, &right);
665 if (wret) {
666 ret = wret;
667 goto enospc;
668 }
669 }
670
671 /* first, try to make some room in the middle buffer */
672 if (left) {
673 orig_slot += btrfs_header_nritems(left);
674 wret = push_node_left(trans, root, left, mid);
675 if (wret < 0)
676 ret = wret;
677 if (btrfs_header_nritems(mid) < 2)
678 err_on_enospc = 1;
679 }
680
681 /*
682 * then try to empty the right most buffer into the middle
683 */
684 if (right) {
685 wret = push_node_left(trans, root, mid, right);
686 if (wret < 0 && wret != -ENOSPC)
687 ret = wret;
688 if (btrfs_header_nritems(right) == 0) {
689 u64 bytenr = right->start;
690 u32 blocksize = right->len;
691
692 clean_tree_block(trans, root, right);
693 wait_on_tree_block_writeback(root, right);
694 free_extent_buffer(right);
695 right = NULL;
696 wret = del_ptr(trans, root, path, level + 1, pslot +
697 1);
698 if (wret)
699 ret = wret;
700 wret = btrfs_free_extent(trans, root, bytenr,
701 blocksize, 1);
702 if (wret)
703 ret = wret;
704 } else {
705 struct btrfs_disk_key right_key;
706 btrfs_node_key(right, &right_key, 0);
707 btrfs_set_node_key(parent, &right_key, pslot + 1);
708 btrfs_mark_buffer_dirty(parent);
709 }
710 }
711 if (btrfs_header_nritems(mid) == 1) {
712 /*
713 * we're not allowed to leave a node with one item in the
714 * tree during a delete. A deletion from lower in the tree
715 * could try to delete the only pointer in this node.
716 * So, pull some keys from the left.
717 * There has to be a left pointer at this point because
718 * otherwise we would have pulled some pointers from the
719 * right
720 */
721 BUG_ON(!left);
722 wret = balance_node_right(trans, root, mid, left);
723 if (wret < 0) {
724 ret = wret;
725 goto enospc;
726 }
727 BUG_ON(wret == 1);
728 }
729 if (btrfs_header_nritems(mid) == 0) {
730 /* we've managed to empty the middle node, drop it */
731 u64 bytenr = mid->start;
732 u32 blocksize = mid->len;
733 clean_tree_block(trans, root, mid);
734 wait_on_tree_block_writeback(root, mid);
735 free_extent_buffer(mid);
736 mid = NULL;
737 wret = del_ptr(trans, root, path, level + 1, pslot);
738 if (wret)
739 ret = wret;
740 wret = btrfs_free_extent(trans, root, bytenr, blocksize, 1);
741 if (wret)
742 ret = wret;
743 } else {
744 /* update the parent key to reflect our changes */
745 struct btrfs_disk_key mid_key;
746 btrfs_node_key(mid, &mid_key, 0);
747 btrfs_set_node_key(parent, &mid_key, pslot);
748 btrfs_mark_buffer_dirty(parent);
749 }
750
751 /* update the path */
752 if (left) {
753 if (btrfs_header_nritems(left) > orig_slot) {
754 extent_buffer_get(left);
755 path->nodes[level] = left;
756 path->slots[level + 1] -= 1;
757 path->slots[level] = orig_slot;
758 if (mid)
759 free_extent_buffer(mid);
760 } else {
761 orig_slot -= btrfs_header_nritems(left);
762 path->slots[level] = orig_slot;
763 }
764 }
765 /* double check we haven't messed things up */
766 check_block(root, path, level);
767 if (orig_ptr !=
768 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
769 BUG();
770 enospc:
771 if (right)
772 free_extent_buffer(right);
773 if (left)
774 free_extent_buffer(left);
775 return ret;
776 }
777
778 /* returns zero if the push worked, non-zero otherwise */
779 static int push_nodes_for_insert(struct btrfs_trans_handle *trans,
780 struct btrfs_root *root,
781 struct btrfs_path *path, int level)
782 {
783 struct extent_buffer *right = NULL;
784 struct extent_buffer *mid;
785 struct extent_buffer *left = NULL;
786 struct extent_buffer *parent = NULL;
787 int ret = 0;
788 int wret;
789 int pslot;
790 int orig_slot = path->slots[level];
791 u64 orig_ptr;
792
793 if (level == 0)
794 return 1;
795
796 mid = path->nodes[level];
797 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
798
799 if (level < BTRFS_MAX_LEVEL - 1)
800 parent = path->nodes[level + 1];
801 pslot = path->slots[level + 1];
802
803 if (!parent)
804 return 1;
805
806 left = read_node_slot(root, parent, pslot - 1);
807
808 /* first, try to make some room in the middle buffer */
809 if (left) {
810 u32 left_nr;
811 left_nr = btrfs_header_nritems(left);
812 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
813 wret = 1;
814 } else {
815 ret = btrfs_cow_block(trans, root, left, parent,
816 pslot - 1, &left);
817 if (ret)
818 wret = 1;
819 else {
820 wret = push_node_left(trans, root,
821 left, mid);
822 }
823 }
824 if (wret < 0)
825 ret = wret;
826 if (wret == 0) {
827 struct btrfs_disk_key disk_key;
828 orig_slot += left_nr;
829 btrfs_node_key(mid, &disk_key, 0);
830 btrfs_set_node_key(parent, &disk_key, pslot);
831 btrfs_mark_buffer_dirty(parent);
832 if (btrfs_header_nritems(left) > orig_slot) {
833 path->nodes[level] = left;
834 path->slots[level + 1] -= 1;
835 path->slots[level] = orig_slot;
836 free_extent_buffer(mid);
837 } else {
838 orig_slot -=
839 btrfs_header_nritems(left);
840 path->slots[level] = orig_slot;
841 free_extent_buffer(left);
842 }
843 return 0;
844 }
845 free_extent_buffer(left);
846 }
847 right= read_node_slot(root, parent, pslot + 1);
848
849 /*
850 * then try to empty the right most buffer into the middle
851 */
852 if (right) {
853 u32 right_nr;
854 right_nr = btrfs_header_nritems(right);
855 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
856 wret = 1;
857 } else {
858 ret = btrfs_cow_block(trans, root, right,
859 parent, pslot + 1,
860 &right);
861 if (ret)
862 wret = 1;
863 else {
864 wret = balance_node_right(trans, root,
865 right, mid);
866 }
867 }
868 if (wret < 0)
869 ret = wret;
870 if (wret == 0) {
871 struct btrfs_disk_key disk_key;
872
873 btrfs_node_key(right, &disk_key, 0);
874 btrfs_set_node_key(parent, &disk_key, pslot + 1);
875 btrfs_mark_buffer_dirty(parent);
876
877 if (btrfs_header_nritems(mid) <= orig_slot) {
878 path->nodes[level] = right;
879 path->slots[level + 1] += 1;
880 path->slots[level] = orig_slot -
881 btrfs_header_nritems(mid);
882 free_extent_buffer(mid);
883 } else {
884 free_extent_buffer(right);
885 }
886 return 0;
887 }
888 free_extent_buffer(right);
889 }
890 return 1;
891 }
892
893 /*
894 * readahead one full node of leaves
895 */
896 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
897 int level, int slot)
898 {
899 struct extent_buffer *node;
900 u32 nritems;
901 u64 search;
902 u64 lowest_read;
903 u64 highest_read;
904 u64 nread = 0;
905 int direction = path->reada;
906 struct extent_buffer *eb;
907 u32 nr;
908 u32 blocksize;
909 u32 nscan = 0;
910
911 if (level != 1)
912 return;
913
914 if (!path->nodes[level])
915 return;
916
917 node = path->nodes[level];
918 search = btrfs_node_blockptr(node, slot);
919 blocksize = btrfs_level_size(root, level - 1);
920 eb = btrfs_find_tree_block(root, search, blocksize);
921 if (eb) {
922 free_extent_buffer(eb);
923 return;
924 }
925
926 highest_read = search;
927 lowest_read = search;
928
929 nritems = btrfs_header_nritems(node);
930 nr = slot;
931 while(1) {
932 if (direction < 0) {
933 if (nr == 0)
934 break;
935 nr--;
936 } else if (direction > 0) {
937 nr++;
938 if (nr >= nritems)
939 break;
940 }
941 search = btrfs_node_blockptr(node, nr);
942 if ((search >= lowest_read && search <= highest_read) ||
943 (search < lowest_read && lowest_read - search <= 32768) ||
944 (search > highest_read && search - highest_read <= 32768)) {
945 readahead_tree_block(root, search, blocksize);
946 nread += blocksize;
947 }
948 nscan++;
949 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
950 break;
951 if(nread > (1024 * 1024) || nscan > 128)
952 break;
953
954 if (search < lowest_read)
955 lowest_read = search;
956 if (search > highest_read)
957 highest_read = search;
958 }
959 }
960 /*
961 * look for key in the tree. path is filled in with nodes along the way
962 * if key is found, we return zero and you can find the item in the leaf
963 * level of the path (level 0)
964 *
965 * If the key isn't found, the path points to the slot where it should
966 * be inserted, and 1 is returned. If there are other errors during the
967 * search a negative error number is returned.
968 *
969 * if ins_len > 0, nodes and leaves will be split as we walk down the
970 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
971 * possible)
972 */
973 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
974 *root, struct btrfs_key *key, struct btrfs_path *p, int
975 ins_len, int cow)
976 {
977 struct extent_buffer *b;
978 u64 bytenr;
979 int slot;
980 int ret;
981 int level;
982 int should_reada = p->reada;
983 u8 lowest_level = 0;
984
985 lowest_level = p->lowest_level;
986 WARN_ON(lowest_level && ins_len);
987 WARN_ON(p->nodes[0] != NULL);
988 WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
989 again:
990 b = root->node;
991 extent_buffer_get(b);
992 while (b) {
993 level = btrfs_header_level(b);
994 if (cow) {
995 int wret;
996 wret = btrfs_cow_block(trans, root, b,
997 p->nodes[level + 1],
998 p->slots[level + 1],
999 &b);
1000 if (wret) {
1001 free_extent_buffer(b);
1002 return wret;
1003 }
1004 }
1005 BUG_ON(!cow && ins_len);
1006 if (level != btrfs_header_level(b))
1007 WARN_ON(1);
1008 level = btrfs_header_level(b);
1009 p->nodes[level] = b;
1010 ret = check_block(root, p, level);
1011 if (ret)
1012 return -1;
1013 ret = bin_search(b, key, level, &slot);
1014 if (level != 0) {
1015 if (ret && slot > 0)
1016 slot -= 1;
1017 p->slots[level] = slot;
1018 if (ins_len > 0 && btrfs_header_nritems(b) >=
1019 BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1020 int sret = split_node(trans, root, p, level);
1021 BUG_ON(sret > 0);
1022 if (sret)
1023 return sret;
1024 b = p->nodes[level];
1025 slot = p->slots[level];
1026 } else if (ins_len < 0) {
1027 int sret = balance_level(trans, root, p,
1028 level);
1029 if (sret)
1030 return sret;
1031 b = p->nodes[level];
1032 if (!b) {
1033 btrfs_release_path(NULL, p);
1034 goto again;
1035 }
1036 slot = p->slots[level];
1037 BUG_ON(btrfs_header_nritems(b) == 1);
1038 }
1039 /* this is only true while dropping a snapshot */
1040 if (level == lowest_level)
1041 break;
1042 bytenr = btrfs_node_blockptr(b, slot);
1043 if (should_reada)
1044 reada_for_search(root, p, level, slot);
1045 b = read_tree_block(root, bytenr,
1046 btrfs_level_size(root, level - 1));
1047 } else {
1048 p->slots[level] = slot;
1049 if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1050 sizeof(struct btrfs_item) + ins_len) {
1051 int sret = split_leaf(trans, root, key,
1052 p, ins_len);
1053 BUG_ON(sret > 0);
1054 if (sret)
1055 return sret;
1056 }
1057 return ret;
1058 }
1059 }
1060 return 1;
1061 }
1062
1063 /*
1064 * adjust the pointers going up the tree, starting at level
1065 * making sure the right key of each node is points to 'key'.
1066 * This is used after shifting pointers to the left, so it stops
1067 * fixing up pointers when a given leaf/node is not in slot 0 of the
1068 * higher levels
1069 *
1070 * If this fails to write a tree block, it returns -1, but continues
1071 * fixing up the blocks in ram so the tree is consistent.
1072 */
1073 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1074 struct btrfs_root *root, struct btrfs_path *path,
1075 struct btrfs_disk_key *key, int level)
1076 {
1077 int i;
1078 int ret = 0;
1079 struct extent_buffer *t;
1080
1081 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1082 int tslot = path->slots[i];
1083 if (!path->nodes[i])
1084 break;
1085 t = path->nodes[i];
1086 btrfs_set_node_key(t, key, tslot);
1087 btrfs_mark_buffer_dirty(path->nodes[i]);
1088 if (tslot != 0)
1089 break;
1090 }
1091 return ret;
1092 }
1093
1094 /*
1095 * try to push data from one node into the next node left in the
1096 * tree.
1097 *
1098 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1099 * error, and > 0 if there was no room in the left hand block.
1100 */
1101 static int push_node_left(struct btrfs_trans_handle *trans, struct btrfs_root
1102 *root, struct extent_buffer *dst,
1103 struct extent_buffer *src)
1104 {
1105 int push_items = 0;
1106 int src_nritems;
1107 int dst_nritems;
1108 int ret = 0;
1109
1110 src_nritems = btrfs_header_nritems(src);
1111 dst_nritems = btrfs_header_nritems(dst);
1112 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1113
1114 if (push_items <= 0) {
1115 return 1;
1116 }
1117
1118 if (src_nritems < push_items)
1119 push_items = src_nritems;
1120
1121 copy_extent_buffer(dst, src,
1122 btrfs_node_key_ptr_offset(dst_nritems),
1123 btrfs_node_key_ptr_offset(0),
1124 push_items * sizeof(struct btrfs_key_ptr));
1125
1126 if (push_items < src_nritems) {
1127 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1128 btrfs_node_key_ptr_offset(push_items),
1129 (src_nritems - push_items) *
1130 sizeof(struct btrfs_key_ptr));
1131 }
1132 btrfs_set_header_nritems(src, src_nritems - push_items);
1133 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1134 btrfs_mark_buffer_dirty(src);
1135 btrfs_mark_buffer_dirty(dst);
1136 return ret;
1137 }
1138
1139 /*
1140 * try to push data from one node into the next node right in the
1141 * tree.
1142 *
1143 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1144 * error, and > 0 if there was no room in the right hand block.
1145 *
1146 * this will only push up to 1/2 the contents of the left node over
1147 */
1148 static int balance_node_right(struct btrfs_trans_handle *trans,
1149 struct btrfs_root *root,
1150 struct extent_buffer *dst,
1151 struct extent_buffer *src)
1152 {
1153 int push_items = 0;
1154 int max_push;
1155 int src_nritems;
1156 int dst_nritems;
1157 int ret = 0;
1158
1159 src_nritems = btrfs_header_nritems(src);
1160 dst_nritems = btrfs_header_nritems(dst);
1161 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1162 if (push_items <= 0)
1163 return 1;
1164
1165 max_push = src_nritems / 2 + 1;
1166 /* don't try to empty the node */
1167 if (max_push >= src_nritems)
1168 return 1;
1169
1170 if (max_push < push_items)
1171 push_items = max_push;
1172
1173 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1174 btrfs_node_key_ptr_offset(0),
1175 (dst_nritems) *
1176 sizeof(struct btrfs_key_ptr));
1177
1178 copy_extent_buffer(dst, src,
1179 btrfs_node_key_ptr_offset(0),
1180 btrfs_node_key_ptr_offset(src_nritems - push_items),
1181 push_items * sizeof(struct btrfs_key_ptr));
1182
1183 btrfs_set_header_nritems(src, src_nritems - push_items);
1184 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1185
1186 btrfs_mark_buffer_dirty(src);
1187 btrfs_mark_buffer_dirty(dst);
1188 return ret;
1189 }
1190
1191 /*
1192 * helper function to insert a new root level in the tree.
1193 * A new node is allocated, and a single item is inserted to
1194 * point to the existing root
1195 *
1196 * returns zero on success or < 0 on failure.
1197 */
1198 static int insert_new_root(struct btrfs_trans_handle *trans,
1199 struct btrfs_root *root,
1200 struct btrfs_path *path, int level)
1201 {
1202 struct extent_buffer *lower;
1203 struct extent_buffer *c;
1204 struct btrfs_disk_key lower_key;
1205
1206 BUG_ON(path->nodes[level]);
1207 BUG_ON(path->nodes[level-1] != root->node);
1208
1209 c = btrfs_alloc_free_block(trans, root, root->nodesize,
1210 root->node->start, 0);
1211 if (IS_ERR(c))
1212 return PTR_ERR(c);
1213 memset_extent_buffer(c, 0, 0, root->nodesize);
1214 btrfs_set_header_nritems(c, 1);
1215 btrfs_set_header_level(c, level);
1216 btrfs_set_header_bytenr(c, c->start);
1217 btrfs_set_header_generation(c, trans->transid);
1218 btrfs_set_header_owner(c, root->root_key.objectid);
1219 lower = path->nodes[level-1];
1220
1221 write_extent_buffer(c, root->fs_info->fsid,
1222 (unsigned long)btrfs_header_fsid(c),
1223 BTRFS_FSID_SIZE);
1224 if (level == 1)
1225 btrfs_item_key(lower, &lower_key, 0);
1226 else
1227 btrfs_node_key(lower, &lower_key, 0);
1228 btrfs_set_node_key(c, &lower_key, 0);
1229 btrfs_set_node_blockptr(c, 0, lower->start);
1230
1231 btrfs_mark_buffer_dirty(c);
1232
1233 /* the super has an extra ref to root->node */
1234 free_extent_buffer(root->node);
1235 root->node = c;
1236 extent_buffer_get(c);
1237 path->nodes[level] = c;
1238 path->slots[level] = 0;
1239 return 0;
1240 }
1241
1242 /*
1243 * worker function to insert a single pointer in a node.
1244 * the node should have enough room for the pointer already
1245 *
1246 * slot and level indicate where you want the key to go, and
1247 * blocknr is the block the key points to.
1248 *
1249 * returns zero on success and < 0 on any error
1250 */
1251 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1252 *root, struct btrfs_path *path, struct btrfs_disk_key
1253 *key, u64 bytenr, int slot, int level)
1254 {
1255 struct extent_buffer *lower;
1256 int nritems;
1257
1258 BUG_ON(!path->nodes[level]);
1259 lower = path->nodes[level];
1260 nritems = btrfs_header_nritems(lower);
1261 if (slot > nritems)
1262 BUG();
1263 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1264 BUG();
1265 if (slot != nritems) {
1266 memmove_extent_buffer(lower,
1267 btrfs_node_key_ptr_offset(slot + 1),
1268 btrfs_node_key_ptr_offset(slot),
1269 (nritems - slot) * sizeof(struct btrfs_key_ptr));
1270 }
1271 btrfs_set_node_key(lower, key, slot);
1272 btrfs_set_node_blockptr(lower, slot, bytenr);
1273 btrfs_set_header_nritems(lower, nritems + 1);
1274 btrfs_mark_buffer_dirty(lower);
1275 return 0;
1276 }
1277
1278 /*
1279 * split the node at the specified level in path in two.
1280 * The path is corrected to point to the appropriate node after the split
1281 *
1282 * Before splitting this tries to make some room in the node by pushing
1283 * left and right, if either one works, it returns right away.
1284 *
1285 * returns 0 on success and < 0 on failure
1286 */
1287 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1288 *root, struct btrfs_path *path, int level)
1289 {
1290 struct extent_buffer *c;
1291 struct extent_buffer *split;
1292 struct btrfs_disk_key disk_key;
1293 int mid;
1294 int ret;
1295 int wret;
1296 u32 c_nritems;
1297
1298 c = path->nodes[level];
1299 if (c == root->node) {
1300 /* trying to split the root, lets make a new one */
1301 ret = insert_new_root(trans, root, path, level + 1);
1302 if (ret)
1303 return ret;
1304 } else {
1305 ret = push_nodes_for_insert(trans, root, path, level);
1306 c = path->nodes[level];
1307 if (!ret && btrfs_header_nritems(c) <
1308 BTRFS_NODEPTRS_PER_BLOCK(root) - 1)
1309 return 0;
1310 if (ret < 0)
1311 return ret;
1312 }
1313
1314 c_nritems = btrfs_header_nritems(c);
1315 split = btrfs_alloc_free_block(trans, root, root->nodesize,
1316 c->start, 0);
1317 if (IS_ERR(split))
1318 return PTR_ERR(split);
1319
1320 btrfs_set_header_flags(split, btrfs_header_flags(c));
1321 btrfs_set_header_level(split, btrfs_header_level(c));
1322 btrfs_set_header_bytenr(split, split->start);
1323 btrfs_set_header_generation(split, trans->transid);
1324 btrfs_set_header_owner(split, root->root_key.objectid);
1325 write_extent_buffer(split, root->fs_info->fsid,
1326 (unsigned long)btrfs_header_fsid(split),
1327 BTRFS_FSID_SIZE);
1328
1329 mid = (c_nritems + 1) / 2;
1330
1331 copy_extent_buffer(split, c,
1332 btrfs_node_key_ptr_offset(0),
1333 btrfs_node_key_ptr_offset(mid),
1334 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1335 btrfs_set_header_nritems(split, c_nritems - mid);
1336 btrfs_set_header_nritems(c, mid);
1337 ret = 0;
1338
1339 btrfs_mark_buffer_dirty(c);
1340 btrfs_mark_buffer_dirty(split);
1341
1342 btrfs_node_key(split, &disk_key, 0);
1343 wret = insert_ptr(trans, root, path, &disk_key, split->start,
1344 path->slots[level + 1] + 1,
1345 level + 1);
1346 if (wret)
1347 ret = wret;
1348
1349 if (path->slots[level] >= mid) {
1350 path->slots[level] -= mid;
1351 free_extent_buffer(c);
1352 path->nodes[level] = split;
1353 path->slots[level + 1] += 1;
1354 } else {
1355 free_extent_buffer(split);
1356 }
1357 return ret;
1358 }
1359
1360 /*
1361 * how many bytes are required to store the items in a leaf. start
1362 * and nr indicate which items in the leaf to check. This totals up the
1363 * space used both by the item structs and the item data
1364 */
1365 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1366 {
1367 int data_len;
1368 int nritems = btrfs_header_nritems(l);
1369 int end = min(nritems, start + nr) - 1;
1370
1371 if (!nr)
1372 return 0;
1373 data_len = btrfs_item_end_nr(l, start);
1374 data_len = data_len - btrfs_item_offset_nr(l, end);
1375 data_len += sizeof(struct btrfs_item) * nr;
1376 WARN_ON(data_len < 0);
1377 return data_len;
1378 }
1379
1380 /*
1381 * The space between the end of the leaf items and
1382 * the start of the leaf data. IOW, how much room
1383 * the leaf has left for both items and data
1384 */
1385 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1386 {
1387 int nritems = btrfs_header_nritems(leaf);
1388 int ret;
1389 ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1390 if (ret < 0) {
1391 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1392 ret, BTRFS_LEAF_DATA_SIZE(root),
1393 leaf_space_used(leaf, 0, nritems), nritems);
1394 }
1395 return ret;
1396 }
1397
1398 /*
1399 * push some data in the path leaf to the right, trying to free up at
1400 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1401 *
1402 * returns 1 if the push failed because the other node didn't have enough
1403 * room, 0 if everything worked out and < 0 if there were major errors.
1404 */
1405 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1406 *root, struct btrfs_path *path, int data_size)
1407 {
1408 struct extent_buffer *left = path->nodes[0];
1409 struct extent_buffer *right;
1410 struct extent_buffer *upper;
1411 struct btrfs_disk_key disk_key;
1412 int slot;
1413 int i;
1414 int free_space;
1415 int push_space = 0;
1416 int push_items = 0;
1417 struct btrfs_item *item;
1418 u32 left_nritems;
1419 u32 right_nritems;
1420 u32 data_end;
1421 u32 this_item_size;
1422 int ret;
1423
1424 slot = path->slots[1];
1425 if (!path->nodes[1]) {
1426 return 1;
1427 }
1428 upper = path->nodes[1];
1429 if (slot >= btrfs_header_nritems(upper) - 1)
1430 return 1;
1431
1432 right = read_tree_block(root, btrfs_node_blockptr(upper, slot + 1),
1433 root->leafsize);
1434 free_space = btrfs_leaf_free_space(root, right);
1435 if (free_space < data_size + sizeof(struct btrfs_item)) {
1436 free_extent_buffer(right);
1437 return 1;
1438 }
1439
1440 /* cow and double check */
1441 ret = btrfs_cow_block(trans, root, right, upper,
1442 slot + 1, &right);
1443 if (ret) {
1444 free_extent_buffer(right);
1445 return 1;
1446 }
1447 free_space = btrfs_leaf_free_space(root, right);
1448 if (free_space < data_size + sizeof(struct btrfs_item)) {
1449 free_extent_buffer(right);
1450 return 1;
1451 }
1452
1453 left_nritems = btrfs_header_nritems(left);
1454 if (left_nritems == 0) {
1455 free_extent_buffer(right);
1456 return 1;
1457 }
1458
1459 for (i = left_nritems - 1; i >= 1; i--) {
1460 item = btrfs_item_nr(left, i);
1461
1462 if (path->slots[0] == i)
1463 push_space += data_size + sizeof(*item);
1464
1465 if (!left->map_token) {
1466 map_extent_buffer(left, (unsigned long)item,
1467 sizeof(struct btrfs_item),
1468 &left->map_token, &left->kaddr,
1469 &left->map_start, &left->map_len,
1470 KM_USER1);
1471 }
1472
1473 this_item_size = btrfs_item_size(left, item);
1474 if (this_item_size + sizeof(*item) + push_space > free_space)
1475 break;
1476 push_items++;
1477 push_space += this_item_size + sizeof(*item);
1478 }
1479 if (left->map_token) {
1480 unmap_extent_buffer(left, left->map_token, KM_USER1);
1481 left->map_token = NULL;
1482 }
1483
1484 if (push_items == 0) {
1485 free_extent_buffer(right);
1486 return 1;
1487 }
1488
1489 if (push_items == left_nritems)
1490 WARN_ON(1);
1491
1492 /* push left to right */
1493 right_nritems = btrfs_header_nritems(right);
1494 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1495 push_space -= leaf_data_end(root, left);
1496
1497 /* make room in the right data area */
1498 data_end = leaf_data_end(root, right);
1499 memmove_extent_buffer(right,
1500 btrfs_leaf_data(right) + data_end - push_space,
1501 btrfs_leaf_data(right) + data_end,
1502 BTRFS_LEAF_DATA_SIZE(root) - data_end);
1503
1504 /* copy from the left data area */
1505 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1506 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1507 btrfs_leaf_data(left) + leaf_data_end(root, left),
1508 push_space);
1509
1510 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1511 btrfs_item_nr_offset(0),
1512 right_nritems * sizeof(struct btrfs_item));
1513
1514 /* copy the items from left to right */
1515 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1516 btrfs_item_nr_offset(left_nritems - push_items),
1517 push_items * sizeof(struct btrfs_item));
1518
1519 /* update the item pointers */
1520 right_nritems += push_items;
1521 btrfs_set_header_nritems(right, right_nritems);
1522 push_space = BTRFS_LEAF_DATA_SIZE(root);
1523
1524 for (i = 0; i < right_nritems; i++) {
1525 item = btrfs_item_nr(right, i);
1526 if (!right->map_token) {
1527 map_extent_buffer(right, (unsigned long)item,
1528 sizeof(struct btrfs_item),
1529 &right->map_token, &right->kaddr,
1530 &right->map_start, &right->map_len,
1531 KM_USER1);
1532 }
1533 push_space -= btrfs_item_size(right, item);
1534 btrfs_set_item_offset(right, item, push_space);
1535 }
1536
1537 if (right->map_token) {
1538 unmap_extent_buffer(right, right->map_token, KM_USER1);
1539 right->map_token = NULL;
1540 }
1541 left_nritems -= push_items;
1542 btrfs_set_header_nritems(left, left_nritems);
1543
1544 btrfs_mark_buffer_dirty(left);
1545 btrfs_mark_buffer_dirty(right);
1546
1547 btrfs_item_key(right, &disk_key, 0);
1548 btrfs_set_node_key(upper, &disk_key, slot + 1);
1549 btrfs_mark_buffer_dirty(upper);
1550
1551 /* then fixup the leaf pointer in the path */
1552 if (path->slots[0] >= left_nritems) {
1553 path->slots[0] -= left_nritems;
1554 free_extent_buffer(path->nodes[0]);
1555 path->nodes[0] = right;
1556 path->slots[1] += 1;
1557 } else {
1558 free_extent_buffer(right);
1559 }
1560 return 0;
1561 }
1562 /*
1563 * push some data in the path leaf to the left, trying to free up at
1564 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1565 */
1566 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1567 *root, struct btrfs_path *path, int data_size)
1568 {
1569 struct btrfs_disk_key disk_key;
1570 struct extent_buffer *right = path->nodes[0];
1571 struct extent_buffer *left;
1572 int slot;
1573 int i;
1574 int free_space;
1575 int push_space = 0;
1576 int push_items = 0;
1577 struct btrfs_item *item;
1578 u32 old_left_nritems;
1579 u32 right_nritems;
1580 int ret = 0;
1581 int wret;
1582 u32 this_item_size;
1583 u32 old_left_item_size;
1584
1585 slot = path->slots[1];
1586 if (slot == 0)
1587 return 1;
1588 if (!path->nodes[1])
1589 return 1;
1590
1591 left = read_tree_block(root, btrfs_node_blockptr(path->nodes[1],
1592 slot - 1), root->leafsize);
1593 free_space = btrfs_leaf_free_space(root, left);
1594 if (free_space < data_size + sizeof(struct btrfs_item)) {
1595 free_extent_buffer(left);
1596 return 1;
1597 }
1598
1599 /* cow and double check */
1600 ret = btrfs_cow_block(trans, root, left,
1601 path->nodes[1], slot - 1, &left);
1602 if (ret) {
1603 /* we hit -ENOSPC, but it isn't fatal here */
1604 free_extent_buffer(left);
1605 return 1;
1606 }
1607 free_space = btrfs_leaf_free_space(root, left);
1608 if (free_space < data_size + sizeof(struct btrfs_item)) {
1609 free_extent_buffer(left);
1610 return 1;
1611 }
1612
1613 right_nritems = btrfs_header_nritems(right);
1614 if (right_nritems == 0) {
1615 free_extent_buffer(left);
1616 return 1;
1617 }
1618
1619 for (i = 0; i < right_nritems - 1; i++) {
1620 item = btrfs_item_nr(right, i);
1621 if (!right->map_token) {
1622 map_extent_buffer(right, (unsigned long)item,
1623 sizeof(struct btrfs_item),
1624 &right->map_token, &right->kaddr,
1625 &right->map_start, &right->map_len,
1626 KM_USER1);
1627 }
1628
1629 if (path->slots[0] == i)
1630 push_space += data_size + sizeof(*item);
1631
1632 this_item_size = btrfs_item_size(right, item);
1633 if (this_item_size + sizeof(*item) + push_space > free_space)
1634 break;
1635
1636 push_items++;
1637 push_space += this_item_size + sizeof(*item);
1638 }
1639
1640 if (right->map_token) {
1641 unmap_extent_buffer(right, right->map_token, KM_USER1);
1642 right->map_token = NULL;
1643 }
1644
1645 if (push_items == 0) {
1646 free_extent_buffer(left);
1647 return 1;
1648 }
1649 if (push_items == btrfs_header_nritems(right))
1650 WARN_ON(1);
1651
1652 /* push data from right to left */
1653 copy_extent_buffer(left, right,
1654 btrfs_item_nr_offset(btrfs_header_nritems(left)),
1655 btrfs_item_nr_offset(0),
1656 push_items * sizeof(struct btrfs_item));
1657
1658 push_space = BTRFS_LEAF_DATA_SIZE(root) -
1659 btrfs_item_offset_nr(right, push_items -1);
1660
1661 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
1662 leaf_data_end(root, left) - push_space,
1663 btrfs_leaf_data(right) +
1664 btrfs_item_offset_nr(right, push_items - 1),
1665 push_space);
1666 old_left_nritems = btrfs_header_nritems(left);
1667 BUG_ON(old_left_nritems < 0);
1668
1669 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
1670 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1671 u32 ioff;
1672
1673 item = btrfs_item_nr(left, i);
1674 if (!left->map_token) {
1675 map_extent_buffer(left, (unsigned long)item,
1676 sizeof(struct btrfs_item),
1677 &left->map_token, &left->kaddr,
1678 &left->map_start, &left->map_len,
1679 KM_USER1);
1680 }
1681
1682 ioff = btrfs_item_offset(left, item);
1683 btrfs_set_item_offset(left, item,
1684 ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
1685 }
1686 btrfs_set_header_nritems(left, old_left_nritems + push_items);
1687 if (left->map_token) {
1688 unmap_extent_buffer(left, left->map_token, KM_USER1);
1689 left->map_token = NULL;
1690 }
1691
1692 /* fixup right node */
1693 push_space = btrfs_item_offset_nr(right, push_items - 1) -
1694 leaf_data_end(root, right);
1695 memmove_extent_buffer(right, btrfs_leaf_data(right) +
1696 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1697 btrfs_leaf_data(right) +
1698 leaf_data_end(root, right), push_space);
1699
1700 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
1701 btrfs_item_nr_offset(push_items),
1702 (btrfs_header_nritems(right) - push_items) *
1703 sizeof(struct btrfs_item));
1704
1705 right_nritems = btrfs_header_nritems(right) - push_items;
1706 btrfs_set_header_nritems(right, right_nritems);
1707 push_space = BTRFS_LEAF_DATA_SIZE(root);
1708
1709 for (i = 0; i < right_nritems; i++) {
1710 item = btrfs_item_nr(right, i);
1711
1712 if (!right->map_token) {
1713 map_extent_buffer(right, (unsigned long)item,
1714 sizeof(struct btrfs_item),
1715 &right->map_token, &right->kaddr,
1716 &right->map_start, &right->map_len,
1717 KM_USER1);
1718 }
1719
1720 push_space = push_space - btrfs_item_size(right, item);
1721 btrfs_set_item_offset(right, item, push_space);
1722 }
1723 if (right->map_token) {
1724 unmap_extent_buffer(right, right->map_token, KM_USER1);
1725 right->map_token = NULL;
1726 }
1727
1728 btrfs_mark_buffer_dirty(left);
1729 btrfs_mark_buffer_dirty(right);
1730
1731 btrfs_item_key(right, &disk_key, 0);
1732 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1733 if (wret)
1734 ret = wret;
1735
1736 /* then fixup the leaf pointer in the path */
1737 if (path->slots[0] < push_items) {
1738 path->slots[0] += old_left_nritems;
1739 free_extent_buffer(path->nodes[0]);
1740 path->nodes[0] = left;
1741 path->slots[1] -= 1;
1742 } else {
1743 free_extent_buffer(left);
1744 path->slots[0] -= push_items;
1745 }
1746 BUG_ON(path->slots[0] < 0);
1747 return ret;
1748 }
1749
1750 /*
1751 * split the path's leaf in two, making sure there is at least data_size
1752 * available for the resulting leaf level of the path.
1753 *
1754 * returns 0 if all went well and < 0 on failure.
1755 */
1756 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1757 *root, struct btrfs_key *ins_key,
1758 struct btrfs_path *path, int data_size)
1759 {
1760 struct extent_buffer *l;
1761 u32 nritems;
1762 int mid;
1763 int slot;
1764 struct extent_buffer *right;
1765 int space_needed = data_size + sizeof(struct btrfs_item);
1766 int data_copy_size;
1767 int rt_data_off;
1768 int i;
1769 int ret = 0;
1770 int wret;
1771 int double_split = 0;
1772 struct btrfs_disk_key disk_key;
1773
1774 /* first try to make some room by pushing left and right */
1775 wret = push_leaf_left(trans, root, path, data_size);
1776 if (wret < 0) {
1777 return wret;
1778 }
1779 if (wret) {
1780 wret = push_leaf_right(trans, root, path, data_size);
1781 if (wret < 0)
1782 return wret;
1783 }
1784 l = path->nodes[0];
1785
1786 /* did the pushes work? */
1787 if (btrfs_leaf_free_space(root, l) >=
1788 sizeof(struct btrfs_item) + data_size) {
1789 return 0;
1790 }
1791
1792 if (!path->nodes[1]) {
1793 ret = insert_new_root(trans, root, path, 1);
1794 if (ret)
1795 return ret;
1796 }
1797 slot = path->slots[0];
1798 nritems = btrfs_header_nritems(l);
1799 mid = (nritems + 1)/ 2;
1800
1801 right = btrfs_alloc_free_block(trans, root, root->leafsize,
1802 l->start, 0);
1803 if (IS_ERR(right))
1804 return PTR_ERR(right);
1805
1806 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
1807 btrfs_set_header_bytenr(right, right->start);
1808 btrfs_set_header_generation(right, trans->transid);
1809 btrfs_set_header_owner(right, root->root_key.objectid);
1810 btrfs_set_header_level(right, 0);
1811 write_extent_buffer(right, root->fs_info->fsid,
1812 (unsigned long)btrfs_header_fsid(right),
1813 BTRFS_FSID_SIZE);
1814
1815 if (mid <= slot) {
1816 if (nritems == 1 ||
1817 leaf_space_used(l, mid, nritems - mid) + space_needed >
1818 BTRFS_LEAF_DATA_SIZE(root)) {
1819 if (slot >= nritems) {
1820 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1821 btrfs_set_header_nritems(right, 0);
1822 wret = insert_ptr(trans, root, path,
1823 &disk_key, right->start,
1824 path->slots[1] + 1, 1);
1825 if (wret)
1826 ret = wret;
1827 free_extent_buffer(path->nodes[0]);
1828 path->nodes[0] = right;
1829 path->slots[0] = 0;
1830 path->slots[1] += 1;
1831 return ret;
1832 }
1833 mid = slot;
1834 if (mid != nritems &&
1835 leaf_space_used(l, mid, nritems - mid) +
1836 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
1837 double_split = 1;
1838 }
1839 }
1840 } else {
1841 if (leaf_space_used(l, 0, mid + 1) + space_needed >
1842 BTRFS_LEAF_DATA_SIZE(root)) {
1843 if (slot == 0) {
1844 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1845 btrfs_set_header_nritems(right, 0);
1846 wret = insert_ptr(trans, root, path,
1847 &disk_key,
1848 right->start,
1849 path->slots[1], 1);
1850 if (wret)
1851 ret = wret;
1852 free_extent_buffer(path->nodes[0]);
1853 path->nodes[0] = right;
1854 path->slots[0] = 0;
1855 if (path->slots[1] == 0) {
1856 wret = fixup_low_keys(trans, root,
1857 path, &disk_key, 1);
1858 if (wret)
1859 ret = wret;
1860 }
1861 return ret;
1862 }
1863 mid = slot;
1864 double_split = 1;
1865 }
1866 }
1867 nritems = nritems - mid;
1868 btrfs_set_header_nritems(right, nritems);
1869 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
1870
1871 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
1872 btrfs_item_nr_offset(mid),
1873 nritems * sizeof(struct btrfs_item));
1874
1875 copy_extent_buffer(right, l,
1876 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
1877 data_copy_size, btrfs_leaf_data(l) +
1878 leaf_data_end(root, l), data_copy_size);
1879
1880 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
1881 btrfs_item_end_nr(l, mid);
1882
1883 for (i = 0; i < nritems; i++) {
1884 struct btrfs_item *item = btrfs_item_nr(right, i);
1885 u32 ioff;
1886
1887 if (!right->map_token) {
1888 map_extent_buffer(right, (unsigned long)item,
1889 sizeof(struct btrfs_item),
1890 &right->map_token, &right->kaddr,
1891 &right->map_start, &right->map_len,
1892 KM_USER1);
1893 }
1894
1895 ioff = btrfs_item_offset(right, item);
1896 btrfs_set_item_offset(right, item, ioff + rt_data_off);
1897 }
1898
1899 if (right->map_token) {
1900 unmap_extent_buffer(right, right->map_token, KM_USER1);
1901 right->map_token = NULL;
1902 }
1903
1904 btrfs_set_header_nritems(l, mid);
1905 ret = 0;
1906 btrfs_item_key(right, &disk_key, 0);
1907 wret = insert_ptr(trans, root, path, &disk_key, right->start,
1908 path->slots[1] + 1, 1);
1909 if (wret)
1910 ret = wret;
1911
1912 btrfs_mark_buffer_dirty(right);
1913 btrfs_mark_buffer_dirty(l);
1914 BUG_ON(path->slots[0] != slot);
1915
1916 if (mid <= slot) {
1917 free_extent_buffer(path->nodes[0]);
1918 path->nodes[0] = right;
1919 path->slots[0] -= mid;
1920 path->slots[1] += 1;
1921 } else
1922 free_extent_buffer(right);
1923
1924 BUG_ON(path->slots[0] < 0);
1925
1926 if (!double_split) {
1927 return ret;
1928 }
1929
1930 right = btrfs_alloc_free_block(trans, root, root->leafsize,
1931 l->start, 0);
1932 if (IS_ERR(right))
1933 return PTR_ERR(right);
1934
1935 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
1936 btrfs_set_header_bytenr(right, right->start);
1937 btrfs_set_header_generation(right, trans->transid);
1938 btrfs_set_header_owner(right, root->root_key.objectid);
1939 btrfs_set_header_level(right, 0);
1940 write_extent_buffer(right, root->fs_info->fsid,
1941 (unsigned long)btrfs_header_fsid(right),
1942 BTRFS_FSID_SIZE);
1943
1944 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1945 btrfs_set_header_nritems(right, 0);
1946 wret = insert_ptr(trans, root, path,
1947 &disk_key, right->start,
1948 path->slots[1], 1);
1949 if (wret)
1950 ret = wret;
1951 if (path->slots[1] == 0) {
1952 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1953 if (wret)
1954 ret = wret;
1955 }
1956 free_extent_buffer(path->nodes[0]);
1957 path->nodes[0] = right;
1958 path->slots[0] = 0;
1959 return ret;
1960 }
1961
1962 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
1963 struct btrfs_root *root,
1964 struct btrfs_path *path,
1965 u32 new_size)
1966 {
1967 int ret = 0;
1968 int slot;
1969 int slot_orig;
1970 struct extent_buffer *leaf;
1971 struct btrfs_item *item;
1972 u32 nritems;
1973 unsigned int data_end;
1974 unsigned int old_data_start;
1975 unsigned int old_size;
1976 unsigned int size_diff;
1977 int i;
1978
1979 slot_orig = path->slots[0];
1980 leaf = path->nodes[0];
1981
1982 nritems = btrfs_header_nritems(leaf);
1983 data_end = leaf_data_end(root, leaf);
1984
1985 slot = path->slots[0];
1986 old_data_start = btrfs_item_offset_nr(leaf, slot);
1987 old_size = btrfs_item_size_nr(leaf, slot);
1988 BUG_ON(old_size <= new_size);
1989 size_diff = old_size - new_size;
1990
1991 BUG_ON(slot < 0);
1992 BUG_ON(slot >= nritems);
1993
1994 /*
1995 * item0..itemN ... dataN.offset..dataN.size .. data0.size
1996 */
1997 /* first correct the data pointers */
1998 for (i = slot; i < nritems; i++) {
1999 u32 ioff;
2000 item = btrfs_item_nr(leaf, i);
2001
2002 if (!leaf->map_token) {
2003 map_extent_buffer(leaf, (unsigned long)item,
2004 sizeof(struct btrfs_item),
2005 &leaf->map_token, &leaf->kaddr,
2006 &leaf->map_start, &leaf->map_len,
2007 KM_USER1);
2008 }
2009
2010 ioff = btrfs_item_offset(leaf, item);
2011 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2012 }
2013
2014 if (leaf->map_token) {
2015 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2016 leaf->map_token = NULL;
2017 }
2018
2019 /* shift the data */
2020 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2021 data_end + size_diff, btrfs_leaf_data(leaf) +
2022 data_end, old_data_start + new_size - data_end);
2023
2024 item = btrfs_item_nr(leaf, slot);
2025 btrfs_set_item_size(leaf, item, new_size);
2026 btrfs_mark_buffer_dirty(leaf);
2027
2028 ret = 0;
2029 if (btrfs_leaf_free_space(root, leaf) < 0) {
2030 btrfs_print_leaf(root, leaf);
2031 BUG();
2032 }
2033 return ret;
2034 }
2035
2036 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2037 struct btrfs_root *root, struct btrfs_path *path,
2038 u32 data_size)
2039 {
2040 int ret = 0;
2041 int slot;
2042 int slot_orig;
2043 struct extent_buffer *leaf;
2044 struct btrfs_item *item;
2045 u32 nritems;
2046 unsigned int data_end;
2047 unsigned int old_data;
2048 unsigned int old_size;
2049 int i;
2050
2051 slot_orig = path->slots[0];
2052 leaf = path->nodes[0];
2053
2054 nritems = btrfs_header_nritems(leaf);
2055 data_end = leaf_data_end(root, leaf);
2056
2057 if (btrfs_leaf_free_space(root, leaf) < data_size) {
2058 btrfs_print_leaf(root, leaf);
2059 BUG();
2060 }
2061 slot = path->slots[0];
2062 old_data = btrfs_item_end_nr(leaf, slot);
2063
2064 BUG_ON(slot < 0);
2065 if (slot >= nritems) {
2066 btrfs_print_leaf(root, leaf);
2067 printk("slot %d too large, nritems %d\n", slot, nritems);
2068 BUG_ON(1);
2069 }
2070
2071 /*
2072 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2073 */
2074 /* first correct the data pointers */
2075 for (i = slot; i < nritems; i++) {
2076 u32 ioff;
2077 item = btrfs_item_nr(leaf, i);
2078
2079 if (!leaf->map_token) {
2080 map_extent_buffer(leaf, (unsigned long)item,
2081 sizeof(struct btrfs_item),
2082 &leaf->map_token, &leaf->kaddr,
2083 &leaf->map_start, &leaf->map_len,
2084 KM_USER1);
2085 }
2086 ioff = btrfs_item_offset(leaf, item);
2087 btrfs_set_item_offset(leaf, item, ioff - data_size);
2088 }
2089
2090 if (leaf->map_token) {
2091 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2092 leaf->map_token = NULL;
2093 }
2094
2095 /* shift the data */
2096 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2097 data_end - data_size, btrfs_leaf_data(leaf) +
2098 data_end, old_data - data_end);
2099
2100 data_end = old_data;
2101 old_size = btrfs_item_size_nr(leaf, slot);
2102 item = btrfs_item_nr(leaf, slot);
2103 btrfs_set_item_size(leaf, item, old_size + data_size);
2104 btrfs_mark_buffer_dirty(leaf);
2105
2106 ret = 0;
2107 if (btrfs_leaf_free_space(root, leaf) < 0) {
2108 btrfs_print_leaf(root, leaf);
2109 BUG();
2110 }
2111 return ret;
2112 }
2113
2114 /*
2115 * Given a key and some data, insert an item into the tree.
2116 * This does all the path init required, making room in the tree if needed.
2117 */
2118 int btrfs_insert_empty_item(struct btrfs_trans_handle *trans,
2119 struct btrfs_root *root,
2120 struct btrfs_path *path,
2121 struct btrfs_key *cpu_key, u32 data_size)
2122 {
2123 struct extent_buffer *leaf;
2124 struct btrfs_item *item;
2125 int ret = 0;
2126 int slot;
2127 int slot_orig;
2128 u32 nritems;
2129 unsigned int data_end;
2130 struct btrfs_disk_key disk_key;
2131
2132 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2133
2134 /* create a root if there isn't one */
2135 if (!root->node)
2136 BUG();
2137
2138 ret = btrfs_search_slot(trans, root, cpu_key, path, data_size, 1);
2139 if (ret == 0) {
2140 return -EEXIST;
2141 }
2142 if (ret < 0)
2143 goto out;
2144
2145 slot_orig = path->slots[0];
2146 leaf = path->nodes[0];
2147
2148 nritems = btrfs_header_nritems(leaf);
2149 data_end = leaf_data_end(root, leaf);
2150
2151 if (btrfs_leaf_free_space(root, leaf) <
2152 sizeof(struct btrfs_item) + data_size) {
2153 btrfs_print_leaf(root, leaf);
2154 printk("not enough freespace need %u have %d\n",
2155 data_size, btrfs_leaf_free_space(root, leaf));
2156 BUG();
2157 }
2158
2159 slot = path->slots[0];
2160 BUG_ON(slot < 0);
2161
2162 if (slot != nritems) {
2163 int i;
2164 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2165
2166 if (old_data < data_end) {
2167 btrfs_print_leaf(root, leaf);
2168 printk("slot %d old_data %d data_end %d\n",
2169 slot, old_data, data_end);
2170 BUG_ON(1);
2171 }
2172 /*
2173 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2174 */
2175 /* first correct the data pointers */
2176 WARN_ON(leaf->map_token);
2177 for (i = slot; i < nritems; i++) {
2178 u32 ioff;
2179
2180 item = btrfs_item_nr(leaf, i);
2181 if (!leaf->map_token) {
2182 map_extent_buffer(leaf, (unsigned long)item,
2183 sizeof(struct btrfs_item),
2184 &leaf->map_token, &leaf->kaddr,
2185 &leaf->map_start, &leaf->map_len,
2186 KM_USER1);
2187 }
2188
2189 ioff = btrfs_item_offset(leaf, item);
2190 btrfs_set_item_offset(leaf, item, ioff - data_size);
2191 }
2192 if (leaf->map_token) {
2193 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2194 leaf->map_token = NULL;
2195 }
2196
2197 /* shift the items */
2198 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1),
2199 btrfs_item_nr_offset(slot),
2200 (nritems - slot) * sizeof(struct btrfs_item));
2201
2202 /* shift the data */
2203 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2204 data_end - data_size, btrfs_leaf_data(leaf) +
2205 data_end, old_data - data_end);
2206 data_end = old_data;
2207 }
2208
2209 /* setup the item for the new data */
2210 btrfs_set_item_key(leaf, &disk_key, slot);
2211 item = btrfs_item_nr(leaf, slot);
2212 btrfs_set_item_offset(leaf, item, data_end - data_size);
2213 btrfs_set_item_size(leaf, item, data_size);
2214 btrfs_set_header_nritems(leaf, nritems + 1);
2215 btrfs_mark_buffer_dirty(leaf);
2216
2217 ret = 0;
2218 if (slot == 0)
2219 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2220
2221 if (btrfs_leaf_free_space(root, leaf) < 0) {
2222 btrfs_print_leaf(root, leaf);
2223 BUG();
2224 }
2225 out:
2226 return ret;
2227 }
2228
2229 /*
2230 * Given a key and some data, insert an item into the tree.
2231 * This does all the path init required, making room in the tree if needed.
2232 */
2233 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2234 *root, struct btrfs_key *cpu_key, void *data, u32
2235 data_size)
2236 {
2237 int ret = 0;
2238 struct btrfs_path *path;
2239 struct extent_buffer *leaf;
2240 unsigned long ptr;
2241
2242 path = btrfs_alloc_path();
2243 BUG_ON(!path);
2244 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2245 if (!ret) {
2246 leaf = path->nodes[0];
2247 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2248 write_extent_buffer(leaf, data, ptr, data_size);
2249 btrfs_mark_buffer_dirty(leaf);
2250 }
2251 btrfs_free_path(path);
2252 return ret;
2253 }
2254
2255 /*
2256 * delete the pointer from a given node.
2257 *
2258 * If the delete empties a node, the node is removed from the tree,
2259 * continuing all the way the root if required. The root is converted into
2260 * a leaf if all the nodes are emptied.
2261 */
2262 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2263 struct btrfs_path *path, int level, int slot)
2264 {
2265 struct extent_buffer *parent = path->nodes[level];
2266 u32 nritems;
2267 int ret = 0;
2268 int wret;
2269
2270 nritems = btrfs_header_nritems(parent);
2271 if (slot != nritems -1) {
2272 memmove_extent_buffer(parent,
2273 btrfs_node_key_ptr_offset(slot),
2274 btrfs_node_key_ptr_offset(slot + 1),
2275 sizeof(struct btrfs_key_ptr) *
2276 (nritems - slot - 1));
2277 }
2278 nritems--;
2279 btrfs_set_header_nritems(parent, nritems);
2280 if (nritems == 0 && parent == root->node) {
2281 BUG_ON(btrfs_header_level(root->node) != 1);
2282 /* just turn the root into a leaf and break */
2283 btrfs_set_header_level(root->node, 0);
2284 } else if (slot == 0) {
2285 struct btrfs_disk_key disk_key;
2286
2287 btrfs_node_key(parent, &disk_key, 0);
2288 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2289 if (wret)
2290 ret = wret;
2291 }
2292 btrfs_mark_buffer_dirty(parent);
2293 return ret;
2294 }
2295
2296 /*
2297 * delete the item at the leaf level in path. If that empties
2298 * the leaf, remove it from the tree
2299 */
2300 int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2301 struct btrfs_path *path)
2302 {
2303 int slot;
2304 struct extent_buffer *leaf;
2305 struct btrfs_item *item;
2306 int doff;
2307 int dsize;
2308 int ret = 0;
2309 int wret;
2310 u32 nritems;
2311
2312 leaf = path->nodes[0];
2313 slot = path->slots[0];
2314 doff = btrfs_item_offset_nr(leaf, slot);
2315 dsize = btrfs_item_size_nr(leaf, slot);
2316 nritems = btrfs_header_nritems(leaf);
2317
2318 if (slot != nritems - 1) {
2319 int i;
2320 int data_end = leaf_data_end(root, leaf);
2321
2322 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2323 data_end + dsize,
2324 btrfs_leaf_data(leaf) + data_end,
2325 doff - data_end);
2326
2327 for (i = slot + 1; i < nritems; i++) {
2328 u32 ioff;
2329
2330 item = btrfs_item_nr(leaf, i);
2331 if (!leaf->map_token) {
2332 map_extent_buffer(leaf, (unsigned long)item,
2333 sizeof(struct btrfs_item),
2334 &leaf->map_token, &leaf->kaddr,
2335 &leaf->map_start, &leaf->map_len,
2336 KM_USER1);
2337 }
2338 ioff = btrfs_item_offset(leaf, item);
2339 btrfs_set_item_offset(leaf, item, ioff + dsize);
2340 }
2341
2342 if (leaf->map_token) {
2343 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2344 leaf->map_token = NULL;
2345 }
2346
2347 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2348 btrfs_item_nr_offset(slot + 1),
2349 sizeof(struct btrfs_item) *
2350 (nritems - slot - 1));
2351 }
2352 btrfs_set_header_nritems(leaf, nritems - 1);
2353 nritems--;
2354
2355 /* delete the leaf if we've emptied it */
2356 if (nritems == 0) {
2357 if (leaf == root->node) {
2358 btrfs_set_header_level(leaf, 0);
2359 } else {
2360 clean_tree_block(trans, root, leaf);
2361 wait_on_tree_block_writeback(root, leaf);
2362 wret = del_ptr(trans, root, path, 1, path->slots[1]);
2363 if (wret)
2364 ret = wret;
2365 wret = btrfs_free_extent(trans, root,
2366 leaf->start, leaf->len, 1);
2367 if (wret)
2368 ret = wret;
2369 }
2370 } else {
2371 int used = leaf_space_used(leaf, 0, nritems);
2372 if (slot == 0) {
2373 struct btrfs_disk_key disk_key;
2374
2375 btrfs_item_key(leaf, &disk_key, 0);
2376 wret = fixup_low_keys(trans, root, path,
2377 &disk_key, 1);
2378 if (wret)
2379 ret = wret;
2380 }
2381
2382 /* delete the leaf if it is mostly empty */
2383 if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) {
2384 /* push_leaf_left fixes the path.
2385 * make sure the path still points to our leaf
2386 * for possible call to del_ptr below
2387 */
2388 slot = path->slots[1];
2389 extent_buffer_get(leaf);
2390
2391 wret = push_leaf_left(trans, root, path, 1);
2392 if (wret < 0 && wret != -ENOSPC)
2393 ret = wret;
2394
2395 if (path->nodes[0] == leaf &&
2396 btrfs_header_nritems(leaf)) {
2397 wret = push_leaf_right(trans, root, path, 1);
2398 if (wret < 0 && wret != -ENOSPC)
2399 ret = wret;
2400 }
2401
2402 if (btrfs_header_nritems(leaf) == 0) {
2403 u64 bytenr = leaf->start;
2404 u32 blocksize = leaf->len;
2405
2406 clean_tree_block(trans, root, leaf);
2407 wait_on_tree_block_writeback(root, leaf);
2408
2409 wret = del_ptr(trans, root, path, 1, slot);
2410 if (wret)
2411 ret = wret;
2412
2413 free_extent_buffer(leaf);
2414 wret = btrfs_free_extent(trans, root, bytenr,
2415 blocksize, 1);
2416 if (wret)
2417 ret = wret;
2418 } else {
2419 btrfs_mark_buffer_dirty(leaf);
2420 free_extent_buffer(leaf);
2421 }
2422 } else {
2423 btrfs_mark_buffer_dirty(leaf);
2424 }
2425 }
2426 return ret;
2427 }
2428
2429 /*
2430 * walk up the tree as far as required to find the next leaf.
2431 * returns 0 if it found something or 1 if there are no greater leaves.
2432 * returns < 0 on io errors.
2433 */
2434 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2435 {
2436 int slot;
2437 int level = 1;
2438 u64 bytenr;
2439 struct extent_buffer *c;
2440 struct extent_buffer *next = NULL;
2441
2442 while(level < BTRFS_MAX_LEVEL) {
2443 if (!path->nodes[level])
2444 return 1;
2445
2446 slot = path->slots[level] + 1;
2447 c = path->nodes[level];
2448 if (slot >= btrfs_header_nritems(c)) {
2449 level++;
2450 continue;
2451 }
2452
2453 bytenr = btrfs_node_blockptr(c, slot);
2454 if (next)
2455 free_extent_buffer(next);
2456
2457 if (path->reada)
2458 reada_for_search(root, path, level, slot);
2459
2460 next = read_tree_block(root, bytenr,
2461 btrfs_level_size(root, level -1));
2462 break;
2463 }
2464 path->slots[level] = slot;
2465 while(1) {
2466 level--;
2467 c = path->nodes[level];
2468 free_extent_buffer(c);
2469 path->nodes[level] = next;
2470 path->slots[level] = 0;
2471 if (!level)
2472 break;
2473 if (path->reada)
2474 reada_for_search(root, path, level, 0);
2475 next = read_tree_block(root, btrfs_node_blockptr(next, 0),
2476 btrfs_level_size(root, level - 1));
2477 }
2478 return 0;
2479 }
Linux kernel - Deliverables
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