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Btrfs image tool
[btrfs-progs-unstable.git] / extent-tree.c
blob6a5194c5ebede6c286734ddbabc56ce7c5d78da9
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 <stdio.h>
20 #include <stdlib.h>
21 #include "kerncompat.h"
22 #include "radix-tree.h"
23 #include "ctree.h"
24 #include "disk-io.h"
25 #include "print-tree.h"
26 #include "transaction.h"
27 #include "crc32c.h"
28 #include "volumes.h"
29
30 #define BLOCK_GROUP_DATA EXTENT_WRITEBACK
31 #define BLOCK_GROUP_METADATA EXTENT_UPTODATE
32 #define BLOCK_GROUP_SYSTEM EXTENT_NEW
33
34 #define BLOCK_GROUP_DIRTY EXTENT_DIRTY
35
36 #define PENDING_EXTENT_INSERT 0
37 #define PENDING_EXTENT_DELETE 1
38 #define PENDING_BACKREF_UPDATE 2
39
40 struct pending_extent_op {
41 int type;
42 u64 bytenr;
43 u64 num_bytes;
44 u64 parent;
45 u64 orig_parent;
46 u64 generation;
47 u64 orig_generation;
48 int level;
49 };
50
51 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
52 btrfs_root *extent_root);
53 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
54 btrfs_root *extent_root);
55
56 void maybe_lock_mutex(struct btrfs_root *root)
57 {
58 }
59
60 void maybe_unlock_mutex(struct btrfs_root *root)
61 {
62 }
63
64 static int cache_block_group(struct btrfs_root *root,
65 struct btrfs_block_group_cache *block_group)
66 {
67 struct btrfs_path *path;
68 int ret;
69 struct btrfs_key key;
70 struct extent_buffer *leaf;
71 struct extent_io_tree *free_space_cache;
72 int slot;
73 u64 last = 0;
74 u64 hole_size;
75 u64 first_free;
76 int found = 0;
77
78 if (!block_group)
79 return 0;
80
81 root = root->fs_info->extent_root;
82 free_space_cache = &root->fs_info->free_space_cache;
83
84 if (block_group->cached)
85 return 0;
86
87 path = btrfs_alloc_path();
88 if (!path)
89 return -ENOMEM;
90
91 path->reada = 2;
92 first_free = block_group->key.objectid;
93 key.objectid = block_group->key.objectid;
94 key.offset = 0;
95 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
96 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
97 if (ret < 0)
98 return ret;
99 ret = btrfs_previous_item(root, path, 0, BTRFS_EXTENT_ITEM_KEY);
100 if (ret < 0)
101 return ret;
102 if (ret == 0) {
103 leaf = path->nodes[0];
104 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
105 if (key.objectid + key.offset > first_free)
106 first_free = key.objectid + key.offset;
107 }
108 while(1) {
109 leaf = path->nodes[0];
110 slot = path->slots[0];
111 if (slot >= btrfs_header_nritems(leaf)) {
112 ret = btrfs_next_leaf(root, path);
113 if (ret < 0)
114 goto err;
115 if (ret == 0) {
116 continue;
117 } else {
118 break;
119 }
120 }
121 btrfs_item_key_to_cpu(leaf, &key, slot);
122 if (key.objectid < block_group->key.objectid) {
123 goto next;
124 }
125 if (key.objectid >= block_group->key.objectid +
126 block_group->key.offset) {
127 break;
128 }
129
130 if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
131 if (!found) {
132 last = first_free;
133 found = 1;
134 }
135 if (key.objectid > last) {
136 hole_size = key.objectid - last;
137 set_extent_dirty(free_space_cache, last,
138 last + hole_size - 1,
139 GFP_NOFS);
140 }
141 last = key.objectid + key.offset;
142 }
143 next:
144 path->slots[0]++;
145 }
146
147 if (!found)
148 last = first_free;
149 if (block_group->key.objectid +
150 block_group->key.offset > last) {
151 hole_size = block_group->key.objectid +
152 block_group->key.offset - last;
153 set_extent_dirty(free_space_cache, last,
154 last + hole_size - 1, GFP_NOFS);
155 }
156 block_group->cached = 1;
157 err:
158 btrfs_free_path(path);
159 return 0;
160 }
161
162 struct btrfs_block_group_cache *btrfs_lookup_first_block_group(struct
163 btrfs_fs_info *info,
164 u64 bytenr)
165 {
166 struct extent_io_tree *block_group_cache;
167 struct btrfs_block_group_cache *block_group = NULL;
168 u64 ptr;
169 u64 start;
170 u64 end;
171 int ret;
172
173 bytenr = max_t(u64, bytenr,
174 BTRFS_SUPER_INFO_OFFSET + BTRFS_SUPER_INFO_SIZE);
175 block_group_cache = &info->block_group_cache;
176 ret = find_first_extent_bit(block_group_cache,
177 bytenr, &start, &end,
178 BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA |
179 BLOCK_GROUP_SYSTEM);
180 if (ret) {
181 return NULL;
182 }
183 ret = get_state_private(block_group_cache, start, &ptr);
184 if (ret)
185 return NULL;
186
187 block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
188 return block_group;
189 }
190
191 struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
192 btrfs_fs_info *info,
193 u64 bytenr)
194 {
195 struct extent_io_tree *block_group_cache;
196 struct btrfs_block_group_cache *block_group = NULL;
197 u64 ptr;
198 u64 start;
199 u64 end;
200 int ret;
201
202 block_group_cache = &info->block_group_cache;
203 ret = find_first_extent_bit(block_group_cache,
204 bytenr, &start, &end,
205 BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA |
206 BLOCK_GROUP_SYSTEM);
207 if (ret) {
208 return NULL;
209 }
210 ret = get_state_private(block_group_cache, start, &ptr);
211 if (ret)
212 return NULL;
213
214 block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
215 if (block_group->key.objectid <= bytenr && bytenr <
216 block_group->key.objectid + block_group->key.offset)
217 return block_group;
218 return NULL;
219 }
220
221 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
222 {
223 return (cache->flags & bits) == bits;
224 }
225
226 static int noinline find_search_start(struct btrfs_root *root,
227 struct btrfs_block_group_cache **cache_ret,
228 u64 *start_ret, int num, int data)
229 {
230 int ret;
231 struct btrfs_block_group_cache *cache = *cache_ret;
232 u64 last;
233 u64 start = 0;
234 u64 end = 0;
235 u64 search_start = *start_ret;
236 int wrapped = 0;
237
238 if (!cache) {
239 goto out;
240 }
241 again:
242 ret = cache_block_group(root, cache);
243 if (ret)
244 goto out;
245
246 last = max(search_start, cache->key.objectid);
247 if (cache->ro || !block_group_bits(cache, data)) {
248 goto new_group;
249 }
250
251 while(1) {
252 ret = find_first_extent_bit(&root->fs_info->free_space_cache,
253 last, &start, &end, EXTENT_DIRTY);
254 if (ret) {
255 goto new_group;
256 }
257
258 start = max(last, start);
259 last = end + 1;
260 if (last - start < num) {
261 continue;
262 }
263 if (start + num > cache->key.objectid + cache->key.offset) {
264 goto new_group;
265 }
266 *start_ret = start;
267 return 0;
268 }
269 out:
270 cache = btrfs_lookup_block_group(root->fs_info, search_start);
271 if (!cache) {
272 printk("Unable to find block group for %llu\n",
273 (unsigned long long)search_start);
274 WARN_ON(1);
275 }
276 return -ENOSPC;
277
278 new_group:
279 last = cache->key.objectid + cache->key.offset;
280 wrapped:
281 cache = btrfs_lookup_first_block_group(root->fs_info, last);
282 if (!cache) {
283 no_cache:
284 if (!wrapped) {
285 wrapped = 1;
286 last = search_start;
287 goto wrapped;
288 }
289 goto out;
290 }
291 cache = btrfs_find_block_group(root, cache, last, data, 0);
292 cache = btrfs_find_block_group(root, cache, last, data, 0);
293 if (!cache)
294 goto no_cache;
295
296 *cache_ret = cache;
297 goto again;
298 }
299
300 static u64 div_factor(u64 num, int factor)
301 {
302 if (factor == 10)
303 return num;
304 num *= factor;
305 num /= 10;
306 return num;
307 }
308
309 static int block_group_state_bits(u64 flags)
310 {
311 int bits = 0;
312 if (flags & BTRFS_BLOCK_GROUP_DATA)
313 bits |= BLOCK_GROUP_DATA;
314 if (flags & BTRFS_BLOCK_GROUP_METADATA)
315 bits |= BLOCK_GROUP_METADATA;
316 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
317 bits |= BLOCK_GROUP_SYSTEM;
318 return bits;
319 }
320
321 struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
322 struct btrfs_block_group_cache
323 *hint, u64 search_start,
324 int data, int owner)
325 {
326 struct btrfs_block_group_cache *cache;
327 struct extent_io_tree *block_group_cache;
328 struct btrfs_block_group_cache *found_group = NULL;
329 struct btrfs_fs_info *info = root->fs_info;
330 u64 used;
331 u64 last = 0;
332 u64 hint_last;
333 u64 start;
334 u64 end;
335 u64 free_check;
336 u64 ptr;
337 int bit;
338 int ret;
339 int full_search = 0;
340 int factor = 10;
341
342 block_group_cache = &info->block_group_cache;
343
344 if (!owner)
345 factor = 10;
346
347 bit = block_group_state_bits(data);
348
349 if (search_start) {
350 struct btrfs_block_group_cache *shint;
351 shint = btrfs_lookup_block_group(info, search_start);
352 if (shint && !shint->ro && block_group_bits(shint, data)) {
353 used = btrfs_block_group_used(&shint->item);
354 if (used + shint->pinned <
355 div_factor(shint->key.offset, factor)) {
356 return shint;
357 }
358 }
359 }
360 if (hint && !hint->ro && block_group_bits(hint, data)) {
361 used = btrfs_block_group_used(&hint->item);
362 if (used + hint->pinned <
363 div_factor(hint->key.offset, factor)) {
364 return hint;
365 }
366 last = hint->key.objectid + hint->key.offset;
367 hint_last = last;
368 } else {
369 if (hint)
370 hint_last = max(hint->key.objectid, search_start);
371 else
372 hint_last = search_start;
373
374 last = hint_last;
375 }
376 again:
377 while(1) {
378 ret = find_first_extent_bit(block_group_cache, last,
379 &start, &end, bit);
380 if (ret)
381 break;
382
383 ret = get_state_private(block_group_cache, start, &ptr);
384 if (ret)
385 break;
386
387 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
388 last = cache->key.objectid + cache->key.offset;
389 used = btrfs_block_group_used(&cache->item);
390
391 if (!cache->ro && block_group_bits(cache, data)) {
392 if (full_search)
393 free_check = cache->key.offset;
394 else
395 free_check = div_factor(cache->key.offset,
396 factor);
397
398 if (used + cache->pinned < free_check) {
399 found_group = cache;
400 goto found;
401 }
402 }
403 cond_resched();
404 }
405 if (!full_search) {
406 last = search_start;
407 full_search = 1;
408 goto again;
409 }
410 found:
411 return found_group;
412 }
413
414 /*
415 * Back reference rules. Back refs have three main goals:
416 *
417 * 1) differentiate between all holders of references to an extent so that
418 * when a reference is dropped we can make sure it was a valid reference
419 * before freeing the extent.
420 *
421 * 2) Provide enough information to quickly find the holders of an extent
422 * if we notice a given block is corrupted or bad.
423 *
424 * 3) Make it easy to migrate blocks for FS shrinking or storage pool
425 * maintenance. This is actually the same as #2, but with a slightly
426 * different use case.
427 *
428 * File extents can be referenced by:
429 *
430 * - multiple snapshots, subvolumes, or different generations in one subvol
431 * - different files inside a single subvolume
432 * - different offsets inside a file (bookend extents in file.c)
433 *
434 * The extent ref structure has fields for:
435 *
436 * - Objectid of the subvolume root
437 * - Generation number of the tree holding the reference
438 * - objectid of the file holding the reference
439 * - offset in the file corresponding to the key holding the reference
440 * - number of references holding by parent node (alway 1 for tree blocks)
441 *
442 * Btree leaf may hold multiple references to a file extent. In most cases,
443 * these references are from same file and the corresponding offsets inside
444 * the file are close together. So inode objectid and offset in file are
445 * just hints, they provide hints about where in the btree the references
446 * can be found and when we can stop searching.
447 *
448 * When a file extent is allocated the fields are filled in:
449 * (root_key.objectid, trans->transid, inode objectid, offset in file, 1)
450 *
451 * When a leaf is cow'd new references are added for every file extent found
452 * in the leaf. It looks similar to the create case, but trans->transid will
453 * be different when the block is cow'd.
454 *
455 * (root_key.objectid, trans->transid, inode objectid, offset in file,
456 * number of references in the leaf)
457 *
458 * Because inode objectid and offset in file are just hints, they are not
459 * used when backrefs are deleted. When a file extent is removed either
460 * during snapshot deletion or file truncation, we find the corresponding
461 * back back reference and check the following fields.
462 *
463 * (btrfs_header_owner(leaf), btrfs_header_generation(leaf))
464 *
465 * Btree extents can be referenced by:
466 *
467 * - Different subvolumes
468 * - Different generations of the same subvolume
469 *
470 * When a tree block is created, back references are inserted:
471 *
472 * (root->root_key.objectid, trans->transid, level, 0, 1)
473 *
474 * When a tree block is cow'd, new back references are added for all the
475 * blocks it points to. If the tree block isn't in reference counted root,
476 * the old back references are removed. These new back references are of
477 * the form (trans->transid will have increased since creation):
478 *
479 * (root->root_key.objectid, trans->transid, level, 0, 1)
480 *
481 * When a backref is in deleting, the following fields are checked:
482 *
483 * if backref was for a tree root:
484 * (btrfs_header_owner(itself), btrfs_header_generation(itself))
485 * else
486 * (btrfs_header_owner(parent), btrfs_header_generation(parent))
487 *
488 * Back Reference Key composing:
489 *
490 * The key objectid corresponds to the first byte in the extent, the key
491 * type is set to BTRFS_EXTENT_REF_KEY, and the key offset is the first
492 * byte of parent extent. If a extent is tree root, the key offset is set
493 * to the key objectid.
494 */
495
496 static int noinline lookup_extent_backref(struct btrfs_trans_handle *trans,
497 struct btrfs_root *root,
498 struct btrfs_path *path,
499 u64 bytenr, u64 parent,
500 u64 ref_root, u64 ref_generation,
501 u64 owner_objectid, int del)
502 {
503 struct btrfs_key key;
504 struct btrfs_extent_ref *ref;
505 struct extent_buffer *leaf;
506 u64 ref_objectid;
507 int ret;
508
509 key.objectid = bytenr;
510 key.type = BTRFS_EXTENT_REF_KEY;
511 key.offset = parent;
512
513 ret = btrfs_search_slot(trans, root, &key, path, del ? -1 : 0, 1);
514 if (ret < 0)
515 goto out;
516 if (ret > 0) {
517 ret = -ENOENT;
518 goto out;
519 }
520
521 leaf = path->nodes[0];
522 ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref);
523 ref_objectid = btrfs_ref_objectid(leaf, ref);
524 if (btrfs_ref_root(leaf, ref) != ref_root ||
525 btrfs_ref_generation(leaf, ref) != ref_generation ||
526 (ref_objectid != owner_objectid &&
527 ref_objectid != BTRFS_MULTIPLE_OBJECTIDS)) {
528 ret = -EIO;
529 WARN_ON(1);
530 goto out;
531 }
532 ret = 0;
533 out:
534 return ret;
535 }
536
537 static int noinline insert_extent_backref(struct btrfs_trans_handle *trans,
538 struct btrfs_root *root,
539 struct btrfs_path *path,
540 u64 bytenr, u64 parent,
541 u64 ref_root, u64 ref_generation,
542 u64 owner_objectid)
543 {
544 struct btrfs_key key;
545 struct extent_buffer *leaf;
546 struct btrfs_extent_ref *ref;
547 u32 num_refs;
548 int ret;
549
550 key.objectid = bytenr;
551 key.type = BTRFS_EXTENT_REF_KEY;
552 key.offset = parent;
553
554 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*ref));
555 if (ret == 0) {
556 leaf = path->nodes[0];
557 ref = btrfs_item_ptr(leaf, path->slots[0],
558 struct btrfs_extent_ref);
559 btrfs_set_ref_root(leaf, ref, ref_root);
560 btrfs_set_ref_generation(leaf, ref, ref_generation);
561 btrfs_set_ref_objectid(leaf, ref, owner_objectid);
562 btrfs_set_ref_num_refs(leaf, ref, 1);
563 } else if (ret == -EEXIST) {
564 u64 existing_owner;
565 BUG_ON(owner_objectid < BTRFS_FIRST_FREE_OBJECTID);
566 leaf = path->nodes[0];
567 ref = btrfs_item_ptr(leaf, path->slots[0],
568 struct btrfs_extent_ref);
569 if (btrfs_ref_root(leaf, ref) != ref_root ||
570 btrfs_ref_generation(leaf, ref) != ref_generation) {
571 ret = -EIO;
572 WARN_ON(1);
573 goto out;
574 }
575
576 num_refs = btrfs_ref_num_refs(leaf, ref);
577 BUG_ON(num_refs == 0);
578 btrfs_set_ref_num_refs(leaf, ref, num_refs + 1);
579
580 existing_owner = btrfs_ref_objectid(leaf, ref);
581 if (existing_owner != owner_objectid &&
582 existing_owner != BTRFS_MULTIPLE_OBJECTIDS) {
583 btrfs_set_ref_objectid(leaf, ref,
584 BTRFS_MULTIPLE_OBJECTIDS);
585 }
586 ret = 0;
587 } else {
588 goto out;
589 }
590 btrfs_mark_buffer_dirty(path->nodes[0]);
591 out:
592 btrfs_release_path(root, path);
593 return ret;
594 }
595
596 static int noinline remove_extent_backref(struct btrfs_trans_handle *trans,
597 struct btrfs_root *root,
598 struct btrfs_path *path)
599 {
600 struct extent_buffer *leaf;
601 struct btrfs_extent_ref *ref;
602 u32 num_refs;
603 int ret = 0;
604
605 leaf = path->nodes[0];
606 ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref);
607 num_refs = btrfs_ref_num_refs(leaf, ref);
608 BUG_ON(num_refs == 0);
609 num_refs -= 1;
610 if (num_refs == 0) {
611 ret = btrfs_del_item(trans, root, path);
612 } else {
613 btrfs_set_ref_num_refs(leaf, ref, num_refs);
614 btrfs_mark_buffer_dirty(leaf);
615 }
616 btrfs_release_path(root, path);
617 return ret;
618 }
619
620 static int __btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
621 struct btrfs_root *root, u64 bytenr,
622 u64 orig_parent, u64 parent,
623 u64 orig_root, u64 ref_root,
624 u64 orig_generation, u64 ref_generation,
625 u64 owner_objectid)
626 {
627 int ret;
628 struct btrfs_root *extent_root = root->fs_info->extent_root;
629 struct btrfs_path *path;
630
631 if (root == root->fs_info->extent_root) {
632 struct pending_extent_op *extent_op;
633 u64 num_bytes;
634
635 BUG_ON(owner_objectid >= BTRFS_MAX_LEVEL);
636 num_bytes = btrfs_level_size(root, (int)owner_objectid);
637 if (test_range_bit(&root->fs_info->extent_ins, bytenr,
638 bytenr + num_bytes - 1, EXTENT_LOCKED, 0)) {
639 u64 priv;
640 ret = get_state_private(&root->fs_info->extent_ins,
641 bytenr, &priv);
642 BUG_ON(ret);
643 extent_op = (struct pending_extent_op *)
644 (unsigned long)priv;
645 BUG_ON(extent_op->parent != orig_parent);
646 BUG_ON(extent_op->generation != orig_generation);
647 extent_op->parent = parent;
648 extent_op->generation = ref_generation;
649 } else {
650 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
651 BUG_ON(!extent_op);
652
653 extent_op->type = PENDING_BACKREF_UPDATE;
654 extent_op->bytenr = bytenr;
655 extent_op->num_bytes = num_bytes;
656 extent_op->parent = parent;
657 extent_op->orig_parent = orig_parent;
658 extent_op->generation = ref_generation;
659 extent_op->orig_generation = orig_generation;
660 extent_op->level = (int)owner_objectid;
661
662 set_extent_bits(&root->fs_info->extent_ins,
663 bytenr, bytenr + num_bytes - 1,
664 EXTENT_LOCKED, GFP_NOFS);
665 set_state_private(&root->fs_info->extent_ins,
666 bytenr, (unsigned long)extent_op);
667 }
668 return 0;
669 }
670
671 path = btrfs_alloc_path();
672 if (!path)
673 return -ENOMEM;
674 ret = lookup_extent_backref(trans, extent_root, path,
675 bytenr, orig_parent, orig_root,
676 orig_generation, owner_objectid, 1);
677 if (ret)
678 goto out;
679 ret = remove_extent_backref(trans, extent_root, path);
680 if (ret)
681 goto out;
682 ret = insert_extent_backref(trans, extent_root, path, bytenr,
683 parent, ref_root, ref_generation,
684 owner_objectid);
685 BUG_ON(ret);
686 finish_current_insert(trans, extent_root);
687 del_pending_extents(trans, extent_root);
688 out:
689 btrfs_free_path(path);
690 return ret;
691 }
692
693 int btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
694 struct btrfs_root *root, u64 bytenr,
695 u64 orig_parent, u64 parent,
696 u64 ref_root, u64 ref_generation,
697 u64 owner_objectid)
698 {
699 int ret;
700 if (ref_root == BTRFS_TREE_LOG_OBJECTID &&
701 owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
702 return 0;
703 maybe_lock_mutex(root);
704 ret = __btrfs_update_extent_ref(trans, root, bytenr, orig_parent,
705 parent, ref_root, ref_root,
706 ref_generation, ref_generation,
707 owner_objectid);
708 maybe_unlock_mutex(root);
709 return ret;
710 }
711
712 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
713 struct btrfs_root *root, u64 bytenr,
714 u64 orig_parent, u64 parent,
715 u64 orig_root, u64 ref_root,
716 u64 orig_generation, u64 ref_generation,
717 u64 owner_objectid)
718 {
719 struct btrfs_path *path;
720 int ret;
721 struct btrfs_key key;
722 struct extent_buffer *l;
723 struct btrfs_extent_item *item;
724 u32 refs;
725
726 path = btrfs_alloc_path();
727 if (!path)
728 return -ENOMEM;
729
730 path->reada = 1;
731 key.objectid = bytenr;
732 key.type = BTRFS_EXTENT_ITEM_KEY;
733 key.offset = (u64)-1;
734
735 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
736 0, 1);
737 if (ret < 0)
738 return ret;
739 BUG_ON(ret == 0 || path->slots[0] == 0);
740
741 path->slots[0]--;
742 l = path->nodes[0];
743
744 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
745 BUG_ON(key.objectid != bytenr);
746 BUG_ON(key.type != BTRFS_EXTENT_ITEM_KEY);
747
748 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
749 refs = btrfs_extent_refs(l, item);
750 btrfs_set_extent_refs(l, item, refs + 1);
751 btrfs_mark_buffer_dirty(path->nodes[0]);
752
753 btrfs_release_path(root->fs_info->extent_root, path);
754
755 path->reada = 1;
756 ret = insert_extent_backref(trans, root->fs_info->extent_root,
757 path, bytenr, parent,
758 ref_root, ref_generation,
759 owner_objectid);
760 BUG_ON(ret);
761 finish_current_insert(trans, root->fs_info->extent_root);
762 del_pending_extents(trans, root->fs_info->extent_root);
763
764 btrfs_free_path(path);
765 return 0;
766 }
767
768 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
769 struct btrfs_root *root,
770 u64 bytenr, u64 num_bytes, u64 parent,
771 u64 ref_root, u64 ref_generation,
772 u64 owner_objectid)
773 {
774 int ret;
775 if (ref_root == BTRFS_TREE_LOG_OBJECTID &&
776 owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
777 return 0;
778 maybe_lock_mutex(root);
779 ret = __btrfs_inc_extent_ref(trans, root, bytenr, 0, parent,
780 0, ref_root, 0, ref_generation,
781 owner_objectid);
782 maybe_unlock_mutex(root);
783 return ret;
784 }
785
786 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
787 struct btrfs_root *root)
788 {
789 finish_current_insert(trans, root->fs_info->extent_root);
790 del_pending_extents(trans, root->fs_info->extent_root);
791 return 0;
792 }
793
794 int lookup_extent_ref(struct btrfs_trans_handle *trans,
795 struct btrfs_root *root, u64 bytenr,
796 u64 num_bytes, u32 *refs)
797 {
798 struct btrfs_path *path;
799 int ret;
800 struct btrfs_key key;
801 struct extent_buffer *l;
802 struct btrfs_extent_item *item;
803
804 WARN_ON(num_bytes < root->sectorsize);
805 path = btrfs_alloc_path();
806 path->reada = 1;
807 key.objectid = bytenr;
808 key.offset = num_bytes;
809 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
810 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
811 0, 0);
812 if (ret < 0)
813 goto out;
814 if (ret != 0) {
815 btrfs_print_leaf(root, path->nodes[0]);
816 printk("failed to find block number %Lu\n", bytenr);
817 BUG();
818 }
819 l = path->nodes[0];
820 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
821 *refs = btrfs_extent_refs(l, item);
822 out:
823 btrfs_free_path(path);
824 return 0;
825 }
826
827 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
828 struct extent_buffer *orig_buf, struct extent_buffer *buf,
829 u32 *nr_extents)
830 {
831 u64 bytenr;
832 u64 ref_root;
833 u64 orig_root;
834 u64 ref_generation;
835 u64 orig_generation;
836 u32 nritems;
837 u32 nr_file_extents = 0;
838 struct btrfs_key key;
839 struct btrfs_file_extent_item *fi;
840 int i;
841 int level;
842 int ret = 0;
843 int faili = 0;
844 int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
845 u64, u64, u64, u64, u64, u64, u64, u64);
846
847 ref_root = btrfs_header_owner(buf);
848 ref_generation = btrfs_header_generation(buf);
849 orig_root = btrfs_header_owner(orig_buf);
850 orig_generation = btrfs_header_generation(orig_buf);
851
852 nritems = btrfs_header_nritems(buf);
853 level = btrfs_header_level(buf);
854
855 if (root->ref_cows) {
856 process_func = __btrfs_inc_extent_ref;
857 } else {
858 if (level == 0 &&
859 root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
860 goto out;
861 process_func = __btrfs_update_extent_ref;
862 }
863
864 for (i = 0; i < nritems; i++) {
865 cond_resched();
866 if (level == 0) {
867 btrfs_item_key_to_cpu(buf, &key, i);
868 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
869 continue;
870 fi = btrfs_item_ptr(buf, i,
871 struct btrfs_file_extent_item);
872 if (btrfs_file_extent_type(buf, fi) ==
873 BTRFS_FILE_EXTENT_INLINE)
874 continue;
875 bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
876 if (bytenr == 0)
877 continue;
878
879 nr_file_extents++;
880
881 maybe_lock_mutex(root);
882 ret = process_func(trans, root, bytenr,
883 orig_buf->start, buf->start,
884 orig_root, ref_root,
885 orig_generation, ref_generation,
886 key.objectid);
887 maybe_unlock_mutex(root);
888
889 if (ret) {
890 faili = i;
891 WARN_ON(1);
892 goto fail;
893 }
894 } else {
895 bytenr = btrfs_node_blockptr(buf, i);
896 maybe_lock_mutex(root);
897 ret = process_func(trans, root, bytenr,
898 orig_buf->start, buf->start,
899 orig_root, ref_root,
900 orig_generation, ref_generation,
901 level - 1);
902 maybe_unlock_mutex(root);
903 if (ret) {
904 faili = i;
905 WARN_ON(1);
906 goto fail;
907 }
908 }
909 }
910 out:
911 if (nr_extents) {
912 if (level == 0)
913 *nr_extents = nr_file_extents;
914 else
915 *nr_extents = nritems;
916 }
917 return 0;
918 fail:
919 WARN_ON(1);
920 #if 0
921 for (i =0; i < faili; i++) {
922 if (level == 0) {
923 u64 disk_bytenr;
924 btrfs_item_key_to_cpu(buf, &key, i);
925 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
926 continue;
927 fi = btrfs_item_ptr(buf, i,
928 struct btrfs_file_extent_item);
929 if (btrfs_file_extent_type(buf, fi) ==
930 BTRFS_FILE_EXTENT_INLINE)
931 continue;
932 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
933 if (disk_bytenr == 0)
934 continue;
935 err = btrfs_free_extent(trans, root, disk_bytenr,
936 btrfs_file_extent_disk_num_bytes(buf,
937 fi), 0);
938 BUG_ON(err);
939 } else {
940 bytenr = btrfs_node_blockptr(buf, i);
941 err = btrfs_free_extent(trans, root, bytenr,
942 btrfs_level_size(root, level - 1), 0);
943 BUG_ON(err);
944 }
945 }
946 #endif
947 return ret;
948 }
949
950 int btrfs_update_ref(struct btrfs_trans_handle *trans,
951 struct btrfs_root *root, struct extent_buffer *orig_buf,
952 struct extent_buffer *buf, int start_slot, int nr)
953
954 {
955 u64 bytenr;
956 u64 ref_root;
957 u64 orig_root;
958 u64 ref_generation;
959 u64 orig_generation;
960 struct btrfs_key key;
961 struct btrfs_file_extent_item *fi;
962 int i;
963 int ret;
964 int slot;
965 int level;
966
967 BUG_ON(start_slot < 0);
968 BUG_ON(start_slot + nr > btrfs_header_nritems(buf));
969
970 ref_root = btrfs_header_owner(buf);
971 ref_generation = btrfs_header_generation(buf);
972 orig_root = btrfs_header_owner(orig_buf);
973 orig_generation = btrfs_header_generation(orig_buf);
974 level = btrfs_header_level(buf);
975
976 if (!root->ref_cows) {
977 if (level == 0 &&
978 root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
979 return 0;
980 }
981
982 for (i = 0, slot = start_slot; i < nr; i++, slot++) {
983 cond_resched();
984 if (level == 0) {
985 btrfs_item_key_to_cpu(buf, &key, slot);
986 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
987 continue;
988 fi = btrfs_item_ptr(buf, slot,
989 struct btrfs_file_extent_item);
990 if (btrfs_file_extent_type(buf, fi) ==
991 BTRFS_FILE_EXTENT_INLINE)
992 continue;
993 bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
994 if (bytenr == 0)
995 continue;
996
997 maybe_lock_mutex(root);
998 ret = __btrfs_update_extent_ref(trans, root, bytenr,
999 orig_buf->start, buf->start,
1000 orig_root, ref_root,
1001 orig_generation, ref_generation,
1002 key.objectid);
1003 maybe_unlock_mutex(root);
1004 if (ret)
1005 goto fail;
1006 } else {
1007 bytenr = btrfs_node_blockptr(buf, slot);
1008 maybe_lock_mutex(root);
1009 ret = __btrfs_update_extent_ref(trans, root, bytenr,
1010 orig_buf->start, buf->start,
1011 orig_root, ref_root,
1012 orig_generation, ref_generation,
1013 level - 1);
1014 maybe_unlock_mutex(root);
1015 if (ret)
1016 goto fail;
1017 }
1018 }
1019 return 0;
1020 fail:
1021 WARN_ON(1);
1022 return -1;
1023 }
1024
1025 static int write_one_cache_group(struct btrfs_trans_handle *trans,
1026 struct btrfs_root *root,
1027 struct btrfs_path *path,
1028 struct btrfs_block_group_cache *cache)
1029 {
1030 int ret;
1031 int pending_ret;
1032 struct btrfs_root *extent_root = root->fs_info->extent_root;
1033 unsigned long bi;
1034 struct extent_buffer *leaf;
1035
1036 ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
1037 if (ret < 0)
1038 goto fail;
1039 BUG_ON(ret);
1040
1041 leaf = path->nodes[0];
1042 bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
1043 write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
1044 btrfs_mark_buffer_dirty(leaf);
1045 btrfs_release_path(extent_root, path);
1046 fail:
1047 finish_current_insert(trans, extent_root);
1048 pending_ret = del_pending_extents(trans, extent_root);
1049 if (ret)
1050 return ret;
1051 if (pending_ret)
1052 return pending_ret;
1053 return 0;
1054
1055 }
1056
1057 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
1058 struct btrfs_root *root)
1059 {
1060 struct extent_io_tree *block_group_cache;
1061 struct btrfs_block_group_cache *cache;
1062 int ret;
1063 int err = 0;
1064 int werr = 0;
1065 struct btrfs_path *path;
1066 u64 last = 0;
1067 u64 start;
1068 u64 end;
1069 u64 ptr;
1070
1071 block_group_cache = &root->fs_info->block_group_cache;
1072 path = btrfs_alloc_path();
1073 if (!path)
1074 return -ENOMEM;
1075
1076 while(1) {
1077 ret = find_first_extent_bit(block_group_cache, last,
1078 &start, &end, BLOCK_GROUP_DIRTY);
1079 if (ret)
1080 break;
1081
1082 last = end + 1;
1083 ret = get_state_private(block_group_cache, start, &ptr);
1084 if (ret)
1085 break;
1086 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
1087 err = write_one_cache_group(trans, root,
1088 path, cache);
1089 /*
1090 * if we fail to write the cache group, we want
1091 * to keep it marked dirty in hopes that a later
1092 * write will work
1093 */
1094 if (err) {
1095 werr = err;
1096 continue;
1097 }
1098 clear_extent_bits(block_group_cache, start, end,
1099 BLOCK_GROUP_DIRTY, GFP_NOFS);
1100 }
1101 btrfs_free_path(path);
1102 return werr;
1103 }
1104
1105 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
1106 u64 flags)
1107 {
1108 struct list_head *head = &info->space_info;
1109 struct list_head *cur;
1110 struct btrfs_space_info *found;
1111 list_for_each(cur, head) {
1112 found = list_entry(cur, struct btrfs_space_info, list);
1113 if (found->flags == flags)
1114 return found;
1115 }
1116 return NULL;
1117
1118 }
1119
1120 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
1121 u64 total_bytes, u64 bytes_used,
1122 struct btrfs_space_info **space_info)
1123 {
1124 struct btrfs_space_info *found;
1125
1126 found = __find_space_info(info, flags);
1127 if (found) {
1128 found->total_bytes += total_bytes;
1129 found->bytes_used += bytes_used;
1130 WARN_ON(found->total_bytes < found->bytes_used);
1131 *space_info = found;
1132 return 0;
1133 }
1134 found = kmalloc(sizeof(*found), GFP_NOFS);
1135 if (!found)
1136 return -ENOMEM;
1137
1138 list_add(&found->list, &info->space_info);
1139 found->flags = flags;
1140 found->total_bytes = total_bytes;
1141 found->bytes_used = bytes_used;
1142 found->bytes_pinned = 0;
1143 found->full = 0;
1144 *space_info = found;
1145 return 0;
1146 }
1147
1148
1149 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
1150 {
1151 u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
1152 BTRFS_BLOCK_GROUP_RAID1 |
1153 BTRFS_BLOCK_GROUP_DUP);
1154 if (extra_flags) {
1155 if (flags & BTRFS_BLOCK_GROUP_DATA)
1156 fs_info->avail_data_alloc_bits |= extra_flags;
1157 if (flags & BTRFS_BLOCK_GROUP_METADATA)
1158 fs_info->avail_metadata_alloc_bits |= extra_flags;
1159 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
1160 fs_info->avail_system_alloc_bits |= extra_flags;
1161 }
1162 }
1163
1164 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
1165 struct btrfs_root *extent_root, u64 alloc_bytes,
1166 u64 flags)
1167 {
1168 struct btrfs_space_info *space_info;
1169 u64 thresh;
1170 u64 start;
1171 u64 num_bytes;
1172 int ret;
1173
1174 space_info = __find_space_info(extent_root->fs_info, flags);
1175 if (!space_info) {
1176 ret = update_space_info(extent_root->fs_info, flags,
1177 0, 0, &space_info);
1178 BUG_ON(ret);
1179 }
1180 BUG_ON(!space_info);
1181
1182 if (space_info->full)
1183 return 0;
1184
1185 thresh = div_factor(space_info->total_bytes, 7);
1186 if ((space_info->bytes_used + space_info->bytes_pinned + alloc_bytes) <
1187 thresh)
1188 return 0;
1189
1190 ret = btrfs_alloc_chunk(trans, extent_root, &start, &num_bytes, flags);
1191 if (ret == -ENOSPC) {
1192 space_info->full = 1;
1193 return 0;
1194 }
1195
1196 BUG_ON(ret);
1197
1198 ret = btrfs_make_block_group(trans, extent_root, 0, flags,
1199 BTRFS_FIRST_CHUNK_TREE_OBJECTID, start, num_bytes);
1200 BUG_ON(ret);
1201 return 0;
1202 }
1203
1204 static int update_block_group(struct btrfs_trans_handle *trans,
1205 struct btrfs_root *root,
1206 u64 bytenr, u64 num_bytes, int alloc,
1207 int mark_free)
1208 {
1209 struct btrfs_block_group_cache *cache;
1210 struct btrfs_fs_info *info = root->fs_info;
1211 u64 total = num_bytes;
1212 u64 old_val;
1213 u64 byte_in_group;
1214 u64 start;
1215 u64 end;
1216
1217 while(total) {
1218 cache = btrfs_lookup_block_group(info, bytenr);
1219 if (!cache) {
1220 return -1;
1221 }
1222 byte_in_group = bytenr - cache->key.objectid;
1223 WARN_ON(byte_in_group > cache->key.offset);
1224 start = cache->key.objectid;
1225 end = start + cache->key.offset - 1;
1226 set_extent_bits(&info->block_group_cache, start, end,
1227 BLOCK_GROUP_DIRTY, GFP_NOFS);
1228
1229 old_val = btrfs_block_group_used(&cache->item);
1230 num_bytes = min(total, cache->key.offset - byte_in_group);
1231 if (alloc) {
1232 old_val += num_bytes;
1233 cache->space_info->bytes_used += num_bytes;
1234 } else {
1235 old_val -= num_bytes;
1236 cache->space_info->bytes_used -= num_bytes;
1237 if (mark_free) {
1238 set_extent_dirty(&info->free_space_cache,
1239 bytenr, bytenr + num_bytes - 1,
1240 GFP_NOFS);
1241 }
1242 }
1243 btrfs_set_block_group_used(&cache->item, old_val);
1244 total -= num_bytes;
1245 bytenr += num_bytes;
1246 }
1247 return 0;
1248 }
1249
1250 static int update_pinned_extents(struct btrfs_root *root,
1251 u64 bytenr, u64 num, int pin)
1252 {
1253 u64 len;
1254 struct btrfs_block_group_cache *cache;
1255 struct btrfs_fs_info *fs_info = root->fs_info;
1256
1257 if (pin) {
1258 set_extent_dirty(&fs_info->pinned_extents,
1259 bytenr, bytenr + num - 1, GFP_NOFS);
1260 } else {
1261 clear_extent_dirty(&fs_info->pinned_extents,
1262 bytenr, bytenr + num - 1, GFP_NOFS);
1263 }
1264 while (num > 0) {
1265 cache = btrfs_lookup_block_group(fs_info, bytenr);
1266 WARN_ON(!cache);
1267 len = min(num, cache->key.offset -
1268 (bytenr - cache->key.objectid));
1269 if (pin) {
1270 cache->pinned += len;
1271 cache->space_info->bytes_pinned += len;
1272 fs_info->total_pinned += len;
1273 } else {
1274 cache->pinned -= len;
1275 cache->space_info->bytes_pinned -= len;
1276 fs_info->total_pinned -= len;
1277 }
1278 bytenr += len;
1279 num -= len;
1280 }
1281 return 0;
1282 }
1283
1284 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
1285 {
1286 u64 last = 0;
1287 u64 start;
1288 u64 end;
1289 struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
1290 int ret;
1291
1292 while(1) {
1293 ret = find_first_extent_bit(pinned_extents, last,
1294 &start, &end, EXTENT_DIRTY);
1295 if (ret)
1296 break;
1297 set_extent_dirty(copy, start, end, GFP_NOFS);
1298 last = end + 1;
1299 }
1300 return 0;
1301 }
1302
1303 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
1304 struct btrfs_root *root,
1305 struct extent_io_tree *unpin)
1306 {
1307 u64 start;
1308 u64 end;
1309 int ret;
1310 struct extent_io_tree *free_space_cache;
1311 free_space_cache = &root->fs_info->free_space_cache;
1312
1313 while(1) {
1314 ret = find_first_extent_bit(unpin, 0, &start, &end,
1315 EXTENT_DIRTY);
1316 if (ret)
1317 break;
1318 update_pinned_extents(root, start, end + 1 - start, 0);
1319 clear_extent_dirty(unpin, start, end, GFP_NOFS);
1320 set_extent_dirty(free_space_cache, start, end, GFP_NOFS);
1321 }
1322 return 0;
1323 }
1324
1325 static int finish_current_insert(struct btrfs_trans_handle *trans,
1326 struct btrfs_root *extent_root)
1327 {
1328 u64 start;
1329 u64 end;
1330 u64 priv;
1331 struct btrfs_fs_info *info = extent_root->fs_info;
1332 struct btrfs_path *path;
1333 struct btrfs_extent_ref *ref;
1334 struct pending_extent_op *extent_op;
1335 struct btrfs_key key;
1336 struct btrfs_extent_item extent_item;
1337 int ret;
1338 int err = 0;
1339
1340 btrfs_set_stack_extent_refs(&extent_item, 1);
1341 path = btrfs_alloc_path();
1342
1343 while(1) {
1344 ret = find_first_extent_bit(&info->extent_ins, 0, &start,
1345 &end, EXTENT_LOCKED);
1346 if (ret)
1347 break;
1348
1349 ret = get_state_private(&info->extent_ins, start, &priv);
1350 BUG_ON(ret);
1351 extent_op = (struct pending_extent_op *)(unsigned long)priv;
1352
1353 if (extent_op->type == PENDING_EXTENT_INSERT) {
1354 key.objectid = start;
1355 key.offset = end + 1 - start;
1356 key.type = BTRFS_EXTENT_ITEM_KEY;
1357 err = btrfs_insert_item(trans, extent_root, &key,
1358 &extent_item, sizeof(extent_item));
1359 BUG_ON(err);
1360
1361 clear_extent_bits(&info->extent_ins, start, end,
1362 EXTENT_LOCKED, GFP_NOFS);
1363
1364 err = insert_extent_backref(trans, extent_root, path,
1365 start, extent_op->parent,
1366 extent_root->root_key.objectid,
1367 extent_op->generation,
1368 extent_op->level);
1369 BUG_ON(err);
1370 } else if (extent_op->type == PENDING_BACKREF_UPDATE) {
1371 err = lookup_extent_backref(trans, extent_root, path,
1372 start, extent_op->orig_parent,
1373 extent_root->root_key.objectid,
1374 extent_op->orig_generation,
1375 extent_op->level, 0);
1376 BUG_ON(err);
1377
1378 clear_extent_bits(&info->extent_ins, start, end,
1379 EXTENT_LOCKED, GFP_NOFS);
1380
1381 key.objectid = start;
1382 key.offset = extent_op->parent;
1383 key.type = BTRFS_EXTENT_REF_KEY;
1384 err = btrfs_set_item_key_safe(trans, extent_root, path,
1385 &key);
1386 BUG_ON(err);
1387 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1388 struct btrfs_extent_ref);
1389 btrfs_set_ref_generation(path->nodes[0], ref,
1390 extent_op->generation);
1391 btrfs_mark_buffer_dirty(path->nodes[0]);
1392 btrfs_release_path(extent_root, path);
1393 } else {
1394 BUG_ON(1);
1395 }
1396 kfree(extent_op);
1397 }
1398 btrfs_free_path(path);
1399 return 0;
1400 }
1401
1402 static int pin_down_bytes(struct btrfs_trans_handle *trans,
1403 struct btrfs_root *root,
1404 u64 bytenr, u64 num_bytes, int is_data)
1405 {
1406 int err = 0;
1407 struct extent_buffer *buf;
1408
1409 if (is_data)
1410 goto pinit;
1411
1412 buf = btrfs_find_tree_block(root, bytenr, num_bytes);
1413 if (!buf)
1414 goto pinit;
1415
1416 /* we can reuse a block if it hasn't been written
1417 * and it is from this transaction. We can't
1418 * reuse anything from the tree log root because
1419 * it has tiny sub-transactions.
1420 */
1421 if (btrfs_buffer_uptodate(buf, 0)) {
1422 u64 header_owner = btrfs_header_owner(buf);
1423 u64 header_transid = btrfs_header_generation(buf);
1424 if (header_owner != BTRFS_TREE_LOG_OBJECTID &&
1425 header_owner != BTRFS_TREE_RELOC_OBJECTID &&
1426 header_transid == trans->transid &&
1427 !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
1428 clean_tree_block(NULL, root, buf);
1429 free_extent_buffer(buf);
1430 return 1;
1431 }
1432 }
1433 free_extent_buffer(buf);
1434 pinit:
1435 update_pinned_extents(root, bytenr, num_bytes, 1);
1436
1437 BUG_ON(err < 0);
1438 return 0;
1439 }
1440
1441 /*
1442 * remove an extent from the root, returns 0 on success
1443 */
1444 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1445 *root, u64 bytenr, u64 num_bytes, u64 parent,
1446 u64 root_objectid, u64 ref_generation,
1447 u64 owner_objectid, int pin, int mark_free)
1448 {
1449 struct btrfs_path *path;
1450 struct btrfs_key key;
1451 struct btrfs_fs_info *info = root->fs_info;
1452 struct btrfs_extent_ops *ops = info->extent_ops;
1453 struct btrfs_root *extent_root = info->extent_root;
1454 struct extent_buffer *leaf;
1455 int ret;
1456 int extent_slot = 0;
1457 int found_extent = 0;
1458 int num_to_del = 1;
1459 struct btrfs_extent_item *ei;
1460 u32 refs;
1461
1462 key.objectid = bytenr;
1463 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1464 key.offset = num_bytes;
1465
1466 path = btrfs_alloc_path();
1467 if (!path)
1468 return -ENOMEM;
1469
1470 ret = lookup_extent_backref(trans, extent_root, path,
1471 bytenr, parent, root_objectid,
1472 ref_generation, owner_objectid, 1);
1473 if (ret == 0) {
1474 struct btrfs_key found_key;
1475 extent_slot = path->slots[0];
1476 while(extent_slot > 0) {
1477 extent_slot--;
1478 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1479 extent_slot);
1480 if (found_key.objectid != bytenr)
1481 break;
1482 if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
1483 found_key.offset == num_bytes) {
1484 found_extent = 1;
1485 break;
1486 }
1487 if (path->slots[0] - extent_slot > 5)
1488 break;
1489 }
1490 if (!found_extent) {
1491 ret = remove_extent_backref(trans, extent_root, path);
1492 BUG_ON(ret);
1493 btrfs_release_path(extent_root, path);
1494 ret = btrfs_search_slot(trans, extent_root,
1495 &key, path, -1, 1);
1496 BUG_ON(ret);
1497 extent_slot = path->slots[0];
1498 }
1499 } else {
1500 btrfs_print_leaf(extent_root, path->nodes[0]);
1501 printk("Unable to find ref byte nr %llu root %llu "
1502 " gen %llu owner %llu\n",
1503 (unsigned long long)bytenr,
1504 (unsigned long long)root_objectid,
1505 (unsigned long long)ref_generation,
1506 (unsigned long long)owner_objectid);
1507 BUG_ON(1);
1508 }
1509
1510 leaf = path->nodes[0];
1511 ei = btrfs_item_ptr(leaf, extent_slot,
1512 struct btrfs_extent_item);
1513 refs = btrfs_extent_refs(leaf, ei);
1514 BUG_ON(refs == 0);
1515 refs -= 1;
1516 btrfs_set_extent_refs(leaf, ei, refs);
1517
1518 btrfs_mark_buffer_dirty(leaf);
1519
1520 if (refs == 0 && found_extent && path->slots[0] == extent_slot + 1) {
1521 struct btrfs_extent_ref *ref;
1522 ref = btrfs_item_ptr(leaf, path->slots[0],
1523 struct btrfs_extent_ref);
1524 BUG_ON(btrfs_ref_num_refs(leaf, ref) != 1);
1525 /* if the back ref and the extent are next to each other
1526 * they get deleted below in one shot
1527 */
1528 path->slots[0] = extent_slot;
1529 num_to_del = 2;
1530 } else if (found_extent) {
1531 /* otherwise delete the extent back ref */
1532 ret = remove_extent_backref(trans, extent_root, path);
1533 BUG_ON(ret);
1534 /* if refs are 0, we need to setup the path for deletion */
1535 if (refs == 0) {
1536 btrfs_release_path(extent_root, path);
1537 ret = btrfs_search_slot(trans, extent_root, &key, path,
1538 -1, 1);
1539 if (ret < 0)
1540 return ret;
1541 BUG_ON(ret);
1542 }
1543 }
1544
1545 if (refs == 0) {
1546 u64 super_used;
1547 u64 root_used;
1548
1549 if (pin) {
1550 ret = pin_down_bytes(trans, root, bytenr, num_bytes, 0);
1551 if (ret > 0)
1552 mark_free = 1;
1553 BUG_ON(ret < 0);
1554 }
1555
1556 /* block accounting for super block */
1557 super_used = btrfs_super_bytes_used(&info->super_copy);
1558 btrfs_set_super_bytes_used(&info->super_copy,
1559 super_used - num_bytes);
1560
1561 /* block accounting for root item */
1562 root_used = btrfs_root_used(&root->root_item);
1563 btrfs_set_root_used(&root->root_item,
1564 root_used - num_bytes);
1565 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
1566 num_to_del);
1567 if (ret)
1568 return ret;
1569
1570 if (ops && ops->free_extent)
1571 ops->free_extent(root, bytenr, num_bytes);
1572
1573 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
1574 mark_free);
1575 BUG_ON(ret);
1576 }
1577 btrfs_free_path(path);
1578 finish_current_insert(trans, extent_root);
1579 return ret;
1580 }
1581
1582 /*
1583 * find all the blocks marked as pending in the radix tree and remove
1584 * them from the extent map
1585 */
1586 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
1587 btrfs_root *extent_root)
1588 {
1589 int ret;
1590 int err = 0;
1591 int mark_free = 0;
1592 u64 start;
1593 u64 end;
1594 u64 priv;
1595 struct extent_io_tree *pending_del;
1596 struct extent_io_tree *extent_ins;
1597 struct pending_extent_op *extent_op;
1598
1599 extent_ins = &extent_root->fs_info->extent_ins;
1600 pending_del = &extent_root->fs_info->pending_del;
1601
1602 while(1) {
1603 ret = find_first_extent_bit(pending_del, 0, &start, &end,
1604 EXTENT_LOCKED);
1605 if (ret)
1606 break;
1607
1608 ret = get_state_private(pending_del, start, &priv);
1609 BUG_ON(ret);
1610 extent_op = (struct pending_extent_op *)(unsigned long)priv;
1611
1612 clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
1613 GFP_NOFS);
1614
1615 ret = pin_down_bytes(trans, extent_root, start,
1616 end + 1 - start, 0);
1617 mark_free = ret > 0;
1618 if (!test_range_bit(extent_ins, start, end,
1619 EXTENT_LOCKED, 0)) {
1620 free_extent:
1621 ret = __free_extent(trans, extent_root,
1622 start, end + 1 - start,
1623 extent_op->orig_parent,
1624 extent_root->root_key.objectid,
1625 extent_op->orig_generation,
1626 extent_op->level, 0, mark_free);
1627 kfree(extent_op);
1628 } else {
1629 kfree(extent_op);
1630 ret = get_state_private(extent_ins, start, &priv);
1631 BUG_ON(ret);
1632 extent_op = (struct pending_extent_op *)
1633 (unsigned long)priv;
1634
1635 clear_extent_bits(extent_ins, start, end,
1636 EXTENT_LOCKED, GFP_NOFS);
1637
1638 if (extent_op->type == PENDING_BACKREF_UPDATE)
1639 goto free_extent;
1640
1641 ret = update_block_group(trans, extent_root, start,
1642 end + 1 - start, 0, mark_free);
1643 BUG_ON(ret);
1644 kfree(extent_op);
1645 }
1646 if (ret)
1647 err = ret;
1648 }
1649 return err;
1650 }
1651
1652 /*
1653 * remove an extent from the root, returns 0 on success
1654 */
1655 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1656 *root, u64 bytenr, u64 num_bytes, u64 parent,
1657 u64 root_objectid, u64 ref_generation,
1658 u64 owner_objectid, int pin)
1659 {
1660 struct btrfs_root *extent_root = root->fs_info->extent_root;
1661 int pending_ret;
1662 int ret;
1663
1664 WARN_ON(num_bytes < root->sectorsize);
1665 if (root == extent_root) {
1666 struct pending_extent_op *extent_op;
1667
1668 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
1669 BUG_ON(!extent_op);
1670
1671 extent_op->type = PENDING_EXTENT_DELETE;
1672 extent_op->bytenr = bytenr;
1673 extent_op->num_bytes = num_bytes;
1674 extent_op->parent = parent;
1675 extent_op->orig_parent = parent;
1676 extent_op->generation = ref_generation;
1677 extent_op->orig_generation = ref_generation;
1678 extent_op->level = (int)owner_objectid;
1679
1680 set_extent_bits(&root->fs_info->pending_del,
1681 bytenr, bytenr + num_bytes - 1,
1682 EXTENT_LOCKED, GFP_NOFS);
1683 set_state_private(&root->fs_info->pending_del,
1684 bytenr, (unsigned long)extent_op);
1685 return 0;
1686 }
1687 ret = __free_extent(trans, root, bytenr, num_bytes, parent,
1688 root_objectid, ref_generation,
1689 owner_objectid, pin, pin == 0);
1690 pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
1691 return ret ? ret : pending_ret;
1692 }
1693
1694 static u64 stripe_align(struct btrfs_root *root, u64 val)
1695 {
1696 u64 mask = ((u64)root->stripesize - 1);
1697 u64 ret = (val + mask) & ~mask;
1698 return ret;
1699 }
1700
1701 /*
1702 * walks the btree of allocated extents and find a hole of a given size.
1703 * The key ins is changed to record the hole:
1704 * ins->objectid == block start
1705 * ins->flags = BTRFS_EXTENT_ITEM_KEY
1706 * ins->offset == number of blocks
1707 * Any available blocks before search_start are skipped.
1708 */
1709 static int noinline find_free_extent(struct btrfs_trans_handle *trans,
1710 struct btrfs_root *orig_root,
1711 u64 num_bytes, u64 empty_size,
1712 u64 search_start, u64 search_end,
1713 u64 hint_byte, struct btrfs_key *ins,
1714 u64 exclude_start, u64 exclude_nr,
1715 int data)
1716 {
1717 int ret;
1718 u64 orig_search_start = search_start;
1719 struct btrfs_root * root = orig_root->fs_info->extent_root;
1720 struct btrfs_fs_info *info = root->fs_info;
1721 u64 total_needed = num_bytes;
1722 struct btrfs_block_group_cache *block_group;
1723 int full_scan = 0;
1724 int wrapped = 0;
1725
1726 WARN_ON(num_bytes < root->sectorsize);
1727 btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
1728
1729 if (hint_byte) {
1730 block_group = btrfs_lookup_first_block_group(info, hint_byte);
1731 if (!block_group)
1732 hint_byte = search_start;
1733 block_group = btrfs_find_block_group(root, block_group,
1734 hint_byte, data, 1);
1735 } else {
1736 block_group = btrfs_find_block_group(root,
1737 trans->block_group,
1738 search_start, data, 1);
1739 }
1740
1741 total_needed += empty_size;
1742
1743 check_failed:
1744 if (!block_group) {
1745 block_group = btrfs_lookup_first_block_group(info,
1746 search_start);
1747 if (!block_group)
1748 block_group = btrfs_lookup_first_block_group(info,
1749 orig_search_start);
1750 }
1751 ret = find_search_start(root, &block_group, &search_start,
1752 total_needed, data);
1753 if (ret)
1754 goto error;
1755
1756 search_start = stripe_align(root, search_start);
1757 ins->objectid = search_start;
1758 ins->offset = num_bytes;
1759
1760 if (ins->objectid + num_bytes >
1761 block_group->key.objectid + block_group->key.offset) {
1762 search_start = block_group->key.objectid +
1763 block_group->key.offset;
1764 goto new_group;
1765 }
1766
1767 if (test_range_bit(&info->extent_ins, ins->objectid,
1768 ins->objectid + num_bytes -1, EXTENT_LOCKED, 0)) {
1769 search_start = ins->objectid + num_bytes;
1770 goto new_group;
1771 }
1772
1773 if (test_range_bit(&info->pinned_extents, ins->objectid,
1774 ins->objectid + num_bytes -1, EXTENT_DIRTY, 0)) {
1775 search_start = ins->objectid + num_bytes;
1776 goto new_group;
1777 }
1778
1779 if (exclude_nr > 0 && (ins->objectid + num_bytes > exclude_start &&
1780 ins->objectid < exclude_start + exclude_nr)) {
1781 search_start = exclude_start + exclude_nr;
1782 goto new_group;
1783 }
1784
1785 if (!(data & BTRFS_BLOCK_GROUP_DATA)) {
1786 block_group = btrfs_lookup_block_group(info, ins->objectid);
1787 if (block_group)
1788 trans->block_group = block_group;
1789 }
1790 ins->offset = num_bytes;
1791 return 0;
1792
1793 new_group:
1794 block_group = btrfs_lookup_first_block_group(info, search_start);
1795 if (!block_group) {
1796 search_start = orig_search_start;
1797 if (full_scan) {
1798 ret = -ENOSPC;
1799 goto error;
1800 }
1801 if (wrapped) {
1802 if (!full_scan)
1803 total_needed -= empty_size;
1804 full_scan = 1;
1805 } else
1806 wrapped = 1;
1807 }
1808 cond_resched();
1809 block_group = btrfs_find_block_group(root, block_group,
1810 search_start, data, 0);
1811 goto check_failed;
1812
1813 error:
1814 return ret;
1815 }
1816 /*
1817 * finds a free extent and does all the dirty work required for allocation
1818 * returns the key for the extent through ins, and a tree buffer for
1819 * the first block of the extent through buf.
1820 *
1821 * returns 0 if everything worked, non-zero otherwise.
1822 */
1823 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
1824 struct btrfs_root *root,
1825 u64 num_bytes, u64 parent,
1826 u64 root_objectid, u64 ref_generation,
1827 u64 owner, u64 empty_size, u64 hint_byte,
1828 u64 search_end, struct btrfs_key *ins, int data)
1829 {
1830 int ret;
1831 int pending_ret;
1832 u64 super_used, root_used;
1833 u64 search_start = 0;
1834 u64 alloc_profile;
1835 u32 sizes[2];
1836 struct btrfs_fs_info *info = root->fs_info;
1837 struct btrfs_root *extent_root = info->extent_root;
1838 struct btrfs_path *path;
1839 struct btrfs_extent_item *extent_item;
1840 struct btrfs_extent_ref *ref;
1841 struct btrfs_key keys[2];
1842
1843 if (info->extent_ops) {
1844 struct btrfs_extent_ops *ops = info->extent_ops;
1845 ret = ops->alloc_extent(root, num_bytes, hint_byte, ins);
1846 BUG_ON(ret);
1847 goto found;
1848 }
1849
1850 if (data) {
1851 alloc_profile = info->avail_data_alloc_bits &
1852 info->data_alloc_profile;
1853 data = BTRFS_BLOCK_GROUP_DATA | alloc_profile;
1854 } else if ((info->system_allocs > 0 || root == info->chunk_root) &&
1855 info->system_allocs >= 0) {
1856 alloc_profile = info->avail_system_alloc_bits &
1857 info->system_alloc_profile;
1858 data = BTRFS_BLOCK_GROUP_SYSTEM | alloc_profile;
1859 } else {
1860 alloc_profile = info->avail_metadata_alloc_bits &
1861 info->metadata_alloc_profile;
1862 data = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
1863 }
1864
1865 if (root->ref_cows) {
1866 if (!(data & BTRFS_BLOCK_GROUP_METADATA)) {
1867 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
1868 num_bytes,
1869 BTRFS_BLOCK_GROUP_METADATA);
1870 BUG_ON(ret);
1871 }
1872 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
1873 num_bytes + 2 * 1024 * 1024, data);
1874 BUG_ON(ret);
1875 }
1876
1877 WARN_ON(num_bytes < root->sectorsize);
1878 ret = find_free_extent(trans, root, num_bytes, empty_size,
1879 search_start, search_end, hint_byte, ins,
1880 trans->alloc_exclude_start,
1881 trans->alloc_exclude_nr, data);
1882 BUG_ON(ret);
1883 found:
1884 if (ret)
1885 return ret;
1886
1887 if (parent == 0)
1888 parent = ins->objectid;
1889
1890 /* block accounting for super block */
1891 super_used = btrfs_super_bytes_used(&info->super_copy);
1892 btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
1893
1894 /* block accounting for root item */
1895 root_used = btrfs_root_used(&root->root_item);
1896 btrfs_set_root_used(&root->root_item, root_used + num_bytes);
1897
1898 clear_extent_dirty(&root->fs_info->free_space_cache,
1899 ins->objectid, ins->objectid + ins->offset - 1,
1900 GFP_NOFS);
1901
1902 if (root == extent_root) {
1903 struct pending_extent_op *extent_op;
1904
1905 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
1906 BUG_ON(!extent_op);
1907
1908 extent_op->type = PENDING_EXTENT_INSERT;
1909 extent_op->bytenr = ins->objectid;
1910 extent_op->num_bytes = ins->offset;
1911 extent_op->parent = parent;
1912 extent_op->orig_parent = 0;
1913 extent_op->generation = ref_generation;
1914 extent_op->orig_generation = 0;
1915 extent_op->level = (int)owner;
1916
1917 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
1918 ins->objectid + ins->offset - 1,
1919 EXTENT_LOCKED, GFP_NOFS);
1920 set_state_private(&root->fs_info->extent_ins,
1921 ins->objectid, (unsigned long)extent_op);
1922 goto update_block;
1923 }
1924
1925 WARN_ON(trans->alloc_exclude_nr);
1926 trans->alloc_exclude_start = ins->objectid;
1927 trans->alloc_exclude_nr = ins->offset;
1928
1929 memcpy(&keys[0], ins, sizeof(*ins));
1930 keys[1].objectid = ins->objectid;
1931 keys[1].type = BTRFS_EXTENT_REF_KEY;
1932 keys[1].offset = parent;
1933 sizes[0] = sizeof(*extent_item);
1934 sizes[1] = sizeof(*ref);
1935
1936 path = btrfs_alloc_path();
1937 BUG_ON(!path);
1938
1939 ret = btrfs_insert_empty_items(trans, extent_root, path, keys,
1940 sizes, 2);
1941
1942 BUG_ON(ret);
1943 extent_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
1944 struct btrfs_extent_item);
1945 btrfs_set_extent_refs(path->nodes[0], extent_item, 1);
1946 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
1947 struct btrfs_extent_ref);
1948
1949 btrfs_set_ref_root(path->nodes[0], ref, root_objectid);
1950 btrfs_set_ref_generation(path->nodes[0], ref, ref_generation);
1951 btrfs_set_ref_objectid(path->nodes[0], ref, owner);
1952 btrfs_set_ref_num_refs(path->nodes[0], ref, 1);
1953
1954 btrfs_mark_buffer_dirty(path->nodes[0]);
1955
1956 trans->alloc_exclude_start = 0;
1957 trans->alloc_exclude_nr = 0;
1958 btrfs_free_path(path);
1959 finish_current_insert(trans, extent_root);
1960 pending_ret = del_pending_extents(trans, extent_root);
1961
1962 if (ret) {
1963 return ret;
1964 }
1965 if (pending_ret) {
1966 return pending_ret;
1967 }
1968
1969 update_block:
1970 ret = update_block_group(trans, root, ins->objectid, ins->offset, 1, 0);
1971 if (ret) {
1972 printk("update block group failed for %llu %llu\n",
1973 (unsigned long long)ins->objectid,
1974 (unsigned long long)ins->offset);
1975 BUG();
1976 }
1977 return 0;
1978 }
1979
1980 /*
1981 * helper function to allocate a block for a given tree
1982 * returns the tree buffer or NULL.
1983 */
1984 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1985 struct btrfs_root *root,
1986 u32 blocksize, u64 parent,
1987 u64 root_objectid,
1988 u64 ref_generation,
1989 int level,
1990 u64 hint,
1991 u64 empty_size)
1992 {
1993 struct btrfs_key ins;
1994 int ret;
1995 struct extent_buffer *buf;
1996
1997 ret = btrfs_alloc_extent(trans, root, blocksize, parent,
1998 root_objectid, ref_generation,
1999 level, empty_size, hint,
2000 (u64)-1, &ins, 0);
2001 if (ret) {
2002 BUG_ON(ret > 0);
2003 return ERR_PTR(ret);
2004 }
2005 buf = btrfs_find_create_tree_block(root, ins.objectid, blocksize);
2006 if (!buf) {
2007 if (parent == 0)
2008 parent = ins.objectid;
2009 btrfs_free_extent(trans, root, ins.objectid, blocksize,
2010 parent, root->root_key.objectid,
2011 ref_generation, level, 0);
2012 BUG_ON(1);
2013 return ERR_PTR(-ENOMEM);
2014 }
2015 btrfs_set_buffer_uptodate(buf);
2016 trans->blocks_used++;
2017 return buf;
2018 }
2019
2020 static int noinline drop_leaf_ref(struct btrfs_trans_handle *trans,
2021 struct btrfs_root *root,
2022 struct extent_buffer *leaf)
2023 {
2024 u64 leaf_owner;
2025 u64 leaf_generation;
2026 struct btrfs_key key;
2027 struct btrfs_file_extent_item *fi;
2028 int i;
2029 int nritems;
2030 int ret;
2031
2032 BUG_ON(!btrfs_is_leaf(leaf));
2033 nritems = btrfs_header_nritems(leaf);
2034 leaf_owner = btrfs_header_owner(leaf);
2035 leaf_generation = btrfs_header_generation(leaf);
2036
2037 for (i = 0; i < nritems; i++) {
2038 u64 disk_bytenr;
2039
2040 btrfs_item_key_to_cpu(leaf, &key, i);
2041 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2042 continue;
2043 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
2044 if (btrfs_file_extent_type(leaf, fi) ==
2045 BTRFS_FILE_EXTENT_INLINE)
2046 continue;
2047 /*
2048 * FIXME make sure to insert a trans record that
2049 * repeats the snapshot del on crash
2050 */
2051 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
2052 if (disk_bytenr == 0)
2053 continue;
2054 ret = btrfs_free_extent(trans, root, disk_bytenr,
2055 btrfs_file_extent_disk_num_bytes(leaf, fi),
2056 leaf->start, leaf_owner, leaf_generation,
2057 key.objectid, 0);
2058 BUG_ON(ret);
2059 }
2060 return 0;
2061 }
2062
2063 static void noinline reada_walk_down(struct btrfs_root *root,
2064 struct extent_buffer *node,
2065 int slot)
2066 {
2067 u64 bytenr;
2068 u64 last = 0;
2069 u32 nritems;
2070 u32 refs;
2071 u32 blocksize;
2072 int ret;
2073 int i;
2074 int level;
2075 int skipped = 0;
2076
2077 nritems = btrfs_header_nritems(node);
2078 level = btrfs_header_level(node);
2079 if (level)
2080 return;
2081
2082 for (i = slot; i < nritems && skipped < 32; i++) {
2083 bytenr = btrfs_node_blockptr(node, i);
2084 if (last && ((bytenr > last && bytenr - last > 32 * 1024) ||
2085 (last > bytenr && last - bytenr > 32 * 1024))) {
2086 skipped++;
2087 continue;
2088 }
2089 blocksize = btrfs_level_size(root, level - 1);
2090 if (i != slot) {
2091 ret = lookup_extent_ref(NULL, root, bytenr,
2092 blocksize, &refs);
2093 BUG_ON(ret);
2094 if (refs != 1) {
2095 skipped++;
2096 continue;
2097 }
2098 }
2099 mutex_unlock(&root->fs_info->fs_mutex);
2100 ret = readahead_tree_block(root, bytenr, blocksize,
2101 btrfs_node_ptr_generation(node, i));
2102 last = bytenr + blocksize;
2103 cond_resched();
2104 mutex_lock(&root->fs_info->fs_mutex);
2105 if (ret)
2106 break;
2107 }
2108 }
2109
2110 /*
2111 * helper function for drop_snapshot, this walks down the tree dropping ref
2112 * counts as it goes.
2113 */
2114 static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
2115 struct btrfs_root *root,
2116 struct btrfs_path *path, int *level)
2117 {
2118 u64 root_owner;
2119 u64 root_gen;
2120 u64 bytenr;
2121 u64 ptr_gen;
2122 struct extent_buffer *next;
2123 struct extent_buffer *cur;
2124 struct extent_buffer *parent;
2125 u32 blocksize;
2126 int ret;
2127 u32 refs;
2128
2129 WARN_ON(*level < 0);
2130 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2131 ret = lookup_extent_ref(trans, root,
2132 path->nodes[*level]->start,
2133 path->nodes[*level]->len, &refs);
2134 BUG_ON(ret);
2135 if (refs > 1)
2136 goto out;
2137
2138 /*
2139 * walk down to the last node level and free all the leaves
2140 */
2141 while(*level >= 0) {
2142 WARN_ON(*level < 0);
2143 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2144 cur = path->nodes[*level];
2145
2146 if (btrfs_header_level(cur) != *level)
2147 WARN_ON(1);
2148
2149 if (path->slots[*level] >=
2150 btrfs_header_nritems(cur))
2151 break;
2152 if (*level == 0) {
2153 ret = drop_leaf_ref(trans, root, cur);
2154 BUG_ON(ret);
2155 break;
2156 }
2157 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
2158 ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
2159 blocksize = btrfs_level_size(root, *level - 1);
2160 ret = lookup_extent_ref(trans, root, bytenr, blocksize, &refs);
2161 BUG_ON(ret);
2162 if (refs != 1) {
2163 parent = path->nodes[*level];
2164 root_owner = btrfs_header_owner(parent);
2165 root_gen = btrfs_header_generation(parent);
2166 path->slots[*level]++;
2167 ret = btrfs_free_extent(trans, root, bytenr, blocksize,
2168 parent->start, root_owner,
2169 root_gen, *level - 1, 1);
2170 BUG_ON(ret);
2171 continue;
2172 }
2173 next = btrfs_find_tree_block(root, bytenr, blocksize);
2174 if (!next || !btrfs_buffer_uptodate(next, ptr_gen)) {
2175 free_extent_buffer(next);
2176 reada_walk_down(root, cur, path->slots[*level]);
2177 mutex_unlock(&root->fs_info->fs_mutex);
2178 next = read_tree_block(root, bytenr, blocksize,
2179 ptr_gen);
2180 mutex_lock(&root->fs_info->fs_mutex);
2181 }
2182 WARN_ON(*level <= 0);
2183 if (path->nodes[*level-1])
2184 free_extent_buffer(path->nodes[*level-1]);
2185 path->nodes[*level-1] = next;
2186 *level = btrfs_header_level(next);
2187 path->slots[*level] = 0;
2188 }
2189 out:
2190 WARN_ON(*level < 0);
2191 WARN_ON(*level >= BTRFS_MAX_LEVEL);
2192
2193 if (path->nodes[*level] == root->node) {
2194 root_owner = root->root_key.objectid;
2195 parent = path->nodes[*level];
2196 } else {
2197 parent = path->nodes[*level + 1];
2198 root_owner = btrfs_header_owner(parent);
2199 }
2200
2201 root_gen = btrfs_header_generation(parent);
2202 ret = btrfs_free_extent(trans, root, path->nodes[*level]->start,
2203 path->nodes[*level]->len, parent->start,
2204 root_owner, root_gen, *level, 1);
2205 free_extent_buffer(path->nodes[*level]);
2206 path->nodes[*level] = NULL;
2207 *level += 1;
2208 BUG_ON(ret);
2209 return 0;
2210 }
2211
2212 /*
2213 * helper for dropping snapshots. This walks back up the tree in the path
2214 * to find the first node higher up where we haven't yet gone through
2215 * all the slots
2216 */
2217 static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
2218 struct btrfs_root *root,
2219 struct btrfs_path *path, int *level)
2220 {
2221 u64 root_owner;
2222 u64 root_gen;
2223 struct btrfs_root_item *root_item = &root->root_item;
2224 int i;
2225 int slot;
2226 int ret;
2227
2228 for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
2229 slot = path->slots[i];
2230 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
2231 struct extent_buffer *node;
2232 struct btrfs_disk_key disk_key;
2233 node = path->nodes[i];
2234 path->slots[i]++;
2235 *level = i;
2236 WARN_ON(*level == 0);
2237 btrfs_node_key(node, &disk_key, path->slots[i]);
2238 memcpy(&root_item->drop_progress,
2239 &disk_key, sizeof(disk_key));
2240 root_item->drop_level = i;
2241 return 0;
2242 } else {
2243 struct extent_buffer *parent;
2244 if (path->nodes[*level] == root->node)
2245 parent = path->nodes[*level];
2246 else
2247 parent = path->nodes[*level + 1];
2248
2249 root_owner = btrfs_header_owner(parent);
2250 root_gen = btrfs_header_generation(parent);
2251 ret = btrfs_free_extent(trans, root,
2252 path->nodes[*level]->start,
2253 path->nodes[*level]->len,
2254 parent->start, root_owner,
2255 root_gen, *level, 1);
2256 BUG_ON(ret);
2257 free_extent_buffer(path->nodes[*level]);
2258 path->nodes[*level] = NULL;
2259 *level = i + 1;
2260 }
2261 }
2262 return 1;
2263 }
2264
2265 /*
2266 * drop the reference count on the tree rooted at 'snap'. This traverses
2267 * the tree freeing any blocks that have a ref count of zero after being
2268 * decremented.
2269 */
2270 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
2271 *root)
2272 {
2273 int ret = 0;
2274 int wret;
2275 int level;
2276 struct btrfs_path *path;
2277 int i;
2278 int orig_level;
2279 struct btrfs_root_item *root_item = &root->root_item;
2280
2281 path = btrfs_alloc_path();
2282 BUG_ON(!path);
2283
2284 level = btrfs_header_level(root->node);
2285 orig_level = level;
2286 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2287 path->nodes[level] = root->node;
2288 extent_buffer_get(root->node);
2289 path->slots[level] = 0;
2290 } else {
2291 struct btrfs_key key;
2292 struct btrfs_disk_key found_key;
2293 struct extent_buffer *node;
2294
2295 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2296 level = root_item->drop_level;
2297 path->lowest_level = level;
2298 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2299 if (wret < 0) {
2300 ret = wret;
2301 goto out;
2302 }
2303 node = path->nodes[level];
2304 btrfs_node_key(node, &found_key, path->slots[level]);
2305 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
2306 sizeof(found_key)));
2307 }
2308 while(1) {
2309 wret = walk_down_tree(trans, root, path, &level);
2310 if (wret < 0)
2311 ret = wret;
2312 if (wret != 0)
2313 break;
2314
2315 wret = walk_up_tree(trans, root, path, &level);
2316 if (wret < 0)
2317 ret = wret;
2318 if (wret != 0)
2319 break;
2320 /*
2321 ret = -EAGAIN;
2322 break;
2323 */
2324 }
2325 for (i = 0; i <= orig_level; i++) {
2326 if (path->nodes[i]) {
2327 free_extent_buffer(path->nodes[i]);
2328 path->nodes[i] = NULL;
2329 }
2330 }
2331 out:
2332 btrfs_free_path(path);
2333 return ret;
2334 }
2335
2336 int btrfs_free_block_groups(struct btrfs_fs_info *info)
2337 {
2338 u64 start;
2339 u64 end;
2340 u64 ptr;
2341 int ret;
2342 while(1) {
2343 ret = find_first_extent_bit(&info->block_group_cache, 0,
2344 &start, &end, (unsigned int)-1);
2345 if (ret)
2346 break;
2347 ret = get_state_private(&info->block_group_cache, start, &ptr);
2348 if (!ret)
2349 kfree((void *)(unsigned long)ptr);
2350 clear_extent_bits(&info->block_group_cache, start,
2351 end, (unsigned int)-1, GFP_NOFS);
2352 }
2353 while(1) {
2354 ret = find_first_extent_bit(&info->free_space_cache, 0,
2355 &start, &end, EXTENT_DIRTY);
2356 if (ret)
2357 break;
2358 clear_extent_dirty(&info->free_space_cache, start,
2359 end, GFP_NOFS);
2360 }
2361 return 0;
2362 }
2363
2364 int find_first_block_group(struct btrfs_root *root, struct btrfs_path *path,
2365 struct btrfs_key *key)
2366 {
2367 int ret;
2368 struct btrfs_key found_key;
2369 struct extent_buffer *leaf;
2370 int slot;
2371
2372 ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
2373 if (ret < 0)
2374 return ret;
2375 while(1) {
2376 slot = path->slots[0];
2377 leaf = path->nodes[0];
2378 if (slot >= btrfs_header_nritems(leaf)) {
2379 ret = btrfs_next_leaf(root, path);
2380 if (ret == 0)
2381 continue;
2382 if (ret < 0)
2383 goto error;
2384 break;
2385 }
2386 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2387
2388 if (found_key.objectid >= key->objectid &&
2389 found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY)
2390 return 0;
2391 path->slots[0]++;
2392 }
2393 ret = -ENOENT;
2394 error:
2395 return ret;
2396 }
2397
2398 int btrfs_read_block_groups(struct btrfs_root *root)
2399 {
2400 struct btrfs_path *path;
2401 int ret;
2402 int bit;
2403 struct btrfs_block_group_cache *cache;
2404 struct btrfs_fs_info *info = root->fs_info;
2405 struct btrfs_space_info *space_info;
2406 struct extent_io_tree *block_group_cache;
2407 struct btrfs_key key;
2408 struct btrfs_key found_key;
2409 struct extent_buffer *leaf;
2410
2411 block_group_cache = &info->block_group_cache;
2412
2413 root = info->extent_root;
2414 key.objectid = 0;
2415 key.offset = 0;
2416 btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2417 path = btrfs_alloc_path();
2418 if (!path)
2419 return -ENOMEM;
2420
2421 while(1) {
2422 ret = find_first_block_group(root, path, &key);
2423 if (ret > 0) {
2424 ret = 0;
2425 goto error;
2426 }
2427 if (ret != 0) {
2428 goto error;
2429 }
2430 leaf = path->nodes[0];
2431 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2432 cache = kzalloc(sizeof(*cache), GFP_NOFS);
2433 if (!cache) {
2434 ret = -ENOMEM;
2435 break;
2436 }
2437
2438 read_extent_buffer(leaf, &cache->item,
2439 btrfs_item_ptr_offset(leaf, path->slots[0]),
2440 sizeof(cache->item));
2441 memcpy(&cache->key, &found_key, sizeof(found_key));
2442 cache->cached = 0;
2443 cache->pinned = 0;
2444 key.objectid = found_key.objectid + found_key.offset;
2445 btrfs_release_path(root, path);
2446 cache->flags = btrfs_block_group_flags(&cache->item);
2447 bit = 0;
2448 if (cache->flags & BTRFS_BLOCK_GROUP_DATA) {
2449 bit = BLOCK_GROUP_DATA;
2450 } else if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
2451 bit = BLOCK_GROUP_SYSTEM;
2452 } else if (cache->flags & BTRFS_BLOCK_GROUP_METADATA) {
2453 bit = BLOCK_GROUP_METADATA;
2454 }
2455 set_avail_alloc_bits(info, cache->flags);
2456 if (btrfs_chunk_readonly(root, cache->key.objectid))
2457 cache->ro = 1;
2458
2459 ret = update_space_info(info, cache->flags, found_key.offset,
2460 btrfs_block_group_used(&cache->item),
2461 &space_info);
2462 BUG_ON(ret);
2463 cache->space_info = space_info;
2464
2465 /* use EXTENT_LOCKED to prevent merging */
2466 set_extent_bits(block_group_cache, found_key.objectid,
2467 found_key.objectid + found_key.offset - 1,
2468 bit | EXTENT_LOCKED, GFP_NOFS);
2469 set_state_private(block_group_cache, found_key.objectid,
2470 (unsigned long)cache);
2471 }
2472 ret = 0;
2473 error:
2474 btrfs_free_path(path);
2475 return ret;
2476 }
2477
2478 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
2479 struct btrfs_root *root, u64 bytes_used,
2480 u64 type, u64 chunk_objectid, u64 chunk_offset,
2481 u64 size)
2482 {
2483 int ret;
2484 int bit = 0;
2485 struct btrfs_root *extent_root;
2486 struct btrfs_block_group_cache *cache;
2487 struct extent_io_tree *block_group_cache;
2488
2489 extent_root = root->fs_info->extent_root;
2490 block_group_cache = &root->fs_info->block_group_cache;
2491
2492 cache = kzalloc(sizeof(*cache), GFP_NOFS);
2493 BUG_ON(!cache);
2494 cache->key.objectid = chunk_offset;
2495 cache->key.offset = size;
2496
2497 btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2498 btrfs_set_block_group_used(&cache->item, bytes_used);
2499 btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
2500 cache->flags = type;
2501 btrfs_set_block_group_flags(&cache->item, type);
2502
2503 ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
2504 &cache->space_info);
2505 BUG_ON(ret);
2506
2507 bit = block_group_state_bits(type);
2508 set_extent_bits(block_group_cache, chunk_offset,
2509 chunk_offset + size - 1,
2510 bit | EXTENT_LOCKED, GFP_NOFS);
2511
2512 set_state_private(block_group_cache, chunk_offset,
2513 (unsigned long)cache);
2514 ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
2515 sizeof(cache->item));
2516 BUG_ON(ret);
2517
2518 finish_current_insert(trans, extent_root);
2519 ret = del_pending_extents(trans, extent_root);
2520 BUG_ON(ret);
2521 set_avail_alloc_bits(extent_root->fs_info, type);
2522 return 0;
2523 }
2524
2525 /*
2526 * This is for converter use only.
2527 *
2528 * In that case, we don't know where are free blocks located.
2529 * Therefore all block group cache entries must be setup properly
2530 * before doing any block allocation.
2531 */
2532 int btrfs_make_block_groups(struct btrfs_trans_handle *trans,
2533 struct btrfs_root *root)
2534 {
2535 u64 total_bytes;
2536 u64 cur_start;
2537 u64 group_type;
2538 u64 group_size;
2539 u64 group_align;
2540 u64 total_data = 0;
2541 u64 total_metadata = 0;
2542 u64 chunk_objectid;
2543 int ret;
2544 int bit;
2545 struct btrfs_root *extent_root;
2546 struct btrfs_block_group_cache *cache;
2547 struct extent_io_tree *block_group_cache;
2548
2549 extent_root = root->fs_info->extent_root;
2550 block_group_cache = &root->fs_info->block_group_cache;
2551 chunk_objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2552 total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
2553 group_align = 64 * root->sectorsize;
2554
2555 cur_start = 0;
2556 while (cur_start < total_bytes) {
2557 group_size = total_bytes / 12;
2558 group_size = min_t(u64, group_size, total_bytes - cur_start);
2559 if (cur_start == 0) {
2560 bit = BLOCK_GROUP_SYSTEM;
2561 group_type = BTRFS_BLOCK_GROUP_SYSTEM;
2562 group_size /= 4;
2563 group_size &= ~(group_align - 1);
2564 group_size = max_t(u64, group_size, 32 * 1024 * 1024);
2565 group_size = min_t(u64, group_size, 128 * 1024 * 1024);
2566 } else {
2567 group_size &= ~(group_align - 1);
2568 if (total_data >= total_metadata * 2) {
2569 group_type = BTRFS_BLOCK_GROUP_METADATA;
2570 group_size = min_t(u64, group_size,
2571 1ULL * 1024 * 1024 * 1024);
2572 total_metadata += group_size;
2573 } else {
2574 group_type = BTRFS_BLOCK_GROUP_DATA;
2575 group_size = min_t(u64, group_size,
2576 5ULL * 1024 * 1024 * 1024);
2577 total_data += group_size;
2578 }
2579 if ((total_bytes - cur_start) * 4 < group_size * 5)
2580 group_size = total_bytes - cur_start;
2581 }
2582
2583 cache = kzalloc(sizeof(*cache), GFP_NOFS);
2584 BUG_ON(!cache);
2585
2586 cache->key.objectid = cur_start;
2587 cache->key.offset = group_size;
2588 btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2589
2590 btrfs_set_block_group_used(&cache->item, 0);
2591 btrfs_set_block_group_chunk_objectid(&cache->item,
2592 chunk_objectid);
2593 btrfs_set_block_group_flags(&cache->item, group_type);
2594
2595 cache->flags = group_type;
2596
2597 ret = update_space_info(root->fs_info, group_type, group_size,
2598 0, &cache->space_info);
2599 BUG_ON(ret);
2600 set_avail_alloc_bits(extent_root->fs_info, group_type);
2601
2602 set_extent_bits(block_group_cache, cur_start,
2603 cur_start + group_size - 1,
2604 bit | EXTENT_LOCKED, GFP_NOFS);
2605 set_state_private(block_group_cache, cur_start,
2606 (unsigned long)cache);
2607 cur_start += group_size;
2608 }
2609 /* then insert all the items */
2610 cur_start = 0;
2611 while(cur_start < total_bytes) {
2612 cache = btrfs_lookup_block_group(root->fs_info, cur_start);
2613 BUG_ON(!cache);
2614
2615 ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
2616 sizeof(cache->item));
2617 BUG_ON(ret);
2618
2619 finish_current_insert(trans, extent_root);
2620 ret = del_pending_extents(trans, extent_root);
2621 BUG_ON(ret);
2622
2623 cur_start = cache->key.objectid + cache->key.offset;
2624 }
2625 return 0;
2626 }
2627
2628 int btrfs_update_block_group(struct btrfs_trans_handle *trans,
2629 struct btrfs_root *root,
2630 u64 bytenr, u64 num_bytes, int alloc,
2631 int mark_free)
2632 {
2633 return update_block_group(trans, root, bytenr, num_bytes,
2634 alloc, mark_free);
2635 }
Btrfs-progs-unstable mirror