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