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Add support for single single duplication of metadata
[btrfs-progs-unstable.git] / extent-tree.c
blobba4460044c3538231e179b267bd3438b2a471ca2
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 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
37 btrfs_root *extent_root);
38 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
39 btrfs_root *extent_root);
40 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
41 struct btrfs_root *root, u64 bytes_used,
42 u64 type, u64 chunk_tree, u64 chunk_objectid,
43 u64 size);
44
45 static int cache_block_group(struct btrfs_root *root,
46 struct btrfs_block_group_cache *block_group)
47 {
48 struct btrfs_path *path;
49 int ret;
50 struct btrfs_key key;
51 struct extent_buffer *leaf;
52 struct extent_io_tree *free_space_cache;
53 int slot;
54 u64 last = 0;
55 u64 hole_size;
56 u64 first_free;
57 int found = 0;
58
59 if (!block_group)
60 return 0;
61
62 root = root->fs_info->extent_root;
63 free_space_cache = &root->fs_info->free_space_cache;
64
65 if (block_group->cached)
66 return 0;
67
68 path = btrfs_alloc_path();
69 if (!path)
70 return -ENOMEM;
71
72 path->reada = 2;
73 first_free = block_group->key.objectid;
74 key.objectid = block_group->key.objectid;
75 key.offset = 0;
76 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
77 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
78 if (ret < 0)
79 return ret;
80 ret = btrfs_previous_item(root, path, 0, BTRFS_EXTENT_ITEM_KEY);
81 if (ret < 0)
82 return ret;
83 if (ret == 0) {
84 leaf = path->nodes[0];
85 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
86 if (key.objectid + key.offset > first_free)
87 first_free = key.objectid + key.offset;
88 }
89 while(1) {
90 leaf = path->nodes[0];
91 slot = path->slots[0];
92 if (slot >= btrfs_header_nritems(leaf)) {
93 ret = btrfs_next_leaf(root, path);
94 if (ret < 0)
95 goto err;
96 if (ret == 0) {
97 continue;
98 } else {
99 break;
100 }
101 }
102 btrfs_item_key_to_cpu(leaf, &key, slot);
103 if (key.objectid < block_group->key.objectid) {
104 goto next;
105 }
106 if (key.objectid >= block_group->key.objectid +
107 block_group->key.offset) {
108 break;
109 }
110
111 if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
112 if (!found) {
113 last = first_free;
114 found = 1;
115 }
116 if (key.objectid > last) {
117 hole_size = key.objectid - last;
118 set_extent_dirty(free_space_cache, last,
119 last + hole_size - 1,
120 GFP_NOFS);
121 }
122 last = key.objectid + key.offset;
123 }
124 next:
125 path->slots[0]++;
126 }
127
128 if (!found)
129 last = first_free;
130 if (block_group->key.objectid +
131 block_group->key.offset > last) {
132 hole_size = block_group->key.objectid +
133 block_group->key.offset - last;
134 set_extent_dirty(free_space_cache, last,
135 last + hole_size - 1, GFP_NOFS);
136 }
137 block_group->cached = 1;
138 err:
139 btrfs_free_path(path);
140 return 0;
141 }
142
143 struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
144 btrfs_fs_info *info,
145 u64 bytenr)
146 {
147 struct extent_io_tree *block_group_cache;
148 struct btrfs_block_group_cache *block_group = NULL;
149 u64 ptr;
150 u64 start;
151 u64 end;
152 int ret;
153
154 block_group_cache = &info->block_group_cache;
155 ret = find_first_extent_bit(block_group_cache,
156 bytenr, &start, &end,
157 BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA |
158 BLOCK_GROUP_SYSTEM);
159 if (ret) {
160 return NULL;
161 }
162 ret = get_state_private(block_group_cache, start, &ptr);
163 if (ret)
164 return NULL;
165
166 block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
167 if (block_group->key.objectid <= bytenr && bytenr <
168 block_group->key.objectid + block_group->key.offset)
169 return block_group;
170 return NULL;
171 }
172
173 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
174 {
175 return (cache->flags & bits);
176 }
177
178 static int noinline find_search_start(struct btrfs_root *root,
179 struct btrfs_block_group_cache **cache_ret,
180 u64 *start_ret, int num, int data)
181 {
182 int ret;
183 struct btrfs_block_group_cache *cache = *cache_ret;
184 u64 last;
185 u64 start = 0;
186 u64 end = 0;
187 u64 cache_miss = 0;
188 u64 search_start = *start_ret;
189 int wrapped = 0;
190
191 if (!cache) {
192 goto out;
193 }
194 again:
195 ret = cache_block_group(root, cache);
196 if (ret)
197 goto out;
198
199 last = max(search_start, cache->key.objectid);
200 if (!block_group_bits(cache, data)) {
201 goto new_group;
202 }
203
204 while(1) {
205 ret = find_first_extent_bit(&root->fs_info->free_space_cache,
206 last, &start, &end, EXTENT_DIRTY);
207 if (ret) {
208 if (!cache_miss)
209 cache_miss = last;
210 goto new_group;
211 }
212
213 start = max(last, start);
214 last = end + 1;
215 if (last - start < num) {
216 if (last == cache->key.objectid + cache->key.offset)
217 cache_miss = start;
218 continue;
219 }
220 if (start + num > cache->key.objectid + cache->key.offset)
221 goto new_group;
222 *start_ret = start;
223 return 0;
224 }
225 out:
226 cache = btrfs_lookup_block_group(root->fs_info, search_start);
227 if (!cache) {
228 printk("Unable to find block group for %llu\n",
229 (unsigned long long)search_start);
230 WARN_ON(1);
231 }
232 return -ENOSPC;
233
234 new_group:
235 last = cache->key.objectid + cache->key.offset;
236 wrapped:
237 cache = btrfs_lookup_block_group(root->fs_info, last);
238 if (!cache) {
239 no_cache:
240 if (!wrapped) {
241 wrapped = 1;
242 last = search_start;
243 goto wrapped;
244 }
245 goto out;
246 }
247 if (cache_miss && !cache->cached) {
248 cache_block_group(root, cache);
249 last = cache_miss;
250 cache = btrfs_lookup_block_group(root->fs_info, last);
251 }
252 cache = btrfs_find_block_group(root, cache, last, data, 0);
253 if (!cache)
254 goto no_cache;
255 *cache_ret = cache;
256 cache_miss = 0;
257 goto again;
258 }
259
260 static u64 div_factor(u64 num, int factor)
261 {
262 if (factor == 10)
263 return num;
264 num *= factor;
265 num /= 10;
266 return num;
267 }
268
269 static int block_group_state_bits(u64 flags)
270 {
271 int bits = 0;
272 if (flags & BTRFS_BLOCK_GROUP_DATA)
273 bits |= BLOCK_GROUP_DATA;
274 if (flags & BTRFS_BLOCK_GROUP_METADATA)
275 bits |= BLOCK_GROUP_METADATA;
276 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
277 bits |= BLOCK_GROUP_SYSTEM;
278 return bits;
279 }
280
281 struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
282 struct btrfs_block_group_cache
283 *hint, u64 search_start,
284 int data, int owner)
285 {
286 struct btrfs_block_group_cache *cache;
287 struct extent_io_tree *block_group_cache;
288 struct btrfs_block_group_cache *found_group = NULL;
289 struct btrfs_fs_info *info = root->fs_info;
290 u64 used;
291 u64 last = 0;
292 u64 hint_last;
293 u64 start;
294 u64 end;
295 u64 free_check;
296 u64 ptr;
297 int bit;
298 int ret;
299 int full_search = 0;
300 int factor = 8;
301
302 block_group_cache = &info->block_group_cache;
303
304 if (!owner)
305 factor = 8;
306
307 bit = block_group_state_bits(data);
308
309 if (search_start) {
310 struct btrfs_block_group_cache *shint;
311 shint = btrfs_lookup_block_group(info, search_start);
312 if (shint && block_group_bits(shint, data)) {
313 used = btrfs_block_group_used(&shint->item);
314 if (used + shint->pinned <
315 div_factor(shint->key.offset, factor)) {
316 return shint;
317 }
318 }
319 }
320 if (hint && block_group_bits(hint, data)) {
321 used = btrfs_block_group_used(&hint->item);
322 if (used + hint->pinned <
323 div_factor(hint->key.offset, factor)) {
324 return hint;
325 }
326 last = hint->key.objectid + hint->key.offset;
327 hint_last = last;
328 } else {
329 if (hint)
330 hint_last = max(hint->key.objectid, search_start);
331 else
332 hint_last = search_start;
333
334 last = hint_last;
335 }
336 again:
337 while(1) {
338 ret = find_first_extent_bit(block_group_cache, last,
339 &start, &end, bit);
340 if (ret)
341 break;
342
343 ret = get_state_private(block_group_cache, start, &ptr);
344 if (ret)
345 break;
346
347 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
348 last = cache->key.objectid + cache->key.offset;
349 used = btrfs_block_group_used(&cache->item);
350
351 if (full_search)
352 free_check = cache->key.offset;
353 else
354 free_check = div_factor(cache->key.offset, factor);
355
356 if (used + cache->pinned < free_check) {
357 found_group = cache;
358 goto found;
359 }
360 cond_resched();
361 }
362 if (!full_search) {
363 last = search_start;
364 full_search = 1;
365 goto again;
366 }
367 found:
368 return found_group;
369 }
370
371 static u64 hash_extent_ref(u64 root_objectid, u64 ref_generation,
372 u64 owner, u64 owner_offset)
373 {
374 u32 high_crc = ~(u32)0;
375 u32 low_crc = ~(u32)0;
376 __le64 lenum;
377
378 lenum = cpu_to_le64(root_objectid);
379 high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
380 lenum = cpu_to_le64(ref_generation);
381 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
382 if (owner >= BTRFS_FIRST_FREE_OBJECTID) {
383 lenum = cpu_to_le64(owner);
384 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
385 lenum = cpu_to_le64(owner_offset);
386 low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
387 }
388 return ((u64)high_crc << 32) | (u64)low_crc;
389 }
390
391 static int match_extent_ref(struct extent_buffer *leaf,
392 struct btrfs_extent_ref *disk_ref,
393 struct btrfs_extent_ref *cpu_ref)
394 {
395 int ret;
396 int len;
397
398 if (cpu_ref->objectid)
399 len = sizeof(*cpu_ref);
400 else
401 len = 2 * sizeof(u64);
402 ret = memcmp_extent_buffer(leaf, cpu_ref, (unsigned long)disk_ref,
403 len);
404 return ret == 0;
405 }
406
407 static int noinline lookup_extent_backref(struct btrfs_trans_handle *trans,
408 struct btrfs_root *root,
409 struct btrfs_path *path, u64 bytenr,
410 u64 root_objectid,
411 u64 ref_generation, u64 owner,
412 u64 owner_offset, int del)
413 {
414 u64 hash;
415 struct btrfs_key key;
416 struct btrfs_key found_key;
417 struct btrfs_extent_ref ref;
418 struct extent_buffer *leaf;
419 struct btrfs_extent_ref *disk_ref;
420 int ret;
421 int ret2;
422
423 btrfs_set_stack_ref_root(&ref, root_objectid);
424 btrfs_set_stack_ref_generation(&ref, ref_generation);
425 btrfs_set_stack_ref_objectid(&ref, owner);
426 btrfs_set_stack_ref_offset(&ref, owner_offset);
427
428 hash = hash_extent_ref(root_objectid, ref_generation, owner,
429 owner_offset);
430 key.offset = hash;
431 key.objectid = bytenr;
432 key.type = BTRFS_EXTENT_REF_KEY;
433
434 while (1) {
435 ret = btrfs_search_slot(trans, root, &key, path,
436 del ? -1 : 0, del);
437 if (ret < 0)
438 goto out;
439 leaf = path->nodes[0];
440 if (ret != 0) {
441 u32 nritems = btrfs_header_nritems(leaf);
442 if (path->slots[0] >= nritems) {
443 ret2 = btrfs_next_leaf(root, path);
444 if (ret2)
445 goto out;
446 leaf = path->nodes[0];
447 }
448 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
449 if (found_key.objectid != bytenr ||
450 found_key.type != BTRFS_EXTENT_REF_KEY)
451 goto out;
452 key.offset = found_key.offset;
453 if (del) {
454 btrfs_release_path(root, path);
455 continue;
456 }
457 }
458 disk_ref = btrfs_item_ptr(path->nodes[0],
459 path->slots[0],
460 struct btrfs_extent_ref);
461 if (match_extent_ref(path->nodes[0], disk_ref, &ref)) {
462 ret = 0;
463 goto out;
464 }
465 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
466 key.offset = found_key.offset + 1;
467 btrfs_release_path(root, path);
468 }
469 out:
470 return ret;
471 }
472
473 /*
474 * Back reference rules. Back refs have three main goals:
475 *
476 * 1) differentiate between all holders of references to an extent so that
477 * when a reference is dropped we can make sure it was a valid reference
478 * before freeing the extent.
479 *
480 * 2) Provide enough information to quickly find the holders of an extent
481 * if we notice a given block is corrupted or bad.
482 *
483 * 3) Make it easy to migrate blocks for FS shrinking or storage pool
484 * maintenance. This is actually the same as #2, but with a slightly
485 * different use case.
486 *
487 * File extents can be referenced by:
488 *
489 * - multiple snapshots, subvolumes, or different generations in one subvol
490 * - different files inside a single subvolume (in theory, not implemented yet)
491 * - different offsets inside a file (bookend extents in file.c)
492 *
493 * The extent ref structure has fields for:
494 *
495 * - Objectid of the subvolume root
496 * - Generation number of the tree holding the reference
497 * - objectid of the file holding the reference
498 * - offset in the file corresponding to the key holding the reference
499 *
500 * When a file extent is allocated the fields are filled in:
501 * (root_key.objectid, trans->transid, inode objectid, offset in file)
502 *
503 * When a leaf is cow'd new references are added for every file extent found
504 * in the leaf. It looks the same as the create case, but trans->transid
505 * will be different when the block is cow'd.
506 *
507 * (root_key.objectid, trans->transid, inode objectid, offset in file)
508 *
509 * When a file extent is removed either during snapshot deletion or file
510 * truncation, the corresponding back reference is found
511 * by searching for:
512 *
513 * (btrfs_header_owner(leaf), btrfs_header_generation(leaf),
514 * inode objectid, offset in file)
515 *
516 * Btree extents can be referenced by:
517 *
518 * - Different subvolumes
519 * - Different generations of the same subvolume
520 *
521 * Storing sufficient information for a full reverse mapping of a btree
522 * block would require storing the lowest key of the block in the backref,
523 * and it would require updating that lowest key either before write out or
524 * every time it changed. Instead, the objectid of the lowest key is stored
525 * along with the level of the tree block. This provides a hint
526 * about where in the btree the block can be found. Searches through the
527 * btree only need to look for a pointer to that block, so they stop one
528 * level higher than the level recorded in the backref.
529 *
530 * Some btrees do not do reference counting on their extents. These
531 * include the extent tree and the tree of tree roots. Backrefs for these
532 * trees always have a generation of zero.
533 *
534 * When a tree block is created, back references are inserted:
535 *
536 * (root->root_key.objectid, trans->transid or zero, level, lowest_key_objectid)
537 *
538 * When a tree block is cow'd in a reference counted root,
539 * new back references are added for all the blocks it points to.
540 * These are of the form (trans->transid will have increased since creation):
541 *
542 * (root->root_key.objectid, trans->transid, level, lowest_key_objectid)
543 *
544 * Because the lowest_key_objectid and the level are just hints
545 * they are not used when backrefs are deleted. When a backref is deleted:
546 *
547 * if backref was for a tree root:
548 * root_objectid = root->root_key.objectid
549 * else
550 * root_objectid = btrfs_header_owner(parent)
551 *
552 * (root_objectid, btrfs_header_generation(parent) or zero, 0, 0)
553 *
554 * Back Reference Key hashing:
555 *
556 * Back references have four fields, each 64 bits long. Unfortunately,
557 * This is hashed into a single 64 bit number and placed into the key offset.
558 * The key objectid corresponds to the first byte in the extent, and the
559 * key type is set to BTRFS_EXTENT_REF_KEY
560 */
561 int btrfs_insert_extent_backref(struct btrfs_trans_handle *trans,
562 struct btrfs_root *root,
563 struct btrfs_path *path, u64 bytenr,
564 u64 root_objectid, u64 ref_generation,
565 u64 owner, u64 owner_offset)
566 {
567 u64 hash;
568 struct btrfs_key key;
569 struct btrfs_extent_ref ref;
570 struct btrfs_extent_ref *disk_ref;
571 int ret;
572
573 btrfs_set_stack_ref_root(&ref, root_objectid);
574 btrfs_set_stack_ref_generation(&ref, ref_generation);
575 btrfs_set_stack_ref_objectid(&ref, owner);
576 btrfs_set_stack_ref_offset(&ref, owner_offset);
577
578 hash = hash_extent_ref(root_objectid, ref_generation, owner,
579 owner_offset);
580 key.offset = hash;
581 key.objectid = bytenr;
582 key.type = BTRFS_EXTENT_REF_KEY;
583
584 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(ref));
585 while (ret == -EEXIST) {
586 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
587 struct btrfs_extent_ref);
588 if (match_extent_ref(path->nodes[0], disk_ref, &ref))
589 goto out;
590 key.offset++;
591 btrfs_release_path(root, path);
592 ret = btrfs_insert_empty_item(trans, root, path, &key,
593 sizeof(ref));
594 }
595 if (ret)
596 goto out;
597 disk_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
598 struct btrfs_extent_ref);
599 write_extent_buffer(path->nodes[0], &ref, (unsigned long)disk_ref,
600 sizeof(ref));
601 btrfs_mark_buffer_dirty(path->nodes[0]);
602 out:
603 btrfs_release_path(root, path);
604 return ret;
605 }
606
607 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
608 struct btrfs_root *root,
609 u64 bytenr, u64 num_bytes,
610 u64 root_objectid, u64 ref_generation,
611 u64 owner, u64 owner_offset)
612 {
613 struct btrfs_path *path;
614 int ret;
615 struct btrfs_key key;
616 struct extent_buffer *l;
617 struct btrfs_extent_item *item;
618 u32 refs;
619
620 WARN_ON(num_bytes < root->sectorsize);
621 path = btrfs_alloc_path();
622 if (!path)
623 return -ENOMEM;
624
625 key.objectid = bytenr;
626 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
627 key.offset = num_bytes;
628 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
629 0, 1);
630 if (ret < 0)
631 return ret;
632 if (ret != 0) {
633 BUG();
634 }
635 BUG_ON(ret != 0);
636 l = path->nodes[0];
637 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
638 refs = btrfs_extent_refs(l, item);
639 btrfs_set_extent_refs(l, item, refs + 1);
640 btrfs_mark_buffer_dirty(path->nodes[0]);
641
642 btrfs_release_path(root->fs_info->extent_root, path);
643
644 ret = btrfs_insert_extent_backref(trans, root->fs_info->extent_root,
645 path, bytenr, root_objectid,
646 ref_generation, owner, owner_offset);
647 BUG_ON(ret);
648 finish_current_insert(trans, root->fs_info->extent_root);
649 del_pending_extents(trans, root->fs_info->extent_root);
650
651 btrfs_free_path(path);
652 return 0;
653 }
654
655 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
656 struct btrfs_root *root)
657 {
658 finish_current_insert(trans, root->fs_info->extent_root);
659 del_pending_extents(trans, root->fs_info->extent_root);
660 return 0;
661 }
662
663 static int lookup_extent_ref(struct btrfs_trans_handle *trans,
664 struct btrfs_root *root, u64 bytenr,
665 u64 num_bytes, u32 *refs)
666 {
667 struct btrfs_path *path;
668 int ret;
669 struct btrfs_key key;
670 struct extent_buffer *l;
671 struct btrfs_extent_item *item;
672
673 WARN_ON(num_bytes < root->sectorsize);
674 path = btrfs_alloc_path();
675 key.objectid = bytenr;
676 key.offset = num_bytes;
677 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
678 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
679 0, 0);
680 if (ret < 0)
681 goto out;
682 if (ret != 0) {
683 btrfs_print_leaf(root, path->nodes[0]);
684 printk("failed to find block number %llu\n",
685 (unsigned long long)bytenr);
686 BUG();
687 }
688 l = path->nodes[0];
689 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
690 *refs = btrfs_extent_refs(l, item);
691 out:
692 btrfs_free_path(path);
693 return 0;
694 }
695
696 u32 btrfs_count_snapshots_in_path(struct btrfs_root *root,
697 struct btrfs_path *count_path,
698 u64 first_extent)
699 {
700 struct btrfs_root *extent_root = root->fs_info->extent_root;
701 struct btrfs_path *path;
702 u64 bytenr;
703 u64 found_objectid;
704 u64 root_objectid = root->root_key.objectid;
705 u32 total_count = 0;
706 u32 cur_count;
707 u32 refs;
708 u32 nritems;
709 int ret;
710 struct btrfs_key key;
711 struct btrfs_key found_key;
712 struct extent_buffer *l;
713 struct btrfs_extent_item *item;
714 struct btrfs_extent_ref *ref_item;
715 int level = -1;
716
717 path = btrfs_alloc_path();
718 again:
719 if (level == -1)
720 bytenr = first_extent;
721 else
722 bytenr = count_path->nodes[level]->start;
723
724 cur_count = 0;
725 key.objectid = bytenr;
726 key.offset = 0;
727
728 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
729 ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
730 if (ret < 0)
731 goto out;
732 BUG_ON(ret == 0);
733
734 l = path->nodes[0];
735 btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
736
737 if (found_key.objectid != bytenr ||
738 found_key.type != BTRFS_EXTENT_ITEM_KEY) {
739 goto out;
740 }
741
742 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
743 refs = btrfs_extent_refs(l, item);
744 while (1) {
745 nritems = btrfs_header_nritems(l);
746 if (path->slots[0] >= nritems) {
747 ret = btrfs_next_leaf(extent_root, path);
748 if (ret == 0)
749 continue;
750 break;
751 }
752 btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
753 if (found_key.objectid != bytenr)
754 break;
755 if (found_key.type != BTRFS_EXTENT_REF_KEY) {
756 path->slots[0]++;
757 continue;
758 }
759
760 cur_count++;
761 ref_item = btrfs_item_ptr(l, path->slots[0],
762 struct btrfs_extent_ref);
763 found_objectid = btrfs_ref_root(l, ref_item);
764
765 if (found_objectid != root_objectid) {
766 total_count = 2;
767 goto out;
768 }
769 total_count = 1;
770 path->slots[0]++;
771 }
772 if (cur_count == 0) {
773 total_count = 0;
774 goto out;
775 }
776 if (level >= 0 && root->node == count_path->nodes[level])
777 goto out;
778 level++;
779 btrfs_release_path(root, path);
780 goto again;
781
782 out:
783 btrfs_free_path(path);
784 return total_count;
785 }
786 int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
787 struct btrfs_root *root, u64 owner_objectid)
788 {
789 u64 generation;
790 u64 key_objectid;
791 u64 level;
792 u32 nritems;
793 struct btrfs_disk_key disk_key;
794
795 level = btrfs_header_level(root->node);
796 generation = trans->transid;
797 nritems = btrfs_header_nritems(root->node);
798 if (nritems > 0) {
799 if (level == 0)
800 btrfs_item_key(root->node, &disk_key, 0);
801 else
802 btrfs_node_key(root->node, &disk_key, 0);
803 key_objectid = btrfs_disk_key_objectid(&disk_key);
804 } else {
805 key_objectid = 0;
806 }
807 return btrfs_inc_extent_ref(trans, root, root->node->start,
808 root->node->len, owner_objectid,
809 generation, level, key_objectid);
810 }
811
812 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
813 struct extent_buffer *buf)
814 {
815 u64 bytenr;
816 u32 nritems;
817 struct btrfs_key key;
818 struct btrfs_file_extent_item *fi;
819 int i;
820 int level;
821 int ret;
822 int faili;
823
824 if (!root->ref_cows)
825 return 0;
826
827 level = btrfs_header_level(buf);
828 nritems = btrfs_header_nritems(buf);
829 for (i = 0; i < nritems; i++) {
830 if (level == 0) {
831 u64 disk_bytenr;
832 btrfs_item_key_to_cpu(buf, &key, i);
833 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
834 continue;
835 fi = btrfs_item_ptr(buf, i,
836 struct btrfs_file_extent_item);
837 if (btrfs_file_extent_type(buf, fi) ==
838 BTRFS_FILE_EXTENT_INLINE)
839 continue;
840 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
841 if (disk_bytenr == 0)
842 continue;
843 ret = btrfs_inc_extent_ref(trans, root, disk_bytenr,
844 btrfs_file_extent_disk_num_bytes(buf, fi),
845 root->root_key.objectid, trans->transid,
846 key.objectid, key.offset);
847 if (ret) {
848 faili = i;
849 goto fail;
850 }
851 } else {
852 bytenr = btrfs_node_blockptr(buf, i);
853 btrfs_node_key_to_cpu(buf, &key, i);
854 ret = btrfs_inc_extent_ref(trans, root, bytenr,
855 btrfs_level_size(root, level - 1),
856 root->root_key.objectid,
857 trans->transid,
858 level - 1, key.objectid);
859 if (ret) {
860 faili = i;
861 goto fail;
862 }
863 }
864 }
865 return 0;
866 fail:
867 WARN_ON(1);
868 #if 0
869 for (i =0; i < faili; i++) {
870 if (level == 0) {
871 u64 disk_bytenr;
872 btrfs_item_key_to_cpu(buf, &key, i);
873 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
874 continue;
875 fi = btrfs_item_ptr(buf, i,
876 struct btrfs_file_extent_item);
877 if (btrfs_file_extent_type(buf, fi) ==
878 BTRFS_FILE_EXTENT_INLINE)
879 continue;
880 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
881 if (disk_bytenr == 0)
882 continue;
883 err = btrfs_free_extent(trans, root, disk_bytenr,
884 btrfs_file_extent_disk_num_bytes(buf,
885 fi), 0);
886 BUG_ON(err);
887 } else {
888 bytenr = btrfs_node_blockptr(buf, i);
889 err = btrfs_free_extent(trans, root, bytenr,
890 btrfs_level_size(root, level - 1), 0);
891 BUG_ON(err);
892 }
893 }
894 #endif
895 return ret;
896 }
897
898 static int write_one_cache_group(struct btrfs_trans_handle *trans,
899 struct btrfs_root *root,
900 struct btrfs_path *path,
901 struct btrfs_block_group_cache *cache)
902 {
903 int ret;
904 int pending_ret;
905 struct btrfs_root *extent_root = root->fs_info->extent_root;
906 unsigned long bi;
907 struct extent_buffer *leaf;
908
909 ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
910 if (ret < 0)
911 goto fail;
912 BUG_ON(ret);
913
914 leaf = path->nodes[0];
915 bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
916 write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
917 btrfs_mark_buffer_dirty(leaf);
918 btrfs_release_path(extent_root, path);
919 fail:
920 finish_current_insert(trans, extent_root);
921 pending_ret = del_pending_extents(trans, extent_root);
922 if (ret)
923 return ret;
924 if (pending_ret)
925 return pending_ret;
926 return 0;
927
928 }
929
930 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
931 struct btrfs_root *root)
932 {
933 struct extent_io_tree *block_group_cache;
934 struct btrfs_block_group_cache *cache;
935 int ret;
936 int err = 0;
937 int werr = 0;
938 struct btrfs_path *path;
939 u64 last = 0;
940 u64 start;
941 u64 end;
942 u64 ptr;
943
944 block_group_cache = &root->fs_info->block_group_cache;
945 path = btrfs_alloc_path();
946 if (!path)
947 return -ENOMEM;
948
949 while(1) {
950 ret = find_first_extent_bit(block_group_cache, last,
951 &start, &end, BLOCK_GROUP_DIRTY);
952 if (ret)
953 break;
954
955 last = end + 1;
956 ret = get_state_private(block_group_cache, start, &ptr);
957 if (ret)
958 break;
959
960 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
961 err = write_one_cache_group(trans, root,
962 path, cache);
963 /*
964 * if we fail to write the cache group, we want
965 * to keep it marked dirty in hopes that a later
966 * write will work
967 */
968 if (err) {
969 werr = err;
970 continue;
971 }
972 clear_extent_bits(block_group_cache, start, end,
973 BLOCK_GROUP_DIRTY, GFP_NOFS);
974 }
975 btrfs_free_path(path);
976 return werr;
977 }
978
979 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
980 u64 flags)
981 {
982 struct list_head *head = &info->space_info;
983 struct list_head *cur;
984 struct btrfs_space_info *found;
985 list_for_each(cur, head) {
986 found = list_entry(cur, struct btrfs_space_info, list);
987 if (found->flags == flags)
988 return found;
989 }
990 return NULL;
991
992 }
993
994 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
995 u64 total_bytes, u64 bytes_used,
996 struct btrfs_space_info **space_info)
997 {
998 struct btrfs_space_info *found;
999
1000 found = __find_space_info(info, flags);
1001 if (found) {
1002 found->total_bytes += total_bytes;
1003 found->bytes_used += bytes_used;
1004 WARN_ON(found->total_bytes < found->bytes_used);
1005 *space_info = found;
1006 return 0;
1007 }
1008 found = kmalloc(sizeof(*found), GFP_NOFS);
1009 if (!found)
1010 return -ENOMEM;
1011
1012 list_add(&found->list, &info->space_info);
1013 found->flags = flags;
1014 found->total_bytes = total_bytes;
1015 found->bytes_used = bytes_used;
1016 found->bytes_pinned = 0;
1017 found->full = 0;
1018 *space_info = found;
1019 return 0;
1020 }
1021
1022
1023 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
1024 struct btrfs_root *extent_root, u64 alloc_bytes,
1025 u64 flags)
1026 {
1027 struct btrfs_space_info *space_info;
1028 u64 thresh;
1029 u64 start;
1030 u64 num_bytes;
1031 int ret;
1032
1033 space_info = __find_space_info(extent_root->fs_info, flags);
1034 if (!space_info) {
1035 ret = update_space_info(extent_root->fs_info, flags,
1036 0, 0, &space_info);
1037 BUG_ON(ret);
1038 }
1039 BUG_ON(!space_info);
1040
1041 if (space_info->full)
1042 return 0;
1043
1044 thresh = div_factor(space_info->total_bytes, 7);
1045 if ((space_info->bytes_used + space_info->bytes_pinned + alloc_bytes) <
1046 thresh)
1047 return 0;
1048
1049 ret = btrfs_alloc_chunk(trans, extent_root, &start, &num_bytes, flags);
1050 if (ret == -ENOSPC) {
1051 printk("space info full %llu\n", (unsigned long long)flags);
1052 space_info->full = 1;
1053 return 0;
1054 }
1055
1056 BUG_ON(ret);
1057
1058 ret = btrfs_make_block_group(trans, extent_root, 0, flags,
1059 extent_root->fs_info->chunk_root->root_key.objectid,
1060 start, num_bytes);
1061 BUG_ON(ret);
1062 return 0;
1063 }
1064
1065 static int update_block_group(struct btrfs_trans_handle *trans,
1066 struct btrfs_root *root,
1067 u64 bytenr, u64 num_bytes, int alloc,
1068 int mark_free)
1069 {
1070 struct btrfs_block_group_cache *cache;
1071 struct btrfs_fs_info *info = root->fs_info;
1072 u64 total = num_bytes;
1073 u64 old_val;
1074 u64 byte_in_group;
1075 u64 start;
1076 u64 end;
1077
1078 while(total) {
1079 cache = btrfs_lookup_block_group(info, bytenr);
1080 if (!cache) {
1081 return -1;
1082 }
1083 byte_in_group = bytenr - cache->key.objectid;
1084 WARN_ON(byte_in_group > cache->key.offset);
1085 start = cache->key.objectid;
1086 end = start + cache->key.offset - 1;
1087 set_extent_bits(&info->block_group_cache, start, end,
1088 BLOCK_GROUP_DIRTY, GFP_NOFS);
1089
1090 old_val = btrfs_block_group_used(&cache->item);
1091 num_bytes = min(total, cache->key.offset - byte_in_group);
1092 if (alloc) {
1093 old_val += num_bytes;
1094 cache->space_info->bytes_used += num_bytes;
1095 } else {
1096 old_val -= num_bytes;
1097 cache->space_info->bytes_used -= num_bytes;
1098 if (mark_free) {
1099 set_extent_dirty(&info->free_space_cache,
1100 bytenr, bytenr + num_bytes - 1,
1101 GFP_NOFS);
1102 }
1103 }
1104 btrfs_set_block_group_used(&cache->item, old_val);
1105 total -= num_bytes;
1106 bytenr += num_bytes;
1107 }
1108 return 0;
1109 }
1110
1111 static int update_pinned_extents(struct btrfs_root *root,
1112 u64 bytenr, u64 num, int pin)
1113 {
1114 u64 len;
1115 struct btrfs_block_group_cache *cache;
1116 struct btrfs_fs_info *fs_info = root->fs_info;
1117
1118 if (pin) {
1119 set_extent_dirty(&fs_info->pinned_extents,
1120 bytenr, bytenr + num - 1, GFP_NOFS);
1121 } else {
1122 clear_extent_dirty(&fs_info->pinned_extents,
1123 bytenr, bytenr + num - 1, GFP_NOFS);
1124 }
1125 while (num > 0) {
1126 cache = btrfs_lookup_block_group(fs_info, bytenr);
1127 WARN_ON(!cache);
1128 len = min(num, cache->key.offset -
1129 (bytenr - cache->key.objectid));
1130 if (pin) {
1131 cache->pinned += len;
1132 cache->space_info->bytes_pinned += len;
1133 fs_info->total_pinned += len;
1134 } else {
1135 cache->pinned -= len;
1136 cache->space_info->bytes_pinned -= len;
1137 fs_info->total_pinned -= len;
1138 }
1139 bytenr += len;
1140 num -= len;
1141 }
1142 return 0;
1143 }
1144
1145 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
1146 {
1147 u64 last = 0;
1148 u64 start;
1149 u64 end;
1150 struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
1151 int ret;
1152
1153 while(1) {
1154 ret = find_first_extent_bit(pinned_extents, last,
1155 &start, &end, EXTENT_DIRTY);
1156 if (ret)
1157 break;
1158 set_extent_dirty(copy, start, end, GFP_NOFS);
1159 last = end + 1;
1160 }
1161 return 0;
1162 }
1163
1164 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
1165 struct btrfs_root *root,
1166 struct extent_io_tree *unpin)
1167 {
1168 u64 start;
1169 u64 end;
1170 int ret;
1171 struct extent_io_tree *free_space_cache;
1172 free_space_cache = &root->fs_info->free_space_cache;
1173
1174 while(1) {
1175 ret = find_first_extent_bit(unpin, 0, &start, &end,
1176 EXTENT_DIRTY);
1177 if (ret)
1178 break;
1179 update_pinned_extents(root, start, end + 1 - start, 0);
1180 clear_extent_dirty(unpin, start, end, GFP_NOFS);
1181 set_extent_dirty(free_space_cache, start, end, GFP_NOFS);
1182 }
1183 return 0;
1184 }
1185
1186 static int finish_current_insert(struct btrfs_trans_handle *trans,
1187 struct btrfs_root *extent_root)
1188 {
1189 u64 start;
1190 u64 end;
1191 struct btrfs_fs_info *info = extent_root->fs_info;
1192 struct extent_buffer *eb;
1193 struct btrfs_path *path;
1194 struct btrfs_key ins;
1195 struct btrfs_disk_key first;
1196 struct btrfs_extent_item extent_item;
1197 int ret;
1198 int level;
1199 int err = 0;
1200
1201 btrfs_set_stack_extent_refs(&extent_item, 1);
1202 btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
1203 path = btrfs_alloc_path();
1204
1205 while(1) {
1206 ret = find_first_extent_bit(&info->extent_ins, 0, &start,
1207 &end, EXTENT_LOCKED);
1208 if (ret)
1209 break;
1210
1211 ins.objectid = start;
1212 ins.offset = end + 1 - start;
1213 err = btrfs_insert_item(trans, extent_root, &ins,
1214 &extent_item, sizeof(extent_item));
1215 clear_extent_bits(&info->extent_ins, start, end, EXTENT_LOCKED,
1216 GFP_NOFS);
1217 eb = read_tree_block(extent_root, ins.objectid, ins.offset);
1218 level = btrfs_header_level(eb);
1219 if (level == 0) {
1220 btrfs_item_key(eb, &first, 0);
1221 } else {
1222 btrfs_node_key(eb, &first, 0);
1223 }
1224 err = btrfs_insert_extent_backref(trans, extent_root, path,
1225 start, extent_root->root_key.objectid,
1226 0, level,
1227 btrfs_disk_key_objectid(&first));
1228 BUG_ON(err);
1229 free_extent_buffer(eb);
1230 }
1231 btrfs_free_path(path);
1232 return 0;
1233 }
1234
1235 static int pin_down_bytes(struct btrfs_root *root, u64 bytenr, u32 num_bytes,
1236 int pending)
1237 {
1238 int err = 0;
1239 struct extent_buffer *buf;
1240
1241 if (!pending) {
1242 buf = btrfs_find_tree_block(root, bytenr, num_bytes);
1243 if (buf) {
1244 if (btrfs_buffer_uptodate(buf)) {
1245 u64 transid =
1246 root->fs_info->running_transaction->transid;
1247 if (btrfs_header_generation(buf) == transid) {
1248 free_extent_buffer(buf);
1249 return 1;
1250 }
1251 }
1252 free_extent_buffer(buf);
1253 }
1254 update_pinned_extents(root, bytenr, num_bytes, 1);
1255 } else {
1256 set_extent_bits(&root->fs_info->pending_del,
1257 bytenr, bytenr + num_bytes - 1,
1258 EXTENT_LOCKED, GFP_NOFS);
1259 }
1260 BUG_ON(err < 0);
1261 return 0;
1262 }
1263
1264 /*
1265 * remove an extent from the root, returns 0 on success
1266 */
1267 static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1268 *root, u64 bytenr, u64 num_bytes,
1269 u64 root_objectid, u64 ref_generation,
1270 u64 owner_objectid, u64 owner_offset, int pin,
1271 int mark_free)
1272 {
1273 struct btrfs_path *path;
1274 struct btrfs_key key;
1275 struct btrfs_fs_info *info = root->fs_info;
1276 struct btrfs_extent_ops *ops = info->extent_ops;
1277 struct btrfs_root *extent_root = info->extent_root;
1278 struct extent_buffer *leaf;
1279 int ret;
1280 int extent_slot = 0;
1281 int found_extent = 0;
1282 int num_to_del = 1;
1283 struct btrfs_extent_item *ei;
1284 u32 refs;
1285
1286 key.objectid = bytenr;
1287 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1288 key.offset = num_bytes;
1289
1290 path = btrfs_alloc_path();
1291 if (!path)
1292 return -ENOMEM;
1293
1294 ret = lookup_extent_backref(trans, extent_root, path,
1295 bytenr, root_objectid,
1296 ref_generation,
1297 owner_objectid, owner_offset, 1);
1298 if (ret == 0) {
1299 struct btrfs_key found_key;
1300 extent_slot = path->slots[0];
1301 while(extent_slot > 0) {
1302 extent_slot--;
1303 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1304 extent_slot);
1305 if (found_key.objectid != bytenr)
1306 break;
1307 if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
1308 found_key.offset == num_bytes) {
1309 found_extent = 1;
1310 break;
1311 }
1312 if (path->slots[0] - extent_slot > 5)
1313 break;
1314 }
1315 if (!found_extent)
1316 ret = btrfs_del_item(trans, extent_root, path);
1317 } else {
1318 btrfs_print_leaf(extent_root, path->nodes[0]);
1319 WARN_ON(1);
1320 printk("Unable to find ref byte nr %llu root %llu "
1321 " gen %llu owner %llu offset %llu\n",
1322 (unsigned long long)bytenr,
1323 (unsigned long long)root_objectid,
1324 (unsigned long long)ref_generation,
1325 (unsigned long long)owner_objectid,
1326 (unsigned long long)owner_offset);
1327 }
1328 if (!found_extent) {
1329 btrfs_release_path(extent_root, path);
1330 ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
1331 if (ret < 0)
1332 return ret;
1333 BUG_ON(ret);
1334 extent_slot = path->slots[0];
1335 }
1336
1337 leaf = path->nodes[0];
1338 ei = btrfs_item_ptr(leaf, extent_slot,
1339 struct btrfs_extent_item);
1340 refs = btrfs_extent_refs(leaf, ei);
1341 BUG_ON(refs == 0);
1342 refs -= 1;
1343 btrfs_set_extent_refs(leaf, ei, refs);
1344
1345 btrfs_mark_buffer_dirty(leaf);
1346
1347 if (refs == 0 && found_extent && path->slots[0] == extent_slot + 1) {
1348 /* if the back ref and the extent are next to each other
1349 * they get deleted below in one shot
1350 */
1351 path->slots[0] = extent_slot;
1352 num_to_del = 2;
1353 } else if (found_extent) {
1354 /* otherwise delete the extent back ref */
1355 ret = btrfs_del_item(trans, extent_root, path);
1356 BUG_ON(ret);
1357 /* if refs are 0, we need to setup the path for deletion */
1358 if (refs == 0) {
1359 btrfs_release_path(extent_root, path);
1360 ret = btrfs_search_slot(trans, extent_root, &key, path,
1361 -1, 1);
1362 if (ret < 0)
1363 return ret;
1364 BUG_ON(ret);
1365 }
1366 }
1367
1368 if (refs == 0) {
1369 u64 super_used;
1370 u64 root_used;
1371
1372 if (pin) {
1373 ret = pin_down_bytes(root, bytenr, num_bytes, 0);
1374 if (ret > 0)
1375 mark_free = 1;
1376 BUG_ON(ret < 0);
1377 }
1378
1379 /* block accounting for super block */
1380 super_used = btrfs_super_bytes_used(&info->super_copy);
1381 btrfs_set_super_bytes_used(&info->super_copy,
1382 super_used - num_bytes);
1383
1384 /* block accounting for root item */
1385 root_used = btrfs_root_used(&root->root_item);
1386 btrfs_set_root_used(&root->root_item,
1387 root_used - num_bytes);
1388 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
1389 num_to_del);
1390 if (ret)
1391 return ret;
1392
1393 if (ops && ops->free_extent)
1394 ops->free_extent(root, bytenr, num_bytes);
1395
1396 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
1397 mark_free);
1398 BUG_ON(ret);
1399 }
1400 btrfs_free_path(path);
1401 finish_current_insert(trans, extent_root);
1402 return ret;
1403 }
1404
1405 /*
1406 * find all the blocks marked as pending in the radix tree and remove
1407 * them from the extent map
1408 */
1409 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
1410 btrfs_root *extent_root)
1411 {
1412 int ret;
1413 int err = 0;
1414 u64 start;
1415 u64 end;
1416 struct extent_io_tree *pending_del;
1417 struct extent_io_tree *pinned_extents;
1418
1419 pending_del = &extent_root->fs_info->pending_del;
1420 pinned_extents = &extent_root->fs_info->pinned_extents;
1421
1422 while(1) {
1423 ret = find_first_extent_bit(pending_del, 0, &start, &end,
1424 EXTENT_LOCKED);
1425 if (ret)
1426 break;
1427 update_pinned_extents(extent_root, start, end + 1 - start, 1);
1428 clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
1429 GFP_NOFS);
1430 ret = __free_extent(trans, extent_root,
1431 start, end + 1 - start,
1432 extent_root->root_key.objectid,
1433 0, 0, 0, 0, 0);
1434 if (ret)
1435 err = ret;
1436 }
1437 return err;
1438 }
1439
1440 /*
1441 * remove an extent from the root, returns 0 on success
1442 */
1443 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
1444 *root, u64 bytenr, u64 num_bytes,
1445 u64 root_objectid, u64 ref_generation,
1446 u64 owner_objectid, u64 owner_offset, int pin)
1447 {
1448 struct btrfs_root *extent_root = root->fs_info->extent_root;
1449 int pending_ret;
1450 int ret;
1451
1452 WARN_ON(num_bytes < root->sectorsize);
1453 if (!root->ref_cows)
1454 ref_generation = 0;
1455
1456 if (root == extent_root) {
1457 pin_down_bytes(root, bytenr, num_bytes, 1);
1458 return 0;
1459 }
1460 ret = __free_extent(trans, root, bytenr, num_bytes, root_objectid,
1461 ref_generation, owner_objectid, owner_offset,
1462 pin, pin == 0);
1463 pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
1464 return ret ? ret : pending_ret;
1465 }
1466
1467 static u64 stripe_align(struct btrfs_root *root, u64 val)
1468 {
1469 u64 mask = ((u64)root->stripesize - 1);
1470 u64 ret = (val + mask) & ~mask;
1471 return ret;
1472 }
1473
1474 /*
1475 * walks the btree of allocated extents and find a hole of a given size.
1476 * The key ins is changed to record the hole:
1477 * ins->objectid == block start
1478 * ins->flags = BTRFS_EXTENT_ITEM_KEY
1479 * ins->offset == number of blocks
1480 * Any available blocks before search_start are skipped.
1481 */
1482 static int noinline find_free_extent(struct btrfs_trans_handle *trans,
1483 struct btrfs_root *orig_root,
1484 u64 num_bytes, u64 empty_size,
1485 u64 search_start, u64 search_end,
1486 u64 hint_byte, struct btrfs_key *ins,
1487 u64 exclude_start, u64 exclude_nr,
1488 int data)
1489 {
1490 int ret;
1491 u64 orig_search_start = search_start;
1492 struct btrfs_root * root = orig_root->fs_info->extent_root;
1493 struct btrfs_fs_info *info = root->fs_info;
1494 u64 total_needed = num_bytes;
1495 struct btrfs_block_group_cache *block_group;
1496 int full_scan = 0;
1497 int wrapped = 0;
1498
1499 WARN_ON(num_bytes < root->sectorsize);
1500 btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
1501
1502 if (search_end == (u64)-1)
1503 search_end = btrfs_super_total_bytes(&info->super_copy);
1504
1505 if (hint_byte) {
1506 block_group = btrfs_lookup_block_group(info, hint_byte);
1507 if (!block_group)
1508 hint_byte = search_start;
1509 block_group = btrfs_find_block_group(root, block_group,
1510 hint_byte, data, 1);
1511 } else {
1512 block_group = btrfs_find_block_group(root,
1513 trans->block_group,
1514 search_start, data, 1);
1515 }
1516
1517 total_needed += empty_size;
1518
1519 check_failed:
1520 if (!block_group) {
1521 block_group = btrfs_lookup_block_group(info, search_start);
1522 if (!block_group)
1523 block_group = btrfs_lookup_block_group(info,
1524 orig_search_start);
1525 }
1526 ret = find_search_start(root, &block_group, &search_start,
1527 total_needed, data);
1528 if (ret)
1529 goto error;
1530
1531 search_start = stripe_align(root, search_start);
1532 ins->objectid = search_start;
1533 ins->offset = num_bytes;
1534
1535 if (ins->objectid + num_bytes >= search_end)
1536 goto enospc;
1537
1538 if (ins->objectid + num_bytes >
1539 block_group->key.objectid + block_group->key.offset) {
1540 search_start = block_group->key.objectid +
1541 block_group->key.offset;
1542 goto new_group;
1543 }
1544
1545 if (test_range_bit(&info->extent_ins, ins->objectid,
1546 ins->objectid + num_bytes -1, EXTENT_LOCKED, 0)) {
1547 search_start = ins->objectid + num_bytes;
1548 goto new_group;
1549 }
1550
1551 if (test_range_bit(&info->pinned_extents, ins->objectid,
1552 ins->objectid + num_bytes -1, EXTENT_DIRTY, 0)) {
1553 search_start = ins->objectid + num_bytes;
1554 goto new_group;
1555 }
1556
1557 if (exclude_nr > 0 && (ins->objectid + num_bytes > exclude_start &&
1558 ins->objectid < exclude_start + exclude_nr)) {
1559 search_start = exclude_start + exclude_nr;
1560 goto new_group;
1561 }
1562
1563 if (!(data & BTRFS_BLOCK_GROUP_DATA)) {
1564 block_group = btrfs_lookup_block_group(info, ins->objectid);
1565 if (block_group)
1566 trans->block_group = block_group;
1567 }
1568 ins->offset = num_bytes;
1569 return 0;
1570
1571 new_group:
1572 if (search_start + num_bytes >= search_end) {
1573 enospc:
1574 search_start = orig_search_start;
1575 if (full_scan) {
1576 ret = -ENOSPC;
1577 goto error;
1578 }
1579 if (wrapped) {
1580 if (!full_scan)
1581 total_needed -= empty_size;
1582 full_scan = 1;
1583 } else
1584 wrapped = 1;
1585 }
1586 block_group = btrfs_lookup_block_group(info, search_start);
1587 cond_resched();
1588 block_group = btrfs_find_block_group(root, block_group,
1589 search_start, data, 0);
1590 goto check_failed;
1591
1592 error:
1593 return ret;
1594 }
1595 /*
1596 * finds a free extent and does all the dirty work required for allocation
1597 * returns the key for the extent through ins, and a tree buffer for
1598 * the first block of the extent through buf.
1599 *
1600 * returns 0 if everything worked, non-zero otherwise.
1601 */
1602 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
1603 struct btrfs_root *root,
1604 u64 num_bytes, u64 root_objectid, u64 ref_generation,
1605 u64 owner, u64 owner_offset,
1606 u64 empty_size, u64 hint_byte,
1607 u64 search_end, struct btrfs_key *ins, int data)
1608 {
1609 int ret;
1610 int pending_ret;
1611 u64 super_used, root_used;
1612 u64 search_start = 0;
1613 struct btrfs_fs_info *info = root->fs_info;
1614 struct btrfs_extent_ops *ops = info->extent_ops;
1615 u32 sizes[2];
1616 struct btrfs_root *extent_root = info->extent_root;
1617 struct btrfs_path *path;
1618 struct btrfs_extent_item *extent_item;
1619 struct btrfs_extent_ref *ref;
1620 struct btrfs_key keys[2];
1621
1622 if (data) {
1623 data = BTRFS_BLOCK_GROUP_DATA;
1624 } else if (root == root->fs_info->chunk_root ||
1625 info->force_system_allocs) {
1626 data = BTRFS_BLOCK_GROUP_SYSTEM;
1627 } else {
1628 data = BTRFS_BLOCK_GROUP_METADATA;
1629 }
1630
1631 if (root->ref_cows) {
1632 if (!(data & BTRFS_BLOCK_GROUP_METADATA)) {
1633 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
1634 num_bytes,
1635 BTRFS_BLOCK_GROUP_METADATA);
1636 BUG_ON(ret);
1637 }
1638 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
1639 num_bytes + 2 * 1024 * 1024, data);
1640 BUG_ON(ret);
1641 }
1642
1643 WARN_ON(num_bytes < root->sectorsize);
1644 if (ops && ops->alloc_extent) {
1645 ret = ops->alloc_extent(root, num_bytes, hint_byte, ins);
1646 } else {
1647 ret = find_free_extent(trans, root, num_bytes, empty_size,
1648 search_start, search_end, hint_byte,
1649 ins, trans->alloc_exclude_start,
1650 trans->alloc_exclude_nr, data);
1651 }
1652 BUG_ON(ret);
1653 if (ret)
1654 return ret;
1655
1656 /* block accounting for super block */
1657 super_used = btrfs_super_bytes_used(&info->super_copy);
1658 btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
1659
1660 /* block accounting for root item */
1661 root_used = btrfs_root_used(&root->root_item);
1662 btrfs_set_root_used(&root->root_item, root_used + num_bytes);
1663
1664 clear_extent_dirty(&root->fs_info->free_space_cache,
1665 ins->objectid, ins->objectid + ins->offset - 1,
1666 GFP_NOFS);
1667
1668 if (root == extent_root) {
1669 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
1670 ins->objectid + ins->offset - 1,
1671 EXTENT_LOCKED, GFP_NOFS);
1672 goto update_block;
1673 }
1674
1675 WARN_ON(trans->alloc_exclude_nr);
1676 trans->alloc_exclude_start = ins->objectid;
1677 trans->alloc_exclude_nr = ins->offset;
1678
1679 memcpy(&keys[0], ins, sizeof(*ins));
1680 keys[1].offset = hash_extent_ref(root_objectid, ref_generation,
1681 owner, owner_offset);
1682 keys[1].objectid = ins->objectid;
1683 keys[1].type = BTRFS_EXTENT_REF_KEY;
1684 sizes[0] = sizeof(*extent_item);
1685 sizes[1] = sizeof(*ref);
1686
1687 path = btrfs_alloc_path();
1688 BUG_ON(!path);
1689
1690 ret = btrfs_insert_empty_items(trans, extent_root, path, keys,
1691 sizes, 2);
1692
1693 BUG_ON(ret);
1694 extent_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
1695 struct btrfs_extent_item);
1696 btrfs_set_extent_refs(path->nodes[0], extent_item, 1);
1697 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
1698 struct btrfs_extent_ref);
1699
1700 btrfs_set_ref_root(path->nodes[0], ref, root_objectid);
1701 btrfs_set_ref_generation(path->nodes[0], ref, ref_generation);
1702 btrfs_set_ref_objectid(path->nodes[0], ref, owner);
1703 btrfs_set_ref_offset(path->nodes[0], ref, owner_offset);
1704
1705 btrfs_mark_buffer_dirty(path->nodes[0]);
1706
1707 trans->alloc_exclude_start = 0;
1708 trans->alloc_exclude_nr = 0;
1709 btrfs_free_path(path);
1710 finish_current_insert(trans, extent_root);
1711 pending_ret = del_pending_extents(trans, extent_root);
1712
1713 if (ret) {
1714 return ret;
1715 }
1716 if (pending_ret) {
1717 return pending_ret;
1718 }
1719
1720 update_block:
1721 ret = update_block_group(trans, root, ins->objectid, ins->offset, 1, 0);
1722 if (ret) {
1723 printk("update block group failed for %llu %llu\n",
1724 (unsigned long long)ins->objectid,
1725 (unsigned long long)ins->offset);
1726 BUG();
1727 }
1728 return 0;
1729 }
1730
1731 /*
1732 * helper function to allocate a block for a given tree
1733 * returns the tree buffer or NULL.
1734 */
1735 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1736 struct btrfs_root *root,
1737 u32 blocksize,
1738 u64 root_objectid, u64 hint,
1739 u64 empty_size)
1740 {
1741 u64 ref_generation;
1742
1743 if (root->ref_cows)
1744 ref_generation = trans->transid;
1745 else
1746 ref_generation = 0;
1747
1748
1749 return __btrfs_alloc_free_block(trans, root, blocksize, root_objectid,
1750 ref_generation, 0, 0, hint, empty_size);
1751 }
1752
1753 /*
1754 * helper function to allocate a block for a given tree
1755 * returns the tree buffer or NULL.
1756 */
1757 struct extent_buffer *__btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1758 struct btrfs_root *root,
1759 u32 blocksize,
1760 u64 root_objectid,
1761 u64 ref_generation,
1762 u64 first_objectid,
1763 int level,
1764 u64 hint,
1765 u64 empty_size)
1766 {
1767 struct btrfs_key ins;
1768 int ret;
1769 struct extent_buffer *buf;
1770
1771 ret = btrfs_alloc_extent(trans, root, blocksize,
1772 root_objectid, ref_generation,
1773 level, first_objectid, empty_size, hint,
1774 (u64)-1, &ins, 0);
1775 if (ret) {
1776 BUG_ON(ret > 0);
1777 return ERR_PTR(ret);
1778 }
1779 buf = btrfs_find_create_tree_block(root, ins.objectid, blocksize);
1780 if (!buf) {
1781 btrfs_free_extent(trans, root, ins.objectid, blocksize,
1782 root->root_key.objectid, ref_generation,
1783 0, 0, 0);
1784 BUG_ON(1);
1785 return ERR_PTR(-ENOMEM);
1786 }
1787 btrfs_set_buffer_uptodate(buf);
1788 trans->blocks_used++;
1789 return buf;
1790 }
1791
1792 static int noinline drop_leaf_ref(struct btrfs_trans_handle *trans,
1793 struct btrfs_root *root,
1794 struct extent_buffer *leaf)
1795 {
1796 u64 leaf_owner;
1797 u64 leaf_generation;
1798 struct btrfs_key key;
1799 struct btrfs_file_extent_item *fi;
1800 int i;
1801 int nritems;
1802 int ret;
1803
1804 BUG_ON(!btrfs_is_leaf(leaf));
1805 nritems = btrfs_header_nritems(leaf);
1806 leaf_owner = btrfs_header_owner(leaf);
1807 leaf_generation = btrfs_header_generation(leaf);
1808
1809 for (i = 0; i < nritems; i++) {
1810 u64 disk_bytenr;
1811
1812 btrfs_item_key_to_cpu(leaf, &key, i);
1813 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1814 continue;
1815 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1816 if (btrfs_file_extent_type(leaf, fi) ==
1817 BTRFS_FILE_EXTENT_INLINE)
1818 continue;
1819 /*
1820 * FIXME make sure to insert a trans record that
1821 * repeats the snapshot del on crash
1822 */
1823 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1824 if (disk_bytenr == 0)
1825 continue;
1826 ret = btrfs_free_extent(trans, root, disk_bytenr,
1827 btrfs_file_extent_disk_num_bytes(leaf, fi),
1828 leaf_owner, leaf_generation,
1829 key.objectid, key.offset, 0);
1830 BUG_ON(ret);
1831 }
1832 return 0;
1833 }
1834
1835 static void noinline reada_walk_down(struct btrfs_root *root,
1836 struct extent_buffer *node,
1837 int slot)
1838 {
1839 u64 bytenr;
1840 u64 last = 0;
1841 u32 nritems;
1842 u32 refs;
1843 u32 blocksize;
1844 int ret;
1845 int i;
1846 int level;
1847 int skipped = 0;
1848
1849 nritems = btrfs_header_nritems(node);
1850 level = btrfs_header_level(node);
1851 if (level)
1852 return;
1853
1854 for (i = slot; i < nritems && skipped < 32; i++) {
1855 bytenr = btrfs_node_blockptr(node, i);
1856 if (last && ((bytenr > last && bytenr - last > 32 * 1024) ||
1857 (last > bytenr && last - bytenr > 32 * 1024))) {
1858 skipped++;
1859 continue;
1860 }
1861 blocksize = btrfs_level_size(root, level - 1);
1862 if (i != slot) {
1863 ret = lookup_extent_ref(NULL, root, bytenr,
1864 blocksize, &refs);
1865 BUG_ON(ret);
1866 if (refs != 1) {
1867 skipped++;
1868 continue;
1869 }
1870 }
1871 mutex_unlock(&root->fs_info->fs_mutex);
1872 ret = readahead_tree_block(root, bytenr, blocksize);
1873 last = bytenr + blocksize;
1874 cond_resched();
1875 mutex_lock(&root->fs_info->fs_mutex);
1876 if (ret)
1877 break;
1878 }
1879 }
1880
1881 /*
1882 * helper function for drop_snapshot, this walks down the tree dropping ref
1883 * counts as it goes.
1884 */
1885 static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
1886 struct btrfs_root *root,
1887 struct btrfs_path *path, int *level)
1888 {
1889 u64 root_owner;
1890 u64 root_gen;
1891 u64 bytenr;
1892 struct extent_buffer *next;
1893 struct extent_buffer *cur;
1894 struct extent_buffer *parent;
1895 u32 blocksize;
1896 int ret;
1897 u32 refs;
1898
1899 WARN_ON(*level < 0);
1900 WARN_ON(*level >= BTRFS_MAX_LEVEL);
1901 ret = lookup_extent_ref(trans, root,
1902 path->nodes[*level]->start,
1903 path->nodes[*level]->len, &refs);
1904 BUG_ON(ret);
1905 if (refs > 1)
1906 goto out;
1907
1908 /*
1909 * walk down to the last node level and free all the leaves
1910 */
1911 while(*level >= 0) {
1912 WARN_ON(*level < 0);
1913 WARN_ON(*level >= BTRFS_MAX_LEVEL);
1914 cur = path->nodes[*level];
1915
1916 if (btrfs_header_level(cur) != *level)
1917 WARN_ON(1);
1918
1919 if (path->slots[*level] >=
1920 btrfs_header_nritems(cur))
1921 break;
1922 if (*level == 0) {
1923 ret = drop_leaf_ref(trans, root, cur);
1924 BUG_ON(ret);
1925 break;
1926 }
1927 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
1928 blocksize = btrfs_level_size(root, *level - 1);
1929 ret = lookup_extent_ref(trans, root, bytenr, blocksize, &refs);
1930 BUG_ON(ret);
1931 if (refs != 1) {
1932 parent = path->nodes[*level];
1933 root_owner = btrfs_header_owner(parent);
1934 root_gen = btrfs_header_generation(parent);
1935 path->slots[*level]++;
1936 ret = btrfs_free_extent(trans, root, bytenr,
1937 blocksize, root_owner,
1938 root_gen, 0, 0, 1);
1939 BUG_ON(ret);
1940 continue;
1941 }
1942 next = btrfs_find_tree_block(root, bytenr, blocksize);
1943 if (!next || !btrfs_buffer_uptodate(next)) {
1944 free_extent_buffer(next);
1945 reada_walk_down(root, cur, path->slots[*level]);
1946 mutex_unlock(&root->fs_info->fs_mutex);
1947 next = read_tree_block(root, bytenr, blocksize);
1948 mutex_lock(&root->fs_info->fs_mutex);
1949
1950 /* we dropped the lock, check one more time */
1951 ret = lookup_extent_ref(trans, root, bytenr,
1952 blocksize, &refs);
1953 BUG_ON(ret);
1954 if (refs != 1) {
1955 parent = path->nodes[*level];
1956 root_owner = btrfs_header_owner(parent);
1957 root_gen = btrfs_header_generation(parent);
1958
1959 path->slots[*level]++;
1960 free_extent_buffer(next);
1961 ret = btrfs_free_extent(trans, root, bytenr,
1962 blocksize,
1963 root_owner,
1964 root_gen, 0, 0, 1);
1965 BUG_ON(ret);
1966 continue;
1967 }
1968 }
1969 WARN_ON(*level <= 0);
1970 if (path->nodes[*level-1])
1971 free_extent_buffer(path->nodes[*level-1]);
1972 path->nodes[*level-1] = next;
1973 *level = btrfs_header_level(next);
1974 path->slots[*level] = 0;
1975 }
1976 out:
1977 WARN_ON(*level < 0);
1978 WARN_ON(*level >= BTRFS_MAX_LEVEL);
1979
1980 if (path->nodes[*level] == root->node) {
1981 root_owner = root->root_key.objectid;
1982 parent = path->nodes[*level];
1983 } else {
1984 parent = path->nodes[*level + 1];
1985 root_owner = btrfs_header_owner(parent);
1986 }
1987
1988 root_gen = btrfs_header_generation(parent);
1989 ret = btrfs_free_extent(trans, root, path->nodes[*level]->start,
1990 path->nodes[*level]->len,
1991 root_owner, root_gen, 0, 0, 1);
1992 free_extent_buffer(path->nodes[*level]);
1993 path->nodes[*level] = NULL;
1994 *level += 1;
1995 BUG_ON(ret);
1996 return 0;
1997 }
1998
1999 /*
2000 * helper for dropping snapshots. This walks back up the tree in the path
2001 * to find the first node higher up where we haven't yet gone through
2002 * all the slots
2003 */
2004 static int noinline walk_up_tree(struct btrfs_trans_handle *trans,
2005 struct btrfs_root *root,
2006 struct btrfs_path *path, int *level)
2007 {
2008 u64 root_owner;
2009 u64 root_gen;
2010 struct btrfs_root_item *root_item = &root->root_item;
2011 int i;
2012 int slot;
2013 int ret;
2014
2015 for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
2016 slot = path->slots[i];
2017 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
2018 struct extent_buffer *node;
2019 struct btrfs_disk_key disk_key;
2020 node = path->nodes[i];
2021 path->slots[i]++;
2022 *level = i;
2023 WARN_ON(*level == 0);
2024 btrfs_node_key(node, &disk_key, path->slots[i]);
2025 memcpy(&root_item->drop_progress,
2026 &disk_key, sizeof(disk_key));
2027 root_item->drop_level = i;
2028 return 0;
2029 } else {
2030 if (path->nodes[*level] == root->node) {
2031 root_owner = root->root_key.objectid;
2032 root_gen =
2033 btrfs_header_generation(path->nodes[*level]);
2034 } else {
2035 struct extent_buffer *node;
2036 node = path->nodes[*level + 1];
2037 root_owner = btrfs_header_owner(node);
2038 root_gen = btrfs_header_generation(node);
2039 }
2040 ret = btrfs_free_extent(trans, root,
2041 path->nodes[*level]->start,
2042 path->nodes[*level]->len,
2043 root_owner, root_gen, 0, 0, 1);
2044 BUG_ON(ret);
2045 free_extent_buffer(path->nodes[*level]);
2046 path->nodes[*level] = NULL;
2047 *level = i + 1;
2048 }
2049 }
2050 return 1;
2051 }
2052
2053 /*
2054 * drop the reference count on the tree rooted at 'snap'. This traverses
2055 * the tree freeing any blocks that have a ref count of zero after being
2056 * decremented.
2057 */
2058 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
2059 *root)
2060 {
2061 int ret = 0;
2062 int wret;
2063 int level;
2064 struct btrfs_path *path;
2065 int i;
2066 int orig_level;
2067 struct btrfs_root_item *root_item = &root->root_item;
2068
2069 path = btrfs_alloc_path();
2070 BUG_ON(!path);
2071
2072 level = btrfs_header_level(root->node);
2073 orig_level = level;
2074 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2075 path->nodes[level] = root->node;
2076 extent_buffer_get(root->node);
2077 path->slots[level] = 0;
2078 } else {
2079 struct btrfs_key key;
2080 struct btrfs_disk_key found_key;
2081 struct extent_buffer *node;
2082
2083 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2084 level = root_item->drop_level;
2085 path->lowest_level = level;
2086 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2087 if (wret < 0) {
2088 ret = wret;
2089 goto out;
2090 }
2091 node = path->nodes[level];
2092 btrfs_node_key(node, &found_key, path->slots[level]);
2093 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
2094 sizeof(found_key)));
2095 }
2096 while(1) {
2097 wret = walk_down_tree(trans, root, path, &level);
2098 if (wret < 0)
2099 ret = wret;
2100 if (wret != 0)
2101 break;
2102
2103 wret = walk_up_tree(trans, root, path, &level);
2104 if (wret < 0)
2105 ret = wret;
2106 if (wret != 0)
2107 break;
2108 /*
2109 ret = -EAGAIN;
2110 break;
2111 */
2112 }
2113 for (i = 0; i <= orig_level; i++) {
2114 if (path->nodes[i]) {
2115 free_extent_buffer(path->nodes[i]);
2116 path->nodes[i] = NULL;
2117 }
2118 }
2119 out:
2120 btrfs_free_path(path);
2121 return ret;
2122 }
2123
2124 int btrfs_free_block_groups(struct btrfs_fs_info *info)
2125 {
2126 u64 start;
2127 u64 end;
2128 u64 ptr;
2129 int ret;
2130 while(1) {
2131 ret = find_first_extent_bit(&info->block_group_cache, 0,
2132 &start, &end, (unsigned int)-1);
2133 if (ret)
2134 break;
2135 ret = get_state_private(&info->block_group_cache, start, &ptr);
2136 if (!ret)
2137 kfree((void *)(unsigned long)ptr);
2138 clear_extent_bits(&info->block_group_cache, start,
2139 end, (unsigned int)-1, GFP_NOFS);
2140 }
2141 while(1) {
2142 ret = find_first_extent_bit(&info->free_space_cache, 0,
2143 &start, &end, EXTENT_DIRTY);
2144 if (ret)
2145 break;
2146 clear_extent_dirty(&info->free_space_cache, start,
2147 end, GFP_NOFS);
2148 }
2149 return 0;
2150 }
2151
2152 int find_first_block_group(struct btrfs_root *root, struct btrfs_path *path,
2153 struct btrfs_key *key)
2154 {
2155 int ret;
2156 struct btrfs_key found_key;
2157 struct extent_buffer *leaf;
2158 int slot;
2159
2160 ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
2161 if (ret < 0)
2162 return ret;
2163 while(1) {
2164 slot = path->slots[0];
2165 leaf = path->nodes[0];
2166 if (slot >= btrfs_header_nritems(leaf)) {
2167 ret = btrfs_next_leaf(root, path);
2168 if (ret == 0)
2169 continue;
2170 if (ret < 0)
2171 goto error;
2172 break;
2173 }
2174 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2175
2176 if (found_key.objectid >= key->objectid &&
2177 found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY)
2178 return 0;
2179 path->slots[0]++;
2180 }
2181 ret = -ENOENT;
2182 error:
2183 return ret;
2184 }
2185
2186 int btrfs_read_block_groups(struct btrfs_root *root)
2187 {
2188 struct btrfs_path *path;
2189 int ret;
2190 int bit;
2191 struct btrfs_block_group_cache *cache;
2192 struct btrfs_fs_info *info = root->fs_info;
2193 struct btrfs_space_info *space_info;
2194 struct extent_io_tree *block_group_cache;
2195 struct btrfs_key key;
2196 struct btrfs_key found_key;
2197 struct extent_buffer *leaf;
2198
2199 block_group_cache = &info->block_group_cache;
2200
2201 root = info->extent_root;
2202 key.objectid = 0;
2203 key.offset = 0;
2204 btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2205 path = btrfs_alloc_path();
2206 if (!path)
2207 return -ENOMEM;
2208
2209 while(1) {
2210 ret = find_first_block_group(root, path, &key);
2211 if (ret > 0) {
2212 ret = 0;
2213 goto error;
2214 }
2215 if (ret != 0) {
2216 goto error;
2217 }
2218 leaf = path->nodes[0];
2219 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2220 cache = kmalloc(sizeof(*cache), GFP_NOFS);
2221 if (!cache) {
2222 ret = -ENOMEM;
2223 break;
2224 }
2225
2226 read_extent_buffer(leaf, &cache->item,
2227 btrfs_item_ptr_offset(leaf, path->slots[0]),
2228 sizeof(cache->item));
2229 memcpy(&cache->key, &found_key, sizeof(found_key));
2230 cache->cached = 0;
2231 cache->pinned = 0;
2232 key.objectid = found_key.objectid + found_key.offset;
2233 btrfs_release_path(root, path);
2234 cache->flags = btrfs_block_group_flags(&cache->item);
2235 bit = 0;
2236 if (cache->flags & BTRFS_BLOCK_GROUP_DATA) {
2237 bit = BLOCK_GROUP_DATA;
2238 } else if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
2239 bit = BLOCK_GROUP_SYSTEM;
2240 } else if (cache->flags & BTRFS_BLOCK_GROUP_METADATA) {
2241 bit = BLOCK_GROUP_METADATA;
2242 }
2243
2244 ret = update_space_info(info, cache->flags, found_key.offset,
2245 btrfs_block_group_used(&cache->item),
2246 &space_info);
2247 BUG_ON(ret);
2248 cache->space_info = space_info;
2249
2250 /* use EXTENT_LOCKED to prevent merging */
2251 set_extent_bits(block_group_cache, found_key.objectid,
2252 found_key.objectid + found_key.offset - 1,
2253 bit | EXTENT_LOCKED, GFP_NOFS);
2254 set_state_private(block_group_cache, found_key.objectid,
2255 (unsigned long)cache);
2256
2257 if (key.objectid >=
2258 btrfs_super_total_bytes(&info->super_copy))
2259 break;
2260 }
2261 ret = 0;
2262 error:
2263 btrfs_free_path(path);
2264 return ret;
2265 }
2266
2267 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
2268 struct btrfs_root *root, u64 bytes_used,
2269 u64 type, u64 chunk_tree, u64 chunk_objectid,
2270 u64 size)
2271 {
2272 int ret;
2273 int bit = 0;
2274 struct btrfs_root *extent_root;
2275 struct btrfs_block_group_cache *cache;
2276 struct extent_io_tree *block_group_cache;
2277
2278 extent_root = root->fs_info->extent_root;
2279 block_group_cache = &root->fs_info->block_group_cache;
2280
2281 cache = kmalloc(sizeof(*cache), GFP_NOFS);
2282 BUG_ON(!cache);
2283 cache->key.objectid = chunk_objectid;
2284 cache->key.offset = size;
2285 cache->cached = 0;
2286 btrfs_set_key_type(&cache->key, BTRFS_BLOCK_GROUP_ITEM_KEY);
2287 memset(&cache->item, 0, sizeof(cache->item));
2288 btrfs_set_block_group_used(&cache->item, bytes_used);
2289 btrfs_set_block_group_chunk_tree(&cache->item, chunk_tree);
2290 btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
2291 cache->flags = type;
2292 btrfs_set_block_group_flags(&cache->item, type);
2293
2294 ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
2295 &cache->space_info);
2296 BUG_ON(ret);
2297
2298 if (type & BTRFS_BLOCK_GROUP_DATA) {
2299 bit = BLOCK_GROUP_DATA;
2300 } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
2301 bit = BLOCK_GROUP_SYSTEM;
2302 } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
2303 bit = BLOCK_GROUP_METADATA;
2304 }
2305 set_extent_bits(block_group_cache, chunk_objectid,
2306 chunk_objectid + size - 1,
2307 bit | EXTENT_LOCKED, GFP_NOFS);
2308 set_state_private(block_group_cache, chunk_objectid,
2309 (unsigned long)cache);
2310
2311 ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
2312 sizeof(cache->item));
2313 BUG_ON(ret);
2314
2315 finish_current_insert(trans, extent_root);
2316 ret = del_pending_extents(trans, extent_root);
2317 BUG_ON(ret);
2318 return 0;
2319 }
2320
2321 u64 btrfs_hash_extent_ref(u64 root_objectid, u64 ref_generation,
2322 u64 owner, u64 owner_offset)
2323 {
2324 return hash_extent_ref(root_objectid, ref_generation,
2325 owner, owner_offset);
2326 }
2327
2328 int btrfs_update_block_group(struct btrfs_trans_handle *trans,
2329 struct btrfs_root *root,
2330 u64 bytenr, u64 num_bytes, int alloc,
2331 int mark_free)
2332 {
2333 return update_block_group(trans, root, bytenr, num_bytes,
2334 alloc, mark_free);
2335 }
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