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Btrfs: Change push_leaf_{leaf,right} to empty the src leave during item deletion
[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 /*
165 * compare two keys in a memcmp fashion
166 */
167 static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
168 {
169 struct btrfs_key k1;
170
171 btrfs_disk_key_to_cpu(&k1, disk);
172
173 if (k1.objectid > k2->objectid)
174 return 1;
175 if (k1.objectid < k2->objectid)
176 return -1;
177 if (k1.type > k2->type)
178 return 1;
179 if (k1.type < k2->type)
180 return -1;
181 if (k1.offset > k2->offset)
182 return 1;
183 if (k1.offset < k2->offset)
184 return -1;
185 return 0;
186 }
187
188
189 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
190 struct btrfs_root *root, struct extent_buffer *parent,
191 int start_slot, int cache_only, u64 *last_ret,
192 struct btrfs_key *progress)
193 {
194 struct extent_buffer *cur;
195 struct extent_buffer *tmp;
196 u64 blocknr;
197 u64 search_start = *last_ret;
198 u64 last_block = 0;
199 u64 other;
200 u32 parent_nritems;
201 int end_slot;
202 int i;
203 int err = 0;
204 int parent_level;
205 int uptodate;
206 u32 blocksize;
207 int progress_passed = 0;
208 struct btrfs_disk_key disk_key;
209
210 parent_level = btrfs_header_level(parent);
211 if (cache_only && parent_level != 1)
212 return 0;
213
214 if (trans->transaction != root->fs_info->running_transaction) {
215 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
216 root->fs_info->running_transaction->transid);
217 WARN_ON(1);
218 }
219 if (trans->transid != root->fs_info->generation) {
220 printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
221 root->fs_info->generation);
222 WARN_ON(1);
223 }
224
225 parent_nritems = btrfs_header_nritems(parent);
226 blocksize = btrfs_level_size(root, parent_level - 1);
227 end_slot = parent_nritems;
228
229 if (parent_nritems == 1)
230 return 0;
231
232 for (i = start_slot; i < end_slot; i++) {
233 int close = 1;
234
235 if (!parent->map_token) {
236 map_extent_buffer(parent,
237 btrfs_node_key_ptr_offset(i),
238 sizeof(struct btrfs_key_ptr),
239 &parent->map_token, &parent->kaddr,
240 &parent->map_start, &parent->map_len,
241 KM_USER1);
242 }
243 btrfs_node_key(parent, &disk_key, i);
244 if (!progress_passed && comp_keys(&disk_key, progress) < 0)
245 continue;
246
247 progress_passed = 1;
248 blocknr = btrfs_node_blockptr(parent, i);
249 if (last_block == 0)
250 last_block = blocknr;
251
252 if (i > 0) {
253 other = btrfs_node_blockptr(parent, i - 1);
254 close = close_blocks(blocknr, other, blocksize);
255 }
256 if (close && i < end_slot - 2) {
257 other = btrfs_node_blockptr(parent, i + 1);
258 close = close_blocks(blocknr, other, blocksize);
259 }
260 if (close) {
261 last_block = blocknr;
262 continue;
263 }
264 if (parent->map_token) {
265 unmap_extent_buffer(parent, parent->map_token,
266 KM_USER1);
267 parent->map_token = NULL;
268 }
269
270 cur = btrfs_find_tree_block(root, blocknr, blocksize);
271 if (cur)
272 uptodate = btrfs_buffer_uptodate(cur);
273 else
274 uptodate = 0;
275 if (!cur || !uptodate) {
276 if (cache_only) {
277 free_extent_buffer(cur);
278 continue;
279 }
280 if (!cur) {
281 cur = read_tree_block(root, blocknr,
282 blocksize);
283 } else if (!uptodate) {
284 btrfs_read_buffer(cur);
285 }
286 }
287 if (search_start == 0)
288 search_start = last_block;
289
290 err = __btrfs_cow_block(trans, root, cur, parent, i,
291 &tmp, search_start,
292 min(16 * blocksize,
293 (end_slot - i) * blocksize));
294 if (err) {
295 free_extent_buffer(cur);
296 break;
297 }
298 search_start = tmp->start;
299 last_block = tmp->start;
300 *last_ret = search_start;
301 if (parent_level == 1)
302 btrfs_clear_buffer_defrag(tmp);
303 free_extent_buffer(tmp);
304 }
305 if (parent->map_token) {
306 unmap_extent_buffer(parent, parent->map_token,
307 KM_USER1);
308 parent->map_token = NULL;
309 }
310 return err;
311 }
312
313 /*
314 * The leaf data grows from end-to-front in the node.
315 * this returns the address of the start of the last item,
316 * which is the stop of the leaf data stack
317 */
318 static inline unsigned int leaf_data_end(struct btrfs_root *root,
319 struct extent_buffer *leaf)
320 {
321 u32 nr = btrfs_header_nritems(leaf);
322 if (nr == 0)
323 return BTRFS_LEAF_DATA_SIZE(root);
324 return btrfs_item_offset_nr(leaf, nr - 1);
325 }
326
327 static int check_node(struct btrfs_root *root, struct btrfs_path *path,
328 int level)
329 {
330 struct extent_buffer *parent = NULL;
331 struct extent_buffer *node = path->nodes[level];
332 struct btrfs_disk_key parent_key;
333 struct btrfs_disk_key node_key;
334 int parent_slot;
335 int slot;
336 struct btrfs_key cpukey;
337 u32 nritems = btrfs_header_nritems(node);
338
339 if (path->nodes[level + 1])
340 parent = path->nodes[level + 1];
341
342 slot = path->slots[level];
343 BUG_ON(nritems == 0);
344 if (parent) {
345 parent_slot = path->slots[level + 1];
346 btrfs_node_key(parent, &parent_key, parent_slot);
347 btrfs_node_key(node, &node_key, 0);
348 BUG_ON(memcmp(&parent_key, &node_key,
349 sizeof(struct btrfs_disk_key)));
350 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
351 btrfs_header_bytenr(node));
352 }
353 BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
354 if (slot != 0) {
355 btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
356 btrfs_node_key(node, &node_key, slot);
357 BUG_ON(comp_keys(&node_key, &cpukey) <= 0);
358 }
359 if (slot < nritems - 1) {
360 btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
361 btrfs_node_key(node, &node_key, slot);
362 BUG_ON(comp_keys(&node_key, &cpukey) >= 0);
363 }
364 return 0;
365 }
366
367 static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
368 int level)
369 {
370 struct extent_buffer *leaf = path->nodes[level];
371 struct extent_buffer *parent = NULL;
372 int parent_slot;
373 struct btrfs_key cpukey;
374 struct btrfs_disk_key parent_key;
375 struct btrfs_disk_key leaf_key;
376 int slot = path->slots[0];
377
378 u32 nritems = btrfs_header_nritems(leaf);
379
380 if (path->nodes[level + 1])
381 parent = path->nodes[level + 1];
382
383 if (nritems == 0)
384 return 0;
385
386 if (parent) {
387 parent_slot = path->slots[level + 1];
388 btrfs_node_key(parent, &parent_key, parent_slot);
389 btrfs_item_key(leaf, &leaf_key, 0);
390
391 BUG_ON(memcmp(&parent_key, &leaf_key,
392 sizeof(struct btrfs_disk_key)));
393 BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
394 btrfs_header_bytenr(leaf));
395 }
396 #if 0
397 for (i = 0; nritems > 1 && i < nritems - 2; i++) {
398 btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
399 btrfs_item_key(leaf, &leaf_key, i);
400 if (comp_keys(&leaf_key, &cpukey) >= 0) {
401 btrfs_print_leaf(root, leaf);
402 printk("slot %d offset bad key\n", i);
403 BUG_ON(1);
404 }
405 if (btrfs_item_offset_nr(leaf, i) !=
406 btrfs_item_end_nr(leaf, i + 1)) {
407 btrfs_print_leaf(root, leaf);
408 printk("slot %d offset bad\n", i);
409 BUG_ON(1);
410 }
411 if (i == 0) {
412 if (btrfs_item_offset_nr(leaf, i) +
413 btrfs_item_size_nr(leaf, i) !=
414 BTRFS_LEAF_DATA_SIZE(root)) {
415 btrfs_print_leaf(root, leaf);
416 printk("slot %d first offset bad\n", i);
417 BUG_ON(1);
418 }
419 }
420 }
421 if (nritems > 0) {
422 if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
423 btrfs_print_leaf(root, leaf);
424 printk("slot %d bad size \n", nritems - 1);
425 BUG_ON(1);
426 }
427 }
428 #endif
429 if (slot != 0 && slot < nritems - 1) {
430 btrfs_item_key(leaf, &leaf_key, slot);
431 btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
432 if (comp_keys(&leaf_key, &cpukey) <= 0) {
433 btrfs_print_leaf(root, leaf);
434 printk("slot %d offset bad key\n", slot);
435 BUG_ON(1);
436 }
437 if (btrfs_item_offset_nr(leaf, slot - 1) !=
438 btrfs_item_end_nr(leaf, slot)) {
439 btrfs_print_leaf(root, leaf);
440 printk("slot %d offset bad\n", slot);
441 BUG_ON(1);
442 }
443 }
444 if (slot < nritems - 1) {
445 btrfs_item_key(leaf, &leaf_key, slot);
446 btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
447 BUG_ON(comp_keys(&leaf_key, &cpukey) >= 0);
448 if (btrfs_item_offset_nr(leaf, slot) !=
449 btrfs_item_end_nr(leaf, slot + 1)) {
450 btrfs_print_leaf(root, leaf);
451 printk("slot %d offset bad\n", slot);
452 BUG_ON(1);
453 }
454 }
455 BUG_ON(btrfs_item_offset_nr(leaf, 0) +
456 btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
457 return 0;
458 }
459
460 static int check_block(struct btrfs_root *root, struct btrfs_path *path,
461 int level)
462 {
463 return 0;
464 #if 0
465 struct extent_buffer *buf = path->nodes[level];
466
467 if (memcmp_extent_buffer(buf, root->fs_info->fsid,
468 (unsigned long)btrfs_header_fsid(buf),
469 BTRFS_FSID_SIZE)) {
470 printk("warning bad block %Lu\n", buf->start);
471 return 1;
472 }
473 #endif
474 if (level == 0)
475 return check_leaf(root, path, level);
476 return check_node(root, path, level);
477 }
478
479 /*
480 * search for key in the extent_buffer. The items start at offset p,
481 * and they are item_size apart. There are 'max' items in p.
482 *
483 * the slot in the array is returned via slot, and it points to
484 * the place where you would insert key if it is not found in
485 * the array.
486 *
487 * slot may point to max if the key is bigger than all of the keys
488 */
489 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
490 int item_size, struct btrfs_key *key,
491 int max, int *slot)
492 {
493 int low = 0;
494 int high = max;
495 int mid;
496 int ret;
497 struct btrfs_disk_key *tmp = NULL;
498 struct btrfs_disk_key unaligned;
499 unsigned long offset;
500 char *map_token = NULL;
501 char *kaddr = NULL;
502 unsigned long map_start = 0;
503 unsigned long map_len = 0;
504 int err;
505
506 while(low < high) {
507 mid = (low + high) / 2;
508 offset = p + mid * item_size;
509
510 if (!map_token || offset < map_start ||
511 (offset + sizeof(struct btrfs_disk_key)) >
512 map_start + map_len) {
513 if (map_token) {
514 unmap_extent_buffer(eb, map_token, KM_USER0);
515 map_token = NULL;
516 }
517 err = map_extent_buffer(eb, offset,
518 sizeof(struct btrfs_disk_key),
519 &map_token, &kaddr,
520 &map_start, &map_len, KM_USER0);
521
522 if (!err) {
523 tmp = (struct btrfs_disk_key *)(kaddr + offset -
524 map_start);
525 } else {
526 read_extent_buffer(eb, &unaligned,
527 offset, sizeof(unaligned));
528 tmp = &unaligned;
529 }
530
531 } else {
532 tmp = (struct btrfs_disk_key *)(kaddr + offset -
533 map_start);
534 }
535 ret = comp_keys(tmp, key);
536
537 if (ret < 0)
538 low = mid + 1;
539 else if (ret > 0)
540 high = mid;
541 else {
542 *slot = mid;
543 if (map_token)
544 unmap_extent_buffer(eb, map_token, KM_USER0);
545 return 0;
546 }
547 }
548 *slot = low;
549 if (map_token)
550 unmap_extent_buffer(eb, map_token, KM_USER0);
551 return 1;
552 }
553
554 /*
555 * simple bin_search frontend that does the right thing for
556 * leaves vs nodes
557 */
558 static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
559 int level, int *slot)
560 {
561 if (level == 0) {
562 return generic_bin_search(eb,
563 offsetof(struct btrfs_leaf, items),
564 sizeof(struct btrfs_item),
565 key, btrfs_header_nritems(eb),
566 slot);
567 } else {
568 return generic_bin_search(eb,
569 offsetof(struct btrfs_node, ptrs),
570 sizeof(struct btrfs_key_ptr),
571 key, btrfs_header_nritems(eb),
572 slot);
573 }
574 return -1;
575 }
576
577 static struct extent_buffer *read_node_slot(struct btrfs_root *root,
578 struct extent_buffer *parent, int slot)
579 {
580 if (slot < 0)
581 return NULL;
582 if (slot >= btrfs_header_nritems(parent))
583 return NULL;
584 return read_tree_block(root, btrfs_node_blockptr(parent, slot),
585 btrfs_level_size(root, btrfs_header_level(parent) - 1));
586 }
587
588 static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
589 *root, struct btrfs_path *path, int level)
590 {
591 struct extent_buffer *right = NULL;
592 struct extent_buffer *mid;
593 struct extent_buffer *left = NULL;
594 struct extent_buffer *parent = NULL;
595 int ret = 0;
596 int wret;
597 int pslot;
598 int orig_slot = path->slots[level];
599 int err_on_enospc = 0;
600 u64 orig_ptr;
601
602 if (level == 0)
603 return 0;
604
605 mid = path->nodes[level];
606 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
607
608 if (level < BTRFS_MAX_LEVEL - 1)
609 parent = path->nodes[level + 1];
610 pslot = path->slots[level + 1];
611
612 /*
613 * deal with the case where there is only one pointer in the root
614 * by promoting the node below to a root
615 */
616 if (!parent) {
617 struct extent_buffer *child;
618
619 if (btrfs_header_nritems(mid) != 1)
620 return 0;
621
622 /* promote the child to a root */
623 child = read_node_slot(root, mid, 0);
624 BUG_ON(!child);
625 root->node = child;
626 path->nodes[level] = NULL;
627 clean_tree_block(trans, root, mid);
628 wait_on_tree_block_writeback(root, mid);
629 /* once for the path */
630 free_extent_buffer(mid);
631 ret = btrfs_free_extent(trans, root, mid->start, mid->len, 1);
632 /* once for the root ptr */
633 free_extent_buffer(mid);
634 return ret;
635 }
636 if (btrfs_header_nritems(mid) >
637 BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
638 return 0;
639
640 if (btrfs_header_nritems(mid) < 2)
641 err_on_enospc = 1;
642
643 left = read_node_slot(root, parent, pslot - 1);
644 if (left) {
645 wret = btrfs_cow_block(trans, root, left,
646 parent, pslot - 1, &left);
647 if (wret) {
648 ret = wret;
649 goto enospc;
650 }
651 }
652 right = read_node_slot(root, parent, pslot + 1);
653 if (right) {
654 wret = btrfs_cow_block(trans, root, right,
655 parent, pslot + 1, &right);
656 if (wret) {
657 ret = wret;
658 goto enospc;
659 }
660 }
661
662 /* first, try to make some room in the middle buffer */
663 if (left) {
664 orig_slot += btrfs_header_nritems(left);
665 wret = push_node_left(trans, root, left, mid);
666 if (wret < 0)
667 ret = wret;
668 if (btrfs_header_nritems(mid) < 2)
669 err_on_enospc = 1;
670 }
671
672 /*
673 * then try to empty the right most buffer into the middle
674 */
675 if (right) {
676 wret = push_node_left(trans, root, mid, right);
677 if (wret < 0 && wret != -ENOSPC)
678 ret = wret;
679 if (btrfs_header_nritems(right) == 0) {
680 u64 bytenr = right->start;
681 u32 blocksize = right->len;
682
683 clean_tree_block(trans, root, right);
684 wait_on_tree_block_writeback(root, right);
685 free_extent_buffer(right);
686 right = NULL;
687 wret = del_ptr(trans, root, path, level + 1, pslot +
688 1);
689 if (wret)
690 ret = wret;
691 wret = btrfs_free_extent(trans, root, bytenr,
692 blocksize, 1);
693 if (wret)
694 ret = wret;
695 } else {
696 struct btrfs_disk_key right_key;
697 btrfs_node_key(right, &right_key, 0);
698 btrfs_set_node_key(parent, &right_key, pslot + 1);
699 btrfs_mark_buffer_dirty(parent);
700 }
701 }
702 if (btrfs_header_nritems(mid) == 1) {
703 /*
704 * we're not allowed to leave a node with one item in the
705 * tree during a delete. A deletion from lower in the tree
706 * could try to delete the only pointer in this node.
707 * So, pull some keys from the left.
708 * There has to be a left pointer at this point because
709 * otherwise we would have pulled some pointers from the
710 * right
711 */
712 BUG_ON(!left);
713 wret = balance_node_right(trans, root, mid, left);
714 if (wret < 0) {
715 ret = wret;
716 goto enospc;
717 }
718 BUG_ON(wret == 1);
719 }
720 if (btrfs_header_nritems(mid) == 0) {
721 /* we've managed to empty the middle node, drop it */
722 u64 bytenr = mid->start;
723 u32 blocksize = mid->len;
724 clean_tree_block(trans, root, mid);
725 wait_on_tree_block_writeback(root, mid);
726 free_extent_buffer(mid);
727 mid = NULL;
728 wret = del_ptr(trans, root, path, level + 1, pslot);
729 if (wret)
730 ret = wret;
731 wret = btrfs_free_extent(trans, root, bytenr, blocksize, 1);
732 if (wret)
733 ret = wret;
734 } else {
735 /* update the parent key to reflect our changes */
736 struct btrfs_disk_key mid_key;
737 btrfs_node_key(mid, &mid_key, 0);
738 btrfs_set_node_key(parent, &mid_key, pslot);
739 btrfs_mark_buffer_dirty(parent);
740 }
741
742 /* update the path */
743 if (left) {
744 if (btrfs_header_nritems(left) > orig_slot) {
745 extent_buffer_get(left);
746 path->nodes[level] = left;
747 path->slots[level + 1] -= 1;
748 path->slots[level] = orig_slot;
749 if (mid)
750 free_extent_buffer(mid);
751 } else {
752 orig_slot -= btrfs_header_nritems(left);
753 path->slots[level] = orig_slot;
754 }
755 }
756 /* double check we haven't messed things up */
757 check_block(root, path, level);
758 if (orig_ptr !=
759 btrfs_node_blockptr(path->nodes[level], path->slots[level]))
760 BUG();
761 enospc:
762 if (right)
763 free_extent_buffer(right);
764 if (left)
765 free_extent_buffer(left);
766 return ret;
767 }
768
769 /* returns zero if the push worked, non-zero otherwise */
770 static int push_nodes_for_insert(struct btrfs_trans_handle *trans,
771 struct btrfs_root *root,
772 struct btrfs_path *path, int level)
773 {
774 struct extent_buffer *right = NULL;
775 struct extent_buffer *mid;
776 struct extent_buffer *left = NULL;
777 struct extent_buffer *parent = NULL;
778 int ret = 0;
779 int wret;
780 int pslot;
781 int orig_slot = path->slots[level];
782 u64 orig_ptr;
783
784 if (level == 0)
785 return 1;
786
787 mid = path->nodes[level];
788 orig_ptr = btrfs_node_blockptr(mid, orig_slot);
789
790 if (level < BTRFS_MAX_LEVEL - 1)
791 parent = path->nodes[level + 1];
792 pslot = path->slots[level + 1];
793
794 if (!parent)
795 return 1;
796
797 left = read_node_slot(root, parent, pslot - 1);
798
799 /* first, try to make some room in the middle buffer */
800 if (left) {
801 u32 left_nr;
802 left_nr = btrfs_header_nritems(left);
803 if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
804 wret = 1;
805 } else {
806 ret = btrfs_cow_block(trans, root, left, parent,
807 pslot - 1, &left);
808 if (ret)
809 wret = 1;
810 else {
811 wret = push_node_left(trans, root,
812 left, mid);
813 }
814 }
815 if (wret < 0)
816 ret = wret;
817 if (wret == 0) {
818 struct btrfs_disk_key disk_key;
819 orig_slot += left_nr;
820 btrfs_node_key(mid, &disk_key, 0);
821 btrfs_set_node_key(parent, &disk_key, pslot);
822 btrfs_mark_buffer_dirty(parent);
823 if (btrfs_header_nritems(left) > orig_slot) {
824 path->nodes[level] = left;
825 path->slots[level + 1] -= 1;
826 path->slots[level] = orig_slot;
827 free_extent_buffer(mid);
828 } else {
829 orig_slot -=
830 btrfs_header_nritems(left);
831 path->slots[level] = orig_slot;
832 free_extent_buffer(left);
833 }
834 return 0;
835 }
836 free_extent_buffer(left);
837 }
838 right= read_node_slot(root, parent, pslot + 1);
839
840 /*
841 * then try to empty the right most buffer into the middle
842 */
843 if (right) {
844 u32 right_nr;
845 right_nr = btrfs_header_nritems(right);
846 if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
847 wret = 1;
848 } else {
849 ret = btrfs_cow_block(trans, root, right,
850 parent, pslot + 1,
851 &right);
852 if (ret)
853 wret = 1;
854 else {
855 wret = balance_node_right(trans, root,
856 right, mid);
857 }
858 }
859 if (wret < 0)
860 ret = wret;
861 if (wret == 0) {
862 struct btrfs_disk_key disk_key;
863
864 btrfs_node_key(right, &disk_key, 0);
865 btrfs_set_node_key(parent, &disk_key, pslot + 1);
866 btrfs_mark_buffer_dirty(parent);
867
868 if (btrfs_header_nritems(mid) <= orig_slot) {
869 path->nodes[level] = right;
870 path->slots[level + 1] += 1;
871 path->slots[level] = orig_slot -
872 btrfs_header_nritems(mid);
873 free_extent_buffer(mid);
874 } else {
875 free_extent_buffer(right);
876 }
877 return 0;
878 }
879 free_extent_buffer(right);
880 }
881 return 1;
882 }
883
884 /*
885 * readahead one full node of leaves
886 */
887 static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
888 int level, int slot)
889 {
890 struct extent_buffer *node;
891 u32 nritems;
892 u64 search;
893 u64 lowest_read;
894 u64 highest_read;
895 u64 nread = 0;
896 int direction = path->reada;
897 struct extent_buffer *eb;
898 u32 nr;
899 u32 blocksize;
900 u32 nscan = 0;
901
902 if (level != 1)
903 return;
904
905 if (!path->nodes[level])
906 return;
907
908 node = path->nodes[level];
909 search = btrfs_node_blockptr(node, slot);
910 blocksize = btrfs_level_size(root, level - 1);
911 eb = btrfs_find_tree_block(root, search, blocksize);
912 if (eb) {
913 free_extent_buffer(eb);
914 return;
915 }
916
917 highest_read = search;
918 lowest_read = search;
919
920 nritems = btrfs_header_nritems(node);
921 nr = slot;
922 while(1) {
923 if (direction < 0) {
924 if (nr == 0)
925 break;
926 nr--;
927 } else if (direction > 0) {
928 nr++;
929 if (nr >= nritems)
930 break;
931 }
932 search = btrfs_node_blockptr(node, nr);
933 if ((search >= lowest_read && search <= highest_read) ||
934 (search < lowest_read && lowest_read - search <= 32768) ||
935 (search > highest_read && search - highest_read <= 32768)) {
936 readahead_tree_block(root, search, blocksize);
937 nread += blocksize;
938 }
939 nscan++;
940 if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
941 break;
942 if(nread > (1024 * 1024) || nscan > 128)
943 break;
944
945 if (search < lowest_read)
946 lowest_read = search;
947 if (search > highest_read)
948 highest_read = search;
949 }
950 }
951 /*
952 * look for key in the tree. path is filled in with nodes along the way
953 * if key is found, we return zero and you can find the item in the leaf
954 * level of the path (level 0)
955 *
956 * If the key isn't found, the path points to the slot where it should
957 * be inserted, and 1 is returned. If there are other errors during the
958 * search a negative error number is returned.
959 *
960 * if ins_len > 0, nodes and leaves will be split as we walk down the
961 * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
962 * possible)
963 */
964 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
965 *root, struct btrfs_key *key, struct btrfs_path *p, int
966 ins_len, int cow)
967 {
968 struct extent_buffer *b;
969 u64 bytenr;
970 int slot;
971 int ret;
972 int level;
973 int should_reada = p->reada;
974 u8 lowest_level = 0;
975
976 lowest_level = p->lowest_level;
977 WARN_ON(lowest_level && ins_len);
978 WARN_ON(p->nodes[0] != NULL);
979 WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
980 again:
981 b = root->node;
982 extent_buffer_get(b);
983 while (b) {
984 level = btrfs_header_level(b);
985 if (cow) {
986 int wret;
987 wret = btrfs_cow_block(trans, root, b,
988 p->nodes[level + 1],
989 p->slots[level + 1],
990 &b);
991 if (wret) {
992 free_extent_buffer(b);
993 return wret;
994 }
995 }
996 BUG_ON(!cow && ins_len);
997 if (level != btrfs_header_level(b))
998 WARN_ON(1);
999 level = btrfs_header_level(b);
1000 p->nodes[level] = b;
1001 ret = check_block(root, p, level);
1002 if (ret)
1003 return -1;
1004 ret = bin_search(b, key, level, &slot);
1005 if (level != 0) {
1006 if (ret && slot > 0)
1007 slot -= 1;
1008 p->slots[level] = slot;
1009 if (ins_len > 0 && btrfs_header_nritems(b) >=
1010 BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1011 int sret = split_node(trans, root, p, level);
1012 BUG_ON(sret > 0);
1013 if (sret)
1014 return sret;
1015 b = p->nodes[level];
1016 slot = p->slots[level];
1017 } else if (ins_len < 0) {
1018 int sret = balance_level(trans, root, p,
1019 level);
1020 if (sret)
1021 return sret;
1022 b = p->nodes[level];
1023 if (!b) {
1024 btrfs_release_path(NULL, p);
1025 goto again;
1026 }
1027 slot = p->slots[level];
1028 BUG_ON(btrfs_header_nritems(b) == 1);
1029 }
1030 /* this is only true while dropping a snapshot */
1031 if (level == lowest_level)
1032 break;
1033 bytenr = btrfs_node_blockptr(b, slot);
1034 if (should_reada)
1035 reada_for_search(root, p, level, slot);
1036 b = read_tree_block(root, bytenr,
1037 btrfs_level_size(root, level - 1));
1038 } else {
1039 p->slots[level] = slot;
1040 if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
1041 sizeof(struct btrfs_item) + ins_len) {
1042 int sret = split_leaf(trans, root, key,
1043 p, ins_len, ret == 0);
1044 BUG_ON(sret > 0);
1045 if (sret)
1046 return sret;
1047 }
1048 return ret;
1049 }
1050 }
1051 return 1;
1052 }
1053
1054 /*
1055 * adjust the pointers going up the tree, starting at level
1056 * making sure the right key of each node is points to 'key'.
1057 * This is used after shifting pointers to the left, so it stops
1058 * fixing up pointers when a given leaf/node is not in slot 0 of the
1059 * higher levels
1060 *
1061 * If this fails to write a tree block, it returns -1, but continues
1062 * fixing up the blocks in ram so the tree is consistent.
1063 */
1064 static int fixup_low_keys(struct btrfs_trans_handle *trans,
1065 struct btrfs_root *root, struct btrfs_path *path,
1066 struct btrfs_disk_key *key, int level)
1067 {
1068 int i;
1069 int ret = 0;
1070 struct extent_buffer *t;
1071
1072 for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1073 int tslot = path->slots[i];
1074 if (!path->nodes[i])
1075 break;
1076 t = path->nodes[i];
1077 btrfs_set_node_key(t, key, tslot);
1078 btrfs_mark_buffer_dirty(path->nodes[i]);
1079 if (tslot != 0)
1080 break;
1081 }
1082 return ret;
1083 }
1084
1085 /*
1086 * try to push data from one node into the next node left in the
1087 * tree.
1088 *
1089 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
1090 * error, and > 0 if there was no room in the left hand block.
1091 */
1092 static int push_node_left(struct btrfs_trans_handle *trans, struct btrfs_root
1093 *root, struct extent_buffer *dst,
1094 struct extent_buffer *src)
1095 {
1096 int push_items = 0;
1097 int src_nritems;
1098 int dst_nritems;
1099 int ret = 0;
1100
1101 src_nritems = btrfs_header_nritems(src);
1102 dst_nritems = btrfs_header_nritems(dst);
1103 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1104
1105 if (push_items <= 0) {
1106 return 1;
1107 }
1108
1109 if (src_nritems < push_items)
1110 push_items = src_nritems;
1111
1112 copy_extent_buffer(dst, src,
1113 btrfs_node_key_ptr_offset(dst_nritems),
1114 btrfs_node_key_ptr_offset(0),
1115 push_items * sizeof(struct btrfs_key_ptr));
1116
1117 if (push_items < src_nritems) {
1118 memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
1119 btrfs_node_key_ptr_offset(push_items),
1120 (src_nritems - push_items) *
1121 sizeof(struct btrfs_key_ptr));
1122 }
1123 btrfs_set_header_nritems(src, src_nritems - push_items);
1124 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1125 btrfs_mark_buffer_dirty(src);
1126 btrfs_mark_buffer_dirty(dst);
1127 return ret;
1128 }
1129
1130 /*
1131 * try to push data from one node into the next node right in the
1132 * tree.
1133 *
1134 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
1135 * error, and > 0 if there was no room in the right hand block.
1136 *
1137 * this will only push up to 1/2 the contents of the left node over
1138 */
1139 static int balance_node_right(struct btrfs_trans_handle *trans,
1140 struct btrfs_root *root,
1141 struct extent_buffer *dst,
1142 struct extent_buffer *src)
1143 {
1144 int push_items = 0;
1145 int max_push;
1146 int src_nritems;
1147 int dst_nritems;
1148 int ret = 0;
1149
1150 src_nritems = btrfs_header_nritems(src);
1151 dst_nritems = btrfs_header_nritems(dst);
1152 push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1153 if (push_items <= 0)
1154 return 1;
1155
1156 max_push = src_nritems / 2 + 1;
1157 /* don't try to empty the node */
1158 if (max_push >= src_nritems)
1159 return 1;
1160
1161 if (max_push < push_items)
1162 push_items = max_push;
1163
1164 memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
1165 btrfs_node_key_ptr_offset(0),
1166 (dst_nritems) *
1167 sizeof(struct btrfs_key_ptr));
1168
1169 copy_extent_buffer(dst, src,
1170 btrfs_node_key_ptr_offset(0),
1171 btrfs_node_key_ptr_offset(src_nritems - push_items),
1172 push_items * sizeof(struct btrfs_key_ptr));
1173
1174 btrfs_set_header_nritems(src, src_nritems - push_items);
1175 btrfs_set_header_nritems(dst, dst_nritems + push_items);
1176
1177 btrfs_mark_buffer_dirty(src);
1178 btrfs_mark_buffer_dirty(dst);
1179 return ret;
1180 }
1181
1182 /*
1183 * helper function to insert a new root level in the tree.
1184 * A new node is allocated, and a single item is inserted to
1185 * point to the existing root
1186 *
1187 * returns zero on success or < 0 on failure.
1188 */
1189 static int insert_new_root(struct btrfs_trans_handle *trans,
1190 struct btrfs_root *root,
1191 struct btrfs_path *path, int level)
1192 {
1193 struct extent_buffer *lower;
1194 struct extent_buffer *c;
1195 struct btrfs_disk_key lower_key;
1196
1197 BUG_ON(path->nodes[level]);
1198 BUG_ON(path->nodes[level-1] != root->node);
1199
1200 c = btrfs_alloc_free_block(trans, root, root->nodesize,
1201 root->node->start, 0);
1202 if (IS_ERR(c))
1203 return PTR_ERR(c);
1204 memset_extent_buffer(c, 0, 0, root->nodesize);
1205 btrfs_set_header_nritems(c, 1);
1206 btrfs_set_header_level(c, level);
1207 btrfs_set_header_bytenr(c, c->start);
1208 btrfs_set_header_generation(c, trans->transid);
1209 btrfs_set_header_owner(c, root->root_key.objectid);
1210 lower = path->nodes[level-1];
1211
1212 write_extent_buffer(c, root->fs_info->fsid,
1213 (unsigned long)btrfs_header_fsid(c),
1214 BTRFS_FSID_SIZE);
1215 if (level == 1)
1216 btrfs_item_key(lower, &lower_key, 0);
1217 else
1218 btrfs_node_key(lower, &lower_key, 0);
1219 btrfs_set_node_key(c, &lower_key, 0);
1220 btrfs_set_node_blockptr(c, 0, lower->start);
1221
1222 btrfs_mark_buffer_dirty(c);
1223
1224 /* the super has an extra ref to root->node */
1225 free_extent_buffer(root->node);
1226 root->node = c;
1227 extent_buffer_get(c);
1228 path->nodes[level] = c;
1229 path->slots[level] = 0;
1230 return 0;
1231 }
1232
1233 /*
1234 * worker function to insert a single pointer in a node.
1235 * the node should have enough room for the pointer already
1236 *
1237 * slot and level indicate where you want the key to go, and
1238 * blocknr is the block the key points to.
1239 *
1240 * returns zero on success and < 0 on any error
1241 */
1242 static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
1243 *root, struct btrfs_path *path, struct btrfs_disk_key
1244 *key, u64 bytenr, int slot, int level)
1245 {
1246 struct extent_buffer *lower;
1247 int nritems;
1248
1249 BUG_ON(!path->nodes[level]);
1250 lower = path->nodes[level];
1251 nritems = btrfs_header_nritems(lower);
1252 if (slot > nritems)
1253 BUG();
1254 if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
1255 BUG();
1256 if (slot != nritems) {
1257 memmove_extent_buffer(lower,
1258 btrfs_node_key_ptr_offset(slot + 1),
1259 btrfs_node_key_ptr_offset(slot),
1260 (nritems - slot) * sizeof(struct btrfs_key_ptr));
1261 }
1262 btrfs_set_node_key(lower, key, slot);
1263 btrfs_set_node_blockptr(lower, slot, bytenr);
1264 btrfs_set_header_nritems(lower, nritems + 1);
1265 btrfs_mark_buffer_dirty(lower);
1266 return 0;
1267 }
1268
1269 /*
1270 * split the node at the specified level in path in two.
1271 * The path is corrected to point to the appropriate node after the split
1272 *
1273 * Before splitting this tries to make some room in the node by pushing
1274 * left and right, if either one works, it returns right away.
1275 *
1276 * returns 0 on success and < 0 on failure
1277 */
1278 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
1279 *root, struct btrfs_path *path, int level)
1280 {
1281 struct extent_buffer *c;
1282 struct extent_buffer *split;
1283 struct btrfs_disk_key disk_key;
1284 int mid;
1285 int ret;
1286 int wret;
1287 u32 c_nritems;
1288
1289 c = path->nodes[level];
1290 if (c == root->node) {
1291 /* trying to split the root, lets make a new one */
1292 ret = insert_new_root(trans, root, path, level + 1);
1293 if (ret)
1294 return ret;
1295 } else {
1296 ret = push_nodes_for_insert(trans, root, path, level);
1297 c = path->nodes[level];
1298 if (!ret && btrfs_header_nritems(c) <
1299 BTRFS_NODEPTRS_PER_BLOCK(root) - 1)
1300 return 0;
1301 if (ret < 0)
1302 return ret;
1303 }
1304
1305 c_nritems = btrfs_header_nritems(c);
1306 split = btrfs_alloc_free_block(trans, root, root->nodesize,
1307 c->start, 0);
1308 if (IS_ERR(split))
1309 return PTR_ERR(split);
1310
1311 btrfs_set_header_flags(split, btrfs_header_flags(c));
1312 btrfs_set_header_level(split, btrfs_header_level(c));
1313 btrfs_set_header_bytenr(split, split->start);
1314 btrfs_set_header_generation(split, trans->transid);
1315 btrfs_set_header_owner(split, root->root_key.objectid);
1316 write_extent_buffer(split, root->fs_info->fsid,
1317 (unsigned long)btrfs_header_fsid(split),
1318 BTRFS_FSID_SIZE);
1319
1320 mid = (c_nritems + 1) / 2;
1321
1322 copy_extent_buffer(split, c,
1323 btrfs_node_key_ptr_offset(0),
1324 btrfs_node_key_ptr_offset(mid),
1325 (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
1326 btrfs_set_header_nritems(split, c_nritems - mid);
1327 btrfs_set_header_nritems(c, mid);
1328 ret = 0;
1329
1330 btrfs_mark_buffer_dirty(c);
1331 btrfs_mark_buffer_dirty(split);
1332
1333 btrfs_node_key(split, &disk_key, 0);
1334 wret = insert_ptr(trans, root, path, &disk_key, split->start,
1335 path->slots[level + 1] + 1,
1336 level + 1);
1337 if (wret)
1338 ret = wret;
1339
1340 if (path->slots[level] >= mid) {
1341 path->slots[level] -= mid;
1342 free_extent_buffer(c);
1343 path->nodes[level] = split;
1344 path->slots[level + 1] += 1;
1345 } else {
1346 free_extent_buffer(split);
1347 }
1348 return ret;
1349 }
1350
1351 /*
1352 * how many bytes are required to store the items in a leaf. start
1353 * and nr indicate which items in the leaf to check. This totals up the
1354 * space used both by the item structs and the item data
1355 */
1356 static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1357 {
1358 int data_len;
1359 int nritems = btrfs_header_nritems(l);
1360 int end = min(nritems, start + nr) - 1;
1361
1362 if (!nr)
1363 return 0;
1364 data_len = btrfs_item_end_nr(l, start);
1365 data_len = data_len - btrfs_item_offset_nr(l, end);
1366 data_len += sizeof(struct btrfs_item) * nr;
1367 WARN_ON(data_len < 0);
1368 return data_len;
1369 }
1370
1371 /*
1372 * The space between the end of the leaf items and
1373 * the start of the leaf data. IOW, how much room
1374 * the leaf has left for both items and data
1375 */
1376 int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1377 {
1378 int nritems = btrfs_header_nritems(leaf);
1379 int ret;
1380 ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
1381 if (ret < 0) {
1382 printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
1383 ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
1384 leaf_space_used(leaf, 0, nritems), nritems);
1385 }
1386 return ret;
1387 }
1388
1389 /*
1390 * push some data in the path leaf to the right, trying to free up at
1391 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1392 *
1393 * returns 1 if the push failed because the other node didn't have enough
1394 * room, 0 if everything worked out and < 0 if there were major errors.
1395 */
1396 static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
1397 *root, struct btrfs_path *path, int data_size,
1398 int empty)
1399 {
1400 struct extent_buffer *left = path->nodes[0];
1401 struct extent_buffer *right;
1402 struct extent_buffer *upper;
1403 struct btrfs_disk_key disk_key;
1404 int slot;
1405 u32 i;
1406 int free_space;
1407 int push_space = 0;
1408 int push_items = 0;
1409 struct btrfs_item *item;
1410 u32 left_nritems;
1411 u32 nr;
1412 u32 right_nritems;
1413 u32 data_end;
1414 u32 this_item_size;
1415 int ret;
1416
1417 slot = path->slots[1];
1418 if (!path->nodes[1]) {
1419 return 1;
1420 }
1421 upper = path->nodes[1];
1422 if (slot >= btrfs_header_nritems(upper) - 1)
1423 return 1;
1424
1425 right = read_tree_block(root, btrfs_node_blockptr(upper, slot + 1),
1426 root->leafsize);
1427 free_space = btrfs_leaf_free_space(root, right);
1428 if (free_space < data_size + sizeof(struct btrfs_item)) {
1429 free_extent_buffer(right);
1430 return 1;
1431 }
1432
1433 /* cow and double check */
1434 ret = btrfs_cow_block(trans, root, right, upper,
1435 slot + 1, &right);
1436 if (ret) {
1437 free_extent_buffer(right);
1438 return 1;
1439 }
1440 free_space = btrfs_leaf_free_space(root, right);
1441 if (free_space < data_size + sizeof(struct btrfs_item)) {
1442 free_extent_buffer(right);
1443 return 1;
1444 }
1445
1446 left_nritems = btrfs_header_nritems(left);
1447 if (left_nritems == 0) {
1448 free_extent_buffer(right);
1449 return 1;
1450 }
1451
1452 if (empty)
1453 nr = 0;
1454 else
1455 nr = 1;
1456
1457 i = left_nritems - 1;
1458 while (i >= nr) {
1459 item = btrfs_item_nr(left, i);
1460
1461 if (path->slots[0] == i)
1462 push_space += data_size + sizeof(*item);
1463
1464 if (!left->map_token) {
1465 map_extent_buffer(left, (unsigned long)item,
1466 sizeof(struct btrfs_item),
1467 &left->map_token, &left->kaddr,
1468 &left->map_start, &left->map_len,
1469 KM_USER1);
1470 }
1471
1472 this_item_size = btrfs_item_size(left, item);
1473 if (this_item_size + sizeof(*item) + push_space > free_space)
1474 break;
1475 push_items++;
1476 push_space += this_item_size + sizeof(*item);
1477 if (i == 0)
1478 break;
1479 i--;
1480 }
1481 if (left->map_token) {
1482 unmap_extent_buffer(left, left->map_token, KM_USER1);
1483 left->map_token = NULL;
1484 }
1485
1486 if (push_items == 0) {
1487 free_extent_buffer(right);
1488 return 1;
1489 }
1490
1491 if (!empty && push_items == left_nritems)
1492 WARN_ON(1);
1493
1494 /* push left to right */
1495 right_nritems = btrfs_header_nritems(right);
1496
1497 push_space = btrfs_item_end_nr(left, left_nritems - push_items);
1498 push_space -= leaf_data_end(root, left);
1499
1500 /* make room in the right data area */
1501 data_end = leaf_data_end(root, right);
1502 memmove_extent_buffer(right,
1503 btrfs_leaf_data(right) + data_end - push_space,
1504 btrfs_leaf_data(right) + data_end,
1505 BTRFS_LEAF_DATA_SIZE(root) - data_end);
1506
1507 /* copy from the left data area */
1508 copy_extent_buffer(right, left, btrfs_leaf_data(right) +
1509 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1510 btrfs_leaf_data(left) + leaf_data_end(root, left),
1511 push_space);
1512
1513 memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
1514 btrfs_item_nr_offset(0),
1515 right_nritems * sizeof(struct btrfs_item));
1516
1517 /* copy the items from left to right */
1518 copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
1519 btrfs_item_nr_offset(left_nritems - push_items),
1520 push_items * sizeof(struct btrfs_item));
1521
1522 /* update the item pointers */
1523 right_nritems += push_items;
1524 btrfs_set_header_nritems(right, right_nritems);
1525 push_space = BTRFS_LEAF_DATA_SIZE(root);
1526 for (i = 0; i < right_nritems; i++) {
1527 item = btrfs_item_nr(right, i);
1528 if (!right->map_token) {
1529 map_extent_buffer(right, (unsigned long)item,
1530 sizeof(struct btrfs_item),
1531 &right->map_token, &right->kaddr,
1532 &right->map_start, &right->map_len,
1533 KM_USER1);
1534 }
1535 push_space -= btrfs_item_size(right, item);
1536 btrfs_set_item_offset(right, item, push_space);
1537 }
1538
1539 if (right->map_token) {
1540 unmap_extent_buffer(right, right->map_token, KM_USER1);
1541 right->map_token = NULL;
1542 }
1543 left_nritems -= push_items;
1544 btrfs_set_header_nritems(left, left_nritems);
1545
1546 if (left_nritems)
1547 btrfs_mark_buffer_dirty(left);
1548 btrfs_mark_buffer_dirty(right);
1549
1550 btrfs_item_key(right, &disk_key, 0);
1551 btrfs_set_node_key(upper, &disk_key, slot + 1);
1552 btrfs_mark_buffer_dirty(upper);
1553
1554 /* then fixup the leaf pointer in the path */
1555 if (path->slots[0] >= left_nritems) {
1556 path->slots[0] -= left_nritems;
1557 free_extent_buffer(path->nodes[0]);
1558 path->nodes[0] = right;
1559 path->slots[1] += 1;
1560 } else {
1561 free_extent_buffer(right);
1562 }
1563 return 0;
1564 }
1565 /*
1566 * push some data in the path leaf to the left, trying to free up at
1567 * least data_size bytes. returns zero if the push worked, nonzero otherwise
1568 */
1569 static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
1570 *root, struct btrfs_path *path, int data_size,
1571 int empty)
1572 {
1573 struct btrfs_disk_key disk_key;
1574 struct extent_buffer *right = path->nodes[0];
1575 struct extent_buffer *left;
1576 int slot;
1577 int i;
1578 int free_space;
1579 int push_space = 0;
1580 int push_items = 0;
1581 struct btrfs_item *item;
1582 u32 old_left_nritems;
1583 u32 right_nritems;
1584 u32 nr;
1585 int ret = 0;
1586 int wret;
1587 u32 this_item_size;
1588 u32 old_left_item_size;
1589
1590 slot = path->slots[1];
1591 if (slot == 0)
1592 return 1;
1593 if (!path->nodes[1])
1594 return 1;
1595
1596 right_nritems = btrfs_header_nritems(right);
1597 if (right_nritems == 0) {
1598 return 1;
1599 }
1600
1601 left = read_tree_block(root, btrfs_node_blockptr(path->nodes[1],
1602 slot - 1), root->leafsize);
1603 free_space = btrfs_leaf_free_space(root, left);
1604 if (free_space < data_size + sizeof(struct btrfs_item)) {
1605 free_extent_buffer(left);
1606 return 1;
1607 }
1608
1609 /* cow and double check */
1610 ret = btrfs_cow_block(trans, root, left,
1611 path->nodes[1], slot - 1, &left);
1612 if (ret) {
1613 /* we hit -ENOSPC, but it isn't fatal here */
1614 free_extent_buffer(left);
1615 return 1;
1616 }
1617
1618 free_space = btrfs_leaf_free_space(root, left);
1619 if (free_space < data_size + sizeof(struct btrfs_item)) {
1620 free_extent_buffer(left);
1621 return 1;
1622 }
1623
1624 if (empty)
1625 nr = right_nritems;
1626 else
1627 nr = right_nritems - 1;
1628
1629 for (i = 0; i < nr; i++) {
1630 item = btrfs_item_nr(right, i);
1631 if (!right->map_token) {
1632 map_extent_buffer(right, (unsigned long)item,
1633 sizeof(struct btrfs_item),
1634 &right->map_token, &right->kaddr,
1635 &right->map_start, &right->map_len,
1636 KM_USER1);
1637 }
1638
1639 if (path->slots[0] == i)
1640 push_space += data_size + sizeof(*item);
1641
1642 this_item_size = btrfs_item_size(right, item);
1643 if (this_item_size + sizeof(*item) + push_space > free_space)
1644 break;
1645
1646 push_items++;
1647 push_space += this_item_size + sizeof(*item);
1648 }
1649
1650 if (right->map_token) {
1651 unmap_extent_buffer(right, right->map_token, KM_USER1);
1652 right->map_token = NULL;
1653 }
1654
1655 if (push_items == 0) {
1656 free_extent_buffer(left);
1657 return 1;
1658 }
1659 if (!empty && push_items == btrfs_header_nritems(right))
1660 WARN_ON(1);
1661
1662 /* push data from right to left */
1663 copy_extent_buffer(left, right,
1664 btrfs_item_nr_offset(btrfs_header_nritems(left)),
1665 btrfs_item_nr_offset(0),
1666 push_items * sizeof(struct btrfs_item));
1667
1668 push_space = BTRFS_LEAF_DATA_SIZE(root) -
1669 btrfs_item_offset_nr(right, push_items -1);
1670
1671 copy_extent_buffer(left, right, btrfs_leaf_data(left) +
1672 leaf_data_end(root, left) - push_space,
1673 btrfs_leaf_data(right) +
1674 btrfs_item_offset_nr(right, push_items - 1),
1675 push_space);
1676 old_left_nritems = btrfs_header_nritems(left);
1677 BUG_ON(old_left_nritems < 0);
1678
1679 old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
1680 for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1681 u32 ioff;
1682
1683 item = btrfs_item_nr(left, i);
1684 if (!left->map_token) {
1685 map_extent_buffer(left, (unsigned long)item,
1686 sizeof(struct btrfs_item),
1687 &left->map_token, &left->kaddr,
1688 &left->map_start, &left->map_len,
1689 KM_USER1);
1690 }
1691
1692 ioff = btrfs_item_offset(left, item);
1693 btrfs_set_item_offset(left, item,
1694 ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
1695 }
1696 btrfs_set_header_nritems(left, old_left_nritems + push_items);
1697 if (left->map_token) {
1698 unmap_extent_buffer(left, left->map_token, KM_USER1);
1699 left->map_token = NULL;
1700 }
1701
1702 /* fixup right node */
1703 if (push_items > right_nritems) {
1704 printk("push items %d nr %u\n", push_items, right_nritems);
1705 WARN_ON(1);
1706 }
1707
1708 if (push_items < right_nritems) {
1709 push_space = btrfs_item_offset_nr(right, push_items - 1) -
1710 leaf_data_end(root, right);
1711 memmove_extent_buffer(right, btrfs_leaf_data(right) +
1712 BTRFS_LEAF_DATA_SIZE(root) - push_space,
1713 btrfs_leaf_data(right) +
1714 leaf_data_end(root, right), push_space);
1715
1716 memmove_extent_buffer(right, btrfs_item_nr_offset(0),
1717 btrfs_item_nr_offset(push_items),
1718 (btrfs_header_nritems(right) - push_items) *
1719 sizeof(struct btrfs_item));
1720
1721 }
1722 btrfs_set_header_nritems(right, right_nritems - push_items);
1723 push_space = BTRFS_LEAF_DATA_SIZE(root);
1724
1725 for (i = 0; i < right_nritems; i++) {
1726 item = btrfs_item_nr(right, i);
1727
1728 if (!right->map_token) {
1729 map_extent_buffer(right, (unsigned long)item,
1730 sizeof(struct btrfs_item),
1731 &right->map_token, &right->kaddr,
1732 &right->map_start, &right->map_len,
1733 KM_USER1);
1734 }
1735
1736 push_space = push_space - btrfs_item_size(right, item);
1737 btrfs_set_item_offset(right, item, push_space);
1738 }
1739 if (right->map_token) {
1740 unmap_extent_buffer(right, right->map_token, KM_USER1);
1741 right->map_token = NULL;
1742 }
1743
1744 btrfs_mark_buffer_dirty(left);
1745 if (right_nritems)
1746 btrfs_mark_buffer_dirty(right);
1747
1748 btrfs_item_key(right, &disk_key, 0);
1749 wret = fixup_low_keys(trans, root, path, &disk_key, 1);
1750 if (wret)
1751 ret = wret;
1752
1753 /* then fixup the leaf pointer in the path */
1754 if (path->slots[0] < push_items) {
1755 path->slots[0] += old_left_nritems;
1756 free_extent_buffer(path->nodes[0]);
1757 path->nodes[0] = left;
1758 path->slots[1] -= 1;
1759 } else {
1760 free_extent_buffer(left);
1761 path->slots[0] -= push_items;
1762 }
1763 BUG_ON(path->slots[0] < 0);
1764 return ret;
1765 }
1766
1767 /*
1768 * split the path's leaf in two, making sure there is at least data_size
1769 * available for the resulting leaf level of the path.
1770 *
1771 * returns 0 if all went well and < 0 on failure.
1772 */
1773 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1774 *root, struct btrfs_key *ins_key,
1775 struct btrfs_path *path, int data_size, int extend)
1776 {
1777 struct extent_buffer *l;
1778 u32 nritems;
1779 int mid;
1780 int slot;
1781 struct extent_buffer *right;
1782 int space_needed = data_size + sizeof(struct btrfs_item);
1783 int data_copy_size;
1784 int rt_data_off;
1785 int i;
1786 int ret = 0;
1787 int wret;
1788 int double_split;
1789 int num_doubles = 0;
1790 struct btrfs_disk_key disk_key;
1791
1792 if (extend)
1793 space_needed = data_size;
1794
1795 /* first try to make some room by pushing left and right */
1796 if (ins_key->type != BTRFS_DIR_ITEM_KEY) {
1797 wret = push_leaf_right(trans, root, path, data_size, 0);
1798 if (wret < 0) {
1799 return wret;
1800 }
1801 if (wret) {
1802 wret = push_leaf_left(trans, root, path, data_size, 0);
1803 if (wret < 0)
1804 return wret;
1805 }
1806 l = path->nodes[0];
1807
1808 /* did the pushes work? */
1809 if (btrfs_leaf_free_space(root, l) >= space_needed)
1810 return 0;
1811 }
1812
1813 if (!path->nodes[1]) {
1814 ret = insert_new_root(trans, root, path, 1);
1815 if (ret)
1816 return ret;
1817 }
1818 again:
1819 double_split = 0;
1820 l = path->nodes[0];
1821 slot = path->slots[0];
1822 nritems = btrfs_header_nritems(l);
1823 mid = (nritems + 1)/ 2;
1824
1825 right = btrfs_alloc_free_block(trans, root, root->leafsize,
1826 l->start, 0);
1827 if (IS_ERR(right))
1828 return PTR_ERR(right);
1829
1830 memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
1831 btrfs_set_header_bytenr(right, right->start);
1832 btrfs_set_header_generation(right, trans->transid);
1833 btrfs_set_header_owner(right, root->root_key.objectid);
1834 btrfs_set_header_level(right, 0);
1835 write_extent_buffer(right, root->fs_info->fsid,
1836 (unsigned long)btrfs_header_fsid(right),
1837 BTRFS_FSID_SIZE);
1838 if (mid <= slot) {
1839 if (nritems == 1 ||
1840 leaf_space_used(l, mid, nritems - mid) + space_needed >
1841 BTRFS_LEAF_DATA_SIZE(root)) {
1842 if (slot >= nritems) {
1843 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1844 btrfs_set_header_nritems(right, 0);
1845 wret = insert_ptr(trans, root, path,
1846 &disk_key, right->start,
1847 path->slots[1] + 1, 1);
1848 if (wret)
1849 ret = wret;
1850 free_extent_buffer(path->nodes[0]);
1851 path->nodes[0] = right;
1852 path->slots[0] = 0;
1853 path->slots[1] += 1;
1854 return ret;
1855 }
1856 mid = slot;
1857 if (mid != nritems &&
1858 leaf_space_used(l, mid, nritems - mid) +
1859 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
1860 double_split = 1;
1861 }
1862 }
1863 } else {
1864 if (leaf_space_used(l, 0, mid + 1) + space_needed >
1865 BTRFS_LEAF_DATA_SIZE(root)) {
1866 if (!extend && slot == 0) {
1867 btrfs_cpu_key_to_disk(&disk_key, ins_key);
1868 btrfs_set_header_nritems(right, 0);
1869 wret = insert_ptr(trans, root, path,
1870 &disk_key,
1871 right->start,
1872 path->slots[1], 1);
1873 if (wret)
1874 ret = wret;
1875 free_extent_buffer(path->nodes[0]);
1876 path->nodes[0] = right;
1877 path->slots[0] = 0;
1878 if (path->slots[1] == 0) {
1879 wret = fixup_low_keys(trans, root,
1880 path, &disk_key, 1);
1881 if (wret)
1882 ret = wret;
1883 }
1884 return ret;
1885 } else if (extend && slot == 0) {
1886 mid = 1;
1887 } else {
1888 mid = slot;
1889 if (mid != nritems &&
1890 leaf_space_used(l, mid, nritems - mid) +
1891 space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
1892 double_split = 1;
1893 }
1894 }
1895 }
1896 }
1897 nritems = nritems - mid;
1898 btrfs_set_header_nritems(right, nritems);
1899 data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
1900
1901 copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
1902 btrfs_item_nr_offset(mid),
1903 nritems * sizeof(struct btrfs_item));
1904
1905 copy_extent_buffer(right, l,
1906 btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
1907 data_copy_size, btrfs_leaf_data(l) +
1908 leaf_data_end(root, l), data_copy_size);
1909
1910 rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
1911 btrfs_item_end_nr(l, mid);
1912
1913 for (i = 0; i < nritems; i++) {
1914 struct btrfs_item *item = btrfs_item_nr(right, i);
1915 u32 ioff;
1916
1917 if (!right->map_token) {
1918 map_extent_buffer(right, (unsigned long)item,
1919 sizeof(struct btrfs_item),
1920 &right->map_token, &right->kaddr,
1921 &right->map_start, &right->map_len,
1922 KM_USER1);
1923 }
1924
1925 ioff = btrfs_item_offset(right, item);
1926 btrfs_set_item_offset(right, item, ioff + rt_data_off);
1927 }
1928
1929 if (right->map_token) {
1930 unmap_extent_buffer(right, right->map_token, KM_USER1);
1931 right->map_token = NULL;
1932 }
1933
1934 btrfs_set_header_nritems(l, mid);
1935 ret = 0;
1936 btrfs_item_key(right, &disk_key, 0);
1937 wret = insert_ptr(trans, root, path, &disk_key, right->start,
1938 path->slots[1] + 1, 1);
1939 if (wret)
1940 ret = wret;
1941
1942 btrfs_mark_buffer_dirty(right);
1943 btrfs_mark_buffer_dirty(l);
1944 BUG_ON(path->slots[0] != slot);
1945
1946 if (mid <= slot) {
1947 free_extent_buffer(path->nodes[0]);
1948 path->nodes[0] = right;
1949 path->slots[0] -= mid;
1950 path->slots[1] += 1;
1951 } else
1952 free_extent_buffer(right);
1953
1954 BUG_ON(path->slots[0] < 0);
1955
1956 if (double_split) {
1957 BUG_ON(num_doubles != 0);
1958 num_doubles++;
1959 goto again;
1960 }
1961 return ret;
1962 }
1963
1964 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
1965 struct btrfs_root *root,
1966 struct btrfs_path *path,
1967 u32 new_size, int from_end)
1968 {
1969 int ret = 0;
1970 int slot;
1971 int slot_orig;
1972 struct extent_buffer *leaf;
1973 struct btrfs_item *item;
1974 u32 nritems;
1975 unsigned int data_end;
1976 unsigned int old_data_start;
1977 unsigned int old_size;
1978 unsigned int size_diff;
1979 int i;
1980
1981 slot_orig = path->slots[0];
1982 leaf = path->nodes[0];
1983 slot = path->slots[0];
1984
1985 old_size = btrfs_item_size_nr(leaf, slot);
1986 if (old_size == new_size)
1987 return 0;
1988
1989 nritems = btrfs_header_nritems(leaf);
1990 data_end = leaf_data_end(root, leaf);
1991
1992 old_data_start = btrfs_item_offset_nr(leaf, slot);
1993
1994 size_diff = old_size - new_size;
1995
1996 BUG_ON(slot < 0);
1997 BUG_ON(slot >= nritems);
1998
1999 /*
2000 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2001 */
2002 /* first correct the data pointers */
2003 for (i = slot; i < nritems; i++) {
2004 u32 ioff;
2005 item = btrfs_item_nr(leaf, i);
2006
2007 if (!leaf->map_token) {
2008 map_extent_buffer(leaf, (unsigned long)item,
2009 sizeof(struct btrfs_item),
2010 &leaf->map_token, &leaf->kaddr,
2011 &leaf->map_start, &leaf->map_len,
2012 KM_USER1);
2013 }
2014
2015 ioff = btrfs_item_offset(leaf, item);
2016 btrfs_set_item_offset(leaf, item, ioff + size_diff);
2017 }
2018
2019 if (leaf->map_token) {
2020 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2021 leaf->map_token = NULL;
2022 }
2023
2024 /* shift the data */
2025 if (from_end) {
2026 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2027 data_end + size_diff, btrfs_leaf_data(leaf) +
2028 data_end, old_data_start + new_size - data_end);
2029 } else {
2030 struct btrfs_disk_key disk_key;
2031 u64 offset;
2032
2033 btrfs_item_key(leaf, &disk_key, slot);
2034
2035 if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
2036 unsigned long ptr;
2037 struct btrfs_file_extent_item *fi;
2038
2039 fi = btrfs_item_ptr(leaf, slot,
2040 struct btrfs_file_extent_item);
2041 fi = (struct btrfs_file_extent_item *)(
2042 (unsigned long)fi - size_diff);
2043
2044 if (btrfs_file_extent_type(leaf, fi) ==
2045 BTRFS_FILE_EXTENT_INLINE) {
2046 ptr = btrfs_item_ptr_offset(leaf, slot);
2047 memmove_extent_buffer(leaf, ptr,
2048 (unsigned long)fi,
2049 offsetof(struct btrfs_file_extent_item,
2050 disk_bytenr));
2051 }
2052 }
2053
2054 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2055 data_end + size_diff, btrfs_leaf_data(leaf) +
2056 data_end, old_data_start - data_end);
2057
2058 offset = btrfs_disk_key_offset(&disk_key);
2059 btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
2060 btrfs_set_item_key(leaf, &disk_key, slot);
2061 if (slot == 0)
2062 fixup_low_keys(trans, root, path, &disk_key, 1);
2063 }
2064
2065 item = btrfs_item_nr(leaf, slot);
2066 btrfs_set_item_size(leaf, item, new_size);
2067 btrfs_mark_buffer_dirty(leaf);
2068
2069 ret = 0;
2070 if (btrfs_leaf_free_space(root, leaf) < 0) {
2071 btrfs_print_leaf(root, leaf);
2072 BUG();
2073 }
2074 return ret;
2075 }
2076
2077 int btrfs_extend_item(struct btrfs_trans_handle *trans,
2078 struct btrfs_root *root, struct btrfs_path *path,
2079 u32 data_size)
2080 {
2081 int ret = 0;
2082 int slot;
2083 int slot_orig;
2084 struct extent_buffer *leaf;
2085 struct btrfs_item *item;
2086 u32 nritems;
2087 unsigned int data_end;
2088 unsigned int old_data;
2089 unsigned int old_size;
2090 int i;
2091
2092 slot_orig = path->slots[0];
2093 leaf = path->nodes[0];
2094
2095 nritems = btrfs_header_nritems(leaf);
2096 data_end = leaf_data_end(root, leaf);
2097
2098 if (btrfs_leaf_free_space(root, leaf) < data_size) {
2099 btrfs_print_leaf(root, leaf);
2100 BUG();
2101 }
2102 slot = path->slots[0];
2103 old_data = btrfs_item_end_nr(leaf, slot);
2104
2105 BUG_ON(slot < 0);
2106 if (slot >= nritems) {
2107 btrfs_print_leaf(root, leaf);
2108 printk("slot %d too large, nritems %d\n", slot, nritems);
2109 BUG_ON(1);
2110 }
2111
2112 /*
2113 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2114 */
2115 /* first correct the data pointers */
2116 for (i = slot; i < nritems; i++) {
2117 u32 ioff;
2118 item = btrfs_item_nr(leaf, i);
2119
2120 if (!leaf->map_token) {
2121 map_extent_buffer(leaf, (unsigned long)item,
2122 sizeof(struct btrfs_item),
2123 &leaf->map_token, &leaf->kaddr,
2124 &leaf->map_start, &leaf->map_len,
2125 KM_USER1);
2126 }
2127 ioff = btrfs_item_offset(leaf, item);
2128 btrfs_set_item_offset(leaf, item, ioff - data_size);
2129 }
2130
2131 if (leaf->map_token) {
2132 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2133 leaf->map_token = NULL;
2134 }
2135
2136 /* shift the data */
2137 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2138 data_end - data_size, btrfs_leaf_data(leaf) +
2139 data_end, old_data - data_end);
2140
2141 data_end = old_data;
2142 old_size = btrfs_item_size_nr(leaf, slot);
2143 item = btrfs_item_nr(leaf, slot);
2144 btrfs_set_item_size(leaf, item, old_size + data_size);
2145 btrfs_mark_buffer_dirty(leaf);
2146
2147 ret = 0;
2148 if (btrfs_leaf_free_space(root, leaf) < 0) {
2149 btrfs_print_leaf(root, leaf);
2150 BUG();
2151 }
2152 return ret;
2153 }
2154
2155 /*
2156 * Given a key and some data, insert an item into the tree.
2157 * This does all the path init required, making room in the tree if needed.
2158 */
2159 int btrfs_insert_empty_item(struct btrfs_trans_handle *trans,
2160 struct btrfs_root *root,
2161 struct btrfs_path *path,
2162 struct btrfs_key *cpu_key, u32 data_size)
2163 {
2164 struct extent_buffer *leaf;
2165 struct btrfs_item *item;
2166 int ret = 0;
2167 int slot;
2168 int slot_orig;
2169 u32 nritems;
2170 unsigned int data_end;
2171 struct btrfs_disk_key disk_key;
2172
2173 btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2174
2175 /* create a root if there isn't one */
2176 if (!root->node)
2177 BUG();
2178
2179 ret = btrfs_search_slot(trans, root, cpu_key, path, data_size, 1);
2180 if (ret == 0) {
2181 return -EEXIST;
2182 }
2183 if (ret < 0)
2184 goto out;
2185
2186 slot_orig = path->slots[0];
2187 leaf = path->nodes[0];
2188
2189 nritems = btrfs_header_nritems(leaf);
2190 data_end = leaf_data_end(root, leaf);
2191
2192 if (btrfs_leaf_free_space(root, leaf) <
2193 sizeof(struct btrfs_item) + data_size) {
2194 btrfs_print_leaf(root, leaf);
2195 printk("not enough freespace need %u have %d\n",
2196 data_size, btrfs_leaf_free_space(root, leaf));
2197 BUG();
2198 }
2199
2200 slot = path->slots[0];
2201 BUG_ON(slot < 0);
2202
2203 if (slot != nritems) {
2204 int i;
2205 unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2206
2207 if (old_data < data_end) {
2208 btrfs_print_leaf(root, leaf);
2209 printk("slot %d old_data %d data_end %d\n",
2210 slot, old_data, data_end);
2211 BUG_ON(1);
2212 }
2213 /*
2214 * item0..itemN ... dataN.offset..dataN.size .. data0.size
2215 */
2216 /* first correct the data pointers */
2217 WARN_ON(leaf->map_token);
2218 for (i = slot; i < nritems; i++) {
2219 u32 ioff;
2220
2221 item = btrfs_item_nr(leaf, i);
2222 if (!leaf->map_token) {
2223 map_extent_buffer(leaf, (unsigned long)item,
2224 sizeof(struct btrfs_item),
2225 &leaf->map_token, &leaf->kaddr,
2226 &leaf->map_start, &leaf->map_len,
2227 KM_USER1);
2228 }
2229
2230 ioff = btrfs_item_offset(leaf, item);
2231 btrfs_set_item_offset(leaf, item, ioff - data_size);
2232 }
2233 if (leaf->map_token) {
2234 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2235 leaf->map_token = NULL;
2236 }
2237
2238 /* shift the items */
2239 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1),
2240 btrfs_item_nr_offset(slot),
2241 (nritems - slot) * sizeof(struct btrfs_item));
2242
2243 /* shift the data */
2244 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2245 data_end - data_size, btrfs_leaf_data(leaf) +
2246 data_end, old_data - data_end);
2247 data_end = old_data;
2248 }
2249
2250 /* setup the item for the new data */
2251 btrfs_set_item_key(leaf, &disk_key, slot);
2252 item = btrfs_item_nr(leaf, slot);
2253 btrfs_set_item_offset(leaf, item, data_end - data_size);
2254 btrfs_set_item_size(leaf, item, data_size);
2255 btrfs_set_header_nritems(leaf, nritems + 1);
2256 btrfs_mark_buffer_dirty(leaf);
2257
2258 ret = 0;
2259 if (slot == 0)
2260 ret = fixup_low_keys(trans, root, path, &disk_key, 1);
2261
2262 if (btrfs_leaf_free_space(root, leaf) < 0) {
2263 btrfs_print_leaf(root, leaf);
2264 BUG();
2265 }
2266 out:
2267 return ret;
2268 }
2269
2270 /*
2271 * Given a key and some data, insert an item into the tree.
2272 * This does all the path init required, making room in the tree if needed.
2273 */
2274 int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
2275 *root, struct btrfs_key *cpu_key, void *data, u32
2276 data_size)
2277 {
2278 int ret = 0;
2279 struct btrfs_path *path;
2280 struct extent_buffer *leaf;
2281 unsigned long ptr;
2282
2283 path = btrfs_alloc_path();
2284 BUG_ON(!path);
2285 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2286 if (!ret) {
2287 leaf = path->nodes[0];
2288 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
2289 write_extent_buffer(leaf, data, ptr, data_size);
2290 btrfs_mark_buffer_dirty(leaf);
2291 }
2292 btrfs_free_path(path);
2293 return ret;
2294 }
2295
2296 /*
2297 * delete the pointer from a given node.
2298 *
2299 * If the delete empties a node, the node is removed from the tree,
2300 * continuing all the way the root if required. The root is converted into
2301 * a leaf if all the nodes are emptied.
2302 */
2303 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2304 struct btrfs_path *path, int level, int slot)
2305 {
2306 struct extent_buffer *parent = path->nodes[level];
2307 u32 nritems;
2308 int ret = 0;
2309 int wret;
2310
2311 nritems = btrfs_header_nritems(parent);
2312 if (slot != nritems -1) {
2313 memmove_extent_buffer(parent,
2314 btrfs_node_key_ptr_offset(slot),
2315 btrfs_node_key_ptr_offset(slot + 1),
2316 sizeof(struct btrfs_key_ptr) *
2317 (nritems - slot - 1));
2318 }
2319 nritems--;
2320 btrfs_set_header_nritems(parent, nritems);
2321 if (nritems == 0 && parent == root->node) {
2322 BUG_ON(btrfs_header_level(root->node) != 1);
2323 /* just turn the root into a leaf and break */
2324 btrfs_set_header_level(root->node, 0);
2325 } else if (slot == 0) {
2326 struct btrfs_disk_key disk_key;
2327
2328 btrfs_node_key(parent, &disk_key, 0);
2329 wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
2330 if (wret)
2331 ret = wret;
2332 }
2333 btrfs_mark_buffer_dirty(parent);
2334 return ret;
2335 }
2336
2337 /*
2338 * delete the item at the leaf level in path. If that empties
2339 * the leaf, remove it from the tree
2340 */
2341 int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2342 struct btrfs_path *path)
2343 {
2344 int slot;
2345 struct extent_buffer *leaf;
2346 struct btrfs_item *item;
2347 int doff;
2348 int dsize;
2349 int ret = 0;
2350 int wret;
2351 u32 nritems;
2352
2353 leaf = path->nodes[0];
2354 slot = path->slots[0];
2355 doff = btrfs_item_offset_nr(leaf, slot);
2356 dsize = btrfs_item_size_nr(leaf, slot);
2357 nritems = btrfs_header_nritems(leaf);
2358
2359 if (slot != nritems - 1) {
2360 int i;
2361 int data_end = leaf_data_end(root, leaf);
2362
2363 memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2364 data_end + dsize,
2365 btrfs_leaf_data(leaf) + data_end,
2366 doff - data_end);
2367
2368 for (i = slot + 1; i < nritems; i++) {
2369 u32 ioff;
2370
2371 item = btrfs_item_nr(leaf, i);
2372 if (!leaf->map_token) {
2373 map_extent_buffer(leaf, (unsigned long)item,
2374 sizeof(struct btrfs_item),
2375 &leaf->map_token, &leaf->kaddr,
2376 &leaf->map_start, &leaf->map_len,
2377 KM_USER1);
2378 }
2379 ioff = btrfs_item_offset(leaf, item);
2380 btrfs_set_item_offset(leaf, item, ioff + dsize);
2381 }
2382
2383 if (leaf->map_token) {
2384 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2385 leaf->map_token = NULL;
2386 }
2387
2388 memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
2389 btrfs_item_nr_offset(slot + 1),
2390 sizeof(struct btrfs_item) *
2391 (nritems - slot - 1));
2392 }
2393 btrfs_set_header_nritems(leaf, nritems - 1);
2394 nritems--;
2395
2396 /* delete the leaf if we've emptied it */
2397 if (nritems == 0) {
2398 if (leaf == root->node) {
2399 btrfs_set_header_level(leaf, 0);
2400 } else {
2401 clean_tree_block(trans, root, leaf);
2402 wait_on_tree_block_writeback(root, leaf);
2403 wret = del_ptr(trans, root, path, 1, path->slots[1]);
2404 if (wret)
2405 ret = wret;
2406 wret = btrfs_free_extent(trans, root,
2407 leaf->start, leaf->len, 1);
2408 if (wret)
2409 ret = wret;
2410 }
2411 } else {
2412 int used = leaf_space_used(leaf, 0, nritems);
2413 if (slot == 0) {
2414 struct btrfs_disk_key disk_key;
2415
2416 btrfs_item_key(leaf, &disk_key, 0);
2417 wret = fixup_low_keys(trans, root, path,
2418 &disk_key, 1);
2419 if (wret)
2420 ret = wret;
2421 }
2422
2423 /* delete the leaf if it is mostly empty */
2424 if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) {
2425 /* push_leaf_left fixes the path.
2426 * make sure the path still points to our leaf
2427 * for possible call to del_ptr below
2428 */
2429 slot = path->slots[1];
2430 extent_buffer_get(leaf);
2431
2432 wret = push_leaf_right(trans, root, path, 1, 1);
2433 if (wret < 0 && wret != -ENOSPC)
2434 ret = wret;
2435
2436 if (path->nodes[0] == leaf &&
2437 btrfs_header_nritems(leaf)) {
2438 wret = push_leaf_left(trans, root, path, 1, 1);
2439 if (wret < 0 && wret != -ENOSPC)
2440 ret = wret;
2441 }
2442
2443 if (btrfs_header_nritems(leaf) == 0) {
2444 u64 bytenr = leaf->start;
2445 u32 blocksize = leaf->len;
2446
2447 clean_tree_block(trans, root, leaf);
2448 wait_on_tree_block_writeback(root, leaf);
2449
2450 wret = del_ptr(trans, root, path, 1, slot);
2451 if (wret)
2452 ret = wret;
2453
2454 free_extent_buffer(leaf);
2455 wret = btrfs_free_extent(trans, root, bytenr,
2456 blocksize, 1);
2457 if (wret)
2458 ret = wret;
2459 } else {
2460 btrfs_mark_buffer_dirty(leaf);
2461 free_extent_buffer(leaf);
2462 }
2463 } else {
2464 btrfs_mark_buffer_dirty(leaf);
2465 }
2466 }
2467 return ret;
2468 }
2469
2470 /*
2471 * walk up the tree as far as required to find the next leaf.
2472 * returns 0 if it found something or 1 if there are no greater leaves.
2473 * returns < 0 on io errors.
2474 */
2475 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2476 {
2477 int slot;
2478 int level = 1;
2479 u64 bytenr;
2480 struct extent_buffer *c;
2481 struct extent_buffer *next = NULL;
2482
2483 while(level < BTRFS_MAX_LEVEL) {
2484 if (!path->nodes[level])
2485 return 1;
2486
2487 slot = path->slots[level] + 1;
2488 c = path->nodes[level];
2489 if (slot >= btrfs_header_nritems(c)) {
2490 level++;
2491 continue;
2492 }
2493
2494 bytenr = btrfs_node_blockptr(c, slot);
2495 if (next)
2496 free_extent_buffer(next);
2497
2498 if (path->reada)
2499 reada_for_search(root, path, level, slot);
2500
2501 next = read_tree_block(root, bytenr,
2502 btrfs_level_size(root, level -1));
2503 break;
2504 }
2505 path->slots[level] = slot;
2506 while(1) {
2507 level--;
2508 c = path->nodes[level];
2509 free_extent_buffer(c);
2510 path->nodes[level] = next;
2511 path->slots[level] = 0;
2512 if (!level)
2513 break;
2514 if (path->reada)
2515 reada_for_search(root, path, level, 0);
2516 next = read_tree_block(root, btrfs_node_blockptr(next, 0),
2517 btrfs_level_size(root, level - 1));
2518 }
2519 return 0;
2520 }
Linux kernel - Deliverables
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