ctree.c 63.4 KB
Newer Older
C
Chris Mason 已提交
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
/*
 * Copyright (C) 2007 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

19
#include <linux/highmem.h>
20 21
#include "ctree.h"
#include "disk-io.h"
22
#include "transaction.h"
23
#include "print-tree.h"
24

25 26 27
static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
		      *root, struct btrfs_path *path, int level);
static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
28 29
		      *root, struct btrfs_key *ins_key,
		      struct btrfs_path *path, int data_size);
30 31 32 33 34 35 36
static int push_node_left(struct btrfs_trans_handle *trans,
			  struct btrfs_root *root, struct extent_buffer *dst,
			  struct extent_buffer *src);
static int balance_node_right(struct btrfs_trans_handle *trans,
			      struct btrfs_root *root,
			      struct extent_buffer *dst_buf,
			      struct extent_buffer *src_buf);
37 38
static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
		   struct btrfs_path *path, int level, int slot);
39

C
Chris Mason 已提交
40
inline void btrfs_init_path(struct btrfs_path *p)
C
Chris Mason 已提交
41
{
C
Chris Mason 已提交
42
	memset(p, 0, sizeof(*p));
C
Chris Mason 已提交
43 44
}

C
Chris Mason 已提交
45
struct btrfs_path *btrfs_alloc_path(void)
C
Chris Mason 已提交
46
{
C
Chris Mason 已提交
47 48
	struct btrfs_path *path;
	path = kmem_cache_alloc(btrfs_path_cachep, GFP_NOFS);
49
	if (path) {
C
Chris Mason 已提交
50
		btrfs_init_path(path);
51 52
		path->reada = 1;
	}
C
Chris Mason 已提交
53
	return path;
C
Chris Mason 已提交
54 55
}

C
Chris Mason 已提交
56
void btrfs_free_path(struct btrfs_path *p)
57
{
C
Chris Mason 已提交
58 59
	btrfs_release_path(NULL, p);
	kmem_cache_free(btrfs_path_cachep, p);
60 61
}

C
Chris Mason 已提交
62
void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
63 64
{
	int i;
C
Chris Mason 已提交
65
	for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
66 67
		if (!p->nodes[i])
			break;
68
		free_extent_buffer(p->nodes[i]);
69
	}
C
Chris Mason 已提交
70
	memset(p, 0, sizeof(*p));
71 72
}

73 74 75 76 77 78
static int __btrfs_cow_block(struct btrfs_trans_handle *trans,
			     struct btrfs_root *root,
			     struct extent_buffer *buf,
			     struct extent_buffer *parent, int parent_slot,
			     struct extent_buffer **cow_ret,
			     u64 search_start, u64 empty_size)
C
Chris Mason 已提交
79
{
80
	struct extent_buffer *cow;
81 82
	int ret = 0;
	int different_trans = 0;
C
Chris Mason 已提交
83

84
	WARN_ON(root->ref_cows && trans->transid != root->last_trans);
85

86 87
	cow = btrfs_alloc_free_block(trans, root, buf->len,
				     search_start, empty_size);
88 89
	if (IS_ERR(cow))
		return PTR_ERR(cow);
90

91
	copy_extent_buffer(cow, buf, 0, 0, cow->len);
92
	btrfs_set_header_bytenr(cow, cow->start);
93 94
	btrfs_set_header_generation(cow, trans->transid);
	btrfs_set_header_owner(cow, root->root_key.objectid);
95

96 97
	WARN_ON(btrfs_header_generation(buf) > trans->transid);
	if (btrfs_header_generation(buf) != trans->transid) {
98 99 100 101 102 103 104 105
		different_trans = 1;
		ret = btrfs_inc_ref(trans, root, buf);
		if (ret)
			return ret;
	} else {
		clean_tree_block(trans, root, buf);
	}

C
Chris Mason 已提交
106 107
	if (buf == root->node) {
		root->node = cow;
108
		extent_buffer_get(cow);
C
Chris Mason 已提交
109
		if (buf != root->commit_root) {
110 111
			btrfs_free_extent(trans, root, buf->start,
					  buf->len, 1);
C
Chris Mason 已提交
112
		}
113
		free_extent_buffer(buf);
C
Chris Mason 已提交
114
	} else {
115
		btrfs_set_node_blockptr(parent, parent_slot,
116
					cow->start);
C
Chris Mason 已提交
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);
C
Chris Mason 已提交
120
	}
121
	free_extent_buffer(buf);
C
Chris Mason 已提交
122
	btrfs_mark_buffer_dirty(cow);
C
Chris Mason 已提交
123
	*cow_ret = cow;
C
Chris Mason 已提交
124 125 126
	return 0;
}

127 128 129 130
int btrfs_cow_block(struct btrfs_trans_handle *trans,
		    struct btrfs_root *root, struct extent_buffer *buf,
		    struct extent_buffer *parent, int parent_slot,
		    struct extent_buffer **cow_ret)
131 132
{
	u64 search_start;
133
	int ret;
134 135 136 137 138 139 140 141 142 143
	if (trans->transaction != root->fs_info->running_transaction) {
		printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
		       root->fs_info->running_transaction->transid);
		WARN_ON(1);
	}
	if (trans->transid != root->fs_info->generation) {
		printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
		       root->fs_info->generation);
		WARN_ON(1);
	}
144
	if (btrfs_header_generation(buf) == trans->transid) {
145 146 147 148
		*cow_ret = buf;
		return 0;
	}

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)
160 161 162 163
		return 1;
	return 0;
}

164
static int should_defrag_leaf(struct extent_buffer *leaf)
165
{
166
	struct btrfs_key key;
167 168
	u32 nritems;

169
	if (btrfs_buffer_defrag(leaf))
170 171
		return 1;

172
	nritems = btrfs_header_nritems(leaf);
173 174 175
	if (nritems == 0)
		return 0;

176 177
	btrfs_item_key_to_cpu(leaf, &key, 0);
	if (key.type == BTRFS_DIR_ITEM_KEY)
178 179
		return 1;

180 181 182

	btrfs_item_key_to_cpu(leaf, &key, nritems - 1);
	if (key.type == BTRFS_DIR_ITEM_KEY)
183 184
		return 1;
	if (nritems > 4) {
185 186
		btrfs_item_key_to_cpu(leaf, &key, nritems / 2);
		if (key.type == BTRFS_DIR_ITEM_KEY)
187 188 189 190 191
			return 1;
	}
	return 0;
}

192
int btrfs_realloc_node(struct btrfs_trans_handle *trans,
193
		       struct btrfs_root *root, struct extent_buffer *parent,
194
		       int cache_only, u64 *last_ret)
195
{
196 197
	struct extent_buffer *cur;
	struct extent_buffer *tmp;
198
	u64 blocknr;
199 200
	u64 search_start = *last_ret;
	u64 last_block = 0;
201 202 203 204 205 206
	u64 other;
	u32 parent_nritems;
	int start_slot;
	int end_slot;
	int i;
	int err = 0;
207
	int parent_level;
208 209
	int uptodate;
	u32 blocksize;
210 211 212 213 214 215 216 217 218 219 220

	if (trans->transaction != root->fs_info->running_transaction) {
		printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
		       root->fs_info->running_transaction->transid);
		WARN_ON(1);
	}
	if (trans->transid != root->fs_info->generation) {
		printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
		       root->fs_info->generation);
		WARN_ON(1);
	}
221
	if (btrfs_buffer_defrag_done(parent))
222 223
		return 0;

224 225 226
	parent_nritems = btrfs_header_nritems(parent);
	parent_level = btrfs_header_level(parent);
	blocksize = btrfs_level_size(root, parent_level - 1);
227 228 229 230 231 232 233 234 235

	start_slot = 0;
	end_slot = parent_nritems;

	if (parent_nritems == 1)
		return 0;

	for (i = start_slot; i < end_slot; i++) {
		int close = 1;
236
		blocknr = btrfs_node_blockptr(parent, i);
237 238
		if (last_block == 0)
			last_block = blocknr;
239
		if (i > 0) {
240 241
			other = btrfs_node_blockptr(parent, i - 1);
			close = close_blocks(blocknr, other, blocksize);
242 243
		}
		if (close && i < end_slot - 1) {
244 245
			other = btrfs_node_blockptr(parent, i + 1);
			close = close_blocks(blocknr, other, blocksize);
246
		}
247 248
		if (close) {
			last_block = blocknr;
249
			continue;
250
		}
251

252 253 254 255 256 257 258 259
		cur = btrfs_find_tree_block(root, blocknr, blocksize);
		if (cur)
			uptodate = btrfs_buffer_uptodate(cur);
		else
			uptodate = 0;
		if (!cur || !uptodate ||
		    (parent_level != 1 && !btrfs_buffer_defrag(cur)) ||
		    (parent_level == 1 && !should_defrag_leaf(cur))) {
260
			if (cache_only) {
261
				free_extent_buffer(cur);
262 263
				continue;
			}
264 265 266 267 268
			if (!cur) {
				cur = read_tree_block(root, blocknr,
							 blocksize);
			} else if (!uptodate) {
				btrfs_read_buffer(cur);
269
			}
270
		}
271
		if (search_start == 0)
272
			search_start = last_block;
273

274 275 276 277
		err = __btrfs_cow_block(trans, root, cur, parent, i,
					&tmp, search_start,
					min(16 * blocksize,
					    (end_slot - i) * blocksize));
Y
Yan 已提交
278
		if (err) {
279
			free_extent_buffer(cur);
280
			break;
Y
Yan 已提交
281
		}
282
		search_start = tmp->start;
283 284
		*last_ret = search_start;
		if (parent_level == 1)
285 286 287
			btrfs_clear_buffer_defrag(tmp);
		btrfs_set_buffer_defrag_done(tmp);
		free_extent_buffer(tmp);
288 289 290 291
	}
	return err;
}

C
Chris Mason 已提交
292 293 294 295 296
/*
 * The leaf data grows from end-to-front in the node.
 * this returns the address of the start of the last item,
 * which is the stop of the leaf data stack
 */
C
Chris Mason 已提交
297
static inline unsigned int leaf_data_end(struct btrfs_root *root,
298
					 struct extent_buffer *leaf)
299
{
300
	u32 nr = btrfs_header_nritems(leaf);
301
	if (nr == 0)
C
Chris Mason 已提交
302
		return BTRFS_LEAF_DATA_SIZE(root);
303
	return btrfs_item_offset_nr(leaf, nr - 1);
304 305
}

C
Chris Mason 已提交
306 307 308
/*
 * compare two keys in a memcmp fashion
 */
C
Chris Mason 已提交
309
static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
310
{
C
Chris Mason 已提交
311 312 313 314 315
	struct btrfs_key k1;

	btrfs_disk_key_to_cpu(&k1, disk);

	if (k1.objectid > k2->objectid)
316
		return 1;
C
Chris Mason 已提交
317
	if (k1.objectid < k2->objectid)
318
		return -1;
319
	if (k1.type > k2->type)
C
Chris Mason 已提交
320
		return 1;
321
	if (k1.type < k2->type)
C
Chris Mason 已提交
322
		return -1;
323 324 325 326
	if (k1.offset > k2->offset)
		return 1;
	if (k1.offset < k2->offset)
		return -1;
327 328
	return 0;
}
C
Chris Mason 已提交
329

C
Chris Mason 已提交
330 331
static int check_node(struct btrfs_root *root, struct btrfs_path *path,
		      int level)
C
Chris Mason 已提交
332
{
333 334 335 336
	struct extent_buffer *parent = NULL;
	struct extent_buffer *node = path->nodes[level];
	struct btrfs_disk_key parent_key;
	struct btrfs_disk_key node_key;
C
Chris Mason 已提交
337
	int parent_slot;
338 339
	int slot;
	struct btrfs_key cpukey;
340
	u32 nritems = btrfs_header_nritems(node);
C
Chris Mason 已提交
341 342

	if (path->nodes[level + 1])
343
		parent = path->nodes[level + 1];
A
Aneesh 已提交
344

345
	slot = path->slots[level];
346 347
	BUG_ON(nritems == 0);
	if (parent) {
A
Aneesh 已提交
348
		parent_slot = path->slots[level + 1];
349 350 351
		btrfs_node_key(parent, &parent_key, parent_slot);
		btrfs_node_key(node, &node_key, 0);
		BUG_ON(memcmp(&parent_key, &node_key,
C
Chris Mason 已提交
352
			      sizeof(struct btrfs_disk_key)));
353
		BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
354
		       btrfs_header_bytenr(node));
C
Chris Mason 已提交
355
	}
C
Chris Mason 已提交
356
	BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root));
357
	if (slot != 0) {
358 359 360
		btrfs_node_key_to_cpu(node, &cpukey, slot - 1);
		btrfs_node_key(node, &node_key, slot);
		BUG_ON(comp_keys(&node_key, &cpukey) <= 0);
361 362
	}
	if (slot < nritems - 1) {
363 364 365
		btrfs_node_key_to_cpu(node, &cpukey, slot + 1);
		btrfs_node_key(node, &node_key, slot);
		BUG_ON(comp_keys(&node_key, &cpukey) >= 0);
C
Chris Mason 已提交
366 367 368 369
	}
	return 0;
}

C
Chris Mason 已提交
370 371
static int check_leaf(struct btrfs_root *root, struct btrfs_path *path,
		      int level)
C
Chris Mason 已提交
372
{
373 374
	struct extent_buffer *leaf = path->nodes[level];
	struct extent_buffer *parent = NULL;
C
Chris Mason 已提交
375
	int parent_slot;
376
	struct btrfs_key cpukey;
377 378 379
	struct btrfs_disk_key parent_key;
	struct btrfs_disk_key leaf_key;
	int slot = path->slots[0];
380

381
	u32 nritems = btrfs_header_nritems(leaf);
C
Chris Mason 已提交
382 383

	if (path->nodes[level + 1])
384
		parent = path->nodes[level + 1];
385 386 387 388 389

	if (nritems == 0)
		return 0;

	if (parent) {
A
Aneesh 已提交
390
		parent_slot = path->slots[level + 1];
391 392
		btrfs_node_key(parent, &parent_key, parent_slot);
		btrfs_item_key(leaf, &leaf_key, 0);
393

394
		BUG_ON(memcmp(&parent_key, &leaf_key,
C
Chris Mason 已提交
395
		       sizeof(struct btrfs_disk_key)));
396
		BUG_ON(btrfs_node_blockptr(parent, parent_slot) !=
397
		       btrfs_header_bytenr(leaf));
398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422
	}
#if 0
	for (i = 0; nritems > 1 && i < nritems - 2; i++) {
		btrfs_item_key_to_cpu(leaf, &cpukey, i + 1);
		btrfs_item_key(leaf, &leaf_key, i);
		if (comp_keys(&leaf_key, &cpukey) >= 0) {
			btrfs_print_leaf(root, leaf);
			printk("slot %d offset bad key\n", i);
			BUG_ON(1);
		}
		if (btrfs_item_offset_nr(leaf, i) !=
			btrfs_item_end_nr(leaf, i + 1)) {
			btrfs_print_leaf(root, leaf);
			printk("slot %d offset bad\n", i);
			BUG_ON(1);
		}
		if (i == 0) {
			if (btrfs_item_offset_nr(leaf, i) +
			       btrfs_item_size_nr(leaf, i) !=
			       BTRFS_LEAF_DATA_SIZE(root)) {
				btrfs_print_leaf(root, leaf);
				printk("slot %d first offset bad\n", i);
				BUG_ON(1);
			}
		}
C
Chris Mason 已提交
423
	}
424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445
	if (nritems > 0) {
		if (btrfs_item_size_nr(leaf, nritems - 1) > 4096) {
				btrfs_print_leaf(root, leaf);
				printk("slot %d bad size \n", nritems - 1);
				BUG_ON(1);
		}
	}
#endif
	if (slot != 0 && slot < nritems - 1) {
		btrfs_item_key(leaf, &leaf_key, slot);
		btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1);
		if (comp_keys(&leaf_key, &cpukey) <= 0) {
			btrfs_print_leaf(root, leaf);
			printk("slot %d offset bad key\n", slot);
			BUG_ON(1);
		}
		if (btrfs_item_offset_nr(leaf, slot - 1) !=
		       btrfs_item_end_nr(leaf, slot)) {
			btrfs_print_leaf(root, leaf);
			printk("slot %d offset bad\n", slot);
			BUG_ON(1);
		}
446 447
	}
	if (slot < nritems - 1) {
448 449 450 451 452 453 454 455 456
		btrfs_item_key(leaf, &leaf_key, slot);
		btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1);
		BUG_ON(comp_keys(&leaf_key, &cpukey) >= 0);
		if (btrfs_item_offset_nr(leaf, slot) !=
			btrfs_item_end_nr(leaf, slot + 1)) {
			btrfs_print_leaf(root, leaf);
			printk("slot %d offset bad\n", slot);
			BUG_ON(1);
		}
C
Chris Mason 已提交
457
	}
458 459
	BUG_ON(btrfs_item_offset_nr(leaf, 0) +
	       btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root));
C
Chris Mason 已提交
460 461 462
	return 0;
}

C
Chris Mason 已提交
463 464
static int check_block(struct btrfs_root *root, struct btrfs_path *path,
			int level)
C
Chris Mason 已提交
465
{
466
#if 0
467 468
	struct extent_buffer *buf = path->nodes[level];

469 470 471
	if (memcmp_extent_buffer(buf, root->fs_info->fsid,
				 (unsigned long)btrfs_header_fsid(buf),
				 BTRFS_FSID_SIZE)) {
472
		printk("warning bad block %Lu\n", buf->start);
473
		return 1;
474
	}
475
#endif
C
Chris Mason 已提交
476
	if (level == 0)
C
Chris Mason 已提交
477 478
		return check_leaf(root, path, level);
	return check_node(root, path, level);
C
Chris Mason 已提交
479 480
}

C
Chris Mason 已提交
481
/*
482 483 484
 * search for key in the extent_buffer.  The items start at offset p,
 * and they are item_size apart.  There are 'max' items in p.
 *
C
Chris Mason 已提交
485 486 487 488 489 490
 * the slot in the array is returned via slot, and it points to
 * the place where you would insert key if it is not found in
 * the array.
 *
 * slot may point to max if the key is bigger than all of the keys
 */
491 492 493
static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
			      int item_size, struct btrfs_key *key,
			      int max, int *slot)
494 495 496 497 498
{
	int low = 0;
	int high = max;
	int mid;
	int ret;
499
	struct btrfs_disk_key *tmp = NULL;
500 501 502 503 504 505
	struct btrfs_disk_key unaligned;
	unsigned long offset;
	char *map_token = NULL;
	char *kaddr = NULL;
	unsigned long map_start = 0;
	unsigned long map_len = 0;
506
	int err;
507 508 509

	while(low < high) {
		mid = (low + high) / 2;
510 511 512 513 514
		offset = p + mid * item_size;

		if (!map_token || offset < map_start ||
		    (offset + sizeof(struct btrfs_disk_key)) >
		    map_start + map_len) {
515
			if (map_token) {
516
				unmap_extent_buffer(eb, map_token, KM_USER0);
517 518 519 520 521 522 523 524 525 526 527 528 529 530 531
				map_token = NULL;
			}
			err = map_extent_buffer(eb, offset,
						sizeof(struct btrfs_disk_key),
						&map_token, &kaddr,
						&map_start, &map_len, KM_USER0);

			if (!err) {
				tmp = (struct btrfs_disk_key *)(kaddr + offset -
							map_start);
			} else {
				read_extent_buffer(eb, &unaligned,
						   offset, sizeof(unaligned));
				tmp = &unaligned;
			}
532 533 534 535 536

		} else {
			tmp = (struct btrfs_disk_key *)(kaddr + offset -
							map_start);
		}
537 538 539 540 541 542 543 544
		ret = comp_keys(tmp, key);

		if (ret < 0)
			low = mid + 1;
		else if (ret > 0)
			high = mid;
		else {
			*slot = mid;
545 546
			if (map_token)
				unmap_extent_buffer(eb, map_token, KM_USER0);
547 548 549 550
			return 0;
		}
	}
	*slot = low;
551 552
	if (map_token)
		unmap_extent_buffer(eb, map_token, KM_USER0);
553 554 555
	return 1;
}

C
Chris Mason 已提交
556 557 558 559
/*
 * simple bin_search frontend that does the right thing for
 * leaves vs nodes
 */
560 561
static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
		      int level, int *slot)
562
{
563 564 565
	if (level == 0) {
		return generic_bin_search(eb,
					  offsetof(struct btrfs_leaf, items),
C
Chris Mason 已提交
566
					  sizeof(struct btrfs_item),
567
					  key, btrfs_header_nritems(eb),
568
					  slot);
569
	} else {
570 571
		return generic_bin_search(eb,
					  offsetof(struct btrfs_node, ptrs),
C
Chris Mason 已提交
572
					  sizeof(struct btrfs_key_ptr),
573
					  key, btrfs_header_nritems(eb),
574
					  slot);
575 576 577 578
	}
	return -1;
}

579 580
static struct extent_buffer *read_node_slot(struct btrfs_root *root,
				   struct extent_buffer *parent, int slot)
581 582 583
{
	if (slot < 0)
		return NULL;
584
	if (slot >= btrfs_header_nritems(parent))
585
		return NULL;
586 587
	return read_tree_block(root, btrfs_node_blockptr(parent, slot),
		       btrfs_level_size(root, btrfs_header_level(parent) - 1));
588 589
}

590 591
static int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root
			 *root, struct btrfs_path *path, int level)
592
{
593 594 595 596
	struct extent_buffer *right = NULL;
	struct extent_buffer *mid;
	struct extent_buffer *left = NULL;
	struct extent_buffer *parent = NULL;
597 598 599 600
	int ret = 0;
	int wret;
	int pslot;
	int orig_slot = path->slots[level];
601
	int err_on_enospc = 0;
602
	u64 orig_ptr;
603 604 605 606

	if (level == 0)
		return 0;

607
	mid = path->nodes[level];
608
	orig_ptr = btrfs_node_blockptr(mid, orig_slot);
609

C
Chris Mason 已提交
610
	if (level < BTRFS_MAX_LEVEL - 1)
611
		parent = path->nodes[level + 1];
612 613
	pslot = path->slots[level + 1];

C
Chris Mason 已提交
614 615 616 617
	/*
	 * deal with the case where there is only one pointer in the root
	 * by promoting the node below to a root
	 */
618 619
	if (!parent) {
		struct extent_buffer *child;
620

621
		if (btrfs_header_nritems(mid) != 1)
622 623 624
			return 0;

		/* promote the child to a root */
625
		child = read_node_slot(root, mid, 0);
626 627 628
		BUG_ON(!child);
		root->node = child;
		path->nodes[level] = NULL;
629 630
		clean_tree_block(trans, root, mid);
		wait_on_tree_block_writeback(root, mid);
631
		/* once for the path */
632
		free_extent_buffer(mid);
633
		ret = btrfs_free_extent(trans, root, mid->start, mid->len, 1);
634
		/* once for the root ptr */
635
		free_extent_buffer(mid);
636
		return ret;
637
	}
638
	if (btrfs_header_nritems(mid) >
C
Chris Mason 已提交
639
	    BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
640 641
		return 0;

642
	if (btrfs_header_nritems(mid) < 2)
643 644
		err_on_enospc = 1;

645 646 647 648
	left = read_node_slot(root, parent, pslot - 1);
	if (left) {
		wret = btrfs_cow_block(trans, root, left,
				       parent, pslot - 1, &left);
649 650 651 652
		if (wret) {
			ret = wret;
			goto enospc;
		}
653
	}
654 655 656 657
	right = read_node_slot(root, parent, pslot + 1);
	if (right) {
		wret = btrfs_cow_block(trans, root, right,
				       parent, pslot + 1, &right);
658 659 660 661 662 663 664
		if (wret) {
			ret = wret;
			goto enospc;
		}
	}

	/* first, try to make some room in the middle buffer */
665 666 667
	if (left) {
		orig_slot += btrfs_header_nritems(left);
		wret = push_node_left(trans, root, left, mid);
668 669
		if (wret < 0)
			ret = wret;
670
		if (btrfs_header_nritems(mid) < 2)
671
			err_on_enospc = 1;
672
	}
673 674 675 676

	/*
	 * then try to empty the right most buffer into the middle
	 */
677 678
	if (right) {
		wret = push_node_left(trans, root, mid, right);
679
		if (wret < 0 && wret != -ENOSPC)
680
			ret = wret;
681
		if (btrfs_header_nritems(right) == 0) {
682 683 684
			u64 bytenr = right->start;
			u32 blocksize = right->len;

685 686 687
			clean_tree_block(trans, root, right);
			wait_on_tree_block_writeback(root, right);
			free_extent_buffer(right);
688
			right = NULL;
689 690
			wret = del_ptr(trans, root, path, level + 1, pslot +
				       1);
691 692
			if (wret)
				ret = wret;
693 694
			wret = btrfs_free_extent(trans, root, bytenr,
						 blocksize, 1);
695 696 697
			if (wret)
				ret = wret;
		} else {
698 699 700 701
			struct btrfs_disk_key right_key;
			btrfs_node_key(right, &right_key, 0);
			btrfs_set_node_key(parent, &right_key, pslot + 1);
			btrfs_mark_buffer_dirty(parent);
702 703
		}
	}
704
	if (btrfs_header_nritems(mid) == 1) {
705 706 707 708 709 710 711 712 713
		/*
		 * we're not allowed to leave a node with one item in the
		 * tree during a delete.  A deletion from lower in the tree
		 * could try to delete the only pointer in this node.
		 * So, pull some keys from the left.
		 * There has to be a left pointer at this point because
		 * otherwise we would have pulled some pointers from the
		 * right
		 */
714 715
		BUG_ON(!left);
		wret = balance_node_right(trans, root, mid, left);
716
		if (wret < 0) {
717
			ret = wret;
718 719
			goto enospc;
		}
720 721
		BUG_ON(wret == 1);
	}
722
	if (btrfs_header_nritems(mid) == 0) {
723
		/* we've managed to empty the middle node, drop it */
724 725
		u64 bytenr = mid->start;
		u32 blocksize = mid->len;
726 727 728
		clean_tree_block(trans, root, mid);
		wait_on_tree_block_writeback(root, mid);
		free_extent_buffer(mid);
729
		mid = NULL;
730
		wret = del_ptr(trans, root, path, level + 1, pslot);
731 732
		if (wret)
			ret = wret;
733
		wret = btrfs_free_extent(trans, root, bytenr, blocksize, 1);
734 735
		if (wret)
			ret = wret;
736 737
	} else {
		/* update the parent key to reflect our changes */
738 739 740 741
		struct btrfs_disk_key mid_key;
		btrfs_node_key(mid, &mid_key, 0);
		btrfs_set_node_key(parent, &mid_key, pslot);
		btrfs_mark_buffer_dirty(parent);
742
	}
743

744
	/* update the path */
745 746 747 748
	if (left) {
		if (btrfs_header_nritems(left) > orig_slot) {
			extent_buffer_get(left);
			path->nodes[level] = left;
749 750
			path->slots[level + 1] -= 1;
			path->slots[level] = orig_slot;
751 752
			if (mid)
				free_extent_buffer(mid);
753
		} else {
754
			orig_slot -= btrfs_header_nritems(left);
755 756 757
			path->slots[level] = orig_slot;
		}
	}
758
	/* double check we haven't messed things up */
C
Chris Mason 已提交
759
	check_block(root, path, level);
C
Chris Mason 已提交
760
	if (orig_ptr !=
761
	    btrfs_node_blockptr(path->nodes[level], path->slots[level]))
762
		BUG();
763
enospc:
764 765 766 767
	if (right)
		free_extent_buffer(right);
	if (left)
		free_extent_buffer(left);
768 769 770
	return ret;
}

771 772 773 774 775
/* returns zero if the push worked, non-zero otherwise */
static int push_nodes_for_insert(struct btrfs_trans_handle *trans,
				struct btrfs_root *root,
				struct btrfs_path *path, int level)
{
776 777 778 779
	struct extent_buffer *right = NULL;
	struct extent_buffer *mid;
	struct extent_buffer *left = NULL;
	struct extent_buffer *parent = NULL;
780 781 782 783 784 785 786 787 788
	int ret = 0;
	int wret;
	int pslot;
	int orig_slot = path->slots[level];
	u64 orig_ptr;

	if (level == 0)
		return 1;

789
	mid = path->nodes[level];
790 791 792
	orig_ptr = btrfs_node_blockptr(mid, orig_slot);

	if (level < BTRFS_MAX_LEVEL - 1)
793
		parent = path->nodes[level + 1];
794 795
	pslot = path->slots[level + 1];

796
	if (!parent)
797 798
		return 1;

799
	left = read_node_slot(root, parent, pslot - 1);
800 801

	/* first, try to make some room in the middle buffer */
802
	if (left) {
803
		u32 left_nr;
804
		left_nr = btrfs_header_nritems(left);
C
Chris Mason 已提交
805 806 807
		if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
			wret = 1;
		} else {
808 809
			ret = btrfs_cow_block(trans, root, left, parent,
					      pslot - 1, &left);
810 811 812 813
			if (ret)
				wret = 1;
			else {
				wret = push_node_left(trans, root,
814
						      left, mid);
815
			}
C
Chris Mason 已提交
816
		}
817 818 819
		if (wret < 0)
			ret = wret;
		if (wret == 0) {
820
			struct btrfs_disk_key disk_key;
821
			orig_slot += left_nr;
822 823 824 825 826
			btrfs_node_key(mid, &disk_key, 0);
			btrfs_set_node_key(parent, &disk_key, pslot);
			btrfs_mark_buffer_dirty(parent);
			if (btrfs_header_nritems(left) > orig_slot) {
				path->nodes[level] = left;
827 828
				path->slots[level + 1] -= 1;
				path->slots[level] = orig_slot;
829
				free_extent_buffer(mid);
830 831
			} else {
				orig_slot -=
832
					btrfs_header_nritems(left);
833
				path->slots[level] = orig_slot;
834
				free_extent_buffer(left);
835 836 837
			}
			return 0;
		}
838
		free_extent_buffer(left);
839
	}
840
	right= read_node_slot(root, parent, pslot + 1);
841 842 843 844

	/*
	 * then try to empty the right most buffer into the middle
	 */
845
	if (right) {
C
Chris Mason 已提交
846
		u32 right_nr;
847
		right_nr = btrfs_header_nritems(right);
C
Chris Mason 已提交
848 849 850
		if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
			wret = 1;
		} else {
851 852 853
			ret = btrfs_cow_block(trans, root, right,
					      parent, pslot + 1,
					      &right);
854 855 856 857
			if (ret)
				wret = 1;
			else {
				wret = balance_node_right(trans, root,
858
							  right, mid);
859
			}
C
Chris Mason 已提交
860
		}
861 862 863
		if (wret < 0)
			ret = wret;
		if (wret == 0) {
864 865 866 867 868 869 870 871
			struct btrfs_disk_key disk_key;

			btrfs_node_key(right, &disk_key, 0);
			btrfs_set_node_key(parent, &disk_key, pslot + 1);
			btrfs_mark_buffer_dirty(parent);

			if (btrfs_header_nritems(mid) <= orig_slot) {
				path->nodes[level] = right;
872 873
				path->slots[level + 1] += 1;
				path->slots[level] = orig_slot -
874 875
					btrfs_header_nritems(mid);
				free_extent_buffer(mid);
876
			} else {
877
				free_extent_buffer(right);
878 879 880
			}
			return 0;
		}
881
		free_extent_buffer(right);
882 883 884 885
	}
	return 1;
}

886 887 888 889
/*
 * readahead one full node of leaves
 */
static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
890
			     int level, int slot)
891
{
892
	struct extent_buffer *node;
893 894
	u32 nritems;
	u64 search;
895 896 897
	u64 lowest_read;
	u64 highest_read;
	u64 nread = 0;
898
	int direction = path->reada;
899
	struct extent_buffer *eb;
900 901 902
	u32 nr;
	u32 blocksize;
	u32 nscan = 0;
903

904 905 906 907
	if (level == 0)
		return;

	if (!path->nodes[level])
908 909
		return;

910
	node = path->nodes[level];
911
	search = btrfs_node_blockptr(node, slot);
912 913
	blocksize = btrfs_level_size(root, level - 1);
	eb = btrfs_find_tree_block(root, search, blocksize);
914 915
	if (eb) {
		free_extent_buffer(eb);
916 917 918
		return;
	}

919 920 921
	highest_read = search;
	lowest_read = search;

922
	nritems = btrfs_header_nritems(node);
923
	nr = slot;
924
	while(1) {
925 926 927 928 929 930 931 932
		if (direction < 0) {
			if (nr == 0)
				break;
			nr--;
		} else if (direction > 0) {
			nr++;
			if (nr >= nritems)
				break;
933
		}
934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950
		search = btrfs_node_blockptr(node, nr);
		if ((search >= lowest_read && search <= highest_read) ||
		    (search < lowest_read && lowest_read - search <= 32768) ||
		    (search > highest_read && search - highest_read <= 32768)) {
			readahead_tree_block(root, search, blocksize);
			nread += blocksize;
		}
		nscan++;
		if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32))
			break;
		if(nread > (1024 * 1024) || nscan > 128)
			break;

		if (search < lowest_read)
			lowest_read = search;
		if (search > highest_read)
			highest_read = search;
951 952
	}
}
C
Chris Mason 已提交
953 954 955 956 957 958
/*
 * look for key in the tree.  path is filled in with nodes along the way
 * if key is found, we return zero and you can find the item in the leaf
 * level of the path (level 0)
 *
 * If the key isn't found, the path points to the slot where it should
C
Chris Mason 已提交
959 960
 * be inserted, and 1 is returned.  If there are other errors during the
 * search a negative error number is returned.
C
Chris Mason 已提交
961 962 963 964
 *
 * if ins_len > 0, nodes and leaves will be split as we walk down the
 * tree.  if ins_len < 0, nodes will be merged as we walk down the tree (if
 * possible)
C
Chris Mason 已提交
965
 */
966 967 968
int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
		      *root, struct btrfs_key *key, struct btrfs_path *p, int
		      ins_len, int cow)
969
{
970
	struct extent_buffer *b;
971
	u64 bytenr;
972 973 974
	int slot;
	int ret;
	int level;
975
	int should_reada = p->reada;
976 977
	u8 lowest_level = 0;

978 979
	lowest_level = p->lowest_level;
	WARN_ON(lowest_level && ins_len);
C
Chris Mason 已提交
980 981
	WARN_ON(p->nodes[0] != NULL);
	WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex));
982 983
again:
	b = root->node;
984
	extent_buffer_get(b);
985
	while (b) {
986
		level = btrfs_header_level(b);
C
Chris Mason 已提交
987 988
		if (cow) {
			int wret;
C
Chris Mason 已提交
989 990 991
			wret = btrfs_cow_block(trans, root, b,
					       p->nodes[level + 1],
					       p->slots[level + 1],
Y
Yan 已提交
992
					       &b);
993
			if (wret) {
994
				free_extent_buffer(b);
995 996
				return wret;
			}
C
Chris Mason 已提交
997 998
		}
		BUG_ON(!cow && ins_len);
999
		if (level != btrfs_header_level(b))
C
Chris Mason 已提交
1000
			WARN_ON(1);
1001
		level = btrfs_header_level(b);
1002
		p->nodes[level] = b;
C
Chris Mason 已提交
1003
		ret = check_block(root, p, level);
C
Chris Mason 已提交
1004 1005
		if (ret)
			return -1;
1006 1007
		ret = bin_search(b, key, level, &slot);
		if (level != 0) {
1008 1009 1010
			if (ret && slot > 0)
				slot -= 1;
			p->slots[level] = slot;
1011
			if (ins_len > 0 && btrfs_header_nritems(b) >=
1012
			    BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
1013
				int sret = split_node(trans, root, p, level);
C
Chris Mason 已提交
1014 1015 1016 1017 1018
				BUG_ON(sret > 0);
				if (sret)
					return sret;
				b = p->nodes[level];
				slot = p->slots[level];
1019
			} else if (ins_len < 0) {
1020 1021
				int sret = balance_level(trans, root, p,
							 level);
1022 1023 1024
				if (sret)
					return sret;
				b = p->nodes[level];
1025 1026
				if (!b) {
					btrfs_release_path(NULL, p);
1027
					goto again;
1028
				}
1029
				slot = p->slots[level];
1030
				BUG_ON(btrfs_header_nritems(b) == 1);
C
Chris Mason 已提交
1031
			}
1032 1033 1034
			/* this is only true while dropping a snapshot */
			if (level == lowest_level)
				break;
1035
			bytenr = btrfs_node_blockptr(b, slot);
1036 1037
			if (should_reada)
				reada_for_search(root, p, level, slot);
1038 1039
			b = read_tree_block(root, bytenr,
					    btrfs_level_size(root, level - 1));
1040 1041
		} else {
			p->slots[level] = slot;
1042
			if (ins_len > 0 && btrfs_leaf_free_space(root, b) <
C
Chris Mason 已提交
1043
			    sizeof(struct btrfs_item) + ins_len) {
1044 1045
				int sret = split_leaf(trans, root, key,
						      p, ins_len);
C
Chris Mason 已提交
1046 1047 1048 1049
				BUG_ON(sret > 0);
				if (sret)
					return sret;
			}
1050 1051 1052
			return ret;
		}
	}
C
Chris Mason 已提交
1053
	return 1;
1054 1055
}

C
Chris Mason 已提交
1056 1057 1058 1059 1060 1061
/*
 * adjust the pointers going up the tree, starting at level
 * making sure the right key of each node is points to 'key'.
 * This is used after shifting pointers to the left, so it stops
 * fixing up pointers when a given leaf/node is not in slot 0 of the
 * higher levels
C
Chris Mason 已提交
1062 1063 1064
 *
 * If this fails to write a tree block, it returns -1, but continues
 * fixing up the blocks in ram so the tree is consistent.
C
Chris Mason 已提交
1065
 */
1066 1067 1068
static int fixup_low_keys(struct btrfs_trans_handle *trans,
			  struct btrfs_root *root, struct btrfs_path *path,
			  struct btrfs_disk_key *key, int level)
1069 1070
{
	int i;
C
Chris Mason 已提交
1071
	int ret = 0;
1072 1073
	struct extent_buffer *t;

C
Chris Mason 已提交
1074
	for (i = level; i < BTRFS_MAX_LEVEL; i++) {
1075
		int tslot = path->slots[i];
1076
		if (!path->nodes[i])
1077
			break;
1078 1079
		t = path->nodes[i];
		btrfs_set_node_key(t, key, tslot);
C
Chris Mason 已提交
1080
		btrfs_mark_buffer_dirty(path->nodes[i]);
1081 1082 1083
		if (tslot != 0)
			break;
	}
C
Chris Mason 已提交
1084
	return ret;
1085 1086
}

C
Chris Mason 已提交
1087 1088
/*
 * try to push data from one node into the next node left in the
1089
 * tree.
C
Chris Mason 已提交
1090 1091 1092
 *
 * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
 * error, and > 0 if there was no room in the left hand block.
C
Chris Mason 已提交
1093
 */
1094
static int push_node_left(struct btrfs_trans_handle *trans, struct btrfs_root
1095 1096
			  *root, struct extent_buffer *dst,
			  struct extent_buffer *src)
1097 1098
{
	int push_items = 0;
1099 1100
	int src_nritems;
	int dst_nritems;
C
Chris Mason 已提交
1101
	int ret = 0;
1102

1103 1104
	src_nritems = btrfs_header_nritems(src);
	dst_nritems = btrfs_header_nritems(dst);
C
Chris Mason 已提交
1105
	push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1106

1107
	if (push_items <= 0) {
1108
		return 1;
1109
	}
1110

1111
	if (src_nritems < push_items)
1112 1113
		push_items = src_nritems;

1114 1115 1116 1117 1118
	copy_extent_buffer(dst, src,
			   btrfs_node_key_ptr_offset(dst_nritems),
			   btrfs_node_key_ptr_offset(0),
		           push_items * sizeof(struct btrfs_key_ptr));

1119
	if (push_items < src_nritems) {
1120 1121 1122 1123 1124 1125 1126 1127 1128
		memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
				      btrfs_node_key_ptr_offset(push_items),
				      (src_nritems - push_items) *
				      sizeof(struct btrfs_key_ptr));
	}
	btrfs_set_header_nritems(src, src_nritems - push_items);
	btrfs_set_header_nritems(dst, dst_nritems + push_items);
	btrfs_mark_buffer_dirty(src);
	btrfs_mark_buffer_dirty(dst);
1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140
	return ret;
}

/*
 * try to push data from one node into the next node right in the
 * tree.
 *
 * returns 0 if some ptrs were pushed, < 0 if there was some horrible
 * error, and > 0 if there was no room in the right hand block.
 *
 * this will  only push up to 1/2 the contents of the left node over
 */
1141 1142 1143 1144
static int balance_node_right(struct btrfs_trans_handle *trans,
			      struct btrfs_root *root,
			      struct extent_buffer *dst,
			      struct extent_buffer *src)
1145 1146 1147 1148 1149 1150 1151
{
	int push_items = 0;
	int max_push;
	int src_nritems;
	int dst_nritems;
	int ret = 0;

1152 1153
	src_nritems = btrfs_header_nritems(src);
	dst_nritems = btrfs_header_nritems(dst);
C
Chris Mason 已提交
1154
	push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
1155
	if (push_items <= 0)
1156 1157 1158 1159
		return 1;

	max_push = src_nritems / 2 + 1;
	/* don't try to empty the node */
Y
Yan 已提交
1160
	if (max_push >= src_nritems)
1161
		return 1;
Y
Yan 已提交
1162

1163 1164 1165
	if (max_push < push_items)
		push_items = max_push;

1166 1167 1168 1169
	memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
				      btrfs_node_key_ptr_offset(0),
				      (dst_nritems) *
				      sizeof(struct btrfs_key_ptr));
C
Chris Mason 已提交
1170

1171 1172 1173 1174
	copy_extent_buffer(dst, src,
			   btrfs_node_key_ptr_offset(0),
			   btrfs_node_key_ptr_offset(src_nritems - push_items),
		           push_items * sizeof(struct btrfs_key_ptr));
1175

1176 1177
	btrfs_set_header_nritems(src, src_nritems - push_items);
	btrfs_set_header_nritems(dst, dst_nritems + push_items);
1178

1179 1180
	btrfs_mark_buffer_dirty(src);
	btrfs_mark_buffer_dirty(dst);
C
Chris Mason 已提交
1181
	return ret;
1182 1183
}

C
Chris Mason 已提交
1184 1185 1186 1187
/*
 * helper function to insert a new root level in the tree.
 * A new node is allocated, and a single item is inserted to
 * point to the existing root
C
Chris Mason 已提交
1188 1189
 *
 * returns zero on success or < 0 on failure.
C
Chris Mason 已提交
1190
 */
1191 1192 1193
static int insert_new_root(struct btrfs_trans_handle *trans,
			   struct btrfs_root *root,
			   struct btrfs_path *path, int level)
C
Chris Mason 已提交
1194
{
1195 1196 1197
	struct extent_buffer *lower;
	struct extent_buffer *c;
	struct btrfs_disk_key lower_key;
C
Chris Mason 已提交
1198 1199 1200 1201

	BUG_ON(path->nodes[level]);
	BUG_ON(path->nodes[level-1] != root->node);

1202 1203
	c = btrfs_alloc_free_block(trans, root, root->nodesize,
				   root->node->start, 0);
1204 1205 1206 1207 1208
	if (IS_ERR(c))
		return PTR_ERR(c);
	memset_extent_buffer(c, 0, 0, root->nodesize);
	btrfs_set_header_nritems(c, 1);
	btrfs_set_header_level(c, level);
1209
	btrfs_set_header_bytenr(c, c->start);
1210 1211 1212 1213 1214 1215 1216 1217 1218
	btrfs_set_header_generation(c, trans->transid);
	btrfs_set_header_owner(c, root->root_key.objectid);
	lower = path->nodes[level-1];

	write_extent_buffer(c, root->fs_info->fsid,
			    (unsigned long)btrfs_header_fsid(c),
			    BTRFS_FSID_SIZE);
	if (level == 1)
		btrfs_item_key(lower, &lower_key, 0);
C
Chris Mason 已提交
1219
	else
1220 1221
		btrfs_node_key(lower, &lower_key, 0);
	btrfs_set_node_key(c, &lower_key, 0);
1222
	btrfs_set_node_blockptr(c, 0, lower->start);
1223

1224
	btrfs_mark_buffer_dirty(c);
1225

C
Chris Mason 已提交
1226
	/* the super has an extra ref to root->node */
1227 1228 1229 1230
	free_extent_buffer(root->node);
	root->node = c;
	extent_buffer_get(c);
	path->nodes[level] = c;
C
Chris Mason 已提交
1231 1232 1233 1234
	path->slots[level] = 0;
	return 0;
}

C
Chris Mason 已提交
1235 1236 1237
/*
 * worker function to insert a single pointer in a node.
 * the node should have enough room for the pointer already
C
Chris Mason 已提交
1238
 *
C
Chris Mason 已提交
1239 1240
 * slot and level indicate where you want the key to go, and
 * blocknr is the block the key points to.
C
Chris Mason 已提交
1241 1242
 *
 * returns zero on success and < 0 on any error
C
Chris Mason 已提交
1243
 */
1244 1245
static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
		      *root, struct btrfs_path *path, struct btrfs_disk_key
1246
		      *key, u64 bytenr, int slot, int level)
C
Chris Mason 已提交
1247
{
1248
	struct extent_buffer *lower;
C
Chris Mason 已提交
1249
	int nritems;
C
Chris Mason 已提交
1250 1251

	BUG_ON(!path->nodes[level]);
1252 1253
	lower = path->nodes[level];
	nritems = btrfs_header_nritems(lower);
C
Chris Mason 已提交
1254 1255
	if (slot > nritems)
		BUG();
C
Chris Mason 已提交
1256
	if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
C
Chris Mason 已提交
1257 1258
		BUG();
	if (slot != nritems) {
1259 1260 1261
		memmove_extent_buffer(lower,
			      btrfs_node_key_ptr_offset(slot + 1),
			      btrfs_node_key_ptr_offset(slot),
C
Chris Mason 已提交
1262
			      (nritems - slot) * sizeof(struct btrfs_key_ptr));
C
Chris Mason 已提交
1263
	}
1264
	btrfs_set_node_key(lower, key, slot);
1265
	btrfs_set_node_blockptr(lower, slot, bytenr);
1266 1267
	btrfs_set_header_nritems(lower, nritems + 1);
	btrfs_mark_buffer_dirty(lower);
C
Chris Mason 已提交
1268 1269 1270
	return 0;
}

C
Chris Mason 已提交
1271 1272 1273 1274 1275 1276
/*
 * split the node at the specified level in path in two.
 * The path is corrected to point to the appropriate node after the split
 *
 * Before splitting this tries to make some room in the node by pushing
 * left and right, if either one works, it returns right away.
C
Chris Mason 已提交
1277 1278
 *
 * returns 0 on success and < 0 on failure
C
Chris Mason 已提交
1279
 */
1280 1281
static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
		      *root, struct btrfs_path *path, int level)
1282
{
1283 1284 1285
	struct extent_buffer *c;
	struct extent_buffer *split;
	struct btrfs_disk_key disk_key;
1286
	int mid;
C
Chris Mason 已提交
1287
	int ret;
C
Chris Mason 已提交
1288
	int wret;
1289
	u32 c_nritems;
1290

1291 1292
	c = path->nodes[level];
	if (c == root->node) {
C
Chris Mason 已提交
1293
		/* trying to split the root, lets make a new one */
1294
		ret = insert_new_root(trans, root, path, level + 1);
C
Chris Mason 已提交
1295 1296
		if (ret)
			return ret;
1297 1298
	} else {
		ret = push_nodes_for_insert(trans, root, path, level);
1299 1300
		c = path->nodes[level];
		if (!ret && btrfs_header_nritems(c) <
1301 1302
		    BTRFS_NODEPTRS_PER_BLOCK(root) - 1)
			return 0;
1303 1304
		if (ret < 0)
			return ret;
1305
	}
1306

1307
	c_nritems = btrfs_header_nritems(c);
1308 1309
	split = btrfs_alloc_free_block(trans, root, root->nodesize,
				       c->start, 0);
1310 1311 1312 1313 1314
	if (IS_ERR(split))
		return PTR_ERR(split);

	btrfs_set_header_flags(split, btrfs_header_flags(c));
	btrfs_set_header_level(split, btrfs_header_level(c));
1315
	btrfs_set_header_bytenr(split, split->start);
1316 1317 1318 1319 1320
	btrfs_set_header_generation(split, trans->transid);
	btrfs_set_header_owner(split, root->root_key.objectid);
	write_extent_buffer(split, root->fs_info->fsid,
			    (unsigned long)btrfs_header_fsid(split),
			    BTRFS_FSID_SIZE);
1321

1322
	mid = (c_nritems + 1) / 2;
1323 1324 1325 1326 1327 1328 1329

	copy_extent_buffer(split, c,
			   btrfs_node_key_ptr_offset(0),
			   btrfs_node_key_ptr_offset(mid),
			   (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
	btrfs_set_header_nritems(split, c_nritems - mid);
	btrfs_set_header_nritems(c, mid);
C
Chris Mason 已提交
1330 1331
	ret = 0;

1332 1333 1334 1335
	btrfs_mark_buffer_dirty(c);
	btrfs_mark_buffer_dirty(split);

	btrfs_node_key(split, &disk_key, 0);
1336
	wret = insert_ptr(trans, root, path, &disk_key, split->start,
1337
			  path->slots[level + 1] + 1,
C
Chris Mason 已提交
1338
			  level + 1);
C
Chris Mason 已提交
1339 1340 1341
	if (wret)
		ret = wret;

C
Chris Mason 已提交
1342
	if (path->slots[level] >= mid) {
C
Chris Mason 已提交
1343
		path->slots[level] -= mid;
1344 1345
		free_extent_buffer(c);
		path->nodes[level] = split;
C
Chris Mason 已提交
1346 1347
		path->slots[level + 1] += 1;
	} else {
1348
		free_extent_buffer(split);
1349
	}
C
Chris Mason 已提交
1350
	return ret;
1351 1352
}

C
Chris Mason 已提交
1353 1354 1355 1356 1357
/*
 * how many bytes are required to store the items in a leaf.  start
 * and nr indicate which items in the leaf to check.  This totals up the
 * space used both by the item structs and the item data
 */
1358
static int leaf_space_used(struct extent_buffer *l, int start, int nr)
1359 1360
{
	int data_len;
1361
	int nritems = btrfs_header_nritems(l);
1362
	int end = min(nritems, start + nr) - 1;
1363 1364 1365

	if (!nr)
		return 0;
1366 1367
	data_len = btrfs_item_end_nr(l, start);
	data_len = data_len - btrfs_item_offset_nr(l, end);
C
Chris Mason 已提交
1368
	data_len += sizeof(struct btrfs_item) * nr;
1369
	WARN_ON(data_len < 0);
1370 1371 1372
	return data_len;
}

1373 1374 1375 1376 1377
/*
 * The space between the end of the leaf items and
 * the start of the leaf data.  IOW, how much room
 * the leaf has left for both items and data
 */
1378
int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
1379
{
1380 1381 1382 1383 1384 1385 1386 1387 1388
	int nritems = btrfs_header_nritems(leaf);
	int ret;
	ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
	if (ret < 0) {
		printk("leaf free space ret %d, leaf data size %lu, used %d nritems %d\n",
		       ret, BTRFS_LEAF_DATA_SIZE(root),
		       leaf_space_used(leaf, 0, nritems), nritems);
	}
	return ret;
1389 1390
}

C
Chris Mason 已提交
1391 1392 1393
/*
 * push some data in the path leaf to the right, trying to free up at
 * least data_size bytes.  returns zero if the push worked, nonzero otherwise
C
Chris Mason 已提交
1394 1395 1396
 *
 * returns 1 if the push failed because the other node didn't have enough
 * room, 0 if everything worked out and < 0 if there were major errors.
C
Chris Mason 已提交
1397
 */
1398 1399
static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
			   *root, struct btrfs_path *path, int data_size)
C
Chris Mason 已提交
1400
{
1401 1402 1403 1404
	struct extent_buffer *left = path->nodes[0];
	struct extent_buffer *right;
	struct extent_buffer *upper;
	struct btrfs_disk_key disk_key;
C
Chris Mason 已提交
1405 1406 1407 1408 1409
	int slot;
	int i;
	int free_space;
	int push_space = 0;
	int push_items = 0;
C
Chris Mason 已提交
1410
	struct btrfs_item *item;
1411 1412
	u32 left_nritems;
	u32 right_nritems;
1413
	u32 data_end;
1414
	u32 this_item_size;
1415
	int ret;
C
Chris Mason 已提交
1416 1417 1418 1419 1420 1421

	slot = path->slots[1];
	if (!path->nodes[1]) {
		return 1;
	}
	upper = path->nodes[1];
1422
	if (slot >= btrfs_header_nritems(upper) - 1)
C
Chris Mason 已提交
1423
		return 1;
1424

1425 1426
	right = read_tree_block(root, btrfs_node_blockptr(upper, slot + 1),
				root->leafsize);
C
Chris Mason 已提交
1427
	free_space = btrfs_leaf_free_space(root, right);
C
Chris Mason 已提交
1428
	if (free_space < data_size + sizeof(struct btrfs_item)) {
1429
		free_extent_buffer(right);
C
Chris Mason 已提交
1430 1431
		return 1;
	}
1432

C
Chris Mason 已提交
1433
	/* cow and double check */
1434 1435
	ret = btrfs_cow_block(trans, root, right, upper,
			      slot + 1, &right);
1436
	if (ret) {
1437
		free_extent_buffer(right);
1438 1439
		return 1;
	}
C
Chris Mason 已提交
1440
	free_space = btrfs_leaf_free_space(root, right);
C
Chris Mason 已提交
1441
	if (free_space < data_size + sizeof(struct btrfs_item)) {
1442
		free_extent_buffer(right);
C
Chris Mason 已提交
1443 1444 1445
		return 1;
	}

1446
	left_nritems = btrfs_header_nritems(left);
1447
	if (left_nritems == 0) {
1448
		free_extent_buffer(right);
1449 1450
		return 1;
	}
1451

1452
	for (i = left_nritems - 1; i >= 1; i--) {
1453
		item = btrfs_item_nr(left, i);
1454

C
Chris Mason 已提交
1455 1456
		if (path->slots[0] == i)
			push_space += data_size + sizeof(*item);
1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467

		if (!left->map_token) {
			map_extent_buffer(left, (unsigned long)item,
					sizeof(struct btrfs_item),
					&left->map_token, &left->kaddr,
					&left->map_start, &left->map_len,
					KM_USER1);
		}

		this_item_size = btrfs_item_size(left, item);
		if (this_item_size + sizeof(*item) + push_space > free_space)
C
Chris Mason 已提交
1468 1469
			break;
		push_items++;
1470 1471 1472 1473 1474
		push_space += this_item_size + sizeof(*item);
	}
	if (left->map_token) {
		unmap_extent_buffer(left, left->map_token, KM_USER1);
		left->map_token = NULL;
C
Chris Mason 已提交
1475
	}
1476

C
Chris Mason 已提交
1477
	if (push_items == 0) {
1478
		free_extent_buffer(right);
C
Chris Mason 已提交
1479 1480
		return 1;
	}
1481

1482 1483
	if (push_items == left_nritems)
		WARN_ON(1);
1484

C
Chris Mason 已提交
1485
	/* push left to right */
1486 1487
	right_nritems = btrfs_header_nritems(right);
	push_space = btrfs_item_end_nr(left, left_nritems - push_items);
C
Chris Mason 已提交
1488
	push_space -= leaf_data_end(root, left);
1489

C
Chris Mason 已提交
1490
	/* make room in the right data area */
1491 1492 1493 1494 1495 1496
	data_end = leaf_data_end(root, right);
	memmove_extent_buffer(right,
			      btrfs_leaf_data(right) + data_end - push_space,
			      btrfs_leaf_data(right) + data_end,
			      BTRFS_LEAF_DATA_SIZE(root) - data_end);

C
Chris Mason 已提交
1497
	/* copy from the left data area */
1498
	copy_extent_buffer(right, left, btrfs_leaf_data(right) +
C
Chris Mason 已提交
1499 1500 1501
		     BTRFS_LEAF_DATA_SIZE(root) - push_space,
		     btrfs_leaf_data(left) + leaf_data_end(root, left),
		     push_space);
1502 1503 1504 1505 1506

	memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
			      btrfs_item_nr_offset(0),
			      right_nritems * sizeof(struct btrfs_item));

C
Chris Mason 已提交
1507
	/* copy the items from left to right */
1508 1509 1510
	copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
		   btrfs_item_nr_offset(left_nritems - push_items),
		   push_items * sizeof(struct btrfs_item));
C
Chris Mason 已提交
1511 1512

	/* update the item pointers */
1513
	right_nritems += push_items;
1514
	btrfs_set_header_nritems(right, right_nritems);
C
Chris Mason 已提交
1515
	push_space = BTRFS_LEAF_DATA_SIZE(root);
1516

1517
	for (i = 0; i < right_nritems; i++) {
1518
		item = btrfs_item_nr(right, i);
1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532
		if (!right->map_token) {
			map_extent_buffer(right, (unsigned long)item,
					sizeof(struct btrfs_item),
					&right->map_token, &right->kaddr,
					&right->map_start, &right->map_len,
					KM_USER1);
		}
		push_space -= btrfs_item_size(right, item);
		btrfs_set_item_offset(right, item, push_space);
	}

	if (right->map_token) {
		unmap_extent_buffer(right, right->map_token, KM_USER1);
		right->map_token = NULL;
C
Chris Mason 已提交
1533
	}
1534
	left_nritems -= push_items;
1535
	btrfs_set_header_nritems(left, left_nritems);
C
Chris Mason 已提交
1536

1537 1538
	btrfs_mark_buffer_dirty(left);
	btrfs_mark_buffer_dirty(right);
1539

1540 1541
	btrfs_item_key(right, &disk_key, 0);
	btrfs_set_node_key(upper, &disk_key, slot + 1);
C
Chris Mason 已提交
1542
	btrfs_mark_buffer_dirty(upper);
C
Chris Mason 已提交
1543

C
Chris Mason 已提交
1544
	/* then fixup the leaf pointer in the path */
1545 1546
	if (path->slots[0] >= left_nritems) {
		path->slots[0] -= left_nritems;
1547 1548
		free_extent_buffer(path->nodes[0]);
		path->nodes[0] = right;
C
Chris Mason 已提交
1549 1550
		path->slots[1] += 1;
	} else {
1551
		free_extent_buffer(right);
C
Chris Mason 已提交
1552 1553 1554
	}
	return 0;
}
C
Chris Mason 已提交
1555 1556 1557 1558
/*
 * push some data in the path leaf to the left, trying to free up at
 * least data_size bytes.  returns zero if the push worked, nonzero otherwise
 */
1559 1560
static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
			  *root, struct btrfs_path *path, int data_size)
1561
{
1562 1563 1564
	struct btrfs_disk_key disk_key;
	struct extent_buffer *right = path->nodes[0];
	struct extent_buffer *left;
1565 1566 1567 1568 1569
	int slot;
	int i;
	int free_space;
	int push_space = 0;
	int push_items = 0;
C
Chris Mason 已提交
1570
	struct btrfs_item *item;
1571
	u32 old_left_nritems;
1572
	u32 right_nritems;
C
Chris Mason 已提交
1573 1574
	int ret = 0;
	int wret;
1575 1576
	u32 this_item_size;
	u32 old_left_item_size;
1577 1578

	slot = path->slots[1];
1579
	if (slot == 0)
1580
		return 1;
1581
	if (!path->nodes[1])
1582
		return 1;
1583 1584

	left = read_tree_block(root, btrfs_node_blockptr(path->nodes[1],
1585
			       slot - 1), root->leafsize);
C
Chris Mason 已提交
1586
	free_space = btrfs_leaf_free_space(root, left);
C
Chris Mason 已提交
1587
	if (free_space < data_size + sizeof(struct btrfs_item)) {
1588
		free_extent_buffer(left);
1589 1590
		return 1;
	}
C
Chris Mason 已提交
1591 1592

	/* cow and double check */
1593 1594
	ret = btrfs_cow_block(trans, root, left,
			      path->nodes[1], slot - 1, &left);
1595 1596
	if (ret) {
		/* we hit -ENOSPC, but it isn't fatal here */
1597
		free_extent_buffer(left);
1598 1599
		return 1;
	}
C
Chris Mason 已提交
1600
	free_space = btrfs_leaf_free_space(root, left);
C
Chris Mason 已提交
1601
	if (free_space < data_size + sizeof(struct btrfs_item)) {
1602
		free_extent_buffer(left);
C
Chris Mason 已提交
1603 1604 1605
		return 1;
	}

1606 1607 1608
	right_nritems = btrfs_header_nritems(right);
	if (right_nritems == 0) {
		free_extent_buffer(left);
1609 1610 1611
		return 1;
	}

1612 1613
	for (i = 0; i < right_nritems - 1; i++) {
		item = btrfs_item_nr(right, i);
1614 1615 1616 1617 1618 1619 1620 1621
		if (!right->map_token) {
			map_extent_buffer(right, (unsigned long)item,
					sizeof(struct btrfs_item),
					&right->map_token, &right->kaddr,
					&right->map_start, &right->map_len,
					KM_USER1);
		}

1622 1623
		if (path->slots[0] == i)
			push_space += data_size + sizeof(*item);
1624 1625 1626

		this_item_size = btrfs_item_size(right, item);
		if (this_item_size + sizeof(*item) + push_space > free_space)
1627
			break;
1628

1629
		push_items++;
1630 1631 1632 1633 1634 1635
		push_space += this_item_size + sizeof(*item);
	}

	if (right->map_token) {
		unmap_extent_buffer(right, right->map_token, KM_USER1);
		right->map_token = NULL;
1636
	}
1637

1638
	if (push_items == 0) {
1639
		free_extent_buffer(left);
1640 1641
		return 1;
	}
1642
	if (push_items == btrfs_header_nritems(right))
1643
		WARN_ON(1);
1644

1645
	/* push data from right to left */
1646 1647 1648 1649 1650
	copy_extent_buffer(left, right,
			   btrfs_item_nr_offset(btrfs_header_nritems(left)),
			   btrfs_item_nr_offset(0),
			   push_items * sizeof(struct btrfs_item));

C
Chris Mason 已提交
1651
	push_space = BTRFS_LEAF_DATA_SIZE(root) -
1652 1653 1654
		     btrfs_item_offset_nr(right, push_items -1);

	copy_extent_buffer(left, right, btrfs_leaf_data(left) +
C
Chris Mason 已提交
1655 1656
		     leaf_data_end(root, left) - push_space,
		     btrfs_leaf_data(right) +
1657
		     btrfs_item_offset_nr(right, push_items - 1),
C
Chris Mason 已提交
1658
		     push_space);
1659
	old_left_nritems = btrfs_header_nritems(left);
1660 1661
	BUG_ON(old_left_nritems < 0);

1662
	old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
C
Chris Mason 已提交
1663
	for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
1664
		u32 ioff;
1665

1666
		item = btrfs_item_nr(left, i);
1667 1668 1669 1670 1671 1672 1673 1674
		if (!left->map_token) {
			map_extent_buffer(left, (unsigned long)item,
					sizeof(struct btrfs_item),
					&left->map_token, &left->kaddr,
					&left->map_start, &left->map_len,
					KM_USER1);
		}

1675 1676
		ioff = btrfs_item_offset(left, item);
		btrfs_set_item_offset(left, item,
1677
		      ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size));
1678
	}
1679
	btrfs_set_header_nritems(left, old_left_nritems + push_items);
1680 1681 1682 1683
	if (left->map_token) {
		unmap_extent_buffer(left, left->map_token, KM_USER1);
		left->map_token = NULL;
	}
1684 1685

	/* fixup right node */
1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699
	push_space = btrfs_item_offset_nr(right, push_items - 1) -
					  leaf_data_end(root, right);
	memmove_extent_buffer(right, btrfs_leaf_data(right) +
			      BTRFS_LEAF_DATA_SIZE(root) - push_space,
			      btrfs_leaf_data(right) +
			      leaf_data_end(root, right), push_space);

	memmove_extent_buffer(right, btrfs_item_nr_offset(0),
			      btrfs_item_nr_offset(push_items),
			     (btrfs_header_nritems(right) - push_items) *
			     sizeof(struct btrfs_item));

	right_nritems = btrfs_header_nritems(right) - push_items;
	btrfs_set_header_nritems(right, right_nritems);
C
Chris Mason 已提交
1700
	push_space = BTRFS_LEAF_DATA_SIZE(root);
1701

1702 1703
	for (i = 0; i < right_nritems; i++) {
		item = btrfs_item_nr(right, i);
1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718

		if (!right->map_token) {
			map_extent_buffer(right, (unsigned long)item,
					sizeof(struct btrfs_item),
					&right->map_token, &right->kaddr,
					&right->map_start, &right->map_len,
					KM_USER1);
		}

		push_space = push_space - btrfs_item_size(right, item);
		btrfs_set_item_offset(right, item, push_space);
	}
	if (right->map_token) {
		unmap_extent_buffer(right, right->map_token, KM_USER1);
		right->map_token = NULL;
1719
	}
1720

1721 1722
	btrfs_mark_buffer_dirty(left);
	btrfs_mark_buffer_dirty(right);
1723

1724 1725
	btrfs_item_key(right, &disk_key, 0);
	wret = fixup_low_keys(trans, root, path, &disk_key, 1);
C
Chris Mason 已提交
1726 1727
	if (wret)
		ret = wret;
1728 1729 1730 1731

	/* then fixup the leaf pointer in the path */
	if (path->slots[0] < push_items) {
		path->slots[0] += old_left_nritems;
1732 1733
		free_extent_buffer(path->nodes[0]);
		path->nodes[0] = left;
1734 1735
		path->slots[1] -= 1;
	} else {
1736
		free_extent_buffer(left);
1737 1738
		path->slots[0] -= push_items;
	}
1739
	BUG_ON(path->slots[0] < 0);
C
Chris Mason 已提交
1740
	return ret;
1741 1742
}

C
Chris Mason 已提交
1743 1744 1745
/*
 * split the path's leaf in two, making sure there is at least data_size
 * available for the resulting leaf level of the path.
C
Chris Mason 已提交
1746 1747
 *
 * returns 0 if all went well and < 0 on failure.
C
Chris Mason 已提交
1748
 */
1749
static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
1750 1751
		      *root, struct btrfs_key *ins_key,
		      struct btrfs_path *path, int data_size)
1752
{
1753
	struct extent_buffer *l;
1754
	u32 nritems;
1755 1756
	int mid;
	int slot;
1757
	struct extent_buffer *right;
C
Chris Mason 已提交
1758
	int space_needed = data_size + sizeof(struct btrfs_item);
1759 1760 1761
	int data_copy_size;
	int rt_data_off;
	int i;
1762
	int ret = 0;
C
Chris Mason 已提交
1763
	int wret;
1764 1765
	int double_split = 0;
	struct btrfs_disk_key disk_key;
C
Chris Mason 已提交
1766

C
Chris Mason 已提交
1767
	/* first try to make some room by pushing left and right */
1768
	wret = push_leaf_left(trans, root, path, data_size);
1769
	if (wret < 0) {
C
Chris Mason 已提交
1770
		return wret;
1771
	}
C
Chris Mason 已提交
1772
	if (wret) {
1773
		wret = push_leaf_right(trans, root, path, data_size);
C
Chris Mason 已提交
1774 1775 1776
		if (wret < 0)
			return wret;
	}
1777
	l = path->nodes[0];
C
Chris Mason 已提交
1778 1779

	/* did the pushes work? */
C
Chris Mason 已提交
1780
	if (btrfs_leaf_free_space(root, l) >=
1781
	    sizeof(struct btrfs_item) + data_size) {
C
Chris Mason 已提交
1782
		return 0;
1783
	}
C
Chris Mason 已提交
1784

C
Chris Mason 已提交
1785
	if (!path->nodes[1]) {
1786
		ret = insert_new_root(trans, root, path, 1);
C
Chris Mason 已提交
1787 1788 1789
		if (ret)
			return ret;
	}
1790
	slot = path->slots[0];
1791
	nritems = btrfs_header_nritems(l);
1792
	mid = (nritems + 1)/ 2;
1793

1794 1795
	right = btrfs_alloc_free_block(trans, root, root->leafsize,
				       l->start, 0);
1796 1797 1798 1799
	if (IS_ERR(right))
		return PTR_ERR(right);

	memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
1800
	btrfs_set_header_bytenr(right, right->start);
1801 1802 1803 1804 1805 1806 1807
	btrfs_set_header_generation(right, trans->transid);
	btrfs_set_header_owner(right, root->root_key.objectid);
	btrfs_set_header_level(right, 0);
	write_extent_buffer(right, root->fs_info->fsid,
			    (unsigned long)btrfs_header_fsid(right),
			    BTRFS_FSID_SIZE);

1808 1809 1810 1811 1812 1813
	if (mid <= slot) {
		if (nritems == 1 ||
		    leaf_space_used(l, mid, nritems - mid) + space_needed >
			BTRFS_LEAF_DATA_SIZE(root)) {
			if (slot >= nritems) {
				btrfs_cpu_key_to_disk(&disk_key, ins_key);
1814
				btrfs_set_header_nritems(right, 0);
1815
				wret = insert_ptr(trans, root, path,
1816
						  &disk_key, right->start,
1817 1818 1819
						  path->slots[1] + 1, 1);
				if (wret)
					ret = wret;
1820 1821
				free_extent_buffer(path->nodes[0]);
				path->nodes[0] = right;
1822 1823 1824 1825 1826
				path->slots[0] = 0;
				path->slots[1] += 1;
				return ret;
			}
			mid = slot;
1827 1828 1829 1830 1831
			if (mid != nritems &&
			    leaf_space_used(l, mid, nritems - mid) +
			    space_needed > BTRFS_LEAF_DATA_SIZE(root)) {
				double_split = 1;
			}
1832 1833 1834 1835 1836 1837
		}
	} else {
		if (leaf_space_used(l, 0, mid + 1) + space_needed >
			BTRFS_LEAF_DATA_SIZE(root)) {
			if (slot == 0) {
				btrfs_cpu_key_to_disk(&disk_key, ins_key);
1838
				btrfs_set_header_nritems(right, 0);
1839 1840
				wret = insert_ptr(trans, root, path,
						  &disk_key,
1841
						  right->start,
1842
						  path->slots[1], 1);
1843 1844
				if (wret)
					ret = wret;
1845 1846
				free_extent_buffer(path->nodes[0]);
				path->nodes[0] = right;
1847
				path->slots[0] = 0;
1848 1849 1850 1851 1852 1853
				if (path->slots[1] == 0) {
					wret = fixup_low_keys(trans, root,
					           path, &disk_key, 1);
					if (wret)
						ret = wret;
				}
1854 1855 1856 1857 1858 1859
				return ret;
			}
			mid = slot;
			double_split = 1;
		}
	}
1860 1861 1862 1863 1864 1865 1866 1867 1868
	nritems = nritems - mid;
	btrfs_set_header_nritems(right, nritems);
	data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);

	copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
			   btrfs_item_nr_offset(mid),
			   nritems * sizeof(struct btrfs_item));

	copy_extent_buffer(right, l,
C
Chris Mason 已提交
1869 1870 1871
		     btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
		     data_copy_size, btrfs_leaf_data(l) +
		     leaf_data_end(root, l), data_copy_size);
1872

C
Chris Mason 已提交
1873
	rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
1874
		      btrfs_item_end_nr(l, mid);
C
Chris Mason 已提交
1875

1876 1877
	for (i = 0; i < nritems; i++) {
		struct btrfs_item *item = btrfs_item_nr(right, i);
1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888
		u32 ioff;

		if (!right->map_token) {
			map_extent_buffer(right, (unsigned long)item,
					sizeof(struct btrfs_item),
					&right->map_token, &right->kaddr,
					&right->map_start, &right->map_len,
					KM_USER1);
		}

		ioff = btrfs_item_offset(right, item);
1889
		btrfs_set_item_offset(right, item, ioff + rt_data_off);
C
Chris Mason 已提交
1890
	}
C
Chris Mason 已提交
1891

1892 1893 1894 1895 1896
	if (right->map_token) {
		unmap_extent_buffer(right, right->map_token, KM_USER1);
		right->map_token = NULL;
	}

1897
	btrfs_set_header_nritems(l, mid);
C
Chris Mason 已提交
1898
	ret = 0;
1899
	btrfs_item_key(right, &disk_key, 0);
1900 1901
	wret = insert_ptr(trans, root, path, &disk_key, right->start,
			  path->slots[1] + 1, 1);
C
Chris Mason 已提交
1902 1903
	if (wret)
		ret = wret;
1904 1905 1906

	btrfs_mark_buffer_dirty(right);
	btrfs_mark_buffer_dirty(l);
1907
	BUG_ON(path->slots[0] != slot);
1908

1909
	if (mid <= slot) {
1910 1911
		free_extent_buffer(path->nodes[0]);
		path->nodes[0] = right;
1912 1913
		path->slots[0] -= mid;
		path->slots[1] += 1;
1914
	} else
1915 1916
		free_extent_buffer(right);

1917
	BUG_ON(path->slots[0] < 0);
1918

1919
	if (!double_split) {
1920
		return ret;
1921
	}
1922

1923 1924
	right = btrfs_alloc_free_block(trans, root, root->leafsize,
				       l->start, 0);
1925 1926 1927 1928
	if (IS_ERR(right))
		return PTR_ERR(right);

	memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
1929
	btrfs_set_header_bytenr(right, right->start);
1930 1931 1932 1933 1934 1935 1936
	btrfs_set_header_generation(right, trans->transid);
	btrfs_set_header_owner(right, root->root_key.objectid);
	btrfs_set_header_level(right, 0);
	write_extent_buffer(right, root->fs_info->fsid,
			    (unsigned long)btrfs_header_fsid(right),
			    BTRFS_FSID_SIZE);

1937
	btrfs_cpu_key_to_disk(&disk_key, ins_key);
1938
	btrfs_set_header_nritems(right, 0);
1939
	wret = insert_ptr(trans, root, path,
1940
			  &disk_key, right->start,
1941 1942 1943
			  path->slots[1], 1);
	if (wret)
		ret = wret;
1944 1945 1946 1947 1948
	if (path->slots[1] == 0) {
		wret = fixup_low_keys(trans, root, path, &disk_key, 1);
		if (wret)
			ret = wret;
	}
1949 1950
	free_extent_buffer(path->nodes[0]);
	path->nodes[0] = right;
1951
	path->slots[0] = 0;
1952 1953 1954
	return ret;
}

C
Chris Mason 已提交
1955 1956 1957 1958 1959 1960 1961 1962
int btrfs_truncate_item(struct btrfs_trans_handle *trans,
			struct btrfs_root *root,
			struct btrfs_path *path,
			u32 new_size)
{
	int ret = 0;
	int slot;
	int slot_orig;
1963 1964
	struct extent_buffer *leaf;
	struct btrfs_item *item;
C
Chris Mason 已提交
1965 1966 1967 1968 1969 1970 1971 1972
	u32 nritems;
	unsigned int data_end;
	unsigned int old_data_start;
	unsigned int old_size;
	unsigned int size_diff;
	int i;

	slot_orig = path->slots[0];
1973
	leaf = path->nodes[0];
C
Chris Mason 已提交
1974

1975
	nritems = btrfs_header_nritems(leaf);
C
Chris Mason 已提交
1976 1977 1978
	data_end = leaf_data_end(root, leaf);

	slot = path->slots[0];
1979 1980
	old_data_start = btrfs_item_offset_nr(leaf, slot);
	old_size = btrfs_item_size_nr(leaf, slot);
C
Chris Mason 已提交
1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991
	BUG_ON(old_size <= new_size);
	size_diff = old_size - new_size;

	BUG_ON(slot < 0);
	BUG_ON(slot >= nritems);

	/*
	 * item0..itemN ... dataN.offset..dataN.size .. data0.size
	 */
	/* first correct the data pointers */
	for (i = slot; i < nritems; i++) {
1992 1993
		u32 ioff;
		item = btrfs_item_nr(leaf, i);
1994 1995 1996 1997 1998 1999 2000 2001 2002

		if (!leaf->map_token) {
			map_extent_buffer(leaf, (unsigned long)item,
					sizeof(struct btrfs_item),
					&leaf->map_token, &leaf->kaddr,
					&leaf->map_start, &leaf->map_len,
					KM_USER1);
		}

2003 2004
		ioff = btrfs_item_offset(leaf, item);
		btrfs_set_item_offset(leaf, item, ioff + size_diff);
C
Chris Mason 已提交
2005
	}
2006 2007 2008 2009 2010 2011

	if (leaf->map_token) {
		unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
		leaf->map_token = NULL;
	}

C
Chris Mason 已提交
2012
	/* shift the data */
2013
	memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
C
Chris Mason 已提交
2014 2015
		      data_end + size_diff, btrfs_leaf_data(leaf) +
		      data_end, old_data_start + new_size - data_end);
2016 2017 2018 2019

	item = btrfs_item_nr(leaf, slot);
	btrfs_set_item_size(leaf, item, new_size);
	btrfs_mark_buffer_dirty(leaf);
C
Chris Mason 已提交
2020 2021

	ret = 0;
2022 2023
	if (btrfs_leaf_free_space(root, leaf) < 0) {
		btrfs_print_leaf(root, leaf);
C
Chris Mason 已提交
2024
		BUG();
2025
	}
C
Chris Mason 已提交
2026 2027 2028
	return ret;
}

2029 2030 2031
int btrfs_extend_item(struct btrfs_trans_handle *trans,
		      struct btrfs_root *root, struct btrfs_path *path,
		      u32 data_size)
2032 2033 2034 2035
{
	int ret = 0;
	int slot;
	int slot_orig;
2036 2037
	struct extent_buffer *leaf;
	struct btrfs_item *item;
2038 2039 2040 2041 2042 2043 2044
	u32 nritems;
	unsigned int data_end;
	unsigned int old_data;
	unsigned int old_size;
	int i;

	slot_orig = path->slots[0];
2045
	leaf = path->nodes[0];
2046

2047
	nritems = btrfs_header_nritems(leaf);
2048 2049
	data_end = leaf_data_end(root, leaf);

2050 2051
	if (btrfs_leaf_free_space(root, leaf) < data_size) {
		btrfs_print_leaf(root, leaf);
2052
		BUG();
2053
	}
2054
	slot = path->slots[0];
2055
	old_data = btrfs_item_end_nr(leaf, slot);
2056 2057

	BUG_ON(slot < 0);
2058 2059 2060 2061 2062
	if (slot >= nritems) {
		btrfs_print_leaf(root, leaf);
		printk("slot %d too large, nritems %d\n", slot, nritems);
		BUG_ON(1);
	}
2063 2064 2065 2066 2067 2068

	/*
	 * item0..itemN ... dataN.offset..dataN.size .. data0.size
	 */
	/* first correct the data pointers */
	for (i = slot; i < nritems; i++) {
2069 2070
		u32 ioff;
		item = btrfs_item_nr(leaf, i);
2071 2072 2073 2074 2075 2076 2077 2078

		if (!leaf->map_token) {
			map_extent_buffer(leaf, (unsigned long)item,
					sizeof(struct btrfs_item),
					&leaf->map_token, &leaf->kaddr,
					&leaf->map_start, &leaf->map_len,
					KM_USER1);
		}
2079 2080
		ioff = btrfs_item_offset(leaf, item);
		btrfs_set_item_offset(leaf, item, ioff - data_size);
2081
	}
2082

2083 2084 2085 2086 2087
	if (leaf->map_token) {
		unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
		leaf->map_token = NULL;
	}

2088
	/* shift the data */
2089
	memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
2090 2091
		      data_end - data_size, btrfs_leaf_data(leaf) +
		      data_end, old_data - data_end);
2092

2093
	data_end = old_data;
2094 2095 2096 2097
	old_size = btrfs_item_size_nr(leaf, slot);
	item = btrfs_item_nr(leaf, slot);
	btrfs_set_item_size(leaf, item, old_size + data_size);
	btrfs_mark_buffer_dirty(leaf);
2098 2099

	ret = 0;
2100 2101
	if (btrfs_leaf_free_space(root, leaf) < 0) {
		btrfs_print_leaf(root, leaf);
2102
		BUG();
2103
	}
2104 2105 2106
	return ret;
}

C
Chris Mason 已提交
2107 2108 2109 2110
/*
 * Given a key and some data, insert an item into the tree.
 * This does all the path init required, making room in the tree if needed.
 */
2111 2112 2113 2114
int btrfs_insert_empty_item(struct btrfs_trans_handle *trans,
			    struct btrfs_root *root,
			    struct btrfs_path *path,
			    struct btrfs_key *cpu_key, u32 data_size)
2115
{
2116 2117
	struct extent_buffer *leaf;
	struct btrfs_item *item;
C
Chris Mason 已提交
2118
	int ret = 0;
2119
	int slot;
2120
	int slot_orig;
2121
	u32 nritems;
2122
	unsigned int data_end;
C
Chris Mason 已提交
2123 2124 2125
	struct btrfs_disk_key disk_key;

	btrfs_cpu_key_to_disk(&disk_key, cpu_key);
2126

C
Chris Mason 已提交
2127
	/* create a root if there isn't one */
C
Chris Mason 已提交
2128
	if (!root->node)
C
Chris Mason 已提交
2129
		BUG();
2130

2131
	ret = btrfs_search_slot(trans, root, cpu_key, path, data_size, 1);
2132
	if (ret == 0) {
2133
		return -EEXIST;
C
Chris Mason 已提交
2134
	}
2135 2136
	if (ret < 0)
		goto out;
2137

2138
	slot_orig = path->slots[0];
2139
	leaf = path->nodes[0];
C
Chris Mason 已提交
2140

2141
	nritems = btrfs_header_nritems(leaf);
C
Chris Mason 已提交
2142
	data_end = leaf_data_end(root, leaf);
2143

C
Chris Mason 已提交
2144
	if (btrfs_leaf_free_space(root, leaf) <
2145
	    sizeof(struct btrfs_item) + data_size) {
2146 2147 2148
		btrfs_print_leaf(root, leaf);
		printk("not enough freespace need %u have %d\n",
		       data_size, btrfs_leaf_free_space(root, leaf));
2149
		BUG();
2150
	}
2151

2152
	slot = path->slots[0];
2153
	BUG_ON(slot < 0);
2154

2155 2156
	if (slot != nritems) {
		int i;
2157
		unsigned int old_data = btrfs_item_end_nr(leaf, slot);
2158

2159 2160 2161 2162 2163 2164
		if (old_data < data_end) {
			btrfs_print_leaf(root, leaf);
			printk("slot %d old_data %d data_end %d\n",
			       slot, old_data, data_end);
			BUG_ON(1);
		}
2165 2166 2167 2168
		/*
		 * item0..itemN ... dataN.offset..dataN.size .. data0.size
		 */
		/* first correct the data pointers */
2169
		WARN_ON(leaf->map_token);
C
Chris Mason 已提交
2170
		for (i = slot; i < nritems; i++) {
2171
			u32 ioff;
2172

2173
			item = btrfs_item_nr(leaf, i);
2174 2175 2176 2177 2178 2179 2180 2181
			if (!leaf->map_token) {
				map_extent_buffer(leaf, (unsigned long)item,
					sizeof(struct btrfs_item),
					&leaf->map_token, &leaf->kaddr,
					&leaf->map_start, &leaf->map_len,
					KM_USER1);
			}

2182 2183
			ioff = btrfs_item_offset(leaf, item);
			btrfs_set_item_offset(leaf, item, ioff - data_size);
C
Chris Mason 已提交
2184
		}
2185 2186 2187 2188
		if (leaf->map_token) {
			unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
			leaf->map_token = NULL;
		}
2189 2190

		/* shift the items */
2191 2192
		memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1),
			      btrfs_item_nr_offset(slot),
C
Chris Mason 已提交
2193
			      (nritems - slot) * sizeof(struct btrfs_item));
2194 2195

		/* shift the data */
2196
		memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
C
Chris Mason 已提交
2197 2198
			      data_end - data_size, btrfs_leaf_data(leaf) +
			      data_end, old_data - data_end);
2199 2200
		data_end = old_data;
	}
2201

2202
	/* setup the item for the new data */
2203 2204 2205 2206 2207 2208
	btrfs_set_item_key(leaf, &disk_key, slot);
	item = btrfs_item_nr(leaf, slot);
	btrfs_set_item_offset(leaf, item, data_end - data_size);
	btrfs_set_item_size(leaf, item, data_size);
	btrfs_set_header_nritems(leaf, nritems + 1);
	btrfs_mark_buffer_dirty(leaf);
C
Chris Mason 已提交
2209 2210

	ret = 0;
2211
	if (slot == 0)
2212
		ret = fixup_low_keys(trans, root, path, &disk_key, 1);
C
Chris Mason 已提交
2213

2214 2215
	if (btrfs_leaf_free_space(root, leaf) < 0) {
		btrfs_print_leaf(root, leaf);
2216
		BUG();
2217
	}
2218
out:
2219 2220 2221 2222 2223 2224 2225
	return ret;
}

/*
 * Given a key and some data, insert an item into the tree.
 * This does all the path init required, making room in the tree if needed.
 */
2226 2227 2228
int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
		      *root, struct btrfs_key *cpu_key, void *data, u32
		      data_size)
2229 2230
{
	int ret = 0;
C
Chris Mason 已提交
2231
	struct btrfs_path *path;
2232 2233
	struct extent_buffer *leaf;
	unsigned long ptr;
2234

C
Chris Mason 已提交
2235 2236 2237
	path = btrfs_alloc_path();
	BUG_ON(!path);
	ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
2238
	if (!ret) {
2239 2240 2241 2242
		leaf = path->nodes[0];
		ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
		write_extent_buffer(leaf, data, ptr, data_size);
		btrfs_mark_buffer_dirty(leaf);
2243
	}
C
Chris Mason 已提交
2244
	btrfs_free_path(path);
C
Chris Mason 已提交
2245
	return ret;
2246 2247
}

C
Chris Mason 已提交
2248
/*
C
Chris Mason 已提交
2249
 * delete the pointer from a given node.
C
Chris Mason 已提交
2250 2251 2252 2253 2254
 *
 * If the delete empties a node, the node is removed from the tree,
 * continuing all the way the root if required.  The root is converted into
 * a leaf if all the nodes are emptied.
 */
2255 2256
static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
		   struct btrfs_path *path, int level, int slot)
2257
{
2258
	struct extent_buffer *parent = path->nodes[level];
2259
	u32 nritems;
C
Chris Mason 已提交
2260
	int ret = 0;
2261
	int wret;
2262

2263
	nritems = btrfs_header_nritems(parent);
2264
	if (slot != nritems -1) {
2265 2266 2267
		memmove_extent_buffer(parent,
			      btrfs_node_key_ptr_offset(slot),
			      btrfs_node_key_ptr_offset(slot + 1),
C
Chris Mason 已提交
2268 2269
			      sizeof(struct btrfs_key_ptr) *
			      (nritems - slot - 1));
2270
	}
2271
	nritems--;
2272
	btrfs_set_header_nritems(parent, nritems);
2273
	if (nritems == 0 && parent == root->node) {
2274
		BUG_ON(btrfs_header_level(root->node) != 1);
2275
		/* just turn the root into a leaf and break */
2276
		btrfs_set_header_level(root->node, 0);
2277
	} else if (slot == 0) {
2278 2279 2280 2281
		struct btrfs_disk_key disk_key;

		btrfs_node_key(parent, &disk_key, 0);
		wret = fixup_low_keys(trans, root, path, &disk_key, level + 1);
C
Chris Mason 已提交
2282 2283
		if (wret)
			ret = wret;
2284
	}
C
Chris Mason 已提交
2285
	btrfs_mark_buffer_dirty(parent);
C
Chris Mason 已提交
2286
	return ret;
2287 2288
}

C
Chris Mason 已提交
2289 2290 2291 2292
/*
 * delete the item at the leaf level in path.  If that empties
 * the leaf, remove it from the tree
 */
2293 2294
int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
		   struct btrfs_path *path)
2295 2296
{
	int slot;
2297 2298
	struct extent_buffer *leaf;
	struct btrfs_item *item;
2299 2300
	int doff;
	int dsize;
C
Chris Mason 已提交
2301 2302
	int ret = 0;
	int wret;
2303
	u32 nritems;
2304

2305
	leaf = path->nodes[0];
2306
	slot = path->slots[0];
2307 2308 2309
	doff = btrfs_item_offset_nr(leaf, slot);
	dsize = btrfs_item_size_nr(leaf, slot);
	nritems = btrfs_header_nritems(leaf);
2310

2311
	if (slot != nritems - 1) {
2312
		int i;
C
Chris Mason 已提交
2313
		int data_end = leaf_data_end(root, leaf);
2314 2315

		memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
C
Chris Mason 已提交
2316 2317 2318
			      data_end + dsize,
			      btrfs_leaf_data(leaf) + data_end,
			      doff - data_end);
2319

C
Chris Mason 已提交
2320
		for (i = slot + 1; i < nritems; i++) {
2321
			u32 ioff;
2322

2323
			item = btrfs_item_nr(leaf, i);
2324 2325 2326 2327 2328 2329 2330
			if (!leaf->map_token) {
				map_extent_buffer(leaf, (unsigned long)item,
					sizeof(struct btrfs_item),
					&leaf->map_token, &leaf->kaddr,
					&leaf->map_start, &leaf->map_len,
					KM_USER1);
			}
2331 2332
			ioff = btrfs_item_offset(leaf, item);
			btrfs_set_item_offset(leaf, item, ioff + dsize);
C
Chris Mason 已提交
2333
		}
2334 2335 2336 2337 2338 2339

		if (leaf->map_token) {
			unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
			leaf->map_token = NULL;
		}

2340 2341
		memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
			      btrfs_item_nr_offset(slot + 1),
C
Chris Mason 已提交
2342 2343
			      sizeof(struct btrfs_item) *
			      (nritems - slot - 1));
2344
	}
2345
	btrfs_set_header_nritems(leaf, nritems - 1);
2346
	nritems--;
2347

C
Chris Mason 已提交
2348
	/* delete the leaf if we've emptied it */
2349
	if (nritems == 0) {
2350 2351
		if (leaf == root->node) {
			btrfs_set_header_level(leaf, 0);
2352
		} else {
2353 2354
			clean_tree_block(trans, root, leaf);
			wait_on_tree_block_writeback(root, leaf);
2355
			wret = del_ptr(trans, root, path, 1, path->slots[1]);
C
Chris Mason 已提交
2356 2357
			if (wret)
				ret = wret;
2358
			wret = btrfs_free_extent(trans, root,
2359
						 leaf->start, leaf->len, 1);
C
Chris Mason 已提交
2360 2361
			if (wret)
				ret = wret;
2362
		}
2363
	} else {
2364
		int used = leaf_space_used(leaf, 0, nritems);
C
Chris Mason 已提交
2365
		if (slot == 0) {
2366 2367 2368
			struct btrfs_disk_key disk_key;

			btrfs_item_key(leaf, &disk_key, 0);
2369
			wret = fixup_low_keys(trans, root, path,
2370
					      &disk_key, 1);
C
Chris Mason 已提交
2371 2372 2373 2374
			if (wret)
				ret = wret;
		}

C
Chris Mason 已提交
2375
		/* delete the leaf if it is mostly empty */
C
Chris Mason 已提交
2376
		if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) {
2377 2378 2379 2380
			/* push_leaf_left fixes the path.
			 * make sure the path still points to our leaf
			 * for possible call to del_ptr below
			 */
2381
			slot = path->slots[1];
2382 2383
			extent_buffer_get(leaf);

2384
			wret = push_leaf_left(trans, root, path, 1);
2385
			if (wret < 0 && wret != -ENOSPC)
C
Chris Mason 已提交
2386
				ret = wret;
2387 2388 2389

			if (path->nodes[0] == leaf &&
			    btrfs_header_nritems(leaf)) {
2390
				wret = push_leaf_right(trans, root, path, 1);
2391
				if (wret < 0 && wret != -ENOSPC)
C
Chris Mason 已提交
2392 2393
					ret = wret;
			}
2394 2395

			if (btrfs_header_nritems(leaf) == 0) {
2396 2397
				u64 bytenr = leaf->start;
				u32 blocksize = leaf->len;
2398 2399 2400 2401

				clean_tree_block(trans, root, leaf);
				wait_on_tree_block_writeback(root, leaf);

2402
				wret = del_ptr(trans, root, path, 1, slot);
C
Chris Mason 已提交
2403 2404
				if (wret)
					ret = wret;
2405 2406

				free_extent_buffer(leaf);
2407 2408
				wret = btrfs_free_extent(trans, root, bytenr,
							 blocksize, 1);
C
Chris Mason 已提交
2409 2410
				if (wret)
					ret = wret;
C
Chris Mason 已提交
2411
			} else {
2412 2413
				btrfs_mark_buffer_dirty(leaf);
				free_extent_buffer(leaf);
2414
			}
2415
		} else {
2416
			btrfs_mark_buffer_dirty(leaf);
2417 2418
		}
	}
C
Chris Mason 已提交
2419
	return ret;
2420 2421
}

C
Chris Mason 已提交
2422 2423
/*
 * walk up the tree as far as required to find the next leaf.
C
Chris Mason 已提交
2424 2425
 * returns 0 if it found something or 1 if there are no greater leaves.
 * returns < 0 on io errors.
C
Chris Mason 已提交
2426
 */
C
Chris Mason 已提交
2427
int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
2428 2429 2430
{
	int slot;
	int level = 1;
2431
	u64 bytenr;
2432 2433
	struct extent_buffer *c;
	struct extent_buffer *next = NULL;
2434

C
Chris Mason 已提交
2435
	while(level < BTRFS_MAX_LEVEL) {
2436
		if (!path->nodes[level])
C
Chris Mason 已提交
2437
			return 1;
2438

2439 2440
		slot = path->slots[level] + 1;
		c = path->nodes[level];
2441
		if (slot >= btrfs_header_nritems(c)) {
2442 2443 2444
			level++;
			continue;
		}
2445

2446
		bytenr = btrfs_node_blockptr(c, slot);
C
Chris Mason 已提交
2447
		if (next)
2448 2449
			free_extent_buffer(next);

2450 2451
		if (path->reada)
			reada_for_search(root, path, level, slot);
2452

2453 2454
		next = read_tree_block(root, bytenr,
				       btrfs_level_size(root, level -1));
2455 2456 2457 2458 2459 2460
		break;
	}
	path->slots[level] = slot;
	while(1) {
		level--;
		c = path->nodes[level];
2461
		free_extent_buffer(c);
2462 2463 2464 2465
		path->nodes[level] = next;
		path->slots[level] = 0;
		if (!level)
			break;
2466
		if (path->reada)
Y
Yan 已提交
2467
			reada_for_search(root, path, level, 0);
2468 2469
		next = read_tree_block(root, btrfs_node_blockptr(next, 0),
				       btrfs_level_size(root, level - 1));
2470 2471 2472
	}
	return 0;
}