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